JP6466285B2 - Reception device, transmission device, reception method, and transmission method - Google Patents

Description

  The present invention relates to a reception device, a transmission device, a reception method, and a transmission method that perform wireless communication in a wireless environment in which an interference signal exists.

  In recent years, with the diversification of wireless communication services, the number of mobile communication terminals such as smart phones and wireless LAN (Local Area Network) devices and other base station transmitters and receivers that perform wireless communication using various wireless communication methods has increased. doing. In a wireless communication system that uses signals that are radio waves of the same modulation system in the same frequency band, when the number of transmission devices and reception devices increases, each reception device receives a signal (hereinafter referred to as communication) from a transmission device that performs wireless communication. And a signal from another transmitting apparatus (hereinafter also referred to as an interference signal). For this reason, the probability that interference will occur between the communication signal and the interference signal in each receiving apparatus may increase, and the frequency utilization efficiency may deteriorate.

  Therefore, NOMA (Non-Orthogonal Multiple Access) uses SPC (Superposition Coding) and SIC (Successive Interference Canceller).

  For example, the receiving device sequentially demodulates from the signal indicating the maximum received power among the received signals received using the SIC, and when the demodulated signal is an interference signal, the interference signal is removed from the received signal. Techniques for demodulating communication signals have been proposed (see, for example, Non-Patent Document 1).

  FIG. 6 shows an example of wireless communication using SPC and SIC.

  As illustrated in FIG. 6, for example, the transmission devices Ta and Tb transmit signals 1 and 2 that are communication signals to the reception device Ra using the same modulation scheme as the transmission device Ta, respectively. The receiving device Ra receives the signals 1 and 2 and demodulates the signal having the highest received power. For example, when the power of the signal 1 is larger than the power of the signal 2, the receiving device Ra demodulates the signal 1 having the highest received power. Then, the receiving device Ra demodulates the signal 2 whose received power is smaller than the signal 1, so that the signal 1 demodulated by the SIC technique is used to generate a replica signal of the signal 1 in the radio section, and the replica signal is generated from the received signal. The signal 1 is removed by subtraction. The receiving device Ra demodulates the received signal from which the signal 1 is removed (that is, the signal 2), and ends the receiving process. When three or more signals are superimposed, the signal is demodulated by repeatedly executing the SIC technique.

Souvik Sen et al., “Successive interference cancellation: a back-of-the-envelope perspective”, 9th ACM SIGCOMM Workshop on Hot Topics in Networks, Article No. 17, 2010

  The receiving device Ra illustrated in FIG. 6 cannot demodulate the signal 2 that is smaller than the received power of the signal 1 when the signal 1 having the larger received power cannot be demodulated. In other words, the probability of successful transmission of a signal with low received power is lower than the probability of successful transmission of a signal with high received power, which may reduce throughput.

  In addition, as a wireless access method for performing wireless communication, there is a random access method in which slots divided by a time domain or a frequency domain are shared by a plurality of transmission apparatuses and reception apparatuses. In the random access method, an exponential backoff algorithm or the like is used to increase the time (hereinafter also referred to as window size) until the communication signal is retransmitted each time transmission of the communication signal fails. Maximize throughput by reducing traffic. However, if a communication signal with a smaller reception power cannot be transmitted due to a transmission failure with a communication signal having a large reception power, the random access scheme may not be able to optimize the traffic of the communication signal. In the random access method, there is a problem that the window size becomes too large and the throughput decreases.

  An object of the present invention is to provide a receiving device, a transmitting device, a receiving method, and a transmitting method capable of controlling the window size with higher accuracy than in the past in a wireless environment in which interference radio waves exist.

  The first invention measures a reception unit that receives a transmission signal transmitted from each of a plurality of transmission devices and a reception power of the reception signal received by the reception unit, and uses each successive interference cancellation method to determine each transmission signal. A demodulator for demodulating, a determination unit for determining whether or not a collision due to interference between the transmission signals has occurred based on the reception power measured by the demodulation unit and whether or not the demodulation of each transmission signal has been successful; A control unit that calculates a probability that demodulation by the demodulation unit fails due to a collision using the determination result by the determination unit, and notifies the calculated probability to each of the plurality of transmission apparatuses.

  In the first invention, the transmission signal transmitted from each of the plurality of transmission devices is transmitted at any one of at least two or more different transmission powers, and the control unit calculates the probability for each transmission power and calculates When the transmission signal is successfully demodulated together with the probability for each transmission power, the transmission apparatus is notified of information indicating success.

  According to a second aspect of the present invention, a receiving unit that receives a notification including a probability that a receiving device fails to demodulate a signal due to a collision caused by interference with a signal transmitted by another transmitting device from the receiving device; Using a control unit that updates a window size indicating a time interval for retransmitting the transmission signal to the receiving apparatus when transmission signal transmission fails, and when transmitting the transmission signal and transmission signal transmission fails And a transmission unit that retransmits the transmission signal with the calculated window size.

In the second invention, the transmission unit transmits a transmission signal at any one of at least two transmission powers different from each other, and the reception unit receives the probability for each transmission power and the reception device succeeds in demodulating the transmission signal. The control unit receives a notification including information indicating success from the receiving device, and the control unit counts the first number of times of receiving the information and the second number of times of transmitting and retransmitting the transmission signal, and counts the first count with the number and the second number and the probability of each transmission power, and updates the window rabbit size for each transmission power.

  According to a third aspect of the present invention, there is provided a reception step of receiving a transmission signal transmitted from each of a plurality of transmission devices, and a reception power of the reception signal received in the reception step, and each transmission signal is measured using a successive interference cancellation method. And a determination step for determining whether or not a collision due to interference between transmission signals has occurred based on the reception power measured in the demodulation step and whether or not the demodulation of each transmission signal was successful And a control step of calculating a probability that demodulation is failed in the demodulation step due to collision using the determination result in the determination step, and notifying each of the plurality of transmission devices of the calculated probability.

In the third invention, the transmission signal transmitted from each of the plurality of transmission devices is transmitted at any one of at least two transmission powers different from each other. In the control step , the probability is calculated for each transmission power, and the calculation is performed. When the transmission signal is successfully demodulated together with the probability for each transmission power, information indicating success is notified to the transmission apparatus.

  According to a fourth aspect of the present invention, there is provided a reception step of receiving a notification including a probability that the reception device fails to demodulate the signal due to a collision due to interference with a signal transmitted by another transmission device from the reception device; Control step for updating the window size indicating the time interval for retransmitting the transmission signal to the receiving device when transmission signal transmission fails, and when transmitting the transmission signal and transmission signal transmission fails And a transmission step of retransmitting the transmission signal with the calculated window size.

In the fourth invention, in the transmission step , the transmission signal is transmitted with any one of at least two transmission powers different from each other, and in the reception step , the probability for each transmission power and the reception apparatus successfully demodulate the transmission signal. A notification including information indicating success in the case is received from the receiving device, and in the control step , the first number of times of receiving the information and the second number of times of transmitting and retransmitting the transmission signal are counted and counted. by using the probability of each transmission power and the first number and the second number, and updates the window rabbit size for each transmission power.

  According to the present invention, the window size can be controlled with higher accuracy than the conventional one in a wireless environment in which interference radio waves exist.

1 is a diagram illustrating an embodiment of a wireless communication system. It is a figure which shows an example of the condition determination table shown in FIG. It is a figure which shows an example of the transmission / reception process in the radio | wireless communications system shown in FIG. FIG. 6 illustrates another embodiment of a wireless communication system. It is a figure which shows an example of the transmission / reception process in the radio | wireless communications system shown in FIG. It is a figure which shows an example of the radio | wireless communication using SPC and SIC.

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

  FIG. 1 shows an embodiment of a wireless communication system.

  The radio communication system SYS illustrated in FIG. 1 includes N transmission devices TX (TX1-TXN) and a reception device RX. Each of the transmission devices TX1-TXN transmits a signal sig (sig1-sigN) modulated with the same frequency and the same modulation scheme at any one of at least two transmission powers. On the other hand, the receiving device RX receives the signal sig transmitted by each transmitting device TX. Note that the transmission device TX may have the function of the reception device RX, and the reception device RX may have the function of the transmission device TX.

  The transmission device TX1 includes a reception unit 10, a control unit 20, and a transmission unit 30. Note that the transmission apparatuses TX2-TXN have the same elements as the transmission apparatus TX1.

  The receiving unit 10 sends a notification signal (not shown) including a probability for each transmission power that has failed to be demodulated due to a collision due to interference between the signals sig in the receiving device RX via the antenna included in the transmitting device TX1. Receive. In addition, when the receiving device RX succeeds in demodulating the signal sig1, the receiving unit 10 receives an ACK (Acknowledgment) signal (not shown) indicating successful demodulation. The receiving unit 10 outputs the received notification signal and ACK signal to the control unit 20.

  The control unit 20 is a processor or the like, and controls each element of the transmission device TX1 by executing a program stored in a storage device such as a memory included in the transmission device TX1. When the transmission of the signal sig1 fails (that is, when the ACK signal is not received from the receiving device RX), the control unit 20 receives the window size for each transmission power for retransmitting the signal sig1 to the receiving device RX. Calculate and update using each probability. The operation of the control unit 20 will be described with reference to FIGS.

  The transmission unit 30 transmits the signal sig1 with the transmission power instructed by the control unit 20 via the antenna included in the transmission device TX1. In addition, when the transmission of the signal sig1 fails, the transmission unit 30 retransmits the signal sig1 with the updated window size.

  Note that the transmitting apparatuses TX1-TXN may transmit with the same transmission power. Further, the transmission power at which the transmission unit 30 transmits the signal sig1 may be specified randomly by the control unit 20 executing a predetermined random number process, or may be preset to one of two or more transmission powers. Good. Alternatively, the transmission unit 30 may transmit the signal sig1 with the transmission power having the lowest probability of failure in demodulation.

  The reception device RX includes a reception unit 40, a demodulation unit 50, a determination unit 60, a control unit 70, a transmission unit 80, and a storage unit 90.

  The reception unit 40 receives the signal sig transmitted from each transmission device TX via an antenna included in the reception device RX.

  The demodulator 50 measures the received power of the received signal and demodulates each signal sig using the SIC.

  The determination unit 60 determines whether or not a collision due to interference between the signals sig has occurred based on the reception power measured by the demodulation unit 50 and whether or not the demodulation of each signal sig has succeeded. The operation of the determination unit 60 will be described with reference to FIG.

  The control unit 70 is a processor or the like, and controls each element of the reception device RX by executing a program stored in the storage unit 90 such as a memory. The control unit 70 calculates, for each transmission power of the signal sig, the probability that the demodulation unit 50 fails due to the collision between the signals sig using the result of the determination by the determination unit 60. The control unit 70 generates a notification signal including the calculated probability for each transmission power, and transmits the notification signal generated via the transmission unit 80 to each transmission device TX. In addition, when the signal sigk has been successfully demodulated, the control unit 70 generates an ACK signal indicating the success of the demodulation, and transmits the ACK signal to the transmission device TXk via the transmission unit 80 (k is a natural number from 1 to N). ). The control unit 70 may operate as the determination unit 60 by executing a program.

  The transmission unit 80 transmits the notification signal and the ACK signal generated by the control unit 70 via an antenna included in the reception device RX.

  The storage unit 90 is a flash memory or the like, and stores a situation determination table 95 indicating a determination result of the determination unit 60 together with a program executed by the control unit 70. The situation determination table 95 will be described with reference to FIG.

  FIG. 2 shows an example of the situation determination table 95 shown in FIG. The situation determination table 95 has areas for information indicating transmission power, information indicating situation determination, and information indicating probability.

  The transmission power area stores the value of transmission power PW (PW1, PW2,... PWM) when the transmission apparatus TX transmits the signal sig (M is a natural number).

  In the situation determination area, the situation of the signal sig at the transmission power PW is determined based on the reception power of the signal sig of the transmission power PW measured by the demodulator 50 and whether or not the signal sig of the transmission power PW is demodulated. The determination result by the determination unit 60 shown is stored for each determined time such as the time t1. The stored determination results include, for example, “success”, “collision”, and “empty”. “Success” indicates that the received power of the signal sig with the transmission power PW is equal to or higher than a predetermined value, and the signal sig with the transmission power PW is demodulated (that is, the signal sig is normally received and no collision occurs). Indicates. “Collision” indicates a situation where the reception power of the signal sig with the transmission power PW is equal to or greater than a predetermined value, but the demodulation of the signal sig with the transmission power PW has failed (that is, a collision has occurred). “Free” indicates that the received power of the signal sig with the transmission power PW is less than a predetermined value and the signal sig with the transmission power PW has not been received.

In the probability area, a value of Pa (Pa1, Pa2,... PaM) is stored with the probability of collision occurring in each transmission power PW in a predetermined period (that is, the rate of demodulation failure) as a probability. For example, the control unit 70 calculates the probability Paj using Expression (1) (j is a natural number from 1 to M).
Paj = (Number of collisions in a predetermined period) / (Number of all determinations in a predetermined period) (1)
The predetermined period is appropriately set according to the processing capability of the transmission device TX and the reception device RX, the quality of communication required for the radio communication system SYS, and the like. In addition, each time a new determination result is stored in the situation determination area, the probability Pa is calculated using the determination result from the newly stored determination result to a predetermined period before being stored in the probability area. May be.

  FIG. 3 shows an example of transmission / reception processing in the wireless communication system SYS shown in FIG. The process illustrated in FIG. 3 illustrates a case where wireless communication is performed between the transmission device TX1 and the reception device RX. Then, processing similar to the processing illustrated in FIG. 3 is performed between each of the transmission devices TX2-TXN and the reception device RX.

  In step S <b> 100, the control unit 20 determines whether a notification signal including the probability Pa for each transmission power PW is received from the reception device RX via the reception unit 10. When it determines with the control part 20 having received the notification signal, the process of the transmitter TX1 moves to step S110. On the other hand, when it determines with the control part 20 not receiving the control signal, the process of the transmitter TX1 moves to step S120.

  In step S110, the control unit 20 holds the probability Pa for each transmission power PW included in the notification signal received in step S110 in the storage device of the transmission device TX1.

  In step S120, for example, the transmission unit 30 transmits the signal sig1 including data to be transmitted to the reception device RX with the transmission power PWj.

  In step S130, the control unit 20 determines whether or not an ACK signal for the signal sig1 transmitted in step S120 is received from the receiving device RX. When the control unit 20 determines that the ACK signal has been received, the process of the transmission device TX1 ends. On the other hand, when it determines with the control part 20 not receiving the ACK signal, the process of the transmitter TX1 moves to step S140.

  In step S140, the control unit 20 updates the window size for each transmission power PW using the probability Pa for each transmission power PW held in step S110 and Equation (2).

Wj = W0j × Paj (2)
Wj indicates the window size at the updated transmission power PWj, and W0j indicates the window size at the transmission power PWj before the update.

  In step S150, the control unit 20 retransmits the signal sig1 transmitted in step S120 with the transmission power PWj at the back-off time interval determined using the window size Wj updated in step S140. In this case, the process of the transmission device TX1 proceeds to step S130.

  In step S200, the demodulator 50 measures the received power of the received signal received via the receiver 40, and sequentially uses the signal sig having the larger received signal among the signals sig included in the received signal using the SIC. Demodulate. Then, the demodulator 50 acquires data included in the signal sig.

  In step S210, the determination unit 60 sets the status of the signal sig at the transmission power PW to “success”, “collision”, or based on the reception power measured in step S200 and whether or not the demodulation of each signal sig is successful. Judgment is based on either “free”. The determination unit 60 stores the determination result of the situation for each transmission power PW in the situation determination area of the situation determination table 95 in association with the determined time.

  In step S220, the control unit 70 calculates the probability Pa for each transmission power PW using the determination result in the predetermined period including the situation determination determined in step S210 and Expression (1). The control unit 70 stores and updates the calculated probability Pa in the probability area of the situation determination table 95.

  In step S230, the control unit 70 generates a communication signal including the probability Pa for each transmission power PW calculated in step S220, and transmits the generated notification signal to each transmission device TX.

  In step S240, the control unit 70 determines whether or not there is a signal sig that has been successfully demodulated by the demodulation processing by the demodulation unit 50 in step S200. When determining that there is a signal sig that has been successfully demodulated, the control unit 70 generates an ACK signal for each transmission device TX that has transmitted the signal sig that has been successfully demodulated. In this case, the process of the reception device RX moves to step S250. On the other hand, when the control unit 20 determines that there is no signal sig that has been successfully demodulated, the processing of the receiving device RX ends.

  In step S250, the control unit 70 transmits the ACK signal generated in step S240 via the transmission unit 80 to each of the transmission devices TX that has transmitted the signal sig that has been successfully demodulated.

  Then, whenever the transmission device TX1 receives the notification signal from the reception device RX, the transmission device TX1 repeatedly executes the processing from step S100 to step S150. Further, every time the receiving device RX receives the signal sig from the transmitting device TX, the receiving device RX repeatedly executes the processing from step S200 to step S260. Note that the receiving device RX may execute the processing from step S210 to step S230 and the processing from step S240 to step S250 in parallel.

  As described above, in the embodiment illustrated in FIG. 1 to FIG. 3, the determination unit 60 of the reception device RX performs each transmission based on the reception power measured by the demodulation unit 50 and whether or not the demodulation of each signal sig is successful. The state of the signal sig at the power PW is determined. The control unit 70 calculates the probability Pa for each transmission power PW using the result of the situation determination, and transmits a communication signal including the calculated probability Pa to each transmission device TX. Thereby, the control unit 20 of the transmission apparatus TX updates the window size when transmission of the signal sig fails using the received probability Pa for each transmission power PW. That is, the wireless communication system SYS can control the window size with higher accuracy than the conventional one in a wireless environment in which interference radio waves exist, and can improve the throughput by, for example, 10%.

  FIG. 4 shows another embodiment of a wireless communication system. The same or similar elements as those described in FIG. 1 are denoted by the same or similar reference numerals, and detailed description thereof will be omitted.

  The radio communication system SYSa illustrated in FIG. 4 includes N transmission devices TXa (TXa1-TXaN) and a reception device RX. Each of the transmitters TXa1-TXaN transmits a signal sig (sig1-sigN) modulated with the same frequency and the same modulation scheme at any one of at least two transmission powers. Note that the transmission device TXa may have the function of the reception device RX, and the reception device RX may have the function of the transmission device TXa.

  The transmission device TXa1 includes a reception unit 10, a control unit 20a, and a transmission unit 30. Note that the transmission devices TXa2 to TXaN have the same elements as the transmission device TXa1.

  The control unit 20a is a processor or the like, and controls each element of the transmission device TXa1 by executing a program stored in a storage device such as a memory included in the transmission device TXa1.

  The control unit 20a includes, for example, the time when the ACK signal for the signal sig1 transmitted with the transmission power PW is received from the reception device RX, the time when the signal sig1 is transmitted and retransmitted with the transmission power PW, and the memory included in the transmission device TXa1. In the storage device. When the transmission of the signal sig1 has failed (that is, when the ACK signal has not been received from the receiving device RX), the control unit 20a determines from the time determined to have failed using the time held in the storage device to a predetermined time before The number of times of receiving the ACK signal is counted for each transmission power PW. In addition, the control unit 20a counts the number of times the signal sig1 is transmitted and retransmitted from the time when it is determined to have failed using the held time to the predetermined time before each transmission power PW. The predetermined time is preferably appropriately determined according to the processing capability of the transmission device TXa1 or the quality of communication required for the wireless communication system SYSa.

  Then, the control unit 20a subtracts the number of times of receiving the ACK signal (that is, the number of times of successful transmission) from the number of times of transmitting and retransmitting the signal sig1 (that is, the number of times of transmission), and calculates the number of times of failure to transmit the signal sig1. Calculation is performed for each transmission power PW. The control unit 20a divides the calculated number of times of transmission failure by the number of times of transmission of the signal sig1, and calculates the rate of failure of transmission of the signal sig1 to the receiving device RX as a failure probability for each transmission power PW. And the control part 20a updates the window size for every transmission power PW, for example using the calculated failure probability, the probability Pa for every transmission power PW acquired from the notification signal, and Formula (3).

Wj = W0j × (Paj / Pj) (3)
Pj indicates the failure probability at the transmission power PWj. And the control part 20a can set the window size which considered the radio | wireless environment where transmission apparatus TXa was set | placed by calculating failure probability Pj.

  FIG. 5 shows an example of transmission / reception processing in the radio communication system SYSa shown in FIG. Note that among the operations of the steps shown in FIG. 5, those showing the same or similar processing as the steps shown in FIG. 3 are given the same step numbers, and detailed descriptions thereof are omitted.

  The transmitting apparatus TXa1 executes the process of step S120a after executing the process of step S100 or step S110.

  In step S120a, the transmission unit 30 transmits the signal sig1 with the transmission power PWj, for example. Then, the control unit 20a holds the time when the signal sig1 of the transmission power PWj is transmitted in the storage device of the transmission device TXa1.

  In step S130a, the control unit 20a determines whether an ACK signal for the signal sig1 transmitted in step S120a is received from the receiving device RX. When determining that the ACK signal has been received, the control unit 20a holds the time at which the ACK signal was received in the storage device of the transmission device TXa1. In this case, the process of the transmission device TXa1 ends. On the other hand, when it determines with the control part 20a not receiving the ACK signal, the process of the transmitter TX1 moves to step S140a.

  In step S140a, the control unit 20a, the probability Pa for each transmission power PW held in step S110, the time when the ACK signal is received from the held receiver RX, the time when the held signal sig1 is transmitted and retransmitted, The window size for each transmission power PW is updated using Equation (3).

  For example, since the control unit 20a did not receive the ACK signal in step S130a (that is, the transmission of the signal sig1 failed), the control unit 20a does not receive the ACK signal until the predetermined time before it is determined to have failed using the held time. The number of times the ACK signal is received is counted for each transmission power PW. In addition, the control unit 20a counts the number of times the signal sig1 is transmitted and retransmitted from the time when it is determined to have failed using the held time until the predetermined time before, for each transmission power PW. Then, the control unit 20a subtracts the number of times of receiving the ACK signal from the number of times of transmitting and retransmitting the signal sig1, and calculates the number of times of transmission failure for each transmission power PW. The control unit 20a divides the calculated number of failed transmissions by the number of transmissions of the signal sig1, and calculates a failure probability Pj that the transmission of the signal sig1 to the receiving device RX has failed for each transmission power PW. Then, the control unit 20a updates the window size for each transmission power PW using the calculated failure probability Pj, the held probability Pa for each transmission power PW, and Equation (3).

  In step S150a, the control unit 20a retransmits the signal sig1 transmitted in step S120a with the transmission power PWj at the back-off time interval determined using the window size Wj updated in step S140a. Then, the control unit 20a holds the time when the signal sig1 of the transmission power PWj is transmitted in the storage device of the transmission device TXa1. In this case, the transmitting apparatus TXa1 proceeds to the process of step S130a.

  As described above, in the embodiment illustrated in FIGS. 4 and 5, the determination unit 60 of the reception device RX performs each transmission based on the reception power measured by the demodulation unit 50 and whether or not each signal sig has been successfully demodulated. The state of the signal sig at the power PW is determined. The control unit 70 calculates the probability Pa for each transmission power PW using the result of the situation determination, and transmits a communication signal including the calculated probability Pa to each transmission device TXa. Accordingly, the control unit 20 of the transmission device TXa uses the probability Pa for each received transmission power PW to update the window size even when transmission of the signal sig fails. That is, the wireless communication system SYSa can control the window size with higher accuracy than the conventional one in a wireless environment where interference radio waves exist, and can improve the throughput by 10%, for example.

  Further, the control unit 20a of the transmission device TXa can set the window size in consideration of the wireless environment where the transmission device TXa is placed by calculating the failure probability Pj. As a result, the wireless communication system SYSa can control the window size with higher accuracy and improve throughput in a wireless environment where interference radio waves exist.

  From the above detailed description, features and advantages of the embodiments will become apparent. This is intended to cover the features and advantages of the embodiments described above without departing from the spirit and scope of the claims. Also, any improvement and modification should be readily conceivable by those having ordinary knowledge in the art. Therefore, there is no intention to limit the scope of the inventive embodiments to those described above, and appropriate modifications and equivalents included in the scope disclosed in the embodiments can be used.

1, 2, sig1-sigN ... signal; 10, 40 ... reception unit; 20, 20a, 70 ... control unit; 30, 80 ... transmission unit; 50 ... demodulation unit; 90 ... storage unit; , RX: receiving device; SYS, SYSa ... wireless communication system; Ta, Tb, TX1-TXN, TXa1-TXaN ... transmitting device

Claims (8)

A receiving unit for receiving a transmission signal transmitted from each of a plurality of transmission devices;
A demodulator that measures received power of the received signal received by the receiver and demodulates each of the transmission signals using a successive interference cancellation method;
A determination unit for determining whether or not a collision due to interference between the transmission signals has occurred based on whether the reception power measured by the demodulation unit and demodulation of each transmission signal have been successful;
A control unit that calculates a probability that demodulation by the demodulation unit fails due to the collision using a result of determination by the determination unit, and notifies the calculated probability to each of the plurality of transmission devices. A receiving device. The receiving device according to claim 1,
A transmission signal transmitted from each of the plurality of transmission devices is transmitted at any one of at least two or more transmission powers different from each other,
The control unit calculates the probability for each transmission power, and notifies the transmission device of information indicating the success when the demodulation of the transmission signal is successful together with the calculated probability for each transmission power. A receiving device. A receiving unit that receives from the receiving device a notification including a probability that the receiving device fails to demodulate the signal due to a collision caused by interference with a signal transmitted by another transmitting device;
A control unit that updates a window size indicating a time interval for retransmitting the transmission signal to the reception device when transmission of the transmission signal fails using the received probability;
A transmission apparatus comprising: a transmission unit that transmits the transmission signal and retransmits the transmission signal with the window size calculated when transmission of the transmission signal fails. The transmission device according to claim 3, wherein
The transmission unit transmits the transmission signal at any one of at least two transmission powers different from each other,
The reception unit receives a notification including the probability for each transmission power and information indicating the success when the reception device has successfully demodulated the transmission signal from the reception device,
The control unit counts a first number of times the information is received and a second number of times the transmission signal is transmitted and retransmitted, and counts the first number, the second number, and the transmission power. by using the probability of each transmission apparatus and updates the window rabbit size for each of the transmission power. A reception step of receiving a transmission signal transmitted from each of the plurality of transmission devices;
A demodulation step of measuring the reception power of the reception signal received in the reception step, and demodulating each of the transmission signals using a successive interference cancellation method;
A determination step of determining whether or not a collision due to interference between the transmission signals has occurred based on whether the reception power measured in the demodulation step and demodulation of each transmission signal have been successful;
A control step of calculating a probability of demodulation failure in the demodulation step due to the collision using the determination result in the determination step, and notifying each of the plurality of transmission devices of the calculated probability. A characteristic reception method. The receiving method according to claim 5,
A transmission signal transmitted from each of the plurality of transmission devices is transmitted at any one of at least two or more transmission powers different from each other,
In the control step , the probability is calculated for each transmission power, and when the transmission signal is successfully demodulated together with the calculated probability for each transmission power, the transmission apparatus is notified of information indicating the success. A receiving method characterized by the above. A receiving step of receiving from the receiving device a notification including a probability that the receiving device fails to demodulate the signal due to a collision caused by interference with a signal transmitted by another transmitting device;
A control step of updating a window size indicating a time interval for retransmitting the transmission signal to the receiving device when transmission of the transmission signal fails using the received probability;
A transmission method comprising: transmitting the transmission signal, and retransmitting the transmission signal with the window size calculated when transmission of the transmission signal fails. The transmission method according to claim 7,
In the transmission step , the transmission signal is transmitted at any one of at least two transmission powers different from each other,
In the reception step , a notification including the probability for each transmission power and information indicating the success when the reception device has successfully demodulated the transmission signal is received from the reception device;
In the control step , the first number of times of receiving the information and the second number of times of transmitting and retransmitting the transmission signal are counted, and the counted first time and second times and the transmission are counted. transmission method characterized by using the probability for each power, and updates the window rabbit size for each of the transmission power.

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