Base stations and wireless terminal equipment

Abstract

The present invention provides a base station and terminal equipment that suppresses the delay of data transmitted via uplink. [Solution] In an information communication system, the base station AP includes a first radio signal processing unit, a second radio signal processing unit, and a link management unit. The link management unit establishes a multilink with a wireless terminal device using the first and second radio signal processing units. The link management unit generates a trigger frame to cause the wireless terminal device to transmit uplink data and causes the first and second radio signal processing units to transmit the trigger frame to each.

Description

Technical Field

[0001] Embodiments relate to a base station and a wireless terminal device.

Background Art

[0002] As an information communication system that wirelessly connects between a base station and a wireless terminal device, a wireless LAN (Local Area Network) is known.

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The problem is to suppress the delay of data transmitted in the uplink.

Means for Solving the Problems

[0005] The base station of the embodiment includes a first radio signal processing unit, a second radio signal processing unit, and a link management unit. The link management unit establishes a multi-link with the wireless terminal device using the first radio signal processing unit and the second radio signal processing unit. The link management unit generates a trigger frame for causing the wireless terminal device to transmit uplink data, and transmits the trigger frame to each of the first radio signal processing unit and the second radio signal processing unit.

Effects of the Invention

[0006] The base station of the embodiment can suppress the delay of data transmitted in the uplink.

Brief Description of the Drawings

[0007] [Figure 1] Figure 1 is a conceptual diagram showing an example of the overall configuration of an information and communication system according to the embodiment. [Figure 2] Figure 2 is a conceptual diagram showing an example of a frequency band used in wireless communication in an information and communication system according to the embodiment. [Figure 3] Figure 3 is a table showing an example of the link status of a base station and wireless terminal device in the information communication system according to this embodiment. [Figure 4] Figure 4 is a block diagram showing an example of the hardware configuration of a base station included in the information and communication system according to the embodiment. [Figure 5] Figure 5 is a block diagram showing an example of the hardware configuration of a wireless terminal device included in the information communication system according to this embodiment. [Figure 6] Figure 6 is a block diagram showing an example of the functional configuration of a base station in the information and communication system according to the present invention. [Figure 7] Figure 7 is a block diagram showing an example of the functional configuration of the MAC frame processing unit of a base station equipped with the information communication system according to the embodiment. [Figure 8] Figure 8 is a block diagram showing an example of the functional configuration of a wireless terminal device included in the information and communication system according to this embodiment. [Figure 9] Figure 9 is a block diagram showing an example of the functional configuration of the MAC frame processing unit of a wireless terminal device included in the information communication system according to the embodiment. [Figure 10] Figure 10 is a flowchart showing an example of a multilink setup method in an information communication system according to the embodiment. [Figure 11] Figure 11 is a sequence diagram showing an overview of the uplink data transmission method when the TWT (Target Wake Time) function is used in the information communication system according to the embodiment. [Figure 12]Figure 12 is a conceptual diagram showing an example of the format of a trigger frame transmitted during the TWT period of an information communication system according to this embodiment. [Figure 13] Figure 13 is a sequence diagram showing an example of a beacon transmission and reception method in an information communication system according to the embodiment. [Figure 14] Figure 14 is a conceptual diagram showing an example of a beacon format including TWT settings used in an information communication system according to the embodiment. [Figure 15] Figure 15 is a sequence diagram showing an example of a method for transmitting uplink data when the TWT function of the information communication system according to the embodiment is used. [Modes for carrying out the invention]

[0008] The information communication system according to the embodiment will be described below with reference to the drawings. Each embodiment exemplifies an apparatus or method for realizing the technical idea of ​​the invention. The drawings are schematic or conceptual. In the following description, components having substantially the same function and configuration are denoted by the same reference numerals. Numbers and the like following letters that constitute a reference numeral are used to distinguish elements that are referred to by reference numerals containing the same letters and have similar configurations. When there is no need to distinguish between elements indicated by reference numerals containing the same letters, these elements are referred to by reference numerals containing only letters.

[0009] <Embodiment> The information and communication system 1 according to the embodiment will be described below.

[0010] <1> composition <1-1> Overall structure Figure 1 is a conceptual diagram showing an example of the overall configuration of an information and communication system 1 according to an embodiment. As shown in Figure 1, the information and communication system 1 includes, for example, a base station (Access Point) AP, at least one wireless terminal device (Wireless Terminal Apparatus) WTA, and a server SV.

[0011] The base station AP is a wireless LAN access point or a wireless LAN router. The base station AP is configured to be connectable to the network NW. The base station AP is configured to be wirelessly connectable to one or more wireless terminal devices WTA using one or more types of bands. Multi-link may be used for the wireless connection between the base station AP and the wireless terminal device WTA. Multi-link is a wireless connection capable of transmitting and receiving data using a plurality of links.

[0012] The wireless terminal device WTA is a wireless terminal such as a smartphone or a tablet computer. The wireless terminal device WTA is configured to be communicable with the base station AP that has established a link. The wireless terminal device WTA may be an electronic device such as a desktop computer or a laptop computer. A terminal identifier AID is added to the wireless terminal device WTA. The base station AP can identify a plurality of wireless terminal devices WTA connected wirelessly by the terminal identifier AID. In this example, the wireless terminal device WTA1 with AID=#1 and the wireless terminal device WTA2 with AID=#2 are connected to the base station AP.

[0013] The server SV is a computer configured to be connectable to the network NW. The server SV is configured to be communicable with the base station AP via the network NW. The server SV stores, for example, data of content targeted at the wireless terminal device WTA. The server SV can transmit and receive data to and from the wireless terminal device WTA via the base station AP. Wireless communication may be used for the communication between the base station AP and the server SV, or a combination of wireless communication and wired communication may be used.

[0014] The wireless communication between the base station AP and the wireless terminal device WTA conforms to the IEEE802.11 standard. The IEEE802.11 standard defines the first layer and the MAC sublayer of the second layer of the OSI (Open Systems Interconnection) reference model. In the OSI reference model, the communication function is divided into seven layers (the first layer: physical layer, the second layer: data link layer, the third layer: network layer, the fourth layer: transport layer, the fifth layer: session layer, the sixth layer: presentation layer, the seventh layer: application layer). The second layer (data link layer) includes an LLC (Logical Link Control) sublayer and a MAC (Media Access Control) sublayer. The outlines of the LLC sublayer and the MAC sublayer will be described later.

[0015] Also, the base station AP can use the TWT (Target Wake Time) function for communication with the wireless terminal device WTA. When the TWT function is used, a certain period is set between the base station AP and the wireless terminal device WTA, and the base station AP gives a transmission opportunity to the wireless terminal device WTA every certain period. The wireless terminal device WTA can suppress power consumption by setting the period other than the certain period set by the TWT function to a power-saving state. In the TWT function, the period during which the base station AP gives a transmission opportunity to the wireless terminal device WTA (hereinafter also referred to as the TWT service period) is set short, for example, when prioritizing power consumption suppression, and set long when prioritizing latency improvement. Also, the wireless terminal device WTA can improve the latency of low-latency data by preferentially transmitting data (hereinafter referred to as low-latency data) for which low latency is required during the TWT service period. The TWT function in the embodiment executes a process for further suppressing the delay of uplink data transmission from the wireless terminal device WTA to the base station AP. The detailed operation of the TWT function in the embodiment will be described later.

[0016] (Frequency bands used by the base station AP and the wireless terminal device WTA) Figure 2 is a conceptual diagram showing an example of frequency bands used in wireless communication in the information communication system 1 according to the embodiment. As shown in Figure 2, wireless communication between the base station AP and the wireless terminal device WTA uses, for example, the 2.4GHz band, the 5GHz band, and the 6GHz band. Each frequency band includes multiple channels. Figure 2 illustrates the case where each of the 2.4GHz band, the 5GHz band, and the 6GHz band includes three channels CH1, CH2, and CH3. Note that frequency bands other than the 2.4GHz band, the 5GHz band, and the 6GHz band may be used for wireless communication. Each frequency band only needs to be assigned at least one channel CH. In multilink, multiple channels CH are used. The multiple channels CH used in multilink may be in the same frequency band or in different frequency bands.

[0017] (An example of link status) Figure 3 is a table showing an example of link management information held by a base station AP in the information communication system 1 according to this embodiment. Link management information is information for managing the link status of each wireless terminal device WTA wirelessly connected to the base station AP. Figure 3 illustrates the link status for wireless terminal device WTA with AID=#1. As shown in Figure 3, the link management information includes, for example, information on “STA function”, “link”, “frequency band”, “channel ID”, “multilink”, and “TID (Traffic IDentifier)”.

[0018] The “STA function” refers to the Link ID associated with the STA function. The STA function corresponds to the radio signal processing unit provided by the base station AP and the wireless terminal device WTA, respectively. Each STA function may use one or more channels. In the following explanation, each STA function will be assumed to use one channel. A link is formed by a pair of STA functions: the STA function of the base station AP and the STA function of the wireless terminal device WTA. In this example, three STA functions (hereinafter referred to as STA1, STA2, and STA3) are assigned to the wireless communication between the wireless terminal device WTA with AID=#1 and the base station AP.

[0019] "Link" indicates whether a link has been established or not. In this example, STA1 and STA2 each have established a link (indicated as "Yes" in Figure 3), while STA3 does not have a link (indicated as "No" in Figure 3).

[0020] The “frequency band” indicates the frequency band used for the link. In this example, STA1, STA2, and STA3 are assigned the 6GHz band, 5GHz band, and 2.4GHz band, respectively.

[0021] The "Channel ID" indicates the ID of the channel used for the link. In this example, STA1 is assigned channel CH1 in the 6GHz band, and STA2 is assigned channel CH2 in the 5GHz band.

[0022] "Multilink" indicates whether or not a multilink has been established. In this example, the pair STA1 and STA2 have established a multilink (indicated by "○" in Figure 3).

[0023] "TID" indicates the traffic type assigned to the link (STA function). TID is an identifier that indicates the type of traffic (data). Traffic types include, for example, "VO (Voice)", "VI (Video)", "BE (Best Effort)", "BK (Background)", and "LL (Low Latency)". LL is traffic (low-latency data) that is set to a higher priority than other traffic and requires low latency. In Figure 3, each of TID #1 to #3 corresponds to one of VO, VI, BE, BK, or LL. In this example, TID #1 is assigned to STA and STA2, TID #2 is assigned to STA1, and TID #3 is assigned to STA2.

[0024] Thus, in a multilink, one or more STA functions may be assigned to a single TID. The association between traffic and STA functions is set, for example, so that the amount of traffic (amount of data) is equal across the multiple links that make up the multilink. However, traffic of similar types (e.g., priority / non-priority) may be grouped together on specific links that make up the multilink. For low-latency data transmission, it is preferable to use a multilink and assign multiple links to improve latency.

[0025] <1-2> Hardware Configuration The hardware configurations of the base station AP and the wireless terminal equipment WTA are described below.

[0026] (Base station AP hardware configuration) Figure 4 is a block diagram showing an example of the hardware configuration of a base station AP included in the information communication system 1 according to the embodiment. As shown in Figure 4, the base station AP includes, for example, a CPU (Central Processing Unit) 10, ROM (Read Only Memory) 11, RAM (Random Access Memory) 12, a wireless communication module 13, and a wired communication module 14.

[0027] The CPU 10 is an integrated circuit capable of executing various programs and controls the overall operation of the base station AP. The ROM 11 is a non-volatile semiconductor memory that stores programs and control data for controlling the base station AP. The RAM 12 is, for example, a volatile semiconductor memory and is used as a workspace for the CPU 10. The wireless communication module 13 is a circuit used for transmitting and receiving data via wireless signals and is configured to be connectable to an antenna. The wireless communication module 13 may also include multiple communication modules corresponding to multiple frequency bands. The wired communication module 14 is a circuit used for transmitting and receiving data via wired signals and is configured to be connectable to a network NW. Note that the base station AP may have other hardware configurations. For example, if the base station AP is wirelessly connected to a network NW, the wired communication module 14 may be omitted from the base station AP.

[0028] (Hardware configuration of the wireless terminal device WTA) Figure 5 is a block diagram showing an example of the hardware configuration of a wireless terminal device WTA included in the information communication system 1 according to this embodiment. As shown in Figure 5, the wireless terminal device WTA includes, for example, a CPU 20, ROM 21, RAM 22, a wireless communication module 23, a display 24, and storage 25.

[0029] The CPU 20 is an integrated circuit capable of executing various programs and controls the overall operation of the wireless terminal device WTA. The ROM 21 is a non-volatile semiconductor memory that stores programs and control data for controlling the wireless terminal device WTA. The RAM 22 is, for example, a volatile semiconductor memory and is used as a workspace for the CPU 20. The wireless communication module 23 is a circuit used for sending and receiving data via wireless signals and is configured to be connectable to an antenna. The wireless communication module 23 may also include, for example, multiple communication modules corresponding to multiple frequency bands. The display 24 displays, for example, a GUI (Graphical User Interface) corresponding to application software. The display 24 may also function as an input interface for the wireless terminal device WTA. The storage 25 is a non-volatile storage device that stores, for example, the system software of the wireless terminal device WTA. The wireless terminal device WTA may have other hardware configurations. For example, if the wireless terminal device WTA is an IoT (Internet of Things) terminal, the display 24 may be omitted from the wireless terminal device WTA.

[0030] <1-3> Functional Configuration The following describes the functional configurations of the base station AP and the wireless terminal equipment WTA.

[0031] (Functional configuration of base station APs) Figure 6 is a block diagram showing an example of the functional configuration of a base station AP provided by the information communication system 1 according to the embodiment. As shown in Figure 6, the base station AP includes, for example, an LLC processing unit 110, a data processing unit 120, a management unit 130, a MAC frame processing unit 140, and wireless signal processing units 150, 160, and 170. The LLC processing unit 110 can be implemented, for example, by a combination of a CPU 10, RAM 12, and a wired communication module 14. The processing of the data processing unit 120, the management unit 130, the MAC frame processing unit 140, and the wireless signal processing units 150, 160, and 170 can each be implemented, for example, by a combination of a CPU 10, RAM 12, and a wireless communication module 13.

[0032] The LLC processing unit 110 performs, for example, processing of the LLC sublayer of Layer 2 and processing of Layers 3 through 7 on the input data. The data processing unit 120, management unit 130, and MAC frame processing unit 140 perform processing of the MAC sublayer of Layer 2 on the input data. The radio signal processing units 150, 160, and 170 perform processing of Layer 1 on the input data. Hereinafter, the set of data processing unit 120, management unit 130, and MAC frame processing unit 140 provided in the base station AP will also be referred to as the "base station AP link management unit MLD".

[0033] The following describes the details of the various functions provided by the base station AP.

[0034] The LLC processing unit 110 receives data from the server SV via the network NW, for example. The LLC processing unit 110 then adds DSAP (Destination Service Access Point) headers and SSAP (Source Service Access Point) headers to the received data to generate an LLC packet. The LLC processing unit 110 then inputs the generated LLC packet to the data processing unit 120. The LLC processing unit 110 also receives an LLC packet from the data processing unit 120 and extracts data from the received LLC packet. The LLC processing unit 110 then sends the extracted data to the server SV via the network NW.

[0035] The data processing unit 120 adds a MAC header to the LLC packet input from the LLC processing unit 110 to generate a MAC frame. The data processing unit 120 then inputs the generated MAC frame to the MAC frame processing unit 140. The data processing unit 120 also receives the MAC frame from the MAC frame processing unit 140 and extracts the LLC packet from the received MAC frame. The data processing unit 120 then inputs the extracted LLC packet to the LLC processing unit 110. Hereafter, the MAC frame containing data will also be referred to as a "data frame".

[0036] The management unit 130 manages the link status between the base station AP and the wireless terminal device WTA. Information regarding link control and management can be exchanged between the management unit 130 and the MAC frame processing unit 140. The management unit 130 can also instruct the MAC frame processing unit 140 to perform predetermined processing. The management unit 130 includes, for example, link management information 131, association processing unit 132, authentication processing unit 133, link control unit 134, beacon management unit 135, common time generation unit 136, and trigger generation unit 137.

[0037] Link management information 131 is a table containing information about the link between the base station AP and the wirelessly connected wireless terminal device WTA, and includes, for example, the information shown in Figure 3.

[0038] The association processing unit 132 executes the association protocol when it receives a connection request from the wireless terminal device WTA.

[0039] The authentication processing unit 133 executes the authentication protocol that follows the association. Hereafter, MAC frames containing information related to control such as association and authentication will also be referred to as "management frames."

[0040] The link control unit 134 controls the link status with the wirelessly connected wireless terminal device WTA for each AID. In addition, when establishing a multilink, the link control unit 134 can determine the correspondence between the traffic type (TID) and the STA function.

[0041] The beacon management unit 135 manages the information transmitted by the base station AP as a beacon. For example, the beacon management unit 135 generates a MAC frame containing management information and inputs the MAC frame processing unit 140. The management information includes control values ​​used in the TWT function. A beacon is a type of management frame.

[0042] The common time generation unit 136 is a clock and generates time information. This time information is used, for example, when the link control unit 134 utilizes the TWT function. The time information may also be referenced by the MAC frame processing unit 140.

[0043] The trigger generation unit 137 generates a MAC frame containing trigger information and inputs it to the MAC frame processing unit 140. The trigger information includes information that instructs the transmission of uplink data when the TWT function is used. Specifically, the trigger information includes information indicating the resources (frequency, transmission timing, and duration) to be transmitted to the wireless terminal device WTA that transmits uplink data when the TWT function is used. Hereinafter, the MAC frame containing trigger information will be referred to as the "trigger frame". Alternatively, the trigger generation unit 137 may instruct the MAC frame processing unit 140 to generate a trigger frame along with a time specification.

[0044] The MAC frame processing unit 140 receives MAC frames from the data processing unit 120 or the management unit 130 and temporarily stores (buffers) the received MAC frames. Then, the MAC frame processing unit 140 refers to the link management information 131 to identify the link associated with the TID of the data contained in the MAC frame. Next, the MAC frame processing unit 140 performs carrier sensing. Carrier sensing is the process of checking the status of the channel corresponding to the identified link. If the channel is busy, the MAC frame processing unit 140 continues carrier sensing. If the channel is idle, the MAC frame processing unit 140 inputs the MAC frame to the radio signal processing unit corresponding to that channel. The MAC frame processing unit 140 also receives MAC frames from the radio signal processing units 150, 160, and 170 and inputs the MAC frame to the data processing unit 120 or the management unit 130 according to the type of MAC frame. Specifically, the MAC frame processing unit 140 inputs the MAC frame to the data processing unit 120 if the MAC frame is a data frame, and inputs the MAC frame to the management unit 130 if the MAC frame is a management frame.

[0045] The wireless signal processing unit 150 generates a wireless frame by adding a preamble, a PHY (physical layer) header, etc., to the data input from the MAC frame processing unit 140. Then, the wireless signal processing unit 150 converts the wireless frame into a wireless signal by performing a predetermined modulation operation on the wireless frame and radiates (transmits) the wireless signal through the antenna. The predetermined modulation operation includes, for example, convolution coding, interleaving, subcarrier modulation, inverse fast Fourier transform (IFFT), OFDM (orthogonal frequency division multiplexing) modulation, and frequency conversion. The wireless signal processing unit 150 also receives a wireless signal from the wireless terminal device WTA via the antenna and performs a predetermined demodulation operation on the received wireless signal to obtain a wireless frame. The predetermined demodulation operation includes, for example, frequency conversion, OFDM demodulation, fast fourier transform (FFT), subcarrier demodulation, deinterleaving, and Viterbi decoding. The wireless signal processing unit 150 then extracts MAC frames from wireless frames and inputs the extracted MAC frames to the MAC frame processing unit 140. The functions of the wireless signal processing units 160 and 170 are the same as those of the wireless signal processing unit 150. In this example, the wireless signal processing units 150, 160, and 170 handle wireless signals in the 6GHz, 5GHz, and 2.4GHz bands, respectively. In other words, the wireless signal processing units 150, 160, and 170 correspond to STA1, STA2, and STA3 of the base station AP, respectively. The wireless signal processing units 150, 160, and 170 may share an antenna or use separate antennas.

[0046] (Functional configuration of the MAC frame processing unit 140 of the base station AP) Figure 7 is a block diagram showing an example of the functional configuration of the MAC frame processing unit 140 of a base station AP included in the information communication system 1 according to this embodiment. Figure 7 shows details of the channel access function and uplink data reception function of the MAC frame processing unit 140.

[0047] First, the channel access function of the base station AP will be described. As shown in Figure 7, the MAC frame processing unit 140 includes, for example, a classification unit 141, transmission queues 142A, 142B, 142C, and 142D, carrier sense execution units 143A, 143B, 143C, and 143D, and a collision management unit 144, in relation to the channel access function.

[0048] The classification unit 141 classifies the MAC frame received from the data processing unit 120 into multiple access categories based on the TID contained in the MAC header. The classification unit 141 then inputs the MAC frame into one of the corresponding transmission queues 142A, 142B, 142C, and 142D. In this example, the classification unit 141 inputs the VO data into transmission queue 142A, the VI data into transmission queue 142B, the BE data into transmission queue 142C, and the BK data into transmission queue 142D. The classification unit 141 also inputs the trigger frame TF, or the instruction to generate a trigger frame TF, received from the trigger generation unit 137 to the collision management unit 144, for example, without going through transmission queue 142.

[0049] Transmit queues 142A, 142B, 142C, and 142D each buffer the incoming MAC frame. In this example, transmit queues 142A, 142B, 142C, and 142D buffer the VO, VI, BE, and BK data, respectively.

[0050] Each of the carrier sense execution units 143A, 143B, 143C, and 143D performs carrier sense based on CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance) according to the access parameters pre-configured for each carrier sense execution unit 143. The access parameters are set for each access category, for example, so that the transmission of radio signals is prioritized in the order of "VO", "VI", "BE", and "BK". The carrier sense execution units 143A, 143B, 143C, and 143D perform carrier sense on MAC frames buffered in the transmission queues 142A, 142B, 142C, and 142D, respectively. For example, if carrier sense execution unit 143A acquires transmission rights (i.e., if the channel is idle), it retrieves a MAC frame from the transmission queue 142A. The carrier sense execution unit 143A then outputs the extracted MAC frame to the radio signal processing unit (for example, one of STA1, STA2, and STA3) corresponding to the link associated with access category "VO" via the collision management unit 144.

[0051] The collision management unit 144 prevents data transmission collisions when multiple carrier sense execution units 143 acquire transmission rights for the same link. In other words, the collision management unit 144 adjusts the transmission timing of data for which transmission rights have been acquired by the same STA function, and outputs data from the access category with higher priority to the STA function. Furthermore, since carrier sense is performed on trigger frames TF without going through the transmission queue 142, they can be processed with lower latency than other traffic. In addition, the collision management unit 144 includes a part that functions as a redundancy processing unit 145 when a multilink is established and the TWT function is used.

[0052] The redundancy processing unit 145 outputs the MAC frame to be transmitted to at least two of the links when the traffic for which the right to transmit has been acquired by the collision management unit 144 is assigned to multiple links. In other words, the redundancy processing unit 145 duplicates (e.g., redundancies) the MAC frame associated with the multiple links and outputs it to two or more of the multiple links. The redundancy processing unit 145 may customize the MAC frame input to each link so that each link has unique information. Alternatively, the redundancy processing unit 145 may duplicate only the common information and input it to each link, causing each link to generate its own MAC frame. When a trigger frame TF or an instruction to generate a trigger frame TF is input to the collision management unit 144, the redundancy processing unit 145 may output to the STA function with priority over other traffic. The redundancy processing unit 145 may include beacons in the frames to be made redundant.

[0053] In this embodiment, the MAC frame processing unit 140 is shown as implementing a channel access function, but the embodiment is not limited to this. For example, the wireless signal processing units 150, 160, and 170 may implement a channel access function. In this case, the redundancy processing unit 145 is configured as part of link management. Specifically, the redundancy processing unit 145 duplicates the frame input from the MAC frame processing unit 140 and inputs it to the corresponding wireless signal processing unit. Furthermore, when transmitting a trigger frame TF, the redundancy processing unit 145 notifies each wireless signal processing unit of the time information generated by the common time generation unit 136. As a result, each wireless signal processing unit can transmit the trigger frame TF at the same time based on this time information.

[0054] Access parameters such as CWmin, CWmax, AIFS, and TXOPLimit are used. CWmin and CWmax represent the minimum and maximum values ​​of the contention window, which is the transmission waiting time for collision avoidance. AIFS (Arbitration Inter Frame Space) represents a fixed transmission waiting time set for each access category for collision avoidance control with priority control functionality. TXOPLimit represents the upper limit of TXOP (Transmission Opportunity) corresponding to the channel occupancy time. The shorter the CWmin and CWmax values, the easier it is for a transmit queue 142 to obtain transmission rights. The priority of transmit queue 142 increases as the AIFS value decreases. The amount of data transmitted in a single transmission right increases as the value of TXOPLimit increases.

[0055] Next, the uplink data reception function at the base station AP will be described. As shown in Figure 7, the MAC frame processing unit 140 includes, for example, a buffer unit 146 and a duplicate verification unit 147 in relation to the uplink data reception function.

[0056] The buffer unit 146 temporarily stores MAC frames received from each wireless signal processing unit (e.g., STA1, STA2, and STA3). When a multilink is established, the buffer unit 146 may store MAC frames containing the same information input from multiple links.

[0057] The duplicate checking unit 147 checks the MAC frames stored in the buffer unit 146 and discards all but one frame containing duplicate information. The duplicate checking unit 147 then outputs the MAC frames for which the duplicates have been resolved to the data processing unit 120 or the management unit 130, depending on the type of MAC frame. The duplicate checking unit 147 refers to, for example, the sequence number included in the MAC header to check for duplicates. For duplicate checking, it is sufficient that at least common information included in the MAC frames is used.

[0058] (Functional configuration of the wireless terminal device WTA) Figure 8 is a block diagram showing an example of the functional configuration of a wireless terminal device WTA included in the information communication system 1 according to the embodiment. As shown in Figure 8, the wireless terminal device WTA includes, for example, an application execution unit 200, an LLC processing unit 210, a data processing unit 220, a management unit 230, a MAC frame processing unit 240, and wireless signal processing units 250, 260, and 270. The processing of the application execution unit 200 and the LLC processing unit 210 can be implemented, for example, by a CPU 20 and a RAM 22. The processing of the data processing unit 220, the management unit 230, the MAC frame processing unit 240, and the wireless signal processing units 250, 260, and 270 can be implemented, for example, by a combination of a CPU 20, a RAM 22, and a wireless communication module 23.

[0059] The application execution unit 200 performs Layer 7 processing on the input data. The LLC processing unit 210 performs Layer 2 LLC sublayer processing and Layers 3 through 6 processing on the input data. The data processing unit 220, management unit 230, and MAC frame processing unit 240 perform Layer 2 MAC sublayer processing on the input data. The wireless signal processing units 250, 260, and 270 perform Layer 1 processing on the input data. Hereinafter, the set of data processing unit 220, management unit 230, and MAC frame processing unit 240 provided in the wireless terminal device WTA will also be referred to as the "Link Management Unit MLD of the wireless terminal device WTA".

[0060] The following describes the details of the various functions provided by the WTA wireless terminal device.

[0061] The application execution unit 200 executes an application that can utilize data input from the LLC processing unit 210. The application execution unit 200 also inputs data to the LLC processing unit 210 and retrieves data from the LLC processing unit 210 according to the application's operation. The application execution unit 200 can display application information on the display 24. Furthermore, the application execution unit 200 can execute processing in response to operations via the input interface.

[0062] The LLC processing unit 210 adds DSAP headers and SSAP headers to the data received from the application execution unit 200 to generate an LLC packet. The LLC processing unit 210 then inputs the generated LLC packet to the data processing unit 220. The LLC processing unit 210 also receives the LLC packet from the data processing unit 220 and extracts data from the received LLC packet. The LLC processing unit 210 then inputs the extracted data to the application execution unit 200.

[0063] The data processing unit 220 adds a MAC header to the LLC packet input from the LLC processing unit 210 to generate a MAC frame. The data processing unit 220 then inputs the generated MAC frame to the MAC frame processing unit 240. The data processing unit 220 also receives the MAC frame from the MAC frame processing unit 240 and extracts the LLC packet from the received MAC frame. The data processing unit 220 then inputs the extracted LLC packet to the LLC processing unit 210.

[0064] The management unit 230 manages the link status between the base station AP and the wireless terminal device WTA. Information regarding link control and management can be exchanged between the management unit 230 and the MAC frame processing unit 240. The management unit 230 can also instruct the MAC frame processing unit 240 to perform predetermined processing. The management unit 230 includes, for example, link management information 231, association processing unit 232, authentication processing unit 233, link control unit 234, and beacon management unit 235. Link management information 231 is a table containing information about the link with the wirelessly connected base station AP, and includes, for example, the information shown in Figure 3. The association processing unit 232 executes the association protocol when sending a connection request to the base station AP. The authentication processing unit 233 executes the authentication protocol that follows the association. The link control unit 234 controls the link status with the wirelessly connected base station AP. Furthermore, the link control unit 234 can determine the correspondence between the traffic type (TID) and the STA function when establishing a multilink. The beacon management unit 235 manages the information contained in the beacons received from the base station AP. For example, the beacon management unit 235 receives management information contained in the beacon and instructs the link control unit 234 to control the link based on the management information. The beacon management unit 235 may also notify the data processing unit 220 of the contents of the management information.

[0065] The MAC frame processing unit 240 receives MAC frames from the data processing unit 220 or the management unit 230 and temporarily stores (buffers) the received MAC frames. Then, the MAC frame processing unit 240 refers to the link management information 231 to identify the link associated with the TID of the data contained in the MAC frame. After that, the MAC frame processing unit 240 performs carrier sensing. If the channel is busy, the MAC frame processing unit 240 continues carrier sensing. If the channel is idle, the MAC frame processing unit 240 inputs the MAC frame to the radio signal processing unit corresponding to that channel. The MAC frame processing unit 240 also receives MAC frames from the radio signal processing units 250, 260, and 270 and inputs the MAC frame to the data processing unit 220 or the management unit 230 according to the type of MAC frame. For example, if the MAC frame is a data frame, the MAC frame processing unit 240 inputs the MAC frame to the data processing unit 220, and if the MAC frame is a management frame, it inputs the MAC frame to the management unit 230.

[0066] The wireless signal processing unit 250 generates a wireless frame by adding a preamble and a PHY (physical layer) header to the data input from the MAC frame processing unit 240. Then, the wireless signal processing unit 250 converts the wireless frame into a wireless signal by performing a predetermined modulation operation on the wireless frame and radiates (transmits) the wireless signal via the antenna. The wireless signal processing unit 250 also receives a wireless signal from the wireless terminal device WTA via the antenna and performs a predetermined demodulation operation on the received wireless signal to obtain a wireless frame. Then, the wireless signal processing unit 250 extracts the MAC frame from the wireless frame and inputs the extracted MAC frame to the MAC frame processing unit 240. The functions of the wireless signal processing units 260 and 270 are the same as those of the wireless signal processing unit 250. In this example, the wireless signal processing units 250, 260, and 270 handle wireless signals in the 6GHz band, 5GHz band, and 2.4GHz band, respectively. In other words, the wireless signal processing units 250, 260, and 270 correspond to STA1, STA2, and STA3 of the wireless terminal device WTA, respectively. The wireless signal processing units 250, 260, and 270 may share an antenna or use separate antennas.

[0067] (Functional configuration of the MAC frame processing unit 240 of the wireless terminal device WTA) Figure 9 is a block diagram showing an example of the functional configuration of the MAC frame processing unit 240 of the wireless terminal device WTA included in the information communication system 1 according to this embodiment. Figure 9 shows details of the channel access function and the downlink data reception function of the MAC frame processing unit 240.

[0068] First, the channel access function of the wireless terminal device WTA will be described. As shown in Figure 9, the MAC frame processing unit 240 includes, for example, a classification unit 241, transmission queues 242A, 242B, 242C, and 242D, carrier sense execution units 243A, 243B, 243C, and 243D, and a collision management unit 244 in relation to the channel access function.

[0069] The classification unit 241 classifies the MAC frame received from the data processing unit 220 into multiple access categories based on the TID contained in the MAC header. The classification unit 241 then inputs the MAC frame into one of the corresponding transmission queues 242A, 242B, 242C, and 242D. In this example, the classification unit 241 inputs VO data into transmission queue 242A, VI data into transmission queue 242B, BE data into transmission queue 242C, and BK data into transmission queue 242D. The classification unit 241 also inputs LL data (low-latency data) that requires low latency to the carrier sense execution unit 243E, for example, without going through transmission queue 242.

[0070] Transmit queues 242A, 242B, 242C, and 242D each buffer the incoming MAC frame. In this example, transmit queues 242A, 242B, 242C, and 242D buffer the VO, VI, BE, and BK data, respectively.

[0071] Each of the carrier sense execution units 243A, 243B, 243C, 243D, and 243E performs carrier sense based on CSMA / CA according to the access parameters pre-configured for each carrier sense execution unit 243. Then, each of the carrier sense execution units 243A, 243B, 243C, 243D, and 243E outputs the MAC frame for which it has acquired transmission rights to the associated link via the collision management unit 244. The access parameters are set, for example, so that the transmission of radio signals is prioritized in the order of "LL", "VO", "VI", "BE", and "BK". The carrier sense execution units 243A, 243B, 243C, and 243D perform carrier sense on MAC frames buffered in the transmission queues 242A, 242B, 242C, and 242D, respectively. The carrier sense execution unit 243E performs carrier sense on LL MAC frames received from the classification unit 241. Thus, because LL MAC frames undergo carrier sensing without going through the transmit queue 242, they can be processed with lower latency than other traffic. Note that the carrier sensing execution unit 243E may skip carrier sensing if it is a data transmission in response to the receipt of the trigger frame TF.

[0072] The collision management unit 244 prevents data transmission collisions when multiple carrier sense execution units 243 acquire transmission rights for the same link. The collision management unit 244 also includes a part that functions as a redundancy processing unit 245 when a multilink is established and the TWT function is used.

[0073] The redundancy processing unit 245 outputs the MAC frame to be transmitted to at least two of the links when the traffic for which the collision management unit 244 has acquired transmission rights is assigned to multiple links. In other words, the redundancy processing unit 245 duplicates (e.g., redundancies) the MAC frame associated with the multiple links and outputs it to two or more of the multiple links. The redundancy processing unit 245 may customize the MAC frame input to each link so that each link has unique information. Alternatively, the redundancy processing unit 245 may duplicate only the common information and input it to each link, causing each link to generate its own MAC frame. When an LL MAC frame is input to the collision management unit 244, the redundancy processing unit 245 may output it to the STA function with priority over other traffic.

[0074] In this embodiment, the MAC frame processing unit 240 is shown as implementing the channel access function, but the embodiment is not limited to this. For example, the wireless signal processing units 250, 260, and 270 may implement the channel access function.

[0075] Next, the downlink data reception function in the wireless terminal device WTA will be described. As shown in Figure 9, the MAC frame processing unit 240 includes, for example, a buffer unit 246 and a duplicate verification unit 247 in relation to the downlink data reception function.

[0076] The buffer unit 246 temporarily stores MAC frames received from each wireless signal processing unit (e.g., STA1, STA2, and STA3). When a multilink is established, the buffer unit 246 may store MAC frames containing the same information input from multiple links.

[0077] The duplicate checking unit 247 checks the MAC frames stored in the buffer unit 246 and discards all but one frame containing duplicate information. The duplicate checking unit 247 then outputs the MAC frame from which the duplicate has been resolved to the data processing unit 220 or the management unit 230, depending on the type of MAC frame. For duplicate checking, the duplicate checking unit 247 refers to, for example, the sequence number included in the MAC header. For duplicate checking, it is sufficient that at least common information included in the MAC frame is used. For example, if the duplicate checking unit 247 confirms that the buffer unit 246 has received and stored beacons containing the same information from multiple links, it resolves the duplicate and outputs the information to the beacon management unit 235. If the duplicate checking unit 247 confirms that the buffer unit 246 has received and stored trigger frames specifying the same TWT service period from multiple links, it resolves the duplicate and outputs the trigger frame to the data processing unit 220 or the management unit 230.

[0078] <2> operation <2-1> How to set up a multilink Figure 10 is a flowchart showing an example of a multilink setup method in the information communication system 1 according to the embodiment. The multilink setup method will be described below with reference to Figure 10. The multilink setup is performed between the link management unit MLD of the base station AP and the link management unit MLD of the wireless terminal device WTA, for example, using a management frame.

[0079] In process S10, the wireless terminal device WTA sends (broadcasts) a probe request to the base station AP. The probe request is a signal to check whether or not a base station AP is present in the vicinity of the wireless terminal device WTA. When the base station AP receives the probe request, it executes process S11.

[0080] In the process of S11, the base station AP sends a probe response to the radio terminal device WTA. The probe response is a signal used to respond to a probe request from the radio terminal device WTA and contains information necessary for establishing a multilink. When the radio terminal device WTA receives the probe response, it performs the process of S12.

[0081] In the processing of S12, the wireless terminal device WTA sends a multilink association request to the base station AP via one of the STA functions of the wireless terminal device WTA. The multilink association request is a signal that requests the base station AP to establish a multilink and contains information for the multilink connection. When the link management unit MLD of the base station AP receives the multilink association request, it performs the processing of S13.

[0082] In the S13 process, the base station AP's link management unit MLD performs multilink association processing. In the multilink association processing, the base station AP first performs association processing for the first STA function with the wireless terminal device WTA. Then, once a wireless connection (link) is established with the first STA function, the base station AP's link management unit MLD uses the first STA function, for which the link has been established, to perform association processing for the second STA function. Once at least two STA function association processes are completed, the base station AP recognizes that a multilink has been established with the wireless terminal device WTA and performs processing S14.

[0083] In the S14 process, the base station AP's link management unit MLD updates the link management information 131. Once the link management information 131 is updated, the base station AP executes the S15 process.

[0084] In processing S15, the base station AP sends a multilink establishment response to the wireless terminal device WTA. The multilink establishment response is a signal used to respond to a multilink request from the wireless terminal device WTA. The link management unit MLD of the wireless terminal device WTA recognizes that a multilink has been established with the base station AP based on the receipt of the multilink establishment response and executes processing S16.

[0085] In the S16 process, the link management unit MLD of the wireless terminal device WTA updates the link management information 231. As a result, the link management information is updated on both the base station AP and the wireless terminal device WTA, and the multilink setup is completed. Thereafter, the base station AP and the wireless terminal device WTA can perform data communication using the multilink.

[0086] Furthermore, the multilink setup may be performed based on beacons periodically transmitted by the base station AP. In this case, the wireless terminal device WTA performs the process in S12 based on the receipt of the beacon. That is, the processes in S10 and S11 can be omitted.

[0087] Furthermore, during multilink setup, the Link Management Unit (MLD) of both the base station AP (Application Platform) and the wireless terminal equipment (WTA) performs mapping between each link included in the multilink and the traffic type (TID). Specifically, the Link Management Unit (MLD) of the WTA determines the association between traffic and links and requests the base station AP's Link Management Unit (MLD) to apply this association. Subsequently, when the WTA receives an acknowledgment of this request from the base station AP, the association between traffic and links is finalized. For example, low-latency data (traffic) is associated with at least two of the multiple links constituting the multilink. Traffic associated with multiple links can be transmitted redundantly by the redundancy processing unit 145 or 245. Note that "traffic being transmitted redundantly" corresponds to the same traffic being transmitted on multiple links constituting the multilink.

[0088] <2-2>TWT function The details of the TWT function in the embodiment are described below.

[0089] The Link Management Unit (MLD) of a base station AP (Application Platform) or wireless terminal device (WTA) performs, for example, the setup of the TWT (Time-Waster) function to exchange low-latency data. The TWT function setup may be performed during multilink setup, or after multilink has been established, based on a request from the wireless terminal device (WTA) to transmit low-latency data. The parameters used in the TWT function (hereinafter referred to as TWT settings) are set by the respective Link Management Units (MLD) of the base station AP and the wireless terminal device (WTA). The base station AP may manage the TWT settings for each wireless terminal device (WTA) or for groups. In this embodiment, the case in which the base station AP manages the TWT settings for groups will be described. Hereinafter, a group that shares TWT settings will be referred to as a "TWT group". When the base station AP uses the TWT function, it assigns the wireless terminal device (WTA) that has established a link to the TWT group.

[0090] TWT settings are managed by the management unit 130 of the base station AP and the management unit 230 of the radio terminal equipment WTA. TWT settings include, for example, the TWT start time, TWT period, and TWT duration. The TWT start time corresponds to the start time of the TWT service period. The TWT period corresponds to the period of the TWT service period. The TWT period may also be called the TWT interval. The TWT duration corresponds to the period that gives the radio terminal equipment WTA an opportunity to transmit. During the TWT duration, multiple links that have established a multilink with the base station AP are set to a state where they can receive radio signals. When the TWT function is used, one cycle of the TWT service period can be specified by the TWT start time and the TWT duration.

[0091] The Link Management Unit (MLD) of the Wireless Terminal Equipment (WTA) waits for the transmission of low-latency data until the TWT service period begins, and then, based on the reception of a trigger frame (TF) within the TWT service period, causes each link to transmit low-latency data. Preferably, the period of the TWT service period is set to match the transmission period of low-latency data of the Wireless Terminal Equipment (WTA). The Link Management Unit (MLD) of the Base Station AP (AP) may acquire the transmission period of low-latency data to be reflected in the TWT settings by any method. For example, the Link Management Unit (MLD) of the Base Station AP may acquire the data generation period set in the application that generates low-latency data from the Wireless Terminal Equipment (WTA) and determine the TWT settings.

[0092] The TWT start time may also be expressed in terms of the TWT period. The wireless terminal device WTA can recognize the time obtained by adding the TWT period to the previous TWT start time as the next TWT start time. In other words, the wireless terminal device WTA can recognize the time obtained by adding the TWT period to the previous TWT start time as the start time of the next TWT duration.

[0093] (Overview of uplink data transmission method) Figure 11 is a sequence diagram showing an example of how to transmit uplink data when the TWT function is used in the information communication system 1 according to the embodiment. Figure 11 shows two consecutive TWT intervals TI <1> and <2> This illustrates the case where uplink data is transmitted in each of the following locations. TWT interval TI <1> and <2> Each of these has a TWT duration TD and a waiting period WP. The waiting period WP corresponds to the period during which the TWT function is in use but no transmission opportunity is provided. The following outlines the method of transmitting uplink data with reference to Figure 11.

[0094] The wireless terminal device WTA has a TWT interval TI <1> Before that, buffer the uplink data DAT1 (S20). TWT interval TI <1> When the start time of the TWT is reached, the base station AP transmits a trigger frame TF to the radio terminal device WTA within the TWT duration TD (S21). The timing of transmission of the trigger frame TF is preferably the TWT start time. In order for the trigger frame TF to be transmitted at the TWT start time, each STA function may transmit the trigger frame TF using the highest priority category of EDCA (Enhanced Distributed Channel Access), or it may transmit the trigger frame TF using a priority transmission means other than EDCA. Based on the receipt of the trigger frame TF, the radio terminal device WTA transmits uplink data DAT1 to the base station AP (S22). If the base station AP successfully receives the uplink data DAT1, it transmits an Ack to the radio terminal device WTA (S23). The radio terminal device WTA recognizes that it has successfully transmitted DAT1 after receiving the Ack after transmitting the uplink data DAT1, and discards DAT1. The processing in S21 to S23 is within the TWT interval TI <1> It is executed within the TWT duration TD.

[0095] TWT interval TI <1> When the TWT duration period TD ends, it transitions to the waiting period WP. In this example, the TWT interval TI <1> During the standby period WP, ​​the wireless terminal device WTA buffers the uplink data DAT2 (S24). TWT interval TI <2> When the start time arrives, the base station AP transmits a trigger frame TF to the radio terminal device WTA within the TWT duration TD (S25). Based on receiving the trigger frame TF, the radio terminal device WTA transmits uplink data DAT2 to the base station AP (S26). If the base station AP successfully receives the uplink data DAT2, it transmits an Ack to the radio terminal device WTA (S27). The radio terminal device WTA recognizes that it has successfully transmitted DAT2 after receiving the Ack and discards DAT2. The processing in S25-S27 is within the TWT interval TI <2> It is executed within the TWT duration TD. Then, the TWT interval TI <2> This will be a waiting period for WP.

[0096] As explained above, when the TWT function is used, the base station AP notifies the radio terminal WTA of an opportunity to transmit data using a trigger frame TF during the TWT duration TD of each TWT interval TI. The radio terminal WTA then attempts to transmit the buffered data to the base station AP each time it receives a trigger frame TF.

[0097] (Format of trigger frame TF) Figure 12 is a conceptual diagram showing an example of the format of a trigger frame transmitted during the TWT period of an information communication system according to an embodiment. As shown in Figure 12, the trigger frame includes, for example, a frame control field, a duration field, address fields (RA and TA), a common information field, a user information list field, a padding field, and an FCS (Frame Check Sequence) field.

[0098] The frame control field stores various control information. For example, the frame control field includes information indicating the frame type of the wireless frame. The duration field indicates the planned duration of use of the wireless line. The address field shows the BSSID, source address, destination address, sender terminal address, receiver terminal address, etc. The common information field includes information indicating the type of trigger frame, etc. The user information list field includes, for example, "AID" and "RU (Resource Unit) Allocation". The wireless terminal device WTA recognizes that the allocation is for its own station by the AID. The wireless terminal device WTA also recognizes the allocated resource by the RU allocation. Padding is an area that adjusts the data length of the wireless frame. The FCS field stores the error detection code of the MAC header and frame body field pair and is used to determine whether there is an error in the data frame.

[0099] (How to notify about TWT settings) A base station AP (Access Point) uses beacons, for example, as a method to notify wireless terminal devices (WTAs) of TWT settings. Beacons containing TWT settings are generated and transmitted, for example, by the base station AP's beacon management unit 135. TWT settings included in beacons received by wireless terminal devices (WTAs) are acquired and managed by the beacon management unit 235. This allows the base station AP's beacon management unit 135 to notify the wireless terminal devices (WTAs) of the TWT service period for transmitting low-latency data. The base station AP's redundancy processing unit 145 may also include beacons in the frames to be made redundant. In other words, the beacon management unit 135 can cause each link to transmit beacons announcing TWT settings, such as the TWT start time and TWT duration, for the transmission of low-latency data.

[0100] Figure 13 is a sequence diagram showing an example of a beacon transmission and reception method in the information communication system 1 according to the embodiment. Below, with reference to Figure 13, an example of a method for notifying TWT settings when a multilink is established while using the TWT function will be described.

[0101] First, the Link Management Unit (MLD) of the base station AP generates a beacon BE including the TWT setting (S30; beacon generation). Then, the Link Management Unit (MLD) of the base station AP makes the beacon BE redundant and inputs it to STA1 and STA2 of the base station AP, respectively (S31). Next, STA1 and STA2 of the base station AP each radiate (transmit) a radio signal including the beacon BE via their antennas (S32). The radio signals radiated (transmitted) by STA1 and STA2 of the base station AP are received in parallel by STA1 and STA2 of the wireless terminal device (WTA), respectively.

[0102] Next, STA1 and STA2 of the wireless terminal device WTA each input the beacon BE obtained from the received radio signal to the link management unit MLD of the wireless terminal device WTA (S33). The link management unit MLD of the wireless terminal device WTA checks for duplicate beacons input from STA1 and STA2 (S34; duplicate check). Beacons that have been found to be duplicates are eliminated and input to the beacon management unit 235 of the management unit 230. Then, the beacon management unit 235 updates the TWT settings based on the TWT settings included in the received beacons (S35; setting update).

[0103] (Beacon format) Figure 14 is a conceptual diagram showing an example of a beacon format including TWT settings used in the information communication system 1 according to the embodiment. As shown in Figure 14, a beacon may include a TWT group identifier and a TWT setting for each identifier. Specifically, a beacon sequentially stores pairs of TWT groups and TWT settings, such as "identifier for TWT group #1", "TWT setting for TWT group #1", "identifier for TWT group #2", and "TWT setting for TWT group #2". The wireless terminal device WTA can determine whether the TWT setting is for its own station based on the pair of TWT group identifier and TWT setting. Note that the beacon may be in any other format as long as the wireless terminal device WTA can determine the pair of TWT group and TWT setting.

[0104] The TWT settings for each AID included in the beacon include, for example, the TWT start time, TWT duration, and transmission suppression period. The transmission suppression period indicates the period during which the transmission of uplink data is suppressed or prohibited for the wireless terminal device WTA. The wireless terminal device WTA suppresses or prohibits the transmission of uplink data during the specified transmission suppression period. When the beacon management unit 235 of each wireless terminal device WTA receives a beacon, it obtains the TWT start time, TWT duration, and transmission suppression period and notifies each link (STA function). As a result, the base station AP can autonomously suppress the transmission of uplink data during the TWT service period in which low-latency data is transmitted for wireless terminal devices WTAs other than the wireless terminal device WTA to which low-latency data transmission is assigned.

[0105] (How to send uplink data) Figure 15 is a sequence diagram showing an example of how uplink data is transmitted when the TWT function of the information communication system 1 according to this embodiment is used. Figure 15 illustrates a case in which low-latency uplink data is transmitted redundantly during a certain TWT service period. The method of transmitting uplink data will be described below with reference to Figure 15.

[0106] The Link Management Unit (MLD) of the Wireless Terminal Equipment (WTA) buffers the uplink data DAT in, for example, the MAC frame processing unit 240 before the TWT service period begins (S40). When the TWT service period begins, the Link Management Unit (MLD) of the Base Station AP generates a trigger frame TF (S41; trigger generation). The Link Management Unit (MLD) of the Base Station AP then uses the redundancy processing unit 145 to make the trigger frame TF redundant and inputs it to STA1 and STA2 of the Base Station AP, respectively (S42). Then, STA1 and STA2 of the Base Station AP each radiate (transmit) a radio signal containing the trigger frame TF via the antenna (S43). In other words, in the processing of S41 to S43, the trigger generation unit 137 generates a trigger frame TF to cause the uplink data DAT to be sent to the Wireless Terminal Equipment (WTA), inputs it to each of the multiple links constituting the multilink via the redundancy processing unit 145, and causes the multiple links to transmit the uplink data DAT. The radio signals radiated (transmitted) by STA1 and STA2 of the base station AP are received in parallel by STA1 and STA2 of the wireless terminal device WTA, respectively.

[0107] Next, STA1 and STA2 of the wireless terminal device WTA each input the trigger frame TF obtained from the received radio signal to the link management unit MLD of the wireless terminal device WTA (S44). The link management unit MLD of the wireless terminal device WTA checks for duplication of the trigger frame TF input from STA1 and STA2 (S45; duplication check). The trigger frame TFs that have been confirmed to be duplicated are eliminated and input to the link control unit 234 of the management unit 230. Then, based on the received trigger frame TF, the link control unit 234 instructs the MAC frame processing unit 240 to input the uplink data DAT redundantly to STA1 and STA2 of the wireless terminal device WTA (S46). Then, STA1 and STA2 of the wireless terminal device WTA each radiate (transmit) the radio signal including the uplink data DAT via the antenna (S47). Radio signals radiated (transmitted) by STA1 and STA2 of the wireless terminal device WTA, and including uplink data DAT, are received in parallel by STA1 and STA2 of the base station AP, respectively.

[0108] Next, STA1 and STA2 of the wireless terminal device WTA each input the uplink data DAT obtained from the received radio signal to the link management unit MLD of the wireless terminal device WTA (S48). The link management unit MLD of the wireless terminal device WTA checks for duplicates of the uplink data DAT input from STA1 and STA2 (S49; duplicate check). Uplink data DAT that has been found to be duplicated is processed to eliminate the duplicates and input to the data processing unit 120. As a result, the link management unit MLD of the base station AP recognizes that it has successfully received the uplink data DAT.

[0109] Next, the Link Management Unit (MLD) of the base station AP, based on the successful reception of the uplink data DAT, inputs redundant Ack signals to STA1 and STA2 of the base station AP, respectively (S50). Then, STA1 and STA2 of the base station AP each radiate (transmit) a radio signal including the Ack via their antennas (S51). The radio signals radiated (transmitted) by STA1 and STA2 of the base station AP, which include the Ack, are received in parallel by STA1 and STA2 of the wireless terminal device (WTA), respectively.

[0110] Next, STA1 and STA2 of the wireless terminal device WTA each input the Ack obtained from the received radio signal to the link management unit MLD of the wireless terminal device WTA (S52). The link management unit MLD of the wireless terminal device WTA checks for duplicate Ack inputs from STA1 and STA2 (S53; duplicate check). Duplicate Acks are resolved and input to the management unit 230. As a result, the link management unit MLD of the base station AP recognizes that the transmission of the uplink data DAT has been successful. The link management unit MLD of the wireless terminal device WTA then discards the buffered uplink data DAT and completes the transmission of the uplink data DAT.

[0111] Furthermore, the base station AP may transmit information via beacons for each link regarding the transmission suppression period, which is a certain period starting from the TWT cycle, and information about all links subject to transmission suppression. Based on this information, the link management unit MLD of the base station AP, other than the radio terminal equipment WTA that transmits low-latency data, notifies each STA function not to perform channel access on any link. In addition, the link management unit MLD of the base station AP suppresses channel access on links with radio terminal equipment WTAs other than the radio terminal equipment WTA that transmits low-latency data during the transmission suppression period. As a result, while one radio terminal equipment WTA is transmitting low-latency data, the transmission of data by other radio terminal equipment WTAs is prohibited, and interference with radio signals transmitting low-latency data can be suppressed.

[0112] <3> Effects of the Embodiment Multilink data communication achieves efficient communication and improves communication speed by using multiple bandwidths. On the other hand, multilink power consumption is higher than single-link because multiple STA functions are used in both the base station AP and the wireless terminal equipment WTA. For this reason, it is preferable to operate each link constituting the multilink in power-saving mode when there is no traffic congestion. However, if the power-saving mode is operated for a long period, there is a risk of increased delay in uplink data transmission.

[0113] One way to suppress delays in low-latency data on the uplink is to use the Time-Write Time (TWT) function to assign periodic transmissions of uplink data. Specifically, when uplink data is input periodically, it is preferable to match the period of uplink data input with the period of the TWT service. This can suppress the delay time of the low-latency data queue and reduce the power consumption of the multilink. However, if there is interference on the channel at the expected transmission timing, there is a risk that the transmission of low-latency data will fail. If the transmission fails, there is a risk that the low-latency data will not be transmitted within the desired delay time.

[0114] Therefore, the base station AP and wireless terminal device WTA according to this embodiment increase the likelihood of data being transmitted at the intended timing by duplicating low-latency data across multiple links and transmitting it redundantly. Specifically, the base station AP's link management unit MLD, which controls each wireless signal processing unit (STA function), generates information (such as beacons and trigger frames) to be transmitted synchronously (commonly) across multiple links constituting the multilink, and controls its transmission. In addition, the link management unit MLD of the wireless terminal device WTA duplicates data at a common transmission timing across multiple links, outputs it to each STA function, and controls its transmission.

[0115] As a result, in the base station AP and wireless terminal WTA according to this embodiment, when the TWT function is used, data exchanged between the base station AP and the wireless terminal WTA is redundantly transmitted and received in parallel using multilink. Therefore, even if one transmission fails due to interference or other reasons, the data transmitted in parallel between the base station AP and the wireless terminal WTA only needs to be successfully transmitted by the other. Accordingly, the base station AP and wireless terminal WTA according to this embodiment can increase the probability of low-latency data transmission when using the TWT function and can suppress the delay of data transmitted on the uplink.

[0116] <4> others The configuration and functional configuration of the information communication system 1 according to this embodiment may be other configurations. For example, the example given is that each of the base station AP and the wireless terminal device WTA has three STA functions (radio signal processing units), but it is not limited to this. The base station AP only needs to have at least two radio signal processing units. Similarly, the wireless terminal device WTA only needs to have at least two radio signal processing units. The number of channels that each STA function can process can be appropriately set according to the frequency band used. Each of the wireless communication modules 13 and 23 may support wireless communication in multiple frequency bands by using multiple communication modules, or it may support wireless communication in multiple frequency bands with a single communication module. The functional configuration of the base station AP and the wireless terminal device WTA may have other names and groupings as long as they can perform the operations described in the embodiment.

[0117] In the information communication system 1 according to this embodiment, the CPU 10 in the base station AP and the CPU 20 in the wireless terminal device WTA may be other circuits. For example, the base station AP and the wireless terminal device WTA may each be equipped with an MPU (Micro Processing Unit) or the like instead of a CPU. Each of the processes described in the embodiment may be implemented by dedicated hardware. The processes of the base station AP and the wireless terminal device WTA may be a mixture of processes executed by software and processes executed by hardware, or they may consist of only one or the other.

[0118] In the embodiments, the flowcharts used to describe the operation are merely examples. The order of each operation described in the embodiments may be rearranged to the extent possible, and other processes may be added. For example, the multilink setup method described in the embodiments is merely an example. Also, the wireless frame format described in the embodiments is merely an example. In the information communication system 1, other formats may be used as long as it is possible to perform the operations described in the embodiments. For wireless communication between the base station AP and the wireless terminal device WTA, wireless communication standards other than the IEEE 802.11 standard may be used.

[0119] It should be noted that the present invention is not limited to the embodiments described above, and can be modified in various ways during implementation without departing from its essence. Furthermore, each embodiment may be combined as appropriate, and in that case, the combined effects can be obtained. Moreover, the above embodiments include various inventions, and various inventions can be extracted by selecting combinations from the multiple constituent elements disclosed. For example, if the problem can be solved and effects can be obtained even if some constituent elements are deleted from all the constituent elements shown in the embodiment, then the configuration with these deleted constituent elements can be extracted as an invention. [Explanation of symbols]

[0120] AP…Base station WTA... Wireless Terminal Device 1… Information and communication systems 10…CPU 11…ROM 12...RAM 13… Wireless communication module 14…Wired communication module 110...LLC Processing Unit 120...Data Processing Unit 130…Management Department 131…Link Management Information 132... Association Processing Unit 133…Authentication Processing Unit 134...Link Control Unit 135... Beacon Management Department 136…Common time generation unit 137...Trigger generation unit 140…MAC Frame Processing Unit 141...Classification section 142... Send queue 143…Career Sense Execution Department 144…Collision Management Department 145…Redundancy Processing Unit 146... Buffer section 147... Duplicate Check Section 150, 160, 170… Wireless signal processing unit 20…CPU 21…ROM 22...RAM 23… Wireless communication module 24…Display 25…Storage 200...Application execution unit 210...LLC Processing Unit 220...Data Processing Unit 230…Management Department 231…Link Management Information 232... Association Processing Unit 233…Authentication Processing Unit 234...Link Control Unit 235... Beacon Management Department 240…MAC Frame Processing Unit 241...Classification section 242... Send queue 243…Career Sense Execution Department 244…Collision Management Department 245…Redundancy Processing Unit 246... Buffer section 247... Duplicate Check Section 250, 260, 270… Wireless signal processing unit

Claims

1. First wireless signal processing unit, The second wireless signal processing unit, The system includes a link management unit that establishes a multilink with a wireless terminal device using the first wireless signal processing unit and the second wireless signal processing unit, The link management unit generates a trigger frame for transmitting uplink data to the wireless terminal device, and causes the first wireless signal processing unit and the second wireless signal processing unit to transmit the trigger frame to each of them. Base station.

2. The link management unit, when the first wireless signal processing unit and the second wireless signal processing unit receive the first uplink data and the second uplink data in parallel, respectively, checks for duplication between the first uplink data and the second uplink data, and if duplication is confirmed, outputs either the first uplink data or the second uplink data to the upper layer. The base station according to claim 1.

3. The link management unit sets the period for transmitting the trigger frame to the wireless terminal device to match the transmission period of the low-latency data of the wireless terminal device. The base station according to claim 1.

4. The link management unit causes the first radio signal processing unit and the second radio signal processing unit to transmit a beacon containing information regarding the transmission period of the trigger frame, respectively. The base station according to claim 3.

5. First wireless signal processing unit, The second wireless signal processing unit, The system includes a link management unit that establishes a multilink with a base station using the first wireless signal processing unit and the second wireless signal processing unit, When the link management unit receives a trigger frame from the base station instructing the transmission of uplink data, it causes the first radio signal processing unit and the second radio signal processing unit to transmit the uplink data, respectively. Wireless terminal device.

6. The link management unit, when the first wireless signal processing unit and the second wireless signal processing unit each receive the first trigger frame and the second trigger frame in parallel, checks for an overlap between the first trigger frame and the second trigger frame, and if an overlap is confirmed, outputs the uplink data to the first wireless signal processing unit and the second wireless signal processing unit, respectively, using either the first trigger frame or the second trigger frame as the trigger frame. The wireless terminal device according to claim 5.

7. The link management unit, based on information regarding the transmission period of the trigger frame received from the base station, sets the first radio signal processing unit and the second radio signal processing unit, respectively, to a state where they can receive radio signals. The wireless terminal device according to claim 5.

8. The aforementioned uplink data is low-latency data. The link management unit waits to transmit the uplink data until it receives the trigger frame. The wireless terminal device according to claim 7.

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