JP4623197B2 - Wireless terminal device, wireless relay device, and program - Google Patents

Description

  The present invention relates to a wireless terminal device, a wireless relay device, and a program.

  In recent years, development of a wireless communication system that constructs a wireless network between a plurality of electronic devices and performs information communication has been advanced. In particular, the development of the field of small-scale wireless PAN (Personal Area Network) in which a person's surroundings are within the communication range is being promoted and is rapidly spreading. This wireless PAN is, for example, ZigBee (registered trademark) in which the physical layer and the MAC layer are standardized in IEEE 802.15, and Bluetooth (registered trademark) in which the physical layer and the MAC layer are standardized in IEEE 802.15.1. It is realized by using.

  ZigBee is standardized by the ZigBee Alliance and uses IEEE802.15.4 for the physical layer and the MAC layer. Therefore, ZigBee is characterized by low cost, low power consumption, and easy installation, while being slower than Bluetooth, and the wireless relay device can be connected to many wireless terminal devices.

  A wireless communication system using ZigBee includes a wireless relay device and a wireless terminal device. A beacon mode is often used as a communication method of this wireless communication system. In the beacon mode, the wireless relay device periodically transmits a beacon signal at a predetermined cycle, all wireless terminal devices receive the beacon, and the wireless terminal device is the wireless relay device in synchronization with the received beacon. Wireless communication.

  When transmitting data from the wireless relay device to the wireless terminal device, the wireless relay device stores and transmits the address of the wireless terminal device that transmits data in the pending address in the beacon. The wireless terminal device that has received the beacon transmits a data request to the wireless relay device and receives data when the beacon has its own address.

  In the wireless communication system as described above, the maximum number of wireless terminal device addresses that can be stored in the pending address is up to 7 and is defined by IEEE 802.15.4. Therefore, for example, in a wireless communication system composed of one wireless relay device and a large number of eight or more wireless terminal devices, even when data is transmitted to all wireless terminal devices, Only up to 7 addresses can be stored. Therefore, although only a maximum of seven wireless terminal devices can receive data in one beacon transmission, all wireless terminal devices perform a receiving operation for each beacon transmission time. For this reason, since the wireless terminal device receives a beacon even when it is not necessary to receive data, there is a problem that power is wasted.

Therefore, in a wireless communication system, as a technique for reducing power consumption of a wireless terminal device, when an access point (wireless relay device) transmits data to the wireless terminal device, data indicating the next data transmission time is sent together with the data. It is disclosed that a wireless terminal device is prevented from receiving data other than that addressed to the own station (see Patent Document 1).
JP 2002-300195 A

  However, when the invention described in Patent Document 1 is applied to a wireless communication system having a beacon mode, the wireless terminal device must continue to maintain a beacon receivable state until a beacon addressed to itself can be received. Therefore, in the case of a wireless communication system in which a large number of wireless terminal devices exist, such as an electronic shelf label, there is a problem that a large number of wireless terminal devices that have to maintain a wasteful reception operation for a long time occur.

  In view of the above problems, an object of the present invention is to save power in a wireless terminal device.

In order to solve the above problems, the invention according to claim 1 is a wireless terminal device including a receiving unit that receives a beacon, wherein the beacon indicates a group to which a wireless terminal device that is a reception target of the beacon belongs. Based on the identification information storage unit that includes the identification information and stores the terminal identification information for identifying itself, the group identification information included in the beacon received by the reception unit, and the terminal identification information A wireless terminal apparatus comprising: a control unit that calculates a timing for starting the unit and stops the operation of the reception unit until the calculated timing.
Furthermore, a program is provided for causing a computer to function as each unit shown in the first aspect of the present invention (the seventh aspect of the present invention).

  According to a second aspect of the present invention, in the wireless terminal device according to the first aspect, the group identification information includes a sequence number that increases every time a beacon is transmitted and a total number of groups that divide the plurality of wireless terminal devices. Mask information in which a value to be extracted from the sequence number is determined based on the first identification value indicating a value extracted from the sequence number using the mask information, and the terminal identification A third calculated value indicating a value obtained by calculating a difference value with a second calculated value indicating a value extracted from the information using the mask information and multiplying the preset beacon transmission interval by the difference value And the operation of the receiving unit is stopped until the timing based on the time when the third calculated value is added to the time when the beacon is received.

  According to a third aspect of the present invention, in the wireless terminal device according to the first or second aspect, the control unit includes the beacon received by the receiving unit based on the group identification information and the terminal identification information. It is characterized by discriminating that it is a beacon addressed to a group.

  According to a fourth aspect of the present invention, in the wireless terminal device according to the third aspect, the beacon includes terminal identification information of the wireless terminal device that is a transmission target of data, and the control unit is received by the receiving unit. When the received beacon is a beacon addressed to the group to which it belongs, if the beacon includes its own terminal identification information, the receiving unit receives data.

Invention of claim 5, wherein a transmitting section and the radio terminal shown a group of devices belonging to group identification information as a reception target of the beacon periodically transmits a beacon to the wireless terminal, to the group A control unit that generates the beacon including group identification information for calculating a timing to activate a reception unit of the wireless terminal device to which the wireless terminal device belongs, and transmits the generated beacon to the wireless terminal device by the transmission unit. A wireless relay device characterized by the above.
Furthermore, a program is provided for causing a computer to function as each component shown in the invention described in claim 5 (the invention described in claim 8).

  A sixth aspect of the present invention is the wireless relay device according to the fifth aspect, further comprising a terminal information storage unit that stores information for each wireless terminal device capable of communication, and the group identification information is a beacon transmission time. A sequence number that increases every time, and mask information in which a value to be extracted from the sequence number is determined based on a total number of groups that divide a plurality of the wireless terminal devices, and the control unit includes the terminal information The mask information is determined according to the number of the wireless terminal devices stored in the storage unit.

  According to the present invention, it is possible to save power in the wireless terminal device.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to this embodiment. The embodiment of the present invention shows the most preferable mode of the present invention, and the terminology of the present invention is not limited to this.

First, the configuration will be described.
FIG. 1 shows a schematic configuration diagram of a wireless communication system A in the present embodiment.

  As shown in FIG. 1, a wireless communication system A includes a wireless relay device 1 connected to another wireless relay device or an external device via a wired network 3, and a plurality of wireless relay devices 1 connected to the wireless relay device 1 via wireless communication. Wireless terminal device 2.

FIG. 2 shows a schematic configuration diagram of the wireless relay device 1.
As shown in FIG. 2, the wireless relay device 1 includes a control unit 10, a storage unit 11, a terminal information memory 12, a beacon transmission timer 13, a wireless transmission unit 14, a wireless reception unit 15, a SW (switching unit) 16, a wired connection An I / F (InterFace) unit 17, a buffer 18, an antenna 19 and the like are provided, and each unit is electrically connected.

  The control unit 10 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The control unit 10 reads programs, tables, and data specified from various programs, various tables, data, and the like stored in the storage unit 11 and the terminal information memory 12, and is used for RAM or the storage unit 11 and terminal information. The data is expanded in the work area of the memory 12, and various processes are executed in cooperation with the program. The processing results are stored in the RAM or a predetermined area of the storage unit 11 or the terminal information memory 12, and the wireless relay device 1 is instructed to control the overall operation of the wireless relay device 1.

  The control unit 10 generates a beacon including group identification information, and executes a beacon transmission process in which the generated beacon is periodically transmitted to the wireless terminal device 2 by the wireless transmission unit 14. A beacon is packet data transmitted from the wireless relay device 1 at regular intervals, and is for synchronizing the wireless terminal device 2 and the wireless relay device 1 connected to the wireless communication system A.

FIG. 3 shows an example of a beacon format in the present embodiment.
As shown in FIG. 3, the beacon has a MAC (Media Access Control) header area B1, a MAC payload area B2, and an MFR (MAC Footer) area B3.

  The MAC payload area B2 includes an SS (Superframe Specification) B21, a GTS (Guaranteed Time Slot) field B22, a PA (Pending Address) field B23, a beacon payload B24, and the like.

  SS is a detailed information field of a superframe, and defines a beacon transmission interval and a beacon communication method for time management when a beacon is received. The GTS field includes information on a communication method (for example, GTS) guaranteed by a specific wireless terminal device. When there is data to be transmitted to the wireless terminal device, the PA field includes identification information (node address) for identifying the wireless terminal device that transmits the data. The beacon payload B24 includes an extended sequence number B24a and a mask bit B24b.

  The extended sequence number increases every time a beacon is transmitted, and functions as a sequence number. The mask bit defines a value to be extracted from the extended sequence number based on the total number of groups that divide a plurality of wireless terminal devices, and functions as mask information. The extended sequence number and the mask bit function as group identification information indicating a group to which a wireless terminal device that is a beacon reception target belongs.

  The storage unit 11 includes a nonvolatile memory that can be electrically erased and rewritten, such as a magnetic or optical recording medium or a semiconductor. The storage unit 11 is fixedly attached to the wireless relay device 1 or is detachable. It is to be attached. For example, FeRAM (Ferroelectric Random Access Memory), MRAM (Magneto resistive Random Access Memory), OUM (phase change recording memory by chalcogenide alloy), etc. can be mentioned. The storage unit 11 stores in advance various programs executed by the control unit 10 and various tables and data used by these programs.

  The terminal information memory 12 is composed of a memory that can be electrically erased and rewritten. The terminal information memory 12 stores information such as the node address of the wireless terminal device 2 existing in the communicable area of the wireless relay device 1 itself, and functions as a terminal information storage unit.

  The beacon transmission timer 13 is a timer that times the beacon transmission interval, and outputs a beacon transmission timing signal indicating that the time has reached the transmission interval to the control unit 10.

  The wireless transmission unit 14 includes a modulation circuit, an RF (Radio Frequency) circuit, and the like, adjusts the transmission power of the packet, encodes the data to be transmitted in accordance with an instruction from the control unit 10, and transmits the packet. The packet is modulated, and the packet is transmitted to the wireless terminal device 2 via the antenna 19.

  The wireless receiving unit 15 includes a demodulation circuit, an RF circuit, and the like, and is obtained by adjusting the reception sensitivity of the packet, demodulating the packet received via the antenna 19, and analyzing the demodulated packet. The data is output to the control unit 10.

  The SW 16 is provided between the antenna 19 and the wireless transmission unit 14 or the wireless reception unit 15, and transmits a packet from the wireless transmission unit 14 or receives a packet from the antenna 19 in accordance with an instruction from the control unit 10. Switch.

  The wired I / F 17 performs communication control for communicating with another wireless relay device 1 or an external device connected via the wired network 3 by a predetermined communication method.

  The buffer 18 temporarily stores data received via the wired I / F 17.

  The antenna 19 transmits a packet according to the set transmission power or receives a packet according to the set reception sensitivity.

FIG. 4 shows a schematic configuration diagram of the wireless terminal device 2.
As shown in FIG. 4, the wireless terminal device 2 includes a control unit 20, a storage unit 21, an address memory 22, an activation timer 23, a power supply control unit 24, a display control unit 25 a, a display unit 25 b, a wireless transmission unit 26, A wireless receiving unit 27, a SW (switching unit) 28, an antenna 29, and the like are provided, and each unit is electrically connected. The wireless terminal device 2 includes a battery B, and power is supplied from the battery B to each unit in response to a control signal from the power supply control unit 24.

  The control unit 20 includes a CPU, a ROM, a RAM, and the like, reads out various programs stored in the storage unit 21, various programs and tables and data specified from various tables and data, and stores them in the RAM or the storage unit 21. In the work area, execute various processes in cooperation with the above program, store the processing results in a predetermined area of the RAM or storage unit 21, and instruct each unit in the wireless terminal device 2, The overall operation of the wireless terminal device 2 is comprehensively controlled.

  Based on the group identification information (extended sequence number and mask bit) included in the beacon received by the radio reception unit 27 and the node address held in the address memory 22, the control unit 20 A timing for starting the receiving unit (starting timing) is calculated, and a beacon receiving process for stopping the operation of the wireless receiving unit 27 is executed until the calculated starting timing.

  As the calculation of the activation timing, the control unit 20 includes a first calculated value indicating a value extracted from the extended sequence number using a mass bit, and a second calculated value indicating a value extracted from its own node address using a mask bit; A third calculated value indicating a value obtained by multiplying a preset beacon transmission interval (beacon interval) by the difference value is calculated, and a third calculation is performed at the time (T) when the beacon is received. The time when the values are added is calculated as the activation timing.

  Furthermore, the control unit 20 determines that the beacon received by the wireless reception unit 27 is a beacon addressed to the group to which the control unit 20 belongs based on the extension sequence number, the mask bit, and the node address. If the beacon received by the wireless receiver 27 is a beacon addressed to the group to which the wireless receiver 27 belongs, the controller 20 sends a data request by the wireless transmitter 26 if the PA field of the beacon includes its own node address. And the wireless receiving unit 27 executes a process of receiving data from the wireless relay device 1.

FIG. 5 shows an example of the extended sequence number, mask bit, and node address. A calculation example of the first calculated value and the second calculated value will be described with reference to FIG.
As shown in FIG. 5, the extended sequence number, the mask bit, and the node address are each 2 bytes (16 bits) in binary. In FIG. 5, an explanation will be given using an example in which the extended sequence number is represented as “AAAA”, the mask bit is “0003”, and the node address is “FFAA” in hexadecimal. FIG. 5 shows hexadecimal values corresponding to binary values shown every 4 bits.

  The first calculated value is a value obtained by ANDing the extended sequence number and the mask bit. In FIG. 5, the shaded bit value “10” of the extended sequence number corresponding to the bit having 1 of the mask bit is calculated as the first calculated value. The second calculated value is a value obtained by ANDing the node address and the mask bit. In FIG. 5, the shaded bit value “10” of the node address corresponding to the bit having 1 of the mask bit is calculated as the second calculation.

  When the lower 2 bits of the mask bit are 1, the first calculated value and the second calculated value extracted from the extended sequence number and the node address are four types of “00”, “01”, “10”, and “11”. It is. Therefore, the control unit 20 identifies a plurality of wireless terminal devices by dividing them into groups for each wireless terminal device having the same lower 2 bits of the node address based on the mask bit and the node address. When the lower 2 bits of the mask bit are 1, the plurality of wireless terminal devices are divided into four groups.

  The value of the mask bit (the number of bits that become 1 of the mask bit) is changed according to the number of wireless terminal devices that can be connected to the wireless relay device 1 that transmits a beacon. In IEEE 802.15.4, it is defined that a maximum of seven node addresses are stored in one beacon. Therefore, the value of the mask bit is determined according to the total number of wireless terminal devices and a multiple of seven.

  When the calculated first calculated value matches the second calculated value, the control unit 20 determines that the received beacon is a beacon addressed to the group to which the self belongs.

  The storage unit 21 is composed of a non-volatile memory that can be electrically erased and rewritten, such as a magnetic or optical recording medium or a semiconductor, and is provided in the wireless terminal device 2 or is detachable. It is to be attached. For example, FeRAM (Ferroelectric Random Access Memory), MRAM (Magneto resistive Random Access Memory), OUM (phase change recording memory by chalcogenide alloy), etc. can be mentioned. The storage unit 21 stores in advance various programs executed by the control unit 20 and various tables and data used in these programs.

  The address memory 22 is composed of a nonvolatile memory that can be electrically erased and rewritten. The address memory 22 stores terminal identification information (node address) for identifying the wireless terminal device 2 itself, and the address memory 22 functions as an identification information storage unit.

  The activation timer 23 is a timer that times the activation timing (activation time) of the wireless reception unit 27 calculated by the control unit 20, and outputs an activation timing signal indicating that the activation timing has been reached to the control unit 20.

  The power control unit 24 controls the power supply of the entire wireless terminal device 2 in accordance with an instruction from the control unit 20, and supplies power from the battery B to each unit in the wireless terminal device 2.

  The battery B is, for example, a primary battery such as an alkaline battery or a manganese battery, or a secondary battery such as a nickel cadmium battery, a nickel hydrogen battery, or a lithium ion battery.

  The display control unit 25a displays various information on the display unit 25b in accordance with the display instruction input from the control unit 20.

  The display unit 25b is configured by an LCD (Liquid Crystal Display), an EL (Electro Luminescence) display, or the like, and displays various screens on the display in accordance with a signal input from the display control unit 25a.

  The wireless transmission unit 26 includes a modulation circuit, an RF (Radio Frequency) circuit, and the like, adjusts the transmission power of the packet, encodes data to be transmitted in accordance with an instruction from the control unit 20, and transmits the packet. The packet is modulated, and the packet is transmitted to the wireless relay device 1 via the antenna 29.

  The wireless reception unit 27 includes a demodulation circuit, an RF circuit, and the like, and is obtained by adjusting the reception sensitivity of the packet, demodulating the packet received via the antenna 29, and analyzing the demodulated packet. The data is output to the control unit 20.

  The SW 28 is provided between the antenna 29 and the wireless transmission unit 26 or the wireless reception unit 27, and transmits a packet from the wireless transmission unit 26 or receives a packet from the antenna 29 in accordance with an instruction from the control unit 20. Switch.

  The antenna 29 transmits a packet according to the set transmission power or receives a packet according to the set reception sensitivity.

Next, the operation of the present embodiment will be described with reference to FIGS.
FIG. 6 shows a flowchart of a beacon transmission process executed in the wireless relay device 1. The process shown in FIG. 6 is executed by the cooperation of the control unit 10 and each unit in the wireless relay device 1 and is executed while power is being supplied to the wireless relay device 1. is there.
In the present embodiment, the number of node addresses stored in the terminal information memory 12 does not exceed 56.

  First, the control unit 10 determines whether or not a packet including a node address has been received from the wireless terminal device 2 via the wireless reception unit 15 (step S1). When the packet including the node address is received (step S1; YES), the control unit 10 stores the node address included in the received packet in the terminal information memory 12 (step S2), and returns to the process of step S1.

  When a packet including a node address has not been received (step S1; NO), the control unit 10 depends on the number of node addresses stored in the terminal information memory 12, that is, the number of connectable wireless terminal devices. The mask bit value is set (steps S3 to S6).

  When the number of node addresses is 14 or less, the control unit 10 sets the value indicated by the mask bit to 1 (the lower 1 bit of the mask bit is 1) (step S4). By step S4, a maximum of 14 wireless terminal devices are divided into two groups whose lower 1 bit of the node address is “0” or “1”.

  When the number of node addresses is 15 or more and 28 or less, the control unit 10 sets the value indicated by the mask bit to 3 (the lower 2 bits of the mask bit are 1) (step S5). In step S5, a maximum of 28 wireless terminal devices are divided into four groups whose lower 2 bits of the node address are “00”, “01”, “10”, and “11”.

  When the number of node addresses is 29 or more, the control unit 10 sets the value indicated by the mask bit to 7 (the lower 3 bits of the mask bit are 1) (step S6). By step S6, a maximum of 56 wireless terminal devices having node addresses with lower 3 bits of “000”, “001”, “010”, “011”, “100”, “101”, “110”, “111” Divide into 8 groups.

  After setting the mask bit, the control unit 10 increments the extension sequence number (step S7), and generates a beacon packet including the set mask bit and the extension sequence number (step S8).

  The controller 10 determines whether or not a beacon transmission timing signal is input from the beacon transmission timer 13 (step S9). When the beacon transmission timing signal is not input (step S9; NO), the control unit 10 returns to the process of step S9.

  When the beacon transmission timing signal is input (step S9; YES), the control unit 10 causes the wireless transmission unit 14 to transmit the generated beacon via the antenna 19 (step S10), clears the beacon transmission timer, and transmits the beacon. Timing of the transmission interval is started (step S11).

  The controller 10 determines whether or not a data request has been received from the wireless terminal device 2 via the wireless receiver 15 (step S12).

  When the data request has not been received (step S12; NO), the control unit 10 determines whether or not a preset time (predetermined time) has elapsed since the time measured by the beacon transmission timer (step S13). When the predetermined time has not elapsed (step S13; NO), the control unit 10 returns to the process of step S12, and when the processing time has elapsed (step S13; YES), the control unit 10 returns to the process of step S1.

  When the data request is received (step S12; YES), the control unit 10 generates data addressed to the wireless terminal device 2 that has transmitted the data request, transmits the data (step S14), and performs the process of step S1. Return.

  As described above, the wireless relay device 1 determines the mask bits indicating the total number of groups to which the wireless terminal devices belong in accordance with the number of wireless terminal devices 2 that can communicate, and transmits a beacon including the mask bits and the extended sequence number. It can be periodically transmitted to the wireless terminal device 2.

  FIG. 7 shows a flowchart of beacon reception processing executed in the wireless terminal device 2. Note that the processing shown in FIG. 7 is executed by the cooperation of the control unit 20 and each unit in the wireless terminal device 2, and is executed while power is being supplied to the wireless terminal device 2. is there.

  The control unit 20 generates a packet including its own node address stored in the address memory 22, and transmits the packet to the wireless relay device 1 via the wireless transmission unit 26 (step S21).

  The control unit 20 searches for a beacon periodically transmitted from the wireless relay device 1 (beacon search) in order to secure a wireless circuit with the wireless relay device 1 (step S22). When the beacon search is completed and a wireless circuit is secured with the wireless relay device 1, the control unit 10 executes an activation timing calculation process described later (step S23).

  When the beacon is received by the wireless receiving unit 27 (step S24), the control unit 10 determines whether the beacon is addressed to the group to which the control unit 10 belongs based on the beacon analysis result by the wireless receiving unit 27 (step S25).

  In step S25, the extended sequence number and the mask bit are extracted from the received beacon. Then, it is determined whether or not the first calculated value calculated by the extended sequence number and the mask bit included in the beacon matches the second calculated value calculated by the own node address and the mask bit. When the first calculated value and the second calculated value match, it is determined that the received beacon is a beacon addressed to the group to which the self belongs.

  When the received beacon is not a beacon addressed to the group to which the beacon belongs (step S25; NO), the control unit 20 returns to the process of step S22.

  When the received beacon is a beacon addressed to the group to which the self belongs (step S25; YES), the control unit 20 determines whether or not the own node address is included in the PA field of the received beacon (step S26). ).

  When the own beacon address is not included in the PA field of the received beacon (step S26; NO), the control unit 20 proceeds to the process of step S28.

  When the own beacon address is included in the PA field of the received beacon (step S26; YES), the control unit 20 executes a data reception process (step S27). The data reception process in step S27 is a process of transmitting a data request packet indicating a data transmission request to the wireless relay device 1 and receiving a data packet transmitted from the wireless relay device 1 in response to the packet.

  Control part 10 performs starting timing calculation processing after Step S26; NO or after Step S27 (Step S28), and returns to processing of Step S24.

  FIG. 8 shows a flowchart of the activation timing calculation process. Note that the processing shown in FIG. 8 is executed by cooperation between the control unit 20 and each unit in the wireless terminal device 2.

  The control part 20 sets the time which received the beacon from the radio relay apparatus 1 to T (step S31), and sets the beacon transmission interval contained in the received beacon to SFI (step S32).

  Further, the control unit 20 sets the extended sequence number included in the beacon payload of the received beacon to SCN (step S33), and sets the mask bit to M (step S34). Furthermore, the control unit 20 sets its own node address to ADDR (step S35).

  The control unit 20 sets the AND value of SCN and M to SCN, and sets the AND value of ADDR and M to ADDR (step S36). The SCN set in step S36 is the first calculated value, and ADDR is the second calculated value.

  The control unit 20 determines whether or not ADDR is larger than SCN (step S37). When ADDR is equal to or less than SCN (step S37; NO), the control unit 20 adds ADDR to a value obtained by adding 1 to M and sets a new ADDR (step S38). For example, in step S38, when M is “11” and ADDR is “10”, 1 is added to M to be “100”. Then, “110” obtained by adding ADDR value “10” to “100” is set as a new ADDR.

  When ADDR is larger than SCN (step S37; YES), or after step S38, control unit 20 sets a value (difference value) obtained by subtracting SCN from ADDR in NSFI (step S39). This NSFI is the number of beacon transmission intervals from when a beacon is received until the next beacon is received. For example, when ADDR is “10” and SCN is “00”, NSFI is “10”. In this case, NSFI is “2” in decimal. Therefore, the number of beacon transmission intervals from when a beacon is received until the next beacon is received, that is, NSFI is set to 2.

  The control unit 20 adds T to a value obtained by multiplying NSFI and SFI (third calculated value), subtracts a preset margin time α, and calculates a start timing (start time) (step S40). The control unit 20 sets the calculated activation timing in the activation timer (step 41), starts timing by the activation timer, and minimizes power supply to each unit such as the wireless transmission unit 26 and the wireless reception unit 27. The wireless terminal device 2 is set in a sleep state by stopping the operations of the wireless transmission unit 26 and the wireless reception unit 27 (step S42).

  The control unit 20 determines whether or not an activation timing signal is input from the activation timer 23 to determine whether or not it is an activation time (step S43). If it is not the activation time (step S43; NO), the control unit 20 returns to the process of step S43.

  If it is the activation time (step S43; YES), the control unit 20 clears the activation timer 23, activates each unit in the sleep state (step S44), and ends this process.

9 and 10 show an operation example of the wireless terminal device performing the beacon reception process.
FIG. 9 shows an example in which the mask bit is 3 (the lower 2 bits are 1), and the lower 2 bits of the extended sequence number are shown. As shown in FIG. 9, the extended sequence number included in the beacon is incremented every time the beacon is transmitted.

  The plurality of wireless terminal devices are divided into four groups based on the node address of each wireless terminal device and the mask bits included in the beacon. For example, a plurality of wireless terminal devices are group 0 for wireless terminal devices whose lower 2 bits of the node address are “00”, group 1 for wireless terminal devices whose lower 2 bits of the node address are “01”, and lower 2 bits of the node address. Can be divided into group 2 and wireless terminal devices whose lower 2 bits of the node address are “11” into group 3.

  The wireless terminal devices belonging to group 0 receive a beacon whose extended sequence number value extracted by the mask bits is “00”, and receive beacons with three extended beacon transmission intervals (extended sequence numbers 01, 10, 11). During the transmission period). Similarly to group 0, wireless terminal apparatuses belonging to groups 1, 2, and 3 receive beacons whose extended sequence number values extracted by mask bits are “01”, “10”, and “11”, respectively. The sleep state is entered during three beacon transmission intervals.

  Therefore, it is not necessary for the wireless terminal device 2 to receive all beacons periodically transmitted from the wireless relay device 1, and it is only necessary to receive beacons transmitted once every four times.

  FIG. 10 shows an example in which the mask bit is F (lower 4 bits are 1), and shows the lower 4 bits of the extended sequence number. As shown in FIG. 10, the extended sequence number included in the beacon is incremented every time the beacon is transmitted.

  The plurality of wireless terminal devices are divided into 16 groups by the node address of each wireless terminal device and the mask bits included in the beacon. For example, a plurality of wireless terminal devices are group 0 for wireless terminal devices whose lower 4 bits of node address are “0000”, group 1 for wireless terminal devices whose lower 4 bits of node address are “0001”, and lower 4 bits of node address. The wireless terminal device having “0010” is divided into group 2,..., And the wireless terminal device having the lower 4 bits of the node address “1111” is divided into group F (15).

  A wireless terminal device belonging to group 0 receives a beacon whose extended sequence number value extracted from the mask bits is “0000”, and transmits a beacon of 15 beacon transmission intervals (a beacon whose extended sequence number is 0001 to 1111). During the sleep period). Similarly to group 0, the wireless terminal devices belonging to groups 1 to F each receive a beacon in which the value of the extended sequence number extracted by the mask bit matches the value of the node address, and during the 15 beacon transmission intervals. , Go to sleep.

  Therefore, it is not necessary for the wireless terminal device 2 to receive all beacons periodically transmitted from the wireless relay device 1, and it is only necessary to receive beacons transmitted once every 16 times.

  As described above, the wireless terminal device 2 can calculate the timing for starting the wireless reception unit using the extended sequence number, the mask bit, and the node address as the group identification information, and the wireless terminal device 2 is in the sleep state until the calculated timing. The operation of the receiver can be stopped. Accordingly, unnecessary beacon standby reception is eliminated, power consumption can be reduced, and power saving can be achieved.

  In addition, the wireless terminal device 2 can determine the beacon addressed to the group to which the wireless terminal device 2 belongs based on the extended sequence number, the mask bit, and the node address. Data can be received if its own node address is included.

It is a schematic block diagram of a radio | wireless communications system. It is a schematic block diagram of a radio relay apparatus. It is a figure which shows the example of a beacon format. It is a schematic block diagram of a radio | wireless terminal apparatus. It is a figure which shows the example of an extended sequence number, a mask bit, and a node address. It is a flowchart of the beacon transmission process performed in a radio relay apparatus. It is a flowchart of the beacon reception process performed in a wireless terminal device. It is a flowchart of a starting timing calculation process. It is a figure which shows the operation example of the radio | wireless terminal apparatus which is performing the beacon reception process. It is a figure which shows the operation example of the radio | wireless terminal apparatus which is performing the beacon reception process.

Explanation of symbols

1 wireless relay device 2 wireless terminal device 3 wired network 10 control unit 11 storage unit 12 terminal information memory 13 beacon transmission timer 14 wireless transmission unit 15 wireless reception unit 16 SW
17 Wired I / F
18 Buffer 19 Antenna 20 Control Unit 21 Storage Unit 22 Address Memory 23 Start-up Timer 24 Power Supply Control Unit 25a Display Control Unit 25b Display Unit 26 Radio Transmitter 27 Radio Receiver 28 SW
29 Antenna A Wireless communication system B Battery B1 MAC header area B2 MAC payload area B21 SS
B22 GTS field B23 PA field B24 Beacon payload B24a Extended sequence number B24b Mask bit B3 MFR area

Claims (8)

In a wireless terminal device including a receiving unit that receives a beacon,
The beacon is
Including group identification information indicating a group to which the wireless terminal device to be received by the beacon belongs,
An identification information storage unit in which terminal identification information for identifying itself is stored;
Based on the group identification information and the terminal identification information included in the beacon received by the reception unit, the control unit calculates the timing for starting the reception unit and stops the operation of the reception unit until the calculated timing When,
Providing
A wireless terminal device. The group identification information is
A sequence number that increases with each beacon transmission, and
Mask information in which a value to be extracted from the sequence number is determined based on the total number of groups that divide a plurality of the wireless terminal devices, and
The controller is
Calculating a difference value between a first calculated value indicating a value extracted from the sequence number using the mask information and a second calculated value indicating a value extracted from the terminal identification information using the mask information; Calculating a third calculated value indicating a value obtained by multiplying the set interval for transmitting the beacon by the difference value, until the timing based on the time obtained by adding the third calculated value to the time when the beacon is received; Stopping the operation of the receiver,
The wireless terminal device according to claim 1. The controller is
Based on the group identification information and the terminal identification information, determining that the beacon received by the receiving unit is a beacon addressed to a group to which the self belongs,
The wireless terminal device according to claim 1, wherein: The beacon is
Including terminal identification information of the wireless terminal device to be data-transmitted;
The controller is
If the beacon received by the receiving unit is a beacon addressed to a group to which the self belongs, if the beacon contains its own terminal identification information, receiving data by the receiving unit;
The wireless terminal device according to claim 3. A transmitter that periodically transmits a beacon to a wireless terminal device;
A said wireless terminal group indicates to group identification information belonging to the reception target of the beacon, the beacon including group identification information for calculating the timing of starting the reception unit of the wireless terminal device belonging to the group And a control unit that causes the transmission unit to transmit the generated beacon to the wireless terminal device;
A wireless relay device comprising: A terminal information storage unit storing information for each wireless terminal device capable of communication;
The group identification information is
A sequence number that increases with each beacon transmission, and
Mask information in which a value to be extracted from the sequence number is determined based on the total number of groups that divide a plurality of the wireless terminal devices, and
The controller is
Determining the mask information according to the number of the wireless terminal devices stored in the terminal information storage unit;
The wireless relay device according to claim 5. Computer
Receiving means for receiving a beacon including group identification information indicating a group to which a wireless terminal device to be received belongs;
Based on the group identification information included in the received beacon and the terminal identification information for identifying itself, the timing for starting the reception function is calculated, and the control means for stopping the operation of the reception function until the calculated timing,
Program to function as. Computer
A transmission means for periodically transmitting a beacon to a wireless terminal device;
A said wireless terminal group indicates to group identification information belonging to the reception target of the beacon, the beacon including group identification information for calculating the timing of starting the reception unit of the wireless terminal device belonging to the group Control means for transmitting the generated beacon to the wireless terminal device by the transmission unit,
Program to function as.

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