Communication device, communication method, and program

Abstract

To provide a communication device that performs communication using a more appropriate amount of data per unit time according to the state of wireless communication.SOLUTION: A setting value for the number of divisions of transmission data is calculated based on transmission parameters with a communication device of a transmission destination of the transmission data. The transmission data is divided based on the setting value for the number of divisions. A plurality of transmission units each containing one of multiple pieces of division data output by dividing the transmission data, or composed of exclusive OR of multiple pieces of division data randomly selected from the multiple pieces of division data are generated, and transmitted to the communication device of the transmission destination.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] There are technologies that can prevent a decrease in the amount of data transmitted per unit time even when wireless communication conditions are poor. For example, these technologies use packet coding, dividing the data before transmitting, and switching communication frequencies to prevent a decrease in the amount of data transmitted per unit time.

[0003] Patent Document 1 discloses a technique for transmitting coded packets based on a transmission rate calculated based on a packet loss rate. Patent Document 2 discloses a technique for slowing down or speeding up the data communication speed based on the buffer usage rate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2021 / 060406 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-78065 Summary of the Invention [Problem to be solved by the invention]

[0005] In the wireless technology described above, there is a demand for a technology that performs communication with a more appropriate amount of data per unit time according to the state of wireless communication.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a communication device, a communication method, and a program that solve the above-mentioned problems. [Means for solving the problem]

[0007] According to a first aspect of the invention, a communication device comprises a division number calculation means for calculating a set value for the division number of transmission data based on transmission parameters between the communication device to which the transmission data is to be sent, a division means for dividing the transmission data based on the set value for the division number, and a transmission means for generating a plurality of transmission units each including one of a plurality of divided data output by the division of the transmission data, or each transmission unit consisting of the exclusive OR of a plurality of divided data randomly selected from the plurality of divided data, and sending the transmission units to the destination communication device.

[0008] According to a second aspect of the invention, a communication method calculates a set value for the number of divisions of transmission data based on transmission parameters between the transmission data and a communication device that is a destination of the transmission data, divides the transmission data based on the set value for the number of divisions, generates multiple transmission units each including one of the multiple division data output by the division of the transmission data, or multiple transmission units consisting of the exclusive OR of multiple division data randomly selected from the multiple division data, and transmits them to the destination communication device.

[0009] According to a third aspect of the invention, the program causes a computer of a communication device to function as a division number calculation means that calculates a set value for the number of divisions of transmission data based on transmission parameters between the communication device to which the transmission data is to be sent, a division means that divides the transmission data based on the set value for the number of divisions, and a transmission means that generates multiple transmission units each including one of the multiple division data output by the division of the transmission data, or multiple transmission units consisting of the exclusive OR of multiple division data randomly selected from the multiple division data, and sends them to the destination communication device. [Effects of the Invention]

[0010] According to the present invention, communication can be performed with a more appropriate amount of data per unit time according to the state of wireless communication. [Brief explanation of the drawings]

[0011] [Figure 1]1 is a diagram showing the configuration of a wireless communication system according to an embodiment of the present invention. [Figure 2] 1 is a functional block diagram of a communication device constituting a wireless communication system according to an embodiment of the present invention; [Figure 3] FIG. 10 is a diagram illustrating an outline of processing performed by a transmitting communication device according to the present embodiment. [Figure 4] FIG. 10 is a diagram showing an example of matrix data according to the present embodiment. [Figure 5] FIG. 2 is a diagram illustrating an outline of processing by an encoding unit according to the present embodiment. [Figure 6] 10A and 10B are diagrams illustrating a process of calculating the number of divisions according to a set value of the number of divisions according to the present embodiment. [Figure 7] FIG. 10 is a diagram illustrating an outline of a process for transmitting a transmission packet according to the present embodiment. [Figure 8] FIG. 4 is a diagram showing a processing flow of the communication device according to the present embodiment. [Figure 9] FIG. 1 is a diagram illustrating a minimum configuration of a communication device according to the present embodiment. [Figure 10] FIG. 10 is a diagram showing a processing flow of a communication device with a minimum configuration according to the present embodiment. [Figure 11] FIG. 2 is a diagram illustrating a hardware configuration of a communication device according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] FIG. 1 is a diagram showing the configuration of a wireless communication system according to this embodiment. A wireless communication system 100 according to this embodiment is configured by a wireless communication connection between a communication device 1 and a communication device 2. The communication devices 1 and 2 are connected by wireless communication using a plurality of different frequencies. Specifically, the wireless communication section between the communication devices 1 and 2 can be connected by using each of a first frequency 3a, a second frequency 3b, and a third frequency 3c. The communication devices 1 and 2 switch the frequency to be used in the wireless communication section 3 depending on the communication state. In other words, the communication devices 1 and 2 determine which frequency to use in their communication with each other, the first frequency 3a, the second frequency 3b, or the third frequency 3c, and perform wireless communication using the determined frequency. The communication devices 1 and 2 are each equipped with an antenna for each available frequency.

[0013] FIG. 2 is a functional block diagram of a communication device that constitutes a wireless communication system. Communication device 1 will be described using wireless communication system 100 in Fig. 2 as a device that mainly transmits transmission data. Communication device 2 will be described using wireless communication system 100 in Fig. 2 as a device that mainly receives transmission data transmitted by communication device 1. As shown in Fig. 2, communication device 1 performs the functions of a wired receiving unit 11, a wireless transmitting unit 12, a division number calculating unit 13, and a wireless receiving unit 14.

[0014] The wired receiving unit 11 receives transmission data addressed to the communication device 2 from another device connected to the communication device 1 via a wired network. The wireless transmission unit 12 controls wireless transmission of the received transmission data addressed to the communication device 2 to the communication device 2. The division number calculation unit 13 divides the transmission data based on a set value. The wireless receiving unit 14 receives data wirelessly transmitted from the communication device 2.

[0015] The wireless transmitting unit 12 of the communication device 1 performs the functions of an input rate calculation unit 121 , an allowable rate calculation unit 122 , a transmission rate calculation unit 123 , an encoding unit 124 , a transmission rate control unit 125 , and a transmitting unit 126 . The input rate calculation unit 121 calculates the amount of data received by the wired receiving unit 11 per unit time (input rate). The allowable rate calculation unit 122 calculates the maximum amount of data that can be transmitted per unit time (allowable rate) in wireless communication with the communication device 2. The transmission rate calculation unit 123 identifies the amount of data per unit time (transmission rate) that indicates the smaller value of the input rate and the allowable rate. The encoding unit 124 divides and encodes the transmission data based on the set value of the division number. The transmission rate control unit 125 instructs the transmission rate calculation unit 123 to transmit the transmission data based on the transmission rate calculated by the transmission rate calculation unit 123 . The transmitter 126 transmits the transmission data to the communication device 2 based on an instruction from the transmission rate controller 125. The transmitter 126 switches the frequency of the wireless communication zone in which the transmission data is transmitted.

[0016] The communication device 2 performs the functions of a wireless receiving unit 21, a decoding unit 22, a wired transmitting unit 23, and a wireless transmitting unit 24. The wireless receiving unit 21 receives the transmission data transmitted from the communication device 1. The decoder 22 decodes the transmission data. The wired transmission unit 23 sends the data decoded by the decoding unit 22 to the wired network side. The wireless transmitting unit 24 transmits response data such as an ACK to the communication device 1 when the transmission data is received.

[0017] Communication device 1 and communication device 2 can each be the sender or receiver of transmitted data. That is, when communication device 1 receives data via wireless communication, it performs the functions of communication device 2, and when communication device 2 transmits data via wireless communication, it performs the functions of communication device 1. In the following description, communication device 1 is the sender and communication device 2 is the receiver.

[0018] FIG. 3 is a diagram showing an outline of processing performed by the transmitting communication device. FIG. 4 is a diagram showing an example of matrix data used to calculate the set value of the number of divisions. The division number calculation unit 13 described above acquires the amount of data in the input buffer available in the input buffer (hereinafter referred to as available buffer amount) from the wired receiving unit 11 as information about available buffer space in the input buffer. The division number calculation unit 13 also acquires from the wireless receiving unit 14 the packet loss rate and RTT (Round-Trip Time) for each link of each frequency detected by the communication device 1 in wireless communication with the communication device 2. The division number calculation unit 13 also acquires the input rate (the amount of data received by the wired receiving unit 11 per unit time) from the input rate calculation unit 121. The division number calculation unit 13 acquires an RSSI (Received Signal Strength Indicator) value for each link of each frequency detected by the communication device 1 in wireless communication with the communication device 2. The division number calculation unit 13 calculates a setting value K for the number of divisions of the transmission data based on the acquired available buffer amount, packet loss rate, RTT, input rate, and RSSI value. The information used to calculate the setting value K is one aspect of the transmission parameters between the communication device 1 and the communication device 2, which is the destination of the transmission data.

[0019] More specifically, for example, the division number calculation unit 13 may calculate the input buffer consumption rate based on the amount of free buffer space and the input rate, and use matrix data that stores a K value corresponding to the relationship between the consumption rate and the RSSI value. The input buffer consumption rate may be the average amount of data accumulated in the input buffer per unit time, for example. The division number calculation unit 13 may calculate a numerical value indicating the data input state based on one or more pieces of information selected from the acquired free buffer space, packet loss rate, RTT, and input rate, and calculate the set value K of the division number using matrix data (FIG. 4) that stores a K value corresponding to the relationship between the numerical value and the RSSI value. Alternatively, the division number calculation unit 13 may input the acquired free buffer space, packet loss rate, RTT, input rate, and RSSI value into a predetermined calculation formula for calculating the set value K of the number of divisions of transmission data, and calculate the set value K. The RSSI value indicates a negative value and is expressed in dBm. The closer the RSSI value is to 0, the stronger the received radio wave strength, indicating stable communication. The matrix data shown in Fig. 4 indicates that the lower the RSSI value, the larger the division number setting value K. The matrix data also indicates that the lower the input buffer consumption rate, the larger the division number setting value K.

[0020] The encoder 124 divides the transmission data by a set value K of the division number, and generates a plurality of transmission-unit packets, each including one of the plurality of divided data pieces output by the division, or each consisting of the exclusive OR of a plurality of divided data pieces randomly selected from the plurality of divided data pieces. The encoder 124 instructs the transmission rate controller 125 to transmit the transmission-unit packets in order. At this time, the transmission rate calculator 123 calculates a transmission rate using the input rate acquired from the wired receiver 11, the coding loss rate acquired from the encoder 124, the packet loss rate acquired from the wireless receiver 14, the input rate acquired from the input rate calculator 121, and the allowable rate acquired from the allowable rate calculator 122. When calculating the transmission rate using n pieces of information, such as the input rate, coding loss rate, packet loss rate, and allowable rate, the transmission rate calculator 123 also calculates the transmission rate using n-dimensional matrix data specifying the transmission rates corresponding to the n pieces of information. The transmission rate control unit 125 transmits the packets of the transmission unit generated by the encoding unit 124 to the communication device 2 in order based on the transmission rate.

[0021] FIG. 5 is a diagram showing an outline of processing by the encoding unit. The encoder 124 divides the transmission data stored in the input buffer of the wired receiver 11 based on the set value K of the division number. The example in FIG. 4 shows a case where the set value K=5 and the transmission data is divided into five pieces of divided data a, b, c, d, and e. The encoder 124 generates a random number table T that randomly selects one or more of the divided data a, b, c, d, and e output by division over time. The encoder 124 selects one or more pieces of divided data based on a random number that selects one or more pieces of divided data recorded in the random number table T over time, and generates transmission unit data composed of the exclusive OR (XOR) of the selected divided data. This is called encoding. The encoder 124 generates transmission packets by attaching headers and the like to the generated transmission unit data. The encoder 124 outputs the transmission packets to the transmission rate controller 125.

[0022] FIG. 6 is a diagram showing a process of calculating the number of divisions according to the set value of the number of divisions. 6 shows an overview of the processing performed by the division number calculation unit 13 when the division number setting value K = 3, when the setting value K = 5, and when the setting value K = 7. As shown in FIG. 6, as the division number setting value K increases, the number of packets per transmission unit increases.

[0023] FIG. 7 is a diagram showing an outline of a process for transmitting a transmission packet. As shown in FIG. 7, suppose that communication device 1 divides a certain piece of data into three pieces based on the set value K=3 for the number of divisions. The three pieces of divided data are called divided data a, divided data b, and divided data c. Then, the encoded packets of the transmission unit are transmitted to communication device 2 in the following order, for example: packet (a+b), packet (a+b+c), packet (b+c), packet (a+c), and packet (a). Here, "+" indicates exclusive OR (XOR). For example, packet (a+b) indicates the exclusive OR of divided data a and divided data b.

[0024] In this example, it is assumed that packets (a+b) and (b+c) are lost along the way. In this case, the unknown number of input packets is three: divided data a, divided data b, and divided data c. Based on the received transmission packet (a+b+c), transmission packet (a+c), and transmission packet (a), which contain the three divided data, communication device 2 can determine divided data a, divided data b, and divided data c. In this way, by receiving the packets transmitted using the above-described encoding, and receiving coded transmission unit packets of the same number as the unknown number, communication device 2 can decode all of the divided data.

[0025] FIG. 8 is a diagram showing a processing flow of the communication device. Next, the processing flow of the communication device will be explained step by step. The wireless transmission unit 12 of the communication device 1 detects a link-up by wireless communication connection with the communication device (step S101). The wireless transmission unit 12 instructs the division number calculation unit 13 to calculate the set value K of the division number.

[0026] The division number calculation unit 13 acquires the amount of data in the input buffer that is free (hereinafter also referred to as free buffer amount) from the wired receiving unit 11 as free buffer information of the input buffer (step S102). The division number calculation unit 13 also acquires from the wireless receiving unit 14 a packet loss rate and an RTT (Round-Trip Time) for each link of each frequency that the communication device 1 detected in wireless communication with the communication device 2 (step S103). The division number calculation unit 13 also acquires an input rate (amount of data received by the wired receiving unit 11 per unit time) from the input rate calculation unit 121 (step S104). The division number calculation unit 13 acquires an RSSI (Received Signal Strength Indicator) value for each link of each frequency that the communication device 1 detected in wireless communication with the communication device 2 (step S105). The division number calculation unit 13 calculates a setting value K for the number of divisions of the transmission data based on the acquired free buffer amount, packet loss rate, RTT, input rate, and RSSI value (step S106). A specific example of the calculation of the set value K is the same as the process described with reference to FIGS.

[0027] The division number calculation unit 13 outputs the division number setting value K to the encoding unit 124. The encoding unit 124 divides the transmission data by the division number setting value K (step S107). The encoding unit 124 generates a plurality of transmission unit packets, each of which includes one of the plurality of divided data pieces output by the division, or a plurality of transmission unit packets formed by the exclusive OR of a plurality of divided data pieces randomly selected from the plurality of divided data pieces (step S108). This is called encoding. The encoding unit 124 instructs the transmission rate control unit 125 to transmit the transmission unit packets in order.

[0028] The transmission rate control unit 125 acquires the input rate from the input rate calculation unit 121. The transmission rate control unit 125 acquires the allowable rate from the allowable rate calculation unit 122. The transmission rate control unit 125 selects the smaller value of the input rate and the allowable rate. The transmission rate control unit 125 determines the selected value as the transmission rate. The transmission rate control unit 125 instructs the transmitting unit 126 to transmit packets of a transmission unit in order at the determined transmission rate. The transmitting unit 126 selects a frequency from the first frequency 3a, the second frequency 3b, and the third frequency 3c according to the transmission rate. The transmitting unit 126 transmits the packets of a transmission unit in order at the determined transmission rate using an antenna of the selected frequency (step S109).

[0029] In the above process, after completing the transmission of all packets of divided data of the previously transmitted transmission data, the transmission rate control unit 125 divides the next transmission data into a number of divisions based on the new set value K obtained from the division number calculation unit 13.

[0030] In addition, the transmission rate calculation unit 123 may calculate the transmission rate using the input rate obtained from the wired receiving unit 11, the coding loss rate obtained from the coding unit 124, the packet loss rate obtained from the wireless receiving unit 14, the input rate obtained from the input rate calculation unit 121, and the allowable rate obtained from the allowable rate calculation unit 122.

[0031] The transmission of transmission data by communication device 1 described above is a technique for sequentially transmitting packets of divided data generated based on the set value K of the division number, even without a response signal from communication device 2. However, this method has the disadvantage of reducing the amount of communication data per unit time of other communication devices using the same wireless system. Therefore, communication device 1 may input information such as the congestion level for each frequency as network information and calculate the amount of data to be transmitted per unit time at the frequency to be used based on the congestion level. In this case, transmission rate control unit 125 may control the transmission rate using the amount of transmission data per unit time as an upper limit, thereby ensuring communication quality while maintaining a balance in the amount of communication data per unit time with other communication devices communicating using the same frequency band.

[0032] The wireless receiving unit 21 of the communication device 2 sequentially receives the packets transmitted from the communication device 1. The decoding unit 22 decodes the divided data using the received packets. The decoding unit 22 outputs the decoded divided data to the wired transmitting unit 23. The wired transmitting unit 23 reconstructs the transmission data by combining the divided data and sends it to the destination of the wired communication connection. The wireless transmitting unit 24 of the communication device 2 transmits a response signal to the communication device 1 in response to receiving each packet. The wireless receiving unit 14 of the communication device 1 receives the response signal and outputs the RTT calculated from the response signal to the encoding unit 124 and the division number calculation unit 13.

[0033] According to the above-described process, the communication device 1 divides and transmits the transmission data based on a set value K for the number of divisions of the transmission data, which is calculated based on transmission parameters between the communication device and the communication device that is the destination of the transmission data. This transmission parameter is a parameter that corresponds to the quality of the communication state between the communication device 1 and the communication device that is the destination of the transmission data. For example, the lower the input buffer consumption rate among the transmission parameters or the weaker the RSSI value, the larger the set value K for the number of divisions. Therefore, the worse the communication state, the larger the number of divisions of the transmission data. As a result, the communication device 1 increases the number of divisions to reduce the amount of data transmitted at one time as the communication state worsens, creating an environment in which packets can more easily reach the destination. On the other hand, the communication device 1 can decrease the number of divisions to increase the amount of data transmitted at one time as the communication state improves. According to this process, communication can be performed with a more appropriate amount of data per unit time depending on the state of wireless communication between the communication device 1 and the communication device 2.

[0034] In the above-described process, the division number calculation unit 13 may determine whether the communication state is poor based on the transmission parameters, such as the RSSI value or the amount of free buffer space, and may calculate the set value K of the division number according to the result of the determination of whether the communication state is poor based on the transmission parameters. For example, the division number calculation unit 13 inputs the transmission parameters into a determination formula for determining the communication state, compares the obtained numerical result with a threshold, and determines whether the communication state is poor based on the magnitude relationship between the two. Alternatively, the division number calculation unit 13 may determine whether the communication state is poor simply based on the magnitude relationship between the value of a transmission parameter, such as the RSSI value or the amount of free buffer space, and the threshold. If the division number calculation unit 13 determines that the communication state is poor, it sets the set value K of the division number to a large value. If the division number calculation unit 13 determines that the communication state is good, it sets the set value K of the division number to a small value. In this case, the division number calculation unit 13 may calculate the set value K according to the value of the transmission parameter or a value calculated using the determination formula for determining the communication state, or it may similarly calculate the set value K using the matrix data described above. Alternatively, the set value K may be calculated by inputting the value of the transmission parameter or a value calculated using a formula for determining the communication state into a formula for calculating a predetermined set value K.

[0035] FIG. 9 is a diagram showing the minimum configuration of a communication device. FIG. 10 is a diagram showing a processing flow of a communication device with a minimum configuration. The communication device 1 performs at least the functions of a division number calculation means 91, a division means 92, and a transmission means 93. The division number calculation means 91 calculates a set value for the division number of the transmission data based on the transmission parameters between the communication device 2 that is the destination of the transmission data (step S201). The division means 92 divides the transmission data based on the set value of the number of divisions (step S202). The transmitting means 93 generates multiple transmission units, each including one of the multiple divided data output by dividing the transmission data, or each consisting of the exclusive OR of multiple divided data randomly selected from the multiple divided data, and transmits them to the destination communication device (step S203).

[0036] FIG. 11 is a diagram illustrating the hardware configuration of the communication device. As shown in FIG. 11, the computer of communication device 1 or communication device 2 includes hardware such as a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, a HDD 104, a communication module 105, and a database 106. [Explanation of symbols]

[0037] 100 Wireless communication system 1,2 Communication equipment 3. Wireless communication section 11. Wired receiver 12, 24... Radio transmitter 13...Division number calculation unit (division number calculation means) 14, 21... Radio receiving unit 22 Decoding unit (division means) 23 Wired transmitter 121 Input rate calculation section 122 Allowable rate calculation section 123 Transmission rate calculation unit 124...encoding section 125 Transmission rate control section 126... Transmitting unit (transmitting means)

Claims

1. a division number calculation means for calculating a set value of the division number of the transmission data based on a transmission parameter between the transmission data and a communication device as a destination of the transmission data, the buffer consumption rate indicating an average accumulation amount per unit time in an input buffer of the transmission data received from a source, and an RSSI (Received Signal Strength Indicator) value indicating a communication state between the transmission data and the communication device as a destination; a division means for dividing the transmission data based on a set value of the division number; a transmitting means for generating a plurality of transmission units each including one of the plurality of divided data pieces output by dividing the transmission data, or each transmission unit being configured by the exclusive OR of a plurality of divided data pieces randomly selected from the plurality of divided data pieces, and transmitting the plurality of transmission units to the destination communication device; A communication device comprising:

2. The division number calculation means calculates a set value of the division number based on the transmission parameters indicating the communication state with the destination communication device. The communication device according to claim 1 .

3. The division number calculation means determines whether the communication state is poor based on the transmission parameters, and calculates a new set value for the division number according to the result of the determination whether the communication state is poor based on the transmission parameters. The communication device according to claim 2 .

4. The dividing means divides the next transmission data using the new set value of the number of divisions after completing transmission of all the division data of the transmission data that has been previously transmitted. The communication device according to any one of claims 1 to 3.

5. calculating a set value for the number of divisions of the transmission data based on a transmission parameter between the communication device that is a destination of the transmission data, the buffer consumption rate indicating an average accumulation amount per unit time in an input buffer of the transmission data received from the source, and an RSSI (Received Signal Strength Indicator) value indicating a communication state between the communication device and the destination of the transmission data; Dividing the transmission data based on the set value of the division number; A plurality of transmission units each including one of the plurality of divided data output by dividing the transmission data or each transmission unit configured by the exclusive OR of a plurality of divided data randomly selected from the plurality of divided data are generated, and transmitted to the destination communication device. Communication method.

6. The computer of the communication device, a division number calculation means for calculating a set value of the division number of the transmission data based on a transmission parameter between the transmission data and a communication device as a destination of the transmission data, the buffer consumption rate indicating an average accumulation amount per unit time in an input buffer of the transmission data received from a source, and an RSSI (Received Signal Strength Indicator) value indicating a communication state between the transmission data and the communication device as a destination; a division means for dividing the transmission data based on a set value of the number of divisions; a transmitting means for generating a plurality of transmission units each including one of the plurality of divided data pieces output by dividing the transmission data, or each transmission unit being configured by the exclusive OR of a plurality of divided data pieces randomly selected from the plurality of divided data pieces, and transmitting the plurality of transmission units to the destination communication device; A program that functions as a

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