Communication apparatus, communication method, and program

Abstract

To provide a communication device, a communication method and a program for avoiding the occurrence of a long data transmission disabled time while keeping a time restriction by a regulation.SOLUTION: The communication device 3 according to the embodiment includes a transmission processing unit 331 that executes transmission processing of transmitting data to another communication device via a wireless interface on any of a plurality of channels, and a transmission delay processing unit 332 that delays the transmission processing by the transmission processing unit 331. The transmission delay processing unit calculates an additional delay time in each channel when the second data is transmitted after the first data is transmitted by the transmission processing unit, calculates a cumulative additional delay time in all channels, determines a maximum one of the respective additional delay times and the cumulative additional delay time as a maximum additional delay time, and delays the transmission processing by the transmission processing unit 331 by a length of the maximum additional delay time.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a communication device, a communication method, and a program. [Background technology]

[0002] Conventionally, there has been a technology in which multiple smart meters (communication devices) transfer data (hereinafter also referred to as frames) using a so-called bucket brigade method, in which a specific low-power radio wave in the 920 MHz band is used, for example.

[0003] In Japan, the use of 920MHz band LTE radio is subject to the following restrictions when hopping between channels. First, the time that radio waves can be output on each channel is limited to 360 seconds per hour (hereinafter referred to as per-channel time restriction). Second, the total time that radio waves can be output on all channels is limited to 720 seconds per hour (hereinafter referred to as all-channel time restriction).

[0004] Furthermore, for example, when complying with the IEEE (Institute of Electrical and Electronics Engineers) (registered trademark) 802.15.4 standard, a random backoff is inserted when transmitting a unicast frame. A random delay time is also inserted for each transmitted frame immediately before transmission. A backoff is also inserted when retransmitting a frame. There are also cases where it is desirable to transmit each frame on a different channel. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5376886 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the case of transmitting each frame on a different channel, there is room for improvement in throughput. For example, when many frames are transmitted consecutively, the cumulative radio wave output time for all channels can reach 720 seconds in a short time, resulting in a long downtime during which frames cannot be transmitted due to the time constraints on all channels.

[0007] Therefore, the present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a communication device, a communication method, and a program that can avoid the occurrence of long periods of time during which data transmission is not possible while observing time constraints imposed by regulations. [Means for solving the problem]

[0008] A communication device according to an embodiment includes a transmission processing unit that executes a transmission process for transmitting data to another communication device via a wireless interface on one of a plurality of channels, and a transmission delay processing unit that delays the transmission process by the transmission processing unit. When transmitting second data after transmitting first data by the transmission processing unit, the transmission delay processing unit calculates an additional delay time for each of the channels by: for a channel of interest, a radio wave output time is a time period from the start of the transmission process of the first data to the start of the transmission process of the second data during which radio waves are output to transmit the first data on the channel; a paused time is a time period obtained by subtracting the radio wave output time from the time period from the start of the transmission process of the first data to the start of the transmission process of the second data; and, if a time obtained by multiplying the radio wave output time by a predetermined first coefficient is longer than the paused time, a time period obtained by subtracting the paused time from the time period obtained by multiplying the radio wave output time by the first coefficient is the additional delay time; and, when calculating a cumulative additional delay time for all of the channels, the transmission delay processing unit calculates an additional delay time by subtracting the paused time from the time period obtained by multiplying the radio wave output time by the first coefficient. The cumulative total time for which radio waves are output on all of the channels from the start of the transmission processing of the first data to the start of the transmission processing of the second data is defined as the all-channel cumulative radio wave output time, the time obtained by subtracting the all-channel cumulative radio wave output time from the time from the start of the transmission processing of the first data to the start of the transmission processing of the second data is defined as the all-channel paused time, and if the time obtained by multiplying the all-channel cumulative radio wave output time by a predetermined second coefficient is longer than the all-channel paused time, the time obtained by subtracting the all-channel paused time from the time obtained by multiplying the all-channel cumulative radio wave output time by the second coefficient is defined as the cumulative additional delay time, and the maximum of the additional delay times and the cumulative additional delay time is determined to be a maximum additional delay time, and the transmission processing by the transmission processing unit is delayed by the length of the maximum additional delay time. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing the overall configuration of a communication system according to an embodiment. [Figure 2] FIG. 2 is a functional configuration diagram of the communication device according to the embodiment. [Figure 3] FIG. 3 is an explanatory diagram illustrating an example of processing by the communication device according to the embodiment. [Figure 4] FIG. 4 is a flowchart illustrating processing by the communication device according to the embodiment. [Figure 5] FIG. 5 is a flowchart illustrating processing by the communication device according to the embodiment. [Figure 6] FIG. 6 is a flowchart showing the details of the process in step S3 of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of a communication device, a communication method, and a program according to the present invention will be described with reference to the accompanying drawings. First, the configuration of a communication system S according to the embodiment will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is an overall configuration diagram of the communication system S according to the embodiment. Fig. 2 is a functional configuration diagram of a communication device according to the embodiment.

[0011] The communication system S includes a server 1 and a communication network N. The communication network N is, for example, a wireless multi-hop network. The wireless multi-hop network is a network in which multiple communication devices 3 (nodes) having wireless communication capabilities transfer data (frames) in a so-called bucket brigade manner.

[0012] The communication network N includes an aggregation device 2 and a plurality of communication devices 3. In the communication network N of this embodiment, a communication path is autonomously constructed in accordance with, for example, the communication standard RPL (IPv6 Routing protocol for Low Power and Lossy Networks). Specifically, each communication device 3 selects a parent node from among neighboring communication devices 3 depending on the quality of wireless communication with the neighboring communication device 3. Furthermore, a communication device 3 near the aggregation device 2 can select the aggregation device 2 as its parent node. The communication device 3 is, for example, a smart meter, but is not limited to this and may be any IoT device that configures a wireless multi-hop network.

[0013] The aggregation device 2 transmits the data received from the server 1 to the communication device 3. In addition, the aggregation device 2 transmits the data received from the communication device 3 to the server 1.

[0014] The aggregation device 2 and the server 1 are communicatively connected via a WAN (Wide Area Network), which is a wide area communication network such as a mobile phone network or an optical fiber network. In this embodiment, the server 1 is a computer device that transmits data to the aggregation device 2 in the communication network N and receives data from the aggregation device 2.

[0015] In implementing the present invention, the communication devices to be targeted are not limited to IoT devices that form a wireless multi-hop network, but may be any IoT devices that communicate wirelessly. For example, they may be IoT devices that form a star network, or two IoT devices that perform point-to-point communication.

[0016] The communication device 3 includes a wireless interface 31, a storage unit 32, and a processing unit 33. The wireless interface 31 is an interface for wireless communication with neighboring communication devices 3 and the aggregation device 2 in the communication network N. Any wireless communication method can be used, but for example, FSK (frequency shift keying), which is a low-speed wireless method in the 920 MHz band, or OFDM (Orthogonal Frequency Division Multiplexing), which is a higher-speed wireless method in the 920 MHz band, can be used.

[0017] The storage unit 32 stores various types of information (various programs and various types of data) and is realized by, for example, a random access memory (RAM), a read only memory (ROM), a flash memory, or a hard disk drive (HDD).

[0018] The processing unit 33 executes arithmetic processing to realize various functions of the communication device 3. For example, the processing unit 33 is configured with a processor such as a CPU (Central Processing Unit). In the example of Fig. 2, a transmission processing unit 331 and a transmission delay processing unit 332 are shown as functions of the processing unit 33. In this embodiment, when describing functions other than the functions of the transmission processing unit 331 and the transmission delay processing unit 332, the processing unit 33 will be described as the main operating unit.

[0019] Each function is realized by the processing unit 33 (processor) executing the program stored in the storage unit 32. However, without being limited to this, some or all of these functions may be realized by dedicated hardware circuits (semiconductor integrated circuits, etc.).

[0020] The transmission processing unit 331 executes a transmission process for transmitting data to other communication devices 3 or aggregation devices 2 via the wireless interface 31 on any of a plurality of channels.

[0021] The transmission delay processing unit 332 delays the transmission processing by the transmission processing unit 331. Hereinafter, reference will also be made to FIG. 3, which is an explanatory diagram showing an example of processing by the communication device 3 of the embodiment. Note that "backoff, etc." in FIG. 3 refers to delay processing due to backoff and carrier sense. Furthermore, backoff, carrier sense, and retransmission processing during frame transmission may be performed in accordance with, for example, IEEE802.15.4, Wi-SUN (registered trademark) FAN, Wi-SUN HAN, Threads, etc.

[0022] The transmission delay processing unit 332 performs the following processes (G) and (H) when transmitting second data (frame B) after the transmission processing unit 331 has transmitted first data (frame A).

[0023] (G) Calculation of additional delay time for each channel The transmission delay processing unit 332 performs the following processing for each channel of interest for all channels. The transmission delay processing unit 332 determines the time during which radio waves are output to transmit the first data (frame A) on the channel in question (e.g., 10 ms from time t3 to t4 for channel 2) from the start of the transmission process of the first data (frame A) (time t2) to the start of the transmission process of the second data (frame B) (time t9) as the radio wave output time (EmissionDuration[ch]: radio wave output time on channel ch).

[0024] Furthermore, the transmission delay processing unit 332 determines the time obtained by subtracting the radio wave output time from the time from the start of the transmission process of the first data (frame A) (time t2) to the start of the transmission process of the second data (frame B) (time t9) as the paused time (PauseDuration: for example, for channel 2, 140 ms - 10 ms = 130 ms (FIG. 3(c)).

[0025] In addition, if the time obtained by multiplying the radio wave output time by a predetermined first coefficient is longer than the paused time, the transmission delay processing unit 332 determines the time obtained by subtracting the paused time from the time obtained by multiplying the radio wave output time by the first coefficient as the additional delay time (AdditionalPauseDuration).

[0026] Furthermore, the transmission delay processing unit 332 sets the additional delay time (AdditionalPauseDuration) to 0 when the time obtained by multiplying the radio wave output time by a predetermined first coefficient is shorter than the paused time.

[0027] For example, in the case of channel 2, the time (90 ms) obtained by multiplying the radio wave output time (10 ms) by the first coefficient (for example, 9) is shorter than the paused time (130 ms), so the additional delay time (AdditionalPauseDuration) is set to 0.

[0028] (H) Calculating the cumulative additional delay time for all channels The transmission delay processing unit 332 determines the total time for which radio waves are output on all channels (channels 0 to 5) from the start of the transmission process of the first data (frame A) (time t2) to the start of the transmission process of the second data (frame B) (time t9) as the total radio wave output time for all channels (EmissionDurationAllChannels). In the example of Fig. 3 (b), the total radio wave output time for all channels is (1) (10 ms) + (2) (10 ms) + (3) (10 ms) = 30 ms.

[0029] Furthermore, the transmission delay processing unit 332 determines the all-channel pause time to be the time obtained by subtracting the all-channel cumulative radio wave output time (EmissionDurationAllChannels) from the time from the start of the transmission process of the first data (frame A) (time t2) to the start of the transmission process of the second data (frame B) (time t9). In the example of Fig. 3, as shown in (b), the all-channel pause time is 140 ms - 30 ms = 110 ms.

[0030] In addition, if the time obtained by multiplying the cumulative radio wave output time of all channels (EmissionDurationAllChannels) by a predetermined second coefficient (for example, 4) is longer than the all-channel pause time, the transmission delay processing unit 332 determines the cumulative additional delay time to be the time obtained by multiplying the cumulative radio wave output time of all channels by the second coefficient minus the all-channel pause time.

[0031] Furthermore, the transmission delay processing unit 332 sets the cumulative additional delay time to 0 when the time obtained by multiplying the cumulative all-channel radio wave output time (EmissionDurationAllChannels) by the second coefficient is shorter than the all-channel pause time.

[0032] For example, in the example of Figure 3, the time (120 ms) obtained by multiplying the cumulative radio wave output time of all channels (EmissionDurationAllChannels: 30 ms) by a second coefficient (e.g., 4) is longer than the all-channel pause time (110 ms), so the time (10 ms) obtained by multiplying the cumulative radio wave output time of all channels (30 ms) by the second coefficient (e.g., 4) (120 ms) minus the all-channel pause time (110 ms) is set to the cumulative additional delay time.

[0033] Thereafter, the transmission delay processing unit 332 determines the maximum of each additional delay time and the cumulative additional delay time as the maximum additional delay time (MaxAdditionalPauseDuration), and delays the transmission processing by the transmission processing unit 331 by the length of the maximum additional delay time. In the example of Fig. 3, the maximum additional delay time (MaxAdditionalPauseDuration) is 10 ms.

[0034] Next, the processing by the communication device 3 will be described with reference to Fig. 4 to Fig. 6. Fig. 4 and Fig. 5 are flowcharts showing the processing by the communication device 3 according to the embodiment. Fig. 6 is a flowchart showing the details of the processing in step S3 in Fig. 4.

[0035] In step S1, the transmission processing unit 331 determines whether or not there is a frame to be transmitted, and if Yes, proceeds to step S2, and if No, returns to step S1. For example, in the example of Fig. 3, the transmission processing unit 331 determines that there is a frame to be transmitted at time t9 when frame B was generated.

[0036] In step S2, the transmission processing unit 331 determines whether or not this is the first frame transmission, and if Yes, the process proceeds to step S4, and if No, the process proceeds to step S3.

[0037] In step S301 of step S3 (FIG. 6), the transmission delay processing unit 332 initializes (sets to 0) the maximum additional delay time (MaxAdditionalPauseDuration).

[0038] Next, in steps S302 to S309, the transmission delay processing unit 332 repeatedly executes the process for the index ch of each channel.

[0039] In step S303, the transmission delay processing unit 332 calculates the paused time (PauseDuration) by subtracting the radio wave output time (EmissionDuration[ch]) of the channel of interest from the time (140 ms) from PauseStart (time t2) to the current time (time t9) (Figure 3(c)).

[0040] Next, in step S304, the transmission delay processing unit 332 initializes (sets to 0) the additional delay time (AdditionalPauseDuration).

[0041] Next, in step S305, the transmission delay processing unit 332 determines whether the paused time (PauseDuration) is shorter than N times (N is, for example, 9) the radio wave output time (EmissionDuration[ch]), and if Yes, proceeds to step S306; if No, proceeds to step S307.

[0042] In step S306, the transmission delay processing unit 332 subtracts the paused time (PauseDuration) from N times the radio wave output time (EmissionDuration[ch]) to obtain the additional delay time (AdditionalPauseDuration).

[0043] In step S307, the transmission delay processing unit 332 determines whether the maximum additional delay time (MaxAdditionalPauseDuration) is smaller than the additional delay time (AdditionalPauseDuration), and if Yes, proceeds to step S308, and if No, proceeds to step S309.

[0044] In step S308, the transmission delay processing unit 332 substitutes the value of the additional delay time (AdditionalPauseDuration) into the maximum additional delay time (MaxAdditionalPauseDuration).

[0045] When the processing of steps S302 to S309 is completed for all channels, in step S310, the transmission delay processing unit 332 calculates the pause time for all channels (PauseDuration) by subtracting the cumulative radio wave output time for all channels (EmissionDurationAllChannels) from the time (140 ms) from PauseStart (time t2) to the current time (time t9) (Figure 3(b)).

[0046] Next, in step S311, the transmission delay processing unit 332 subtracts the all-channel pause time (PauseDuration) from M times (M is, for example, 4) the all-channel cumulative radio wave output time (EmissionDurationAllChannels) to obtain the cumulative additional delay time (AdditionalPauseDuration).

[0047] Next, in step S312, the transmission delay processing unit 332 determines whether the maximum additional delay time (MaxAdditionalPauseDuration) is smaller than the cumulative additional delay time (AdditionalPauseDuration), and if Yes, proceeds to step S313, and if No, proceeds to step S314.

[0048] In step S313, the transmission delay processing unit 332 substitutes the value of the cumulative additional delay time (AdditionalPauseDuration) into the maximum additional delay time (MaxAdditionalPauseDuration).

[0049] Next, in step S314, the transmission delay processing unit 332 pauses processing for the maximum additional delay time (MaxAdditionalPauseDuration) (times t9 to t10 in FIG. 3).

[0050] Next, in steps S4 to S6, the transmission delay processing unit 332 repeatedly executes the process for each channel index ch. In step S5, the transmission delay processing unit 332 initializes (sets to 0) the radio wave output time (EmissionDuration[ch]) for the channel of interest.

[0051] When the processing of steps S4 to S6 is completed for all channels, in step S7, the transmission delay processing unit 332 initializes (sets to 0) the cumulative radio wave output time of all channels (EmissionDurationAllChannels) and substitutes the current time for PauseStart.

[0052] Next, in step S8, the transmission delay processing unit 332 calculates the back-off time.

[0053] Next, in step S9, the transmission delay processing unit 332 executes backoff, that is, pauses processing for the backoff time.

[0054] Next, in step S10, the transmission processing unit 331 determines a transmission channel.

[0055] Next, in step S11, the transmission delay processing unit 332 performs carrier sensing.

[0056] Next, in step S12, the transmission delay processing unit 332 determines whether the channel is clear (for example, whether it has recognized that no other communication device has transmitted radio waves on that channel within the last 128 μs), and if Yes, proceeds to step S13; if No, proceeds to step S21.

[0057] In step S13, the transmission processing unit 331 assigns the index of the transmission channel to ch.

[0058] Next, in step S14, the transmission processing unit 331 assigns the current time to EmissionStart.

[0059] Next, in step S15, the transmission processing unit 331 transmits the frame via the wireless interface 31.

[0060] Next, in step S16, the transmission processing unit 331 adds the time from EmissionStart to the current time to the radio wave output time (EmissionDuration[ch]).

[0061] Next, in step S17, the transmission processing unit 331 adds the time from EmissionStart to the current time to the cumulative radio wave output time of all channels (EmissionDurationAllChannels).

[0062] Next, in step S18, the transmission processing unit 331 determines whether the transmitted frame is a unicast frame, and if Yes, the process proceeds to step S19, and if No, the process proceeds to step S20.

[0063] In step S19, the transmission processing unit 331 determines whether or not an ACK (acknowledgement response signal) has been received within a specified time, and if Yes, the process proceeds to step S20, and if No, the process proceeds to step S23.

[0064] In step S20, the transmission delay processing unit 332 pauses processing for the specified inter-frame free time, and then returns to step S1.

[0065] In step S21, the transmission delay processing unit 332 determines whether or not to further perform backoff, and if Yes, the process returns to step S8, and if No, the process proceeds to step S22.

[0066] In step S22, the transmission processing unit 331 determines whether the frame is a unicast frame, and if Yes, the process proceeds to step S23, and if No, the process proceeds to step S24.

[0067] In step S23, the transmission processing unit 331 determines whether or not to retransmit the frame again, and if Yes, the process returns to step S8, and if No, the process proceeds to step S24.

[0068] In step S24, the transmission processing unit 331 discards the transmission frame, and the process returns to step S1.

[0069] (Variation) The first coefficient (N) by which the radio wave output time is multiplied for each channel does not have to be 9. Also, the second coefficient (M) by which the cumulative radio wave output time for all channels is multiplied does not have to be 4.

[0070] For example, N may be set to a value greater than 9 to allow for the possibility that at the end of an hour, a maximum size frame may be sent x times in rapid succession, i.e., a total of (x+1) times.

[0071] For example, when transmitting one frame of the maximum size, the maximum radio wave transmission time, including retransmissions, is set to a. In this case, N should be set to a value equal to or greater than "(Ia) / (W1-a)-1". Here, I and W1 are intended to "keep the cumulative radio wave transmission time per time period I within W1." For example, I may be set to 3600 seconds, and W1 to 360 seconds.

[0072] Similarly, M may be set to a value equal to or greater than "(Ia) / (W2-a)-1", where W2 may be set to 720 seconds.

[0073] For example, when using the IEEE802.15.4 2FSK 100kbps modulation method, the maximum PMDU size is 2047 bytes. When a frame is transmitted with a 15-byte preamble, a 2-byte SFD, and a 2-byte PHY header, the radio transmission time per frame is (2 + 2 + 15 + 2047) × 8 / 100000 = 0.16528 seconds.

[0074] Furthermore, if the number of retransmissions is set to a maximum of seven as specified by IEEE802.15.14, a is 0.16528 × (7 + 1) = 1.32224 seconds. If I is set to 3600 seconds and W1 is set to 360 seconds, and N = "(Ia) / (W1-a)-1", the result is approximately 9.033. Therefore, if N is set to, for example, 9.034, the per-channel time constraint can be reliably met even in the most severe case. Similarly, by calculating and using M in the same way, the all-channel time constraint can be reliably met even in the most severe case.

[0075] As described above, according to this embodiment, the maximum of the additional delay time for each channel and the cumulative additional delay time is determined as the maximum additional delay time, and the transmission processing by the transmission processing unit 331 is delayed by the length of the maximum additional delay time, thereby making it possible to avoid the occurrence of long periods of time during which data transmission is not possible while observing the prescribed time constraints (time constraints for each channel and time constraints for all channels), thereby increasing the average throughput.

[0076] Furthermore, by using multiple channels, it is possible to shorten the delay time compared to when a single channel is used, thereby increasing the average throughput.

[0077] Furthermore, since no restrictions are placed on the backoff time, timing, or retransmission timing, the present invention can be implemented in conjunction with a variety of communication methods including IEEE802.15.4.

[0078] Although an embodiment of the present invention has been described, this embodiment is presented as an example and is not intended to limit the scope of the invention. This novel embodiment can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. This embodiment and its modifications are included within the scope and spirit of the invention, and are also included in the invention described in the claims and their equivalents. [Explanation of symbols]

[0079] 1...server, 2...aggregation device, 3...communication device, 31...wireless interface, 32...storage unit, 33...processing unit, 331...transmission processing unit, 332...transmission delay processing unit, N...communication network, S...communication system

Claims

1. a transmission processing unit that performs a transmission process to transmit data to another communication device via a wireless interface on one of a plurality of channels; a transmission delay processing unit that delays the transmission processing by the transmission processing unit, The transmission delay processing unit When the second data is transmitted after the first data is transmitted by the transmission processing unit, When calculating the additional delay time for each of the channels, With respect to the channel of interest, a radio wave output time is a time period during which radio waves are output to transmit the first data on the channel from a time point at which the transmission process of the first data is started to a time point at which the transmission process of the second data is started; a time obtained by subtracting the radio wave output time from a time from the start of the transmission process of the first data to the start of the transmission process of the second data is set as a paused time; If the time obtained by multiplying the radio wave output time by a predetermined first coefficient is longer than the paused time, the time obtained by subtracting the paused time from the time obtained by multiplying the radio wave output time by the first coefficient is set as the additional delay time; When calculating the cumulative additional delay time for all the channels, a total cumulative radio wave output time of all the channels is defined as a cumulative radio wave output time of all the channels from the start of the transmission process of the first data to the start of the transmission process of the second data; a time obtained by subtracting the all-channel cumulative radio wave output time from a time from the start of the transmission process of the first data to the start of the transmission process of the second data is defined as an all-channel pause time; If the time obtained by multiplying the cumulative radio wave output time of all channels by a predetermined second coefficient is longer than the all-channel pause time, the time obtained by multiplying the cumulative radio wave output time of all channels by the second coefficient minus the all-channel pause time is set as the cumulative additional delay time, determining the maximum of each of the additional delay times and the cumulative additional delay time as a maximum additional delay time; a communication device that delays the transmission process by the transmission processing unit by the length of the maximum additional delay time.

2. The transmission delay processing unit When calculating the additional delay time for each of the channels, With respect to the channel of interest, If the time obtained by multiplying the radio wave output time by the first coefficient is shorter than the paused time, the additional delay time is set to 0. The communication device according to claim 1 .

3. The transmission delay processing unit When calculating the cumulative additional delay time for all the channels, If the time obtained by multiplying the cumulative radio wave output time of all channels by the second coefficient is shorter than the all-channel pause time, the cumulative additional delay time is set to 0. The communication device according to claim 1 .

4. a transmission processing unit that performs a transmission process to transmit data to another communication device via a wireless interface on one of a plurality of channels; a transmission delay processing unit that delays the transmission processing by the transmission processing unit, The transmission delay processing unit When the second data is transmitted after the first data is transmitted by the transmission processing unit, When calculating the additional delay time for each of the channels, With respect to the channel of interest, a radio wave output time is a time period during which radio waves are output to transmit the first data on the channel from a time point at which the transmission process of the first data is started to a time point at which the transmission process of the second data is started; a time obtained by subtracting the radio wave output time from a time from the start of the transmission process of the first data to the start of the transmission process of the second data is set as a paused time; If the time obtained by multiplying the radio wave output time by a predetermined first coefficient is longer than the paused time, the time obtained by subtracting the paused time from the time obtained by multiplying the radio wave output time by the first coefficient is set as the additional delay time; When calculating the cumulative additional delay time for all the channels, a total cumulative radio wave output time of all the channels is defined as a cumulative radio wave output time of all the channels from the start of the transmission process of the first data to the start of the transmission process of the second data; a time obtained by subtracting the all-channel cumulative radio wave output time from a time from the start of the transmission process of the first data to the start of the transmission process of the second data is defined as an all-channel pause time; If the time obtained by multiplying the cumulative radio wave output time of all channels by a predetermined second coefficient is longer than the all-channel pause time, the time obtained by multiplying the cumulative radio wave output time of all channels by the second coefficient minus the all-channel pause time is set as the cumulative additional delay time, determining the maximum of each of the additional delay times and the cumulative additional delay time as a maximum additional delay time; a communication method in which the transmission processing by the transmission processing unit is delayed by the length of the maximum additional delay time.

5. a transmission processing unit that performs a transmission process to transmit data to another communication device via a wireless interface on one of a plurality of channels; A program for causing a transmission delay processing unit to execute processing in a communication device including: a transmission delay processing unit that delays the transmission processing by the transmission processing unit. The transmission delay processing unit When the second data is transmitted after the first data is transmitted by the transmission processing unit, When calculating the additional delay time for each of the channels, With respect to the channel of interest, a radio wave output time is a time period during which radio waves are output to transmit the first data on the channel from a time point at which the transmission process of the first data is started to a time point at which the transmission process of the second data is started; a time obtained by subtracting the radio wave output time from a time from the start of the transmission process of the first data to the start of the transmission process of the second data is set as a paused time; If the time obtained by multiplying the radio wave output time by a predetermined first coefficient is longer than the paused time, the time obtained by subtracting the paused time from the time obtained by multiplying the radio wave output time by the first coefficient is set as the additional delay time; When calculating the cumulative additional delay time for all the channels, a total cumulative radio wave output time of all the channels is defined as a cumulative radio wave output time of all the channels from the start of the transmission process of the first data to the start of the transmission process of the second data; a time obtained by subtracting the all-channel cumulative radio wave output time from a time from the start of the transmission process of the first data to the start of the transmission process of the second data is defined as an all-channel pause time; If the time obtained by multiplying the cumulative radio wave output time of all channels by a predetermined second coefficient is longer than the all-channel pause time, the time obtained by multiplying the cumulative radio wave output time of all channels by the second coefficient minus the all-channel pause time is set as the cumulative additional delay time, determining the maximum of each of the additional delay times and the cumulative additional delay time as a maximum additional delay time; delaying the transmission processing by the transmission processing unit by the length of the maximum additional delay time; program.

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