Access point and terminal device

Abstract

An access point according to an embodiment of the present invention comprises a communication circuit and a processor. The communication circuit is configured to transmit and receive wireless signals. The processor is configured to establish a single link or multiple links with each of a plurality of terminal devices by using the communication circuit, and terminate a portion of the established multiple links or add a link to the established multiple links, on the basis of the attributes of the plurality of terminal devices.

Description

Access point and terminal device

[0001] The embodiments relate to an access point and a terminal device.

[0002] A wireless local area network (LAN) is known as a communication system that wirelessly connects an access point (AP) and a terminal device. By using the wireless LAN, the terminal device can access a network via the access point.

[0003] IEEE 802.11be mentions multi-link transmission, in which multiple links (transmission paths) with different frequency channels are established between a terminal device and an access point. In multi-link transmission, multiple affiliated access points (AP_MLDs) equipped in the same housing, called access point multi-link devices (AP_MLDs), and multiple affiliated STAs (STAs) equipped in the same housing, called non-AP_MLDs (non-access point multi-link devices), form pairs and communicate. The AP_MLDs can add and remove devices (links), and can fixedly configure multi-links with as many affiliated APs as possible.

[0004] EVGENY KHOROV et al., "Current Status and Directions of IEEE 802.11be, the Future Wi-Fi 7", IEEE Access Journal, VOLUME 8, May 21, 2020

[0005] However, IEEE802.11be does not specify the specific process required for an AP_MLD to release a device. If a single STA exists in addition to a non-AP_MLD as a terminal device belonging to the AP_MLD and communication resources are evenly distributed, both the uplink traffic and the downlink traffic of the AP_MLD will be dominated by non-AP_MLD traffic. In this case, it is expected that the traffic of a terminal device (single STA) that does not support multi-link transmission will be reduced, and it will not be possible to ensure fairness in communication between each terminal device belonging to the AP_MLD.

[0006] The present invention has been made in light of the above circumstances, and its purpose is to provide an access point and terminal device that can ensure priority and fairness among terminal devices under an access point that supports multi-link.

[0007] An access point according to an embodiment includes a communication circuit and a processor. The communication circuit is configured to transmit and receive wireless signals. The processor is configured to use the communication circuit to establish a single link or multiple links with each of a plurality of terminal devices, and to remove some of the established multiple links or add a link to the established multiple links based on attributes of the plurality of terminal devices.

[0008] According to the embodiment, it is possible to provide an access point and a terminal device that can ensure priority and fairness of terminal devices under the control of an access point that supports multi-link.

[0009] FIG. 1 is a block diagram showing an example of the overall configuration of a communication system according to the first embodiment. FIG. 2 is a block diagram showing an example of the hardware configuration of an access point included in the communication system according to the first embodiment. FIG. 3 is a block diagram showing an example of the hardware configuration of a terminal device included in the communication system according to the first embodiment. FIG. 4 is a block diagram showing an example of the functional configuration of an access point included in the communication system according to the first embodiment. FIG. 5 is a block diagram showing an example of the functional configuration of a terminal device included in the communication system according to the first embodiment. FIG. 6 is a block diagram showing an example of the functional configuration of a terminal device included in the communication system according to the first embodiment. FIG. 7 is a flowchart showing an example of link management processing of an access point included in the communication system according to the first embodiment. FIG. 8 is a schematic diagram showing a first specific example of link management processing in the communication system according to the first embodiment. FIG. 9 is a schematic diagram showing a first specific example of link management processing in the communication system according to the first embodiment. FIG. 10 is a schematic diagram showing a second specific example of link management processing in the communication system according to the first embodiment. FIG. 11 is a schematic diagram showing a second specific example of link management processing in the communication system according to the first embodiment. FIG. 12 is a schematic diagram showing an example of the overall configuration of a communication system according to the second embodiment. FIG. 13 is a flowchart showing an example of destination selection processing for a terminal device included in the communication system according to the second embodiment. Fig. 14 is a schematic diagram for explaining a specific example of the destination selection process in the communication system according to the second embodiment. Fig. 15 is a schematic diagram for explaining a specific example of the destination selection process in the communication system according to the second embodiment. Fig. 16 is a schematic diagram for explaining a specific example of the destination selection process in the communication system according to the second embodiment.

[0010] Each embodiment will be described below with reference to the drawings. Each embodiment illustrates an apparatus or method for embodying the technical idea of ​​the invention. The drawings are schematic or conceptual. Hereinafter, the same reference numerals are used to designate components having substantially the same functions and configurations. Letters and "hyphen + number" following a reference numeral are used to distinguish between elements having similar configurations and referenced by the same reference numeral. Hereinafter, "access point" will be abbreviated to "AP" as appropriate. In this specification, a wireless LAN access point may be referred to as a "base station." A terminal device associated with an access point may be referred to as an "associated terminal." "Multilink transmission" may be referred to as "multilink."

[0011] <1> First Embodiment In a communication system 1 according to a first embodiment, an access point can establish multiple links or single links for each of a plurality of terminal devices. The access point is configured to switch links depending on the status of the plurality of terminal devices to which it belongs. Details of the communication system 1 according to the first embodiment will be described below.

[0012] <1-1> Configuration First, the configuration of the communication system 1 according to the first embodiment will be described. In the first embodiment, a case will be described in which multiple terminal devices belonging to an access point include a terminal device that has established a single link and a terminal device that has established a multi-link.

[0013] <1-1-1> Overall Configuration of Communication System 1 Fig. 1 is a block diagram showing an example of the overall configuration of a communication system 1 according to the first embodiment. As shown in Fig. 1, the communication system 1 includes, for example, an access point 10, a terminal device 20, and a terminal device 30. In this example, the access point 10 and the terminal device 30 each support multilink, which uses multiple channels (links), as a communication method. On the other hand, the terminal device 20 does not support multilink, but supports single link, which uses a single channel.

[0014] The access point 10 is a type of wireless LAN access point. The access point 10 is connected to the network NW by wire or wirelessly and configured to communicate by wire or wirelessly with a server (not shown) on the network NW. The access point 10 is also connected wirelessly to each of the terminal devices 20 and 30 and configured to communicate wirelessly with each of the terminal devices 20 and 30.

[0015] The access point 10 includes, for example, an access point multi-link device (AP_MLD) and multiple affiliated APs (A-APs). The AP_MLD is a multi-link device (MLD) that manages the link status and wireless communication of each of the multiple A-APs. The AP_MLD can execute a process for establishing a single link between the access point 10 and the terminal device 20 and a process for establishing a multi-link between the access point 10 and the terminal device 30. Each A-AP corresponds to a wireless signal processing unit that can establish a wireless link with at least one of the terminal devices 20 and 30. In this example, the access point 10 includes multiple A-APs, A-AP1, A-AP2, and A-AP3.

[0016] Each of the terminal devices 20 and 30 is a wireless terminal such as a smartphone or a PC (Personal Computer). Each of the terminal devices 20 and 30 is located in an area where it can communicate with the access point 10. Each of the terminal devices 20 and 30 is wirelessly connected to the access point 10 and configured to communicate wirelessly with the access point 10.

[0017] The terminal device 20 includes, for example, a link management unit and a single affiliated station (A-STA). The link management unit manages the link state and wireless communication of the single A-STA. The link management unit can execute processing for establishing a single link between the access point 10 and the terminal device 20. The A-STA corresponds to a wireless signal processing unit that can establish a wireless link with the access point 10. In this example, the terminal device 20 includes A-STA0 as the single A-STA.

[0018] The terminal device 30 includes, for example, a non-AP_MLD (non-access point multi-link device) and multiple A-STAs. The non-AP_MLD is an MLD that manages the link status and wireless communication of each of the multiple A-STAs. The non-AP_MLD may also perform processing for establishing a multi-link between the access point 10 and the terminal device 30. In this example, the terminal device 30 includes A-STA1, A-STA2, and A-STA3 as the multiple A-STAs.

[0019] In this example, A-AP1 of the access point 10 has established a link L0 with A-STA0 of the terminal device 20 and a link L1 with A-STA1 of the terminal device 30. A-AP2 of the access point 10 has established a link L2 with A-STA2 of the terminal device 30. A-AP3 of the access point 10 has established a link L3 with A-STA3 of the terminal device 30. In a multi-link connection, different channels are assigned to A-AP1 to A-AP3. Note that the same frequency band may be used for A-AP1 to A-AP3, or different frequency bands may be used. A multi-link may use two or more links. The access point 10 may include two or more A-APs. The terminal device 30 may include two or more A-STAs.

[0020] The wireless communication used in the communication system 1 complies with, for example, the IEEE 802.11 standard. The IEEE 802.11 standard has wireless communication functions based on the OSI (Open Systems Interconnection) reference model. In the OSI reference model, wireless communication functions are divided into seven layers (Layer 1: Physical Layer, Layer 2: Data Link Layer, Layer 3: Network Layer, Layer 4: Transport Layer, Layer 5: Session Layer, Layer 6: Presentation Layer, and Layer 7: Application Layer). The data link layer includes a Logical Link Control (LLC) sublayer and a Media Access Control (MAC) sublayer. Frequency bands used in the wireless communication of the communication system 1 include, for example, the 2.4 GHz band, the 5 GHz band, the 6 GHz band, the 45 GHz band, and the 60 GHz band. Multiple channels are assigned to each frequency band.

[0021] <1-1-2> Hardware Configuration of Communication System 1 The hardware configuration of the communication system 1 according to the first embodiment will be described below.

[0022] 2 is a block diagram showing an example of a hardware configuration of the access point 10 included in the communication system 1 according to the first embodiment. As shown in FIG. 2, the access point 10 includes, for example, a central processing unit (CPU) 11, a read-only memory (ROM) 12, a random access memory (RAM) 13, a wireless communication module 14, and a wired communication module 15.

[0023] The CPU 11 is a processor capable of executing various programs and controls the overall operation of the access point 10. The ROM 12 is, for example, a non-volatile semiconductor memory that stores programs and control data for controlling the access point 10. The RAM 13 is, for example, a volatile semiconductor memory that is used as a work area for the CPU 11. The wireless communication module 14 is a communication circuit configured to be able to send and receive wireless signals via an antenna. The wired communication module 15 is a circuit used to send and receive data, etc., via wired signals and is configured to be connectable to a network NW.

[0024] The access point 10 may have other hardware configurations. For example, the access point 10 may be wirelessly connected to the network NW. In this case, the wired communication module 15 may be omitted from the access point 10. The antenna may be built into the access point 10 or may be externally connected.

[0025] (2: Hardware Configuration of Terminal Device 20) Fig. 3 is a block diagram showing an example of the hardware configuration of the terminal device 20 included in the communication system 1 according to the first embodiment. As shown in Fig. 3, the terminal device 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.

[0026] The CPU 21 is a processor capable of executing various programs and controls the overall operation of the terminal device 20. The ROM 22 is, for example, a non-volatile semiconductor memory and stores programs and control data for controlling the terminal device 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 communication circuit configured to be able to send and receive wireless signals via an antenna. The display 25 displays, for example, a GUI (Graphical User Interface) of application software. The storage 26 is a non-volatile storage device and stores system software and the like for the terminal device 20.

[0027] The terminal device 20 may have other hardware configurations. For example, if the terminal device 20 is an IoT (Internet of Things) terminal or the like, the display 25 may be omitted from the terminal device 20. The antenna may be built into the terminal device 20 or may be externally connected. The hardware configuration of the terminal device 30 is the same as that of the terminal device 20, except that the terminal device 30 supports multilink, for example.

[0028] <1-1-3> Functional Configuration of Communication System 1 The functional configuration of the communication system 1 according to the first embodiment will be described below.

[0029] (1: Functional Configuration of Access Point 10) Fig. 4 is a block diagram showing an example of the functional configuration of the access point 10 included in the communication system 1 according to the first embodiment. As shown in Fig. 4, AP_MLD includes a data allocation unit 110 and a management unit 120. A-AP1, A-AP2, and A-AP3 each include a frame processing unit 130 and a transceiver unit 140. The frame processing unit 130 and transceiver unit 140 of each A-AP are configured in the same way. For this reason, the following description will focus on pairs of frame processing units 130 and transceiver units 140 included in the same A-AP.

[0030] The data allocating unit 110 outputs input data, etc. to a predetermined output destination. For example, the data allocating unit 110 outputs data input from an upper layer to the associated A-AP. The data allocating unit 110 outputs data input from the A-AP to the upper layer. The data allocating unit 110 outputs management information and control information input from the upper layer or the A-AP to the management unit 120. The data allocating unit 110 outputs management information and control information input from the management unit 120 to the upper layer or the associated A-AP.

[0031] The management unit 120 establishes wireless connections (wireless links) between each of the terminal devices 20 and 30, maps data types to links, and performs other operations. The management unit 120 also manages management information related to the link status of the associated terminal devices. The management information may include information related to the attributes and number of associated wireless terminals, information related to user requirements, capabilities, and the like. The management unit 120 may generate information indicating whether or not the link management process described below is available, and may report this information using a beacon signal or the like. The management unit 120 may also transmit information related to the attributes and number of associated wireless terminals as publicly known information.

[0032] The frame processing unit 130 is a functional block that executes processing corresponding to the MAC sublayer of the second layer. When data or the like is input from the data allocation unit 110, the frame processing unit 130 adds a MAC header to generate a MAC frame and outputs the MAC frame to the transceiver unit 140. The frame processing unit 130 can generate a beacon signal based on information input from the management unit 120. Furthermore, when a MAC frame is input from the transceiver unit 140, the frame processing unit 130 processes the MAC header and outputs the MAC frame to the data allocation unit 110.

[0033] The transceiver 140 is a functional block that executes processing corresponding to the first layer. The transceiver 140 generates a wireless frame by adding a preamble or the like to the MAC frame input from the frame processing unit 130, and converts the generated wireless frame into a wireless signal. The transceiver 140 then transmits (radiates) the converted wireless signal via an antenna. The transceiver 140 also extracts a MAC frame from the wireless frame received by the antenna and outputs the extracted MAC frame to the frame processing unit 130.

[0034] (2: Functional Configuration of Terminal Device 20) Fig. 5 is a block diagram showing an example of the functional configuration of the terminal device 20 included in the communication system 1 according to the first embodiment. As shown in Fig. 5, the link management unit of the terminal device 20 includes a frame processing unit 210 and a management unit 220. A-STA0 includes a transmission / reception unit 230.

[0035] The frame processing unit 210 is a functional block that executes processing corresponding to the MAC sublayer of the second layer. When data or the like is input from a higher layer, the frame processing unit 210 adds a MAC header to generate a MAC frame and outputs the MAC frame to the transceiver unit 230. When a MAC frame is input from the transceiver unit 230, the frame processing unit 210 processes the MAC header and outputs the frame to the management unit 220 or a higher layer depending on the frame type.

[0036] The management unit 220 performs operations such as establishing a wireless connection (wireless link) with the access point 10. The management unit 220 can recognize whether the access point 10 can use the link management process described below, based on a beacon signal or the like received from the access point 10. Furthermore, the management unit 220 can select the access point 10 to which the management unit 220 belongs, based on information received from the access point 10, such as whether the link management process can be used.

[0037] The transceiver 230 is a functional block that executes processing corresponding to the first layer. The transceiver 230 generates a wireless frame by adding a preamble or the like to the MAC frame input from the frame processing unit 210, and converts the generated wireless frame into a wireless signal. The transceiver 230 then transmits (radiates) the converted wireless signal via an antenna. The transceiver 230 also extracts a MAC frame from the wireless frame received by the antenna and outputs the extracted MAC frame to the frame processing unit 210.

[0038] (3: Functional Configuration of Terminal Device 30) Fig. 6 is a block diagram showing an example of the functional configuration of the terminal device 30 included in the communication system 1 according to the first embodiment. As shown in Fig. 6, non-AP_MLD includes a data allocation unit 310 and a management unit 320. A-STA1, A-STA2, and A-STA3 each include a frame processing unit 330 and a transceiver unit 340. The frame processing unit 330 and transceiver unit 340 of each A-STA are configured in the same way. For this reason, the following description will focus on the pair of frame processing unit 330 and transceiver unit 340 included in the same A-STA.

[0039] The data allocating unit 310 outputs input data, etc. to a predetermined output destination. For example, the data allocating unit 310 outputs data input from an upper layer to an associated A-STA. The data allocating unit 310 outputs data input from an A-STA to an upper layer. The data allocating unit 310 outputs management information and control information input from an upper layer or an A-STA to the management unit 320. The data allocating unit 310 outputs management information and control information input from the management unit 320 to an upper layer or an associated A-STA.

[0040] The management unit 320 establishes a wireless connection (wireless link) with the access point 10, maps data types to links, and performs other operations. The management unit 320 can also recognize whether the access point AP can use the link management process described below, based on a beacon signal or the like received from the access point. The management unit 320 can then select the access point 10 to which the access point 10 belongs, based on information received from the access point 10, such as whether the link management process can be used.

[0041] The frame processing unit 330 is a functional block that executes processing corresponding to the MAC sublayer of the second layer. When data or the like is input from the data allocation unit 310, the frame processing unit 330 adds a MAC header to generate a MAC frame and outputs the MAC frame to the transceiver unit 340. When a MAC frame is input from the transceiver unit 340, the frame processing unit 330 processes the MAC header and outputs the MAC frame to the data allocation unit 310.

[0042] The transceiver 340 is a functional block that executes processing corresponding to the first layer. The transceiver 340 generates a wireless frame by adding a preamble or the like to the MAC frame input from the frame processor 330, and converts the generated wireless frame into a wireless signal. The transceiver 340 then transmits (radiates) the converted wireless signal via an antenna. The transceiver 340 also extracts a MAC frame from the wireless frame received by the antenna and outputs the extracted MAC frame to the frame processor 330.

[0043] <1-2> Operation Next, a description will be given of the operation of the communication system 1 according to the first embodiment. The operation of the access point 10 described below is executed based on the control of the management unit 120.

[0044] 7 is a flowchart showing an example of a link management process of the access point 10 included in the communication system 1 according to the first embodiment. The access point 10 starts the series of processes shown in FIG. 7 (start) when links are established with multiple terminal devices (20 or 30).

[0045] First, the access point 10 collects information about the associated terminal device (20 or 30) (step S11). In the processing of step S11, the access point 10 collects, for example, the attributes of the associated terminal device (20 or 30) (e.g., whether or not multilink is supported), the number of associated terminal devices (20 or 30), the requirements and capabilities of each terminal device (user), etc. Note that each of the terminal devices 20 and 30 may transmit such information to the access point 10 based on an instruction from the access point 10, may periodically transmit the information to the access point 10, or may transmit the information to the access point 10 when a link is established.

[0046] Next, the access point 10 derives an estimated throughput for each terminal device in multiple link configurations (step S12). Multiple link configurations correspond to various combinations of links configured for the associated terminal devices. Multiple link configurations include, for example, adding a link to an established multi-link or removing some links. When multiple terminal devices (20 or 30) are connected to the same channel, the A-AP equally distributes its own throughput to the multiple terminal devices. The estimated throughput of a terminal device using a multi-link corresponds to the total throughput of the multiple A-APs assigned to the multi-link. In this way, the access point 10 can derive an estimated throughput for each terminal device in each link configuration based on the throughput for each A-AP and the number of terminal devices (20 or 30) connected to each A-AP.

[0047] Next, the access point 10 determines whether link switching is necessary (step S13). Specifically, the access point 10 determines whether an A-AP needs to be released or an A-AP needs to be added. The access point 10 may determine whether link switching is necessary based on a comparison of the estimated throughput information for each configuration derived in step S12 and whether predetermined conditions are met. If link switching is necessary, the access point 10 may then determine which links to release from the established multilink or which links to add to the established multilink. Examples of these predetermined conditions include an estimated throughput ratio between terminal devices being within 1:2 or an estimated throughput per terminal device being 50 Mbps or greater. Note that "release of an A-AP" corresponds to releasing a link using at least one A-AP from among multiple A-APs used in multilink. "Addition of an A-AP" corresponds to adding a link with a terminal device 30 that supports multilink. In other words, adding a link corresponds to an increase in the number of A-AP-A-STA pairs used in multilink.

[0048] If the access point 10 determines in the process of step S13 that link switching is not necessary (step S14: NO), the series of processes in FIG. 7 ends (END).

[0049] If the access point 10 determines in the processing of step S13 that link switching is necessary (step S14: YES), it executes link switching (step S15). For example, if a link between a single A-STA (terminal device 20) and a non-AP_MLD (terminal device 30) is established with a certain A-AP, the access point 10 releases the link between the A-AP and the non-AP_MLD. As a result, the access point 10 allows one of the subordinate terminal devices 20 that has established a single link to occupy the link released from the multi-link. Note that in this case, the access point 10 has already confirmed in the processing of step S13 that the terminal device 30 with the reduced number of non-AP_MLD links will satisfy the requirements of the terminal device 30 after link switching. Furthermore, when an A-AP that has been released from a link with a single A-STA (terminal device 20) is available for multi-link use, the access point 10 may add a link between the A-AP and the non-AP_MLD. When the link switching is complete, the access point 10 ends the series of processes shown in FIG. 7 (end).

[0050] Below, a first specific example and a second specific example of link management processing in the communication system 1 according to the first embodiment will be described in order. In each of the first and second specific examples, the access point 10 establishes a single link with one terminal device 20 and multiple links with two terminal devices 30-1 and 30-2. In this example, the throughputs of A-AP1, A-AP2, and A-AP3 are 60 Mbps, 100 Mbps, and 100 Mbps, respectively. A-AP1 has established a link L0 with A-STA0 of the terminal device 20, a link L1-1 with A-STA1 of the terminal device 30-1, and a link L1-2 with A-STA1 of the terminal device 30-2. A-AP2 has established a link L2-1 with A-STA2 of the terminal device 30-1, and a link L2-2 with A-STA2 of the terminal device 30-2. A-AP3 has established a link L3-1 with A-STA3 of terminal device 30-1 and a link L3-2 with A-STA3 of terminal device 30-2. The necessary conditions for estimated throughput are set as (1) a ratio between terminals (devices) of 1:2 or less, and (2) 50 Mbps or more per terminal (device).

[0051] (First specific example) Figures 8 and 9 are schematic diagrams showing a first specific example of the link management process in the communication system 1 according to the first embodiment. Figures 8 and 9 correspond to the states before and after execution of the link management process in the first specific example, respectively.

[0052] As shown in FIG. 8, the throughput of A-AP1 is 20 Mbps per terminal device because 60 Mbps is equally distributed among three terminal devices (links L0, L1-1, and L1-2). The throughput of A-AP2 is 50 Mbps per terminal device because 100 Mbps is equally distributed among two terminal devices (links L2-1 and L2-2). The throughput of A-AP3 is 50 Mbps per terminal device because 100 Mbps is equally distributed among two terminal devices (links L3-1 and L3-2). Therefore, the estimated throughputs of terminal devices 20, 30-1, and 30-2 are 20 Mbps, 20 + 50 + 50 = 120 Mbps, and 20 + 50 + 50 = 120 Mbps, respectively. In this state, the estimated throughput of terminal device 20 does not satisfy the necessary conditions for estimated throughput. Therefore, the access point 10 switches the link configuration shown in FIG. 8 through the link management process.

[0053] Specifically, as shown in FIG. 9 , the access point 10 disconnects the link that used the same A-AP1 as the link L0 of the terminal device 20 in the multilink with each of the terminal devices 30-1 and 30-2. In other words, the access point 10 disconnects both the link L1-1 with the terminal device 30-1 and the link L1-2 with the terminal device 30-2. In other words, the access point 10 releases the A-AP1 from the AP_MLD of the access point 10. As a result, the A-AP1 of the access point 10 is occupied by the A-STA0 of the terminal device 20, and the estimated throughput of the terminal device 20 becomes 60 Mbps. In this way, the access point 10 can have one of the associated terminals, the terminal device 20 with which a single link has been established, occupy the link released from the established multilink. Meanwhile, the estimated throughput of each of the terminal devices 30-1 and 30-2 becomes 100 Mbps due to the reduction in the number of A-STAs constituting the multilink. In this way, the access point 10 can satisfy the estimated throughput requirements for each of the terminal devices 20, 30-1 and 30-2 through the link management process.

[0054] 10 and 11 are schematic diagrams showing a second specific example of the link management process in the communication system according to the first embodiment. Figures 10 and 11 correspond to the states before and after execution of the link management process in the second specific example, respectively.

[0055] As shown in Fig. 10, the state before execution of the link management process of the second specific example is the same as the state after execution of the link management process of the first specific example shown in Fig. 9. The second specific example describes a case where, from this state, the terminal device 20 stops using the access point 10 and the link L0 is disconnected. In this example, when the access point 10 executes the link management process, it determines whether the A-AP 1, from which the link L0 has been disconnected, can be used for the multilink of the terminal devices 30-1 and 30-2 that belong to the access point 10.

[0056] Thereafter, as shown in FIG. 11 , the access point 10 adds A-AP1 to each of the multilinks with the terminal device 30-1 and 30-2, establishing links L1-1 and L1-2 ("Link Addition" in FIG. 11 ). In other words, the access point 10 adds A-AP1 to the AP_MLD of the access point 10. Then, the throughput of A-AP1 is 30 Mbps per device, with 60 Mbps being evenly distributed between the two terminal devices (links L0, L1-1, and L1-2). As a result, the estimated throughputs of the terminal devices 30-1 and 30-2 are 30 + 50 + 50 = 130 Mbps and 30 + 50 + 50 = 130 Mbps, respectively. In this way, the access point 10 can increase the estimated throughput of the terminal device 30 using the multilink depending on the status of the multiple terminal devices associated with it.

[0057] <1-3> Effects of the First Embodiment As described above, in the communication system 1 according to the first embodiment, the access point 10 releases or adds A-APs included in the AP_MLD based on the status of the terminal device (20 or 30) to which it belongs. For example, by releasing a link, the access point 10 can suppress traffic of the non-AP_MLD (terminal device 30) and ensure traffic of a single A-STA (terminal device 20). Furthermore, for example, when the link of a single A-STA is released, the access point 10 can increase the throughput of the non-AP_MLD by adding a link.

[0058] As described above, the communication system 1 according to the first embodiment can ensure fairness in communications between terminal devices even when a single A-STA (terminal device 20) exists in addition to a non-AP_MLD (terminal device 30) as a terminal device belonging to the access point 10. Therefore, the communication system 1 according to the first embodiment can ensure priority and fairness for terminal devices subordinate to the access point 10 that supports multi-link. Furthermore, the communication system 1 according to the first embodiment can set a more preferable throughput for each terminal device depending on the status of the terminal device to which it belongs.

[0059] <2> Second Embodiment A communication system 1A according to the second embodiment relates to a terminal device 20 that selects an access point 10 to which it belongs, taking into consideration whether the link management process described in the first embodiment is valid. Details of the second embodiment will be described below, focusing on differences from the first embodiment.

[0060] 12 is a schematic diagram showing an example of the overall configuration of a communication system 1A according to the second embodiment. The communication system 1A includes, for example, access points 10-1 and 10-2 and a terminal device 20A. Although not shown in the figure, the communication system 1A may also include the terminal device 30 described in the first embodiment.

[0061] Each of the access points 10-1 and 10-2 has a configuration similar to that of the access point 10 described in the first embodiment. Each of the access points 10-1 and 10-2 is configured to be able to execute the link management process described in the first embodiment. Each of the access points 10-1 and 10-2 is configured to broadcast (disseminate) information INFO to nearby terminal devices. The information INFO may include information indicating whether the link management process described in the first embodiment is enabled for the access point itself, information regarding the throughput of A-APs available for wireless connection, and the like. The information INFO may include the status of each A-AP within the access point itself, the configuration of the AP_MLD, the status of the associated terminal devices, and the like. For example, a beacon signal is used to broadcast the information INFO. Whether the link management process is enabled may be indicated by the SSID (Service Set Identifier) ​​of the access point 10. In other words, the SSID may be used to notify the control type of the access point 10.

[0062] The terminal device 20A is configured to detect two or more surrounding access points 10 and select an access point 10 to which it is to belong based on whether the detected access points 10 use a control method for releasing a portion of an established multilink in accordance with the attributes of the associated terminal. The remaining configuration of the terminal device 20A is the same as that of the terminal device 20. The following description will be given of a case in which the terminal device 20A is disposed so as to be included in both the communication area CA_AP1 of the access point 10-1 and the communication area CA_AP2 of the access point 10-2. The terminal device 30, not shown, is the same as that of the first embodiment. The number of access points 10, terminal devices 20, and terminal devices 30 included in the communication system 1A may be any other number. The communication system 1A may also include an access point that does not support link management processing. The remaining configuration of the communication system 1A according to the second embodiment is the same as that of the communication system 1 according to the first embodiment.

[0063] <2-2> Operation The operation of the communication system 1A according to the second embodiment will be described below. The operation of the terminal device 20A described below is executed based on the control of the management unit 220.

[0064] 13 is a flowchart showing an example of a destination selection process of the terminal device 20A included in the communication system 1A according to the second embodiment. When attempting to establish a link connection with the access point 10, the terminal device 20A starts the series of processes shown in FIG. 13 (start).

[0065] First, the terminal device 20A collects information about surrounding access points 10 (step S21). The terminal device 20A receives information INFO from surrounding access points 10, for example, using a beacon signal. This allows the terminal device 20A to know whether the access point 10 that transmitted the beacon signal is using the control of the first embodiment (whether it is valid or not), whether it supports the control of the first embodiment, and so on. This "control of the first embodiment" corresponds to the link management process described in the first embodiment. The terminal device 20A may detect whether each access point 10 is using the control of the first embodiment based on the SSID.

[0066] Next, the terminal device 20A selects an access point 10 to which it will belong, taking into consideration whether or not the control of the first embodiment is being used (step S22). For example, the terminal device 20A preferentially selects an access point 10 that uses the control of the first embodiment as its destination. Note that an access point 10 that uses the control of the first embodiment may indicate to the terminal device 20A the throughput of A-APs that can be used for wireless connection, taking into consideration the case where some of the multilinks of other terminal devices 30 have been released. In this case, the terminal device 20A may select a more preferable access point 10 to which it will belong, based on the information regarding the throughput indicated by each access point 10. In this way, the terminal device 20A may at least indirectly consider whether or not the control of the first embodiment is being used when selecting an access point 10 to which it will belong.

[0067] A specific example of the destination selection process in the communication system 1A according to the second embodiment will be described below. In this example, the access point 10-1 forms a multilink including links L1-1, L2-1, and L3-1 with the terminal device 30-1, and forms a multilink including links L1-2, L2-2, and L3-2 with the terminal device 30-2. In this example, the throughputs of A-AP1, A-AP2, and A-AP3 are 60 Mbps, 100 Mbps, and 100 Mbps, respectively. The access point 10-2 includes A-AP4, and the throughput of A-AP4 is 50 Mbps.

[0068] 14, 15, and 16 are schematic diagrams for explaining a specific example of the destination selection process in the communication system 1A according to the second embodiment. FIG. 14 shows the state of the communication system 1A at the start of the destination selection process. FIG. 15 shows a case where the destination selection process is executed when the access point 10-1 does not use the control of the first embodiment. FIG. 16 shows a case where the destination selection process is executed when the access point 10-1 uses the control of the first embodiment. In this specific example, it is assumed that the access point 10-2 does not use the control of the first embodiment.

[0069] 14, when the destination selection process starts, each of the access points 10-1 and 10-2 broadcasts information INFO, for example, by a beacon signal. Then, A-STA0 of the terminal device 20A receives the information INFO of the access point 10-1 via A-AP1, and receives the information INFO of the access point 10-2 via A-AP4. This allows the management unit 220 of the terminal device 20A to know whether each of the access points 10-1 and 10-2 is using the control of the first embodiment.

[0070] When the access point 10-1 does not use the control of the first embodiment, the throughput of A-AP1 that the access point 10-1 can assign to the terminal device 20A is 20 Mbps. On the other hand, the throughput of A-AP4 that the access point 10-2 can assign to the terminal device 20A is 50 Mbps, which is greater than the throughput of A-AP1. Therefore, as shown in FIG. 15, the terminal device 20A selects the access point 10-2 with the greater throughput, and establishes a link L4 with A-AP4 of the access point 10-2 using A-STA0 (link establishment in FIG. 15).

[0071] When the access point 10-1 uses the control of the first embodiment, the throughput of A-AP1 that the access point 10-1 can allocate to the terminal device 20A is 60 Mbps. On the other hand, the throughput of A-AP4 that the access point 10-2 can allocate to the terminal device 20A is 50 Mbps, which is smaller than the throughput of A-AP1. Therefore, as shown in FIG. 16, the terminal device 20A selects the access point 10-1 with the higher throughput, and establishes a link L0 with A-AP1 of the access point 10-1 using A-STA0 (link establishment in FIG. 16).

[0072] <2-3> Advantages of the Second Embodiment As described above, in the communication system 1A according to the second embodiment, the terminal device 20A that is not connected to an access point 10 refers to the information INFO made known by the surrounding access points 10 and uses this as a reference when selecting an access point 10 to which to belong. This allows the terminal device 20A in the communication system 1A according to the second embodiment to select a more preferable access point 10 to which to belong. As a result, the communication system 1A according to the second embodiment can ensure fairness in communications, as in the first embodiment, and can further improve the throughput of the terminal device 20A.

[0073] <3> Others The conversion process from radio frames to radio signals described in the above embodiments includes, for example, convolutional coding, interleaving, subcarrier modulation, inverse fast Fourier transform, OFDM modulation, and frequency conversion. The conversion process from radio signals to radio frames described in the above embodiments includes, for example, frequency conversion, OFDM demodulation, fast Fourier transform, subcarrier demodulation, deinterleaving, and Viterbi decoding. A wireless communication standard other than the IEEE 802.11 standard may be used as the wireless communication standard.

[0074] In the above-described embodiments, the CPU 11 of the access point 10 and the CPU 21 of the terminal devices 20 and 30 may each be other circuits. For example, the access point 10 and the terminal devices 20 and 30 may each include an MPU (Micro Processing Unit) or the like instead of a CPU. Each of the processes described in each embodiment may be realized by dedicated hardware. The processes of the access point 10 and the terminal device 20 may be a mixture of processes executed by software and processes executed by hardware, or may be only one of them.

[0075] 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.

[0076] REFERENCE SIGNS LIST 1, 1A... communication system 10, 10-1, 10-2... access point 20, 20A, 30, 30-1, 30-2... terminal device 11, 21... CPU 12, 22... ROM 13, 23... RAM 14, 24... wireless communication module 15... wired communication module 25... display 26... storage 110, 310... data distribution unit 120, 220, 320... management unit 130, 210, 330... frame processing unit 140, 230, 340... transmission / reception unit

Claims

1. An access point comprising: a communication circuit configured to transmit and receive wireless signals; and a processor configured to use the communication circuit to establish a single link or multiple links with each of a plurality of terminal devices, and to remove some of the established multiple links or add a link to the established multiple links based on attributes of the plurality of terminal devices.

2. The access point according to claim 1, wherein the attributes include information indicating whether multilink is supported.

3. The access point of claim 1, wherein the processor is further configured to estimate the throughput of each of the plurality of terminal devices in a plurality of types of link configurations based on the attributes, and to determine a link to be removed from the established multi-link or a link to be added to the established multi-link.

4. The access point according to claim 1, wherein the processor is further configured to cause one of the plurality of terminal devices that has established a single link to occupy the link released from the established multi-link.

5. The access point of claim 1, wherein the processor is further configured to transmit information relating to the attribute as publicly known information via the communication circuitry.

6. A terminal device comprising: a communication circuit configured to transmit and receive wireless signals; and a processor configured to use the communication circuit to detect two or more surrounding access points, and to select an access point to belong to from the two or more access points based on whether the detected access points use a control method for releasing part of an established multi-link according to the attributes of the terminal to which they belong.

7. The terminal device according to claim 6, wherein the processor is further configured to receive information regarding the attributes and number of associated terminals from the detected access point via the communication circuit, and to select an access point to which the terminal is to belong based on the information.

8. The terminal device according to claim 6, wherein the processor is further configured to determine whether or not the control method is being used based on an SSID (Service Set Identifier) of the detected access point.

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