JP2003169367A - Wireless communication device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To restrict communication of a wireless communication device in a use restricted area where an existing wireless communication system exists. [MEANS FOR SOLVING PROBLEMS] A wireless communication device capable of performing communication in a predetermined frequency band, the communication of another wireless communication system performing wireless communication only in a wireless communication permitted area in which wireless communication using the predetermined frequency band is permitted. A receiving unit that receives a signal and confirms the presence of another wireless communication system based on the received signal; and a position determining unit that determines whether the position of the wireless communication device is within a wireless communication permission area. In addition, while confirming the existence of another wireless communication system, the wireless communication device enters the wireless communication enabled state only when it is determined that the wireless communication device is located in the wireless communication permitted area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless communication technique for performing communication in a predetermined frequency band.

[0002]

2. Description of the Related Art With the expansion of wireless communication services represented by cellular mobile phones and the increase of Internet users,
There is an increasing demand for a transmission channel (frequency) for wirelessly performing broadband data communication such as broadband Internet communication. In response to this, applications have been limited in the past, and so-called “opening of frequency bands”, which is generally open to frequency bands that have been limited to such specific applications or only to specific users, has been advanced. The condition for use is that "a newly entered system does not interfere with an existing system that has been using the frequency band for a long time." To clear this condition,
Research on radio wave interference avoidance technology and wireless communication system coexistence methods has become popular.

Microwaves in the GHz band and above, which are characterized by strong directivity and large attenuation in the atmosphere, can easily control the size of the service area by limiting the transmission output. it can. Therefore, an unspecified number of unnecessary ISM band of possible frequency use license use (I ndustri
standard ST of al S cientific M edical wireless communication system using a frequency band of the B and) (for example, ARIB (of Radio Industries and Businesses)
The use of a wireless LAN using a low power data communication system such as D-T70 or ISO / IEC88012-11 is under study.

[0004]

However, in the service area of the existing system and its vicinity, the use of the newly entered system is considered to be particularly severely restricted. For example, in the vicinity of areas where backbone trunk lines such as telephone networks are provided, or in areas where microwave lines are used by communication carriers as backup lines in the event of a disaster such as a disaster. Is a so-called restricted area.

When a wireless LAN using wireless communication devices using a wireless communication system newly permitted to use is constructed within the above-mentioned restricted area and using the frequency band used for the above-mentioned line, it becomes a microwave line. It may cause a great deal of damage.

Therefore, it is considered that the use of a wireless communication device using a wireless communication system that uses the same frequency band as the microwave line near the microwave line is not permitted. Thus, it is necessary to limit the configuration of a wireless LAN by another wireless communication system in a specific area where an existing wireless communication system exists in a certain frequency band.

Generally, when it is assumed that a plurality of radio communication systems use the same frequency band, in order to prevent a decrease in frequency utilization efficiency due to respective radio wave interference,
Interference avoidance and coexistence methods based on carrier sense are specified.

The carrier sense means that the wireless communication device measures the electric field strength (signal strength) of the received signal at the frequency at which wireless communication is about to be performed. For example, when the electric field strength is equal to or higher than a predetermined threshold value, it is determined that the wireless communication system that should avoid interference is performing the transmission, and the transmission of the radio wave is stopped. If the electric field strength is less than the predetermined threshold value, it is determined that the frequency is vacant and transmission is performed.

By the way, in the wireless communication system,
Since the frequencies that can be effectively used are limited, the same frequency band may be used by a plurality of wireless communication systems.
In a wireless communication system of the base station centralized control system, base stations are fixedly arranged so that a service area is not overlapped with a specific area whose use is restricted like a cellular system of mobile communication such as a mobile phone. As a result, it is possible to avoid interference by the mobile radio terminal with respect to the existing radio communication system.

However, mobile wireless terminals using a distributed control type wireless communication system can establish an ad hoc (temporary) wireless LAN with respect to a position (location), and each terminal can perform independent distributed control in which it performs its own control. In the operating mode to be performed, transmission is possible anywhere.

Further, even in a centralized control type wireless communication system having a base station, it cannot be guaranteed that the base station is outside the use restricted area if the base station is not fixedly arranged. In such a case, the above-mentioned carrier sense alone is not sufficient as a method for avoiding interference that limits transmission within the usage-restricted area.

That is, the carrier sense can only determine whether or not some kind of wireless communication is performed in a specific time zone, and cannot determine whether or not the terminal itself exists in a specific area. is there. Therefore, there is a possibility that the device will transmit itself even though it is within the restricted area. For example, even if the target wireless communication system is temporarily not communicating, or even if the wireless communication system targeted for carrier sense is communicating, carrier sensing may not be performed correctly due to the effects of topography, etc. The situation of is applicable. Incidentally, JP-A-11-
Japanese Patent No. 215562 discloses a technique for restricting wireless communication within a specific area. The technique described in the above publication will be described with reference to FIG.

As shown in FIG. 11, the use-restricted area 11
The use restriction device 11-2 is arranged in -1. The use control device 11-2 transmits a use control signal 11-3 in the use control area 11-1. The mobile terminals 11-4 and 11-5 are provided with a receiving means and a decoding means for the use control signal 11-3 transmitted by the use control device 11-2.

For example, when the movable second terminal 11-5 that wirelessly communicates with the first terminal 11-4 enters the usage restriction area, the usage restriction signal 11- transmitted by the usage restriction device 11-2. Receive 3 When the usage control signal 11-3 is received, the second terminal 11-5 stops the transmission. In this way, it becomes possible to restrict the use of the wireless communication device in the restricted use area.

According to the above technique, it is considered possible to limit the transmission, but there is a problem that it is necessary to newly install a use control device on the existing line side. In addition, an excessive burden occurs such as securing a frequency for transmitting the usage control signal. The present invention is to provide a technique capable of more easily and reliably restricting the use of a wireless communication device in a use restricted area.

[0016]

According to one aspect of the present invention, there is provided a wireless communication device capable of communicating in a predetermined frequency band, wherein wireless communication utilizing the predetermined frequency band is permitted. Confirmation means for receiving a communication signal of another wireless communication system that performs wireless communication only within the permission area, and confirming the presence of the other wireless communication system based on the received signal, and the position of the wireless communication device is the above-mentioned. A position determining unit that determines whether or not the wireless communication device is within the wireless communication permission region, confirms the existence of the other wireless communication system, and determines that the wireless communication device is located within the wireless communication permission region. There is provided a wireless communication device in which wireless communication is possible only in the wireless communication device. According to the above wireless communication device, since wireless communication is possible only within the same area as the other wireless communication system whose existence has been confirmed, it is possible to ensure the use restriction of the wireless communication device.

The position determining means compares the received signal strength measuring means for measuring the strength of the received signal with the signal strength determining means for comparing the strength of the received signal with a preset threshold value of the signal strength. It is preferable to have and. Depending on whether the received signal strength is equal to or more than the threshold value,
It is possible to determine whether or not the wireless communication device is within the communication permission area.

The position determining means includes a received signal-to-noise ratio calculating means for calculating a signal-to-noise ratio based on the received signal, and the signal-to-noise ratio and a preset threshold value of the signal-to-noise ratio. It is preferable to have a received signal-to-noise ratio determining means for comparing It is possible to determine whether or not the wireless communication device exists within the communication permission area depending on whether or not the received signal-to-noise ratio is equal to or higher than the preset threshold value of the signal-to-noise ratio.

The position determining means calculates a bit error rate based on the received signal, and an error rate comparing the bit error rate with a preset threshold value of the bit error rate. It is preferable to have a judging means. It is possible to determine whether or not the wireless communication device exists within the communication permission area depending on whether or not the received signal error rate is equal to or more than the set threshold value of the bit error rate.

The confirmation means includes control information extraction means for extracting control information contained in the received signal, and control information comparison means for comparing the extracted control information with preset control information. Is preferred. The control information is used as a criterion for the confirmation means, and it is determined whether or not the signal of the other wireless communication system is received depending on whether or not the control information is the same as the preset control information.

The checking means has a preamble signal extracting means for extracting a preamble signal included in the received signal, and a preamble comparing means for comparing the extracted preamble signal with a preset preamble signal pattern. Is preferred. Using the preamble signal of the received signal as a criterion of the confirmation means, when the preamble signal is a preset preamble pattern, the other wireless communication system uses a signal of a wireless LAN configured in a communication permission area. Determined as received.

The confirmation means includes control information extraction means for extracting control information included in the received signal, control information comparison means for comparing the extracted control information with preset control information, and It is preferable to have preamble signal extraction means for extracting a preamble signal included in the received signal, and preamble comparison means for comparing the extracted preamble signal with a preset preamble signal pattern.

In determining whether or not the signal of the other wireless communication system is received, both the control information of the received signal and the preamble signal are used as the determination reference to make the determination more reliably. You can For example, when a preamble signal is used as a criterion of the confirmation means and the preamble signal has a preset preamble pattern, it can be determined that a signal of the other wireless communication system is received.

The wireless communication device can use a plurality of frequency channels in the predetermined frequency band, detects a frequency channel being used by the other wireless communication system, and detects the frequency channel being used. It is preferable to perform communication by switching to an empty frequency channel that is a frequency channel other than the frequency channel.

The wireless communication device is capable of utilizing a plurality of frequency channels in the predetermined frequency band, calculates timings for receiving signals necessary for the confirmation means and the position determination means, and calculates the calculated timings. It is preferable to include channel switching timing control means for switching from a frequency channel currently in use to a frequency channel capable of receiving the necessary signal in accordance with the timing. By receiving a signal of the other wireless communication system while performing communication on an empty frequency channel that is not used by the other wireless communication system, for example, position determination can be performed by the same antenna or wireless receiving unit. .

According to another aspect of the present invention, there is provided a first wireless communication system for performing wireless communication only within a wireless communication permission area where wireless communication using a predetermined frequency band is permitted,
A second wireless communication system including a wireless communication device that performs communication in the predetermined frequency band, the communication signal being received by the first wireless communication system, and the first wireless communication based on the received signal. A second wireless communication system including a wireless communication device including a confirmation unit that confirms the existence of the system and a position determination unit that determines whether or not the position of the wireless communication device is within the wireless communication permission area. A wireless communication system having the same is provided.

The wireless communication device included in the second wireless communication system confirms the existence of the first wireless communication system, and only when it determines that the wireless communication device is located within the wireless communication permission area. Performs transmission for wireless communication. According to another aspect of the present invention, first wireless communication is performed only within a wireless communication permitted area in which wireless communication is permitted.
A wireless communication method in a second wireless communication system for performing communication in the same frequency band as a predetermined frequency band used by the wireless communication system, comprising: (a) receiving and receiving a communication signal of the first wireless communication system. The first based on the signal
Confirming the existence of the wireless communication system of
(B) determining whether or not the position of the wireless communication device is within the wireless communication permission area, and (c) confirming the existence of the first wireless communication system in step (a), and And a step of performing wireless communication only when it is determined to be located within the wireless communication permission area in the step (b).

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION The inventor of the present invention is a wireless communication system for performing communication outside a restricted use area in order to determine whether or not a wireless communication device to be used is outside a specific area where usage is restricted, that is, a restricted use area. Then, he came up with the idea of using a wireless communication system including a base station fixedly arranged outside the restricted area. For example, a control signal transmitted by a base station included in another wireless LAN that forms a service area only outside the restricted area is used.

A means for receiving a control signal of another wireless LAN is added to a mobile wireless terminal using a distributed control type wireless communication system. When the control signal of another wireless LAN is received, it is assumed that the self (mobile wireless terminal) is located within the service area (outside the use restricted area), and it is determined that the wireless communication is possible. That is, communication is not performed by determining that wireless communication is not being performed as in the method based on carrier sense, but communication is performed only when it is confirmed that specific wireless communication is being performed. Of. As a result, it is possible to limit the use of the wireless communication device in the use restricted area (specific area). An environment on which the wireless communication device according to the embodiment of the present invention is based on the above principle will be described with reference to FIG. FIG. 2 is a schematic diagram for explaining the environment on which the present invention is based.

As shown in FIG. 2, it is assumed that the use restricted area 2-1 exists in the area to be considered. In the restricted use area 2-1, for example, an existing wireless communication system using a predetermined frequency band exists. The use of wireless communication devices using other wireless communication systems newly permitted to use the frequency band is restricted.

The wireless LANs 2-2, 2-3 and 2-4 are
Base station 2-2 fixedly arranged like a cellular system
Due to 1, 2-3-1, and 2-4-1, the use restricted area 2-1 and the wireless LAN service area (defined within a predetermined range centered on the base station in FIG. 2) do not overlap each other. It is generally configured as follows. For example, the base station of each wireless LAN is a WAN ( W
It is connected by wire or the like ide A rea N etwork) 2-5 and the optical fiber 2-6. Each home,
Terminals located in the office 2-8 and base stations 2-2-1,
FWA ( F that connects wirelessly between 2-3-1 and 2-4-1
ixed W ireless A ccess) configuration of the like can be considered.

The wireless communication technique according to this embodiment is shown in FIG.
In an environment such as that shown in, for example, a notebook PC (personal computer) or a PDA (P ersonal D a
A mobile communication terminal such as a mobile communication device (ta A stance) is directly connected by wireless communication.
c) The use of a wireless communication terminal equipped with a wireless communication card for configuring the wireless LAN is restricted.

First, a radio communication technique according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 3 to 9. Please also refer to FIG. 2 as appropriate.

FIG. 1 is a diagram showing a schematic configuration of a wireless communication system according to the first embodiment of the present invention. Figure 3
(A) shows the first to fourth radio waves in a predetermined frequency band.
FIG. 3B is a diagram showing a principle of dividing and using the four frequency channels up to, and FIG. 3B is a chart diagram showing a usage example of the four frequency channels from the first to the fourth. FIG. 4 is a diagram showing an example of using frequencies in a centralized control wireless communication system, FIG. 4 (a) is a diagram showing an example of a data structure for communication, and FIG. 4 (b) is a time chart of a frequency channel. It is an example of using the area. FIG. 5 is a diagram showing a frequency usage example in a distributed control wireless communication system, which is a time domain usage example of a frequency channel. FIG. 6 is a functional block diagram of the entire wireless communication device according to the first embodiment of the present invention. FIG. 7 is a functional block diagram showing the structure of the wireless transmission / reception unit in FIG. FIG. 8 is a flowchart showing the operation of the distributed control type wireless communication device in the wireless transmission system according to the present embodiment. Figure 9
FIG. 9 is a diagram for explaining a confirmation method by a confirmation means in the wireless communication device according to the present embodiment, FIG. 9 (a) is a diagram showing a data structure of a preamble, and FIG. 9 (b) is a diagram.
It is a conceptual diagram for demonstrating the identification method by a preamble.

As shown in FIG. 1, a first relay base station 1-1 and a second relay base station 1-2 are included in the area to be considered.
And a wireless relay line 1 formed by the third relay base station 1-3. The wireless relay line 1 is a medium-to-long-distance data transmission system that utilizes microwave and millimeter wave frequency bands and uses a directional antenna and has a large transmission power.
For example, it is a medium-to-long distance wireless relay line such as an ISDN telephone network or a backup line of a wired line. A use-restricted area (2-1) is defined along the wireless relay line 1 in an area as shown in FIG. 2, for example.

A wireless communication system 1'using a centralized control system typified by ARIB STD-T70 is provided in an area that does not overlap with the use restricted area (2-1: FIG. 2). First wireless communication system (LAN) 1-
7 includes, for example, a first base station 1-4, a first terminal 1-5, and a second terminal 1-6. Wireless communication system (LAN) 1-
Reference numeral 7 divides the same frequency band as the frequency band of the signal used in the radio relay line 1 into a plurality of channels for use.

The use of the frequency band will be described with reference to FIG. The wireless relay line 1 (FIG. 1) is shown in FIG.
As shown in, wireless communication is performed using a frequency band 3-1 having a 100 MHz width of, for example, 5.15 to 5.25 GHz. The first wireless communication system (LAN) 1-7 is
For example, the frequency band 3-1 is designated by reference numerals 3-2, 3-3, 3
5.17 GHz, 5.19 GH like -4 and 3-5
Centering the respective frequencies of z, 5.21 GHz and 5.23 GHz, the respective channels are divided into a plurality of frequency channels in consideration of the respective interferences. The respective channels are referred to as a first frequency channel 3-6, a second frequency channel 3-7, a third frequency channel 3-8 and a fourth frequency channel 3-9.

As shown in FIG. 3 (b), one of the first to fourth frequency channels is used to allocate time for data communication (time domain allocation) to the time axis. And perform wireless communication at the allotted time. For example, the first base station 1-4 and the first terminal 1 of FIG.
-5 uses the first frequency channel 3-6. The time domain is divided into units called frames on the time axis. At the beginning of the frame, the first base station 1-
10 (FIG. 1) transmits control information 3-6-1 indicating allocation of the time domain in the frame and the like. Then, in the designated time domain within the frame, the first base station and the first terminal perform data 3-
6-2 and the control signal 3-6-3 of the first terminal are transmitted.
During this time, the other frequency channels 3-7 to 3-9 are free. Therefore, another wireless communication device can use these idle channels.

As shown in FIG. 1, the second wireless LAN 1-
10 includes a third terminal 1-8 and a fourth terminal 1-9. The second wireless LAN 1-10 is IEEE802.1
1 is a distributed control type wireless communication system. Regarding the usage method of frequency band, the second wireless LA
N1-10 is the same as in the case of the first wireless LAN 1-7 shown in FIG.

As shown in FIG. 1, the second wireless LAN 1-
Reference numeral 10 denotes a wireless L configured by fixedly arranged base stations.
Note P equipped with wireless LAN card etc. instead of AN
Temporary (A for communication between C or PDA)
d-hoc) wireless LAN.

That is, the service area of the first wireless LAN 1-7 is fixed, whereas the second wireless LA 1-7 is fixed.
N1-10 service area is "anytime, anywhere"
It is a form. In the wireless communication system according to the present embodiment, it is possible to prevent the communication communication device (terminal) that performs such wireless communication from being used in the use restricted area (2-1: FIG. 2).

As shown in FIG. 4, the first wireless LAN 1-
7, communication is performed in units of periodic frames 4-1.
One frame 4-1 includes a Down-link 4-, which includes control information 4-2 for controlling communication and transmission / reception data.
3 and Up-link 4-4 are included. For example,
Data 4-5-1 is transmitted and received in the time domain 4-5, and data 4-6-1 is transmitted and received in the time domain 4-6.

The control information 4-2 includes a preamble 4-7 and a data payload (1 to N) 4-8. Based on the control information 4-2, the base station 1-4 of the first wireless LAN 1-7 controls the control information including the preamble signal 4-7 for frame synchronization and the band allocation for transmission / reception in the frame 4-1. Data (data payload) 4-8 is periodically transmitted.

The base station 1-4 transmits the data 4-5-1 in the time area 4-5 designated by the control information 4-2, and the terminals 1-5 and 1-6 transmit the data 4-5-1. 5-1
To receive. The terminals 1-5 and 1-6 use the data 4-6-1 in the time area 4-6 designated by the control information 4-2.
And the base station 1-10 transmits the transmitted data 4-6-
Receive 1 First two-way wireless communication by these
Wireless LAN 1-7.

The third terminal 1-8 and the fourth terminal 1-9 use the distributed control type wireless communication system to perform the second wireless LA.
Configure N1-10. The third terminal 1-8 is the fourth terminal 1-
When it is desired to transmit data to 9, the RTS signal 5-1 of the data transmission request signal is transmitted as shown in FIG. When the fourth terminal 1-9 can normally receive the RTS signal 5-1, the fourth terminal 1-9 transmits the CTS signal 5-2 notifying that the data reception preparation is completed.

The third terminal 1-8 receives the CTS signal 5-2 and transmits the data signal 5-3. The fourth terminal 1-9
The third terminal 1-8 is notified by the ACK signal 5-4 that the data signal 5-3 has been normally received. 4th terminal 1
By performing the same operation from -9 to the third terminal 1-9, bidirectional wireless communication can be performed.

FIG. 6 is a functional block diagram of a wireless communication device (terminal) according to this embodiment. FIG. 7 is a detailed functional block diagram of the wireless transmission / reception unit of FIG.

FIG. 8 is a flow chart showing the operation of the wireless communication apparatus according to this embodiment, and the wireless communication technology according to the first embodiment of the present invention will be described in detail below with reference to FIGS. 6 and 7.

As shown in FIG. 6, the radio communication apparatus according to this embodiment has an antenna AT and a radio transmission / reception section 6-1.
A demodulation circuit 6-2, a wireless data extraction unit 6-4, and a received data storage unit 6-6. Further, the wireless communication device includes a bus control circuit 6-10, a transmission data storage unit 6-7, a wireless data generation unit 6-5, and a modulation circuit 6-3.
And have. In addition, it has a communication control unit 6-8 and a timing information generation circuit 6-9.

The wireless transmission / reception section 6-1 transmits / receives signals via the antenna AT. The signal received by the wireless transmission / reception unit 6-1 is demodulated by the demodulation circuit 6-2. The wireless data extraction unit 6-4 extracts data from the demodulated signal. The extracted data is stored in the received data storage unit 6-
The data is stored as received data by 6. The received data is
The bus control circuit 6-10 sends the data to a device having a data transmission / reception function, such as a personal computer PC.

On the other hand, transmission data from an external device such as a personal computer PC is stored in the transmission data storage unit 6-.
Temporarily saved in 7. The wireless data generation unit 6-5 generates wireless data based on the transmission data. The wireless data modulated by the modulation circuit 6-3 is sent to the wireless transmission / reception unit 6-1 and transmitted as a signal radio wave.

In the above example, the wireless terminal is used by inserting the wireless communication device for wireless LAN into the PC card slot or the LAN port of the notebook PC, but according to the present embodiment. The wireless communication device is not limited to this form, and includes other forms such as a built-in PDA or a built-in notebook PC having a wireless function.

The wireless communication device further controls the entire device including the above-mentioned respective functional parts, and has a communication control part 6-8 having a function of controlling various operations shown in the flow chart shown in FIG. 8, and timing information. And a timing information generation circuit 6-9 for generating.

FIG. 7 is a functional block diagram showing a more detailed structure of the wireless transmission / reception unit 6-1. Wireless transceiver 6-1
Has a wireless transmission / reception means and a communicability determination means. The wireless transmission / reception means includes an antenna 6-11, an antenna duplexer 6-12, a wireless reception unit 6-13, a received power detection unit 6-18, an A / D conversion unit 6-15, and a preamble detection unit 6 -17. Further, the wireless transmission / reception means has a D / A conversion unit 6-16 and a wireless transmission unit 6-14. The antenna duplexer 6-12 is the antenna 6-
11 is connected. The output from the modulation circuit 6-3 (FIG. 6) is input to the D / A conversion unit 6-16, and the antenna duplexer 6
A signal is transmitted from antenna 6-11 to -12.

Antenna 6-11 and antenna duplexer 6-
The signal received by the wireless reception unit 6-13 via 12 is transmitted to the A / D conversion unit 6-15 and the preamble detection unit 6-.
It is output to the communication control unit 6-8 via 17 and. Also,
The signal received by the wireless reception unit 6-13 is output to the communication control unit 6-8 via the reception power detection unit 6-18.

The communicability determining means includes a first wireless LAN preamble comparing section 7-1, a first wireless LAN demodulating circuit 7-2, and a first wireless LAN received signal strength comparing section 7-3.
And have. Furthermore, the communicability determining means includes the first wireless LAN wireless data extraction unit 7-4 and the first wireless LAN.
Control information confirmation unit 7-5, and BER for the first wireless LAN
It has a C / N calculator 7-6 and a communicability determination controller 7-7.

The output signal from the preamble detection unit 6-17 is input to the first wireless LAN preamble comparison unit 7-1. The output signal from the A / D converter 6-15 is the first
It is input to the wireless LAN demodulation circuit 7-2. The output signals from the received power detectors 6-18 are input to the first wireless LAN received signal strength comparator 7-3. The output signal from the first wireless LAN demodulation circuit 7-2 is output to the first wireless LAN control information confirmation unit 7-5 and the first wireless LAN BER / C / N calculation unit 7-6.

First wireless LAN preamble comparison section 7-
1, first wireless LAN reception signal strength comparison unit 7-3, first
Wireless LAN control information confirmation unit 7-5 and first wireless LA
The output signal from the N BER / C / N calculation unit 7-6 is input to the communicability determination control unit 7-7. Data is exchanged between the communicability determination control unit 7-7 and the communication control unit 6-8.

The radio communication technique according to the present embodiment will be described below centering on the method of determining whether communication is possible. When the wireless communication is started, the communication control unit 6-8 instructs the communication availability determination control unit 7-7 to execute another wireless LAN (first
Wireless LAN 1-7 of FIG. 1) (FIG. 1) is instructed to perform communication availability determination including presence confirmation and terminal position determination.

First, carrier sense processing 8-1 is performed.
In the carrier sense processing 8-1, the wireless reception unit 6-
13 starts the receiving operation on the designated frequency channel. When the reception operation is started, the signal (radio wave) received by the wireless reception unit 6-13 is converted into a reception signal strength signal (RSSI signal) by the reception power detection unit 6-18.

First wireless LAN received signal strength comparison unit 7-
3 determines whether or not a certain criterion (a preset threshold value) is exceeded. If it exceeds the threshold, it is considered that there is a received radio wave, and if it does not exceed the threshold, it is considered that there is no received radio wave. In step 8-2, the communication availability determination control unit 7-7 is notified of the determination result of the presence or absence of the received radio wave.

In step 8-2, if there is no received radio wave, it is determined that the communication is impossible and communication is not started (end). In addition, in the carrier sense process in a general wireless communication device, when there is no received radio wave,
Although it is determined that the channel is an empty channel and transmission is started, the wireless communication device according to the present embodiment cannot determine the communication permission area by itself. As a result, it is possible to perform processing such as notifying the user that communication is impossible or performing carrier sense processing for a certain period of time until the received radio wave is confirmed.

If the received radio wave is confirmed in step 8-2, a wireless LAN confirmation process 8-3 is performed. In the wireless LAN confirmation process 8-3, first, the received signal is A
After the A / D conversion is performed by the / D conversion unit 6-15, it is sent to the preamble detection unit 6-17 and the pattern of the preamble signal is extracted. First wireless LAN preamble comparison unit 7-
1 determines whether the pattern of the preamble signal matches the preamble pattern registered in advance and specific to the first wireless LAN.

Here, the preamble will be described with reference to FIGS. 9 (a) and 9 (b). As shown in FIG. 9 (a),
In a wireless communication system used for a wireless LAN, a transmission signal is generally composed of a preamble part 10-1 and a data payload part 10-2 for storing data to be actually sent.

The preamble section 10-1 has a signal pattern unique to the system. For example ARIB STD
-T70 defines a control information preamble 10-3, a terminal data transmission preamble 10-4, and a base station data transmission preamble 10-5.

The control information preamble 10-3 is a preamble for a control information signal transmitted by the base station for frame synchronization and frame configuration information notification. The terminal data transmission preamble 10-4 is used when each terminal transmits data to the base station. The base station data transmission preamble 10-5 is used when the base station transmits data to the terminal.

The portions indicated by the letters A, B and C actually have specific signal waveforms. For example, A has a signal waveform indicated by reference numeral 10-6, as shown in FIG. By comparing the pattern 10-7 obtained by A / D converting this signal waveform with the received signal, the received signal is identified and processed such as signal synchronization.

A preamble for identifying that the first wireless LAN is a signal sequence indicated by reference numeral 10-3 in FIG. 10A and is a signal sequence transmitted from a fixedly arranged base station. If the first wireless LA
In the N preamble comparison unit 7-1 (FIG. 7), it is possible to confirm the existence of the first wireless LAN by comparing whether the preamble patterns match.

By the way, ISO / IEC8802-1
The CSMA / CA wireless communication system standardized by 1: 1999 and the like is basically a system that constitutes a temporary (Ad-hoc) wireless LAN in which terminals directly communicate with each other. It also has a mechanism to communicate only between the base station (access point) and the terminal.

Even in such a case, it is stipulated that the base station is fixedly arranged so that the specific area (usage-restricted area) and the service area do not overlap, and that the base station is a fixedly arranged base station. Stipulates that a control signal (called a beacon signal) including control information for notifying the terminal (mobile station) is periodically transmitted, and that the terminal does not transmit at all until it receives the beacon signal. By doing so, it is possible to give the same role as the first wireless LAN 1-7 using the wireless communication system of the base station centralized control method.

By the way, when such a system is the first wireless LAN 1-7, the base station is originally treated as a terminal, so that the preamble patterns of the terminal and the base station are the same. Therefore, the existence of other wireless LAN cannot be confirmed only by the preamble pattern.

Therefore, in order to cope with the above case, the A / D converted signal is demodulated by the first wireless LAN demodulation circuit 7-2, and the first wireless LAN wireless data extraction unit is further used. In 7-4, control information is extracted by decoding such as error correction code.

The first wireless LAN control information confirmation section 7-5 determines whether or not the control information matches the registered control information. The control information in this case is, for example, STD-T70.
Then, the ID is an identification ID indicating that the wireless LAN created by the base station is a public base station fixedly arranged. IEEE
In 802.11, the base station itself is the first wireless LA
It is an ID for identification indicating that it is a control signal (beacon signal) for notifying that it is a base station forming N.

Returning to the flowchart (FIG. 8), if it is confirmed in step 8-4 that the first wireless LAN does not overlap the restricted area and the service area, the terminal position determination processing 8-5 is started. If the presence of the first wireless LAN cannot be confirmed, communication is not started.

In the terminal position determination processing 8-5, the first wireless L
In the AN reception strength comparison unit 7-3, the reception power strength is compared with a predetermined threshold value to determine whether or not the reception power strength exceeds a predetermined reception signal strength threshold value. To do. This comparison result is used as the communicability determination control unit 7
In step -7, the number of times the reception strength is equal to or higher than the threshold value is used as a criterion for determining the distance of the terminal position from the base station. Further, it is determined whether or not the terminal position is a position that does not cause interference with the restricted area, based on a determination criterion that also takes into consideration the output of wireless transmission of the terminal.

If the comparison of the received signal strengths is not sufficient, the information obtained in the decoding process of the error correction code when extracting the control information for confirmation in the first wireless LAN wireless data extracting section 7-4 Based on the first wireless L
Bit error rate in an AN BER · C / N calculation section 7-6: calculating (B it E rror R ate BER ) and signal-to-noise ratio (C / N). Whether or not they exceed a predetermined threshold value or whether or not the result of calculation is varied is determined in a composite manner to determine whether or not the position of the communication terminal is in the communication permission area.

When it is determined in step 8-6 that the wireless communication device is within the communication permission area, the communication enable determination control unit 7-7 indicates that the communication control unit 6-8 can communicate. Is notified, and communication is started in step 8-7. If it is determined in step 8-6 that the wireless communication device is outside the communication permitted area, communication is not performed. During communication, the position of the communication terminal is periodically determined in step 8-8. The process of step 8-8 is required especially for the type in which the wireless communication device (terminal) moves. This is because the position of the wireless communication device (terminal) may fluctuate due to movement, and the wireless communication device (terminal) may move outside the communication-permitted area (outside the usage-restricted area). By the above processing, the communication within the restricted area can be surely restricted.

Next, a radio communication apparatus according to the second embodiment of the present invention will be described with reference to FIG. Reference will also be made to FIGS. 1 to 9 as appropriate. FIG. 10 is a flowchart for explaining the operation of the wireless communication device according to the second embodiment of the present invention, and is a diagram showing a process when performing communication using an empty channel. The flowchart shown in FIG. 10 is the same as the flowchart shown in FIG. 8 up to the communication permission area determination step 8-6. The carrier sense process of step 8-1 is called the first carrier sense process, and the second carrier sense process (step 9-
Distinguish from 1). When the first wireless LAN and the second wireless LAN use a wireless communication system that uses a predetermined frequency band as a plurality of frequency channels, an empty channel different from the frequency channel used by the first wireless LAN is used. It is conceivable to communicate with each other.

In this case, communication permission area determination step 8
When it is determined in -6 that the communication is within the communication permitted area, the second carrier sense processing 9-1 is performed. The second carrier sense processing 9-1 is the first carrier sense processing 8
-1, different from the first frequency channel 3-6 (FIG. 3) used by the first wireless LAN, a second, third or fourth frequency channel 3-7, 3-8, 3 Perform a carrier sense of -9. In step 9-2, it is determined whether the frequency channel is empty. If the frequency channel is vacant, communication is started using the vacant frequency channel in step 8-7.

Here, in order to periodically determine that the area is the communication-permitted area, it is necessary to check the frequency channel used by the first wireless LAN, not the frequency channel in which the communication is performed. Becomes For example, the ARIB STD-T70 described in the first embodiment.
In, the base station periodically transmits the control signal once every 2 ms. Also, ISO / IEC8802-11: 1
In 999, a control signal (beacon signal) is transmitted once every 1000 ms.

Therefore, the timer is operated in accordance with these cycles, and at the check timing of step 9-3, the recheck processing of step 9-4 is performed. Actually, in the recheck processing in step 9-4, the frequency channel for communication currently in communication is switched to the frequency channel used by the first wireless LAN, and step 8
In this process, the processes from -1 to step 8-6 are performed again.

Step 8 in this recheck processing 9-4
If it is confirmed in -6 that the wireless communication device of its own is located in the communication permitted area, the communication frequency channel is returned to the base and the communication is started in step 8-7. If it cannot be confirmed in step 8-6 that the wireless communication device of the user is located in the communication permitted area, the communication is ended. With the above processing, it is possible to perform the communication permission determination processing while using the idle frequency channel.

When determining whether or not the terminal is within the communication permission area, the result of comparing the received signal strengths and the BER
It may be possible to make a comprehensive determination in consideration of the result of comparing C / N and the result of comparing C / N. For example, it is possible to use a method of making a decision based on the majority decision of the three methods, a method of prioritizing the three methods, a method of performing a predetermined weighting process on the decision results, and the like.

Further, it is possible to provide a terminal position judging means having two or more different values as the preset threshold value or judgment criterion. For example, if the results of the two terminal position determination means match, the position determination result is updated, and
If the determination results of the one terminal position determination means do not match, the position determination may be set not to be updated.
Although the present invention has been described above with reference to the embodiments, the present invention is not limited thereto. It will be apparent to those skilled in the art that other various modifications, improvements, and combinations can be made.

[0085]

According to the present invention, it is possible to restrict the communication of the wireless communication device in the use restricted area where the existing wireless communication system exists.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of a wireless communication system according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing an environment on which a wireless communication device according to an embodiment of the present invention is used.

FIG. 3 (a) is a diagram showing a principle of dividing a radio wave in a predetermined frequency band into four frequency channels from a first to a fourth frequency channel, and FIG. 3 (b) is a diagram showing the principle; It is a chart figure which shows the utilization example of four frequency channels from 1st to 4th.

FIG. 4 is a diagram showing an example of using frequencies in a centralized control wireless communication system, FIG. 4 (a) is a diagram showing an example of a data structure for communication, and FIG. 4 (b) is a time chart of a frequency channel. It is an example of using the area.

[Fig. 5] Fig. 5 is a diagram illustrating an example of using frequencies in a distributed control wireless communication system, which is an example of using the time domain of a frequency channel.

FIG. 6 is a functional block diagram of the entire wireless communication device according to the first embodiment of the present invention.

FIG. 7 is a functional block diagram showing a structure of a wireless transmission / reception unit.

FIG. 8 is a flowchart showing the operation of the distributed control type wireless communication device in the wireless transmission system according to the first embodiment of the present invention.

FIG. 9 is a diagram for explaining a confirmation method by the confirmation means in the wireless communication device according to the present embodiment, and FIG.
9 is a diagram showing a data structure of a preamble, and FIG.
(B) is a diagram showing an example of frequency band allocation, which is a conceptual diagram for explaining the identification method based on the preamble.

FIG. 10 is a flowchart showing an operation of a distributed control type wireless communication device in the wireless transmission system according to the second embodiment of the present invention.

FIG. 11 is a diagram showing a configuration of a communication restriction method disclosed in the prior art.

[Explanation of symbols]

1-1 ... First relay base station, 1-2 ... Second relay base station, 1
-3 ... Third relay base station, 1-4 ... First base station, 1-5 ...
First terminal, 1-6 ... Second terminal, 1-7 ... First wireless LA
N, 1-8 ... Third terminal, 1-9 ... Fourth terminal, 1-10 ...
Second wireless LAN, 2-1 ... Restricted use area, 2-2 ...
Wireless LAN, 2-3 ... Wireless LAN, 2-4 ... Wireless LA
N, 2-5 ... Internet, 3-1 ... Frequency band, 3
-2 ... 1st frequency channel, 3-3 ... 2nd frequency channel, 3-4 ... 3rd frequency channel, 3-5 ... 4th frequency channel, AT ... Antenna, 6-1 ... Radio transmission / reception part, 6
-2 ... Demodulation circuit, 6-3 ... Modulation circuit, 6-4 ... Wireless data extraction unit, 6-5 ... Wireless data generation unit, 6-6 ... Received data storage unit, 6-7 ... Transmission data storage unit, 6 -8 ... communication control unit, 6-9 ... timing information generation circuit, 6-10 ...
Bus control circuit, PC ... Personal computer, 6-1
2 ... Antenna duplexer, 6-13 ... Wireless receiver, 6-14
... Wireless transmitter, 6-15 ... A / D converter, 6-16 ... D /
A conversion unit, 6-17 ... Preamble detection unit, 6-18 ...
Received power detection unit, 7-1 ... First wireless LAN preamble comparison unit, 7-2 ... First wireless LAN demodulation circuit, 7-3
... 1st wireless LAN received signal strength comparison part, 7-4 ... 1st
Wireless data extraction unit for wireless LAN, 7-5 ... First wireless LA
Control information confirmation unit for N, 7-6 ... BER for first wireless LAN
-C / N calculator, 7-7 ... Communication availability determination controller.

Continued front page    (72) Inventor Katsuyuki Machino             22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka             Inside the company F term (reference) 5K033 AA05 BA12 DA19 DB20 EA06                 5K051 AA02 BB01 BB02 CC07 DD11                       DD15 FF04 FF21 HH19                 5K067 AA03 BB02 BB21 DD11 DD19                       DD51 EE02 EE10 FF02 FF03                       JJ71                 5K101 KK02 LL05 LL12 MM02 NN14                       PP00 RR27

Claims (11)

[Claims] 1. A wireless communication device capable of communicating in a predetermined frequency band, the other wireless communication performing wireless communication only within a wireless communication permission area in which wireless communication using the predetermined frequency band is permitted. Confirmation means for receiving a system communication signal and confirming the presence of the other wireless communication system based on the received signal, and determining whether or not the position of the wireless communication device is within the wireless communication permission area A position determining means, and confirms the existence of the other wireless communication system,
A wireless communication device which is in a wireless communication enabled state only when it is determined that the wireless communication device is located within the wireless communication permission area. 2. The position determining means, the received signal strength measuring means for measuring the strength of the received signal, and the signal strength for comparing the strength of the received signal with a preset threshold value of signal strength. The wireless communication device according to claim 1, further comprising a determination unit. 3. The position determining means calculates a signal-to-noise ratio based on the received signal, a reception signal-to-noise ratio calculating means, and the signal-to-noise ratio and a preset signal-to-noise ratio. The wireless communication device according to claim 1, further comprising received signal-to-noise ratio determination means for comparing with a threshold value. 4. The position determining means compares the bit error rate calculating means for calculating an error rate based on the received signal with the bit error rate and a preset threshold value of the bit error rate. The wireless communication device according to claim 1, further comprising error rate determination means. 5. The confirmation means includes control information extraction means for extracting control information included in the received signal, and control information comparison means for comparing the extracted control information with preset control information. The wireless communication device according to any one of claims 1 to 4, further comprising: 6. The preamble signal extracting means for extracting a preamble signal included in the received signal, and the preamble comparing means for comparing the extracted preamble signal with a preset preamble signal pattern. The wireless communication device according to any one of claims 1 to 4, further comprising: 7. The checking means includes control information extracting means for extracting control information included in the received signal, and control information comparing means for comparing the extracted control information with preset control information. Any one of claims 1 to 4, further comprising: preamble signal extracting means for extracting a preamble signal included in the received signal; and preamble comparing means for comparing the extracted preamble signal with a preset preamble signal pattern. 2. The wireless communication device according to item 1. 8. The wireless communication device is capable of utilizing a plurality of frequency channels in the predetermined frequency band, detects a frequency channel being used by the other wireless communication system, and uses the frequency channel. The wireless communication system according to claim 1, wherein communication is performed by switching to a free frequency channel that is a frequency channel other than the medium frequency channel. 9. The wireless communication device is capable of utilizing a plurality of frequency channels in the predetermined frequency band, calculates timings for receiving signals necessary for the confirmation means and the position determination means, and calculates 8. The wireless communication device according to claim 1, further comprising channel switching timing control means for switching from a frequency channel currently in use to a frequency channel capable of receiving the required signal in accordance with the timing. 10. A first wireless communication system that performs wireless communication only within a wireless communication permitted area in which wireless communication using a predetermined frequency band is permitted, and a wireless communication device that performs communication in the predetermined frequency band. A second wireless communication system including: a confirmation unit that receives a communication signal of the first wireless communication system and confirms the presence of the first wireless communication system based on the received signal; A wireless communication system including a second wireless communication system including a wireless communication device including position determining means for determining whether or not the position of the communication device is within the wireless communication permission area. 11. A second wireless communication system for performing communication in the same frequency band as a predetermined frequency band used by a first wireless communication system for performing wireless communication only within a wireless communication permitted area where wireless communication is permitted. A wireless communication method, comprising: (a) receiving a communication signal of the first wireless communication system and confirming the presence of the first wireless communication system based on the received signal; and (b) the wireless communication method. Determining whether the position of the communication device is within the wireless communication permission area; (c) confirming the existence of the first wireless communication system in step (a); and performing the step (b). The method of performing wireless communication only when it is determined that the wireless communication is within the wireless communication permission area.