Terminal

Abstract

This terminal comprises a management unit. When transmitting a high-priority frame including high-priority traffic for which low latency is required, the management unit causes a wireless signal processing unit to perform an operation for preferentially transmitting the high-priority frame. When transmitting a low-priority frame for which low latency is not required after the high-priority frame has been transmitted, the management unit causes the wireless signal processing unit to perform an operation for suppressing the transmission of the low-priority frame.

Description

Terminal

[0001] An embodiment relates to a terminal.

[0002] As a system for wirelessly connecting between an access point (AP) and a terminal (STA), a wireless LAN (Local Area Network) is known. By the wireless LAN, a terminal located within the communication area of the AP can access the network via the AP.

[0003] As a procedure for an AP or a terminal to acquire a channel access right, EDCA (enhanced distributed channel access) is known. However, in the conventional EDCA, in an environment where there are a large number of terminals, a terminal having higher-priority traffic has limited opportunities to acquire the channel access right.

[0004] In the next-generation wireless LAN standard, the IEEE 802.11be standard, various methods are being studied to enable a terminal having higher-priority traffic to preferentially secure the channel access right.

[0005] Dmitry Akhmetov et al., “Low latency channel access”, IEEE 802.11-24 / 0840r0, May, 2024

[0006] When a terminal having higher-priority traffic preferentially secures the channel access right, the opportunities for other terminals having lower-priority traffic to secure the channel access right will be limited. This will reduce the fairness of the transmission opportunity (TXOP) between terminals.

[0007] An embodiment provides a terminal that can improve the fairness of TXOP between terminals while a terminal having higher-priority traffic preferentially secures the channel access right.

[0008] One embodiment of the terminal includes a management unit. When the management unit sends high-priority frames, including high-priority traffic that requires low latency, it causes the wireless signal processing unit to perform an operation to prioritize the transmission of high-priority frames. When the management unit sends low-priority frames that do not require low latency after high-priority frames have been sent, it causes the wireless signal processing unit to perform an operation to suppress the transmission of low-priority frames.

[0009] According to this embodiment, a terminal is provided that can improve the fairness of TXOPs between terminals while ensuring that terminals with high-priority traffic have priority in securing channel access rights.

[0010] Figure 1 is a diagram showing an example of the configuration of a communication system according to an embodiment. Figure 2 is a block diagram showing an example of the hardware configuration of an AP. Figure 3 is a block diagram showing an example of the hardware configuration of a terminal. Figure 4 is a block diagram showing an example of the functional configuration of an AP according to an embodiment. Figure 5 is a block diagram showing an example of the functional configuration of a terminal according to an embodiment. Figure 6 is a block diagram showing an example of the functional configuration related to the transmission timing determination of a terminal. Figure 7 is a flowchart showing the traffic transmission operation of a terminal in a communication system. Figure 8 is a timing chart for explaining the operation for transmitting an example of a high-priority frame.

[0011] Embodiments will be described below with reference to the drawings. Figure 1 is a diagram showing an example of the configuration of a communication system according to the embodiment. As shown in Figure 1, the communication system 1 includes an access point (AP) 10, terminals (STAs) 20-1, 20-2, 20-3 and 20-4, and a network 30.

[0012] AP10 and terminals 20-1, 20-2, 20-3, and 20-4 have wireless communication capabilities based on, for example, the OSI (Open Systems Interconnection) reference model. In the OSI reference model, wireless communication capabilities are divided into seven layers (Layer 1: Physical Layer, Layer 2: Data Link Layer, Layer 3: Network Layer, Layer 4: Transport Layer, Layer 5: Session Layer, Layer 6: Presentation Layer, Layer 7: Application Layer). The data link layer includes an LLC (Logical Link Control) sublayer and a MAC (Media Access Control) sublayer. For example, the 2.4 GHz, 5 GHz, 6 GHz, 45 GHz, and 60 GHz bands may be used for wireless communication in communication system 1. Multiple channels are allocated to each frequency band. AP10 can communicate with each of terminals 20-1, 20-2, 20-3, and 20-4. In Figure 1, four terminals are shown, but the number of terminals is not limited to four.

[0013] Terminals 20-1, 20-2, 20-3, and 20-4 can exchange traffic with AP10. Terminals 20-1, 20-2, 20-3, and 20-4 are, for example, smartphones or PCs (personal computers), and are wireless terminals compliant with the IEEE 802.11 standard. In the following, when terminals 20-1, 20-2, 20-3, and 20-4 are not specifically distinguished, they may each be referred to as terminal 20.

[0014] Next, the hardware configuration of the AP and terminal in the communication system according to the embodiment will be described.

[0015] Figure 2 is a block diagram showing an example of the hardware configuration of an AP. As shown in Figure 2, the AP 10 includes, for example, a CPU (central processing unit) 11, ROM (read-only memory) 12, RAM (random access memory) 13, a wireless communication module 14, and a wired communication module 15.

[0016] The CPU 11 is a processing circuit that controls the overall operation of the AP 10. The ROM 12 is, for example, a non-volatile semiconductor memory. The ROM 12 stores programs and data for controlling the AP 10. The RAM 13 is, for example, a volatile semiconductor memory. The RAM 13 is used as a workspace for the CPU 11. The wireless communication module 14 is a circuit used for sending and receiving data via wireless signals. The wireless communication module 14 is connected to an antenna. The wired communication module 15 is a circuit used for sending and receiving data via wired signals. The wired communication module 15 is connected to the network 30.

[0017] Although the wired communication module 15 is described as a means of connecting AP 10 and network 30, alternatively, a wireless communication module different from the wireless communication module 14 may be used to connect AP 10 and network 30, or the wireless communication module 15 may communicate with network 30 during times when it is not communicating with terminal 20.

[0018] Figure 3 is a block diagram showing an example of the hardware configuration of a terminal. As shown in Figure 3, the terminal 20 includes, for example, a CPU 21, ROM 22, RAM 23, a wireless communication module 24, a display 25, and storage 26.

[0019] The CPU 21 is a processing circuit that controls the overall operation of the terminal 20. The ROM 22 is, for example, a non-volatile semiconductor memory. The ROM 22 stores programs and data for controlling the terminal 20. The RAM 23 is, for example, a volatile semiconductor memory. The RAM 23 is used as a workspace for the CPU 21. The wireless communication module 24 is a circuit used for sending and receiving data via wireless signals. The wireless communication module 24 is connected to an antenna. The display 25 is, for example, an LCD (liquid crystal display) or an EL (electro-luminescence) display. The display 25 displays a GUI (graphical user interface) etc. corresponding to the application software. The storage 26 is a non-volatile storage device. The storage 26 stores the system software etc. of the terminal 20.

[0020] Next, the functional configuration of the AP and terminal in the communication system according to the embodiment will be described.

[0021] Figure 4 is a block diagram showing an example of the functional configuration of an AP according to an embodiment. AP10 functions as a computer comprising a data processing unit 110, a frame processing unit 120, a management unit 130, and a wireless signal processing unit 140. The data processing unit 110 is a functional block that executes processing corresponding to the LLC sublayer of the second layer and layers 3 through 7. The frame processing unit 120 and the management unit 130 are functional blocks that execute processing corresponding to the MAC sublayer of the second layer. The wireless signal processing unit 140 is a functional block that executes processing corresponding to the first layer.

[0022] The data processing unit 110 outputs data received from the network 30 via the LLC layer to the frame processing unit 120. The data processing unit 110 also outputs data received from the frame processing unit 120 to the network 30 via the LLC layer.

[0023] When data is input from the data processing unit 110 or the management unit 130, the frame processing unit 120 adds a MAC header to the input data to generate a MAC frame. The frame processing unit 120 then outputs the MAC frame to the wireless signal processing unit 140. Furthermore, when a MAC frame is input from the wireless signal processing unit 140, the frame processing unit 120 extracts data from the MAC frame and outputs the extracted data according to the type of MAC frame to the data processing unit 110 or the management unit 130. Specifically, if the MAC frame is a data frame, the frame processing unit 120 inputs the data to the data processing unit 110. If the MAC frame is a management frame or a control frame, the frame processing unit 120 inputs the data to the management unit 130.

[0024] The management unit 130 controls the logical wireless connection between the AP 10 and the terminal 20. For example, the management unit 130 executes wireless connection processing in response to an association request from the terminal 20.

[0025] The wireless signal processing unit 140 generates a wireless frame by adding a preamble and the like to the MAC frame input from the frame processing unit 120. The wireless signal processing unit 140 converts the generated wireless frame into a wireless signal. The wireless signal processing unit 140 then transmits the converted wireless signal via the antenna. The conversion process from wireless frame to wireless signal includes, for example, error correction coding, interleaving, subcarrier modulation, inverse fast Fourier transform, OFDM modulation, and frequency conversion. The wireless signal processing unit 140 also converts the wireless signal received via the antenna into a wireless frame. The conversion process from wireless signal to wireless frame includes, for example, frequency conversion, OFDM demodulation, fast Fourier transform, subcarrier demodulation, deinterleaving, and error correction decoding. The wireless signal processing unit 140 extracts the MAC frame from the converted wireless frame. The wireless signal processing unit 140 then outputs the extracted MAC frame to the frame processing unit 120.

[0026] Figure 5 is a block diagram showing an example of the functional configuration of a terminal according to the embodiment. The terminal 20 functions as a computer comprising a data processing unit 210, a frame processing unit 220, a management unit 230, a wireless signal processing unit 240, and an application execution unit 250. The data processing unit 210 is a functional block that executes processing corresponding to the LLC sublayer of the second layer and layers 3 through 7. The frame processing unit 220 and the management unit 230 are functional blocks that execute processing corresponding to the MAC sublayer of the second layer. The wireless signal processing unit 240 is a functional block that executes processing corresponding to the first layer. The application execution unit 250 is a functional block that executes processing corresponding to layer 7.

[0027] The data processing unit 210 outputs data received from the application execution unit 250 via the LLC layer to the frame processing unit 220. The data processing unit 210 also outputs data received from the frame processing unit 220 to the application execution unit 250 via the LLC layer.

[0028] When data is input from the data processing unit 210 or the management unit 230, the frame processing unit 220 adds a MAC header to the input data to generate a MAC frame. The frame processing unit 220 then outputs the MAC frame to the wireless signal processing unit 240. Furthermore, when a MAC frame is input from the wireless signal processing unit 240, the frame processing unit 220 extracts data from the MAC frame and outputs the extracted data according to the type of MAC frame to the data processing unit 210 or the management unit 230. Specifically, if the MAC frame is a data frame, the frame processing unit 220 inputs the data to the data processing unit 210. If the MAC frame is a management frame or a control frame, the frame processing unit 220 inputs the data to the management unit 230.

[0029] The management unit 230 controls the logical wireless connection between the terminal 20 and the AP 10. For example, the management unit 230 generates an association request based on a beacon frame from the AP 10. The management unit 230 also includes a transmission timing determination unit 231, a counter 232, a timer 233, and an other frame detection unit 234.

[0030] The transmission timing determination unit 231 determines the transmission timing of the wireless signal. When sending a high-priority frame, the transmission timing determination unit 231 determines the transmission timing so that the wireless signal is transmitted preferentially. On the other hand, when sending a low-priority frame, the transmission timing determination unit 231 determines the transmission timing according to the count of the counter 232, i.e., the number of times a high-priority frame has been sent. Specifically, when the count of the counter 232 is above a threshold, the transmission timing determination unit 231 determines the transmission timing so that the transmission of the wireless signal is suppressed. A high-priority frame is a data frame that contains high-priority traffic for which low latency is required. High-priority traffic may be, for example, traffic that has even higher transmission priority than traffic associated with access categories AC_VO, AC_VI, AC_BE, or AC_BK, which will be described later. On the other hand, a low-priority frame is a data frame that contains low-priority traffic for which low latency is not required. Low-priority frames may be, for example, traffic associated with access categories AC_VO, AC_VI, AC_BE, or AC_BK.

[0031] Counter 232 is a counter for counting the frequency of transmission of high-priority frames. Counter 232 is incremented by 1 each time a high-priority frame is transmitted or each time a high-priority frame is successfully transmitted. On the other hand, counter 232 is decremented by 1 when a certain amount of time has elapsed or when transmission of a data frame by another terminal 20 is detected.

[0032] Timer 233 is a timer for measuring a certain period of time that is the condition for the countdown in counter 232. Timer 233 notifies counter 232 each time a certain period of time has elapsed. Other frame detection unit 234 detects data frames transmitted by other terminals 20 that are the condition for the countdown in counter 232. For example, when the source address included in the header of a data frame input via the wireless signal processing unit 240 is the address of another terminal 20, other frame detection unit 234 notifies counter 232 that a data frame has been transmitted by another terminal 20.

[0033] The wireless signal processing unit 240 generates a wireless frame by adding a preamble and the like to the MAC frame input from the frame processing unit 220. The wireless signal processing unit 240 converts the generated wireless frame into a wireless signal. The wireless signal processing unit 240 then transmits the converted wireless signal via the antenna. The conversion process from wireless frame to wireless signal includes, for example, error correction coding, interleaving, subcarrier modulation, inverse fast Fourier transform, OFDM modulation, and frequency conversion. The wireless signal processing unit 240 also converts the wireless signal received via the antenna into a wireless frame. The conversion process from wireless signal to wireless frame includes, for example, frequency conversion, OFDM demodulation, fast Fourier transform, subcarrier demodulation, deinterleaving, and error correction decoding. The wireless signal processing unit 240 extracts the MAC frame from the converted wireless frame. The wireless signal processing unit 240 then outputs the extracted MAC frame to the frame processing unit 220.

[0034] The application execution unit 250 executes an application based on data input from the data processing unit 210. The application execution unit 250 also inputs data to the data processing unit 210. For example, the application execution unit 250 can display application information on the display 25. Furthermore, the application execution unit 250 can operate based on operations on the input interface.

[0035] Figure 6 is a block diagram showing an example of the functional configuration related to the transmission timing determination of terminal 20. The functional configuration shown in Figure 6 is provided in the wireless signal processing unit 240. Although Figure 6 is a block diagram showing an example of the functional configuration related to the transmission timing determination of terminal 20, a similar configuration is also provided in the wireless signal processing unit 140 of AP 10.

[0036] The wireless signal processing unit 240 includes a data categorization unit 241, a plurality of transmission queues 242A, 242B, 242C, and 242D, a plurality of carrier sense units 243A, 243B, 243C, and 243D, and an internal collision management unit 244.

[0037] The data categorization unit 241 classifies the data frame into multiple access categories based on the TID (traffic identifier) ​​contained in the MAC header. The TID is an identifier that indicates traffic and can be associated with an access category. Traffic access categories include, for example, "AC_VO (voice)", "AC_VI (video)", "AC_BE (best effort)", and "AC_BK (background)". The transmission priority of traffic associated with an access category is in the order of AC_VO, AC_VI, AC_BE, and AC_BK. The data categorization unit 241 inputs the data frame into the corresponding transmission queue among the multiple transmission queues 242A, 242B, 242C, and 242D. In the example shown in Figure 6, the data categorization unit 241 inputs data frames corresponding to access categories AC_VO, AC_VI, AC_BE, and AC_BK into transmission queues 242A, 242B, 242C, and 242D, respectively. Here, the data categorization unit 241 inputs high-priority frames into, for example, transmission queue 242A or an available transmission queue. If a dedicated transmission queue for high-priority frames is provided, the data categorization unit 241 may input high-priority frames into the dedicated transmission queue for high-priority frames.

[0038] Each of the multiple transmit queues 242A, 242B, 242C, and 242D buffers the incoming data frames. In the example in Figure 6, each of the multiple transmit queues 242A, 242B, 242C, and 242D buffers the data frames corresponding to access categories AC_VO, AC_VI, AC_BE, and AC_BK, respectively.

[0039] Each of the multiple carrier sense units 243A, 243B, 243C, and 243D corresponds to each of the multiple transmission queues 242A, 242B, 24C, and 242D. Each of the multiple carrier sense units 243A, 243B, 243C, and 243D performs carrier sense processing based on CSMA / CA (carrier sense multiple access with collision avoidance) according to pre-configured access parameters for EDCA. If the channel is determined to be idle, each of the multiple carrier sense units 243A, 243B, 243C, and 243D acquires channel access rights and terminates carrier sense processing. If the channel is determined to be busy, each of the multiple carrier sense units 243A, 243B, 243C, and 243D cancels the acquisition of channel access rights and terminates carrier sense processing.

[0040] Access parameters used include, for example, CW (contention window) min, CW max, AIFS (arbitration inter frame space), and TXOP (transmission opportunity) Limit. CW min and CW max represent the minimum and maximum values ​​of the contention window, respectively. The contention window is a parameter that indicates the time range used to determine random backoff for collision avoidance. AIFS is a fixed transmission waiting time set for each access category. TXOP Limit indicates the upper limit of TXOP, which is the channel occupancy period. In other words, the shorter the CW min and CW max, and the AIFS, the easier it is to acquire channel access rights. Also, the larger the TXOP Limit, the more data can be transmitted when channel access rights are obtained in a single instance.

[0041] The internal collision management unit 244 prevents transmission collisions when two or more carrier sense units simultaneously acquire channel access rights. Specifically, for example, if multiple data frames are input simultaneously, the internal collision management unit 244 prioritizes outputting data frames from the access category with higher priority. The data frames output from the internal collision management unit 244 are converted into wireless signals as described above.

[0042] Next, the operation of the communication system according to the embodiment will be described. Figure 7 is a flowchart showing the traffic transmission operation of terminal 20 in the communication system 1. In other words, Figure 7 shows the uplink operation of sending traffic from terminal 20 to AP 10.

[0043] In step S1, terminal 20 determines whether to send a data frame to AP 10, that is, whether traffic that should be sent to AP 10 has occurred. If it is determined in step S1 to send a data frame to AP 10, the process proceeds to step S2. If it is determined in step S1 not to send a data frame to AP 10, the process proceeds to step S8.

[0044] In step S2, the terminal 20 determines whether the data frame to be sent to the AP 10 is a high-priority frame. If it is determined in step S2 that the data frame to be sent to the AP 10 is a high-priority frame, the process proceeds to step S3. If it is determined in step S2 that the data frame to be sent to the AP 10 is not a high-priority frame, that is, a low-priority frame, the process proceeds to step S5.

[0045] In step S3, the terminal 20 performs an operation for sending a high-priority frame. The operation for sending a high-priority frame can be any operation known as an operation for sending a high-priority frame. For example, the operation for sending a high-priority frame can be preemption, r-TWT (restricted target wake time), TXOP sharing, etc. Or, the operation for sending a high-priority frame may be the sending of a high-priority frame using multi-link or multi-AP. Hereinafter, another example of an operation for sending a high-priority frame will be described.

[0046] FIG. 8 is a timing chart for explaining an operation for sending an example of a high-priority frame. STA_1, STA_2, STA_3, and STA_4 in FIG. 8 respectively correspond to terminals 20-1, 20-2, 20-3, and 20-4. For the sake of explanation, in the example of FIG. 8, it is assumed that traffic occurs simultaneously in STA_1, STA_2, STA_3, and STA_4. The traffic that occurs in STA_1 and STA_2 is low-priority traffic. On the other hand, the traffic that occurs in STA_3 and STA_4 is high-priority traffic. That is, in FIG. 8, STA_3 and STA_4 perform an operation for sending a high-priority frame.

[0047] When low-priority traffic occurs in STA_1 and STA_2, they attempt to acquire channel access rights according to the normal EDCA procedure. In the normal EDCA procedure, first, it is confirmed whether the channel is busy by performing a channel sense for each AIFS associated with the traffic. Then, when there is no transmission of a wireless signal by other terminals at the time when the AIFS has elapsed and the channel is idle, further, it is confirmed whether there is a transmission of a wireless signal by other terminals during the random backoff set within the contention window. Then, when there is no transmission of a wireless signal by other terminals after the random backoff ends and the channel is idle, the terminal acquires the channel access right. The terminal that has acquired the channel access right can transmit a wireless signal during the TXOP period. In FIG. 8, an example is shown in which STA_1 is performing a channel sense during AIFS_1 and STA_2 is performing a channel sense during AIFS_2.

[0048] On the other hand, when high-priority traffic occurs in STA_3 and STA_4, they attempt to acquire channel access rights according to a procedure different from the conventional EDCA procedure. Specifically, instead of starting a carrier sense to acquire the channel access right, STA_3 and STA_4 transmit a predetermined wireless signal DS (defer signal), for example, addressed to AP10, when a period such as DIFS (distributer inter frame space), which is shorter than the shortest AIFS, that is, shorter than the AIFS of access category AC_VO, has elapsed. The transmission of the wireless signal DS is not limited to after the elapse of DIFS as long as it is shorter than the AIFS. Also, the wireless signal DS may be a signal including any frame.

[0049] STA_1 and STA_2 terminate their channel access acquisition operation by detecting that the channel is busy through carrier sensing. Meanwhile, STA_3 and STA_4 perform carrier sensing during random backoff after transmitting the DS signal to check whether the channel is busy or not. In the example in Figure 8, STA_3's random backoff ends before STA_4's random backoff. Therefore, STA_3 acquires channel access. Having acquired channel access, STA_3 can transmit radio signals including high-priority frames. Meanwhile, STA_4 terminates its channel access acquisition operation by detecting that the channel is busy due to the transmission of radio signals by STA_3 during random backoff.

[0050] As shown in Figure 8, in the operation of sending high-priority frames, the terminal sending the high-priority frame transmits a DS signal during the carrier sense of the terminal sending the low-priority frame, unlike the normal EDCA procedure. As a result, the terminal sending the low-priority frame detects that the channel is busy as a result of the carrier sense and terminates the acquisition of channel access rights. Therefore, the terminal sending the high-priority frame has an easier time acquiring channel access rights than the terminal sending the low-priority frame.

[0051] Furthermore, in the high-priority frame transmission operation shown in Figure 8, STA_1 and STA_2, which transmit low-priority frames, detect channel busy due to the transmission of a DS signal by carrier sensing in the normal EDCA procedure and terminate the operation to acquire channel access rights. In other words, STA_1 and STA_2 can be any terminal capable of performing the normal EDCA procedure. Therefore, STA_1 and STA_2 may be legacy terminals that do not support the transmission of various high-priority frames.

[0052] Here, although not shown in Figure 8, STA_1, STA_2, STA_3, and STA_4 may perform the same channel access acquisition operation as in Figure 8 again after the completion of the TXOP given to STA_3. On the other hand, if only certain terminals continue to acquire channel access rights, it will lead to a decrease in fairness among terminals. Therefore, in this embodiment, terminals that send high-priority frames suppress the sending of low-priority frames in order to prioritize the sending of frames by other terminals. This improves fairness among terminals.

[0053] The explanation of Figure 7 returns below. In step S4, after sending a high-priority frame in step S3, terminal 20 increments counter 232 by 1. Then, the process returns to step S1. Note that terminal 20 may increment counter 232 not when the operation to send a high-priority frame is performed, but when the transmission of the high-priority frame is actually successful. In this case, if the transmission of the high-priority frame in step S3 fails, counter 232 will not be incremented, and the process returns to step S1.

[0054] In step S5, terminal 20 determines whether the count of counter 232 is equal to or greater than a threshold. The threshold is not limited to this, but for example it is 1. If in step S5 it is determined that the count of counter 232 is not equal to or greater than the threshold, the process proceeds to step S6. If in step S5 it is determined that the count of counter 232 is equal to or greater than the threshold, the process proceeds to step S7.

[0055] In step S6, terminal 20 performs an operation to send a low-priority frame. The operation to send a low-priority frame may be an operation according to the EDCA described above. After performing the operation to send a low-priority frame, the process returns to step S1.

[0056] In step S7, terminal 20 suppresses the operation to send low-priority frames. For example, terminal 20 does not perform the EDCA procedure for sending low-priority frames by the radio signal processing unit 240. In this case, the process returns to step S1. Alternatively, terminal 20 changes the EDCA access parameters for sending low-priority frames so that sending low-priority frames is suppressed. For example, terminal 20 changes CWmin and CWmax to be increased or TXOPLimit to be decreased. When changing CWmin and CWmax to be increased, terminal 20 may increase CWmin and CWmax as the count of counter 232 increases. That is, the count of counter 232 may be considered as the number of transmission failures, and CWmin and CWmax may be increased in the same way as when a retransmission occurs in the normal EDCA procedure. Such changes to access parameters can be made by the transmission timing determination unit 231 of the management unit 230 instructing the wireless signal processing unit 240. When such changes to access parameters are made, terminal 20 performs the operation to send the low-priority frame described above using the changed access parameters. After that, the process returns to step S1. In this way, if the counter of counter 232 is above the threshold, that is, if the number of operations to send high-priority frames is above the threshold or the number of successful high-priority frame transmissions is above the threshold, the transmission of low-priority frames is suppressed compared to other terminals. This makes it easier for other terminals to acquire channel access rights and can improve the fairness of TXOPs between terminals.

[0057] In step S8, terminal 20 determines whether the transmission of a data frame by another terminal 20 has been detected by the other frame detection unit 234 or whether a certain period of time has been measured by the timer 233. The certain period of time is not limited to this, but for example it is 100 milliseconds. In step S8, if terminal 20 determines that the transmission of a data frame by another terminal 20 has been detected by the other frame detection unit 234 or that a certain period of time has been measured by the timer 233, the process proceeds to step S9. In step S8, if it is determined that the transmission of a data frame by another terminal 20 has not been detected by the other frame detection unit 234 and that a certain period of time has not been measured by the timer 233, the process returns to step S1.

[0058] In step S9, terminal 20 counts down counter 232 by 1. Then, the process returns to step S1. As a result, if the count of counter 232 falls below the threshold, terminal 20 may send a low-priority frame in the same way as other terminals 20.

[0059] As described above, according to the embodiment, a terminal that sends high-priority frames will send high-priority frames without restriction. On the other hand, a terminal that has sent a high-priority frame will suppress the subsequent sending of low-priority frames. In this way, a terminal determines the timing of sending a data frame based on whether the generated data frame is a high-priority frame and the number of times high-priority frames have been sent. This makes it possible to improve the fairness of TXOPs between terminals while preferentially securing channel access rights for terminals with high-priority traffic.

[0060] (Modifications) Modifications of the embodiment are described below. In the embodiment, each terminal 20 counts the number of times it has sent its own high-priority frame and suppresses the subsequent sending of low-priority frames. Alternatively, AP 10 may count the number of times each terminal 20 has sent high-priority frames and suppress the sending of low-priority frames by terminals 20 that have sent a large number of high-priority frames.

[0061] Furthermore, the processing performed in terminal 20, as shown in Figure 7, can also be stored as a program that can be executed by a computer processor. In addition, it can be stored and distributed on external storage media such as magnetic disks, optical disks, and semiconductor memory. Each processor in terminal 20 can then read the program stored on the external storage media, and its operation is controlled by the read program, enabling it to perform various processes.

[0062] It should be noted that the present invention is not limited to the embodiments described above, and can be modified in various ways during implementation without departing from its essence. Furthermore, each embodiment may be combined as appropriate, and in that case, the combined effects can be obtained. Moreover, the above embodiments include various inventions, and various inventions can be extracted by selecting combinations from the multiple constituent elements disclosed. For example, if the problem can be solved and effects obtained even if some constituent elements are deleted from all the constituent elements shown in the embodiment, then the configuration with these deleted constituent elements can be extracted as an invention.

[0063] 1...Communication system 10...Access point (AP) 11...CPU 12...ROM 13...RAM 14...Wireless communication module 15...Wired communication module 20, 20-1, 20-2, 20-3, 20-4...Terminals 21...CPU 22...ROM 23...RAM 24...Wireless communication module 25...Display 26...Storage 30...Network 110...Data processing unit 120...Frame processing unit 130...Management unit 140...Wireless signal processing unit 210...Data processing unit 220...Frame processing unit 230...Management unit 231...Transmission timing determination unit 232...Counter 233...Timer 234...Other frame detection unit 240...Wireless signal processing unit 250...Application execution unit

Claims

1. A terminal equipped with a management unit that, when transmitting high-priority frames including high-priority traffic requiring low latency, causes the wireless signal processing unit to perform an operation to prioritize the transmission of said high-priority frames, and when transmitting low-priority frames that do not require low latency after the said high-priority frames have been transmitted, causes the wireless signal processing unit to perform an operation to suppress the transmission of said low-priority frames.

2. The terminal according to claim 1, wherein the management unit does not perform the operation for the wireless signal processing unit to send the low-priority frame as an operation to suppress the transmission of the low-priority frame.

3. The terminal according to claim 1, wherein the management unit, as an operation to suppress the transmission of the low-priority frame, changes the access parameters used in the operation for transmission of the low-priority frame by the wireless signal processing unit so as to suppress the transmission of the low-priority frame.

4. The terminal according to claim 1, wherein the management unit increments a counter each time a high-priority frame is transmitted or successfully transmitted, decrements the counter at regular intervals or each time a data frame is transmitted from another terminal, and when transmitting a low-priority frame, causes the wireless signal processing unit to suppress the transmission of the low-priority frame if the count of the counter is above a threshold.

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