Access point, wireless terminal device, and wireless communication method

Abstract

An access point according to one embodiment is provided with: a first wireless signal processing unit configured to transmit and receive a wireless signal using a microwave band; a second wireless signal processing unit configured to transmit and receive a wireless signal using a millimeter band; and a management unit that manages a first wireless link between the first wireless signal processing unit and the terminal and a second wireless link between the second wireless signal processing unit and the terminal. When the communication quality of the second wireless link becomes lower than a predetermined first reference when the second wireless link is in a state in which the second wireless link is used for data communication, the management unit switches the second wireless link to a state in which the second wireless link is not used for data communication. When the communication quality of the second wireless link becomes superior to a predetermined second reference when the second wireless link is not used for data communication, the second wireless link is switched to be used for data communication.

Description

Technical Field

[0001] This invention relates to wireless communication. Background Technology

[0002] Wireless LANs (Local Area Networks) are known as communication systems that wirelessly connect access points to wireless terminal devices. The IEEE 802.11 standard is widely used for wireless LANs.

[0003] As a successor to IEEE 802.11ax, the IEEE 802.11be standard currently under development will specify multi-link transmission using multiple transmission paths (wireless links) with different frequency channels for frame transmission.

[0004] On the other hand, among the major standards following IEEE 802.11be, there is an exploration of using frequency bands other than the unlicensed frequency bands available for wireless LANs, namely the microwave band (such as the millimeter wave band).

[0005] Because high-frequency radio waves, such as millimeter waves, have stronger line-of-sight propagation than microwave waves, they are more susceptible to blockage. Therefore, when using millimeter waves for multi-link transmission, attention must be paid to the performance degradation caused by communication quality fluctuations.

[0006] Existing technical documents

[0007] Non-patent literature

[0008] Non-patent literature 1: IEEE 802.11be / D3.0, “35.3 Multi-link operation”, pp. 479-586, January 2023. Summary of the Invention

[0009] The technical problem that the invention aims to solve

[0010] The purpose of this invention is to provide a wireless communication technology in which high-reliability transmission can be achieved even when the communication quality of the wireless link using the millimeter-wave frequency channel is reduced in multi-link transmission using the millimeter-wave band.

[0011] Technical solutions for solving technical problems

[0012] An access point according to one embodiment of the present invention includes: a first wireless signal processing unit configured to transmit and receive wireless signals using a microwave band; a second wireless signal processing unit configured to transmit and receive wireless signals using a millimeter wave band; and a management unit that manages a first wireless link between the first wireless signal processing unit and a wireless terminal device and a second wireless link between the second wireless signal processing unit and the wireless terminal device. When the communication quality of the second wireless link deteriorates below a predetermined first reference while the second wireless link is in a data communication state, the management unit switches the second wireless link to a state not used for data communication; when the communication quality of the second wireless link becomes better than a predetermined second reference while the second wireless link is not used for data communication, the management unit switches the second wireless link to a state used for data communication.

[0013] Invention Effects

[0014] According to the present invention, a technology is provided that enables highly reliable transmission in multi-link transmission using millimeter-wave bands, even when the communication quality of the wireless link using the millimeter-wave band frequency channel is reduced. Attached Figure Description

[0015] Figure 1 This is a block diagram illustrating a communication system according to an embodiment.

[0016] Figure 2 This is a diagram illustrating link management information for an implementation method.

[0017] Figure 3 This is a block diagram illustrating the hardware structure of the access point in an implementation method.

[0018] Figure 4 This is a block diagram illustrating the hardware structure of the terminal according to the implementation method.

[0019] Figure 5 This is a block diagram illustrating the functional structure of the access point in the implementation method.

[0020] Figure 6 This is a block diagram illustrating the functional structure of the auxiliary AP included in the access point of an implementation method.

[0021] Figure 7 This is a block diagram illustrating the functional structure of the terminal in the implementation method.

[0022] Figure 8 The frame format of the association request in the implementation is shown.

[0023] Figure 9 This is a flowchart illustrating the processing of traffic allocation TIDs in an implementation method.

[0024] Figure 10 This is a flowchart illustrating the switching process of a millimeter-wave link according to an implementation method.

[0025] Figure 11 This is a sequence diagram illustrating the steps of switching millimeter-wave links according to an implementation method.

[0026] Figure 12 This is a sequence diagram illustrating the steps of switching millimeter-wave links according to an implementation method.

[0027] Figure 13 This is a flowchart illustrating the process of determining channel switching target candidates according to an implementation method.

[0028] Figure 14 This is a flowchart illustrating the channel switching process of an implementation method.

[0029] Figure Labels

[0030] 10: Access point; 11: CPU; 12: Program memory; 13: RAM; 14: Wireless communication module; 15: Wired communication module; 20: Terminal; 21: CPU; 22: Program memory; 23: RAM; 24: Wireless communication module; 25: Display; 26: Storage device; 30: Communication network; 45: Wireless communication system; 50: Communication system; 110: LLC processing unit; 120: Data processing unit; 130: Upper-level MAC frame processing unit; 140: Management unit; 141: Link management information; 50: Communication Department; 151: Lower-level MAC Frame Processing Department; 152: Wireless Signal Processing Department; 153: Communication Quality Measurement Department; 155: Auxiliary AP; 190: AP-type MLD; 210: LLC Processing Department; 220: Data Processing Department; 230: Upper-level MAC Frame Processing Department; 240: Management Department; 241: Link Management Information; 250: Communication Department; 251: Lower-level MAC Frame Processing Department; 252: Wireless Signal Processing Department; 255: Auxiliary STA; 260: Application Execution Department; 290: Non-AP-type MLD. Detailed Implementation

[0031] The embodiments of the present invention are described below with reference to the accompanying drawings.

[0032] Figure 1 This illustration schematically shows an example of the structure of a communication system 50 including a wireless communication system 45 according to one embodiment. Figure 1 As shown, the communication system 50 includes an access point (AP) 10, a terminal 20, and a communication network 30. The access point 10 and the terminal 20 are included in the wireless communication system 45.

[0033] Access point 10 is a wireless LAN access point. Access point 10 can connect to one or more wireless terminal devices. The number of wireless terminal devices connected to access point 10 changes dynamically. Figure 1 In the example shown, access point 10 is connected to terminal 20, which is a wireless terminal device. Access point 10 establishes one or more wireless links with terminal 20 and uses these established wireless links to communicate with terminal 20. The state in which multiple wireless links are established between access point 10 and terminal 20 is called a multi-link connection. Access point 10 is wired to a communication network 30, which may include the Internet.

[0034] Terminal 20 is a wireless terminal device with wireless communication capabilities, functioning as a wireless LAN client. As an example, the wireless device is implemented using a semiconductor chip and assembled in terminal 20. Examples of wireless terminal devices include smartphones, mobile phones, tablet PCs (personal computers), desktop PCs, laptop PCs, and IoT (Internet of Things) sensors / devices. Terminal 20 accesses communication network 30 via access point 10. For example, terminal 20 exchanges data with a server (not shown) on communication network 30 via access point 10. For example, the server could be a service provider offering services such as online games, exchanging service-related data with terminal 20 via communication network 30.

[0035] The wireless communication between access point 10 and terminal 20 is based on the IEEE 802.11 standard. The IEEE 802.11 standard defines the Layer 1 and Layer 2 MAC (Media Access Control) sublayers in the OSI (Open Systems Interconnection) model. In the OSI model, communication functions are divided into seven layers (Layer 1: Physical Layer, Layer 2: Data Link Layer, Layer 3: Network Layer, Layer 4: Transport Layer, Layer 5: Session Layer, Layer 6: Presentation Layer, Layer 7: Application Layer). The Data Link Layer includes, for example, the LLC (Logical Link Control) sublayer and the MAC sublayer.

[0036] Furthermore, although this specification describes wireless communication based on the IEEE 802.11 standard as an example, wireless communication standards different from the IEEE 802.11 standard may also be used.

[0037] In this embodiment, access point 10 and terminal 20 support multi-link operation. Multi-link operation includes operations such as logically establishing multiple wireless links between the access point and the wireless terminal device. In multi-link operation, the access point and the wireless terminal device communicate with each other through multi-link transmission using the established multiple wireless links. For example, the wireless terminal device performs carrier sensing based on CSMA / CA (Carrier Sense Multiple Access / Collision Avoidance) on each wireless link and sends data frames to the access point through the wireless link that has been granted transmission rights.

[0038] Access point 10 has an AP-type MLD (access point multi-link device) 190. The AP-type MLD 190 has multiple affiliated APs 155 (e.g., affiliated APs 155-1, 155-2, 155-3), which are used to communicate with terminal 20. The affiliated APs 155 represent logical entities that serve as interfaces for the MAC layer and physical layer of the wireless medium.

[0039] The auxiliary APs 155-1 and 155-2 are configured to transmit and receive wireless signals using frequency channels within the microwave band. As part of the microwave band, they can use frequencies such as 2.4 GHz, 5 GHz, and 6 GHz. The auxiliary APs 155-1 and 155-2 can use frequency channels within different frequency bands, or different frequency channels within the same frequency band. The auxiliary AP 155-3 is configured to transmit and receive wireless signals using frequency channels within the millimeter-wave band. As part of the millimeter-wave band, it can use frequencies such as 45 GHz and 60 GHz. The millimeter-wave band is a frequency band higher than the microwave band.

[0040] In addition, the AP type MLD 190 can have at least two auxiliary AP 155s, including an auxiliary AP 155 for processing the microwave band and an auxiliary AP 155 for processing the millimeter wave band.

[0041] Terminal 20 includes a non-AP MLD (non-access point multi-link device) 290. The non-AP MLD 290 has multiple auxiliary STAs 255 (e.g., auxiliary STAs 255-1, 255-2, 255-3), which are used to communicate with access point 10. Each auxiliary STA 255 represents a logical entity serving as an interface between the MAC layer and physical layer for the wireless medium.

[0042] Auxiliary STAs 255-1 and 255-2 are configured to use frequency channels included in the microwave band to transmit and receive wireless signals, while auxiliary STA 255-3 is configured to use frequency channels included in the millimeter-wave band to transmit and receive wireless signals. For example, auxiliary STAs 255-1, 255-2, and 255-3 are controlled to use the same frequency channels as auxiliary APs 155-1, 155-2, and 155-3 for communication with auxiliary APs 155-1, 155-2, and 155-3 of access point 10. In the following text, the frequency channel is also simply referred to as the channel.

[0043] Furthermore, the non-AP type MLD 290 may have at least two auxiliary STA 255s, including an auxiliary STA 255 for processing the microwave band and an auxiliary STA 255 for processing the millimeter-wave band. The number of auxiliary STA 255s included in the non-AP type MLD 290 may differ from the number of auxiliary AP 155s included in the AP type MLD 190.

[0044] This section briefly explains the steps for establishing a link group between access point 10 and terminal 20. Establishing a link group between access point 10 and terminal 20 includes summarizing and establishing multiple possible wireless links between access point 10 and terminal 20.

[0045] Access point 10 periodically broadcasts beacon frames to notify of its existence. A beacon frame is a type of management frame that includes information indicating that access point 10 supports multilink operation and millimeter-wave band communication. Terminal 20 receives the beacon frames from access point 10 and, based on the received beacon frames, identifies that access point 10 supports multilink operation and millimeter-wave band communication.

[0046] Furthermore, terminal 20 can send a probe request to access point 10. Access point 10 receives the probe request from terminal 20 and sends a probe response to terminal 20 as a response to the probe request. The probe response includes information indicating that access point 10 supports multi-link operation and information indicating that access point 10 supports millimeter-wave band communication, etc. In this case, based on the probe response received from access point 10, terminal 20 identifies that access point 10 supports multi-link operation and that access point 10 supports millimeter-wave band communication.

[0047] After receiving a beacon frame or probe response, terminal 20 sends an association request to access point 10 to establish a link group. The association request may include information indicating whether millimeter-wave band communication is used, calibration information for adjusting the radio frequency (RF) of the interface using the millimeter-wave band, identification information for non-AP type MLD 290, identification information for each auxiliary STA 255, and information specifying the connection destination for each auxiliary STA 255. Terminal 20 will use any one of the auxiliary STAs 255-1 and 255-2 in the microwave band for sending the association request.

[0048] Access point 10 receives an association request from terminal 20 and establishes a link group between access point 10 and terminal 20 based on the received association request. For example, access point 10 sets the identification information of affiliated AP 155, which is designated as the connection destination in the association request, as the affiliated STA 255. In addition, access point 10 adjusts the radio frequency of affiliated AP 155-3 based on the calibration information included in the association request.

[0049] Access point 10 sends an association response to terminal 20 as a response to the association request. Access point 10 will use any one of the auxiliary APs 155-1 and 155-2 in the microwave band for sending the association response. For example, when auxiliary AP 155-1 receives an association request from terminal 20, auxiliary AP 155-1 will be used for sending the association response.

[0050] Terminal 20 receives an association response from access point 10. In response to receiving the association response, it sets the identification information and channel of the associated AP 155 as the connection destination for each associated STA 255.

[0051] In this way, a link group is established between access point 10 and terminal 20. Specifically, a wireless link is established between auxiliary AP 155-1 and auxiliary STA 255-1, between auxiliary AP 155-2 and auxiliary STA 255-2, and between auxiliary AP 155-3 and auxiliary STA 255-3. The state in which each auxiliary AP 155 constituting access point 10 and each auxiliary STA 255 constituting terminal 20 establishes an independent connection is called a wireless connection.

[0052] Figure 2 This is a simplified illustration of an example of the link management information maintained by terminal 20. Figure 2 The link management information shown indicates the status of the wireless link between access point 10 and terminal 20. This link management information includes link ID, frequency band information, channel ID, link information, link group information, traffic information, and usage information.

[0053] Link ID is identification information that identifies a wireless link. Frequency band information indicates the frequency band used for the wireless link. Channel ID is identification information that identifies the channel used in the wireless link. Figure 2 In the example shown, terminal 20 is able to use the three wireless links established with access point 10. The wireless link with link ID 1 uses channel CH1 in the 5 GHz band, the wireless link with link ID 2 uses channel CH2 in the 6 GHz band, and the link with link ID 3 uses channel CH3 in the 45 GHz band.

[0054] Link information indicates whether a wireless link has been established. Link group information indicates whether a link group has been established between access point 10 and terminal 20. When a link group has been established, the link information indicates which wireless links constitute the link group. Figure 2 In the example shown, the link group contains three wireless links with link IDs 1 to 3.

[0055] Traffic information represents the TID (Traffic Identifier) ​​assigned to the wireless link. The TID is an identifier representing the type of traffic, and each traffic type can be associated with an access category. Access categories include, for example, VO (Voice), VI (Video), BE (Best-effort), BK (Background), and LL (Low Latency). Figure 2 In the example shown, TID#1 corresponds to any category among VO, VI, BE, and BK, and TID#2 corresponds to LL. TID#2 is assigned to traffic requesting reliable communication, such as traffic requesting low latency. TIDs such as TID#2 assigned to traffic requesting reliable communication are prohibited from being assigned to wireless links using the millimeter wave band. TID#1 is assigned to the three wireless links with link IDs 1 to 3, and TID#2 is assigned to the two wireless links with link IDs 1 and 2.

[0056] Usage information indicates whether a wireless link is available. Usage information is set for wireless links using the millimeter-wave band, but not for those using the microwave band. In this embodiment, wireless links using the millimeter-wave band are set to either an enabled state or a temporarily disabled state. Hereinafter, wireless links using the millimeter-wave band will also be referred to as millimeter-wave links. When a millimeter-wave link is enabled, it is used for data communication. When a millimeter-wave link is disabled, it is not used for data communication.

[0057] like Figure 2 As shown, assuming TID#1 is assigned to three wireless links with link IDs 1 to 3, and the millimeter-wave link is set to active status, a data frame containing data assigned TID#1 is transmitted via the millimeter-wave link (i.e., the wireless link with link ID 3). When the millimeter-wave link switches from active to inactive, the data frame containing data assigned TID#1 is transmitted via a microwave-band wireless link. In this way, the microwave-band wireless link is used as an auxiliary to the millimeter-wave link. Alternatively, when the millimeter-wave link is active, data frames containing data assigned TID#1 can also be transmitted using both the millimeter-wave link and the microwave-band wireless link.

[0058] Any wireless link using the microwave band can be designated as the master link. The wireless link designated as the master link is used to exchange important information such as control information for controlling the millimeter-wave link.

[0059] Access point 10 maintains communication with each wireless terminal device connected to access point 10. Figure 2The link management information illustrated herein is the same as the link management information. That is, the link management information maintained by access point 10 indicates the status of the wireless link between access point 10 and each wireless terminal device connected to access point 10.

[0060] Figure 3 This is a simplified illustration of an example of the hardware structure of access point 10. For example... Figure 3 As shown, as hardware components, access point 10 includes a CPU (Central Processing Unit) 11, a program memory 12, a RAM (Random Access Memory) 13, a wireless communication module 14, and a wired communication module 15. The CPU 11 is connected to the program memory 12, RAM 13, wireless communication module 14, and wired communication module 15 via a bus.

[0061] CPU 11 is an integrated circuit capable of executing various programs and performing information processing. Program memory 12 is a non-volatile semiconductor memory such as ROM (Read-Only Memory) or flash memory, storing programs and data. RAM 13 is, for example, a volatile semiconductor memory, used as the working area of ​​CPU 11. At least a portion of the processing described with respect to access point 10 can be implemented by CPU 11 executing the program stored in program memory 12.

[0062] The wireless communication module 14 is a circuit used to transmit and receive data via wireless signals. The wireless communication module 14 includes... Figure 1 The multiple auxiliary APs 155 shown correspond to multiple wireless communication circuits, and each wireless communication circuit is connected to the antenna corresponding to that wireless communication circuit among multiple antennas. The wired communication module 15 is a circuit used to transmit and receive data via wired signals and is connected to the communication network 30.

[0063] Figure 4 This is a simplified illustration of an example of the hardware structure of terminal 20. For example... Figure 4 As shown, as hardware components, terminal 20 includes CPU 21, program memory 22, RAM 23, wireless communication module 24, display 25, and storage device 26.

[0064] CPU 21 is an integrated circuit capable of executing various programs and performing information processing. Program memory 22 is a non-volatile semiconductor memory such as ROM, which stores programs and data. Storage device 26 can be used as program memory 22. RAM 23 is, for example, a volatile semiconductor memory, used as the working area of ​​CPU 21. At least a portion of the processing described with respect to terminal 20 can be implemented by CPU 21 executing the program stored in program memory 22.

[0065] The wireless communication module 24 is a circuit used to transmit and receive data via wireless signals. The wireless communication module 24 includes... Figure 1The multiple auxiliary STAs 255 shown correspond to multiple wireless communication circuits, each wireless communication circuit being connected to an antenna corresponding to that wireless communication circuit among multiple antennas. The display 25 displays information such as a GUI (Graphical User Interface) provided by application software. The display 25 may function as an input interface for the terminal 20. For example, a touch panel may be provided on the display 25. The storage device 26 is a non-volatile storage device such as an HDD (Hard Disk Drive) or SSD (Solid State Drive) that stores data, including, for example, the system software of the terminal 20.

[0066] Figure 4 The hardware structure shown is one example; terminal 20 can also have the same... Figure 4 The hardware structures shown are different. For example, when terminal 20 is an IoT device, the display 25 can be removed from terminal 20.

[0067] Figure 5 This is a simplified illustration of an example of the functional structure of access point 10. For example... Figure 5 As shown, access point 10 includes an LLC processing unit 110, a data processing unit 120, an upper-level MAC frame processing unit 130, a management unit 140, and a communication unit 150. The data processing unit 120, the upper-level MAC frame processing unit 130, the management unit 140, and the communication unit 150 are contained within... Figure 1 In the AP-type MLD 190 shown, the LLC processing unit 110 can be implemented by a combination of CPU 11 and wired communication module 15. The data processing unit 120, the upper-level MAC frame processing unit 130, the management unit 140, and the communication unit 150 can be implemented by a wireless communication module 14 or a combination of CPU 11 and wireless communication module 14.

[0068] LLC processing unit 110 performs LLC sub-layer processing and upper-level layer (layer 3 to layer 7) processing on the input signals. For example, LLC processing unit 110 receives data from communication network 30, appends DSAP (Destination Service Access Point) and SSAP (Source Service Access Point) headers to the received data to generate LLC data packets, and transmits the generated LLC data packets to data processing unit 120. Additionally, LLC processing unit 110 receives LLC data packets from data processing unit 120, extracts data from the received LLC data packets, and sends the extracted data to communication network 30.

[0069] The data processing unit 120 receives LLC data packets from the LLC processing unit 110, appends a MAC header to the received LLC data packets to generate a MAC frame, and transmits the generated MAC frame to the upper-level MAC frame processing unit 130. Additionally, the data processing unit 120 receives MAC frames from the upper-level MAC frame processing unit 130, extracts LLC data packets from the received MAC frames, and transmits the extracted LLC data packets to the LLC processing unit 110.

[0070] The upper-level MAC frame processing unit 130 receives MAC frames from the data processing unit 120 and transmits the received MAC frames to the communication unit 150. The upper-level MAC frame processing unit 130 can perform predetermined processing on the MAC frames received from the data processing unit 120. For example, the upper-level MAC frame processing unit 130 aggregates multiple MAC frames received from the data processing unit 120 to generate one MAC frame, and transmits that MAC frame to the communication unit 150. Alternatively, the upper-level MAC frame processing unit 130 receives MAC frames from the communication unit 150 and, depending on the type of the received MAC frame, transmits the received MAC frame to the data processing unit 120 or the management unit 140. For example, the upper-level MAC frame processing unit 130 transmits the MAC frame to the data processing unit 120 when the MAC frame is a data frame, and transmits the MAC frame to the management unit 140 when the MAC frame is a management frame or a control frame. The upper-level MAC frame processing unit 130 can perform predetermined processing on the MAC frames received from the communication unit 150. For example, the upper-level MAC frame processing unit 130 de-aggregates the MAC frames received from the communication unit 150 to generate multiple MAC frames, and transmits these MAC frames to the data processing unit 120.

[0071] Communication unit 150 communicates wirelessly with terminal 20. Communication unit 150 is equipped with... Figure 1 The diagram shows multiple auxiliary APs 155 (Auxiliary APs 155-1, 155-2, and 155-3). Each auxiliary AP 155 includes a lower-level MAC frame processing unit 151 and a wireless signal processing unit 152. For example, auxiliary AP 155-i includes a lower-level MAC frame processing unit 151-i and a wireless signal processing unit 152-i, where i is an integer from 1 to 3.

[0072] The lower-level MAC frame processing unit 151 receives MAC frames from the upper-level MAC frame processing unit 130, performs processing on the received MAC frames, including encryption, and transmits them to the wireless signal processing unit 152. Conversely, the lower-level MAC frame processing unit 151 receives MAC frames from the wireless signal processing unit 152, performs processing on the received MAC frames, including decryption, and transmits them to the upper-level MAC frame processing unit 130.

[0073] The wireless signal processing unit 152 is configured to transmit and receive wireless signals. For example, wireless signal processing unit 152-1 is configured to transmit and receive wireless signals using a first channel included in the microwave band, and wireless signal processing unit 152-2 is configured to transmit and receive wireless signals using a second channel included in the microwave band, wherein the first channel and the second channel are different. Wireless signal processing unit 152-3 is configured to transmit and receive wireless signals using a third channel included in the millimeter wave band.

[0074] The wireless signal processing unit 152 performs physical layer processing on the input MAC frames or wireless signals. The wireless signal processing unit 152 receives MAC frames from the lower-level MAC frame processing unit 151, adds preambles and PHY (physical layer) headers to the received MAC frames to generate wireless frames, and converts the wireless frames into wireless signals by performing predetermined modulation processing, which is then radiated via an antenna. Predetermined modulation processing includes, for example, convolutional coding, interleaving, subcarrier modulation, inverse fast Fourier transform (IFFT), OFDM (orthogonal frequency division multiplexing) modulation, and frequency conversion. Additionally, the wireless signal processing unit 152 receives wireless signals from the terminal via the antenna and performs predetermined demodulation processing on the received wireless signals to obtain wireless frames. Predetermined demodulation processing includes, for example, frequency conversion, OFDM demodulation, fast Fourier transform (FFT), subcarrier demodulation, deinterleaving, and Viterbi decoding. Then, the wireless signal processing unit 152 extracts MAC frames from the wireless frames and transmits the extracted MAC frames to the lower-level MAC frame processing unit 151.

[0075] like Figure 6 As shown, the auxiliary AP 155-3 may also include a communication quality measurement unit 153. The communication quality measurement unit 153 measures the received power of the wireless signal from the terminal 20 received by the wireless signal processing unit 152-3 and notifies the management unit 140 of the measurement results. For example, RSSI (Received Signal Strength Indication) is measured as an indicator of the received power. The measurement results of the received power of the wireless signal from the terminal 20 received by the wireless signal processing unit 152-3 are used to evaluate the communication quality of the wireless link (millimeter-wave link) between the wireless signal processing unit 152-3 and the terminal 20.

[0076] Refer again Figure 5 The management unit 140 manages connections with each wireless terminal device. For example, the management unit 140 establishes link groups with the wireless terminal devices via the communication unit 150. Specifically, in response to receiving an association request from terminal 20, the management unit 140 performs association and authentication processing to establish multiple links between access point 10 and terminal 20. After the link group is established, any one or more wireless links included in the link group are used in data exchange between access point 10 and terminal 20.

[0077] The management unit 140 maintains link management information 141 for managing wireless terminal devices connected to access point 10. The link management information 141 is for each wireless terminal device connected to access point 10, including, for example... Figure 2 The information shown.

[0078] Link management information 141 is used by the upstream MAC frame processing unit 130. For example, the upstream MAC frame processing unit 130 uses link management information 141 to distribute MAC frames received from the data processing unit 120 or the management unit 140. Specifically, the upstream MAC frame processing unit 130 refers to link management information 141 according to the TID of the data included in the MAC frame in order to determine which of the affiliated APs 155-1, 155-2, and 155-3 should the MAC frame be transmitted to. For example, in the link management information 141 including... Figure 2 As shown in the information, when the data contained in the MAC frame is assigned TID#2, the upper-level MAC frame processing unit 130 transmits the MAC frame to the auxiliary AP 155-3.

[0079] The management unit 140 transmits (specifically, broadcasts) a beacon frame via the communication unit 150. The beacon frame includes, for example, an identifier for access point 10, capability information, identifiers for each affiliated AP 155, and information indicating the frequency channel and operating parameters of each affiliated AP 155. The identifier for access point 10 is identification information used to identify access point 10, and may be, for example, a MAC address assigned to access point 10. The capability information includes first capability information indicating whether multi-link operation is supported and second capability information indicating whether millimeter-wave band communication is supported. In this embodiment, the first capability information is set to a value indicating support for multi-link operation, and the second capability information is set to a value indicating support for millimeter-wave band communication. The identifier for affiliated AP 155 is identification information used to identify affiliated AP 155, and may be, for example, a MAC address assigned to affiliated AP 155. The operating parameters include, for example, multiple parameters for channel access control such as TXOPlimit.

[0080] Figure 7 This is a simplified illustration of an example of the functional structure of terminal 20. For example... Figure 7 As shown, terminal 20 includes an LLC processing unit 210, a data processing unit 220, an upper-level MAC frame processing unit 230, a management unit 240, a communication unit 250, and an application execution unit 260. The data processing unit 220, the upper-level MAC frame processing unit 230, the management unit 240, and the communication unit 250 are included in... Figure 1In the non-AP type MLD 290 shown, the LLC processing unit 210 and the application execution unit 260 can be implemented by the CPU 21. The data processing unit 220, the upper-level MAC frame processing unit 230, the management unit 240, and the communication unit 250 can be implemented by the wireless communication module 24 or a combination of the wireless communication module 24 and the CPU 21.

[0081] Application Execution Unit 260 Execution and Figure 1 Applications such as data exchange between servers on the communication network 30 shown.

[0082] LLC processing unit 210 performs LLC sub-layer and upper-layer processing on the input signals. For example, LLC processing unit 210 receives data from application execution unit 260, appends DSAP headers and SSAP headers to the received data to generate LLC data packets, and transmits the generated LLC data packets to data processing unit 220. Additionally, LLC processing unit 210 receives LLC data packets from data processing unit 220, extracts data from the received LLC data packets, and transmits the extracted data to application execution unit 260.

[0083] The data processing unit 220 receives LLC data packets from the LLC processing unit 210, appends a MAC header to the received LLC data packets to generate a MAC frame, and transmits the generated MAC frame to the upper-level MAC frame processing unit 230. Additionally, the data processing unit 220 receives MAC frames from the upper-level MAC frame processing unit 230, extracts LLC data packets from the received MAC frames, and transmits the extracted LLC data packets to the LLC processing unit 210.

[0084] The upper-level MAC frame processing unit 230 receives MAC frames from the data processing unit 220 and transmits the received MAC frames to the communication unit 250. The upper-level MAC frame processing unit 230 can perform predetermined processing on the MAC frames received from the data processing unit 220. For example, the upper-level MAC frame processing unit 230 aggregates multiple MAC frames received from the data processing unit 220 to generate one MAC frame, and transmits that MAC frame to the communication unit 250. Alternatively, the upper-level MAC frame processing unit 230 receives MAC frames from the communication unit 250 and, depending on the type of the received MAC frame, transmits the received MAC frame to the data processing unit 220 or the management unit 240. For example, the upper-level MAC frame processing unit 230 transmits the MAC frame to the data processing unit 220 when the MAC frame is a data frame, and transmits the MAC frame to the management unit 240 when the MAC frame is a management frame or a control frame. The upper-level MAC frame processing unit 230 can perform predetermined processing on the MAC frames received from the communication unit 250. For example, the upper-level MAC frame processing unit 230 de-aggregates the MAC frames received from the communication unit 250 to generate multiple MAC frames, and transmits these MAC frames to the data processing unit 220.

[0085] Communication unit 250 communicates wirelessly with access point 10. Communication unit 250 has... Figure 1 The diagram shows multiple auxiliary STAs 255 (auxiliary STAs 255-1, 255-2, and 255-3). Each auxiliary STA 255 includes a lower-level MAC frame processing unit 251 and a wireless signal processing unit 252. For example, auxiliary STA 255-i includes a lower-level MAC frame processing unit 251-i and a wireless signal processing unit 252-i, where the values ​​are integers from 1 to 3.

[0086] The lower-level MAC frame processing unit 251 receives MAC frames from the upper-level MAC frame processing unit 230, performs processing on the received MAC frames including encryption, and transmits them to the wireless signal processing unit 252. Conversely, the lower-level MAC frame processing unit 251 receives MAC frames from the wireless signal processing unit 252, performs processing on the received MAC frames including decryption, and transmits them to the upper-level MAC frame processing unit 230.

[0087] The wireless signal processing unit 252 is configured to transmit and receive wireless signals. For example, wireless signal processing unit 252-1 is configured to transmit and receive wireless signals using a first channel included in the microwave band, and wireless signal processing unit 252-3 is configured to transmit and receive wireless signals using a second channel included in the microwave band, wherein the first channel and the second channel are different. Wireless signal processing unit 252-3 is configured to transmit and receive wireless signals using a third channel included in the millimeter wave band.

[0088] The wireless signal processing unit 252 performs physical layer processing on the input MAC frames or wireless signals. The wireless signal processing unit 252 receives MAC frames from the lower-level MAC frame processing unit 251, adds preambles and PHY headers to the received MAC frames to generate wireless frames, performs predetermined modulation processing to convert the wireless frames into wireless signals, and radiates the wireless signals via an antenna. Additionally, the wireless signal processing unit 252 receives wireless signals from the terminal via an antenna, performs predetermined demodulation processing on the received wireless signals to obtain wireless frames. Then, the wireless signal processing unit 252 extracts MAC frames from the wireless frames and transmits the extracted MAC frames to the lower-level MAC frame processing unit 251.

[0089] Management unit 240 manages the connection with access point 10. For example, management unit 240 receives beacon frames from access point 10 via communication unit 250 and identifies the presence of access point 10 based on the received beacon frames. Based on the capability information contained in the beacon frames received from access point 10, management unit 240 identifies that access point 10 supports multi-link operation and millimeter-wave band communication. Management unit 240 uses either wireless signal processing unit 252-1 or wireless signal processing unit 252-2 to send an association request to access point 10 to establish a link group including millimeter-wave links. The association request includes information indicating whether millimeter-wave band data communication is used, information indicating that a TID (Transmission ID) is allowed to be assigned to the millimeter-wave link, and calibration information required for establishing an interface using the millimeter-wave band. Access point 10 associates wireless links with TIDs based on the information in the association request indicating that a TID is allowed to be assigned to the millimeter-wave link. Access point 10 includes information indicating the association between wireless links and TIDs in the association response.

[0090] Figure 8 This provides a simplified illustration of an example of the frame format for an association request. For example... Figure 8 As shown, information indicating whether millimeter-wave band data communication is used, information indicating the TID that can be assigned to the millimeter-wave link, and calibration information required for setting up the millimeter-wave band interface can be stored as an extension of the Per-STA Profile in the Multi-Link element as specified in the IEEE 802.11be standard.

[0091] Refer again Figure 7 The management unit 240 maintains link management information 241 for managing the access point 10 connected to the terminal 20. The link management information 241 includes, for example... Figure 2 The information shown.

[0092] Link management information 241 is used by the upper-level MAC frame processing unit 230. For example, the upper-level MAC frame processing unit 230 uses link management information 241 to distribute MAC frames received from the data processing unit 220 or the management unit 240. Specifically, the upper-level MAC frame processing unit 230 refers to link management information 241 according to the TID of the data included in the MAC frame in order to determine which of the affiliated STAs 255-1, 255-2, and 255-3 to transmit the MAC frame to. For example, in the link management information 241, which includes... Figure 2 As shown in the information, when the data contained in the MAC frame is assigned TID#2, the upper-level MAC frame processing unit 130 transmits the MAC frame to the auxiliary STA 255-3.

[0093] In addition, the subsidiary STA 255-3 may also have the same Figure 6 The communication quality measurement unit 153 shown is equivalent to a communication quality measurement unit. For example, the communication quality measurement unit of auxiliary STA 255-3 measures the received power of the wireless signal received from the access point by the wireless signal processing unit 252-3, and notifies the management unit 240 of the measurement result. The management unit 240 can receive the measurement result from the auxiliary STA 255 and send the received measurement result to the access point 10. The auxiliary STA 255 that processes the microwave band is used for transmitting the measurement result. For example, the management unit 240 uses auxiliary STA 255-1 or auxiliary STA 255-2 to send the measurement result received from auxiliary STA 255-3 to the access point 10.

[0094] Figure 9 This diagram illustrates an example of how traffic is assigned TIDs. TIDs that are allowed to be assigned to millimeter-wave links and those that are prohibited from being assigned to millimeter-wave links are predefined. For example, TID#1 is defined as a TID allowed to be assigned to millimeter-wave links, while TID#2, TID#3, and TID#4 are defined as TIDs prohibited from being assigned to millimeter-wave links. For example, in terminal 20, TIDs are assigned based on the traffic's identifier or characteristics.

[0095] like Figure 9 As shown, when the traffic is control information (step S901: Yes), the TID corresponding to the control information is assigned to the traffic (step S905). The TID corresponding to the control information is any TID among the TIDs that are prohibited from being assigned to the millimeter-wave link (e.g., TID #4).

[0096] If the traffic is high-reliability traffic (step S902: Yes), the TID corresponding to the high-reliability traffic is assigned to the traffic (step S905). High-reliability traffic refers to traffic that requires reliable communication. For example, high-reliability traffic is traffic that requires low latency. The TID corresponding to the high-reliability traffic is any TID (e.g., TID #2) that is prohibited from being assigned to the millimeter-wave link.

[0097] If the traffic is normal traffic that is neither control information nor high-reliability traffic (step S901: No and step S902: No), the process proceeds to step S903. If the traffic is not transmitted via the millimeter-wave link (step S903: No), a TID corresponding to the normal traffic is assigned to the traffic (step S905). The TID corresponding to the normal traffic is any TID among those prohibited from being assigned to the millimeter-wave link (e.g., TID #3). If the traffic is transmitted via the millimeter-wave link (step S903: Yes), a TID that is allowed to be assigned to the millimeter-wave link (e.g., #1) is assigned to the traffic (step S904).

[0098] Figure 10 This schematically illustrates an example of the process of switching a millimeter-wave link between an active and inactive state. Figure 10 The processing shown is performed by access point 10. Here, it is assumed that a link group is established between access point 10 and terminal 20. Specifically, a wireless link is established between the wireless signal processing unit 152-1 of access point 10 and the wireless signal processing unit 252-1 of terminal 20, a wireless link is established between the wireless signal processing unit 152-2 of access point 10 and the wireless signal processing unit 252-2 of terminal 20, and a wireless link (millimeter-wave link) is established between the wireless signal processing unit 152-3 of access point 10 and the wireless signal processing unit 252-3 of terminal 20.

[0099] If the millimeter-wave link is set to an active state (step S1001: Yes), the process proceeds to step S1002; if the millimeter-wave link is set to an inactive state (step S1001: No), the process proceeds to step S1003.

[0100] First, let's explain the situation where the millimeter-wave link is set to an invalid state.

[0101] In step S1003, the wireless signal processing unit 152-3, under the control of the management unit 140, sends a predetermined number of test frames (e.g., a times) to the terminal 20. The test frames are MAC frames (e.g., data frames) used to determine whether the millimeter-wave link has switched from invalid to valid. When the terminal 20 successfully receives a test frame from the access point 10, it replies with an affirmative response (Ack) frame to the access point 10.

[0102] In step S1004, the management unit 140 determines whether the number of times the Ack frame reception from the terminal 20 has failed exceeds a predetermined value n. For example, the management unit 140 sets a counter to 0 and performs the operation (described below) a predetermined number of times (e.g., a times). The management unit 140 sends a test frame to the terminal 20 using the wireless signal processing unit 152-3. The management unit 140 waits to receive an Ack frame from the terminal 20 for a predetermined time period. When an Ack frame is not received within the predetermined time period, the management unit 140 increments the counter by 1. When an Ack frame is received within the predetermined time period, the management unit 140 keeps the counter constant. The value of the counter after performing the above operation a predetermined number of times indicates the number of times the Ack frame reception from the terminal 20 has failed.

[0103] If the number of Ack frame reception failures exceeds a predetermined value n (step S1004: Yes), the management unit 140 proceeds to step S1006. In step S1006, the management unit 140 keeps the millimeter-wave link in an inactive state as is. After a predetermined time period, the process returns to step S1001.

[0104] On the other hand, if the number of Ack frame reception failures does not exceed a predetermined value n (step S1004: No), the management unit 140 proceeds to step S1005. In step S1005, the management unit 140 determines whether the number of times the RSSI of the wireless signal received by the wireless signal processing unit 152-3 from the terminal 20 is less than a predetermined value m within a predetermined time period is less than a predetermined value x. For example, the management unit 140 measures the RSSI of Ack frames from the terminal 20. Specifically, the management unit 140 sets a counter to 0 and performs the following operations within the predetermined time period. When the wireless signal processing unit 152-3 receives a wireless signal from the terminal 20, the management unit 140 measures the RSSI of the wireless signal and determines whether the measured value of the RSSI is less than a predetermined value m. When the measured value of the RSSI is less than the predetermined value m, the management unit 140 increments the counter by 1, and maintains the counter when the measured value of the RSSI is not less than the predetermined value m. The value of the counter after a predetermined time period indicates the number of times the RSSI of the wireless signal received by the wireless signal processing unit 152-3 from the terminal 20 is less than a predetermined value m during the predetermined time period.

[0105] If the number of times the RSSI of the wireless signal received by the wireless signal processing unit 152-3 from the terminal 20 is less than a predetermined value m is less than a predetermined value x within a predetermined time period (step S1005: Yes), the process proceeds to step S1007. In step S1007, the management unit 140 switches the millimeter-wave link from an invalid state to an active state. Afterward, the process returns to step S1001.

[0106] On the other hand, if the RSSI of the wireless signal received by the wireless signal processing unit 152-3 from the terminal 20 is less than a predetermined value m at least x times within a predetermined time period (step S1005: No), the process proceeds to step S1006. In step S1006, the management unit 140 keeps the millimeter-wave link in an inactive state as is. Afterwards, the process returns to step S1001.

[0107] Next, we will explain the situation where the millimeter-wave link is set to be active.

[0108] If the millimeter-wave link is enabled (step S1001: Yes), the process proceeds to step S1002. In step S1002, the management unit 140 monitors the communication status of the millimeter-wave link. The process proceeds to step S1004.

[0109] In step S1004, when the management unit 140 has sent a data frame or test frame to the terminal 20, it determines whether the number of times the Ack frame has failed to be received from the terminal 20 exceeds a predetermined value n.

[0110] If the number of times the Ack frame reception fails from terminal 20 exceeds a predetermined value n (step S1004: Yes), the process proceeds to step S1006. In step S1006, the management unit 140 switches the millimeter-wave link from an active state to an inactive state. After a predetermined time period, the process returns to step S1001.

[0111] If the number of times the Ack frame reception failure from terminal 20 does not exceed a predetermined value n (step S1004: No), the process proceeds to step S1005. If the number of times the RSSI of the wireless signal received by the wireless signal processing unit 152-3 from terminal 20 is less than a predetermined value m within a predetermined time period is less than a predetermined value x (step S1005: Yes), the process proceeds to step S1007. In step S1007, the management unit 140 maintains the millimeter-wave link in an active state as is.

[0112] On the other hand, if the RSSI of the wireless signal received by the wireless signal processing unit 152-3 from the terminal 20 is less than a predetermined value m at least x times within a predetermined time period (step S1005: No), the process proceeds to step S1007. In step S1007, the management unit 140 switches the millimeter-wave link from an active state to an inactive state. Afterward, the process returns to step S1001.

[0113] In this manner, the millimeter-wave link is set to either an active or inactive state based on its communication quality. When the millimeter-wave link is set to an inactive state, the management unit 140 maintains the inactive state if the communication quality is worse than a predetermined reference, and switches the millimeter-wave link from an inactive state to an active state if the communication quality is better than the predetermined reference. Conversely, when the millimeter-wave link is set to an active state, the management unit 140 maintains the active state if the communication quality is better than the predetermined reference, and switches the millimeter-wave link from an active state to an inactive state if the communication quality is worse than the predetermined reference.

[0114] In the examples described herein, the reference for switching the millimeter-wave link from an invalid state to an active state is the same as the reference for switching the millimeter-wave link from an active state to an invalid state. Alternatively, the reference for switching the millimeter-wave link from an invalid state to an active state may be different from the reference for switching the millimeter-wave link from an active state to an invalid state.

[0115] Figure 11 This diagram illustrates, in summary, an example of the process for switching a millimeter-wave link from an invalid to an active state. Furthermore, Figure 11 The processing shown can also be applied when the millimeter-wave link is set to an active state.

[0116] Figure 11 The diagram shows the management unit 140 and auxiliary APs 155-1 and 155-3 included in the AP-type MLD 190 of access point 10, and the auxiliary STAs 255-1 and 255-3 included in the non-AP-type MLD 290 of terminal 20; other components are omitted. Here, it is assumed that the wireless link established between the auxiliary AP 155-1 of access point 10 and the auxiliary STA 255-1 of terminal 20 is set as the primary link.

[0117] In step S1101, the auxiliary AP 155-1 sends a test frame transmission notification to the terminal 20. Specifically, the management unit 140 uses the auxiliary AP 155-1 to send the test frame transmission notification to the terminal 20. The test frame transmission notification is a MAC frame (e.g., a management frame) that includes information notifying the commencement of test frame transmission using the millimeter-wave link. The management unit 240 of the terminal 20 receives the test frame transmission notification from the access point 10 via the auxiliary STA 255-1.

[0118] In step S1102, the auxiliary STA 255-1 sends a test-enforceability notification to access point 10. Specifically, the management unit 240 sends the test-enforceability notification to access point 10 via the auxiliary STA 255-1. The test-enforceability notification is a MAC frame (e.g., a management frame) in response to the notification sent in response to the test frame. The management unit 140 of access point 10 receives the test-enforceability notification from terminal 20 via the auxiliary AP 155-1.

[0119] In step S1103, in response to receiving a test executability notification from terminal 20, management unit 140 instructs auxiliary AP 155-3 to send a test frame.

[0120] In step S1104, the auxiliary AP 155-3 receives an instruction from the management unit 140 and sends a test frame to the terminal 20 via the millimeter-wave link. In step S1105, when the management unit 240 of the terminal 20 successfully receives the test frame from the terminal 20, it uses the auxiliary STA 255-3 to send an Ack frame to the access point 10 via the millimeter-wave link; otherwise, it does not send an Ack frame.

[0121] The test frame transmission shown in step S1104 is repeated a predetermined number of times (a times).

[0122] In step S1106, the management unit 240 sends a test result report to the access point 10 using the auxiliary STA 255-1. The test result report is a MAC frame (e.g., a management frame) that includes information indicating the number of test frames successfully received. As an example, the management unit 140 of the access point 10 sends a test completion notification to the terminal 20 using the auxiliary AP 155-1 to notify the terminal 20 that test frame transmission has ended. In response to receiving the test completion notification from the access point 10, the management unit 140 of the terminal 20 sends a test result report to the access point 10.

[0123] The management unit 140 of access point 10 receives a test result report from terminal 20 via the auxiliary AP 155-1. For example, the management unit 240 determines whether to switch the millimeter-wave link to active status based on the number of times terminal 20 successfully received test frames, as indicated by the received test result report. Here, if the number of times terminal 20 successfully received test frames is above a predetermined value, the management unit 140 determines to switch the millimeter-wave link to active status.

[0124] In step S1107, the management unit 140 instructs the auxiliary AP 155-3 to use the millimeter-wave link. In step S1108, the management unit 140 uses the auxiliary AP 155-1 to send a millimeter-wave link usage notification to the terminal 20. The millimeter-wave link usage notification is a MAC frame (e.g., a management frame) that includes information notifying the use of the millimeter-wave link for data communication, specifically notifying the switching of the millimeter-wave link from an invalid state to an active state. The management unit 240 of the terminal 20 receives the millimeter-wave link usage notification from the access point 10 via the auxiliary STA 255-1 and notifies the auxiliary STA 255-3 to use the millimeter-wave link.

[0125] In this way, in response to the improved communication quality of the millimeter-wave link, the millimeter-wave link switches from an inactive state to an active state. In the example above, control information such as test frame transmission notifications, test implementability notifications, test result reports, or millimeter-wave link usage notifications are transmitted through the wireless link designated as the primary link.

[0126] Here, access point 10 evaluates the communication quality of the millimeter-wave link based on the test result report from terminal 20. Alternatively, it can refer to... Figure 10 The access point 10 evaluates the communication quality of the millimeter-wave link based on the number of times it fails to receive Ack frames from the terminal 20.

[0127] Figure 12 This diagram illustrates, in summary, an example of the process for switching a millimeter-wave link from an active to an inactive state. Furthermore, Figure 12 The processing shown can also be applied to situations where the millimeter-wave link is set to an invalid state.

[0128] Figure 12The diagram shows the management unit 140 and auxiliary APs 155-1 and 155-3 included in the AP-type MLD 190 of access point 10, and the auxiliary STAs 255-1 and 255-3 included in the non-AP-type MLD 290 of terminal 20; other components are omitted. Here, it is assumed that the wireless link established between the auxiliary AP 155-1 of access point 10 and the auxiliary STA 255-1 of terminal 20 is set as the primary link.

[0129] In step S1201, the auxiliary AP 155-3 sends a data frame to the terminal 20. The management unit 240 of the terminal 20 receives the data frame from the access point 10 via the auxiliary STA 255-3.

[0130] In step S1202, the auxiliary STA 255-3 sends an Ack frame for the data frame to the access point 10.

[0131] In step S1203, the auxiliary AP 155-3 receives the Ack frame from the terminal 20 and transmits a communication quality report indicating the received power (e.g., RSSI) of the Ack frame to the management unit 140.

[0132] In step S1204, the auxiliary STA 255-3 sends a data frame to access point 10.

[0133] In step S1205, the auxiliary AP 155-3 receives a data frame from the terminal 20 and transmits a communication quality report indicating the received power of the data frame to the management unit 140. In step S1206, the auxiliary AP 155-3 sends an Ack frame to the terminal 20 for the data frame from the terminal 20.

[0134] In step S1207, the auxiliary AP 155-3 sends a data frame to the terminal 20. In step S1208, the auxiliary STA 255-3 sends an Ack frame for the data frame to the access point 10. In step S1209, the auxiliary AP 155-3 receives the Ack frame from the terminal 20 and transmits a communication quality report indicating the received power of the Ack frame to the management unit 140.

[0135] After data exchange occurs between access point 10 and terminal 20 within a predetermined unit period, the management unit 140 of access point 10 determines whether to switch the millimeter-wave link to an invalid state based on the number of times the received power is below a predetermined value within the unit period. If the number of times the received power is below the predetermined value within the unit period exceeds a predetermined number, the management unit 140 determines to switch the millimeter-wave link to an invalid state; otherwise, it determines to maintain the millimeter-wave link in its valid state as is. Here, it is assumed that the management unit 140 determines to switch the millimeter-wave link to an invalid state.

[0136] In step S1210, the management unit 140 instructs the auxiliary AP 155-3 to stop using the millimeter-wave link. In step S1211, the management unit 140 uses the auxiliary AP 155-1 to send a millimeter-wave link usage stop notification to the terminal 20, notifying it to stop using the millimeter-wave link. The management unit 240 of the terminal 20 receives the millimeter-wave link usage stop notification from the access point 10 via the auxiliary STA 255-1 and notifies the auxiliary STA 255-1 to stop using the millimeter-wave link.

[0137] In this way, in response to the degradation of communication quality of millimeter-wave links, the use of millimeter-wave links is discontinued.

[0138] In the example above, an Ack frame is replied to for each data frame. Alternatively, a BlockAck frame, comprising multiple Ack frames for each of the multiple data frames, can also be replied to. BlockAck frames can be transmitted using a microwave band wireless link instead of a millimeter-wave link.

[0139] As described above, access point 10 includes wireless signal processing units 152-1 and 152-2 configured to transmit and receive wireless signals using the microwave band, and wireless signal processing unit 152-3 configured to transmit and receive wireless signals using the millimeter-wave band. Terminal 20 includes wireless signal processing units 252-1 and 252-2 configured to transmit and receive wireless signals using the microwave band, and wireless signal processing unit 252-3 configured to transmit and receive wireless signals using the millimeter-wave band. A first wireless link is established between wireless signal processing units 152-1 and 252-1, a second wireless link is established between wireless signal processing units 152-2 and 252-2, and a third wireless link is established between wireless signal processing units 152-3 and 252-3.

[0140] When the communication quality of the third wireless link becomes worse than a predetermined benchmark while the third wireless link is in a state used for data communication, access point 10 sends a first control message to terminal 20 to switch the third wireless link to a state not used for data communication. When the communication quality of the third wireless link becomes better than a predetermined benchmark while the third wireless link is in a state not used for data communication, access point 10 sends a second control message to terminal 20 to switch the third wireless link to a state used for data communication.

[0141] In the above structure, the use of the wireless link is controlled based on the communication quality of the wireless link using the millimeter-wave band. Specifically, when the communication quality of the wireless link deteriorates, its use is stopped; when the communication quality of the wireless link improves, its use is resumed. As a result, highly reliable data transmission is possible even when the communication quality of the wireless link using the millimeter-wave band frequency channel is reduced.

[0142] Access point 10 transmits first control information and second control information to terminal 20 via either the first or second wireless link. This architecture utilizes a more stable wireless link to transmit control information, achieving high reliability in its transmission.

[0143] Access point 10 receives an association request from terminal 20 via wireless signal processing unit 152-1 or wireless signal processing unit 152-2 to establish a link group including a first wireless link, a second wireless link, and a third wireless link, and establishes the link group in response to the association request. The association request includes calibration information for adjusting the wireless frequency of the interface using the millimeter-wave band. According to this structure, calibration information can be exchanged between access point 10 and terminal 20 before connection between access point 10 and terminal 20. In addition, control information required for calibration, such as calibration start and completion notifications, can be exchanged via the first wireless link.

[0144] The above implementation is an example. The following describes variations of the implementation.

[0145] In the above embodiment, one auxiliary AP 155 using the millimeter wave band is provided in access point 10. Multiple auxiliary APs 155 using the millimeter wave band can be provided in access point 10.

[0146] In the variant example, Figure 5 In the access point 10 shown, both the wireless signal processing unit 152-2 and the wireless signal processing unit 152-3 are configured to transmit and receive wireless signals using the millimeter wave band. The wireless signal processing unit 152-2 is used to monitor other channels included in the millimeter wave band. Other channels included in the millimeter wave band refer to channels different from those currently used by the wireless signal processing unit 152-3.

[0147] In a variation, when the communication quality of the millimeter-wave link deteriorates, instead of stopping the use of the millimeter-wave link, the channel is switched to continue data communication on the millimeter-wave link.

[0148] Figure 13 This illustration provides an example of the process for determining channel switching target candidates. Figure 13 The processing shown is performed by access point 10.

[0149] In step S1301, the management unit 140 selects one channel from the multiple channels included in the millimeter-wave band that is different from the channel being used by the wireless signal processing unit 152-3.

[0150] In step S1302, the management unit 140 applies the selected channel to the wireless signal processing unit 152-2 and monitors the communication status of data communication using the selected channel. The processing shown in steps S1303 and S1304 is similar to... Figure 10 The processes shown in steps S1004 and S1005 are the same. For example, the management unit 140 sends a test frames through the selected channel, counts the number of times the Ack frame reception fails, and thereby evaluates the communication status of the channel. Before sending the test frames, the same channel is synchronously set at the access point 10 and the terminal 20. For example, the access point 10 uses the wireless signal processing unit 152-1 to send the information of the channel selected in step S1301 to the terminal 20 through a wireless link in the microwave band.

[0151] If the data communication quality using the channel selected in step S1301 is worse than the predetermined benchmark (step S1303: Yes or step S1304: No), the process returns to step S1301. In step S1301, another channel is selected, and subsequent processing is performed.

[0152] If the data communication quality using the channel selected in step S1301 is better than the predetermined benchmark (step S1303: No and step S1304: Yes), the management unit 140 uses the channel selected in step S1301 as a candidate for handover (step S1305). Next, the process returns to step S1301. In step S1301, another channel is selected, and subsequent processing is performed.

[0153] In this way, channels in the millimeter-wave band with communication quality better than a predetermined benchmark are identified as candidates for handover targets.

[0154] Figure 14 This diagram illustrates an example of the processing involved in switching channels used in a millimeter-wave link. Figure 14 The processing shown is performed by access point 10.

[0155] In step S1401, the management unit 140 monitors the communication status of data communication using the millimeter-wave link. The processing shown in steps S1402 and S1403 is similar to... Figure 10 The processes shown in steps S1004 and S1005 are the same, so the description of these processes is omitted.

[0156] If the data communication quality using the millimeter-wave link is better than the predetermined benchmark (step S1402: No and step S1403: Yes), the process returns to step S1401. In this case, the channel is not switched.

[0157] If the data communication quality using the millimeter-wave link is worse than a predetermined reference (step S1402: Yes or step S1403: No), the process proceeds to step S1404. In step S1404, the management unit 140 switches the channel used in the millimeter-wave link. For example, the management unit 140 selects to use... Figure 13The process shown identifies one or more handover target candidates, and the selected candidate is applied to the millimeter-wave link. For example, the handover target candidate with the best communication quality is selected.

[0158] In addition, through Figure 13 When none of the switching target candidates shown are determined, the management unit 140 can switch the millimeter-wave link from an active state (a state used for data communication) to an inactive state (a state not used for data communication).

[0159] Management unit 140 uses auxiliary AP 155-1 to send a channel handover notification to terminal 20, including handover information indicating the channel of the millimeter-wave link being switched. The channel handover notification is a MAC frame (e.g., a management frame). The handover information is an example of control information, including information determining the channel after the switch. The handover information may include information indicating the timing of the channel switch. Alternatively, the handover timing can be predetermined so that the handover is performed after a predetermined time has elapsed since the channel handover notification was received. Management unit 140 of terminal 20 receives the channel handover notification from access point 10 and switches the millimeter-wave link channel to the channel specified in the handover notification.

[0160] In this way, the channel used in the millimeter-wave link is switched when the quality of data communication using the millimeter-wave link deteriorates. Therefore, highly reliable data transmission can still be achieved even when the communication quality of the wireless link using the millimeter-wave band frequency channel is reduced.

[0161] In the above embodiment, access point 10 determines whether to use the millimeter-wave link for data communication. Alternatively, terminal 20 may determine whether to use the millimeter-wave link for data communication. In this case, terminal 20 sends control information to access point 10 to switch whether to use the millimeter-wave link for data communication, and access point 10 responds to receiving the control information from terminal 20 by controlling the use of the millimeter-wave link.

[0162] Furthermore, the present invention is not limited to the embodiments described above, and various modifications can be made during implementation without departing from its spirit. Additionally, the embodiments can be combined as appropriate, resulting in combined effects. Moreover, the above embodiments include various inventions, which can be extracted by selecting combinations from a plurality of disclosed constituent elements. For example, if the technical problem can be solved and an effect obtained even if several constituent elements are deleted from all the constituent elements shown in the embodiments, the structure with the deleted constituent elements can also be extracted as an invention.

Claims

1. An access point, comprising: a first wireless signal processing section configured to transmit and receive wireless signals using a microwave band; a second wireless signal processing section configured to transmit and receive wireless signals using a millimeter wave band; and a management section that manages a first wireless link between the first wireless signal processing section and a wireless terminal device and a second wireless link between the second wireless signal processing section and the wireless terminal device, the management section: switches the second wireless link to a state not used for data communication in a case where a communication quality of the second wireless link becomes worse than a predetermined first reference while the second wireless link is in a state used for data communication, and switches the second wireless link to the state used for data communication in a case where the communication quality of the second wireless link becomes better than a predetermined second reference while the second wireless link is in the state not used for data communication.

2. The access point according to claim 1, wherein the management section exchanges control information for switching whether or not the second wireless link is used for the data communication with the wireless terminal device through the first wireless link.

3. The access point according to claim 1, wherein the management section: receives an association request requesting establishment of a link group including the first wireless link and the second wireless link from the wireless terminal device via the first wireless signal processing section, establishes the first wireless link and the second wireless link in response to the association request, and the association request includes calibration information for adjusting a wireless frequency of the millimeter wave band.

4. A wireless terminal device, comprising: a first wireless signal processing section configured to transmit and receive wireless signals using a microwave band; a second wireless signal processing section configured to transmit and receive wireless signals using a millimeter wave band; and a management section that manages a first wireless link between the first wireless signal processing section and an access point and a second wireless link between the second wireless signal processing section and the access point, the management section: switches the second wireless link to a state not used for data communication in a case where a communication quality of the second wireless link becomes worse than a predetermined first reference while the second wireless link is in a state used for data communication, and switches the second wireless link to the state used for data communication in a case where the communication quality of the second wireless link becomes better than a predetermined second reference while the second wireless link is in the state not used for data communication. wherein 5. The wireless terminal device according to claim 4, wherein the management section exchanges control information for switching whether or not the second wireless link is used for the data communication with the access point through the first wireless link.

6. The wireless terminal device according to claim 4, wherein the management section transmits an association request requesting establishment of a link group including the first wireless link and the second wireless link to the access point using the first wireless signal processing section, and the association request includes calibration information for adjusting a wireless frequency of the millimeter wave band. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ wherein ​ ​ ​ ​ ​ ​ ​ ​ 7. A wireless communication method executed by an access point, the access point being provided with a first wireless signal processing section configured to transmit and receive a wireless signal using a microwave band, and a second wireless signal processing section configured to transmit and receive a wireless signal using a millimeter wave band, the wireless communication method comprising: managing a first wireless link between the first wireless signal processing section and a wireless terminal device, and a second wireless link between the second wireless signal processing section and the wireless terminal device, switching the second wireless link to a state not used for data communication, in a case where a communication quality of the second wireless link becomes worse than a predetermined first reference while the second wireless link is in a state used for data communication, and switching the second wireless link to the state used for data communication, in a case where the communication quality of the second wireless link becomes better than a predetermined second reference while the second wireless link is in the state not used for data communication.

8. A wireless communication method executed by a wireless terminal device, the wireless terminal device being provided with a first wireless signal processing section configured to transmit and receive a wireless signal using a microwave band, and a second wireless signal processing section configured to transmit and receive a wireless signal using a millimeter wave band, the wireless communication method comprising: managing a first wireless link between the first wireless signal processing section and an access point, and a second wireless link between the second wireless signal processing section and the access point, switching the second wireless link to a state not used for data communication, in a case where a communication quality of the second wireless link becomes worse than a predetermined first reference while the second wireless link is in a state used for data communication, and switching the second wireless link to the state used for data communication, in a case where the communication quality of the second wireless link becomes better than a predetermined second reference while the second wireless link is in the state not used for data communication.

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