Wireless device and wireless communication method

Abstract

A wireless device according to an aspect of the present invention comprises a first calculation unit, a second calculation unit, and a transmission control unit. A communication unit performs wireless communications with other wireless devices by using a plurality of links established between the wireless device and other wireless devices. The first calculation unit calculates a frame exchange period including a time period required for transmitting a frame to other wireless devices. The second calculation unit calculates a communicable period indicating a time period to the start of a service period during which an opportunity of transmission is offered, and calculates a communicable period for a first link when the service period is scheduled for the first link. If the frame exchange period is shorter than the communicable period for the first link, the transmission control unit performs frame transmission with the first link. If the frame exchange period is longer than the communicable period for the first link, the transmission control unit tries frame transmission with a second link that is included in a plurality of links and is different from the first link.

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 a communication period indicating a time period until a service period in which a transmission opportunity is provided begins, and calculates the communication period for the first link when the service period is scheduled for the first link. The transmission control unit transmits the frame via the first link when the frame exchange period is shorter than the communication period for the first link, and attempts to transmit the frame via a second link included in the multiple links and different from the first link when the frame exchange period is longer than the communication period for the first link. [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 transmission process in the terminal according to the embodiment. [Figure 7] FIG. 7 is a diagram illustrating a situation in which the frame exchange period is shorter than the communication enabled period according to the embodiment. [Figure 8] FIG. 8 is a diagram illustrating a situation in which the frame exchange period is longer than the communication enabled period according to the embodiment. [Figure 9] FIG. 9 is a flowchart showing a wireless communication method according to the embodiment. [Figure 10] FIG. 10 is a block diagram showing a functional configuration of a terminal according to another example of 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 a link set (LS). The access point and terminal further support r-TWT operation. The access point schedules an r-TWT service period 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, a terminal wirelessly transmits a data frame to an access point, for example, in the following procedure. First, the terminal attempts to transmit a data frame using a first link included in a link set. Specifically, the terminal performs carrier sensing on the first link to check the status of a channel corresponding to the first link. The terminal determines that a channel is idle when the channel 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. When the terminal confirms that the channel is idle, it recognizes that it has acquired the transmission right for the first link. When the terminal acquires the transmission right for the first link, it checks whether an r-TWT service period is scheduled for the first link. If an r-TWT service period is not scheduled for the first link, the terminal transmits the data frame on the first link. If an r-TWT service period is scheduled for the first link, the terminal checks whether the data frame transmission can be completed by the start of the r-TWT service period. If the data frame transmission can be completed, the terminal transmits the data frame on the first link. If completion is not possible, the terminal attempts to transmit the data frame using a second link included in the link set. Specifically, the terminal performs carrier sensing on the second link. After acquiring the transmission right for the second link, the terminal checks whether an r-TWT service period is scheduled for the second link. If an r-TWT service period is not scheduled for the second link, the terminal transmits the data frame on the second link. If an r-TWT service period is scheduled for the second link, the terminal checks whether the data frame transmission will be completed by the start of the r-TWT service period. If completion is possible, the terminal transmits the data frame on the second link. If completion is not possible, the terminal may attempt to transmit the data frame using a third link included in the link set, or may postpone the data frame transmission.

[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 an 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 (AP) 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 terminal 20 may be a terminal that follows multi-link operation in which multiple links are established, or may be a terminal that operates in a mode also known as EMLSR (enhanced multi-link single radio) mode. A terminal that follows multi-link operation in which multiple links are established can simultaneously transmit and receive frames via multiple links. A terminal operating in EMLSR mode supports operation via multiple links, but can only transmit frames via one link at a time. A terminal 20 operating in EMLSR mode notifies the access point 10 that it operates in EMLSR mode and notifies the access point 10 of a set of links that can be used between the access point 10 and the terminal 20. Note that the terminal 20 can receive management frames (described later) in parallel via multiple links included in the link set LS, but may be configured to receive data frames via only one of the multiple links.

[0026] An example in which the terminal 20 operates in EMLSR mode will be described below. The terminal 20 switches the link used for frame exchange among available links. The terminal 20 can listen to multiple links. When frame exchange is initiated by the access point 10, the access point 10 may select one link from the available links and transmit a control frame to the terminal 20 to notify the start of frame exchange on the selected link. When the terminal 20 receives the control frame from the access point 10, it may decide to use the link on which the control frame was received and transmit a response to the control frame to the access point 10 on that link. Thereafter, the access point 10 and the terminal 20 perform frame exchange on that link. When frame exchange is initiated by the terminal 20, the terminal 20 may start frame exchange without transmitting a control frame such as that described above to the terminal 20.

[0027] The IEEE 802.11 standard defines Layer 1 and Layer 2 (MAC) sublayer of the OSI (Open Systems Interconnection) 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, an LLC (logical link control) layer and a MAC layer. The LLC layer forms LLC packets by adding, for example, a DSAP (destination service access point) header and an SSAP (source service access point) header to data input from a higher layer. The MAC layer generates MAC frames by adding, for example, a MAC header to LLC packets. The physical layer generates wireless frames by adding, for example, a preamble and a PHY (physical layer) 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.

[0028] 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, link set information, and traffic information.

[0029] 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. All three links use channels in the 5 GHz band, and the link with link ID 1 is using channel CH1 included in the 5 GHz band, the link with link ID 2 is using channel CH2 included in the 5 GHz band, and the link with link ID 3 is using channel CH3 included in the 5 GHz band. Note that different frequency bands may be assigned to the multiple links in link set LS, or different channels in the same frequency band may be assigned to the multiple links.

[0030] The link information indicates whether a link has been established between the access point 10 and the terminal 20. The link set information indicates whether a link set LS consisting of multiple links has been established between the access point 10 and the terminal 20. If a link set LS has been established, the link set information indicates which links make up the link set LS. In the example shown in FIG. 2, the link set LS is made up of three links with link IDs 1 to 3.

[0031] 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. Access categories include, for example, VO (Voice), VI (Video), BE (Best Effort), and BK (Background). In the example shown in FIG. 2, TID#1 corresponds to any of VO, VI, BE, and BK. TID#1 is assigned to each of the link with link ID 1, the link with link ID 2, and the link with link ID 3.

[0032] 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.

[0033] 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.

[0034] 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, and is connected to an antenna. The wireless communication module 14 includes multiple communication modules each corresponding to a multiple frequency band. 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.

[0035] 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.

[0036] 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 and is connected to an antenna. The wireless communication module 24 is configured to selectively perform multiple processes corresponding to multiple channels. Specifically, the wireless communication module 24 is configured to perform a process corresponding to a channel corresponding to one link adaptively selected from 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, the display 25 may be provided with a touch panel. The storage 26 is a non-volatile storage device and stores data including, for example, system software for the terminal 20.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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 .

[0043] 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.

[0044] 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 link set with the terminal via the communication unit 130. Specifically, in response to receiving a connection request from the terminal 20, the management unit 123 performs an association process and a subsequent authentication process to establish multiple links between the access point 10 and the terminal 20. Data exchange between the access point 10 and the terminal 20 is performed using any one of the links included in the link set. Data exchange between the access point 10 and a terminal following a multi-link operation in which multiple links are established is performed using any one or more of the links included in the link set. 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.

[0045] 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 the 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 period for each r-TWT service period.

[0046] 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.

[0047] 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 5 GHz band channel, a radio signal processing unit 132 configured to transmit and receive radio signals using a 5 GHz band channel, and a radio signal processing unit 133 configured to transmit and receive radio signals using a 5 GHz band channel. Note that these channels are in the same frequency band but different channels. 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 a predetermined demodulation process on the received radio signals to obtain radio frames. The predetermined demodulation process includes, for example, frequency conversion, OFDM demodulation, fast Fourier transform (FFT), subcarrier demodulation, deinterleaving, and Viterbi decoding. Then, the radio signal processing unit 131 extracts the MAC frame from the radio frame and sends the MAC frame 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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 link set 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.

[0054] 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.

[0055] The communication control unit 234 controls the operation of the communication unit 240. For example, the communication control unit 234 adaptively switches the link 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.

[0056] 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 and an antenna selection unit 242. The radio signal processing unit 241 wirelessly transmits a MAC frame. For example, the radio signal processing unit 241 generates a radio frame by adding a preamble, a PHY (physical layer) header, etc. to the MAC frame, converts the radio frame into a radio signal by performing modulation processing according to a link (channel) specified by the communication control unit 234, 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 antenna selection unit 242 selects an antenna according to the link (channel) specified by the communication control unit 234.

[0057] The process for transmitting data frames on the uplink will now be briefly described.

[0058] 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.

[0059] The data processing unit 231 receives an LLC packet from the LLC processing unit 220, generates a MAC frame from the LLC packet, and sends the MAC frame to the MAC frame processing unit 232. The MAC frame processing unit 232 receives the MAC frame from the data processing unit 231 and sends the MAC frame to the radio signal processing unit 241.

[0060] The radio signal processing unit 241 receives a MAC frame from the MAC frame processing unit 232 and temporarily stores the MAC frame. The radio signal processing unit 241 wirelessly transmits the MAC frame in accordance with an instruction from the communication control unit 234. For example, 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 according to a link (channel) specified by the communication control unit 234, and emits the radio signal via an antenna according to the link (channel) specified by the communication control unit 234.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] Data frame transmission in the terminal 20 will be described in detail with reference to Fig. 6. Fig. 6 shows an example of the functional configuration of the communication control unit 234 and the radio signal processing unit 241.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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 for a link specified by the communication control unit 234 in accordance with a preset access parameter set. 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.

[0070] When the carrier sense execution unit 2413A acquires the transmission right, it notifies the communication control unit 234 that it has acquired the transmission right. 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 one of a transmission start signal that instructs the start of transmission, a link designation signal that designates a link, or a transmission postponement signal that instructs the postponement of transmission. When the carrier sense execution unit 2413A receives a transmission instruction signal from the communication control unit 234, it retrieves a data frame from the queue 2412A and sends the data frame to the internal collision management unit 2414. When the carrier sense execution unit 2413A receives a link designation signal from the communication control unit 234, it performs carrier sensing on the link indicated by the link designation signal. Then, when the carrier sense execution unit 2413A acquires the transmission right, it notifies the communication control unit 234 that it has acquired the transmission right. When the carrier sense execution unit 2413A receives a transmission postponement signal from the communication control unit 234, it postpones transmission. For example, the carrier sense execution unit 2413A waits until it receives a link designation signal from the communication control unit 234.

[0071] 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.

[0072] The modulation unit 2415 receives the data frame from the internal collision management unit 2414 and performs modulation processing on the data frame in accordance with the channel corresponding to the link for which the transmission right has been acquired.

[0073] The communication control unit 234 includes a link selection unit 2341, an instruction unit 2342, a frame exchange period calculation unit 2343, a communication possible period calculation unit 2344, and a determination unit 2345. The communication control unit 234 performs similar processing for each of the carrier sense execution units 2413A, 2413B, 2413C, and 2413D. Here, the exchange between the communication control unit 234 and the carrier sense execution unit 2413A will be described.

[0074] The link selection unit 2341 selects one link from among the links established with the access point 10, and notifies the instruction unit 2342 of the selected link. To select a link, the link selection unit 2341 refers to link management information held by the management unit 233. The link selection unit 2341 identifies a link established with the access point 10 based on the link management information. When the link management information is the link management information shown in FIG. 2, three links 1 to 3 are established between the access point 10 and the terminal 20. Here, link N refers to the link whose link ID is N.

[0075] Instruction unit 2342 exchanges information with carrier sense execution unit 2413A. Instruction unit 2342 issues instructions to carrier sense execution unit 2413A. For example, when instruction unit 2342 receives a notification from link selection unit 2341, it sends a link designation signal indicating the link selected by link selection unit 2341 to carrier sense execution unit 2413A.

[0076] 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. 7 . The processing related to transmitting a data frame to the access point 10 may indicate a process of transmitting a data frame to the access point 10, or may indicate a series of processes of 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.

[0077] 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 2342, 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.

[0078] The communication period calculation unit 2344 calculates a communication period indicating the time period until the start of the r-TWT service period for the link selected by the link selection unit 2341. The communication 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. 7. The communication period calculation unit 2344 checks whether an r-TWT service period has been scheduled for the link selected by the link selection unit 2341. 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.

[0079] If an r-TWT service period is scheduled, the communication period calculation unit 2344 calculates the communication period. If an r-TWT service period is not scheduled, the communication period calculation unit 2344 notifies the instruction unit 2342 that an r-TWT service period is not scheduled. Alternatively, the communication period calculation unit 2344 may set the communication period to a value indicating a sufficiently long period.

[0080] When the instruction unit 2342 receives a notification from the communication available period calculation unit 2344 indicating that the r-TWT service period has not been scheduled, the instruction unit 2342 sends a transmission start signal to the carrier sense execution unit 2413A.

[0081] The determination unit 2345 determines whether frame exchange including data frame transmission 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 available period calculated by the communication available period calculation unit 2344. If the frame exchange period is equal to or shorter than the communication available period as shown in Fig. 7, the determination unit 2345 determines that the frame exchange will be completed by the start of the r-TWT service period, and if the frame exchange period is longer than the communication available period as shown in Fig. 8, the determination unit 2345 determines that the frame exchange will not be completed by the start of the r-TWT service period. The determination unit 2345 notifies the instruction unit 2342 of the determination result.

[0082] The instruction unit 2342 receives the determination result from the determination unit 2345. If the determination result indicates that the data frame transmission will be completed by the start of the r-TWT service period, the instruction unit 2342 sends a transmission start signal to the carrier sense execution unit 2413A. If the determination result indicates that the data frame transmission will not be completed by the start of the r-TWT service period, the instruction unit 2342 instructs the link selection unit 2341 to select a link. Upon receiving the instruction from the link selection unit 2341, the link selection unit 2341 selects another link and notifies the instruction unit 2342 of the selected link. Upon receiving the notification from the link selection unit 2341, the instruction unit 2342 sends a link designation signal to the carrier sense execution unit 2413A. If there is no selectable link, the link selection unit 2341 notifies the instruction unit 2342 that there is no selectable link. Upon receiving the notification from the link selector 2341, the instructor 2342 sends a transmission postponement signal to the carrier sense executor 2413A.

[0083] The link selection unit 2341, the instruction unit 2342, and the determination unit 2345 may be collectively referred to as a transmission control unit 2346. The transmission control unit 2346 is configured to perform data frame transmission on a first link (e.g., link 1) via the communication unit 240 when the frame exchange period is equal to or shorter than the communication period for the first link, and to attempt data frame transmission on a second link (e.g., link 2) when the frame exchange period is longer than the communication period for the first link. Attempting data frame transmission on the second link may include checking whether an r-TWT service period is scheduled for the second link, and instructing the communication period calculation unit 2344 to calculate the communication period for the second link when the r-TWT service period is scheduled for the second link. Attempting to transmit the data frame on the second link may include transmitting the data frame on the second link when the transmission right for the second link is acquired and an r-TWT service period is not scheduled for the second link, and transmitting the data frame on the second link via the communication unit 240 when the transmission right for the second link is acquired and the frame exchange period is equal to or less than the communication period for the second link. The transmission control unit 2346 may be further configured to attempt transmitting the data frame on a third link or may be further configured to postpone transmitting the data frame when the frame exchange period is longer than the communication period for the second link.

[0084] Fig. 9 shows a schematic diagram of a wireless communication method according to an embodiment. Specifically, Fig. 9 shows a schematic diagram of an example of a method in which the terminal 20 wirelessly transmits a data frame to the access point 10. The process shown in Fig. 9 is performed individually for each access category. Here, the process for the access category VO will be described. Let N be the number of links established between the access point 10 and the terminal 20. max Let's say.

[0085] 9, 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.

[0086] After the process shown in step S901 is executed, the link selection unit 2341 sets the variable N to 1 and selects link 1 (the link whose link ID is 1). The instruction unit 2342 sends a link designation signal indicating the selected link 1 to the carrier sense execution unit 2413A.

[0087] In step S902, the carrier sense execution unit 2413A performs carrier sense for link N and acquires the transmission right for link N.

[0088] In step S903, the communication available period calculation unit 2344 checks whether an r-TWT service period has been scheduled for link N.

[0089] If an r-TWT service period has not been scheduled for link N (step S903; No), the process proceeds to step S909. In step S909, the transmission control unit 2346 transmits a data frame to the access point 10 over link N via the communication unit 240. For example, the instruction unit 2342 sends a transmission start signal to the carrier sense execution unit 2413A, and in response to receiving the transmission start signal from the instruction unit 2342, 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. The modulation unit 2415 performs modulation processing on the data frame according to link N to generate a radio signal, and transmits the radio signal via an antenna.

[0090] If an r-TWT service period is scheduled for link N (step S903; Yes), the process proceeds to step S904. In step S904, the communication period calculation unit 2344 calculates the communication period β for link N. N Calculate the communication period β for link N. N may indicate the time interval from the reference time to the time when the r-TWT service period starts. 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 S905, the determination unit 2345 determines whether the frame exchange period α is equal to or shorter than the communication available period β for the link N. N Determine whether it is longer than

[0092] The frame exchange period α is the communication period β for link N. N If the time is not longer than (step S905; No), the process proceeds to step S909. In step S909, the communication unit 240 transmits the data frame to the access point 10 via link N.

[0093] The frame exchange period α is the communication period β for link N. N If the variable N is longer than the number of links N (step S905; Yes), the process proceeds to step S906. max Determine whether it is equal to

[0094] Variable N is the number of links N maxIf it is not equal to (step S906; No), the process proceeds to step S907. In step S907, the link selection unit 2341 determines to change the link to be used for data frame transmission. For example, the link selection unit 2341 increments the variable N by 1 and selects link N. The instruction unit 2342 sends a link designation signal indicating link N to the carrier sense execution unit 2413A. The process returns to step S902.

[0095] Variable N is the number of links N max (step S906; Yes), the process proceeds to step S908. In step S908, the transmission control unit 2346 postpones the data frame transmission. For example, the link selection unit 2341 notifies the instruction unit 2342 that there is no selectable link, and the instruction unit 2342 sends a transmission postponement signal to the carrier sense execution unit 2413A.

[0096] 9 is merely an example. For example, the process shown in step S901 may be executed after it is determined that an r-TWT service period is scheduled for link 1. The frame exchange period α is equal to or longer than the communication available period β for link N. N If so, processing may proceed from step S905 to step S906.

[0097] As described above, the terminal 20 establishes links 1 to 3 with the access point 10 and transmits data frames to the access point 10 using links 1 to 3 selectively. The terminal 20 calculates a frame exchange period including the time period required to transmit data frames to the access point 10. When the transmission right for link 1 is acquired and an r-TWT service period is scheduled for link 1, the terminal 20 calculates the communication period for link 1. The communication period for link 1 indicates the time period until the start of the r-TWT service period scheduled for link 1. When the frame exchange period is equal to or shorter than the communication period for link 1, the terminal 20 transmits data frames via link 1, and when the frame exchange period is longer than the communication period for link 1, the terminal 20 attempts to transmit data frames via link 2. For example, when attempting to transmit data frames via link 2, the terminal 20 performs carrier sense for link 2 and acquires the transmission right for link 2. When a service period is scheduled for link 2, the terminal 20 calculates the communication period for link 2. Terminal 20 transmits data frames over the second link when the frame exchange period is equal to or shorter than the communication period for link 2. Terminal 20 also transmits data frames over link 2 when no service period is scheduled for link 2.

[0098] According to the above configuration, if data frame transmission cannot be completed on link 1 by the start of the r-TWT service period, data frame transmission can be performed on link 2. When data frame transmission is performed on link 2, a situation in which data frame transmission is postponed due to the r-TWT service period is avoided. This reduces the frequency of situations in which data frame transmission is postponed due to the r-TWT service period, and effectively prevents collisions or a decrease in frequency utilization efficiency. As a result, throughput and delay characteristics are improved. Furthermore, even when terminal 20 cannot simultaneously transmit and receive frames on multiple links, an appropriate link can be selected.

[0099] Terminal 20 may attempt to transmit a data frame on link 3 if the frame exchange period is longer than the communication available period for link 2. By attempting data frame transmission on a larger number of links, the frequency of postponement of data frame transmission due to the r-TWT service period is reduced, and collisions or reductions in spectral efficiency can be more effectively avoided, resulting in further improvements in throughput and delay characteristics.

[0100] In response to the fact that an r-TWT service period is not scheduled for link 2, terminal 20 may transmit a data frame on link 2. This configuration can omit the calculation and determination process of the communication available period, thereby reducing processing costs.

[0101] (Variation) In the above-described embodiment, the link selector 2341 selects links in the order of their link IDs. Link selection may also be performed according to other criteria. In one example, the link selector 2341 may select links in the order of the least number of times an r-TWT service period has been set. In this case, the management unit 233 increments the count for each link each time an r-TWT service period is set. Links in which an r-TWT service period has been set less frequently are less likely to have an r-TWT service period scheduled, and therefore are more likely to be able to transmit data frames. For this reason, it is expected that the process shown in FIG. 9 will reach a conclusion to transmit data frames at an earlier stage. In other words, it is expected that resources required for the process can be reduced. In another example, the link selector 2341 may select links in the order of the most number of times it has been determined that the frame exchange period is equal to or shorter than the communication-enabled period. In this case, it is expected that the process shown in FIG. 9 will reach a conclusion to transmit data frames at an earlier stage, and it is expected that resources required for the process can be reduced.

[0102] 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.

[0103] 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 N It may also be used as.

[0104] 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. For example, TID#1 is associated with links 1 to 3, TID#2 is associated with link 1, TID#3 is associated with link 2, and TID#4 is associated with link 3. In this case, traffic with TID#1 is transmitted using one of links 1 to 3, traffic with TID#2 is transmitted using link 1, traffic with TID#3 is transmitted using link 2, and traffic with TID#4 is transmitted using link 3. The association of TIDs with links (TID-to-link mapping) may be performed when a link set is established between the access point 10 and the terminal 20.

[0105] 9, the TID of the traffic included in the data frame may be taken into consideration. Specifically, a series of processes shown in steps S902 to S905 may be performed for the link associated with the TID of the traffic. For example, a step of determining whether link N is associated with the TID of the traffic included in the data frame may be provided between steps S901 and S902. If link N is associated with the TID of the traffic, the process proceeds to step S902, and if link N is not associated with the TID of the traffic, the process proceeds to step S906.

[0106] In the above-described embodiment, the terminal 20 is a terminal operating in EMLSR mode. The terminal 20 may be a terminal following a multi-link operation in which multiple links are established.

[0107] Fig. 10 shows an example of the functional configuration of a terminal 20 that follows a multi-link operation in which multiple links are established according to an embodiment. In Fig. 10, elements that are the same as those shown in Fig. 5 are given the same reference numerals, and redundant explanations will be omitted.

[0108] As shown in FIG. 10 , 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 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. The communication unit 240 includes a radio signal processing unit 243 configured to transmit and receive radio signals using a 6 GHz channel, a radio signal processing unit 244 configured to transmit and receive radio signals using a 5 GHz channel, and a radio signal processing unit 245 configured to transmit and receive radio signals using a 2.4 GHz channel. In this case, the access point 10 also includes a radio signal processing unit configured to transmit and receive radio signals using a 6 GHz channel, a radio signal processing unit configured to transmit and receive radio signals using a 5 GHz channel, and a radio signal processing unit configured to transmit and receive radio signals using a 2.4 GHz channel. The radio signal processing units 243, 244, and 245 are associated with links 1, 2, and 3, respectively. The communication unit 240 communicates with the access point 10 using one or more radio signal processing units associated with one or more links selected by the communication control unit 234 .

[0109] 10, the classification unit 2411, queues 2412A, 2412B, 2412C, and 2412D, carrier sense execution units 2413A, 2413B, 2413C, and 2413D, internal collision management unit 2414, and modulation unit 2415 shown in FIG. 6 are provided in each of the radio signal processing units 243, 244, and 245. Note that the classification unit 2411, queues 2412A, 2412B, 2412C, and 2412D, carrier sense execution units 2413A, 2413B, 2413C, and 2413D, internal collision management unit 2414, and modulation unit 2415 may be provided in the MAC frame processing unit 232. Alternatively, the classification unit 2411 and queues 2412A, 2412B, 2412C, and 2412D may be provided in the MAC frame processing unit 232, and the carrier sense execution units 2413A, 2413B, 2413C, and 2413D and the internal collision management unit 2414 may be provided in each of the radio signal processing units 243, 244, and 245.

[0110] In the terminal 20 shown in Fig. 10, the communication control unit 234 can operate in the same manner as that described with reference to Fig. 6 and Fig. 9. Therefore, a specific description of the operation of the communication control unit 234 will be omitted.

[0111] 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.

[0112] 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.

[0113] 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]

[0114] 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...Radio signal processing unit 242...Antenna selection unit 243, 244, 245...Radio signal processing unit 2341...Link selection section 2342…Instruction 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... Queue 2413A, 2413B, 2413C, 2413D...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 a communication available period indicating a time period available for the frame transmission for which the frame exchange period has been calculated, the communication available period being a time period until the start of a service period during which a transmission opportunity is provided for traffic requiring a delay, the second calculation unit calculating the communication available period for the first link when the service period set for the wireless device or for a wireless device different from the wireless device and the other wireless device is scheduled for a first link; a transmission control unit that transmits the frame through the first link when the frame exchange period is shorter than the communication available period for the first link, and attempts to transmit the frame through a second link that is included in the plurality of links and is different from the first link when the frame exchange period is longer than the communication available period for the first link; A wireless device comprising:

2. Attempting the frame transmission on the second link includes verifying whether the service period is scheduled for the second link; the second calculation unit calculates the communication available period for the second link when the service period is scheduled for the second link; the transmission control unit transmits the frame through the second link when the frame exchange period is shorter than the communication available period for the second link.

10. The wireless device of claim 1.

3. the transmission control unit attempts to transmit the frame through a third link included in the plurality of links and different from the first link and the second link when the frame exchange period is longer than the communication available period for the second link; 3. The wireless device of claim 2.

4. the transmission control unit transmits the frame on the second link in response to the service period not being scheduled for the second link; 3. The wireless device of claim 2.

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 a communication available period indicating a time period available for the frame transmission for which the frame exchange period has been calculated, the communication available period being a time period until the start of a service period during which a transmission opportunity is provided for traffic with a delay requirement, wherein the communication available period is calculated for the first link when the service period set for the wireless device or for a wireless device different from the wireless device and the other wireless device is scheduled for the first link; transmitting the frame through the first link when the frame exchange period is shorter than the communication available period for the first link, and attempting to transmit the frame through a second link included in the plurality of links and different from the first link when the frame exchange period is longer than the communication available period for the first link; A wireless communication method comprising:

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