JP6681801B2 - Communication device, communication method, and computer program - Google Patents

Description

  The present invention relates to a communication device, a communication method, and a computer program.

  Conventionally, for example, the IEEE 802.11 series is known as a communication standard of a wireless LAN (Local Area Network). 2. Description of the Related Art As an IEEE 802.11 series wireless LAN communication device, a communication device that is in a sleep state only when a transmission buffer is empty is known (for example, see Non-Patent Document 1).

Hsiang-Ho Lin; Hung-Yu Wei; Rath Vannithamby, “DeepSleep: IEEE 802.11 enhancement for energy-harvesting Machine-to-Machine communications,” IEEE Global Communications Conference (GLOBECOM), 2012.

  In the above-described conventional technique, the communication device is in the sleep state only when the transmission buffer is empty (that is, only when there is no data transmission schedule), but is in the awake state at other times. Power could be wasted when the communication device was awake.

  The present invention has been made in consideration of such circumstances, and a communication device, a communication method, and a computer program capable of saving power of the communication device when there is a data transmission schedule of the communication device. The challenge is to provide.

(1) According to one aspect of the present invention, an RF unit that transmits and receives an RF (Radio Frequency) signal via an antenna through an RF channel, a transmission schedule timing determination unit that determines a transmission schedule timing of the RF signal, and the transmission schedule. Based on an RF signal received by the RF channel by the power control unit that stops the power supply to the RF unit during at least a part of the waiting period until the timing , the RF channel is vacant. The power supply control unit supplies power to the RF unit for a minimum first period or more during which the carrier sense unit checks the availability of the RF channel in the standby period. The power supply control unit performs power supply to the RF unit during the first period of a plurality of times during the standby period, and the transmission scheduled time The power supply control unit determines the scheduled transmission timing based on the time when the carrier sense unit detects that the busy RF channel is no longer in the busy state. In the above, the power supply OFF continuation period and the power supply ON continuation period having a length of the first period or more are alternately repeated a plurality of times, and the carrier sense unit performs a plurality of times in the same RF channel in the standby period. A communication device for checking the availability of an RF channel in the first period .
( 2 ) In one aspect of the present invention, in the communication device according to ( 1 ), the power supply control unit supplies power to the RF unit at least at the first period at the end of the standby period. The unit transmits the RF signal through the RF channel at the scheduled transmission timing when the carrier sense unit determines that the RF channel is idle in the first period at the end of the waiting period. On the other hand, when the carrier sensing unit determines that the RF channel is not idle in the first period at the end of the waiting period, the RF signal is not transmitted through the RF channel at the scheduled transmission timing. , A communication device.

(6) In one aspect of the present invention, an RF unit that transmits and receives an RF (Radio Frequency) signal via an RF channel via an antenna, a transmission scheduled timing determination unit that determines transmission scheduled timing of the RF signal, and the RF unit. On the basis of the RF signal received by the RF channel, based on the packet length of the packet as a result of analysis by the header analysis unit that analyzes the header of the packet transmitted by the other communication terminal on the RF channel. Power control for stopping the power supply to the RF unit during at least a part of a period from the start of reception of the packet to the end of reception of the packet in the standby period until the scheduled transmission timing. And a communication unit.

One aspect of the present invention is a communication method of a communication device including an RF unit that transmits and receives an RF (Radio Frequency) signal through an RF channel via an antenna, wherein the communication unit receives the RF unit through the RF channel. Based on the RF signal, a carrier sense step for checking the vacancy of the RF channel, a transmission scheduled timing determining step for the communication apparatus to determine a scheduled transmission timing of the RF signal, and the communication apparatus for the scheduled transmission timing. Power supply control step of stopping the power supply to the RF unit for at least a part of the standby period up to, the power supply control step includes the carrier sense step in the RF channel in the standby period. Power is supplied to the RF unit for at least the first period for checking the vacancy of the In the standby period, power is supplied to the RF unit a plurality of times during the standby period, and in the transmission scheduled timing determination step, the RF channel that was in the busy state is no longer in the busy state. Determines the scheduled transmission timing based on the time detected by the carrier sense step, and the power supply control step has a power supply off continuation period and a length of the first period or more in the standby period. A power supply ON continuation period is alternately repeated a plurality of times, and the carrier sensing step is a communication method in which during the waiting period, the vacancy of the RF channel is checked a plurality of times during the first period in the same RF channel .

(8) One aspect of the present invention is a communication method for a communication device including an RF unit that transmits and receives an RF (Radio Frequency) signal through an RF channel via an antenna, wherein the communication device plans to transmit the RF signal. A transmission scheduled timing determining step for determining timing, and a header for the communication device to analyze a header of a packet transmitted by another communication terminal through the RF channel, based on an RF signal received by the RF unit through the RF channel. The analysis step and the communication device, based on the packet length of the packet of the analysis result of the header analysis step, during the waiting period until the scheduled transmission timing, from the start of reception of the packet to the end of reception of the packet Power control step of stopping the power supply to the RF section for at least a part of the period up to It is a communication method including the.

One aspect of the present invention includes a transmission schedule timing determining function for determining a transmission schedule timing of the RF signal in a computer of a communication device including an RF unit that transmits and receives an RF (Radio Frequency) signal via an antenna via an RF channel. Based on an RF signal received by the RF channel by the RF unit , a power control function of stopping the power supply to the RF unit during at least a part of the waiting period until the scheduled transmission timing. A computer program for realizing a carrier sense function for checking channel vacancy, wherein the power supply control function is a minimum number for the carrier sense function to check the RF channel vacancy during the waiting period. Power is supplied to the RF unit for one period or more, and the power supply control function operates in the standby period. The carrier sense function detects that the RF channel that was in the busy state is no longer in the busy state by supplying power to the RF unit during the first period of a plurality of times The scheduled transmission timing is determined based on the determined time, and the power supply control function sets a power supply OFF continuation period and a power supply ON continuation period having a length of the first period or more in the standby period. The carrier sense function is a computer program which alternately repeats a plurality of times to check the vacancy of the RF channel in the first period of a plurality of times in the same RF channel in the waiting period .

(10) According to one aspect of the present invention, a transmission schedule timing determination unit that determines a transmission schedule timing of the RF signal to a computer of a communication device including an RF unit that transmits and receives an RF (Radio Frequency) signal via an RF channel via an antenna. A function, a header analysis function for analyzing a header of a packet transmitted by the other communication terminal via the RF channel based on an RF signal received by the RF unit via the RF channel, and an analysis result of the header analysis function. Based on the packet length of the packet, at least a part of the waiting period up to the scheduled transmission timing from the start of reception of the packet to the end of reception of the packet is the power to the RF unit. It is a computer program for realizing a power supply control function of stopping supply.

  According to the present invention, it is possible to save the power of the communication device when the data transmission of the communication device is scheduled.

It is a figure which shows the structural example of the communication apparatus 1 which concerns on one Embodiment. It is explanatory drawing of the example 1 of the communication method which concerns on one Embodiment. It is explanatory drawing of the stop example of the electric power supply which concerns on one Embodiment. It is explanatory drawing of the example 2 of the communication method which concerns on one Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, an IEEE 802.11 series wireless LAN will be described as an example of a wireless communication network.

  FIG. 1 is a diagram illustrating a configuration example of a communication device 1 according to an embodiment. The communication device 1 is an IEEE 802.11 series wireless LAN communication device. For example, the communication device 1 is a terminal device of an IEEE 802.11 series wireless LAN. The communication device 1 is a communication device having a function of an IEEE 802.11 series wireless LAN terminal device, and may be, for example, a mobile communication terminal device such as a smartphone or a tablet computer (tablet PC), or It may be a stationary communication terminal device (for example, a stationary personal computer, a server computer, a home gateway, etc.).

  1, the communication device 1 includes an antenna 11, an RF (Radio Frequency) unit 12, a baseband unit 14, an application unit 16, a transmission scheduled timing determination unit 17, and a power supply 18. , And a power supply control unit 19.

  The RF unit 12 transmits / receives an RF signal via an antenna 11 via an RF (radio frequency) channel. The RF unit 12 modulates the baseband signal input from the baseband unit 14 into an RF signal, and the RF signal is transmitted by the antenna 11. Further, the RF unit 12 demodulates the RF signal received by the antenna 11 into a baseband signal and outputs the baseband signal to the baseband unit 14. The RF unit 12 includes an amplifier, a filter, a quadrature modulator, a quadrature demodulator, and the like.

  The RF unit 12 includes a carrier sense unit 13. The carrier sense unit 13 checks the availability of the RF channel (executes carrier sense) based on the RF signal received by the RF unit 12 via the RF channel. The carrier sense unit 13 determines whether the RF channel is idle (idle state) or the RF channel is not idle (busy state).

  The baseband unit 14 performs various processes in the baseband. The baseband unit 14 generates a baseband signal from the transmission data signal input from the application unit 16 and outputs the baseband signal to the RF unit 12. The baseband unit 14 also generates a reception data signal from the baseband signal input from the RF unit 12, and outputs the reception data signal to the application unit 16. The baseband unit 14 includes, for example, a digital-analog (D-A) converter, an analog-digital (A-D) converter, and an arithmetic processing device such as a memory and a digital signal processor (DSP). In addition, the function of the baseband unit 14 is realized by digital signal processing.

  The baseband unit 14 includes a header analysis unit 15. The header analysis unit 15 analyzes the header of the packet transmitted by the other communication terminal via the RF channel, based on the baseband signal input from the RF unit 12. The packet header includes information indicating the length of the packet (packet length).

  The application unit 16 outputs a data signal (transmission data signal) transmitted by the application to the baseband unit 14. Further, the application unit 16 receives and processes the received data signal input from the baseband unit 14 by the application.

  The transmission scheduled timing determination unit 17 determines the transmission scheduled timing of the RF signal. The power supply 18 supplies electric power to each unit of the communication device 1. The power supply controller 19 controls power supply by the power supply 18. The power supply control unit 19 suspends the power supply to the RF unit 12 during at least a part of the standby period until the scheduled transmission timing determined by the scheduled transmission timing determination unit 17.

  Next, an example of the communication method and the operation of the communication device 1 according to the present embodiment will be described.

(Example 1 of communication method)
FIG. 2 is an explanatory diagram of Example 1 of the communication method according to the present embodiment. FIG. 2 shows one RF channel among the RF channels available to the communication device 1. Hereinafter, with reference to FIG. 2, a communication method example 1 and an operation example of the communication device 1 according to the present embodiment will be described. Although one RF channel shown in FIG. 2 will be described here, the same applies to other RF channels. In the following description, the slot time is the time corresponding to one slot. Moreover, one slot has a time length corresponding to the preamble length of the PHY (physical) layer. For example, in the case of the IEEE802.11a1 communication standard, the short preamble length of the PHY (physical) layer is 8 us (microseconds), and the time length of one slot is 9 us.

(Step S1) The carrier sense unit 13 of the communication device 1 checks the availability of the RF channel. As a result, in the example of FIG. 2, the RF channel that was busy was no longer busy at slot time Ta. The carrier sense unit 13 notifies the scheduled transmission timing decision unit 17 that the busy RF channel is no longer busy at the slot time Ta.

(Step S2) The scheduled transmission timing determining unit 17 of the communication device 1 determines a scheduled transmission timing that is a timing at which the RF signal is scheduled to be transmitted by the RF channel. The scheduled transmission timing is a slot represented by the following equation from a slot time Ta when the RF channel in the busy state is no longer in the busy state, a DIFS (Distributed Inter Frame Space) time, and a backoff (backoff) time r. It is determined at time Tss.
Slot time Tss = time Ta + DIFS time + back-off time r
The DIFS time is a time specified by the communication standard of the IEEE 802.11 series. The back-off time r is randomly selected from the time range specified by the communication standard of the IEEE 802.11 series. According to the above formula, the scheduled transmission timing is determined to be the slot time Tss when the total time of the DIFS time and the backoff time r has elapsed from the slot time Ta.

  The transmission scheduled timing determination unit 17 randomly selects the backoff time r from the time range defined by the IEEE 802.11 series communication standard. The transmission scheduled timing determination unit 17 determines the time Tss when the total time of the DIFS time and the backoff time r has elapsed from the slot time Ta notified from the carrier sense unit 13 as the transmission scheduled timing. The scheduled transmission timing determining unit 17 notifies the baseband unit 14 and the power supply control unit 19 of the determined scheduled transmission timing slot time Tss.

(Step S3) The power supply control unit 19 of the communication device 1 supplies power to the RF unit 12 for at least a part of the standby period until the slot time Tss of the scheduled transmission timing notified from the scheduled transmission timing determination unit 17. Stop the supply.

(Example of stopping power supply)
Here, an example of stopping the power supply to the RF unit 12 will be described. FIG. 3 is an explanatory diagram of an example of stopping the power supply according to the present embodiment. In the example of FIG. 3, the power supply control unit 19 turns on (power is supplied) and off (power is not supplied) the power supply to the RF unit 12 in the waiting period from the slot time Ta to the slot time Tss at the scheduled transmission timing. ) And are repeated alternately. The length of the period in which the power supply continues to be on (power supply on duration) and the length of the period in which the power supply remains off (power supply off duration) may be the same or different. Good. Further, the length of the power supply ON duration may be a length of one slot or a length of a plurality of slots. In addition, the length of the power supply off continuation period may be the length of one slot or may be the length of a plurality of slots.

  In addition, the length of the power supply ON duration may be equal to or longer than the minimum length (first period) for the carrier sense unit 13 to check the availability of the RF channel (execute the carrier sense). As a result, the carrier sense unit 13 can check the vacancy of the RF channel (perform carrier sense) during one power supply ON duration.

  Further, as illustrated in FIG. 3, the power supply control unit 19 supplies the power to the RF unit 12 at least for the first period at the end of the standby period from the slot time Ta to the slot time Tss of the scheduled transmission timing. You can go. Thereby, the carrier sense unit 13 can check the availability of the RF channel (execute the carrier sense (CS)) immediately before the slot time Tss of the scheduled transmission timing.

In the example of FIG. 3 described above, the ON and OFF of the power supply to the RF unit 12 are alternately repeated in the standby period from the slot time Ta to the slot time Tss at the scheduled transmission timing, but the present invention is not limited to this. However, the power supply to the RF unit 12 may be stopped during at least a part of the waiting period. For example, the power supply to the RF unit 12 may be stopped during the entire waiting period. Further, for example, power may be supplied to the RF unit 12 only in the last one slot of the standby period, and power supply to the RF unit 12 may be stopped in a period other than the last one slot in the standby period. By supplying power to the RF unit 12 at least in the last one slot of the waiting period, at least immediately before the slot time Tss of the scheduled transmission timing, the vacancy of the RF channel is checked (carrier sense is performed). You can
The above is the description of the example of stopping the power supply to the RF unit 12.

(Step S4) The baseband unit 14 of the communication device 1 starts the packet transmission process at the slot time Tss of the scheduled transmission timing. The packet is a packet input from the application unit 16 and stored in the transmission buffer in the baseband unit 14. When the baseband unit 14 starts the packet transmission process, the baseband unit 14 generates a baseband signal of the packet and inputs the baseband signal to the RF unit 12. Then, the RF unit 12 modulates the baseband signal of the packet input from the baseband unit 14 into an RF signal, and the RF signal is transmitted by the antenna 11. As a result, the transmission of the RF signal of the packet is started by the RF channel from the slot time Tss of the scheduled transmission timing.

  When the carrier sense unit 13 determines that the RF channel is in the busy state during the waiting period from the slot time Ta to the slot time Tss of the scheduled transmission timing after the slot time Ta, the baseband unit 14 sets the scheduled transmission timing. The slot time Tss may be canceled. Since the slot time Tss at the scheduled transmission timing is canceled, the packet transmission process scheduled to start at the scheduled transmission timing slot time Tss is stopped.

  For example, as shown in FIG. 3, at the end of the waiting period from the slot time Ta to the slot time Tss of the scheduled transmission timing, carrier sense (CS) is executed by the carrier sense unit 13 and the RF channel is in a busy state. When it is determined that there is, the baseband unit 14 cancels the slot time Tss of the scheduled transmission timing. As a result, the transmission process of the packet scheduled to start at the slot time Tss of the scheduled transmission timing is stopped, and therefore the RF unit 12 does not transmit the RF signal through the RF channel even at the scheduled transmission time slot Tss. The occurrence of collision of RF signals in the RF channel can be avoided.

  According to Example 1 of the communication method described above, the power supply to the RF unit 12 is stopped during at least a part of the waiting period until the slot time Tss at the scheduled transmission timing. As a result, the power supply 18 of the communication device 1 can be saved when the data transmission of the communication device 1 is scheduled.

  Further, in the waiting period until the slot time Tss of the scheduled transmission timing, the length of the power supply ON duration is the minimum length for checking the vacancy of the RF channel (performing carrier sensing) (first period). By the above, it is possible to check the vacancy of the RF channel (execute the carrier sense) in one power supply ON duration. As a result, in the standby period until the slot time Tss of the scheduled transmission timing, the power supply to the RF unit 12 is stopped to save the power supply 18, and the carrier sense can be executed. When it is detected by the carrier sense that the RF channel has changed to the busy state, the slot time Tss of the scheduled transmission timing is canceled, so that the collision of the RF signal in the RF channel can be avoided.

In the standby period until the slot time Tss at the scheduled transmission timing, power is supplied to the RF unit 12 in at least the last one slot, so that the RF channel is vacant at least immediately before the slot time Tss at the scheduled transmission timing. Can be checked (carrier sense is executed). As a result, it is possible to more reliably avoid collision of RF signals in the RF channel.
The above is the description of Example 1 of the communication method.

(Example 2 of communication method)
FIG. 4 is an explanatory diagram of Example 2 of the communication method according to the present embodiment. FIG. 4 shows one RF channel among the RF channels available to the communication device 1. Hereinafter, with reference to FIG. 4, a communication method example 2 and an operation example of the communication device 1 according to the present embodiment will be described. Here, one RF channel shown in FIG. 4 will be described, but the same applies to other RF channels. In the following description, the description of slot times and slots is the same as in the above-mentioned communication method example 1. Further, in FIG. 4, the same reference numerals are given to the portions corresponding to the respective steps of FIG. 2, and the description thereof will be omitted.

  Steps S1 and S2 are the same as in the first example of the communication method shown in FIG. 2 described above.

(Step S11) The header analysis unit 15 of the communication device 1 analyzes the header of the packet transmitted by another communication terminal through the RF channel, based on the RF signal received by the RF unit 12 through the RF channel. The packet header includes information indicating the length of the packet (packet length). The header analysis unit 15 recognizes the packet length of the packet based on the information indicating the packet length included in the header of the packet transmitted by the other communication terminal via the RF channel. The header analysis unit 15 notifies the power supply control unit 19 of the packet length of the analysis result packet.

  When the packet length of the analysis result packet is notified from the header analysis unit 15, the power supply control unit 19 starts the reception of the packet in the waiting period until the slot time Tss of the scheduled transmission timing based on the packet length. The power supply to the RF unit 12 is stopped during at least a part of the period from the end to the end of reception of the packet. The length of the power supply off duration may be one slot or a plurality of slots. In the example of FIG. 4, when the header analysis unit 15 notifies the packet length of the packet of the analysis result, the power supply control unit 19 performs the RF unit from the slot time Tc immediately after this notification to the last slot time Td of the packet. The power supply to 12 is stopped.

According to the second example of the communication method described above, in the standby period until the slot time Tss of the scheduled transmission timing, when a packet is transmitted from another communication device via the RF channel, at least a part of the period of the packet is The power supply to the RF unit 12 is stopped. As a result, the power supply 18 of the communication device 1 can be saved when the data transmission of the communication device 1 is scheduled.
The above is the description of Example 2 of the communication method.

  The above-described communication method example 1 and communication method example 2 may be combined and applied. For example, as illustrated in FIG. 3, the power supply control unit 19 alternately turns on and off the power supply to the RF unit 12 in the standby period from the slot time Ta to the slot time Tss of the scheduled transmission timing. repeat. Then, in the power supply on-duration period, the header analysis unit 15 analyzes the header of the packet transmitted by the other communication terminal on the RF channel, based on the RF signal received by the RF unit 12 on the RF channel. Then, when the packet length of the analysis result packet is notified from the header analysis unit 15, the power supply control unit 19 starts from the slot time Tc immediately after the notification of the packet length of the packet, as illustrated in FIG. 4, for example. The power supply to the RF unit 12 is stopped until the last slot time Td of the packet.

  Although the embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and includes design changes and the like within a range not departing from the gist of the present invention.

  For example, in the above-described embodiment, the power supply to the RF unit 12 is stopped, but the power supply to the parts other than the RF unit 12 in the communication device 1 may be stopped.

  Further, in the above-described embodiment, the IEEE 802.11 series wireless LAN has been described as an example of the wireless communication network, but the wireless communication network may be applied to other wireless communication networks.

Further, a computer program for realizing the functions of the communication device 1 described above may be recorded in a computer-readable recording medium, and the program recorded in this recording medium may be read by a computer system and executed. . The "computer system" may include an OS and hardware such as peripheral devices.
The “computer-readable recording medium” is a writable non-volatile memory such as a flexible disk, a magneto-optical disk, a ROM, a flash memory, a portable medium such as a DVD (Digital Versatile Disc), or a built-in computer system. A storage device such as a hard disk.

Further, the "computer-readable recording medium" means a volatile memory (for example, a DRAM (Dynamic) in a computer system that serves as a server or a client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. Random Access Memory)), which also holds the program for a certain period of time.
The program may be transmitted from a computer system that stores the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the "transmission medium" for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line.
Further, the program may be a program for realizing some of the functions described above. Further, it may be a so-called difference file (difference program) that can realize the above-mentioned functions in combination with a program already recorded in the computer system.

DESCRIPTION OF SYMBOLS 1 ... Communication device, 11 ... Antenna, 12 ... RF part, 13 ... Carrier sense part, 14 ... Baseband part, 15 ... Header analysis part, 16 ... Application part, 17 ... Transmission schedule timing determination part, 18 ... Power supply, 19 … Power control unit

Claims (4)

An RF unit for transmitting and receiving an RF (Radio Frequency) signal through an RF channel via an antenna;
A scheduled transmission timing determining unit that determines scheduled transmission timing of the RF signal;
A power supply control unit that stops power supply to the RF unit during at least a part of the standby period until the scheduled transmission timing,
A carrier sense unit for checking the vacancy of the RF channel based on an RF signal received by the RF unit via the RF channel,
In the standby period, the power supply control unit supplies power to the RF unit for a minimum first period or more for the carrier sense unit to check the availability of the RF channel,
The power supply control unit performs power supply to the RF unit in the first period of a plurality of times in the standby period,
The scheduled transmission timing determination unit determines the scheduled transmission timing based on a time when the carrier sense unit detects that the RF channel that was in the busy state is no longer in the busy state,
In the standby period, the power supply control unit alternately repeats a power supply off continuation period and a power supply on continuation period having a length of the first period or more a plurality of times,
The carrier sense unit checks the availability of an RF channel in the first RF cycle a plurality of times in the same RF channel in the standby period.
Communication device. The power supply control unit supplies power to the RF unit at least at the first period at the end of the standby period,
When the carrier sense unit determines that the RF channel is idle in the first period at the end of the waiting period, the RF unit transmits the RF signal by the RF channel at the scheduled transmission timing. On the other hand, when the carrier sense unit determines that the RF channel is not idle in the first period at the end of the waiting period, the RF signal is transmitted by the RF channel at the scheduled transmission timing. Do not send,
The communication device according to claim 1 . A communication method of a communication device comprising an RF unit for transmitting and receiving an RF (Radio Frequency) signal through an RF channel via an antenna,
A carrier sensing step in which the communication device checks the availability of the RF channel based on an RF signal received by the RF unit via the RF channel;
A step of determining a scheduled transmission timing for the communication device to determine a scheduled transmission timing of the RF signal;
The communication device includes a power supply control step of stopping power supply to the RF unit during at least a part of a standby period until the scheduled transmission timing ,
In the standby period, the power supply control step supplies power to the RF unit for a minimum first period or more for the carrier sense step to check the vacancy of the RF channel,
The power supply control step performs power supply to the RF unit during a plurality of first periods in the standby period,
The transmission scheduled timing determination step determines the transmission scheduled timing based on the time when the RF sensing of the busy RF channel is no longer in the busy state is detected by the carrier sense step,
The power supply control step, in the standby period, alternately repeats a power supply off continuation period and a power supply on continuation period having a length of the first period or more, a plurality of times,
In the carrier sensing step, during the waiting period, the same RF channel is checked for vacancy of the RF channel in the first period a plurality of times.
Communication method. In a computer of a communication device including an RF unit that transmits and receives an RF (Radio Frequency) signal through an RF channel via an antenna,
A scheduled transmission timing determining function for determining scheduled transmission timing of the RF signal;
A power supply control function of stopping power supply to the RF unit during at least a part of a standby period until the transmission scheduled timing,
A computer program for realizing a carrier sense function for checking the vacancy of the RF channel based on an RF signal received by the RF unit via the RF channel,
In the standby period, the power supply control function supplies power to the RF unit for a minimum first period or more for the carrier sense function to check the availability of the RF channel,
The power supply control function performs power supply to the RF unit during the first period of a plurality of times in the standby period,
The transmission scheduled timing determination function determines the transmission scheduled timing based on the time when the carrier sense function detects that the RF channel that was in the busy state is no longer in the busy state,
In the standby period, the power supply control function alternately repeats a power supply off continuation period and a power supply on continuation period having a length of the first period or more a plurality of times,
The carrier sense function checks the vacancy of an RF channel in the first period a plurality of times in the same RF channel in the standby period,
Computer program.

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