Base stations and terminals

Abstract

To provide base stations and terminals that improve the quality of multilink communication. [Solution] In the wireless system, the base station (10) includes first and second wireless signal processing units and a link management unit. The first and second wireless signal processing units transmit and receive wireless signals using first and second channels, respectively. The link management unit establishes a multilink with a terminal (20) using the first and second wireless signal processing units (links #1 and #2), sets an anchor link used for transmitting and receiving control information related to the operation of the multilink, transmits a first wireless frame to the terminal requesting a change of anchor link using the first wireless signal processing unit set on the anchor link, and after transmitting the first wireless frame, if either the first or second wireless signal processing unit receives an acknowledgment from the terminal, changes the anchor link from the first wireless signal processing unit to the second wireless signal processing unit.

Description

Technical Field

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

Background Art

[0002] As a wireless system for wirelessly connecting a base station and a terminal, 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 communication quality of multi-link.

Means for Solving the Problems

[0005] The base station of the embodiment includes a first radio signal processing unit, a second radio signal processing unit, and a link management unit. The first radio signal processing unit is configured to transmit and receive radio signals using a first channel. The second radio signal processing unit is configured to transmit and receive radio signals using a second channel different from the first channel. The link management unit establishes a multilink with a terminal using the first radio signal processing unit and the second radio signal processing unit, and sets an anchor link used for transmitting and receiving control information related to the operation of the multilink. The link management unit uses the first radio signal processing unit set on the anchor link to send a first radio frame to the terminal requesting a change of anchor link, and after the first radio frame has been transmitted, if either the first radio signal processing unit or the second radio signal processing unit receives an acknowledgment from the terminal, it changes the anchor link from the first radio signal processing unit to the second radio signal processing unit. [Effects of the Invention]

[0006] The base station of this embodiment can improve the communication quality of multilinks. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a conceptual diagram showing an example of the overall configuration of a wireless system according to the embodiment. [Figure 2] Figure 2 is a conceptual diagram showing an example of a frequency band used for wireless communication in the wireless system according to the embodiment. [Figure 3] Figure 3 is a conceptual diagram showing an example of the format of a wireless frame in the wireless system according to this embodiment. [Figure 4] Figure 4 is a block diagram showing an example of the configuration of a base station included in the wireless system according to the embodiment. [Figure 5] Figure 5 is a block diagram showing an example of the functions of a base station equipped with the wireless system according to the embodiment. [Figure 6] Figure 6 is a block diagram showing an example of the configuration of a terminal in a wireless system according to the embodiment. [Figure 7] Figure 7 is a block diagram showing an example of the functions of a terminal in the wireless system according to the embodiment. [Figure 8] Figure 8 is a block diagram showing an example of a detailed function of the link management unit of a base station equipped with a wireless system according to the embodiment. [Figure 9] Figure 9 is a table showing an example of link management information in a wireless system according to this embodiment. [Figure 10] Figure 10 is a flowchart showing an example of multilink processing in a wireless system according to an embodiment. [Figure 11] Figure 11 is a conceptual diagram showing an example of a method for outputting a beacon signal at a base station of a wireless system according to an embodiment. [Figure 12] Figure 12 is a conceptual diagram showing an example of a beacon signal including multilink capability information in a wireless system according to an embodiment. [Figure 13] Figure 13 is a flowchart showing an example of a data transmission method during multilink operation in a wireless system according to the embodiment. [Figure 14] Figure 14 is a flowchart showing an example of the execution conditions for the anchor link change process in the wireless system according to the embodiment. [Figure 15] Figure 15 is a flowchart showing a specific example of anchor link change processing in a wireless system according to an embodiment. [Figure 16] Figure 16 is a conceptual diagram showing a specific example of a wireless frame used in the anchor link change process of the wireless system according to the embodiment. [Figure 17] Figure 17 is a conceptual diagram showing a specific example of a wireless frame used in the anchor link change process of the wireless system according to the embodiment. [Figure 18] Figure 18 is a conceptual diagram showing an example of a method for obtaining communication quality measurement results by a base station equipped with a wireless system according to the embodiment. [Figure 19] Figure 19 is a conceptual diagram showing an example of a method for obtaining communication quality measurement results by a base station of a wireless system according to the embodiment. [Figure 20] FIG. 20 is a flowchart showing an example of a method for acquiring communication quality measurement results by a base station included in a wireless system according to an embodiment. [Figure 21] FIG. 21 is a conceptual diagram showing an example of a method for notifying communication quality measurement results by a terminal included in a wireless system according to an embodiment. [Figure 22] FIG. 22 is a conceptual diagram showing an example of a method for notifying communication quality measurement results by a terminal included in a wireless system according to an embodiment. [Figure 23] FIG. 23 is a flowchart showing an example of a method for notifying communication quality measurement results by a terminal included in a wireless system according to an embodiment. [Figure 24] FIG. 24 is a conceptual diagram showing an example of an overall configuration of a wireless system according to a modification of an embodiment. [Figure 25] FIG. 25 is a table showing a combination of a link set of a multi-link and setting of an anchor link used in a wireless system according to a modification of an embodiment. [Figure 26] FIG. 26 is a table showing an example of link management information in a wireless system according to a first modification of an embodiment. [Figure 27] FIG. 27 is a flowchart showing a specific example of anchor link change processing in a wireless system according to a first modification of an embodiment. [Figure 28] FIG. 28 is a table showing an example of link management information in a wireless system according to a second modification of an embodiment. [Figure 29] FIG. 29 is a flowchart showing a first example of multi-link processing in a wireless system according to a second modification of an embodiment. [Figure 30] FIG. 30 is a flowchart showing a second example of multi-link processing in a wireless system according to a second modification of an embodiment. [Figure 31] FIG. 31 is a table showing an example of link management information in a wireless system according to a third modification of an embodiment. [Figure 32]Figure 32 is a conceptual diagram showing an example of a method for outputting a beacon signal at a base station of a wireless system according to a third modified embodiment. [Figure 33] Figure 33 is a table showing an example of link management information in a wireless system according to a fourth modified embodiment. [Figure 34] Figure 34 is a flowchart showing an example of anchor link change processing in a wireless system according to a fourth modified embodiment. [Modes for carrying out the invention]

[0008] The following describes a wireless system 1 according to an embodiment, with reference to the drawings. The embodiments illustrate devices and methods for realizing the technical idea of ​​the invention. The drawings are schematic or conceptual. The dimensions and proportions of each drawing are not necessarily the same as those of reality. The technical idea of ​​the present invention is not defined by the shape, structure, arrangement, etc. of the components. In the following description, components having substantially the same function and configuration are denoted by the same reference numerals.

[0009] <1> Configuration of Wireless System 1 <1-1> Overall configuration of wireless system 1 Figure 1 shows an example of the configuration of a wireless system 1 according to an embodiment. As shown in Figure 1, the wireless system 1 includes, for example, a base station 10, a terminal 20, and a server 30.

[0010] Base station 10 is connected to a network NW and used as a wireless LAN access point. For example, base station 10 can wirelessly distribute data received from the network NW to terminal 20. Base station 10 can also connect to terminal 20 using one or more types of bandwidths. In this specification, a wireless connection between base station 10 and terminal 20 using multiple types of bandwidths is referred to as "multilink". Communication between base station 10 and terminal 20 is based on, for example, the IEEE 802.11 standard.

[0011] Terminal 20 is, for example, a wireless terminal such as a smartphone or tablet PC. Terminal 20 can send and receive data to and from a server 30 on the network NW via a wirelessly connected base station 10. Terminal 20 may also be other electronic devices such as a desktop computer or laptop computer. Terminal 20 only needs to be a device that can communicate with at least the base station 10 and can perform the operations described later.

[0012] Server 30 is capable of holding various types of information, for example, it holds content data targeted to terminal 20. Server 30 is configured to be connected to a network NW via a wired connection and to be able to communicate with base station 10 via the network NW. It is sufficient that server 30 can communicate with at least base station 10. In other words, communication between base station 10 and server 30 may be wired or wireless.

[0013] In the wireless system 1 according to this embodiment, data communication between the base station 10 and the terminal 20 is based on 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).

[0014] The data link layer includes, for example, the LLC (Logical Link Control) layer and the MAC (Media Access Control) layer. The LLC layer adds headers such as DSAP (Destination Service Access Point) and SSAP (Source Service Access Point) 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] (Regarding the frequency bands used for wireless communication) Figure 2 shows an example of frequency bands used for wireless communication in the wireless system 1 according to this embodiment. As shown in Figure 2, for example, the 2.4GHz band, 5GHz band, and 6GHz band are used for wireless communication. Each frequency band contains multiple channels. In this example, each of the 2.4GHz band, 5GHz band, and 6GHz band contains at least three channels CH1, CH2, and CH3. Communication using each channel CH is realized by the STA function described later.

[0016] Furthermore, wireless system 1 may use frequency bands other than the 2.4GHz, 5GHz, and 6GHz bands for wireless communication. Each frequency band only needs to have at least one channel CH configured. For multilink, channels CH from the same frequency band may be used, or channels CH from different frequency bands may be used.

[0017] (Regarding the wireless frame format) Figure 3 shows a specific example of the format of a wireless frame used for communication between a base station 10 and a terminal 20 in a wireless system 1 according to an embodiment. As shown in Figure 3, fields included in a wireless frame include, for example, a Frame Control field, a Duration field, an Address1 field, an Address2 field, an Address3 field, a Sequence Control field, other control information fields, a Frame Body field, and an FCS (Frame Check Sequence) field. These fields may or may not be included depending on the type of wireless frame.

[0018] The Frame Control field and other control information fields correspond to, for example, the MAC header included in the MAC frame. The Frame Body field corresponds to, for example, the MAC payload included in the MAC frame. The FCS field stores the error detection code between the MAC header and the Frame Body field and is used to determine whether or not there is an error in the wireless frame.

[0019] The Frame Control field displays various control information, including, for example, the Type value, Subtype value, To DS (To Distribution System) value, and From DS 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.

[0020] The content of a wireless frame changes depending on the combination of Type and Subtype values. 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" indicates that the data frame is directed from an external source to the DS (Distribution System). "01" indicates that the data frame is destined to go outside the DS. "11" is used when configuring a mesh network.

[0021] The Duration field indicates the planned duration of use of the wireless connection. Multiple Address fields indicate the BSSID, source address, destination address, sender terminal address, receiver terminal address, etc. The Sequence Control field indicates the sequence number of the MAC frame and the fragment number for fragments. Other control information fields include, for example, Traffic Type (TID) information. TID information may be inserted at other locations within the wireless frame. The Frame Body field contains information specific to the frame type. For example, the Frame Body field stores data when it corresponds to a data frame.

[0022] <1-2> Configuration of base station 10 Figure 4 shows an example of the configuration of a base station 10 included in the wireless system 1 according to the embodiment. As shown in Figure 4, the base station 10 includes, for example, a CPU (Central Processing Unit) 11, ROM (Read Only Memory) 12, RAM (Random Access Memory) 13, a wireless communication module 14, and a wired communication module 15.

[0023] The CPU 11 is a circuit capable of executing various programs and controls the overall operation of the base station 10. The ROM 12 is a non-volatile semiconductor memory that holds programs and control data for controlling the base station 10. The RAM 13 is, for example, a volatile semiconductor memory and is used as a workspace for the CPU 11. The wireless communication module 14 is a circuit used for transmitting and receiving data via wireless signals and is connected to an antenna. The wireless communication module 14 also includes, for example, multiple communication modules corresponding to multiple frequency bands. The wired communication module 15 is a circuit used for transmitting and receiving data via wired signals and is connected to a network NW.

[0024] Figure 5 shows an example of the functional configuration of a base station 10 in a wireless system 1 according to an embodiment. As shown in Figure 5, the base station 10 includes, for example, a data processing unit 100, a MAC frame processing unit 110, a management unit 120, and wireless signal processing units 130, 140, and 150. The processing of the data processing unit 100, MAC frame processing unit 110, management unit 120, and wireless signal processing units 130, 140, and 150 is realized, for example, by a CPU 11 and a wireless communication module 14.

[0025] The data processing unit 100 can perform LLC layer processing and higher layer processing on the input data. For example, the data processing unit 100 outputs data input from the server 30 via the network NW to the MAC frame processing unit 110. The data processing unit 100 also sends data input from the MAC frame processing unit 110 to the server 30 via the network NW.

[0026] The MAC frame processing unit 110 performs, for example, a portion of the MAC layer processing on the input data. For example, the MAC frame processing unit 110 generates a MAC frame from the data input from the data processing unit 100. The MAC frame generation unit 110 also reconstructs data from the MAC frames input from the wireless signal processing units 130, 140, and 150, respectively. The process of generating a MAC frame from data and the process of reconstructing data from a MAC frame are based, for example, on the IEEE 802.11 standard.

[0027] The management unit 120 manages the link with the terminal 20 based on notifications received from the radio signal processing units 130, 140, and 150 via the MAC frame processing unit 110. The management unit 120 includes link management information 121. The link management information 121 is stored, for example, in RAM 13 and includes information about the terminal 20 that is wirelessly connected to the base station 10. The management unit 120 also includes an association processing unit 122, an authentication processing unit 123, and a quality measurement unit 124. The association processing unit 122 executes an association protocol when it receives a connection request from the terminal 20 via any of the radio signal processing units 130, 140, and 150. The authentication processing unit 123 executes an authentication protocol following the connection request. The quality measurement unit 124 periodically measures and evaluates the communication quality of each channel. The quality measurement unit 124 also periodically requests the terminal 20 to measure and report the communication quality. Hereinafter, the set consisting of the data processing unit 100, the MAC frame processing unit 110, and the management unit 120 will be referred to as the link management unit LM1 of the base station 10.

[0028] Each of the wireless signal processing units 130, 140, and 150 transmits and receives data between the base station 10 and the terminal 20 using wireless communication. For example, each of the wireless signal processing units 130, 140, and 150 adds a preamble, PHY header, etc., to the data input from the MAC frame processing unit 110 to create a wireless frame. Then, each of the wireless signal processing units 130, 140, and 150 converts the wireless frame into a wireless signal and distributes the wireless signal via the antenna of the base station 10. In addition, each of the wireless signal processing units 130, 140, and 150 converts the wireless signal received via the antenna of the base station 10 into a wireless frame. Then, each of the wireless signal processing units 130, 140, and 150 outputs the data contained in the wireless frame (e.g., a MAC frame) to the MAC frame processing unit 110.

[0029] Thus, each of the wireless signal processing units 130, 140, and 150 can perform, for example, part of the MAC layer processing and the first layer processing on the input data or wireless signal. For example, the wireless signal processing unit 130 handles wireless signals in the 2.4 GHz band. The wireless signal processing unit 140 handles wireless signals in the 5 GHz band. The wireless signal processing unit 150 handles wireless signals in the 6 GHz band. The wireless signal processing units 130, 140, and 150 may or may not share the antenna of the base station 10.

[0030] <1-3> Configuration of terminal 20 Figure 6 shows an example of the configuration of a terminal 20 included in the wireless system 1 according to the embodiment. As shown in Figure 6, the terminal 20 includes, for example, a CPU 21, ROM 22, RAM 23, a wireless communication module 24, a display 25, and storage 26.

[0031] The CPU 21 is a circuit capable of executing various programs and controls the overall operation of the terminal 20. The ROM 22 is a non-volatile semiconductor memory that holds programs and control data for controlling the terminal 20. The RAM 23 is, for example, a volatile semiconductor memory and is used as the working area for the CPU 21. The wireless communication module 24 is a circuit used for sending and receiving data via wireless signals and is connected to an antenna. The wireless communication module 24 also includes, for example, multiple communication modules corresponding to multiple frequency bands. The display 25 displays, for example, a GUI (Graphical User Interface) corresponding to application software. The display 25 may also function as an input interface for the terminal 20. The storage 26 is a non-volatile storage device that holds, for example, the system software of the terminal 20. Note that the terminal 20 does not necessarily have a display. For example, in an IoT terminal, the display 25 may be omitted.

[0032] Figure 7 shows an example of the functional configuration of a terminal 20 in a wireless system 1 according to an embodiment. As shown in Figure 7, the terminal 20 includes, for example, a data processing unit 200, a MAC frame processing unit 210, a management unit 220, wireless signal processing units 230, 240 and 250, and an application execution unit 260. The processing of the data processing unit 200, MAC frame processing unit 210, management unit 220, and wireless signal processing units 230, 240 and 250 is realized, for example, by a CPU 21 and a wireless communication module 24. The processing of the application execution unit 260 is realized, for example, by the CPU 21.

[0033] The data processing unit 200 can perform LLC layer processing and higher layer (layers 3 to 7) processing on the input data. For example, the data processing unit 200 outputs data input from the application execution unit 260 to the MAC frame processing unit 210. Also, the data processing unit 200 outputs data input from the MAC frame processing unit 210 to the application execution unit 260.

[0034] The MAC frame processing unit 210 performs, for example, a portion of the MAC layer processing on the input data. For example, the MAC frame processing unit 210 generates a MAC frame from the data input from the data processing unit 200. The MAC frame processing unit 210 also reconstructs data from the MAC frames input from the wireless signal processing units 230, 240, and 250, respectively. The process of generating a MAC frame from data and the process of reconstructing data from a MAC frame are based, for example, on the IEEE 802.11 standard.

[0035] The management unit 220 manages the link with the base station 10 based on notifications received from the radio signal processing units 230, 240, and 250 via the MAC frame processing unit 210. The management unit 220 includes link management information 221. The link management information 221 is stored, for example, in RAM 23 and includes information about the base station 10 that is wirelessly connected to the terminal 20. The management unit 220 also includes an association processing unit 222, an authentication processing unit 223, and a quality measurement unit 224. The association processing unit 222 executes an association protocol when it receives a connection response from the base station 10 via any of the radio signal processing units 230, 240, and 250. The authentication processing unit 223 executes an authentication protocol following the connection response. The quality measurement unit 224 periodically measures and evaluates the communication quality of each channel. Furthermore, the quality measurement unit 224 responds to requests for measurement and notification of communication quality received from the base station 10 by measuring the communication quality using each STA function and notifying the base station 10 of the measurement results. Hereinafter, the set of data processing unit 200, MAC frame processing unit 210, and management unit 220 will be referred to as the link management unit LM2 of the terminal 20.

[0036] Each of the wireless signal processing units 230, 240, and 250 transmits and receives data between the base station 10 and the terminal 20 using wireless communication. For example, each of the wireless signal processing units 230, 240, and 250 adds a preamble, PHY header, etc., to the data input from the MAC frame processing unit 210 to create a wireless frame. Then, each of the wireless signal processing units 230, 240, and 250 converts the wireless frame into a wireless signal and distributes the wireless signal via the antenna of the terminal 20. In addition, each of the wireless signal processing units 230, 240, and 250 converts the wireless signal received via the antenna of the terminal 20 into a wireless frame. Then, each of the wireless signal processing units 230, 240, and 250 outputs the data contained in the wireless frame (e.g., a MAC frame) to the MAC frame processing unit 210.

[0037] Thus, each of the wireless signal processing units 230, 240, and 250 can perform, for example, part of the MAC layer processing and the first layer processing on the input data or wireless signal. For example, the wireless signal processing unit 230 handles wireless signals in the 2.4 GHz band. The wireless signal processing unit 240 handles wireless signals in the 5 GHz band. The wireless signal processing unit 250 handles wireless signals in the 6 GHz band. The wireless signal processing units 230, 240, and 250 may or may not share the antenna of the terminal 20.

[0038] The application execution unit 260 executes an application that can utilize the data input from the data processing unit 210. For example, the application execution unit 260 can display application information on the display 25. Furthermore, the application execution unit 260 can operate based on the operation of the input interface.

[0039] In the wireless system 1 according to the embodiment described above, the wireless signal processing units 130, 140, and 150 of the base station 10 are configured to be connectable to the wireless signal processing units 230, 240, and 250 of the terminal 20, respectively. That is, wireless connection between wireless signal processing units 130 and 230 can be made using the 2.4GHz band. Wireless connection between wireless signal processing units 140 and 240 can be made using the 5GHz band. Wireless connection between wireless signal processing units 150 and 250 can be made using the 6GHz band. In this specification, each wireless signal processing unit may be referred to as an "STA function". That is, the wireless system 1 according to the embodiment has multiple STA functions.

[0040] <1-4> About the Link Management Unit LM1 Figure 8 shows details of the channel access function in the link management unit LM1 of the base station 10 of the wireless system 1 according to the embodiment. Note that the function of the link management unit LM2 of the terminal 20 is the same as that of the link management unit LM1 of the base station 10, so its explanation is omitted. As shown in Figure 8, the link management unit LM1 includes, for example, a data categorization unit 125, transmission queues 126A, 126B, 126C, 126D and 126E, CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance) execution units 127A, 127B, 127C, 127D and 127E, and a data collision management unit 128.

[0041] The data categorization unit 125 categorizes the data input from the data processing unit 100. Examples of data categories include "LL (Low Latency)", "VO (Voice)", "VI (Video)", "BE (Best Effort)", and "BK (Background)". LL is applied to data requiring low latency. Therefore, it is preferable that LL data be processed with priority over any of the VO, VI, BE, and BK data.

[0042] The data categorization unit 125 then inputs the categorized data into one of the transmission queues 126A, 126B, 126C, 126D, and 126E. Specifically, LL data is input into transmission queue 126A, VO data into transmission queue 126B, VI data into transmission queue 126C, BE data into transmission queue 126D, and BK data into transmission queue 126E. The data of each input category is then stored in the corresponding transmission queue 126A through E.

[0043] Each of the CSMA / CA execution units 127A, 127B, 127C, 127D, and 127E waits for a time specified by pre-configured access parameters, while confirming through carrier sensing that no other terminals are transmitting wireless signals in CSMA / CA. Then, each of the CSMA / CA execution units 127A, 127B, 127C, 127D, and 127E retrieves data from the transmission queues 126A, 126B, 126C, 126D, and 126E, respectively, and outputs the retrieved data to at least one of the wireless signal processing units 130, 140, and 150 via the data collision management unit 128. The wireless signal containing this data is then transmitted by the wireless signal processing unit (STA function) for which transmission rights have been acquired by CSMA / CA.

[0044] CSMA / CA execution unit 127A performs CSMA / CA on the LL data held in the transmission queue 126A. CSMA / CA execution unit 127B performs CSMA / CA on the VO data held in the transmission queue 126B. CSMA / CA execution unit 127C performs CSMA / CA on the VI data held in the transmission queue 126C. CSMA / CA execution unit 127D performs CSMA / CA on the BE data held in the transmission queue 126D. CSMA / CA execution unit 127E performs CSMA / CA on the BK data held in the transmission queue 126E.

[0045] Access parameters are assigned in the order of priority for radio signal transmission, for example, LL, 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, for transmission queue 126, the shorter the CWmin and CWmax, the easier it is to obtain transmission rights. The priority of transmission queue 126 is higher as the AIFS is smaller. The amount of data transmitted in a single transmission right is greater as the value of TXOPLimit is larger.

[0046] The data collision management unit 128 prevents data collisions when multiple CSMA / CA execution units 127 acquire transmission rights with the same STA function. Specifically, the data collision management unit 128 adjusts the transmission timing of data from different categories that have acquired transmission rights with the same STA function, and transmits data from the category with higher priority to the STA function first. For example, an STA function that has acquired transmission rights through CSMA / CA in transmission queue 126A of LL may acquire transmission rights at the same time as an STA function that has acquired transmission rights through CSMA / CA in any of the other transmission queues 126B to 126E. In this case, the data collision management unit 128 prioritizes transmitting the data stored in transmission queue 126A to the STA function. Similarly, in other combinations of transmission queues 126, data is transmitted in an order based on the priority set for each category. This prevents collisions between data that have been assigned to transmit to the same STA function.

[0047] In this embodiment, the link management units LM1 and LM2 implement the channel access function, but each STA function may also implement the channel access function. When the link management units LM1 and LM2 implement the channel access function, each STA function detects the state of the radio channel (idle / busy) in the corresponding link, and the link management units LM1 and LM2 determine whether or not to transmit data (which link to use for transmission, etc.). On the other hand, when each STA function implements the channel access function, each STA function can independently perform carrier sensing and transmit data. In this case, channel access when multiple links are used simultaneously may be performed by commonizing access parameters through communication between multiple STA functions, or by commonizing access parameters by the link management units LM1 and LM2. The base station 10 and terminal 20 can use multiple links simultaneously by transmitting data between multiple STA functions based on common access parameters.

[0048] <1-5> About Link Management Information 121 Figure 9 shows an example of link management information 121 in the wireless system 1 according to the embodiment. Note that the link management information 221 of the terminal 20 contains similar information to the link management information 121 of the base station 10, so its explanation is omitted. As shown in Figure 9, the link management information 121 includes information such as STA function, frequency band, channel ID, link destination ID, multilink, and TID.

[0049] In this example, “STA1” corresponds to the STA function using the 6GHz frequency band, i.e., the wireless signal processing unit 150 or 250. “STA2” corresponds to the STA function using the 5GHz frequency band, i.e., the wireless signal processing unit 140 or 240. “STA3” corresponds to the STA function using the 2.4GHz frequency band, i.e., the wireless signal processing unit 130 or 230. Hereafter, STA1, STA2, and STA3 will also be referred to as Link #1, Link #2, and Link #3, respectively.

[0050] The channel ID corresponds to the identifier of the channel used in the configured frequency band. The link destination ID corresponds to the identifier of terminal 20 in link management information 121 and to the identifier of base station 10 in link management information 221. In this example, a multilink is established using STA1, STA2, and STA3. When a multilink is established, link management units LM1 and LM2 each transmit data input from the upper layer using the link of at least one STA function associated with the multilink.

[0051] The base station 10 sets one of its multiple STA functions as the anchor link. In this example, STA1 is set as the anchor link. The anchor link is set by the link management unit LM1 of the base station 10. In addition to sending and receiving assigned data, the anchor link sends and receives control information related to the operation of the multilink. Note that the combination of links constituting the multilink may differ among the multiple terminals 20, each of which has established a multilink with the base station 10.

[0052] The “TID” in the link management information 121 indicates the association between an STA function and TID information. Each STA function sends and receives data corresponding to the assigned TID information. For example, TID#1 to 4 each correspond to one of LL, VO, VI, BE, or BK. One STA function may be associated with one traffic, i.e., one TID information, or multiple STA functions may be associated with it. In this example, TID#1 is assigned to both STA1 and STA2. TID#2 is assigned to STA1. TID#3 is assigned to STA2. TID#4 is assigned to STA3.

[0053] Traffic flows corresponding to such associations between traffic and STA functions are pre-configured during the setup of the multilink between the base station 10 and the terminal 20. For example, the link management unit LM2 of the terminal 20 determines the association between traffic and STA functions and requests it from the link management unit LM1 of the base station 10. The base station 10 then responds to the request, thereby confirming the association between traffic and STA functions.

[0054] Furthermore, traffic is set to be evenly distributed across multiple links that constitute a multilink, for example. However, it is not limited to this, and similar types of traffic (e.g., priority / non-priority) may be grouped together on one of the links that constitute the multilink. In addition, as for the association between STA functions and traffic, for example, audio may be associated with the 2.4GHz frequency band, and video with 5G. In this way, it is preferable that the frequencies used for transmission and reception are allocated according to the type of information and data capacity being handled.

[0055] <2> Operation of Wireless System 1 The following describes some examples of various operations related to multilink in the wireless system 1 according to this embodiment. For the sake of brevity, in the following description, STA1, STA2, and STA3 of the base station 10 will also be referred to as "access point APs". The transmission of radio signals from STA1, STA2, and STA3 of the terminal 20 to the access point APs corresponds to the transmission of radio signals to STA1, STA2, and STA3 of the base station 10, respectively. When STA1, STA2, and STA3 are mentioned individually, they refer to the STA functions of the terminal 20.

[0056] <2-1> Multilink Processing Figure 10 shows an example of the multilink processing flow in the wireless system 1 according to the embodiment. As shown in Figure 10, in the multilink processing, for example, steps S10 to S16 are executed in order. The following describes the processes of steps S10 to S16 using the case where a multilink is formed using three STA functions as an example.

[0057] In step S10, terminal 20 sends a probe request to base station 10. The probe request is a signal to confirm whether or not base station 10 is present in the vicinity of terminal 20. The Frame Control field of the probe request contains, for example, “00 / 0100 (Type value / Subtype value)”. When base station 10 receives the probe request, it executes the process in step S11.

[0058] In step S11, the base station 10 sends a probe response to the terminal 20. The probe response is a signal that the base station 10 uses to respond to a probe request from the terminal 20. The Frame Control field of the probe response contains, for example, “00 / 0101 (Type value / Subtype value)”. When the terminal 20 receives the probe response, it executes the process in step S12.

[0059] In step S12, terminal 20 sends a multilink association request to base station 10 via at least one STA function. The multilink association request is a signal requesting base station 10 to establish a multilink. For example, the multilink association request is generated by the link management unit LM2 of terminal 20. The Frame Control field of the multilink association request contains, for example, “00 / xxxx(Type value / Subtype value (xxxx is a predetermined number))”. When the link management unit LM1 of base station 10 receives the multilink association request, it executes the process in step S13.

[0060] In step S13, the link management unit LM1 of the base station 10 performs a multilink association process using one STA function. Specifically, the base station 10 first performs the association process for the first STA function with the terminal 20. Then, once a wireless connection (link) is established with the first STA function, the link management unit LM1 of the base station 10 uses the first STA function, which has an established link, to perform the association processes for the second STA function and the third STA function. In other words, an STA function with an established link is used for the association process of an STA function for which a link has not yet been established. Once the association processes for at least two STA functions are completed, the base station 10 establishes a multilink and performs the process in step S14.

[0061] In step S14, the link management unit LM1 of the base station 10 updates the link management information 121. In this example, step S14 is executed after two links have been established, but the link management information 121 may be updated each time the link status is updated, or it may be updated when a multilink is established. Once a multilink is established and the link management information is updated, the base station 10 executes step S15.

[0062] In step S15, the base station 10 sends a multilink establishment response to the terminal 20. The multilink establishment response is a signal used by the base station 10 to respond to a multilink request from the terminal 20. The Frame Control field of the multilink association request contains, for example, “00 / 0001 (Type value / Subtype value)”. The link management unit LM2 of the terminal 20 recognizes that a multilink has been established with the base station 10 based on the receipt of the multilink establishment response. Upon receiving the multilink establishment response, the terminal 20 executes the process in step S16.

[0063] In step S16, the link management unit LM2 of the terminal 20 updates the link management information 221. That is, the terminal 20 records in the link management information 221 that a multilink has been established with the base station 10. As a result, the multilink processing in the wireless system 1 according to the embodiment is completed, and data communication using the multilink becomes possible between the base station 10 and the terminal 20.

[0064] Furthermore, the wireless system 1 according to this embodiment may establish a multilink when establishing a link in the first STA function. In this case, the terminal 20 receives a multilink-related beacon signal from the base station 10 before the multilink association request in step S12. This operation will be explained below with reference to Figures 11 and 12.

[0065] Figure 11 shows an example of a method for outputting a beacon signal at a base station 10 of the wireless system 1 according to the embodiment. In this example, link #1 of links #1 to #3 is set as the anchor link. As shown in Figure 11, the base station 10 intermittently transmits the beacon signal using link #1, which is set as the anchor link. On the other hand, the transmission of beacon signals using links #2 and #3, which are not set as anchor links, is omitted. The beacon signal may be transmitted using links that are not set as anchor links, and it is sufficient that it is transmitted using at least the anchor link.

[0066] Figure 12 shows a specific example of a beacon signal containing multilink capability information in a wireless system 1 according to an embodiment. As shown in Figure 12, the beacon signal includes, for example, multilink capability information, operational information for link #1, operational information for link #2, and operational information for link #3. This information is generated by the link management unit LM1 of the base station 10.

[0067] The multilink capability information indicates whether base station 10 is capable of multilink. For example, if the multilink capability information is "0", it indicates that multilink is not possible. If the multilink capability information is "1", it indicates that multilink is possible. The link operation information (operational parameters) indicates the parameters for performing data transmission, etc., on links that may be used in multilink. For example, the operation information for link #1 indicates the EDCA (Enhanced Distributed Channel Access) access parameters for performing transmission control on that link.

[0068] When terminal 20 receives a beacon signal as explained using Figure 12, it checks the multilink capability information and operational information for each link to be multilinked from the beacon signal. Then, the link management unit LM2 of terminal 20 notifies the link management unit LM1 of base station 10 of information such as the links to be multilinked when a multilink association request is made. As a result, the link management unit LM1 of base station 10 can perform the association of multiple links specified by the link management unit LM2 of terminal 20 all at once and establish a multilink with terminal 20.

[0069] Furthermore, if the beacon signal described above is transmitted only over the anchor link, the beacon signal does not need to have a field indicating the anchor link. On the other hand, if the beacon signal is transmitted over both the anchor link and other links, the beacon signal may have a field indicating the anchor link and a field indicating the other links. The base station 10 may also add the information contained in the beacon signal described above to the probe response. In this case, the link management unit LM2 of the terminal 20 can send a multilink association request specifying the link to be used to the base station 10 without receiving the beacon signal. The base station 10 and the terminal 20 may also perform an authentication process when establishing a multilink.

[0070] <2-2> Data transfer during multilink Figure 13 shows an example of a data transmission method in multilink mode at a base station 10 of the wireless system 1 according to the embodiment. As shown in Figure 13, when the base station 10 acquires data from the upper layer, it sequentially executes the processes in steps S20 to S22. The processes in steps S20 to S22 are described below.

[0071] In step S20, the link management unit LM1 acquires TID information corresponding to the data. In other words, the link management unit LM1 associates the data with the TID by referring to control information such as a header attached to the data acquired from a higher layer.

[0072] In step S21, the link management unit LM1 acquires the STA function corresponding to the confirmed TID information. At this time, the link management unit LM1 confirms the association between the TID information and the STA function by referring to the link management information 121. The number of STA functions acquired by the link management unit LM1 in step S21 may be one or multiple.

[0073] In step S22, the link management unit LM1 outputs data to the acquired STA function. If one STA function is associated with the output data (traffic), the data is transmitted serially using that one STA function. On the other hand, if multiple STA functions are associated with the traffic, the data is transmitted in parallel using multiple STA functions.

[0074] Furthermore, when a single traffic is transmitted in parallel, data distribution and reordering are performed between the link management unit LM1 of the base station 10 and the link management unit LM2 of the terminal 20. Data distribution is performed by the transmitting link management unit LM, and data reordering is performed by the receiving link management unit LM. For example, the transmitting link management unit LM adds a flag indicating that it is a multilink and an identification number to the radio frame. The receiving link management unit LM then reorders the data based on the added flag and identification number.

[0075] Furthermore, in the wireless system 1 according to this embodiment, the link management unit LM may perform aggregation by combining multiple received data when it receives multiple data from a higher layer. Aggregation in multilink may be used as an optional function that can be selected by the user.

[0076] <2-3> About the process of changing anchor links The wireless system 1 according to this embodiment can change the anchor link based on predetermined conditions when using multilink. Hereinafter, the process by which the wireless system 1 changes the anchor link will be referred to as the "anchor link change process".

[0077] (Regarding the execution conditions for the anchor link modification process) First, an example of the execution conditions for the anchor link change process will be described. Figure 14 is a flowchart showing an example of the execution conditions for the anchor link change process in the wireless system 1 according to the embodiment. The link management unit LM1 of the base station 10 periodically executes the process shown in Figure 14 when multilink is in operation.

[0078] Specifically, the quality measurement unit 124 of the base station 10 obtains the communication quality measurement results for each link establishing a multilink from the quality measurement unit 224 of the terminal 20 (step S30). Then, the quality measurement unit 124 of the base station 10 evaluates the communication quality of each link based on the received communication quality measurement results (step S31). After that, the link management unit LM1 of the base station 10 checks whether the communication quality of the anchor link meets predetermined conditions (step S32).

[0079] If the communication quality of the anchor link meets the predetermined conditions (step S32, YES), the link management unit LM1 of the base station 10 terminates the process without changing the anchor link. On the other hand, if the communication quality of the anchor link does not meet the predetermined conditions (step S32, NO), the link management unit LM1 of the base station 10 checks whether the communication quality of the other links meets the predetermined conditions (step S33).

[0080] If the communication quality of the other links does not meet the predetermined conditions (step S33, NO), the link management unit LM1 of the base station 10 terminates the process without changing the anchor link. On the other hand, if the communication quality of the other links meets the predetermined conditions (step S33, YES), the link management unit LM1 of the base station 10 executes the anchor link change process (step S34). The link management unit LM1 of the base station 10 completes the process by changing the anchor link to one of the other links through the anchor link change process.

[0081] Various parameters can be used as evaluation criteria for the communication quality of each link. Furthermore, various methods can be used to measure communication quality. For example, the predetermined conditions in steps S32 and S33 may include channel utilization, the success rate of beacon signal reception, and the interference status of OBSS (Overlapping BSS). The predetermined conditions in step S32 and step S33 may be the same or different.

[0082] When channel utilization is used as a predetermined condition, the STA function of terminal 20 measures the busy time rate of each channel by carrier sense (CCA (Clear Channel Assessment) according to the IEEE 802.11 standard). The busy time rate corresponds to the percentage of time that the received power exceeds a certain threshold. The measurement results of the busy time rate of each channel are transmitted to the quality measurement unit 224. The quality measurement unit 124 of base station 10 then requests communication quality measurement and notification from terminal 20 and obtains the busy time rate measured by the quality measurement unit 224 of terminal 20. Then, the link management unit LM1 of base station 10 executes an anchor link change process if the busy time rate of the anchor link channels exceeds a predetermined threshold. In this anchor link change process, for example, the channel with the smallest busy time rate among the multiple channels that have established a multilink is determined to be the anchor link.

[0083] When the success rate of beacon signal reception is used as a predetermined condition, the base station 10 requests the terminal 20 to measure and notify the communication quality, and transmits beacon signals using multiple channels that have established a multilink over a predetermined period. The quality measurement unit 224 of the terminal 20 then measures the number of beacon signals successfully received for each channel during the predetermined period and reports the measurement results to the base station 10. Then, the link management unit LM1 of the base station 10 executes an anchor link change process if the ratio of the number of beacon signals transmitted to the number of beacon signals successfully received by the terminal 20 falls below a certain threshold. In this anchor link change process, for example, the channel that received the most beacon signals among the multiple channels that have established a multilink is determined to be the anchor link. If beacon signals are transmitted only on the anchor link, signals for communication quality measurement may be transmitted on other channels, and existing signals with known transmission cycles and transmission counts may be used.

[0084] When the interference status of OBSS is used as a predetermined condition, the quality measurement unit 124 of the base station 10 checks whether the OBSS interference on the anchor link is greater than the OBSS interference on the other links. In other words, the quality measurement unit 124 checks whether the channel occupancy time of OBSS on the anchor link is greater than the channel occupancy time of OBSS on the other links. Note that factors other than channel occupancy time may be used to evaluate interference, and it is sufficient that factors that make the channel busy during periods other than the exchange of BSS signals are used. For example, the magnitude of interference power, interference from other communication systems, or the presence of noise power may be used to evaluate interference.

[0085] In the above explanation, an example was given of a case where one parameter is used as a predetermined condition, but multiple parameters may be used as predetermined conditions. For example, the link management unit LM1 of the base station 10 may evaluate the communication quality of each link using both the channel utilization rate and the success rate of receiving beacon signals. For example, the link management unit LM1 of the base station 10 may perform an anchor link change process to change the anchor link to one of the other links if the success rate of receiving beacon signals falls below a predetermined threshold and the maximum value of the channel occupancy rate of OBSS of other links falls below a predetermined threshold.

[0086] (Specific example of anchor link modification process) Next, a specific example of the anchor link change process will be explained with reference to Figure 15. Figure 15 is a flowchart showing a specific example of the anchor link change process in the wireless system 1 according to the embodiment. Note that the initial state of the multilink in this example is set to the state shown in Figure 9. "Anchor" indicates that it is set as an anchor link. "Normal" indicates that it is a link that is not set as an anchor link. Hereafter, a link that is not set as an anchor link will be referred to as a "normal link".

[0087] As shown in Figure 15, when link #1 is the anchor link, the access point AP transmits a beacon signal using link #1, and the terminal 20 receives the beacon signal using the STA function assigned to link #1. The link management unit LM1 of the base station 10 periodically sends a communication quality measurement instruction to the terminal 20 to check the communication quality of the multilink. The communication quality measurement instruction is sent, for example, using the anchor link (link #1). Then, the quality measurement unit 224 of the terminal 20 measures the communication quality of each link constituting the multilink based on the receipt of the communication quality measurement instruction, and transmits the communication quality measurement results to the access point AP.

[0088] When the access point AP receives the communication quality measurement results, in this example, the link management unit LM1 of the base station 10 confirms that (1) the quality of the anchor link does not meet the predetermined conditions, (2) the quality of the other links meets the predetermined conditions, and (3) the link quality is link #2 > link #3. Then, the link management unit LM1 of the base station 10 sends an anchor link change instruction to the terminal 20 using the anchor link (link #1).

[0089] When terminal 20 receives an anchor link change instruction, the link management unit LM2 of terminal 20 transmits an acknowledgment ("OK") to terminal 20 via the anchor link if it can permit the anchor link change. On the other hand, if the link management unit LM2 of terminal 20 cannot permit the anchor link change, it transmits a negation ("NG") to base station 10 via the anchor link (not shown). When the link management unit LM2 of terminal 20 transmits the acknowledgment to the access point AP, it changes the anchor link of the multilink to link #2 and changes link #1 to the normal link. When the access point AP receives the acknowledgment of the anchor link change instruction from terminal 20, it transmits a beacon signal using the changed anchor link (link #2).

[0090] The anchor link change process described above is merely an example. The link management unit LM1 of the base station 10 should perform the anchor link change process based on the communication quality of each link constituting the multilink, and set a link with a higher communication quality than the current anchor link as the next anchor link. Alternatively, the link management unit LM1 of the base station 10 may change the anchor link to another link based on the fact that the communication quality of the anchor link has fallen below the communication quality of the other links, regardless of the communication quality status of the anchor link. "Acknowledgments" and "negative replies" may also be transmitted using links other than the anchor link.

[0091] (Regarding wireless frames used in anchor link modification processing) Figures 16 and 17 show specific examples of wireless frames used in the anchor link change process of the wireless system 1 according to the embodiment. Figure 16 corresponds to the wireless frame transmitted when the access point AP requests the terminal 20 to change the anchor link. Figure 17 corresponds to the wireless frame that the terminal 20 sends back to the access point AP in response to the request to change the anchor link.

[0092] As shown in Figure 16, the Frame Body of a wireless frame requesting an anchor link change includes, for example, a terminal identifier AID (Association Identifier), an anchor link change request, and the identifier of the target link to which the anchor link will be changed. The Link Management Unit LM2 of terminal 20 corresponding to the AID refers to the "identifier of the target link" based on the "anchor link change request" and determines whether or not an anchor link change is possible.

[0093] When it is possible to change the anchor link, the Frame Body of the wireless frame corresponding to the acknowledgment of the anchor link change request includes "OK" as shown in Figure 17(a). "OK" corresponds to a bit that indicates that the anchor link can be changed. On the other hand, when it is not possible to change the anchor link, the Frame Body of the wireless frame corresponding to the negation of the anchor link change request includes "NO" and "Reason" as shown in Figure 17(b). "NO" corresponds to a bit that indicates that the anchor link cannot be changed. "Reason" corresponds to a bit that indicates the reason why the anchor link cannot be changed. Note that "Reason" in the wireless frame corresponding to the response to the anchor link change request may be omitted.

[0094] <2-4> How to obtain communication quality Next, a method for obtaining communication quality measurement results in the wireless system 1 according to the first embodiment will be described. There are two possible operations for the base station 10 to obtain communication quality measurement results for each link constituting the multilink: one initiated by the base station 10 and another initiated by the terminal 20. These two operations may be performed periodically or in an event-driven manner. The method for obtaining communication quality measurement results will be described below using the case where the multilink is set to the state shown in Figure 9 as an example.

[0095] (When implemented under the leadership of base station 10) Figures 18 and 19 show an example of how a base station 10 of the wireless system 1 according to this embodiment acquires communication quality measurement results, and correspond to a case where the acquisition of communication quality measurement results is performed periodically under the leadership of the base station 10.

[0096] As shown in Figure 18, the base station 10 uses link #1 (anchor link), link #2, and link #3 to transmit measurement requests to the terminal 20, respectively. The terminal 20 then uses its STA function and quality measurement unit 224 to measure the communication quality of each link based on the receipt of each measurement request, and transmits the measurement results to the base station 10.

[0097] In this example, the base station 10 obtains the communication quality measurement results by sending a communication quality measurement request to the terminal 20 using each link that constitutes the multilink. As a result, the base station 10 can receive the measurement results for link #1, link #2, and link #3 from the terminal 20 via link #1, link #2, and link #3, respectively.

[0098] Furthermore, as shown in Figure 19, the base station 10 may use only the anchor link to send a collective request for communication quality measurement of each link to the terminal 20, or it may receive a collective communication quality measurement result for each link from the terminal 20. In this case, the base station 10 uses the anchor link (link #1) to send the measurement requests for link #1, link #2, and link #3 to the terminal 20. Then, the terminal 20 uses the anchor link to send the communication quality measurement results for link #1, link #2, and link #3 to the base station 10.

[0099] Figure 20 shows an example of how a base station 10 of the wireless system 1 according to this embodiment acquires communication quality, and corresponds to a case where the acquisition of communication quality is performed in an event-driven manner, led by the base station 10. The link management unit LM1 of the base station 10 sequentially performs the operations shown in Figure 20 when multilink is active.

[0100] Specifically, the quality measurement unit 124 of the base station 10 measures the communication quality of each link constituting the multilink (step S40). Then, the link management unit LM1 of the base station 10 checks whether the communication quality of each link meets predetermined conditions (step S41). If the communication quality of each link meets the predetermined conditions (step S41, YES), the link management unit LM1 of the base station 10 terminates its operation. On the other hand, if the communication quality of each link does not meet the predetermined conditions (step S41, NO), the base station 10 requests the terminal 20 to measure the communication quality (step S42).

[0101] Thus, the base station 10 may measure the quality of each channel it uses and send a measurement request to the terminal 20 when the parameters for evaluating communication quality meet predetermined conditions. Various parameters can be used as parameters for evaluating communication quality; for example, channel utilization rate can be used. In this case, the link management unit LM1 of the base station 10 sends a measurement request to the terminal 20 based on, for example, that the channel utilization rate of the anchor link has fallen below a predetermined threshold.

[0102] (When initiated by terminal 20) Figures 21 and 22 show an example of a method for notifying communication quality by a terminal 20 in the wireless system 1 according to this embodiment, and correspond to a case where notification of communication quality is performed periodically at the initiative of the terminal 20.

[0103] As shown in Figure 21, terminal 20 uses link #1 (anchor link), link #2, and link #3 to notify base station 10 of the communication quality measurement results for link #1, link #2, and link #3, respectively. Based on the received communication quality measurement results, base station 10 then determines whether or not to perform an anchor link change process.

[0104] In this example, terminal 20 periodically measures the communication quality on each channel and voluntarily transmits the measurement results to base station 10 using each link that constitutes the multilink. As a result, base station 10 can receive the measurement results for link #1, link #2, and link #3 from terminal 20 via link #1, link #2, and link #3, respectively.

[0105] Alternatively, as shown in Figure 22, terminal 20 may use only the anchor link to transmit the combined communication quality measurement results for each link to base station 10. In this case, terminal 20 uses the anchor link (link #1) to transmit the communication quality measurement results for link #1, link #2, and link #3 to base station 10.

[0106] Figure 23 shows an example of a method for notifying communication quality by a terminal 20 in the wireless system 1 according to this embodiment, and corresponds to a case where notification of communication quality is performed in an event-driven manner initiated by the terminal 20. The link management unit LM2 of the terminal 20 sequentially performs the operations shown in Figure 23 when multilink is active.

[0107] Specifically, the quality measurement unit 224 of the terminal 20 measures the communication quality of each link constituting the multilink (step S50). Then, the link management unit LM2 of the terminal 20 checks whether the communication quality of each link meets predetermined conditions (step S51). If the communication quality of each link meets the predetermined conditions (step S51, YES), the link management unit LM1 of the terminal 20 terminates its operation. On the other hand, if the communication quality of each link does not meet the predetermined conditions (step S51, NO), the terminal 20 notifies the base station 10 of the communication quality measurement results (step S52).

[0108] Thus, the terminal 20 may measure the communication quality of each channel constituting the multilink and notify the base station 10 of the communication quality measurement results when the parameters for evaluating communication quality meet a predetermined threshold. Various parameters can be used as parameters for evaluating communication quality; for example, channel utilization rate can be used. In this case, the link management unit LM2 of the terminal 20 notifies the base station 10 of the communication quality measurement results based, for example, that the channel utilization rate of the anchor link has fallen below a predetermined threshold.

[0109] <3> Effects of the Embodiment The wireless system 1 according to the embodiment described above can improve communication stability during multilink operation. The effects of the wireless system 1 according to the embodiment will be described in detail below.

[0110] Base stations and terminals using wireless LANs may have multiple STA functions, each provided for a specific frequency band, such as 2.4GHz, 5GHz, and 6GHz. In such wireless systems, a wireless connection is established and data communication between the base station and terminal is performed by selecting one of the multiple STA functions. In this case, the wireless system will not use any STA functions that are not selected, even if there is a base station corresponding to the frequency band of that STA function.

[0111] In contrast, the wireless system 1 according to this embodiment establishes a multilink between the base station 10 and the terminal 20 by utilizing multiple STA functions provided by each of the base station 10 and the terminal 20. Multilink data communication can use multiple bandwidths simultaneously and fully utilize the functions provided by the wireless LAN device. As a result, the wireless system 1 according to this embodiment can achieve efficient communication and improve communication speed.

[0112] Furthermore, as a method of operating the multilink, it is conceivable to set up an anchor link used for sending and receiving information related to the control of the multilink. By setting up an anchor link, the wireless system 1 can simplify communication between the link management unit LM1 of the base station 10 and the link management unit LM2 of the terminal 20.

[0113] On the other hand, in a multilink system, the communication stability may differ for each link that makes up the multilink. For example, interference conditions due to OBSS and radio wave intensity can vary depending on the frequency band being used. Therefore, when an anchor link is set up in a multilink system, the communication quality of the anchor link may be lower than that of the other links. Since the anchor link is used to control the entire multilink system, it is preferable that it has higher communication quality than the other links.

[0114] Therefore, the wireless system 1 according to this embodiment changes the anchor link settings according to the communication quality of each link used in the multilink. Specifically, the quality measurement unit 224 of the terminal 20 measures the communication quality of each link constituting the multilink and notifies the base station 10 of the measurement results. Then, the quality measurement unit 124 of the base station 10 periodically evaluates the communication quality of each link constituting the multilink based on the received communication quality measurement results.

[0115] Then, when the quality measurement unit 124 detects, for example, that "channel utilization rate on the anchor link > channel utilization rate on other links", the link management unit LM1 sets the link with a lower channel utilization rate than the anchor link as the anchor link. When the anchor link setting is changed in this way, the channel utilization rate on the anchor link decreases, and the communication quality of the anchor link improves.

[0116] As described above, in the wireless system 1 according to the embodiment, the anchor link is appropriately changed based on predetermined conditions to maintain a high level of communication quality for the anchor link. As a result, the wireless system 1 according to the embodiment can suppress the deterioration of the overall communication quality of the multilink due to the transmission of control information on a link with low communication quality, and can improve the communication stability when using the multilink. Note that the role of the anchor link is not limited to the transmission and reception of information related to the control of the multilink as described above. The anchor link only needs to play a different role from the other links in the multilink. For example, the anchor link may be used to notify traffic information (information on data stored at the access point) on each link. The anchor link may be used to transmit traffic that requires low latency. When the anchor link communicates with a specific communication device, the weighting of traffic between the anchor link and the other links may be changed.

[0117] <4> Modified Examples of Embodiments In this embodiment, the example illustrates a case where the base station 10 establishes a multilink with one terminal 20, but the base station 10 may establish a multilink with multiple terminals 20. Below, as an example of a modification of the embodiment, variations in operation when the base station 10 and multiple terminals 20 establish a multilink will be described.

[0118] Figure 24 shows an example of the overall configuration of a wireless system 1 according to a modified embodiment. As shown in Figure 24, in the modified embodiment, three terminals 20A, 20B, and 20C are connected to the base station 10. Multilinks are established between the base station 10 and each of the terminals 20A, 20B, and 20C. The number of terminals 20 that can be connected to the base station 10 can be set according to the performance of the base station 10. When multiple terminals 20 are connected to the base station 10, the base station 10 may use both multilink and singlelink.

[0119] Figure 25 shows combinations of link sets and anchor link settings for a multilink used in a modified example of the embodiment of the wireless system 1. A “link set” corresponds to a set of multiple links that constitute a multilink. When a multilink is established between a base station 10 and multiple terminals 20, there are four possible combinations of link sets and anchor link settings for the multilink, as shown in Figure 25.

[0120] The first combination handles the case where the multilink set and anchor link settings are common to all terminals 20. The second combination handles the case where the multilink set can differ among multiple terminals 20, and the anchor link settings are common to all terminals 20. The third combination handles the case where the multilink set is common to all terminals 20, and the anchor link settings can differ among multiple terminals 20. The fourth combination handles the case where the multilink set differs among multiple terminals 20, and the anchor link settings can differ among multiple terminals 20.

[0121] In the following, the first to fourth combinations will be referred to as the first to fourth modified examples of the embodiment. Also, in order to simplify the explanation, the following description will be based on the example where two terminals 20A and 20B are connected to the base station 10.

[0122] <4-1> First Variation Figure 26 shows an example of link management information 121 in a wireless system 1 according to a first modified embodiment. As shown in Figure 26, the link sets of terminals 20A and 20B in the first modified embodiment are the same as the link sets shown in Figure 9. That is, the link set of terminal 20A and the link set of terminal 20B share the same combination of frequency bands and channels for the multiple links constituting the multilink, and also share the same frequency band and channel used as the anchor link. Hereinafter, the links related to STA1, STA2, and STA3 of terminal 20A will be referred to as "link #1", "link #2", and "link #3", respectively. The links related to STA1, STA2, and STA3 of terminal 20B will be referred to as "link #4", "link #5", and "link #6", respectively. In this specification, the case in which the same TID is used for each terminal 20 is illustrated, but different TIDs may be used for each terminal 20. In other words, the correspondence between traffic and TID can be arbitrarily set for each terminal 20.

[0123] Figure 27 shows a specific example of anchor link change processing in a wireless system according to the first modified embodiment. Note that Figure 27 omits the illustration of link #3 of terminal 20A and link #6 of terminal 20B. As shown in Figure 27, in the first modified embodiment, base station 10 transmits a beacon signal containing BSS (Basic Service Set) control information using only the anchor links (for example, link #1 of terminal 20A and link #4 of terminal 20B).

[0124] For example, if the conditions for executing the anchor link change process are met for both terminals 20A and 20B, the link management unit LM1 of the base station 10 will sequentially execute the anchor link change process for terminals 20A and 20B. Specifically, first, the link management unit LM1 of the base station 10 will send an anchor link change instruction to terminal 20A and set the anchor link to link #2 based on the acknowledgment from terminal 20A. Next, the link management unit LM1 of the base station 10 will send an anchor link change instruction to terminal 20B and set the anchor link to link #5 based on the acknowledgment from terminal 20B.

[0125] In this example, link #2 of terminal 20A and link #5 of terminal 20B are set to the same frequency band and channel. Thus, the link management unit LM1 of the base station 10 changes the anchor links so that the frequency band and channel of the anchor links are common for each terminal 20 through anchor link change processing. Once the anchor link change processing is completed for all terminals 20 on which multilinks have been established, the base station 10 transmits beacon signals using only the updated anchor links.

[0126] As described above, the wireless system 1 according to the first modified embodiment performs anchor link change processing for multiple terminals 20 based on the communication quality of the anchor link. As a result, the wireless system 1 according to the first modified embodiment can improve the communication stability of the multilink with each terminal 20, similar to the embodiment.

[0127] Furthermore, if multiple terminals 20 are connected to the base station 10, the link management unit LM1 of the base station 10 may evaluate using the average or maximum value of the busy time rate obtained from each terminal 20. In this case, the link management unit LM1 of the base station 10 will execute the anchor link change process based, for example, on whether the average value of the busy time rate obtained from each terminal 20 exceeds a predetermined threshold. The base station 10 may also execute the anchor link change process in parallel for multiple terminals 20 with which it has established a multilink.

[0128] <4-2> Second variation Figure 28 shows an example of link management information 121 in the wireless system 1 according to a second modification of the embodiment. As shown in Figure 28, in the second modification, the link set of terminal 20A and the link set of terminal 20B share the same frequency band and channel used as the anchor link, but the combination of multiple links constituting the multilink is different. Specifically, in the link set of terminal 20A, STA2 is assigned to channel CH2 of 5GHz and STA3 is assigned to channel CH2 of 2.4GHz. On the other hand, in the link set of terminal 20B, STA2 is assigned to channel CH3 of 5GHz and STA3 is assigned to channel CH3 of 2.4GHz. The other configurations of the respective link sets of terminals 20A and 20B are the same as those shown in Figure 9.

[0129] In the wireless system 1 according to the first modified embodiment, for example, the link management unit LM1 of the base station 10 fixes the frequency band and channel of the anchor link used for multilink. This example will be explained with reference to Figure 29 as the first example of multilink processing in the second modified embodiment. Figure 29 shows the first example of multilink processing in the wireless system 1 according to the second modified embodiment, and corresponds to the operation before establishing a multilink between the base station 10 and the terminal 20.

[0130] As shown in Figure 29, terminal 20 receives the anchor link setting from base station 10 (step S60). Then, the link management unit LM2 of terminal 20 checks whether the channel designated as the anchor link is available (step S61). If the channel designated as the anchor link is not available (step S61, NO), the link management unit LM2 of terminal 20 abandons the establishment of a multilink with base station 10. On the other hand, if the channel designated as the anchor link is available (step S61, YES), the link management unit LM2 of terminal 20 requests base station 10 to establish a multilink (step S62). Note that the process in step S62 corresponds to, for example, the process in step S12 in Figure 10.

[0131] Thus, in the first example of multilink processing in the second modified embodiment, whether or not multilink can be used is determined by whether or not the terminal 20 has access to the specified frequency band and channel. As a result, the first example of multilink processing in the second modified embodiment can guarantee a minimum quality of multilink.

[0132] On the other hand, in the second modified embodiment of the wireless system 1, the channel with the highest communication quality among the multiple terminals 20 may be set as the first anchor link. This example will be explained using Figure 30 as a second example of multilink processing in the second modified embodiment. Figure 30 shows a second example of multilink processing in the wireless system according to the second modified embodiment, and corresponds to the operation before a multilink is established between the base station 10 and the multiple terminals 20.

[0133] As shown in Figure 30, the base station 10 acquires the communication quality of multiple terminals 20 (step S70). The link management unit LM1 of the base station 10 then checks whether the channels available for multilink by the multiple terminals 20 have a predetermined communication quality (step S71). If the channels available for multilink by the multiple terminals 20 do not have the predetermined communication quality (step S71, NO), the link management unit LM1 of the base station 10 sets, for example, a preset anchor link as the first anchor link. On the other hand, if the channels available for multilink by the multiple terminals 20 have the predetermined communication quality (step S71, YES), the link management unit LM1 of the base station 10 sets that common channel as the anchor link (step S72).

[0134] Thus, in the second example of multilink processing in the second modified embodiment, the base station 10 sets an optimal anchor link between the multiple terminals 20. As a result, the second example of multilink processing in the second modified embodiment can improve the communication quality of each multilink of the multiple terminals 20 in the BSS.

[0135] In both the first and second examples of multilink processing in the second modified embodiment described above, the settings of links other than the anchor link may differ for each terminal 20. In other words, in the second modified embodiment, the degree of freedom of the frequency band and channel used for multilink is higher than in the embodiment, so an optimal link set can be configured for each terminal 20. As a result, the wireless system 1 according to the second modified embodiment can improve the communication quality of the multilink for each terminal 20.

[0136] <4-3>Third Variation Figure 31 shows an example of link management information 121 in the wireless system 1 according to a third modified embodiment. As shown in Figure 31, in the third modified embodiment, a common link set is used between the link set of terminal 20A and the link set of terminal 20B, but the anchor link settings are different. Specifically, in the link set of terminal 20A, the anchor link is assigned to channel CH1 at 6 GHz. In the link set of terminal 20B, the anchor link is assigned to channel CH2 at 5 GHz. The other configurations of the respective link sets of terminals 20A and 20B are the same as those shown in Figure 9.

[0137] Figure 32 shows an example of a method for outputting a beacon signal at a base station 10 in a wireless system 1 according to a third modified embodiment. As shown in Figure 32, in the wireless system 1 according to the third modified embodiment, the base station 10 transmits a beacon signal using all the STA functions used in the multilink. As a result, each terminal 20 that has established a multilink with the base station 10 can receive the beacon signal even if the anchor link frequency band and channel are different for each terminal 20.

[0138] In the third modified embodiment, the base station 10 only needs to transmit the beacon signal using at least the frequency band and channel set for the anchor link. The beacon signal may be transmitted using a link other than the anchor link, or it may not be transmitted at all. For example, in the example shown in Figure 32, the transmission of the beacon signal by the STA3 of the base station 10 may be omitted. In the third modified embodiment, the base station 10 can reduce power consumption by omitting the transmission of the beacon signal using the STA function that is not used as the anchor link.

[0139] <4-4>Fourth Variation Figure 33 shows an example of link management information 121 in the wireless system 1 according to the fourth modification of the embodiment. As shown in Figure 33, in the fourth modification, different link sets are used between the link set of terminal 20A and the link set of terminal 20B, and the anchor link settings are also different. Specifically, in the link set of terminal 20A, STA1 is assigned to the 6GHz channel CH1, STA2 is assigned to the 5GHz channel CH2, STA3 is assigned to the 2.4GHz channel CH2, and the anchor link is set to STA1. In the link set of terminal 20B, STA1 is assigned to the 6GHz channel CH2, STA2 is assigned to the 5GHz channel CH3, STA3 is assigned to the 2.4GHz channel CH3, and the anchor link is set to STA1. The other configurations of the respective link sets of terminals 20A and 20B are the same as those shown in Figure 9.

[0140] Figure 34 shows an example of anchor link change processing in a wireless system 1 according to a fourth modified embodiment. As shown in Figure 34, the base station 10 measures the channel utilization rate of each channel (step S80). The link management unit LM1 of the base station 10 then checks whether the channel utilization rate of the anchor link is higher than that of the other links (step S81). If the channel utilization rate of the anchor link is lower than that of the other links (step S81, NO), the link management unit LM1 of the base station 10 maintains the anchor link setting. On the other hand, if the channel utilization rate of the anchor link is higher than that of the other links (step S81, YES), the link management unit LM1 of the base station 10 sets the other link as the anchor link (step S82).

[0141] As described above, the anchor link may be changed based on the measurement results of the communication quality of each link by the base station 10. Furthermore, in the wireless system 1 according to the fourth modified embodiment, for example, the anchor link is used as the main communication link, and the other links are used as auxiliary links. In this case, the base station 10 uses, for example, a channel with low channel utilization as the anchor link for normal data exchange. Then, when traffic increases, for example, the base station 10 uses the other links as auxiliary links, and uses the anchor link and auxiliary links in combination. As a result, the wireless system 1 according to the fourth modified embodiment can improve the communication efficiency of the multilink.

[0142] <5> others In the above embodiment, each STA function may notify the corresponding link management unit LM if the link cannot be maintained due to the movement of the terminal 20 or the like. The link management unit LM2 of the terminal 20 may also change the multilink status with the link management unit LM1 of the base station 10 based on the notification from the STA function. Specifically, for example, the link management unit LM2 of the terminal 20 and the link management unit LM1 of the base station 10 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 121 and 221, 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.

[0143] The configuration of the wireless system 1 according to this embodiment is merely an example, and other configurations are possible. For example, the example given is one in which each of the base station 10 and the terminal 20 is equipped with three STA functions (wireless signal processing units), but it is not limited to this. The base station 10 only needs to be equipped with at least two wireless signal processing units. Similarly, the terminal 20 only needs to be equipped with at least two wireless 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 14 and 24 may support wireless communication on multiple frequency bands using multiple communication modules, or it may support wireless communication on multiple frequency bands using a single communication module.

[0144] Furthermore, the functional configuration of the base station 10 and terminal 20 in the wireless system 1 according to this embodiment is merely an example. The functional configuration of the base station 10 and terminal 20 may be named and grouped in any other way, as long as they are capable of performing the operations described in each embodiment.

[0145] Furthermore, in the wireless system 1 according to the embodiment, the CPUs included in the base station 10 and the terminal 20 may be other circuits. For example, an MPU (Micro Processing Unit) or the like may be used instead of a CPU. Also, each of the processes described in each embodiment may be implemented by dedicated hardware. The wireless system 1 according to each embodiment may have a mixture of processes executed by software and processes executed by hardware, or it may have only one or the other.

[0146] The flowcharts used to describe the operation in each embodiment are merely examples. The order of the operations described in the embodiments may be rearranged to the extent possible, and other operations may be added. Furthermore, the wireless frame format described in the above embodiments is merely an example. The wireless system 1 may use other wireless frame formats as long as it is capable of performing the operations described in each embodiment.

[0147] Furthermore, some or all of the above embodiments may also be described as follows, but are not limited to these descriptions.

[0148] [Note 1] A first wireless signal processing unit configured to transmit and receive wireless signals using a first channel, A second wireless signal processing unit configured to transmit and receive wireless signals using a second channel different from the first channel described above, The system includes a link management unit that establishes a multilink with a terminal using the first wireless signal processing unit and the second wireless signal processing unit described above, and sets an anchor link used for sending and receiving control information related to the operation of the multilink, The above Link Management Department is, Using the first wireless signal processing unit configured in the anchor link, a first wireless frame requesting a change in the anchor link is transmitted to the terminal. A base station that, after the first wireless frame described above has been transmitted, changes the anchor link from the first wireless signal processing unit to the second wireless signal processing unit when either the first wireless signal processing unit or the second wireless signal processing unit receives an acknowledgment from the terminal.

[0149] [Note 2] When the link management unit receives the communication quality measurement results of the first wireless signal processing unit and the second wireless signal processing unit from the terminal, If the communication quality of the first wireless signal processing unit set in the anchor link satisfies the first condition, and the communication quality of the second wireless signal processing unit is higher than that of the first wireless signal processing unit, the first wireless frame is transmitted to the terminal. The base station described in Appendix 1.

[0150] [Note 3] The first condition described above is that the channel utilization rate falls below a first threshold, or that the success rate of receiving the beacon signal via the first wireless signal processing unit by the terminal falls below a second threshold. The base station described in Appendix 2.

[0151] [Note 4] The link management unit, using at least one of the first wireless signal processing unit and the second wireless signal processing unit, periodically instructs the terminal to measure and notify the communication quality of the first wireless signal processing unit and the second wireless signal processing unit, respectively. A base station as specified in any one of the items in Appendix 1 to Appendix 3.

[0152] [Note 5] The link management unit, when the communication quality of the first wireless signal processing unit satisfies the second condition, instructs the terminal to measure and notify the communication quality of the first wireless signal processing unit and the second wireless signal processing unit, using at least one of the first and second wireless signal processing units. A base station as specified in any one of the items in Appendix 1 to Appendix 3.

[0153] [Note 6] The second condition described above is that the channel utilization rate of the first wireless signal processing unit falls below the third threshold. The base station described in Appendix 5.

[0154] [Note 7] A first wireless signal processing unit configured to transmit and receive wireless signals using a first channel, A second wireless signal processing unit configured to transmit and receive wireless signals using a second channel different from the first channel described above, The system includes a link management unit that establishes a multilink with a base station using the first wireless signal processing unit and the second wireless signal processing unit described above, and sets an anchor link used for transmitting and receiving control information related to the operation of the multilink, A terminal in which, when the first radio signal processing unit configured on the anchor link receives a first radio frame from the base station requesting a change of anchor link, the link management unit notifies the base station whether or not the anchor link can be changed using either the first radio signal processing unit or the second radio signal processing unit, and if the notification is an affirmative response, changes the anchor link from the first radio signal processing unit to the second radio signal processing unit.

[0155] [Note 8] When the link management unit receives a request from the base station for measurement and notification of the communication quality of the first radio signal processing unit and the second radio signal processing unit, it measures the communication quality of the first radio signal processing unit and the second radio signal processing unit, and transmits the measurement results of the communication quality of the first radio signal processing unit and the second radio signal processing unit to the base station. The terminals listed in Appendix 7.

[0156] [Note 9] The link management unit periodically measures the communication quality of the first wireless signal processing unit and the second wireless signal processing unit, and periodically transmits the measurement results of the communication quality of the first wireless signal processing unit and the second wireless signal processing unit to the base station. The terminals listed in Appendix 7.

[0157] [Note 10] The link management unit measures the communication quality of the first radio signal processing unit and the second radio signal processing unit, and if the communication quality of the first radio signal processing unit satisfies the first condition, it uses at least one of the first radio signal processing unit and the second radio signal processing unit to transmit the measurement results of the communication quality of the first radio signal processing unit and the second radio signal processing unit to the base station. The terminals listed in Appendix 7.

[0158] [Note 11] The first condition described above is that the channel utilization rate of the first wireless signal processing unit falls below a first threshold. The terminal according to claim 10.

[0159] 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]

[0160] 1… Wireless system 10...Base station 20… Terminal 30… Server 11,21…CPU 12,22…ROM 13,23…RAM 14,24… Wireless communication module 15…Wired communication module 25…Display 2 hours… storage LM1, LM2… Link Management Department 100,200…Data Processing Unit 110,210…MAC frame processing unit 120,220… Management Department 121,221… Link management information 122,222… Association Processing Unit 123,223… Authentication Processing Unit 124,224...Quality measurement department 125...Data Categorization Department 126... Send queue 127…CSMA / CA Execution Department 128...Data Conflict Management Department 130, 140, 150, 230, 240, 250… Wireless signal processing unit

Claims

[Claim 1] A first wireless signal processing unit configured to transmit and receive wireless signals using a first channel, A second wireless signal processing unit configured to transmit and receive wireless signals using a second channel different from the first channel, The system includes a link management unit that establishes a multilink with a terminal using the first wireless signal processing unit and the second wireless signal processing unit, and sets an anchor link used for sending and receiving control information related to the operation of the multilink, The aforementioned link management unit is Using the first wireless signal processing unit configured in the anchor link, a first wireless frame requesting a change in the anchor link is transmitted to the terminal. A base station that, after the first wireless frame has been transmitted, changes the anchor link from the first wireless signal processing unit to the second wireless signal processing unit when either the first wireless signal processing unit or the second wireless signal processing unit receives an acknowledgment from the terminal.

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