Shared access point, terminal and shared access point

Abstract

In a shared access point according to an embodiment, a management unit sets one of a plurality of links as an anchor link in response to receiving, from a terminal, a handover request for one or more of the plurality of links from the terminal to request switching to a connection target shared access point. The management unit switches the connection target shared access point to a link to be switched among links other than the anchor point link while maintaining a wireless connection with the connection target shared access point to the anchor point link.

Description

Technical Field

[0001] The implementation methods involve a sharing access point, a terminal, and a shared access point. Background Technology

[0002] As a system that wirelessly connects an access point (AP) to a terminal, a wireless LAN (Local Area Network) is known. In a wireless LAN, a terminal performs association processing with an AP in order to wirelessly connect to an AP. When a terminal switches its connection target from one AP to another due to movement, the wireless connection with the existing AP is severed, and an association process is then performed with the new target AP.

[0003] Furthermore, in IEEE 802.11be, which is being developed as a successor to IEEE 802.11ax, terminals are capable of establishing multiple links with an access point (AP) and transmitting and receiving data between the terminal and the AP via these multiple links. In multi-link communication, when switching the target AP for a wireless connection, the wireless connections with the APs in the current wireless connection are simultaneously disconnected on multiple links, and the multiple links are then centrally connected to the new target AP.

[0004] In communication systems where terminals perform multi-link communication, during handover operations (handover) for one or more target APs across multiple links, it is essential to effectively prevent momentary interruptions that could cause the wireless connection to be severed on all links. In other words, during the handover process, the target AP must be appropriately switched among the multiple links without causing momentary interruptions.

[0005] Existing technical documents

[0006] Non-patent literature

[0007] Non-patent literature 1: IEEE 802.11be D3.0, “35.3 Multi-link operation”, pp. 479-586, January 2023 Summary of the Invention

[0008] The technical problem that the invention aims to solve

[0009] The purpose of this invention is to provide a shared access point, terminal, and shared access point that can properly switch the target access point among multiple links from a terminal without causing momentary interruptions.

[0010] Technical solutions for solving technical problems

[0011] In one embodiment of the present invention, the shared access point includes a management unit. When multiple links from a terminal are wirelessly connected to one of multiple shared access points, the management unit, in response to receiving a handover request from the terminal requesting a switchover of one or more links to a target shared access point, designates one of the multiple links as an anchor link. While maintaining a wireless connection between the anchor link and the target shared access point, the management unit switches the connection to the target shared access point for the switching target link among the links other than the anchor link.

[0012] Invention Effects

[0013] According to the present invention, it is possible to provide a shared access point, a terminal, and a shared access point that appropriately switch the connection to the target access point among multiple links from a terminal without causing momentary interruptions. Attached Figure Description

[0014] Figure 1 This is a block diagram illustrating an example of the structure of a communication system according to an embodiment.

[0015] Figure 2 This is a block diagram illustrating an example of the hardware structure of a shared AP in an implementation.

[0016] Figure 3 This is a block diagram illustrating an example of the hardware structure of a shared AP in an implementation.

[0017] Figure 4 This is a block diagram illustrating an example of the hardware structure of a terminal according to an implementation method.

[0018] Figure 5 This is a block diagram illustrating an example of the functional structure of a shared AP in an implementation.

[0019] Figure 6 This is a block diagram illustrating an example of the functional structure of a shared AP in an implementation.

[0020] Figure 7 This is a block diagram illustrating an example of the functional structure of a terminal according to an implementation method.

[0021] Figure 8 This is a flowchart illustrating an example of the processing in a handover operation performed by a communication system according to an embodiment.

[0022] Figure 9 This is a schematic diagram illustrating an example of a handover operation in a communication system according to an embodiment.

[0023] Figure 10 This is a sequence diagram illustrating an example of communication processing based on a multi-AP connection method during the handover of work in the communication system of the embodiment.

[0024] Figure Labels

[0025] 1: Communication system; 10: Shared AP; 11, 21, 31: CPU; 12, 22, 32: ROM; 13, 23, 33: RAM; 14, 24, 34: Wireless communication module; 15: Wired communication module; 20, 20-1, 20-2, 20-3, 20-4: Shared AP; 30: Terminal; 35: Display; 36: Storage; 40: Network; 110, 310: LLC processing unit; 120: Data Processing Department; 130, 210, 330: Management Department; 131: Multi-AP Management Information; 132: Terminal Management Information; 133: Quality Estimation Department; 140: Frame Processing Department; 150, 230: Transceiver Department; 211, 331: Link Management Information; 220, 340: MAC Frame Processing Department; 240, 250, 350, 360: Wireless Signal Processing Department; 300: Application Execution Department; 370, 380: Quality Measurement Department. Detailed Implementation

[0026] The embodiments will now be described with reference to the accompanying drawings. Furthermore, in the following description, components having the same function and structure will be given common reference numerals.

[0027] Figure 1 This is a block diagram illustrating an example of the structure of a communication system according to an embodiment. (e.g.) Figure 1 As shown, the communication system 1 includes a sharing AP (access point) 10, shared APs 20-1, 20-2, and 20-3, and a terminal 30. The shared AP 10 is connected to the network 40.

[0028] Shared AP 10 is, for example, an access point (AP) for a wireless LAN. Shared AP 10 is configured to communicate wirelessly or wirelessly with a server (not shown) on network 40. Shared AP 10 is configured to communicate wirelessly or wiredly with each of the shared APs 20-1, 20-2, and 20-3.

[0029] Shared APs 20-1 to 20-3 are, for example, access points (APs) for a wireless LAN. Shared APs 20-1 to 20-3 are physically separated and have distinct communication areas. However, a portion of the communication area of ​​each shared AP 20-1 to 20-3 may overlap with the communication areas of other shared APs. Shared APs 20-1 to 20-3 are configured to wirelessly communicate with terminal 30. Communication between each shared AP 20-1 to 20-3 and terminal 30 conforms to, for example, the IEEE 802.11 standard. Furthermore, shared APs 20-1 to 20-3 have identical structures. Hereinafter, unless otherwise specified, shared APs 20-1 to 20-3 will sometimes be referred to as shared AP 20.

[0030] In addition, each of the shared APs 20 includes multiple affiliated APs. Figure 1 In the example, each shared AP20 has two auxiliary APs (A-APs). Therefore, shared AP 20-1 has A-AP 1-1 and A-AP 1-2, shared AP 20-2 has A-AP 2-1 and A-AP 2-2, and shared AP 20-3 has A-AP 3-1 and A-AP 3-2.

[0031] Terminal 30 is, for example, a wireless terminal such as a smartphone or PC (Personal Computer). Figure 1 In the example, terminal 30 is located within the communication area of ​​shared APs 20-1 and 20-2, but not within the communication area of ​​shared AP 20-3. Terminal 30 is configured to communicate with shared AP 10 via at least one of the shared APs 20-1 to 20-3, thereby communicating with the server on network 40. That is, terminal 30 is connected to shared AP 10 via at least one of the shared APs 20-1 to 20-3. The connection method between terminal 30 and shared AP 10 as described above is also called "multi-AP connection method".

[0032] Furthermore, terminal 30 is a wireless terminal that utilizes multiple channels (links) to implement wireless communication. Terminal 30 includes a non-AP type MLD and multiple affiliated STAs (stations). Figure 1In the example, terminal 30 includes A-STA1 and A-STA2 as subordinate STAs. The non-AP type MLD is the MLD (multi-link device) on the terminal 30 side that manages the link status from its subordinate STAs, namely each A-STA1 and A-STA2. The non-AP type MLD also implements processing for establishing the connection between the shared AP 10 and terminal 30 in a multi-AP connection mode.

[0033] In a multi-AP connection mode, connections (transmission paths) can be established between the AP-type MLD of shared AP 10 and the non-AP-type MLD of terminal 30 via shared AP 20-1, shared AP 20-2, and shared AP 20-3, respectively. That is, shared APs 20-1 to 20-3 serve as candidate transit points for data exchange between shared AP 10 and terminal 30. Furthermore, terminal 30's A-STA1 and A-STA2 perform data exchange with shared AP 10 via one of the candidate transit points, shared APs 20-1 to 20-3.

[0034] exist Figure 1 In the example, during data exchange between shared AP 10 and the non-AP type MLD of terminal 30, the links established between A-STA1 and shared AP 20-1, and between A-STA2 and shared AP 20-2, are used. Furthermore, in the following description, shared APs 20-1 to 20-3 are also referred to as access points "home" to shared AP 10 in the multi-AP connection mode.

[0035] Furthermore, in the multiple shared APs 20, each of the multiple auxiliary APs can only wirelessly connect to one of the multiple links (wireless links) from the terminal 30. Figure 1 In the example, the link from A-STA1 is wirelessly connected to A-AP 1-1 of shared AP 20-1, and the link from A-STA2 is wirelessly connected to A-AP 2-2 of shared AP 20-2. Since multiple auxiliary APs are configured in each shared AP 20, it is possible to wirelessly connect two or more links from multiple links from terminal 30 to one shared AP. For example, by wirelessly connecting the link from A-STA1 to A-AP 1-1 and the link from A-STA2 to A-AP 1-2, two links from terminal 30 are wirelessly connected to one shared AP 20-1.

[0036] Shared AP 10, shared APs 20-1 to 20-3, and terminal 30, for example, have wireless communication capabilities based on the OSI (Open Systems Interconnection) reference model. In the OSI reference model, wireless communication capabilities 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 the LLC (Logical Link Control) sublayer and the MAC (Media Access Control) sublayer.

[0037] Figure 2 This is a block diagram illustrating an example of the hardware structure of a shared AP in an implementation. Figure 2 The image shows an example of wireless communication between the shared AP10 and each of the shared AP20. For example... Figure 2 As shown, the shared AP 10 includes, for example, a CPU (Central Processing Unit) 11, a ROM (Read Only Memory) 12, a RAM (Random Access Memory) 13, a wireless communication module 14, and a wired communication module 15.

[0038] CPU 11 is a processing circuit that controls the overall operation of the shared AP 10. ROM 12 is, for example, a non-volatile semiconductor memory. ROM 12 stores programs and data used to control the shared AP 10. RAM 13 is, for example, a volatile semiconductor memory. RAM 13 serves as the working area of ​​CPU 11. Wireless communication module 14 is a circuit used for transmitting and receiving data using wireless signals. Wireless communication module 14 is connected to an antenna. Wired communication module 15 is a circuit used for transmitting and receiving data using wired signals. Wireless communication module 14 can be connected (wirelessly connected) to shared APs 20-1 to 20-3. Wired communication module 15 can be connected to network 40.

[0039] Furthermore, when the shared AP 10 communicates with each of the shared APs 20 via wired connections, the shared AP 10 does not include a wireless communication module 14. In this case, the wired communication module 15 can be connected to the network 40 and can be connected (wired) to the shared APs 20-1 to 20-3.

[0040] Figure 3 This is a block diagram illustrating an example of the hardware structure of a shared AP in an implementation. Figure 3 An example of wireless communication between shared AP 20 and shared AP 10 is shown. (e.g.) Figure 3As shown, the shared AP 20 includes, for example, a CPU 21, ROM 22, RAM 23 and a wireless communication module 24.

[0041] CPU 21 is a processing circuit that controls the overall operation of the shared AP 20. ROM 22 is, for example, a non-volatile semiconductor memory. ROM 22 stores programs and data used to control the shared AP 20. RAM 23 is, for example, a volatile semiconductor memory. RAM 23 serves as the working area of ​​CPU 21. Wireless communication module 24 is a circuit used for transmitting and receiving data using wireless signals. Wireless communication module 24 is connected to an antenna. Wireless communication module 24 can be connected (wirelessly connected) to shared AP 10 and terminal 30.

[0042] Furthermore, when the shared AP 20 communicates with the shared AP 10 via wired connection, the shared AP also includes a wired communication module (not shown). In this case, the wireless communication module 24 can be connected to the terminal 30, and the wired communication module can be connected (wired connection) to the shared AP 10.

[0043] Figure 4 This is a block diagram illustrating an example of the hardware structure of a terminal according to an implementation method. For example... Figure 4 As shown, terminal 30 includes, for example, a CPU 31, ROM 32, RAM 33, wireless communication module 34, display 35, and storage 36.

[0044] The CPU 31 is the processing circuitry for controlling the overall operation of the terminal 30. The ROM 32 is, for example, a non-volatile semiconductor memory. The ROM 32 stores programs and data used to control the terminal 30. The RAM 33 is, for example, a volatile semiconductor memory. The RAM 33 serves as the working area for the CPU 31. The wireless communication module 34 is the circuitry used for transmitting and receiving data using wireless signals. The wireless communication module 34 is connected to an antenna. The display 35 is, for example, an LCD (Liquid Crystal Display) or an EL (Electro-Luminescence) display. The display 35 displays a GUI (Graphical User Interface) or similar interface corresponding to the application software. The storage device 36 is a non-volatile storage device. The storage device 36 stores the system software of the terminal 30, etc.

[0045] Figure 5 This is a block diagram illustrating an example of the functional structure of a shared AP in an implementation. (e.g.) Figure 5As shown, the shared AP 10 functions as a computer equipped with an LLC processing unit 110, a data processing unit 120, a management unit 130, a frame processing unit 140, and a transceiver unit 150. The LLC processing unit 110 is a functional block that performs processing corresponding to the LLC sublayer of Layer 2 and Layers 3 to 7. The data processing unit 120, management unit 130, and frame processing unit 140 are functional blocks that perform processing corresponding to the MAC sublayer of Layer 2. Furthermore, when the shared AP 10 communicates wirelessly with each of the shared APs 20, the transceiver unit 150 is a functional block that performs processing corresponding to Layer 1.

[0046] LLC processing unit 110, for example, appends a DSAP (Destination Service Access Point) header or SSAP (Source Service Access Point) header to the data received from network 40 to generate LLC data packets. Then, LLC processing unit 110 inputs the generated LLC data packets to data processing unit 120. Additionally, LLC processing unit 110 extracts data from the LLC data packets input from data processing unit 120. Then, LLC processing unit 110 sends the extracted data to network 40.

[0047] The data processing unit 120 outputs LLC data packets input from the LLC processing unit 110 to the frame processing unit 140. Additionally, the data processing unit 120 outputs LLC data packets input from the frame processing unit 140 to the LLC processing unit 110.

[0048] The management unit 130 controls the establishment of a logical wireless connection between the shared AP 10 and the non-AP type MLD of the terminal 30 in a multi-AP connection mode. In the multi-AP connection mode, data exchange occurs between the shared AP 10 and the terminal 30 when the links (wireless links) from the auxiliary STAs of the terminal 30, i.e., each A-STA1 and A-STA2, are wirelessly connected to any one of the shared APs 20-1 to 20-3. The management unit 130 controls the establishment of wireless connections with the target shared AP 20 for each of the multiple links from the terminal 30, i.e., the links from each A-STA1 and A-STA2.

[0049] Furthermore, in a multi-AP connection mode, when terminal 30 moves from the communication area of ​​one shared AP 20 to the communication area of ​​another shared AP 20, a handover operation is performed to switch the target shared AP 20 for one or more links from multiple links originating from terminal 30. During the handover operation, the management unit 130 controls the switching of the shared AP 20 as the wireless connection target for each switching target link. During the handover operation, for each switching target link, the wireless connection with the shared AP 20 in the wireless connection is disconnected in real time, and a wireless connection is established with the shared AP 20 as the new connection target.

[0050] During the handover process, the management unit 130 controls the switching of the connection targets for each link being switched, without any momentary interruption that would result in the loss of wireless connections to the shared AP 20 on all multiple links from the terminal 30. Furthermore, in the following description, the process of establishing a wireless connection with one of the shared AP 20 for each of the multiple links from the terminal 30 is also referred to as "association processing," and the process of severing the wireless connection with the shared AP 20 is also referred to as "deassociation processing."

[0051] Additionally, the management unit 130 stores multi-AP management information 131 and terminal management information 132. The multi-AP management information 131 includes information about the access points used in the multi-AP connection method (i.e., shared AP 10 and shared APs 20-1 to 20-3). Information about the access points used in the multi-AP connection method includes, for example, identifiers, frequency bands, and operating parameters. Furthermore, the information about shared AP 20 may include information about each of the multiple affiliated APs installed on shared AP 20. In this case, the identifiers, frequency bands, and operating parameters of each of the multiple affiliated APs installed on shared AP 20 are included in the multi-AP management information 131.

[0052] The identifier is, for example, the identifier of the corresponding AP. The identifier may include the MAC address of the corresponding AP. The frequency band includes information indicating the frequency band used by the corresponding AP in a multi-AP connection mode. As a frequency band, for example, the 2.4GHz band, 5GHz band, 6GHz band, 45GHz band, and 60GHz band may be applied. Each frequency band may contain multiple channels. In this case, the multi-AP management information 131 may include channel information instead of frequency band information, or may include channel information in addition to frequency band information.

[0053] Operating parameters include, for example, CWmin, CWmax, AIFS (arbitration interframe space), and TXOP (transmission opportunity) Limit. CWmin and CWmax represent the minimum and maximum values ​​of the contention window, respectively. The contention window is a parameter used to calculate backoff, i.e., the transmission waiting time used to avoid collisions. AIFS is a fixed transmission waiting time set for each access class of traffic. Access classes include, for example, "VO (voice)," "VI (video)," "BE (best-effort service)," "BK (background)," and "LL (low-latency)." TXOPLimit represents the upper limit of the channel occupancy period (TXOP).

[0054] Terminal management information 132 stores information about terminal 30 connected to shared AP 10 in a multi-AP connection mode. Specifically, terminal management information 132 includes the identifier of the non-AP type MLD of terminal 30 and the identifiers of the affiliated STAs and shared AP 20 traversed in the connection with terminal 30. The identifier of the non-AP type MLD of terminal 30 may include the MAC address of the non-AP type MLD. In addition, the identifier of the affiliated STA traversed in the connection with terminal 30 may include the MAC address of the affiliated STA, and the identifier of the shared AP 20 traversed in the connection with terminal 30 may include the MAC address of the shared AP 20.

[0055] Additionally, the terminal management information 132 may include the identifier of the affiliated AP traversed in the connection with terminal 30 as information about the shared AP 20 traversed in the connection with terminal 30. The identifier of the affiliated AP traversed in the connection with terminal 30 may include the MAC address of the affiliated AP.

[0056] Data from the data processing unit 120 is input to the frame processing unit 140 as LLC data packets. When the shared AP 10 is communicating wirelessly with each of the shared APs 20, the frame processing unit 140 appends a MAC header to the LLC data packets input from the LLC processing unit 110 to generate a MAC frame. Then, the frame processing unit 140 outputs the generated MAC frame to the transceiver unit 150. Additionally, when the shared AP 10 is communicating wirelessly with each of the shared APs 20, the frame processing unit 140 extracts LLC data packets from the MAC frames input from the transceiver unit 150. Then, the frame processing unit 140 outputs the extracted LLC data packets to the data processing unit 120. Furthermore, in the following description, the MAC frame containing data is also referred to as a "data frame".

[0057] When the shared AP 10 communicates with each of the shared APs 20 via wired connections, the frame processing unit 140 outputs LLC data packets input from the data processing unit 120 to the transceiver unit 150. Additionally, the frame processing unit 140 outputs LLC data packets input from the transceiver unit 150 to the data processing unit 120.

[0058] Additionally, management information is input from the management unit 130 to the frame processing unit 140, and the frame processing unit 140 outputs the management information from the management unit 130 to the transceiver unit 150. The management information includes notification information to any of the shared APs 20 and terminals 30, as well as control information related to the operation of any of the shared APs 20 and terminals 30. Furthermore, control information related to the operation of auxiliary APs in each of the shared APs 20 may also be included in the management information. Additionally, the management information may include the aforementioned multi-AP management information 131 and terminal management information 132. When the shared AP 10 communicates wirelessly with each of the shared APs 20, the frame processing unit 140 generates a MAC frame, i.e., a management frame, containing the management information from the management unit 130, and outputs the generated management frame to the transceiver unit 150.

[0059] Additionally, data and management information are input from the transceiver unit 150 to the frame processing unit 140. The management information input from the transceiver unit 150 includes notification information from either the shared AP 20 or the terminal 30. When data is input from the transceiver unit 150 as a data frame or LLC data packet, the frame processing unit 140 outputs the input data to the data processing unit 120. Similarly, when management information is input from the transceiver unit 150, the frame processing unit 140 outputs the input notification information to the management unit 130. During wireless communication between the shared AP 10 and each of the shared APs 20, MAC frames containing management information, i.e., management frames, are input from the transceiver unit 150 to the frame processing unit 140, and the frame processing unit 140 outputs the management information contained in the management frames from the transceiver unit 150 to the management unit 130.

[0060] The transceiver unit 150 transmits and receives data and management information with each of its assigned shared APs 20 via wireless or wired communication. When the shared AP 10 communicates wirelessly with each of the shared APs 20, the transceiver unit 150 includes one or more wireless signal processing units. Each wireless signal processing unit of the transceiver unit 150 then adds a preamble or similar code to the MAC frame (data frame, management frame, etc.) input from the frame processing unit 140 to generate a wireless frame, and converts the generated wireless frame into a wireless signal. Each wireless signal processing unit then transmits (radiates) the converted wireless signal via an antenna. The conversion processing from wireless frame to wireless signal includes, for example, convolutional coding, interleaving, subcarrier modulation, inverse fast Fourier transform, OFDM modulation, and frequency conversion.

[0061] Furthermore, each wireless signal processing unit of the transceiver unit 150 converts the wireless signals received from any shared AP 20 via the antenna into wireless frames. The conversion process from wireless signals to wireless frames includes, for example, frequency conversion, OFDM demodulation, fast Fourier transform, subcarrier demodulation, deinterleaving, and Viterbi decoding. Each wireless signal processing unit extracts a MAC frame from the converted wireless frame and outputs the extracted MAC frame to the frame processing unit 140.

[0062] In one example, each of the three shared APs 20-1 to 20-3 is provided with one wireless signal processing unit in the transceiver unit 150. Then, the frame processing unit 140 inputs data to be sent to shared AP 20-1 to the wireless signal processing unit corresponding to shared AP 20-1, data to be sent to shared AP 20-2 to the wireless signal processing unit corresponding to shared AP 20-2, and data to be sent to shared AP 20-3 to the wireless signal processing unit corresponding to shared AP 20-3. In another example, each of the three shared APs 20-1 to 20-3 is provided with one wireless signal processing unit in the transceiver unit 150, and a wireless signal processing unit for sending management information to the multiple shared APs 20 is provided separately from these three wireless signal processing units. Furthermore, when multiple wireless signal processing units are provided in the transceiver unit 150 as in the previous example, these multiple wireless signal processing units are configured to transmit and receive wireless signals using different frequency bands or channels.

[0063] When the shared AP 10 communicates with each of the shared APs 20 via wired connections, the transceiver unit 150 is connected to each of the assigned shared APs 20-1 to 20-3 via a wired network, and sends and receives data and management information between the shared APs 20-1 to 20-3 via the wired network. In this case, the transceiver unit 150 is composed of a network interface of the wired network.

[0064] The management unit 130 collaborates with the non-AP type MLDs of the home shared AP 20 and terminal 30 to allocate (map) traffic transmitted and received between the shared AP 10 and terminal 30. Accordingly, traffic such as data sent from the shared AP 10 is allocated to the home shared APs 20-1 to 20-3 and to multiple links from terminal 30. Based on the traffic allocation results, the management unit 130 instructs the frame processing unit 140 on the destination of the traffic. Then, the frame processing unit 140 sends the traffic from the transceiver unit 150 to the shared AP 20 corresponding to the instruction from the management unit 130. For example, based on the instruction from the management unit 130, traffic allocated to a link with shared AP 20-1 as the connection target is sent from the transceiver unit 150 of the shared AP 10 to shared AP 20-1. Furthermore, the management unit 130 can allocate traffic based on a TID (traffic identifier) ​​corresponding to the access class.

[0065] Additionally, the management unit 130 includes a quality estimation unit 133. A quality measurement unit is provided in the terminal 30 or each shared AP 20 to measure the communication quality of each of the multiple links (wireless links) from the terminal 30. In the shared AP 10, the transceiver unit 150 receives the measurement results regarding the communication quality of each of the multiple links, and the frame processing unit 140 outputs the measurement results received by the transceiver unit 150 to the quality estimation unit 133 of the management unit 130. Then, the quality estimation unit 133 estimates the quality of each of the multiple links from the terminal 30 based on the measurement results of the quality measurement unit. In one example, the received power in the reception of the wireless signal is measured for each of the multiple links. Then, the quality estimation unit 133 estimates the quality of each of the multiple links based on the change in received power over time.

[0066] In communication system 1, a handover request is sent from terminal 30, requesting a switchover of connection target shared AP 20 for one or more of the multiple links from terminal 30. The transceiver unit 150 of shared AP 10 receives the handover request sent via any shared AP 20. In response to receiving the handover request from terminal 30, management unit 130 causes the home shared AP 20 and terminal 30 to perform handover operations. During the handover operation, management unit 130 sends management information used in controlling the handover operation from transceiver unit 150 to the home shared AP 20. Furthermore, management unit 130 manages the start and end of the handover operation.

[0067] Based on the received handover request, the management unit 130 designates a handover target link from among multiple links from the terminal 30 as the target for the handover connection. At this time, for example, a link whose communication quality, as estimated by the quality estimation unit 133, has decreased below a baseline level is designated as a handover target link. In one example, a link with received power below a threshold is designated as a handover target link. During the handover process, depending on the situation, sometimes only a portion of the multiple links are designated as handover target links, and sometimes all of the multiple links are designated as handover target links.

[0068] Additionally, in response to receiving a handover request from terminal 30, management unit 130 designates one of the multiple links from terminal 30 as the handover anchor link. In the following explanation, the handover anchor link is simply referred to as the "anchor link." For example, the link with the most stable estimated communication quality among the multiple links is designated as the anchor link. In one example, the link with the most stable received power is designated as the anchor link. In this case, for each of the multiple links, the higher the received power value, the higher the stability of the received power is considered; the less the received power changes over time, the higher the stability of the received power is considered. The anchor link can be designated from the handover target links or from links other than the handover target links. However, when only a portion of the multiple links are designated as handover target links, it is preferable to prioritize designating the anchor link from links other than the handover target links. Furthermore, the links designated as anchor links can be changed sequentially during the handover process. In one example, after the target of the connection has been switched for a link other than the anchor link, the anchor link is changed to the corresponding link among the links for which the target of the connection has been switched.

[0069] The management unit 130 sends the anchor link configuration information from the transceiver unit 150 to the home shared AP 20. Then, the management unit 130 controls the handover process between the shared AP 20 and the terminal 30 based on the anchor link configuration information. At this time, while maintaining a wireless connection with the target shared AP 20 via the anchor link, the management unit 130 switches the target shared AP 20 for handover links other than the anchor link. Furthermore, when the anchor link is a handover target link, the management unit 130 switches the target shared AP 20 for the anchor link based on the assumption that the handover of the target shared AP 20 has been completed for all handover target links other than the anchor link.

[0070] The management unit 130 of the shared AP 10 manages the start and end of the handover process for each handover target link to the shared AP 20. The management unit 130 receives a notification from the corresponding shared AP 20 indicating that the deassociation process is complete. In this deassociation process, the wireless connection with the shared AP 20 is severed for each handover target link. Additionally, the management unit 130 receives a notification from the corresponding shared AP 20 indicating that the association process is complete. In this association process, a wireless connection is established between each handover target link and the shared AP 20, which is the new connection target.

[0071] Based on the fact that notifications of deassociation completion and association completion have been received for each handover target link, the management unit 130 determines that the connection target handover operation has been completed. Furthermore, when the anchor link is the handover target, based on the fact that notifications of deassociation completion and association completion have been received for all handover target links other than the anchor link, the management unit 130 initiates the handover operation for the anchor link's shared AP20.

[0072] Additionally, in response to the establishment of the anchor link, during the handover of the connection target shared AP 20 to a handover target link other than the anchor link, the management unit 130 allocates (maps) the traffic transmitted and received between the anchor link and the terminal 30 via the shared AP 20. Therefore, during the handover of the connection target to a handover target link other than the anchor link, traffic is allocated to the shared AP 20 wirelessly connected to the anchor link.

[0073] Furthermore, during the connection target switching operation for the anchor link, the management unit 130 allocates traffic to and from the terminal 30 based on the links other than the anchor link among the multiple links. Therefore, during the connection target switching operation for the anchor link, traffic is not allocated to the anchor link. Additionally, when the connection target switching and handover operation for the anchor link is completed, the management unit 130 allocates traffic to and from the terminal 30 based on all multiple links, including the anchor link.

[0074] Figure 6This is a block diagram illustrating an example of the functional structure of a shared AP according to an embodiment. The shared AP 20 functions as a computer including a management unit 210, a MAC frame processing unit 220, a transceiver unit 230, and wireless signal processing units 240 and 250. The management unit 210 and the MAC frame processing unit 220 are functional blocks that perform processing corresponding to the MAC sublayer of Layer 2. The wireless signal processing units 240 and 250 are functional blocks that perform processing corresponding to Layer 1. Furthermore, when the shared AP 10 communicates wirelessly with each of the shared APs 20, the transceiver unit 230 performs processing corresponding to Layer 1; when the shared AP 10 communicates wiredly with each of the shared APs 20, the transceiver unit 230 performs processing corresponding to the MAC sublayer of Layer 2.

[0075] The transceiver unit 230 transmits and receives data and management information with the shared AP 10 via wireless or wired communication. When the shared AP 20 communicates wirelessly with the shared AP 10, the transceiver unit 230 includes a wireless signal processing unit. Furthermore, the wireless signal processing unit of the transceiver unit 230 adds preambles or the like to MAC frames (data frames, management frames, etc.) input from the MAC frame processing unit 220 to generate wireless frames. Then, the wireless signal processing unit of the transceiver unit 230 converts the generated wireless frames into wireless signals and transmits (radiates) the converted wireless signals to the shared AP 10 via an antenna. The conversion processing from wireless frames to wireless signals is performed in the manner described above.

[0076] Furthermore, the wireless signal processing unit of transceiver unit 230 converts the wireless signal received from shared AP 10 via the antenna into wireless frames. The conversion process from wireless signal to wireless frame is performed as described above. The wireless signal processing unit extracts the MAC frame from the converted wireless frame and outputs the extracted MAC frame to MAC frame processing unit 220.

[0077] When the shared AP 20 communicates with the shared AP 10 via a wired connection, the transceiver unit 230 is connected to the shared AP 10 via a wired network, and sends and receives data and management information with the shared AP 10 via the wired network. In this case, the transceiver unit 230 is composed of a network interface of the wired network.

[0078] When the shared AP 20 and the shared AP 10 communicate via wired connection, the MAC frame processing unit 220 generates a MAC frame containing data or management information received from the shared AP 10 by the transceiver unit 230. For example, the MAC frame processing unit 220 appends a MAC header to an LLC data packet received from the shared AP 10 by the transceiver unit 230 to generate a MAC frame (data frame). Furthermore, when the shared AP 20 and the shared AP 10 communicate via wired connection, and a data frame is input as a MAC frame from either the wireless signal processing units 240 or 250, the MAC frame processing unit 220 extracts LLC data packets from the input data frame and outputs the extracted LLC data packets to the transceiver unit 230. Additionally, the MAC frame processing unit 220 outputs management information from the management unit 210 to the transceiver unit 230. Then, the transceiver unit 230 sends LLC data packets and management information to the shared AP 10 via wired communication.

[0079] Wireless signal processing units 240 and 250 are capable of transmitting and receiving data and management information with terminal 30 via wireless communication. Therefore, wireless signal processing units 240 and 250 sharing AP 20 can establish a wireless connection with terminal 30 via any one or more links from terminal 30, i.e., via any one or more links from each STA1 and STA2. Wireless signal processing units 240 and 250 add preambles or similar parameters to MAC frames (data frames, management frames, etc.) input from MAC frame processing unit 220 to generate wireless frames. Then, wireless signal processing units 240 and 250 convert the generated wireless frames into wireless signals and transmit (radiate) the converted wireless signals to terminal 30 via antennas. The conversion process from wireless frames to wireless signals is performed as described above.

[0080] Furthermore, wireless signal processing units 240 and 250 convert the wireless signals received from terminal 30 via antenna into wireless frames. The conversion process from wireless signals to wireless frames is performed as described above. Wireless signal processing units 240 and 250 extract MAC frames from the converted wireless frames and output the extracted MAC frames to MAC frame processing unit 220.

[0081] Furthermore, in the shared AP 20, multiple wireless signal processing units 240 and 250 are configured to transmit and receive wireless signals using different frequency bands or channels. Additionally, when the shared AP 20 communicates wirelessly with the shared AP 10, it is preferable that the wireless signal processing unit of the transceiver unit 230 uses a different frequency band or channel than the wireless signal processing units 240 and 250. In one example, the wireless signal processing unit 240 is configured to transmit and receive wireless signals using the same frequency band or channel as STA1 of the terminal 30, and the wireless signal processing unit 250 is configured to transmit and receive wireless signals using the same frequency band or channel as STA2 of the terminal 30. Then, the wireless signal processing unit of the transceiver unit 230 is configured to transmit and receive wireless signals using the same frequency band or channel as the corresponding wireless signal processing unit of the transceiver unit 150 of the shared AP 10.

[0082] Alternatively, when the shared AP 20 communicates wirelessly with the shared AP 10, the transceiver unit 230, including the wireless signal processing unit, may not be provided. In this case, the shared AP 20 communicates wirelessly with the shared AP 10 via either the wireless signal processing units 240 or 250. Furthermore, in Figure 6 In the example, in shared AP 20, multiple wireless signal processing units 240 and 250 each constitute one auxiliary AP. For example, in shared AP 20-1, wireless signal processing unit 240 constitutes A-AP 1-1, and wireless signal processing unit 250 constitutes A-AP 1-2. Similarly, in shared AP 20-2, wireless signal processing unit 240 constitutes A-AP 2-1, and wireless signal processing unit 250 constitutes A-AP 2-2; in shared AP 20-3, wireless signal processing unit 240 constitutes A-AP 3-1, and wireless signal processing unit 250 constitutes A-AP 3-2.

[0083] The MAC frame processing unit 220 outputs data frames as MAC frames to one or more corresponding wireless signal processing units 240 and 250. At this time, the MAC frame processing unit 220 outputs data frames to one or more wireless signal processing units (240 and 250) corresponding to the link to which data (traffic) input from the transceiver unit 230 has been allocated.

[0084] When management information is input from either the transceiver unit 230 or the wireless signal processing units 240 and 250, the MAC frame processing unit 220 outputs the input management information to the management unit 210. Additionally, when management information for notification to the shared AP 10 is input from the management unit 210, the MAC frame processing unit 220 outputs the input management information to the transceiver unit 230. When management information for notification to the terminal 30 is input from the management unit 210, the MAC frame processing unit 220 generates a beacon frame as a management frame based on the input management information. Then, the MAC frame processing unit 220 outputs the generated beacon frame to at least one of the corresponding wireless signal processing units 240 and 250. Then, by transmitting a wireless signal transformed from the beacon frame from at least one of the corresponding wireless signal processing units 240 and 250, the management information contained in the beacon is communicated to the terminal 30.

[0085] The management information communicated by the shared AP 20 via beacon includes information about the shared AP 10, information about the shared AP 20 at this site, and information about the shared AP 20s at other sites belonging to the shared AP 10. Alternatively, the shared AP 20 may receive the aforementioned multi-AP management information 131 and terminal management information 132 from the shared AP 10, and the management unit 210 may communicate the multi-AP management information 131 and terminal management information 132 via beacon.

[0086] Additionally, the management unit 210 stores link management information 211 as management information regarding the wireless connection of the terminal 30 in a multi-AP connection mode. The link management information 211 indicates whether the shared AP 20 of this station is the connection target for each of the multiple links from the terminal 30. Furthermore, for the links where the shared AP 20 of this station is the connection target, the link management information 211 displays the identifier of the affiliated AP that is the connection target. For example, when shared AP 20-1 is the connection target, it indicates which of A-AP 1-1 and A-AP 1-2 (wireless signal processing units 240 and 250) is the connection target. The identifier of the affiliated AP may include the MAC address of the affiliated AP.

[0087] Additionally, the transceiver unit 230 receives instructions from the shared AP 10 regarding traffic allocation across multiple links from the terminal 30. The management unit 210, based on the allocation instructions from the shared AP 10, performs traffic allocation across links wirelessly connected to the shared AP 20 at this station. Then, based on the allocation results, the management unit 210 notifies the MAC frame processing unit 220 of the destination of the traffic sent to the terminal 30. Accordingly, the management unit 210 notifies the MAC frame processing unit 220 which output of the wireless signal processing units 240 and 250 is being used to send traffic to the terminal 30.

[0088] During the handover process, when the shared AP 10 sets up the handover target link and anchor link in response to the handover request, the transceiver unit 230 of the shared AP 20 receives configuration information regarding the handover target link and anchor link. Based on this, the management unit 210 obtains the configuration information regarding the handover target link and anchor link. The configuration information regarding the anchor link shows the identifier of the link serving as the anchor link, etc. Furthermore, the configuration information regarding the anchor link also indicates whether the anchor link belongs to the handover target link.

[0089] The configuration information for the handover target links shows the identifiers of each link. Furthermore, for each handover target link, the configuration information shows the shared AP 20 that is the object of the deassociation process for terminating the wireless connection, and the shared AP 20 that is the object of the association process for establishing a new wireless connection. Additionally, the configuration information for the handover target links may also show the affiliated APs that are the objects of deassociation processes and the affiliated APs that are the objects of association processes for each handover target link.

[0090] When the shared AP 20 at this site is the target of the deassociation process for the switching target link, the management unit 210 disconnects the wireless connection with the terminal 30 through the switching target link by performing the deassociation process. Then, in response to the completion of the deassociation process for each switching target link, the management unit 210 sends a notification message from the transceiver unit 230 to the shared AP 10 indicating that the deassociation process has been completed.

[0091] Furthermore, when the shared AP 20 at this station is the target of association processing for a switching target link, the management unit 210 establishes a new wireless connection with the terminal 30 through the switching target link by performing association processing. Then, in response to the completion of association processing for each switching target link, the management unit 210 sends a notification message from the transceiver unit 230 to the shared AP 10 indicating that the association processing is complete.

[0092] When the shared AP 20 at this site is the connection target of the anchor link, during the handover of the connection target shared AP 20 to a handover target link other than the anchor link, the management unit 210 maintains the wireless connection with the terminal 30 via the anchor link. This wireless connection with the terminal 30 is maintained until the deassociation and associativity processes for all handover target links other than the anchor link are completed.

[0093] Furthermore, during the handover of a connection target shared access point for a handover target link other than the anchor link, the management unit 210 outputs the traffic sent to the terminal 30 from the MAC frame processing unit 220 to the affiliated AP (wireless signal processing unit) that serves as the connection target of the anchor link. For example, when A-AP 1-1 of the shared AP 20-1 is the connection target of the anchor link, during the handover of a connection target for a handover target link other than the anchor link, data is sent from A-AP1-1 to the terminal 30 via the anchor link.

[0094] Furthermore, when the shared AP 20 at this station is the connection target of the anchor link and the anchor link is the handover target, the management unit 210, based on the fact that the handover of the connection target shared AP 20 has been completed for all handover target links other than the anchor link, cuts off the wireless connection between the terminal 30 and the anchor link. Therefore, based on the fact that the handover of the connection target shared AP 20 has been completed for all handover target links other than the anchor link, the management unit 210 performs deassociation processing and associativity processing for the anchor link.

[0095] Furthermore, in one example, in the shared AP 20, multiple auxiliary APs are each composed of a wireless signal processing unit (one of 240 and 250) and a quality measurement unit. In this case, in each of the multiple auxiliary APs, the quality measurement unit measures the communication quality of the link from the auxiliary STA of terminal 30. The quality measurement unit measures the link communication quality by measuring the received power, etc., from the auxiliary STA of terminal 30. Then, in each auxiliary AP, the quality measurement unit notifies the management unit 210 of the measurement results regarding the communication quality of the link from the auxiliary AP of terminal 30.

[0096] Figure 7 This is a block diagram illustrating an example of the functional structure of a terminal according to an embodiment. The terminal 30 functions as a computer comprising an application execution unit 300, an LLC processing unit 310, a management unit 330, a MAC frame processing unit 340, wireless signal processing units 350 and 360, and quality measurement units 370 and 380. The application execution unit 300 is a functional block that performs processing corresponding to Layer 7. The LLC processing unit 310 is a functional block that performs processing corresponding to the LLC sublayer of Layer 2 and Layers 3 through 6. The management unit 330 and the MAC frame processing unit 340 are functional blocks that perform processing corresponding to the MAC sublayer of Layer 2. The wireless signal processing units 350 and 360 and the quality measurement units 370 and 380 are functional blocks that perform processing corresponding to the MAC sublayer of Layer 2 and Layer 1.

[0097] The application execution unit 300 executes the application based on data input from the LLC processing unit 310. Additionally, the application execution unit 300 inputs data to the LLC processing unit 310. For example, the application execution unit 300 can display application information on the display 35. Furthermore, the application execution unit 300 can operate based on the operation of the input interface.

[0098] The LLC processing unit 310, which also functions as a data processing unit, appends DSAP or SSAP headers to the data input from the application execution unit 300 to generate LLC data packets. Then, the LLC processing unit 310 outputs the generated LLC data packets to the MAC frame processing unit 340. Additionally, the LLC processing unit 310 extracts data from the LLC data packets input from the MAC frame processing unit 340. Then, the LLC processing unit 310 outputs the extracted data to the application execution unit 300.

[0099] The management unit 330 controls the connection (logical wireless connection) between the shared AP 10 and the non-AP type MLD of the terminal 30 in a multi-AP connection mode. The terminal 30 receives a beacon from the shared AP 20, thereby allowing the management unit 330 to obtain the management information contained in the beacon. In one example, the terminal 30 receives the beacon from the shared AP 20, thereby allowing the management unit 330 to obtain the aforementioned multi-AP management information 131 and terminal management information 132, etc. The management unit 330 manages the management information contained in the beacon. Then, based on the management information, the management unit 330 controls the wireless connection with the target shared AP 20 for links from the affiliated STAs, namely each A-STA1 and A-STA2.

[0100] Additionally, the management unit 330 stores link management information 331. In the link management information 331, identifiers of the target shared AP 20 are displayed for each of the multiple links from the terminal 30. Furthermore, in the link management information 331, identifiers of the auxiliary APs in the wireless connections of the target shared AP 20 are displayed for each of the multiple links.

[0101] The MAC frame processing unit 340 appends a MAC header to the LLC data packet input from the LLC processing unit 310 to generate a MAC frame. Then, the MAC frame processing unit 340 distributes the generated MAC frame to the radio signal processing units 350 and 360. At this time, the MAC frame is output to at least one of the corresponding radio signal processing units 350 and 360 (A-STA1 and A-STA2). Additionally, the MAC frame processing unit 340 extracts LLC data packets or management information from the MAC frames input from the radio signal processing units 350 and 360, respectively. Then, the MAC frame processing unit 340 outputs the LLC data packet to the LLC processing unit 310 and the management information to the management unit 330.

[0102] In terminal 30, a non-AP type MLD is constructed by a management unit 330 and a MAC frame processing unit 340, etc. Additionally, in Figure 7 In the example, in terminal 30, A-STA1, one of the auxiliary STAs, is composed of wireless signal processing unit 350 and quality measurement unit 370, while A-STA2, the other auxiliary STA, is composed of wireless signal processing unit 360 and quality measurement unit 380. Wireless signal processing unit 350 and quality measurement unit 370 have the same functional structure as wireless signal processing unit 360 and quality measurement unit 380, respectively. Furthermore, in one example, a quality measurement unit can be set up for each auxiliary AP in the shared AP 20, and a quality measurement unit may not be set up for each auxiliary STA of terminal 30. In this case, each auxiliary AP also includes a wireless signal processing unit (one of 350 and 360).

[0103] Wireless signal processing units 350 and 360 respectively add preambles, etc., to the MAC frames input from MAC frame processing unit 340 to generate wireless frames. Then, wireless signal processing units 350 and 360 respectively convert the generated wireless frames into wireless signals and transmit (radiate) the converted wireless signals via antennas. The conversion process from wireless frames to wireless signals is performed in the manner described above.

[0104] Furthermore, the wireless signal processing units 350 and 360 respectively convert the wireless signals received from the corresponding shared AP 20 via the antenna into wireless frames. The conversion process from wireless signal to wireless frame is performed in the manner described above. The wireless signal processing units 350 and 360 respectively extract MAC frames from the converted wireless frames and output the extracted MAC frames to the MAC frame processing unit 340.

[0105] Quality measurement units 370 and 380 measure the communication quality of the link (wireless link) from wireless signal processing units 350 and 360 (A-STA1 and A-STA2) by measuring the received power from the affiliated APs that exist within the detectable range of the shared AP 20. Then, in each of the multiple affiliated STAs of terminal 30, the quality measurement unit (one of 370 and 380) notifies the management unit 330 of the measurement results regarding the communication quality of the link.

[0106] Based on the communication quality measurement results from the quality measurement units 370 and 380, the management unit 330 determines whether to notify the shared AP 10 of a handover request. For example, if there is a link with a received power below a threshold in the links from the wireless signal processing units 350 and 360, the management unit 330 notifies the shared AP 10 of a handover request via any shared AP 20. When the shared AP 10 sets up an anchor link in response to the handover request, a handover response is sent from any shared AP 20 to the terminal 30. Then, by receiving the handover response through the terminal 30, the management unit 330 obtains the setting information about the anchor link.

[0107] In response to notification of anchor link configuration information, management unit 330 switches the connection target for each handover target link other than the anchor link. At this time, for each handover target link other than the anchor link, it performs deassociation processing to disconnect the wireless connection from the shared AP 20 in the wireless connection and association processing to establish a wireless connection with the shared AP 20 as the new connection target. Furthermore, during the handover of the connection target shared AP 20 for the handover target links other than the anchor link, management unit 330 allocates (maps) the traffic transmitted and received between the anchor link and the shared AP 10.

[0108] Furthermore, when the anchor link is the target of the connection switch, the management unit 330, based on the fact that the connection target shared AP 20 has been switched for all switching targets other than the anchor link, notifies the shared AP 10 of the connection target switch request for the anchor link via any shared AP 20. Then, via any shared AP 20, the shared AP 10 notifies the management unit 330 of the terminal 30 of the response to the switch request for the anchor link, i.e., the connection target switch response for the anchor link.

[0109] In response to being instructed to switch the connection target of the anchor link in the anchor link handover response, the management unit 330 switches the connection target for the anchor link. At this time, it performs the deassociation process of severing the wireless connection with the shared AP 20 in the wireless connection and the association process of establishing a wireless connection with the shared AP 20 as the new connection target for the anchor link.

[0110] During the switchover of connection targets for the anchor link, the management unit 330 allocates traffic to and from the shared AP 10 for all links other than the anchor link among the multiple links. Therefore, during the switchover of connection targets for the anchor link, the traffic corresponding to the anchor link is allocated to links other than the anchor link. Furthermore, when the switchover and handover of connection targets for the anchor link are completed, the management unit 330 allocates traffic to and from the shared AP 10 for all multiple links, including the anchor link.

[0111] Next, the operation of the communication system according to the implementation method will be explained, especially the handover process. Figure 8 This is a flowchart illustrating an example of the processing in a handover operation performed by a communication system according to an embodiment. Figure 8 The example shown involves processing performed by the management unit 130 of the shared AP 10, the management units 210 of each of the shared APs 20, and the management unit 330 of the terminal 30. Additionally, in Figure 8 The example illustrates the case where terminal 30 can establish more than 3 links and there are more than 2 handover target links other than the anchor link.

[0112] When a handover operation begins in response to a handover request from terminal 30, management unit 130 sets anchor link L0 from multiple links (S51) and sets handover target links L1 to Ln (n being an integer of 2 or more) other than anchor link L0 (S52). At this time, for example, anchor link L0 is numbered "0", and handover target links L1 to Ln other than anchor link L0 are numbered "1" to "n" respectively. Anchor link L0 and handover target links L1 to Ln are set in the aforementioned manner based on communication quality such as received power. Furthermore, when only a portion of the multiple links are handover targets, it is preferable to set anchor link L0 from links other than the handover target links.

[0113] exist Figure 8The example specifies a decision parameter k. The decision parameter k can be set to an integer greater than 1 and less than n. Management unit 130 sets the decision parameter k to an initial value of 1 (S53). Then, management unit 130, in cooperation with management unit 210 of the corresponding shared AP 20 and management unit 330 of the terminal 30, performs a handover process for the connection target of the handover target link Lk (S54). At this time, for the handover target link Lk, a process of deassociating it with the shared AP 20 in the wireless connection and an association process with the shared AP 20 as the new connection target are performed. Furthermore, during the handover process of the handover target link Lk, traffic transmitted and received between the shared AP 10 and the terminal 30 is allocated to the anchor link L0. Moreover, the association between the link Lk specified by the decision parameter k and the link ID is arbitrary; the link Lk is not directly associated with the ascending link ID.

[0114] When the switching process for the target link Lk is completed, the management unit 130 and others determine whether the value of the determination parameter k is n (S55). Then, if the value of the determination parameter k is less than n (S55: No), the management unit 130 and others increment the value of the determination parameter k by 1 (S56). Then, the process returns to S54, and the processes after S54 are performed sequentially. Therefore, the processes of S54 to S56 are repeated until the value of the determination parameter k is n. Accordingly, the connection target switching process is performed for each target link L1 to Ln.

[0115] When the value of parameter k is n (S55: Yes), the management unit 130 determines whether anchor link L0 is the target for connection switching (S57). Then, when anchor link L0 is the target for switching (S57: Yes), the management unit 130, in cooperation with the management unit 210 of the corresponding shared AP 20 and the management unit 330 of the terminal 30, performs the connection target switching process for anchor link L0 (S58). At this time, the anchor link L0 is de-associated with the shared AP 20 in the wireless connection and associated with the shared AP 20 as the new connection target. In addition, during the anchor link L0 switching process, the traffic transmitted and received between the shared AP 10 and the terminal 30 is allocated to links other than anchor link L0. When anchor link L0 is the target for switching (S57: No), the process in S58 is not performed.

[0116] Furthermore, when there is only one switching target link other than the anchor link, switching target link L1 is set. Then, when the switching process of the connection target of switching target link L1 is completed, it is determined whether the anchor link L0 is the target of the switching connection. Additionally, in Figure 8In the example, the connection targets of the switching object links L1 to Ln are switched sequentially through the processing of S53 to S56. However, in a certain example, the switching of the connection targets of the switching object links L1 to Ln can also be performed in parallel. However, when the connection targets of the switching object links L1 to Ln are switched in parallel, the connection target switching processing of the anchor link L0 is also performed based on the condition that the connection target switching has been completed for all switching object links L1 to Ln.

[0117] Figure 9 This is a schematic diagram illustrating an example of the handover process of a communication system according to an implementation method. Figure 9 In the example, the handover process begins with a link from A-STA1 wirelessly connected to A-AP 1-1 of shared AP 20-1, and a link from A-STA2 wirelessly connected to A-AP 2-2 of shared AP 20-2. The link from A-STA2 is then designated as the anchor link. Therefore, when the handover begins, while maintaining the wireless connection between the anchor link (the link from A-STA2) and shared AP 20-2, the connection target for the link from A-STA1 is switched. At this point, the wireless connection from the link from A-STA1 to shared AP 20-1 is severed through a deassociation process, and a wireless connection from the link from A-STA1 to A-AP 2-1 of shared AP 20-2 is established through an association process.

[0118] Then, when the connection target switching of the link from A-STA1 is completed, the connection target switching is performed on the anchor link, i.e., the link from A-STA2. At this time, through the deassociation process, the wireless connection from the link from A-STA2 to the shared AP20-2 is cut off, and through the association process, a wireless connection is established for the link from A-STA2 to the shared AP20-3's A-AP3-2.

[0119] Figure 10 This is a sequence diagram illustrating an example of communication processing based on a multi-AP connection method during the handover of work in the communication system of the embodiment. Figure 10 The process is shown in the figure. Figure 9 The example demonstrates communication processing during job handover. Additionally, Figure 10 The diagram shows the information flow exchanged between shared AP 10, shared APs 20-1 to 20-3, affiliated STAs A-STA1 and A-STA2, and non-AP type MLDs.

[0120] exist Figure 10In the example, before the handover process begins, the communication quality measurement results, such as the received power of the links from each A-STA1 and A-STA2, are notified to the non-AP type MLD (S61). Then, based on the communication quality measurement results, the non-AP type MLD determines that a connection target needs to be switched for the links from each A-STA1 and A-STA2, and sends a handover request to the shared AP 10 (S62). The handover request is sent using any one or more links from A-STA1 and A-STA2. In addition, the handover request is sent together with the communication quality measurement results for each of the multiple links from the terminal 30.

[0121] When the shared AP 10 receives a handover request, it sets up an anchor link as described above and notifies its parent shared APs 20-1 to 20-3 of the anchor link configuration information (S63). Furthermore, when the anchor link is set, the shared AP 10, in cooperation with non-AP type MLDs, allocates traffic transmitted and received between the shared AP 10 and terminal 30 via the shared AP 20 to the anchor link. Then, the non-AP type MLD of terminal 30 receives a handover response as a reply to the handover request (S64). At this time, along with the handover response, the non-AP type MLD is notified of the anchor link configuration information, etc. Furthermore, in Figure 10 In the example, the handover response is sent from the shared AP 20-2, which is wirelessly connected to the anchor link (the link from A-STA2), via the anchor link. However, the handover response can also be sent via a link other than the anchor link.

[0122] Then, the non-AP type MLD sends the connection target handover request for the handover target link other than the anchor link to the corresponding shared AP 20 (S65). Figure 10 In the example, a deassociation request is sent to the shared AP 20-1, which is wirelessly connected to the link from A-STA1, and an association request is sent to the shared AP 20-2, which is the new connection target of the link from A-STA1. Then, the non-AP type MLD receives a handover response for the connection target link other than the anchor link from the corresponding shared AP 20 as a response to the handover request for the non-anchor link (S66). When the non-AP type MLD receives a handover response for the non-anchor link, it performs connection target handover processing for the handover target link other than the anchor link.

[0123] Then, when the connection target of the switching target link other than the anchor link is switched, the corresponding shared AP 20 notifies the shared AP 10 that the connection target switch is complete (S67). Figure 10In the example, the shared AP 20-1 notifies that the deassociation process is complete, and the shared AP 20-2 notifies that the associativity process is complete. Additionally, when the connection target of a switching target link other than the anchor link is switched, the corresponding subordinate STA notifies the non-AP type MLD that the connection target switchover is complete (S68). Figure 10 In the example, A-STA1 notifies the deassociation process and the completion of the associativity process. Furthermore, when multiple handover target links exist besides the anchor link, the same communication processes as in S65-S68 are repeated the same number of times as the number of handover target links besides the anchor link.

[0124] When the handover of the connection target other than the anchor link is completed, the non-AP type MLD sends a connection target handover request for the anchor link to the shared AP 10 (S69). Then, the non-AP type MLD receives a connection target handover response for the anchor link from the shared AP 10 as a response to the handover request for the anchor link (S70). When the handover request for the anchor link is received, the shared AP 10 and the non-AP type MLD cooperate to allocate the traffic transmitted and received between the shared AP 10 and the terminal 30 to links other than the anchor link.

[0125] Then, the non-AP type MLD sends a connection target switching request for the anchor link to the corresponding shared AP 20 (S71). Figure 10 In the example, a deassociation request is sent to the shared AP 20-2, which is wirelessly connected to the anchor link (i.e., the link from A-STA2), and an association request is sent to the shared AP 20-3, which is the new connection target of the link from A-STA2. Then, the non-AP type MLD receives a connection target handover response for the anchor link from the corresponding shared AP 20 as a response to the handover request for the anchor link (S72). When the non-AP type MLD receives the handover response for the anchor link, it performs connection target handover processing for the anchor link.

[0126] Then, when the connection target of the anchor link is switched, the corresponding shared AP 20 notifies the shared AP 10 that the connection target switch is complete (S73). Figure 10 In the example, the shared AP 20-2 notifies that the deassociation process is complete, and the shared AP 20-3 notifies that the associativity process is complete. Additionally, when the connection target of the anchor link is switched, the corresponding subordinate STA notifies the non-AP type MLD that the connection target switch has been completed (S74). Figure 10 In the example, notifications from A-STA2 indicate the completion of the deassociation process and the association process. Furthermore, when the anchor link is not the switching target, communication processes S69-S74 are not performed.

[0127] also, Figure 9 and Figure 10 The diagram illustrates an example where two links from terminal 30 are wirelessly connected to different shared APs 20 before and after the handover process. However, even if, before and after the handover process, at least one of the two links from terminal 30 is wirelessly connected to the same shared AP 20, there is still a conflict with... Figure 9 The same handover process is performed as in the example, with the handover process... Figure 10 The example also performs communication processing.

[0128] For example, suppose the connection target of the links from each A-STA1 and A-STA2 is switched from shared AP 20-1 to shared AP 20-2 through a handover process. In this case, before the handover, the two links from terminal 30 were wirelessly connected to the same shared AP 20-1, and after the handover, they are wirelessly connected to the same shared AP 20-2. Also in this case, one of the two links is designated as the anchor link, and while maintaining the wireless connection with shared AP 20-1 through the anchor link, the connection target of the link other than the anchor link is switched. Then, based on the completion of the switch of the connection target of the link other than the anchor link, the connection target of the anchor link is switched. Additionally, during the handover process, with... Figure 10 The example also performs communication processing.

[0129] In this embodiment, as described above, during the handover process, one of the multiple links from terminal 30 is designated as the anchor link. While maintaining a wireless connection with the target AP 20 via the anchor link, the target AP 20 is switched to a different handover link than the anchor link. Because the handover of the target AP 20 to a different link is performed while maintaining a wireless connection with the anchor link, the occurrence of momentary interruptions that could result in the loss of wireless connection with the shared AP 20 across all links from terminal 30 is effectively suppressed during the handover process. Therefore, the target AP 20 is appropriately switched to a different handover link from terminal 30 without causing momentary interruptions.

[0130] Furthermore, in this embodiment, when the anchor link is the switching target, the connection target shared AP 20 is switched for the anchor link only, based on the case where the switching of the connection target shared AP 20 has been completed for all switching target links other than the anchor link. Therefore, even in cases where the connection target of the link set as the anchor link needs to be switched during the handover process, such as when the connection target of the link is switched for all multiple links from the terminal 30, the occurrence of momentary interruption is effectively suppressed.

[0131] By suppressing transient interruptions, the stability of the connection between the shared AP10 and the terminal 30 is ensured even during handover operations. Furthermore, because transient interruptions are suppressed, it is no longer necessary to separately configure a wireless communication system connecting the shared AP10 and the terminal 30 from the communication system 1 that connects the shared AP10 and the terminal 30 via any shared AP 20. Therefore, power saving can be achieved in the system architecture for data exchange between the shared AP10 and the terminal 30.

[0132] Furthermore, in this embodiment, during the handover of the connection target shared AP 20 to a switching target link other than the anchor link, the traffic transmitted and received between the shared AP 10 and the terminal 30 is allocated to the anchor link. Additionally, during the handover of the connection target shared AP 20 to the anchor link, the traffic transmitted and received between the shared AP 10 and the terminal 30 is allocated to links other than the anchor link. Therefore, even when the connection target of each switching target link is being switched through a handover operation, data exchange between the shared AP 10 and the terminal 30 is appropriately performed.

[0133] Furthermore, while the aforementioned embodiments primarily described the case where two auxiliary STAs are configured on terminal 30, terminal 30 can have any structure with multiple auxiliary STAs, and more than three auxiliary STAs can also be configured on terminal 30. Additionally, while the aforementioned embodiments primarily described the case where two auxiliary APs are configured on each shared AP 20, more than three auxiliary APs can also be configured on terminal 30. Alternatively, only one auxiliary AP can be configured on each shared AP 20.

[0134] For example, suppose four shared APs 20-1, 20-2, 20-3, and 20-4 are each set as shared APs belonging to shared AP 10, with each of the shared APs 20-1 to 20-4 having only one affiliated AP. Then, suppose that through a handover process, the connection target of one of the two links from terminal 30 is switched from shared AP 20-1 to shared AP 20-3, and the connection target of the other of the two links from terminal 30 is switched from shared AP 20-1 to shared AP 20-3. In this case, also during the handover process, the same processing as described above is performed by management units 130, 210, and 330. Therefore, one of the two links is set as the anchor link, and while maintaining the wireless connection of the anchor link, the connection target of the link other than the anchor link is switched. Then, based on the fact that the switching of the connection target of the link other than the anchor link has been completed, the connection target of the anchor link is switched.

[0135] Furthermore, in the aforementioned embodiments, the functions of the shared AP and the shared AP are completely separate. However, in a certain variation, the shared AP can also possess the functions of a shared AP. For example, in conjunction with... Figure 1 In the same communication system 1, the shared AP 10 can perform the processing of the shared AP 20-1 in addition to the aforementioned processing. In this case, as a functional structure, the shared AP 10, in addition to having an LLC processing unit 110, a data processing unit 120, a management unit 130, a frame processing unit 140, and a transceiver unit 150, also has a management unit 210, a MAC frame processing unit 220, and wireless signal processing units 240 and 250.

[0136] In the shared AP 10 with shared AP functionality, the transceiver unit 150 transmits and receives data and management information with the associated shared APs 20 (i.e., each shared AP 20-2, 20-3) via wireless or wired communication. Then, in the shared AP 10, the wireless signal processing units 240 and 250 can transmit and receive data and management information with the terminal 30 via wireless communication. Furthermore, the frame processing unit 140 included in the shared AP 10's functionality exchanges data and management information with the MAC frame processing unit 220 included in the shared AP's functionality. When the shared AP 10 with shared AP functionality is provided, the same processing as described in the aforementioned embodiment is performed through the shared AP 10, the shared APs 20 belonging to the shared AP 10, and the terminal 30.

[0137] Furthermore, in the aforementioned embodiments, the connection between the shared AP 10 and the terminal 30 is via one shared AP. However, in a certain variation, the connection between the shared AP and the terminal may be via two or more shared APs. That is, in a multi-AP connection method with a multi-level structure where there are two or more shared APs between the shared AP and the terminal, the processing described in the aforementioned embodiments can also be applied.

[0138] Furthermore, the processes described in the aforementioned embodiments can be stored as a program that can be executed by a computer processor. Additionally, the program for executing the aforementioned processes can be stored and distributed in a storage medium on an external storage device such as a disk, optical disk, or semiconductor memory. Then, the processor reads the program stored in the storage medium of the external storage device and controls the operation using the read program, thereby enabling the execution of the processes described in the embodiments.

[0139] 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 the desired 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. A shared access point having a management unit, wherein the management unit: in a state where a plurality of links from a terminal are respectively wirelessly connected to one of a plurality of shared access points, in response to receiving a handover request from the terminal requesting switching of a connection target shared access point for one or more of the plurality of links, sets one of the plurality of links as an anchor link, in a state where the anchor link maintains a wireless connection with the connection target shared access point, switches the connection target shared access point for a switching target link that is a switching target among links other than the anchor link.

2. The shared access point according to claim 1, wherein in a case where the anchor link is the switching target, the management unit switches the connection target shared access point for the anchor link based on a situation where switching of the connection target shared access point is completed for all the switching target links other than the anchor link.

3. The shared access point according to claim 1 or 2, wherein the management unit, in response to setting the anchor link, allocates traffic transmitted and received between the terminal to the anchor link during switching of the connection target shared access point for the switching target link other than the anchor link.

4. A terminal having: a plurality of wireless signal processing units that respectively establish one corresponding link among a plurality of links and are respectively wirelessly connected to one of a plurality of shared access points via the one corresponding link among the plurality of links; and a management unit that transmits a handover request requesting switching of a connection target shared access point for one or more of the plurality of links and, based on a situation where a shared access point sets one of the plurality of links as an anchor link in response to the handover request, switches the connection target shared access point for a switching target link that is a switching target among links other than the anchor link in a state where the anchor link maintains a wireless connection with the connection target shared access point.

5. The terminal according to claim 4, wherein in a case where the anchor link is the switching target, the management unit switches the connection target shared access point for the anchor link based on a situation where switching of the connection target shared access point is completed for all the switching target links other than the anchor link.

6. The terminal according to claim 4 or 5, wherein the management unit, in response to the anchor link being set by the shared access point, allocates traffic transmitted and received between the shared access point to the anchor link during switching of the connection target shared access point for the switching target link other than the anchor link.

7. A shared access point set as one of a plurality of shared access points, the shared access point having a management unit, wherein the management unit: in a state where a plurality of links from a terminal are respectively wirelessly connected to one of the plurality of shared access points, in response to the terminal transmitting a handover request requesting switching of a connection target shared access point for one or more of the plurality of links, acquires setting information about an anchor link that is one link among the plurality of links from a shared access point, In a case where the shared access point belongs to a connection target of the anchor point link, during a period in which handover of the shared access point is performed as a handover target link in a link other than the anchor point link, the wireless connection with the terminal via the anchor point link is maintained.

8. The shared access point according to claim 7, wherein In a case where the shared access point belongs to a connection target of the anchor point link and the anchor point link is the handover target, the management section cuts off the wireless connection with the terminal via the anchor point link based on a situation in which handover of the shared access point is completed for all the handover target links other than the anchor point link.

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