Terminal device, communication device, and communication method

Abstract

A terminal device according to the present disclosure is provided with a control unit. The control unit notifies a first communication device that is connected thereto of condition information related to a switching condition for switching the connection destination from the first communication device to a second communication device. After satisfying the switching condition and upon receiving a completion notification notifying that the switching of the connection destination from the first communication device to the second communication device has been completed, the control unit transmits data to the second communication device.

Description

Terminal device, communication device, and communication method

[0001] The present disclosure relates to a terminal device, a communication device, and a communication method.

[0002] In recent years, there has been an increase in environments in which multiple access points (hereinafter also referred to as APs) are installed in various use cases such as homes, offices, and factories, and high-speed, highly reliable Wi-Fi (registered trademark) networks are constructed.

[0003] In this way, in an environment where multiple APs are installed, a terminal device (a station or a station terminal, hereinafter also referred to as an STA) can continue good communication by, for example, selecting an AP with good communication quality and performing handover processing.

[0004] As an example of this handover process, IEEE802.11be / Multi-Link Operation is considering the operation of seamless handover using a defined MLD (Multi-Link Device) entity.

[0005] This seamless handover allows the STA to receive data (downlink (DL) data) from the AP without interruption (seamlessly).

[0006] Duncan Ho et al., “Seamless Roaming details,” IEEE 802.11-24 / 52r0, January 12, 2024.

[0007] As described above, in the conventional handover process, DL communication from the AP to the STA can be performed seamlessly without interruption, whereas UL communication from the STA to the AP is interrupted for a period of time.

[0008] If the STA holds UL data during this period when UL communication is interrupted, the STA must transmit the UL data after this period ends, which causes a problem of a large delay in transmitting the UL data.

[0009] In XR (Extended Reality), which includes virtual reality (VR) and augmented reality (AR), gaze information and posture information of a user using an STA are periodically collected. Images are generated using this gaze information and posture information and transmitted to the STA.

[0010] Therefore, XR requires low-latency, highly reliable, and high-throughput DL communications. Also, low-latency and highly reliable UL communications are required. Also, use cases such as the Industrial IoT (Internet of Things) require low-latency UL communications.

[0011] Thus, in an environment where multiple APs are installed, there is a demand for handover processing (AP switching processing) that can further reduce the increase in the amount of delay in UL communication.

[0012] Therefore, the present disclosure proposes a terminal device, a communication device, and a communication method that can further reduce an increase in the amount of delay in UL communication in an AP switching process.

[0013] It should be noted that the above problem or object is merely one of multiple problems or objects that can be solved or achieved by multiple embodiments disclosed in this specification.

[0014] The terminal device of the present disclosure includes a control unit that notifies a connected first communication device of condition information related to a switching condition for switching a connection destination from the first communication device to a second communication device, and when the control unit receives a completion notification indicating that the switching of the connection destination from the first communication device to the second communication device has been completed after the switching condition is satisfied, transmits data to the second communication device.

[0015] 1 is a diagram illustrating an example of a communication system according to an embodiment of the present disclosure. FIG. 1 is a diagram illustrating an example of STA initiated roaming in which a first STA determines whether to switch APs. FIG. 2 is a diagram illustrating an example of an AP switching process according to an embodiment of the present disclosure. FIG. 3 is a block diagram illustrating an example of a configuration of an AP (communication device) according to an embodiment of the present disclosure. FIG. 4 is a block diagram illustrating an example of a configuration of a STA (terminal device) according to an embodiment of the present disclosure. FIG. 5 is a diagram illustrating an example of a first AP switching process according to an embodiment of the present disclosure. FIG. 6 is a flowchart illustrating an example of a flow of an STA-side switching process according to an embodiment of the present disclosure. FIG. 7 is a flowchart illustrating an example of an AP-side switching process according to an embodiment of the present disclosure. FIG. 8 is a diagram illustrating an example of a second AP switching process according to an embodiment of the present disclosure. FIG. 9 is a flowchart illustrating another example of a flow of an STA-side switching process according to an embodiment of the present disclosure. FIG. 10 is a flowchart illustrating another example of a flow of an AP-side switching process according to an embodiment of the present disclosure. FIG. 11 is a diagram illustrating an example of a third AP switching process according to an embodiment of the present disclosure. FIG. 12 is a flowchart illustrating another example of a flow of an STA-side switching process according to an embodiment of the present disclosure. FIG. 13 is a diagram illustrating an example of a MAC frame format. FIG. 14 is a diagram illustrating an example of a frame configuration of a condition signal according to an embodiment of the present disclosure. FIG. 15 is a diagram illustrating another example of a frame configuration of a condition signal according to an embodiment of the present disclosure. FIG. 16 is a diagram illustrating an example of an HT Control field format. FIG. 17 is a diagram illustrating an example of an A-Control field format. FIG. 18 is a diagram illustrating an example of a Control subfield format. FIG. 19 is a diagram illustrating an example of a Sequence Control field format. Fig. 1 is a block diagram showing an example of the hardware configuration of a computer that executes the above-mentioned series of processes by a program. Fig. 2 is a block diagram showing an example of the schematic configuration of a smartphone to which the present technology is applied. Fig. 3 is a block diagram showing an example of the schematic configuration of an in-vehicle device to which the present technology is applied. Fig. 4 is a block diagram showing an example of the schematic configuration of wireless to which the present technology is applied.

[0016] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0017] In this specification and drawings, similar components of the embodiments may be distinguished by adding at least one different alphabet and / or number after the same reference numeral. However, if there is no need to particularly distinguish between the similar components, only the same reference numeral will be used.

[0018] One or more embodiments (including examples, modifications, and application examples) described below can be implemented independently. However, at least a portion of the embodiments described below may be implemented in appropriate combination with at least a portion of another embodiment. These embodiments may include novel features that are different from each other. Therefore, these embodiments may contribute to solving different purposes or problems and may produce different effects from each other.

[0019] <<1. Introduction>> <1-1. Related Technology> <1-1-1. Multi-Link Communication> For example, IEEE 802.11be, which corresponds to Wi-Fi 7, adopts Multi-Link Operation (MLO). MLO is a wireless communication method that uses multiple links.

[0020] A device that supports MLO is called a Multi-Link Device (MLD). An MLD can link multiple wireless interfaces and establish multiple links. An MLD divides the Medium Access Control (MAC) sublayer into multiple (e.g., two) functional groups. For example, an MLD divides the MAC sublayer into two functional groups: Upper-MAC (U-MAC) and Lower-MAC (L-MAC).

[0021] U-MAC is a common processing unit for all interfaces. U-MAC has, for example, a function for managing sequence numbers. L-MAC is an independent processing unit for each interface. L-MAC has, for example, a function for performing channel access that operates independently for each interface.

[0022] MLD can achieve low latency, highly reliable transmission, and high throughput by utilizing multiple links.

[0023] <1-1-2. AP Switching> As described above, there are an increasing number of environments in which multiple APs are deployed within homes and factories. In such environments, there are AP switching techniques that allow a STA to switch the AP to which it connects. This AP switching technique is used, for example, when a STA connects to an AP with good channel conditions. Furthermore, when a large number of STAs are connected to an AP, the AP can be used to perform traffic distribution (load balancing).

[0024] In this AP switching, the STA that wants to switch first disconnects (disassociates) from the currently connected AP and then connects (associates) to the new AP. During this AP switching, a communication cutoff period occurs during which the STA cannot communicate with the AP.

[0025] Hereinafter, the STA that wishes to perform AP switching may be referred to as a Roaming STA (or simply as a STA). Furthermore, the AP that is connected to the Roaming STA before the AP switching may be referred to as a Source AP (or a source AP). The AP that connects to the Roaming STA after the AP switching, i.e., the new destination AP, may be referred to as a Target AP (or a destination AP).

[0026] To solve this problem of communication interruption periods, methods for seamlessly switching APs have been proposed. For example, the above-mentioned non-patent document proposes two switching methods. One is a method that utilizes Single Link Operation (SLO), and the other is a method that utilizes Dual Links.

[0027] (Method Using SLO) For example, in the method using SLO, the Source AP transmits all DL traffic buffered before Data Path Switching is performed to the Roaming STA before the AP is switched.

[0028] The Source AP then transmits a Roaming Announcement Response (RAR) to the Roaming STA, disassociating it from the new Target AP.

[0029] In this method, all DL traffic buffered in the source AP is transmitted to the roaming STA before the AP is switched, so that the AP is switched without interrupting the DL traffic.

[0030] On the other hand, the DL traffic buffered in the Target AP is not transmitted to the Roaming STA until the Source AP transmits the RAR to the Roaming STA, which increases the delay time of this DL traffic.

[0031] In addition, with this method, the Roaming STA cannot transmit UL traffic from the time it requests AP switching, specifically, from the time it transmits a Roaming Announcement Indicator (RAI) to the Source AP until the time the Source AP transmits an RAR. As described above, with this method, a communication interruption period occurs in the transmission of UL traffic (UL communication), and the transmission delay of the UL traffic may increase.

[0032] (Method Using Dual Links) For example, in a method using Dual Links, when Data Path Switching is performed during AP switching processing, a Roaming STA connects to both the Source AP and the Target AP by MLO. The Roaming STA connects to both the Source AP and the Target AP via different links.

[0033] This allows the Roaming STA to receive, from the Source AP, DL traffic buffered in the Source AP before Data Path Switching is performed, and also allows the Roaming STA to receive, from the Target AP, DL traffic buffered in the Target AP after Data Path Switching is performed.

[0034] The Source AP transmits all buffered DL traffic and then performs Disassociation with the Roaming STA.

[0035] In this way, in a method utilizing Dual Links, MLO allows a Roaming STA to connect to both the Source AP and the Target AP, thereby further shortening the delay time of DL traffic buffered in the Target AP.

[0036] However, even with this method, the Roaming STA cannot transmit UL traffic from the time it requests an AP switch, specifically, for example, from the time it sends a Roaming Announcement Indicator (RAI) to the Source AP until the Source AP sends an RAR.

[0037] As described above, in the conventional AP switching method, a communication interruption period occurs in the transmission of UL traffic (UL communication), and there is a risk of an increase in the transmission delay of the UL traffic.

[0038] <1-1-3. Virtual Reality (VR)> In VR, a user's gaze information and posture information are collected. For example, a terminal device (corresponding to an STR) periodically collects the user's gaze information and posture information and transmits it to, for example, an application server via an AP. The application server generates an image based on the gaze information and posture information collected from the STA and transmits it to the STA via the AP.

[0039] VR requires the transmission of high-quality video without stuttering. Therefore, DL communication, which transmits video, requires low latency, high reliability, and high throughput. UL communication, which transmits information about the user, such as their gaze and posture, also requires low latency and high reliability.

[0040] In addition, in use cases such as the Industrial IoT (Internet of Things), applications are required to collect information in real time from terminal devices (STAs) located in a wide area, and therefore, in such use cases, low latency is required for wide-area communication and UL communication.

[0041] In order to achieve high throughput and wide-area communication, one method is to arrange multiple APs in a home or factory where STAs, which are IoT terminals, are arranged. By arranging multiple APs, each STA can communicate by switching between APs depending on the channel condition and the number of STAs connected to the AP.

[0042] As described above, in communications that require high throughput, high reliability, and low latency, a method of switching between multiple APs to perform communication is known. However, there is a risk that the latency of UL communication will increase when switching between multiple APs.

[0043] For example, the AP switching method using Dual Links described above can reduce the transmission delay of DL traffic during AP switching, while the AP switching method using SLO can increase the transmission delay of DL traffic but can perform AP switching without interrupting DL communication.

[0044] However, the AP switching method using Dual Links and the AP switching method using SLO described above result in interruption of UL communication.

[0045] Therefore, depending on the timing at which UL traffic occurs in the roaming STA, the delay time of the UL traffic may increase. For example, if AP switching is initiated while UL traffic is buffered in the roaming STA, the transmission delay of this UL traffic may become large. This point will be explained using Figures 1 and 2.

[0046] Fig. 1 is a diagram illustrating an example of a communication system according to an embodiment of the present disclosure. The communication system illustrated in Fig. 1 includes a plurality of APs 100 (a first AP 100A and a second AP 100B in Fig. 1), a plurality of STAs 200 (first to third STAs 200A to 200C in Fig. 1), and a controller 300.

[0047] For example, a second STA 200B, which is a smartphone, is located within the communication range of a first AP 100A and communicates with the first AP 100A. A third STA 200C, which is a head mounted display (HMD), is located within the communication range of the second AP 100B and communicates with the second AP 100B.

[0048] A first STA 200A, which is an HMD, is located within the communication range of a first AP 100A and a second AP 100B. The first STA 200A is communicating with the second AP 100B. The first STA 200A switches the AP to which it connects from the second AP 100B to the first AP 100A.

[0049] The HMD is used to provide, for example, VR services, and therefore the first STA 200A, which is the HMD, is required to have low latency, high reliability, and high throughput in DL communication, as well as low latency and high reliability in UL communication.

[0050] The first STA 200A that switches the AP 100 is not limited to an HMD. The first STA 200A may be any device that requires low latency, such as an industrial IoT device.

[0051] Also, in FIG. 1 , the number of APs 100 is two, but the number of APs 100 is not limited to this. The number of APs 100 may be three or more. Furthermore, the number of STAs 200 is not limited to three. The number of STAs 200 may be two or less, or may be four or more. Furthermore, the control device 300 may be part of the AP 100. In other words, the AP 100 may have the functions of the control device 300.

[0052] Furthermore, backhaul communication connecting the APs 100 with each other and connecting the APs 100 with the control device 300 may be wired communication or wireless communication. Furthermore, the APs 100 and the STAs 200 may or may not be MLDs.

[0053] 2 is a diagram showing an example of the flow of AP switching processing of the first STA 200 A. In FIG. 2, the first STA 200 A (Roaming STA) switches from the second AP 100 B (Source AP) to the first AP 100 A (Target AP).

[0054] First, at time t01, UL traffic is generated in the first STA 200A. Then, at time t02, the first STA 200A transmits a Roaming Request to the second AP 100B. The Roaming Request is a request signal for requesting an AP switch.

[0055] When the second AP 100B correctly receives the Roaming Request from the first STA 200A, that is, when the second AP 100B successfully receives the Roaming Request (for example, from time t02), AP switching is initiated.

[0056] When AP switching is initiated, there is a possibility that UL traffic may not be properly transmitted to upper layers, so UL communication is interrupted from the time t02 when AP switching is initiated until the time when AP switching is completed (time t05 in FIG. 2 ).

[0057] Therefore, AP switching is initiated in a state where the UL traffic data generated at time t01 is buffered in the first STA 200A.

[0058] The second AP 100B that has received the Roaming Request transmits the Roaming Request to the controller 300. When the AP switching process (not shown) between the second AP 100B and the first AP 100A is completed, the second AP 100B receives a Roaming Response from the controller 300.

[0059] The second AP 100B, which has received the Roaming Response, transmits the Roaming Response to the first STA 200A at time t04. At time t05, when the first STA 200A has completed receiving the Roaming Response, AP switching is completed. At the same time, the interruption of UL communication is ended, and UL communication is resumed.

[0060] At time t06 after the AP switching is completed, the first STA 200A transmits the UL traffic data that was generated at time t01 and buffered to the first AP 100A.

[0061] Assume that the delay amount (required delay) required for UL traffic is T0. In this case, UL traffic generated at time t01 is required to be transmitted by time t03, which is the time when the required delay T0 has elapsed from time t01.

[0062] However, since time t03 is within the UL communication blackout period, the first STA 200A cannot transmit UL traffic by time t03. The UL traffic generated at time t01 is transmitted at time t06 when the UL communication blackout period ends.

[0063] The UL traffic generated immediately before the AP switching may experience a delay from time t01 to time t06, i.e., a delay longer than the UL communication interruption period. In this way, the amount of delay of the UL traffic generated immediately before the AP switching increases, and there is a risk that the first STA 200A may not be able to meet the required delay.

[0064] Similarly, if UL traffic occurs during the UL communication cutoff period, the delay of this UL traffic increases, and there is a risk that the required delay cannot be met.

[0065] As such, depending on the timing of AP switching, there is a risk of a large delay in UL communication.

[0066] 2 illustrates an example of STA-initiated roaming in which the first STA 200A determines whether to switch APs. The determination of whether to switch APs may be made by an AP (e.g., the second AP 100B, which is the Source AP). That is, AP-initiated roaming may be performed.

[0067] In the case of AP-initiated roaming, the second AP 100B transmits a Roaming Request. In this case, as in the case of STA-initiated roaming, there is a risk of a large delay in UL communication. Furthermore, in the case of AP-initiated roaming, there is a possibility that AP switching will be performed at a timing unexpected by the first STA 200A.

[0068] <1-1-5. Overview of Proposed Technology> In the communication system according to an embodiment of the present disclosure, a first STA 200A (an example of a terminal device) sets a switching condition for AP switching. The first STA 200A notifies a second AP 100B (an example of a first communication device) of condition information regarding the switching condition.

[0069] 3 is a diagram illustrating an example of an AP switching process according to an embodiment of the present disclosure, in which a first STA 200A (Roaming STA) switches from a second AP 100B (Source AP) to the first AP 100A (Target AP, an example of a second communication device).

[0070] First, at time t11, the first STA 200A transmits a Roaming Condition Request to the second AP 100B. The Roaming Condition Request is an example of a signal including condition information related to an AP switching condition. The switching condition will be described in detail later.

[0071] Next, when UL traffic is generated at time t12, the first STA 200A transmits this UL traffic to the second AP 100B at time t13 and receives a response signal (an Ack signal in FIG. 3 ). This UL traffic is, for example, a signal that satisfies the switching condition.

[0072] Furthermore, a UL communication cutoff period starts from time t14 when the reception of this response signal (Ack signal / Response signal) is completed. That is, the first STA 200A stops transmitting UL traffic after time t14 when the first STA 200A transmits the UL traffic.

[0073] In this embodiment, the first STA 200A stops transmitting UL traffic after satisfying the switching condition. As shown in FIG. 3 , the first STA 200A transmits UL traffic that satisfies the switching condition, which triggers AP switching. In this case, the first STA 200A stops UL transmission after satisfying the switching condition, i.e., after transmitting UL traffic that satisfies the switching condition, when it receives a response signal corresponding to the traffic.

[0074] Upon receiving UL traffic that satisfies this switching condition, the second AP 100B transmits a Roaming Request to the control device 300 at time t15. When the AP switching process (not shown) between the second AP 100B and the first AP 100A is completed, the second AP 100B receives a Roaming Response from the control device 300. Note that the first AP 100A may also receive a Roaming Response from the control device 300.

[0075] The second AP 100B, which has received the Roaming Response, transmits the Roaming Response to the first STA 200A. The Roaming Response is an example of a completion notification that notifies that switching of the connection destination from the second AP 100B to the first AP 100A has been completed. Note that the first AP 100A may also transmit the Roaming Response to the first STA 200A.

[0076] At time t17 when the first STA 200A completes receiving the Roaming Response, the AP switching ends. At the same time, the cutoff of UL communication ends, and UL communication resumes.

[0077] When UL traffic occurs at time t18 after the AP switching is completed, the first STA 200A transmits this UL traffic (an example of data) to the first AP 100A (an example of a second communication device) at time t19.

[0078] In this way, the first STA 200A notifies the second AP 100B to which it is connected of condition information (for example, a Roaming Condition Request) relating to the switching condition for switching the connection destination from the second AP 100B to the first AP 100A.

[0079] Furthermore, after the first STA 200A satisfies the switching conditions, when the first STA 200A receives a completion notification (e.g., a Roaming Response) from the second AP 100B notifying that the switching of the connection destination to the first AP 100A has been completed, the first STA 200A transmits data to the first AP 100A.

[0080] That is, in the communication system according to this embodiment, switching information regarding AP switching conditions is shared between the STA 200 and the AP 100. This allows the first STA 200A to avoid AP switching occurring at unexpected times. For example, the first STA 200A can request the second AP 100B to perform AP switching at a desired timing, such as a timing when UL traffic is unlikely to occur.

[0081] 4 is a block diagram showing a configuration example of an AP 100 (communication device) according to an embodiment of the present disclosure. The AP 100 includes a wireless communication unit 110, a backhaul communication unit 120, a storage unit 130, and a control unit 140.

[0082] (Wireless Communication Unit 110) The wireless communication unit 110 is a communication unit that performs wireless communication with other wireless communication devices (e.g., the STA 200). The wireless communication unit 110 performs communication with the STA 200 in accordance with a wireless LAN (Local Area Network) standard such as Wi-Fi.

[0083] The wireless communication unit 110 includes a common MAC (Media Access Control) processing unit 111, individual MAC processing units 112A and 112B, signal processing units 113A and 113B, RF (Radio Frequency) units 114A and 114B, RF switches 115A and 115B, antennas 118A_1, 118A_2, 118B_1, and 118B_2, and a communication control unit 116.

[0084] 4 is an example, and is not limited to this. The wireless communication unit 110 may include all or some of the common MAC processing unit 111, the individual MAC processing unit 112, the signal processing unit 113, the RF unit 114, the RF switch 115, the antenna 118, and the communication control unit 116.

[0085] Hereinafter, the individual MAC processing unit 112A, signal processing unit 113A, RF unit 114A, and RF switch 115A will be collectively referred to as a first processing unit 117A. Furthermore, the individual MAC processing unit 112B, signal processing unit 113B, RF unit 114B, and RF switch 115B will be collectively referred to as a second processing unit 117B. Furthermore, when there is no need to distinguish between the first processing unit 117A and the second processing unit 117B, they will simply be referred to as a processing unit 117. Furthermore, the processing unit 117 may include all or some of the individual MAC processing unit 112, signal processing unit 113, RF unit 114, and RF switch 115.

[0086] 4 includes two processing units 117. That is, the AP 100 is an MLD that can be connected via two different links.

[0087] Although the number of links to which the AP 100 can be connected is two in this example, the number of links to which the AP 100 can be connected may be three or more. In this case, the AP 100 has a processing unit 117 equal to the number of links to which the AP 100 can be connected.

[0088] Furthermore, the AP 100 is not limited to the MLD. That is, the number of links that the AP 100 can connect to may be one. In this case, the AP 100 includes one processing unit 117.

[0089] Here, the operations of the first processing unit 117A and the second processing unit 117B are the same, so here, the first processing unit 117A will be described, and a description of the second processing unit 117B will be omitted.

[0090] (Common MAC Processing Unit 111) The common MAC processing unit 111 processes data. For example, the common MAC processing unit 111 performs at least a part of media access control (MAC) processing.

[0091] During transmission, the common MAC processing unit 111 performs sequence management of the control information and management information received from the data and communication control unit 116, and performs encryption processing etc. to generate a data unit. During reception, the common MAC processing unit 111 performs decryption processing, and then performs a retransmission request operation and reorder processing.

[0092] This processing is also collectively referred to as common data processing (Upper MAC (U-MAC) processing). Note that the control device 300 may execute at least a part of the common data processing. When the control device 300 always executes the common data processing, the common MAC processing unit 111 (a processing unit that performs common data processing) may be omitted.

[0093] (Individual MAC Processing Unit 112A) The individual MAC processing unit 112A performs at least a part of the MAC processing for media access control. The individual MAC processing unit 112A executes all of the MAC processing except for the processing performed by the common MAC processing unit 111.

[0094] The individual MAC processing unit 112A receives data (e.g., data units) that have been encrypted and have sequence numbers added from the common MAC processing unit 111, and performs the following processing (individual data processing, described below) on the received data.

[0095] During transmission, the individual MAC processing unit 112A adds a MAC header and an error detection code to the encrypted packet to generate a data frame. The individual MAC processing unit 112A also performs a process of concatenating multiple data frames. During reception, the individual MAC processing unit 112A performs a process of deconcatenating the MAC header of the received data frame and performing error detection. The individual MAC processing unit 112A also performs a channel access operation based on carrier sense.

[0096] These processes are collectively referred to as individual data processing (Lower MAC (L-MAC) processing). Note that even when the control device 300 executes at least a part of the common data processing, the individual data processing is executed by the individual MAC processing unit 112A, i.e., the AP 100.

[0097] Furthermore, as shown in FIG. 4, when the AP 100 is an MLD, that is, when the AP 100 is connected to a plurality of links, the common MAC processing unit 111 and the individual MAC processing unit 112A can be configured as separate processing units.

[0098] On the other hand, when the AP 100 is connected to one link, the wireless communication unit 110 may be provided with one processing unit (for example, a MAC processing unit) that combines the common MAC processing unit 111 and the individual MAC processing unit 112A.

[0099] (Signal Processing Unit 113A) The signal processing unit 113A executes processing at the physical layer (PHY). During transmission, the signal processing unit 113A performs encoding, interleaving, modulation, etc. on a data frame, adds a physical header, and generates a symbol stream.

[0100] Upon reception, the signal processing unit 113A analyzes the physical header, and performs demodulation, deinterleaving, decoding, etc. on the symbol stream to generate a data frame. The signal processing unit 113A also estimates complex channel characteristics and performs spatial separation processing as necessary.

[0101] (RF Unit 114A) The RF unit 114A includes a transmitting RF unit (Tx RF) and a receiving RF unit (Rx RF), both of which are not shown. The transmitting RF unit performs digital-to-analog signal conversion, filtering, up-conversion using a local oscillator (not shown), and phase control on the symbol stream to generate a transmission signal.

[0102] The receiving RF section performs down-conversion using a local oscillator (not shown), filtering, and analog-to-digital signal conversion on the received signal to generate a symbol stream.

[0103] (RF Switch 115A) The RF switch 115A switches between transmission and reception. For example, the RF switch 115A switches between the RF section for transmission and the RF section for reception, which is connected to the antennas 118A_1 and 118A_2.

[0104] 4, the number of antennas 118A_1 and 118A_2 connected to the RF switch 115A is two, but the number of antennas is not limited to two. The number of antennas connected to the RF switch 115A may be one or three or more.

[0105] (Communication control unit 116) The communication control unit 116 controls the operation of each unit of the wireless communication unit 110 and the transmission of information between each unit. The communication control unit 116 also controls the transfer of control information and management information to be notified to the STA 200 to the common MAC processing unit 111.

[0106] The function that executes the above-mentioned common data processing (common MAC processing unit 111) is also referred to as an "AP MLD Entity." Furthermore, the functions from that of executing individual data processing to that of amplifying signals (individual MAC processing unit 112A, signal processing unit 113A, and RF unit 114A) are also referred to as an "AP Entity (APx)." The AP 100 may have multiple AP Entities that belong to an AP MLD Entity.

[0107] For example, when the AP 100 functions as a Roaming AP MLD Entity, the AP 100 performs common data processing in the AP MLD Entity for other APs 100. In other words, the AP MLD Entity can function as a Roaming AP MLD Entity.

[0108] Here, the Roaming AP MLD Entity uniformly manages the connection relationships between the APs 100 and the STAs 200 to which it belongs. Therefore, the APs 100 (for example, the first AP 100A and the second AP 100B) that belong to the Roaming AP MLD Entity can omit the reconnection process / reauthentication process with the first STA 200A when performing handover process (AP switching process).

[0109] 4, the wireless communication unit 110 is implemented in the AP 100 as a single integrated circuit (IC), but the configuration of the wireless communication unit 110 is not limited to this. For example, the wireless communication unit 110 may be configured with multiple ICs or individual components. For example, the RF unit 114A, the RF switch 115A, and the antennas 118A_1 and 118A_2 may be implemented in the AP 100 as ICs or individual components separate from the other components of the wireless communication unit 110.

[0110] (Backhaul communication unit 120) The backhaul communication unit 120 is a communication unit that communicates with other APs 100, routers (not shown), and the control device 300. The backhaul communication unit 120 communicates between a backhaul network and a fronthaul network (a network between the AP 100 and the STA 200).

[0111] The backhaul communication unit 120 can communicate with other APs 100, routers, and the control device 300 via wired connections using optical fibers, Ethernet (registered trademark) cables, etc. Alternatively, the backhaul communication unit 120 may communicate wirelessly with these devices.

[0112] The backhaul communication unit 120 decodes packets acquired via the backhaul link and outputs them to the wireless communication unit 110 via the control unit 140. The packets output to the wireless communication unit 110 may be packets with the IP header left intact (access point mode), or packets with the IP header decoded and removed by the backhaul communication unit 120 (router mode). In this embodiment, the AP 100 exchanges information with other APs 100 (communicates with other APs 100) via the backhaul communication unit 120.

[0113] The control link (the link between the control device 300 and another AP 100 ) may be formed using the wireless communication unit 110 or may be formed using the backhaul communication unit 120 .

[0114] (Storage Unit 130) The storage unit 130 is a data readable / writable storage device such as a dynamic random access memory (DRAM), a static random access memory (SRAM), a flash memory, a hard disk, etc. The storage unit 130 holds information used by the control unit 140 and the wireless communication unit 110.

[0115] The storage unit 130 performs queuing of signals from higher layers, buffering of received signals, etc. The storage unit 130 also stores data when the signal processing unit 113A performs synthesis processing.

[0116] (Control Unit 140) The control unit 140 is a controller that controls each unit of the AP 100. The control unit 140 may perform part of the operations of the communication control unit 116. The communication control unit 116 and the control unit 140 may be configured as a single block.

[0117] The control unit 140 may be realized by a processor such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit).

[0118] In particular, the control unit 140 may be realized by a processor executing various programs stored in a storage device inside the AP 100 using RAM (Random Access Memory) or the like as a working area.

[0119] The control unit 140 may be realized by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). The control unit 140 may also be realized by a GPU (Graphics Processing Unit).

[0120] A CPU, an MPU, an ASIC, an FPGA, and a GPU can all be considered controllers. Note that the control unit 140 may be composed of multiple physically separated objects. For example, the control unit 140 may be composed of multiple semiconductor chips.

[0121] 5 is a block diagram showing an example of the configuration of the STA 200 (terminal device) according to an embodiment of the present disclosure. The STA 200 includes a wireless communication unit 210, a storage unit 220, and a control unit 230.

[0122] (Wireless Communication Unit 210) The wireless communication unit 210 is a communication unit that performs wireless communication with other wireless communication devices (e.g., the AP 100). The wireless communication unit 210 performs communication with the AP 100 in accordance with a wireless LAN (Local Area Network) standard such as Wi-Fi.

[0123] The wireless communication unit 210 includes a common MAC processing unit 211, individual MAC processing units 212A and 212B, signal processing units 213A and 213B, RF (Radio Frequency) units 214A and 214B, RF switches 215A and 215B, antennas 218A_1, 218A_2, 218B_1, and 218B_2, and a communication control unit 216.

[0124] 5 is an example, and is not limited to this. The wireless communication unit 210 may include all or some of the common MAC processing unit 211, the individual MAC processing unit 212, the signal processing unit 213, the RF unit 214, the RF switch 215, the antenna 218, and the communication control unit 216.

[0125] Hereinafter, the individual MAC processing unit 212A, signal processing unit 213A, RF unit 214A, and RF switch 215A will be collectively referred to as first processing unit 217A. Furthermore, the individual MAC processing unit 212B, signal processing unit 213B, RF unit 214B, and RF switch 215B will be collectively referred to as second processing unit 217B. Furthermore, when there is no need to distinguish between the first processing unit 217A and the second processing unit 217B, they will simply be referred to as processing unit 217. Furthermore, the processing unit 217 may include all or some of the individual MAC processing unit 212, signal processing unit 213, RF unit 214, and RF switch 215.

[0126] 5 includes two processing units 217. That is, the STA 200 is an MLD that can be connected via two different links.

[0127] Although the number of links to which STA 200 can connect is two in this example, the number of links to which STA 200 can connect may be three or more. In this case, STA 200 has a processing unit 217 for the number of links to which STA 200 can connect.

[0128] Furthermore, the STA 200 is not limited to the MLD. That is, the number of links to which the STA 200 can connect may be one. In this case, the STA 200 includes one processing unit 217.

[0129] Here, the operations of the first processing unit 217A and the second processing unit 217B are the same, so here, the first processing unit 217A will be described, and a description of the second processing unit 217B will be omitted.

[0130] (Common MAC Processing Unit 211) The common MAC processing unit 211 processes data. For example, the common MAC processing unit 211 performs at least a part of MAC processing for media access control (MAC).

[0131] The common MAC processing unit 211 executes common data processing (U-MAC processing) in the same manner as the common MAC processing unit 111 of the AP 100. The common MAC processing unit 211 executes data processing common to the first processing unit 217A and the second processing unit 217B, for example.

[0132] (Individual MAC processing unit 212A) The individual MAC processing unit 212A performs at least a part of the MAC processing for media access control. The individual MAC processing unit 212A performs all MAC processing except for the processing performed by the common MAC processing unit 211. The individual MAC processing unit 212A performs individual data processing (L-MAC processing) in the same way as the individual MAC processing unit 112A of the AP 100.

[0133] Also, as shown in FIG. 5, when the STA 200 is an MLD, that is, when the STA 200 is connected to a plurality of links, the common MAC processing unit 211 and the individual MAC processing unit 212A can be configured as separate processing units.

[0134] On the other hand, when the STA 200 is connected to one link, the wireless communication unit 210 may be provided with one processing unit (for example, a MAC processing unit) that combines the common MAC processing unit 211 and the individual MAC processing unit 212A.

[0135] (Signal Processing Unit 213A) The signal processing unit 213A executes processing at the physical layer (PHY). During transmission, the signal processing unit 213A performs encoding, interleaving, modulation, etc. on a data frame, adds a physical header, and generates a symbol stream.

[0136] Upon reception, the signal processing unit 213A analyzes the physical header, and performs demodulation, deinterleaving, decoding, etc. on the symbol stream to generate a data frame. The signal processing unit 213A also estimates complex channel characteristics and performs spatial separation processing as necessary.

[0137] (RF Unit 214A) The RF unit 214A includes a transmitting RF unit (Tx RF) and a receiving RF unit (Rx RF), both of which are not shown. The transmitting RF unit performs digital-to-analog signal conversion, filtering, up-conversion using a local oscillator (not shown), and phase control on the symbol stream to generate a transmission signal.

[0138] The receiving RF section performs down-conversion using a local oscillator (not shown), filtering, and analog-to-digital signal conversion on the received signal to generate a symbol stream.

[0139] (RF Switch 215A) The RF switch 215A switches between transmission and reception. For example, the RF switch 215A switches between the RF section for transmission and the RF section for reception, which is connected to the antennas 218A_1 and 218A_2.

[0140] 5, the number of antennas 218A_1 and 218A_2 connected to the RF switch 215A is two, but the number of antennas is not limited to two. The number of antennas connected to the RF switch 215A may be one or three or more.

[0141] (Communication control unit 216) The communication control unit 216 controls the operation of each unit of the wireless communication unit 210 and the transmission of information between each unit. The communication control unit 216 also controls the transfer of control information and management information to be notified to the AP 100 to the common MAC processing unit 211.

[0142] 5, the wireless communication unit 210 is implemented in the STA 200 as a single integrated circuit (IC), but the configuration of the wireless communication unit 210 is not limited to this. For example, the wireless communication unit 210 may be configured with multiple ICs or individual components. For example, the RF unit 214A, the RF switch 215A, and the antennas 218A_1 and 218A_2 may be implemented in the STA 200 as ICs or individual components separate from the other components of the wireless communication unit 210.

[0143] (Storage Unit 220) The storage unit 220 is a data readable / writable storage device such as a DRAM, an SRAM, a flash memory, a hard disk, etc. The storage unit 220 holds information used by the control unit 230 and the wireless communication unit 210.

[0144] (Control Unit 230) The control unit 230 is a controller that controls each unit of the STA 200. The control unit 230 may perform part of the operations of the communication control unit 216. The communication control unit 216 and the control unit 230 may be configured as a single block.

[0145] The control unit 230 may be realized by a processor such as a CPU or an MPU, for example. In detail, the control unit 230 may be realized by the processor executing various programs stored in a storage device inside the STA 200 using a RAM or the like as a working area.

[0146] The control unit 230 may be realized by an integrated circuit such as an ASIC or an FPGA. The control unit 230 may also be realized by a GPU.

[0147] A CPU, an MPU, an ASIC, an FPGA, and a GPU can all be considered to be controllers. Note that the control unit 230 may be composed of multiple physically separated objects. For example, the control unit 230 may be composed of multiple semiconductor chips.

[0148] <<3. Example of Processing in Communication System>> Here, an example of processing executed in the communication system according to this embodiment will be described. In the communication system according to this embodiment, for example, several AP switching processes can be executed.

[0149] 3-1. First Example of AP Switching Process First, the AP switching process (hereinafter also referred to as the first AP switching process) when the STA 200 determines whether to switch the AP will be described. That is, the first AP switching process is an example of STA initiated roaming.

[0150] (Outline of First AP Switching Process) Fig. 6 is a diagram illustrating an example of the first AP switching process of the present disclosure. In Fig. 6, a first STA 200A (Roaming STA) switches from a second AP 100B (Source AP) to the first AP 100A (Target AP).

[0151] When the first STA 200A determines to switch APs at time t20, it transmits an AP switching initiation condition request (Roaming Condition Request) frame to the second AP 100B at time t21. This frame includes, for example, condition information related to the AP switching initiation condition (an example of a switching condition). This frame includes, for example, information necessary for a Roaming Request.

[0152] The second AP 100B, which has received the Roaming Condition Request, transmits an AP switching start condition response (Roaming Condition Response) frame to the first STA 200A at time t22.

[0153] In this way, the first STA 200A and the second AP 100B exchange (exchange AP switching start condition communication signals) regarding the AP switching start condition (an example of a switching condition) during the period T1 between time t21 and time t23.

[0154] Next, at time t24, UL traffic is generated. The first STA 200A transmits this UL traffic data to the second AP 100B at time t25 and receives a response signal (an Ack signal in FIG. 3). Here, for example, the data transmitted at time t25 is data that satisfies the AP switching start condition notified at time t22. The UL traffic also includes a management frame and a control frame.

[0155] Furthermore, a UL communication cutoff period starts from time t26 when the reception of this response signal (Ack signal / Response signal) is completed. That is, the first STA 200A stops transmitting UL traffic after time t26 when it transmitted the UL traffic.

[0156] When the second AP 100B confirms that the received data satisfies the AP switching conditions, it transmits a Roaming Request to the control device (controller) 300 at time t27. When the AP switching process (not shown) between the second AP 100B and the first AP 100A is completed, the second AP 100B receives a Roaming Response from the control device 300 at time t28. Note that the first AP 100A may also receive the Roaming Response.

[0157] The second AP 100B, which has received the Roaming Response, transmits the Roaming Response to the first STA 200A at time t29. At time t30, when the first STA 200A has completed receiving the Roaming Response, AP switching is completed. At the same time, the cutoff of UL communication is completed, and UL communication is resumed. Note that there may be cases in which the first AP 100A transmits the Roaming Response to the first STA 200A.

[0158] In this way, the first STA 200A notifies the second AP 100B in advance of the conditions for starting AP switching (AP switching start conditions, hereinafter also simply referred to as start conditions), which allows the second AP 100B to immediately start AP switching when the conditions are met.

[0159] For example, when the first STA 200A transmits data that satisfies this condition, the first STA 200A can start switching APs at a desired timing.

[0160] For example, the desired timing of the first STA 200A may be when the transmission buffer becomes empty. The first STA 200A transmits UL traffic data that satisfies the start condition to the second AP 100B, for example, when the UL traffic buffered in the transmission buffer becomes empty.

[0161] This allows the second AP 100B to start AP switching when the transmission buffer of the first STA 200A becomes empty, in other words, at a timing desired by the first STA 200A. In this way, the second AP 100B can avoid starting AP switching when data (UL traffic) remains in the transmission buffer of the first STA 200A.

[0162] Furthermore, as in the above-described XR use case, for example, UL traffic may occur periodically. In this case, the first STA 200A may predict the timing of the UL traffic occurrence. The first STA 200A may set the start condition using the predicted timing of the UL traffic occurrence.

[0163] For example, the first STA 200A may predict the timing of transmitting UL traffic from the predicted timing of occurrence of UL traffic, and notify the second AP 100B of this predicted transmission timing as the start condition for AP switching.

[0164] In this case, the second AP 100B may start AP switching after the transmission timing (for example, immediately after the transmission timing), for example.

[0165] In addition, the first STA 200A may notify the second AP 100B of information regarding the transmission of UL traffic during the period when UL communication is blocked (information regarding operation during the UL communication blocked period) along with the start condition.

[0166] An example of the operation during the UL communication cutoff period is maintaining the connection (association) between the first STA 200A and the second AP 100B for a certain period. For example, the first STA 200A may notify the second AP 100B of the period for which the connection between the first STA 200A and the second AP 100B will be maintained as information regarding the operation during the UL communication cutoff period.

[0167] Alternatively, an example of the operation during the UL communication cutoff period is that the first AP 100A holds UL data (UL traffic data) from the first STA 200A during the UL communication cutoff period.

[0168] For example, the first STA 200A transmits UL data generated during the UL communication cutoff period to the first AP 100A. For example, when the first AP 100A receives the UL data, it stores the data in a buffer and transmits the data to an upper layer (e.g., a router not shown) when it becomes possible to transmit the UL data to the upper layer.

[0169] An example of the timing at which UL data can be transmitted to a higher layer is when the first AP 100A receives information regarding the security of the connection with the first STA 200A from the second AP 100B and becomes able to decrypt the UL data.

[0170] For example, the information regarding the operation of the first STA 200A during the UL communication cutoff period may include information indicating that UL data will be transmitted to the target AP, information regarding the size of the UL data, and the like.

[0171] In addition, the first STA 200A may obtain information about the Target AP and information about the buffer size of the Target AP (or the size of UL data that can be buffered) from the first AP 100A and / or the second AP 100B.

[0172] In this way, the first STA 200A can transmit UL data even during the UL communication cutoff period by notifying the second AP 100B of the operation to be performed during the UL communication cutoff period.

[0173] As described above, the first STA 200A notifies the second AP 100B in advance of the start conditions for AP switching, so that the second AP 100B can start AP switching when the start conditions are satisfied.

[0174] This allows the first STA 200A to prevent AP switching from being initiated at an unexpected timing, thereby further reducing an increase in delay in UL communication.

[0175] Note that, for example, a capability check may be performed between the first STA 200A and the second AP 100B before the period T1 during which the exchange of the start condition is performed. For example, the first STA 200A notifies the second AP 100B of capability information.

[0176] Capability information is notified using, for example, a beacon frame or a probe request frame / response that includes a capability element used for each version of each standard. In a standard equivalent to IEEE 802.11bn, capability information is expected to be notified using an ultra-high reliability (UHR) capability element.

[0177] 7 is a flowchart illustrating an example of the flow of the STA-side switching process according to an embodiment of the present disclosure. The STA-side switching process illustrated in FIG. 7 is repeatedly executed (e.g., at a predetermined interval) by the first STA 200A while the first STA 200A is connected to the second AP 100B.

[0178] The first STA 200A determines whether to switch APs (step S101). If the APs are not to be switched (step S101; No), the first STA 200A ends the process and continues communication with the second AP 100B.

[0179] On the other hand, when switching APs (step S101; Yes), the first STA 200A determines whether to immediately switch APs (step S102). For example, the first STA 200A determines to immediately switch APs when the communication quality with the second AP 100B falls below a predetermined threshold. For example, the first STA 200A determines to immediately switch APs when the communication environment with the second AP 100B significantly deteriorates.

[0180] When immediate switching of APs is to be performed (step S102; Yes), the first STA 200A notifies the second AP 100B of immediate switching (step S103). For example, the first STA 200A may notify the second AP 100B of immediate switching using a Roaming Condition Request.

[0181] On the other hand, if immediate AP switching is not to be performed (step S102; No), the first STA 200A notifies the second AP 100B of condition information including the start condition (step S104). For example, the first STA 200A notifies the second AP 100B of a Roaming Condition Request including the start condition as condition information.

[0182] Next, the first STA 200A receives a Roaming Condition Response from the second AP 100B and determines a switching condition (step S105). For example, the Roaming Condition Response includes a start condition set by the second AP 100B. The first STA 200A determines the start condition included in the Roaming Condition Response as the start condition for AP switching.

[0183] In this way, the first STA 200A and the second AP 100B exchange the start conditions, so that the first STA 200A and the second AP 100B can negotiate so that the timing of AP switching will be the desired timing.

[0184] The first STA 200A determines whether to immediately switch APs (step S106). For example, the first STA 200A determines to immediately switch APs when the communication quality with the second AP 100B falls below a predetermined threshold. For example, the first STA 200A determines to immediately switch APs when the communication environment with the second AP 100B significantly deteriorates.

[0185] In this way, by determining whether to switch immediately after determining the initiation condition, the first STA 200A can appropriately start switching APs even if the communication environment between the first STA 200A and the second AP 100B suddenly deteriorates.

[0186] If immediate switching of the AP is to be performed (step S106; Yes), the first STA 200A returns to step S103 and notifies the second AP 100B of immediate switching.

[0187] On the other hand, if immediate AP switching is not to be performed (step S106; No), the first STA 200A determines whether or not the start condition is satisfied (step S107). For example, if the start condition is not satisfied, such as if UL data remains in the transmission buffer (step S107; No), the first STA 200A returns to step S106 and determines whether or not immediate AP switching is to be performed.

[0188] On the other hand, if the start condition is satisfied (step S107; Yes), the first STA 200A stops the UL communication (step S108). In this case, the first STA 200A may, for example, transmit data indicating that the start condition is satisfied to the second AP 100B before stopping the UL communication. Alternatively, if the start condition is satisfied after a specified period of time has elapsed, the first STA 200A may stop the UL communication without transmitting UL data to the second AP 100B.

[0189] In addition, when an operation for the UL communication cutoff period during which the UL communication is stopped is set, the first STA 200A may perform the set operation after the UL communication is stopped. Examples of the operation for the UL communication cutoff period include maintaining a connection with the second AP 100B for a certain period of time and transmitting UL data to the first AP 100A.

[0190] Next, the first STA 200A determines whether or not it has received a notification of completion of AP switching from the second AP 100B (step S109). The notification of completion corresponds to, for example, a Roaming Response.

[0191] If the completion notification has not been received (step S109; No), the first STA 200A returns to step S109 and waits for reception of the completion notification.

[0192] On the other hand, if the completion notification has been received (step S109; Yes), the first STA 200A starts UL communication with the first AP 100A, which is the Target AP (step S110), and ends the process.

[0193] (Example of AP-Side Switching Process) Fig. 8 is a flowchart illustrating an example of the flow of AP-side switching process according to an embodiment of the present disclosure. The AP-side switching process illustrated in Fig. 8 is executed by the second AP 100B when condition information (e.g., a Roaming Condition Request) is received from the first STA 200A.

[0194] First, the second AP 100B transmits a response signal (for example, a Roaming Condition Response) to the condition information to the first STA 200A (step S201). This response signal may include a start condition desired by the second AP 100B.

[0195] The start condition included in the response signal may be the same as or different from the start condition included in the condition information. For example, if there is a risk that the communication environment will deteriorate in the future, such as if the number of STAs connecting to the second AP 100B increases, the second AP 100B may transmit a response signal including a start condition that will cause AP switching to be performed more quickly.

[0196] Next, the second AP 100B determines whether or not an immediate request for immediate AP switching has been received (step S202). For example, the second AP 100B determines whether or not the received Roaming Condition Request is a request for immediate switching. Alternatively, the second AP 100B may determine whether or not the immediate switching request has been received after transmitting a response signal.

[0197] If an immediate request has been received (step S202; Yes), the second AP 100B executes the process of step S204. On the other hand, if an immediate request has not been received (step S202; No), the second AP 100B determines whether the start condition is satisfied (step S203).

[0198] For example, the second AP 100B determines that the start condition is satisfied when it receives UL data indicating that the start condition is satisfied from the first STA 200A. Alternatively, the second AP 100B may determine that the start condition is satisfied when a predetermined time has elapsed.

[0199] If the start condition is not satisfied (step S203; No), the second AP 100B returns to step S202 and determines whether or not an immediate request has been received. On the other hand, if the start condition is satisfied (step S203; Yes), the second AP 100B transmits a switching request (e.g., a Roaming Request) to the control device 300 (step S204).

[0200] The second AP 100B performs an AP switching operation (e.g., AP switching processing) with the first AP 100A (step S205). If an operation for a UL communication cutoff period is set between the second AP 100B and the first STA 200A, the second AP 100B performs an operation for the UL communication cutoff period during the AP switching operation. An example of the operation for the UL communication cutoff period is maintaining a connection with the first STA 200A for a certain period.

[0201] The second AP 100B determines whether the AP switching is complete (step S206). For example, the second AP 100B determines whether the AP switching is complete depending on whether a Roaming Response is received from the control device 300.

[0202] If the AP switching is not completed (step S206; No), the second AP 100B returns to step S206 and waits for the completion of the switching. On the other hand, if the AP switching is completed (step S206; Yes), the second AP 100B notifies the first STA 200A of the completion of the switching (for example, a Roaming Response) (step S207), and ends the process.

[0203] As described above, in the first AP switching process, the first STA 200A determines whether to switch APs and transmits condition information (e.g., a Roaming Condition Request) including a start condition to the second AP 100B. This allows the first STA 200A to start AP switching at a desired timing, thereby suppressing an increase in delay in UL communication.

[0204] <3-2. Second AP Switching Process Example> In the first AP switching process described above, the first STA 200A determines whether to switch APs, but the second AP 100B may determine whether to switch APs. That is, the AP switching process in the case of AP initiated roaming will be described as the second AP switching process.

[0205] (Outline of Second AP Switching Process) Fig. 9 is a diagram illustrating an example of the second AP switching process of the present disclosure. In Fig. 9, a first STA 200A (Roaming STA) switches from a second AP 100B (Source AP) to the first AP 100A (Target AP).

[0206] As described above, in the second AP switching process, the second AP 100B makes a determination as to whether to switch APs. In Fig. 9, for example, the second AP 100B makes an AP switching determination at time t31, and transmits a switching request (or a switching notification) requesting AP switching at time t32. For example, the switching request may be a request signal (e.g., a Roaming Condition Query) requesting a start condition.

[0207] In response to this, the first STA 200A transmits condition information (here, Roaming Condition Request) including the start condition to the second AP 100B at time t21. The subsequent processing is the same as the first AP switching processing shown in FIG. 6, and therefore description thereof will be omitted here.

[0208] Thus, in the second AP switching process, the first STA 200A and the second AP 100B exchange information regarding the start condition (an example of a switching condition) (exchange of an AP switching start condition communication signal) during the period T2 between time t32 and time t23.

[0209] In the second AP switching process, similarly to the first AP switching process, a capability check may be performed before the exchange of start conditions (before period T2). The capability check may be performed in the same manner as in the first AP switching process.

[0210] 10 is a flowchart illustrating another example of the flow of the STA-side switching process according to an embodiment of the present disclosure. The STA-side switching process illustrated in FIG. 10 is executed by the first STA 200A upon receiving a switching request (e.g., a Roaming Condition Query) from the second AP 100B.

[0211] The STA-side switching process shown in Fig. 10 differs from the STA-side switching process shown in Fig. 7 in that step S101 for determining AP switching is omitted. The other processes are the same as the STA-side switching process shown in Fig. 7, and therefore will not be described here.

[0212] 11 is a flowchart illustrating another example of the flow of the AP-side switching process according to an embodiment of the present disclosure. The AP-side switching process illustrated in FIG. 11 is repeatedly executed (e.g., at a predetermined interval) by the second AP 100B while the first STA 200A is connected to the second AP 100B.

[0213] 11, the same steps as those in the AP side switching process shown in FIG. 8 are denoted by the same reference numerals, and the description thereof will be omitted.

[0214] 11, the second AP 100B determines whether to perform AP switching (step S301). If AP switching is not to be performed (step S301; No), the second AP 100B ends the process and continues communication with the first STA 200A.

[0215] On the other hand, when switching APs (step S301; Yes), the second AP 100B notifies the first STA 200A of a switching request (for example, a Roaming Condition Query) (step S302).

[0216] Next, the second AP 100B determines whether or not it has received condition information (e.g., a Roaming Condition Request) (step S303). If it has not received the condition information (step S303; No), the second AP 100B returns to step S302, notifies the first STA 200A of a switching request again, and waits for reception of the condition information.

[0217] If the second AP 100B receives the condition information (step S303; Yes), the second AP 100B transmits a response signal (e.g., a Roaming Condition Response) to the first STA 200A (step S201). The subsequent processing is the same as the AP-side switching processing shown in FIG. 8, and therefore description thereof will be omitted.

[0218] As described above, even when the second AP 100B determines the AP switching, the first STA 200A can transmit condition information including the start condition (e.g., a Roaming Condition Request) to the second AP 100B. This allows the first STA 200A to start the AP switching at a desired timing, thereby suppressing an increase in delay in UL communication.

[0219] <3-3. Third AP Switching Process Example> In the first and second AP switching processes described above, the first STA 200A transmits the condition information to the second AP 100B, but the second AP 100B may transmit the condition information to the first STA 200A. Here, another example of AP switching process in the case of AP initiated roaming will be described as a third AP switching process.

[0220] 12 is a diagram illustrating an example of the third AP switching process of the present disclosure. In FIG. 12, a first STA 200A (Roaming STA) switches from a second AP 100B (Source AP) to the first AP 100A (Target AP).

[0221] For example, the second AP 100B makes an AP switching decision at time t31, and transmits information including a start condition (e.g., a Roaming Condition Request) to the first STA 200A at time t41. In the third AP switching process, the information including the start condition (e.g., a Roaming Condition Request) corresponds to switching information.

[0222] At time t42, the first STA 200A transmits a response signal (e.g., a Roaming Condition Response) containing information including a start condition to the second AP 100B. This response signal is a signal (an example of condition information) containing a start condition for starting AP switching.

[0223] In this way, even when the second AP 100B transmits a Roaming Condition Request, the first STA 200A can notify the second AP 100B of a start condition that specifies a desired timing using the response signal. The subsequent processing is the same as the first AP switching processing shown in FIG. 6, and therefore a description thereof will be omitted here.

[0224] In the third AP switching process, the first STA 200A and the second AP 100B exchange information regarding the start condition (an example of a switching condition) (exchange of an AP switching start condition communication signal) during the period T3 between time t41 and time t43 when the transmission of the Roaming Condition Response is completed.

[0225] In the third AP switching process, similarly to the first AP switching process, a capability check may be performed before the exchange of start conditions (before period T3). The capability check may be performed in the same manner as in the first AP switching process.

[0226] 13 is a flowchart illustrating another example of the flow of the STA-side switching process according to an embodiment of the present disclosure. The STA-side switching process illustrated in FIG. 13 is executed by the first STA 200A when the first STA 200A receives information including a start condition (e.g., a Roaming Condition Request) from the second AP 100B.

[0227] In the STA-side switching process shown in FIG. 13, the same processes as those in the STA-side switching process shown in FIG. 10 are denoted by the same reference numerals, and the description thereof will be omitted.

[0228] 13, the first STA 200A, which has determined in step S102 to perform immediate switching, notifies the second AP 100B of a response to the immediate switching (step S401). For example, the first STA 200A transmits a Roaming Condition Response including request information requesting immediate AP switching to the second AP 100B.

[0229] On the other hand, if the first STA 200A determines in step S102 not to perform immediate switching, it notifies the second AP 100B of a response signal (Roaming Condition Response) (step S402) and executes the process of step S106. Note that this response signal includes a start condition for AP switching.

[0230] 14 is a flowchart illustrating another example of the flow of the AP-side switching process according to an embodiment of the present disclosure. The AP-side switching process illustrated in FIG. 14 is repeatedly executed (e.g., at a predetermined interval) by the second AP 100B while the first STA 200A is connected to the second AP 100B.

[0231] 14, the same steps as those in the AP side switching process shown in FIG. 11 are denoted by the same reference numerals, and the description thereof will be omitted.

[0232] The second AP 100B, which has determined in step S301 to perform AP switching, notifies the first STA 200A of information including a start condition (for example, a Roaming Condition Request) (step S501).

[0233] The second AP 100B determines whether or not a response signal (e.g., a Roaming Condition Response) has been received (step S502). If the response signal has not been received (step S502; No), the second AP 100B returns to step S501, notifies the first STA 200A of information including the start condition again, and waits for reception of the response signal.

[0234] If the response signal is received (step S502; Yes), the second AP 100B determines whether or not an immediate request for immediate AP switching has been received (step S503). For example, the second AP 100B determines whether or not the received Roaming Condition Response requests immediate switching. Alternatively, the second AP 100B may determine whether or not an immediate switching request has been received after receiving the response signal.

[0235] If an immediate request has been received (step S503; Yes), the second AP 100B executes the process of step S204. On the other hand, if an immediate request has not been received (step S503; No), the second AP 100B executes the process of step S203.

[0236] As described above, even when the second AP 100B transmits a Roaming Condition Request, the first STA 200A can notify the second AP 100B of the desired timing for AP switching by transmitting a response signal including a start condition. This allows the first STA 200A to start AP switching at the desired timing, thereby suppressing an increase in delay in UL communication.

[0237] Note that, here, an example has been described in which the second AP 100B transmits a Roaming Condition Request when the second AP 100B determines AP switching (AP initiated roaming).

[0238] However, when the first STA 200A determines to switch APs (STA initiated roaming), the second AP 100B may transmit a Roaming Condition Request.

[0239] In this case, for example, when the first STA 200A determines to switch APs, it notifies the second AP 100B of an AP switching request (e.g., Roaming Condition Query). In response to this notification (e.g., Roaming Condition Query), the second AP 100B notifies the first STA 200A of information including a start condition (e.g., Roaming Condition Request). The subsequent processing is the same as the third AP switching processing.

[0240] <<4. Example of Start Condition>> Here, an example of a start condition, which is a condition for starting the AP switching process (switching condition), will be described. Note that, in the following, for simplicity of explanation, it is assumed that the first STA 200A (Roaming STA) notifies the second AP 100B (Source AP) of the start condition, but the second AP 100B may specify the start condition and notify the first STA 200A of the specified start condition.

[0241] The start condition may be at least one of the conditions specified in 1) to 7) below. The first STA 200A may specify at least one of the conditions specified in 1) to 7) below as the start condition and notify the second AP 100B. 1) Designation by traffic 2) Designation by QoS (Quality of Service) information 3) Designation by specific information 4) Designation by timing 5) Designation by Service Period 6) Designation by STA 7) Designation of immediate switching

[0242] 1) Designation by Traffic For example, a method of designating traffic as a start condition can be used. In this case, the first STA 200A notifies the second AP 100B of, for example, information identifying the traffic that triggers the start of AP switching as a start condition. For example, the information identifying the traffic can be the sequence number of the traffic.

[0243] For example, when the second AP 100B receives UL traffic with a sequence number specified in the start condition, it determines that the start condition is satisfied and transmits an AP switching request (for example, a Roaming Request) to the control device 300.

[0244] For example, when the second AP 100B transmits DL traffic with the sequence number specified in the start condition, it may be determined that the start condition is satisfied and transmit an AP switching request (e.g., a Roaming Request) to the control device 300.

[0245] Alternatively, the first STA 200A may specify the amount of traffic data as a start condition instead of or in addition to the information identifying the traffic. For example, the second AP 100B transmits an AP switching request (e.g., a Roaming Request) to the control device 300 upon receiving traffic of the amount of data specified by the first STA 200A.

[0246] The traffic data volume can be specified using, for example, TSPEC (Traffic SPECification) or the like.

[0247] 2) Designation by QoS Information: For example, a method of designating QoS information as a start condition can be used. In this case, the first STA 200A notifies the second AP 100B of, for example, information identifying QoS information that triggers AP switching as a start condition. Examples of information identifying QoS information include Access Category (AC) and Traffic ID (TID).

[0248] For example, when the second AP 100B receives UL traffic of the Access Category specified in the start condition, it determines that the start condition is satisfied and transmits an AP switching request (for example, a Roaming Request) to the control device 300.

[0249] For example, when the second AP 100B transmits DL traffic of the Access Category specified in the start condition, it may be determined that the start condition is satisfied and transmit an AP switching request (e.g., a Roaming Request) to the control device 300.

[0250] 3) Designation by Specific Information For example, a method is used in which specific information (an example of information that designates data) is assigned to traffic as a start condition. Specific information includes, for example, permission information that permits AP switching. An example of permission information is a flag. The first STA 200A notifies the second AP 100B that the inclusion of a flag in a header or the like of the traffic is a condition for starting AP switching.

[0251] For example, when the second AP 100B receives UL traffic including the flag specified in the start condition, it determines that the start condition is met (e.g., AP switching is permitted) and sends an AP switching request (e.g., Roaming Request) to the control device 300.

[0252] For example, when the second AP 100B transmits DL traffic including a flag specified in the start condition, it may be determined that the start condition is satisfied and may transmit an AP switching request (e.g., a Roaming Request) to the control device 300.

[0253] 4) Designation by Timing For example, a method of designating a specific timing as the start condition may be used, in which the first STA 200A notifies the second AP 100B of the timing to start AP switching, for example.

[0254] This timing can be specified, for example, by a time (timer) from a specific starting point (for example, the time when a start condition (for example, a Roaming Condition Request, etc.) is notified).

[0255] Alternatively, this timing may be specified by, for example, a predetermined time. When the start timing of AP switching is specified by a time, for example, synchronization between the first STA 200A and the second AP 100B is required.

[0256] For example, the second AP 100B transmits an AP switching request (for example, a Roaming Request) to the control device 300 at the timing specified by the start condition.

[0257] Note that the timing specified here is not limited to one. Multiple timings may be set as the start condition. Alternatively, timings at a predetermined cycle may be specified as the start condition. When multiple timings are specified, the second AP 100B may notify the first STA 200A of the timing at which the switch was performed.

[0258] In addition, for example, the first STA 200A may specify a period in addition to or instead of the timing. The first STA 200A may specify a period including the timing at which the AP switching is initiated. When specifying a period, the second AP 100B may notify the first STA 200A of the timing at which the switching is performed.

[0259] Alternatively, the first STA 200A may specify a period during which the AP switching process is to be executed. For example, when the AP switching process is started from the timing specified by the first STA 200A, the second AP 100B may determine that the start condition is satisfied if the AP switching process can be completed within the specified period.

[0260] 5) Designation by Service Period: For example, a specific Service Period (SP) may be designated as the timing of the start condition. In this case, the first STA 200A notifies the second AP 100B of a Service Period (e.g., R-TWT (Restricted Target Wake Time) SP) that triggers the start of AP switching.

[0261] For example, the second AP 100B transmits an AP switching request (for example, a Roaming Request) to the control device 300 when the R-TWT SP specified in the start condition ends, assuming that the start condition is satisfied.

[0262] 6) Designation by STA: For example, the start condition may be a method of designating the STA 200 that performs UL transmission and / or the STA 200 that performs DL reception. That is, for example, the start condition may be a method of designating the source of UL traffic (UL data) and / or DL ​​traffic (DL data). In this case, the first STA 200A notifies the second AP 100B of information identifying the STA 200, for example, as the start condition.

[0263] The STA 200 specified in the start condition may be the first STA 200A, or may be a STA 200 other than the first STA 200A.

[0264] For example, when the second AP 100B receives UL traffic from the STA 200 specified in the start condition, the second AP 100B determines that the start condition is satisfied and transmits an AP switching request (for example, a Roaming Request) to the control device 300.

[0265] For example, when the second AP 100B transmits DL traffic to the STA 200 specified in the start condition, the second AP 100B may transmit an AP switching request (e.g., a Roaming Request) to the control device 300, assuming that the start condition is satisfied.

[0266] 7) Specifying Immediate Switching: For example, a method of specifying that the AP switching be performed immediately as a start condition can be given. Here, in this embodiment, "immediate AP switching" means that the AP switching is performed immediately after the transmission of the Roaming Condition Response, regardless of whether the start condition is satisfied.

[0267] In other words, for example, the second AP 100B that receives condition information (for example, Roaming Condition Request) specifying immediate switching as the start condition determines that the start condition is satisfied by receiving this condition information.

[0268] In this case, for example, when this condition information is received, an AP switching request (for example, a Roaming Request) is transmitted to the control device 300 .

[0269] As described above, the start condition can be expressed as a combination of one or more of the above-mentioned conditions.

[0270] For example, the first STA 200A specifies a start condition so that AP switching is initiated at a desired timing. When AP switching is to be initiated when the UL buffer becomes empty, for example, the first STA 200A specifies specific information (for example, a flag) as the start condition.

[0271] The first STA 200A includes specific information (for example, a flag) in the UL traffic to be transmitted when the UL buffer becomes empty, and transmits the UL traffic to the second AP 100B.

[0272] This allows the second AP 100B to start AP switching at the timing when the UL buffer becomes empty.

[0273] Alternatively, if it is known that UL traffic is transmitted at a predetermined period, the first STA 200A may specify the UL traffic and / or the timing as the start condition. Here, the timing specified by the first STA 200A may be, for example, the timing at which a specific UL traffic is transmitted.

[0274] Alternatively, if it is known that UL traffic will not be transmitted for a while (e.g., a predetermined period) after receiving the specific DL traffic, the first STA 200A may specify the DL traffic and / or specify the timing as the start condition. Here, the timing specified by the first STA 200A may be, for example, the timing at which the specific DL traffic is transmitted.

[0275] In this way, the first STA 200A specifies the start condition depending on the timing at which the first STA 200A wants to switch APs, thereby enabling the first STA 200A to switch APs at the desired timing.

[0276] For example, the first STA 200A may specify a start condition by combining the above-described conditions 1) to 7). For example, the first STA 200A may specify a sequence number and timing of UL traffic as start conditions for AP switching.

[0277] In this case, the second AP 100B starts switching APs when, for example, it receives UL traffic with a specified Sequence number or when a specified timing has passed.

[0278] When the start condition specified by the first STA 200A is satisfied, the AP switching process is executed, and the first STA 200A stops transmitting UL traffic. That is, when the start condition is satisfied, the UL communication cutoff period starts.

[0279] Here, it is assumed that the start condition specified by the first STA 200A is transmission and reception of predetermined traffic (e.g., conditions 1) to 3) and 6). In this case, the first STA 200A stops transmission of UL traffic when it transmits or receives a response signal (e.g., an Ack signal) corresponding to the predetermined traffic.

[0280] That is, the first STA 200A starts the UL communication cutoff period by stopping UL communication after confirming that the receiving party (the first STA 200A or the second AP 100B) has received traffic that satisfies the start condition.

[0281] <<5. Example of Frame Configuration in Communication System>> Here, an example of the frame configuration of signals exchanged in the communication system during AP switching processing will be described.

[0282] An example of the frame structure of a signal (hereinafter also referred to as a condition signal) used to exchange start conditions between the first STA 200A and the second AP 100B will be described below. This signal corresponds to, for example, any one of the above-mentioned Roaming Condition Query, Roaming Condition Request, and Roaming Condition Response.

[0283] Fig. 15 is a diagram showing an example of a MAC frame format. Fig. 15 shows the MAC frame format in IEEE 802.11. The Frame Body of the Management frame shown in Fig. 15 is the main body of a signal that includes multiple Elements.

[0284] Fig. 16 is a diagram illustrating an example of a frame configuration of a condition signal according to an embodiment of the present disclosure. An example of the format of an Element included in a Frame Body is shown in the upper diagram of Fig. 16. The upper diagram of Fig. 16 illustrates the Element format in IEEE 802.11.

[0285] As shown in the upper diagram of FIG. 16, the information of an Element is identified by a combination of an Element ID and an Element ID Extension.

[0286] In this embodiment, for example, a new Element ID may be assigned as information for identifying the Roaming Condition Query frame, the Roaming Condition Request frame, and the Roaming Condition Response frame.

[0287] In the present embodiment, the start condition may be assigned to, for example, information in an element format. For example, in the present embodiment, a new Roaming Start Condition element (not shown) may be defined as an example of the format of the condition signal to notify the start condition.

[0288] The Roaming Start Condition element contains a field for information used when a Reassociation Request is made. The Roaming Start Condition element also contains a Roaming Start Condition field that indicates a start condition for starting switching of the AP 100.

[0289] This Roaming Start Condition field is placed in the Information of the Element format, as shown in the middle diagram of FIG.

[0290] As shown in the lower diagram of Fig. 16, the Roaming Start Condition field includes "Query / Request / Response" and "Condition Pattern." After "Condition Pattern," information corresponding to the pattern information stored in "Condition Pattern" is stored as necessary.

[0291] "Query / Request / Response" is, for example, a 2-bit field. Information indicating the type of condition signal is stored in "Query / Request / Response." Examples of the type of condition signal include Roaming Condition Query, Roaming Condition Request, and Roaming Condition Response.

[0292] "Query / Request / Response" stores information indicating whether the signal is a Roaming Condition Query, a Roaming Condition Request, or a Roaming Condition Response.

[0293] The "Condition Pattern" is, for example, an 8-bit field. The "Condition Pattern" sets, for example, the start conditions. More specifically, the "Condition Pattern" sets, in bitmap format, a combination pattern of the start conditions 1) to 7) described above.

[0294] In the example of FIG. 16, a combination pattern of 1) designation by traffic, 2) designation by QoS information, and 4) designation by timing is set as the start condition in "Condition Pattern."

[0295] In this way, multiple start conditions can be combined. Note that in the case of 7) immediate switching, no other conditions are combined. In this way, the start condition can be combined with one or more conditions.

[0296] In the area after "Condition Pattern," specific values ​​(required values) of the start conditions set in "Condition Pattern" can be set.

[0297] For example, suppose the start condition set in "Condition Pattern" is a condition specified by traffic, QoS information, and timing. In this case, after "Condition Pattern," for example, information identifying traffic, information identifying QoS information, and information specifying timing are set.

[0298] In the example of Fig. 16, a traffic sequence number is set after "Condition Pattern" as information for identifying the traffic. Furthermore, a TID is set after the sequence number as information for identifying the QoS information. A time is set after the TID as information for specifying timing.

[0299] Furthermore, after the specific value of the start condition (after Time in FIG. 16), padding is added as necessary.

[0300] The order of the specific values ​​of each condition is not limited to the example of FIG. 16. For example, the time may be set after the sequence number. The order of the specific values ​​of each condition may be determined in advance, for example. The AP 100 and / or the STA 200 may set the specific values ​​in the predetermined order.

[0301] In this way, the AP 100 and / or the STA 200 sets a combination of start conditions using the “Condition Pattern.” This allows the AP 100 and / or the STA 200 to present candidates for start conditions to the communication partner.

[0302] Hereinafter, AP 100 and / or STA 200 that transmits a conditional signal will also be simply referred to as a transmitting device, and AP 100 and / or STA 200 (communication partner) that receives a conditional signal will also be simply referred to as a receiving device.

[0303] For example, even if the condition signal is a Roaming Condition Query, the transmitting device can present candidate start conditions to the receiving device. The transmitting device can present candidate start conditions to the receiving device using, for example, a Roaming Condition Query and / or a Roaming Condition Request.

[0304] When accepting a candidate (request) for a start condition, for example, the transmitting device (receiving device of the Roaming Condition Query and / or Roaming Condition Request) may notify the receiving device (transmitting device of the Roaming Condition Query and / or Roaming Condition Request) of a response (Roaming Condition Response) including the same condition value as the candidate (request) for the start condition.

[0305] If a candidate (request) for a start condition is not accepted, for example, the transmitting device (receiving device of the Roaming Condition Query and / or Roaming Condition Request) may notify the receiving device (transmitting device of the Roaming Condition Query and / or Roaming Condition Request) of a response (Roaming Condition Response) including a condition value different from the candidate (request) for the start condition.

[0306] 17 is a diagram illustrating another example of the frame configuration of the condition signal according to the embodiment of the present disclosure. In FIG. 17, the same configuration as in FIG. 16 will not be described.

[0307] 16, a case has been described in which a combination pattern of one or more conditions is set as the start condition included in the condition signal. In FIG. 17, for example, a plurality of conditions are set individually in the condition signal.

[0308] Specifically, in the condition signal, a subfield corresponding to each condition is assigned. For example, a flag field indicating whether or not each condition is set and, if necessary, a field for setting a specific value for each condition are assigned to the roaming start condition field.

[0309] In Figure 17, subfields corresponding to each condition are shown, for example, subfields for 7) immediate switching designation, 1) designation by traffic, 2) designation by QoS information, 3) designation by specific information, and 4) designation by timing.

[0310] More specifically, in Fig. 17, "Immediate Roaming Request Flag", "Sequence Number Flag", "Sequence Number", "TID Flag", and "TID" are shown as subfields corresponding to each condition. Also, in Fig. 17, "Header Indication Flag", "Time Flag", and "Time" are shown as subfields corresponding to each condition.

[0311] In FIG. 17, the "Immediate Roaming Request Flag", "Sequence Number Flag", "TID Flag", "Header Indication Flag", and "Time Flag" are, for example, 1-bit fields. Also, "Sequence Number" is, for example, a 10-bit field. "Time" is, for example, a 32-bit field.

[0312] The transmitting device turns on the flag of the condition that the transmitting device wants to set. Furthermore, the transmitting device sets specific values ​​(request values) of the condition information as necessary and transmits the condition information.

[0313] When immediate switching is set as the start condition, the "Immediate Roaming Request Flag" is set to On. Meanwhile, in this case, other flags (e.g., "Sequence Number Flag") are set to Off. Alternatively, in this case, other flags may be disabled, i.e., immediate switching may be performed regardless of the values ​​of other flags.

[0314] In addition to a field for setting a start condition (e.g., a Roaming Start Condition field), the Roaming Start Condition element may also include a field for setting information related to AP switching. For example, the information related to AP switching may include information related to operation during a UL communication cutoff period.

[0315] Furthermore, if AP switching is performed again after the AP switching process is completed, AP switching may occur frequently. To avoid this, the STA 200 may be configured not to disassociate from the source AP for a certain period of time after the AP switching process is completed.

[0316] Information regarding the period during which disassociation with the source AP is not performed may be set by a field that sets information regarding AP switching.

[0317] The sizes of the fields shown in FIGS. 16 and 17 are merely examples and are not limited to the examples shown in the figures.

[0318] The transmitting device may present candidate start conditions to the receiving device using, for example, a Roaming Condition Query and / or a Roaming Condition Request.

[0319] When accepting a candidate (request) for a start condition, for example, the transmitting device (receiving device of the Roaming Condition Query and / or Roaming Condition Request) may notify the receiving device (transmitting device of the Roaming Condition Query and / or Roaming Condition Request) of a response (Roaming Condition Response) including the same condition value as the candidate (request) for the start condition.

[0320] If a candidate (request) for a start condition is not accepted, for example, the transmitting device (receiving device of the Roaming Condition Query and / or Roaming Condition Request) may notify the receiving device (transmitting device of the Roaming Condition Query and / or Roaming Condition Request) of a response (Roaming Condition Response) including a condition value different from the candidate (request) for the start condition.

[0321] The frame configurations of the multiple condition signals used in the exchange of the start condition (an example of a switching condition) (exchange of AP switching start condition communication signals) may be different for each condition signal.

[0322] For example, a Roaming Condition Request may have the frame structure shown in FIG. 16, and a Roaming Condition Response, which is a response to this request, may have the frame structure shown in FIG.

[0323] Furthermore, the Roaming Condition Request frame in the first and third AP switching processes is required to include the contents of the Roaming Request, in order to notify the connection partner (the second AP 100B in the first AP switching process, and the first STA 200A in the third AP switching process) that AP switching will be performed.

[0324] Similarly, the Roaming Condition Query frame in the second AP switching process or the like is required to include the contents of the Roaming Request in order to notify the connection partner (the first STA 200A in the second AP switching process) that AP switching will be performed.

[0325] The contents of the Roaming Request include, for example, an SSID (Service Set IDentifier).

[0326] In the above example, the case where information about the start condition is notified using an Element included in the Frame Body of the MAC frame format has been described. The method of notifying information about the start condition is not limited to using this Element. For example, information about the start condition may be notified using the A-Control field.

[0327] The A-Control field can be set using the HT Control field of the MAC Header shown in FIG.

[0328] 18 is a diagram showing an example of the HT Control field format. For example, if B0 and B1 of the HT Control field of the MAC Header are set to "1", the following B2 to B31 become the A-Control field.

[0329] Figure 19 is a diagram showing an example of the A-Control field format. As shown in Figure 19, A-Control is configured to include a Control List. A-Control is padded according to the size of the Control List so that its size becomes 30 bits. The Control List is configured with one or more Control subfields.

[0330] Fig. 20 is a diagram showing an example of a control subfield format. As shown in Fig. 20, the control subfield is identified by a control ID. In standards up to IEEE 802.11be, control IDs 10 and above are reserved.

[0331] For example, information about the start condition may be assigned to the Control information subfield in Fig. 20. For example, the Roaming start condition field shown in Fig. 16 and Fig. 17 may be assigned to the Control information subfield.

[0332] The maximum number of bits (maximum size) of the Control information subfield is 26 bits. Therefore, depending on the size of the information related to the start condition, it can be determined whether the Roaming start condition field is allocated to the Frame Body or the A-Control field.

[0333] 6. Example of Detecting Start Condition When the second AP 100B (Source AP) detects that the start condition is satisfied, it starts the AP switching process. Here, an example of a method for the second AP 100B to detect that the start condition is satisfied using traffic will be described.

[0334] That is, examples of detecting start conditions when the above-mentioned conditions are 1) specified by traffic, 2) specified by QoS (Quality of Service) information, 3) specified by specific information, and 6) specified by STA are described.

[0335] 1) Detection of a start condition specified by traffic For example, the second AP 100B performs AP switching after receiving specified traffic. In this case, the second AP 100B references the MAC Header and determines whether the start condition is satisfied, i.e., whether to perform AP switching.

[0336] 21 is a diagram illustrating an example of a Sequence Control field format. The second AP 100B can check whether the Sequence Number of the traffic is a specified value by, for example, referring to the Sequence Control field included in the MAC Header of the traffic.

[0337] Alternatively, the second AP 100B may detect the designated traffic using the A-Control field. In this case, for example, information for identifying the designated traffic may be set in the A-Control.

[0338] More specifically, an ID for setting information for identifying the designated traffic is newly added as a Control ID in the Control subfield. The first STA 200A stores the information for identifying the traffic in the Control information, for example, using the newly added Control ID.

[0339] The second AP 100B determines whether the traffic is specified in the start condition, in other words, whether the traffic satisfies the start condition, by referring to the control information field of the newly added control ID.

[0340] 2) Detection of the start condition specified by the QoS information For example, the second AP 100B performs AP switching after receiving traffic with the specified QoS information. In this case, the second AP 100B references the MAC Header and determines whether the start condition is met, i.e., whether to perform AP switching.

[0341] The second AP 100B, for example, refers to the TID in the QoS control field included in the MAC Header of the traffic, thereby being able to confirm whether the QoS information of the traffic is a specified value.

[0342] Alternatively, the second AP 100B may detect the QoS information specified using the A-Control field. In this case, for example, information for identifying the specified QoS information may be set in the A-Control.

[0343] More specifically, an ID for setting QoS information is newly added as a Control ID in the Control subfield. The first STA 200A stores the QoS information in the Control information using the newly added Control ID, for example.

[0344] The second AP 100B determines whether the QoS information of the traffic is the QoS information specified in the start condition, in other words, whether the traffic satisfies the start condition, by referring to the control information field of the newly added control ID.

[0345] 3) Detection of the start condition specified by the specific information: For example, the second AP 100B performs AP switching after receiving traffic including the specified specific information. In this case, the second AP 100B references, for example, the MAC Header to determine whether the start condition is satisfied, i.e., whether to perform AP switching.

[0346] For example, the second AP 100B detects specific information specified using the A-Control field. In this case, for example, specific information (e.g., a flag) indicating that the start condition is satisfied may be set in the A-Control.

[0347] More specifically, an ID for setting the specific information is newly added as a Control ID in the Control subfield. The first STA 200A stores the specific information in the Control information using, for example, the newly added Control ID.

[0348] The second AP 100B determines whether the traffic contains the specific information specified in the start condition, in other words, whether the traffic satisfies the start condition, by referring to the control information field of the newly added control ID.

[0349] 6) Detection of Start Condition Specified by STA For example, the second AP 100B performs AP switching after receiving traffic from the specified STA 200. In this case, the second AP 100B references, for example, the MAC Header to determine whether the start condition is satisfied, i.e., whether to perform AP switching.

[0350] The second AP 100B, for example, refers to the Source Address (Transmitting address) in the Address2 field included in the MAC Header of the traffic, thereby enabling the second AP 100B to confirm whether the source of the traffic is the specified STA 200 (for example, the first STA 200A (Roaming STA)).

[0351] As described above, in the communication system according to the present embodiment, the first STA 200A (Roaming STA) and the second AP 100B (Source AP) exchange start conditions for starting the AP switching process. This allows the communication system according to the present disclosure to prevent the AP switching process from being started at an unexpected timing.

[0352] Furthermore, the first STA 200A can transmit traffic that satisfies the start condition to the second AP 100B, thereby causing the AP switching process to be performed at a desired timing, thereby enabling the first STA 200A to further reduce an increase in delay of UL traffic due to the UL communication cutoff period.

[0353] As described above, the technology according to the present embodiment is useful for use cases requiring low latency in UL communication, but the technology may also be applied to other use cases. For example, the technology according to the present embodiment may be applied to conventional UL communication.

[0354] For example, when low latency is not required in UL communication, the first STA 200A (Roaming STA) may transmit a Roaming Condition Request frame requesting immediate switching to the second AP 100B (Source AP). Alternatively, the second AP 100B (Source AP) may transmit a Roaming Condition Request frame requesting immediate switching to the first STA 200A (Roaming STA).

[0355] In this way, by specifying immediate switching as a start condition for the AP switching process, the communication system can realize conventional AP switching. In this way, the communication system according to the present embodiment can perform AP switching that can ensure low latency in UL communication while realizing conventional AP switching.

[0356] <<7. Example of Computer Configuration>> The above-described series of processes can be executed by hardware or software. When the series of processes is executed by software, the program constituting the software is installed from a program recording medium into a computer incorporated in dedicated hardware, a general-purpose personal computer, or the like.

[0357] FIG. 22 is a block diagram showing an example of the hardware configuration of a computer that executes the above-described series of processes by a program.

[0358] A CPU (Central Processing Unit) 801 , a ROM (Read Only Memory) 802 , and a RAM (Random Access Memory) 803 are interconnected by a bus 804 .

[0359] An input / output interface 805 is further connected to the bus 804. An input unit 806 including a keyboard, a mouse, etc., and an output unit 807 including a display, a speaker, etc. are connected to the input / output interface 805. Information related to the present technology, for example, information related to handover (AP switching processing), may be output or displayed from the output unit 807. Information related to the present technology, for example, information related to handover (AP switching processing), may be input from the input unit 806, and confirmation or response to the information output or displayed on the output unit 807 may be input. In addition, a storage unit 808 including a hard disk or nonvolatile memory, a communication unit 809 including a network interface, etc., and a drive 810 that drives removable media 811 are connected to the input / output interface 805.

[0360] In the computer configured as above, the CPU 801 performs the above-described series of processes by, for example, loading a program stored in the storage unit 808 into the RAM 803 via the input / output interface 805 and the bus 804 and executing the program. For example, the CPU 801 may execute processing programs corresponding to the flowcharts of Figures 7, 8, 10, 11, 13, and 14 of the present technology.

[0361] The program executed by the CPU 801 is, for example, recorded on a removable medium 811 or provided via a wired or wireless transmission medium such as a local area network, the Internet, or digital broadcasting, and installed in the storage unit 808.

[0362] The program executed by the computer may be a program that processes in chronological order according to the order described in this specification, or may be a program that processes in parallel or at the required timing, such as when called.

[0363] <<8. Application Examples>> The present technology can be applied to various products. For example, the AP 100 (communication device) in FIG. 4 and the STA 200 (terminal device) and control device 300 in FIG. 5 may be realized as a mobile terminal such as a smartphone, a tablet PC (personal computer), a notebook PC, a portable game terminal, or a digital camera; a fixed terminal such as a television receiver, a projector, a printer, a digital scanner, or a network storage; or an in-vehicle terminal such as a car navigation device or a drive recorder device. Furthermore, the AP 100 (communication device), the STA 200 (terminal device), and the control device 300 may be realized as an M2M (machine-to-machine communication) terminal or an IoT (Internet of Things) terminal such as a smart meter, a vending machine, a remote monitoring device, or a POS (point-of-sale) terminal. The AP 100 (communication device), the STA 200 (terminal device), and the control device 300 may be realized as terminals that require low latency and high reliability, such as XR (Extended Reality / Cross Reality) devices. Furthermore, the AP 100 (communication device), the STA 200 (terminal device), and the control device 300 may be wireless communication modules (for example, integrated circuit modules configured on a single die) mounted on these terminals.

[0364] On the other hand, for example, the AP 100 (communication device), the STA 200 (terminal device), and the control device 300 may be realized as a wireless LAN AP (wireless base station) with or without router functionality. The AP 100 (communication device), the STA 200 (terminal device), and the control device 300 may also be realized as a mobile wireless LAN router. The AP 100 (communication device), the STA 200 (terminal device), and the control device 300 may also be realized as a cellular communication base station and a femtocell. Furthermore, the AP 100 (communication device), the STA 200 (terminal device), and the control device 300 may be wireless communication modules (e.g., integrated circuit modules configured on a single die) mounted on these devices.

[0365] <Configuration example of smartphone> Fig. 23 is a block diagram showing a schematic configuration example of a smartphone 900 to which the present technology is applied. Fig. 23 is described as a configuration example of the smartphone 900, but the present technology is not limited to this, and may be a configuration example of the various devices and functions described above.

[0366] The smartphone 900 includes a processor 901, a memory 902, a storage 903, an external connection interface 904, a camera 906, a sensor 907, a microphone 908, an input device 909, and a display device 910. The smartphone 900 also includes a speaker 911, a wireless communication interface 913, an antenna switch 914, an antenna 915, a bus 917, a battery 918, and an auxiliary controller 919. The smartphone 900 may include all or some of the above.

[0367] The processor 901 may be, for example, a CPU or a SoC (System on Chip), and controls the functions of the application layer and other layers of the smartphone 900.

[0368] The memory 902 includes RAM and ROM, and stores programs and data executed by the processor 901 .

[0369] The storage 903 includes a storage medium such as a semiconductor memory or a hard disk.

[0370] The external connection interface 904 is an interface for connecting an external device such as a memory card or a USB (Universal Serial Bus) device to the smartphone 900 .

[0371] The camera 906 has an imaging element such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS), and generates a captured image.

[0372] The sensor 907 includes a group of sensors such as a positioning sensor, a gyro sensor, a geomagnetic sensor, and an acceleration sensor.

[0373] The microphone 908 converts the sound input to the smartphone 900 into an audio signal.

[0374] The input device 909 includes, for example, a touch sensor that detects a touch on the screen of the display device 910, a keypad, a keyboard, a button, or a switch, and accepts operations or information input from the user.

[0375] The display device 910 has a screen such as a liquid crystal display (LCD), an organic light-emitting diode (OLED) display, or a quantum dot (QD) display, and displays an output image of the smartphone 900.

[0376] The speaker 911 converts the audio signal output from the smartphone 900 into sound.

[0377] The wireless communication interface 913 supports one or more wireless LAN standards such as IEEE802.11a, 11b, 11g, 11ac, 11ad, 11ax, 11ay, 11be, 11bn, and successor standards thereof, and performs wireless communication.

[0378] The wireless communication interface 913 communicates with other devices via a wireless LAN AP in infrastructure mode, and directly with other devices in ad hoc mode or a direct communication mode such as Wi-Fi Direct.

[0379] Unlike ad hoc mode, in Wi-Fi Direct, one of the two devices acts as an AP, but communication is carried out directly between the devices.

[0380] The wireless communication interface 913 typically includes a baseband processor, an RF (Radio Frequency) circuit, a power amplifier, etc. The wireless communication interface 913 may be a one-chip module that integrates a memory that stores a communication control program, a processor that executes the program, and related circuits.

[0381] The wireless communication interface 913 may support other types of wireless communication methods, such as a short-range wireless communication method such as Bluetooth (registered trademark), a proximity wireless communication method such as NFC, or a 3GPP (registered trademark) cellular communication method such as 2G, 3G, 4G, 5G, and 6G, in addition to the wireless LAN method. The wireless communication interface 913 may be a one-chip module that supports multiple wireless communication methods, or may be a combination of modules that support some of the wireless communication methods.

[0382] The antenna switch 914 switches the connection destination of the antenna 915 between multiple circuits included in the wireless communication interface 913 (for example, circuits for different wireless communication methods, or transmission system circuits and reception system circuits).

[0383] The antenna 915 has a single or multiple antenna elements (for example, multiple antenna elements constituting a MIMO (Multiple Input Multiple Output) antenna, or multiple antenna elements constituting an array antenna) and is used for transmitting and receiving radio signals via the wireless communication interface 913.

[0384] 23 , the smartphone 900 may include multiple antennas (for example, an antenna for wireless LAN, an antenna for a close-proximity wireless communication system, and an antenna for a cellular communication system). In this case, the antenna switch 914 may be omitted from the configuration of the smartphone 900.

[0385] The bus 917 connects the processor 901, memory 902, storage 903, external connection interface 904, camera 906, sensor 907, microphone 908, input device 909, display device 910, speaker 911, wireless communication interface 913, and auxiliary controller 919 to each other.

[0386] The battery 918 supplies power to each block of the smartphone 900 shown in FIG. 23 via a power supply line partially indicated by a dashed line in the figure. The auxiliary controller 919 operates the minimum necessary functions of the smartphone 900, for example, in sleep mode. The battery 918 may also be charged via the external connection interface 904. The battery 918 may also have a function that allows information regarding the remaining amount of power, the cumulative power-on time, or the cumulative amount of power supply to be read, and the processor 901, the wireless communication interface 913, or the auxiliary controller 919 may control any of the functions of the above-described embodiments based on the information read from the battery 918.

[0387] In the smartphone 900 shown in Fig. 23 , for example, the communication control unit 116 in Fig. 4 or the communication control unit 216 in Fig. 5 may be implemented in the wireless communication interface 913. For example, processing programs corresponding to the flowcharts in Fig. 7 , 8 , 10 , 11 , 13 , and 14 may be executed in the wireless communication interface 913. Furthermore, at least some of these functions may be implemented in the processor 901 or the auxiliary controller 919.

[0388] The smartphone 900 may operate as a wireless AP (software AP) by the processor 901 executing an AP function at the application level. The wireless communication interface 913 may have a wireless AP function. The processor 901 or the wireless communication interface 913 may have a tethering function that uses a wireless LAN system and a cellular communication system, and may transmit payload data received via the cellular communication system via the wireless LAN system, or may transmit payload data received via the wireless LAN system via the cellular communication system. The smartphone 900 may have a tethering function enabled by user input.

[0389] Furthermore, the smartphone 900 may be provided with a biometric authentication unit (fingerprint authentication, palm shape authentication, voice authentication, blood vessel authentication, face authentication, iris authentication, retina authentication). In this case, a wireless communication interface 913 in which the communication control unit 116 in Fig. 4 or the communication control unit 216 in Fig. 5 is implemented is configured to receive power from the same battery 918 as at least one of the display device 910, the speaker 911, and the biometric authentication unit.

[0390] Furthermore, in the smartphone 900, information is displayed on at least one of the display device 910 and the speaker 911 based on communication with an external device via the wireless communication interface 913. At this time, information related to the present technology, for example, information related to handover (switching processing of the AP 100), may be output from at least one of the display device 910 and the speaker 911. Furthermore, the input device 909 may be configured to input a confirmation or response to the information output from at least one of the display device 910 and the speaker 911.

[0391] <Configuration example of in-vehicle device> Fig. 24 is a block diagram showing an example of a schematic configuration of an in-vehicle device 920 to which the present technology is applied. Fig. 24 is described as an example of the configuration of the in-vehicle device 920, but the configuration is not limited to this and may be an example of the configuration of the various devices and functions described above.

[0392] The in-vehicle device 920 is configured to include a processor 921, a memory 922, a GNSS (Global Navigation Satellite System) module 924, a sensor 925, a data interface 926, a content player 927, and a storage medium interface 928. The in-vehicle device 920 is also configured to include an input device 929, a display device 930, a speaker 931, a wireless communication interface 933, an antenna switch 934, an antenna 935, and a battery 938. The in-vehicle device 920 may be configured to include all or some of the above.

[0393] The processor 921 may be, for example, a CPU or an SoC, and controls the navigation function and other functions of the in-vehicle device 920. The processor 921 can also control the vehicle's driving system, such as the brake, accelerator, or steering, based on information obtained through communication based on the present technology.

[0394] The memory 922 includes RAM and ROM, and stores programs and data executed by the processor 921 .

[0395] The GNSS module 924 measures the position (e.g., latitude, longitude, and altitude) of the in-vehicle device 920 using GNSS signals received from GNSS satellites.

[0396] The sensor 925 includes a group of sensors such as a gyro sensor, a geomagnetic sensor, a millimeter wave radar, a camera (an imaging element such as a CCD or CMOS), and an air pressure sensor.

[0397] The data interface 926 is connected to an in-vehicle network 941 via a terminal (not shown), for example, and acquires data generated on the vehicle side, such as vehicle-side data.

[0398] The content player 927 plays content stored on a storage medium (for example, a CD or DVD) inserted into the storage medium interface 928 or content received via the wireless communication interface 933 .

[0399] The input device 929 includes, for example, a touch sensor, a button, or a switch that detects a touch on the screen of the display device 930, and accepts operations or information input from the user. For example, the input device 929 may be configured to input a confirmation or response to information output from at least one of the display device 930 and the speaker 931.

[0400] The display device 930 has a screen such as an LCD, OLED display, or QD display, and displays images of navigation functions or content being played, as well as information related to the present technology, such as information related to handover (AP switching processing).

[0401] The speaker 931 outputs the navigation function, the audio of the content being played, or information relating to the present technology, for example, information relating to handover (AP switching processing).

[0402] Note that the navigation function and the function of the content player 927 are optional in the in-vehicle device 920. The navigation function and the content player 927 may be removed from the configuration of the in-vehicle device 920.

[0403] The wireless communication interface 933 supports one or more wireless LAN standards such as IEEE802.11a, 11b, 11g, 11n, 11ac, 11ad, 11ax, 11ay, 11be, 11bn, and successor standards thereof, and performs wireless communication.

[0404] The wireless communication interface 933 communicates with other devices via a wireless LAN AP in infrastructure mode, and directly with other devices in ad hoc mode or a direct communication mode such as Wi-Fi Direct.

[0405] Unlike ad hoc mode, in Wi-Fi Direct, one of the two devices acts as an AP, but communication is carried out directly between the devices.

[0406] The wireless communication interface 933 typically includes a baseband processor, an RF circuit, a power amplifier, etc. The wireless communication interface 933 may be a one-chip module that integrates a memory that stores a communication control program, a processor that executes the program, or related circuits.

[0407] The wireless communication interface 933 may support other types of wireless communication methods in addition to the wireless LAN method, such as a short-range wireless communication method such as Bluetooth, a proximity wireless communication method such as NFC, or a 3GPP cellular communication method such as 2G, 3G, 4G, 5G, and 6G. The wireless communication interface 933 may be a one-chip module that supports multiple wireless communication methods, or may be a combination of modules that support some of the wireless communication methods.

[0408] The antenna switch 934 switches the connection destination of the antenna 935 between multiple circuits included in the wireless communication interface 933 (for example, circuits for different wireless communication methods, or transmission system circuits and reception system circuits).

[0409] The antenna 935 has a single or multiple antenna elements (for example, multiple antenna elements constituting a MIMO (Multiple Input Multiple Output) antenna, or multiple antenna elements constituting an array antenna) and is used for transmitting and receiving radio signals via the wireless communication interface 933.

[0410] 24, the in-vehicle device 920 may include a plurality of antennas (for example, an antenna for wireless LAN, an antenna for a close-proximity wireless communication system, and an antenna for a cellular communication system). In this case, the antenna switch 934 may be omitted from the configuration of the in-vehicle device 920.

[0411] The battery 938 supplies power to each block of the in-vehicle device 920 shown in Fig. 24 via a power supply line partially indicated by a dashed line in the figure. The battery 938 may also store power supplied from the vehicle side. Alternatively, the in-vehicle device 920 may not be equipped with a battery and may instead use power supplied from the vehicle side via a voltage regulator or a capacitor.

[0412] In the in-vehicle device 920 shown in Fig. 24 , for example, the communication control unit 116 in Fig. 4 or the communication control unit 216 in Fig. 5 may be implemented in the wireless communication interface 933. For example, processing programs corresponding to the flowcharts in Fig. 7, 8, 10, 11, 13, and 14 may be executed in the wireless communication interface 933. Furthermore, at least some of these functions may be implemented in the processor 921.

[0413] The wireless communication interface 933 may operate as the AP 100 (communication device), the STA 200 (terminal device), and the control device 300 described above, and may provide wireless connection to a terminal owned by a user in the vehicle. For example, the wireless communication interface 933 may connect the in-vehicle device 920 to other peripheral devices, and the in-vehicle device 920 may use CarPlay (registered trademark) or Android Auto (registered trademark). Note that the wireless communication interface 933 may connect the in-vehicle device 920 to other peripheral devices using a short-range wireless communication method, infrastructure mode, or a wireless LAN method using Wi-Fi Direct.

[0414] The in-vehicle device 920 may operate as a wireless AP (software AP) by the processor 921 executing an AP function at the application level. The wireless communication interface 933 may have a wireless AP function. The processor 921 or the wireless communication interface 933 may have a tethering function that uses a wireless LAN system and a cellular communication system, and may transmit payload data received via the cellular communication system via the wireless LAN system, or may transmit payload data received via the wireless LAN system via the cellular communication system. The tethering function of the in-vehicle device 920 may be enabled by user input.

[0415] Furthermore, the present technology may be realized as an in-vehicle system (or vehicle) 940 including one or more blocks of the above-described in-vehicle device 920, an in-vehicle network 941, and a vehicle-side module 942. The vehicle-side module 942 may generate vehicle-side data such as vehicle speed information, engine rotation speed information, information about the vehicle-side battery, or malfunction information, and output the generated data to the in-vehicle network 941, and the processor 921 or the wireless communication interface 933 may control any of the functions of the above-described embodiments based on the vehicle-side data acquired via the in-vehicle network 941.

[0416] <Configuration example of wireless AP> Fig. 25 is a block diagram showing an example of a schematic configuration of a wireless AP 950 to which the present technology is applied. Fig. 25 is described as an example of the configuration of the wireless AP 950, but is not limited to this and may be an example of the configuration of the various devices and functions described above.

[0417] The wireless AP 950 includes a controller 951, a memory 952, an input device 954, a display device 955, a network interface 957, a wireless communication interface 963, an antenna switch 964, and an antenna 965. The wireless AP 950 may include all or some of the above.

[0418] The controller 951 may be, for example, a CPU or a DSP (Digital Signal processor) and operates various functions of the IP (Internet Protocol) layer and higher layers of the wireless AP 950 (e.g., access restriction, routing, encryption, firewall, and log management).

[0419] The memory 952 includes RAM and ROM, and stores programs executed by the controller 951 and various control information (for example, a terminal list, a routing table, an encryption key, security settings, and logs).

[0420] The input device 954 includes, for example, buttons and switches, and receives operations from the user. For example, the input device 954 may input a confirmation or response to information output from the display device 955. Furthermore, the input device 954 may be operated by the user to input switching of the wireless function on / off and switching between the router function and the access point function.

[0421] The display device 955 includes an LED lamp or the like and displays the operation status of the wireless AP 950. The display device 955 may display information related to the present technology, for example, information related to handover (AP switching processing).

[0422] The network interface 957 is a wired communication interface for connecting the wireless AP 950 to a wired communication network 958. The network interface 957 may have multiple connection terminals. The network interface 957 may output payload data included in a wireless signal input from the wireless communication interface 963 as a wired signal, or may receive payload data output as a wireless signal from the wireless communication interface 963 as a wired signal. The network interface 957 may input and output wired signals in parallel with or independently of the wireless communication interface 963 inputting and outputting wireless signals. The wired communication network 958 may be a LAN such as Ethernet (registered trademark), or may be a WAN (Wide Area Network).

[0423] The wireless communication interface 963 supports one or more wireless LAN standards such as IEEE 802.11a, 11b, 11g, 11n, 11ac, 11ad, 11ax, 11ay, 11be, 11bn, and their successor standards, and provides wireless connection to nearby terminals as an AP. When the wireless AP 950 is installed in a cellular communication base station or a femtocell, the wireless communication interface 963 may support other types of wireless communication systems, such as 3GPP cellular communication systems such as 2G, 3G, 4G, 5G, and 6G, in addition to the wireless LAN system. The wireless communication interface 963 may be a one-chip module that supports multiple wireless communication systems, or a combination of modules that support some of the wireless communication systems.

[0424] The wireless communication interface 963 typically includes a baseband processor, an RF circuit, a power amplifier, and the like.

[0425] The wireless communication interface 963 may be a one-chip module that integrates a memory that stores a communication control program, a processor that executes the program, or related circuits.

[0426] The antenna switch 964 switches the connection destination of the antenna 965 between multiple circuits included in the wireless communication interface 963 (for example, circuits for different wireless communication methods, or transmission system circuits and reception system circuits).

[0427] The antenna 965 has a single or multiple antenna elements (for example, multiple antenna elements constituting a MIMO (Multiple Input Multiple Output) antenna, or multiple antenna elements constituting an array antenna) and is used for transmitting and receiving radio signals via the wireless communication interface 963.

[0428] In the wireless AP 950 shown in Fig. 25 , for example, the communication control unit 116 in Fig. 4 or the communication control unit 216 in Fig. 5 may be implemented in the wireless communication interface 963. For example, processing programs corresponding to the flowcharts in Fig. 7, 8, 10, 11, 13, and 14 may be executed in the wireless communication interface 963. Furthermore, at least some of these functions may be implemented in the controller 951.

[0429] The above-described embodiment shows an example for realizing the present technology, and the matters in the embodiment correspond to the matters specifying the invention in the claims. Similarly, the matters specifying the invention in the claims correspond to the matters in the embodiment of the present technology having the same title. However, the present technology is not limited to the embodiment, and can be realized by applying various modifications to the embodiment without departing from the gist of the present technology.

[0430] Furthermore, some or all of the communication devices, terminal devices, and control devices described in the above embodiments may be realized, for example, as semiconductor chips (ICs (Integrated Circuits)) having wireless communication control functions. They may also be realized by a single semiconductor chip equipped with multiple functions, such as a SoC (System on Chip), or by combining multiple semiconductor chips each having a single function, such as a processor. Furthermore, they may be realized by combining multiple SoCs, or by combining a semiconductor chip with a single function and a SoC. They may also be realized by semiconductor chips such as ASICs (Application Specific Integrated Circuits) dedicated to realizing each unit, or by a combination of a general-purpose processor with software or firmware, or by semiconductor chips such as FPGAs (Field Programmable Gate Arrays).

[0431] Furthermore, the processing procedures described in the above embodiments may be regarded as a method having a series of these procedures, or as a program for causing this computer to execute these procedures or a recording medium for storing that program.

[0432] Examples of the recording medium that can be used include a CD (Compact Disc), an MD (MiniDisc), a DVD (Digital Versatile Disc), a memory card, and a Blu-ray (registered trademark) Disc.

[0433] In this specification, a system refers to a collection of multiple components (devices, modules (components), etc.), regardless of whether all the components are contained in the same housing. Therefore, multiple devices housed in separate housings and connected via a network, and a single device housed in a single housing with multiple modules, are both systems.

[0434] Furthermore, the effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0435] The embodiments of the present technology are not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present technology.

[0436] For example, this technology can be configured as cloud computing, in which a single function is shared and processed collaboratively by multiple devices via a network.

[0437] Furthermore, each step described in the above flowchart can be executed by one device, or can be shared and executed by a plurality of devices.

[0438] Furthermore, when one step includes multiple processes, the multiple processes included in that one step can be executed by one device or can be shared and executed by multiple devices.

[0439] <<9. Conclusion>> Although the embodiments of the present disclosure have been described above, the technical scope of the present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the gist of the present disclosure. Furthermore, components of different embodiments and modifications may be combined as appropriate.

[0440] Furthermore, the effects of the embodiments described in this specification are merely examples and are not limiting, and other effects may also be obtained.

[0441] The present technology may also be configured as follows. (1) A terminal device including a control unit that notifies a connected first communication device of condition information related to a switching condition for switching a connection destination from the first communication device to a second communication device, and transmits data to the second communication device upon receiving a completion notification notifying that switching of the connection destination from the first communication device to the second communication device has been completed after the switching condition is satisfied. (2) The terminal device described in (1), in which the control unit stops transmitting the data to the first communication device after the switching condition is satisfied until receiving the completion notification. (3) The terminal device described in (2), in which the control unit stops transmitting the data to the first communication device after receiving from the first communication device a response signal in response to data that satisfies the switching condition until receiving the completion notification. (4) The terminal device described in any one of (1) to (3), in which the control unit notifies the first communication device of the condition information as a switching request to switch the connection destination to the second communication device. (5) The terminal device according to any one of (1) to (3), wherein the control unit notifies the first communication device of the condition information in response to switching information related to the switching of the connection destination, which is notified from the first communication device. (6) The terminal device according to any one of (1) to (5), wherein the control unit receives a response to the condition information from the first communication device after notifying the condition information. (7) The terminal device according to any one of (1) to (6), wherein the control unit transmits the data that satisfies the switching condition to the first communication device. (8) The terminal device according to (7), wherein the switching condition includes information specifying the data and / or information specifying the priority of the data. (9) The terminal device according to (8), wherein the information specifying the data is information specifying a sequence number of the data and / or information related to permission information that permits the switching of the connection destination. (10) The terminal device according to any one of (1) to (9), wherein the switching condition includes information related to timing for switching the connection destination.(11) The terminal device according to (10), wherein the information regarding timing is information regarding a time at which the connection destination is switched or information regarding a Service Period. (12) The terminal device according to any one of (1) to (11), wherein the switching condition includes information regarding a source of the data. (13) The terminal device according to any one of (1) to (12), wherein the control unit sets notification of the condition information as the switching condition. (14) The terminal device according to any one of (1) to (13), wherein the control unit requests the first communication device to switch the connection destination regardless of the switching condition. (15) A communication device comprising: a control unit that acquires, from a connected terminal device, condition information regarding a switching condition for switching a connection destination to another communication device, and switches the connection destination of the terminal device to the other communication device when the switching condition is satisfied. (16) A communication method comprising: notifying a connected first communication device of condition information related to a switching condition for switching a connection destination from the first communication device to a second communication device; and, upon receiving a completion notification notifying that switching of the connection destination from the first communication device to the second communication device has been completed after the switching condition has been satisfied, transmitting data to the second communication device. (17) A communication method comprising: acquiring, from a connected terminal device, condition information related to a switching condition for switching a connection destination to another communication device; and, if the switching condition is satisfied, switching the connection destination of the terminal device to the other communication device.

[0442] 100 AP 110, 210 Wireless communication unit 111, 211 Common MAC processing unit 112A, 112B, 212A, 212B Individual MAC processing unit 113A, 113B, 213A, 213B Signal processing unit 114A, 114B, 214A, 214B RF unit 115A, 115B, 215A, 215B RF switch 116, 216 Communication control unit 120 Backhaul communication unit 130, 220 Storage unit 140, 230 Control unit 200 STA

Claims

1. A terminal device having a control unit that notifies a connected first communication device of condition information regarding switching conditions for switching the connection destination from the first communication device to a second communication device, and, after the switching conditions are satisfied, transmits data to the second communication device upon receiving a completion notification notifying that the switching of the connection destination from the first communication device to the second communication device has been completed.

2. The terminal device according to claim 1, wherein the control unit stops transmitting the data to the first communication device after the switching condition is satisfied until the completion notification is received.

3. The terminal device according to claim 2, wherein the control unit stops transmitting the data to the first communication device after receiving a response signal for data that satisfies the switching condition from the first communication device until receiving the completion notification.

4. The terminal device according to claim 1, wherein the control unit notifies the first communication device of the condition information as a switching request to switch the connection destination to the second communication device.

5. The terminal device according to claim 1, wherein the control unit notifies the condition information in response to switching information regarding switching of the connection destination notified from the first communication device.

6. The terminal device according to claim 1, wherein the control unit receives a response to the condition information from the first communication device after notifying the first communication device of the condition information.

7. The terminal device according to claim 1, wherein the control unit transmits the data that satisfies the switching condition to the first communication device.

8. The terminal device according to claim 7, wherein the switching condition includes information specifying the data and / or information specifying the priority of the data.

9. The terminal device according to claim 8, wherein the information specifying the data is information specifying a sequence number of the data and / or information regarding permission information permitting switching of the connection destination.

10. The terminal device according to claim 1, wherein the switching condition includes information regarding the timing for switching the connection destination.

11. The terminal device according to claim 10, wherein the timing-related information is information about a time when the connection destination is switched or information about a service period.

12. The terminal device according to claim 1, wherein the switching condition includes information about a source of the data.

13. The terminal device according to claim 1, wherein the control unit sets notification of the condition information as the switching condition.

14. The terminal device according to claim 1, wherein the control unit requests the first communication device to switch the connection destination regardless of the switching condition.

15. A communication device having a control unit that acquires condition information regarding switching conditions for switching the connection destination to another communication device from a connected terminal device, and switches the connection destination of the terminal device to the other communication device if the switching conditions are met.

16. A communication method including: notifying a connected first communication device of condition information regarding a switching condition for switching a connection destination from the first communication device to a second communication device; and, after the switching condition is satisfied, transmitting data to the second communication device upon receiving a completion notification notifying that the switching of the connection destination from the first communication device to the second communication device has been completed.

17. A communication method including: acquiring condition information from a connected terminal device regarding switching conditions for switching the connection destination to another communication device; and, if the switching conditions are satisfied, switching the connection destination of the terminal device to the other communication device.

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