Base station and wireless terminal device

Abstract

A base station according to an embodiment includes: a first wireless signal processing unit; a second wireless signal processing unit; and a link management unit. The link management unit 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 causing the wireless terminal device to transmit uplink data, and causes each of the first wireless signal processing unit and the second wireless signal processing unit to transmit the trigger frame.

Description

[Technical Field]

[0001] The embodiments relate to a base station and a wireless terminal device. [Background technology]

[0002] 2. Description of the Related Art A wireless LAN (Local Area Network) is known as an information communication system that wirelessly connects a base station and a wireless terminal device. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] IEEE Std 802.11TM-2020, “10.47 Target wake time (TWT)”, published 26 February 2021 Summary of the Invention [Problem to be solved by the invention]

[0004] The challenge is to reduce the delay in data transmitted on the uplink. [Means for solving the problem]

[0005] A base station according to an 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 a wireless terminal device using the first radio signal processing unit and the second radio signal processing unit. The link management unit: Low latency is required A trigger frame for transmitting uplink data to the wireless terminal device is generated, and the trigger frame is transmitted to each of the first wireless signal processing unit and the second wireless signal processing unit. and the uplink data is made redundant. Can. [Effects of the Invention]

[0006] The base station according to the embodiment can suppress delays in data transmitted on the uplink. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a conceptual diagram showing an example of the overall configuration of an information communication system according to an embodiment. [Figure 2] FIG. 2 is a conceptual diagram showing an example of frequency bands used in wireless communication in the information communication system according to the embodiment. [Figure 3] FIG. 3 is a table showing an example of a link state between a base station and a wireless terminal device included in the information communication system according to the embodiment. [Figure 4] FIG. 4 is a block diagram illustrating an example of a hardware configuration of a base station included in the information communication system according to the embodiment. [Figure 5] FIG. 5 is a block diagram showing an example of a hardware configuration of a wireless terminal device included in the information communication system according to the embodiment. [Figure 6] FIG. 6 is a block diagram illustrating an example of a functional configuration of a base station included in the information communication system according to the embodiment. [Figure 7] FIG. 7 is a block diagram illustrating an example of a functional configuration of a MAC frame processing unit of the base station included in the information communication system according to the embodiment. [Figure 8] FIG. 8 is a block diagram illustrating an example of a functional configuration of a wireless terminal device included in the information communication system according to the embodiment. [Figure 9] FIG. 9 is a block diagram illustrating an example of a functional configuration of a MAC frame processing unit of a wireless terminal device included in an information communication system according to the embodiment. [Figure 10] FIG. 10 is a flowchart showing an example of a multi-link setup method in the information communication system according to the embodiment. [Figure 11] FIG. 11 is a sequence diagram showing an outline of a method for transmitting uplink data when a TWT (Target Wake Time) function is used in the information communication system according to the embodiment. [Figure 12]FIG. 12 is a conceptual diagram showing an example of a format of a trigger frame transmitted in a TWT period of the information communication system according to the embodiment. [Figure 13] FIG. 13 is a sequence diagram showing an example of a method for transmitting and receiving a beacon in the information communication system according to the embodiment. [Figure 14] FIG. 14 is a conceptual diagram showing an example of a format of a beacon including a TWT setting used in the information communication system according to the embodiment. [Figure 15] FIG. 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. DETAILED DESCRIPTION OF THE INVENTION

[0008] An information communication system according to an embodiment will be described below with reference to the drawings. Each embodiment illustrates an apparatus or method for embodying the technical idea of ​​the invention. The drawings are schematic or conceptual. In the following description, components having substantially the same functions and configurations are assigned the same reference numerals. Numbers following letters that make up a reference numeral are used to distinguish between 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> An information communication system 1 according to an embodiment will be described below.

[0010] <1> composition <1-1> Overall structure Fig. 1 is a conceptual diagram showing an example of the overall configuration of an information communication system 1 according to an embodiment. As shown in Fig. 1, the information communication system 1 includes, for example, an access point AP, at least one 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 a network NW. The base station AP is configured to be able to wirelessly connect to one or more wireless terminal devices WTA using one or more types of bands. A multilink may be used for the wireless connection between the base station AP and the wireless terminal device WTA. A multilink is a wireless connection that allows data to be transmitted and received using multiple links.

[0012] The wireless terminal device WTA is a wireless terminal such as a smartphone or tablet computer. The wireless terminal device WTA is configured to be able to communicate with the base station AP with which a link has been established. The wireless terminal device WTA may also be an electronic device such as a desktop computer or laptop computer. A terminal identifier AID is assigned to the wireless terminal device WTA. The base station AP can identify multiple wireless terminal devices WTA that are wirelessly connected by the terminal identifier AID. In this example, a wireless terminal device WTA1 with AID=#1 and a 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 able to communicate with the base station AP via the network NW. The server SV stores, for example, content data intended for 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. Communication between the base station AP and the server SV may use wireless communication, or a combination of wireless communication and wired communication.

[0014] Wireless communication between the base station AP and the wireless terminal device WTA complies with the IEEE 802.11 standard. The IEEE 802.11 standard defines Layer 1 and Layer 2 MAC sublayer of the OSI (Open Systems Interconnection) reference model. In the OSI reference 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). Layer 2 (Data Link Layer) includes a Logical Link Control (LLC) sublayer and a Media Access Control (MAC) sublayer. An overview of the LLC sublayer and the MAC sublayer will be provided later.

[0015] Furthermore, the base station AP may use a TWT (Target Wake Time) function for communication with the wireless terminal device WTA. When the TWT function is used, a fixed cycle is set between the base station AP and the wireless terminal device WTA, and the base station AP provides the wireless terminal device WTA with a transmission opportunity at each fixed cycle. The wireless terminal device WTA may reduce power consumption by setting a power-saving state for periods other than the fixed cycle set by the TWT function. In the TWT function, the period during which the base station AP provides the wireless terminal device WTA with a transmission opportunity (hereinafter also referred to as a TWT service period) may be set short when priority is given to reducing power consumption, and set long when priority is given to improving latency. Furthermore, the wireless terminal device WTA may improve the latency of low-latency data by preferentially transmitting data requiring low latency (hereinafter referred to as low-latency data) during the TWT service period. The TWT function in the embodiment executes processing to further reduce the delay in transmission of uplink data from the wireless terminal device WTA to the base station AP. Detailed operation of the TWT function in the embodiment will be described later.

[0016] (Frequency bands used by base stations AP and wireless terminals WTA) FIG. 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 FIG. 2, wireless communication between a base station AP and a wireless terminal device WTA uses, for example, the 2.4 GHz band, the 5 GHz band, and the 6 GHz band. Each frequency band includes multiple channels. FIG. 2 illustrates a case where each of the 2.4 GHz band, the 5 GHz band, and the 6 GHz band includes three channels CH1, CH2, and CH3. Note that frequency bands other than the 2.4 GHz band, the 5 GHz band, and the 6 GHz band may also be used for wireless communication. It is sufficient that at least one channel CH is assigned to each frequency band. Multiple channels CH are used in a multilink. The multiple channels CH used in a multilink may be in the same frequency band or in different frequency bands.

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

[0018] "STA function" indicates a link identifier (Link ID) associated with the STA function. The STA function corresponds to a radio signal processing unit provided in each of the base station AP and the wireless terminal device WTA. Each STA function can use one or more channels. In the following description, it is assumed that each STA function uses one channel. One link is formed by a pair of 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 is established or not. In this example, STA1 and STA2 each indicate that they have established a link ("Yes" in FIG. 3), and STA3 indicates that they have not established a link ("No" in FIG. 3).

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

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

[0022] "Multi-link" indicates whether or not a multi-link has been established. In this example, the pair of STA1 and STA2 has established a multi-link ("◯" in FIG. 3).

[0023] "TID" indicates a traffic type assigned to a link (STA function). TID is an identifier indicating 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 set to a higher priority than other traffic and is traffic that requires low latency (low latency data). "TID" #1 to #3 in FIG. 3 each correspond to one of VO, VI, BE, BK, and 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] In this way, in a multilink, one or more STA functions can be assigned to one TID. The association between traffic and STA functions is set, for example, so that the traffic volume (data volume) is equalized among the multiple links constituting the multilink. This is not limiting, and traffic of similar types (priority / non-priority, etc.) may be concentrated in a specific link constituting 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 WTA will be described below.

[0026] (Base station AP hardware configuration) 4 is a block diagram showing an example of a hardware configuration of a base station AP included in the information communication system 1 according to the embodiment. As shown in FIG. 4, the base station AP includes, for example, a CPU (Central Processing Unit) 10, a ROM (Read Only Memory) 11, a 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 that is used as a work area for the CPU 10. The wireless communication module 13 is a circuit used to transmit and receive 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 to transmit and receive data via wired signals and is configured to be connectable to a network NW. The base station AP may have other hardware configurations. For example, when the base station AP is wirelessly connected to the network NW, the wired communication module 14 may be omitted from the base station AP.

[0028] (Hardware configuration of wireless terminal equipment WTA) 5 is a block diagram showing an example of a hardware configuration of the wireless terminal device WTA included in the information communication system 1 according to the embodiment. As shown in FIG. 5, the wireless terminal device WTA includes, for example, a CPU 20, a ROM 21, a RAM 22, a wireless communication module 23, a display 24, and a 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 that serves as a work area for the CPU 20. The wireless communication module 23 is a circuit used to transmit and receive 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 graphical user interface (GUI) 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, system software for 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 functional configurations of the base station AP and the wireless terminal WTA will be described below.

[0031] (Functional configuration of base station AP) Fig. 6 is a block diagram showing an example of the functional configuration of a base station AP included in the information communication system 1 according to the embodiment. As shown in Fig. 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 realized, for example, by a combination of a CPU 10, a RAM 12, and a wired communication module 14. The processing of each 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 be realized, for example, by a combination of a CPU 10, a RAM 12, and a wireless communication module 13.

[0032] LLC processing unit 110 performs, for example, layer 2 LLC sublayer processing and layer 3 to layer 7 processing on input data. Data processing unit 120, management unit 130, and MAC frame processing unit 140 perform layer 2 MAC sublayer processing on input data. Radio signal processing units 150, 160, and 170 perform layer 1 processing on 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 "link management unit MLD of the base station AP."

[0033] The following describes in detail each of the functional components of the base station AP.

[0034] The LLC processing unit 110 receives data from the server SV, for example, via the network NW. Then, the LLC processing unit 110 generates an LLC packet by adding a DSAP (Destination Service Access Point) header, an SSAP (Source Service Access Point) header, and the like to the received data. Then, the LLC processing unit 110 inputs the generated LLC packet to the data processing unit 120. The LLC processing unit 110 also receives the LLC packet from the data processing unit 120 and extracts data from the received LLC packet. Then, the LLC processing unit 110 transmits the extracted data to the server SV via the network NW.

[0035] The data processing unit 120 generates a MAC frame by adding a MAC header to the LLC packet input from the LLC processing unit 110. 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 a MAC frame from the MAC frame processing unit 140 and extracts an LLC packet from the received MAC frame. The data processing unit 120 then inputs the extracted LLC packet to the LLC processing unit 110. Hereinafter, a MAC frame containing data will also be referred to as a "data frame."

[0036] The management unit 130 manages the state of the link between the base station AP and the wireless terminal WTA. Information relating to link control, management, etc. 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 execute predetermined processing. The management unit 130 includes, for example, link management information 131, an association processing unit 132, an authentication processing unit 133, a link control unit 134, a beacon management unit 135, a common time generation unit 136, and a trigger generation unit 137.

[0037] The link management information 131 is a table containing information about links between the base station AP and the wireless terminals WTA connected wirelessly, and includes, for example, the information shown in FIG.

[0038] When an association request is received from the wireless terminal WTA, the association processing unit 132 executes a protocol related to association.

[0039] The authentication processing unit 133 executes a protocol related to authentication subsequent to association. Hereinafter, a MAC frame including information related to control of association, authentication, etc. will also be referred to as a "management frame."

[0040] The link control unit 134 controls the state of the link with the wireless terminal device WTA connected wirelessly for each AID. Furthermore, when establishing a multi-link, the link control unit 134 can determine the association between the traffic type (TID) and the STA function.

[0041] The beacon management unit 135 manages information transmitted as beacons by the base station AP. The beacon management unit 135 generates, for example, a MAC frame including management information and inputs the MAC frame to 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 that generates time information. The time information is used, for example, when the link control unit 134 uses the TWT function. The time information may be referenced by the MAC frame processing unit 140.

[0043] The trigger generation unit 137 generates a MAC frame including trigger information and inputs it to the MAC frame processing unit 140. The trigger information includes information instructing transmission of uplink data when the TWT function is used. Specifically, the trigger information includes information indicating resources (frequency, transmission timing, and period) for transmission to the wireless terminal apparatus WTA that transmits uplink data when the TWT function is used. Hereinafter, a MAC frame including trigger information will be referred to as a "trigger frame." Note that instead of generating a trigger frame, the trigger generation unit 137 may instruct the MAC frame processing unit 140 to generate a trigger frame together 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. The MAC frame processing unit 140 then references the link management information 131 to identify the link associated with the TID of the data included in the MAC frame. The MAC frame processing unit 140 then performs carrier sensing. Carrier sensing is a process for 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 depending on 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 radio signal processing unit 150 generates a radio frame by adding a preamble, a PHY (physical layer) header, and the like to the data input from the MAC frame processing unit 140. The radio signal processing unit 150 then performs a predetermined modulation operation on the radio frame to convert the radio frame into a radio signal, and radiates (transmits) the radio signal via an antenna. The predetermined modulation operation includes, for example, convolutional coding, interleaving, subcarrier modulation, inverse fast Fourier transform (IFFT), orthogonal frequency division multiplexing (OFDM) modulation, and frequency conversion. The radio signal processing unit 150 also receives a radio signal from the wireless terminal device (WTA) via the antenna, and performs a predetermined demodulation operation on the received radio signal to obtain a radio frame. The predetermined demodulation operation includes, for example, frequency conversion, OFDM demodulation, fast Fourier transform (FFT), subcarrier demodulation, deinterleaving, and Viterbi decoding. Then, the radio signal processing unit 150 extracts a MAC frame from the radio frame and inputs the extracted MAC frame to the MAC frame processing unit 140. The functions of the radio signal processing units 160 and 170 are similar to those of the radio signal processing unit 150. In this example, the radio signal processing units 150, 160, and 170 handle radio signals in the 6 GHz band, 5 GHz band, and 2.4 GHz band, respectively. That is, the radio signal processing units 150, 160, and 170 correspond to STA1, STA2, and STA3 of the base station AP, respectively. The radio signal processing units 150, 160, and 170 may share an antenna or may use separate antennas.

[0046] (Functional configuration of the MAC frame processing unit 140 of the base station AP) Fig. 7 is a block diagram showing an example of a functional configuration of the MAC frame processing unit 140 of the base station AP included in the information communication system 1 according to the embodiment. Fig. 7 shows details of the channel access function and the uplink data receiving 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 Fig. 7, MAC frame processing unit 140 includes, in relation to the channel access function, for example, classification unit 141, transmission queues 142A, 142B, 142C, and 142D, carrier sense execution units 143A, 143B, 143C, and 143D, and collision management unit 144.

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

[0049] Each of the transmit queues 142A, 142B, 142C, and 142D buffers input MAC frames. In this example, the transmit queues 142A, 142B, 142C, and 142D buffer 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) in accordance with access parameters preset for each carrier sense execution unit 143. The access parameters are set for each access category, and are set, for example, so that the transmission of wireless 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, when the carrier sense execution unit 143A acquires the right to transmit (i.e., when the channel is idle), it retrieves a MAC frame from the transmission queue 142A. Then, the carrier sense execution unit 143A outputs the extracted MAC frame via the collision management unit 144 to a radio signal processing unit (for example, one of STA1, STA2, and STA3) corresponding to the link associated with the access category "VO".

[0051] The collision management unit 144 prevents collisions in data transmission when multiple carrier sense execution units 143 acquire the transmission right for the same link. In other words, the collision management unit 144 adjusts the transmission timing of data for which the same STA function has acquired the transmission right, and outputs data of a higher priority access category to the STA function first. Note that, because carrier sense is performed on the trigger frame TF without going through the transmission queue 142, it can be processed with less delay than other traffic. Furthermore, the collision management unit 144 includes a part that functions as a redundancy processing unit 145 when a multi-link is established and the TWT function is used.

[0052] When the traffic for which the transmission right has been acquired by the collision management unit 144 is assigned to multiple links, the redundancy processing unit 145 outputs the MAC frame to be transmitted to each of at least two of the multiple links. In other words, the redundancy processing unit 145 copies (e.g., duplicates) the MAC frame associated with the multiple links and outputs the MAC frame to two or more of the multiple links. The redundancy processing unit 145 may customize the MAC frame to be input to each link so that it has information specific to each link. Alternatively, the redundancy processing unit 145 may copy only common information and input it to each link, causing each link to generate the MAC frame itself. 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 the trigger frame TF 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] Note that, although the embodiment illustrates a case where the MAC frame processing unit 140 implements the channel access function, this is not limiting. For example, the radio signal processing units 150, 160, and 170 may implement the channel access function. In this case, the redundancy processing unit 145 is configured as part of the link management. Specifically, the redundancy processing unit 145 duplicates a frame input from the MAC frame processing unit 140 and inputs the duplicated frame to each corresponding radio signal processing unit. Furthermore, when transmitting a trigger frame TF, the redundancy processing unit 145 notifies each radio signal processing unit of time information generated by the common time generation unit 136. This allows each radio signal processing unit to transmit the trigger frame TF at the same time based on the time information.

[0054] The access parameters used include, for example, CWmin, CWmax, AIFS, and TXOPLimit. CWmin and CWmax respectively indicate the minimum and maximum values ​​of the contention window, which is the transmission waiting time for collision avoidance. AIFS (Arbitration Inter Frame Space) indicates a fixed transmission waiting time set for each access category for collision avoidance control with a priority control function. TXOPLimit indicates the upper limit of TXOP (Transmission Opportunity), which corresponds to the channel occupation time. The shorter the CWmin and CWmax, the easier it is for the transmission queue 142 to obtain the transmission right. The smaller the AIFS, the higher the priority of the transmission queue 142. The larger the value of TXOPLimit, the greater the amount of data transmitted with one transmission right.

[0055] Next, the uplink data reception function in the base station AP will be described. As shown in Fig. 7, the MAC frame processing unit 140 includes, for example, a buffer unit 146 and a duplication check unit 147 in association with the uplink data reception function.

[0056] The buffer unit 146 temporarily stores MAC frames received from each radio signal processing unit (for example, STA1, STA2, and STA3). When a multi-link is established, the buffer unit 146 may store MAC frames containing the same information input from multiple links.

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

[0058] (Functional configuration of wireless terminal device WTA) 8 is a block diagram showing an example of the functional configuration of the wireless terminal device WTA included in the information communication system 1 according to the embodiment. As shown in FIG. 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 radio signal processing units 250, 260, and 270. The processing of the application execution unit 200 and the LLC processing unit 210 may be realized by, for example, the CPU 20 and the RAM 22. The processing of the data processing unit 220, the management unit 230, the MAC frame processing unit 240, and the radio signal processing units 250, 260, and 270 may be realized by, for example, a combination of the CPU 20, the RAM 22, and the 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 layer 3 to layer 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 radio signal processing units 250, 260, and 270 perform layer 1 processing on the input data. Hereinafter, the set of the data processing unit 220, management unit 230, and MAC frame processing unit 240 provided in the wireless terminal apparatus WTA will also be referred to as the "link management unit MLD of the wireless terminal apparatus WTA."

[0060] The following describes in detail each of the functional components of the wireless terminal WTA.

[0061] The application execution unit 200 executes an application that can use data input from the LLC processing unit 210. Furthermore, the application execution unit 200 inputs data to the LLC processing unit 210 and acquires data from the LLC processing unit 210 in accordance with the operation of the application. The application execution unit 200 can display application information on the display 24. Furthermore, the application execution unit 200 can execute processing in accordance with operations performed via an input interface.

[0062] The LLC processing unit 210 generates an LLC packet by adding a DSAP header, an SSAP header, and the like to the data received from the application execution unit 200. Then, the LLC processing unit 210 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. Then, the LLC processing unit 210 inputs the extracted data to the application execution unit 200.

[0063] The data processing unit 220 generates a MAC frame by adding a MAC header to the LLC packet input from the LLC processing unit 210. 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 state of the link between the base station AP and the wireless terminal device WTA. Information related to link control, management, etc. 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 execute predetermined processing. The management unit 230 includes, for example, link management information 231, an association processing unit 232, an authentication processing unit 233, a link control unit 234, and a beacon management unit 235. The link management information 231 is a table containing information related to links with wirelessly connected base stations AP, and includes, for example, the information shown in FIG. 3. The association processing unit 232 executes a protocol related to association when transmitting a connection request to the base station AP. The authentication processing unit 233 executes a protocol related to authentication subsequent to association. The link control unit 234 controls the state of the link with the wirelessly connected base station AP. Furthermore, when establishing a multi-link, the link control unit 234 may determine the association between a traffic type (TID) and an STA function. The beacon management unit 235 manages information included in a beacon received from the base station AP. For example, the beacon management unit 235 receives management information included 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 a MAC frame from the data processing unit 220 or the management unit 230 and temporarily stores (buffers) the received MAC frame. The MAC frame processing unit 240 then references the link management information 231 to identify the link associated with the TID of the data included in the MAC frame. The MAC frame processing unit 240 then 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 depending on 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, the MAC frame processing unit 240 inputs the MAC frame to the management unit 230.

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

[0067] (Functional Configuration of MAC Frame Processing Unit 240 of Wireless Terminal Apparatus WTA) 9 is a block diagram showing an example of a functional configuration of the MAC frame processing unit 240 of the wireless terminal device WTA included in the information communication system 1 according to the embodiment. FIG. 9 shows details of the channel access function and the downlink data receiving 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 Fig. 9, MAC frame processing unit 240 includes, in relation to the channel access function, for example, classification unit 241, transmission queues 242A, 242B, 242C, and 242D, carrier sense execution units 243A, 243B, 243C, and 243D, and collision management unit 244.

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

[0070] Each of the transmit queues 242A, 242B, 242C, and 242D buffers input MAC frames. In this example, the transmit queues 242A, 242B, 242C, and 242D buffer VO, VI, BE, and BK data, respectively.

[0071] Each of the carrier sense execution units 243A, 243B, 243C, 243D, and 243E performs carrier sensing based on CSMA / CA in accordance with access parameters preset for each carrier sense execution unit 243. Each of the carrier sense execution units 243A, 243B, 243C, 243D, and 243E then outputs the MAC frame for which it has acquired the transmission right to the associated link via the collision management unit 244. The access parameters are set, for example, so that the transmission of wireless signals is prioritized in the order of "LL," "VO," "VI," "BE," and "BK." Each of the carrier sense execution units 243A, 243B, 243C, and 243D performs carrier sensing on the MAC frames buffered in the transmission queues 242A, 242B, 242C, and 242D, respectively. The carrier sense execution unit 243E performs carrier sensing on the LL MAC frame received from the classification unit 241. In this way, the MAC frame of LL can be processed with less delay than other traffic because carrier sense is performed on it without going through the transmission queue 242. Note that the carrier sense execution unit 243E may skip carrier sense when the data transmission is in response to the reception of the trigger frame TF.

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

[0073] When the traffic for which the transmission right has been acquired by the collision management unit 244 is assigned to multiple links, the redundancy processing unit 245 outputs the MAC frame to be transmitted to each of at least two of the multiple links. In other words, the redundancy processing unit 245 copies (e.g., duplicates) 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 to be input to each link so that it has information specific to each link. Alternatively, the redundancy processing unit 245 may copy only common information and input it to each link, causing each link to generate the MAC frame itself. When a MAC frame of LL 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 the embodiment, the MAC frame processing unit 240 implements the channel access function, but the present invention is not limited to this. For example, the radio signal processing units 250, 260, and 270 may implement the channel access function.

[0075] Next, a description will be given of the downlink data reception function of the wireless terminal WTA. As shown in Fig. 9, the MAC frame processing unit 240 includes, for example, a buffer unit 246 and a duplication check 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 (for example, STA1, STA2, and STA3). When a multi-link is established, the buffer unit 246 may store MAC frames containing the same information input from multiple links.

[0077] The duplication checker 247 checks the MAC frames stored in the buffer unit 246 and discards all but one frame containing duplicate information. The duplication checker 247 then outputs the MAC frame from which the duplication has been eliminated to the data processing unit 220 or the management unit 230, depending on the type of MAC frame. The duplication checker 247 checks for duplication by, for example, referring to a sequence number included in the MAC header. The duplication checker 247 only needs to use common information included in the MAC frame to check for duplication. For example, when the duplication checker 247 checks that the buffer unit 246 has received and stored beacons containing the same information from multiple links, it eliminates the duplication and outputs the information to the beacon management unit 235. When the duplication checker 247 checks that the buffer unit 246 has received and stored trigger frames specifying the same TWT service period from multiple links, it eliminates the duplication 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 multi-link Fig. 10 is a flowchart showing an example of a multi-link setup method in the information communication system 1 according to the embodiment. The multi-link setup method will be described below with reference to Fig. 10. The multi-link 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 by using, for example, a management frame.

[0079] In the process of S10, the wireless terminal device WTA transmits (broadcasts) a probe request to the base station AP. The probe request is a signal to check whether the base station AP is present in the vicinity of the wireless terminal device WTA. Upon receiving the probe request, the base station AP executes the process of S11.

[0080] In the process of S11, the base station AP transmits a probe response to the wireless terminal device WTA. The probe response is a signal used in response to a probe request from the wireless terminal device WTA, and includes information necessary for establishing a multilink. Upon receiving the probe response, the wireless terminal device WTA executes the process of S12.

[0081] In the process of S12, the wireless terminal device WTA transmits 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 requesting the base station AP to establish a multilink and includes information for a multilink connection. Upon receiving the multilink association request, the link management unit MLD of the base station AP executes the process of S13.

[0082] In the process of S13, the link management unit MLD of the base station AP executes a multi-link association process. In the multi-link association process, the base station AP first executes an association process of a first STA function with the wireless terminal device WTA. Then, when a wireless connection (link) is established in the first STA function, the link management unit MLD of the base station AP executes an association process of a second STA function using the first STA function with which the link is established. When the association processes of at least two STA functions are completed, the base station AP recognizes that a multi-link with the wireless terminal device WTA has been established, and executes the process of S14.

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

[0084] In the process of S15, the base station AP transmits a multilink establishment response to the wireless terminal device WTA. The multilink establishment response is a signal used in response 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 with the base station AP has been established based on the reception of the multilink establishment response, and executes the process of S16.

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

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

[0087] Furthermore, when setting up a multilink, the link management units MLD of the base station AP and the wireless terminal WTA perform mapping between each link included in the multilink and a traffic type (TID). Specifically, the link management unit MLD of the wireless terminal WTA determines the association between traffic and links and requests the link management unit MLD of the base station AP to apply the association. After that, when the wireless terminal WTA receives an acknowledgment for the request from the base station AP, the association between traffic and links is confirmed. For example, low-latency data (traffic) is associated with at least two of the multiple links constituting the multilink. The traffic associated with the multiple links can be redundantly transmitted by the redundancy processing unit 145 or 245. Note that "traffic being redundantly transmitted" corresponds to the same traffic being transmitted over the multiple links constituting the multilink.

[0088] <2-2>TWT function The TWT function in this embodiment will be described in detail below.

[0089] The link management unit MLD of the base station AP or the wireless terminal WTA sets up the TWT function, for example, to exchange low-latency data. The TWT function may be set up when setting up a multilink, or may be set up based on a low-latency data transmission request from the wireless terminal WTA after the multilink has been established. Parameters used in the TWT function (hereinafter referred to as TWT settings) are set by the link management unit MLD of each of the base station AP and the wireless terminal WTA. The base station AP may manage the TWT settings for each wireless terminal WTA or for each group. In the embodiment, a case will be described in which the base station AP manages the TWT settings for each group. Hereinafter, a group that shares TWT settings will be referred to as a "TWT group." When using the TWT function, the base station AP assigns wireless terminal WTAs with which it has established a link to a TWT group.

[0090] The TWT settings are managed by the management unit 130 of the base station AP and the management unit 230 of the wireless terminal WTA. The TWT settings include, for example, a TWT start time, a TWT period, and a 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 a TWT interval. The TWT duration corresponds to the period during which a transmission opportunity is provided to the wireless terminal WTA. During the TWT duration, multiple links that have established a multilink with the base station AP are set to a state in which they can receive wireless signals. When the TWT function is used, one period 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 device WTA waits until the TWT service period begins before transmitting low-latency data, and transmits the low-latency data to each link based on the reception of a trigger frame TF during the TWT service period. The cycle of the TWT service period is preferably set to match the transmission cycle of the low-latency data of the wireless terminal device WTA. The link management unit MLD of the base station AP may obtain the transmission cycle of the low-latency data to be reflected in the TWT setting by any method. For example, the link management unit MLD of the base station AP may obtain, from the wireless terminal device WTA, a data generation cycle set in an application that generates low-latency data, and determine the TWT setting.

[0092] The TWT start time may be expressed in terms of the TWT period. The wireless terminal apparatus WTA may 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 apparatus WTA may 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 how uplink data is transmitted) 11 is a sequence diagram showing an example of a method for transmitting uplink data when the TWT function is used in the information communication system 1 according to the embodiment. <1> and <2> 1 illustrates an example in which uplink data is transmitted at each of the TWT intervals TI. <1> and <2> Each of the uplink data transmission methods has a TWT duration TD and a waiting period WP. The waiting period WP corresponds to a period during which no transmission opportunity is provided while the TWT function is in use. An overview of the uplink data transmission method will be described below with reference to FIG. 11.

[0094] The wireless terminal WTA transmits the TWT interval TI <1> Before the TWT interval TI, the uplink data DAT1 is buffered (S20). <1> When the start time of the TWT interval TD arrives, the base station AP transmits a trigger frame TF to the wireless terminal WTA within the TWT duration TD (S21). The timing at which the trigger frame TF is transmitted 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 may transmit the trigger frame TF by a preferential transmission means different from EDCA. The wireless terminal WTA transmits uplink data DAT1 to the base station AP based on the reception of the trigger frame TF (S22). When the base station AP successfully receives the uplink data DAT1, it transmits an Ack to the wireless terminal WTA (S23). By receiving the Ack after transmitting the uplink data DAT1, the wireless terminal WTA recognizes that the transmission of DAT1 was successful and discards DAT1. The processes of S21 to S23 are performed during the TWT interval TI <1> The TWT is executed within the TWT duration TD.

[0095] TWT interval TI <1> When the TWT duration TD ends within the TWT interval TI, the waiting period WP begins. <1> During the waiting period WP, ​​the wireless terminal WTA buffers the uplink data DAT2 (S24). <2> When the start time of the TWT interval TI arrives, the base station AP transmits a trigger frame TF to the wireless terminal device WTA within the TWT duration TD (S25). The wireless terminal device WTA transmits uplink data DAT2 to the base station AP based on the reception of the trigger frame TF (S26). When the base station AP successfully receives the uplink data DAT2, it transmits an Ack to the wireless terminal device WTA (S27). By receiving an Ack after transmitting the uplink data DAT2, the wireless terminal device WTA recognizes that the transmission of DAT2 was successful and discards DAT2. The processing of S25 to S27 is performed during the TWT interval TI <2> The TWT is performed within the TWT duration TD. <2> There will be a waiting period of WP.

[0096] As described above, when the TWT function is used, the access point AP notifies the wireless terminal WTA of a data transmission opportunity using a trigger frame TF during the TWT duration TD of each TWT interval TI. Then, each time the wireless terminal WTA receives a trigger frame TF, it attempts to transmit buffered data to the access point AP.

[0097] (Trigger frame TF format) 12 is a conceptual diagram showing an example of a format of a trigger frame transmitted during a TWT period of an information communication system according to an embodiment. As shown in FIG. 12, the multiple fields included in the trigger frame include, 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 period for using the wireless link. The address field includes 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, an "AID" and an "RU (Resource Unit) Allocation." The wireless terminal device WTA recognizes that the allocation is intended for its own station by the AID. The wireless terminal device WTA also recognizes the allocated resources by the RU allocation. The padding is an area used to adjust the data length of the wireless frame. The FCS field stores an error detection code for the MAC header and frame body field pair, and is used to determine whether or not there is an error in the data frame.

[0099] (TWT setting notification method) The base station AP uses, for example, a beacon as a method for notifying the wireless terminal device WTA of the TWT setting. The beacon including the TWT setting is generated and transmitted, for example, by the beacon management unit 135 of the base station AP. Furthermore, the TWT setting included in the beacon received by the wireless terminal device WTA is acquired and managed by the beacon management unit 235. As a result, the beacon management unit 135 of the base station AP can notify the wireless terminal device WTA of the TWT service period for transmitting low-latency data. The redundancy processing unit 145 of the base station AP may include the beacon in the frames to be made redundant. In other words, the beacon management unit 135 can transmit, to each link, a beacon announcing the TWT setting, such as the TWT start time and TWT duration, for transmitting low-latency data.

[0100] 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. Hereinafter, with reference to FIG. 13, an example of a TWT setting notification method in a case where a multi-link is established when the TWT function is used will be described.

[0101] First, the link management unit MLD of the base station AP generates a beacon BE including a 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 each of STA1 and STA2 of the base station AP (S31). Then, each of STA1 and STA2 of the base station AP radiates (transmits) a radio signal including the beacon BE via an antenna (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, each of STA1 and STA2 of the wireless terminal apparatus WTA inputs the beacon BE acquired from the received wireless signal to the link management unit MLD of the wireless terminal apparatus WTA (S33). The link management unit MLD of the wireless terminal apparatus WTA checks whether the beacons input from STA1 and STA2 are duplicated (S34: duplicate check). Beacons for which duplication has been confirmed are eliminated and input to the beacon management unit 235 of the management unit 230. The beacon management unit 235 then updates the TWT setting based on the TWT setting included in the received beacon (S35: setting update).

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

[0104] The TWT setting for each AID included in the beacon includes, for example, a TWT start time, a TWT duration, and a transmission suppression period. The transmission suppression period indicates a period during which uplink data transmission is suppressed or prohibited for the wireless terminal device WTA. The wireless terminal device WTA suppresses or prohibits uplink data transmission during the specified transmission suppression period. Upon receiving a beacon, the beacon management unit 235 of each wireless terminal device WTA acquires 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 uplink data transmission during the TWT service period during which low-latency data is transmitted for wireless terminal devices WTA other than the wireless terminal device WTA assigned to transmit low-latency data, among multiple wireless terminal devices WTA connected wirelessly.

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

[0106] Before the TWT service period, the link management unit MLD of the wireless terminal apparatus WTA buffers the uplink data DAT, for example, in the MAC frame processing unit 240 (S40). When the TWT service period starts, the link management unit MLD of the base station AP generates a trigger frame TF (S41; trigger generation). Then, the link management unit MLD of the base station AP makes the trigger frame TF redundant using the redundancy processing unit 145 and inputs the redundant trigger frame TF to each of the STA1 and STA2 of the base station AP (S42). Then, each of the STA1 and STA2 of the base station AP radiates (transmits) a radio signal including the trigger frame TF via an antenna (S43). In other words, in the processing of S41 to S43, the trigger generation unit 137 generates a trigger frame TF for transmitting the uplink data DAT to the wireless terminal apparatus WTA, inputs the trigger frame TF 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. Radio signals emitted (transmitted) by STA1 and STA2 of the base station AP are received in parallel by STA1 and STA2 of the wireless terminals WTA, respectively.

[0107] Next, each of STA1 and STA2 of the wireless terminal apparatus WTA inputs a trigger frame TF acquired from the received wireless signal to the link management unit MLD of the wireless terminal apparatus WTA (S44). The link management unit MLD of the wireless terminal apparatus WTA checks whether the trigger frames TF input from each of STA1 and STA2 are duplicated (S45: duplicate check). If a duplicate trigger frame TF is confirmed, the duplicate is 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 causes the MAC frame processing unit 240 to make the uplink data DAT redundant and input it to each of STA1 and STA2 of the wireless terminal apparatus WTA (S46). Then, each of STA1 and STA2 of the wireless terminal apparatus WTA radiates (transmits) a wireless signal including the uplink data DAT via an antenna (S47). Radio signals emitted (transmitted) by the wireless terminals WTA STA1 and STA2 and containing uplink data DAT are received in parallel by the base station AP STA1 and STA2, respectively.

[0108] Next, each of STA1 and STA2 of the wireless terminal apparatus WTA inputs the uplink data DAT acquired from the received wireless signal to the link management unit MLD of the wireless terminal apparatus WTA (S48). The link management unit MLD of the wireless terminal apparatus WTA checks whether the uplink data DAT input from each of STA1 and STA2 is duplicated (S49: duplicate check). If duplicated uplink data DAT is confirmed, the duplicate is eliminated 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, makes the Ack redundant and inputs it to each of STA1 and STA2 of the base station AP (S50). Then, each of STA1 and STA2 of the base station AP radiates (transmits) a radio signal including the Ack via an antenna (S51). The radio signals radiated (transmitted) by STA1 and STA2 of the base station AP and including the Ack are received in parallel by STA1 and STA2 of the wireless terminal device WTA, respectively.

[0110] Next, each of STA1 and STA2 of the wireless terminal apparatus WTA inputs the Ack acquired from the received wireless signal to the link management unit MLD of the wireless terminal apparatus WTA (S52). The link management unit MLD of the wireless terminal apparatus WTA checks whether the Acks input from STA1 and STA2 are duplicated (S53: duplication check). If a duplication is confirmed, the Ack is eliminated and input to the management unit 230. This allows the link management unit MLD of the base station AP to recognize that the transmission of the uplink data DAT has been successful. The link management unit MLD of the wireless terminal apparatus WTA then discards the buffered uplink data DAT and completes the transmission of the uplink data DAT.

[0111] The base station AP may transmit, in a beacon, information about a transmission suppression period for a certain period starting from the TWT cycle for each link, and information about all links subject to transmission suppression. Based on this information, the link management units MLD of the wireless terminal devices WTA other than the wireless terminal device WTA transmitting low-latency data notify each STA function not to perform channel access on any link. Furthermore, during the transmission suppression period, the link management unit MLD of the base station AP suppresses channel access on links with wireless terminal devices WTA other than the wireless terminal device WTA transmitting low-latency data. As a result, while a wireless terminal device WTA is transmitting low-latency data, data transmission by other wireless terminal devices WTA is prohibited, and interference with wireless signals transmitting low-latency data can be suppressed.

[0112] <3> Effects of the embodiment Multilink data communication can achieve efficient communication and improve communication speed by using multiple bands. However, multilink power consumption is higher than single-link power consumption because multiple STA functions are used in each of the base station AP and the wireless terminal device WTA. For this reason, when there is no traffic congestion, it is preferable to operate each link constituting the multilink in power-saving mode. However, if the power-saving mode is operated for a long period of time, there is a risk of a large delay in transmitting uplink data.

[0113] One possible method for suppressing the delay of low-latency data in the uplink is to allocate periodic transmission of uplink data using the TWT function. Specifically, when uplink data is input periodically, it is preferable to match the period at which the uplink data is input with the period of the TWT service period. This can suppress the queue delay time of the low-latency data and reduce power consumption of the multilink. However, if there is interference on the channel at the expected transmission timing, the transmission of the low-latency data may fail. If the transmission fails, the low-latency data may not be transmitted within the desired delay time.

[0114] Therefore, the base station AP and wireless terminal device WTA according to the embodiment increase the possibility of transmitting data at the expected timing by duplicating low-latency data to multiple links and transmitting the data redundantly. Specifically, the base station AP has a link management unit MLD that controls each wireless signal processing unit (STA function) to generate information (beacons, trigger frames, etc.) to be transmitted synchronously (shared) across multiple links constituting the multi-link, and controls the transmission. Also, the link management unit MLD of the wireless terminal device WTA duplicates data at the shared transmission timing across the multiple links, outputs it to each STA function, and controls the transmission.

[0115] As a result, in the base station AP and wireless terminal device WTA according to the embodiment, when using the TWT function, data exchanged between the base station AP and the wireless terminal device WTA is redundantly transmitted and received in parallel using multilinks. Therefore, even if one transmission of data transmitted in parallel between the base station AP and the wireless terminal device WTA fails due to interference or the like, it is sufficient if the other transmission is successful. Therefore, the base station AP and wireless terminal device WTA according to the embodiment can increase the probability of transmitting low-latency data when using the TWT function, and can reduce the delay of data transmitted in the uplink.

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

[0117] In the information communication system 1 according to the embodiment, the CPU 10 included in the base station AP and the CPU 20 included in the wireless terminal device WTA may each 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) instead of a CPU. Each of the processes described in the embodiment may be realized 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 may be only one of them.

[0118] In the embodiments, the flowcharts used to explain the operations are merely examples. The order of the processes of each operation described in the embodiments may be changed as far as possible, and other processes may be added. For example, the multi-link setup method described in the embodiments is merely an example. Furthermore, 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 they are capable of executing the operations described in the embodiments. A wireless communication standard other than the IEEE 802.11 standard may be used for wireless communication between the base station AP and the wireless terminal device WTA.

[0119] 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 elements from the disclosed elements. For example, if the problem can be solved and the desired effect can be obtained even if some elements are deleted from all elements shown in the embodiments, the configuration from which these elements are deleted can be extracted as an invention. [Explanation of symbols]

[0120] AP…Base station WTA: Wireless Terminal Equipment 1. Information and communication systems 10...CPU 11...ROM 12...RAM 13...Wireless communication module 14...Wired communication module 110...LLC Processing Section 120...Data processing unit 130...Management Department 131...Link management information 132...Association processing unit 133...Authentication processing unit 134...Link control section 135...Beacon Management Department 136…Common time generation unit 137...Trigger generation unit 140...MAC frame processing unit 141...Classification section 142...Transmission queue 143...Career Sense Executive Department 144…Collision Management Department 145...Redundancy processing unit 146...Buffer section 147…Duplicate confirmation section 150, 160, 170...Radio signal processing unit 20...CPU 21...ROM 22...RAM 23...Wireless communication module 24…Display 25…Storage 200...Application execution unit 210...LLC Processing Section 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...Transmission queue 243…Career Sense Executive Department 244…Collision Management Department 245...Redundancy processing unit 246...Buffer section 247…Duplicate confirmation section 250, 260, 270...Radio signal processing unit

Claims

1. a first radio signal processing unit; a second radio signal processing unit; a link management unit that establishes a multi-link 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 requiring low latency 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, thereby making the uplink data redundant; Base station.

2. the link management unit, when the first radio signal processing unit and the second radio signal processing unit receive the first uplink data and the second uplink data in parallel, respectively, confirms overlapping between the first uplink data and the second uplink data, and when overlapping is confirmed, outputs either the first uplink data or the second uplink data to an upper layer; The base station of claim 1 .

3. the link management unit sets a period for transmitting the trigger frame to the wireless terminal device in accordance with a period for transmitting low-latency data from the wireless terminal device; The base station of claim 1 .

4. the link management unit causes each of the first radio signal processing unit and the second radio signal processing unit to transmit a beacon including information related to a transmission cycle of the trigger frame; The base station according to claim 3 .

5. a first radio signal processing unit; a second radio signal processing unit; a link management unit that establishes a multi-link with a base station using the first radio signal processing unit and the second radio signal processing unit, When the link management unit receives a trigger frame instructing transmission of uplink data requiring low latency from the base station, the link management unit makes the uplink data redundant and causes the first radio signal processing unit and the second radio signal processing unit to transmit the redundant uplink data, respectively. Wireless terminal device.

6. the link management unit, when the first radio signal processing unit and the second radio signal processing unit receive a first trigger frame and a second trigger frame in parallel, respectively, confirms whether the first trigger frame and the second trigger frame overlap, and, when the overlap is confirmed, outputs the uplink data to each of the first radio signal processing unit and the second radio signal processing unit, using either the first trigger frame or the second trigger frame as the trigger frame; 6. The wireless terminal device according to claim 5.

7. the link management unit sets each of the first radio signal processing unit and the second radio signal processing unit to a state in which they can receive radio signals, based on information regarding a transmission cycle of the trigger frame received from the base station.

6. The wireless terminal device according to claim 5.

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

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