Transmitting station

Abstract

To provide a transmitting station that improves the efficiency of data communication during multi-link.SOLUTION: In an information communication system, a transmitting station includes a first wireless signal processing unit, a second wireless signal processing unit, and a buffer unit. The first wireless signal processing unit transmits a wireless signal using a first channel, and the second wireless signal processing unit transmits a wireless signal using a second channel different from the first channel. The buffer unit stores data transmitted to a receiving station using the first wireless signal processing unit and the second wireless signal processing unit establishes multi-link with the receiving station using the first wireless signal processing unit and the second wireless signal processing unit, and upon receiving predetermined information indicating a sequence number of data that has already been received by the receiving station via the first wireless signal processing unit and the second wireless signal processing unit from the receiving station, discards data that corresponds to the sequence number indicated by the predetermined information, out of the stored data.SELECTED DRAWING: Figure 18

Description

Technical Field

[0001] The embodiment relates to a transmitting station.

Background Art

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

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The problem is to improve the efficiency of data communication during multi-link.

Means for Solving the Problems

[0005] The transmitting station of the embodiment includes a first radio signal processing unit, a second radio signal processing unit, and a buffer unit. The first radio signal processing unit is configured to transmit radio signals using a first channel. The second radio signal processing unit is configured to transmit radio signals using a second channel different from the first channel. The buffer unit stores data transmitted to the receiving station using the first and second radio signal processing units. A multilink is established between the first and second radio signal processing units and the receiving station. When the buffer unit receives predetermined information from the receiving station via the first or second radio signal processing unit indicating the sequence number of data already received by the receiving station, it discards the data stored in the buffer unit that corresponds to the sequence number indicated by the predetermined information. [Effects of the Invention]

[0006] The transmitting station of this embodiment can improve the efficiency of data communication during multilink operation. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a conceptual diagram showing an example of the overall configuration of an information and communication system according to the first embodiment. [Figure 2] Figure 2 is a conceptual diagram showing an example of a frequency band used in wireless communication in an information and communication system according to the first embodiment. [Figure 3] Figure 3 is a table showing an example of the link status of a base station and wireless terminal device in the information communication system according to the first embodiment. [Figure 4] Figure 4 is a block diagram showing an example of the hardware configuration of a base station included in the information and communication system according to the first embodiment. [Figure 5] Figure 5 is a block diagram showing an example of the hardware configuration of a wireless terminal device included in the information and communication system according to the first embodiment. [Figure 6] Figure 6 is a block diagram showing an example of the functional configuration of a base station in the information and communication system according to the first embodiment. [Figure 7] Figure 7 is a block diagram showing an example of the functional configuration of a wireless terminal device included in the information and communication system according to the first embodiment. [Figure 8] Figure 8 is a block diagram showing an example of the functional configuration of a transmitting station in an information and communication system according to the first embodiment. [Figure 9] Figure 9 is a block diagram showing an example of the functional configuration of a receiving station in an information and communication system according to the first embodiment. [Figure 10] Figure 10 is a flowchart showing an example of the MAC layer architecture in an information communication system according to the first embodiment. [Figure 11] Figure 11 is a sequence diagram showing an example of how a transmitting station and a receiving station in an information communication system according to the first embodiment transmit and receive traffic assigned to a single link. [Figure 12] Figure 12 is a conceptual diagram showing an example of the A-MPDU format used in communication between a transmitting station and a receiving station in the information communication system according to the first embodiment. [Figure 13] Figure 13 is a conceptual diagram showing an example of a data frame format used in communication between a transmitting station and a receiving station in the information communication system according to the first embodiment. [Figure 14] Figure 14 is a conceptual diagram showing an example of the format of a BlockAck request frame used in communication between a transmitting station and a receiving station in the information communication system according to the first embodiment. [Figure 15] Figure 15 is a conceptual diagram showing an example of the format of a BlockAck frame used in communication between a transmitting station and a receiving station in the information communication system according to the first embodiment. [Figure 16] Figure 16 is a flowchart showing an example of the delivery confirmation process of a transmitting station in an information communication system according to the first embodiment. [Figure 17] Figure 17 is a conceptual diagram showing a specific example of how a transmitting station updates a transmitted bitmap in an information communication system according to the first embodiment. [Figure 18]FIG. 18 is a sequence diagram showing an example of a method for transmitting and receiving traffic assigned to a plurality of links by a transmitting station and a receiving station in the information communication system according to the first embodiment. [Figure 19] FIG. 19 is a flowchart showing an example of the delivery confirmation process of a transmitting station in the information communication system according to the second embodiment. [Figure 20] FIG. 20 is a conceptual diagram showing a specific example of a method for updating a transmission bitmap by a transmitting station in the information communication system according to the second embodiment. [Figure 21] FIG. 21 is a sequence diagram showing an example of a method for transmitting and receiving traffic assigned to a plurality of links by a transmitting station and a receiving station in the information communication system according to a modification of the second embodiment. BEST MODE FOR CARRYING OUT THE INVENTION

[0008] Hereinafter, an information communication system according to an embodiment will be described with reference to the drawings. Each embodiment illustrates an apparatus and a method for embodying the technical idea of the invention. The drawings are schematic or conceptual. In the following, components having substantially the same function and configuration are denoted by the same reference numerals. The numbers after the letters constituting the reference numerals are referred to by the reference numerals including the same letters, and are used to distinguish elements having the same configuration from each other. Similarly, each of the letters after the numbers constituting the reference numerals and "hyphen + number" is referred to by the reference numerals including the same numbers, and is used to distinguish elements having the same configuration from each other. When there is no need to distinguish elements denoted by reference numerals including the same letters or numbers from each other, these elements are referred to by reference numerals including only the letters or numbers.

[0009] <1> First Embodiment Hereinafter, the information communication system 1 according to the first embodiment will be described.

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

[0011] The base station AP is a wireless LAN access point or a wireless LAN router and is configured to be connectable to the network NW. Also, the base station AP is configured to be wirelessly connectable to one or more wireless terminal devices WTA using one type of band or a plurality of types of bands. Note that the base station AP may be wirelessly connected to a wireless repeater (or, in other words, a wireless range extender, relay station, repeater), or may be wirelessly connected to both the wireless terminal device WTA and the wireless repeater.

[0012] The wireless terminal device WTA is a wireless terminal such as a smartphone or a tablet computer. The wireless terminal device WTA is configured to be wirelessly connectable to the base station AP. Note that the wireless terminal device WTA may be other electronic devices such as a desktop computer or a laptop computer. The wireless terminal device WTA may be used as a wireless repeater. In the first embodiment, the case where one wireless terminal device WTA is wirelessly connected to the base station AP will be described as an example.

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

[0014] Wireless communication between a base station AP and a wireless terminal device WTA conforms to the IEEE 802.11 standard. The IEEE 802.11 standard defines the MAC sublayer of Layer 1 and Layer 2 of the OSI (Open Systems Interconnection) reference model. In the OSI reference model, communication functions are divided into seven layers (Layer 1: Physical Layer, Layer 2: Data Link Layer, Layer 3: Network Layer, Layer 4: Transport Layer, Layer 5: Session Layer, Layer 6: Presentation Layer, Layer 7: Application Layer). The data link layer includes the LLC (Logical Link Control) layer and the MAC (Media Access Control) layer. The LLC layer adds DSAP (Destination Service Access Point) headers, SSAP (Source Service Access Point) headers, etc., to data input from a higher-level application to form an LLC packet. The MAC layer adds a MAC header to the LLC packet to form a MAC frame.

[0015] Furthermore, multilink may be used for the radio connection between the base station AP and the wireless terminal device WTA. Multilink is a radio connection that allows data to be sent and received using multiple links. In a pair of wirelessly connected base station APs and wireless terminal devices WTAs, one operates as a transmitting station and the other as a receiving station. The transmitting station may transmit a radio signal containing data input from a higher-level application using at least one link that constitutes the multilink. The receiving station may receive the radio signal transmitted by the transmitting station and recover the data contained in the radio signal using at least one link that constitutes the multilink. In the following description, the transmitting station is denoted with the code "TX" and the receiving station is denoted with the code "RX".

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

[0017] (An example of link status) Figure 3 is a table showing an example of the link status of a base station AP and a wireless terminal device WTA provided in the information communication system 1 according to the first embodiment. This table is provided, for example, in the link management unit of the base station AP. The base station AP and the wireless terminal device WTA manage the link status using, for example, the table shown in Figure 3. Hereinafter, the table for managing the status of a multilink will be referred to as "link management information". In this embodiment, the case in which a multilink in the state shown in Figure 3 is established will be explained as an example. As shown in Figure 3, the link management information includes, for example, information on STA function, link, frequency band, channel ID, link destination ID, multilink, and TID (Traffic IDentifier).

[0018] An STA function is a radio signal processing unit provided by both the base station AP and the wireless terminal device WTA. Both the base station AP and the wireless terminal device WTA may have multiple STA functions. One STA function is associated with one link (i.e., channel CH). In the first embodiment, both the base station AP and the wireless terminal device WTA have three STA functions (STA1, STA2, and STA3). STA1, STA2, and STA3 of the base station AP are associated with STA1, STA2, and STA3 of the wireless terminal device WTA, respectively.

[0019] Furthermore, in the first embodiment, the STA1 of both the base station AP and the wireless terminal device WTA is associated with channel CH1 in the 6GHz band. The STA2 of both the base station AP and the wireless terminal device WTA is associated with channel CH2 in the 5GHz band. The STA1 and STA2 of both the base station AP and the wireless terminal device WTA are in a linked state, establishing a multilink. On the other hand, the STA3 of both the base station AP and the wireless terminal device WTA is associated with the 2.4GHz band and is in a linked state.

[0020] A TID is an identifier that indicates the type of traffic (data). Each STA function sends and receives traffic corresponding to the TID assigned to it. Examples of traffic types include "VO (Voice)", "VI (Video)", "BE (Best Effort)", and "BK (Background)". In a multilink, one STA function may be assigned to one TID, or multiple STA functions may be assigned to one TID. In this example, TID#1 is assigned to STA1 and STA2 of the base station AP and WTA, respectively. TID#2 is assigned to STA2 of the base station AP and WTA, respectively. TID#3 is assigned to STA3 of the base station AP and WTA, respectively. Each of TID#1 to #3 corresponds to one of VO, VI, BE, or BK.

[0021] Traffic and STA functions are associated when a multilink is established between a base station AP and a wireless terminal device WTA. For example, the association between traffic and STA functions is set so that the amount of traffic (amount of data) is equal among the multiple links that make up the multilink. However, it is not limited to this, and traffic of similar types (priority / non-priority, etc.) may be grouped together on a specific link that makes up the multilink. The frequency band allocated to the transmission and reception of traffic is preferably selected according to the type of traffic and the amount of data. For example, it is conceivable to associate voice (VO), which has a small amount of data, with the 2.4 GHz frequency band, and video (VI), which has a large amount of data, with the 5 GHz frequency band.

[0022] <1-1-2> Hardware Configuration The following describes an example of the hardware configuration for a base station AP and a wireless terminal (WTA).

[0023] (Base station AP hardware configuration) Figure 4 is a block diagram showing an example of the hardware configuration of a base station AP included in the information communication system 1 according to the first embodiment. As shown in Figure 4, the base station AP includes, for example, a CPU (Central Processing Unit) 10, ROM (Read Only Memory) 11, RAM (Random Access Memory) 12, a wireless communication module 13, and a wired communication module 14.

[0024] The CPU 10 is an integrated circuit capable of executing various programs and controls the overall operation of the base station AP. The ROM 11 is a non-volatile semiconductor memory that stores programs and control data for controlling the base station AP. The RAM 12 is, for example, a volatile semiconductor memory and is used as a workspace for the CPU 10. The wireless communication module 13 is a circuit used for transmitting and receiving data via wireless signals and is configured to be connectable to an antenna. The wireless communication module 13 may also include multiple communication modules corresponding to multiple frequency bands. The wired communication module 14 is a circuit used for transmitting and receiving data via wired signals and is configured to be connectable to a network NW. Note that the base station AP may have other hardware configurations. For example, if the base station AP is wirelessly connected to a network NW, the wired communication module 14 may be omitted from the base station AP.

[0025] (Hardware configuration of the wireless terminal device WTA) Figure 5 is a block diagram showing an example of the hardware configuration of a wireless terminal device WTA included in the information communication system 1 according to the first embodiment. As shown in Figure 5, the wireless terminal device WTA includes, for example, a CPU 20, ROM 21, RAM 22, a wireless communication module 23, a display 24, and storage 25.

[0026] The CPU 20 is an integrated circuit capable of executing various programs and controls the overall operation of the wireless terminal device WTA. The ROM 21 is a non-volatile semiconductor memory that stores programs and control data for controlling the wireless terminal device WTA. The RAM 22 is, for example, a volatile semiconductor memory and is used as a workspace for the CPU 20. The wireless communication module 23 is a circuit used for sending and receiving data via wireless signals and is configured to be connectable to an antenna. The wireless communication module 23 may also include, for example, multiple communication modules corresponding to multiple frequency bands. The display 24 displays, for example, a GUI (Graphical User Interface) corresponding to application software. The display 24 may also function as an input interface for the wireless terminal device WTA. The storage 25 is a non-volatile storage device that stores, for example, the system software of the wireless terminal device WTA. The wireless terminal device WTA may have other hardware configurations. For example, if the wireless terminal device WTA is an IoT (Internet of Things) terminal, the display 24 may be omitted from the wireless terminal device WTA.

[0027] <1-1-3> Functional Configuration The following describes an example of the functional configuration of a base station AP and an example of the functional configuration of a wireless terminal device WTA. Subsequently, an example of the functional configuration when the base station AP or wireless terminal device WTA operates as a transmitting station TX and an example of the functional configuration when the base station AP or wireless terminal device WTA operates as a receiving station RX are described.

[0028] (Functional configuration of base station APs) Figure 6 is a block diagram showing an example of the functional configuration of a base station AP provided by the information communication system 1 according to the first embodiment. As shown in Figure 6, the base station AP includes, for example, a data processing unit 30a, a MAC frame processing unit 40a, a management unit 50a, and radio signal processing units 60-1a, 60-2a, and 60-3a. The processing of the data processing unit 30a, MAC frame processing unit 40a, management unit 50a, and radio signal processing units 60-1a, 60-2a, and 60-3a is realized, for example, by a CPU 10 and a wireless communication module 13.

[0029] The data processing unit 30a can perform LLC layer and upper layer processing on the input data. When the base station AP is a transmitting station TX, the data processing unit 30a inputs the data received from the server SV via the network NW to the MAC frame processing unit 40a. When the base station AP is a receiving station RX, the data processing unit 30a transmits the data received from the MAC frame processing unit 40a to the server SV via the network NW.

[0030] The MAC frame processing unit 40a performs a portion of the MAC layer processing on the input data. When the base station AP is a transmitting station TX, the MAC frame processing unit 40a generates a MAC frame from the data input from the data processing unit 30a. When the base station AP is a receiving station RX, the MAC frame processing unit 40a reconstructs data from the MAC frames input from the radio signal processing units 60-1a, 60-2a, and 60-3a, respectively. The MAC frame processing unit 40a can also perform processing based on instructions from the management unit 50a and exchange information with the management unit 50a.

[0031] The management unit 50a manages the link status with the wireless terminal device WTA based on notifications received from the wireless signal processing units 60-1a, 60-2a, and 60-3a via the MAC frame processing unit 40a. The management unit 50a includes link management information 51a, an association processing unit 52a, and an authentication processing unit 53a. The link management information 51a is stored, for example, in RAM 12 and includes information about the wireless terminal device WTA to which the base station AP is wirelessly connected. The association processing unit 52a executes an association protocol when it receives a connection request from the wireless terminal device WTA via any of the wireless signal processing units 60-1a, 60-2a, and 60-3a. The authentication processing unit 53a executes an authentication protocol following the connection request.

[0032] Each of the radio signal processing units 60-1a, 60-2a, and 60-3a transmits and receives data between the base station AP and the wireless terminal device WTA via wireless communication. Specifically, each of the radio signal processing units 60-1a, 60-2a, and 60-3a can perform some MAC layer processing and first layer processing on the input data or radio signal. When the base station AP is the transmitting station TX, each of the radio signal processing units 60-1a, 60-2a, and 60-3a adds a preamble, PHY (physical layer) header, etc., to the data input from the MAC frame processing unit 40a to create a radio frame. Then, each of the radio signal processing units 60-1a, 60-2a, and 60-3a converts the radio frame into a radio signal and distributes the converted radio signal via the base station AP's antenna. When the base station AP is the receiving station RX, each of the radio signal processing units 60-1a, 60-2a, and 60-3a converts the radio signal received via the base station AP's antenna into a radio frame. Then, each of the radio signal processing units 60-1a, 60-2a, and 60-3a inputs the data contained in the radio frame to the MAC frame processing unit 40a. Note that the radio signal processing units 60-1a, 60-2a, and 60-3a may or may not share the base station AP's antenna. In this example, the radio signal processing units 60-1a, 60-2a, and 60-3a handle radio signals in the 6GHz band, 5GHz band, and 2.4GHz band, respectively. In other words, the radio signal processing units 60-1a, 60-2b, and 60-3b correspond to STA1, STA2, and STA3 of the base station AP, respectively.

[0033] In the following, the set of data processing unit 30a, MAC frame processing unit 40a, and management unit 50a provided by the base station AP will be referred to as the "link management unit LM1". The link management unit LM1 can determine the correspondence between traffic and STA functions when establishing a multilink between the base station AP and the wireless terminal device WTA.

[0034] (Functional configuration of the wireless terminal device WTA) Figure 7 is a block diagram showing an example of the functional configuration of a wireless terminal device WTA included in the information communication system 1 according to the first embodiment. As shown in Figure 7, the wireless terminal device WTA includes, for example, a data processing unit 30b, a MAC frame processing unit 40b, a management unit 50b, wireless signal processing units 60-1b, 60-2b, and 60-3b, and an application execution unit 70. The processing of the data processing unit 30b, MAC frame processing unit 40b, management unit 50b, and wireless signal processing units 60-1b, 60-2b, and 60-3b is realized, for example, by a CPU 20 and a wireless communication module 23. The processing of the application execution unit 70 is realized, for example, by a CPU 20.

[0035] The data processing unit 30b can perform LLC layer and upper layer processing on the input data. When the wireless terminal device WTA is a transmitting station TX, the data processing unit 30b inputs the data input from the application execution unit 70 to the MAC frame processing unit 40b. When the wireless terminal device WTA is a receiving station RX, the data processing unit 30b inputs the data input from the MAC frame processing unit 40b to the application execution unit 70.

[0036] The MAC frame processing unit 40b performs a portion of the MAC layer processing on the input data. When the wireless terminal device WTA is a transmitting station TX, the MAC frame processing unit 40b generates a MAC frame from the data input from the data processing unit 30b. When the wireless terminal device WTA is a receiving station RX, the MAC frame processing unit 40b reconstructs data from the MAC frames input from the wireless signal processing units 60-1b, 60-2b, and 60-3b, respectively. The MAC frame processing unit 40b can also perform processing based on instructions from the management unit 50b and exchange information with the management unit 50b.

[0037] The management unit 50b manages the link status with the base station AP based on notifications received from the radio signal processing units 60-1b, 60-2b, and 60-3b via the MAC frame processing unit 40b. The management unit 50b includes link management information 51b, association processing unit 52b, and authentication processing unit 53b. Link management information 51b is stored, for example, in RAM 22 and includes information about the base station AP to which the wireless terminal device WTA is wirelessly connected. The association processing unit 52b executes an association protocol when it receives a connection request from the wireless terminal device WTA via any of the radio signal processing units 60-1b, 60-2b, and 60-3b. The authentication processing unit 53b executes an authentication protocol following the connection request.

[0038] Each of the radio signal processing units 60-1b, 60-2b, and 60-3b transmits and receives data between the base station AP and the radio terminal device WTA via wireless communication. Specifically, each of the radio signal processing units 60-1b, 60-2b, and 60-3b can perform part of the MAC layer processing and the first layer processing on the input data or radio signal. More specifically, when the radio terminal device WTA is the transmitting station TX, each of the radio signal processing units 60-1b, 60-2b, and 60-3b adds a preamble, PHY header, etc., to the data input from the MAC frame processing unit 40b to create a radio frame. Then, each of the radio signal processing units 60-1b, 60-2b, and 60-3b converts the radio frame into a radio signal and distributes the converted radio signal via the antenna of the radio terminal device WTA. When the wireless terminal device WTA is the receiving station RX, each of the wireless signal processing units 60-1b, 60-2b, and 60-3b converts the wireless signal received via the WTA's antenna into a wireless frame. Then, each of the wireless signal processing units 60-1b, 60-2b, and 60-3b inputs the data contained in the wireless frame to the MAC frame processing unit 40b. Note that the wireless signal processing units 60-1b, 60-2b, and 60-3b may or may not share the WTA's antenna. In this example, the wireless signal processing units 60-1b, 60-2b, and 60-3b handle wireless signals in the 6GHz band, 5GHz band, and 2.4GHz band, respectively. In other words, the wireless signal processing units 60-1b, 60-2b, and 60-3b correspond to STA1, STA2, and STA3 of the WTA, respectively.

[0039] The application execution unit 70 executes an application that can utilize the data input from the data processing unit 30b. The application execution unit 70 inputs data to the data processing unit 30b and retrieves data from the data processing unit 30b according to the application's operation. The application execution unit 70 can display application information on the display 24. Furthermore, the application execution unit 70 can execute processing in response to operations via the input interface.

[0040] Hereinafter, the set of data processing unit 30b, MAC frame processing unit 40b, and management unit 50b provided in the wireless terminal device WTA will be referred to as the “link management unit LM2”. The link management unit LM2 can determine the mapping between traffic and STA functions when establishing a multilink between the base station AP and the wireless terminal device WTA. For example, during multilink setup, the link management unit LM2 determines the mapping between traffic and STA functions and requests the base station AP's link management unit LM1 to apply this mapping. When the wireless terminal device WTA receives an acknowledgment of this request from the base station AP, the mapping between traffic and STA functions is finalized.

[0041] (Functional configuration of the transmitting station TX) Figure 8 is a block diagram showing an example of the functional configuration of a transmitting station TX in the information communication system 1 according to the first embodiment. The transmitting station TX is either a base station AP or a wireless terminal device WTA, and Figure 8 shows a more detailed functional configuration of a base station AP or wireless terminal device WTA operating as a transmitting station TX. Note that in Figure 8, the functional configuration other than the data processing unit 30, the MAC frame processing unit 40, and the two STA functions (STA1 and STA2) is omitted from the illustration.

[0042] As shown in Figure 8, the MAC frame processing unit 40 of the transmitting station TX comprises a data categorization unit 411, a first MAC processing unit 412, a transmit buffer control unit 413, and a data distribution unit 414. The STA function of the transmitting station TX comprises a frame generation unit 610, a storage unit 611, a transmit / receive unit 612, and a frame processing unit 613. Specifically, STA1 of the transmitting station TX comprises a frame generation unit 610-1, a storage unit 611-1, a transmit / receive unit 612-1, and a frame processing unit 613-1, while STA2 of the transmitting station TX comprises a frame generation unit 610-2, a storage unit 611-2, a transmit / receive unit 612-2, and a frame processing unit 613-2.

[0043] The data categorization unit 411 classifies the data input from the data processing unit 30 according to the type of traffic. Specifically, the data categorization unit 411 associates each input data with a TID. Then, the data categorization unit 411 inputs the classified data to the first MAC processing unit 412.

[0044] The first MAC processing unit 412 performs some of the MAC layer processing on the data input from the data categorization unit 411. Specifically, the first MAC processing unit 412 performs A-MSDU (Aggregate-MAC Service Data Unit) aggregation, sequence number SN assignment, fragmentation, and A-MPDU (Aggregate-MAC Protocol Data Unit) encryption, as described later. The first MAC processing unit 412 then inputs the data on which some of the MAC layer processing has been performed (for example, encrypted MPDU) to the transmit buffer control unit 413. MPDU corresponds to a unit of data in the MAC layer.

[0045] The transmit buffer control unit 413 stores the data input from the first MAC processing unit 412. The transmit buffer control unit 413 also stores a transmit bitmap (TBM). The transmit bitmap (TBM) indicates the transmission status of the data stored by the transmit buffer control unit 413. The transmit bitmap (TBM) includes the start sequence number (SSN) and bitmap information (BMI), which will be described later. A transmit bitmap (TBM) may be stored for each TID. The transmit buffer control unit 413 then inputs the stored data to the data distribution unit 414.

[0046] The data distribution unit 414 distributes the data input from the transmission buffer control unit 413 to the frame generation unit 610 of the STA function associated with the TID of the data. Specifically, in this embodiment, the data with TID#1 assigned to STA1 and STA2 is input to either the frame generation unit 610-1 of STA1 or the frame generation unit 610-2 of STA2. The data with TID#2 assigned to STA1 is input to the frame generation unit 610-1 of STA1. The data with TID#3 assigned to STA2 is input to the frame generation unit 610-2 of STA2.

[0047] Furthermore, the multiple functional configurations of each STA function operate similarly. Therefore, in the following explanation, we will focus on one STA function (STA1 of the transmitting station TX) to describe the multiple functional configurations of each STA function.

[0048] The frame generation unit 610-1 performs some of the MAC layer processing on the data input from the data distribution unit 414. Specifically, the frame generation unit 610-1 generates wireless frames by adding MAC headers and error detection codes (described later) and performing A-MPDU (Aggregate-MAC Protocol Data Unit) aggregation. The frame generation unit 610-1 then inputs the generated wireless frames (e.g., A-MPDUs) to the storage unit 611-1. The frame generation unit 610-1 can also generate wireless frames (BlockAck request frames) containing BlockAck (Block Acknowledgment) requests input from the link management unit LM and input them to the storage unit 611-1. BlockAck requests are generated, for example, by the transmit buffer control unit 413 of the link management unit LM.

[0049] The storage unit 611-1 temporarily stores the wireless frames input from the frame generation unit 610-1. The wireless frames stored in the storage unit 611-1 are input to the transmitting / receiving unit 612-1. In other words, the storage unit 611-1 stores the data (wireless frames) waiting to be transmitted by the STA function. The storage unit 611-1 then discards the data transmitted by the transmitting / receiving unit 612-1. The storage unit 611-1 may also notify the transmitting buffer control unit 413 of information regarding the data waiting to be transmitted stored in the storage unit 611-1 in response to an inquiry from the transmitting buffer control unit 413. For example, TID information and sequence number SN may be used as information for the stored data.

[0050] The transmitting / receiving unit 612-1 performs physical layer processing on the data (wireless frame) input from the storage unit 611-1. The transmitting / receiving unit 612-1 is equipped with a transmission queue capable of temporarily storing data for each TID, for example, and has a channel access function capable of performing CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance), etc. The transmitting / receiving unit 612-1 then transmits a wireless signal containing the data input from the storage unit 611-1 via the antenna. Furthermore, after transmitting the data stored in the transmission buffer control unit 413 wirelessly, when the transmitting / receiving unit 612-1 receives a wireless signal containing BlockAck transmitted by the receiving station RX via the antenna, it inputs the BlockAck contained in the wireless signal to the frame processing unit 613-1.

[0051] The frame processing unit 613-1 performs a portion of the MAC layer processing on the BlockAck frame input from the transmitting / receiving unit 612-1. The frame processing unit 613-1 then inputs the BlockAck to the transmit buffer control unit 413 in the link management unit LM. The link management unit LM checks whether the data has been received by the receiving station RX based on the start sequence number SSN and bitmap information BMI indicated by the BlockAck input to the transmit buffer control unit 413, and updates the contents of the transmit bitmap TBM. The link management unit LM of the transmitting station TX then deletes the data that has been confirmed to have been received by the receiving station RX from the transmit buffer control unit 413. On the other hand, if there is data that has been confirmed not to have been received by the receiving station RX, the link management unit LM performs a retransmission process for the data that has been confirmed not to have been received by the receiving station RX.

[0052] In CSMA / CA, access parameters are assigned in the order of priority for radio signal transmission, for example, VO, VI, BE, BK. Access parameters include, for example, CWmin, CWmax, AIFS, and TXOPLimit. CWmin and CWmax represent the minimum and maximum values ​​of the Contention Window, which is the transmission waiting time for collision avoidance. AIFS (Arbitration Inter Frame Space) represents a fixed transmission waiting time set for each access category for collision avoidance control with priority control functionality. TXOPLimit represents the upper limit of TXOP (Transmission Opportunity) corresponding to the channel occupancy time. For example, the shorter the CWmin and CWmax, the easier it is to obtain transmission rights in the transmission queue. The priority of the transmission queue increases as the AIFS value decreases. The amount of data transmitted in a single transmission right increases as the TXOPLimit value increases.

[0053] (Functional configuration of the receiving station RX) Figure 9 is a block diagram showing an example of the functional configuration of a receiving station RX in the information communication system 1 according to the first embodiment. The receiving station RX is either a base station AP or a wireless terminal device WTA, and Figure 9 shows a more detailed functional configuration of a base station AP or wireless terminal device WTA operating as a receiving station RX. Note that in Figure 9, the functional configuration other than the data processing unit 30, the MAC frame processing unit 40, and the two STA functions (STA1 and STA2) is omitted from the illustration.

[0054] As shown in Figure 9, each STA function of the receiving station RX comprises a transmitting / receiving unit 620, a frame processing unit 621, a reception success / failure determination unit 622, and a frame generation unit 623. Specifically, STA1 of the receiving station RX comprises a transmitting / receiving unit 620-1, a frame processing unit 621-1, a reception success / failure determination unit 622-1, and a frame generation unit 623-1, while STA2 of the receiving station RX comprises a transmitting / receiving unit 620-2, a frame processing unit 621-2, a reception success / failure determination unit 622-2, and a frame generation unit 623-2. The MAC frame processing unit 40 of the receiving station RX comprises a reception status management unit 421, a second MAC processing unit 422, a reordering buffer unit 423, and a third MAC processing unit 424. Note that the multiple functional configurations of each STA function can operate similarly. Therefore, in the following, the multiple functional configurations of each STA function will be explained focusing on one STA function (STA1 of the receiving station RX).

[0055] The transmitting / receiving unit 620-1 performs physical layer processing on the radio signal received via the antenna. When the transmitting / receiving unit 620-1 receives a radio signal containing data transmitted by the transmitting station TX via the antenna, it inputs the data contained in the radio signal to the frame processing unit 621-1.

[0056] The frame processing unit 621-1 performs a portion of the MAC layer processing on the data input from the transmitting / receiving unit 620-1. Specifically, the frame processing unit 621-1 performs A-MPDU deaggregation, etc., as described later. Then, the frame processing unit 621-1 inputs the data on which it has performed a portion of the MAC layer processing to the reception success / failure determination unit 622-1.

[0057] The reception success / failure determination unit 622-1 performs a portion of the MAC layer processing on the data input from the frame processing unit 621-1. Specifically, the reception success / failure determination unit 622-1 performs error detection, etc. Then, the reception success / failure determination unit 622-1 inputs data indicating whether or not there is an error to the reception status management unit 421. The reception success / failure determination unit 622-1 may discard data in which an error has been detected.

[0058] The reception status management unit 421 inputs the traffic-related data from the reception success / failure determination unit 622-1 to the second MAC processing unit 422. The reception status management unit 421 also stores a reception bitmap RBM indicating the data reception status and updates the reception bitmap RBM based on the data input from the reception success / failure determination unit 622-1. Specifically, the reception status management unit 421 manages the reception status of the data corresponding to each sequence number SN using bits of "0" and "1". For example, when data is input, the reception status management unit 421 updates the corresponding bit in the reception bitmap RBM from "0" to "1". Furthermore, if the data input from the reception success / failure determination unit 622-1 includes a BlockAck request, the reception status management unit 421 generates a BlockAck that includes at least a part of the reception bitmap RBM and inputs the generated BlockAck to the frame generation unit 623-1.

[0059] The frame generation unit 623-1 generates a wireless frame (BlockAck frame) that includes BlockAck, which is input from the reception status management unit 421. The frame generation unit 623-1 then inputs the generated wireless frame to the transmitting / receiving unit 620-1. When the transmitting / receiving unit 620-1 receives the wireless frame, it transmits a wireless signal containing the input wireless frame via the antenna.

[0060] The second MAC processing unit 422 performs a portion of the MAC layer processing on the data input from the reception status management unit 421. Specifically, the second MAC processing unit 422 performs MPDU decoding, etc., as described later. Then, the second MAC processing unit 422 inputs the generated data into the sorting buffer unit 423.

[0061] The sorting buffer unit 423 stores the data (MPDU) input from the second MAC processing unit 422 and performs sorting of the stored data. The data sorting is performed based on the sequence number SN included in the stored data (MPDU). The sorting buffer unit 423 then inputs the sorted data to the third MAC processing unit 424.

[0062] The third MAC processing unit 424 performs some of the MAC layer processing on the data input from the sorting buffer unit 423. Specifically, the third MAC processing unit 424 performs defragmentation and A-MSDU deaggregation, which will be described later. Then, the third MAC processing unit 424 inputs the generated data (MSDU) to the data processing unit 30. As a result, the data contained in the radio signal received by the receiving station RX is input to the higher layer.

[0063] <1-2> Operation The operation of the transmitting station TX and receiving station RX in the information communication system 1 according to the first embodiment will be described below. First, an overview of the MAC layer architecture will be described. Next, an example of a method for transmitting and receiving traffic assigned to one link in a multilink configuration, and an example of a method for transmitting and receiving traffic assigned to multiple links will be described.

[0064] <1-2-1> MAC Layer Architecture Figure 10 is a flowchart showing an example of the MAC layer architecture in the information communication system 1 according to the first embodiment. The left side of Figure 10 shows an example of the MAC layer architecture at the transmitting station TX. The right side of Figure 10 shows an example of the MAC layer architecture at the receiving station RX.

[0065] (Transmitter TX processing) As shown on the left side of Figure 10, once the LLC layer processing of the data to be transmitted is complete, the transmitting station TX sequentially executes steps S10 to S16 in the MAC layer.

[0066] In step S10, the first MAC processing unit 412 of the transmitting station TX performs A-MSDU aggregation. A-MSDU aggregation is the 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 by the LLC layer. The first MAC processing unit 412 can create an A-MSDU using multiple MSDUs if they have the same receiving station address and the same TID.

[0067] In step S11, the first MAC processing unit 412 of the transmitting station TX assigns a sequence number SN to each A-MSDU. The first MAC processing unit 412 may manage the sequence number SN for each TID, or it may manage it collectively for multiple TIDs. The sequence number SN is used to identify the portion of the data that the receiving station RX has successfully received.

[0068] In step S12, the first MAC processing unit 412 of the transmitting station TX performs fragmentation on one A-MSDU. Fragmentation is the process of fragmenting (dividing) the A-MSDU. Each fragmented A-MSDU corresponds to an MPDU.

[0069] In step S13, the first MAC processing unit 412 of the transmitting station TX performs MPDU encryption on each MPDU. MPDU encryption is the process of encrypting the MPDU. The encrypted MPDU is configured to be decryptable between the base station AP and the wireless terminal device WTA whose ownership has been established.

[0070] In step S14, the transmit buffer control unit 413 of the transmitting station TX generates and stores the transmit bitmap TBM.

[0071] In step S15, the STA function of the transmitting station TX adds a MAC header and an error detection code to the encrypted MPDU. The MAC header includes the destination and source MAC addresses, the Ethernet type field, etc. The error detection code is used at the receiving station RX to detect errors in the received data. For example, a CRC (Cyclic Redundancy Check) is used as the error detection code.

[0072] In step S16, the STA function of the transmitting station TX performs A-MPDU aggregation. A-MPDU aggregation is the process of combining multiple MPDUs to generate a single A-MPDU. The generated A-MPDU is then input to the physical layer.

[0073] As described above, in the information communication system 1 according to the first embodiment, the processing in steps S10 to S14 is performed by the link management unit LM of the transmitting station TX, and the processing in steps S15 and S16 is performed by the respective STA functions of the transmitting station TX. The link management unit LM of the transmitting station TX may also construct a data frame by adding a header including the sequence number SN to the MPDU. In other words, the processing in step S15 may be performed by the link management unit LM of the transmitting station TX.

[0074] (Processing of the receiving station RX) As shown on the right side of Figure 10, once the physical layer processing of the received radio signal is complete, the receiving station RX sequentially executes steps S20 to S26 in the MAC layer.

[0075] In step S20, the frame processing unit 621 of the receiving station RX's STA function performs A-MPDU deaggregation. A-MPDU deaggregation is the process of deaggregating (dividing) the A-MPDU input from the physical layer into MPDU units.

[0076] In step S21, the reception success / failure determination unit 622 of the receiving station RX's STA function performs error detection. Error detection is a process that detects errors in the received data using an error detection code (e.g., CRC). Error detection in step S21 is performed for each MPDU.

[0077] In step S22, the link management unit LM of the receiving station RX checks the reception status. Specifically, the reception status management unit 421 of the link management unit LM of the receiving station RX determines whether the data (MPDU) has been received successfully based on the success or failure of error detection. If no error is detected, i.e., if the data has been successfully received, the reception status management unit 421 executes the next process using the data. On the other hand, if an error is detected, the reception status management unit 421 discards the data in which the error was detected. The reception status management unit 421 also stores the received bitmap RBM and updates the received bitmap RBM based on the data reception status. In addition, in response to receiving a BlockAck request, the reception status management unit 421 sends a BlockAck containing at least a portion of the received bitmap RBM to the transmitting station TX using the STA function that received the BlockAck request.

[0078] In step S23, the second MAC processing unit 422 of the link management unit LM of the receiving station RX performs MPDU decryption. MPDU decryption is the process of decrypting the encrypted MPDU. Decryption of the MPDU is successful if it is data communicated between a base station AP and a wireless terminal device WTA whose ownership has been established.

[0079] In step S24, the sorting buffer section 423 of the link management section LM of the receiving station RX performs sorting of the decoded MPDUs. The sorting process sorts the MPDUs that were successfully received in the order of their sequence numbers SN.

[0080] In step S25, the third MAC processing unit 424 of the link management unit LM of the receiving station RX performs defragmentation of the rearranged MPDU. Defragmentation is the process of restoring the A-MSDU by combining multiple MPDUs.

[0081] In step S26, the third MAC processing unit 424 of the link management unit LM of the receiving station RX performs A-MSDU deaggregation. A-MSDU deaggregation is the process of dividing the restored A-MSDU into MSDU units. The divided A-MSDUs are input to the LLC layer.

[0082] As described above, in the information communication system 1 according to the first embodiment, the processes in steps S20 to S21 are performed by the STA functions of the receiving station RX, and the processes in steps S22 to S26 are performed by the link management unit LM of the receiving station RX.

[0083] <1-2-2> How to send and receive traffic assigned to a single link Figure 11 is a sequence diagram showing an example of how the transmitting station TX and receiving station RX in the information communication system 1 according to the first embodiment transmit and receive traffic assigned to a single link. Below, using Figure 11, an overview of the operation in which data D#1 and D#2, which have the same TID, are transmitted from the transmitting station TX to the receiving station RX using a single link (STA1) will be explained.

[0084] When data D#1 and D#2 are input from the upper layer, the link management unit LM of the transmitting station TX starts processing the transmission of data D#1 and D#2.

[0085] First, the link management unit LM of the transmitting station TX inputs data D#1, which assigns SN=1, to STA1 of the transmitting station TX (step S30). Data D#1 is stored in the transmit buffer control unit 413 of the link management unit LM of the transmitting station TX.

[0086] Next, the link management unit LM of the transmitting station TX inputs data D#2, which assigns SN=2, to STA1 of the transmitting station TX (step S31). Data D#2 is stored in the transmit buffer control unit 413 of the link management unit LM of the transmitting station TX.

[0087] Next, STA1 of the transmitting station TX transmits an A-MPDU[D#1, D#2] to STA1 of the receiving station RX, which includes an MPDU containing data D#1 and an MPDU containing data D#2 (step S32).

[0088] In this example, STA1 of the receiving station RX, which received A-MPDU[D#1, D#2], detects an error in the MPDU containing data D#1, but does not detect an error in the MPDU containing data D#2. In this case, STA1 of the receiving station RX inputs data D#2 received from the transmitting station TX to the link management unit LM of the receiving station RX (step S33). Then, the link management unit LM of the receiving station RX updates the received bitmap RBM based on the reception result of A-MPDU[D#1, D#2].

[0089] The link management unit LM of the transmitting station TX generates a BlockAck request (BAR) after the transmission of A-MPDU [D#1, D#2] is complete, for example according to a pre-set schedule, and inputs the generated BlockAck request to STA1 of the transmitting station TX (step S34).

[0090] Then, the transmitting station TX's STA1 sends the BlockAck request [SSN=1] received from the link management unit LM to the receiving station RX's STA1 (step S35). This [SSN=1] indicates the content of the BlockAck request. The start sequence number SSN included in the BlockAck request indicates the start sequence number SSN of the BlockAck requested from the receiving station RX.

[0091] When the receiving station RX's STA1 receives a BlockAck request [SSN=1], it inputs the received BlockAck request to the receiving station RX's link management unit LM (step S36).

[0092] When the receiving station RX's link management unit LM receives a BlockAck request, it generates a BlockAck(BA) that includes the portion of the received bitmap RBM specified by SSN=1 in the BlockAck request, and inputs the generated BlockAck[SSN=1, "01"] to the receiving station RX's STA1 (step S37). This BlockAck contains information indicating the reception result of the A-MPDU[D#1, D#2] by the receiving station RX.

[0093] Then, the receiving station RX's STA1 transmits the BlockAck [SSN=1, "01"] input from the link management unit LM to the transmitting station TX's STA1 (step S38). [SSN=1, "01"] indicates the contents of the received bitmap RBM included in the BlockAck. SSN=1 indicates that the starting sequence number SSN indicated by the BlockAck request is "1". "01" corresponds to the bitmap information BMI included in the received bitmap RBM. The first digit of "01" indicates the reception status of the MPDU corresponding to the starting sequence number SSN. The second digit of "01" indicates the reception status of the MPDU corresponding to the sequence number SN that follows the starting sequence number SSN. For example, in the received bitmap RBM, if the bit corresponding to a certain sequence number SN is "1", it indicates that the data for that sequence number SN has been received by the receiving station RX (i.e., the data has been delivered to the receiving station RX). If the bit corresponding to a sequence number SN is "0", it indicates that the data for that sequence number SN has not been received by the receiving station RX.

[0094] When the transmitting station TX's STA1 receives BlockAck[SSN=1, "01"], it inputs the received bitmap RBM contained in BlockAck to the transmitting station TX's link management unit LM (step S39). The transmitting station TX's link management unit LM refers to the start sequence number SSN and bitmap information BMI contained in the input received bitmap RBM. Then, based on the fact that the numerical value associated with SN=2 in the received bitmap RBM is "1", the transmitting station TX's link management unit LM erases the data D#2 with SN=2 from the transmission buffer control unit 413. On the other hand, based on the fact that the numerical value associated with SN=1 in the received bitmap RBM is "0", the transmitting station TX's link management unit LM performs a retransmission process for data D#1. Specifically, the transmitting station TX's link management unit LM inputs the data D#1 with SN=1 to the transmitting station TX's STA1 (step S40). Then, STA1 of the transmitting station TX transmits an A-MPDU[D#1] containing the MPDU including data D#1 to STA1 of the receiving station RX (step S41).

[0095] In this example, STA1 of the receiving station RX, which received A-MPDU[D#1], does not detect an error in the MPDU containing data D#1. In this case, STA1 of the receiving station RX inputs data D#1 received from the transmitting station TX to the link management unit LM of the receiving station RX (step S42). The link management unit LM of the receiving station RX also updates the received bitmap RBM based on the reception result of A-MPDU[D#1].

[0096] When the transmission of A-MPDU[D#1] is completed, the link management unit LM of the transmitting station TX generates a BlockAck request (BAR) according to a pre-set schedule, for example, and inputs the generated BlockAck request to STA1 of the transmitting station TX (step S43).

[0097] Then, the transmitting station TX's STA1 sends the BlockAck request [SSN=1] received from the link management unit LM to the receiving station RX's STA1 (step S44).

[0098] When the receiving station RX's STA1 receives a BlockAck request [SSN=1], it inputs the received BlockAck request to the receiving station RX's link management unit LM (step S45).

[0099] When the receiving station RX's link management unit LM receives a BlockAck request, it generates a BlockAck(BA) that includes the portion of the received bitmap RBM specified by SSN=1 in the BlockAck request, and inputs the generated BlockAck[SSN=1, "11"] to the receiving station RX's STA1 (step S46). This received bitmap RBM contains information indicating the reception result of A-MPDU[D#1] by the receiving station RX.

[0100] Then, STA1 of the receiving station RX transmits BlockAck [SSN=1, “11”], which was input from the link management unit LM, to STA1 of the transmitting station TX (step S47).

[0101] When the transmitting station TX's STA1 receives BlockAck [SSN=1, "11"], it inputs the received bitmap RBM contained in BlockAck to the transmitting station TX's link management unit LM (step S48).

[0102] The link management unit LM of the transmitting station TX refers to the start sequence number SSN and bitmap information BMI contained in the input received bitmap RBM. Based on the fact that the numerical value associated with SN=1 in the received bitmap RBM is "1", the link management unit LM of the transmitting station TX erases the data D#1 with SN=1 from the transmit buffer control unit 413. Subsequently, the transmitting station TX completes the transmission process of data D#1 and D#2 to the receiving station RX in accordance with the fact that data D#1 and D#2 stored in the transmit buffer control unit 413 have been erased.

[0103] (A-MPDU format) Figure 12 is a conceptual diagram showing an example of the format of an A-MPDU used in communication between a transmitting station TX and a receiving station RX in an information communication system 1 according to the first embodiment. As shown in Figure 12, the fields included in the A-MPDU are, for example, A-MPDU subframe #1, A-MPDU subframe #2, ..., A-MPDU subframe #n (where n is an integer of 3 or more). Each A-MPDU subframe includes multiple fields on which error detection is possible. Specifically, an A-MPDU subframe includes an MPDU delimiter, an MPDU, and padding. The MPDU delimiter includes the MPDU length, CRC, and a delimiter identifier. The MPDU length indicates the length of the MPDU included in the A-MPDU subframe. The CRC within the MPDU is used for error detection of the MPDU delimiter. The delimiter identifier is used for detection of the MPDU delimiter. The MPDU includes, for example, a data frame. Note that the format of the A-MPDU may be other formats.

[0104] (MPDU format) Figure 13 is a conceptual diagram showing an example of the MPDU format used in communication between a transmitting station TX and a receiving station RX in the information communication system 1 according to the first embodiment. As shown in Figure 13, the fields included in the MPDU are, for example, a frame control field, a duration field, an address field, a sequence control field, a QoS (Quality of Service) control field, a frame body field, and an FCS (Frame Check Sequence) field. Some of these fields are included, while others are not, depending on the type of wireless frame.

[0105] The frame control field, duration field, address field, sequence control field, and QoS control field correspond to the MPDU header (MAC header). The frame body field is, for example, the field where data is stored. The FCS field stores an error detection code for the pair of MAC header and frame body field and is used to determine whether or not there are errors in the data frame.

[0106] The frame control field stores various control information. For example, the frame control field includes a type value, a subtype value, a To DS (To Distribution System) value, and a From DS (From Distribution System) value. The type value indicates the frame type of the wireless frame. For example, a Type value of "00" indicates that the wireless frame is a management frame. A Type value of "01" indicates that the wireless frame is a control frame. A Type value of "10" indicates that the wireless frame is a data frame. The content of the wireless frame changes depending on the combination of the type value and subtype value. For example, "00 / 1000 (Type value / Subtype value)" indicates that the wireless frame is a beacon signal. The meaning of the To DS value and From DS value differs depending on their combination. For example, "00 (To DS / From DS)" indicates that the data is between terminals within the same IBSS (Independent Basic Service Set). "10 (To DS / From DS)" indicates that the data frame is directed from an external source to the DS (Distribution System). “01 (To DS / From DS)” indicates that the data frame is heading outside of the DS. “11 (To DS / From DS)” is used when configuring a mesh network.

[0107] The duration field indicates the planned duration of use of the wireless link. The address field indicates the BSSID, source address, destination address, sender terminal address, receiver terminal address, etc. The sequence control field may include the sequence number SN of the data frame, the fragment number for fragments, etc. The QoS control field includes, for example, TID information. TID information may be inserted at other locations within the wireless frame. The frame body field contains information depending on the type of frame. For example, if the wireless frame is a data frame, the frame body field stores multiple A-MSDU subframes #1 to #m (where m is an integer of 2 or greater). Each A-MSDU subframe stores the A-MSDU subframe header, MSDU, and padding. The MSDU stores the data communicated between the wireless terminal device (WTA) and the base station (AP).

[0108] (BlockAck request format) Figure 14 is a conceptual diagram showing an example of the format of a BlockAck request frame used in communication between a transmitting station TX and a receiving station RX in the information communication system 1 according to the first embodiment. As shown in Figure 14, the fields included in the BlockAck request frame are a frame control field, a duration field, an address field, a BAR (BlockAck request) control field, a BAR information field, and an FCS field. The configuration of the frame control field, duration field, address field, and FCS field is the same as that of a data frame. The BAR control field indicates information regarding the control of the BlockAck request. The BAR information field indicates, for example, the lowest number among the sequence numbers SN of the MAC frame to which BlockAck is requested. Note that the format of the BlockAck request frame may be other formats.

[0109] (BlockAck format) Figure 15 is a conceptual diagram showing an example of the format of a BlockAck frame used in communication between a transmitting station TX and a receiving station RX in the information communication system 1 according to the first embodiment. As shown in Figure 15, the fields included in the BlockAck frame are a frame control field, a duration field, an address field, a BA (BlockAck) control field, a BA information field, and an FCS field. The configuration of the frame control field, duration field, address field, and FCS field is the same as that of a data frame. The BA control field indicates the type of BlockAck. The BA information field includes a received bitmap RBM. The received bitmap RBM includes a start sequence number SSN and bitmap information BMI. Note that the format of the BlockAck frame may be other formats.

[0110] <1-2-3> How to send and receive traffic assigned to multiple links In the information communication system 1 according to the first embodiment, when a transmitting station TX with a multilink established transmits traffic assigned to multiple links to a receiving station RX, the link management unit LM confirms the data delivery status by sending a BlockAck request via one of the links. The link management unit LM may periodically send BlockAck requests using each link, or it may do so after receiving notification that data has been transmitted from each link. The link management unit LM of the transmitting station TX then confirms whether the data delivery was successful based on the received bitmap RBM in the BlockAck received from the receiving station RX, and performs retransmission processing as appropriate. The following mainly describes the differences between the method of transmitting and receiving traffic assigned to multiple links and the method of transmitting and receiving traffic assigned to a single link.

[0111] (Transmitter TX processing) Figure 16 is a flowchart showing an example of the delivery confirmation process of the transmitting station TX in the information communication system 1 according to the first embodiment. The delivery confirmation process shown in Figure 16 is started when the transmitting station TX receives a BlockAck from the receiving station RX.

[0112] First, the transmit buffer control unit 413 of the transmitting station TX acquires the received bitmap RBM contained in the BlockAck received from the receiving station RX (step S50). Note that the STA function that receives the BlockAck may be any of the multiple STA functions that have established a multilink.

[0113] Then, the transmit buffer control unit 413 updates the transmit bitmap TBM based on the acquired receive bitmap RBM (step S51). The transmit buffer control unit 413 then discards the MPDU corresponding to the sequence number SN that was successfully delivered.

[0114] Next, the transmit buffer control unit 413 checks the data delivery status by referring to the transmit bitmap TBM stored in the transmit buffer control unit 413 (step S52).

[0115] Then, the transmit buffer control unit 413 checks whether or not a sequence number SN that has not been received by the receiving station RX has been detected by the processing in step S52 (step S53).

[0116] If a sequence number SN that has not been received by the receiving station RX is detected (step S53, YES), the transmit buffer control unit 413 and the data distribution unit 414 cause the STA function that received the BlockAck to retransmit the MPDU corresponding to the sequence number SN that has not been received by the receiving station RX (step S54). The transmit buffer control unit 413 and the data distribution unit 414 may transmit the data subject to retransmission using the same STA function as when the delivery failed, or they may transmit it using a different STA function than when the delivery failed. In other words, the link management unit LM of the transmitting station TX may use the link that was used when the delivery failed to retransmit the data, or it may use a different link than when the delivery failed.

[0117] If no sequence number SN that has not been received by the receiving station RX is detected (step S53, NO), the transmission buffer control unit 413 terminates the delivery confirmation process.

[0118] Figure 17 is a conceptual diagram showing a specific example of a method for confirming the delivery status by the transmitting station TX in the information communication system 1 according to the first embodiment. Below, a specific example of a method for confirming the delivery status using the STA function of the transmitting station TX will be described with reference to Figures 10, 16, and 17 as appropriate.

[0119] In this example, the transmit buffer control unit 413 of the transmitting station TX stores a transmit bitmap TBM containing the start sequence number SSN=1 and bitmap information BMI=“11111111” (step S14). In this example, if the bit corresponding to a sequence number SN in the transmit bitmap TBM is “1”, it indicates that the data for that sequence number SN has been output from the transmit buffer control unit 413 for transmission, but it has not been confirmed that it has been received by the receiving station TX. If the bit corresponding to a sequence number SN in the transmit bitmap TBM is “0”, it indicates that the data for that sequence number SN has been received by the receiving station RX (i.e., the data has been delivered to the receiving station RX).

[0120] The transmit buffer control unit 413 receives a BlockAck containing the received bitmap RBM [SSN=1, BMI=“10001000”] via, for example, STA1 of the transmit station TX, after the A-MPDU associated with the transmit bitmap TBM has been transmitted to the receive station RX by one of the STAs of the transmit station TX (step S50).

[0121] Then, the transmit buffer control unit 413 updates the transmit bitmap TBM based on the received bitmap RBM [SSN=1, BMI=“10001000”] (step S51). In this example, since the bits associated with SN=1 and the bits associated with SN=5 are both “1” in the received bitmap RBM, the transmit buffer control unit 413 detects that the delivery of the data for SN=1 and the data for SN=5 has been successful, and updates the bits that have been successfully delivered to “0” in the transmit bitmap TBM.

[0122] The transmit buffer control unit then detects that the data for SN=2-4 and SN=7-8 in the transmit bitmap TBM has not been received by the receiving station RX, meaning that the data for these sequence numbers SN are to be retransmitted, based on the fact that each of the multiple bits associated with SN=2, SN=3, SN=4, SN=6, SN=7, and SN=8 in the transmit bitmap TBM is "1" (step S53).

[0123] As described above, the link management unit LM of the transmitting station TX updates the transmission bitmap TBM based on the received bitmap RBM included in the received BlockAck. The link management unit LM of the transmitting station TX then performs the retransmission process for sequence number SN data that has not been delivered in the transmission bitmap TBM. Note that the numbers of each bit in the transmission bitmap TBM may be other numbers as long as it is possible to distinguish whether or not they are to be transmitted.

[0124] (Specific example of sending and receiving traffic assigned to multiple links) Figure 18 is a sequence diagram showing an example of a communication method using multiple links between the transmitting station TX and the receiving station RX in the information communication system 1 according to the first embodiment. Below, an overview of the operation in which data D#1, D#2, D#3, and D#4, which have the same TID, are transmitted from the transmitting station TX to the receiving station RX using multiple links (STA1 and STA2) will be explained using Figure 18.

[0125] When data D#1, D#2, D#3, and D#4 are input from the upper layer, the link management unit LM of the transmitting station TX starts processing the transmission of data D#1, D#2, D#3, and D#4.

[0126] First, the link management unit LM of the transmitting station TX stores data D#1, D#2, D#3, and D#4 in the transmit buffer control unit 413. In this example, sequence numbers SN=1 to 4 are assigned to data D#1 to D#4 respectively, and the transmit bitmap TBM stores the starting sequence number SSN=1.

[0127] Next, the link management unit LM of the transmitting station TX inputs data D#1 to STA1 of the transmitting station TX (step S60).

[0128] Next, the link management unit LM of the transmitting station TX inputs data D#2 to STA2 of the transmitting station TX (step S61).

[0129] Next, the link management unit LM of the transmitting station TX inputs data D#3 to STA1 of the transmitting station TX (step S62).

[0130] Next, the link management unit LM of the transmitting station TX inputs data D#4 to STA2 of the transmitting station TX (step S63).

[0131] In this example, data is input to both STA1 and STA2 of the transmitting station TX. The data transmission sequences by STA1 of both the transmitting station TX and the receiving station RX, and the data transmission sequences by STA2 of both the transmitting station TX and the receiving station RX, can be executed in parallel. To simplify the explanation, we will first describe the A-MPDU transmission sequence by STA1 of the transmitting station TX.

[0132] The transmitting station TX's STA1 transmits an A-MPDU[D#1, D#3] to the receiving station RX's STA1, which includes an MPDU containing data D#1 and an MPDU containing data D#3 (step S64).

[0133] In this example, STA1 of the receiving station RX, which received A-MPDU[D#1, D#3], detects an error in the MPDU containing data D#1, but does not detect an error in the MPDU containing data D#3. In this case, STA1 of the receiving station RX inputs data D#3 received from the transmitting station TX to the link management unit LM of the receiving station RX (step S65). Then, the link management unit LM of the receiving station RX updates the received bitmap RBM based on this reception result and stores data D#3 in the sorting buffer unit 423.

[0134] The link management unit LM of the transmitting station TX generates a BlockAck request (BAR) after the transmission of A-MPDU[D#1, D#3] is completed, for example according to a pre-set schedule, and inputs the generated BlockAck request to STA1 of the transmitting station TX (step S66).

[0135] Then, the transmitting station TX's STA1 sends the BlockAck request [SSN=1] input from the link management unit LM to the receiving station RX's STA1 (step S67). This [SSN=1] indicates a request to the receiving station RX to confirm the delivery status of data from sequence number SN=1 onwards.

[0136] When the receiving station RX's STA1 receives a BlockAck request [SSN=1], it inputs the received BlockAck request to the receiving station RX's link management unit LM (step S68).

[0137] When the link management unit LM of the receiving station RX receives a BlockAck request, it generates a BlockAck(BA) that includes the portion of the received bitmap RBM specified by the BlockAck request, and inputs the generated BlockAck[SSN=1, “0010”] to the STA1 of the receiving station RX (step S69).

[0138] Then, STA1 of the receiving station RX transmits BlockAck[SSN=1, “0010”], which was input from the link management unit LM, to STA1 of the transmitting station TX (step S70). [SSN=1, “0010”] indicates that the receiving station RX has successfully received data D#3 with SN=3.

[0139] The STA1 of the transmitting station TX inputs the received bitmap RBM [SSN=1, "0010"] contained in the received BlockAck to the link management unit LM of the transmitting station TX (step S71).

[0140] The link management unit of the transmitting station TX detects, based on the received bitmap RBM [SSN=1, "0010"] received via the STA1 of the transmitting station TX, that data D#3 (SN=3) has been received by the receiving station RX, and that data D#1 (SN=1), data D#2 (SN=2), and data D#4 (SN=4) have not been received by the receiving station RX, and updates the transmitted bitmap TBM. The link management unit LM of the transmitting station TX then deletes data D#3 (SN=3) that was received by the receiving station RX from the transmit buffer control unit 413. The link management unit LM of the transmitting station TX also causes the STA1 of the transmitting station TX to perform retransmission processing for data D#1, D#2, and D#4 that were not received by the receiving station RX.

[0141] Specifically, the link management unit LM of the transmitting station TX inputs data D#1 to STA1 of the transmitting station TX (step S72).

[0142] Next, the link management unit LM of the transmitting station TX inputs data D#2 to STA1 of the transmitting station TX (step S73).

[0143] Next, the link management unit LM of the transmitting station TX inputs data D#4 to STA1 of the transmitting station TX (step S74). The retransmission process for data D#1, D#2, and D#4 will be described later.

[0144] Next, we will explain the transmission sequence of A-MPDU by the transmitting station TX using STA2.

[0145] The transmitting station TX's STA2 transmits an A-MPDU[D#2, D#4] to the receiving station RX's STA2, which includes an MPDU containing data D#2 and an MPDU containing data D#4 (step S75).

[0146] In this example, the STA2 of the receiving station RX, which received A-MPDU[D#2, D#4], does not detect any errors in either MPDU data D#2 or D#4. In this case, the STA2 of the receiving station RX inputs the data D#2 received from the transmitting station TX to the link management unit LM of the receiving station RX (step S76). The link management unit LM of the receiving station RX then updates the received bitmap RBM based on this reception result and stores the data D#2 in the sorting buffer unit 423.

[0147] Next, STA2 of the receiving station RX inputs the data D#4 received from the transmitting station TX to the link management unit LM of the receiving station RX (step S77). Then, the link management unit LM of the receiving station RX updates the received bitmap RBM based on this reception result and stores the data D#4 in the sorting buffer unit 423.

[0148] The link management unit LM of the transmitting station TX generates a BlockAck request (BAR) after the transmission of A-MPDU [D#2, D#4] is complete, for example according to a pre-set schedule, and inputs the generated BlockAck request to STA2 of the transmitting station TX (step S78).

[0149] Then, STA2 of the transmitting station TX sends the BlockAck request [SSN=1] input from the link management unit LM to STA1 of the receiving station RX (step S79).

[0150] When the receiving station RX's STA2 receives a BlockAck request [SSN=1], it inputs the received BlockAck request to the receiving station RX's link management unit LM (step S80).

[0151] When the link management unit LM of the receiving station RX receives a BlockAck request, it generates a BlockAck(BA) that includes the portion of the received bitmap RBM specified by the BlockAck request, and inputs the generated BlockAck[SSN=1, “0111”] to the STA2 of the receiving station RX (step S81).

[0152] Then, the receiving station RX's STA2 transmits the BlockAck [SSN=1, “0111”] input from the link management unit LM to the transmitting station TX's STA2 (step S82). [SSN=1, “0111”] indicates that the receiving station RX has successfully received data D#2 to 4 with SN=2 to 4.

[0153] The STA2 of the transmitting station TX inputs the received bitmap RBM [SSN=1, “0111”] contained in the received BlockAck to the link management unit LM of the transmitting station TX (step S83).

[0154] The link management unit LM of the transmitting station TX detects, based on the received bitmap RBM [SSN=1, "0111"] received via the transmitting station TX's STA2, that data D#2~4 with SN=2~4 has been received by the receiving station RX, and that data D#1 with SN=1 has not been received by the receiving station RX, and updates the transmitted bitmap TBM. Then, the link management unit LM of the transmitting station TX instructs the transmitting station TX's STA2 to retransmit data D#1. In this example, a detailed explanation of the retransmission process of data D#1 by the transmitting station TX's STA2 is omitted.

[0155] Here, we will explain the retransmission process of data D#1 by STA1 of the transmitting station TX.

[0156] The transmitting station TX's STA1 transmits an A-MPDU [D#1, D#2, D#4] to the receiving station RX's STA1, which includes an MPDU containing data D#1, an MPDU containing data D#2, and an MPDU containing data D#4 (step S84).

[0157] In this example, STA1 of the receiving station RX, which received A-MPDU[D#1], does not detect any errors in the multiple MPDUs, each containing data D#1 to D#3. In this case, STA1 of the receiving station RX inputs data D#1 received from the transmitting station TX to the link management unit LM of the receiving station RX (step S85). The link management unit LM of the receiving station RX then updates the received bitmap RBM based on this reception result and stores data D#1 in the sorting buffer unit 423.

[0158] Next, STA1 of the receiving station RX inputs the data D#2 received from the transmitting station TX to the link management unit LM of the receiving station RX (step S86). Then, since the link management unit LM of the receiving station RX already has data D#2 stored in the sorting buffer unit 423, it discards the duplicate data D#2.

[0159] Next, STA1 of the receiving station RX inputs the data D#4 received from the transmitting station TX to the link management unit LM of the receiving station RX (step S87). Then, since the link management unit LM of the receiving station RX already has data D#4 stored in the sorting buffer unit 423, it discards the duplicate data D#4.

[0160] The link management unit LM of the transmitting station TX generates a BlockAck request (BAR) after the transmission of A-MPDU [D#1, D#2, D#4] is completed, for example according to a pre-set schedule, and inputs the generated BlockAck request to STA1 of the transmitting station TX (step S88).

[0161] Then, the transmitting station TX's STA1 sends the BlockAck request [SSN=1] received from the link management unit LM to the receiving station RX's STA1 (step S89).

[0162] When the receiving station RX's STA1 receives a BlockAck request [SSN=1], it inputs the received BlockAck request to the receiving station RX's link management unit LM (step S90).

[0163] When the link management unit LM of the receiving station RX receives a BlockAck request, it generates a BlockAck(BA) that includes the portion of the received bitmap RBM specified by the BlockAck request, and inputs the generated BlockAck[SSN=1, “1111”] to the STA1 of the receiving station RX (step S91).

[0164] Then, STA1 of the receiving station RX transmits the BlockAck input from the link management unit LM, [SSN=1, “1111”], to STA1 of the transmitting station TX (step S92). [SSN=1, “1111”] indicates that data D#1 to D#4 of SN=1 to D#4 have been successfully received.

[0165] The transmitting station TX's STA1 inputs the received bitmap RBM [SSN=1, “1111”] contained in the received BlockAck to the transmitting station TX's link management unit LM (step S93).

[0166] The link management unit of the transmitting station TX detects that data D#1 to D#4 (SN=1 to D#4) has been received by the receiving station RX based on the received bitmap RBM [SSN=1, "1111"] received via the STA1 of the transmitting station TX, and updates the transmitted bitmap TBM. Then, the link management unit LM of the transmitting station TX erases data D#1 (SN=1) received by the receiving station RX from the transmit buffer control unit 413. Subsequently, the transmitting station TX completes the transmission process of data D#1 to D#4 to the receiving station RX in accordance with the fact that data D#1, D#2, D#3, and D#4 stored in the transmit buffer control unit 413 have been erased.

[0167] <1-3> Effects of the First Embodiment The information communication system 1 according to the first embodiment described above can improve the efficiency of data communication during multilink operation. The effects of the information communication system 1 according to the first embodiment will be described in detail below.

[0168] Each base station AP (Access Point) and wireless terminal (WTA) using a wireless LAN may have multiple STA (Signal Terminal) functions that can utilize different frequency bands, such as 2.4GHz, 5GHz, and 6GHz. In this case, a wireless connection is established between the base station AP and the WTA using, for example, one of the multiple STA functions, and data is transmitted and received. Furthermore, the base station AP and the WTA can establish a multilink using multiple STA functions. Data communication using a multilink can utilize multiple frequency bands, enabling efficient communication and improving communication speed.

[0169] One possible method of operating a multilink is for the transmitting station (TX) to assign the transmission of data with the same TID to multiple STA functions (links). However, in such cases, the sequence number SN of the transmitted data may be discontinuous across each of the links. When the sequence number SN is discontinuous, each STA function of the transmitting station (TX) becomes unable to determine whether unreceived data is due to a reception failure or data that was not transmitted (i.e., data with a missing sequence number SN) when managing the data reception status.

[0170] Therefore, in the information communication system 1 according to the first embodiment, the link management unit LM of the transmitting station TX and the link management unit LM of the receiving station RX ensure consistency in the reception status of the transmitted data. Specifically, the link management unit LM of the transmitting station TX stores a transmission bitmap TBM indicating the sequence number SN of the data to be transmitted, and the link management unit LM of the receiving station RX stores a reception bitmap RBM indicating the sequence number SN of the received data.

[0171] The link management unit (LM) of the receiving station RX updates the received bitmap (RBM) according to the data reception status. The link management unit (LM) of the transmitting station (TX) sends BlockAck requests to the link management unit (LM) of the receiving station RX as needed. When the link management unit (LM) of the transmitting station (TX) receives a BlockAck from the receiving station RX, it updates the transmitted bitmap (TBM) and confirms the data delivered to the receiving station RX.

[0172] As a result, in the information communication system 1 according to the first embodiment, even when data is distributed to multiple links during multilink operation, the reception status is consistent between the transmitting station TX and the receiving station RX, enabling the transmission of data using multiple links. Consequently, the information communication system 1 according to the first embodiment can improve the efficiency of data communication during multilink operation. Furthermore, since the information communication system 1 according to the first embodiment can perform retransmission processing of data that has not been received by the receiving station RX using BlockAck, the reliability of data communication during multilink operation can be improved.

[0173] <2> Second Embodiment The hardware and functional configuration of the information communication system 1 according to the second embodiment is the same as that of the first embodiment. Before executing the retransmission process, the information communication system 1 according to the second embodiment checks the data transmission status by each STA function. The differences between the information communication system 1 according to the second embodiment and the first embodiment are described below.

[0174] <2-1> How to send and receive traffic assigned to multiple links (Transmitter TX processing) Figure 19 is a flowchart showing an example of the delivery confirmation process of the transmitting station TX in the information communication system 1 according to the second embodiment. The delivery confirmation process shown in Figure 19 is started when the transmitting station TX receives a BlockAck from the receiving station RX.

[0175] First, the transmitting station TX acquires the received bitmap RBM, similar to the first embodiment (step S50).

[0176] Then, the link management unit LM of the transmitting station TX updates the transmitted bitmap TBM based on the acquired received bitmap RBM, as in the first embodiment (step S51). In addition, the transmit buffer control unit 413 discards the MPDU corresponding to the sequence number SN that was successfully delivered.

[0177] Next, the link management unit LM of the transmitting station TX checks the sequence number SN of any untransmitted data in each STA function (step S100). Specifically, the transmit buffer control unit 413 queries the storage unit 611 of each STA function that has established a multilink to check whether there is any untransmitted data in each STA function. Also, if there is untransmitted data, the transmit buffer control unit 413 checks the sequence number SN of the untransmitted data.

[0178] Next, the link management unit LM of the transmitting station TX checks the data delivery status by excluding the sequence number SN of the untransmitted data confirmed by the processing in step S101 and referring to the transmission bitmap TBM stored in the transmission buffer control unit 413 (step S101).

[0179] Then, the transmit buffer control unit 413 checks whether or not a sequence number SN that has not been received by the receiving station RX has been detected by the processing in step S101 (step S102).

[0180] If a sequence number SN that has not been received by the receiving station RX is detected (step S102, YES), the transmit buffer control unit 413 and the data distribution unit 414 cause the STA function that received the BlockAck to retransmit the MPDU corresponding to the sequence number SN that has not been received by the receiving station RX (step S54). The transmit buffer control unit 413 and the data distribution unit 414 may transmit the data subject to retransmission using the same STA function as in the case of a delivery failure, or they may transmit it using a different STA function than in the case of a delivery failure.

[0181] If no sequence number SN that has not been received by the receiving station RX is detected (step S102, NO), the transmission buffer control unit 413 terminates the delivery confirmation process.

[0182] Furthermore, it is preferable that the STA functions subject to verification of data delivery status include all STA functions among the multiple STA functions constituting the multilink, except for the STA function used to receive BlockAck. The STA function used to receive BlockAck may or may not have its data delivery status verified. This is because an STA function that has sent a BlockAck request and received BlockAck is highly likely to have sent data awaiting transmission stored in the storage unit 611 before sending the BlockAck request.

[0183] Figure 20 is a conceptual diagram showing a specific example of a method for confirming the delivery status by the transmitting station TX in the information communication system 1 according to the first embodiment. Below, a specific example of a method for confirming the delivery status using the STA function of the transmitting station TX will be described with reference to Figures 10, 19, and 20 as appropriate.

[0184] In this example, the transmit buffer control unit 413 of the transmitting station TX stores a transmit bitmap TBM containing the start sequence number SSN=1 and bitmap information BMI=“11111111” (step S14). After the A-MPDU associated with the transmit bitmap TBM is transmitted to the receiving station RX by one of the STAs of the transmitting station TX, the transmit buffer control unit 413 receives a BlockAck containing the received bitmap RBM [SSN=1, BMI=“10001000”], for example via STA1 of the transmitting station TX (step S50).

[0185] Then, the transmit buffer control unit 413 updates the transmit bitmap TBM based on the received bitmap RBM [SSN=1, BMI=“10001000”] (step S51). In this example, since the bits associated with SN=1 and the bits associated with SN=5 are both “1” in the received bitmap RBM, the transmit buffer control unit 413 detects that the delivery of the data for SN=1 and the data for SN=5 has been successful, and updates the bits in the transmit bitmap TBM that indicate successful delivery to “0”.

[0186] Then, the transmission buffer control unit 413 queries STA2 to confirm that the data with SN=2, 4, 6, and 8 are stored in the storage unit 611-2 as untransmitted data (step S100).

[0187] Then, the transmit buffer control unit 413 refers to the transmit bitmap TBM, excluding SN=2, 4, 6, and 8 (step S101), and since each of the multiple bits associated with SN=3 and SN=7 respectively is "1", it detects that the data for SN=3 and SN=7 has not been received by the receiving station RX, that is, the data for these sequence numbers SN are to be retransmitted (step S102).

[0188] As described above, the link management unit LM of the transmitting station TX updates the transmission bitmap TBM based on the received bitmap RBM included in the received BlockAck. The link management unit LM of the transmitting station TX then removes untransmitted data using each STA function and performs retransmission processing for sequence number SN data that has not been delivered in the transmission bitmap TBM. Note that the numbers of each bit in the transmission bitmap TBM may be other numbers as long as it is possible to distinguish whether or not they are to be transmitted.

[0189] (Specific example of sending and receiving traffic assigned to multiple links) Figure 21 is a sequence diagram showing an example of a communication method using multiple links by a transmitting station TX and a receiving station RX in the information communication system 1 according to the second embodiment. Below, using Figure 21, an overview of the operation in which data D#1, D#2, D#3, and D#4, which have the same TID, are transmitted from the transmitting station TX to the receiving station RX using multiple links (STA1 and STA2) will be explained. Note that the processing of steps S60 to S71 shown in Figure 21 is the same as the processing of steps S60 to S71 shown in Figure 18. The processing of steps S75 to S83 shown in Figure 21 is the same as the processing of steps S75 to S83 shown in Figure 18. Briefly, in this example, as in the first embodiment, STA1 of the transmitting station TX transmits data D#1 and D#3 to the receiving station RX, and the receiving station RX successfully receives data D#3. STA2 of the transmitting station TX transmits data D#2 and D#4 to the receiving station RX, and the receiving station RX successfully receives data D#2 and D#4.

[0190] In the second embodiment, when the link management unit LM of the transmitting station TX receives BlockAck (received bitmap RBM) via STA1 of the transmitting station TX through the processing in steps S66 to S71, it updates the transmitted bitmap TBM and then queries STA2 of the transmitting station TX for the presence of untransmitted data (step S110). That is, in this example, the trigger for querying STA2 of the transmitting station TX for the presence of untransmitted data is that STA1 of the transmitting station TX receives BlockAck. Note that the processing in step S110 is not necessarily initiated by a specific STA function such as STA1 of the transmitting station TX, but is initiated based on the fact that any STA function of the transmitting station TX first received the received bitmap RBM. In this example, it is assumed that at the time of the query by the link management unit LM of the transmitting station TX to STA2, STA2 of the transmitting station TX has not yet transmitted data D#2 and D#4 to the receiving station RX.

[0191] In response to an inquiry from the link management unit LM, the transmitting station TX's STA1 inputs information about untransmitted data stored in the storage unit 611-2 (inquiry result) to the transmitting station TX's link management unit LM (step S111).

[0192] As a result, the link management unit (LM) of the transmitting station (TX) recognizes, based on the query results, that data D#2 and D#4 have not yet been transmitted by STA2. The link management unit (LM) of the transmitting station (TX) also refers to the transmit bitmap (TBM), excluding data D#2 and D#4, and recognizes that data D#1 has not been received by the receiving station (RX), and sets data D#1 to be retransmitted.

[0193] In the retransmission process of data D#1, the link management unit LM of the transmitting station TX inputs data D#1 to the STA1 of the transmitting station TX (step S112). Note that in Figure 21, steps S75 to S83 are executed after the process in step S112.

[0194] Then, STA1 of the transmitting station TX transmits A-MPDU[D#1], which includes the MPDU containing data D#1, to STA1 of the receiving station RX (step S113).

[0195] In this example, STA1 of the receiving station RX, which received A-MPDU[D#1], does not detect an error in the MPDU containing data D#1. In this case, STA1 of the receiving station RX inputs the data D#1 received from the transmitting station TX to the link management unit LM of the receiving station RX (step S114). Then, the link management unit LM of the receiving station RX updates the received bitmap RBM based on this reception result and stores data D#1 in the sorting buffer unit 423.

[0196] Then, as in the first embodiment, the processing in steps S86 to S91 is performed. That is, after the retransmission process, the transmitting station TX sends a BlockAck request and the receiving station RX sends a BlockAck. After that, the transmitting station TX completes the transmission of data D#1 to D#4 to the receiving station RX in response to the fact that data D#1, D#2, D#3 and D#4 stored in the transmission buffer control unit 413 have been erased.

[0197] <2-2> Effects of the second embodiment As described above, in the wireless communication system 1 according to the second embodiment, the link management unit LM of the transmitting station TX queries each STA function for the data transmission status before executing the retransmission process. The link management unit LM of the transmitting station TX then excludes the untransmitted data confirmed by the query and determines the data to be retransmitted. As a result, the wireless communication system 1 according to the second embodiment can omit the transmission of duplicate data, i.e., data that has already been received by the receiving station RX, during the retransmission process. Consequently, the wireless communication system 1 according to the second embodiment can improve the efficiency of data communication compared to the first embodiment.

[0198] <3> others In the above embodiment, each STA function may notify the corresponding link management unit LM if the link cannot be maintained due to movement of the wireless terminal device WTA or the like. The link management unit LM2 of the wireless terminal device WTA may also change the multilink status with the link management unit LM1 of the base station AP based on the notification from the STA function. Specifically, for example, the link management unit LM2 of the wireless terminal device WTA and the link management unit LM1 of the base station AP may appropriately change the STA function used for multilink. When the multilink status is changed, the link management units LM1 and LM2 update the link management information 51a and 51b, respectively. The link management units LM1 and LM2 may also update the association between traffic and STA functions in accordance with the increase or decrease in the number of links.

[0199] The configuration and functional configuration of the information communication system 1 according to this embodiment may be other configurations. For example, the example given is that each of the base station AP and the wireless terminal device WTA has three STA functions (radio signal processing units), but it is not limited to this. The base station AP only needs to have at least two radio signal processing units. Similarly, the wireless terminal device WTA only needs to have at least two radio signal processing units. The number of channels that each STA function can process can be appropriately set according to the frequency band used. Each of the wireless communication modules 13 and 23 may support wireless communication in multiple frequency bands by using multiple communication modules, or it may support wireless communication in multiple frequency bands with a single communication module. Furthermore, the functional configuration of the base station AP and the wireless terminal device WTA may have other names and groupings as long as they can perform the operations described in the embodiment.

[0200] In the information communication system 1 according to this embodiment, the CPU 10 provided in the base station AP and the CPU 20 provided in the wireless terminal device WTA may be other circuits. For example, the base station AP and the wireless terminal device WTA may each be equipped with an MPU (Micro Processing Unit) or the like instead of a CPU. Each of the processes described in the embodiment may be implemented by dedicated hardware. The processes of the base station AP and the wireless terminal device WTA may be a mixture of processes executed by software and processes executed by hardware, or they may consist of only one or the other.

[0201] In the embodiments, the flowchart used to describe the operation is merely an example. The order of each operation described in the embodiments may be rearranged to the extent possible, and other processes may be added. Also, the wireless frame format described in the embodiments is merely an example. In the information communication system 1, other formats may be used as long as it is possible to perform the operations described in the embodiments.

[0202] In this specification, “MPDU” may also be called a data unit. When a transmitting station TX transmits traffic assigned to multiple links, a collection of MPDUs allocated to a certain STA function may be called a “data unit group.” The transmitting bitmap TBM and the receiving bitmap RBM may simply be called “information.” The transmitting bitmap TBM may be called “transmitted information.” The receiving bitmap RBM may be called “received information” or “delivered information.” The “sorting buffer unit 423” may simply be called the “buffer unit.” The sorting process in the sorting buffer unit 423 and the output of data to the third MAC processing unit 424 are performed, for example, based on the control of the management unit 50. The roles of “0” and “1” in each bitmap information may be reversed. A “BlockAck request” may be called a “request to send information indicating the sequence number SN of data that has been received by the receiving station RX,” or a “request to send the data reception status.”

[0203] "Transmitted" indicates the state of the bits in the transmit bitmap TBM corresponding to the sequence number SN of the data that has been confirmed to have been received by the receiving station RX. In other words, "transmitted data" corresponds to data that has been confirmed to have been received by the receiving station RX. "Received" indicates the state of the bits in the receive bitmap RBM corresponding to the sequence number SN of the data that the receiving station RX has successfully received. In other words, "data that has been received by the receiving station RX" corresponds to data that the receiving station RX has successfully corrected for errors in the data received from the transmitting station TX and stored in the sorting buffer 422. "Data that has not been received by the receiving station RX" corresponds to data that has not been indicated as received by the receive bitmap RBM.

[0204] Furthermore, the present invention is not limited to the embodiments described above, and can be modified in various ways during implementation without departing from its essence. Also, each embodiment may be combined as appropriate, and in that case, the combined effects can be obtained. Moreover, the above embodiments include various inventions, and various inventions can be extracted by selecting combinations from the multiple disclosed constituent elements. For example, if the problem can be solved and effects obtained even if some constituent elements are deleted from all the constituent elements shown in the embodiment, then the configuration with these deleted constituent elements can be extracted as an invention. [Explanation of symbols]

[0205] 1… Information and communication systems 10,20…CPU 11,21…ROM 12,22...RAM 13,23… Wireless communication module 14…Wired communication module 24…Display 25…Storage 30...Data Processing Unit 40…MAC frame processing unit 411...Data Categorization Department 412...1st MAC Processing Unit 413...Transmit Buffer Control Unit 414...Data Distribution Department 421... Reception Status Management Department 422...2nd MAC Processing Unit 423... Sorting buffer section 424...3rd MAC Processing Unit 50…Management Department 60... Wireless signal processing unit 610... Frame generation unit 611...Storage section 612... Transmitter / Receiver 613... Frame Processing Unit 620... Transmitter / Receiver 621... Frame Processing Unit 622... Reception success / failure determination unit 623... Frame generation unit 70…Application execution unit LM1, LM2… Link Management Department BS…Base station WTA... Wireless Terminal Device TX…Transmission station RX...receiving station SN...Sequence number RBM…Received Bitmap TBM…Transmit Bitmap SSN...Start Sequence Number BMI…Bitmap information

Claims

1. A first wireless signal processing unit configured to transmit a wireless signal using a first channel, A second wireless signal processing unit configured to transmit wireless signals using a second channel different from the first channel, The system comprises a first wireless signal processing unit and a buffer unit that stores data transmitted to a receiving station using the second wireless signal processing unit, A multilink is established with the receiving station using the first wireless signal processing unit and the second wireless signal processing unit. When the buffer unit receives predetermined information indicating the sequence number of data that has been received by the receiving station from the receiving station via the first radio signal processing unit or the second radio signal processing unit, it discards the data stored in the buffer unit that corresponds to the sequence number indicated by the predetermined information, and sets the reception status of the data to "transmitted". The buffer unit, based on the predetermined information, instructs the first wireless signal processing unit or the second wireless signal processing unit to transmit to the receiving station any data stored in the buffer unit that has not yet been received. Transmitting station.

2. The buffer unit, when instructing the first wireless signal processing unit or the second wireless signal processing unit to transmit the unreceived data, queries the first wireless signal processing unit and the second wireless signal processing unit to check for the presence of untransmitted data on the multilink, and then transmits the unreceived data to the receiving station, excluding the sequence numbers of the untransmitted data confirmed by the query. The transmitting station according to claim 1.

3. The buffer unit periodically sends a request to the receiving station to transmit information indicating the sequence number of the data that has been received by the receiving station. A transmitting station according to either claim 1 or claim 2.

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