Base station and terminal

Abstract

To provide a base station and a terminal for suppressing power consumption during multi-link.SOLUTION: In a radio system, a base station 10 includes first and second radio signal processing units and a link management unit. The first and second radio signal processing units transmit and receive radio signals by using first and second channels, respectively. The link management unit establishes a multi-link with a terminal using the first and second radio signal processing units, sets the first radio signal processing unit to a primary link used as a main link in the multi-link, sets the second radio signal processing unit to a secondary link as an auxiliary link in the multi-link, and sets the secondary link to an operation stop mode when a first condition is satisfied in a case where the secondary link is in an active mode. If a second condition is satisfied when the secondary link is in the dormant mode, the link management unit sets the secondary link to the active mode.SELECTED DRAWING: Figure 15

Description

[Technical Field]

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

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

[0003] [Non-Patent Document 1] IEEE Std 802.11-2016, “Figure 4-25 Establishing the IEEE 802.11 association” and “11.3 STA authentication and association”, 7 December 2016 Summary of the Invention [Problem to be solved by the invention]

[0004] The challenge is to reduce the power consumption of wireless terminals. [Means for solving the problem]

[0005] A base station according to an embodiment includes a first radio signal processing unit, a second radio signal processing unit, and a link management unit. The first radio signal processing unit is configured to be able to transmit and receive radio signals using a first channel. The second radio signal processing unit is configured to be able to transmit and receive radio signals using a second channel different from the first channel. The link management unit establishes a multilink with a terminal using the first radio signal processing unit and the second radio signal processing unit, sets the first radio signal processing unit to a primary link used as a main link in the multilink, and sets the second radio signal processing unit to a secondary link used as an auxiliary link in the multilink. When the secondary link is in an active mode and a first condition is satisfied in the multilink, the link management unit sets the secondary link to a dormant mode that consumes less power than the active mode. When the secondary link is in the dormant mode and a second condition is satisfied in the multilink, the link management unit sets the secondary link to the active mode. [Effects of the Invention]

[0006] The base station according to the embodiment can reduce power consumption during multi-link. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a conceptual diagram showing an example of the overall configuration of a wireless system according to an embodiment. [Figure 2] FIG. 2 is a conceptual diagram showing a specific example of a format of a radio frame in the radio system according to the embodiment. [Figure 3] FIG. 3 is a block diagram showing an example of the configuration of a base station included in the wireless system according to the embodiment. [Figure 4] FIG. 4 is a block diagram showing an example of functions of a base station included in the wireless system according to the embodiment. [Figure 5] FIG. 5 is a block diagram showing an example of the configuration of a terminal included in the wireless system according to the embodiment. [Figure 6]FIG. 6 is a block diagram showing an example of functions of a terminal included in the wireless system according to the embodiment. [Figure 7] FIG. 7 is a block diagram showing an example of detailed functions of a link management unit of a base station included in the wireless system according to the embodiment. [Figure 8] FIG. 8 is a flowchart showing an example of multi-link processing in the wireless system according to the embodiment. [Figure 9] FIG. 9 is a table showing an example of link management information in the wireless system according to the embodiment. [Figure 10] FIG. 10 is a flowchart showing an example of a data transmission method in a multi-link state in the wireless system according to the embodiment. [Figure 11] FIG. 11 is a flowchart showing a specific example of a method for using multilink power saving in the wireless system according to the embodiment. [Figure 12] FIG. 12 is a table showing an example of changes in link management information due to the use of the multi-link power save described in FIG. [Figure 13] FIG. 13 is a flowchart showing an example of an execution condition for a link activation process in the wireless system according to the embodiment. [Figure 14] FIG. 14 is a flowchart showing an example of an execution condition for the link stop processing in the wireless system according to the embodiment. [Figure 15] FIG. 15 is a flowchart showing a specific example of link start / stop processing in the wireless system according to the embodiment. [Figure 16] FIG. 16 is a conceptual diagram showing a specific example of a radio frame used in the link start / stop process of the wireless system according to the embodiment. [Figure 17] FIG. 17 is a conceptual diagram showing a specific example of a radio frame used in the link start / stop process of the wireless system according to the embodiment. [Figure 18] FIG. 18 is a flowchart illustrating an example of an execution condition for a link activation process in a wireless system according to a first modification of the embodiment. [Figure 19] FIG. 19 is a flowchart illustrating an example of an execution condition for a link stop process in a wireless system according to a first modification of the embodiment. [Figure 20] FIG. 20 is a flowchart illustrating an example of an execution condition for a link activation process in a wireless system according to a second modification of the embodiment. [Figure 21] FIG. 21 is a flowchart illustrating an example of an execution condition for a link stop process in a wireless system according to a second modification of the embodiment. [Figure 22] FIG. 22 is a flowchart illustrating an example of an execution condition for a link activation process in a wireless system according to a third modification of the embodiment. [Figure 23] FIG. 23 is a flowchart illustrating an example of an execution condition for a link stop process in a wireless system according to a third modification of the embodiment. [Figure 24] FIG. 24 is a flowchart showing a specific example of link start / stop processing in a wireless system according to a fourth modification of the embodiment. [Figure 25] FIG. 25 is a conceptual diagram showing a specific example of a radio frame used in a link start / stop process in a wireless system according to a fourth modification of the embodiment. [Figure 26] FIG. 26 is a conceptual diagram illustrating an example of frequency bands used for wireless communication in a wireless system according to a fifth modification of the embodiment. [Figure 27] FIG. 27 is a table illustrating an example of link management information in a wireless system according to a fifth modification of the embodiment. [Figure 28] FIG. 28 is a table illustrating an example of data allocation in multilinks in a wireless system according to a third modification of the embodiment. [Figure 29] FIG. 29 is a flowchart showing an example of an execution condition for a link stop process in a wireless system according to a combination of the embodiment and the first modification of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] The following describes embodiments with reference to the drawings. The embodiments illustrate devices and methods for embodying the technical ideas of the invention. The drawings are schematic or conceptual. The dimensions and proportions of the drawings are not necessarily the same as those in reality. The technical ideas of the present invention are not specified by the shape, structure, arrangement, etc. of the components. In the following description, the same reference numerals are used to designate components having substantially the same functions and configurations.

[0009] <1> Wireless System 1 Configuration The wireless system 1 according to the embodiment relates to a method for starting / stopping links in a multi-link environment.

[0010] <1-1> Overall configuration of wireless system 1 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 a base station 10, a terminal 20, and a server 30, for example.

[0011] The base station 10 is connected to a network NW and is used as an access point of a wireless LAN. For example, the base station 10 can wirelessly distribute data received from the network NW to the terminal 20. The base station 10 can also be connected to the terminal 20 using one type of band or multiple types of bands. In this specification, a wireless connection using multiple types of bands between the base station 10 and the terminal 20 is referred to as a "multi-link." The communication between the base station 10 and the terminal 20 is based on, for example, the IEEE 802.11 standard.

[0012] 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 a server 30 on the network NW via a base station 10 wirelessly connected to the terminal 20. The terminal 20 may also be other electronic devices such as a desktop computer or a laptop computer. The terminal 20 may be any device that can at least communicate with the base station 10 and perform the operations described below.

[0013] The server 30 can store various information, for example, data of content intended for the terminal 20. The server 30 is connected to the network NW by wire, for example, and is configured to be able to communicate with the base station 10 via the network NW. It is sufficient for the server 30 to be able to communicate with at least the base station 10. In other words, communication between the base station 10 and the server 30 may be wired or wireless.

[0014] In the wireless system 1 according to the embodiment, data communication between the base station 10 and the terminal 20 is based on the OSI (Open Systems Interconnection) reference model. In the OSI reference model, communication functions are divided into seven layers (layer 1: physical layer, layer 2: data link layer, layer 3: network layer, layer 4: transport layer, layer 5: session layer, layer 6: presentation layer, and layer 7: application layer).

[0015] The data link layer includes, for example, an LLC (Logical Link Control) layer and a MAC (Media Access Control) layer. The LLC layer adds a DSAP (Destination Service Access Point) header and an SSAP (Source Service Access Point) header to data input from an upper application, for example, to form an LLC packet. The MAC layer adds a MAC header to an LLC packet, for example, to form a MAC frame.

[0016] Fig. 2 shows a specific example of the format of a wireless frame used in communication between the base station 10 and the terminal 20 in the wireless system 1 according to the embodiment. As shown in Fig. 2, the wireless frame includes, for example, a Frame Control field, a Duration field, an Address1 field, an Address2 field, an Address3 field, a Sequence Control field, other control information fields, a Frame Body field, and an FCS (Frame Check Sequence) field.

[0017] The Frame Control field through 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 Frame Body field, and is used to determine whether or not there is an error in the wireless frame.

[0018] The Frame Control field indicates various control information, including, 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, a Type value of "00" indicates that the wireless frame is a management frame. A Type value of "01" indicates that the wireless frame is a control frame. A Type value of "10" indicates that the wireless frame is a data frame.

[0019] The contents of the wireless frame change depending on the combination of the Type and Subtype values. For example, "00 / 1000 (Type value / Subtype value)" indicates that the wireless frame is a beacon signal. The meaning of the To DS and From DS values ​​varies depending on the combination. For example, "00 (To DS / From DS)" indicates that the data is between terminals within the same IBSS (Independent Basic Service Set). "10" indicates that the data frame is directed from outside to the DS (Distribution System). "01" indicates that the data frame is directed outside the DS. "11" is used when configuring a mesh network.

[0020] The Duration field indicates the planned period for using the wireless link. Multiple Address fields indicate the BSSID, source address, destination address, sender terminal address, receiver terminal address, etc. The Sequence Control field indicates the MAC frame sequence number and the fragment number for the fragment. Other control information fields include, for example, traffic type (TID) information. TID information may be inserted at other positions within the wireless frame. The Frame Body field contains information according to the type of frame. For example, the Frame Body field stores data if it corresponds to a data frame.

[0021] <1-2> Configuration of base station 10 3 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. 3, 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.

[0022] 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 stores programs and control data for controlling the base station 10. The RAM 13 is, for example, a volatile semiconductor memory and is used as a work area for the CPU 11. The wireless communication module 14 is a circuit used to transmit and receive data via wireless signals and is connected to an antenna. The wireless communication module 14 also includes, for example, multiple communication modules each corresponding to a multiple frequency band. The wired communication module 15 is a circuit used to transmit and receive data via wired signals and is connected to the network NW.

[0023] Fig. 4 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. 4, the base station 10 includes, for example, a data processing unit 110, a link management unit 120, and radio signal processing units 130, 140, and 150. The processing of the data processing unit 110, the link management unit 120, and the radio signal processing units 130, 140, and 150 is realized by, for example, a CPU 11 and a wireless communication module 14.

[0024] The data processing unit 110 can perform LLC layer processing and upper layer (layers 3 to 7) processing on input data. For example, the data processing unit 110 outputs data input from the server 30 via the network NW to the link management unit 120. The data processing unit 110 also transmits data input from the link management unit 120 to the server 30 via the network NW.

[0025] The link management unit 120 performs, for example, part of MAC layer processing on the input data. The link management unit 120 also manages links with the terminal 20 based on notifications from the radio signal processing units 130, 140, and 150. The link 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 that is wirelessly connected to the base station 10. The link management unit 120 also includes an association processing unit 122 and an authentication processing unit 123. When the association processing unit 122 receives a connection request from the terminal 20 via any of the radio signal processing units 130, 140, and 150, the association processing unit 122 executes a protocol related to association. Following the connection request, the authentication processing unit 123 executes a protocol related to authentication.

[0026] Each of the radio signal processing units 130, 140, and 150 transmits and receives data between the base station 10 and the terminal 20 using radio communication. For example, each of the radio signal processing units 130, 140, and 150 adds a preamble, a PHY header, and the like to data input from the link management unit 120 to create a radio frame. Then, each of the radio signal processing units 130, 140, and 150 converts the radio frame into a radio signal and distributes the radio signal via the antenna of the base station 10. Also, each of the radio signal processing units 130, 140, and 150 converts a radio signal received via the antenna of the base station 10 into a radio frame. Then, each of the radio signal processing units 130, 140, and 150 outputs the data included in the radio frame to the link management unit 120.

[0027] In this way, each of the radio signal processing units 130, 140, and 150 can perform, for example, part of the MAC layer processing and layer 1 processing on input data or radio signals. 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 an antenna of the base station 10.

[0028] <1-3> Configuration of terminal 20 5 shows an example of the configuration of the terminal 20 included in the wireless system 1 according to the embodiment. As shown in FIG. 5, 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.

[0029] 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 stores programs and control data for controlling the terminal 20. The RAM 23 is, for example, a volatile semiconductor memory and is used as a work area for the CPU 21. The wireless communication module 24 is a circuit used to transmit and receive data via wireless signals and is connected to an antenna. The wireless communication module 24 also includes, for example, multiple communication modules corresponding to multiple frequency bands. The display 25 displays, for example, a GUI (Graphical User Interface) corresponding to application software. The display 25 may also function as an input interface for the terminal 20. The storage 26 is a non-volatile storage device and stores, for example, system software for the terminal 20. The terminal 20 does not necessarily have a display. For example, the display 25 may be omitted in an IoT terminal.

[0030] Fig. 6 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. 6, the terminal 20 includes, for example, a data processing unit 210, a link management unit 220, wireless signal processing units 230, 240, and 250, and an application execution unit 260. The processing of the data processing unit 210, the link management unit 220, and the wireless signal processing units 230, 240, and 250 is realized by, for example, the CPU 21 and the wireless communication module 24.

[0031] Data processing unit 210 can perform LLC layer processing and upper layer (layers 3 to 7) processing on input data. For example, data processing unit 210 outputs data input from application execution unit 260 to link management unit 220. Data processing unit 210 also outputs data input from link management unit 220 to application execution unit 260.

[0032] The link management unit 220 performs, for example, part of MAC layer processing on the input data. The link management unit 220 also manages links with the base station 10 based on notifications from the radio signal processing units 230, 240, and 250. The link 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 link management unit 220 also includes an association processing unit 222 and an authentication processing unit 223. When the association processing unit 222 receives a connection request from the base station 10 via any of the radio signal processing units 230, 240, and 250, the association processing unit 222 executes a protocol related to association. Following the connection request, the authentication processing unit 223 executes a protocol related to authentication.

[0033] Each of the radio signal processing units 230, 240, and 250 transmits and receives data between the base station 10 and the terminal 20 using radio communication. For example, each of the radio signal processing units 230, 240, and 250 adds a preamble, a PHY header, and the like to data input from the link management unit 220 to create a radio frame. Then, each of the radio signal processing units 230, 240, and 250 converts the radio frame into a radio signal and distributes the radio signal via the antenna of the terminal 20. Also, each of the radio signal processing units 230, 240, and 250 converts a radio signal received via the antenna of the terminal 20 into a radio frame. Then, each of the radio signal processing units 230, 240, and 250 outputs the data included in the radio frame to the link management unit 220.

[0034] In this way, each of the radio signal processing units 230, 240, and 250 can perform, for example, part of the MAC layer processing and layer 1 processing on input data or radio signals. 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 an antenna of the terminal 20.

[0035] The application execution unit 260 executes an application that can use data input from the data processing unit 210. For example, the application execution unit 260 can display information about the application on the display 25. The application execution unit 260 can also operate based on operations on an input interface.

[0036] In the wireless system 1 according to the embodiment described above, the wireless signal processing units 130, 140, and 150 of the base station 10 are configured to be connectable to the wireless signal processing units 230, 240, and 250 of the terminal 20, respectively. That is, the wireless signal processing units 130 and 230 can be wirelessly connected to each other using the 2.4 GHz band. The wireless signal processing units 140 and 240 can be wirelessly connected to each other using the 5 GHz band. The wireless signal processing units 150 and 250 can be wirelessly connected to each other using the 6 GHz band. In this specification, each wireless signal processing unit may be referred to as an "STA function." That is, the wireless system 1 according to the embodiment has multiple STA functions.

[0037] <1-4> About the Link Management Department 7 shows details of a channel access function in the link management unit 120 of the base station 10 included in the wireless system 1 according to the embodiment. Note that the function of the link management unit 220 of the terminal 20 is similar to that of, for example, the link management unit 120 of the base station 10, and therefore a description thereof will be omitted. As shown in FIG. 7, the link management unit 120 includes, for example, a data categorization unit 124, transmission queues 125A, 125B, 125C, 125D, and 125E, CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance) execution units 126A, 126B, 126C, 126D, and 126E, and a data collision management unit 127.

[0038] The data categorization unit 124 categorizes the data input from the data processing unit 110. Data categories are set, for example, as "LL (Low Latency)", "VO (Voice)", "VI (Video)", "BE (Best Effort)", and "BK (Background)". LL is applied to data that requires low latency. For this reason, it is preferable that LL data be processed with priority over any of VO, VI, BE, and BK data.

[0039] Then, the data categorization unit 124 inputs the categorized data to one of the transmission queues 125A, 125B, 125C, 125D, and 125E. Specifically, LL data is input to the transmission queue 125A. VO data is input to the transmission queue 125B. VI data is input to the transmission queue 125C. BE data is input to the transmission queue 125D. BK data is input to the transmission queue 125E. Then, the input data of each category is accumulated in one of the corresponding transmission queues 125A to E.

[0040] In CSMA / CA, each of CSMA / CA execution units 126A, 126B, 126C, 126D, and 126E confirms by carrier sense that no wireless signals are being transmitted by other terminals, etc., and waits for transmission for a time period specified by a preset access parameter. Then, CSMA / CA execution units 126A, 126B, 126C, 126D, and 126E extract data from transmission queues 125A, 125B, 125C, 125D, and 125E, respectively, and outputs the extracted data to at least one of wireless signal processing units 130, 140, and 150 via data collision management unit 127. Then, a wireless signal containing the data is transmitted by the wireless signal processing unit (STA function) that has acquired the transmission right through CSMA / CA.

[0041] The CSMA / CA execution unit 126A performs CSMA / CA on the LL data held in the transmission queue 125A. The CSMA / CA execution unit 126B performs CSMA / CA on the VO data held in the transmission queue 125B. The CSMA / CA execution unit 126C performs CSMA / CA on the VI data held in the transmission queue 125C. The CSMA / CA execution unit 126D performs CSMA / CA on the BE data held in the transmission queue 125D. The CSMA / CA execution unit 126E performs CSMA / CA on the BK data held in the transmission queue 125E.

[0042] The access parameters are assigned so that wireless signal transmission is prioritized in the following order: LL, VO, VI, BE, and BK. The access parameters include, for example, CWmin, CWmax, AIFS, and TXOPLimit. CWmin and CWmax indicate the minimum and maximum values, respectively, of the contention window (CW), which is the transmission waiting time for collision avoidance. AIFS (Arbitration Inter Frame Space) indicates a fixed transmission waiting time set for each access category for collision avoidance control with a priority control function. TXOPLimit indicates the upper limit of TXOP (Transmission Opportunity), which corresponds to the channel occupancy time. For example, the shorter the CWmin and CWmax, the easier it is for the transmission queue 125 to obtain the transmission right. The smaller the AIFS, the higher the priority of the transmission queue 125. The larger the value of TXOPLimit, the greater the amount of data transmitted with one transmission right.

[0043] The data collision management unit 127 prevents data collisions when multiple CSMA / CA execution units 126 acquire the transmission right using the same STA function. Specifically, the data collision management unit 127 adjusts the transmission timing of data in different categories that have been acquired by the same STA function, and transmits data from the highest priority category to the STA function. For example, the STA function that has acquired the transmission right using CSMA / CA in the LL transmission queue 125A may be the same as the STA function that has acquired the transmission right using CSMA / CA in one of the other transmission queues 125B to 125E. In this case, the data collision management unit 127 prioritizes transmitting the data stored in the transmission queue 125A to the STA function. Similarly, for other combinations of transmission queues 125, data is transmitted in the order based on the priority set for the category. This prevents collisions between data assigned for transmission to the same STA function.

[0044] In this embodiment, the link management unit implements the channel access function. However, each STA function may also implement the channel access function. When the link management unit implements the channel access function, each STA function detects the state (idle / busy) of the wireless channel of the corresponding link, and the link management unit determines whether data can be transmitted (e.g., which link to use for transmission). On the other hand, when each STA function implements the channel access function, each STA function independently performs carrier sensing and transmits data. In this case, channel access when multiple links are used simultaneously may be performed by sharing access parameters between the multiple STA functions, or by sharing access parameters through the link management unit. The base station 10 and the terminal 20 can simultaneously use multiple links by transmitting data based on access parameters common to the multiple STA functions.

[0045] <2> Operation of Radio System 1 An example of various operations related to multilink in the wireless system 1 according to the embodiment will be described below. In the following description, for simplicity, STA1 and STA2 of the base station 10 will also be referred to as "access point AP." Transmission of wireless signals from STA1 and STA2 of the terminal 20 to the access point AP corresponds to transmission of wireless signals to STA1 and STA2 of the base station 10, respectively. When STA1 and STA2 are described individually, they indicate the STA function of the terminal 20.

[0046] <2-1> Multi-link processing 8 is a flowchart showing an example of multi-link processing in the wireless system 1 according to the embodiment. As shown in FIG. 8, in the multi-link processing, for example, steps S10 to S16 are executed in order.

[0047] Specifically, first, in the process of step S10, the terminal 20 transmits a probe request to the base station 10. The probe request is a signal that confirms whether or not a base station 10 is present in the vicinity of the terminal 20. The Frame Control field of the probe request contains, for example, "00 / 0100 (Type value / Subtype value)." Upon receiving the probe request, the base station 10 executes the process of step S11.

[0048] In the process of step S11, the base station 10 transmits a probe response to the terminal 20. The probe response is a signal that the base station 10 uses to respond to a probe request from the terminal 20. The Frame Control field of the probe response contains, for example, "00 / 0101 (Type value / Subtype value)." Upon receiving the probe request, the terminal 20 executes the process of step S12.

[0049] In the process of step S12, the terminal 20 transmits a multilink association request to the base station 10 via at least one STA function. The multilink association request is a signal for requesting the base station 10 to establish a multilink. For example, the multilink association request is generated by the link management unit 220 of the terminal 20. The Frame Control field of the multilink association request contains, for example, "00 / xxxx (Type value / Subtype value (xxxx is a predetermined numerical value))". Upon receiving the multilink association request, the link management unit 120 of the base station 10 executes the process of step S13.

[0050] In the process of step S13, the link management unit 120 of the base station 10 executes a multi-link association process using one STA function. Specifically, the base station 10 first executes an association process of a first STA function with the terminal 20. Then, when a wireless connection (link) is established in the first STA function, the link management unit 120 of the base station 10 executes an association process of a second STA function using the first STA function with which the link is established. In other words, the STA function with which the link is established is used in the association process of the STA function with 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.

[0051] Note that a multilink may be established when a link is established in the first STA function. For example, the base station 10 and the terminal 20 can simultaneously execute association for the multilink by notifying each other of their multilink capabilities, the links to be multilinked, and the operation parameters for each link prior to the association process. Specifically, when the first STA function starts association, the link management units 120 and 220 instruct the establishment of a multilink and specify the links to be multilinked. Then, the link management units 120 and 220 execute association for each link and manage these links as a multilink.

[0052] In the process of step S14, the link management unit 120 of the base station 10 updates the link management information 121. In this example, the process of step S14 is executed after two links are established, but the link management information 121 may be updated every time the link status is updated, or may be updated when a multi-link is established. Once a multi-link is established and the link management information is updated, the base station 10 executes the process of step S15.

[0053] 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 that the base station 10 uses to respond to a multi-link request from the terminal 20. The Frame Control field of the multi-link association request contains, for example, "00 / 0001 (Type value / Subtype value)". Based on the reception of the multi-link establishment response, the link management unit 220 of the terminal 20 recognizes that a multi-link with the base station 10 has been established. When the terminal 20 receives the multi-link establishment response, it executes the process of step S16.

[0054] In the process of step S16, the link management unit 220 of the terminal 20 updates the link management information 221. That is, the terminal 20 records in the link management information 221 that a multilink with the base station 10 has been established. This completes the multilink process in the wireless system 1 according to the embodiment, and enables data communication using the multilink between the base station 10 and the terminal 20.

[0055] Fig. 9 shows an example of link management information 121 in the wireless system 1 according to the embodiment. Note that the link management information 221 of the terminal 20 contains information similar to the link management information 121 of the base station 10, and therefore a description thereof will be omitted. As shown in Fig. 9, the link management information 121 contains information such as STA function, frequency band, link destination ID, presence or absence of multi-link, and TID.

[0056] In this example, "STA1" corresponds to the STA function using the 6 GHz frequency band, i.e., the radio signal processing unit 150 or 250. "STA2" corresponds to the STA function using the 5 GHz frequency band, i.e., the radio signal processing unit 140 or 240. "STA3" corresponds to the STA function using the 2.4 GHz frequency band, i.e., the radio signal processing unit 130 or 230.

[0057] The link destination ID corresponds to the identifier of the terminal 20 in the link management information 121, and corresponds to the identifier of the base station 10 in the link management information 221. In this example, a multi-link using STA1 and STA2 is established. When a multi-link is established, each of the link management units 120 and 220 transmits data input from an upper layer using the link of at least one STA function associated with the multi-link. In addition, STA1 is set as the primary link, and STA2 is set as the secondary link.

[0058] A primary link is a link used as the main link in a multi-link. A secondary link is a link used as an auxiliary link in a multi-link. The links constituting a multi-link are assigned as either a primary link or a secondary link. There may be two or more primary links and two or more secondary links. For each terminal 20 that has established a multi-link with a base station 10, the link sets constituting each multi-link may be different from each other, and the primary links may also be different from each other. By allowing different primary links, the optimal link between the base station 10 and each terminal 20 can be set as the primary link. This is expected to have the effect of improving the quality of wireless communication.

[0059] Furthermore, the primary link is used for transmitting and receiving the allocated data as well as transmitting and receiving control information related to the operation of the multilink. The primary link is set in advance, for example, when the multilink is established between the base station 10 and the terminal 20. The priority of the STA function used as the primary link may be set according to the frequency band or according to the radio wave strength of the link.

[0060] "TID" in link management information 121 indicates the association between STA functions and TID information. Each STA function transmits and receives data corresponding to the assigned TID information. For example, each of TID#1 to 3 corresponds to LL, VO, VI, BE, or BK. One STA function may be associated with one traffic, i.e., one TID information, or multiple STA functions may be associated with one traffic, i.e., one TID information. In this example, TID#1 is assigned to both STA1 and STA2. TID#2 is assigned to STA1. TID#3 is assigned to STA2.

[0061] A traffic flow corresponding to such an association between traffic and STA functions is set in advance when setting up a multilink between the base station 10 and the terminal 20. For example, the link management unit 220 of the terminal 20 determines the association between traffic and STA functions and requests the link management unit 120 of the base station 10. Then, the base station 10 responds to the request, thereby determining the association between traffic and STA functions.

[0062] Note that traffic is set to be evenly distributed among multiple links constituting a multi-link, for example. This is not limiting, and traffic of similar types (priority / non-priority, etc.) may be collected on one of the links constituting a multi-link. Furthermore, as an association between STA functions and 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 to allocate frequencies used for transmission and reception according to the type of information handled and the data volume.

[0063] <2-2> Data transfer during multi-link Fig. 10 shows an example of a data transmission method in multi-link mode in the base station 10 included in the wireless system 1 according to the embodiment. As shown in Fig. 10, upon receiving data from an upper layer, the base station 10 sequentially executes the processes of steps S20 to S22.

[0064] Specifically, in step S20, the link management unit 120 first acquires TID information corresponding to the data. In other words, the link management unit 120 associates the data with a TID based on, for example, information contained in the header of the data acquired from an upper layer. This allows the link management unit 120 to determine which TID corresponds to the traffic flow of the data.

[0065] Next, in the process of step S21, the link management unit 120 acquires the STA function corresponding to the associated TID information. At this time, the link management unit 120 checks 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 120 may be one or more.

[0066] Next, in the process of step S22, the link management unit 120 outputs data to the acquired STA function. If one STA function is associated with the output data (traffic), the data is transmitted serially using the one STA function. On the other hand, if multiple STA functions are associated with the traffic, the data is transmitted in parallel using the multiple STA functions.

[0067] When one traffic stream is transmitted in parallel, data allocation and rearrangement are performed between the link management unit 120 of the base station 10 and the link management unit 220 of the terminal 20. Data allocation is performed by the link management unit on the transmitting side, and data rearrangement is performed by the link management unit on the receiving side. For example, the link management unit on the transmitting side adds a flag indicating multi-link and an identification number to the wireless frame. The link management unit on the receiving side rearranges the data based on the added flag and identification number.

[0068] Furthermore, in the wireless system 1 according to the embodiment, when a plurality of pieces of data are received from an upper layer, the link management unit may aggregate the received plurality of pieces of data. Aggregation in multi-link may be used as an optional function that can be selected by the user.

[0069] <2-3> Multi-link power save In the wireless system 1 according to the embodiment, multiple types of operation modes are provided for each STA function. Examples of operation modes of the STA function include an active mode, an intermittent operation mode, and a dormant operation mode. The active mode corresponds to a state in which the STA function of the terminal 20 maintains an awake state, thereby enabling wireless signals to be transmitted and received at any time. The intermittent operation mode corresponds to a state in which the STA function of the terminal 20 operates intermittently, by repeatedly switching between an awake state and a dormant state. The dormant operation mode corresponds to a state in which the STA function of the terminal 20 maintains a dormant state, thereby disabling wireless signals from being transmitted and received. The multiple STA functions constituting the multilink include at least one link in the active mode or the intermittent operation mode. The other links constituting the multilink can be set to any of the active mode, the intermittent operation mode, and the dormant operation mode.

[0070] The Awake state corresponds to a state in which radio signals can be transmitted and received. The Dose state corresponds to a state in which radio signals cannot be transmitted or received. In the Doze state, the power supply to the circuitry related to the STA function is appropriately cut off. Therefore, the power consumption of the STA function decreases in the order of active mode, intermittent operation mode, and dormant operation mode. Note that there may also be links that the base station 10 or the terminal 20 can use for communication but that are not included in the link set of the multilink between them (disabled links). In the following, for simplicity of explanation, a link in active mode or intermittent operation mode, i.e., a link that is capable of communication, will be referred to as an "STA function (link) in the Awake state." A link in dormant operation mode, i.e., a link in a power-saving state in which communication is not possible, will be referred to as an "STA function (link) in the Dose state."

[0071] In the multilink in the wireless system 1 according to the embodiment, the STA function set in the primary link is set to, for example, either active mode or discontinuous operation mode. Meanwhile, the STA function set in the secondary link can be set to either active mode, discontinuous operation mode, or dormant mode. For example, the terminal 20 can operate in a power-saving manner by setting the secondary link to dormant mode during multilink. Hereinafter, the multilink state in which the secondary link is set to dormant mode is referred to as "multilink power save." Note that when a multilink is established by multilink processing, the initial state of the secondary link may be set to any of active mode, intermittent operation mode, or dormant mode.

[0072] Fig. 11 shows an example of a method for using multilink power save in the wireless system 1 according to the embodiment. In the initial state of this example, the link state shown in Fig. 9 is set. STA1 and STA2 are each set to active mode. As shown in Fig. 11, when STA1 and STA2 are each in active mode, both data of TID#2 and data of TID#3 can be transmitted and received.

[0073] When the link management unit 220 of the terminal 20 detects that the first condition is satisfied, it transmits a Doze transition notification signal to the access point AP using the primary link (STA1) (step S30). The first condition corresponds to, for example, no traffic accumulating on the secondary link (STA2). The Doze transition notification signal is a signal notifying of a transition to the Doze state, and corresponds to "disable" shown in the figure. The terminal 20 can learn information about the traffic by receiving a beacon signal from the base station 10 using at least one of STA1 and STA2.

[0074] When STA1 of the base station 10 receives the Doze transition notification signal, the link management unit 120 of the base station 10 checks whether or not it is possible to permit the secondary link to transition to the dormant mode. If it is possible to permit the secondary link to transition to the dormant mode, the link management unit 220 of the terminal 20 transmits a positive response ("OK") to the terminal 20 via STA1 or STA2 (step S31). Note that if it is not possible to permit the secondary link to transition to the dormant mode, the link management unit 120 of the base station 10 may transmit a negative response ("NO") to the base station 10 via STA1 or STA2.

[0075] When the terminal 20 receives the positive response in step S31, the link management unit 220 of the terminal 20 changes the STA2 set as the secondary link to a dormant mode (Doze state) (step S32). As a result, the STA1 and STA2 of the terminal 20 enter the Awake state and the Doze state, respectively. At this time, the multilink is in a state where only data of TID#2 can be transmitted and received.

[0076] Thereafter, when the link management unit 220 of the terminal 20 detects that the second condition has been satisfied, it transmits an Awake transition request signal to the access point AP using the primary link (STA1) (step S33). The Awake transition request signal is a signal requesting a transition to an Awake state, and corresponds to "enable" shown in the figure. The second condition corresponds to, for example, the accumulation of traffic on the secondary link (STA2). The terminal 20 can learn information about the traffic by receiving a beacon signal from the base station 10 using STA1 in an active state.

[0077] When STA1 of the base station 10 receives the Awake transition request signal, the link management unit 120 of the base station 10 transmits an acknowledgment ("OK") to the terminal 20 via STA1 corresponding to the primary link (step S34). When the terminal 20 receives the acknowledgment of step S34, the link management unit 220 of the terminal 20 changes STA2, which is set as the secondary link, to active mode (step S35). This causes each of STA1 and STA2 of the terminal 20 to enter the Awake state. As a result, the multilink becomes capable of transmitting and receiving any data of, for example, TID#1 to 3.

[0078] Fig. 12 shows an example of changes in link management information 121 due to the use example of multilink power save described in Fig. 11. As shown in Fig. 12, multilink power save is turned on / off by a Doze transition notification signal and an Awake transition request signal, respectively. Specifically, after multilink is established, terminal 20 transmits a Doze transition notification signal to base station 10, causing the secondary link in active mode to transition to dormant mode, and transmits an Awake transition request signal, causing the secondary link in dormant mode to transition to active mode.

[0079] As described above, in the wireless system 1 according to the embodiment, the base station 10 and the terminal 20 can change the operation mode of the secondary link by transmitting an Awake transition request signal / Doze transition notification signal. The transmission of the Awake transition request signal is performed using the primary link or another active link. The transmission of the Doze transition notification signal is performed using the primary link or a link to be stopped (a link to be transitioned to a dormant mode).

[0080] The Awake transition request signal and the Doze transition notification signal may be transmitted from either the access point AP or the terminal 20. When the first and second conditions are based on traffic congestion (buffer state), the change of the operation mode is triggered, for example, by the traffic accumulated in the buffer exceeding a predetermined threshold. Also, an intermittent operation mode may be applied to the primary link. In this case, the primary link operates so as to be able to receive a beacon signal including at least multi-link control information.

[0081] <2-4> Link start / stop processing The wireless system 1 according to the embodiment can control the activation / deactivation of secondary links based on predetermined conditions during multi-link operation. Hereinafter, the process of activating a secondary link will be referred to as a link activation process. The process of deactivating a secondary link will be referred to as a link deactivation process. In this embodiment, it is assumed that one TID is associated with two links, a primary link and a secondary link, and the primary link is used as the main link.

[0082] (About link activation process) First, an example of a condition for executing the link activation process will be described. Fig. 13 is a flowchart showing an example of an execution condition for the link activation process in the wireless system 1 according to the embodiment. When only the primary link is in the active mode during multi-link, the link management units 120 and 220 execute the series of processes shown in Fig. 13.

[0083] Specifically, first, each of the link management units 120 and 220 monitors the amount of buffered data assigned to the TID for transmission, and checks whether the amount of buffered data exceeds a predetermined threshold (step S40).

[0084] If the amount of buffered data exceeds a predetermined threshold, an Awake transition request signal is transmitted between the link management unit 120 of the base station 10 and the link management unit 220 of the terminal 20, and the secondary link in the Doze state is woken up (step S41). In other words, by executing the link activation process, the STA function of the terminal 20 set as the secondary link transitions from the dormant mode to the active mode. Thereafter, one of the link management units 120 and 220 transmits data using the multiple links (primary link and secondary link) constituting the multilink (step S42).

[0085] On the other hand, if the amount of buffered data does not exceed the predetermined threshold, either of the link management units 120 and 220 transmits the data using the primary link (step S43). In other words, either of the link management units 120 and 220 transmits the data by using the multilink essentially as a single link. Each of the link management units 120 and 220 performs the above-described process when data assigned for transmission to the multilink is buffered.

[0086] (About link termination processing) Next, an example of a condition for executing the link stop process will be described. Fig. 14 is a flowchart showing an example of an execution condition for the link stop process in the wireless system 1 according to the embodiment. When multiple links are in active mode during multi-link, the link management units 120 and 220 execute the series of processes shown in Fig. 14.

[0087] Specifically, first, each of the link management units 120 and 220 monitors the amount of buffered data assigned to the TID for transmission, and checks whether the amount of buffered data has fallen below a predetermined threshold (step S50).

[0088] If the amount of buffered data is below a predetermined threshold, a Doze transition notification signal is transmitted between the link management unit 120 of the base station 10 and the link management unit 220 of the terminal 20, and the secondary link in active mode is set to doze mode (Doze state) (step S51). In other words, by executing the link stop process, the STA function of the terminal 20 set as the secondary link transitions from active mode to doze mode. Thereafter, either the link management unit 120 or 220 transmits data using the primary link (step S52).

[0089] On the other hand, if the amount of buffered data exceeds a predetermined threshold, either of the link management units 120 and 220 transmits the data using the multiple links (primary link and secondary link) that make up the multilink (step S53). Each of the link management units 120 and 220 performs the above-described process when data assigned for transmission to the corresponding multilink is buffered.

[0090] (Specific examples of link start / stop processing) Next, a specific example of link activation / stop processing will be described with reference to Fig. 15. Fig. 15 is a flowchart showing a specific example of link activation / stop processing in the wireless system 1 according to the embodiment. In the initial state of this example, the link state is set to the Doze state shown in Fig. 12.

[0091] 15, when STA1 and STA2 are in the Awake state and the Doze state, respectively, data can be transmitted and received using STA1. After that, when the link management unit 120 of the base station 10 detects that the "buffer amount > predetermined threshold" is satisfied, it notifies the terminal 20 that the "buffer amount > predetermined threshold" is satisfied, for example, by using a beacon signal (not shown).

[0092] Then, the link management unit 220 of the terminal 20 transmits an Awake transition request signal to the access point AP using the primary link (STA1). When STA1 of the base station 10 receives the Awake transition request signal, if the link management unit 120 of the base station 10 can permit the secondary link to transition to active mode, it transmits an acknowledgment ("OK") to the terminal 20 via the primary link (STA1). When the terminal 20 receives the acknowledgment to the Awake transition request signal, the link management unit 220 of the terminal 20 changes the operation mode of STA2, which is set as the secondary link, from dormant mode to active mode. As a result, each of STA1 and STA2 of the terminal 20 enters the Awake state. In other words, the multilink enters a state in which data can be transmitted and received using both the primary link (STA1) and the secondary link (STA2).

[0093] On the other hand, when STA1 and STA2 are each in active mode, if the link management unit 120 of the base station 10 detects that the "buffer volume < predetermined threshold" has been met, it notifies the terminal 20 that the "buffer volume < predetermined threshold" has been met, for example, using a beacon signal (not shown).

[0094] Then, the link management unit 220 of the terminal 20 transmits a Doze transition notification signal to the access point AP using the primary link (STA1). When STA1 of the base station 10 receives the Doze transition notification signal, if the link management unit 120 of the base station 10 can permit the secondary link to transition to the hibernation mode, it transmits an acknowledgment ("OK") to the terminal 20 via the primary link (STA1) or the secondary link (STA2). When the terminal 20 receives the acknowledgment to the Doze transition notification signal, the link management unit 220 of the terminal 20 changes the operation mode of STA2, which is set as the secondary link, from active mode to hibernation mode. As a result, STA1 and STA2 of the terminal 20 enter the Awake state and the Doze state, respectively. In other words, the multilink enters a state in which data can be transmitted and received using only the primary link (STA1).

[0095] In the link activation process and link deactivation process described above, the predetermined threshold used in the link activation process is set to be equal to or greater than the predetermined threshold used in the link deactivation process. In this way, the predetermined threshold used in the link activation process and the predetermined threshold used in the link deactivation process may be different. By providing a margin for these thresholds, the wireless system 1 can prevent frequent occurrence of link activation processes and link deactivation processes when the amount of buffered data is close to each threshold.

[0096] (Regarding wireless frames used in link startup / shutdown processing) 16 and 17 show specific examples of wireless frames used in the link activation / deactivation process of the wireless system 1 according to the embodiment. Fig. 16 corresponds to a wireless frame transmitted when the access point AP requests the terminal 20 to activate / deactivate a link. Fig. 17 corresponds to a wireless frame returned by the terminal 20 to the access point AP in response to the link activation / deactivation request.

[0097] 16, the Frame Body of the wireless frame requesting a change of the primary link includes, for example, a terminal identifier AID (Association Identifier), a link activation / deactivation request, and an identifier of the next target link. Based on the "link activation / deactivation request," the link management unit 220 of the terminal 20 corresponding to the AID references the "identifier of the target link" and determines whether or not the link can be activated / deactivated.

[0098] When link activation / termination is possible, the Frame Body of the wireless frame corresponding to the response to the link activation / termination request, i.e., the acknowledgement, contains "OK" as shown in Figure 17(a). "OK" corresponds to a bit that notifies that link activation / termination is possible.

[0099] On the other hand, if link activation / deactivation is not possible, the Frame Body of the wireless frame corresponding to the response to the link activation / deactivation request, i.e., a negative response, includes "NO" and "Reason" as shown in Figure 17(b). "NO" corresponds to a bit notifying that link activation / deactivation is not possible. "Reason" corresponds to a bit notifying the reason why link activation / deactivation is not possible. Note that "Reason" may be omitted in the wireless frame corresponding to the response to the link activation / deactivation request.

[0100] <3> Effects of the embodiment According to the wireless system 1 according to the embodiment described above, it is possible to reduce the power consumption of the terminal 20 during multi-link operation. The effects of the wireless system 1 according to the embodiment will be described in detail below.

[0101] Base stations and terminals using wireless LANs may have multiple STA functions, each for a different band used, such as 2.4 GHz, 5 GHz, and 6 GHz. In such wireless systems, a wireless connection is established by selecting one of the multiple STA functions, and data communication is performed between the base station and the terminal. In this case, the unselected STA functions are left unused in the wireless system, even if a base station corresponding to the band of the selected STA function exists.

[0102] In contrast, the wireless system 1 according to the embodiment utilizes multiple STA functions provided in each of the base station 10 and the terminal 20 to establish a multi-link between the base station 10 and the terminal 20. Data communication using the multi-link can use multiple bands in combination, and can fully utilize the functions provided in the wireless LAN device. As a result, the wireless system 1 according to the embodiment can achieve efficient communication and improve communication speed.

[0103] On the other hand, the power consumption of multi-link is higher than that of single-link because multiple STA functions are used in each of base station 10 and terminal 20. From the viewpoint of power saving, it is preferable to use single-link when there is no traffic congestion and to use multi-link when there is traffic congestion.

[0104] Therefore, the wireless system 1 according to the embodiment performs data communication by switching between the single link and the multi-link after the multi-link is established. Specifically, after the multi-link is established, the link management unit 120 of the base station 10 and the link management unit 220 of the terminal 20 exchange an Awake transition request signal / Doze transition notification signal to control the activation / deactivation of the secondary link. Here, "activating the link" corresponds to setting the active mode, and "deactivating the link" corresponds to setting the dormant mode.

[0105] In the wireless system 1 according to the embodiment, activation / deactivation of the secondary link is determined based on the amount of buffered data to be transmitted. For example, when the amount of buffered data is large, high-speed data communication is performed using the multiple links constituting the multilink. On the other hand, when the amount of buffered data is small, only one link (the primary link) of the multiple links constituting the multilink is set to active mode, and the other links (secondary links) are set to inactive mode. In this case, the multilink performs data communication in a state substantially similar to that of a single link.

[0106] As described above, the wireless system 1 according to the embodiment uses a multi-link setting that prioritizes performance when the amount of buffered data is large, and uses a multi-link setting that prioritizes power saving when the amount of buffered data is small. As a result, the wireless system 1 according to the embodiment can suppress traffic congestion and reduce power consumption of the terminal 20.

[0107] <4> Modifications of the embodiment The execution conditions and usage methods of the link activation / deactivation process described in the embodiment are merely examples. The wireless system 1 according to first to fifth modifications of the embodiment will be described below.

[0108] <4-1> First modified example Fig. 18 is a flowchart showing an example of an execution condition for a link activation process in the first modified example of the embodiment. The flowchart shown in Fig. 18 has a configuration in which step S40 of the flowchart shown in Fig. 13 is replaced with step S60.

[0109] In the process of step S60, either the link management unit 120 or 220 monitors the remaining battery power of the terminal 20 and checks whether the remaining battery power exceeds a predetermined threshold (step S60). If the "remaining battery power>predetermined threshold" is met (step S60, YES), the process proceeds to step S41, and link activation processing is executed. On the other hand, if the "remaining battery power>predetermined threshold" is not met (step S60, NO), the process proceeds to step S43.

[0110] Fig. 19 is a flowchart showing an example of an execution condition for a link stop process in the first modified example of the embodiment. The flowchart shown in Fig. 19 has a configuration in which step S50 of the flowchart shown in Fig. 14 is replaced with step S61.

[0111] In the process of step S61, either the link management unit 120 or 220 monitors the remaining battery power of the terminal 20 and checks whether the remaining battery power has fallen below a predetermined threshold (step S61). If the "remaining battery power<predetermined threshold" is met (step S61, YES), the process proceeds to step S51, and link stop processing is executed. On the other hand, if the "remaining battery power<predetermined threshold" is not met (step S61, NO), the process of step S53 is executed. The other configurations and operations of the wireless system 1 according to the first modified example of the embodiment are the same as those of the embodiment.

[0112] As described above, the remaining battery charge of the terminal 20 may be used as a condition for executing the link activation / deactivation process. In the first modified example of the embodiment, when the remaining battery charge of the terminal 20 is high, a multi-link setting that prioritizes performance is used, and when the remaining battery charge of the terminal 20 is low, a multi-link setting that prioritizes power saving is used. In this way, the wireless system 1 according to the first modified example of the embodiment can reduce the power consumption of the terminal 20 by changing the number of links to be used depending on the remaining battery charge of the terminal 20.

[0113] Furthermore, in the link activation process and link deactivation process described above, the predetermined threshold used in the link activation process is set to be equal to or greater than the predetermined threshold used in the link deactivation process. Thus, the predetermined threshold used in the link activation process and the predetermined threshold used in the link deactivation process may be the same or different. By providing a margin for these thresholds, the wireless system 1 can prevent frequent occurrence of link activation processes and link deactivation processes when the remaining battery charge is close to each threshold.

[0114] <4-2> Second modified example Fig. 20 is a flowchart showing an example of an execution condition for a link activation process in a second modified example of the embodiment. The flowchart shown in Fig. 20 has a configuration in which step S40 of the flowchart shown in Fig. 13 is replaced with step S70.

[0115] In the process of step S70, each of the link management units 120 and 220 monitors the total traffic volume (irrespective of TID) assigned to the multilink and checks whether the traffic volume exceeds a predetermined threshold (step S70). The traffic to be monitored is not limited to the total traffic volume, and at least one specific TID may be selected. If the "traffic volume > predetermined threshold" is satisfied (step S70, YES), the process proceeds to step S41, and link activation processing is performed. On the other hand, if the "traffic volume > predetermined threshold" is not satisfied (step S70, NO), the process proceeds to step S43.

[0116] Fig. 21 is a flowchart showing an example of an execution condition for a link stop process in a second modified example of the embodiment. The flowchart shown in Fig. 21 has a configuration in which step S50 of the flowchart shown in Fig. 14 is replaced with step S71.

[0117] In the process of step S71, each of the link management units 120 and 220 monitors the traffic volume allocated to the multilink and checks whether the traffic volume has fallen below a predetermined threshold (step S71). If the "traffic volume<predetermined threshold" is met (step S71, YES), the process proceeds to step S41, where link stop processing is executed. On the other hand, if the "remaining battery capacity<predetermined threshold" is not met (step S71, NO), the process proceeds to step S53.

[0118] Note that the "predetermined threshold" used in this modification is set, for example, for each traffic type. In this case, the processes of steps S70 and S71 described above are each executed for each traffic type. For example, each of the link management units 120 and 220 executes a link activation process based on the determination of step S70 corresponding to at least one traffic type among the multiple traffic types being "YES." Similarly, each of the link management units 120 and 220 executes a link termination process based on the determination of step S71 corresponding to at least one traffic type among the multiple traffic types being "YES." The other configurations and operations of the wireless system 1 according to the second modification of the embodiment are the same as those of the embodiment.

[0119] As described above, the traffic volume may be used as a condition for executing the link activation / deactivation process. In the second modification of the embodiment, when the traffic volume is high, a multi-link setting that prioritizes performance is used, and when the traffic volume is low, a multi-link setting that prioritizes power saving is used. In this way, the wireless system 1 according to the second modification of the embodiment can obtain the same effect as the embodiment by changing the number of links to be used depending on the traffic volume.

[0120] Furthermore, in the link activation process and link deactivation process described above, the predetermined threshold used in the link activation process is set to be equal to or greater than the predetermined threshold used in the link deactivation process. Thus, the predetermined threshold used in the link activation process and the predetermined threshold used in the link deactivation process may be the same or different. By providing a margin for these thresholds, the wireless system 1 can prevent frequent occurrence of link activation processes and link deactivation processes when the traffic volume is close to each threshold.

[0121] <4-3> Third modified example Fig. 22 is a flowchart showing an example of an execution condition for a link activation process in a third modified example of the embodiment. The flowchart shown in Fig. 22 has a configuration in which steps S40 and S42 of the flowchart shown in Fig. 13 are replaced with steps S80 and S82, respectively.

[0122] In the process of step S80, each of the link management units 120 and 220 checks whether or not there is important traffic among the traffic accumulated in the multilink. If there is important traffic (step S80, YES), the process proceeds to the process of step S41, where a link activation process is executed, and the important traffic is transmitted using the woken-up secondary link in the process of the subsequent step S81. On the other hand, if there is no important traffic (step S80, NO), the process proceeds to the process of step S43.

[0123] Fig. 23 is a flowchart showing an example of an execution condition for a link stop process in a second modified example of the embodiment. The flowchart shown in Fig. 23 has a configuration in which steps S50 and S53 of the flowchart shown in Fig. 14 are replaced with steps S82 and S83, respectively.

[0124] In the process of step S82, each of the link management units 120 and 220 checks whether there is any important traffic among the traffic accumulated in the multilink. If there is no important traffic (step S82, YES), the process proceeds to the process of step S51, and link stop processing is executed. On the other hand, if there is important traffic (step S82, NO), the important traffic is transmitted using the secondary link in the process of step S83.

[0125] The "important traffic" used in this modification is set to, for example, Low Latency (LL) traffic. Important traffic is not limited to LL traffic as long as it is traffic for which high reliability is required from a higher level. Other important traffic includes, for example, traffic containing payment information and authentication information. Other configurations and operations of the wireless system 1 according to the third modification of the embodiment are the same as those of the embodiment.

[0126] As described above, the presence or absence of important traffic may be used as a condition for executing the link activation / deactivation process. In the third modification of the embodiment, when important traffic is present, the secondary link is used only for transmitting the important traffic, and when there is no important traffic, a multi-link setting that prioritizes power saving is used. In this way, the wireless system 1 according to the third modification of the embodiment can improve the communication quality of important traffic by using the secondary link exclusively for important traffic.

[0127] <4-4> Fourth modified example The wireless system 1 according to the fourth modification of the embodiment relates to a control method when the base station 10 establishes a multi-link with each of a plurality of terminals 20. The following describes an example in which the base station 10 establishes a multi-link with each of the terminals 20A and 20B. In this example, the same channel is assigned to STA1 of the terminal 20A and STA1 of the terminal 20B, and the same channel is assigned to STA2 of the terminal 20A and STA2 of the terminal 20B.

[0128] 24 is a flowchart showing a specific example of link activation / deactivation processing in a wireless system 1 according to a fourth modification of the embodiment. In the initial state of this example, STA1 is set to the primary link and STA2 is set to the secondary link in each of the terminals 20A and 20B. STA1 and STA2 of the terminal 20A are set to the Awake state and the Doze state, respectively, and STA1 and STA2 of the terminal 20B are set to the Awake state.

[0129] 24, when the access point AP detects LL traffic, it transmits a beacon signal including information indicating the presence of LL traffic from the terminal 20A, and the beacon signal is received by the primary links (STA1) of the terminals 20A and 20B. Then, the STA1 of the terminal 20A transmits an Awake transition request signal to the access point AP, and the access point AP returns an acknowledgment to the STA1 of the terminal 20A. As a result, the STA2 of the terminal 20A transitions from the dormant mode to the active mode, and the STA2 of the terminal 20A becomes able to transmit LL traffic.

[0130] Thereafter, when the access point AP detects LL traffic in STA2 of the terminal 20A, it transmits a beacon signal including information indicating the presence of LL traffic from the terminal 20A, and the beacon signal is received by the primary links (STA1) of the terminals 20A and 20B. Then, STA1 of the terminal 20B transmits a Doze transition notification signal to the access point AP, and the access point AP returns an acknowledgement to STA1 of the terminal 20B. As a result, STA2 of the terminal 20B transitions from the active mode to the dormant mode.

[0131] As a result, STA2 of terminal 20B, which is competing for the channel with STA2 of terminal 20A, stops using the channel and enters a Doze state. This allows STA2 of terminal 20A to exclusively use the allocated channel. The wireless system 1 according to the fourth modification of the embodiment can improve the communication quality of LL traffic by exclusively using the secondary link channel allocated to LL traffic in this way.

[0132] Fig. 25 shows a specific example of a wireless frame used in link activation / deactivation processing in the wireless system 1 according to the fourth modification of the embodiment, and corresponds to the beacon signal shown in Fig. 24. As shown in Fig. 25, the Frame Body of the wireless frame including information indicating the presence or absence of LL traffic includes, for example, a terminal identifier AID (Association Identifier), information indicating the presence or absence of Low Latency usage, and an identifier of the target link.

[0133] For example, if the AID included in the beacon signal is different from its own AID, the link management unit 220 of each terminal 20 checks whether low latency is being used (whether LL traffic is present). If the link management unit 220 detects that low latency is being used, it checks whether the channel corresponding to the target link identifier matches the channel used in its own multilink. If the link management unit 220 detects a match between the channels, it executes link stop processing for the secondary link corresponding to that channel. This allows the wireless system 1 to execute the operation described with reference to FIG. 24.

[0134] In the above description, the secondary link channel used for transmitting LL traffic is set to be exclusively used based on the presence or absence of LL traffic, but this is not limiting. For example, other important traffic may be used instead of LL traffic. Multiple types of the set of information shown in Figure 25 may be included in one beacon signal.

[0135] <4-5> Fifth modified example A wireless system 1 according to a fifth modification of the embodiment establishes a multilink similar to that of the embodiment using multiple channels CH included in the same frequency band. The multilink processing in the fifth modification of the embodiment is the same as that of the multilink processing in the embodiment, except that the channels used for the multilink are changed to multiple channels CH included in the same frequency band.

[0136] Fig. 26 shows an example of frequency bands used for wireless communication in a wireless system 1 according to a fifth modification of the embodiment. As shown in Fig. 26, for example, the 2.4 GHz band, the 5 GHz band, and the 6 GHz band are used in wireless communication. Each frequency band includes multiple channels. In this example, it is assumed that the 2.4 GHz band, the 5 GHz band, and the 6 GHz band each include at least three channels CH1, CH2, and CH3. Communication using each channel CH is realized by an associated STA function.

[0137] Fig. 27 shows an example of link management information 121 in a wireless system 1 according to a fifth modification of the embodiment. As shown in Fig. 27, the link management information 121 in the fifth modification of the embodiment has a configuration in which information on a channel ID for each frequency band is added to the link management information 121 in the embodiment. In this example, a multi-link similar to that in the embodiment is established using a channel CH2 of "STA1" corresponding to the 6 GHz frequency band and a channel CH3 of "STA2" corresponding to the 6 GHz frequency band.

[0138] As described above, the STA functions of the base station 10 and the terminal 20 may use the same frequency band. A multilink between the base station 10 and the terminal 20 may be established by a plurality of STA functions using the same frequency band. Specifically, a plurality of STA functions may configure a multilink using different channels CH in the 5 GHz band, for example. Even in such a case, the wireless system 1 according to the fifth modification of the embodiment can achieve efficient communication and reduce power consumption, similar to the embodiment.

[0139] <5> others Although the third modification of the embodiment illustrates an example in which important traffic is allocated to a secondary link, the present invention is not limited to this. Fig. 28 shows an example of data allocation in a multilink of a wireless system according to the third modification of the embodiment. When important traffic is detected, various data may be allocated to a primary link and a secondary link, as shown in Fig. 28. The first example illustrates a case in which the previous traffic is allocated to the primary link, and the increased traffic is allocated to the secondary link. The second example illustrates a case in which traffic with a large data size (e.g., TCP traffic) is allocated to the primary link, and traffic with a small data size (e.g., ACK) is allocated to the secondary link. In this way, in a multilink, data allocation between the primary link and the secondary link may be appropriately set based on the activation of the secondary link.

[0140] The embodiment and each modification can be combined with each other. FIG. 29 shows an example of execution conditions for link stop processing in a wireless system 1 according to a combination of the embodiment and the first modification of the embodiment. As shown in FIG. 29, the determination of step S50 described in the embodiment is first performed, and if the determination of step S50 is "NO," the determination of step S61 described in the first modification of the embodiment may be performed. In this case, if the determination of step S61 is "YES," the process proceeds to, for example, step S51. In this way, the link start / stop processing may be performed by combining two or more of the above-described embodiment and each modification, and the respective effects of the combined embodiment and modification can be obtained.

[0141] In the embodiment, each STA function may notify the corresponding link management unit when it is unable to maintain a link due to, for example, movement of the terminal 20. Furthermore, the link management unit 220 of the terminal 20 may change the state of the multilink with the link management unit 120 of the base station 10 based on the notification from the STA function. Specifically, for example, the link management unit 220 of the terminal 20 and the link management unit 120 of the base station 10 may appropriately change the STA function used in the multilink. When the state of the multilink is changed, the link management units 120 and 220 update the link management information 121 and 221, respectively. Furthermore, the link management units 120 and 220 may update the association between traffic and STA functions according to an increase or decrease in the number of links.

[0142] In the embodiment, a case where the terminal 20 requests the base station 10 to establish a multi-link in the multi-link processing has been exemplified, but the present invention is not limited to this. For example, the base station 10 may request the terminal 20 to establish a multi-link based on the establishment of multiple links between the base station 10 and the terminal 20. In the embodiment and each modification, the "predetermined threshold" used in the link activation processing and the "predetermined threshold" used in the link deactivation processing may be the same or different.

[0143] In the embodiment, the case where the primary link and the secondary link are each set to the active mode after the multi-link process has been described as an example, but this is not limiting. When the multi-link is established, it is sufficient that at least the primary link is set to the active mode, and the secondary link may be set to either the active mode or the dormant mode. The secondary link may be switched between the dormant mode and the active mode based on a predetermined condition.

[0144] The configuration of the wireless system 1 according to the embodiment is merely an example, and other configurations are also possible. For example, although the base station 10 and the terminal 20 each have three STA functions (wireless signal processing units), the present invention is not limited to this. The base station 10 only needs to have at least two wireless signal processing units. Similarly, the terminal 20 only needs to have at least two wireless signal processing units. The number of channels that each STA function can process can be set appropriately depending on the frequency band used. Each of the wireless communication modules 14 and 24 may support wireless communication in multiple frequency bands using multiple communication modules, or may support wireless communication in multiple frequency bands using a single communication module.

[0145] Furthermore, 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 be named and grouped differently as long as they are capable of performing the operations described in each embodiment. For example, in the base station 10, the data processing unit 110 and the link management unit 120 may be collectively referred to as a data processing unit. Similarly, in the terminal 20, the data processing unit 210 and the link management unit 220 may be collectively referred to as a data processing unit.

[0146] Furthermore, 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, an MPU (Micro Processing Unit) or the like may be used instead of a CPU. Furthermore, each of the processes described in each embodiment may be realized by dedicated hardware. The wireless system 1 according to each embodiment may include a mixture of processes executed by software and processes executed by hardware, or may include only one of them.

[0147] In each embodiment, the flowcharts used to explain the operations are merely examples. The order of the operations explained in the embodiments may be changed as far as possible, and other processes may be added. Furthermore, the radio frame formats explained in the above embodiments are merely examples. The radio system 1 may use other radio frame formats as long as they are capable of executing the operations explained in each embodiment.

[0148] The present invention is not limited to the above-described embodiments, and various modifications can be made in the implementation stage without departing from the spirit of the invention. Furthermore, the embodiments may be implemented in appropriate combinations, in which case the combined effects can be obtained. Furthermore, the above-described embodiments include various inventions, and various inventions can be extracted by combining selected elements from the disclosed elements. For example, if the problem can be solved and the desired effect can be obtained even if some elements are deleted from all elements shown in the embodiments, the configuration from which these elements are deleted can be extracted as an invention. [Explanation of symbols]

[0149] 1...Radio 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 110, 210...Data processing unit 120,220...Link Management Department 121,221...Link management information 122,222...Association processing section 123,223...Authentication processing section 124...Data Categorization Department 125...Transmission queue 126...CSMA / CA execution unit 127...Data collision management unit 130, 140, 150, 230, 240, 250...Radio signal processing unit

Claims

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, sets the first radio signal processing unit as a primary link to be used as a main link in the multi-link, and sets the second radio signal processing unit as a secondary link to be used as an auxiliary link in the multi-link, When the secondary link is in an active mode and a first condition is satisfied in the multi-link, the link management unit sets the secondary link to a sleep mode that consumes less power than the active mode; When the secondary link is in the dormant mode, if a second condition is satisfied in the multi-link, the link management unit sets the secondary link to the active mode.

2. the first condition corresponds to a buffer amount of data to be transmitted being less than a first threshold; the second condition corresponds to a buffer amount of data to be transmitted being greater than a second threshold; the first threshold is less than or equal to the second threshold; The base station of claim 1 .

3. the first condition corresponds to a remaining battery charge of the terminal being below a third threshold; the second condition corresponds to a remaining battery charge of the terminal being greater than a fourth threshold; the third threshold is equal to or less than the fourth threshold; The base station of claim 1 .

4. the first condition corresponds to data transmitted over the multilink not including important traffic; the second condition corresponds to the important traffic being included in the data transmitted through the multilink; The base station of claim 1 .

5. When the important traffic is included in the data to be transmitted through the multilink, the link management unit transmits the important traffic using the secondary link of the terminal, and sets the secondary link of another terminal that uses the same channel as the secondary link of the terminal to the operation suspension mode. The base station according to claim 4.

6. 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, sets the first radio signal processing unit as a primary link to be used as a main link in the multi-link, and sets the second radio signal processing unit as a secondary link to be used as an auxiliary link in the multi-link, When the secondary link is in an active mode and a first condition is satisfied in the multi-link, the link management unit sets the secondary link to a sleep mode that consumes less power than the active mode; When the secondary link is in the dormant mode, if a second condition is satisfied in the multi-link, the link management unit sets the secondary link to the active mode.

7. the first condition corresponds to a buffer amount of data to be transmitted being less than a first threshold; the second condition corresponds to a buffer amount of data to be transmitted being greater than a second threshold; the first threshold is less than or equal to the second threshold; The terminal according to claim 6.

8. the first condition corresponds to a remaining battery charge of the terminal being below a third threshold; the second condition corresponds to a remaining battery charge of the terminal being greater than a fourth threshold; the third threshold is equal to or less than the fourth threshold; The terminal according to claim 6.

9. the first condition corresponds to data transmitted over the multilink not including important traffic; the second condition corresponds to the important traffic being included in the data transmitted through the multilink; The terminal according to claim 6.

10. when receiving a radio frame indicating that a secondary link of another terminal using the same channel as the secondary link of the terminal transmits the important traffic, the link management unit sets the secondary link of the terminal to the dormant mode; The terminal according to claim 9.

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