JPWO2008152739A1 - Near field communication device, near field communication system, and near field communication method - Google Patents

Abstract

Provided is a short-range communication device capable of preventing a decrease in effective transmission rate and performing stable communication. A response signal (ACK) to the data request signal is transmitted, a propagation environment measurement signal for measuring the communication environment is received every predetermined period, and based on the time required from the transmission of the ACK to the reception of the first propagation environment measurement signal Thus, the propagation time required for communication with other short-range communication devices is calculated. Based on the propagation environment measurement signal and the propagation time, a decrease section in which the signal strength is decreased in the transmission frame including the transmission data is determined, and the transmission frame is transmitted by reducing the signal strength in the decrease section.

Description

  The present invention relates to a short-range communication device, a short-range communication system, and a short-range communication method that perform communication within a relatively narrow predetermined area.

  For example, when data communication is performed for settlement between a ticket gate device installed at a ticket gate of a station and an IC card equipped with an electronic money function, near field communication is used, for example, a reading unit of the ticket gate device. Only when an IC card exists within a short distance range of several millimeters to several tens of centimeters from each other, non-contact communication is possible between them. Such a short-range communication function is installed in various devices such as mobile phone terminals, and has begun to be used for various purposes.

  In such a short-range communication system, the distance between devices that perform non-contact communication with each other often varies relatively greatly within a very short time. As shown in FIG. 11, for example, when short-distance communication is performed between a ticket gate device installed at a ticket gate of a station and an IC card equipped with an electronic money function, it takes about 0.2 seconds. Therefore, if the output of the signal transmitted by the IC card is constant, the strength (amplitude ratio) of the signal received by the counterpart device (ticket gate device) is also as shown in FIG. Change rapidly and drastically (about 100 times).

  In such a situation, there is a high possibility that the received signal cannot be recognized correctly. Therefore, in a communication system that performs short-range communication, it is necessary to automatically adjust the signal output on the transmission side so that the intensity of the received signal does not change much even when the distance changes greatly.

  An example of a device that adjusts a signal output on a transmission side is a communication device that transmits and receives information in an UWB (Ultra Wide Band) system that transmits and receives information using an impulse train. The impulse train receiving unit and the receiving unit receive an impulse train. There is known a communication apparatus having a measuring unit that measures characteristics and a transmitting unit that transmits an impulse train at a level corresponding to a measurement result of the measuring unit (see, for example, Patent Document 1). In this communication apparatus, a transmission time slot and a reception time slot whose timings are fixed in advance are provided, and based on the strength of the signal received in the reception time slot, the signal transmitted in the transmission time slot is transmitted. The output is adjusted automatically.

JP 2003-51761 A

  However, in a conventional communication apparatus, in a communication system in which a transmission time slot and a reception time slot are fixed in advance, data transmission cannot be performed in the time slot allocated for reception, and the transmission time slot is allocated for transmission. Data cannot be received in the current time slot. For this reason, for example, when downloading a large amount of data from a server storing a large amount of data to a mobile phone terminal, each time slot cannot be used efficiently. It will reduce the speed.

  The present invention has been made in view of the above circumstances, and it is possible to prevent a decrease in effective transmission rate and to perform stable communication, a short-range communication device, a short-range communication system, and a short-range communication. It aims to provide a method.

  In order to achieve the above object, a short-range communication system according to the present invention is a short-range communication system having a first short-range communication device and a second short-range communication device that perform communication within a predetermined area. The first short-range communication device receives a propagation environment measurement signal for measuring a propagation environment transmitted from the second short-range communication device every predetermined period, and the propagation A propagation environment measurement signal transmission / reception section determination unit for determining a propagation environment measurement signal transmission / reception section, which is a section for transmitting or receiving the propagation environment measurement signal, based on the reception time of the environment measurement signal; and the propagation environment measurement signal The transmission / reception section includes a transmission frame signal generation unit that generates a transmission frame signal that does not include transmission data, and a first transmission unit that transmits the transmission frame signal generated by the transmission frame signal generation unit. The second short-range communication device has received a second transmission unit that transmits the propagation environment measurement signal at predetermined intervals, a second reception unit that receives the transmission frame signal including the transmission data, and A transmission data restoring unit that restores the transmission data by deleting data of the transmission environment measurement signal transmission / reception section from the transmission frame signal.

  With this configuration, it is possible to prevent a decrease in effective transmission rate and perform stable communication. Since it is not necessary to prepare a time slot used for transmission / reception of a propagation environment measurement signal, for example, efficient data transfer is possible in a communication system that performs asymmetric communication. In addition, by providing a section for transmitting or receiving a propagation environment measurement signal, stable communication is possible without mutual interference of signals.

  The short-range communication device of the present invention is a short-range communication device that performs communication within a predetermined region, and transmits a propagation environment measurement signal for measuring a propagation environment transmitted from another short-range communication device. A propagation environment measurement signal for determining a propagation environment measurement signal transmission / reception section, which is a section for transmitting or receiving the propagation environment measurement signal, based on a reception unit that receives each period and the reception time of the propagation environment measurement signal A transmission / reception section determination unit, a transmission frame signal generation unit that generates a transmission frame signal that does not include transmission data in the propagation environment measurement signal transmission / reception section, and a transmission that transmits the transmission frame signal generated by the transmission frame signal generation unit Part.

  With this configuration, it is possible to prevent a decrease in effective transmission rate and perform stable communication. Since it is not necessary to prepare a long time slot used for transmission / reception of a propagation environment measurement signal, efficient data transfer is possible, for example, in a communication system that performs asymmetric communication. In addition, by providing a section for transmitting or receiving a propagation environment measurement signal, stable communication is possible without mutual interference of signals.

  The short-range communication device of the present invention further includes a measurement request signal generation unit that generates a measurement request signal for requesting a propagation environment measurement signal for measuring the communication environment, and the reception unit includes: A propagation environment measurement signal transmitted from the other short-range communication device with respect to the measurement request signal is received at predetermined intervals, and the propagation environment measurement signal transmission / reception section determination unit includes a reception time of the propagation environment measurement signal and Based on the transmission time of the measurement request signal, a propagation environment measurement signal transmission / reception section that is a section for transmitting or receiving the propagation environment measurement signal is determined, and the transmission unit transmits the measurement request signal and the transmission frame. The transmission frame signal generated by the signal generation unit is transmitted.

  With this configuration, it is possible to accurately grasp at which timing a propagation environment measurement signal is received from a communication partner such as a portable terminal, and stable and efficient data transmission can be performed.

  Moreover, the short-range communication apparatus of the present invention is configured such that the transmission frame signal generation unit generates a transmission frame signal including information on the position of the propagation environment measurement signal transmission / reception section in the header.

  With this configuration, the communication partner can know at which position in the transmission frame the transmission environment measurement signal is transmitted or received, so the original transmission data is recognized based on this position information. be able to.

  The short-range communication device of the present invention further includes a region notification signal generation unit that generates a region notification signal for detecting a short-range communication device existing in the predetermined region, and the reception unit includes A data request signal for requesting the transmission data transmitted from the short-range communication device in response to an area notification signal is received, and the transmission unit transmits the area notification signal in response to the received data request signal It is configured to do.

  With this configuration, when a communication partner such as a portable terminal enters the communication range of the communication device, it is possible to perform data transmission stably and efficiently in response to various data requests requested by the communication partner. is there.

  Further, in the near field communication apparatus of the present invention, when the transmission frame signal generation unit uses the amplitude modulation method as the modulation method, the transmission frame signal generation unit sets the propagation environment measurement signal transmission / reception section to an amplitudeless state. The frame signal is generated.

  With this configuration, it is possible to construct a good communication environment without interference between the transmission device and the reception device.

  In the short-range communication apparatus of the present invention, when the transmission frame signal generation unit uses a modulation scheme other than the amplitude modulation scheme as the modulation scheme, the transmission environment measurement signal transmission / reception section is set as a null symbol. The transmission frame signal is transmitted.

  With this configuration, for example, by inserting a null symbol as a transmission signal in a signal strength decrease section, it is possible to construct a good communication environment without interference between the transmission device and the reception device.

  In the short-range communication apparatus of the present invention, the transmission frame signal generation unit generates a transmission frame signal including a header and transmission data so that the propagation environment measurement signal transmission / reception section does not overlap the header. The transmission frame signal is generated.

  With this configuration, information included in the header can be reliably notified to other short-range communication devices, and stable communication can be performed.

  Further, the short-range communication measure of the present invention includes a reception signal strength measurement unit that measures a reception signal strength of the propagation environment measurement signal received by the reception unit, and a transmission from the transmission unit based on the reception signal strength. And a transmission signal strength control unit that controls the signal strength of the transmitted signal.

  With this configuration, the signal strength of the transmission frame can be adjusted according to the signal strength of the communication signal from the communication partner, and the reception strength at the communication partner can always be adjusted to be constant. Therefore, even when the distance between the devices with the communication partner is relatively large, the strength of the received signal at the communication partner such as the portable terminal can be stabilized.

  The short-range communication device of the present invention is a short-range communication device that performs communication within a predetermined region, and includes a transmission unit that transmits a propagation environment measurement signal for measuring a propagation environment at predetermined intervals, and a transmission A receiving unit that receives a transmission frame signal including data; and the transmission environment measurement signal transmission / reception section data that is a section for transmitting or receiving the propagation environment measurement signal from the received transmission frame signal is deleted and transmitted A transmission data restoring unit that restores data.

  With this configuration, it is possible to prevent a decrease in effective transmission rate and perform stable communication. Since it is not necessary to prepare a long time slot used for transmission / reception of a propagation environment measurement signal, for example, efficient data transfer is possible even in a communication system that performs asymmetric communication. In addition, by providing a section for transmitting or receiving a propagation environment measurement signal, stable communication is possible without mutual interference of signals.

  Further, in the near field communication apparatus of the present invention, the reception unit receives the transmission frame signal including the measurement request signal and the transmission data, and the transmission unit receives the measurement request signal according to the received measurement request signal. The propagation environment measurement signal is transmitted every predetermined period.

  With this configuration, it is possible to perform data transmission stably and efficiently by receiving a transmission frame including a drop period and adjusted in signal strength based on a propagation environment measurement signal from another short-range communication device. Is possible.

  In the short-range communication device of the present invention, the transmission data restoring unit may transmit the propagation frame signal from the transmission frame signal based on information on a position of a propagation environment measurement signal transmission / reception section included in a header of the received transmission frame signal. The configuration is such that the data of the propagation environment measurement signal transmission / reception section, which is the section for transmitting or receiving the environment measurement signal, is deleted.

  With this configuration, for example, even when data with an amplitude of “00” is inserted in the lowered section, the position of the lowered section can be accurately grasped, and the data in this section can be reliably removed. The original data can be restored.

  The short-range communication apparatus of the present invention further includes a data request signal generation unit that generates a data request signal for requesting transmission data, and the reception unit receives the region notification signal, and the transmission unit Is configured to transmit the data request signal in response to the received area notification signal.

  With this configuration, when entering the communication area of a communication partner such as a server device, it is possible to transmit data stably and efficiently by requesting various data held by other short-range communication devices. is there.

  The short-range communication apparatus of the present invention is configured such that the transmission data restoration unit restores the transmission data by removing data in the propagation environment measurement signal transmission / reception section.

  With this configuration, for example, even when data with an amplitude of “00” is inserted in the lowered section, the original data can be reliably restored by removing the data in this section.

  Further, the short-range communication method of the present invention includes a step of receiving a propagation environment measurement signal for measurement of the propagation environment at predetermined intervals, and the propagation environment measurement signal based on the reception time of the propagation environment measurement signal. Determining a transmission environment measurement signal transmission / reception section, which is a section for transmission or reception, generating a transmission frame signal not including transmission data in the propagation environment measurement signal transmission / reception section, and generating the transmission frame signal And transmitting the transmission frame signal generated by the unit.

  By this method, it is possible to prevent a decrease in the effective transmission rate and perform stable communication. Since it is not necessary to prepare a long time slot used for transmission / reception of a propagation environment measurement signal, efficient data transfer is possible, for example, in a communication system that performs asymmetric communication. In addition, by providing a section for transmitting or receiving a propagation environment measurement signal, stable communication is possible without mutual interference of signals.

  The short-range communication method of the present invention includes a step of transmitting a propagation environment measurement signal for measuring a propagation environment at predetermined intervals, a step of receiving a transmission frame signal including transmission data, and the received transmission frame And deleting the data of the propagation environment measurement signal transmission / reception section, which is a section for transmitting or receiving the propagation environment measurement signal from the signal, to restore the transmission data.

  By this method, it is possible to prevent a decrease in the effective transmission rate and perform stable communication. Since it is not necessary to prepare a long time slot used for transmission / reception of a propagation environment measurement signal, for example, efficient data transfer is possible even in a communication system that performs asymmetric communication. In addition, by providing a section for transmitting or receiving a propagation environment measurement signal, stable communication is possible without mutual interference of signals.

  According to the present invention, it is possible to prevent a decrease in effective transmission rate and perform stable communication. Since it is not necessary to prepare a long time slot used for transmission / reception of a propagation environment measurement signal, for example, efficient data transfer is possible even in a communication system that performs asymmetric communication. In addition, by providing a section for transmitting or receiving a propagation environment measurement signal, stable communication is possible without mutual interference of signals.

It is a block diagram which shows an example of a structure of the short-distance communication system in the 1st Embodiment of this invention. It is a sequence diagram which shows an example of the outline of operation | movement of the near field communication system in the 1st Embodiment of this invention. (A) It is a figure which shows an example of the transmission frame signal before and behind insertion of the window area | region in the server apparatus of the 1st Embodiment of this invention. (B) It is a figure for demonstrating an example of the data transmission in the short-distance communication system of the 1st Embodiment of this invention. (C) It is a figure which shows an example of the transmission frame signal before and behind the removal of the window area | region in the portable terminal of the 1st Embodiment of this invention. It is a figure which shows an example of main operation | movement of the server apparatus in the 1st Embodiment of this invention. The figure which shows an example of operation | movement of the transmission frame signal generation part in the 1st Embodiment of this invention. It is a figure which shows an example of main operation | movement of the portable terminal in the 1st Embodiment of this invention. It is a figure which shows an example of the window area | region used in the near field communication system of the 1st Embodiment of this invention. It is a figure which shows an example of the window area | region used in the near field communication system of the 1st Embodiment of this invention. It is a figure which shows an example of a structure of the short-distance communication system in the 2nd Embodiment of this invention. It is a figure for demonstrating an example of the data transmission in the near field communication system of the 2nd Embodiment of this invention. The figure which shows an example of the relationship between time passage and the distance of short-range communication apparatuses It is a block diagram which shows an example of a structure of the short-distance communication system in the 3rd Embodiment of this invention. It is a figure for demonstrating an example of the data transmission in the 3rd short-distance communication system of this invention.

Explanation of symbols

100, 200, 300 Short-range communication system 10, 10B, 10C Server device 11 Transmission antenna 12 Reception antenna 13, 13B, 13C Short-range communication unit 14 Control unit 20, 20B, 20C Mobile terminal 21 Transmission antenna 22 Reception antenna 23, 23B , 23C Near field communication unit 24 Control unit 131 Transmission unit 132 Reception unit 133, 133B, 133C Radio control unit 141, 141C Transmission frame signal generation unit 142 Transmission amplitude control unit 143 Reception amplitude determination unit 144 Access detection unit 145, 145C Propagation environment Measurement signal transmission / reception section determination unit 146 Area notification signal generation unit 147 Measurement request signal generation unit 231 Transmission unit 232 Reception unit 233, 233B, 233C Radio control unit 241 Propagation environment measurement signal generation unit 242, 242C Transmission data restoration unit 243 Access detection 244 Data request signal generation unit W1A1, W1A2, W2A1, W2A2 Window area W1B1, W1B2, W2B1, W2B2 Window area W1C1, W1C2, W2C1, W2C2 Window area W1D1, W1D2, W2W1, W2W window , WB2, WB3 Window area

  A near field communication apparatus and a near field communication method in an embodiment of the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram showing an example of the configuration of a short-range communication system 100 according to an embodiment of the present invention. The short-range communication system 100 includes a server device 10 and a mobile terminal 20. The server device 10 has a function for data communication with the mobile terminal 20 using the short-range communication function, and for example, an automatic ticket gate device at a station can be considered. The mobile terminal 20 has a function for data communication with the server device 10 by short-range communication. For example, a mobile phone terminal equipped with electronic money or an IC card can be considered. The server device 10 is an example of a first near field communication device (or simply referred to as a near field communication device). The mobile terminal 20 is an example of a second short-range communication device (or simply referred to as a short-range communication device).

  The server device 10 includes a transmission antenna 11 and a reception antenna 12 for near field communication, a near field communication unit 13, and a control unit 14. The short-range communication unit 13 includes a transmission unit 131, a reception unit 132, and a wireless control unit 133. Further, the radio control unit 133 includes a transmission frame signal generation unit 141, a transmission amplitude control unit 142, a reception amplitude determination unit 143, an approach detection unit 144, a propagation environment measurement signal transmission / reception section determination unit 145, and a region notification signal. A generation unit 146 and a measurement request signal generation unit 147 are provided.

  The transmission unit 131 transmits data via the transmission antenna 11 using amplitude modulation.

  The receiving unit 132 receives a signal via the receiving antenna 12.

  The transmission frame signal generation unit 141 generates a transmission frame signal used when transmitting data to the mobile terminal 20 by short-range communication. The transmission frame signal generation unit 141 transmits transmission data in a propagation environment measurement signal transmission / reception section (a section for transmitting or receiving a propagation environment measurement signal) determined by a propagation environment measurement signal transmission / reception section determination unit 145 described later. Not included, a transmission frame signal including information on the position of the transmission environment measurement signal transmission / reception section is generated in the header.

  The transmission amplitude control unit 142 performs reception on the mobile terminal 20 side regardless of a change in the distance from the mobile terminal 20 based on the amplitude (or reception signal strength) of the propagation environment measurement signal determined by the reception amplitude determination unit 143. The transmission amplitude (or transmission power) is controlled so that the signal strength of the signal becomes constant. Specifically, the reception amplitude determination unit 143 determines the amplitude (or reception signal strength) of a reception signal such as a propagation environment measurement signal that the mobile terminal 20 periodically transmits, and according to the result, the transmission unit 131 The transmission amplitude is sequentially controlled.

  The approach detection unit 144 detects that the mobile terminal 20 exists within a predetermined distance from the server device 10, and the radio control unit 133 generates signals such as a measurement request signal, a region notification signal, and a transmission frame signal. To control. Specifically, first, the region notification signal generation unit 146 is caused to generate a region notification signal. When the data request signal transmitted from the mobile terminal 20 is detected, control is performed so that the measurement request signal generation unit 147 generates the measurement request signal. When the propagation environment measurement signal is detected after the measurement request signal is generated, the transmission frame signal generation unit 141 starts generation of the transmission frame signal.

  The propagation environment measurement signal transmission / reception section determination unit 145 receives, for example, the reception time of the propagation environment measurement signal (propagation environment measurement signal) transmitted from the mobile terminal 20 to the server device 10 (for example, in FIG. 3B). Based on t2 or t22), a section for transmitting or receiving a propagation environment measurement signal (the above-described propagation environment measurement signal transmission / reception section) is determined. Alternatively, the transmission time of the measurement request signal (for example, t1 or t11 in FIG. 3B), the reception time of the propagation environment measurement signal (for example, t2 or t22 in FIG. 3B), and a predetermined time required for internal processing Based on (for example, tp in FIG. 3B), the propagation environment measurement signal transmission / reception section is determined. The time or time can also be counted by the number of symbols.

  The portable terminal 20 includes a transmission antenna 21 and a reception antenna 22 for near field communication, a near field communication unit 23, and a control unit 24. The short-range communication unit 23 includes a transmission unit 231, a reception unit 232, and a wireless control unit 233. Further, the radio control unit 233 includes a propagation environment measurement signal generation unit 241, a transmission data restoration unit 242, an approach detection unit 243, and a data request signal generation unit 244.

  The transmission unit 231 transmits a signal via the transmission antenna 21 using amplitude modulation.

  The receiving unit 232 receives a signal via the receiving antenna 22.

  The propagation environment measurement signal generation unit 241 generates a predetermined propagation environment measurement signal. This propagation environment measurement signal is used for the server device 10 to control the transmission amplitude (or transmission power) so that the signal intensity when the signal is received on the mobile terminal 20 side is constant.

  The transmission data restoration unit 242 restores the header and transmission data (or payload portion) from the transmission frame signal received from the server device 10 and extracts data (or payload portion) included in the transmission frame signal. Perform the process.

  The approach detection unit 243 detects whether or not the mobile terminal 20 has entered a predetermined area where short-range communication is possible between the mobile terminal 20 and the server device 10. Specifically, a circuit for detecting a predetermined area notification signal and a measurement request signal transmitted by the server device 10 is provided. And if the area | region notification signal which the server apparatus 10 transmitted is detected, the data request signal production | generation part 244 will be made to produce | generate a data request signal. When the measurement request signal transmitted by the server device 10 is received, the propagation environment measurement signal generation unit 241 is caused to start generating the propagation environment measurement signal.

  Next, an outline of short-range communication operation between the server device 10 and the mobile terminal 20 will be described. FIG. 2 is a sequence diagram illustrating an example of an outline of the operation of the short-range communication system 100.

  First, in order to confirm whether the portable terminal 20 exists in the predetermined range in which the short distance communication of the server apparatus 10 is possible, the server apparatus 10 transmits a predetermined communication area notification signal (step S1).

  When the mobile terminal 20 enters the range in which the server device 10 can perform near field communication, the mobile terminal 20 can detect the communication area notification signal transmitted by the server device 10. When detecting the communication area notification signal, the portable terminal 20 transmits a data request signal (Req) for requesting the start of data transmission with a predetermined signal strength (step S2).

  When the server apparatus 10 receives the data request signal (Req) from the mobile terminal 20, the server apparatus 10 evaluates the reception strength (amplitude) of the received data request signal, and then sends a response signal (ACK) to the data request signal with a predetermined signal strength. (Step S3). This ACK is an example of a “measurement request signal”.

  When the mobile terminal 20 receives the response signal (ACK) from the server device 10, the mobile terminal 20 generates a predetermined signal generated by the propagation environment measurement signal generation unit 241 after a predetermined time required for internal processing (for example, tp in FIG. 3B). The propagation environment measurement signal (SG) is transmitted (step S4). Thereafter, the propagation environment measurement signal (SG) is repeatedly transmitted from the portable terminal 20 at regular time intervals until the data transmission is completed.

When the server apparatus 10 receives the first propagation environment measurement signal (SG) from the mobile terminal 20,
For example, a section (propagation environment measurement signal transmission / reception section) for transmitting or receiving the propagation environment measurement signal is determined based on the reception time of the propagation environment measurement signal (for example, t2 or t22 in FIG. 3B). . Alternatively, the transmission time of the measurement request signal (for example, t1 or t11 in FIG. 3B), the reception time of the propagation environment measurement signal (for example, t2 or t22 in FIG. 3B), and a predetermined time required for internal processing Based on (for example, tp in FIG. 3B), the propagation environment measurement signal transmission / reception section is determined. The time or time can also be counted by the number of symbols. Furthermore, the server apparatus 10 evaluates the reception amplitude of the received propagation environment measurement signal (SG), determines the transmission amplitude (or transmission power) of the signal transmitted from the transmission unit 131 based on the evaluation result, and performs control. To do. (Step S5).

  After the process of step S5, data transmission is started between the server device 10 and the portable terminal 20 (step S6).

  Next, a window area (or a propagation environment measurement signal transmission / reception section) used in the short-range communication system 100 will be described. FIG. 3A is a diagram illustrating an example of a transmission frame signal before and after insertion of a window area in the server device 10. FIG. 3B is a diagram for explaining an example of data transmission in the short-range communication system 100. FIG. 3C is a diagram showing an example of a transmission frame signal before and after the removal of the window area in the mobile terminal 20.

  In the short-range communication system 100, as shown in FIG. 3A, when data transmission is performed between the server device 10 and the mobile terminal 20, a propagation environment is included in a transmission frame signal transmitted by the server device 10. A special area (window area) such as a propagation environment measurement signal transmission / reception section that is a section for transmitting or receiving a measurement signal (for example, output (amplitude or power) may be suppressed) is required. Insert in position. In FIG. 3, sections W1A1, W1A2, ..., W2A1, W2A2, ..., W1B1, W1B2, ..., W2B1, W2B2, ... are examples of window areas.

  Here, since the window areas W1A1, W1A2,... Are windows provided to prevent interference with the propagation environment measurement signal (SG) transmitted by the mobile terminal 20, they are referred to as transmission windows W1A. Moreover, since window area | region W2A1, W2A2, ... is a window provided in order to prevent the interference with respect to the propagation environment measurement signal (SG) which the server apparatus 10 receives, it is called reception window W2A.

  Further, window areas W1B1, W1B2,... That appear in a frame received by the mobile terminal 20 are windows corresponding to the transmission window W1A and the reception window W2A, and are referred to as terminal windows W1B and W2B. The terminal window W1B is configured to include a predetermined range before and after the timing of transmitting the propagation environment measurement signal (SG).

  As shown in FIG. 3 (b), the transmission window W1A is at a timing preceding the position of the terminal window W1B by the propagation time. In addition, the reception window W2A comes before the terminal window W2B by the propagation time.

  Specifically, for example, the transmission window W1A has a predetermined time (for example, FIG. 3B) after the server apparatus 10 completes transmission of a response signal (ACK), which is an example of a measurement request signal (time t11). tp) or after a predetermined symbol corresponding thereto, a section corresponding to the length of the propagation environment measurement signal is provided every predetermined time interval (specifically, a transmission cycle of the propagation environment measurement signal) (or every predetermined symbol). Can be. If the transmission window W1A is set in this way, the transmission timing of the propagation environment measurement signal of the mobile terminal 10 and the transmission window W1A can be synchronized. In addition, the reception window W2A, specifically, for example, after the time of the round-trip propagation time or after the corresponding symbol (after t11-t2-tp in FIG. 3B) from the timing of the transmission window W1A ) To the length of the propagation environment measurement signal. If the transmission window W1A is set in this way, the transmission timing of the propagation environment measurement signal of the mobile terminal 10 and the transmission window W1A can be synchronized. The transmission window W1A corresponds to the length (t11-t1) of the response signal (ACK) and the predetermined time tp or the time t1 based on the time t1 instead of using the time t11 in FIG. 3B as a reference. You may make it provide every predetermined time interval after a predetermined symbol. The same applies to the reception window W2A.

  Such a transmission window and a reception window are inserted as a transmission window and a reception window in a transmission frame transmitted by the server device 10 as shown in FIG. Here, since the transmission unit 131 of the server apparatus 10 transmits a signal by amplitude modulation, when performing OOK (on-off-keying) modulation, a signal having a value of “00” is transmitted to the positions of the transmission window and the reception window. Thus, the transmission output (signal amplitude) can be cut off at the positions of the transmission window and the reception window.

  In addition, when the mobile terminal 20 receives a transmission frame signal including a transmission window and a reception window, the mobile terminal 20 receives a signal including a window area unrelated to data to be received by the transmission frame signal. As shown in c), from the received transmission frame signal, invalid data at the position of the transmission window and the reception window (terminal window in the mobile terminal 20) is deleted, and a header that is a data sequence to be received and The frame including the transmission data (or payload portion) is restored, and necessary data (or payload portion) is extracted.

  By using such a window area in the short-range communication system 100, a transmission signal (such as data requested by the portable terminal 20) transmitted by the server device 10 and a transmission signal (such as a propagation environment measurement signal) transmitted by the portable terminal. It is possible to perform stable data transmission without interfering with each other.

  In addition, communication can be performed without reducing transmission efficiency even in a communication system in which a transmission time slot and a reception time slot are not determined in advance or an asymmetric communication system in which the amount of data of transmission data and reception data is greatly different. It is possible.

  In FIG. 3B, the communication area notification signal is omitted. However, as shown in FIG. 2, the server device 10 transmits the communication area notification signal, and the mobile terminal 20 detects the communication area notification signal. Then, the data request signal (Req) may be transmitted.

  Next, main operations of the server apparatus 10 will be described. FIG. 4 is a diagram illustrating an example of main operations of the server device 10.

  In step S <b> 10, the transmission unit 131 transmits the communication area notification signal generated by the approach detection unit 144.

  In step S11, the receiving unit 132 confirms whether or not the data request signal (Req) from the mobile terminal 20 has been received. When the data request signal is received, the process proceeds to the next step S12.

  In step S12, the transmission unit 131 transmits a response signal (ACK) (an example of a measurement request signal) to the received data request signal. Also, the propagation environment measurement signal transmission / reception section determination unit 145 grasps the transmission time t1 or t11 at this time.

  In step S13, the receiving unit 132 checks whether or not the first propagation environment measurement signal (SG) from the mobile terminal 20 has been received. When the propagation environment measurement signal is received, the process proceeds to the next step S14.

  In step S14, the propagation environment measurement signal transmission / reception section determination unit 145 detects time t2 or t22 when the first propagation environment measurement signal (SG) is received. In addition, the reception amplitude determination unit 143 grasps the reception amplitude of the propagation environment measurement signal (SG). Further, the transmission amplitude control unit 142 determines the transmission amplitude (or transmission power) of a signal such as a transmission frame signal transmitted by the transmission unit 131 based on the grasped reception amplitude. Thereby, the received signal strength by the portable terminal 20 can be kept constant.

  In step S <b> 15, the propagation environment measurement signal transmission / reception section determination unit 145 calculates the propagation time td in the short-distance communication path between the server device 10 and the mobile terminal 20. Specifically, for example, time t2 at which reception of the propagation environment measurement signal (SG) is started at step S13 from time t1 at which transmission of the response signal (ACK) is started at step S12 or time t11 at which transmission of the response signal (ACK) is completed. Alternatively, the propagation time td is set to td = (t2−t1−tp) from the elapsed time until the time t22 when the reception of the propagation environment measurement signal (SG) is completed and the predetermined time tp (for example, predetermined) for internal processing. ) / 2. Alternatively, the round-trip propagation time 2 · td can be calculated as 2 · td = (t2−t1−tp).

  In step S16, the propagation environment measurement signal transmission / reception section determination unit 145 receives the first propagation environment measurement signal (SG) at time t2 or t22 and the propagation time td or 2 · td calculated in step S15. As described above, the interval between the transmission window W1A and the transmission window W2A is determined. That is, a section for transmitting or receiving a propagation environment measurement signal (a propagation environment measurement signal transmission / reception section) is determined.

  Based on the time t2 or t22 and the propagation time td or 2 · td, the times tx, tx2, tx3,... (See FIG. 3) at which the mobile terminal 20 transmits the propagation environment measurement signal (SG) are calculated. You can also For example, the time tx when the mobile terminal 20 first starts transmitting the propagation environment measurement signal (SG) corresponds to the propagation time td than the time t2 when the server device 10 starts receiving the first propagation environment measurement signal (SG). It can be estimated that it is only before. Moreover, since the portable terminal 20 transmits the propagation environment measurement signal (SG) every time a certain time (transmission environment measurement signal transmission cycle) elapses, the control unit 14 is an integer multiple of this certain time at the time tx. Can be estimated as tx2, tx3,.

  In step S17, the transmission frame signal generation unit 141 generates a transmission frame signal including a transmission window and a reception window, and the transmission unit 131 transmits data using the transmission frame signal. A method for generating a transmission frame signal will be described in detail later.

  In step S18, the wireless control unit 133 checks whether or not the data transmission is completed, and if not completed, repeats the process of step S17.

  Next, an example of the operation (step S17) at the time of frame generation by the transmission frame signal generation unit 141 will be further described. FIG. 5 is a diagram illustrating an example of the operation of the transmission frame signal generation unit 141.

  In step S20, the transmission frame signal generation unit 141 uses each transmission window W1A (W1A1, W1A2,...) And each reception window W2A (W2A1, W2A2,...) (See FIG. 3) as a propagation environment measurement signal. It is inserted at the position determined by the transmission / reception section determination unit 145. That is, each transmission window W1A and each reception window W2A are inserted into the propagation environment measurement signal transmission / reception section. Specifically, each reception window W2A is inserted into a section including a time after the transmission cycle of the propagation environment measurement signal from the time (from time t2 to time t22) when the first propagation environment measurement signal is received. Further, each transmission window W1A is inserted into a section including a time before the section of each reception window W2A by a round-trip propagation time (2.td). That is, each transmission window W1A is a time that is a round-trip propagation time (2.td) before the time after the transmission cycle of the propagation environment measurement signal from the time when the first propagation environment measurement signal is received (from time t2 to time t22). Is inserted in the section including

  As a result, for example, the second propagation environment measurement signal (SG) starts to be transmitted from the portable terminal 20 at time tx2, so that the transmission window W1A1 is a time before the terminal window W1B1 by the propagation time td, that is, It is formed in a predetermined range including a section from time tx2-td. Here, the predetermined range includes at least a time corresponding to the length of the propagation environment measurement signal from time tx2-td. Further, when the propagation time td elapses after the second propagation environment measurement signal (SG) is transmitted from the mobile terminal 20 at time tx2, the server device 10 starts receiving the propagation environment measurement signal (SG). Thus, the reception window W2A1 is formed at a position within a predetermined range including the time td2 + td after the terminal window W1B1 by the propagation time td. Here, the predetermined range includes at least a time corresponding to the length of the propagation environment measurement signal from time tx2 + td.

  In the same manner as described above, the window positions of the transmission windows W1A2,... And the reception windows W2A2,.

  In step S21, the transmission frame generation signal unit 141 creates a header including information on the propagation time td evaluated by the propagation environment measurement signal transmission / reception section determination unit 145, and this header is transmitted frame as shown in FIG. Place at the beginning of. Here, since the window position, that is, the propagation environment measurement signal transmission / reception section can be determined based on the propagation time td, the propagation time td can be referred to as information on the position of the propagation environment measurement signal transmission / reception section.

  In step S22, the transmission frame signal generation unit 141 starts allocating data to be transmitted in the transmission frame signal to be generated.

  In step S23, the transmission frame signal generation unit 141 confirms whether assignment of data to be transmitted has been completed, and if not completed, proceeds to the next step S24. Although not shown, the transmission data assigned here can be stored in the server device 10.

  In step S24, the transmission frame signal generation unit 141 checks whether or not the position on the transmission frame signal to which the current data is allocated corresponds to each window area, and if it is the position of the window area, the next step S25 is executed. If it is not the position of the window area, step S26 is executed.

  In step S25, the transmission frame signal generator 141 reduces the amplitude (or power) of the signal to be transmitted, using the information composed of the value “00” as the window area information, and the data in the transmission frame signal. Insert between. That is, at the position (timing) of each window region, a signal that is amplitude-modulated by the value “00” is transmitted, so that there is temporarily no signal. Then, the process returns to step S23, and data allocation is performed until allocation of data to be transmitted is completed.

  On the other hand, in step S26, the transmission frame signal generation unit 141 inserts the next data to be transmitted at the next position of the transmission frame signal.

  According to such a server device 10, when the mobile terminal 20 receives a signal from the server device 10 by providing a transmission window in a no-signal state in the transmission frame signal of the signal transmitted by the server device 10, A collision between the received signal and the propagation environment measurement signal (SG) can be prevented, and an error can be avoided in the data received by the mobile terminal 20 from the server device 10.

  Further, by providing a reception window in the no-signal state in the transmission frame signal of the signal transmitted by the server device 10, when the server device 10 receives the propagation environment measurement signal (SG) from the mobile terminal 20, the propagation environment Collision between the measurement signal (SG) and the signal transmitted by the server device 10 can be prevented, and errors that occur during measurement of the propagation environment can be suppressed.

  Furthermore, in order to suppress a change in reception intensity due to a sudden change in the distance between the server device 10 and the mobile terminal 20, the server device 10 repeatedly measures the reception status in a short period, and based on the result, transmits a transmission output. Can be updated frequently. In this case, by adjusting the transmission signal level (for example, transmission amplitude) according to the signal reception level of the server device 10, it is possible to eliminate the function of tracking the fluctuation of the signal reception level in the mobile terminal 20. Yes, it is possible to save power and simplify the portable terminal.

  Here, it has been described that the transmission frame signal is generated until the data transmission is completed after the transmission amplitude is determined once based on the propagation environment measurement signal. However, the propagation environment measurement signal is received every predetermined period. The transmission amplitude may be controlled each time. As a result, it is possible to perform communication with signal strength in consideration of the communication environment with the latest mobile terminal 20.

  Next, main operations of the mobile terminal 20 will be described. FIG. 6 is a diagram illustrating an example of main operations of the mobile terminal 20.

  In step S <b> 30, the approach detection unit 243 confirms whether the reception unit 232 has received the communication area notification signal from the server device 10. If reception of this communication area notification signal is detected, the process proceeds to step S31 and subsequent steps.

  In step S31, the approach detection unit 243 that has detected the reception of the communication area notification signal causes the data request signal generation unit to generate a data request signal. Then, the transmission unit 231 transmits the data request signal (Req) generated by the data request signal generation unit to the server device 10.

  In step S32, the approach detection unit 243 confirms whether or not the reception unit 232 has received a response signal (ACK) from the server device 10, which is an example of a measurement request signal. When the approach detection unit 243 detects reception of the response signal (ACK), the process proceeds to the next step S33.

  In step S33, the approach detection unit 243 that has detected the reception of the response signal (ACK) causes the propagation environment measurement signal generation unit to generate a propagation environment measurement signal at a predetermined period (or every time a predetermined time elapses). Let it begin. Then, the transmission unit 231 starts transmission of the propagation environment measurement signal (SG) generated by the propagation environment measurement signal generation unit 241 to the server device 10. The propagation environment measurement signal (SG) is repeatedly transmitted by the transmission unit 231 at a predetermined period from this point (or every time a certain time elapses).

  In step S <b> 34, the transmission data restoration unit 242 examines a signal transmitted from the server device 10 and confirms whether the frame header is received by the reception unit 232. When the header of the frame is received, the process proceeds to the next step S35.

  In step S35, the transmission data restoration unit 242 extracts information on the propagation time td from the received header, and grasps the position of each terminal window included in the received frame using the propagation time td.

  For example, the position of the terminal window W1B1 (the window area corresponding to the transmission window W1A1) is set at a certain time (that is, the propagation environment measurement signal of the propagation environment measurement signal) at the time tx when the mobile terminal 20 starts transmitting the first propagation environment measurement signal (SG). Since the transmission time tx2 (see FIG. 3) of the second propagation environment measurement signal (SG) can be determined by adding the generation or transmission cycle), a predetermined time including the length of the propagation environment measurement signal from time tx2 is determined. It can be grasped as a range.

  Further, the position of the terminal window W1B2 (the window area corresponding to the reception window W2A1) is a predetermined range after the round-trip propagation time (2 · td) between the mobile terminal 20 and the server device 10 from the position of the terminal window W1B1. I can grasp it. This can be calculated based on the propagation time td information extracted from the received header. The subsequent terminal windows W1B2, W2B2,.

  In step S36, the transmission data restoration unit 242 regards the data of the terminal window position in the received frame as invalid data and eliminates it, and restores the original transmission frame before inserting the window area. Then, the transmission data restoration unit 242 extracts data transmitted from this frame.

  In step S37, the transmission data restoration unit 242 confirms whether or not reception of all data has been completed.

  According to such a portable terminal 20, even if a transmission window signal or a reception window in a no-signal state is provided in the transmission frame signal of the signal transmitted by the server device 10, the transmission data restoration unit 242 ensures that the original transmission is performed. Frames can be restored, and stable and efficient data transmission can be realized.

  Next, another example of the window area used in the short-range communication system 100 will be described. FIG. 7 is a diagram illustrating an example of a window region used in the short-range communication system 100.

  For example, in a communication environment in which the distance between the server device 10 and the portable terminal 20 is about 10 cm at a transmission rate of about 1 Gbps, the interval between the transmission window and the reception window is a time length of about several symbols. These may be assigned as one window area without providing a boundary between the reception window and the reception window.

  In FIG. 7, the server apparatus 10 does not provide a transmission window and a reception window that are independent from each other in the transmission frame, and the transmission window and the reception window are combined into one window area WA (WA1, WA2,...). . In this case, since the mobile terminal 20 transmits the propagation environment measurement signal (SG) at a timing close to the head of the window area WB (WB1, WB2,...) In the frame received by the mobile terminal 20, the server device 10 Can receive the propagation environment measurement signal (SG) from the portable terminal 20 before the window area WA ends. In this case, a configuration in which the header does not necessarily include information on the propagation time td is also possible.

  By using such a window area in the short-range communication system 100, a transmission signal (such as data requested by the portable terminal 20) transmitted by the server device 10 and a transmission signal (such as a propagation environment measurement signal) transmitted by the portable terminal. It is possible to perform stable data transmission without interfering with each other.

  Even in a communication system in which a transmission time slot and a reception time slot are not predetermined or an asymmetric communication communication system in which the amount of transmission data and reception data is greatly different, communication can be performed without reducing transmission efficiency. Is possible.

  Next, still another example of the window area used in the short-range communication system 100 will be described. FIG. 8 is a diagram illustrating an example of a window area used in the short-range communication system 100.

  In FIG. 8, when the server apparatus 10 transmits a frame, a window area is not formed at the position of the header arranged at the head of the frame. That is, information is transmitted from the server device 10 in synchronization with the propagation environment measurement signal. In this case, the propagation environment measurement signal reception section determination unit 145 or the transmission frame signal generation unit 141 measures the propagation environment so that the position of the window area WA3 in the second transmission frame F2 and the header of the transmission frame do not overlap, for example. Based on the signal (SG) and the propagation time, the timing ts for starting transmission of the transmission frame signal F2 is adjusted.

  By using such a window area in the short-range communication system 100, data transmission can be performed stably and efficiently without interference between the header of the signal transmitted by the server device 10 and the propagation environment measurement signal (SG). It can be carried out.

  In particular, even when performing various data transmissions that require the use of a plurality of headers, it is possible to prevent recognition when reading header information.

  Although the example in which the transmission window and the reception window are combined into one window region has been described with reference to FIG. 8, the present invention can be applied even when the transmission window and the reception window are provided separately.

(Second Embodiment)
FIG. 9 is a diagram showing an example of the configuration of the short-range communication system 200 according to the second embodiment of the present invention. 9, the same components as those described in the short-range communication system 100 in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted or simplified. FIG. 10 is a diagram for explaining an example of data transmission in the short-range communication system 200.

  The short-range communication system 200 includes a server device 10B and a mobile terminal 20B.

  The server device 10B includes a transmission antenna 11 and a reception antenna 12 for near field communication, a near field communication unit 13B, and a control unit 14. The short-range communication unit 13B includes a transmission unit 131, a reception unit 132, and a radio control unit 133B. The radio control unit 133B includes a transmission frame signal generation unit 141B, a transmission amplitude control unit 142, a reception amplitude determination unit 143, an approach detection unit 144, a propagation environment measurement signal transmission / reception section determination unit 145, and a region notification signal. A generation unit 146 and a measurement request signal generation unit 147 are provided.

  The mobile terminal 20B includes a transmission antenna 21 and a reception antenna 22 for short-range communication, a short-range communication unit 23B, and a control unit 24. The short-range communication unit 23B includes a transmission unit 231, a reception unit 232, and a wireless control unit 233B. Further, the radio control unit 233B includes a propagation environment measurement signal generation unit 241, a transmission data restoration unit 242B, an approach detection unit 243, and a data request signal generation unit 244.

  The transmission frame signal generation unit 141B inserts a null frame at a position in the transmission window W1C (W1C1, W1C2,...) And the reception window W2C (W2C1, W2C2,...) Illustrated in FIG. Generate. A null symbol is a signal with reduced signal strength. The server apparatus 10B uses a transmission method in which redundancy is increased in consideration of a decrease in reliability of data in the transmission window W1C and the reception window W2C.

  The transmission data restoration unit 242B corresponds to the terminal window W1D (W1D1, W1D2,...) (Window area corresponding to the transmission window W1C) and W2D (W2D1, W2D2,...) (Corresponding to the reception window W2C shown in FIG. The demodulating process is performed in consideration of the fact that the reliability of the received data is lowered at the timing of the window area). Specifically, for example, error correction processing corresponding to the redundancy in which the data in the terminal window is increased is performed. Thereby, the original data can be reliably restored in the portable terminal 20B.

  Next, the operation of the short-range communication system 200 will be described. Although not shown, the transmission frame signal generation method and the transmission data restoration method are different from those of the short-range communication system 100. Specifically, in the short-range communication system 100, as shown in step S25 of FIG. 5, the frame generation unit 141 inserts “00” between transmission data at the position of the window region. In 200, the transmission frame signal generation unit 141B inserts a null symbol between the transmission data at the positions of the transmission window W1C and the reception window W2C. In the short-range communication system 100, as shown in step S36 of FIG. 6, the transmission data restoration unit 242B removes the window area from the received data and restores the original transmission frame. Then, the transmission data restoration unit 242B performs frame restoration in consideration of a decrease in data reliability at the positions of the terminal windows W1D and W2D.

  According to such a short-range communication system 200, an error occurring in data received by the mobile terminal 20B at the timing of the terminal window WD can be minimized even in a communication system other than the amplitude modulation system, and the reception window WC1. Interference with the propagation environment measurement signal (SG) received by the server device 10B at the timing is suppressed, and errors that occur during the propagation environment measurement can be suppressed.

(Third embodiment)
FIG. 12 is a diagram showing an example of the configuration of a short-range communication system 300 according to the third embodiment of the present invention. 12, the same components as those described in the short-range communication system 100 in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted or simplified. FIG. 13 is a diagram for explaining an example of data transmission in the short-range communication system 300.

  The short-range communication system 300 includes a server device 10C and a mobile terminal 20C.

  The server device 10 </ b> C includes a transmission antenna 11 and a reception antenna 12 for near field communication, a near field communication unit 13 </ b> C, and a control unit 14. The short-range communication unit 13C includes a transmission unit 131, a reception unit 132, and a radio control unit 133C. The radio control unit 133C includes a transmission frame signal generation unit 141C, a transmission amplitude control unit 142, a reception amplitude determination unit 143, an approach detection unit 144, a propagation environment measurement signal transmission / reception section determination unit 145C, and a region notification signal. A generation unit 146 and a measurement request signal generation unit 147 are provided.

  The mobile terminal 20 </ b> C includes a transmission antenna 21 and a reception antenna 22 for near field communication, a near field communication unit 23 </ b> C, and a control unit 24. The short-range communication unit 23C includes a transmission unit 231, a reception unit 232, and a radio control unit 233C. Further, the radio control unit 233C includes a propagation environment measurement signal generation unit 241, a transmission data restoration unit 242C, an approach detection unit 243, and a data request signal generation unit 244.

  FIG. 13 is a diagram for explaining an example of data transmission in the short-range communication system 300. In FIG. 13, similarly to FIG. 8 of the first embodiment, when the server device 10C transmits a frame, a window region is not formed at the position of the header arranged at the head of the frame. That is, information is transmitted from the server device 10C in synchronization with the propagation environment measurement signal. In this case, the propagation environment measurement signal reception section determination unit 145C or the transmission frame signal generation unit 141C measures the propagation environment so that the position of the window area WA3 in the second transmission frame F2 and the header of the transmission frame do not overlap, for example. Based on the signal (SG) and the propagation time, the timing ts for starting transmission of the transmission frame signal F2 is adjusted.

  By using such a window area in the short-range communication system 300, data transmission can be performed stably and efficiently without interference between the header of the signal transmitted by the server apparatus 10C and the propagation environment measurement signal (SG). It can be carried out.

  In particular, it is possible to prevent erroneous recognition when reading header information even when performing various types of data transmission that require the use of a plurality of headers.

  In addition, the propagation environment measurement signal transmission / reception section determination unit 145C of the radio control unit 133C of the server device 10C in this embodiment monitors the reception time (or reception timing) t2, tr2, tr3, etc. of the propagation environment measurement signal (SG). Based on the change from the transmission cycle of the propagation environment measurement signal at this reception time (or reception timing), the value of the propagation time td is corrected every time a header is transmitted again. Then, the transmission frame signal generation unit 141C is caused to transmit the corrected value of the propagation time td, and thereafter, the transmission frame signal is generated using the corrected value of the propagation time td. Then, the transmission data restoration unit 242C of the radio control unit 233C of the mobile terminal 20C corrects the value of the propagation time td every time the header is received again, and thereafter uses this corrected value of the propagation time td to perform transmission. Restore data. By doing in this way, even if the propagation time td changes due to a change in the distance between the server device 10C and the mobile terminal 20C, it is possible to cope with this. As a premise, it is assumed that the mobile terminal 20C determines the timing of the signal to be transmitted in synchronization with the signal received from the server device 10C. That is, the timepiece of the portable terminal 20C advances according to the propagation time td being shortened, and is delayed according to the propagation time td becoming long.

  Although the example in which the transmission window and the reception window are combined into one window area has been described with reference to FIG. 13, the present invention can be applied even when the transmission window and the reception window are provided separately.

  As described above, in the short-range communication system 300 of the present embodiment, as in the short-range communication system 100, the frame generation unit 141 transmits “00” at the position of the window area as shown in step S25 in FIG. As described in the second embodiment, the transmission frame signal generation unit 141C transmits a null symbol of the transmission data at the positions of the transmission window W1C and the reception window W2C as in the second embodiment. It may be inserted between them. Further, in the short-range communication system 300 according to the present embodiment, the transmission data restoration unit 242C removes the window area from the received data as shown in step S36 in FIG. Although the description has been made on the assumption that the original transmission frame is restored, the transmission data restoration unit 242C reduces the reliability of data at the positions of the terminal windows W1D and W2D as in the second embodiment. You may make it perform the decompression | restoration of the flame | frame considered. According to such a short-range communication system 300, an error occurring in data received by the mobile terminal 20C at the timing of the terminal window WD can be minimized even in a communication system other than the amplitude modulation system, and the reception window WC1. Interference with the propagation environment measurement signal (SG) received by the server apparatus 10C at the timing is suppressed, and errors that occur during the propagation environment measurement can be suppressed.

  INDUSTRIAL APPLICABILITY The present invention is useful as a short-range communication device, a short-range communication system, and the like that can prevent a decrease in effective transmission rate and can stably communicate.

  The present invention relates to a short-range communication device, a short-range communication system, and a short-range communication method that perform communication within a relatively narrow predetermined area.

  For example, when data communication is performed for settlement between a ticket gate device installed at a ticket gate of a station and an IC card equipped with an electronic money function, near field communication is used, for example, a reading unit of the ticket gate device. Only when an IC card exists within a short distance range of several millimeters to several tens of centimeters from each other, non-contact communication is possible between them. Such a short-range communication function is installed in various devices such as mobile phone terminals, and has begun to be used for various purposes.

  In such a short-range communication system, the distance between devices that perform non-contact communication with each other often varies relatively greatly within a very short time. As shown in FIG. 11, for example, when short-distance communication is performed between a ticket gate device installed at a ticket gate of a station and an IC card equipped with an electronic money function, it takes about 0.2 seconds. Therefore, if the output of the signal transmitted by the IC card is constant, the strength (amplitude ratio) of the signal received by the counterpart device (ticket gate device) is also as shown in FIG. Change rapidly and drastically (about 100 times).

  In such a situation, there is a high possibility that the received signal cannot be recognized correctly. Therefore, in a communication system that performs short-range communication, it is necessary to automatically adjust the signal output on the transmission side so that the intensity of the received signal does not change much even when the distance changes greatly.

  An example of a device that adjusts a signal output on a transmission side is a communication device that transmits and receives information in an UWB (Ultra Wide Band) system that transmits and receives information using an impulse train. The impulse train receiving unit and the receiving unit receive an impulse train. There is known a communication apparatus having a measuring unit that measures characteristics and a transmitting unit that transmits an impulse train at a level corresponding to a measurement result of the measuring unit (see, for example, Patent Document 1). In this communication apparatus, a transmission time slot and a reception time slot whose timings are fixed in advance are provided, and based on the strength of the signal received in the reception time slot, the signal transmitted in the transmission time slot is transmitted. The output is adjusted automatically.

JP 2003-51761 A

  However, in a conventional communication apparatus, in a communication system in which a transmission time slot and a reception time slot are fixed in advance, data transmission cannot be performed in the time slot allocated for reception, and the transmission time slot is allocated for transmission. Data cannot be received in the current time slot. For this reason, for example, when downloading a large amount of data from a server storing a large amount of data to a mobile phone terminal, each time slot cannot be used efficiently. It will reduce the speed.

  The present invention has been made in view of the above circumstances, and it is possible to prevent a decrease in effective transmission rate and to perform stable communication, a short-range communication device, a short-range communication system, and a short-range communication. It aims to provide a method.

  In order to achieve the above object, a short-range communication system according to the present invention is a short-range communication system having a first short-range communication device and a second short-range communication device that perform communication within a predetermined area. The first short-range communication device receives a propagation environment measurement signal for measuring a propagation environment transmitted from the second short-range communication device every predetermined period, and the propagation A propagation environment measurement signal transmission / reception section determination unit for determining a propagation environment measurement signal transmission / reception section, which is a section for transmitting or receiving the propagation environment measurement signal, based on the reception time of the environment measurement signal; and the propagation environment measurement signal The transmission / reception section includes a transmission frame signal generation unit that generates a transmission frame signal that does not include transmission data, and a first transmission unit that transmits the transmission frame signal generated by the transmission frame signal generation unit. The second short-range communication device has received a second transmission unit that transmits the propagation environment measurement signal at predetermined intervals, a second reception unit that receives the transmission frame signal including the transmission data, and A transmission data restoring unit that restores the transmission data by deleting data of the transmission environment measurement signal transmission / reception section from the transmission frame signal.

  With this configuration, it is possible to prevent a decrease in effective transmission rate and perform stable communication. Since it is not necessary to prepare a time slot used for transmission / reception of a propagation environment measurement signal, for example, efficient data transfer is possible in a communication system that performs asymmetric communication. In addition, by providing a section for transmitting or receiving a propagation environment measurement signal, stable communication is possible without mutual interference of signals.

  The short-range communication device of the present invention is a short-range communication device that performs communication within a predetermined region, and transmits a propagation environment measurement signal for measuring a propagation environment transmitted from another short-range communication device. A propagation environment measurement signal for determining a propagation environment measurement signal transmission / reception section, which is a section for transmitting or receiving the propagation environment measurement signal, based on a reception unit that receives each period and the reception time of the propagation environment measurement signal A transmission / reception section determination unit, a transmission frame signal generation unit that generates a transmission frame signal that does not include transmission data in the propagation environment measurement signal transmission / reception section, and a transmission that transmits the transmission frame signal generated by the transmission frame signal generation unit Part.

  With this configuration, it is possible to prevent a decrease in effective transmission rate and perform stable communication. Since it is not necessary to prepare a long time slot used for transmission / reception of a propagation environment measurement signal, efficient data transfer is possible, for example, in a communication system that performs asymmetric communication. In addition, by providing a section for transmitting or receiving a propagation environment measurement signal, stable communication is possible without mutual interference of signals.

  The short-range communication device of the present invention further includes a measurement request signal generation unit that generates a measurement request signal for requesting a propagation environment measurement signal for measuring the communication environment, and the reception unit includes: A propagation environment measurement signal transmitted from the other short-range communication device with respect to the measurement request signal is received at predetermined intervals, and the propagation environment measurement signal transmission / reception section determination unit includes a reception time of the propagation environment measurement signal and Based on the transmission time of the measurement request signal, a propagation environment measurement signal transmission / reception section that is a section for transmitting or receiving the propagation environment measurement signal is determined, and the transmission unit transmits the measurement request signal and the transmission frame. The transmission frame signal generated by the signal generation unit is transmitted.

  With this configuration, it is possible to accurately grasp at which timing a propagation environment measurement signal is received from a communication partner such as a portable terminal, and stable and efficient data transmission can be performed.

  Moreover, the short-range communication apparatus of the present invention is configured such that the transmission frame signal generation unit generates a transmission frame signal including information on the position of the propagation environment measurement signal transmission / reception section in the header.

  With this configuration, the communication partner can know at which position in the transmission frame the transmission environment measurement signal is transmitted or received, so the original transmission data is recognized based on this position information. be able to.

  The short-range communication device of the present invention further includes a region notification signal generation unit that generates a region notification signal for detecting a short-range communication device existing in the predetermined region, and the reception unit includes A data request signal for requesting the transmission data transmitted from the short-range communication device in response to an area notification signal is received, and the transmission unit transmits the area notification signal in response to the received data request signal It is configured to do.

  With this configuration, when a communication partner such as a portable terminal enters the communication range of the communication device, it is possible to perform data transmission stably and efficiently in response to various data requests requested by the communication partner. is there.

  Further, in the near field communication apparatus of the present invention, when the transmission frame signal generation unit uses the amplitude modulation method as the modulation method, the transmission frame signal generation unit sets the propagation environment measurement signal transmission / reception section to an amplitudeless state. The frame signal is generated.

  With this configuration, it is possible to construct a good communication environment without interference between the transmission device and the reception device.

  In the short-range communication apparatus of the present invention, when the transmission frame signal generation unit uses a modulation scheme other than the amplitude modulation scheme as the modulation scheme, the transmission environment measurement signal transmission / reception section is set as a null symbol. The transmission frame signal is transmitted.

  With this configuration, for example, by inserting a null symbol as a transmission signal in a signal strength decrease section, it is possible to construct a good communication environment without interference between the transmission device and the reception device.

  In the short-range communication apparatus of the present invention, the transmission frame signal generation unit generates a transmission frame signal including a header and transmission data so that the propagation environment measurement signal transmission / reception section does not overlap the header. The transmission frame signal is generated.

  With this configuration, information included in the header can be reliably notified to other short-range communication devices, and stable communication can be performed.

  Further, the short-range communication measure of the present invention includes a reception signal strength measurement unit that measures a reception signal strength of the propagation environment measurement signal received by the reception unit, and a transmission from the transmission unit based on the reception signal strength. And a transmission signal strength control unit that controls the signal strength of the transmitted signal.

  With this configuration, the signal strength of the transmission frame can be adjusted according to the signal strength of the communication signal from the communication partner, and the reception strength at the communication partner can always be adjusted to be constant. Therefore, even when the distance between the devices with the communication partner is relatively large, the strength of the received signal at the communication partner such as the portable terminal can be stabilized.

  The short-range communication device of the present invention is a short-range communication device that performs communication within a predetermined region, and includes a transmission unit that transmits a propagation environment measurement signal for measuring a propagation environment at predetermined intervals, and a transmission A receiving unit that receives a transmission frame signal including data; and the transmission environment measurement signal transmission / reception section data that is a section for transmitting or receiving the propagation environment measurement signal from the received transmission frame signal is deleted and transmitted A transmission data restoring unit that restores data.

  With this configuration, it is possible to prevent a decrease in effective transmission rate and perform stable communication. Since it is not necessary to prepare a long time slot used for transmission / reception of a propagation environment measurement signal, for example, efficient data transfer is possible even in a communication system that performs asymmetric communication. In addition, by providing a section for transmitting or receiving a propagation environment measurement signal, stable communication is possible without mutual interference of signals.

  Further, in the near field communication apparatus of the present invention, the reception unit receives the transmission frame signal including the measurement request signal and the transmission data, and the transmission unit receives the measurement request signal according to the received measurement request signal. The propagation environment measurement signal is transmitted every predetermined period.

  With this configuration, it is possible to perform data transmission stably and efficiently by receiving a transmission frame including a drop period and adjusted in signal strength based on a propagation environment measurement signal from another short-range communication device. Is possible.

  In the short-range communication device of the present invention, the transmission data restoring unit may transmit the propagation frame signal from the transmission frame signal based on information on a position of a propagation environment measurement signal transmission / reception section included in a header of the received transmission frame signal. The configuration is such that the data of the propagation environment measurement signal transmission / reception section, which is the section for transmitting or receiving the environment measurement signal, is deleted.

  With this configuration, for example, even when data with an amplitude of “00” is inserted in the lowered section, the position of the lowered section can be accurately grasped, and the data in this section can be reliably removed. The original data can be restored.

  The short-range communication apparatus of the present invention further includes a data request signal generation unit that generates a data request signal for requesting transmission data, and the reception unit receives the region notification signal, and the transmission unit Is configured to transmit the data request signal in response to the received area notification signal.

  With this configuration, when entering the communication area of a communication partner such as a server device, it is possible to transmit data stably and efficiently by requesting various data held by other short-range communication devices. is there.

  The short-range communication apparatus of the present invention is configured such that the transmission data restoration unit restores the transmission data by removing data in the propagation environment measurement signal transmission / reception section.

  With this configuration, for example, even when data with an amplitude of “00” is inserted in the lowered section, the original data can be reliably restored by removing the data in this section.

  Further, the short-range communication method of the present invention includes a step of receiving a propagation environment measurement signal for measurement of the propagation environment at predetermined intervals, and the propagation environment measurement signal based on the reception time of the propagation environment measurement signal. Determining a transmission environment measurement signal transmission / reception section, which is a section for transmission or reception, generating a transmission frame signal not including transmission data in the propagation environment measurement signal transmission / reception section, and generating the transmission frame signal And transmitting the transmission frame signal generated by the unit.

  By this method, it is possible to prevent a decrease in the effective transmission rate and perform stable communication. Since it is not necessary to prepare a long time slot used for transmission / reception of a propagation environment measurement signal, efficient data transfer is possible, for example, in a communication system that performs asymmetric communication. In addition, by providing a section for transmitting or receiving a propagation environment measurement signal, stable communication is possible without mutual interference of signals.

  The short-range communication method of the present invention includes a step of transmitting a propagation environment measurement signal for measuring a propagation environment at predetermined intervals, a step of receiving a transmission frame signal including transmission data, and the received transmission frame And deleting the data of the propagation environment measurement signal transmission / reception section, which is a section for transmitting or receiving the propagation environment measurement signal from the signal, to restore the transmission data.

  By this method, it is possible to prevent a decrease in the effective transmission rate and perform stable communication. Since it is not necessary to prepare a long time slot used for transmission / reception of a propagation environment measurement signal, for example, efficient data transfer is possible even in a communication system that performs asymmetric communication. In addition, by providing a section for transmitting or receiving a propagation environment measurement signal, stable communication is possible without mutual interference of signals.

  According to the present invention, it is possible to prevent a decrease in effective transmission rate and perform stable communication. Since it is not necessary to prepare a long time slot used for transmission / reception of a propagation environment measurement signal, for example, efficient data transfer is possible even in a communication system that performs asymmetric communication. In addition, by providing a section for transmitting or receiving a propagation environment measurement signal, stable communication is possible without mutual interference of signals.

It is a block diagram which shows an example of a structure of the short-distance communication system in the 1st Embodiment of this invention. It is a sequence diagram which shows an example of the outline of operation | movement of the near field communication system in the 1st Embodiment of this invention. (A) It is a figure which shows an example of the transmission frame signal before and behind insertion of the window area | region in the server apparatus of the 1st Embodiment of this invention. (B) It is a figure for demonstrating an example of the data transmission in the short-distance communication system of the 1st Embodiment of this invention. (C) It is a figure which shows an example of the transmission frame signal before and behind the removal of the window area | region in the portable terminal of the 1st Embodiment of this invention. It is a figure which shows an example of main operation | movement of the server apparatus in the 1st Embodiment of this invention. The figure which shows an example of operation | movement of the transmission frame signal generation part in the 1st Embodiment of this invention. It is a figure which shows an example of main operation | movement of the portable terminal in the 1st Embodiment of this invention. It is a figure which shows an example of the window area | region used in the near field communication system of the 1st Embodiment of this invention. It is a figure which shows an example of the window area | region used in the near field communication system of the 1st Embodiment of this invention. It is a figure which shows an example of a structure of the short-distance communication system in the 2nd Embodiment of this invention. It is a figure for demonstrating an example of the data transmission in the near field communication system of the 2nd Embodiment of this invention. The figure which shows an example of the relationship between time passage and the distance of short-range communication apparatuses It is a block diagram which shows an example of a structure of the short-distance communication system in the 3rd Embodiment of this invention. It is a figure for demonstrating an example of the data transmission in the 3rd short-distance communication system of this invention.

  A near field communication apparatus and a near field communication method in an embodiment of the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram showing an example of the configuration of a short-range communication system 100 according to an embodiment of the present invention. The short-range communication system 100 includes a server device 10 and a mobile terminal 20. The server device 10 has a function for data communication with the mobile terminal 20 using the short-range communication function, and for example, an automatic ticket gate device at a station can be considered. The mobile terminal 20 has a function for data communication with the server device 10 by short-range communication. For example, a mobile phone terminal equipped with electronic money or an IC card can be considered. The server device 10 is an example of a first near field communication device (or simply referred to as a near field communication device). The mobile terminal 20 is an example of a second short-range communication device (or simply referred to as a short-range communication device).

  The server device 10 includes a transmission antenna 11 and a reception antenna 12 for near field communication, a near field communication unit 13, and a control unit 14. The short-range communication unit 13 includes a transmission unit 131, a reception unit 132, and a wireless control unit 133. Further, the radio control unit 133 includes a transmission frame signal generation unit 141, a transmission amplitude control unit 142, a reception amplitude determination unit 143, an approach detection unit 144, a propagation environment measurement signal transmission / reception section determination unit 145, and a region notification signal. A generation unit 146 and a measurement request signal generation unit 147 are provided.

  The transmission unit 131 transmits data via the transmission antenna 11 using amplitude modulation.

  The receiving unit 132 receives a signal via the receiving antenna 12.

  The transmission frame signal generation unit 141 generates a transmission frame signal used when transmitting data to the mobile terminal 20 by short-range communication. The transmission frame signal generation unit 141 transmits transmission data in a propagation environment measurement signal transmission / reception section (a section for transmitting or receiving a propagation environment measurement signal) determined by a propagation environment measurement signal transmission / reception section determination unit 145 described later. Not included, a transmission frame signal including information on the position of the transmission environment measurement signal transmission / reception section is generated in the header.

  The transmission amplitude control unit 142 performs reception on the mobile terminal 20 side regardless of a change in the distance from the mobile terminal 20 based on the amplitude (or reception signal strength) of the propagation environment measurement signal determined by the reception amplitude determination unit 143. The transmission amplitude (or transmission power) is controlled so that the signal strength of the signal becomes constant. Specifically, the reception amplitude determination unit 143 determines the amplitude (or reception signal strength) of a reception signal such as a propagation environment measurement signal that the mobile terminal 20 periodically transmits, and according to the result, the transmission unit 131 The transmission amplitude is sequentially controlled.

  The approach detection unit 144 detects that the mobile terminal 20 exists within a predetermined distance from the server device 10, and the radio control unit 133 generates signals such as a measurement request signal, a region notification signal, and a transmission frame signal. To control. Specifically, first, the region notification signal generation unit 146 is caused to generate a region notification signal. When the data request signal transmitted from the mobile terminal 20 is detected, control is performed so that the measurement request signal generation unit 147 generates the measurement request signal. When the propagation environment measurement signal is detected after the measurement request signal is generated, the transmission frame signal generation unit 141 starts generation of the transmission frame signal.

  The propagation environment measurement signal transmission / reception section determination unit 145 receives, for example, the reception time of the propagation environment measurement signal (propagation environment measurement signal) transmitted from the mobile terminal 20 to the server device 10 (for example, in FIG. 3B). Based on t2 or t22), a section for transmitting or receiving a propagation environment measurement signal (the above-described propagation environment measurement signal transmission / reception section) is determined. Alternatively, the transmission time of the measurement request signal (for example, t1 or t11 in FIG. 3B), the reception time of the propagation environment measurement signal (for example, t2 or t22 in FIG. 3B), and a predetermined time required for internal processing Based on (for example, tp in FIG. 3B), the propagation environment measurement signal transmission / reception section is determined. The time or time can also be counted by the number of symbols.

  The portable terminal 20 includes a transmission antenna 21 and a reception antenna 22 for near field communication, a near field communication unit 23, and a control unit 24. The short-range communication unit 23 includes a transmission unit 231, a reception unit 232, and a wireless control unit 233. Further, the radio control unit 233 includes a propagation environment measurement signal generation unit 241, a transmission data restoration unit 242, an approach detection unit 243, and a data request signal generation unit 244.

  The transmission unit 231 transmits a signal via the transmission antenna 21 using amplitude modulation.

  The receiving unit 232 receives a signal via the receiving antenna 22.

  The propagation environment measurement signal generation unit 241 generates a predetermined propagation environment measurement signal. This propagation environment measurement signal is used for the server device 10 to control the transmission amplitude (or transmission power) so that the signal intensity when the signal is received on the mobile terminal 20 side is constant.

  The transmission data restoration unit 242 restores the header and transmission data (or payload portion) from the transmission frame signal received from the server device 10 and extracts data (or payload portion) included in the transmission frame signal. Perform the process.

  The approach detection unit 243 detects whether or not the mobile terminal 20 has entered a predetermined area where short-range communication is possible between the mobile terminal 20 and the server device 10. Specifically, a circuit for detecting a predetermined area notification signal and a measurement request signal transmitted by the server device 10 is provided. And if the area | region notification signal which the server apparatus 10 transmitted is detected, the data request signal production | generation part 244 will be made to produce | generate a data request signal. When the measurement request signal transmitted by the server device 10 is received, the propagation environment measurement signal generation unit 241 is caused to start generating the propagation environment measurement signal.

  Next, an outline of short-range communication operation between the server device 10 and the mobile terminal 20 will be described. FIG. 2 is a sequence diagram illustrating an example of an outline of the operation of the short-range communication system 100.

  First, in order to confirm whether the portable terminal 20 exists in the predetermined range in which the short distance communication of the server apparatus 10 is possible, the server apparatus 10 transmits a predetermined communication area notification signal (step S1).

  When the mobile terminal 20 enters the range in which the server device 10 can perform near field communication, the mobile terminal 20 can detect the communication area notification signal transmitted by the server device 10. When detecting the communication area notification signal, the portable terminal 20 transmits a data request signal (Req) for requesting the start of data transmission with a predetermined signal strength (step S2).

  When the server apparatus 10 receives the data request signal (Req) from the mobile terminal 20, the server apparatus 10 evaluates the reception strength (amplitude) of the received data request signal, and then sends a response signal (ACK) to the data request signal with a predetermined signal strength. (Step S3). This ACK is an example of a “measurement request signal”.

  When the mobile terminal 20 receives the response signal (ACK) from the server device 10, the mobile terminal 20 generates a predetermined signal generated by the propagation environment measurement signal generation unit 241 after a predetermined time required for internal processing (for example, tp in FIG. 3B). The propagation environment measurement signal (SG) is transmitted (step S4). Thereafter, the propagation environment measurement signal (SG) is repeatedly transmitted from the portable terminal 20 at regular time intervals until the data transmission is completed.

When the server apparatus 10 receives the first propagation environment measurement signal (SG) from the mobile terminal 20, the server apparatus 10 propagates based on the reception time of the propagation environment measurement signal (for example, t2 or t22 in FIG. 3B). A section (transmission environment measurement signal transmission / reception section) for transmitting or receiving the environment measurement signal is determined. Alternatively, the transmission time of the measurement request signal (for example, t1 or t11 in FIG. 3B), the reception time of the propagation environment measurement signal (for example, t2 or t22 in FIG. 3B), and a predetermined time required for internal processing Based on (for example, tp in FIG. 3B), the propagation environment measurement signal transmission / reception section is determined. The time or time can also be counted by the number of symbols.
Furthermore, the server apparatus 10 evaluates the reception amplitude of the received propagation environment measurement signal (SG), determines the transmission amplitude (or transmission power) of the signal transmitted from the transmission unit 131 based on the evaluation result, and performs control. To do. (Step S5).

  After the process of step S5, data transmission is started between the server device 10 and the portable terminal 20 (step S6).

  Next, a window area (or a propagation environment measurement signal transmission / reception section) used in the short-range communication system 100 will be described. FIG. 3A is a diagram illustrating an example of a transmission frame signal before and after insertion of a window area in the server device 10. FIG. 3B is a diagram for explaining an example of data transmission in the short-range communication system 100. FIG. 3C is a diagram showing an example of a transmission frame signal before and after the removal of the window area in the mobile terminal 20.

  In the short-range communication system 100, as shown in FIG. 3A, when data transmission is performed between the server device 10 and the mobile terminal 20, a propagation environment is included in a transmission frame signal transmitted by the server device 10. A special area (window area) such as a propagation environment measurement signal transmission / reception section that is a section for transmitting or receiving a measurement signal (for example, output (amplitude or power) may be suppressed) is required. Insert in position. In FIG. 3, sections W1A1, W1A2, ..., W2A1, W2A2, ..., W1B1, W1B2, ..., W2B1, W2B2, ... are examples of window areas.

  Here, since the window areas W1A1, W1A2,... Are windows provided to prevent interference with the propagation environment measurement signal (SG) transmitted by the mobile terminal 20, they are referred to as transmission windows W1A. Moreover, since window area | region W2A1, W2A2, ... is a window provided in order to prevent the interference with respect to the propagation environment measurement signal (SG) which the server apparatus 10 receives, it is called reception window W2A.

  Further, window areas W1B1, W1B2,... That appear in a frame received by the mobile terminal 20 are windows corresponding to the transmission window W1A and the reception window W2A, and are referred to as terminal windows W1B and W2B. The terminal window W1B is configured to include a predetermined range before and after the timing of transmitting the propagation environment measurement signal (SG).

  As shown in FIG. 3 (b), the transmission window W1A is at a timing preceding the position of the terminal window W1B by the propagation time. In addition, the reception window W2A comes before the terminal window W2B by the propagation time.

  Specifically, for example, the transmission window W1A has a predetermined time (for example, FIG. 3B) after the server apparatus 10 completes transmission of a response signal (ACK), which is an example of a measurement request signal (time t11). tp) or after a predetermined symbol corresponding thereto, a section corresponding to the length of the propagation environment measurement signal is provided every predetermined time interval (specifically, a transmission cycle of the propagation environment measurement signal) (or every predetermined symbol). Can be. If the transmission window W1A is set in this way, the transmission timing of the propagation environment measurement signal of the mobile terminal 10 and the transmission window W1A can be synchronized. In addition, the reception window W2A, specifically, for example, after the time of the round-trip propagation time or after the corresponding symbol (after t11-t2-tp in FIG. 3B) from the timing of the transmission window W1A ) To the length of the propagation environment measurement signal. If the transmission window W1A is set in this way, the transmission timing of the propagation environment measurement signal of the mobile terminal 10 and the transmission window W1A can be synchronized. The transmission window W1A corresponds to the length (t11-t1) of the response signal (ACK) and the predetermined time tp or the time t1 based on the time t1 instead of using the time t11 in FIG. 3B as a reference. You may make it provide every predetermined time interval after a predetermined symbol. The same applies to the reception window W2A.

  Such a transmission window and a reception window are inserted as a transmission window and a reception window in a transmission frame transmitted by the server device 10 as shown in FIG. Here, since the transmission unit 131 of the server apparatus 10 transmits a signal by amplitude modulation, when performing OOK (on-off-keying) modulation, a signal having a value of “00” is transmitted to the positions of the transmission window and the reception window. Thus, the transmission output (signal amplitude) can be cut off at the positions of the transmission window and the reception window.

  In addition, when the mobile terminal 20 receives a transmission frame signal including a transmission window and a reception window, the mobile terminal 20 receives a signal including a window area unrelated to data to be received by the transmission frame signal. As shown in c), from the received transmission frame signal, invalid data at the position of the transmission window and the reception window (terminal window in the mobile terminal 20) is deleted, and a header that is a data sequence to be received and The frame including the transmission data (or payload portion) is restored, and necessary data (or payload portion) is extracted.

  By using such a window area in the short-range communication system 100, a transmission signal (such as data requested by the portable terminal 20) transmitted by the server device 10 and a transmission signal (such as a propagation environment measurement signal) transmitted by the portable terminal. It is possible to perform stable data transmission without interfering with each other.

  In addition, communication can be performed without reducing transmission efficiency even in a communication system in which a transmission time slot and a reception time slot are not determined in advance or an asymmetric communication system in which the amount of data of transmission data and reception data is greatly different. It is possible.

  In FIG. 3B, the communication area notification signal is omitted. However, as shown in FIG. 2, the server device 10 transmits the communication area notification signal, and the mobile terminal 20 detects the communication area notification signal. Then, the data request signal (Req) may be transmitted.

  Next, main operations of the server apparatus 10 will be described. FIG. 4 is a diagram illustrating an example of main operations of the server device 10.

  In step S <b> 10, the transmission unit 131 transmits the communication area notification signal generated by the approach detection unit 144.

  In step S11, the receiving unit 132 confirms whether or not the data request signal (Req) from the mobile terminal 20 has been received. When the data request signal is received, the process proceeds to the next step S12.

  In step S12, the transmission unit 131 transmits a response signal (ACK) (an example of a measurement request signal) to the received data request signal. Also, the propagation environment measurement signal transmission / reception section determination unit 145 grasps the transmission time t1 or t11 at this time.

  In step S13, the receiving unit 132 checks whether or not the first propagation environment measurement signal (SG) from the mobile terminal 20 has been received. When the propagation environment measurement signal is received, the process proceeds to the next step S14.

  In step S14, the propagation environment measurement signal transmission / reception section determination unit 145 detects time t2 or t22 when the first propagation environment measurement signal (SG) is received. In addition, the reception amplitude determination unit 143 grasps the reception amplitude of the propagation environment measurement signal (SG). Further, the transmission amplitude control unit 142 determines the transmission amplitude (or transmission power) of a signal such as a transmission frame signal transmitted by the transmission unit 131 based on the grasped reception amplitude. Thereby, the received signal strength by the portable terminal 20 can be kept constant.

  In step S <b> 15, the propagation environment measurement signal transmission / reception section determination unit 145 calculates the propagation time td in the short-distance communication path between the server device 10 and the mobile terminal 20. Specifically, for example, time t2 at which reception of the propagation environment measurement signal (SG) is started at step S13 from time t1 at which transmission of the response signal (ACK) is started at step S12 or time t11 at which transmission of the response signal (ACK) is completed. Alternatively, the propagation time td is set to td = (t2−t1−tp) from the elapsed time until the time t22 when the reception of the propagation environment measurement signal (SG) is completed and the predetermined time tp (for example, predetermined) for internal processing. ) / 2. Alternatively, the round-trip propagation time 2 · td can be calculated as 2 · td = (t2−t1−tp).

  In step S16, the propagation environment measurement signal transmission / reception section determination unit 145 receives the first propagation environment measurement signal (SG) at time t2 or t22 and the propagation time td or 2 · td calculated in step S15. As described above, the interval between the transmission window W1A and the transmission window W2A is determined. That is, a section for transmitting or receiving a propagation environment measurement signal (a propagation environment measurement signal transmission / reception section) is determined.

  Based on the time t2 or t22 and the propagation time td or 2 · td, the times tx, tx2, tx3,... (See FIG. 3) at which the mobile terminal 20 transmits the propagation environment measurement signal (SG) are calculated. You can also For example, the time tx when the mobile terminal 20 first starts transmitting the propagation environment measurement signal (SG) corresponds to the propagation time td than the time t2 when the server device 10 starts receiving the first propagation environment measurement signal (SG). It can be estimated that it is only before. Moreover, since the portable terminal 20 transmits the propagation environment measurement signal (SG) every time a certain time (transmission environment measurement signal transmission cycle) elapses, the control unit 14 is an integer multiple of this certain time at the time tx. Can be estimated as tx2, tx3,.

  In step S17, the transmission frame signal generation unit 141 generates a transmission frame signal including a transmission window and a reception window, and the transmission unit 131 transmits data using the transmission frame signal. A method for generating a transmission frame signal will be described in detail later.

  In step S18, the wireless control unit 133 checks whether or not the data transmission is completed, and if not completed, repeats the process of step S17.

  Next, an example of the operation (step S17) at the time of frame generation by the transmission frame signal generation unit 141 will be further described. FIG. 5 is a diagram illustrating an example of the operation of the transmission frame signal generation unit 141.

  In step S20, the transmission frame signal generation unit 141 uses each transmission window W1A (W1A1, W1A2,...) And each reception window W2A (W2A1, W2A2,...) (See FIG. 3) as a propagation environment measurement signal. It is inserted at the position determined by the transmission / reception section determination unit 145. That is, each transmission window W1A and each reception window W2A are inserted into the propagation environment measurement signal transmission / reception section. Specifically, each reception window W2A is inserted into a section including a time after the transmission cycle of the propagation environment measurement signal from the time (from time t2 to time t22) when the first propagation environment measurement signal is received. Further, each transmission window W1A is inserted into a section including a time before the section of each reception window W2A by a round-trip propagation time (2.td). That is, each transmission window W1A is a time that is a round-trip propagation time (2.td) before the time after the transmission cycle of the propagation environment measurement signal from the time when the first propagation environment measurement signal is received (from time t2 to time t22). Is inserted in the section including

  As a result, for example, the second propagation environment measurement signal (SG) starts to be transmitted from the portable terminal 20 at time tx2, so that the transmission window W1A1 is a time before the terminal window W1B1 by the propagation time td, that is, It is formed in a predetermined range including a section from time tx2-td. Here, the predetermined range includes at least a time corresponding to the length of the propagation environment measurement signal from time tx2-td. Further, when the propagation time td elapses after the second propagation environment measurement signal (SG) is transmitted from the mobile terminal 20 at time tx2, the server device 10 starts receiving the propagation environment measurement signal (SG). Thus, the reception window W2A1 is formed at a position within a predetermined range including the time td2 + td after the terminal window W1B1 by the propagation time td. Here, the predetermined range includes at least a time corresponding to the length of the propagation environment measurement signal from time tx2 + td.

  In the same manner as described above, the window positions of the transmission windows W1A2,... And the reception windows W2A2,.

  In step S21, the transmission frame generation signal unit 141 creates a header including information on the propagation time td evaluated by the propagation environment measurement signal transmission / reception section determination unit 145, and this header is transmitted frame as shown in FIG. Place at the beginning of. Here, since the window position, that is, the propagation environment measurement signal transmission / reception section can be determined based on the propagation time td, the propagation time td can be referred to as information on the position of the propagation environment measurement signal transmission / reception section.

  In step S22, the transmission frame signal generation unit 141 starts allocating data to be transmitted in the transmission frame signal to be generated.

  In step S23, the transmission frame signal generation unit 141 confirms whether assignment of data to be transmitted has been completed, and if not completed, proceeds to the next step S24. Although not shown, the transmission data assigned here can be stored in the server device 10.

  In step S24, the transmission frame signal generation unit 141 checks whether or not the position on the transmission frame signal to which the current data is allocated corresponds to each window area, and if it is the position of the window area, the next step S25 is executed. If it is not the position of the window area, step S26 is executed.

  In step S25, the transmission frame signal generator 141 reduces the amplitude (or power) of the signal to be transmitted, using the information composed of the value “00” as the window area information, and the data in the transmission frame signal. Insert between. That is, at the position (timing) of each window region, a signal that is amplitude-modulated by the value “00” is transmitted, so that there is temporarily no signal. Then, the process returns to step S23, and data allocation is performed until allocation of data to be transmitted is completed.

  On the other hand, in step S26, the transmission frame signal generation unit 141 inserts the next data to be transmitted at the next position of the transmission frame signal.

  According to such a server device 10, when the mobile terminal 20 receives a signal from the server device 10 by providing a transmission window in a no-signal state in the transmission frame signal of the signal transmitted by the server device 10, A collision between the received signal and the propagation environment measurement signal (SG) can be prevented, and an error can be avoided in the data received by the mobile terminal 20 from the server device 10.

  Further, by providing a reception window in the no-signal state in the transmission frame signal of the signal transmitted by the server device 10, when the server device 10 receives the propagation environment measurement signal (SG) from the mobile terminal 20, the propagation environment Collision between the measurement signal (SG) and the signal transmitted by the server device 10 can be prevented, and errors that occur during measurement of the propagation environment can be suppressed.

  Furthermore, in order to suppress a change in reception intensity due to a sudden change in the distance between the server device 10 and the mobile terminal 20, the server device 10 repeatedly measures the reception status in a short period, and based on the result, transmits a transmission output. Can be updated frequently. In this case, by adjusting the transmission signal level (for example, transmission amplitude) according to the signal reception level of the server device 10, it is possible to eliminate the function of tracking the fluctuation of the signal reception level in the mobile terminal 20. Yes, it is possible to save power and simplify the portable terminal.

  Here, it has been described that the transmission frame signal is generated until the data transmission is completed after the transmission amplitude is determined once based on the propagation environment measurement signal. However, the propagation environment measurement signal is received every predetermined period. The transmission amplitude may be controlled each time. As a result, it is possible to perform communication with signal strength in consideration of the communication environment with the latest mobile terminal 20.

  Next, main operations of the mobile terminal 20 will be described. FIG. 6 is a diagram illustrating an example of main operations of the mobile terminal 20.

  In step S <b> 30, the approach detection unit 243 confirms whether the reception unit 232 has received the communication area notification signal from the server device 10. If reception of this communication area notification signal is detected, the process proceeds to step S31 and subsequent steps.

  In step S31, the approach detection unit 243 that has detected the reception of the communication area notification signal causes the data request signal generation unit to generate a data request signal. Then, the transmission unit 231 transmits the data request signal (Req) generated by the data request signal generation unit to the server device 10.

  In step S32, the approach detection unit 243 confirms whether or not the reception unit 232 has received a response signal (ACK) from the server device 10, which is an example of a measurement request signal. When the approach detection unit 243 detects reception of the response signal (ACK), the process proceeds to the next step S33.

  In step S33, the approach detection unit 243 that has detected the reception of the response signal (ACK) causes the propagation environment measurement signal generation unit to generate a propagation environment measurement signal at a predetermined period (or every time a predetermined time elapses). Let it begin. Then, the transmission unit 231 starts transmission of the propagation environment measurement signal (SG) generated by the propagation environment measurement signal generation unit 241 to the server device 10. The propagation environment measurement signal (SG) is repeatedly transmitted by the transmission unit 231 at a predetermined period from this point (or every time a certain time elapses).

  In step S <b> 34, the transmission data restoration unit 242 examines a signal transmitted from the server device 10 and confirms whether the frame header is received by the reception unit 232. When the header of the frame is received, the process proceeds to the next step S35.

  In step S35, the transmission data restoration unit 242 extracts information on the propagation time td from the received header, and grasps the position of each terminal window included in the received frame using the propagation time td.

  For example, the position of the terminal window W1B1 (the window area corresponding to the transmission window W1A1) is set at a certain time (that is, the propagation environment measurement signal of the propagation environment measurement signal) at the time tx when the mobile terminal 20 starts transmitting the first propagation environment measurement signal (SG). Since the transmission time tx2 (see FIG. 3) of the second propagation environment measurement signal (SG) can be determined by adding the generation or transmission cycle), a predetermined time including the length of the propagation environment measurement signal from time tx2 is determined. It can be grasped as a range.

  Further, the position of the terminal window W1B2 (the window area corresponding to the reception window W2A1) is a predetermined range after the round-trip propagation time (2 · td) between the mobile terminal 20 and the server device 10 from the position of the terminal window W1B1. I can grasp it. This can be calculated based on the propagation time td information extracted from the received header. The subsequent terminal windows W1B2, W2B2,.

  In step S36, the transmission data restoration unit 242 regards the data of the terminal window position in the received frame as invalid data and eliminates it, and restores the original transmission frame before inserting the window area. Then, the transmission data restoration unit 242 extracts data transmitted from this frame.

  In step S37, the transmission data restoration unit 242 confirms whether or not reception of all data has been completed.

  According to such a portable terminal 20, even if a transmission window signal or a reception window in a no-signal state is provided in the transmission frame signal of the signal transmitted by the server device 10, the transmission data restoration unit 242 ensures that the original transmission is performed. Frames can be restored, and stable and efficient data transmission can be realized.

  Next, another example of the window area used in the short-range communication system 100 will be described. FIG. 7 is a diagram illustrating an example of a window region used in the short-range communication system 100.

  For example, in a communication environment in which the distance between the server device 10 and the portable terminal 20 is about 10 cm at a transmission rate of about 1 Gbps, the interval between the transmission window and the reception window is a time length of about several symbols. These may be assigned as one window area without providing a boundary between the reception window and the reception window.

  In FIG. 7, the server apparatus 10 does not provide a transmission window and a reception window that are independent from each other in the transmission frame, and the transmission window and the reception window are combined into one window area WA (WA1, WA2,...). . In this case, since the mobile terminal 20 transmits the propagation environment measurement signal (SG) at a timing close to the head of the window area WB (WB1, WB2,...) In the frame received by the mobile terminal 20, the server device 10 Can receive the propagation environment measurement signal (SG) from the portable terminal 20 before the window area WA ends. In this case, a configuration in which the header does not necessarily include information on the propagation time td is also possible.

  By using such a window area in the short-range communication system 100, a transmission signal (such as data requested by the portable terminal 20) transmitted by the server device 10 and a transmission signal (such as a propagation environment measurement signal) transmitted by the portable terminal. It is possible to perform stable data transmission without interfering with each other.

  Even in a communication system in which a transmission time slot and a reception time slot are not predetermined or an asymmetric communication communication system in which the amount of transmission data and reception data is greatly different, communication can be performed without reducing transmission efficiency. Is possible.

  Next, still another example of the window area used in the short-range communication system 100 will be described. FIG. 8 is a diagram illustrating an example of a window area used in the short-range communication system 100.

  In FIG. 8, when the server apparatus 10 transmits a frame, a window area is not formed at the position of the header arranged at the head of the frame. That is, information is transmitted from the server device 10 in synchronization with the propagation environment measurement signal. In this case, the propagation environment measurement signal reception section determination unit 145 or the transmission frame signal generation unit 141 measures the propagation environment so that the position of the window area WA3 in the second transmission frame F2 and the header of the transmission frame do not overlap, for example. Based on the signal (SG) and the propagation time, the timing ts for starting transmission of the transmission frame signal F2 is adjusted.

  By using such a window area in the short-range communication system 100, data transmission can be performed stably and efficiently without interference between the header of the signal transmitted by the server device 10 and the propagation environment measurement signal (SG). It can be carried out.

  In particular, even when performing various data transmissions that require the use of a plurality of headers, it is possible to prevent recognition when reading header information.

  Although the example in which the transmission window and the reception window are combined into one window region has been described with reference to FIG. 8, the present invention can be applied even when the transmission window and the reception window are provided separately.

(Second Embodiment)
FIG. 9 is a diagram showing an example of the configuration of the short-range communication system 200 according to the second embodiment of the present invention. 9, the same components as those described in the short-range communication system 100 in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted or simplified. FIG. 10 is a diagram for explaining an example of data transmission in the short-range communication system 200.

  The short-range communication system 200 includes a server device 10B and a mobile terminal 20B.

  The server device 10B includes a transmission antenna 11 and a reception antenna 12 for near field communication, a near field communication unit 13B, and a control unit 14. The short-range communication unit 13B includes a transmission unit 131, a reception unit 132, and a radio control unit 133B. The radio control unit 133B includes a transmission frame signal generation unit 141B, a transmission amplitude control unit 142, a reception amplitude determination unit 143, an approach detection unit 144, a propagation environment measurement signal transmission / reception section determination unit 145, and a region notification signal. A generation unit 146 and a measurement request signal generation unit 147 are provided.

  The mobile terminal 20B includes a transmission antenna 21 and a reception antenna 22 for short-range communication, a short-range communication unit 23B, and a control unit 24. The short-range communication unit 23B includes a transmission unit 231, a reception unit 232, and a wireless control unit 233B. Further, the radio control unit 233B includes a propagation environment measurement signal generation unit 241, a transmission data restoration unit 242B, an approach detection unit 243, and a data request signal generation unit 244.

  The transmission frame signal generation unit 141B inserts a null frame at a position in the transmission window W1C (W1C1, W1C2,...) And the reception window W2C (W2C1, W2C2,...) Illustrated in FIG. Generate. A null symbol is a signal with reduced signal strength. The server apparatus 10B uses a transmission method in which redundancy is increased in consideration of a decrease in reliability of data in the transmission window W1C and the reception window W2C.

  The transmission data restoration unit 242B corresponds to the terminal window W1D (W1D1, W1D2,...) (Window area corresponding to the transmission window W1C) and W2D (W2D1, W2D2,...) (Corresponding to the reception window W2C shown in FIG. The demodulating process is performed in consideration of the fact that the reliability of the received data is lowered at the timing of the window area). Specifically, for example, error correction processing corresponding to the redundancy in which the data in the terminal window is increased is performed. Thereby, the original data can be reliably restored in the portable terminal 20B.

  Next, the operation of the short-range communication system 200 will be described. Although not shown, the transmission frame signal generation method and the transmission data restoration method are different from those of the short-range communication system 100. Specifically, in the short-range communication system 100, as shown in step S25 of FIG. 5, the frame generation unit 141 inserts “00” between transmission data at the position of the window region. In 200, the transmission frame signal generation unit 141B inserts a null symbol between the transmission data at the positions of the transmission window W1C and the reception window W2C. In the short-range communication system 100, as shown in step S36 of FIG. 6, the transmission data restoration unit 242B removes the window area from the received data and restores the original transmission frame. Then, the transmission data restoration unit 242B performs frame restoration in consideration of a decrease in data reliability at the positions of the terminal windows W1D and W2D.

  According to such a short-range communication system 200, an error occurring in data received by the mobile terminal 20B at the timing of the terminal window WD can be suppressed to the minimum even in a communication system other than the amplitude modulation system, and the reception window W2C Interference with the propagation environment measurement signal (SG) received by the server device 10B at the timing is suppressed, and errors that occur during the propagation environment measurement can be suppressed.

(Third embodiment)
FIG. 12 is a diagram showing an example of the configuration of a short-range communication system 300 according to the third embodiment of the present invention. 12, the same components as those described in the short-range communication system 100 in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted or simplified. FIG. 13 is a diagram for explaining an example of data transmission in the short-range communication system 300.

  The short-range communication system 300 includes a server device 10C and a mobile terminal 20C.

  The server device 10 </ b> C includes a transmission antenna 11 and a reception antenna 12 for near field communication, a near field communication unit 13 </ b> C, and a control unit 14. The short-range communication unit 13C includes a transmission unit 131, a reception unit 132, and a radio control unit 133C. The radio control unit 133C includes a transmission frame signal generation unit 141C, a transmission amplitude control unit 142, a reception amplitude determination unit 143, an approach detection unit 144, a propagation environment measurement signal transmission / reception section determination unit 145C, and a region notification signal. A generation unit 146 and a measurement request signal generation unit 147 are provided.

  The mobile terminal 20 </ b> C includes a transmission antenna 21 and a reception antenna 22 for near field communication, a near field communication unit 23 </ b> C, and a control unit 24. The short-range communication unit 23C includes a transmission unit 231, a reception unit 232, and a radio control unit 233C. Further, the radio control unit 233C includes a propagation environment measurement signal generation unit 241, a transmission data restoration unit 242C, an approach detection unit 243, and a data request signal generation unit 244.

  FIG. 13 is a diagram for explaining an example of data transmission in the short-range communication system 300. In FIG. 13, similarly to FIG. 8 of the first embodiment, when the server device 10C transmits a frame, a window region is not formed at the position of the header arranged at the head of the frame. That is, information is transmitted from the server device 10C in synchronization with the propagation environment measurement signal. In this case, the propagation environment measurement signal reception section determination unit 145C or the transmission frame signal generation unit 141C measures the propagation environment so that the position of the window area WA3 in the second transmission frame F2 and the header of the transmission frame do not overlap, for example. Based on the signal (SG) and the propagation time, the timing ts for starting transmission of the transmission frame signal F2 is adjusted.

  By using such a window area in the short-range communication system 300, data transmission can be performed stably and efficiently without interference between the header of the signal transmitted by the server apparatus 10C and the propagation environment measurement signal (SG). It can be carried out.

  In particular, it is possible to prevent erroneous recognition when reading header information even when performing various types of data transmission that require the use of a plurality of headers.

  In addition, the propagation environment measurement signal transmission / reception section determination unit 145C of the radio control unit 133C of the server device 10C in this embodiment monitors the reception time (or reception timing) t2, tr2, tr3, etc. of the propagation environment measurement signal (SG). Based on the change from the transmission cycle of the propagation environment measurement signal at this reception time (or reception timing), the value of the propagation time td is corrected every time a header is transmitted again. Then, the transmission frame signal generation unit 141C is caused to transmit the corrected value of the propagation time td, and thereafter, the transmission frame signal is generated using the corrected value of the propagation time td. Then, the transmission data restoration unit 242C of the radio control unit 233C of the mobile terminal 20C corrects the value of the propagation time td every time the header is received again, and thereafter uses this corrected value of the propagation time td to perform transmission. Restore data. By doing in this way, even if the propagation time td changes due to a change in the distance between the server device 10C and the mobile terminal 20C, it is possible to cope with this. As a premise, it is assumed that the mobile terminal 20C determines the timing of the signal to be transmitted in synchronization with the signal received from the server device 10C. That is, the timepiece of the portable terminal 20C advances according to the propagation time td being shortened, and is delayed according to the propagation time td becoming long.

  Although the example in which the transmission window and the reception window are combined into one window area has been described with reference to FIG. 13, the present invention can be applied even when the transmission window and the reception window are provided separately.

  As described above, in the short-range communication system 300 of the present embodiment, as in the short-range communication system 100, the frame generation unit 141 transmits “00” at the position of the window area as shown in step S25 in FIG. As described in the second embodiment, the transmission frame signal generation unit 141C transmits a null symbol of the transmission data at the positions of the transmission window W1C and the reception window W2C as in the second embodiment. It may be inserted between them. Further, in the short-range communication system 300 according to the present embodiment, the transmission data restoration unit 242C removes the window area from the received data as shown in step S36 in FIG. Although the description has been made on the assumption that the original transmission frame is restored, the transmission data restoration unit 242C reduces the reliability of data at the positions of the terminal windows W1D and W2D as in the second embodiment. You may make it perform the decompression | restoration of the flame | frame considered. According to such a short-range communication system 300, an error occurring in data received by the mobile terminal 20C at the timing of the terminal window WD can be suppressed to a minimum even in a communication system other than the amplitude modulation system, and the reception window W2C Interference with the propagation environment measurement signal (SG) received by the server apparatus 10C at the timing is suppressed, and errors that occur during the propagation environment measurement can be suppressed.

  INDUSTRIAL APPLICABILITY The present invention is useful as a short-range communication device, a short-range communication system, and the like that can prevent a decrease in effective transmission rate and can stably communicate.

100, 200, 300 Short-range communication system 10, 10B, 10C Server device 11 Transmission antenna 12 Reception antenna 13, 13B, 13C Short-range communication unit 14 Control unit 20, 20B, 20C Mobile terminal 21 Transmission antenna 22 Reception antenna 23, 23B , 23C Near field communication unit 24 Control unit 131 Transmission unit 132 Reception unit 133, 133B, 133C Radio control unit 141, 141C Transmission frame signal generation unit 142 Transmission amplitude control unit 143 Reception amplitude determination unit 144 Access detection unit 145, 145C Propagation environment Measurement signal transmission / reception section determination unit 146 Area notification signal generation unit 147 Measurement request signal generation unit 231 Transmission unit 232 Reception unit 233, 233B, 233C Radio control unit 241 Propagation environment measurement signal generation unit 242, 242C Transmission data restoration unit 243 Access detection 244 Data request signal generation unit W1A1, W1A2, W2A1, W2A2 Window area W1B1, W1B2, W2B1, W2B2 Window area W1C1, W1C2, W2C1, W2C2 Window area W1D1, W1D2, W2W1, W2W window , WB2, WB3 Window area

Claims (16)

A short-range communication system having a first short-range communication device and a second short-range communication device that perform communication within a predetermined area,
The first short-range communication device is:
A first receiving unit that receives a propagation environment measurement signal for measurement of a propagation environment transmitted from the second short-range communication device at predetermined intervals;
A propagation environment measurement signal transmission / reception section determination unit for determining a propagation environment measurement signal transmission / reception section, which is a section for transmitting or receiving the propagation environment measurement signal, based on the reception time of the propagation environment measurement signal;
A transmission frame signal generation unit that generates a transmission frame signal not including transmission data in the propagation environment measurement signal transmission / reception section;
A first transmission unit that transmits the transmission frame signal generated by the transmission frame signal generation unit,
The second short-range communication device is:
A second transmitter that transmits the propagation environment measurement signal at predetermined intervals;
A second receiving unit for receiving the transmission frame signal including the transmission data;
A transmission data restoration unit that restores the transmission data by deleting data of the transmission environment measurement signal transmission / reception section from the received transmission frame signal,
Near field communication system. A short-range communication device that performs communication within a predetermined area,
A receiving unit that receives a propagation environment measurement signal for measurement of a propagation environment transmitted from another short-range communication device at predetermined intervals;
A propagation environment measurement signal transmission / reception section determination unit for determining a propagation environment measurement signal transmission / reception section, which is a section for transmitting or receiving the propagation environment measurement signal, based on the reception time of the propagation environment measurement signal;
A transmission frame signal generation unit that generates a transmission frame signal not including transmission data in the propagation environment measurement signal transmission / reception section;
A transmission unit for transmitting the transmission frame signal generated by the transmission frame signal generation unit;
A near field communication device. The short-range communication device according to claim 2,
A measurement request signal generator for generating a measurement request signal for requesting a propagation environment measurement signal for measuring the communication environment;
The reception unit receives a propagation environment measurement signal transmitted from the other short-range communication device in response to the measurement request signal at predetermined intervals,
The propagation environment measurement signal transmission / reception section determination unit is a section for transmitting or receiving the propagation environment measurement signal based on the reception time of the propagation environment measurement signal and the transmission time of the measurement request signal. Determine the signal transmission / reception section,
The transmission unit transmits the measurement request signal and the transmission frame signal generated by the transmission frame signal generation unit.
Near field communication device. The short-range communication device according to claim 2,
The transmission frame signal generation unit generates a transmission frame signal including information on a position of the propagation environment measurement signal transmission / reception section in a header;
Near field communication device. The short-range communication device according to claim 2,
An area notification signal generator for generating an area notification signal for detecting a short-range communication device existing in the predetermined area;
The receiving unit receives a data request signal for requesting the transmission data transmitted from the other short-range communication device in response to the area notification signal;
The transmitter transmits the region notification signal in response to the received data request signal;
Near field communication device. The short-range communication device according to claim 2,
When the short-range communication apparatus uses an amplitude modulation method as a modulation method, the transmission frame signal generation unit is a short-range communication device that generates the transmission frame signal in which the propagation environment measurement signal transmission / reception section has no amplitude state. The short-range communication device according to claim 2,
The transmission frame signal generation unit transmits the transmission frame signal using the propagation environment measurement signal transmission / reception section as a null symbol when the short-range communication device uses a modulation scheme other than the amplitude modulation scheme as a modulation scheme. . The short-range communication device according to claim 2,
The transmission frame signal generation unit generates a transmission frame signal including a header and transmission data, and generates a transmission frame signal so that the propagation environment measurement signal transmission / reception section does not overlap the header,
Near field communication device. The short-range communication device according to claim 2,
A received signal strength measuring unit for measuring a received signal strength of the propagation environment measuring signal received by the receiving unit;
A transmission signal strength control unit that controls a signal strength of a signal transmitted from the transmission unit based on the received signal strength;
Near field communication device.
A short-range communication device that performs communication within a predetermined area,
A transmitter for transmitting a propagation environment measurement signal for measurement of the propagation environment at predetermined intervals;
A receiving unit for receiving a transmission frame signal including transmission data;
A transmission data restoration unit that restores the transmission data by deleting data of a propagation environment measurement signal transmission / reception section, which is a section for transmitting or receiving the propagation environment measurement signal from the received transmission frame signal,
Near field communication device. The short-range communication device according to claim 10,
The receiving unit receives the transmission frame signal including the measurement request signal and the transmission data;
The transmission unit transmits the propagation environment measurement signal at predetermined intervals according to the received measurement request signal.
Near field communication device. The short-range communication device according to claim 10,
The transmission data restoration unit is configured to transmit or receive the propagation environment measurement signal from the transmission frame signal based on information on a position of the propagation environment measurement signal transmission / reception section included in the header of the received transmission frame signal. Delete the data of the transmission environment measurement signal transmission / reception section that is the section,
Near field communication device. The short-range communication device according to claim 10,
A data request signal generator for generating a data request signal for requesting transmission data;
The receiving unit receives the region notification signal,
The transmitter transmits the data request signal in response to the received region notification signal;
Near field communication device. The short-range communication device according to claim 10,
The transmission data restoration unit restores the transmission data by removing data in the transmission environment measurement signal transmission / reception section. A short-range communication method for performing communication within a predetermined area,
Receiving a propagation environment measurement signal for measurement of the propagation environment at predetermined intervals;
Determining a propagation environment measurement signal transmission / reception section, which is a section for transmitting or receiving the propagation environment measurement signal, based on the reception time of the propagation environment measurement signal;
Generating a transmission frame signal not including transmission data in the propagation environment measurement signal transmission / reception section;
A step of transmitting the transmission frame signal generated by the transmission frame signal generation unit; A short-range communication method for performing communication within a predetermined area,
Transmitting a propagation environment measurement signal for measurement of the propagation environment at predetermined intervals;
Receiving a transmission frame signal including transmission data;
Deleting the transmission environment measurement signal transmission / reception section data that is a section for transmitting or receiving the propagation environment measurement signal from the received transmission frame signal, and restoring the transmission data;
A near field communication method.

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