Base station and terminal

Abstract

To provide a base station and a terminal that improve a communication quality of a multi-link.SOLUTION: A base station 10 in a wireless system 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 multi-link with a terminal 20 by using the first and second wireless signal processing units (links #1 and #2), and sets an anchor link to be used in transmission and reception of control information regarding an operation of the multi-link. The link management unit transmits to the terminal a first wireless frame requesting change of the anchor link by using the first wireless signal processing unit set to the anchor link, and changes the anchor link from the first wireless signal processing unit to the second wireless signal processing unit if either the first wireless signal processing unit or the second wireless signal processing unit receives an acknowledgement from the terminal after the first wireless frame is transmitted.SELECTED DRAWING: Figure 15

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 multi-link 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 multi-link. The link management unit transmits a first radio frame requesting a change of the anchor link to the terminal using the first radio signal processing unit set for the anchor link, and after the first radio frame is transmitted, if either the first radio signal processing unit or the second radio signal processing unit receives an affirmative response from the terminal, the anchor link is changed from the first radio signal processing unit to the second radio signal processing unit.

Advantages of the Invention

[0006] The base station of the embodiment can improve the communication quality of the multi-link.

Brief Description of the Drawings

[0007]

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Embodiments for Carrying Out the Invention

[0008] Hereinafter, a wireless system 1 according to an embodiment will be described with reference to the drawings. The embodiment exemplifies an apparatus and a method for embodying the technical idea of the invention. The drawings are schematic or conceptual. Dimensions, ratios, etc. in each drawing are not necessarily the same as those in reality. The technical idea of the present invention is not specified 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 FIG. 1 shows an example of the configuration of a wireless system 1 according to an embodiment. As shown in FIG. 1, the wireless system 1 includes, for example, a base station 10, a terminal 20, and a server 30.

[0010] The base station 10 is connected to the network NW and is used as an access point for a wireless LAN. For example, the base station 10 can wirelessly distribute data received from the network NW to the terminal 20. In addition, the base station 10 can be connected to the terminal 20 using one type of band or a plurality of types of bands. In this specification, wireless connection using a plurality of types of bands between the base station 10 and the terminal 20 is referred to as "multi-link". Communication between the base station 10 and the terminal 20 is based on, for example, the IEEE802.11 standard.

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

[0012] The server 30 can hold various information, and for example, holds data of content targeted at the terminal 20. The server 30 is, for example, wired-connected to the network NW and configured to be able to communicate with the base station 10 via the network NW. Note that the server 30 only needs to be able to communicate with at least the base station 10. That is, the communication between the base station 10 and the server 30 may be wired or wireless.

[0013] In the wireless system 1 according to the embodiment, the 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, the communication function is 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, an LLC (Logical Link Control) layer and a MAC (Media Access Control) layer. The LLC layer adds, for example, a DSAP (Destination Service Access Point) header, an SSAP (Source Service Access Point) header, etc. to the data input from the upper application to form an LLC packet. The MAC layer adds a MAC header to the LLC packet, for example, to form a MAC frame.

[0015] (Regarding the frequency band used for wireless communication) Figure 2 shows an example of the frequency bands used for wireless communication in the wireless system 1 according to the embodiment. As shown in Figure 2, in wireless communication, for example, the 2.4 GHz band, 5 GHz band, and 6 GHz band are used. And each frequency band includes a plurality of channels respectively. In this example, each of the 2.4 GHz band, 5 GHz band, and 6 GHz band includes at least three channels CH1, CH2, and CH3. Communication using each channel CH is realized by the STA function described later.

[0016] Note that the wireless system 1 may use frequency bands other than the 2.4 GHz band, 5 GHz band, and 6 GHz band for wireless communication. It is only necessary that at least one channel CH is set for each frequency band. For multi-link, channels CH in the same frequency band may be used, or channels CH in different frequency bands may be used.

[0017] (Regarding the format of the wireless frame) Figure 3 shows a specific example of the format of the wireless frame used for communication between the base station 10 and the terminal 20 in the wireless system 1 according to the embodiment. As shown in Figure 3, as the fields included in the wireless frame, for example, there are 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. Some of these fields are included and some are not included depending on the type of the 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 an error detection code for the MAC header and the Frame Body field and is used to determine whether there is an error in the wireless frame.

[0019] The Frame Control field indicates various control information and includes, for example, a Type value, a Subtype value, a To DS (To Distribution System) value, and a From DS value. The Type value indicates the frame type of the wireless frame. For example, the Type value "00" indicates that the wireless frame is a management frame. The Type value "01" indicates that the wireless frame is a control frame. The Type value "10" indicates that the wireless frame is a data frame.

[0020] The content of the wireless frame varies depending on the combination of the Type value and the Subtype value. For example, "00 / 1000 (Type value / Subtype value)" indicates that the wireless frame is a beacon signal. The meanings of the To DS value and the From DS value differ depending on their combination. For example, "00 (To DS / From DS)" indicates data between terminals within the same IBSS (Independent Basic Service Set). "10" indicates that the data frame is directed from the outside to the DS (Distribution System). "01" indicates that the data frame is going out of the DS. "11" is used when configuring a mesh network.

[0021] The Duration field indicates the scheduled period of using the wireless link. The multiple Address fields indicate the BSSID, source address, destination address, address of the sender terminal, address of the receiver terminal, etc. The Sequence Control field indicates the sequence number of the MAC frame and the fragment number for fragmentation. The other control information field includes, for example, traffic type (TID) information. The TID information may be inserted at other positions within the wireless frame. The Frame Body field contains information corresponding to the type of the frame. For example, when corresponding to a data frame, the Frame Body field stores data.

[0022] <1-2>Configuration of Base Station 10 FIG. 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 FIG. 4, the base station 10 includes, for example, a CPU (Central Processing Unit) 11, a ROM (Read Only Memory) 12, a RAM (Random Access Memory) 13, a wireless communication module 14, and a wired communication module 15.

[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 and holds programs, control data, etc. for controlling the base station 10. The RAM 13 is, for example, a volatile semiconductor memory and is used as the working area of the CPU 11. The wireless communication module 14 is a circuit used for transmitting and receiving data by wireless signals and is connected to an antenna. Also, the wireless communication module 14 includes, for example, a plurality of communication modules respectively corresponding to a plurality of frequency bands. The wired communication module 15 is a circuit used for transmitting and receiving data by wired signals and is connected to the network NW.

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

[0025] The data processing unit 100 can execute LLC layer processing and upper layer processing on the input data. For example, the data processing unit 100 outputs the data input from the server 30 via the network NW to the MAC frame processing unit 110. Further, the data processing unit 100 transmits the data input from the MAC frame processing unit 110 to the server 30 via the network NW.

[0026] The MAC frame processing unit 110 executes, for example, a part 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. Further, the MAC frame generation unit 110 restores the 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 the data and the process of restoring the data from the MAC frame are based on, for example, the IEEE802.11 standard.

[0027] The management unit 120 manages the link with the terminal 20 based on the notifications received from the wireless 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 in, for example, the RAM 13 and includes information on the terminal 20 wirelessly connected to the base station 10. Further, the management unit 120 includes an association processing unit 122, an authentication processing unit 123, and a quality measurement unit 124. When the association processing unit 122 receives a connection request from the terminal 20 via any of the wireless signal processing units 130, 140, and 150, it executes a protocol related to association. The authentication processing unit 123 executes a protocol related to authentication following the connection request. The quality measurement unit 124 periodically measures and evaluates the communication quality of each channel. Also, the quality measurement unit 124 periodically requests the terminal 20 to measure and report the communication quality. Hereinafter, the combination of the data processing unit 100, the MAC frame processing unit 110, and the management unit 120 is 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, a 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. Also, 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 (e.g., MAC frame) included in the wireless frame to the MAC frame processing unit 110.

[0029] In this way, each of the radio signal processing units 130, 140, and 150 can execute, for example, a part of the MAC layer processing and the layer 1 processing on the input data or radio signal. For example, the radio signal processing unit 130 handles radio signals in the 2.4 GHz band. The radio signal processing unit 140 handles radio signals in the 5 GHz band. The radio signal processing unit 150 handles radio signals in the 6 GHz band. The radio signal processing units 130, 140, and 150 may or may not share the antennas of the base station 10.

[0030] <1-3>Configuration of Terminal 20 FIG. 6 shows an example of the configuration of the terminal 20 included in the wireless system 1 according to the embodiment. As shown in FIG. 6, the terminal 20 includes, for example, a CPU 21, a ROM 22, a RAM 23, a wireless communication module 24, a display 25, and a 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 and holds programs, control data, etc. for controlling the terminal 20. The RAM 23 is, for example, a volatile semiconductor memory and is used as a working area for the CPU 21. The wireless communication module 24 is a circuit used for transmitting and receiving data by radio signals and is connected to an antenna. Also, the wireless communication module 24 includes, for example, a plurality of communication modules corresponding to a plurality of frequency bands respectively. The display 25 displays, for example, a GUI (Graphical User Interface) corresponding to application software. The display 25 may have a function as an input interface of the terminal 20. The storage 26 is a non-volatile storage device and holds, for example, the system software of the terminal 20. Note that the terminal 20 may not include a display. For example, in an IoT terminal, the display 25 may be omitted.

[0032] FIG. 7 shows an example of the functional configuration of the terminal 20 included in the wireless system 1 according to the embodiment. As shown in FIG. 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, the MAC frame processing unit 210, the management unit 220, and the wireless signal processing units 230, 240, and 250 is realized, for example, by the CPU 21 and the 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 execute the LLC layer processing and the upper layer (layer 3 to layer 7) processing on the input data. For example, the data processing unit 200 outputs the data input from the application execution unit 260 to the MAC frame processing unit 210. Also, the data processing unit 200 outputs the data input from the MAC frame processing unit 210 to the application execution unit 260.

[0034] The MAC frame processing unit 210 executes, for example, a part 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. Also, the MAC frame processing unit 210 restores the 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 the data and the process of restoring the data from the MAC frame are based on, for example, the IEEE802.11 standard.

[0035] The management unit 220 manages the link with the base station 10 based on the notifications received from the wireless 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 in, for example, the RAM 23 and includes information on the base station 10 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. When the association processing unit 222 receives a connection response from the base station 10 via any of the wireless signal processing units 230, 240, and 250, it executes a protocol related to association. The authentication processing unit 223 executes a protocol related to authentication following the connection response. The quality measurement unit 224 periodically measures and evaluates the communication quality of each channel. Also, in response to a request for measurement and notification of the communication quality received from the base station 10, the quality measurement unit 224 measures the communication quality with each STA function and notifies the measurement result to the base station 10. Hereinafter, the combination of the data processing unit 200, the MAC frame processing unit 210, and the management unit 220 is 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, a 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. Also, 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 (e.g., MAC frame) included in the wireless frame to the MAC frame processing unit 210.

[0037] In this way, each of the radio signal processing units 230, 240, and 250 can execute, for example, a part of the MAC layer processing and the first layer processing on the input data or radio signal. For example, the radio signal processing unit 230 handles radio signals in the 2.4 GHz band. The radio signal processing unit 240 handles radio signals in the 5 GHz band. The radio signal processing unit 250 handles radio signals in the 6 GHz band. The radio signal processing units 230, 240, and 250 may or may not share the antennas 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. Also, the application execution unit 260 can operate based on the operation of the input interface.

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

[0040] <1-4>Regarding the link management unit LM1 Figure 8 shows the details of the channel access function in the link management unit LM1 of the base station 10 included in the wireless system 1 according to the embodiment. Note that since 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, for example, the description thereof 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. As data categories, for example, “LL (Low Latency)”, “VO (Voice)”, “VI (Video)”, “BE (Best Effort)”, and “BK (Background)” are set. LL is applied to data that requires low latency. Therefore, it is preferable that the LL data is processed with priority over any of the VO, VI, BE, and BK data.

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

[0043] Each of the CSMA / CA execution units 127A, 127B, 127C, 127D, and 127E waits for transmission for a time specified by preset access parameters while confirming by carrier sense that there is no transmission of a wireless signal by other terminals or the like in CSMA / CA. Then, the CSMA / CA execution units 127A, 127B, 127C, 127D, and 127E each retrieve data from the transmission queues 126A, 126B, 126C, 126D, and 126E, and output the retrieved data to at least any one of the wireless signal processing units 130, 140, and 150 via the data collision management unit 128. Then, a wireless signal including the data is transmitted by the wireless signal processing unit (STA function) that has acquired the right of transmission by CSMA / CA.

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

[0045] Still, access parameters are assigned so that wireless signal transmission is prioritized in the order of, for example, LL, VO, VI, BE, and BK. The access parameters include, for example, CWmin, CWmax, AIFS, and TXOPLimit. CWmin and CWmax respectively indicate the minimum value and the maximum value of a contention window, which is the transmission waiting time for collision avoidance. AIFS (Arbitration Inter Frame Space) indicates a fixed transmission waiting time set for each access category for collision avoidance control with a priority control function. TXOPLimit indicates the upper limit value of TXOP (Transmission Opportunity) corresponding to the channel occupancy time. For example, for transmission queue 126, the shorter the CWmin and CWmax are, the easier it is to obtain the transmission right. The priority of transmission queue 126 becomes higher as the AIFS becomes smaller. The amount of data transmitted with one transmission right increases as the value of TXOPLimit becomes larger.

[0046] The data collision management unit 128 prevents data collisions when multiple CSMA / CA execution units 127 acquire the transmission right with the same STA function. Specifically, the data collision management unit 128 adjusts the transmission timing of data for which the categories are different and the transmission right is acquired with the same STA function, and transmits the data to the STA function starting from the category with the higher priority. For example, there may be a case where an STA function that has acquired the transmission right by CSMA / CA of the LL transmission queue 126A acquires the transmission right at the same time as an STA function that has acquired the transmission right by CSMA / CA of any of the other transmission queues 126B to 126E. In this case, the data collision management unit 128 preferentially transmits the data stored in the transmission queue 126A to the STA function. Similarly, in other combinations of the transmission queues 126, data is transmitted in the order based on the priority set for the category. Thereby, collisions between data assigned for transmission to the same STA function are prevented.

[0047] In the embodiment, a form in which the link management units LM1 and LM2 implement a channel access function is described, but each STA function may implement the channel access function. When the link management units LM1 and LM2 implement the channel access function, each STA function detects the state (idle / busy) of the radio channel in the corresponding link, and the link management units LM1 and LM2 determine whether data can be transmitted (such as which link to use for transmission). On the other hand, when each STA function implements the channel access function, each STA function may independently perform carrier sensing and transmit data. At this time, channel access when a plurality of links are used simultaneously may be executed by sharing access parameters through communication between a plurality of STA functions, or may be executed by sharing access parameters by the link management units LM1 and LM2. The base station 10 and the terminal 20 can use a plurality of links simultaneously by transmitting data based on common access parameters among a plurality of STA functions.

[0048] <1-5>Regarding the link management information 121 FIG. 9 shows an example of the link management information 121 in the wireless system 1 according to the embodiment. Since the link management information 221 of the terminal 20 has information similar to the link management information 121 of the base station 10, the description thereof is omitted. As shown in FIG. 9, the link management information 121 includes information such as, for example, each of the STA function, frequency band, channel ID, link destination ID, multi-link, and TID.

[0049] In this example, "STA1" corresponds to a STA function using a frequency band of 6 GHz, that is, the radio signal processing unit 150 or 250. "STA2" corresponds to a STA function using a frequency band of 5 GHz, that is, the radio signal processing unit 140 or 240. "STA3" corresponds to a STA function using a frequency band of 2.4 GHz, that is, the radio signal processing unit 130 or 230. Hereinafter, STA1, STA2, and STA3 are also 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 set frequency band. The link destination ID corresponds to the identifier of the terminal 20 in the link management information 121 and the identifier of the base station 10 in the link management information 221. In this example, a multi-link using STA1, STA2, and STA3 is established. When a multi-link is established, each of the link management units LM1 and LM2 transmits the data input from the upper layer using at least one link of the STA functions associated with the multi-link.

[0051] The base station 10 sets one of the plurality of STA functions as an 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 transmitting and receiving the assigned data, the anchor link transmits and receives control information related to the operation of the multi-link. Note that the combination of the links constituting the multi-link may be different among the plurality of terminals 20 each establishing a multi-link with the base station 10.

[0052] "TID" in the link management information 121 indicates the association between the STA function and the TID information. Each STA function transmits and receives data corresponding to the assigned TID information. For example, each of TID#1 to 4 corresponds to one of LL, VO, VI, BE, and BK. For one traffic, that is, one TID information, one STA function may be associated, or a plurality of STA functions may be associated. 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] A traffic flow corresponding to the association between such traffic and the STA function is preset when setting up a multi-link between the base station 10 and the terminal 20. For example, the link management unit LM2 of the terminal 20 determines the association between the traffic and the STA function and requests the link management unit LM1 of the base station 10. Then, the base station 10 responds to the request, and the association between the traffic and the STA function is determined.

[0054] In addition, the traffic is set to be evenly distributed among, for example, a plurality of links constituting the multi-link. However, it is not limited to this, and traffic of similar types (priority / non-priority, etc.) to each other may be collected on one link constituting the multi-link. Also, as the association between the STA function and the traffic, for example, voice is associated with the 2.4 GHz frequency band, and video is associated with 5G. In this way, it is preferable that the frequency used for transmission and reception is allocated according to the type of information to be handled and the data capacity.

[0055] <2>Operation of the wireless system 1 Hereinafter, an example of various operations related to the multi-link of the wireless system 1 according to the embodiment will be described. In the following description, for the sake of simplicity, the STA1, STA2, and STA3 of the base station 10 are also referred to as "access point AP". The fact that the STA1, STA2, and STA3 of the terminal 20 transmit wireless signals to the access point AP corresponds to transmitting wireless signals to the STA1, STA2, and STA3 of the base station 10, respectively. When STA1, STA2, and STA3 are described separately, these indicate the STA functions of the terminal 20.

[0056] <2-1>Multi-link processing Figure 10 shows an example of the flow of multi-link processing in the wireless system 1 according to the embodiment. As shown in Figure 10, in multi-link processing, for example, the processes of steps S10 to S16 are executed in order. Hereinafter, the processes of steps S10 to S16 will be described by taking as an example the case where a multi-link is formed using three STA functions.

[0057] In the process of step S10, the terminal 20 transmits a probe request to the base station 10. The probe request is a signal for checking whether the base station 10 exists around the terminal 20. The Frame Control field of the probe request contains, for example, "00 / 0100 (Type value / Subtype value)". When the base station 10 receives the probe request, it executes the process of step S11.

[0058] In the process of step S11, the base station 10 transmits a probe response to the terminal 20. The probe response is a signal used by the base station 10 for responding to the 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 of step S12.

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

[0060] In the process of step S13, the link management unit LM1 of the base station 10 executes a multi-link association process using one STA function. Specifically, first, the base station 10 executes an association process of the first STA function with the terminal 20. Then, when a wireless connection (link) is established in the first STA function, the link management unit LM1 of the base station 10 uses the first STA function in which the link is established to execute an association process of the second STA function and an association process of the third STA function. That is, the STA function in which the link is established is used for the association process of the STA function in which the link is not established. When the association processes of at least two STA functions are completed, the base station 10 establishes a multi-link and executes the process of step S14.

[0061] In the process of step S14, the link management unit LM1 of the base station 10 updates the link management information 121. Note that in this example, the process of step S14 is executed after two links are established, but the link management information 121 may be updated each time the link state is updated, or may be updated when the multi-link is established. When the multi-link is established and the link management information is updated, the base station 10 executes the process of step S15.

[0062] In the process of step S15, the base station 10 transmits a multi-link establishment response to the terminal 20. The multi-link establishment response is a signal used by the base station 10 for a response to a multi-link request from the terminal 20. The Frame Control field of the multi-link association request includes, for example, "00 / 0001 (Type value / Subtype value)". The link management unit LM2 of the terminal 20 recognizes that the multi-link with the base station 10 is established based on receiving the multi-link establishment response. When the terminal 20 receives the multi-link establishment response, it executes the process of step S16.

[0063] In the process of 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 the multi-link with the base station 10 has been established. Thereby, the multi-link process in the wireless system 1 according to the embodiment is completed, and data communication using the multi-link becomes possible between the base station 10 and the terminal 20.

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

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

[0066] FIG. 12 shows a specific example of a beacon signal including multi-link capability information in the wireless system 1 according to the embodiment. As shown in FIG. 12, the beacon signal includes, for example, multi-link capability information, operation information of link #1, operation information of link #2, and operation information of link #3. These information are generated by the link management unit LM1 of the base station 10.

[0067] The multi-link capability information indicates whether the base station 10 is multi-link capable. For example, when the multi-link capability information is "0", it indicates that multi-link is not possible. When the multi-link capability information is "1", it indicates that multi-link is possible. The link operation information (operational parameters) indicates the parameters for data transmission and the like in the links that can be used for multi-link. For example, the operation information of link #1 indicates the access parameters of EDCA (Enhanced Distributed Channel Access) for performing transmission control in the link.

[0068] When the terminal 20 receives the beacon signal described with reference to FIG. 12, it checks the multi-link capability information and the operation information of each link that is the target of multi-link from the beacon signal. Then, when making a multi-link association request, the link management unit LM2 of the terminal 20 notifies the link management unit LM1 of the base station 10 of information such as the links that are the target of multi-link. Thereby, the link management unit LM1 of the base station 10 can execute the association of a plurality of links designated by the link management unit LM2 of the terminal 20 in a batch and establish a multi-link with the terminal 20.

[0069] In addition, when the above-described beacon signal is transmitted only on the anchor link, the beacon signal may not have a field indicating the anchor link. On the other hand, when the beacon signal is transmitted on the anchor link and other links, the beacon signal may have a field indicating the anchor link and a field indicating other links. Also, the base station 10 may add the information included in the above-described beacon signal to the probe response. In this case, the link management unit LM2 of the terminal 20 can transmit a multi-link association request designating the link to be used to the base station 10 without receiving the beacon signal. Further, the base station 10 and the terminal 20 may execute an authentication process when establishing a multi-link.

[0070] <2-2>Data Transfer during Multi-Link FIG. 13 shows an example of a data transmission method during multi-link in the base station 10 included in the wireless system 1 according to the embodiment. As shown in FIG. 13, when the base station 10 acquires data from the upper layer, it sequentially executes the processes of steps S20 to S22. The processes of steps S20 to S22 will be described below.

[0071] In the process of step S20, the link management unit LM1 acquires the 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 added to the data acquired from the upper layer, for example.

[0072] In the process of 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. Note that, in the process of step S21, the number of STA functions acquired by the link management unit LM1 may be one or plural.

[0073] In the process of step S22, the link management unit LM1 outputs the data to the acquired STA function. When one STA function is associated with the output data (traffic), the data is serially transmitted using one STA function. On the other hand, when a plurality of STA functions are associated with the traffic, the data is parallelly transmitted using the plurality of STA functions.

[0074] When one traffic is transmitted in parallel, data distribution and rearrangement 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 link management unit LM on the transmission side, and data rearrangement is performed by the link management unit LM on the reception side. For example, the link management unit LM on the transmission side adds a flag indicating multi-link and an identification number to the radio frame. The link management unit LM on the reception side performs data rearrangement based on the added flag and identification number.

[0075] Also, in the wireless system 1 according to the embodiment, when the link management unit LM receives a plurality of data from the upper layer, it may perform aggregation by combining the received plurality of data. Aggregation in multi-link may be used as an optional function whose execution can be selected by the user.

[0076] <2-3>Regarding the anchor link change process The wireless system 1 according to the embodiment can change the anchor link based on a predetermined condition during multi-link. Hereinafter, the process for the wireless system 1 to change the anchor link is referred to as "anchor link change process".

[0077] (Regarding the execution conditions of the anchor link change process) First, an example of the execution conditions of the anchor link change process will be described. FIG. 14 is a flowchart showing an example of the execution conditions of 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 FIG. 14 during multi-link.

[0078] Specifically, the quality measurement unit 124 of the base station 10 acquires the communication quality measurement results of each link for which multi-link is established 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). Then, the link management unit LM1 of the base station 10 checks whether the communication quality of the anchor link satisfies a predetermined condition (step S32).

[0079] When the communication quality of the anchor link satisfies a predetermined condition (step S32, YES), the link management unit LM1 of the base station 10 ends the process without changing the anchor link. On the other hand, when the communication quality of the anchor link does not satisfy a predetermined condition (step S32, NO), the link management unit LM1 of the base station 10 checks whether the communication quality of other links satisfies a predetermined condition (step S33).

[0080] When the communication quality of other links does not satisfy a predetermined condition (step S33, NO), the link management unit LM1 of the base station 10 ends the process without changing the anchor link. On the other hand, when the communication quality of other links satisfies a predetermined condition (step S33, YES), the link management unit LM1 of the base station 10 executes an anchor link change process (step S34). The link management unit LM1 of the base station 10 changes the anchor link to one of the other links by the anchor link change process and completes the process.

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

[0082] When the channel utilization rate is used as a predetermined condition, the STA function of the terminal 20 measures the busy time ratio of each channel by carrier sense (CCA (Clear Channel Assessment) of the IEEE 802.11 standard). The busy time ratio corresponds to the ratio of the time during which the received power exceeds a certain threshold. The measurement results of the busy time ratio of each channel are transmitted to the quality measurement unit 224 of the terminal 20. Then, the quality measurement unit 124 of the base station 10 requests the terminal 20 to measure and notify the communication quality, and acquires the busy time ratio measured by the quality measurement unit 224 of the terminal 20. Then, when the busy time ratio of the channel of the anchor link exceeds a predetermined threshold, the link management unit LM1 of the base station 10 executes an anchor link change process. In the anchor link change process, for example, the channel with the smallest busy time ratio among the plurality of channels establishing the multi-link is determined as the anchor link.

[0083] When the reception success rate of the beacon signal is used as a predetermined condition, the base station 10 requests the terminal 20 to measure and notify the communication quality, and transmits the beacon signal using a plurality of channels establishing the multi-link during a predetermined period. Then, the quality measurement unit 224 of the terminal 20 measures the number of beacon signals received successfully during the predetermined period for each channel, and reports the measurement results to the base station 10. Then, when the ratio of the number of transmitted beacon signals to the number of beacon signals received successfully by the terminal 20 is below a certain threshold, the link management unit LM1 of the base station 10 executes an anchor link change process. In the anchor link change process, for example, the channel that receives the most beacon signals among the plurality of channels establishing the multi-link is determined as the anchor link. Note that when the beacon signal is transmitted only on the anchor link, signals for communication quality measurement may be transmitted on other channels, or existing signals whose transmission period and number of transmissions are known in advance may be used.

[0084] When the interference situation of OBSS is used as a predetermined condition, the quality measurement unit 124 of the base station 10 checks whether the interference of OBSS in the anchor link is greater than that in other links. In other words, the quality measurement unit 124 checks whether the channel occupancy time of OBSS for the anchor link is greater than that for other links. Note that, for the evaluation of interference, factors other than the channel occupancy time may be used, as long as at least factors that make the channel busy during periods other than the signal exchange of its own BSS are used. For example, for the evaluation of interference, the magnitude of interference power, interference from other communication systems, the presence of noise power, etc. may be used.

[0085] Note that, in the above description, the case where one parameter is used as a predetermined condition is exemplified, but a plurality of parameters may be used as a predetermined condition. 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 reception success rate of beacon signals. For example, when the reception success rate of beacon signals is below a predetermined threshold and the maximum value of the channel occupancy time ratio of OBSS of other links is below a predetermined threshold, the link management unit LM1 of the base station 10 may execute an anchor link change process to change the anchor link to any of the other links.

[0086] (Specific example of anchor link change process) Next, a specific example of the anchor link change process will be described with reference to FIG. 15. FIG. 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 multi-link in this example is set to the state shown in FIG. 9. "Anchor" indicates that it is set in the anchor link. "Normal" indicates a link that is not set in the anchor link. Hereinafter, a link that is not set in the anchor link will be referred to as a "normal link".

[0087] As shown in FIG. 15, when Link #1 is an 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 transmits a communication quality measurement instruction to the terminal 20 in order to periodically check the communication quality of the multi-link. The communication quality measurement instruction is transmitted, for example, using the anchor link (Link #1). Then, based on receiving the communication quality measurement instruction, the quality measurement unit 224 of the terminal 20 measures the communication quality of each link constituting the multi-link and transmits the communication quality measurement result to the access point AP.

[0088] When the access point AP receives the communication quality measurement result, 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 transmits an anchor link change instruction to the terminal 20 using the anchor link (Link #1).

[0089] When the terminal 20 receives the anchor link change instruction, if the link management unit LM2 of the terminal 20 can permit the change of the anchor link, it transmits an affirmative response (“OK”) to the terminal 20 via the anchor link. On the other hand, when the link management unit LM2 of the terminal 20 cannot permit the change of the anchor link, it transmits a negative response (“NG”) to the base station 10 via the anchor link (not shown). When the link management unit LM2 of the terminal 20 transmits an affirmative response to the access point AP, it changes the anchor link of the multi-link to Link #2 and changes Link #1 to a normal link. When the access point AP receives an affirmative response to the anchor link change instruction from the 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 may execute the anchor link change process based on the communication quality of each link constituting the multi-link, and set a link having a higher communication quality than the current anchor link as the next anchor link. Further, 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 is lower than the communication quality of other links, regardless of the state of the communication quality of the anchor link. The "positive response" and "negative response" may be transmitted using a link other than the anchor link.

[0091] (Regarding the radio frame used in the anchor link change process) FIG. 16 and FIG. 17 show specific examples of radio frames used in the anchor link change process of the wireless system 1 according to the embodiment. FIG. 16 corresponds to a radio frame transmitted when the access point AP requests the terminal 20 to change the anchor link. FIG. 17 corresponds to a radio frame returned by the terminal 20 to the access point AP in response to the request for changing the anchor link.

[0092] As shown in FIG. 16, the Frame Body of the radio frame requesting the change of the anchor link includes, for example, a terminal identifier AID (Association Identifier), an anchor link change request, and an identifier of the link to be the target of the change of the anchor link. The link management unit LM2 of the terminal 20 corresponding to the AID refers to the "identifier of the target link" based on the "anchor link change request" and determines whether the change of the anchor link is possible.

[0093] When the anchor link can be changed, the Frame Body of the radio frame corresponding to the positive response to the anchor link change request contains "OK" as shown in Fig. 17(a). "OK" corresponds to the bit notifying that the anchor link can be changed. On the other hand, when the anchor link cannot be changed, the Frame Body of the radio frame corresponding to the negative response to the anchor link change request contains "NO" and "Reason" as shown in Fig. 17(b). "NO" corresponds to the bit notifying that the anchor link cannot be changed. "Reason" corresponds to the bit notifying the reason why the anchor link cannot be changed. Note that "Reason" in the radio frame corresponding to the response to the anchor link change request may be omitted.

[0094] <2-4>Method for Obtaining Communication Quality Next, a method for obtaining the communication quality measurement result in the wireless system 1 according to the first embodiment will be described. As operations for the base station 10 to obtain the communication quality measurement results of each link constituting the multi-link, there are two types: the case where it is executed under the leadership of the base station 10 and the case where it is executed under the leadership of the terminal 20. These two types of operations may be executed periodically or in an event-driven manner. Hereinafter, the method for obtaining the communication quality measurement result will be described by taking the case where the multi-link is set to the state shown in Fig. 9 as an example.

[0095] (When executed under the leadership of the base station 10) Figs. 18 and 19 show an example of the method for obtaining the communication quality measurement result by the base station 10 included in the wireless system 1 according to the embodiment, corresponding to the case where the acquisition of the communication quality measurement result is periodically executed under the leadership of the base station 10.

[0096] As shown in FIG. 18, the base station 10 uses link #1 (anchor link), link #2, and link #3 to transmit a measurement request for link #1, a measurement request for link #2, and a measurement request for link #3 to the terminal 20, respectively. Then, based on receiving each measurement request, the terminal 20 measures the communication quality of each link using each STA function and the quality measurement unit 224, and transmits the measurement result to the base station 10.

[0097] In this way, in this example, the base station 10 obtains the communication quality measurement result by transmitting a measurement request for communication quality to the terminal 20 using each link constituting the multi-link. As a result, the base station 10 can receive the measurement result of link #1, the measurement result of link #2, and the measurement result of link #3 from the terminal 20 via link #1, link #2, and link #3, respectively.

[0098] Note that, as shown in FIG. 19, the base station 10 may transmit the measurement requests for the communication quality of each link to the terminal 20 together using only the anchor link, or may receive the communication quality measurement results of each link from the terminal 20 together. In this case, the base station 10 uses the anchor link (link #1) to transmit the respective measurement requests for link #1, link #2, and link #3 to the terminal 20. Then, the terminal 20 uses the anchor link to transmit the respective communication quality measurement results of link #1, link #2, and link #3 to the base station 10.

[0099] FIG. 20 shows an example of a method for obtaining communication quality by the base station 10 included in the wireless system 1 according to the embodiment, and corresponds to the case where the acquisition of communication quality is executed in a base station 10-led and event-driven manner. The link management unit LM1 of the base station 10 sequentially executes the operations shown in FIG. 20 during multi-link.

[0100] Specifically, the quality measurement unit 124 of the base station 10 measures the communication quality of each link constituting the multi-link (step S40). Then, the link management unit LM1 of the base station 10 checks whether the communication quality of each link satisfies a predetermined condition (step S41). If the communication quality of each link satisfies the predetermined condition (step S41, YES), the link management unit LM1 of the base station 10 ends the operation. On the other hand, if the communication quality of each link does not satisfy the predetermined condition (step S41, NO), the base station 10 requests the terminal 20 to measure the communication quality (step S42).

[0101] In this way, the base station 10 may measure the quality of each channel used by the base station itself and transmit a measurement request to the terminal 20 when the parameter for evaluating the communication quality satisfies a predetermined condition. Various parameters can be used as the parameter for evaluating the communication quality. For example, the channel utilization rate is used. In this case, the link management unit LM1 of the base station 10 transmits a measurement request to the terminal 20 based on, for example, the channel utilization rate of the anchor link falling below a predetermined threshold value.

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

[0103] As shown in FIG. 21, the terminal 20 uses link #1 (anchor link), link #2, and link #3 to notify the base station 10 of the communication quality measurement results of link #1, link #2, and link #3, respectively. Then, the base station 10 determines whether to execute the anchor link change process based on each received communication quality measurement result.

[0104] As described above, in this example, the terminal 20 periodically measures the communication quality of each channel and spontaneously transmits the measurement results to the base station 10 using each link that constitutes the multi-link. As a result, the base station 10 can receive the measurement results of link #1, link #2, and link #3 from the terminal 20 via link #1, link #2, and link #3, respectively.

[0105] Note that, as shown in FIG. 22, the terminal 20 may also summarize and transmit the measurement results of the communication quality of each link to the base station 10 using only the anchor link. In this case, the terminal 20 transmits the respective communication quality measurement results of link #1, link #2, and link #3 to the base station 10 using the anchor link (link #1).

[0106] FIG. 23 shows an example of a method for notifying the communication quality by the terminal 20 included in the wireless system 1 according to the embodiment, and corresponds to the case where the communication quality notification is executed in a proactive and event-driven manner by the terminal 20. The link management unit LM2 of the terminal 20 sequentially executes the operations shown in FIG. 23 during multi-link.

[0107] Specifically, the quality measurement unit 224 of the terminal 20 measures the communication quality of each link that constitutes the multi-link (step S50). Then, the link management unit LM2 of the terminal 20 checks whether the communication quality of each link satisfies a predetermined condition (step S51). If the communication quality of each link satisfies the predetermined condition (step S51, YES), the link management unit LM1 of the terminal 20 ends the operation. On the other hand, if the communication quality of each link does not satisfy the predetermined condition (step S51, NO), the terminal 20 notifies the base station 10 of the communication quality measurement results (step S52).

[0108] In this way, the terminal 20 may measure the communication quality of each channel constituting the multi-link and notify the base station 10 of the communication quality measurement result when the parameter for evaluating the communication quality satisfies a predetermined threshold. As parameters for evaluating the communication quality, various parameters can be used, for example, the channel utilization rate is used. In this case, the link management unit LM2 of the terminal 20 notifies the base station 10 of the communication quality measurement result based on, for example, the channel utilization rate of the anchor link falling below a predetermined threshold.

[0109] <3>Effects of the Embodiment According to the wireless system 1 according to the embodiment described above, the communication stability during multi-link can be improved. Hereinafter, the details of the effects of the wireless system 1 according to the embodiment will be described.

[0110] Base stations and terminals using a wireless LAN may be provided with a plurality of STA functions provided for each band used, for example, 2.4 GHz, 5 GHz, 6 GHz. In such a wireless system, for example, a wireless connection is established by selecting one of the plurality of STA functions, and data communication is performed between the base station and the terminal. At this time, in the wireless system, even if there is a base station corresponding to the band of the unselected STA function, the unselected STA function remains unused.

[0111] On the contrary, the wireless system 1 according to the embodiment establishes a multi-link between the base station 10 and the terminal 20 by utilizing the plurality of STA functions provided in each of the base station 10 and the terminal 20. Data communication by multi-link can use a plurality of bands in combination, and the functions provided in the wireless LAN device can be fully utilized. As a result, the wireless system 1 according to the embodiment can achieve efficient communication and improve the communication speed.

[0112] In addition, as a method of operating multi-links, it is conceivable to set an anchor link that uses information related to the control of the multi-links for transmission and reception. By setting the anchor link, the radio system 1 can simplify the 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 multi-links, the communication stability may be different for each link constituting the multi-links. For example, the interference situation due to OBSS and the radio wave intensity can vary depending on the frequency band being used. Therefore, when an anchor link is set in the multi-links, the communication quality of the anchor link may be lower than that of the other links. Since the anchor link is used for the control of the entire multi-links, it preferably has a higher communication quality than the other links.

[0114] Therefore, the radio system 1 according to the embodiment changes the setting of the anchor link according to the communication quality of each link used in the multi-links. Specifically, the quality measurement unit 224 of the terminal 20 measures the communication quality of each link constituting the multi-links and notifies the measurement result to the base station 10. Then, the quality measurement unit 124 of the base station 10 periodically evaluates the communication quality of each link constituting the multi-links based on the received communication quality measurement result.

[0115] Then, when the quality measurement unit 124 detects, for example, that "the channel utilization rate in the anchor link > the channel utilization rate in the other links", the link management unit LM1 sets, as the anchor link, a link among the other links that has a lower channel utilization rate than the anchor link. When the setting of the anchor link is changed in this way, the channel utilization rate in 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, by appropriately changing the anchor link based on a predetermined condition, the communication quality of the anchor link is maintained in a high state. As a result, the wireless system 1 according to the embodiment can suppress a decrease in the overall communication quality of the multi-link due to transmission of control information through a link with low communication quality, and can improve the communication stability during multi-link. Note that the role of the anchor link is not limited to transmission and reception of information related to control of the multi-link described above. The anchor link may play a role different from other links within the multi-link. For example, the anchor link may be used to notify traffic information (information on data accumulated in the access point) for 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 the traffic volume may be changed between the anchor link and other links.

[0117] <4>Modification Example of Embodiment In the embodiment, the case where the base station 10 establishes a multi-link with one terminal 20 has been illustrated. However, the base station 10 may establish a multi-link with a plurality of terminals 20. Hereinafter, as a modification example of the embodiment, variations in operations when the base station 10 and a plurality of terminals 20 establish a multi-link will be described.

[0118] FIG. 24 shows an example of the overall configuration of the wireless system 1 according to a modification example of the embodiment. As shown in FIG. 24, in the modification example of the embodiment, three terminals 20A, 20B, and 20C are connected to the base station 10. A multi-link is established between the base station 10 and each of the terminals 20A, 20B, and 20C. Note that 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 a plurality of terminals 20 are connected to the base station 10, the base station 10 may use both a multi-link and a single link.

[0119] FIG. 25 shows a combination of a link set of a multi-link and the setting of an anchor link used in the wireless system 1 according to a modified example of the embodiment. The "link set" corresponds to a set of a plurality of links constituting the multi-link. When a multi-link between the base station 10 and a plurality of terminals 20 is established, four types of combinations as shown in FIG. 25 are conceivable as the combination of the link set of the multi-link and the setting of the anchor link.

[0120] The first combination corresponds to the case where the link set of the multi-link and the setting of the anchor link are common to all the terminals 20. The second combination corresponds to the case where the link set of the multi-link is allowed to be different among the plurality of terminals 20 and the setting of the anchor link is common to all the terminals 20. The third combination corresponds to the case where the link set of the multi-link is common to all the terminals 20 and the setting of the anchor link is allowed to be different among the plurality of terminals 20. The fourth combination corresponds to the case where the link set of the multi-link is allowed to be different among the plurality of terminals 20 and the setting of the anchor link is allowed to be different among the plurality of terminals 20 at each terminal 20.

[0121] Hereinafter, the first to fourth combinations are respectively referred to as the first to fourth modified examples of the embodiment. Further, hereinafter, for the sake of simplifying the explanation, the case where two terminals 20A and 20B are connected to the base station 10 will be described as an example.

[0122] <4-1>First Modified Example FIG. 26 shows an example of the link management information 121 in the wireless system 1 according to the first modification of the embodiment. As shown in FIG. 26, the respective link sets of the terminals 20A and 20B in the first modification are the same as the link sets shown in FIG. 9. That is, between the link set of the terminal 20A and the link set of the terminal 20B, the combinations of the frequency bands and channels of the plurality of links constituting the multi-link are common, and the frequency bands and channels used as the anchor link are common. In the following, the links related to STA1, STA2, and STA3 of the terminal 20A are referred to as "link #1", "link #2", and "link #3", respectively. The links related to STA1, STA2, and STA3 of the terminal 20B are referred to as "link #4", "link #5", and "link #6", respectively. In this specification, the case where the same TID is used for each terminal 20 is illustrated, but different TIDs may be used for each terminal 20. That is, the association between the traffic and the TID can be arbitrarily set for each terminal 20.

[0123] FIG. 27 shows a specific example of the anchor link change process in the wireless system according to the first modification of the embodiment. In FIG. 27, the illustration of link #3 of the terminal 20A and link #6 of the terminal 20B is omitted. As shown in FIG. 27, in the first modification, the base station 10 transmits a beacon signal including the control information of the BSS (Basic Service Set) using only the anchor link (for example, link #1 of the terminal 20A and link #4 of the terminal 20B).

[0124] For example, when the execution conditions for the anchor link change process are satisfied for each of the terminals 20A and 20B, the link management unit LM1 of the base station 10 sequentially executes the anchor link change process for each of the terminals 20A and 20B. Specifically, first, the link management unit LM1 of the base station 10 transmits an anchor link change instruction to the terminal 20A, and sets the anchor link to link #2 based on the positive response from the terminal 20A. Next, the link management unit LM1 of the base station 10 transmits an anchor link change instruction to the terminal 20B, and sets the anchor link to link #5 based on the positive response from the terminal 20B.

[0125] In this example, link #2 of the terminal 20A and link #5 of the terminal 20B are set to the same frequency band and channel. In this way, the link management unit LM1 of the base station 10 changes the anchor link so that the frequency band and channel of the anchor link become common for each terminal 20 by performing the anchor link change process for each terminal 20. When the anchor link change process for all the terminals 20 for which the multi-link is established is completed, the base station 10 transmits a beacon signal using only the updated anchor link.

[0126] As described above, the wireless system 1 according to the first modification of the embodiment executes the anchor link change process for a plurality of terminals 20 based on the communication quality of the anchor link. Thereby, the wireless system 1 according to the first modification of the embodiment can improve the communication stability of the multi-link with each terminal 20, similar to the embodiment.

[0127] In addition, when a plurality of terminals 20 are connected to the base station 10, the link management unit LM1 of the base station 10 may evaluate using the average value or the maximum value of the busy time ratio acquired from each terminal 20. In this case, the link management unit LM1 of the base station 10 executes the anchor link change process based on, for example, the average value of the busy time ratio acquired from each terminal 20 exceeding a predetermined threshold value. Also, the base station 10 may execute the anchor link change process for a plurality of terminals 20 for which the multi-link is established in parallel.

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

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

[0130] As shown in FIG. 29, the terminal 20 receives the setting of the anchor link from the base station 10 (step S60). Then, the link management unit LM2 of the 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 the terminal 20 abandons the establishment of the multi-link with the 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 the terminal 20 requests the base station 10 to establish a multi-link (step S62). Note that the process of step S62 corresponds to, for example, the process of step S12 in FIG. 10.

[0131] As described above, in the first example of the multi-link process in the second modification of the embodiment, whether the multi-link can be used is determined based on whether the frequency band and channel designated for the terminal 20 are available. Thereby, the first example of the multi-link process in the second modification of the embodiment can guarantee the minimum quality of the multi-link.

[0132] On the other hand, in the radio system 1 according to the second modification of the embodiment, the channel with the highest communication quality among a plurality of terminals 20 may be set as the first anchor link. This example will be described with reference to FIG. 30 as the second example of the multi-link process in the second modification of the embodiment. FIG. 30 shows the second example of the multi-link process in the radio system according to the second modification of the embodiment, and corresponds to the operation before establishing the multi-link between the base station 10 and a plurality of terminals 20.

[0133] As shown in FIG. 30, the base station 10 acquires the communication quality of a plurality of terminals 20 (step S70). Then, the link management unit LM1 of the base station 10 checks whether a channel that can be used for multi-link in the plurality of terminals 20 has a predetermined communication quality (step S71). If the channels that can be used for multi-link in the plurality of terminals 20 do not have a 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 that can be used for multi-link in the plurality of terminals 20 have a predetermined communication quality (step S71, YES), the link management unit LM1 of the base station 10 sets the common channel as the anchor link (step S72).

[0134] Thus, in the second example of the multi-link process in the second modification of the embodiment, the base station 10 sets an optimal anchor link among the plurality of terminals 20. Thereby, the second example of the multi-link process in the second modification of the embodiment can improve the communication quality of each multi-link of the plurality of terminals 20 within the BSS.

[0135] In both the first example and the second example of the multi-link process in the second modification of the embodiment described above, the settings of the other links excluding the anchor link may be different for each terminal 20. That is, in the second modification of the embodiment, since the degrees of freedom of the frequency band and channels used for multi-link are higher than those in the embodiment, an optimal link set can be configured for each terminal 20. As a result, the radio system 1 according to the second modification of the embodiment can improve the communication quality of the multi-link for each terminal 20.

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

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

[0138] In addition, in the third modification of the embodiment, the base station 10 only needs to transmit a beacon signal using at least the frequency band and channel set for the anchor link. The beacon signal may or may not be transmitted using a link other than the anchor link. For example, in the example shown in FIG. 32, the transmission of the beacon signal by the STA3 of the base station 10 may be omitted. The base station 10 in the third modification of the embodiment can suppress 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 Modification FIG. 33 shows an example of the link management information 121 in the wireless system 1 according to the fourth modification of the embodiment. As shown in FIG. 33, in the fourth modification, different link sets are used between the link set of the terminal 20A and the link set of the terminal 20B, and the anchor link settings are different. Specifically, in the link set of the terminal 20A, STA1 is assigned to the 6 GHz channel CH1, STA2 is assigned to the 5 GHz channel CH2, STA3 is assigned to the 2.4 GHz channel CH2, and the anchor link is set to STA1. In the link set of the terminal 20B, STA1 is assigned to the 6 GHz channel CH2, STA2 is assigned to the 5 GHz channel CH3, STA3 is assigned to the 2.4 GHz channel CH3, and the anchor link is set to STA1. The other configurations of the respective link sets of the terminals 20A and 20B are the same as the link set shown in FIG. 9.

[0140] FIG. 34 shows an example of the anchor link change process in the wireless system 1 according to the fourth modification of the embodiment. As shown in FIG. 34, the base station 10 measures the channel utilization rate of each channel (step S80). Then, the link management unit LM1 of the base station 10 checks whether the channel utilization rate of the anchor link is higher than the channel utilization rate of the other links (step S81). If the channel utilization rate of the anchor link is lower than the channel utilization rate 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 the channel utilization rate 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. In the radio system 1 according to the fourth modification of the embodiment, for example, the anchor link is used as the main link for communication, and other links are used as auxiliary links. In this case, the base station 10 uses, as the anchor link, for example, a channel with a low channel utilization rate for normal data exchange. Then, when the traffic increases, for example, the base station 10 uses other links as auxiliary links and uses the anchor link and the auxiliary links in combination. As a result, the radio system 1 according to the fourth modification of the embodiment can improve the communication efficiency of the multi-link.

[0142] <5>Others In the above embodiment, each STA function may notify the corresponding link management unit LM when the link cannot be maintained due to the movement of the terminal 20 or the like. Further, the link management unit LM2 of the terminal 20 may change the multi-link state 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 in the multi-link. When the multi-link state is changed, the link management units LM1 and LM2 update the link management information 121 and 221, respectively. Further, the link management units LM1 and LM2 may update the association between the traffic and the STA function according to the increase or decrease in the number of links.

[0143] The configuration of the wireless system 1 according to the embodiment is merely an example, and other configurations may be used. For example, although the case where each of the base station 10 and the terminal 20 includes three STA functions (radio signal processing units) has been illustrated, the present invention is not limited thereto. The base station 10 only needs to include at least two radio signal processing units. Similarly, the terminal 20 only needs to include at least two radio signal processing units. Also, 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 in a plurality of frequency bands by a plurality of communication modules, or may support wireless communication in a plurality of frequency bands by one communication module.

[0144] Also, the functional configurations of the base station 10 and the terminal 20 in the wireless system 1 according to the embodiment are merely examples. The functional configurations of the base station 10 and the terminal 20 may have other names and groupings as long as they can execute the operations described in each embodiment.

[0145] Also, in the wireless system 1 according to the embodiment, the CPU included in each of the base station 10 and the terminal 20 may be other circuits. For example, instead of the CPU, an MPU (Micro Processing Unit) or the like may be used. Also, each of the processes described in each embodiment may be realized 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 may have only one of them.

[0146] In each embodiment, the flowcharts used to explain the operations are merely examples. Each of the operations described in the embodiment may be rearranged within the possible order of processing, or other processes may be added. Also, the format of the wireless frame described in the above embodiment is merely an example. The wireless system 1 may use other wireless frame formats as long as it can execute the operations described in each embodiment.

[0147] Note that some or all of the above embodiments may be described as follows in the appended claims, but are not limited thereto.

[0148] [Appendix 1] A first radio signal processing unit configured to be able to transmit and receive a radio signal using a first channel; A second radio signal processing unit configured to be able to transmit and receive a radio signal using a second channel different from the first channel; A link management unit that establishes a multi-link 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 multi-link. The link management unit Transmits a first radio frame requesting a change of the anchor link to the terminal using the first radio signal processing unit set for the anchor link; After the first radio frame is transmitted, when either the first radio signal processing unit or the second radio signal processing unit receives an affirmative response from the terminal, the base station changes the anchor link from the first radio signal processing unit to the second radio signal processing unit.

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

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

[0151] [Supplementary Note 4] The link management unit uses at least one of the first radio signal processing unit and the second radio signal processing unit to periodically instruct the terminal to measure and notify the communication quality of each of the first radio signal processing unit and the second radio signal processing unit. The base station according to any one of Supplementary Notes 1 to 3.

[0152] [Supplementary Note 5] When the communication quality of the first radio signal processing unit satisfies a second condition, the link management unit uses at least one of the first radio signal processing unit and the second radio signal processing unit to instruct the terminal to measure and notify the communication quality of each of the first radio signal processing unit and the second radio signal processing unit. The base station according to any one of Supplementary Notes 1 to 3.

[0153] [Supplementary Note 6] The second condition is that the channel utilization rate of the first radio signal processing unit is lower than a third threshold. The base station described in Supplementary Note 5.

[0154] [Supplementary Note 7] A first radio signal processing unit configured to be able to transmit and receive radio signals using a first channel, A second radio signal processing unit configured to be able to transmit and receive radio signals using a second channel different from the first channel, A link management unit that establishes a multi-link with a base station using the first radio signal processing unit and the second radio signal processing unit, and sets an anchor link used for transmitting and receiving control information related to the operation of the multi-link. When the first radio signal processing unit set in the anchor link receives a first radio frame requesting a change of the anchor link from the base station, the link management unit notifies the base station of the feasibility of changing the anchor link using either the first radio signal processing unit or the second radio signal processing unit, and when the notification is an affirmative response, changes the anchor link from the first radio signal processing unit to the second radio signal processing unit, a terminal.

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

[0156] [Appendix 9] The link management unit periodically measures the communication quality of each of the first radio signal processing unit and the second radio signal processing unit, and periodically transmits the measurement results of the communication quality of each of the first radio signal processing unit and the second radio signal processing unit to the base station. The terminal according to Appendix 7.

[0157] [Appendix 10] The link management unit measures the communication quality of each of the first radio signal processing unit and the second radio signal processing unit, and when the communication quality of the first radio signal processing unit satisfies a first condition, 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 each of the first radio signal processing unit and the second radio signal processing unit to the base station. The terminal according to Appendix 7.

[0158] [Appendix 11] The first condition is that the channel utilization rate of the first radio signal processing unit is lower than a first threshold value. The terminal according to claim 10.

[0159] Note that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist thereof at the implementation stage. Also, the respective embodiments may be implemented in appropriate combination, and in that case, the combined effects can be obtained. Further, the above-described embodiments include various inventions, and various inventions can be extracted by combinations selected from a plurality of disclosed constituent elements. For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiments, and the problem can be solved and the effects can be obtained, the configuration from which these constituent elements are deleted can be extracted as an invention.

Explanation of Reference Numerals

[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 26... Storage LM1, LM2... Link management unit 100, 200... Data processing unit 110, 210... MAC frame processing unit 120, 220... Management unit 121, 221... Link management information 122, 222... Association processing unit 123, 223... Authentication processing unit 124, 224... Quality measurement unit 125... Data categorization unit 126... Transmission queue 127... CSMA / CA execution unit 128... Data collision management unit 130, 140, 150, 230, 240, 250... Wireless signal processing unit

Claims

【Claim 1】 A first radio signal processing unit configured to be able to transmit and receive radio signals using a first channel; A second radio signal processing unit configured to be able to transmit and receive radio signals using a second channel different from the first channel; A link management unit that establishes a multi-link 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 regarding the operation of the multi-link; and The link management unit is configured to: Transmit a first radio frame requesting a change of the anchor link to the terminal using the first radio signal processing unit set for the anchor link; After the first radio frame is transmitted, when either the first radio signal processing unit or the second radio signal processing unit receives an affirmative response from the terminal, change the anchor link from the first radio signal processing unit to the second radio signal processing unit. A base station.

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