Wireless device and wireless communication method

Abstract

A wireless device according to an aspect of the present invention is provided with a communication unit, a first calculation unit, a second calculation unit, and a transmission control unit. The communication unit performs wireless communication with another wireless device by using a plurality of links established between the wireless device and the other wireless device. The first calculation unit calculates a frame exchange period including a time period required for frame transmission to the other wireless device. The second calculation unit calculates, for each of the plurality of links, a communicable period indicating a time period until a service period in which a transmission opportunity is given starts. The transmission control unit performs frame transmission by using a link having a frame exchange period shorter than a communicable period when there is the link having a frame exchange period shorter than a communicable period, and postpones the frame transmission when there is no link having a frame exchange period shorter than a communicable period.

Description

[Technical Field]

[0001] The present invention relates to wireless communications. [Background technology]

[0002] Wireless LANs (Local Area Networks) are known as communication systems that wirelessly connect access points and terminal devices. In wireless LANs, the access points and terminal devices each perform carrier sensing based on, for example, CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance), and wirelessly transmit data frames when they acquire the right to transmit.

[0003] IEEE802.11be, the successor to IEEE802.11ax, is currently being developed, and r-TWT (restricted Target Wake Time) operation is being considered. r-TWT operation specifies a mechanism to prioritize transmission opportunities for traffic with delay requirements. Traffic with delay requirements, also known as low-delay traffic or delay-sensitive traffic, is traffic that requires low latency and small jitter, such as traffic generated by real-time applications such as network games.

[0004] In r-TWT operation, a terminal device exchanges frames with an access point during a service period (SP) set for the terminal device by the access point, and other terminal devices around the access point are restricted from communicating on the link for which the service period is set during part of the service period. The terminal device can use the service period to wirelessly transmit data frames containing low-latency traffic to the access point. Thus, the service period is a period during which a transmission opportunity is provided to a terminal device designated by the access point, allowing the terminal device designated by the access point to preferentially transmit and receive data frames containing low-latency traffic. This service period is also called an r-TWT service period.

[0005] A terminal device that acquires a transmission right before the start of the r-TWT service period checks whether it can complete the transmission of the data frame it is about to transmit by the start of the r-TWT service period. If it cannot complete the transmission, the terminal device postpones the transmission of the data frame and starts transmitting the data frame after the end of the r-TWT service period.

[0006] Multiple terminal devices may postpone transmission for the r-TWT service period, and in this case, these terminal devices may start transmitting simultaneously after the r-TWT service period ends, which may cause collisions and make normal data transmission and reception impossible.

[0007] Backoff control can be used to avoid collisions caused by simultaneous transmission of data frames after the end of the r-TWT service period. For example, multiple terminal devices that postponed transmission may perform carrier sensing again after the end of the r-TWT service period, and transmit once they have acquired the transmission right again. In this case, even though they had once acquired the transmission right before the r-TWT service period, backoff control must be performed again to acquire the transmission right, resulting in reduced frequency utilization efficiency. [Prior art documents] [Non-patent literature]

[0008] [Non-Patent Document 1] IEEE P802.11beTM / D1.5, “35.9 Restricted TWT (r-TWT)”, March 18, 2022. Summary of the Invention [Problem to be solved by the invention]

[0009] The occurrence of collisions and the decrease in frequency utilization efficiency as described above result in a decrease in throughput and delay characteristics.

[0010] An object of the present invention is to provide a wireless communication technology that improves throughput and delay characteristics. [Means for solving the problem]

[0011] A wireless device according to one aspect of the present invention includes a communication unit, a first calculation unit, a second calculation unit, and a transmission control unit. The communication unit wirelessly communicates with another wireless device using multiple links established between the wireless device and the other wireless device. The first calculation unit calculates a frame exchange period including a time period required to transmit a frame to the other wireless device. The second calculation unit calculates, for each of the multiple links, a communication available period indicating a time period until a service period in which a transmission opportunity is provided begins. The transmission control unit, if there is a link whose frame exchange period is shorter than the communication available period, transmits the frame over the link whose frame exchange period is shorter than the communication available period, and if there is no link whose frame exchange period is shorter than the communication available period, postpones the frame transmission. [Effects of the Invention]

[0012] According to the present invention, a wireless communication technique that improves throughput and delay characteristics is provided. [Brief explanation of the drawings]

[0013] [Figure 1]FIG. 1 is a block diagram showing a communication system according to an embodiment. [Figure 2] FIG. 2 is a diagram showing link management information according to the embodiment. [Figure 3] FIG. 3 is a block diagram showing a hardware configuration of the access point according to the embodiment. [Figure 4] FIG. 4 is a block diagram showing a hardware configuration of a terminal according to the embodiment. [Figure 5] FIG. 5 is a block diagram showing the functional configuration of the access point and the terminal according to the embodiment. [Figure 6] FIG. 6 is a diagram illustrating a channel access function of the terminal according to the embodiment. [Figure 7] FIG. 7 is a diagram illustrating a transmission process in the terminal according to the embodiment. [Figure 8] FIG. 8 is a diagram illustrating a situation in which the frame exchange period is shorter than the communication enabled period according to the embodiment. [Figure 9] FIG. 9 is a diagram illustrating a situation in which the frame exchange period is longer than the communication enabled period according to the embodiment. [Figure 10] FIG. 10 is a flowchart showing a wireless communication method according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0015] Multi-link operation is being considered for IEEE802.11be, which is currently being developed as the successor standard to IEEE802.11ax. Multi-link operation specifies a mechanism for logically establishing multiple links using different frequency channels between an access point and a terminal device. In multi-link operation, the access point and terminal device wirelessly communicate with each other using the established links. For example, the terminal device performs carrier sensing based on CSMA / CA for each link and wirelessly transmits a data frame to the access point over the link for which it has acquired the right to transmit. The access point is also called a base station. Hereinafter, the terminal device will be simply called a terminal, and the frequency channel will be simply called a channel.

[0016] The access point and terminal according to the embodiments described below support multilink operation and establish multiple links between the access point and the terminal. The multiple links established between the access point and the terminal are called multilinks (MLs). The access point and terminal further support r-TWT operation. The access point schedules r-TWT service periods for each terminal, during which a transmission opportunity is granted or allocated. During the r-TWT service period, each terminal can prioritize data frame transmission on the link for which the r-TWT service period is set. Each terminal can use the r-TWT service period to transmit data frames including traffic with delay requirements.

[0017] In one embodiment, when r-TWT service periods are scheduled for all links included in the multilink, the terminal wirelessly transmits data frames to the access point, for example, using the following procedure. The terminal performs carrier sensing on multiple channels corresponding to each of the multiple links included in the multilink to confirm the status of these links. The terminal determines that a channel is idle when it has not been used for a specific time period, and determines that the channel is busy when it detects that the channel is being used. In response to confirming that the channel is idle, the terminal recognizes that it has acquired the transmission right for the link corresponding to the channel. After acquiring the transmission right for the multiple links, the terminal checks whether data frame transmission can be completed by the start of the r-TWT service period for each link for which it has acquired the transmission right. If there is a link for which data frame transmission can be completed by the start of the r-TWT service period, the terminal transmits the data frame on that link. If there is no link for which data frame transmission can be completed by the start of the r-TWT service period, the terminal postpones transmission. For example, the terminal may transmit a data frame on any link after the r-TWT service period for that link has ended.

[0018] According to the above configuration, even if data frame transmission cannot be completed on a certain link by the start of the r-TWT service period set for that link, data frame transmission can be performed on another link. This reduces the frequency of transmission postponement due to the r-TWT service period, and effectively prevents collisions and a decrease in frequency utilization efficiency. As a result, throughput and delay characteristics are improved.

[0019] 1 is a schematic diagram illustrating an example of a configuration of a communication system 50 including a wireless network 45 according to one embodiment. The terms "system" and "network" used herein may be used interchangeably. As shown in FIG. 1 , the communication system 50 includes an access point 10, a terminal 20, and a server 30. The access point 10 and the terminal 20 are included in the wireless network 45.

[0020] The access point 10 is an access point of a wireless LAN. The access point 10 can be wirelessly connected to one or more terminals. The number of terminals wirelessly connected to the access point 10 changes dynamically. In the example shown in FIG. 1 , the access point 10 is wirelessly connected to the terminal 20. The access point 10 establishes one or more links with the terminal 20 and wirelessly communicates with the terminal 20 using the established links. The access point 10 is connected by wire to a communication network 40 that may include the Internet.

[0021] The terminal 20 is a wireless terminal equipped with a wireless communication function and operates as a client of a wireless LAN. Examples of wireless terminals include a smartphone, a mobile phone, a tablet PC (personal computer), a desktop PC, a laptop PC, and an IoT (Internet of Things) sensor / device. The terminal 20 accesses a communication network 40 via an access point 10. For example, the terminal 20 exchanges data with a server 30 on the communication network 40 via the access point 10.

[0022] The server 30 is connected to a communication network 40. For example, the server 30 may be a service provider that provides a service such as a network game, and exchanges data related to the service with the terminal 20 via the communication network 40.

[0023] The wireless communication between the access point 10 and the terminal 20 is based on the IEEE 802.11 standard. Although the present specification describes wireless communication based on the IEEE 802.11 standard as an example, a wireless communication standard other than the IEEE 802.11 standard may also be used.

[0024] The access point 10 and the terminal 20 support multilink operation and r-TWT operation. The access point 10 that supports multilink operation is also called an access point multilink device (AP MLD), and the terminal 20 that supports multilink operation is also called a non-access point multilink device (non-AP MLD).

[0025] The IEEE 802.11 standard defines Layer 1 and Layer 2 (MAC) sublayer of the Open Systems Interconnection (OSI) model. In the OSI model, communication functions 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, and Layer 7: Application Layer). The data link layer includes, for example, a logical link control (LLC) layer and a MAC layer. The LLC layer forms LLC packets by adding a destination service access point (DSAP) header and a source service access point (SSAP) header to data input from a higher layer. The MAC layer generates MAC frames by adding a MAC header to LLC packets. The physical layer generates wireless frames by adding a preamble and a physical layer (PHY) header to MAC frames. Here, the description will be focused on the processing of the first layer and the MAC sublayer of the second layer defined by the IEEE 802.11 standard, and the description of the processing of other layers will be omitted.

[0026] Fig. 2 shows an example of link management information held by the terminal 20. The link management information shown in Fig. 2 indicates the status of the link between the access point 10 and the terminal 20. The link management information includes a link ID, frequency band information, a channel ID, link information, multi-link information, and traffic information.

[0027] A link ID is an identifier (e.g., an identification number) assigned to a link. Frequency band information is information indicating a frequency band used for a link. A channel ID is an identifier of a channel used for a link. In the example shown in FIG. 2, terminal 20 can use three links. A link with link ID 1 is a link that uses a channel in the 6 GHz band, and is currently using channel CH1 included in the 6 GHz band. A link with link ID 2 is a link that uses a channel in the 5 GHz band, and is currently using channel CH2 included in the 5 GHz band. A link with link ID 3 is a link that uses a channel in the 2.4 GHz band, and is currently using channel CH3 included in the 2.4 GHz band. Note that different frequency bands may be assigned to multiple links of a multilink ML, or different channels in the same frequency band may be assigned to multiple links.

[0028] The link information indicates whether or not a link has been established between the access point 10 and the terminal 20. The multilink information indicates whether or not a multilink ML consisting of a plurality of links has been established between the access point 10 and the terminal 20. If a multilink ML has been established, the multilink information indicates which links make up the multilink ML. In the example shown in FIG. 2, the multilink ML is made up of three links with link IDs 1 to 3.

[0029] The traffic information indicates a TID (Traffic Indicator) assigned to each link. A TID is an identifier indicating each type of traffic, and each type of traffic may be associated with an access category. The access categories include, for example, VO (Voice), VI (Video), BE (Best Effort), and BK (Background). TID#1, TID#2, TID#3, and TID#4 shown in FIG. 2 correspond to VO, VI, BE, and BK, respectively. In the example shown in FIG. 2, TID#1 is assigned to three links with link IDs 1 to 3. TID#2 is assigned to the link with link ID 1, TID#3 is assigned to the link with link ID 2, and TID#4 is assigned to the link with link ID 3. In this way, in multi-link ML, one or more links can be assigned to one TID.

[0030] The access point 10 holds link management information similar to the link management information exemplified in Fig. 2 for each terminal wirelessly connected to the access point 10. In other words, the link management information held by the access point 10 indicates the status of the link between the access point 10 and each terminal wirelessly connected to the access point 10.

[0031] Fig. 3 schematically illustrates an example of the hardware configuration of the access point 10. As illustrated in Fig. 3, the access point 10 includes, for example, a CPU (Central Processing Unit) 11, a program memory 12, a RAM (Random Access Memory) 13, a wireless communication module 14, and a wired communication module 15.

[0032] The CPU 11 is an integrated circuit capable of executing various programs and controls the overall operation of the access point 10. The program memory 12 is a non-volatile semiconductor memory such as a ROM (read only memory) or a flash memory, and stores programs and control data for controlling the access point 10. The RAM 13 is, for example, a volatile semiconductor memory, and is used as a work area for the CPU 11. The wireless communication module 14 is a circuit used to send and receive data via wireless signals. The wireless communication module 14 includes multiple communication modules corresponding to multiple links, and each communication module is connected to an antenna corresponding to the communication module among multiple antennas. The wireless communication module 14 can simultaneously send and receive frames via multiple links. The wired communication module 15 is a circuit used to send and receive data via wired signals, and is connected to the communication network 40.

[0033] Fig. 4 schematically illustrates an example of the hardware configuration of the terminal 20. As illustrated in Fig. 4, the terminal 20 includes, for example, a CPU 21, a program memory 22, a RAM 23, a wireless communication module 24, a display 25, and a storage 26.

[0034] The CPU 21 is an integrated circuit capable of executing various programs and controls the overall operation of the terminal 20. The program memory 22 is a non-volatile semiconductor memory such as a ROM, and stores programs and control data for controlling the terminal 20. The storage 26 may be used as the program memory 22. The RAM 23 is, for example, a volatile semiconductor memory, and is used as a work area for the CPU 21. The wireless communication module 24 is a circuit used to transmit and receive data via wireless signals. The wireless communication module 24 includes multiple communication modules corresponding to multiple links, and each communication module is connected to an antenna corresponding to the communication module among multiple antennas. The wireless communication module 24 can simultaneously transmit and receive frames via multiple links. The display 25 displays information such as a GUI (Graphical User Interface) provided by application software. The display 25 may also function as an input interface for the terminal 20. For example, a touch panel may be provided on the display 25. The storage 26 is a non-volatile storage device and stores data including, for example, system software for the terminal 20.

[0035] The hardware configuration shown in Fig. 4 is an example, and the terminal 20 may have a hardware configuration different from that shown in Fig. 4. For example, if the terminal 20 is an IoT device or the like, the display 25 may be removed from the terminal 20.

[0036] 5 shows an example of a functional configuration of the access point 10 and the terminal 20. Here, processing related to uplink transmission will be mainly described, and a detailed description of processing related to downlink transmission will be omitted. Downlink transmission can be performed in the same manner as the processing described for uplink transmission. For example, the access point 10 can perform modulation processing similar to the modulation processing described later in relation to the terminal 20, and the terminal 20 can perform demodulation processing similar to the demodulation processing described later in relation to the access point 10. Uplink transmission refers to transmission from the terminal 20 to the access point 10, and downlink transmission refers to transmission from the access point 10 to the terminal 20.

[0037] 5, the access point 10 includes an LLC processing unit 110, a link management unit 120, and a communication unit 130. The LLC processing unit 110 can be realized by a combination of a CPU 11 and a wired communication module 15. The link management unit 120 and the communication unit 130 can be realized by a wireless communication module 14 or a combination of the CPU 11 and the wireless communication module 14.

[0038] The LLC processing unit 110 performs LLC layer processing and upper layer (layers 3 to 7) processing on the input signal. For example, the LLC processing unit 110 receives an LLC packet from the link management unit 120 and extracts data from the LLC packet.

[0039] The link management unit 120 performs MAC layer processing on the input signal. Furthermore, the link management unit 120 manages links with each terminal. The link management unit 120 includes a data processing unit 121, a MAC frame processing unit 122, and a management unit 123.

[0040] The data processing unit 121 receives a MAC frame from the MAC frame processing unit 122 , extracts an LLC packet from the MAC frame, and sends the LLC packet to the LLC processing unit 110 .

[0041] When the MAC frame processing unit 122 receives a MAC frame from the communication unit 130, it sends the MAC frame to the data processing unit 121 or the management unit 123 depending on the type of the MAC frame. Specifically, if the MAC frame is a data frame, the MAC frame processing unit 122 sends the MAC frame to the data processing unit 121, and if the MAC frame is a management frame or a control frame, it sends the MAC frame to the management unit 123.

[0042] The management unit 123 manages links with each terminal based on information included in a management frame transmitted by each terminal. For example, the management unit 123 sets up a multilink with the terminal via the communication unit 130. Specifically, in response to receiving a connection request from the terminal 20, the management unit 123 executes an association process and a subsequent authentication process to establish multiple links between the access point 10 and the terminal 20. Data is exchanged between the access point 10 and the terminal 20 using one or more links included in the multilink. The management unit 123 holds link management information such as that shown in FIG. 2. The access point 10 may negotiate with the terminal 20 an MCS (Modulation and Coding Scheme) to be used for communication between the access point 10 and the terminal 20.

[0043] The management unit 123 sets up r-TWT for each terminal that supports r-TWT operation. For example, the management unit 123 sets an r-TWT service period and a link to be used during the r-TWT service period. The management unit 123 may set the r-TWT service period according to the period during which low-latency traffic occurs in the terminal. Specifically, the management unit 123 determines the start time of the r-TWT service period, the period of the r-TWT service period, and the duration of the r-TWT service period based on the period during which low-latency traffic occurs so that the r-TWT service period occurs in synchronization with the occurrence of low-latency traffic. The management unit 123 may acquire the period during which low-latency traffic occurs using any method. In one example, the management unit 123 may acquire a data generation period set in an application that generates low-latency traffic. The management unit 123 may dynamically determine the link to be used during the r-TWT service period for each r-TWT service period.

[0044] The management unit 123 generates a beacon frame including service period information that specifies the r-TWT service period set for each terminal, and transmits the beacon frame via the MAC frame processing unit 122 and the communication unit 130. The beacon frame is a type of management frame. The service period information may include information indicating the time when the r-TWT service period starts, information indicating the duration of the r-TWT service period, information indicating the cycle of the r-TWT service period, and information indicating the link to be used during the r-TWT service period. The service period information may further include information indicating a communication suspension period (quiet period) during which terminals other than the terminal for which the r-TWT service period is set are restricted from communicating. The start of the communication suspension period coincides with the start of the r-TWT service period. The communication suspension period may be shorter than the r-TWT service period.

[0045] The communication unit 130 wirelessly communicates with each terminal. The communication unit 130 includes a radio signal processing unit 131 configured to transmit and receive radio signals using a 6 GHz channel, a radio signal processing unit 132 configured to transmit and receive radio signals using a 5 GHz channel, and a radio signal processing unit 133 configured to transmit and receive radio signals using a 2.4 GHz channel. The radio signal processing unit 131 transmits and receives frames between the access point 10 and the terminal via wireless communication. Specifically, the radio signal processing unit 131 performs physical layer processing on input data or radio signals. For example, the radio signal processing unit 131 receives radio signals from the terminal via an antenna and performs predetermined demodulation processing on the received radio signals to obtain radio frames. The predetermined demodulation processing includes, for example, frequency conversion, OFDM demodulation, fast Fourier transform (FFT), subcarrier demodulation, deinterleaving, and Viterbi decoding. The radio signal processing unit 131 then extracts MAC frames from the radio frames and sends the MAC frames to the MAC frame processing unit 122. The radio signal processing units 132 and 133 perform the same processing as the radio signal processing unit 131 .

[0046] The terminal 20 includes an application execution unit 210, an LLC processing unit 220, a link management unit 230, and a communication unit 240. The application execution unit 210 and the LLC processing unit 220 may be realized by a CPU 21. The link management unit 230 and the communication unit 240 may be realized by a wireless communication module 24 or a combination of the wireless communication module 24 and the CPU 21.

[0047] The application execution unit 210 executes applications such as an application that exchanges data with the server 30 shown in Fig. 1. The LLC processing unit 220 performs LLC layer and upper layer processing on input data. For example, the LLC processing unit 220 receives data from the application execution unit 210, adds a DSAP header, an SSAP header, and the like to the data to generate an LLC packet, and sends the LLC packet to the link management unit 230.

[0048] The link management unit 230 performs MAC layer processing on the input signal. Furthermore, the link management unit 230 manages the link with the access point 10. The link management unit 230 includes a data processing unit 231, a MAC frame processing unit 232, a management unit 233, and a communication control unit 234.

[0049] The data processing unit 231 receives an LLC packet from the LLC processing unit 220, adds a MAC header to the LLC packet to generate a MAC frame, and sends the MAC frame to the MAC frame processing unit 232. This MAC frame is a data frame.

[0050] The MAC frame processing unit 232 receives a MAC frame from the data processing unit 231 and sends it to the communication unit 240. Furthermore, when the MAC frame processing unit 232 receives a MAC frame from the communication unit 240, it sends the MAC frame to the data processing unit 231 or the management unit 233 depending on the type of MAC frame. Specifically, if the MAC frame is a data frame, the MAC frame processing unit 232 sends the MAC frame to the data processing unit 231, and if the MAC frame is a management frame or a control frame, it sends the MAC frame to the management unit 233.

[0051] The management unit 233 manages the link with the access point 10 based on information included in a management frame transmitted by the access point 10. For example, the management unit 233 sets up a multi-link with the access point 10 via the communication unit 240. Specifically, the management unit 233 executes a protocol related to association, which includes transmitting a connection request to the access point 10, and executes a protocol related to authentication subsequent to the association. The management unit 233 holds link management information such as that shown in FIG. 2. The link management information is referenced by the communication control unit 234.

[0052] The management unit 233 extracts service period information that specifies the r-TWT service period set for each terminal from the beacon frame transmitted by the access point 10, and sends the extracted service period information to the communication control unit 234.

[0053] The communication control unit 234 controls the operation of the communication unit 240. For example, the communication control unit 234 adaptively selects a link to be used for communication with the access point 10. Furthermore, the communication control unit 234 adjusts the timing of transmitting data frames to the access point 10. The communication control unit 234 will be described in detail later.

[0054] The communication unit 240 wirelessly communicates with the access point 10 under the control of the communication control unit 234. The communication unit 240 includes a radio signal processing unit 241 configured to transmit and receive radio signals using a 6 GHz band channel, a radio signal processing unit 242 configured to transmit and receive radio signals using a 5 GHz band channel, and a radio signal processing unit 243 configured to transmit and receive radio signals using a 2.4 GHz band channel. The radio signal processing unit 241 transmits and receives frames between the access point 10 and the terminal 20 via wireless communication. Specifically, the radio signal processing unit 241 performs physical layer processing on input data or radio signals. For example, the radio signal processing unit 241 receives a MAC frame from the MAC frame processing unit 232, adds a preamble and a PHY (physical layer) header to the MAC frame to generate a radio frame, converts the radio frame into a radio signal by performing a predetermined modulation process, and emits the radio signal via an antenna. The modulation processing includes, for example, convolutional coding, interleaving, subcarrier modulation, inverse fast Fourier transform (IFFT), orthogonal frequency division multiplexing (OFDM) modulation, and frequency conversion. The radio signal processing units 242 and 243 perform the same processing as the radio signal processing unit 241.

[0055] The process for transmitting data frames on the uplink will now be briefly described.

[0056] When an application generates data to be sent to server 30 (shown in FIG. 1), application execution unit 210 sends the data to LLC processing unit 220. LLC processing unit 220 receives the data from application execution unit 210, creates an LLC packet containing the data, and sends the LLC packet to data processing unit 231.

[0057] The data processing unit 231 receives LLC packets from the LLC processing unit 220, generates MAC frames from the LLC packets, and sends the MAC frames to the MAC frame processing unit 232. The MAC frame processing unit 232 receives MAC frames from the data processing unit 231 and sends the MAC frames to the communication unit 240. The MAC frame processing unit 232 sends the MAC frames to multiple radio signal processing units corresponding to the multiple links included in the multilink. The MAC frame processing unit 232 refers to link management information held by the management unit 233 to identify links established with the access point 10. When the link management information is the link management information shown in FIG. 2, three links are established between the access point 10 and the terminal 20.

[0058] The communication unit 240 receives a MAC frame from the MAC frame processing unit 232 and temporarily stores the MAC frame. The communication unit 240 transmits the MAC frame wirelessly in accordance with instructions from the communication control unit 234. In the communication unit 240, the radio signal processing units 241, 242, and 243 receive the same MAC frame from the MAC frame processing unit 232, and one of them transmits the MAC frame wirelessly, while the remaining radio signal processing units discard the MAC frame. For example, if the communication control unit 234 determines to use a link with a link ID of 1, the radio signal processing unit 241 generates a radio frame from the MAC frame, converts the radio frame into a radio signal by performing modulation processing, and emits the radio signal via an antenna.

[0059] In the access point 10, the communication unit 130 receives a wireless signal from the terminal 20. One of the wireless signal processing units 131, 132, and 133 receives the wireless signal from the terminal 20. For example, when the terminal 20 uses a link with a link ID of 1, the wireless signal processing unit 131 receives the wireless signal from the terminal 20. The wireless signal processing unit 131 performs demodulation processing on the wireless signal to obtain a wireless frame. The wireless signal processing unit 131 extracts a MAC frame from the wireless frame and sends the MAC frame to the MAC frame processing unit 122.

[0060] The MAC frame processing unit 122 receives a MAC frame from the communication unit 130. Since this MAC frame is a data frame, the MAC frame processing unit 122 sends the MAC frame to the data processing unit 121.

[0061] The data processing unit 121 receives a MAC frame from the MAC frame processing unit 122, extracts an LLC packet from the MAC frame, and sends the LLC packet to the LLC processing unit 110. The LLC processing unit 110 receives the LLC packet from the data processing unit 121, extracts data from the LLC packet, and transmits the data to the server 30 on the communication network 40.

[0062] 6 schematically illustrates an example of the functional configuration of the channel access function of the radio signal processing unit 241. As illustrated in FIG. 6, the radio signal processing unit 241 includes a classification unit 2411, queues 2412A, 2412B, 2412C, and 2412D, carrier sense execution units 2413A, 2413B, 2413C, and 2413D, an internal collision management unit 2414, and a modulation unit 2415.

[0063] When a data frame is input to the radio signal processing unit 241, the classification unit 2411 classifies the data frame into a plurality of access categories based on the TID included in the MAC header of the data frame. In the example shown in Fig. 6, the classification unit 2411 classifies the data frame into four access categories: VO, VI, BE, and BK.

[0064] Classification unit 2411 inputs a data frame to queue 2412A if the data frame is classified into access category VO, inputs the data frame to queue 2412B if the data frame is classified into access category VI, inputs the data frame to queue 2412C if the data frame is classified into access category BE, and inputs the data frame to queue 2412D if the data frame is classified into access category BK. Each of queues 2412A, 2412B, 2412C, and 2412D buffers the input data frames.

[0065] The carrier sense execution units 2413A, 2413B, 2413C, and 2413D are provided corresponding to the queues 2412A, 2412B, 2412C, and 2412D, respectively. The carrier sense execution units 2413A, 2413B, 2413C, and 2413D perform similar processing except for using different access parameter sets. The access parameter set includes four access parameters, for example, CWmin, CWmax, AIFS (Arbitration Inter Frame Space), and TXOP (Transmission Opportunity) Limit. CWmin and CWmax indicate the minimum and maximum values ​​of the contention window, respectively. The contention window is a parameter used to determine the transmission waiting time for collision avoidance. AIFS indicates the transmission waiting time. TXOPLimit indicates the upper limit of the channel occupation period TXOP. In other words, the shorter the CWmin, CWmax, and AIFS set for an access category, the easier it is to obtain the transmission right. Furthermore, the larger the TXOPLimit set for an access category, the larger the amount of data that can be transmitted with one transmission right.

[0066] The carrier sense execution unit 2413A will be described as a representative example. The carrier sense execution unit 2413A executes carrier sense based on CSMA / CA in accordance with a preset access parameter set for a link with a link ID of 1. When the carrier sense execution unit 2413A starts carrier sense, it notifies the communication control unit 234 of the carrier sense status. For example, when a channel has been unused for a long period of time, the carrier sense execution unit 2413A notifies the communication control unit 234 of the scheduled time when the transmission right will be acquired and the channel occupation time. When the carrier sense execution unit 2413A detects that the channel is busy, it notifies the communication control unit 234 that carrier sense will be discontinued.

[0067] When the carrier sense execution unit 2413A acquires the transmission right, it notifies the communication control unit 234 that the transmission right has been acquired. In response to the notification from the carrier sense execution unit 2413A, the communication control unit 234 sends to the carrier sense execution unit 2413A a transmission start signal instructing the start of transmission, a transmission postponement signal instructing the postponement of transmission, or a transmission halt signal indicating that data frame transmission will be performed on another link (radio signal processing unit 242 or 243). In response to receiving a transmission instruction signal from the communication control unit 234, the carrier sense execution unit 2413A retrieves a data frame from the queue 2412A and sends the data frame to the modulation unit 2415 via the internal collision management unit 2414. In response to receiving a transmission postponement signal from the communication control unit 234, the carrier sense execution unit 2413A postpones transmission. For example, the carrier sense execution unit 2413A waits until it receives a signal instructing the restart of carrier sense from the communication control unit 234. In response to receiving a transmission stop signal from the communication control unit 234, the carrier sense execution unit 2413A discards the data frame stored at the head of the queue 2412A.

[0068] The internal collision management unit 2414 prevents transmission collisions when two or more carrier sense execution units simultaneously acquire the transmission right. Specifically, when the internal collision management unit 2414 receives data frames from two or more carrier sense execution units simultaneously, it sends the data frame of the higher priority access category to the modulation unit 2415 in order to transmit the data frame of the higher priority access category.

[0069] The modulation unit 2415 receives the data frame from the internal collision management unit 2414, generates a radio frame from the data frame, converts the radio frame into a radio signal by performing modulation processing, and emits the radio signal via an antenna.

[0070] Each of the radio signal processing units 242 and 243 has a channel access function similar to that shown in FIG.

[0071] 7, data frame transmission in terminal 20 will be described in detail. Here, transmission of data frames classified into access category VO will be described. Data frames classified into other access categories can be transmitted in the same manner as described below.

[0072] Fig. 7 schematically shows an example of the functional configuration of the communication control unit 234 and the radio signal processing units 241, 242, and 243. Fig. 7 shows part of the functional configuration of each of the radio signal processing units 241, 242, and 243. For example, with respect to the radio signal processing unit 241, the classification unit 2411, queues 2412B, 2412C, and 2412D, carrier sense execution units 2413B, 2413C, and 2413D, internal collision management unit 2414, and modulation unit 2415 shown in Fig. 6 are omitted.

[0073] As shown in FIG. 7, the radio signal processing unit 242 includes a queue 2422A and a carrier sense execution unit 2423A. The queue 2422A buffers data frames classified into the access category VO. The carrier sense execution unit 2423A performs carrier sensing based on CSMA / CA for the link with a link ID of 2, in accordance with the same access parameter set as that of the carrier sense execution unit 2413A. The radio signal processing unit 243 includes a queue 2432A and a carrier sense execution unit 2433A. The queue 2432A buffers data frames classified into the access category VO. The carrier sense execution unit 2433A performs carrier sensing based on CSMA / CA for the link with a link ID of 3, in accordance with the same access parameter set as that of the carrier sense execution unit 2413A. Since the MAC frame processing unit 232 sends each data frame to the radio signal processing units 241, 242, and 243, the same data frame is stored in the queues 2412A, 2422A, and 2432A.

[0074] The carrier sense execution units 2413A, 2423A, and 2433A may perform carrier sense simultaneously. As a result, transmission rights may be acquired for multiple links simultaneously. When each of the carrier sense execution units 2413A, 2423A, and 2433A acquires the transmission right, it notifies the communication control unit 234 that it has acquired the transmission right. The carrier sense execution units 2413A, 2423A, and 2433A are collectively referred to as carrier sense execution unit 245.

[0075] The communication control unit 234 includes an instruction unit 2341 , a link selection unit 2342 , a frame exchange period calculation unit 2343 , a communication available period calculation unit 2344 , and a determination unit 2345 .

[0076] The instruction unit 2341 exchanges information with the carrier sense execution unit 245. For example, the instruction unit 2341 issues instructions to the carrier sense execution units 2413A, 2423A, and 2433A. The instruction unit 2341 also receives notifications from the carrier sense execution units 2413A, 2423A, and 2433A indicating that the transmission right has been acquired, and sends the received notifications to the communication possible period calculation unit 2344.

[0077] The frame exchange period calculation unit 2343 calculates a frame exchange period including a time period required to transmit a data frame to the access point 10. The frame exchange period indicates a time period required for frame exchange between the access point 10 and the terminal 20. The frame exchange period may indicate a period from the time when the transmission right is acquired to the time when processing related to transmitting a data frame to the access point 10 is completed, as indicated by α in FIG. 8 . The processing related to transmitting a data frame to the access point 10 may indicate processing for transmitting a data frame to the access point 10, or may indicate a series of processing for transmitting a data frame to the access point 10 and receiving a response to the data frame (e.g., an ACK, which is an acknowledgment) from the access point 10. In other words, the frame exchange period may indicate a time period required to transmit a data frame to the access point 10, or may indicate a time period required to transmit a data frame to the access point 10 and receive a response to the data frame from the access point 10.

[0078] For example, the frame exchange period calculation unit 2343 receives information indicating the size of the data frame to be transmitted (the data frame held at the top of the queue 2412A) from the carrier sense execution unit 2413A via the instruction unit 2341, and receives information indicating the MCS to be applied to the data frame transmission to the access point 10 from the management unit 233. The frame exchange period calculation unit 2343 calculates the time period required to transmit the data frame to the access point 10 based on the size of the data frame to be transmitted, the MCS to be applied to the data frame transmission, and the transmission waiting time calculated using the average back-off value determined by the contention window. The transmission waiting time calculated using the average back-off value determined by the contention window corresponds to the overhead related to obtaining the transmission right.

[0079] The communication available period calculation unit 2344 receives a notification from the carrier sense execution unit 245 via the instruction unit 2341 indicating one or more links for which the transmission right has been acquired. The communication available period calculation unit 2344 calculates a communication available period indicating the time period until the start of the r-TWT service period for each link for which the transmission right has been acquired. The communication available period may indicate the period from the time the transmission right is acquired to the time the r-TWT service period starts, as indicated by β in FIG. 8. The communication available period calculation unit 2344 checks whether an r-TWT service period has been scheduled for the link. The r-TWT service period may be set for the terminal 20 or may be set for another terminal. If the r-TWT service period is set for another terminal, the start of the r-TWT service period indicates the start of the communication suspension period.

[0080] When an r-TWT service period is scheduled for all links for which a transmission right has been acquired, the communication period calculation unit 2344 calculates a communication period for each of these links. When an r-TWT service period is not scheduled for any link, the communication period calculation unit 2344 notifies the link selection unit 2342 of the link for which an r-TWT service period is not scheduled. Alternatively, even when an r-TWT service period is not scheduled for any link, the communication period calculation unit 2344 may calculate a communication period for all links for which a transmission right has been acquired. In this case, the communication period calculation unit 2344 may set the communication period for the link for which an r-TWT service period is not scheduled to a value indicating a sufficiently long period.

[0081] For each link for which the transmission right has been acquired, the determination unit 2345 determines whether or not data exchange including transmission of data frames to the access point 10 will be completed by the start of the r-TWT service period, based on a comparison between the frame exchange period calculated by the frame exchange period calculation unit 2343 and the communication period calculated by the communication period calculation unit 2344. If the frame exchange period α is shorter than the communication period β as shown in Fig. 8, the determination unit 2345 determines that the data exchange will be completed by the start of the r-TWT service period, and if the frame exchange period α is longer than the communication period β as shown in Fig. 9, the determination unit 2345 determines that the data exchange will not be completed by the start of the r-TWT service period.

[0082] The determination unit 2345 notifies the instruction unit 2341 or the link selection unit 2342 of the determination result. If there are one or more links whose frame exchange period α is shorter than the communication available period β, the determination unit 2345 sends a determination result notification to the link selection unit 2342. If there is one link whose frame exchange period α is shorter than the communication available period β, the determination result notification includes information indicating that link. If there are multiple links whose frame exchange period α is shorter than the communication available period β, the determination result notification includes information indicating the link whose difference, obtained by subtracting the frame exchange period α from the communication available period β, is the largest. If there are no links whose frame exchange period α is shorter than the communication available period β, the determination unit 2345 sends a determination result notification to the instruction unit 2341 indicating that there are no links whose data exchange will be completed by the start of the r-TWT service period.

[0083] The link selection unit 2342 receives a determination result notification from the determination unit 2345, selects a link from the multiple links to be used for transmitting a data frame to the access point 10 based on the determination result notification, and notifies the instruction unit 2341 of the selected link. Specifically, the link selection unit 2342 selects the link indicated by the determination result notification. If the determination result notification indicates multiple links, the link selection unit 2342 selects one of those links. If the link selection unit 2342 receives a notification from the communication available period calculation unit 2344, it selects a link based on the notification and notifies the instruction unit 2341 of the selected link. For example, the link selection unit 2342 selects the link indicated by the notification from the communication available period calculation unit 2344.

[0084] If there are multiple links whose frame exchange period α is shorter than the communication period β, the determination result notification may include information indicating the multiple links whose frame exchange period α is shorter than the communication period β. In this case, the link selection unit 2342 selects one of the links.

[0085] In response to receiving a notification from the link selection unit 2342, the instruction unit 2341 instructs the carrier sense execution unit 245 to transmit a data frame via the link selected by the link selection unit 2342. For example, if the link selection unit 2342 selects a link with a link ID of 2, the instruction unit 2341 sends a transmission start signal to the carrier sense execution unit 2423A and sends a transmission stop signal to the carrier sense execution units 2413A and 2433A. In response to receiving a determination result notification from the determination unit 2345, the instruction unit 2341 instructs the carrier sense execution unit 245 to postpone the data frame transmission. Specifically, the instruction unit 2341 sends a transmission postponement signal to the carrier sense execution units 2413A, 2423A, and 2433A.

[0086] The instructing unit 2341, the link selecting unit 2342, and the determining unit 2345 may be collectively referred to as the transmission control unit 2346. If there is a link whose frame exchange period α is shorter than the communication period β, the transmission control unit 2346 is configured to transmit data frames on that link via the communication unit 240, and if there is no link whose frame exchange period α is shorter than the communication period β, postpone the data frame transmission. If there are multiple links whose frame exchange period α is shorter than the communication period β, the transmission control unit 2346 may be configured to transmit data frames on the link whose difference between the communication period β and the frame exchange period α is the largest. The link whose difference between the communication period β and the frame exchange period α is the largest corresponds to the link whose communication period β is the longest. The transmission control unit 2346 may be configured to transmit data frames on the link in response to the presence of a link whose service period is not scheduled.

[0087] Fig. 10 schematically illustrates a wireless communication method according to one embodiment. Specifically, Fig. 10 schematically illustrates an example of a method in which a terminal 20 wirelessly transmits a data frame to an access point 10. The processing illustrated in Fig. 10 is performed individually for each access category. Here, the processing for access category VO will be described. Let M be the number of links established between the access point 10 and the terminal 20.

[0088] 10, the frame exchange period calculation unit 2343 calculates a frame exchange period α that includes the time period required to transmit a data frame to the access point 10. For example, the frame exchange period calculation unit 2343 calculates the time period required to transmit a data frame to the access point 10 based on the size of the data frame to be transmitted and the MCS to be applied to the data frame transmission, and obtains the frame exchange period α by adding the time required to receive an ACK from the access point 10 and the overhead related to obtaining the transmission right to the calculated time period.

[0089] In step S1002, carrier sense execution unit 245 performs carrier sense on each of M links and acquires transmission rights for m links. Here, m is an integer between 2 and M. The m links for which transmission rights have been acquired are represented as links 1 to m. In the example shown in FIG. 7, carrier sense execution unit 2413A performs carrier sense on the link with link ID 1, carrier sense execution unit 2423A performs carrier sense on the link with link ID 2, and carrier sense execution unit 2433A performs carrier sense on the link with link ID 3.

[0090] In step S1003, the communication period calculation unit 2344 calculates the communication period β for each of the links 1 to m. Here, it is assumed that the r-TWT service period is scheduled for all of the links 1 to m. The communication period β for the link N is calculated as β N Here, N is an integer between 1 and m. N may indicate the time interval from the reference time to the start time of the r-TWT service period set for link N. The reference time indicates the time when data frame transmission can start. The time when the transmission right for link N is acquired can be used as the reference time.

[0091] In step S1004, the determination unit 2345 determines whether there is a link whose frame exchange period α is shorter than the communication available period β. N indicates that the frame exchange is completed before the start of the r-TWT service period scheduled for link N.

[0092] If there is no link whose frame exchange period α is shorter than the communication available period β (step S1004; No), the process proceeds to step S1007. In step S1007, the transmission control unit 2346 postpones the data frame transmission. For example, the determination unit 2345 notifies the instruction unit 2341 that there is no link whose frame exchange can be completed before the start of the r-TWT service period, and the instruction unit 2341 sends a transmission postponement signal to the carrier sense execution unit 245 in response to the notification from the determination unit 2345.

[0093] If there is a link whose frame exchange period α is shorter than the communication period β (step S1004; Yes), the process proceeds to step S1005. In step S1005, the link selection unit 2342 selects the link whose difference when the frame exchange period α is subtracted from the communication period β is the largest. In other words, the link selection unit 2342 selects the link whose communication period β is the longest. For example, if the communication periods β1 and β2 for links 1 and 2 are both shorter than the frame exchange period α (α<β1, α<β2), and the difference when the frame exchange period α is subtracted from the communication period β1 (β1-α) is greater than the difference when the frame exchange period α is subtracted from the communication period β2 (β2-α), link 1 is selected. If the difference when the frame exchange period α is subtracted from the communication period β1 (β1-α) is smaller than the difference when the frame exchange period α is subtracted from the communication period β2 (β2-α), link 2 is selected.

[0094] In step S1006, the transmission control unit 2346 transmits the data frame via the link selected in step S1005 via the communication unit 240. Specifically, the instruction unit 2341 instructs the carrier sense execution unit 245 to transmit the data frame via the selected link. For example, in the example shown in FIG. 7, if link 1 is selected in step S1005, the instruction unit 2341 sends a transmission start signal to the carrier sense execution unit 2413A and sends transmission stop signals to the carrier sense execution units 2423A and 2433A. In response to receiving the transmission start signal from the instruction unit 2341, the carrier sense execution unit 2413A retrieves the data frame from the queue 2412A and sends the data frame to the modulation unit 2415 via the internal collision management unit 2414. The modulation unit 2415 performs modulation processing on the data frame to generate a radio signal and transmits the radio signal via an antenna. In response to receiving the transmission stop signal from the instruction unit 2341, the carrier sense execution units 2423A and 2433A discard the data frame stored at the top of the queues 2422A and 2432A.

[0095] 10 is merely an example. For example, in step S1003, if an r-TWT service period is not scheduled for one or more of links 1 to m, the communication period calculation unit 2344 may set the communication period β for each link for which an r-TWT service period is not scheduled to a predetermined value indicating a sufficiently long period. In this case, data frame transmission will be performed on the link for which an r-TWT service period is not scheduled.

[0096] Furthermore, if an r-TWT service period is not scheduled for one or more of links 1 to m, the process may skip steps S1003 to S1005 and proceed to step S1006. In this case, data frame transmission will also be performed on the links for which an r-TWT service period is not scheduled.

[0097] In step S1005, the link selection unit 2342 may select a link other than the link with the largest difference between the frame exchange period α and the communication period β, if the frame exchange period α is shorter than the communication period β. Specifically, if there are multiple links with the frame exchange period α shorter than the communication period β, the link selection unit 2342 may select any of these links.

[0098] The frame exchange period α is the communication possible period β N If the frame exchange period α is equal to the communication period β, the determination unit 2345 may determine that the frame exchange can be completed before the start of the r-TWT service period scheduled for link N. In this case, in step S1004, the determination unit 2345 determines whether there is a link for which the frame exchange period α is equal to or less than the communication period β.

[0099] As described above, the terminal 20 establishes multiple links with the access point 10 and selectively uses the multiple links to transmit data frames to the access point 10. The terminal 20 calculates a frame exchange period that includes the time period required to transmit data frames to the access point 10. When transmission rights for multiple links are acquired and r-TWT service periods are scheduled for all of these links, the terminal 20 calculates a communication available period for each of these links. If there is a link whose frame exchange period is shorter than the communication available period, the terminal 20 transmits data frames on that link, and if there is no link whose frame exchange period is shorter than the communication available period, the terminal 20 postpones the data frame transmission.

[0100] According to the above configuration, a link that can complete data frame transmission before the start of the r-TWT service period is found, and data frame transmission can be performed. In this case, a situation in which data frame transmission is postponed due to the r-TWT service period is avoided. Therefore, the frequency of the situation in which data frame transmission is postponed due to the r-TWT service period is reduced, and collisions or a decrease in frequency utilization efficiency can be effectively avoided. As a result, throughput and delay characteristics are improved.

[0101] When there are multiple links with a frame exchange period shorter than the communication period, the terminal 20 may transmit data frames over the link with the longest communication period. This configuration increases the reliability that data frame transmission will be completed before the start of the r-TWT service period.

[0102] In response to the presence of a link for which an r-TWT service period is not scheduled, the terminal 20 may transmit a data frame on the link for which an r-TWT service period is not scheduled. This configuration makes it possible to omit the process of calculating the communication available period.

[0103] The terminal 20 may calculate the communication available period for each of the multiple links for which the transmission right has been acquired by carrier sensing. This configuration reduces the cost of calculating the communication available period.

[0104] (Variation) In the above-described embodiment, the frame exchange period α is calculated for each data frame transmission. In some data frame transmissions, a statistical average or median of the frame exchange periods calculated over a certain period may be used as the frame exchange period α.

[0105] In the above-described embodiment, each time a transmission right is acquired, the communication period β N In some cases where the transmission right is acquired, the statistical average or median of the communication period for link N calculated over a certain period is used as the communication period β NIt may also be used as.

[0106] In multi-link operation, a TID may be associated with a link. Each link is used to transmit and receive traffic of the TID associated with the link. In the example shown in FIG. 2, traffic with TID #1 is transmitted using one of three links with link IDs 1 to 3, traffic with TID #2 is transmitted using the link with link ID 1, traffic with TID #3 is transmitted using the link with link ID 2, and traffic with TID #4 is transmitted using the link with link ID 3. Association of TIDs and links (TID-to-link mapping) may be performed when a multi-link is established between the access point 10 and the terminal 20.

[0107] 9, the TID of the traffic included in the data frame may be taken into consideration. Specifically, in step S1002, the carrier sense execution unit 245 may perform carrier sense on one or more links associated with the TID of the traffic included in the data frame to be transmitted. Referring to the above example, if the TID of the traffic included in the data frame to be transmitted is #1, the carrier sense execution unit 245 performs carrier sense on three links with link IDs 1 to 3. If the TID of the traffic included in the data frame to be transmitted is #2, the carrier sense execution unit 245 performs carrier sense on one link with link ID 2.

[0108] In the above-described embodiment, it is assumed that the terminal 20 is a transmitting station and the access point 10 is a receiving station. In a situation where the access point 10 is a transmitting station and the terminal 20 is a receiving station, the access point 10 may transmit data frames in the same manner as described above for the terminal 20. That is, the access point 10 may include components equivalent to the communication control unit 234 of the terminal 20.

[0109] The wireless communication functions of the wireless stations (access point 10 and terminal 20) may be implemented by discrete components such as chips. For example, a chip may be embedded in a substrate of the wireless station when the wireless station is manufactured. The wireless device referred to here may refer to a wireless station or to a discrete component that realizes the wireless communication functions of the wireless station.

[0110] The present invention is not limited to the above-described embodiments, and various modifications can be made in the implementation stage without departing from the spirit of the invention. Furthermore, the embodiments may be implemented in appropriate combinations, in which case the combined effects can be obtained. Furthermore, the above-described embodiments include various inventions, and various inventions can be extracted by combining selected components from the disclosed components. For example, if the problem can be solved and the effects can be obtained even if some components are removed from all the components shown in the embodiments, the configuration from which these components are removed can be extracted as an invention. [Explanation of symbols]

[0111] 10...Access point 11...CPU 12...Program memory 13...RAM 14...Wireless communication module 15...Wired communication module 20...Terminal 21...CPU 22...Program memory 23...RAM 24...Wireless communication module 25…Display 26…Storage 30...Server 40...Communication Network 45...Wireless network 50...Communication Systems 110...LLC Processing Section 120...Link Management Department 121...Data processing unit 122...MAC frame processing unit 123...Management Department 130…Communications Department 131, 132, 133...Radio signal processing unit 210...Application execution unit 220...LLC Processing Section 230...Link Management Department 231...Data processing unit 232...MAC frame processing unit 233...Management Department 234...Communication control unit 240…Communications Department 241, 242, 243...Radio signal processing unit 245…Career Sense Executive Department 2341…Instruction section 2342...Link selection section 2343...Frame exchange period calculation unit 2344...Communication period calculation unit 2345...Judgment section 2346...Transmission control unit 2411...Classification section 2412A, 2412B, 2412C, 2412D, 2422A, 2432A… queue 2413A, 2413B, 2413C, 2413D, 2423A, 2433A...Carrier sense execution unit 2414…Internal conflict management department 2415...Modulation section

Claims

1. A wireless device, a communication unit that wirelessly communicates with the other wireless devices using a plurality of links established between the wireless device and the other wireless devices; a first calculation unit that calculates a frame exchange period including a time period required to transmit a frame to the other wireless device; a second calculation unit that calculates, for each of the plurality of links, a communication available period indicating a time period until a start of a service period during which a transmission opportunity is provided for traffic requiring a delay, the time period being an available period for the frame transmission for which the frame exchange period has been calculated; and a transmission control unit that, when there is a link whose frame exchange period is shorter than the communication available period, transmits the frame over the link whose frame exchange period is shorter than the communication available period, and postpones the frame transmission when there is no link whose frame exchange period is shorter than the communication available period; A wireless device comprising:

2. when there are a plurality of links whose frame exchange period is shorter than the communication available period, the transmission control unit transmits the frame through the link whose communication available period is the longest.

10. The wireless device of claim 1.

3. the second calculation unit checks whether the service period is scheduled for each of the plurality of links; the transmission control unit, in response to the presence of a link for which the service period is not scheduled, transmits the frame on the link for which the service period is not scheduled; 10. The wireless device of claim 1.

4. a carrier sense execution unit that performs carrier sense on the plurality of links; the second calculation unit calculates the communication available period for each of a plurality of links for which the transmission right has been acquired by the carrier sense; 10. The wireless device of claim 1.

5. 1. A wireless communication method performed by a wireless device, comprising: wirelessly communicating with the other wireless devices using a plurality of links established between the wireless device and the other wireless devices; calculating a frame exchange period including a time period required for transmitting a frame to the other wireless device; calculating, for each of the plurality of links, a communication available period indicating a time period until the start of a service period during which a transmission opportunity is provided for traffic with a delay requirement, the time period being an available period for transmitting the frame for which the frame exchange period has been calculated, the service period being set for the wireless device or for a wireless device different from both the wireless device and the other wireless device; When there is a link whose frame exchange period is shorter than the communication available period, transmitting the frame on the link whose frame exchange period is shorter than the communication available period, and when there is no link whose frame exchange period is shorter than the communication available period, postponing the frame transmission; A wireless communication method comprising:

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