JP2006174328A - Communication system and wireless terminal synchronization method - Google Patents

Abstract

Synchronizing an internal clock of a wireless terminal constituting a communication system.
In a communication system including a wireless terminal, a base station that communicates with the wireless terminal, and a communication server that controls communication between the wireless terminal and the base station, the base station counts time. A first counting unit, and a first transmission unit that transmits a wireless packet including the contents of the first counting unit to the wireless terminal, wherein the wireless terminal counts a second time. A terminal synchronization unit that writes the content of the first counting unit included in the wireless packet received from the base station to the second counting unit, a measuring unit that measures the state of the object, and the measuring unit A second transmitter that transmits to the base station a wireless packet that includes the state of the object measured by the measurement unit and the content of the second counter when the state of the object is measured by the measuring unit. It is characterized by.
[Selection] Figure 1

Description

  The present invention relates to a communication system including a base station and a plurality of wireless terminals, and more particularly to a technique for synchronizing timers in wireless terminals using wireless packets.

  A communication system using radio includes a radio terminal, a base station, and a communication server. The communication server is connected to a plurality of base stations by wires, and controls the connected base stations. Each base station communicates with a wireless terminal.

  In such a communication system, it is possible to communicate with a large number of wireless terminals by using a frequency division multiplexing method or a time division multiplexing method. In frequency division multiplexing, communication is performed while switching the communication frequency between the base station and the wireless terminal. In the time division multiplexing method, a time frame called a wireless packet divided finely is assigned to communication between a base station and a wireless terminal. In these methods, it is necessary to synchronize the clock timing between the base station and the wireless terminal and between different base stations in order to prevent frequency interference and simultaneous transmission of wireless packets.

  The base station is connected to the communication server by wire. Therefore, the clock timing between the base stations can be synchronized by distributing the reference clock to each base station.

  In addition, a technique for synchronizing a base station and a wireless terminal using a wireless packet is known (see Patent Document 1). Specifically, the base station transmits a wireless packet including a synchronization clock to the wireless terminal. Then, the wireless terminal corrects its own clock timing using the synchronization clock in the received wireless packet. Thereby, the clock timing between the base station and the wireless terminal can be synchronized.

  In recent years, a wireless communication system in which a sensor is mounted on a wireless terminal and various sensor data are acquired and analyzed using a large number of wireless terminals has attracted attention. In this communication system, it is necessary for the communication server to obtain an accurate acquisition time of sensor data. For example, when the sensor data is electrocardiogram data, heart rate, blood pressure value, etc., if the acquisition time of the sensor data is not accurate, a diagnosis error occurs.

For this purpose, it is necessary to synchronize the internal clocks of the wireless terminals constituting the communication system.
Japanese Patent Laid-Open No. 2003-274349

  However, in the prior art, the clock timing of the wireless terminals constituting the communication system can be synchronized, but the internal clock of the wireless terminals constituting the communication system cannot be synchronized.

  Therefore, an object of the present invention is to synchronize the internal clocks of the wireless terminals constituting the communication system, and to obtain the acquisition time of sensor data together with the sensor data.

  In a communication system including a wireless terminal, a base station that communicates with the wireless terminal, and a communication server that controls communication between the wireless terminal and the base station, the base station counts a first time. And a first transmission unit that transmits a wireless packet including the content of the first counting unit to the wireless terminal, the wireless terminal includes a second counting unit that counts time, Measured by the terminal synchronization unit that writes the content of the first counting unit included in the wireless packet received from the base station into the second counting unit, the measuring unit that measures the state of the object, and the measuring unit A second transmitter that transmits to the base station a wireless packet that includes the state of the object and the content of the second counting unit when the state of the object is measured by the measuring unit; .

  ADVANTAGE OF THE INVENTION According to this invention, the internal clock of the radio | wireless terminal which comprises a communication system can be synchronized, and also the acquisition time of sensor data can be obtained with sensor data.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram of a configuration of a communication system according to an embodiment of the present invention.

  The communication system includes a base station 1, a communication server 2, a wireless terminal 3, and a sensor 7. In this communication system, the measuring body 8 can be measured by the sensor 7 and the measured sensor data can be acquired by the communication server 2. The measuring body 8 is a living body including a human body, for example.

  Although three base stations 1 and three wireless terminals 3 are illustrated, any number of base stations 1 and wireless terminals 3 may be provided. In addition, although the base station 1 and the wireless terminal 3 communicate on a one-to-one basis, one base station 1 may communicate with a plurality of wireless terminals 3. For example, the base station 1A may communicate with three of the wireless terminal 3A, the wireless terminal 3B, and the wireless terminal 3C. However, the wireless terminal 3 communicates with only one base station 1 at the same time. For example, the wireless terminal 3A in communication with the base station 1A cannot communicate with other base stations 1B and the like.

  The communication server 2 communicates with the wireless terminal 3 via the base station 1. The communication server 2 includes a timer 204 and transmits a timer signal including the value of the timer 204 to the base station 1. The timer 204 is an internal clock of the communication server 2.

  The base station 1 includes a base station synchronization timer 104. The base station synchronization timer 104 is an internal clock of the base station 1. The base station 1 synchronizes the base station synchronization timer 104 with the timer 204 of the communication server 2 using the timer signal received from the communication server 2.

  The wireless terminal 3 includes a terminal synchronization timer 304. The terminal synchronization timer 304 is an internal clock of the wireless terminal 3. The wireless terminal 3 synchronizes the terminal synchronization timer 304 with the base station synchronization timer 104 of the base station 1 by the process of FIG.

  That is, the timer 204, the base station synchronization timer 104, and the terminal synchronization timer 304 are all synchronized.

  The sensor 7 is connected to the wireless terminal 3. The sensor 7 measures the temperature, blood pressure, and the like of the measurement body 8 and transmits the measured sensor data to the wireless terminal 3. When the wireless terminal 3 receives the sensor data from the sensor 7, the wireless terminal 3 creates a packet by adding the value of the terminal synchronization timer 304 when the sensor 7 measures the measuring body 8 to the sensor data, and sends the created packet to the base station 1. (Details will be described later in FIG. 9). When receiving a packet from the wireless terminal 3, the base station 1 transfers the received packet to the communication server 2 (details will be described later with reference to FIG. 10).

  As described above, the communication server 2 can acquire sensor data together with the value of the terminal synchronization timer 304 when the sensor 7 measures the measuring body 8. Since the terminal synchronization timer 304 and the timer 204 are synchronized, the communication server 2 can know the time when the sensor 7 acquired the sensor data.

  FIG. 2 is a block diagram of a configuration of the base station 1 according to the embodiment of this invention.

  The base station 1 includes a baseband control unit 101, a terminal data storage unit 102, a timer synchronization unit 103, a base station synchronization timer 104, an RF control unit 105, and a CPU 106.

  The baseband control unit 101 controls a communication protocol in wireless communication with the wireless terminal 3. The terminal data storage unit 102 stores sensor data received from the wireless terminal 3. The timer synchronization unit 103 synchronizes the base station synchronization timer 104 with the timer 204 of the communication server 2 using the timer signal received from the communication server 2. The base station synchronization timer 104 is an internal clock of the base station 1. The RF control unit 105 controls the physical layer in wireless communication with the wireless terminal 3. The CPU 106 controls the entire base station 1.

  FIG. 3 is a block diagram of a configuration of the communication server 2 according to the embodiment of this invention.

  The communication server 2 includes a data control unit 200, a communication control unit 201, a display memory 202, a display unit 203, and a timer 204.

  The data control unit 200 stores the sensor data received from the base station 1 in the display memory 202. The communication control unit 201 controls communication with the base station 1. In addition, the communication control unit 201 transmits a timer signal including the value of the timer 204 to the communication server 2. The display memory 202 stores sensor data received from the base station. The display unit 203 displays the contents stored in the display memory 202. The timer 204 is an internal clock of the communication server 2.

  FIG. 4 is a block diagram of a configuration of the wireless terminal 3 according to the embodiment of this invention.

  The wireless terminal 3 includes an RF circuit 301, a terminal memory 302, a timer synchronization circuit 303, a terminal synchronization timer 304, a terminal identification register 305, a terminal control circuit 306, and a sensor control circuit 307. The wireless terminal 3 is connected to the sensor 7.

  The RF circuit 301 controls a physical layer in wireless communication with the base station 1. The terminal memory 302 stores sensor data received from the sensor 7. The timer synchronization circuit 303 synchronizes the terminal synchronization timer 304 with the base station synchronization timer 104 of the base station 1. The terminal synchronization timer 304 is an internal clock of the wireless terminal 3. The terminal identification register 305 stores an identifier that uniquely identifies the wireless terminal 3. The terminal control circuit 306 controls a communication protocol in wireless communication with the base station 1. The sensor control circuit 307 acquires sensor data from the connected sensor 7 and stores the acquired sensor data in the terminal memory 302.

  FIG. 5 is a block diagram of a configuration of the base station packet 501 transmitted from the base station 1 to the wireless terminal 3 according to the embodiment of this invention.

  The base station packet 501 is composed of control data 502 and base station data 503. The control data 502 is information for controlling a communication protocol in wireless communication between the base station 1 and the wireless terminal 3. The base station data 503 is information transmitted from the base station 1 to the wireless terminal 3 and includes a base station synchronization timer value 504. The base station synchronization timer value 504 stores the value of the base station synchronization timer 104 when the base station packet 501 is transmitted.

  FIG. 6 is a block diagram of a configuration of a terminal packet 801 transmitted from the wireless terminal 3 to the base station 1 according to the embodiment of this invention.

  The terminal packet 801 includes terminal control data 802 and terminal data 803. The terminal control data 802 is information for controlling a communication protocol in wireless communication between the base station 1 and the wireless terminal 3. The terminal data 803 is information transmitted from the wireless terminal 3 to the base station 1 and includes a terminal identification number 804, sensor data acquisition time 805, and sensor data 806. The terminal data 803 may include a plurality of sensor data acquisition times 805 and sensor data 806.

  The terminal identification number 804 stores the identifier of the wireless terminal 3 that transmits the packet. The sensor data acquisition time 805 stores the value of the terminal synchronization timer 304 when the sensor 7 measures the measuring body 8. The sensor data 806 stores the content of the measurement object 8 measured by the sensor 7.

  FIG. 7 is a flowchart of the synchronization processing of the base station 1 according to the embodiment of this invention.

  First, a timer signal is received from the communication server 2. The edge of its own clock timing is made the same as the edge of the received timer signal. Accordingly, the own clock timing is corrected to be the same as the clock timing of the communication server 2 (S601).

  Next, the value of the timer 204 included in the timer signal is set in the base station synchronization timer 104 at the corrected clock timing (S602).

  Next, an inquiry packet is transmitted within the communicable area (S603). Then, it is determined whether a response packet is received from the wireless terminal 3 (S604).

  If the response packet is not received, the wireless terminal 3 to be synchronized does not exist within the communicable area, and the synchronization process is terminated (S608).

  On the other hand, when a response packet is received from the wireless terminal 3, since the wireless terminal 3 to be synchronized exists within the communicable area, information on transmission timing is extracted from the received response packet. The transmission timing is a timing at which the wireless terminal 3 can communicate with the base station 1 and is included in the response packet. Next, it is determined whether or not the extracted transmission timing has been reached (S605).

  If it is not the transmission timing, it waits until the transmission timing is reached. On the other hand, at the transmission timing, the value of the base station synchronization timer 104 is stored in the base station packet 501 (S606). Then, the base station packet 501 storing the value 504 of the base station synchronization timer is transmitted to the wireless terminal 3 (S607), and the process returns to step S603.

  By repeating step S603 and subsequent steps, all the wireless terminals 3 existing in the communicable area can be synchronized.

  FIG. 8 is a flowchart of the synchronization processing of the wireless terminal 3 according to the embodiment of this invention.

  First, it is determined whether an inquiry packet is received from the base station 1 (S701). If an inquiry packet has not been received, it waits until it is received.

  On the other hand, when the inquiry packet is received, the timing (transmission timing) at which communication with the base station can be performed is determined. Next, a response packet including the transmission timing is transmitted to the base station 1 (S702).

  Next, it is determined whether or not the base station packet 501 has been received from the base station 1 (S703). If the base station packet 501 has not been received, it waits until it is received.

  On the other hand, when the base station packet 501 is received, the edge of its own clock timing is made the same as the edge of the received base station packet 501. As a result, the own clock timing is corrected to be the same as the clock timing of the base station 1 (S704).

  Next, the base station synchronization timer value 504 is extracted from the received base station packet 501 (705). Then, the extracted base station synchronization timer value 504 is set in the terminal synchronization timer 304 at the corrected clock timing (S706), and the synchronization processing is terminated (S707).

  As described above, the terminal synchronization timer 304 of the wireless terminal 3 and the base station synchronization timer 104 of the base station 1 are synchronized using the base station packet 501. Further, the timer 204 of the communication server 2 and the base station synchronization timer 104 of the base station 1 are synchronized using the timer signal. Therefore, the communication system of the present embodiment can synchronize the internal clocks in all devices.

  FIG. 9 is a flowchart of sensor data transmission processing of the wireless terminal 3 according to the embodiment of this invention.

  First, sensor data is acquired from the sensor 7 (S901). Next, the value of the terminal synchronization timer 304 when sensor data is acquired is extracted (S902), and the extracted value is set as the sensor data acquisition time. Next, the acquired sensor data and sensor data acquisition time are stored in the terminal memory 302 (S903).

  Next, it is determined whether it is time to transmit the packet to the base station 1 (S904). The transmission timing may be a predetermined interval determined in advance, or may be instructed from the base station 1.

  If it is not time to transmit the packet, the process returns to step S901. Thus, the acquisition of sensor data is repeated until the timing for transmitting the packet to the base station 1 is reached.

  On the other hand, when it is time to transmit the packet, the terminal packet 801 is assembled (S905). Specifically, the terminal identification number is stored in the terminal data 803, and the sensor data acquisition time and sensor data stored in the terminal memory 302 are stored in the terminal data 803, thereby assembling the terminal packet 801.

  Then, the assembled terminal packet 801 is wirelessly transmitted to the base station 1 (S906), and the sensor data transmission process is terminated (S907).

  FIG. 10 is a flowchart of the sensor data transfer process of the base station 1 according to the embodiment of this invention.

  First, it is determined whether or not the terminal packet 801 has been received from the wireless terminal 3 (S1001). If the terminal packet 801 has not been received, it waits until it is received.

  On the other hand, when the terminal packet 801 is received, terminal data 803 is extracted from the received terminal packet 801. Next, the extracted terminal data 803 is stored in the terminal data storage unit 102 (S1002).

  Next, it is determined whether or not the terminal data 803 is requested from the communication server 2 (S1003).

  If the terminal data 803 is not requested, the process returns to step S1001. Accordingly, the terminal packet 801 reception process is repeated until the terminal data 803 is requested from the communication server 2.

  When the terminal data 803 is requested from the communication server 2, the terminal data 803 stored in the terminal data storage unit 102 is transmitted to the communication server 2 (S1004), and the transfer process is terminated (S1005).

  FIG. 11 is a flowchart of terminal data 803 storage processing of the communication server 2 according to the embodiment of this invention.

  First, terminal data 803 is requested from the base station 1 (S1101). Then, it is determined whether or not the terminal data 803 is received from the base station 1 (S1102). If the terminal data 803 has not been received, it waits until it is received.

  On the other hand, when the terminal data 803 is received, the terminal identification number 804 is extracted from the received terminal data 803. The received terminal data 803 is stored in the display memory 202 for each extracted terminal identification number 804 (S1103).

  Next, terminal data 803 is requested from the base station 1 (S1104). Then, it is determined whether or not the terminal data 803 has been received from the base station 1 (S1105). If the terminal data 803 has not been received, it waits until it is received.

  On the other hand, when the terminal data 803 is received, the terminal identification number 804 is extracted from the received terminal data 803. The received terminal data 803 is stored in the display memory 202 for each extracted terminal identification number 804 (S1106).

  Next, the sensor data acquisition time 805 is extracted from the terminal data 803 stored in the display memory 202 in the previous and current step S1106. If there is no terminal data 803 stored in the display memory in the previous step S1106, the terminal data 803 stored in the display memory 202 in step S1103 is used instead.

  Next, the extracted sensor data acquisition time 805 is compared (S1107). Then, it is determined whether or not the terminal data 803 stored in the current step S1106 has an earlier sensor data acquisition time 805 than the terminal data 803 stored in the previous step S1106 (S1108).

  If the sensor data acquisition time 805 of the terminal data 803 stored in the current step S1106 is late, the terminal data 803 is stored in the order of the sensor data acquisition time 805, and thus the process proceeds to step S1110.

  On the other hand, when the sensor data acquisition time 805 of the terminal data 803 stored in the current step S1106 is earlier, the terminal data 803 stored in the current step S1106 and the terminal data 803 stored in the previous step S1106 are switched (S1109). Thereby, the terminal data 803 can be stored in the display memory 202 in the order of the sensor data acquisition time 805 as shown in FIG.

  Next, terminal data 803 is requested from the base station 1 (S1110). Then, it is determined whether or not the terminal data 803 is received from the base station 1 within a predetermined time (S1111).

  If the terminal data 803 is received within a predetermined time, the process returns to step S1106 to process the newly received data.

  On the other hand, if the terminal data 803 is not received within a predetermined time, it is determined that all the terminal data 803 stored in the terminal data storage unit 102 of the base station 1 has been received, and the terminal data 803 storage process is terminated.

  FIG. 12 is an explanatory diagram of the display memory 202 in which the terminal data 803 according to the embodiment of this invention is stored.

  The display memory 202 stores terminal data 803 for each wireless terminal 3. Further, terminal data 803 is stored in the display memory 202 in the order of the data acquisition time 805. The terminal data 803 includes a data acquisition time 805 and sensor data 806.

  FIG. 13 is an explanatory diagram of the display unit 203 that displays the contents of the display memory 202 according to the embodiment of this invention.

  The display unit 203 displays sensor data 806 for each wireless terminal 3. The display unit 203 displays a time axis, and displays sensor data 806 in association with the sensor data acquisition time 805 and the time axis. By the display unit 203 displaying in this way, the user can easily grasp the state of the measuring body 8 for each time.

  As described above, in the present embodiment, the time of the entire communication system is synchronized. Further, the wireless terminal 3 acquires sensor data using the sensor 7 and extracts the value of the terminal synchronization timer 304 when the sensor data is acquired. Then, the wireless terminal 3 transmits the sensor data and the value of the terminal synchronization timer 304 to the communication server 2 via the base station 1. Thereby, the information server 2 can acquire the time when the sensor data is measured together with the sensor data. Furthermore, the time axes of sensor data measured by different sensors 7 can be matched.

  The present invention can be applied to a wireless communication system including a plurality of base stations. In particular, in the medical field, it is effective when applied to a wireless communication system of a medical device that acquires patient biometric data using a plurality of wireless terminals and wirelessly transfers the data to a base station.

It is a block diagram of the structure of the communication system of embodiment of this invention. It is a block diagram of the structure of the base station of embodiment of this invention. It is a block diagram of the structure of the communication server of embodiment of this invention. It is a block diagram of a structure of the radio | wireless terminal of embodiment of this invention. It is a block diagram of the structure of the base station packet transmitted to the radio | wireless terminal from the base station of embodiment of this invention. It is a block diagram of the structure of the terminal packet transmitted to the base station from the radio | wireless terminal of embodiment of this invention. It is a flowchart of the synchronous process of the base station of embodiment of this invention. It is a flowchart of the synchronous process of the radio | wireless terminal of embodiment of this invention. It is a flowchart of the sensor data transmission process of the radio | wireless terminal of embodiment of this invention. It is a flowchart of the sensor data transfer process of the base station of embodiment of this invention. It is a flowchart of the terminal data storage process of the communication server of embodiment of this invention. It is explanatory drawing of the display memory in which the terminal data of embodiment of this invention were stored. It is explanatory drawing of the display part which displayed the content of the display memory of embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base station 2 Communication server 3 Wireless terminal 7 Sensor 8 Measuring object 101 Baseband control part 102 Terminal data storage part 103 Timer synchronization part 104 Base station synchronization timer 105 RF control part 106 CPU
200 Data control unit 201 Communication control unit 202 Display memory 203 Display unit 204 Timer 301 RF circuit 302 Terminal memory 303 Timer synchronization circuit 304 Terminal synchronization timer 305 Terminal identification register 306 Terminal control circuit 307 Sensor control circuit

Claims (4)

In a communication system including a wireless terminal, a base station that communicates with the wireless terminal, and a communication server that controls communication between the wireless terminal and the base station,
The base station
A first counting unit for counting time;
A first transmission unit that transmits a wireless packet including the content of the first counting unit to the wireless terminal;
The wireless terminal is
A second counting unit for counting time;
A terminal synchronization unit that writes the contents of the first counting unit included in the wireless packet received from the base station to the second counting unit;
A measurement unit for measuring the state of the object;
A second transmission unit that transmits to the base station a wireless packet including the state of the object measured by the measurement unit and the contents of the second counting unit when the state of the object is measured by the measurement unit; A communication system characterized by comprising: The communication server is
A third counting unit for counting time;
A third transmitter for transmitting the contents of the third counter to the base station,
The base station
The communication system according to claim 1, further comprising a base station synchronization unit that writes the content of the third counting unit received from the communication server to the first counting unit. A wireless terminal having a measuring unit that measures the state of an object and a first counting unit that counts time, a base station that has a second counting unit that communicates with the wireless terminal and counts time, and the wireless terminal And a communication server having a third counting unit that controls communication with the base station and counts time, and a wireless terminal synchronization method in a communication system,
The base station
Transmitting a wireless packet including the contents of the first counting unit to the wireless terminal;
The wireless terminal is
Write the contents of the first counter included in the wireless packet received from the base station to the second counter,
A radio that includes a state of an object measured by the measuring unit and a content of the second counting unit when the state of the object is measured by the measuring unit is transmitted to the base station. Device synchronization method. The communication server transmits the content of the third counting unit to the base station,
The wireless terminal synchronization method according to claim 3, wherein the base station writes the content of the third counting unit received from the communication server into the first counting unit.

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