Access point and terminal device

Abstract

An access point according to an embodiment includes an acquisition unit and a control unit. The acquisition unit acquires information indicating that a terminal device to be handed over is a priority terminal for which data communication is prioritized. The data communication is executed with the priority terminal for which handover to the host device serving as a handover destination is completed, the data communication being executed during an allocated period of a scheduled restricted-target wake time service period (R-TWT SP) until a predetermined time elapses from the point when the handover is completed.

Description

Access points and terminal devices

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

[0002] IEEE 802.11be standardizes multi-link transmission, in which multiple links (transmission paths) with different frequency channels are established between a terminal device and an access point. Furthermore, the next generation of IEEE 802.11 standards is considering a multi-AP function that enables multiple access points to communicate in a coordinated and cooperative manner. The R-TWT (restricted target wake time) function is also known as a method for transmitting and receiving low-latency traffic between an access point and a terminal device. An access point using the R-TWT function sets an R-TWT service period (hereinafter referred to as R-TWT SP) at a period corresponding to the required latency of the low-latency traffic and notifies the terminal device of the set service period using a management frame such as a beacon or an action frame. Then, when a terminal device handling low-latency traffic detects the allocation of an R-TWT SP to itself through a received beacon or the like, it deterministically transmits the low-latency traffic to the access point. An information communication system that utilizes the R-TWT function can reduce delay and jitter in low-latency traffic.

[0003] IEEE802.11be D4.1, “35.8 Restricted TWT (R-TWT)”, p622-p627, September 2023IEEE802.11-23 / 1499r0, September 2023

[0004] However, when a terminal device uses the R-TWT function and a handover is performed between access points, depending on the scheduling of the R-TWT SP at the handover destination, an R-TWT SP with which the terminal device can communicate may not be assigned easily, resulting in a decrease in transmission opportunities. In the case of data communication that requires low latency, such as using the R-TWT function, there is a problem that such a decrease in transmission opportunities leads to an increase in latency.

[0005] The present invention has been made in light of the above circumstances, and an object of the present invention is to provide an access point and a terminal device that can satisfy the demand for low-latency traffic.

[0006] The access point according to the embodiment includes an acquisition unit and a control unit. The acquisition unit acquires information indicating that a terminal device to be handed over is a priority terminal for which data communication is prioritized. The access point executes the data communication with the priority terminal that has completed handover to the access point as a handover destination during an allocation period of a restricted-target wake time service period (R-TWT SP) scheduled for a predetermined time period from the time the handover is completed until the time a predetermined time period has elapsed.

[0007] Moreover, the access point of the embodiment includes an acquisition unit, a determination unit, and a control unit. The acquisition unit acquires information indicating that a terminal device to be handover is a priority terminal for which data communication is prioritized. The determination unit determines whether a transmission interval from the start of the handover of the priority terminal to a timing corresponding to a period of an R-TWT SP (restricted-target wake time service period) assigned by a handover source in the access point that is the handover destination is equal to or greater than a threshold. If it is determined that the transmission interval is equal to or greater than the threshold, the control unit executes the data communication with the priority terminal for which the handover has been completed, during an R-TWT SP assignment period scheduled from the time the handover has been completed until a predetermined time has elapsed.

[0008] In addition, the terminal device of the embodiment includes a notification unit and a control unit. The notification unit notifies a first access point that is a handover source that the terminal device is a priority terminal in which data communication is prioritized. When handover to a second access point that is a handover destination is completed, the control unit performs the data communication with the second access point during an allocation period of a restricted-target wake time service period (R-TWT SP) scheduled from the time the handover is completed until a predetermined time has elapsed.

[0009] According to the embodiment, it is possible to provide an access point and a terminal device that can satisfy the demand for low latency traffic.

[0010] FIG. 1 is a block diagram showing an example of the overall configuration of an information communication system according to the first embodiment. FIG. 2 is a block diagram showing an example of the hardware configuration of a sharing AP according to the first embodiment. FIG. 3 is a block diagram showing an example of the hardware configuration of a shared AP according to the first embodiment. FIG. 4 is a block diagram showing an example of the hardware configuration of a terminal device according to the first embodiment. FIG. 5 is a block diagram showing an example of the functional configuration of a sharing AP according to the first embodiment. FIG. 6 is a block diagram showing an example of the functional configuration of a shared AP according to the first embodiment. FIG. 7 is a block diagram showing an example of the functional configuration of a terminal device according to the first embodiment. FIG. 8 is a sequence diagram showing an example of handover processing in the information communication system according to the first embodiment. FIG. 9 is a diagram showing a first example of data communication of a priority terminal before and after handover according to the first embodiment. FIG. 10 is a diagram showing a second example of data communication of a priority terminal before and after handover according to the first embodiment. FIG. 11 is a block diagram showing an example of the functional configuration of a shared AP according to the second embodiment. FIG. 12 is a flowchart showing an example of determining an allocation period to a priority terminal after handover according to the second embodiment is completed.

[0011] Each embodiment will be described below with reference to the drawings. Each embodiment illustrates an apparatus or method for embodying the technical concept of the invention. The drawings are schematic or conceptual. Hereinafter, the same reference numerals are used to designate components having substantially the same functions and configurations. The numerals following the letters in a reference numeral are used to distinguish between elements having similar configurations and referenced by the same reference numerals. Similarly, the letters and "hyphen + numeral" following the numerals in a reference numeral are used to distinguish between elements having similar configurations and referenced by the same reference numerals. When it is not necessary to distinguish between elements indicated by the same reference numerals, these elements are referred to by the reference numerals containing only the letters or numerals. Hereinafter, "access point" will be abbreviated to "AP" as appropriate. In this specification, an access point may also be referred to as a "base station."

[0012] First Embodiment An example of the overall configuration of an information communication system 1 according to a first embodiment will be described with reference to the block diagram of Fig. 1. As shown in Fig. 1, the information communication system 1 includes a sharing access point (AP) 10, a shared access point (AP) 20, and a terminal device 30. The terminal device 30 includes a non-AP_MLD (non-access point multi-link device) and multiple affiliated STAs (affiliated STA #1 and affiliated STA #2).

[0013] In the information communication system 1 according to the first embodiment, a shared AP 20 and a terminal device 30 establish a multi-link connection. Here, it is assumed that an R-TWT SP is scheduled on a single link, and any communication may be performed on other links. Note that the same processing can be performed even when an R-TWT SP is replicated on multiple links and scheduled on multiple links at the same time.

[0014] The sharing AP 10 is a type of access point for a wireless LAN (Local Area Network). The sharing AP 10 is connected to a network NW by wire or wirelessly and configured to communicate by wire or wirelessly with a server (not shown) on the network NW or with other sharing APs 10. The sharing AP 10 is also connected to multiple shared APs 20 by wire or wirelessly and configured to communicate by wire or wirelessly with each of the multiple shared APs 20. In the example of FIG. 1 , two shared APs, 20-1 and 20-2, are connected to one sharing AP 10-1, and similarly, shared APs 20-3 and 20-4 are connected to the sharing AP 10-2. However, this is not a limitation, and three or more shared APs 20 may be connected to one sharing AP 10.

[0015] The shared AP 20 is a type of wireless LAN access point. The shared AP 20 is configured to communicate with the sharing AP 10 via wired or wireless communication. The shared AP 20 is wirelessly connected to an affiliated STA of the terminal device 30 and configured to communicate wirelessly with the affiliated STA of the terminal device 30. The multiple shared APs 20 are installed at locations separated from each other and have different communication areas. The communication area of ​​each shared AP 20 may partially overlap with the communication areas of other shared APs 20.

[0016] The terminal device 30 is, for example, a wireless terminal such as a smartphone or a PC (Personal Computer). The non-AP_MLD of the terminal device 30 is a multi-link device (MLD) that manages the link status and wireless communication of each of multiple affiliated STAs. The non-AP_MLD can also perform processing for establishing multi-links between multiple shared APs 20 and the terminal device 30. Each affiliated STA corresponds to a wireless signal processing unit that can establish a wireless link with the shared AP 20. The terminal device 30 is assumed to include two affiliated STAs, affiliated STA #1 and affiliated STA #2, but may include three or more affiliated STAs.

[0017] 1, in the terminal device 30, the affiliated STA #1 is wirelessly connected to the shared AP 20-2 (link #1), and the affiliated STA #2 is wirelessly connected to the shared AP 20-4 (link #2). It is assumed that the communication using the R-TWT function is performed between the shared AP 20 and the affiliated STA #1 in the link #1.

[0018] This embodiment assumes a handover, and as the terminal device 30 moves, the affiliated STA can switch its connection destination to another shared AP 20. Here, it is assumed that the terminal device 30 moves toward a BSS (basic service set) formed by the shared AP 20-3. It is assumed that before and after the handover, the link #2 of the affiliated STA #2 remains connected between the affiliated STA #2 and the shared AP 20-3, while the connection of the link #1 of the affiliated STA #1 switches from the shared AP 20-2 to the shared AP 20-4.

[0019] The wireless communication used in the information and communication system 1 complies with, for example, the IEEE 802.11 standard. The IEEE 802.11 standard has wireless communication functions based on the OSI (Open Systems Interconnection) reference model. In the OSI reference model, wireless communication functions are divided into seven layers (Layer 1: Physical Layer, Layer 2: Data Link Layer, Layer 3: Network Layer, Layer 4: Transport Layer, Layer 5: Session Layer, Layer 6: Presentation Layer, and Layer 7: Application Layer). The data link layer includes a Logical Link Control (LLC) sublayer and a Media Access Control (MAC) sublayer. Frequency bands used in the wireless communication of the information and communication system 1 include, for example, the 2.4 GHz band, the 5 GHz band, the 6 GHz band, the 45 GHz band, and the 60 GHz band. Multiple channels are assigned to each frequency band.

[0020] Furthermore, in the information communication system 1, each of the sharing AP 10, the shared AP 20, and the terminal device 30 supports the R-TWT function. The R-TWT function is a function that allocates a service period during which traffic requiring low latency can be preferentially exchanged to the terminal device 30. Note that traffic requiring low latency is called "low latency traffic."

[0021] A shared AP 20 using the R-TWT function assigns an R-TWT SP to a link and gives a terminal device 30 a preferential frame exchange opportunity. The frame exchange opportunity corresponds to an opportunity for traffic (data) to be transmitted by frame exchange. For example, the terminal device 30 transmits low-latency traffic to the shared AP 20 based on receiving a trigger frame from the shared AP 20 at the R-TWT SP. In this way, the R-TWT function can improve the latency of low-latency traffic by giving priority to communication of the low-latency traffic of the terminal device 30 at the R-TWT SP.

[0022] Next, an example of the hardware configuration of the sharing AP 10 will be described with reference to the block diagram of Fig. 2. As shown in Fig. 2, the sharing AP 10 includes a CPU (Central Processing Unit) 11, a ROM (Read Only Memory) 12, a RAM (Random Access Memory) 13, a wireless communication module 14, and a wired communication module 15.

[0023] The CPU 11 is an integrated circuit capable of executing various programs and controls the overall operation of the sharing AP 10. The ROM 12 is, for example, a non-volatile semiconductor memory that stores programs and control data for controlling the sharing AP 10. The RAM 13 is, for example, a volatile semiconductor memory that is used as a work area for the CPU 11. The wireless communication module 14 is a circuit used to send and receive data and the like between the shared APs 20-1 and 20-2. The wired communication module 15 is a circuit used to send and receive data and the like via wired signals and is configured to be connectable to the network NW.

[0024] The sharing AP 10 may have other hardware configurations. For example, the sharing AP 10 may be wirelessly connected to the network NW. In this case, a wireless communication module may be used instead of the wired communication module 15. In this case, the antenna may be built into the sharing AP 10 or may be externally connected. The sharing AP 10 may also be wiredly connected to the shared AP 20. The CPU 11 may be called a "processor."

[0025] Next, an example of the hardware configuration of the shared AP 20 will be described with reference to the block diagram of Fig. 3. As shown in Fig. 3, the shared AP 20 includes a CPU 21, a ROM 22, a RAM 23, a wireless communication module 24, and a wireless communication module 25.

[0026] The CPU 21 is an integrated circuit capable of executing various programs and controls the overall operation of the shared AP 20. The ROM 22 is, for example, a non-volatile semiconductor memory that stores programs and control data for controlling the shared AP 20. The RAM 23 is, for example, a volatile semiconductor memory that is used as a work area for the CPU 21. The wireless communication module 24 is a circuit used to transmit and receive data, etc., to and from the terminal device 30 via an antenna. The wireless communication module 25 is a circuit used to transmit and receive data, etc., to and from the sharing AP 10 via wired signals.

[0027] The shared AP 20 may have other hardware configurations. For example, the shared AP 20 may be connected to the sharing AP 10 by wire. The antenna may be built into the shared AP 20 or may be externally connected. The CPU 21 may be called a "processor."

[0028] Next, an example of the hardware configuration of the terminal device 30 included in the information communication system 1 according to the first embodiment will be described with reference to the block diagram of Fig. 4. As shown in Fig. 4, the terminal device 30 includes a CPU 31, a ROM 32, a RAM 33, a wireless communication module 34, a display 35, and a storage 36.

[0029] The CPU 31 is an integrated circuit capable of executing various programs and controls the overall operation of the terminal device 30. The ROM 32 is, for example, a non-volatile semiconductor memory and stores programs and control data for controlling the terminal device 30. The RAM 33 is, for example, a volatile semiconductor memory and is used as a work area for the CPU 31. The wireless communication module 34 is configured to be able to send and receive wireless signals via an antenna and is a circuit used for sending and receiving data to and from the shared AP 20. The display 35 displays, for example, a graphical user interface (GUI) corresponding to application software. The storage 36 is a non-volatile storage device and stores, for example, system software for the terminal device 30.

[0030] The terminal device 30 may have other hardware configurations. For example, if the terminal device 30 is an IoT (Internet of Things) terminal or the like, the display 35 may be omitted from the terminal device 30. The display 35 may function as an input interface for the terminal device 30. The antenna may be built into the terminal device 30 or may be externally connected. The CPU 31 may be called a "processor."

[0031] Next, an example of the functional configuration of the sharing AP 10 according to the first embodiment will be described with reference to the block diagram of Fig. 5. As shown in Fig. 5, the sharing AP 10 includes a data processing unit 101, a management unit 102, a frame processing unit 103, and a transmission / reception unit 104. The management unit 102 includes a terminal management unit 1021.

[0032] Data processing unit 101 outputs data input from the network NW side via an LLC layer (not shown) to frame processing unit 103. Data processing unit 101 also outputs data input from frame processing unit 302 to the network NW side via the LLC layer.

[0033] The frame processing unit 103 exchanges management information with the management unit 102, and exchanges data with the data processing unit 301. The frame processing unit 103 distributes the management information and data input from the data processing unit 101 or management unit 102 to the shared AP 20 connected to the affiliated STA under the destination non-AP_MLD. When the frame processing unit 103 is connected to the terminal device 30 via multiple shared APs 20, the frame processing unit 103 may distribute data to the shared APs 20 according to TID (traffic ID).

[0034] The transmitting / receiving unit 104 is connected to the shared AP 20 via a wired or wireless connection. The transmitting / receiving unit 104 transmits data, etc. input by the frame processing unit 103 to the shared AP 20 connected to the transmitting / receiving unit 104. The transmitting / receiving unit 104 transmits data, etc. received from the shared AP 20 connected to the transmitting / receiving unit 104 to the frame processing unit 103. When simultaneously notifying multiple shared APs 20, the transmitting / receiving unit 104 may transmit a beacon signal, etc. by multicast or broadcast.

[0035] The management unit 102 manages the link status and wireless communication with each shared AP 20. The management unit 102 manages the schedule of the R-TWT SP used in the multi-AP connection. For example, the management unit 102 schedules the R-TWT SP for the highest priority low latency data to each shared AP 20 and assigns it to the link configured by each shared AP 20. The management unit 102 can also perform processing to establish a multi-AP connection with the non-AP_MLD of the terminal device 30. The management unit 102 performs other setup processing, such as a TID-link mapping process that allocates links according to TID.

[0036] The terminal management unit 1021 holds priority terminal information (terminal identification information, TID information, information related to the R-TWT SP, etc.) related to priority terminals, and exchanges information about priority terminals managed by other sharing APs 10. A priority terminal is a terminal device 30 for which data communication is prioritized, such as when performing data communication of low-latency traffic. Note that the terminal device 30 may be treated as a priority terminal or a normal terminal depending on the priority of the traffic, for example, by treating the terminal device 30 as a priority terminal only while performing data communication of low-latency traffic, and treating it as a normal terminal when performing data communication other than low-latency traffic.

[0037] Next, the functional configuration of shared AP 20 will be described with reference to the block diagram of Fig. 6. As shown in Fig. 6, shared AP 20 includes a data processing unit 201, a management unit 202, a frame processing unit 203, a frame processing unit 204, a transceiver unit 205, and a transceiver unit 206. Management unit 202 includes a terminal management unit 2021 and a communication control unit 2022.

[0038] The data processing unit 201 inputs the MAC frame input from the frame processing unit 203 to the frame processing unit 204 , and inputs the MAC frame input from the frame processing unit 204 to the frame processing unit 203 .

[0039] Based on the notification from the sharing AP 10, the management unit 202 generates and transmits beacons necessary for multi-AP connection, manages wireless connections between the terminal device 30 and affiliated STAs, and so on.

[0040] The terminal management unit 2021 manages priority terminal information notified by the sharing AP 10 or priority terminal information recognized by the shared AP 20 itself.

[0041] The communication control unit 2022 executes handover processing and processing related to the setup of the R-TWT SP for the terminal device 30. The communication control unit 2022 executes data communication with a priority terminal that has completed handover to its own device as a handover destination, during an R-TWT SP allocation period scheduled from the time the handover is completed until a predetermined time has elapsed.

[0042] The frame processing unit 203 and the frame processing unit 204 each perform processing on a MAC frame, such as generating a MAC frame for input data and extracting data from the input MAC frame.

[0043] The transmitting / receiving unit 205 performs wireless processing on the MAC frame input from the frame processing unit 203 and transmits it to the terminal device 30. The transmitting / receiving unit 205 also receives a wireless signal from the terminal device 30, extracts the MAC frame from the wireless signal, and outputs it to the frame processing unit 203. The transmitting / receiving unit 205 also acquires information from the terminal device 30 itself indicating that the terminal device 30 that is the handover target is a priority terminal in which data communication is prioritized.

[0044] The transmitting / receiving unit 206 performs wireless processing on the MAC frame input from the frame processing unit 204 and transmits it to the sharing AP 10. The transmitting / receiving unit 206 also receives a wireless signal from the sharing AP 10, extracts the MAC frame from the wireless signal, and outputs it to the frame processing unit 204. The transmitting / receiving unit 206 also acquires information from the sharing AP 10 indicating that the terminal device 30 to be handed over is a priority terminal in which data communication is prioritized.

[0045] Next, the functional configuration of terminal device 30 will be described with reference to the block diagram of Fig. 7. As shown in Fig. 7, terminal device 30 includes a data processing unit 301, a frame processing unit 302, a transmission / reception unit 303, and a communication control unit 304. Data processing unit 301, frame processing unit 302, and transmission / reception unit 303 are included in an affiliated STA. Communication control unit 304 is included in a non-AP MLD.

[0046] The data processing unit 301 generates data such as low-delay traffic to be transmitted by the R-TWT function.

[0047] The frame processing unit 302 performs processing on MAC frames. Specifically, for example, it receives low-latency traffic data from the data processing unit 301 and generates a MAC frame including the low-latency traffic data. The frame processing unit 302 receives the MAC frame from the transmitting / receiving unit 303, determines whether it has been received correctly based on the frame check sequence, and if it has been received correctly, extracts data from the MAC frame.

[0048] The transmitting / receiving unit 303 transmits and receives data to and from the shared AP 20. The transmitting / receiving unit 303 notifies the handover source shared AP 20 that the terminal device itself is a priority terminal in which data communication is prioritized.

[0049] The communication control unit 304 executes handover to the handover destination shared AP 20. When the above-described handover is completed, the communication control unit 304 executes data communication with the handover destination shared AP 20 during an R-TWT SP allocation period scheduled from the time when the handover is completed in the handover destination shared AP 20 until a predetermined time has elapsed.

[0050] Next, an example of handover processing in the information communication system 1 according to the first embodiment will be described with reference to the sequence diagram of Fig. 8. Fig. 8 is a sequence diagram showing, in chronological order, processing between a first access point 60 representing the shared AP 20 that is the handover source, a second access point 64 representing the shared AP 20 that is the handover destination, and a priority terminal 62. In the example of Fig. 1, the first access point 60 is the shared AP 20-2, and the second access point 64 is the shared AP 20-4.

[0051] As a premise, in step SA1, it is assumed that the first access point 60 and the priority terminal 62 are performing data communication via the R-TWT SP. It is assumed that a plurality of terminal device groups, each including one or more terminal devices, are set in the link where the R-TWT SP is set, and that a different R-TWT SP allocation period is scheduled for each of the terminal device groups. The schedule is set, for example, by the sharing AP 10 or the shared AP 20. Specific details of the R-TWT SP allocation period will be described later with reference to FIG. 9.

[0052] Furthermore, a general method may be used to set up the R-TWT function. For example, the sharing AP 10 transmits TWT information to each shared AP 20. The TWT information includes information about links (transmission paths) that can use the TWT function. Each shared AP 20 then broadcasts a beacon signal that includes the TWT information. This beacon signal can be received by each of the affiliated STAs #1 to #2 of the terminal device 30. When each affiliated STA #1 to #2 receives the beacon signal, it acquires the TWT information and transmits it to the non-AP_MLD.

[0053] The non-AP_MLD transmits a TWT request to the shared AP 20 based on the received TWT information. The TWT request includes the identifier of the non-AP_MLD and information about links available for multi-AP connection. The sharing AP 10 determines the R-TWT SP setup target based on the TWT request received via the shared AP 20. Then, the sharing AP 10 transmits an R-TWT response to the non-AP_MLD via the shared AP 20. When the non-AP_MLD receives the R-TWT response, the setup of the R-TWT function (TWT agreement setup) is completed.

[0054] In step SA2, the first access point 60 notifies the second access point 64 of priority terminal information. Here, the first access point 60 determines that the terminal device communicating via the R-TWT SP is the priority terminal 62, and notifies the second access point 64 of information on the terminal device 30 communicating with the first access point 60 via the R-TWT function as priority terminal information. As the priority terminal information, for example, terminal identification information and R-TWT SP group information may be notified to the second access point 64.

[0055] Whether a terminal device 30 is a priority terminal or not may be determined by notifying the first access point 60 that it is a priority terminal when the terminal device 30 performs data communication using the R-TWT function. For example, a beacon frame indicating that it is a priority terminal may be transmitted to the first access point 60, or priority terminal information may be notified by transmitting a data frame including information indicating that it is a priority terminal 62 during data communication using the R-TWT SP. Furthermore, when communication is performed between the terminal device 30 and the first access point 60 using an application that generates low-latency traffic, the first access point 60 may determine that the terminal device 30 that executes the traffic generated by the application is a priority terminal 62.

[0056] The method of notifying the second access point 64 of the priority terminal information may be, for example, notifying the second access point 64 via communication between sharing APs 10. Specifically, in the example of Fig. 1, the shared AP 20-2 notifies the connecting sharing AP 10-1 of the priority terminal information, the sharing AP 10-1 notifies the sharing AP 10-2 of the priority terminal information, and the sharing AP 10-2 notifies the shared AP 20-4 of the priority terminal information. Alternatively, the first access point 60 or the priority terminal 62 may notify the second access point 64 of the priority terminal information by broadcasting a beacon frame, action frame, or the like including the priority terminal information.

[0057] In step SA3, the priority terminal 62 transmits a handover request to the second access point 64. Note that the handover request may be transmitted from the first access point 60 to the second access point 64 via the sharing AP 10, as in the method of notifying priority terminal information described above.

[0058] In step SA4, the communication control unit 2022 of the second access point 64 responds to the handover request and performs handover setup for the terminal device 30. Note that the handover setting processing in steps SA3 and SA4 is assumed to be a general handover processing, and therefore detailed description thereof will be omitted here.

[0059] In step SA5, the communication control unit 2022 of the second access point 64 determines a period during which the priority terminal 62 is able to communicate. Here, the R-TWT SP scheduled from the time of handover until a predetermined time has elapsed is determined as the period during which the priority terminal 62 will communicate data. Specifically, the communication control unit 2022 of the second access point 64 may determine, for example, the R-TWT SP scheduled first from the time of handover completion, or the R-TWT SP scheduled next to the R-TWT SP that starts first, as the R-TWT SP scheduled from the time of handover until a predetermined time has elapsed, in other words, as the period during which communication is possible.

[0060] In step SA6, handover of the priority terminal 62 is executed between the first access point 60 and the second access point 64. Here, it is assumed that handover of the priority terminal 62 to the second access point 64 is completed.

[0061] In step SA7, the communication control unit 2022 of the second access point 64 multicasts or broadcasts a trigger frame related to the R-TWT SP, which indicates that the priority terminal 62 is capable of data communication, to one or more terminal devices 30 belonging to its own BSS. The trigger frame includes terminal identification information related to the terminal devices capable of communication via the R-TWT SP, the target link, and information related to the start time, duration, or end time of the assigned R-TWT SP.

[0062] In step SA8, data communication is performed during the allocation period of the R-TWT SP determined in step SA5 between the priority terminal 62 for which handover has been completed and the second access point 64. Note that, when a trigger frame is received by a terminal device other than the priority terminal 62 belonging to the BSS of the second access point 64, if the terminal identification information of the terminal device itself is not included, the terminal device may determine that the allocation period is a transmission suppression period.

[0063] The notification process of the priority terminal information in step SA2 may be performed by the first access point 60 to the second access point 64 before or during the data communication in the R-TWT SP in step SA1.

[0064] 8 assumes a multi-AP connection in which a sharing AP 10 is present, but the R-TWT SP allocation process shown in FIG. 8 can be executed in the same way even if a sharing AP 10 is not present. If a sharing AP 10 is not present, the priority terminal 62 transmits information including the priority terminal information to the second access point 64, and executes the handover process shown in FIG. 8. Also, since a multi-link connection is assumed here, if another link in the priority terminal 62 is already connected to the second access point 64, in the example of FIG. 1, link #2 is already connected to the shared AP 20-4, which is the second access point 64, so the priority terminal information may be transmitted to the second access point 64 using link #2.

[0065] 8 can also be applied to a single-link connection in which the first access point 60, the second access point 64, and the priority terminal 62 each communicate via only one link. When a sharing AP 10 is present in the single-link connection, the priority terminal information and handover request may be transmitted to the second access point 64 via the sharing AP 10, or may be transmitted by the priority terminal 62. On the other hand, when a sharing AP 10 is not present in the single-link connection, the priority terminal information and handover request may be transmitted by the priority terminal 62.

[0066] Next, a first example of data communication of a priority terminal 62 before and after handover between a first access point and a second access point will be described with reference to FIG. 9 . FIG. 9 shows R-TWT SP allocation periods scheduled in time series at each of the first access point 60 and the second access point 64. "SP1," "SP2," and "SP3" are R-TWT SP allocation periods set for different terminal device groups. In other words, a terminal device 30 assigned to "SP1" can basically only perform data communication using the R-TWT function at the timing of "SP1." Furthermore, the R-TWT SP allocation periods "SP1," "SP2," and "SP3" are periodically repeated so that multiple terminal device groups are equally given opportunities to transmit data communication using the R-TWT function. That is, the allocation period of the R-TWT SP is scheduled to be repeated periodically in the order of "SP1", "SP2", "SP3", "SP1", "SP2", and so on.

[0067] Here, it is assumed that the R-TWT SP schedule of the first access point 60 and the R-TWT SP schedule of the second access point 64 are asynchronous, but they may be synchronized. That is, in FIG. 9, the first access point 60 is in an "SP1" allocation period, while the second access point 64 is in an "SP3" allocation period at the same time, and they are asynchronous. The first access point 60 and the second access point 64 may be synchronized so that they are in the "SP1," "SP2," and "SP3" periods at the same time.

[0068] It is assumed that the priority terminal 62 performed data communication using the R-TWT function with the first access point 60, which is the handover source, during a period when the R-TWT SP was "SP1". After that, the priority terminal 62 waited for data communication at the R-TWT SPs of "SP2" and "SP3", and performed handover during the allocation period of "SP1" and "SP2".

[0069] When the priority terminal 62 belongs to the BSS of the second access point 64, which is the handover destination, it executes data communication using the R-TWT function at the timing of the first R-TWT SP allocation period "SP2" from the time the handover is completed at the second access point 64. Thereafter, the priority terminal 62 executes data communication using the R-TWT function during the allocation period "SP1" at the handover source.

[0070] The communication control unit 2022 of the second access point 64 may determine the timing of the R-TWT SP that performed data communication after the handover is completed as the allocation period of the new R-TWT SP for the priority terminal 62. In this case, the terminal management unit 2021 of the second access point 64 manages information related to the allocation period of the new R-TWT SP. In the example of Fig. 9, the priority terminal 62 and the second access point 64 may perform data communication using the R-TWT function during the allocation period of "SP2". The second access point 64 may notify the priority terminal 62 of which R-TWT SP to use for data communication by using an action frame or a trigger frame.

[0071] Next, a second example of data communication of the priority terminal 62 before and after handover between the first access point and the second access point will be described with reference to FIG. 10 . In the example of FIG. 10 , it is assumed that the first R-TWT SP "SP2" after the handover is completed is already reserved by multiple terminal devices belonging to the BBS of the second access point 64, and data communication by other terminal devices cannot be added (a case in which changing the reserved terminal device is prohibited). In this case, the priority terminal 62 may wait for data communication during period 70 of "SP2" and perform data communication using the R-TWT function in the next period, "SP3." Thereafter, the priority terminal 62 and the second access point 64 may perform data communication using the R-TWT function during "SP1," the allocation period scheduled by the first access point 60 before the handover, or may perform data communication using the R-TWT function in the new allocation period, "SP3." As another example of a method for allocating a period during which communication is possible, two consecutive R-TWT SP periods "SP3" and "SP1" may be allocated to the priority terminal 62, as shown in FIG.

[0072] Furthermore, when data communication of the priority terminal 62 is given priority, the second access point 64 may overwrite information about the terminal device that is scheduled to perform data communication in the first R-TWT SP allocation period "SP2" after the completion of the already reserved handover, so that the priority terminal 62 that has handed over can perform data communication using the R-TWT function in the allocation period "SP2".

[0073] The second access point 64 may be set so that a specific R-TWT SP cannot be interrupted. For example, the allocation period "SP2" may be set so that interruption cannot be interrupted, and the other R-TWT SPs "SP1" and "SP3" may be set so that the priority terminal 62 that has handed over can perform data communication using the R-TWT function.

[0074] According to the first embodiment described above, the priority terminal is recognized between the shared APs before and after the handover, and the priority terminal executes data communication in the R-TWT SP allocation period scheduled until a predetermined time has elapsed since the completion of the handover. This ensures a transmission opportunity for the priority terminal, which is a terminal device that executes data communication that should be prioritized, such as low-latency traffic, and reduces delays in data communication due to handover.

[0075] (Second embodiment) The second embodiment differs from the first embodiment in that the allocation period is determined based on the transmission interval from when data communication using the R-TWT function is performed with the first access point 60, which is the source of the handover, until when data communication using the R-TWT function becomes possible with the second access point 64, which is the destination of the handover.

[0076] An example of the functional configuration of the shared AP 20 according to the second embodiment will be described with reference to the block diagram of Fig. 11. In the shared AP 20 according to the second embodiment shown in Fig. 11, the management unit 202 further includes a determination unit 2023, as compared to the shared AP 20 according to the first embodiment shown in Fig. 6.

[0077] The determination unit 2023 determines whether or not the transmission interval from the time when the priority terminal ends data communication by the R-TWT function before handover to the timing corresponding to the period of the R-TWT SP assigned by the handover source in the own device that is the handover destination is equal to or greater than a threshold. If the determination unit 2023 determines that the transmission interval is equal to or greater than the threshold, the communication control unit 2022 executes data communication with the priority terminal that has completed handover, during the allocation period of the first scheduled R-TWT SP or the next scheduled R-TWT SP from the time when the handover is completed.

[0078] Next, an example of determining an allocation period to a priority terminal after completion of handover according to the second embodiment will be described with reference to the flowchart in Fig. 12. In step SB1, the second access point 64 acquires the elapsed time since the start of handover. The elapsed time may be counted by the second access point 64 from the start of handover, or the priority terminal 62 may count the elapsed time and notify the second access point 64 after completion of handover.

[0079] In step SB2, the second access point 64 determines whether the elapsed time acquired in step SB1 is equal to or greater than a threshold value. If the elapsed time is equal to or greater than the threshold value, the process proceeds to step SB3. If the elapsed time is less than the threshold value, the process proceeds to step SB4.

[0080] In step SB3, the second access point 64 sets the R-TWT SP so that data communication can be performed in the first scheduled R-TWT SP or the next R-TWT SP after the handover is completed for the priority terminal 62. This allows the data communication of the priority terminal 62 to be given priority.

[0081] In step SB4, the second access point 64 determines an R-TWT SP with which the priority terminal 62 can perform data communication at a timing that does not exceed a threshold. For example, if the period during which data communication using the R-TWT function with the first access point 60, the handover source, was performed at a timing that does not exceed the threshold, the period of the handover source can be used as is without changing it. Note that the second access point 64 may assign the R-TWT SP with the fewest reservations, or the R-TWT SP with which the number of competing terminals is below a predetermined number, as the R-TWT SP with which the priority terminal 62 will perform data communication at a timing that does not exceed the threshold after the handover of the priority terminal 62 is completed. This allows the priority terminal 62 to select a less busy R-TWT SP to perform data communication, thereby improving traffic efficiency.

[0082] Furthermore, the second access point 64 may acquire the disconnection time of the priority terminal 62 at the handover source from the sharing AP 10 to which it is connected, via the handover source sharing AP 10 connected to the first access point 60, and use the time counted from the disconnection time as the elapsed time. This allows for more accurate calculation of the period during which the priority terminal 62 is unable to communicate.

[0083] According to the second embodiment described above, based on the transmission interval from when data communication by the R-TWT function is performed with the first access point at the handover source until when data communication by the R-TWT function becomes possible with the second access point at the handover destination, if the transmission interval is equal to or greater than a threshold, data communication related to low latency traffic with the priority terminal is performed in the R-TWT SP scheduled first after the handover is completed or in the allocation period of the next R-TWT SP. This makes it possible to satisfy the demand for low latency traffic while ensuring fairness with data communication opportunities for other terminal devices, for example, without giving too much priority to data communication for a terminal device that frequently repeats handovers.

[0084] In the above embodiments, the CPU 11 of the sharing AP 10, the CPU 21 of the shared AP 20, and the CPU 31 of the terminal device 30 may each be other circuits. For example, the sharing AP 10, the shared AP 20, and the terminal device 30 may each include an MPU (micro processing unit) instead of a CPU. Each of the processes described in each embodiment may be realized by dedicated hardware. The processes of the sharing AP 10, the shared AP 20, and the terminal device 30 may be a mixture of processes executed by software and processes executed by hardware, or may be only one of them.

[0085] In the above embodiments, the flowcharts used to explain the operations are merely examples. The order of the processes of the operations described in the embodiments may be changed as far as possible, and other processes may be added. For example, the multi-link and multi-AP connection setup methods and R-TWT communication methods described in the above embodiments are merely examples. A wireless communication standard other than the IEEE 802.11 standard may be used as the wireless communication standard.

[0086] The present invention is not limited to the above-described embodiments, and various modifications can be made in the implementation stage without departing from the spirit of the invention. Furthermore, the embodiments may be implemented in appropriate combinations, in which case the combined effects can be obtained. Furthermore, the above-described embodiments include various inventions, and various inventions can be extracted by combining selected elements from the disclosed elements. For example, if the problem can be solved and the desired effect can be obtained even if some elements are deleted from all elements shown in the embodiments, the configuration from which these elements are deleted can be extracted as an invention.

[0087] 1... Information communication system 10, 10-1, 10-2... Sharing AP 11, 21, 31... CPU 12, 22, 32... ROM 13, 23, 33... RAM 14, 24, 25, 34... Wireless communication module 15... Wired communication module 20, 20-1 to 4... Shared AP 30... Terminal device 35... Display 36... Storage 60... First access point 62... Priority terminal 64... Second access point 70... Period 101, 201, 301... Data processing unit 102, 202... Management unit 103, 203, 204, 302... Frame processing unit 104, 205, 206, 303... Transmitting / receiving unit 304, 2022... Communication control unit 1021, 2021... Terminal management unit 2023... Determination unit

Claims

1. An acquisition unit that acquires information indicating that a terminal device to be handed over is a priority terminal to which data communication is prioritized; a control unit that executes the data communication during an allocation period of an R-TWT SP (restricted-target wake time service period) scheduled until a predetermined time elapses from the time when the handover to the own device as a handover destination is completed, for the priority terminal that has completed the handover to the own device; An access point comprising:

2. The R-TWT SP is allocated for each of a plurality of different terminal device groups and is scheduled periodically. The control unit executes the data communication with the priority terminal during an allocation period for each set period starting from the allocation period in which the data communication was executed. The access point according to claim 1.

3. The R-TWT SP is allocated for each of a plurality of different terminal device groups and is scheduled periodically. When the first R-TWT SP scheduled from the time when the handover is completed is an R-TWT SP that prohibits changing the terminal device that communicates by R-TWT, the control unit uses the next R-TWT SP as the allocation period and executes the data communication with the priority terminal. The access point according to claim 1.

4. An acquisition unit that acquires information indicating that a terminal device to be handed over is a priority terminal to which data communication is prioritized; a determination unit that determines whether a transmission interval from the start of the handover of the priority terminal to a timing corresponding to a period of an R-TWT SP (restricted-target wake time service period) allocated at the handover source in the own device as the handover destination is equal to or greater than a threshold value; a control unit that executes the data communication during an allocation period of an R-TWT SP scheduled until a predetermined time elapses from the time when the handover is completed, for the priority terminal that has completed the handover, when it is determined that the transmission interval is equal to or greater than the threshold value; An access point comprising:

5. The control unit according to claim 4, wherein when the transmission interval is less than the threshold value, the control unit performs the data communication with the priority terminal during the allocation period of the R-TWT SP scheduled at the handover source.

6. The access point according to claim 1, wherein the allocation period is the R-TWT SP scheduled first after the handover is completed or the R-TWT SP scheduled next to the first-starting R-TWT SP.

7. A terminal device comprising: a notification unit that notifies a first access point at a handover source that the own device is a priority terminal for which data communication is prioritized; and a control unit that performs the data communication with the second access point during an allocation period of an R-TWT SP (restricted-target wake time service period) scheduled until a predetermined time has elapsed from the time when the handover to the second access point at the handover destination is completed.

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