Access point, transmission station, and reception station

Abstract

An access point according to an embodiment is included in an information communication system that comprises a transmission station, a plurality of access points, and a reception station, and that distributes traffic among the plurality of access points and transfers data from the transmission station to the reception station. The access point includes a reception status management unit and a transmission buffer control unit. The reception status management unit updates reception success / failure information indicating the reception status of data stored in a transmission buffer on the basis of a starting sequence number and a bitmap that are included in a received acknowledgment frame. The transmission buffer control unit stores data received via a first radio link or a third radio link in the transmission buffer, determines data to be transmitted via the first radio link or a second radio link among the data stored in the transmission buffer on the basis of a transmission window, and shifts the transmission window on the basis of the starting sequence number included in the acknowledgment frame.

Description

Access points, transmitting stations, and receiving stations

[0001] The embodiments relate to an access point, a transmitting station, and a receiving station.

[0002] Wireless LANs (local area networks) are known as information communication systems that wirelessly connect access points (APs) and terminal devices. Terminal devices can access the network via access points within the communication area of ​​a wireless LAN. The Ultra High Reliability - Study Group (UHR-SG), which is studying next-generation wireless LAN systems based on the IEEE 802.11 standard, is studying a multi-AP function that allows multiple access points to operate in coordination.

[0003] In one form of the multi-AP function, multiple second access points connected to a first access point cooperate to perform data communication between the first access point and a terminal device. One example of cooperative operation between multiple second access points is offloading, which distributes traffic between the first access point and a non-AP_MLD (non-access point multi link device) to each second access point. The non-AP_MLD corresponds to a functional block in the terminal device that manages wireless connections using the multi-AP function.

[0004] Furthermore, the IEEE 802.11 standard uses BlockAck to share reception status between a data transmitting device (transmitting station) and a data receiving device (receiving station). This allows the transmitting station to confirm that data has been delivered to the receiving station and to control the transmission buffer that stores the data to be transmitted to the receiving station. For example, buffer control using BlockAck deletes data whose reception has been confirmed from the transmission buffer and performs window control for transmitting the next data.

[0005] IEEE Std 802.11TM-2020, “6.3.27 Block Ack”, p436-p442, December 2020

[0006] However, when the multi-AP function is used, not all traffic passes through each of the second access points. As a result, each second access point cannot confirm the reception of data that does not pass through it, and it is unable to appropriately shift the window of its transmission buffer. In this way, when traffic is distributed to multiple second access points using the multi-AP function, buffer control at the second access points becomes a problem.

[0007] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an access point, a transmitting station, and a receiving station that can appropriately control buffer windows throughout an information communication system when the multi-AP function is used.

[0008] An access point according to an embodiment is included in an information communication system including a transmitting station, an access point having a first wireless link established with the transmitting station, another access point having a second wireless link established with the transmitting station, and a receiving station having a third wireless link with the access point and a fourth wireless link established with the other access point, and which allocates traffic between the access point and the other access points and transfers data from the transmitting station to the receiving station. The access point includes a reception status management unit and a transmission buffer control unit. The reception status management unit is configured to update reception success / failure information indicating the reception status of data stored in a transmission buffer based on a start sequence number and a bitmap included in a reception confirmation frame received via the first wireless link or the third wireless link. The transmission buffer control unit is configured to store data received via the first wireless link or the third wireless link in a transmission buffer, determine which data from the data stored in the transmission buffer is to be transmitted via the first wireless link or the second wireless link based on a transmission window, and shift the transmission window based on the start sequence number included in the reception confirmation frame.

[0009] According to the present invention, it is possible to provide an access point, a transmitting station, and a receiving station that can appropriately control the window of the transmission buffer in the entire information communication system when the multi-AP function is used.

[0010] FIG. 1 is a block diagram showing an example of the overall configuration of an information and communication system according to an embodiment. FIG. 2 is a block diagram showing an example of the hardware configuration of a sharing access point included in the information and communication system according to an embodiment. FIG. 3 is a block diagram showing an example of the hardware configuration of a shared access point included in the information and communication system according to an embodiment. FIG. 4 is a block diagram showing an example of the hardware configuration of a terminal device included in the information and communication system according to an embodiment. FIG. 5 is a block diagram showing an example of the functional configuration of a sharing access point included in the information and communication system according to an embodiment. FIG. 6 is a block diagram showing an example of the functional configuration of a frame processing unit included in a sharing access point included in the information and communication system according to an embodiment. FIG. 7 is a block diagram showing an example of the functional configuration of a shared access point included in the information and communication system according to an embodiment. FIG. 8 is a block diagram showing an example of the functional configuration of a frame processing unit included in a shared access point included in the information and communication system according to an embodiment. FIG. 9 is a block diagram showing an example of the functional configuration of a terminal device included in the information and communication system according to an embodiment. FIG. 10 is a block diagram showing an example of the functional configuration of a frame processing unit included in the terminal device included in the information and communication system according to an embodiment. FIG. 11 is a block diagram showing an example of the functional configuration of an affiliated STA included in the terminal device included in the information and communication system according to an embodiment. FIG. 12 is a schematic diagram showing an example of a MAC sublayer architecture in the information and communication system according to an embodiment. Fig. 13 is a table showing an example of the configuration of a transmission buffer of a transmitting station in an information communication system according to an embodiment. Fig. 14 is a time chart showing an example of a setup sequence for multi-AP connection in the information communication system according to an embodiment. Fig. 15 is a block diagram showing an example of a data transfer method in the information communication system according to an embodiment. Fig. 16 is a flowchart showing an example of a window control method for a shared access point included in the information communication system according to an embodiment. Fig. 17 is a flowchart showing an example of a window control method for a shared access point included in the information communication system according to an embodiment.Fig. 18 is a schematic diagram showing a specific example of a method for managing a transmission buffer of a shared access point included in an information communication system according to an embodiment. Fig. 19 is a flowchart showing an example of a window control method for a terminal device included in an information communication system according to an embodiment. Fig. 20A is a time chart showing a specific example of a data transfer sequence of an information communication system according to an embodiment. Fig. 20B is a time chart showing a specific example of a data transfer sequence of an information communication system according to an embodiment.

[0011] An information communication system according to an embodiment will be described below with reference to the drawings. The embodiments illustrate devices and methods for embodying the technical concepts of the invention. The drawings are schematic or conceptual. Hereinafter, the same reference numerals are used to designate components having substantially the same functions and configurations. The numerals following the letters in a reference numeral are used to distinguish between elements having similar configurations and referenced by the same reference numerals. Similarly, the letters and "hyphen + numeral" following the numerals in a reference numeral are used to distinguish between elements having similar configurations and referenced by the same reference numerals. When there is no need to distinguish between elements indicated by the same reference numerals, these elements are referred to by the reference numerals containing only the letters or numerals. Hereinafter, "access point" will be abbreviated to "AP" as appropriate. In this specification, a first access point in a multi-AP function is referred to as a "sharing AP," and a second access point in a multi-AP function is referred to as a "shared AP."

[0012] <1> Configuration First, a configuration of the information communication system 1 according to the embodiment will be described. The following description will be given on the assumption that a multi-AP connection using a multi-AP function has been established in the information communication system 1.

[0013] <1-1> Overall configuration of information communication system 1 Fig. 1 is a block 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 a sharing AP 10, a plurality of shared APs 20, and a terminal device 30.

[0014] The sharing AP 10 is a type of wireless LAN access point. The sharing AP 10 is connected to a network NW. The sharing AP 10 is configured to be able to communicate by wire or wireless with a server (not shown) on the network NW, and to be able to communicate wirelessly with each of the multiple shared APs 20. The sharing AP 10 establishes a multi-AP connection with the non-AP_MLD of the terminal device 30.

[0015] The shared AP 20 is a type of wireless LAN access point. The shared AP 20 is configured to be able to wirelessly communicate with both the sharing AP 10 and the terminal device 30. Multiple shared APs 20 are installed at locations distant from each other and have different communication areas. The communication area of ​​each shared AP 20 may overlap with the communication area of ​​another shared AP 20. Figure 1 shows two shared APs 20-1 and 20-2 connected to the sharing AP 10.

[0016] The terminal device 30 is a wireless terminal such as a smartphone or a PC (Personal Computer). The terminal device 30 has multiple affiliated stations (STAs) (hereinafter also referred to as "A-STAs") and a non-AP_MLD. The multiple affiliated STAs include A-STA1 wirelessly connected to a shared AP 20-1 and A-STA2 wirelessly connected to a shared AP 20-2. The wireless connection between the shared AP 20 and the affiliated STAs corresponds to a conventional connection between a pair of access points and an STA. Each A-STA can switch its connection destination to another shared AP 20 as the terminal device 30 moves. The non-AP_MLD is a multi-link device (MLD) that manages the link status and wireless communication of each of the multiple A-STAs. The non-AP_MLD can establish a multi-AP connection with the sharing AP 10 via a plurality of affiliated STAs and a plurality of shared APs 20, and exchange data and the like.

[0017] When a multi-AP connection is established in the information communication system 1, information on the multiple shared APs 20 under the sharing AP 10 and information on the multiple affiliated STAs under the non-AP_MLD are mutually exchanged between the sharing AP 10 and the non-AP_MLD. This allows the information communication system 1 to collectively establish a comprehensive connection between the sharing AP 10 and the non-AP_MLD for the multiple shared APs 20 and the multiple affiliated STAs.

[0018] The wireless communication used in the information communication system 1 complies with, for example, the IEEE 802.11 standard. The IEEE 802.11 standard has wireless communication functions based on the OSI (Open Systems Interconnection) reference model. In the OSI reference model, wireless communication functions are divided into seven layers (Layer 1: Physical Layer, Layer 2: Data Link Layer, Layer 3: Network Layer, Layer 4: Transport Layer, Layer 5: Session Layer, Layer 6: Presentation Layer, and Layer 7: Application Layer). The data link layer includes an LLC (Logical Link Control) sublayer and a MAC (Media Access Control) sublayer. Frequency bands used in the wireless communication of the information communication system 1 may include, for example, the 2.4 GHz band, the 5 GHz band, the 6 GHz band, the 45 GHz band, and the 60 GHz band. Multiple channels may be assigned to each frequency band. Different channels or the same channel may be assigned to A-STA1 and A-STA2. Furthermore, A-STA1 and A-STA2 may use the same frequency band, or different frequency bands.

[0019] <1-2> Hardware Configuration of Information Communication System 1 Hereinafter, the hardware configuration of the information communication system 1 according to the embodiment will be described.

[0020] 2 is a block diagram showing an example of the hardware configuration of the sharing AP 10 included in the information communication system 1 according to the embodiment. As shown in FIG. 2, the sharing AP 10 includes, for example, a CPU (Central Processing Unit) 11, a ROM (Read Only Memory) 12, a RAM (Random Access Memory) 13, a wireless communication module 14, and a wired communication module 15.

[0021] The CPU 11 is an integrated circuit capable of executing various programs and controls the overall operation of the sharing AP 10. The ROM 12 is, for example, a non-volatile semiconductor memory that stores programs and control data for controlling the sharing AP 10. The RAM 13 is, for example, a volatile semiconductor memory that is used as a work area for the CPU 11. The wireless communication module 14 is configured to be able to send and receive wireless signals via an antenna. The wireless communication module 14 is used to send and receive data, etc., to and from each shared AP 20. The wired communication module 15 is a circuit used to send and receive data, etc., via wired signals. The wired communication module 15 is configured to be connectable to a network NW.

[0022] The sharing AP 10 may have other hardware configurations. For example, when the sharing AP 10 is wirelessly connected to the network NW, the wired communication module 15 may be omitted from the sharing AP 10. When the sharing AP 10 is wiredly connected to the network NW, the wireless communication module 14 may be omitted from the sharing AP 10. The antenna may be built into the sharing AP 10 or may be externally connected.

[0023] <1-2-2> Hardware Configuration of Shared AP 20 Fig. 3 is a block diagram showing an example of the hardware configuration of the shared AP 20 included in the information communication system 1 according to the embodiment. As shown in Fig. 3, as shown in Fig. 2, the shared AP 20 includes, for example, a CPU 21, a ROM 22, a RAM 23, and a wireless communication module 24.

[0024] The CPU 21 is an integrated circuit capable of executing various programs and controls the overall operation of the shared AP 20. The ROM 22 is, for example, a non-volatile semiconductor memory and stores programs and control data for controlling the shared AP 20. The RAM 23 is, for example, a volatile semiconductor memory and is used as a work area for the CPU 21. The wireless communication module 24 is configured to be able to send and receive wireless signals via an antenna. The wireless communication module 24 is used to send and receive data, etc., to and from the sharing AP 10 and to and from the terminal device 30.

[0025] The shared AP 20 may have other hardware configurations. For example, the antenna may be built into the shared AP 20 or may be externally connected.

[0026] 4 is a block diagram showing an example of the hardware configuration of the terminal device 30 included in the information communication system 1 according to the embodiment. As shown in FIG. 4, the terminal device 30 includes, for example, a CPU 31, a ROM 32, a RAM 33, a wireless communication module 34, a display 35, and a storage 36.

[0027] The CPU 31 is an integrated circuit capable of executing various programs and controls the overall operation of the terminal device 30. The ROM 32 is, for example, a non-volatile semiconductor memory and stores programs and control data for controlling the terminal device 30. The RAM 33 is, for example, a volatile semiconductor memory and is used as a work area for the CPU 31. The wireless communication module 34 is configured to be able to send and receive wireless signals via an antenna. The wireless communication module 34 is used to send and receive data to and from the shared AP 20. The display 35 is, for example, a liquid crystal display (LCD) or an electro-luminescence (EL) display. The display 35 displays, for example, a graphical user interface (GUI) corresponding to application software. The storage 36 is a non-volatile storage device and stores, for example, system software for the terminal device 30.

[0028] The terminal device 30 may have other hardware configurations. For example, if the terminal device 30 is an IoT (Internet of Things) terminal or the like, the display 35 may be omitted from the terminal device 30. The display 35 may function as an input interface for the terminal device 30. The antenna may be built into the terminal device 30 or may be externally connected.

[0029] <1-3> Functional Configuration of Information Communication System 1 The functional configuration of the information communication system 1 according to the embodiment will be described below.

[0030] <1-3-1> Functional Configuration of Sharing AP 10 FIG. 5 is a block diagram showing an example of the functional configuration of the sharing AP 10 included in the information communication system 1 according to the embodiment. As shown in FIG. 5, the sharing AP 10 functions as a computer including, for example, an LLC processing unit 110, a data processing unit 120, a management unit 130, a frame processing unit 140, and a transceiver unit 150. The LLC processing unit 110 is a functional block that executes processing corresponding to the LLC sublayer of layer 2 and layers 3 to 7. The data processing unit 120, the management unit 130, and the frame processing unit 140 are functional blocks that execute processing corresponding to the MAC sublayer of layer 2. The transceiver unit 150 is a functional block that executes processing corresponding to layer 1.

[0031] The LLC processing unit 110 generates LLC packets by, for example, adding a DSAP (Destination Service Access Point) header or an SSAP (Destination Service Access Point) header to data received from the network NW. The LLC processing unit 110 then inputs the generated LLC packets to the data processing unit 120. The LLC processing unit 110 also extracts data from the LLC packets input from the data processing unit 120. The LLC processing unit 110 then transmits the extracted data to the network NW.

[0032] Data processing unit 120 generates a MAC frame by adding a MAC header to the LLC packet input from LLC processing unit 110. Data processing unit 120 then inputs the generated MAC frame to frame processing unit 140. Data processing unit 120 also extracts LLC packets from the MAC frame input from frame processing unit 140. Data processing unit 120 then inputs the extracted LLC packets to LLC processing unit 110. A MAC frame containing data is also called a "data frame."

[0033] The management unit 130 establishes a wireless connection (wireless link) with the non-AP_MLD of the terminal device 30, maps data types to links, sets up BlockAck, and so on. For example, the management unit 130 executes multi-AP association processing in response to a multi-AP association request from the terminal device 30. For example, if the terminal device 30 uses two APs, A-STA1 and A-STA2, the multi-AP association processing causes A-STA1 to establish a wireless link with the shared AP 20-1, and A-STA2 to establish a wireless link with the shared AP 20-2.

[0034] The management unit 130 also manages multi-AP management information 131 and link management information 132. The multi-AP management information 131 includes information about the access points used in the multi-AP connection (i.e., the sharing AP 10 and the shared APs 20-1 and 20-2) and the terminal device 30. For example, the multi-AP management information 131 is provided for each terminal device 30 that establishes a multi-AP connection. The link management information 132 includes information about the status of links established in the multi-AP connection.

[0035] When a MAC frame is input from the data processing unit 120 or the management unit 130, the frame processing unit 140 outputs the input MAC frame to the transceiver unit 150. Furthermore, when a MAC frame is input from the transceiver unit 150, the frame processing unit 140 outputs the input frame to the data processing unit 120 or the management unit 130 depending on the frame type. For example, when a data frame is input from the transceiver unit 150, the frame processing unit 140 outputs the input frame to the data processing unit 120. When a management frame or a control frame is input from the transceiver unit 150, the frame processing unit 140 outputs the input frame to the management unit 130. The management frame or the control frame includes, for example, management information. The management information may include notification information for either the shared AP 20 or the terminal device 30, control information related to control of the operation of either the shared AP 20 or the terminal device 30, and the like.

[0036] The transceiver 150 transmits and receives data, management information, and the like to and from each of the multiple shared APs 20 belonging to the sharing AP 10. The transceiver 150 is provided with, for example, one wireless signal processing unit for each of the multiple shared APs 20 belonging to the sharing AP 10. Each wireless signal processing unit of the transceiver 150 is configured to transmit and receive wireless signals using a different frequency band or channel.

[0037] Each wireless signal processing unit of the transceiver 150 generates a wireless frame by adding a preamble or the like to the MAC frame input from the frame processing unit 140, and converts the generated wireless frame into a wireless signal. Each wireless signal processing unit then transmits (radiates) the converted wireless signal via an antenna to the wirelessly connected shared AP 20. Each wireless signal processing unit of the transceiver 150 also converts a wireless signal received from one of the shared APs 20 via the antenna into a wireless frame. Each wireless signal processing unit then extracts a MAC frame from the converted wireless frame and outputs the extracted MAC frame to the frame processing unit 140. The transceiver 150 may use multicast or broadcast when simultaneously notifying multiple shared APs 20. Multicast and broadcast are used, for example, to transmit beacons and the like.

[0038] The multi-AP management information 131 may include information related to frequency bands, channels, operational parameters, access categories, etc. The frequency band information indicates, for example, the frequency band used by the A-STA for the wireless link. The channel information indicates, for example, the channel used by the A-STA for the wireless link. The operational parameter information includes, for example, CWmin, CWmax, AIFS (arbitration interframe space), and TXOP (transmission opportunity) Limit. CWmin and CWmax indicate the minimum and maximum values ​​of the contention window, respectively. The contention window is a parameter used to calculate backoff, which is a transmission waiting time for collision avoidance. AIFS is a fixed transmission waiting time set for each access category of traffic. TXOPLimit indicates the upper limit of the channel occupation period TXOP. The access category information is indicated by, for example, "VO (Voice)", "VI (Video)", "BE (Best Effort)", "BK (Background)", and "LL (Low Latency)".

[0039] The link management information 132 may include information indicating whether a wireless link is enabled or disabled. The multi-AP management information 131 and the link management information 132 may be integrated. Based on the multi-AP management information 131, the frame processing unit 140 may output data to be transmitted to the shared AP 20-1 to a wireless signal processing unit associated with the shared AP 20-1, and output data to be transmitted to the shared AP 20-2 to a wireless signal processing unit associated with the shared AP 20-2. The frame processing unit 140 may determine the destination of the MAC frame input from the data processing unit 120 based on a traffic identifier (TID) associated with an access category. This process of associating a TID with a link is also referred to as "TID-link mapping." The transceiver unit 150 may be provided with a wireless signal processing unit assigned to transmitting and receiving data, etc., as well as a wireless signal processing unit assigned to transmitting management information.

[0040] (Functional Configuration of Frame Processing Unit 140 of Sharing AP 10) Fig. 6 is a block diagram showing an example of the functional configuration of the frame processing unit 140 included in the sharing AP 10 provided in the information communication system 1 according to the embodiment. As shown in Fig. 6, the frame processing unit 140 includes a MAC frame generation unit 141, a transmission buffer control unit 142, a reception status management unit 143, and a sorting buffer unit 144.

[0041] When a bitmap is input from the reception status management unit 143, the MAC frame generation unit 141 generates a BlockAck including the input bitmap and outputs it to the transmission buffer control unit 142. When downstream data or the like is input from the data processing unit 120, the MAC frame generation unit 141 generates a MAC frame by adding a header or the like and outputs it to the transmission / reception unit 150. The MAC header included in the MAC frame includes a sequence number SN assigned to identify the data.

[0042] The transmission buffer control unit 142 outputs the MAC frame input from the MAC frame generation unit 141 to the transmission / reception unit 150. If the input MAC frame is downlink data, the transmission buffer control unit 142 associates a sequence number SN with the MAC frame, stores the MAC frame in the transmission buffer, and outputs the MAC frame to the transmission / reception unit 150. The transmission buffer control unit 142 can also notify the reception status management unit 143 of the sequence number SN of the data stored in the transmission buffer. The handling of data frames in the transmission buffer control unit 142 is the same as the handling of uplink data in non-AP_MLD.

[0043] If the MAC frame input from the transmitting / receiving unit 150 is from a shared AP 20 connected to the local station, the reception status management unit 143 determines whether the frame was received correctly based on the frame check sequence. The reception status management unit 143 then outputs the correctly received data to the sorting buffer unit 144. The reception status management unit 143 also generates or updates reception success / failure information that manages the results of reception success / failure for each sequence number SN based on the information about the sequence number SN notified by the transmission buffer control unit 142. The reception status management unit 143 then updates the reception success / failure information based on the results of reception success / failure. When the reception status management unit 143 receives a BlockAck request, it generates a bitmap based on the reception success / failure information and outputs it to the MAC frame generation unit 141.

[0044] The reordering buffer unit 144 accumulates MAC frames input from the reception status management unit 143. If the sequence numbers SN of the accumulated MAC frames are received in order without any missing numbers from the beginning, the reordering buffer unit 144 outputs the MAC frames that have been received in order to the data processing unit 120. For example, the reordering buffer unit 144 can control the receive window of the accumulated MAC frames (data) based on the start sequence number SSN included in a BlockAck sent from the terminal device 30. The receive window indicates the sequence number SN and reception status of data transferred from the terminal device 30 when the sharing AP 10 receives upstream traffic. In this case, the reordering buffer unit 144 outputs data with sequence numbers SN earlier than the start sequence number SSN included in the BlockAck to the upper layer and deletes (discards) the data output to the upper layer from the reordering buffer unit 144.

[0045] <1-3-2> Functional Configuration of the Shared AP 20 Fig. 7 is a block diagram showing an example of the functional configuration of the shared AP 20 included in the information communication system 1 according to the embodiment. As shown in Fig. 7, the shared AP 20 functions as a computer including, for example, transceiver units 210-1 and 210-2, a management unit 220, frame processing units 230-1 and 230-2, and a data processing unit 240. The transceiver units 210-1 and 210-2 are functional blocks that perform processing corresponding to the first layer. The management unit 220 and frame processing units 230-1 and 230-2 are functional blocks that perform processing corresponding to the MAC sublayer of the second layer.

[0046] The transceiver 210-1 transmits and receives data, management information, etc. to and from the sharing AP 10 via wireless communication. The transceiver 210-2 transmits and receives data, management information, etc. to and from the terminal device 30 via wireless communication. The transceivers 210-1 and 210-2 are associated with frame processors 230-1 and 230-2, respectively. Each of the transceivers 210-1 and 210-2 includes a wireless signal processor. Note that in the shared AP 20, the wireless signal processor of the transceiver 210-1 and the wireless signal processor of the transceiver 210-2 are preferably configured to use different frequency bands or channels.

[0047] The radio signal processing unit of the transceiver unit 210-1 generates a radio frame by adding a preamble or the like to the MAC frame (data frame, management frame, etc.) input from the frame processing unit 230-1. Then, the radio signal processing unit of the transceiver unit 210-1 converts the generated radio frame into a radio signal and transmits (radiates) the converted radio signal to the sharing AP 10 via the antenna. Furthermore, the radio signal processing unit of the transceiver unit 210-1 converts the radio signal received from the sharing AP 10 via the antenna into a radio frame. Then, the radio signal processing unit of the transceiver unit 210-1 extracts the MAC frame from the converted radio frame and outputs the extracted MAC frame to the frame processing unit 230-1.

[0048] The radio signal processing unit of the transceiver unit 210-2 generates a radio frame by adding a preamble or the like to the MAC frame (data frame, management frame, etc.) input from the frame processing unit 230-2. The radio signal processing unit of the transceiver unit 210-2 then converts the generated radio frame into a radio signal and transmits (radiates) the converted radio signal to the terminal device 30 via the antenna. The radio signal processing unit of the transceiver unit 210-2 also converts a radio signal received from the terminal device 30 via the antenna into a radio frame. The radio signal processing unit of the transceiver unit 210-2 extracts a MAC frame from the converted radio frame and outputs the extracted MAC frame to the frame processing unit 230-2.

[0049] The management unit 220 controls the establishment of a wireless connection (wireless link) between the sharing AP 10 in the multi-AP connection and the non-AP MLD of the terminal device 30. Furthermore, the management unit 220 generates and distributes beacons necessary for the multi-AP connection based on a notification from the sharing AP 10, and manages the state of the wireless link between the A-AP of the shared AP 20 in the multi-AP connection and the A-STA of the terminal device 30. Furthermore, the management unit 220 includes link management information 221 and a beacon generation unit 222.

[0050] The link management information 221 stores management information related to the status of wireless links used in a multi-AP connection. The link management information 221 also includes, for example, an identifier of the sharing AP 10 to which the local station belongs and an identifier of the A-STA of the terminal device 30 that has established a wireless link with the local station. The link management information 221 may store information included in the multi-AP management information 131 and the link management information 132. The management unit 220 uses the link management information 221 to manage whether wireless links are enabled or disabled.

[0051] The beacon generation unit 222 generates a beacon frame or the like including information related to the multi-AP connection based on the management information received from the sharing AP 10. The beacon generation unit 222 notifies the terminal device 30 of the generated beacon frame via the frame processing unit 230-1 and the transmission / reception unit 210-1. The beacon frame includes, for example, information about the sharing AP 10, information about the shared AP 20 of the own station, and information about the shared AP 20 of the other station included in the multi-AP connection. The beacon frame may include the multi-AP management information 131 and the link management information 132 transferred from the sharing AP 10. The beacon frame may be transmitted by broadcast or multicast.

[0052] When a MAC frame is input from the data processing unit 240, the frame processing unit 230-1 outputs the input frame to the transceiver unit 210-1. When a MAC frame is input from the transceiver unit 210-1, the frame processing unit 230-1 outputs the input MAC frame to the management unit 220 or the data processing unit 240, depending on the frame type. For example, when a data frame is input from the transceiver unit 210-1, the frame processing unit 230-1 outputs the input frame to the data processing unit 240. When a management frame or control frame intended for the frame processing unit 230-1 is input from the transceiver unit 210-1, the frame processing unit 230-1 outputs the input frame to the management unit 220.

[0053] When a MAC frame is input from the data processing unit 240, the frame processing unit 230-2 outputs the input frame to the transceiver unit 210-2. When a MAC frame is input from the transceiver unit 210-2, the frame processing unit 230-2 outputs the input MAC frame to the management unit 220 or the data processing unit 240, depending on the frame type. For example, when a data frame is input from the transceiver unit 210-2, the frame processing unit 230-2 outputs the input frame to the data processing unit 240. When a management frame or control frame intended for the frame processing unit 230-2 is input from the transceiver unit 210-2, the frame processing unit 230-2 outputs the input frame to the management unit 220.

[0054] Data processing unit 240 outputs the MAC frame input from frame processing unit 230-1 to frame processing unit 230-2, and also outputs the MAC frame input from frame processing unit 230-2 to frame processing unit 230-1.

[0055] (Functional Configuration of Frame Processing Units 230-1 and 230-2 of Shared AP 20) Fig. 8 is a block diagram showing an example of the functional configuration of frame processing units 230-1 and 230-2 included in the shared AP 20 provided in the information communication system 1 according to the embodiment. As shown in Fig. 8, the frame processing unit 230-1 includes a transmission buffer control unit 231-1, a reception status management unit 232-1, and a sorting buffer unit 233-1. The frame processing unit 230-2 includes a transmission buffer control unit 231-2, a reception status management unit 232-2, and a sorting buffer unit 233-2. In each of the frame processing units 230-1 and 230-2, the functional blocks used change depending on the transmission direction of the frame.

[0056] First, the functional configuration of the frame processing units 230-1 and 230-2 used when transferring traffic from the terminal device 30 to the sharing AP 10, that is, when the shared AP 20 transfers upstream traffic, will be described.

[0057] If the MAC frame input from the transceiver unit 210-2 is from an A-STA connected to the own station, the reception status management unit 232-2 determines whether the frame was received correctly based on the frame check sequence, and outputs the correctly received data to the sorting buffer unit 233-2.

[0058] The reordering buffer unit 233-2 accumulates the MAC frames input from the reception status management unit 232-2. The reordering buffer unit 233 then outputs the accumulated MAC frames to the transmission buffer control unit 231-1 via the data processing unit 240 in the order of their sequence numbers SN.

[0059] The transmission buffer control unit 231-1 accumulates MAC frames input from the data processing unit 240 in a transmission buffer, extracts the MAC frames based on window control (described later), and outputs them to the transmission / reception unit 210-1. The transmission buffer control unit 231-1 can also generate a BlockAck request and output it to the transmission / reception unit 210-1.

[0060] When the reception status management unit 232-1 receives BlockAck from the sharing AP 10, it outputs the bitmap included in the BlockAck to the transmission buffer control unit 231-1. Based on the bitmap input from the reception status management unit 232-1, the transmission buffer control unit 231-1 can retrieve from the transmission buffer and retransmit the MAC frame that the sharing AP 10 failed to receive.

[0061] Next, the functional configuration of the frame processing units 230-1 and 230-2 used when transferring traffic from the sharing AP 10 to the terminal device 30, that is, when the shared AP 20 transfers downstream traffic, will be described.

[0062] If the MAC frame input from the transmitting / receiving unit 210-1 is from a sharing AP 10 connected to the receiving station, the receiving status management unit 232-1 determines whether the frame has been received correctly based on the frame check sequence, and outputs the correctly received data to the sorting buffer unit 233-1.

[0063] The reordering buffer unit 233-1 accumulates the MAC frames input from the reception status management unit 232-1. The reordering buffer unit 233-1 then outputs the accumulated MAC frames to the transmission buffer control unit 231-2 via the data processing unit 240 in the order of their sequence numbers SN.

[0064] The transmission buffer control unit 231-2 accumulates MAC frames input from the data processing unit 240 in a transmission buffer, extracts the MAC frames based on window control (described later), and outputs them to the transmission / reception unit 210-2. The transmission buffer control unit 231-2 can also generate a BlockAck request and output it to the transmission / reception unit 210-2.

[0065] The reception status management unit 232-2 outputs the bitmap included in the BlockAck to the transmission buffer control unit 231-2 when it receives BlockAck from the A-STA of the terminal device 30. Based on the bitmap input from the reception status management unit 232-2, the transmission buffer control unit 231-2 can retrieve from the transmission buffer and retransmit the MAC frame that was unsuccessfully received by the A-STA of the terminal device 30.

[0066] <1-3-3> Functional Configuration of Terminal Device 30 FIG. 9 is a block diagram showing an example of the functional configuration of the terminal device 30 included in the information communication system 1 according to the embodiment. As shown in FIG. 9, the terminal device 30 functions as a computer including an application execution unit 300, an LLC processing unit 310, a data processing unit 320, a management unit 330, a frame processing unit 340, and A-STA1 and A-STA2. The application execution unit 300 is a functional block that executes processing corresponding to layer 7. The LLC processing unit 310 is a functional block that executes processing corresponding to the LLC sublayer of layer 2 and layers 3 to 6. The data processing unit 320, the management unit 330, and the frame processing unit 340 are functional blocks that execute processing corresponding to the MAC sublayer of layer 2. A-STA1 and A-STA2 are functional blocks that execute processing corresponding to the MAC sublayer of layer 2 and layer 1. For example, a set of the LLC processing unit 310, the data processing unit 320, the management unit 330, and the frame processing unit 340 corresponds to non-AP_MLD.

[0067] The application execution unit 300 executes an application based on data input from the LLC processing unit 310. The application execution unit 300 also outputs data to the LLC processing unit 310. For example, the application execution unit 300 can display application information on the display 35. The application execution unit 300 can also operate based on operations on an input interface.

[0068] The LLC processing unit 310 generates LLC packets by adding DSAP headers, SSAP headers, etc. to data input from the application execution unit 300 (upper layer). The LLC processing unit 310 then outputs the generated LLC packets to the data processing unit 320. The LLC processing unit 310 also extracts data from the LLC packets input from the data processing unit 320. The LLC processing unit 310 then outputs the extracted data to the application execution unit 300 (upper layer).

[0069] The data processing unit 320 generates a MAC frame by adding a MAC header to the LLC packet input from the LLC processing unit 310. The data processing unit 320 then outputs the generated MAC frame to the frame processing unit 340. The data processing unit 320 also extracts an LLC packet from the MAC frame input from the frame processing unit 340. The data processing unit 320 then outputs the extracted LLC packet to the LLC processing unit 310.

[0070] The management unit 330 establishes a wireless connection (wireless link) with the sharing AP 10, maps data types to links, sets up BlockAck, and so on. The management unit 330 can acquire management information from, for example, a beacon received from the shared AP 20. The management unit 330 also manages the status of the wireless link between the A-AP of the shared AP 20 and the A-STA of the terminal device 30 in a multi-AP connection. The management unit 330 also includes link management information 331.

[0071] The link management information 331 stores management information related to the status of wireless links used in a multi-AP connection. The link management information 331 also includes, for example, information related to the identifier of the sharing AP 10 to which the local station belongs and the identifier of the shared AP 20 that has established a wireless link with the local station. The link management information 331 may store information included in the multi-AP management information 131 and the link management information 132. The management unit 330 uses the link management information 331 to manage whether wireless links are enabled or disabled.

[0072] When a MAC frame is input from the data processing unit 320, the frame processing unit 340 outputs the input frame to at least one of A-STA1 and A-STA2 in accordance with traffic allocation. Furthermore, when a MAC frame is input from either A-STA1 or A-STA2, the frame processing unit 340 outputs the input frame to the management unit 330 or the data processing unit 320 in accordance with the frame type. For example, when a data frame is input from either A-STA1 or A-STA2, the frame processing unit 340 outputs the input frame to the data processing unit 320. When a data frame is input from the data processing unit 320, the frame processing unit 340 outputs the input frame to either A-STA1 or A-STA2. When a management frame or control frame intended for the own station is input from either A-STA1 or A-STA2, the frame processing unit 340 outputs the input frame to the management unit 330.

[0073] Each of A-STA1 and A-STA2 functions as a wireless signal processing unit configured to be able to transmit and receive data, management information, and the like to and from the shared AP 20 via wireless communication. The A-STA generates a wireless frame by adding a preamble, etc., to the MAC frame input from the frame processing unit 340. The A-STA then converts the generated wireless frame into a wireless signal. The A-STA then transmits (radiates) the converted wireless signal via an antenna to the wirelessly connected shared AP 20. The A-STA also converts a wireless signal received from the wirelessly connected shared AP 20 via an antenna into a wireless frame. The A-STA extracts a MAC frame from the converted wireless frame and outputs the extracted MAC frame to the frame processing unit 340.

[0074] 10 is a block diagram showing an example of the functional configuration of the frame processing unit 340 included in the terminal device 30 provided in the information communication system 1 according to the embodiment. As shown in FIG. 10, the frame processing unit 340 includes a transmission buffer control unit 341, a reception status management unit 342, and a sorting buffer unit 343.

[0075] The transmission buffer control unit 341 associates a sequence number SN with the data input from the data processing unit 320, stores the data in the transmission buffer, extracts the MAC frame based on window control (described later), and outputs the frame to one of the A-STAs. The window is set based on a bitmap included in the BlockAck (BA) input from the reception status management unit 342. The data allocation by the transmission buffer control unit 341 may be to send the data to an A-STA corresponding to the traffic type (TID) based on TID-link mapping.

[0076] The transmission buffer control unit 341 can also notify the reception status management unit 342 of the sequence number SN of the data stored in the transmission buffer. The transmission buffer control unit 341 can generate a BlockAck request (BAR) for triggering a reception confirmation, and output it to one of the A-STAs. The BlockAck request generated by the transmission buffer control unit 341 includes a start sequence number SSN. The BlockAck includes the start sequence number SSN and a bitmap (reception success / failure information for each sequence number SN, starting with the start sequence number SSN).

[0077] If the MAC frame input from the A-STA is from the shared AP 20 connected to the A-STA, the reception status management unit 342 determines whether the frame was received correctly based on the frame check sequence.The reception status management unit 342 then outputs the correctly received data to the sorting buffer unit 343.The reception status management unit 342 also generates or updates reception success / failure information that manages the results of reception success / failure for each sequence number SN based on the information of the sequence number SN notified by the transmission buffer control unit 341.The reception status management unit 342 then updates the reception success / failure information based on the results of reception success / failure.When the reception status management unit 342 receives a BlockAck request, it generates a bitmap based on the reception success / failure information and outputs it to the transmission buffer control unit 341.

[0078] The reordering buffer unit 343 accumulates MAC frames input from the reception status management unit 342. If the sequence numbers SN of the accumulated MAC frames are received in order without any missing numbers from the beginning, the reordering buffer unit 343 outputs the MAC frames that have been received in order to the data processing unit 320. For example, the reordering buffer unit 343 can control the receive window of the accumulated MAC frames (data) based on the start sequence number SSN included in a BlockAck sent from the sharing AP 10. The receive window indicates the sequence number SN and reception status of data transferred from the sharing AP 10 when the terminal device 30 receives downstream traffic. In this case, the reordering buffer unit 344 outputs data with sequence numbers SN earlier than the start sequence number SSN included in the BlockAck to the upper layer and deletes (discards) the data output to the upper layer from the reordering buffer unit 343.

[0079] 11 is a block diagram showing an example of the functional configuration of an affiliated STA (A-STA) included in the terminal device 30 provided in the information communication system 1 according to the embodiment. As shown in FIG. 11, the A-STA includes a MAC frame generation unit 351, a transmission / reception unit 352, and a MAC frame processing unit 353.

[0080] The MAC frame generation unit 351 generates a MAC frame by adding a MAC header and the like to the data and the like input from the transmission buffer control unit 341, and outputs the MAC frame to the transmission / reception unit 352. The MAC header includes a sequence number SN assigned to identify the data. In other words, the sequence number SN is output from the non-AP_MLD transmission buffer together with the data.

[0081] The transmitting / receiving unit 352 performs wireless processing on and transmits the MAC frame input from the MAC frame generating unit 351. On the other hand, the transmitting / receiving unit 352 extracts a MAC frame from a wireless signal received via an antenna and outputs the MAC frame to the MAC frame processing unit 353.

[0082] The MAC frame processing unit 353 determines whether the MAC frame input from the transmitting / receiving unit 352 has been correctly received based on the frame check sequence. Then, the MAC frame processing unit 353 outputs the correctly received data to the non-AP_MLD frame processing unit 340.

[0083] <2> Operation Next, the operation of the information communication system 1 according to the embodiment will be described.

[0084] <2-1> MAC Sublayer Architecture FIG. 12 is a schematic diagram illustrating an example of a MAC sublayer architecture in the information communication system 1 according to the embodiment. The left side of FIG. 12 illustrates an example of a MAC sublayer architecture in the transmitting device (transmitting station TX) of the sharing AP 10 and the terminal device 30. The right side of FIG. 12 illustrates an example of a MAC sublayer architecture in the receiving device (receiving station RX) of the sharing AP 10 and the terminal device 30. The transmitting station TX corresponds to the terminal device 30 when transmitting upstream traffic, for example, and corresponds to the sharing AP 10 when transmitting downstream traffic. The receiving station RX corresponds to the sharing AP 10 when transmitting upstream traffic, for example, and corresponds to the terminal device 30 when transmitting downstream traffic. Note that the MAC sublayer architecture illustrated in FIG. 12 is merely an example. In a multi-AP connection, the MAC sublayer may be divided into an upper MAC sublayer that includes processing commonly executed across multiple links, and a lower MAC sublayer that includes processing executed for each of the multiple links. (Processing of Transmitting Station TX) As shown on the left side of Fig. 12, after completing LLC layer processing for data to be transmitted, the transmitting station TX sequentially executes processes S10 to S15 in the MAC layer. The processes described below can be executed by the frame processing unit 140, 340, etc.

[0085] First, A-MSDU aggregation is performed (S10). A-MSDU aggregation is a process of combining multiple MSDUs (MAC Service Data Units) input from the LLC layer to create a single A-MSDU. An MSDU is a unit of data handled in the LLC layer. If multiple MSDUs have the same receiving station address and the same TID, the transmitting station TX can create an A-MSDU using the multiple MSDUs.

[0086] Next, one sequence number SN is assigned to one A-MSDU (S11). The transmitting station TX may manage the sequence number SN for each TID, or may manage it collectively for multiple TIDs. The sequence number SN is used to identify the part of the data that the receiving station RX has successfully received.

[0087] Next, fragmentation is performed on one A-MSDU (S12). Fragmentation is a process of fragmenting (dividing) an A-MSDU. Each fragmented A-MSDU corresponds to an MPDU.

[0088] Next, MPDU encryption is performed on each MPDU (S13). MPDU encryption is a process of encrypting an MPDU. The encrypted MPDU is configured to be decryptable among the sharing AP 10, the shared AP 20, and the terminal device 30, for which association has been established.

[0089] Next, a MAC header and an error detection code are added to the encrypted MPDU (S14). The MAC header includes MAC addresses of the destination and source, an Ethertype field, etc. The error detection code is used to detect errors in the data received by the receiving station RX. For example, a CRC (Cyclic Redundancy Check) is used as the error detection code.

[0090] Next, A-MPDU aggregation is performed (S15). A-MPDU aggregation is a process of combining multiple MPDUs to generate one A-MPDU. The generated A-MPDU is input to the physical layer.

[0091] The transmitting station TX can control the buffer using BlockAck. For example, the transmitting station TX deletes data whose reception has been confirmed from the transmission buffer, and performs window control for transmitting the next data. The window control includes a process of shifting the transmission window from the beginning to the point where delivery confirmation has been confirmed.

[0092] (Processing by Receiving Station RX) As shown on the right side of Fig. 12, after completing physical layer processing for the received wireless signal, the receiving station RX sequentially executes processes S20 to S26 in the MAC layer. The processes described below may be executed by the frame processing unit 140, 340, etc.

[0093] First, A-MPDU deaggregation is executed (S20). A-MPDU deaggregation is a process of deaggregating (dividing) A-MPDUs input from the physical layer into MPDU units.

[0094] Next, error detection is performed (S21). Error detection is a process of detecting errors in the received data using an error detection code (for example, CRC). The error detection in step S21 is performed for each MPDU.

[0095] Next, the reception status is checked (S22). Specifically, the success or failure of reception of the data (MPDU) is determined based on the success or failure of error detection. If no error is detected, i.e., if the data has been successfully received, the receiving station RX executes the next process using the data. On the other hand, if an error is detected, the receiving station RX discards the data in which the error was detected. Furthermore, the receiving station RX updates the reception success or failure information based on the reception result and the data reception status. Furthermore, in response to receiving the BlockAck request, the receiving station RX transmits a BlockAck including a bitmap containing at least a part of the reception success or failure information to the transmitting station TX using the wireless link over which the BlockAck request was received.

[0096] Next, MPDU decoding is performed (S23). MPDU decoding is a process of decrypting the encrypted MPDU. MPDU decoding is successful if the MPDU is data communicated between devices that have established association in a multi-AP connection.

[0097] Next, the decoded MPDUs are reordered (S24). The reordering process is a process of reordering the MPDUs that have been successfully received in order of their sequence numbers SN.

[0098] Next, the rearranged MPDU is defragmented (S25). Defragmentation is a process of combining multiple MPDUs to restore an A-MSDU.

[0099] Next, A-MSDU deaggregation is performed (S26). A-MSDU deaggregation is a process of dividing the restored A-MSDU into MSDU units. The divided A-MSDUs are input to the LLC layer.

[0100] (Configuration of the Transmission Buffer of the Transmitting Station TX) FIG. 13 is a table showing an example of the configuration of the transmission buffer of the transmitting station TX in the information communication system 1 according to the embodiment. As shown in FIG. 13, the transmission buffer stores data for each sequence number SN. In this example, data D1 to D6 are associated with sequence numbers SN#1 to SN#6, respectively. In addition, the transmission buffer control unit 142 or 341 manages information indicating the reception status of each sequence number SN as reception success / failure information associated with the transmission buffer. FIG. 13 shows a case where data D3 associated with sequence number SN3 has not been received, and data D associated with other sequence numbers SN has been successfully received.

[0101] Furthermore, a transmission window TW is set in each of the transmission buffer control units 142 and 341 as a unit for attempting to transmit data. The transmission window TW indicates the range of sequence numbers SN for which transmission is attempted. The transmission window TW can be specified, for example, by a window start and a window size (the number of frames of sequence numbers SN for which transmission is attempted starting from the window start). Hereinafter, the last sequence number SN included in the transmission window TW indicated by the window start and window size is also referred to as the "window end."

[0102] <2-2> Multi-AP Connection Setup Method Fig. 14 is a time chart showing an example of a multi-AP connection setup sequence in the information communication system 1 according to the embodiment. An example of the multi-AP connection setup sequence will be described below with reference to Fig. 14. Note that the shared AP 20-2 and A-STA 2 are not shown in Fig. 14.

[0103] First, the sharing AP 10 notifies each shared AP of multi-AP management information by multicast or broadcast. The multi-AP management information includes, for example, the identifiers of the sharing AP 10 and the shared AP 20 used for the multi-AP connection. Then, upon receiving the multi-AP management information, each shared AP 20 broadcasts the information in a beacon frame. Each A-STA receives the beacon frame and outputs it to the non-AP_MLD. The non-AP_MLD acquires the multi-AP management information from the input beacon frame. Then, based on the multi-AP management information, the non-AP_MLD generates a multi-AP association request including the identifier of the destination sharing AP and the identifiers of each shared AP, and transmits the request to the sharing AP 10 via one of the A-STAs and the shared AP 20.

[0104] Based on the multi-AP association request, the sharing AP 10 outputs an association notification (or request) to the subordinate shared APs 20 by multicast. Then, based on the response from the shared AP 20 that is the target of the multi-AP connection, the sharing AP 10 transmits a multi-AP association response to the non-AP_MLD. If each shared AP 20 is included in the association notification from the sharing AP 10, it returns a response to the notification. Based on the response from the sharing AP 10, the non-AP_MLD sends an association notification to each A-STA. This establishes a wireless connection between the associated A-STA and the shared AP 20.

[0105] Next, the sharing AP 10 performs TID-link mapping. Specifically, the sharing AP 10 sends a TID-link mapping request to the non-AP_MLD. Then, the non-AP_MLD returns a response to the TID-link mapping request (TID-link mapping response) to the sharing AP 10. This allows the sharing AP 10 to associate each TID with a link (in this example, corresponding to the shared AP 20) with the non-AP_MLD. In the default setting, for example, each TID is associated with all links. If the sharing AP 10 wishes to associate only a specific link with a specific TID, it associates the target link with that TID using TID-link mapping.

[0106] Next, the sharing AP 10 performs BlockAck setup. Specifically, before exchanging BlockAck, the sharing AP 10 sends an ADDBA request to the non-AP_MLD. The ADDED request includes the target TID, buffer size, initial value of the start sequence number (SSN), and so on. The non-AP_MLD then returns a response to the ADDBA request (ADDBA response) to the sharing AP 10. This allows the sharing AP 10 to set up the implementation parameters for BlockAck during data transfer.

[0107] As described above, in the information communication system 1, the management unit 130 may cooperate with the multiple shared APs 20 belonging to the sharing AP 10 and the non-AP MLD of the terminal device 30 to allocate (map) traffic transmitted and received between the sharing AP 10 and the terminal device 30. As a result, the management unit 130 can instruct the frame processing unit 140 on the destination of the traffic based on the traffic allocation. The frame processing unit 140 can then cause the transceiver unit 150 to transmit traffic to the shared AP 20 based on the instruction from the management unit 130. For example, traffic allocated to a link associated with shared AP 20-1 is transmitted from the transceiver unit 150 of the sharing AP 10 to the shared AP 20-1 based on the instruction from the management unit 130.

[0108] <2-3> Data Transfer Method FIG. 15 is a block diagram showing an example of a data transfer method in an information communication system according to an embodiment. FIG. 15 illustrates an example in which uplink traffic is transferred from a terminal device 30 to a sharing AP 10 using a multi-AP connection. In this example, A-STA1 is assigned to transfer data with odd sequence numbers SN. A-STA2 is assigned to transfer data with even sequence numbers SN. In other words, the example illustrates a case in which data with the same TID is mapped to A-STA1 and A-STA2, and the transmission buffer control unit 341 alternately distributes data between A-STA1 and A-STA2. Furthermore, in the specific example of the data transfer method described below, a case in which uplink traffic assigned sequence numbers SN: #1 to #12 occurs will be described.

[0109] BlockAck in the information communication system 1 according to the first embodiment is executed in two stages: (1) end-to-end (between the sharing AP 10 and the non-AP_MLD), and (2) for each link. (1) The non-AP_MLD sends a BlockAck request to the sharing AP 10 and acquires the reception status for all sequence numbers SN. (2) Each shared AP 20 also sends a BlockAck request to the sharing AP 10 and acquires the reception status for all sequence numbers SN. (1) and (2) Upon receiving a BlockAck request, the sharing AP 10 replies with the reception status for all sequence numbers SN using BlockAck.

[0110] In the information communication system 1 according to the first embodiment, the non-AP_MLD shifts the window based on the acquired reception status. Specifically, the non-AP_MLD shifts the sequence numbers SN for which reception has been confirmed, starting from the top. The non-AP_MLD then deletes (discards) from the transmission buffer any data that falls outside the window due to the window shift, and sets the data that has now fallen within the window range due to the window shift as the next data to be transmitted.

[0111] Furthermore, in the information communication system 1 according to the first embodiment, each device performs window control of its transmission buffer and reception success / failure information based on the starting sequence number SSN included in the BlockAck request on the sending side, so that each device performs autonomous and decentralized control so that the transmission buffer and reception success / failure information are consistent throughout the entire system. For example, each shared AP 20 controls its window so that if there is any sequence number SN for which delivery has not been confirmed by the sharing AP 10, regardless of whether or not the shared AP 20 has transmitted / buffered data, the shared AP 20 stops the window just before that sequence number. Specifically, the shared AP 20 shifts the window just before the starting sequence number SSN included in the BlockAck received from the sharing AP 10.

[0112] 16 is a flowchart showing an example of a window control method of the sharing AP 10 included in the information communication system 1 according to the embodiment. Hereinafter, with reference to FIG. 16, an example of the window control method of the sharing AP 10 will be described.

[0113] In the sharing AP 10, when the terminal device 30 is transmitting uplink data, the series of processes in FIG. 16 are appropriately executed (started).

[0114] First, the sharing AP 10 receives a BlockAck request (BAR) (S30). The source of the BlockAck received by the sharing AP 10 may be either the non-AP_MLD or the shared AP 20.

[0115] The sharing AP 10 then checks whether the sender of the BlockAck request is a non-AP_MLD (S31). If it is confirmed that the sender is a non-AP_MLD (S31: YES), the sharing AP 10 proceeds to the processing of S32. If it is confirmed that the sender is not a non-AP_MLD (S31: NO), the sharing AP 10 proceeds to the processing of S33. In this way, the processing to be executed next by the sharing AP 10 branches depending on the sender of the BlockAck.

[0116] In the process of S32, the sharing AP 10 updates the window. Specifically, the Window Start in the sorting buffer unit 144 is set to the start sequence number SSN in the BlockAck request (Window Start = SSN). In other words, in the process of S32, if the sender of the BlockAck request is non-AP_MLD, the sharing AP 10 shifts the reception confirmation window in the sharing AP 10 because the sending device (transmitting station) has also confirmed that reception of the data up to the start sequence number SSN has been completed. When the process of S32 is completed, the sharing AP 10 proceeds to the process of S33.

[0117] In the process of S33, the sharing AP 10 generates and transmits a BlockAck. Specifically, the sharing AP 10 first generates a BlockAck that includes an SSN and a bitmap. The sharing AP 10 sets the SSN to be stored in the BlockAck to the same value as the Window Start in the sorting buffer unit 144 (SSN = Window Start). Furthermore, based on the reception success / failure information from the reception status management unit 143, the sharing AP 10 sets the reception status corresponding to each sequence number SN in the bitmap stored in the BlockAck, starting from the starting sequence number SSN, to 0 (not received) or 1 (received). The sharing AP 10 then transmits the generated BlockAck to the device (the sharing AP 10 or the shared AP 20) that sent the BlockAck request. When the process of S33 is completed, the sharing AP 10 ends the series of processes in FIG. 16 (END).

[0118] 17 is a flowchart showing an example of a window control method for the shared AP 20 included in the information communication system 1 according to the embodiment. Hereinafter, with reference to FIG. 17, an example of the window control method for the shared AP 20 will be described.

[0119] In the shared AP 20, when the terminal device 30 is transmitting uplink data, the series of processes in FIG. 17 are appropriately executed (started).

[0120] First, the shared AP 20 receives a BlockAck (S30). The shared AP 20 then acquires the start sequence number (SSN) and bitmap from the received BlockAck. The shared AP 20 then updates the reception success / failure information in the reception status management unit 232 based on the contents of the received BlockAck.

[0121] Specifically, the shared AP 20 checks whether the start sequence number SSN indicated by the BlockAck is greater than the Window Start set in its own transmission buffer control unit 231 (S41: SSN>Window Start?). If SSN>Window Start (S41: YES), the shared AP 20 proceeds to processing S42. If SSN>Window Start is not true (S41: NO), the shared AP 20 proceeds to processing S42.

[0122] In the process of S42, the shared AP 20 updates the window. Specifically, the Window Start in the transmission buffer is set to the start sequence number SSN in the BlockAck (Window Start = SSN). In other words, in the process of S42, the shared AP 20 shifts the reception confirmation window in the shared AP 20 because the transmitting device (transmitting station) has confirmed that the data up to the start sequence number SSN has been received. When the process of S42 is completed, the shared AP 20 proceeds to the process of S42.

[0123] In the process of S43, the shared AP 20 updates the reception success / failure information. Specifically, the shared AP 20 updates the reception status corresponding to each sequence number SN based on 0 (not received) / 1 (received) in the bitmap included in the BlockAck. More specifically, the shared AP 20 sets the reception status to "1" for sequence numbers SN that are set to "1" in the bitmap, starting from the Window Start of the transmission buffer. Note that the shared AP 20 maintains the reception status at "0" for sequence numbers SN that are set to "0" in the bitmap. When the process of S43 is completed, the shared AP 20 proceeds to the process of S44.

[0124] In the process of S44, the shared AP 20 extracts sequence numbers SN included in the window start to window end of the transmission buffer that have a reception status of "0" and contain data stored in the transmission buffer, and transmits these to the sharing AP 10. When the process of S44 is completed, the shared AP 20 ends the series of processes in FIG. 17 (END).

[0125] 18 is a schematic diagram showing a specific example of a method for managing the transmission buffer of the shared AP 20 included in the information communication system 1 according to the embodiment. (A) of FIG. 18 shows data accumulated in the transmission buffer of the shared AP 20-1. (B) of FIG. 18 shows data accumulated in the transmission buffer of the shared AP 20-2. In this example, Window Start = 1 and Window Size = 6 are set for each of the shared APs 20-1 and 20-2.

[0126] 18, the transmission buffer of shared AP 20-1 stores data D1, D3, and D5 corresponding to odd sequence numbers SN#1, #3, and #5, respectively, and does not hold data (null) corresponding to even sequence numbers SN#2, #4, and #6. On the other hand, the transmission buffer of shared AP 20-2 stores data D2, D4, and D6 corresponding to even sequence numbers SN#2, #4, and #6, respectively, and does not hold data (null) corresponding to odd sequence numbers SN#1, #3, and #5.

[0127] Furthermore, in each of the shared APs 20-1 and 20-2, a transmission window TW is set based on Window Start = 1 and window size = 6. In this way, in the information communication system 1 according to the embodiment, the transmission buffer of each shared AP 20 is controlled so that the settings of the transmission windows TW of the shared APs 20-1 and 20-2 used in the multi-AP connection are synchronized.

[0128] 19 is a flowchart showing an example of a window control method of the terminal device 30 included in the information communication system 1 according to the embodiment. Hereinafter, with reference to FIG. 19, an example of the window control method of the terminal device 30 will be described.

[0129] When transmitting uplink data, the terminal device 30 appropriately executes (starts) the series of processes shown in FIG.

[0130] First, the terminal device 30 transmits a BlockAck request in which Window Start is stored in the start sequence number SSN to the sharing AP 10 that is the data recipient (S50).

[0131] Thereafter, the terminal device 30 receives a BlockAck in response to the transmitted BlockAck request (S51). The BlockAck contains a bitmap (in which the reception status for each sequence number SN is expressed as 0 / 1) starting from the Window Start at the receiving end as the starting sequence number SSN.

[0132] Then, the terminal device 30 updates the reception success / failure information based on the bitmap included in the BlockAck (S52). Specifically, the terminal device 30 sets the reception status to "1" for sequence numbers SN set to "1" in the bitmap, starting from Window Start. Note that the terminal device 30 maintains the reception status at "0" for sequence numbers SN set to "0" in the bitmap.

[0133] Then, the terminal device 30 updates the window (S53). Specifically, the terminal device 30 sets the Window Start of the transmission buffer to the sequence number SN next to the last sequence number SN that was successfully received in succession from the start sequence number SSN. The reason for this is that data set to "1" on the bitmap starting from the start sequence number SSN has been confirmed as received. The terminal device 30 also sets the Window End of the transmission buffer to a value obtained by adding the window size to the start sequence number SSN (Window End = SSN + Window Size). This allows the terminal device 30 to shift the transmission window TW by the amount of the consecutive "1s" set starting from the start sequence number SSN.

[0134] Next, the terminal device 30 extracts data with a reception status of "0" from the sequence numbers SN included in the window start to window end of the transmission buffer and transmits it to the sharing AP 10 (S54). In other words, by shifting the window in the processing of S53, the terminal device 30 can now see new data that can be transmitted, and so transmits this data. In the processing of S54, the terminal device 30 can also retransmit data for which reception could not be confirmed (data whose reception status is "0" on the bitmap and which has been accumulated in the transmission buffer).

[0135] <2-4> Specific Example of Data Transfer Sequence Figures 20A and 20B are time charts showing a specific example of a data transfer sequence in the information communication system 1 according to the embodiment. Figure 20B shows the processing following the time chart shown in Figure 20A. Note that in Figures 20A and 20B, the transmission buffers TB of the non-AP_MLD and the shared APs 20-1 and 20-2, and the sorting buffer unit 144 of the sharing AP 10 are assumed to store data with sequence numbers SN indicated by the numbers within the dashed lines. Furthermore, the numbers in the reception status RS written below the bitmaps of the transmission buffer TB and the sorting buffer unit 144 indicate the reception status of adjacent sequence numbers SN. Below, a specific example of a data transfer sequence when transferring upstream traffic will be described with reference to Figures 20A and 20B. In the following explanation, the timing at which the BlockAck requests are sent may be arbitrary, but to make the flow of control easier to understand, it is assumed that the requests are sent in the order of shared AP 20-1, shared AP 20-2, and non-AP_MLD.

[0136] At the start of the processing shown in FIG. 20A, data with sequence numbers SN #1 to #12 is stored in the transmission buffer of the terminal device 30 (non-AP_MLD). That is, there are 12 pieces of data stored in the transmission buffer of the non-AP_MLD, each assigned a sequence number from #1 to #12. Then, upstream traffic is transmitted from the non-AP_MLD to the sharing AP 10. Specifically, the non-AP_MLD outputs data D1, D3, and D5 with odd sequence numbers SN #1, #3, and #5 to A-STA1, and outputs data D2, D4, and D6 with even sequence numbers SN #2, #4, and #6 to A-STA2. Then, A-STA1 transmits data D1, D3, and D5 to the shared AP 20-1, and A-STA2 transmits data D2, D4, and D6 to the shared AP 20-2.

[0137] The shared AP 20-1 accumulates the received data D1, D3, and D5 in the transmission buffer TB, updates its own reception success / failure information, and transmits the data D1, D3, and D5 to the sharing AP 10. Then, the sharing AP 10 updates its own reception success / failure information (sorting buffer unit 144) based on the fact that it successfully received data D1 and failed to receive data D3 and D5. Thereafter, the shared AP 20-1 checks the reception status after data transmission by transmitting a BlockAck request to the sharing AP 10. In this example, the sharing AP 10 transmits a BlockAck (SSN=1, "100000") to the shared AP 20-1 as a response to the BAR. This "100000" corresponds to a bitmap indicating the reception status, starting from the associated start sequence number SSN.

[0138] Based on the reception of BlockAck (SSN=1, "100000"), the shared AP 20-1 updates its own reception success / failure information and retransmits data D3 and D5 to the sharing AP 10. The retransmitted data is data with a sequence number SN corresponding to "0" in the received bitmap, and is data that has been accumulated in the transmission buffer. Note that in this example, retransmission is performed only once. Then, based on the fact that the sharing AP 10 has successfully received data D3 and failed to receive data D5, the shared AP 20-1 updates its own reception success / failure information. Thereafter, the shared AP 20-1 checks the reception status after data transmission by transmitting a BlockAck request to the sharing AP 10. In this example, the sharing AP 10 transmits BlockAck (SSN=1, "101000") to the shared AP 20-1 as a response to the BAR. The shared AP 20-1 updates its own reception success / failure information based on the reception of BlockAck (SSN=1, "101000").

[0139] The shared AP 20-2 stores the received data D2, D4, and D6 in the transmission buffer TB, updates its own reception success / failure information, and transmits the data D2, D4, and D6 to the sharing AP 10. Then, the sharing AP 10 updates its own reception success / failure information based on the successful reception of the data D2, D4, and D6. Thereafter, the shared AP 20-2 transmits a BlockAck request to the sharing AP 10, and the sharing AP 10 transmits a BlockAck (SSN=1, "111101") to the shared AP 20-2 as a response to the BAR. Based on the reception of the BlockAck (SSN=1, "111101"), the shared AP 20-2 updates its own reception success / failure information.

[0140] Furthermore, after transmitting data D1 to D6, the non-AP_MLD checks the reception status with a BlockAck request. Specifically, the non-AP_MLD transmits a BlockAck request (SSN=1) to the sharing AP 10. In this example, the sharing AP 10 transmits a BlockAck (SSN=1, "111101") to the non-AP_MLD as a response to the BAR. As a result, the transmission buffer control unit 341 of the non-AP_MLD determines that reception of data with sequence numbers SN#1 to #4 has been confirmed based on the start sequence number SSN=1 and the bitmap, and shifts the Window Start to the next sequence number SN#5 that has been successfully received in succession. In this example, the window size is set to 6 frames, so the sequence number of the Window End is set to SN#10. The transmission buffer control unit 341 then discards the data whose reception has been confirmed from the transmission buffer. The start sequence number SSN of the subsequent BlockAck request is set to the start sequence number SSN=5 of the shifted window.

[0141] Next, based on the transmission window TW (SSN=5, Window Size=6) and the reception success / failure information, non-AP_MLD outputs data D5, D7, and D9 with odd sequence numbers SN#5, #7, and #9 to A-STA1, and outputs data D2, D4, and D6 with even sequence numbers SN#8 and #10 to A-STA2. Then, A-STA1 transmits data D5, D7, and D9 to shared AP 20-1, and A-STA2 transmits data D8 and D10 to shared AP 20-2.

[0142] The shared AP 20-1 stores the received data D5, D7, and D9 in a transmission buffer and updates its own reception success / failure information. At this time, transmission of data that has already been transmitted from the non-AP_MLD to the shared AP 20 may be omitted. Then, the data D5, D7, and D9 are transmitted to the sharing AP 10. The sharing AP 10 then updates its own reception success / failure information based on the fact that it has successfully received data D5 and failed to receive data D7 and D9. Thereafter, the shared AP 20-1 transmits a BlockAck request to the sharing AP 10, and the sharing AP 10 transmits a BlockAck (SSN=1, "111111") to the shared AP 20-1 as a response to the BAR. Based on the reception of BlockAck (SSN=1, "111111"), the shared AP 20-1 updates its own reception success / failure information and retransmits data D7 and D9 to the sharing AP 10. Then, based on the fact that data D7 was successfully received and that data D9 was not successfully received, the sharing AP 10 updates its own reception success / failure information. Thereafter, the shared AP 20-1 transmits a BlockAck request to the sharing AP 10. Then, the sharing AP 10 transmits BlockAck (SSN=1, "1111111") to the shared AP 20-1 as a response to the BAR. Based on the reception of BlockAck (SSN=1, "1111111"), the shared AP 20-1 updates its own reception success / failure information.

[0143] The shared AP 20-2 accumulates the received data D8 and D10 in a transmission buffer and updates its own reception success / failure information. Then, it transmits the data D8 and D10 to the sharing AP 10. Then, the sharing AP 10 updates its own reception success / failure information based on the successful reception of the data D8 and D10. Thereafter, the shared AP 20-2 transmits a BlockAck request to the sharing AP 10, and the sharing AP 10 transmits a BlockAck (SSN=1, "1111111101") to the shared AP 20-1 as a response to the BAR. Based on the reception of the BlockAck (SSN=1, "1111111101"), the shared AP 20-1 updates its own reception success / failure information.

[0144] Furthermore, after transmitting data D5 and D7 to D10, the non-AP_MLD checks the reception status using a BlockAck request. Specifically, the non-AP_MLD transmits a BlockAck request (SSN=5) to the sharing AP 10. Based on receiving the BlockAck request with SSN=5, the sharing AP 10 shifts the start sequence number of the receive window in the reordering buffer unit 144 to SSN=5. The transmission buffer control unit 142 then discards data with an SSN smaller than the updated start sequence number SSN from the reordering buffer unit 144. Furthermore, the sharing AP 10 transmits a BlockAck (SSN=5, "111101") to the non-AP_MLD as a response to the BAR. As a result, the non-AP_MLD transmission buffer control unit 341 determines that it has confirmed receipt of the data with sequence numbers SN#5 to SN#8 based on the start sequence number SSN=5 and the bitmap, and shifts the Window Start to the next sequence number SN#9 that has been successfully received in succession. In this example, the window size is set to 6 frames, so the Window End sequence number is set to SN#14 (not shown). The transmission buffer control unit 341 then discards the data whose reception has been confirmed from the transmission buffer. The start sequence number SSN in subsequent BlockAck requests is set to the start sequence number SSN=9 of the shifted window.

[0145] Next, based on the transmission window TW (SSN=9, Window Size=6) and the reception success / failure information, non-AP_MLD outputs data D9 and D11 with odd sequence numbers SN#9 and #11 to A-STA1, and outputs data D12 with even sequence number SN#12 to A-STA2. Then, A-STA1 transmits data D9 and D11 to shared AP 20-1, and A-STA2 transmits data D12 to shared AP 20-2.

[0146] The shared AP 20-1 stores the received data D9 and D11 in a transmission buffer and updates its own reception success / failure information. Then, it transmits the data D9 and D11 to the sharing AP 10. Then, the sharing AP 10 updates its own reception success / failure information based on the successful reception of the data D9 and D11. Thereafter, the shared AP 20-1 transmits a BlockAck request to the sharing AP 10, and the sharing AP 10 transmits a BlockAck (SSN=5, "1111111") to the shared AP 20-1 as a response to the BAR. Based on the reception of the BlockAck (SSN=5, "1111111"), the shared AP 20-1 shifts the transmission window TW, updates its own reception success / failure information, and discards from the transmission buffer the data up to sequence number SN=5, for which reception has been confirmed.

[0147] The shared AP 20-2 accumulates the received data D12 in a transmission buffer and updates its own reception success / failure information. Then, it transmits the data D12 to the sharing AP 10. Then, the sharing AP 10 updates its own reception success / failure information based on the successful reception of the data D12. Thereafter, the shared AP 20-2 transmits a BlockAck request to the sharing AP 10, and the sharing AP 10 transmits a BlockAck (SSN=5, "11111111") to the shared AP 20-2 as a response to the BAR. Based on the reception of the BlockAck (SSN=5, "11111111"), the shared AP 20-2 shifts the transmission window TW, updates its own reception success / failure information, and discards from the transmission buffer the data up to sequence number SN=5, for which reception has been confirmed.

[0148] After transmitting data D9, D11, and D12, the non-AP_MLD checks the reception status using a BlockAck request. Specifically, the non-AP_MLD transmits a BlockAck request (SSN=9) to the sharing AP 10. Based on receiving the BlockAck request with SSN=9, the sharing AP 10 shifts the start sequence number of the receive window in the reordering buffer unit 144 to SSN=9. The transmission buffer control unit 142 then discards data with an SSN smaller than the updated start sequence number SSN from the reordering buffer unit 144. Furthermore, the sharing AP 10 transmits a BlockAck (SSN=9, "1111") to the non-AP_MLD as a response to the BAR. As a result, the non-AP_MLD transmission buffer control unit 341 determines that reception of data with sequence numbers SN#9 to SN#12 has been confirmed based on the start sequence number SSN=9 and the bitmap, and shifts the Window Start to the next sequence number SN that has been successfully received.The transmission buffer control unit 341 then discards the data whose reception has been confirmed from the transmission buffer.

[0149] After that, when the shared AP 20-1 sends a BlockAck request to the sharing AP 10, the sharing AP 10 sends a BlockAck (SSN=9, "1111") as a response to the BAR to the shared AP 20-1. Based on the reception of the BlockAck (SSN=9, "1111"), the shared AP 20-1 shifts the transmission window TW, updates its own reception success / failure information, and discards data up to sequence number SN=9, for which reception has been confirmed, from the transmission buffer.

[0150] Similarly, the shared AP 20-2 sends a BlockAck request to the sharing AP 10, and the sharing AP 10 sends a BlockAck (SSN=9, "1111") as a response to the BAR to the shared AP 20-2. Based on the reception of the BlockAck (SSN=9, "1111"), the shared AP 20-2 shifts the transmission window TW, updates its own reception success / failure information, and discards data up to sequence number SN=9, for which reception has been confirmed, from the transmission buffer.

[0151] As described above, in the data transfer sequence in the information communication system 1 according to the embodiment, the settings of the transmission window TW in each transmission buffer are synchronized. The above description has been given of an example in which upstream traffic is transferred in a multi-AP connection, i.e., the non-AP_MLD is the transmitting station TX and the sharing AP 10 is the receiving station RX, but this is not limiting. Even in the case in which downstream traffic is transferred in a multi-AP connection, i.e., the non-AP_MLD is the receiving station RX and the sharing AP is the transmitting station TX, the same operation can be performed by interchanging the operation of the sharing AP 10 and the operation of the non-AP_MLD described above.

[0152] <3> Effects of the embodiment Next, effects of the information communication system 1 according to the embodiment will be described.

[0153] In the information communication system 1 according to the embodiment, each shared AP 20 stores the data it transmits in a transmission buffer and manages the reception status of the data. Based on the reception status for all sequence numbers SN (not limited to data transmitted by the shared AP) included in BlockAck from the sharing AP 10 (in the case of upstream traffic) or non-AP_MLD (in the case of downstream traffic), the shared AP 20 updates reception success / failure information and controls the transmission window TW. For sequence numbers SN for which reception has been confirmed in order from the top, the shared AP 20 shifts the transmission window TW, discards the buffered data, and transmits data corresponding to the sequence numbers SN newly added to the transmission window TW.

[0154] In this way, in the information communication system 1 according to the embodiment, the transmission buffer is controlled by observing the reception status of all sequence numbers SN, regardless of the traffic being transmitted / buffered by each device (sharing AP 10, shared AP 20, and terminal device 30). As a result, when a multi-AP connection is adopted, the control of the transmission buffer of the shared AP 20 becomes clear, and the window control of the transmission buffer is synchronized end-to-end / overall system, including each shared AP 20.

[0155] As described above, the information communication system 1 according to the embodiment can provide the shared AP 20, the transmitting station TX, and the receiving station RX that can appropriately control the window of the transmission buffer throughout the information communication system 1 when the multi-AP function is used. Furthermore, the information communication system 1 according to the embodiment can reliably transmit data end-to-end without the risk of malfunction by synchronizing window control. Furthermore, the information communication system 1 according to the embodiment can perform retransmission control at the shared AP 20 level, thereby improving data transmission efficiency.

[0156] <4> Others The conversion process from radio frames to radio signals described in the embodiments includes, for example, convolutional coding, interleaving, subcarrier modulation, inverse fast Fourier transform, OFDM modulation, and frequency conversion. The conversion process from radio signals to radio frames described in the embodiments includes, for example, frequency conversion, OFDM demodulation, fast Fourier transform, subcarrier demodulation, deinterleaving, and Viterbi decoding. In this specification, a BlockAck may be referred to as a receipt confirmation frame. A BlockAck request may be referred to as a receipt confirmation request frame.

[0157] In the embodiments, the CPU 11 of the sharing AP 10, the CPU 21 of the shared AP 20, and the CPU 31 of the terminal device 30 may each be other circuits. For example, the sharing AP 10, the shared AP 20, and the terminal device 30 may each include an MPU (Micro Processing Unit) instead of a CPU. Each of the processes described in the embodiments may be realized by dedicated hardware. The processes of the sharing AP 10, the shared AP 20, and the terminal device 30 may be a mixture of processes executed by software and processes executed by hardware, or may be only one of them. The CPU may be called a "processor." The wireless communication module may be called a "communication circuit."

[0158] In the embodiments, the flowcharts used to explain the operations are merely examples. The order of the operations described in the embodiments may be changed to the extent possible, and other processes may be added. For example, the link setup method and data transfer method described in the embodiments are merely examples. A wireless communication standard other than the IEEE 802.11 standard may be used as the wireless communication standard.

[0159] 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.

[0160] DESCRIPTION OF SYMBOLS 1... Information communication system 10... Sharing access point 20... Shared access point 30... Terminal device 11, 21, 31... CPU 12, 22, 32... ROM 13, 23, 33... RAM 14, 24, 34... Wireless communication module 15... Wired communication module 35... Display 36... Storage 110, 310... LLC processing unit 120, 240, 320... Data processing unit 130, 220, 330... Management unit 131... Multi-AP management information 132, 221, 331... Link management information 140, 230, 340... Frame processing unit 141, 351... MAC frame generation unit 142, 231, 341... Transmission buffer control unit 143, 232, 342... Reception status management unit 144, 233, 343... Sorting buffer unit 150, 210-1, 210-2, 352...Transmitting / receiving unit 222...Beacon generating unit 300...Application executing unit 353...MAC frame processing unit SN...Sequence number SSN...Start sequence number TW...Transmission window TB...Transmission buffer RS...Reception status

Claims

1. An access point in an information communication system comprising a transmitting station, an access point having a first wireless link established with the transmitting station, another access point having a second wireless link established with the transmitting station, and a receiving station having a third wireless link with the access point and a fourth wireless link with the other access point, which allocates traffic between the access point and the other access points and transfers data from the transmitting station to the receiving station, the access point comprising: a reception status management unit configured to update reception success / failure information indicating a reception status of data stored in a transmission buffer based on a start sequence number and a bitmap included in a reception confirmation frame received via the first wireless link or the third wireless link; and a transmission buffer control unit configured to accumulate data received via the first wireless link or the third wireless link in the transmission buffer, determine which data of the data accumulated in the transmission buffer is to be transmitted via the first wireless link or the second wireless link based on a transmission window, and shift the transmission window based on the start sequence number included in the reception confirmation frame.

2. The access point according to claim 1, wherein the transmission buffer control unit is configured to set a sequence number indicating the start of the transmission window to a starting sequence number included in the reception confirmation frame.

3. The access point according to claim 1, wherein the transmission buffer control unit is configured to extract, from among the sequence numbers included in the transmission window, those that have a reception status of not yet received and have data stored in the transmission buffer, and transmit the extracted sequence numbers via the first wireless link or the second wireless link.

4. A transmitting station in an information communication system comprising a transmitting station, an access point with which a first wireless link with the transmitting station is established, another access point with which a second wireless link with the transmitting station is established, and a receiving station with which a third wireless link with the access point and a fourth wireless link with the other access point are established, the transmitting station allocating traffic to the access point and the other access points and transferring data from the transmitting station to the receiving station, the transmitting station comprising: a receiving status management unit configured to update reception success / failure information indicating the reception status of data stored in a transmission buffer based on a start sequence number and a bitmap included in a reception confirmation frame received via the first wireless link or the second wireless link; a transmission buffer control unit configured to accumulate data received from an external source in the transmission buffer, determine which data from the data accumulated in the transmission buffer is to be transmitted via the first wireless link or the second wireless link based on a transmission window, transmit an acknowledgement request frame via the first wireless link or the second wireless link, and shift the transmission window so that a start point is a sequence number next to a last sequence number that has been successfully received in succession from a start sequence number included in an acknowledgement frame corresponding to a response to the acknowledgement request frame.

5. The transmitting station according to claim 4, wherein the transmission buffer control unit extracts data whose reception status is unreceived according to the reception success / failure information from among the sequence numbers included in the transmission window, and transmits the data via the first wireless link or the second wireless link.

6. A receiving station in an information communication system comprising a transmitting station, an access point with which a first wireless link with the transmitting station is established, another access point with which a second wireless link with the transmitting station is established, and a receiving station with which a third wireless link with the access point and a fourth wireless link with the other access point are established, and which transfers data from the transmitting station to the receiving station by allocating traffic between the access point and the other access points, the receiving station comprising: a reordering buffer unit that accumulates data correctly received via the third wireless link or the fourth wireless link and reorders the data according to a sequence number; a receiving status management unit configured to update reception success / failure information indicating a data reception status based on a sequence number included in the data received via the third wireless link or the fourth wireless link, to transmit an acknowledgement frame including a start sequence number and a bitmap based on the reception success / failure information via the third wireless link or the fourth wireless link when an acknowledgement request frame is received, and to set a start point of a receiving window of the reordering buffer unit to the start sequence number of the acknowledgement request frame when the sender of the acknowledgement request frame is the transmitting station; A receiving station comprising:

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