Wireless communication device and wireless communication method

Abstract

The present invention transmits data at high speed. This wireless communication device comprises a control unit that performs: control for receiving a roaming request transmitted from a terminal device; control for transmitting, to the terminal device, roaming period data transmission information that is information for transmitting data during a roaming period of the terminal device; control for transmitting, to a base station device, roaming information based on the roaming request; control for receiving data from the terminal device during the roaming period; and control for transmitting the roaming period data transmission information to the base station device.

Description

Wireless Communication Device and Wireless Communication Method

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

[0002] In a wireless communication device that performs roaming, a wireless communication device capable of seamless roaming using a multi-link function has been proposed (for example, see Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2023-107741

[0004] However, in the above prior art, since the terminal device starts uplink communication after waiting for the end of the roaming process, there is a problem that data transmission takes time.

[0005] Therefore, the present disclosure proposes a wireless communication device and a wireless communication method for performing data transmission at high speed.

[0006] The wireless communication device according to the present disclosure includes control for receiving a roaming request transmitted from a terminal device, control for transmitting roaming period data transmission information, which is information for data transmission during the roaming period of the terminal device, to the terminal device, control for transmitting roaming information based on the roaming request to a base station device, control for receiving data from the terminal device during the roaming period, and control for transmitting the roaming period data transmission information to the base station device.

[0007] The wireless communication device according to the present disclosure further includes control for receiving roaming information based on a roaming request from a terminal device transmitted by a base station device, control for receiving roaming period data transmission information, which is information for data transmission during the roaming period of the terminal device, transmitted by the base station device, and control for receiving data from the terminal device transmitted by the base station device.

[0008] The wireless communication device according to the present disclosure further includes control for transmitting a roaming request to a base station device, control for receiving roaming period data transmission information, which is information for data transmission during the roaming period, from the base station device, and control for transmitting data to the base station device based on the roaming period data transmission information.

[0009] This figure shows an example configuration of a communication system according to an embodiment of this disclosure. This figure shows an example of communication processing in a conventional communication system. This figure shows an example configuration of a communication device according to the first embodiment of this disclosure. This figure shows an example configuration of a communication device according to the first embodiment of this disclosure. This figure shows an example of a processing procedure for a base station device according to the first embodiment of this disclosure. This figure shows an example of a processing procedure for a base station device according to the first embodiment of this disclosure. This figure shows an example of a processing procedure for a terminal device according to the first embodiment of this disclosure. This figure shows an example of a roaming request frame according to the first embodiment of this disclosure. This figure shows another an example of communication processing according to the first embodiment of this disclosure. This figure shows an example of communication processing according to the second embodiment of this disclosure. This figure shows an example of communication processing according to the third embodiment of this disclosure. This figure shows an example of communication processing according to the fourth embodiment of this disclosure. This block diagram shows an example of the hardware configuration of a computer that executes the series of processes described above by a program. This block diagram shows a schematic configuration example of a smartphone to which this technology is applied. This block diagram shows a schematic configuration example of an in-vehicle device to which this technology is applied. This block diagram shows an example of a schematic configuration of a wireless access point (AP) to which this technology is applied.

[0010] The embodiments of this disclosure will be described in detail below with reference to the drawings. The description will be in the following order. In each of the following embodiments, the same parts will be denoted by the same reference numerals, and redundant descriptions will be omitted. 1. Background 2. First Embodiment 3. Second Embodiment 4. Third Embodiment 5. Fourth Embodiment 6. Modifications 7. Example of Computer Configuration 8. Application Examples

[0011] (1. Background) (1.1 System Configuration) Multi-link operation (MLO), a wireless communication method using multiple links, is being considered as a way to meet the high transmission speed requirements of 8K transmission and cross-reality (XR). Here, a "link" is a wireless transmission path that can transmit data between two communication devices. When performing MLO, each link is selected from multiple wireless transmission paths that are mutually independent and divided in the frequency domain, for example. For example, channels selected from multiple channels included in one of the frequency bands such as the 2.4 GHz band, 5 GHz band, 6 GHz band, and 920 MHz band are used.

[0012] Devices compatible with MLO are called MLDs (Multi-link Devices). An MLD is a logical entity that contains one or more STAs and has only one SAP (Service Access Point) to the upper layer. An MLD in which each contained STA is an AP is called an AP MLD. An MLD in which each contained STA is a non-AP STA is called a non-AP MLD. To specify that each entity within an MLD is an entity within the MLD, it may be written as an AP belonging to an AP MLD (AP affiliated with AP MLD), or a non-AP STA belonging to a non-AP MLD (non-AP STA affiliated with non-AP MLD).

[0013] In use cases where multiple access points (APs) may be installed, such as in homes or factories, there is a need to provide low-latency, highly reliable communication even when terminals are moving. To achieve this, it is being considered to extend the MLD (Multiple Access Domain) newly defined in IEEE 802.1be for managing multiple APs within the same device, and define an entity that centrally manages APs in different devices (referred to as Roaming MLD in this document, but also known as SMD MLD (Single Mobility Domain MLD) or UFT MLD (Ultra Fast Transition MLD)). Furthermore, the operation of switching the connection destination of terminal devices using this concept is called seamless roaming, and standardization is currently underway. The functionality of the Roaming MLD can be executed on any of the AP devices or on a separate device.

[0014] Figure 1 shows an example configuration of a communication system according to the present disclosure. This system consists of a base station device 10a, a base station device 10b, a terminal device 20, and a roaming MLD 30. The base station device is an example of an AP MLD. The terminal device is an example of a Non-AP MLD. Base station devices 10a and 10b are equipped with multiple APs, and terminal device 20 is equipped with multiple STAs. Base station devices 10a, 10b, 20, and roaming MLD 30 are logical entities, each having a MAC address. The roaming MLD 30 is not mandatory, and base station devices 10a and 10b may cooperate to perform roaming operations. Alternatively, an external control device may perform roaming operations. Base station devices 10a and 10b are connected to a Distribution System (DS) 40.

[0015] The terminal device 20 is within communication range of the base station devices 10a and 10b, and may be connected to and communicating with the base station devices 10a and 10b.

[0016] Furthermore, terminal device 20 may initially be within communication range of base station device 10a, as shown by the dotted line on the left, and then move (roam) to a range where it can communicate with both base station device 10a and base station device 10b. Alternatively, terminal device 20 may initially be within communication range of both base station device 10a and base station device 10b, as shown by the dotted line on the right, and then move to a range where it can communicate with base station device 10b. Alternatively, terminal device 20 may move from left to right, combining these movements. Terminal device 20 connects to base station device 10a and switches its connection destination to base station device 10b as terminal device 20 moves. This enables seamless roaming.

[0017] The roaming MLD 30 manages each base station device, allowing for the sharing of encryption keys (PTKs) among them. However, if PTK sharing is not possible for security reasons, the PTK may be regenerated with the destination base station device without sharing. The terminal device 20 may establish an association with the roaming MLD 30 through the base station device 10a that it initially connects to. The base station devices to be connected to the roaming MLD 30 may also be known in advance, and new base station devices may be connected to the roaming MLD 30 in response to a request from the terminal device 20. Base station devices 10a and 10b are connected by a wired or wireless backhaul. For example, base station devices 10a and 10b can communicate via the backhaul.

[0018] The distribution system 40 is a logical element that provides interconnection between base station devices, and is mainly wired Ethernet (registered trademark), but may also be a Wireless Distribution System (WDS) using a wireless medium. Note that the system configuration in this figure is just an example, and may consist only of base station devices and terminal devices that do not support multilink communication.

[0019] (1.2 Conventional System) Figure 2 is a diagram showing an example of communication processing in a conventional communication system. The diagram is a sequence diagram showing communication processing between terminal device 20, base station device 10a, and base station device 10b. Terminal device 20 connects to base station device 10a and transmits data (step S301). Subsequently, terminal device 20 decides to switch the base station device to connect to (step S302) and sends a roaming request to base station device 10a (step S303). Base station device 10a sends a roaming request to base station device 10b, which is the target base station (step S304). At this time, roaming information, which is context such as information related to data management, is transmitted from base station device 10a to base station device 10b. Furthermore, the DS mapping, which is data path mapping information between the distribution system 40 and terminal device 20, is changed.

[0020] Subsequently, a roaming response is transmitted from the base station device 10b to the base station device 10a (step S305). Next, a roaming response is transmitted from the base station device 10a to the terminal device 20 (step S306). As a result, the terminal device 20 is connected to the base station device 10b and transmits data (step S307).

[0021] (1.3 Problems with Conventional Systems) In the conventional communication system described above, data transfer is prohibited during the roaming process. This is because the parameters transmitted as roaming information may be updated. Also, the original base station equipment 10a may send data to the distribution system 40 after the DS mapping has been changed, which may cause the DS mapping to be returned to the base station equipment 10a. For this reason, as shown in Figure 2, a period of data transmission (uplink communication) suspension is set. As a result, the data communication speed decreases in conventional communication systems.

[0022] (2. First Embodiment) [Configuration of Communication Device] Figure 3 is a diagram showing an example configuration of a communication device according to the first embodiment of the present disclosure. The figure is a block diagram showing an example configuration of the communication device 10. The communication device 10 in the figure corresponds to the base station device 10a and base station device 10b described above. The communication device 10 includes a communication unit 110, a control unit 120, a storage unit 130, a communication unit 140, and antennas 111a and 111b. The communication unit 110 also includes a communication control unit 117, a communication storage unit 118, amplification units 112a and 112b, wireless interface units 113a and 113b, a signal processing unit 114, an individual data processing unit 115, and a common data processing unit 116.

[0023] The amplification units 112a and 112b, the wireless interface units 113a and 113b, the signal processing unit 114, and the individual data processing unit 115 constitute two APs. The signal processing unit 114 and the individual data processing unit 115 are shared between these APs.

[0024] The communication control unit 117 controls the operation of each part and the transmission of information between each part. The communication control unit 117 also controls the transfer of control information and management information to be notified to other communication devices to each data processing unit.

[0025] The communication storage unit 118 holds information used by the communication control unit 117. The communication storage unit 118 also holds data to be transmitted and data that has been received.

[0026] The data processing unit (individual data processing unit 115 and common data processing unit 116) performs sequence management of data held in the communication storage unit 118, control information and management information received from the communication control unit 117, and generates data units by performing encryption processing, etc. The data processing unit (individual data processing unit 115 and common data processing unit 116) also performs channel access operation based on carrier sense, addition of MAC (Media Access Control) header to the data to be transmitted, addition of error detection codes, and concatenation processing of multiple data units. The data processing unit (individual data processing unit 115 and common data processing unit 116) also performs MAC header deconcatenation processing of the received data unit, analysis and error detection, retransmission request operation, data unit decryption processing, and reorder processing. The data processing unit may consist of a plurality of individual data processing units 115 that perform operations necessary for communication in a single frequency band, and a common data processing unit 116 that performs operations common to communication in multiple frequency bands connected to the plurality of individual data processing units 115.

[0027] In this disclosure, the common data processing unit 116 is also referred to as the AP MLD. In particular, in an AP, the common data processing unit 116 may have two parts: a block dedicated to this communication device (AP MLD) and a shared block (roaming MLD) that can communicate with other communication devices. Furthermore, it is not necessary to have a shared data processing unit; in this case, processing is performed by the shared data processing unit of another communication device. Even if a shared data processing unit is present, it may be operated so that processing is performed by the shared data processing unit in another communication device rather than by its own unit. In addition, the AP MLD may consist not only of the common data processing unit 116 but also of a part of the communication control unit 117 and the communication storage unit 118.

[0028] The signal processing unit 114 comprises a transmission signal processing unit and a reception signal processing unit. The transmission signal processing unit performs encoding, interleaving, and modulation of data units, adds a physical header, and generates a symbol stream. The reception signal processing unit analyzes the physical header, performs demodulation, deinterleaving, and decoding of the symbol stream, and generates data units. The reception signal processing unit also performs complex channel characteristic estimation and spatial separation processing as needed. In this invention, this signal processing unit is also referred to as the PHY unit.

[0029] The wireless interface units 113a and 113b each comprise a transmitting wireless interface unit and a receiving wireless interface unit, respectively. The transmitting wireless interface unit performs digital-to-analog signal conversion, filtering, upconversion, and phase control on the symbol stream to generate a transmission signal. The receiving wireless interface unit performs downconversion, filtering, and analog-to-digital signal conversion on the received signal to generate a symbol stream.

[0030] The amplification units 112a and 112b each comprise a transmitting amplification unit and a receiving amplification unit, respectively. The transmitting amplification unit amplifies the signal input from the transmitting wireless interface unit. The receiving amplification unit amplifies the signal input from the antenna. Part of the amplification unit may be an external component of the communication unit. Also, part of the amplification unit may be incorporated into the wireless interface unit. In this invention, the wireless interface unit and the amplification unit are collectively referred to as the RF unit.

[0031] The control unit 120 controls the communication unit 110 and the communication control unit 117. The control unit 120 may also perform some of the operations of the communication control unit 117. Furthermore, the communication control unit 117 and the control unit 120 may be configured as a single block.

[0032] The storage unit 130 holds information used by the control unit 120 and the communication unit 110. It may also perform some of the operations of the communication storage unit 118. The storage unit 130 and the communication storage unit 118 may be configured as a single block.

[0033] A wireless interface unit, an amplifier unit, and an antenna are considered as one set, and two or more sets constitute the components of a communication device, with each set being able to perform wireless communication on its respective link. The communication device 10 in Figure 3 shows an example where two sets of wireless interface units 113, amplifier units 112, and antennas 111 are provided. A storage unit 130 may also be included in the above set. A link is a wireless transmission path that allows data transmission between two communication devices. The links used by each set may also be in different frequency bands. Furthermore, an individual data processing unit and a signal processing unit may be considered as one set, and two or more sets may be connected to a single wireless interface unit.

[0034] The communication unit 140 decodes packets acquired from the backhaul link and passes them to the communication unit 110 via the control unit 120.

[0035] The communication unit 110 can be implemented by one or more LSIs. The configuration of the communication unit 110 is just an example and is not limited thereto. For example, it may be composed of three or more blocks. If it is composed of three or more blocks, some of the blocks may share the same antenna via a frequency division unit. Furthermore, the communication unit 110 may include all of the following: the communication control unit 117, the communication storage unit 118, the amplification units 112a and 112b, the wireless interface units 113a and 113b, the signal processing unit 114, the individual data processing unit 115, and the common data processing unit 116, or it may include some of them.

[0036] Communication control unit 117 and control unit 120 are examples of the "control unit" in this disclosure. The communication control unit 117 and control unit 120 of the base station device 10a perform control to receive a roaming request transmitted from the terminal device 20. The communication control unit 117 and control unit 120 of the base station device 10a further perform control to transmit roaming period data transmission information, which is information for data transmission during the roaming period of the terminal device 20, to the terminal device 20. The communication control unit 117 and control unit 120 of the base station device 10a further perform control to transmit roaming information based on the roaming request to the base station device 10b, and control to receive data from the terminal device 20 during the roaming period. The communication control unit 117 and control unit 120 of the base station device 10a further perform control to transmit roaming period data transmission information to the base station device 10b.

[0037] Furthermore, the communication control unit 117 and control unit 120 of the base station device 10b perform control to receive roaming information based on a roaming request from the terminal device 20 transmitted by the base station device 10a. In addition, the communication control unit 117 and control unit 120 of the base station device 10b further perform control to receive roaming period data transmission information, which is information for data transmission during the roaming period of the terminal device 20 transmitted by the base station device 10a. Furthermore, the communication control unit 117 and control unit 120 of the base station device 10b further perform control to receive data from the terminal device 20 transmitted by the base station device 10b.

[0038] Figure 4 is a diagram showing an example configuration of a communication device according to the first embodiment of this disclosure. Similar to Figure 3, this figure is a block diagram showing an example configuration of the communication device 10. The communication device 10 in this figure is a communication device corresponding to the terminal device 20 described above, and is equivalent to the communication device 10 in Figure 3 with the communication unit 140 omitted.

[0039] The amplification units 112a and 112b, the wireless interface units 113a and 113b, the signal processing unit 114, and the individual data processing unit 115 constitute two STAs. The signal processing unit 114 and the individual data processing unit 115 are shared between these STAs.

[0040] Communication control unit 117 and control unit 120 are examples of the “control unit” of this disclosure. The communication control unit 117 and control unit 120 of the terminal device 20 perform control to transmit a roaming request to the base station device 10a and control to receive roaming period data transmission information, which is information for data transmission during the roaming period, from the base station device 10a. Furthermore, the communication control unit 117 and control unit 120 of the terminal device 20 perform control to transmit data to the base station device 10a based on the roaming period data transmission information.

[0041] [Processing of Base Station Equipment] Figure 5 is a diagram showing an example of the processing procedure for base station equipment according to the first embodiment of this disclosure. The same figure is a flowchart showing an example of the processing procedure for base station equipment 10a.

[0042] First, the base station device 10a exchanges communication environment information (step S101). The base station device 10a transmits its own communication environment information to the base station device 10b and the terminal device 20. The base station device 10a also receives communication environment information from the terminal device 20. The base station device 10a also receives communication environment information from the base station device 10b. As a result, the base station device 10a acquires communication environment information.

[0043] Here, the communication environment information acquired by the base station device 10a includes information about backhaul communication, information about the terminal device 20, information about buffers, information about candidate APs for switching destinations, and capability information indicating whether it supports the operation of the present invention. Information about backhaul communication includes, for example, backhaul delay and congestion status. Information about the terminal device 20 includes, for example, the amount of buffered data and information about the ability to simultaneously transmit and receive on multiple links (the number of links that can transmit and receive simultaneously and whether simultaneous transmission and reception is possible on each link pair (NSTR capability)). Information about buffers includes information about the buffer amount of the base station device 10b.

[0044] Next, the base station device 10a performs connection switching processing for the terminal device 20 (step S102). The base station device 10a receives a roaming request including data transmission request information, which will be described later, from the terminal device 20 and returns a response (ACK). At this time, the response may include roaming period data transmission information. This roaming period data transmission information includes information on the period during which data transmission to its own base station device 10a is permitted and information on the types of data permitted to be transmitted to its own base station device 10a. The information on the period during which data transmission to this base station device 10a is permitted corresponds to, for example, the time until a roaming request is received from the base station device 10b or the expected time. Also, the information on the types of data permitted to be transmitted to the base station device 10a corresponds to, for example, information on the data identifier and information on the data size. Note that the information on the data identifier is, for example, a traffic identifier (Traffic Identifier, hereinafter referred to as TID) for uplink communication. Also, the information on the data size may be determined based on information on the buffer size of the communication environment information of the terminal device 20.

[0045] Also, the base station device 10a determines connection switching based on the information collected from the terminal device 20 and the base station device 10b. Next, the base station device 10a transmits a roaming request to the terminal device 20. This roaming request includes information on the base station device 10b and roaming period data transmission information.

[0046] Next, the base station apparatus 10a transmits roaming information to the base station apparatus 10b (step S103). The roaming information includes information regarding the security of the connection with the terminal device 20 and information regarding data exchange with the terminal device 20. The information regarding the security of the connection with the terminal device 20 includes a group key (GTK) and a cipher key (PTK). Also, the information regarding data exchange with the terminal device 20 includes a SN (Sequence Number), a PN (Packet Number), a TID that can be changed until roaming response generation, and information regarding the SN of the reception schedule. At this time, the change timing of DS mapping may be determined based on the information collected in step S101. Note that when the change of DS mapping is not performed simultaneously with the transmission of the roaming information, the base station apparatus 10a transmits the data received from the terminal device 20 to the distribution system 40 before the start of the change of DS mapping. On the other hand, the base station apparatus 10a performs control not to transmit the data received after the start of the change of DS mapping to the distribution system 40 in the next step S104.

[0047] Next, the base station apparatus 10a determines whether it has received data from the terminal device 20 (step S104). When the base station apparatus 10a has received data from the terminal device 20 (step S104, Yes), the base station apparatus 10a does not transmit the data to the distribution system 40 and transmits the data to the base station apparatus 10b (step S105). At this time, the base station apparatus 10a controls the amount of data to be transferred based on the backhaul information included in the communication environment information, and may notify the terminal device 20 of the amount of data not transferred thereto. Next, the terminal device 20 proceeds to the process of step S106.

[0048] On the other hand, in step S104, when the base station apparatus 10a has not received data from the terminal device 20 (step S104, No), the base station apparatus 10a proceeds to the process of step S106.

[0049] In step S106, base station device 10a receives a roaming response from base station device 10b (step S106). Base station device 10a can include the latest SN and the latest received cache information in its response (ACK) to the roaming response.

[0050] Next, the base station device 10a transmits a roaming response to the terminal device 20 (step S107). This roaming response includes information regarding the management of the data that was transmitted to the base station device 10b (for example, SN and received cache information).

[0051] Figure 6 is a diagram showing an example of the processing procedure for a base station device according to the first embodiment of this disclosure. The same figure is a flowchart showing an example of the processing procedure for the base station device 10b.

[0052] First, the base station device 10b exchanges communication environment information (step S111). The base station device 10b transmits the communication environment information to the base station device 10a. The base station device 10b also receives the communication environment information from the base station device 10a. As a result, the base station device 10b acquires the communication environment information.

[0053] The communication environment information acquired by the base station device 10b includes information about backhaul, information about buffers, and capability information.

[0054] Next, the base station device 10b receives roaming information from the base station device 10a (step S112). This roaming information includes information regarding the security of the connection with the terminal device 20 and information regarding data exchange with the terminal device 20.

[0055] Next, the base station device 10b determines whether it has received the data transmitted by the base station device 10a (step S113). If it has received the data transmitted by the base station device 10a (step S113, Yes), the base station device 10b sends an acknowledgment (ACK) to the base station device 10a (step S114). At this time, the base station device 10b may also notify the base station device 10b of its latest signal-to-signal (SN) and received cache information. Next, the base station device 10b proceeds to the process in step S115.

[0056] On the other hand, if the data transmitted by the base station device 10a is not received in step S113 (step S113, No), the base station device 10b proceeds to the process in step S115.

[0057] In step S115, base station device 10b transmits a roaming response to base station device 10a (step S115). Base station device 10b may transmit a roaming response upon completion of receiving all notified data, based on the data transmission volume and data type information previously notified by base station device 10a. Alternatively, base station device 10b may transmit a roaming response after the expiration of the data transmission period, based on the data transmission period information previously notified by base station device 10a.

[0058] Next, the base station device 10b receives a response (ACK) from the base station device 10a (step S116). If the response from the base station device 10a includes the latest SN and received cache information of the base station device 10a, the base station device 10b may query its own latest SN and received cache information and, if there is a deficiency, notify the terminal device 20 of the deficiency.

[0059] [Processing of Terminal Device] Figure 7 is a diagram showing an example of the processing procedure for a terminal device according to the first embodiment of this disclosure. The same figure is a flowchart showing an example of the processing procedure for the terminal device 20.

[0060] First, the terminal device 20 exchanges communication environment information (step S121). The terminal device 20 transmits the communication environment information to the base station device 10a. The terminal device 20 also receives the communication environment information from the base station device 10a. The exchanged communication environment information includes buffer information, traffic information, and capability information indicating whether it is compatible with the operation of the present invention. The traffic information includes the amount of buffered data and information on the simultaneous transmission and reception capability on multiple links (the number of links that can simultaneously transmit and receive and whether simultaneous transmission and reception is possible on each link pair (NSTR capability)).

[0061] Next, the terminal device 20 sends a roaming request to the base station device 10a (step S122). This roaming request includes data transmission request information. This data transmission request information requests data transmission from the terminal device 20 during the roaming period. The data transmission request information includes information about the amount of data, for example, information about the status of the buffer of the terminal device 20 and information about the traffic pattern of the terminal device 20. The traffic pattern information includes, for example, information about traffic that may be generated and transmitted up to the time the roaming request is received (e.g., TID).

[0062] Next, the terminal device 20 receives an acknowledgment (ACK) (step S124). This acknowledgment may include roaming period data transmission information.

[0063] Next, the terminal device 20 transmits data to the base station device 10a (step S125). At this time, the terminal device 20 can control the transmission of data based on roaming period data transmission information. For example, if a data transmission permission period is notified, the terminal device 20 transmits data only during the specified period. Also, if a data transmission permission TID is notified, the terminal device 20 transmits only the specified TID.

[0064] Next, the terminal device 20 receives a roaming response from the base station device 10a (step S126).

[0065] [Frame Structure] Figure 8 shows an example of a roaming request frame according to the first embodiment of the present disclosure. The figure shows an example of the structure of a frame 400 applicable to a roaming request frame. Frame 400 includes an Element ID, which is the identifier of the element; a Length, which represents the length of the element; and an Element ID Extension, which is the extension identifier of the element. Frame 400 also includes a Target AP MAC address, which is the MAC address of the AP to which the terminal device 20 is switched. Frame 400 may also contain a UL traffic indication, which is information about uplink communications that may occur between the time a roaming request is sent and the time a roaming response is received. This UL traffic indication may contain, for example, information about the data size and priority (e.g., TID). Furthermore, if it is determined that data transmission is not possible, such as when sufficient uplink communication cannot be performed between base station devices during roaming, all fields may be set to "0" to notify the prohibition of uplink communication.

[0066] Figure 9 shows another example of a roaming request frame according to the first embodiment of the present disclosure. The figure shows an example configuration of frame 410 applicable to a roaming request frame. Frame 410 has a roaming request placed in the PHY header of a data frame. The U-SIG of frame 410 stores the Target AP MAC address and UL traffic indication described in Figure 8.

[0067] Figure 10 shows another example of a roaming request frame according to the first embodiment of the present disclosure. The figure shows an example configuration of a frame 420 applicable to a roaming request frame. Frame 420 has a roaming request placed in the Frame Body of the Data of a data frame.

[0068] Figures 11 and 12 show other examples of roaming request frames according to the first embodiment of the present disclosure. Figure 11 shows an example configuration of a frame 430 applicable to a roaming request frame. Frame 430 places the roaming request in the HT Control of the MAC header. The format of the HT Control field is shown in the lower left of Figure 11. In this case, by setting B0 and B1 of the HT Control field of the MAC header to "1", B2 and subsequent fields are treated as an A-Control field and new information is stored therein. An A-Control field consists of one or more Control subfields. A Control ID can also be specified in B0-B3 of each Control subfield. The type and length of the Control information are defined according to the Control ID value shown in Figure 12. In this invention, new Control information can be written to the A-Control field by defining new Control information from Control ID 10 onwards, which is designated as Reserved. In frame 430, the Target AP MAC address and UL traffic indication are stored in Control Information.

[0069] [Communication Processing] Figure 13 is a diagram showing an example of communication processing according to the first embodiment of this disclosure. The diagram is a sequence diagram showing communication processing between terminal device 20, base station device 10a, base station device 10b, and distribution system 40. In the diagram, the distribution system is denoted as DS. In the diagram, time progresses sequentially from top to bottom.

[0070] The base station device 10a measures the backhaul delay between base station devices 10a and 10b by exchanging frames for measurement in advance.

[0071] The terminal device 20 connects to the base station device 10a and transmits data (step S201). Subsequently, the terminal device 20 decides to switch the connection destination from base station device 10a to base station device 10b and sends a roaming request to base station device 10a (step S202). At this time, the terminal device 20 includes in the roaming request the amount of data that may be generated after the roaming request.

[0072] The base station device 10a sends a response to the terminal device 20 (step S203). At this time, the base station device 10a includes in the response the period during which data can be transmitted, the TID that can be transmitted, and the data size. If it is determined that data cannot be transmitted, such as when sufficient data transfer cannot be performed between the base station device 10a and the base station device 10b during roaming, the base station device 10a may notify the terminal device that data transmission is prohibited.

[0073] Next, base station device 10a transmits a roaming request and roaming information to base station device 10b (step S204). At this time, base station device 10a may include the received SN that has been transmitted to the distribution system 40 as information related to uplink communication in the roaming information. Base station device 10a also includes roaming period data transmission information in the roaming information. This roaming period data transmission information includes the transmittable period, transmittable TID, and data size that were notified to the terminal device 20 in step S203. In Figure 13, the roaming request and roaming information are transmitted in the same frame, but the roaming request and roaming information may be transmitted in separate frames.

[0074] The base station device 10b transmits a response to the base station device 10a (step S205). Next, the DS mapping change is initiated (step S206).

[0075] The terminal device 20 transmits the data for the permitted period and permitted TID to the base station device 10a (step S207). If data transmission is prohibited in step S203, the terminal device 20 does not transmit the data.

[0076] Upon receiving the data, base station device 10a transmits the data to base station device 10b (step S208). Base station device 10b transmits the data to the distribution system 40 (step S209). In this way, base station device 10b processes the data received from terminal device 20. Base station device 10b also transmits a response to base station device 10a (step S210).

[0077] After the reception of roaming information is complete and the DS mapping has been changed, upon the expiration of the period notified in step S203, the base station device 10b transmits a roaming response to the base station device 10a (step S211). At this time, the base station device 10b transmits the roaming response with the latest SN of the data transmitted from the base station device 10a. The base station device 10b may also transmit the roaming response after a backhaul delay and a certain margin period, which have been measured in advance, have elapsed from the period notified in step S203. In addition, after the DS mapping has been changed, the base station device 10b may transmit the data it has been holding to the distribution system 40.

[0078] Base station device 10a transmits a response to base station device 10b (step S212). At this time, if the latest SN received from base station device 10b is different from its own latest SN, base station device 10a may include the latest SN in the response and transmit it. Also, upon receiving the roaming response, base station device 10a transmits the roaming response to terminal device 20 (step S213). Terminal device 20 transmits a response to base station device 10a (step S214).

[0079] Subsequently, the terminal device 20 transmits data to the base station device 10b (not shown). If the base station device 10b has received the latest SN information from the base station device 10a in step S212, the base station device 10b may notify the terminal device 20 that there is unreceived data and instruct the terminal device 20 to retransmit the data to the base station device 10b.

[0080] In summary, the base station device 10a receives data and traffic information from the terminal device 20 after the roaming request has been sent. Furthermore, the base station device 10a determines roaming period data transmission information from at least one of the traffic information, the base station device 10b information, and the backhaul information, and transmits it to the terminal device 20. This roaming period data transmission information includes information on the data transmission period, TID, priority, and size. The base station device 10a receives data from the terminal device 20 during the determined period. If the base station device 10a determines that it cannot transfer data from the terminal device 20, it notifies the terminal device 20 that it will prohibit data transmission. The base station device 10a determines the timing to start changing the DS mapping based on at least one of the traffic information of the terminal device 20, the base station device 10b information, and the backhaul information. The base station device 10a transmits the data received from the terminal device 20 to the distribution system 40 before changing the DS mapping.

[0081] The base station device 10a transmits roaming period data transmission information to the base station device 10b. The base station device 10b determines the timing for transmitting the roaming response based on at least one of the received roaming period data transmission information and backhaul information.

[0082] The terminal device 20 transmits information about traffic after the roaming request has been sent to the base station device 10a. The terminal device 20 transmits data to the base station device 10a based on the roaming period data transmission information received from the base station device 10a.

[0083] Thus, the terminal device 20 and base station device 10a of the first embodiment of this disclosure can transmit and receive data during the roaming period. This enables high-speed data transmission.

[0084] (3. Second Embodiment) The terminal device 20 and base station device 10a of the first embodiment described above enabled the transmission and reception of data during the roaming period by exchanging roaming period data transmission information. In contrast, the terminal device 20 and base station device 10a of the second embodiment of this disclosure differ from the first embodiment described above in that they exchange roaming period data transmission information in advance.

[0085] [Communication Processing] Figure 14 is a diagram showing an example of communication processing according to the second embodiment of this disclosure. Similar to Figure 13, this figure is a sequence diagram showing communication processing between the terminal device 20, the base station device 10a, the base station device 10b, and the distribution system 40. Parts common to Figure 13 will not be explained.

[0086] The base station device 10a measures the backhaul delay between base station device 10a and base station device 10b by exchanging frames for measurement in advance. Alternatively, this operation may be started after receiving roaming preparation information from the terminal device 20 in step S221, and the roaming preparation information may be transmitted to the terminal device 20 after the measurement of the backhaul delay is completed.

[0087] The terminal device 20 transmits roaming preparation information to the base station device 10a (step S221). This roaming preparation information includes data transmission request information for the base station device 10b and information regarding traffic. The information for the base station device 10b may also include information about multiple candidate base station devices for migration. In addition, several possible traffic patterns may be described as traffic information, and each may be assigned an identifier (e.g., traffic pattern 1) before transmission.

[0088] Upon receiving roaming preparation information, base station device 10a may pre-transmit information that does not change or changes only slightly during communication to base station device 10b. This information may include, for example, information such as SCS (Stream Classification Service) and TWT, and security information such as PTK. At this time, this information may also be transmitted to multiple base station devices that could potentially become target base station devices.

[0089] The base station device 10a transmits a roaming readiness information response to the terminal device 20 (step S222). At this time, the base station device 10a includes the period during which data can be transmitted and the TIDs that can be transmitted in the roaming readiness information response. If the base station device 10a has received information on multiple traffic patterns from the terminal device 20, it may also include the period during which data can be transmitted and the TIDs that can be transmitted for each traffic pattern.

[0090] The terminal device 20 transmits a roaming request to the base station device 10a (step S202). If multiple traffic patterns were notified in the roaming preparation information, the terminal device 20 may only include the identifier of the current traffic pattern.

[0091] Next, base station device 10a transmits a roaming request and roaming information to base station device 10b (step S204). Next, the DS mapping change is initiated (step S206). Terminal device 20 transmits data to base station device 10a (step S207). Base station device 10a transmits data to base station device 10b (step S208). Base station device 10b transmits data to distribution system 40 (step S209). Base station device 10b also transmits a response to base station device 10a (step S210). Base station device 10b transmits a roaming response to base station device 10a (step S211). Upon receiving the roaming response, base station device 10a transmits a roaming response to terminal device 20 (step S213).

[0092] Other than those described above, the communication processing is the same as in the first embodiment of this disclosure, and therefore will not be described.

[0093] Thus, the terminal device 20 and base station device 10a of the second embodiment of this disclosure exchange roaming preparation information and roaming preparation information responses in advance and share roaming period data transmission information. This simplifies the roaming procedure.

[0094] (4. Third Embodiment) The terminal device 20 and base station device 10a of the first embodiment described above transmitted and received data after the start of the DS mapping change. In contrast, the terminal device 20 and base station device 10a of the third embodiment of this disclosure differ from the first embodiment described above in that they transmit and receive data at a time before the DS mapping change.

[0095] [Communication Processing] Figure 15 is a diagram showing an example of communication processing according to the third embodiment of this disclosure. Similar to Figure 13, this figure is a sequence diagram showing communication processing between the terminal device 20, the base station device 10a, the base station device 10b, and the distribution system 40. Note that the parts common to Figure 13 will not be explained.

[0096] The terminal device 20 sends a roaming request to the base station device 10a (step S202). The base station device 10a sends a response to the terminal device 20 (step S203). At this time, the base station device 10a may decide to send some of the data to the upper layer before changing the DS mapping, based on at least one of the information regarding the amount of data from the terminal device 20, the information regarding the base station device 10b, and the information regarding backhaul. Next, the base station device 10a sends a roaming request and roaming information to the base station device 10b (step S204). The base station device 10b sends a response to the base station device 10a (step S205).

[0097] The terminal device 20 transmits data to the base station device 10a (step S231). Next, the base station device 10a transmits the data to the distribution system 40 (step S232). In this way, the base station device 10a processes the data received from the terminal device 20. Next, the DS mapping change is initiated (step S206).

[0098] Next, base station device 10b transmits a roaming response to base station device 10a (step S211). Base station device 10a transmits a response to base station device 10b (step S212). Upon receiving the roaming response, base station device 10a transmits a roaming response to terminal device 20 (step S213). Terminal device 20 transmits a response to base station device 10a (step S214).

[0099] Other than those described above, the communication processing is the same as in the first embodiment of this disclosure, and therefore will not be described.

[0100] Thus, the terminal device 20 and base station device 10a of the third embodiment of this disclosure transmit and receive data before changing the DS mapping. This makes it possible to further speed up data transmission.

[0101] (5. Fourth Embodiment) The base station device 10a of the third embodiment described above processed the data received before the DS mapping was changed. In contrast, the base station device 10a of the present disclosure differs from the third embodiment described above in that it processes the data after the DS mapping has been changed.

[0102] [Communication Processing] Figure 16 is a diagram showing an example of communication processing according to the fourth embodiment of this disclosure. Similar to Figure 15, this figure is a sequence diagram showing communication processing between the terminal device 20, the base station device 10a, the base station device 10b, and the distribution system 40. Note that the parts common to Figure 15 will not be explained.

[0103] The terminal device 20 transmits a roaming request to the base station device 10a (step S202). The base station device 10a transmits a response to the terminal device 20 (step S203). Next, the base station device 10a transmits a roaming request and roaming information to the base station device 10b (step S204). The base station device 10b transmits a response to the base station device 10a (step S205).

[0104] The terminal device 20 transmits data to the base station device 10a (step S231). Next, the DS mapping change is initiated (step S206). Next, the base station device 10a transmits data to the distribution system 40 (step S233). The subsequent processing is the same as in Figure 15, so the explanation is omitted.

[0105] Other than those described above, the communication processing is the same as in the third embodiment of this disclosure, and therefore will not be described.

[0106] Thus, the base station device 10a of the fourth embodiment of this disclosure processes the data received before the DS mapping change after the DS mapping change.

[0107] (6. Modifications) Modifications of the above-described embodiments will now be explained.

[0108] When the base station device 10a notifies the terminal device 20 of the amount of forward uplink communication available, the terminal device 20 may not be able to select an appropriate size for the notified amount. In response to this, the terminal device 20 may decide to perform roaming and, after sending a roaming request, perform fragmentation of the data in its buffer so that it is below a certain size.

[0109] (7. Example of Computer Configuration) The series of processes described above can be executed by hardware or by software. When the series of processes are executed by software, the programs that make up the software are installed from a program storage medium onto a computer that is built into dedicated hardware, or a general-purpose personal computer.

[0110] Figure 17 is a block diagram showing an example of the hardware configuration of a computer that executes the series of processes described above by a program.

[0111] The CPU (Central Processing Unit) 801, ROM (Read Only Memory) 802, and RAM (Random Access Memory) 803 are interconnected by a bus 804.

[0112] An input / output interface 805 is further connected to the bus 804. An input unit 806, consisting of a keyboard, mouse, etc., and an output unit 807, consisting of a display, speaker, etc., are connected to the input / output interface 805. Information related to this technology, such as roaming information, may be output or displayed from the output unit 807. Information related to this technology, such as roaming information, may be input from the input unit 806, and confirmation or response to the information output or displayed to the output unit 807 may be input. In addition, a storage unit 808, consisting of a hard disk or non-volatile memory, a communication unit 809, consisting of a network interface, etc., and a drive 810 that drives removable media 811 are connected to the input / output interface 805.

[0113] In a computer configured as described above, the CPU 801 performs the series of processes described above by loading a program stored in the memory unit 808 into the RAM 803 via the input / output interface 805 and the bus 804 and executing it. For example, the CPU 801 may execute a processing program corresponding to the flowcharts in Figures 5 to 7 of this technology.

[0114] The program executed by the CPU 801 is recorded on removable media 811, for example, 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.

[0115] The programs executed by the computer may be programs that are processed chronologically in the order described herein, or they may be programs that are processed in parallel or at necessary times, such as when a call is made.

[0116] (8. Application Examples) This technology can be applied to a variety of products. For example, the communication device 10 in Figures 3 and 4 may be implemented as a mobile terminal such as a smartphone, tablet PC (Personal Computer), notebook PC, portable game terminal, or digital camera; a fixed terminal such as a television receiver, projector, printer, digital scanner, or network storage; or an in-vehicle terminal such as a car navigation system or drive recorder. The communication device 10 may also be implemented as an M2M (Machine To Machine Communication) terminal or an IoT (Internet of Things) terminal such as a smart meter, vending machine, remote monitoring device, or POS (Point of Sale) terminal. Furthermore, the communication device 10 may be implemented as a terminal requiring low latency and high reliability, such as an XR (Extended Reality / Cross Reality) device. In addition, the communication device 10 may be a wireless communication module (for example, an integrated circuit module consisting of a single die) mounted on these terminals.

[0117] On the other hand, for example, the communication device 10 may be implemented as a wireless LAN AP (wireless base station) with or without router functionality. Also, the base station devices 10a and 10b may be implemented as a mobile wireless LAN router. Furthermore, the communication device 10 may be implemented as a cellular communication base station and a femtocell. Moreover, the communication device 10 may be a wireless communication module (for example, an integrated circuit module consisting of a single die) mounted on these devices.

[0118] (Example of Smartphone Configuration) Figure 18 is a block diagram showing a schematic example of the configuration of a smartphone 900 to which this technology is applied. Although Figure 18 is shown as an example of the configuration of a smartphone 900, it is not limited to this and may be an example of the configuration of various devices and functions described above.

[0119] The smartphone 900 includes a processor 901, memory 902, 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 of the above features, or only some of them.

[0120] 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.

[0121] The memory 902 includes RAM and ROM and stores programs and data executed by the processor 901.

[0122] The storage 903 includes a storage medium such as semiconductor memory or a hard disk.

[0123] The external connection interface 904 is an interface for connecting external devices such as memory cards or USB (Universal Serial Bus) devices to the smartphone 900.

[0124] The camera 906 has an image sensor, such as a CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor), and generates an image.

[0125] The sensor 907 includes, for example, a group of sensors such as a positioning sensor, a gyroscope, a geomagnetic sensor, and an accelerometer.

[0126] Microphone 908 converts the audio input to smartphone 900 into an audio signal.

[0127] The input device 909 includes, for example, a touch sensor that detects touches 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.

[0128] 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 the output image of the smartphone 900.

[0129] Speaker 911 converts the audio signal output from smartphone 900 into audio.

[0130] The wireless communication interface 913 supports one or more wireless LAN standards, such as IEEE 802.11a, 11b, 11g, 11ac, 11ad, 11ax, 11ay, 11be, 11bn, and their successors, and performs wireless communication.

[0131] In infrastructure mode, the wireless communication interface 913 communicates with other devices via a wireless LAN access point (AP). In ad-hoc mode or direct communication modes such as Wi-Fi Direct, the wireless communication interface 913 communicates directly with other devices.

[0132] In Wi-Fi Direct, unlike ad-hoc mode, one of the two devices acts as the access point (AP), but communication takes place directly between those devices.

[0133] The wireless communication interface 913 typically includes a baseband processor, an RF (Radio Frequency) circuit, and a power amplifier. The wireless communication interface 913 may also be a single-chip module integrating a memory for storing a communication control program, a processor for executing the program, and associated circuits.

[0134] The wireless communication interface 913 may support other types of wireless communication methods in addition to the wireless LAN method, such as short-range wireless communication methods like Bluetooth®, proximity wireless communication methods like NFC, or 3GPP® cellular communication methods such as 2G, 3G, 4G, 5G, and 6G. The wireless communication interface 913 may be a single-chip module that supports multiple wireless communication methods, or it may be a combination of modules that support some of the wireless communication methods.

[0135] The antenna switch 914 switches the destination of the antenna 915 among multiple circuits included in the wireless communication interface 913 (for example, circuits for different wireless communication methods, or transmitting and receiving circuits).

[0136] The antenna 915 has one or more antenna elements (for example, multiple antenna elements that make up a MIMO (Multiple Input Multiple Output) antenna, or multiple antenna elements that make up an array antenna) and is used for transmitting and receiving radio signals via the wireless communication interface 913.

[0137] Note that the smartphone 900 is not limited to the example in Figure 18, and may have multiple antennas (for example, an antenna for wireless LAN, an antenna for proximity wireless communication, and an antenna for cellular communication). In that case, the antenna switch 914 may be omitted from the configuration of the smartphone 900.

[0138] 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.

[0139] The battery 918 supplies power to each block of the smartphone 900 shown in Figure 18 via power supply lines partially shown by dashed lines 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 reading of information regarding the remaining power, cumulative power supply time, or cumulative power supply amount, and the processor 901, wireless communication interface 913, or auxiliary controller 919 may control any of the functions of the above embodiments based on the information read from the battery 918.

[0140] In the smartphone 900 shown in Figure 18, for example, the communication control unit 117 and control unit 120 in Figures 3 and 4 may be implemented in the wireless communication interface 913. For example, the processing program corresponding to the flowcharts in Figures 5 to 7 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.

[0141] The smartphone 900 may also operate as a wireless AP (software AP) by having the processor 901 execute AP functions at the application level. Alternatively, the wireless communication interface 913 may have wireless AP functionality. Furthermore, the processor 901 or the wireless communication interface 913 may have a tethering function using both wireless LAN and cellular communication methods, and may transmit payload data received via cellular communication using the wireless LAN method, or transmit payload data received via wireless LAN using the cellular communication method. The smartphone 900 may also enable the tethering function through user input.

[0142] Furthermore, the smartphone 900 may be equipped with a biometric authentication unit (fingerprint authentication, palm print authentication, voice authentication, vascular authentication, facial authentication, iris authentication, and retinal authentication). In this case, the wireless communication interface 913 on which the communication control unit 117 and control unit 120 shown in Figures 3 and 4 are implemented is configured to receive power from the same battery 918 as at least one of the display device 910, speaker 911, and biometric authentication unit.

[0143] Furthermore, in the smartphone 900, information is displayed from 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. In this case, information related to this technology, such as roaming information, may be output from at least one of the display device 910 and the speaker 911. The input device 909 may also be configured to input confirmation or a response to the information output from at least one of the display device 910 and the speaker 911.

[0144] (Example of In-Vehicle Device Configuration) Figure 19 is a block diagram showing an example of the schematic configuration of an in-vehicle device 920 to which this technology is applied. Although Figure 19 is described as an example of the configuration of an in-vehicle device 920, it is not limited to this, and may be an example of the configuration of various devices and functions described above.

[0145] The in-vehicle device 920 is configured to include a processor 921, memory 922, GNSS (Global Navigation Satellite System) module 924, sensor 925, data interface 926, content player 927, and storage medium interface 928. The in-vehicle device 920 is also configured to include an input device 929, display device 930, speaker 931, wireless communication interface 933, antenna switch 934, antenna 935, and battery 938. The in-vehicle device 920 may include all of the above, or it may include some of them.

[0146] The processor 921 may be, for example, a CPU or SoC, and controls the navigation and other functions of the in-vehicle device 920. The processor 921 can also control the vehicle's drive system, such as the brakes, accelerator, or steering, based on information obtained through communication based on this technology.

[0147] The memory 922 includes RAM and ROM and stores programs and data executed by the processor 921.

[0148] The GNSS module 924 uses GNSS signals received from GNSS satellites to measure the position (e.g., latitude, longitude, and altitude) of the on-board device 920.

[0149] The sensor 925 includes, for example, a group of sensors such as a gyro sensor, a geomagnetic sensor, a millimeter-wave radar, a camera (image sensor such as a CCD or CMOS), and a barometric pressure sensor.

[0150] The data interface 926 is connected to the in-vehicle network 941, for example, via terminals (not shown), and acquires data generated on the vehicle side, such as vehicle-side data.

[0151] 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.

[0152] The input device 929 includes, for example, a touch sensor, button, or switch that detects touches on the screen of the display device 930, and accepts operations or information input from the user. For example, the input device 929 may also receive confirmation or a response to information output from at least one of the display device 930 and the speaker 931.

[0153] The display device 930 has a screen such as an LCD, OLED display, or QD display, and displays navigation functions or images of content to be played, as well as information about this technology, such as information about frequency resources.

[0154] The speaker 931 outputs navigation functions, audio of the content being played, or information about this technology, such as information about frequency resources.

[0155] Note that in the in-vehicle device 920, the navigation function and the functions provided by the content player 927 are optional. The navigation function and the content player 927 may be omitted from the configuration of the in-vehicle device 920.

[0156] The wireless communication interface 933 supports one or more wireless LAN standards, such as IEEE 802.11a, 11b, 11g, 11n, 11ac, 11ad, 11ax, 11ay, 11be, 11bn, and their successors, and performs wireless communication.

[0157] In infrastructure mode, the wireless communication interface 933 communicates with other devices via a wireless LAN access point (AP). In ad-hoc mode or direct communication modes such as Wi-Fi Direct, the wireless communication interface 933 communicates directly with other devices.

[0158] In Wi-Fi Direct, unlike ad-hoc mode, one of the two devices acts as the access point (AP), but communication takes place directly between those devices.

[0159] The wireless communication interface 933 typically includes a baseband processor, RF circuitry, and power amplifier. The wireless communication interface 933 may also be a single-chip module integrating a memory for storing a communication control program, a processor for executing the program, or related circuitry.

[0160] The wireless communication interface 933 may support other types of wireless communication methods in addition to the wireless LAN method, such as short-range wireless communication methods like Bluetooth®, proximity wireless communication methods like NFC, or 3GPP® cellular communication methods such as 2G, 3G, 4G, 5G, and 6G. The wireless communication interface 933 may be a single-chip module that supports multiple wireless communication methods, or it may be a combination of modules that support some of the wireless communication methods.

[0161] The antenna switch 934 switches the destination of the antenna 935 among multiple circuits included in the wireless communication interface 933 (for example, circuits for different wireless communication methods, or transmitting and receiving circuits).

[0162] The antenna 935 has one or more antenna elements (for example, multiple antenna elements that make up a MIMO (Multiple Input Multiple Output) antenna, or multiple antenna elements that make up an array antenna) and is used for transmitting and receiving radio signals via the wireless communication interface 933.

[0163] Note that the in-vehicle device 920 is not limited to the example shown in Figure 19, and may include multiple antennas 935 (for example, an antenna for wireless LAN, an antenna for proximity wireless communication, and an antenna for cellular communication). In that case, the antenna switch 934 may be omitted from the configuration of the in-vehicle device 920.

[0164] The battery 938 supplies power to each block of the on-board device 920 shown in Figure 19 via the power supply lines partially shown by dashed lines in the figure. The battery 938 may also store power supplied from the vehicle. Alternatively, the on-board device 920 may not have a battery and may utilize power supplied from the vehicle via a voltage regulator or capacitor.

[0165] In the in-vehicle device 920 shown in Figure 19, for example, the communication control unit 117 and control unit 120 in Figures 3 and 4 may be implemented in the wireless communication interface 933. For example, the processing program corresponding to the flowcharts in Figures 5 to 7 may be executed in the wireless communication interface 933. Furthermore, at least some of these functions may be implemented in the processor 921.

[0166] Furthermore, the wireless communication interface 933 may operate as the base station devices 10a and 10b described above, providing wireless connectivity to terminals held by users 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 utilize CarPlay® or Android Auto®. The wireless communication interface 933 may also connect the in-vehicle device 920 to other peripheral devices using a short-range wireless communication method, infrastructure mode, or a Wi-Fi Direct wireless LAN method.

[0167] The in-vehicle device 920 may also operate as a wireless AP (software AP) by having the processor 921 execute AP functions at the application level. Alternatively, the wireless communication interface 933 may have wireless AP functionality. Furthermore, the processor 921 or the wireless communication interface 933 may have a tethering function using both wireless LAN and cellular communication methods, and may transmit payload data received via cellular communication using the wireless LAN method, or transmit payload data received via wireless LAN using the cellular communication method. The tethering function of the in-vehicle device 920 may be enabled by user input.

[0168] Furthermore, this technology may be implemented 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 speed information, vehicle-side battery information, or fault information, and output the generated data to the in-vehicle network 941. The processor 921 or 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.

[0169] (Example of Wireless AP Configuration) Figure 20 is a block diagram showing an example of a schematic configuration of a wireless AP 950 to which this technology is applied. Although Figure 20 is shown as an example of the configuration of a wireless AP 950, it is not limited to this and may also be an example of the configuration of various devices and functions described above.

[0170] The wireless AP950 includes a controller 951, memory 952, input device 954, display device 955, network interface 957, wireless communication interface 963, antenna switch 964, and antenna 965. The wireless AP950 may include all of the above, or some of them.

[0171] The controller 951 may be, for example, a CPU or a DSP (Digital Signal Processor) and operates various functions of the wireless AP 950 at the IP (Internet Protocol) layer and higher layers (e.g., access restriction, routing, encryption, firewall, and log management).

[0172] Memory 952 includes RAM and ROM and stores programs executed by the controller 951, as well as various control information (e.g., terminal list, routing table, encryption key, security settings, and logs).

[0173] The input device 954 includes, for example, buttons and switches, and accepts user input. For example, the input device 954 may accept confirmation or response to information output from the display device 955. The input device 954 may also accept user input such as switching the wireless function on / off, and switching between router function and access point function.

[0174] The display device 955 includes an LED lamp or the like and displays the operating status of the wireless AP 950. The display device 955 may also display information related to this technology, such as information related to frequency resources.

[0175] The network interface 957 is a wired communication interface for the wireless AP 950 to connect to the wired communication network 958. The network interface 957 may have multiple connection terminals. The network interface 957 may output payload data included in the wireless signal input from the wireless communication interface 963 as a wired signal, or it may receive payload data output as a wireless signal from the wireless communication interface 963 as a wired signal, or it 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 a WAN (Wide Area Network).

[0176] 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 connectivity as an AP to nearby terminals. When the wireless AP 950 is mounted on a cellular communication base station and femtocell, the wireless communication interface 963 may support other types of wireless communication methods in addition to wireless LAN methods, such as 3GPP® cellular communication methods including 2G, 3G, 4G, 5G, and 6G. The wireless communication interface 963 may be a single-chip module supporting multiple wireless communication methods, or a combination of modules supporting some of the wireless communication methods.

[0177] The wireless communication interface 963 typically includes a baseband processor, RF circuitry, and power amplifiers, among others.

[0178] The wireless communication interface 963 may be a single-chip module integrating a memory for storing a communication control program, a processor for executing the program, or related circuits.

[0179] The antenna switch 964 switches the destination of the antenna 965 among multiple circuits included in the wireless communication interface 963 (for example, circuits for different wireless communication methods, or transmitting and receiving circuits).

[0180] The antenna 965 has one or more antenna elements (for example, multiple antenna elements that make up a MIMO (Multiple Input Multiple Output) antenna, or multiple antenna elements that make up an array antenna) and is used for transmitting and receiving radio signals via the wireless communication interface 963.

[0181] In the wireless AP 950 shown in Figure 20, for example, the communication control unit 117 and control unit 120 in Figures 3 and 4 may be implemented in the wireless communication interface 963. For example, the processing program corresponding to the flowcharts in Figures 5 to 7 may be executed in the wireless communication interface 963. Furthermore, at least some of these functions may be implemented in the controller 951.

[0182] (Other variations) The control device for controlling the communication device 10 of this embodiment may be implemented by a dedicated computer system or by a general-purpose computer system.

[0183] For example, a communication program for performing the above-described operations is stored in a computer-readable recording medium such as an optical disc, semiconductor memory, magnetic tape, or flexible disk and distributed. Then, for example, the control device is configured by installing the program on a computer and executing the above-described process. In this case, the control device may be an external device to the communication device 10 (for example, a personal computer). Alternatively, the control device may be an internal device to the communication device 10.

[0184] For example, CDs (Compact Discs), MDs (MiniDiscs), DVDs (Digital Versatile Discs), memory cards, and Blu-ray Discs (Blu-ray® Discs) can be used as recording media.

[0185] Alternatively, the above-mentioned communication program may be stored on a disk device provided by a server on a network such as the Internet, and made available for download to a computer. Furthermore, the above-mentioned functions may be realized through the cooperation of an OS (Operating System) and application software. In this case, the parts other than the OS may be stored on a medium and distributed, or the parts other than the OS may be stored on a server device and made available for download to a computer.

[0186] Furthermore, among the processes described in the above embodiments, all or part of the processes described as being performed automatically can be performed manually, or all or part of the processes described as being performed manually can be performed automatically by known methods. In addition, the processing procedures, specific names, and information including various data and parameters shown in the above document and drawings can be arbitrarily changed unless otherwise specified. For example, the various information shown in each figure is not limited to the information shown.

[0187] Furthermore, the components of each illustrated device are functionally conceptual and do not necessarily need to be physically configured as shown. In other words, the specific forms of distribution and integration of each device are not limited to those shown, and all or part of them can be functionally or physically distributed and integrated in any unit according to various loads and usage conditions. This distribution and integration configuration may also be performed dynamically.

[0188] Furthermore, the above-described embodiments can be combined as appropriate in areas where the processing content is not contradictory. Also, the order of each step shown in the flowchart of the above-described embodiments can be changed as appropriate.

[0189] Furthermore, some or all of the communication device 10 described in the above-described embodiment may be implemented as, for example, a semiconductor chip (IC (Integrated Circuit)) having a wireless communication control function. Alternatively, it may be implemented as a single semiconductor chip equipped with multiple functions, such as an SoC (System on Chip), or as a combination of multiple semiconductor chips having a single function, such as a processor. Moreover, multiple SoCs may be combined, or a single-function semiconductor chip may be combined with an SoC. Furthermore, each part may be implemented as a dedicated semiconductor chip such as an ASIC (Application Specific Integrated Circuit), or as a combination of a general-purpose processor and software or firmware, or as a semiconductor chip such as an FPGA (Field Programmable Gate Array).

[0190] Furthermore, for example, this embodiment can also be implemented as any configuration that constitutes a device or system, such as a processor as a system LSI (Large Scale Integration), a module using multiple processors, a unit using multiple modules, or a set with additional functions added to a unit (i.e., a configuration of a part of a device).

[0191] In this embodiment, a system refers to a collection of multiple components (devices, modules (parts), etc.), regardless of whether all components are located in the same enclosure. Therefore, multiple devices housed in separate enclosures and connected via a network, and a single device containing multiple modules within a single enclosure, are both considered systems.

[0192] Furthermore, for example, this embodiment can adopt a cloud computing configuration in which a single function is shared and processed collaboratively by multiple devices via a network.

[0193] Although the embodiments of this disclosure have been described above, the technical scope of this disclosure is not limited to the embodiments described above, and various modifications are possible without departing from the gist of this disclosure. Furthermore, components from different embodiments and modifications may be combined as appropriate.

[0194] The series of processes performed by each device described herein may be implemented using software, hardware, or a combination of software and hardware. The programs constituting the software are pre-stored in a storage medium (non-transitory media) provided inside or outside each device. Then, each program is loaded into RAM when the computer is running and executed by a processor such as a CPU.

[0195] Furthermore, the processes described herein using flowcharts and sequence diagrams do not necessarily have to be executed in the order shown. Some processing steps may be executed in parallel. Additional processing steps may be adopted, and some processing steps may be omitted.

[0196] Furthermore, if a single step includes multiple processes, those processes can be executed by a single device or shared among multiple devices.

[0197] The above-described embodiments are merely examples of how to realize this technology, and there is a corresponding relationship between the matters in the embodiments and the inventive features in the claims. Similarly, there is a corresponding relationship between the inventive features in the claims and the matters in the embodiments of this technology that bear the same name. However, this technology is not limited to the embodiments and can be realized by making various modifications to the embodiments without departing from the gist of the technology.

[0198] Furthermore, the effects described herein are merely illustrative and not limiting, and other effects may also occur.

[0199] Furthermore, this technology can also be configured as follows: (1) A wireless communication device having a control unit that performs the following: control to receive a roaming request transmitted from a terminal device; control to transmit roaming period data transmission information, which is information for data transmission during the roaming period of the terminal device, to transmit roaming information based on the roaming request to a base station device; control to receive data from the terminal device during the roaming period; and control to transmit the roaming period data transmission information to the base station device. (2) The wireless communication device according to (1), wherein the control unit further performs control to transfer the received data to the base station device. (3) The wireless communication device according to (1), wherein the control unit further performs control to process the received data. (4) The wireless communication device according to any one of (1) to (3), wherein the roaming period data transmission information includes at least one of the data transmission period, a data identifier, and the data size. (5) The wireless communication device according to any one of (1) to (4) above, wherein the control unit controls the transmission of roaming period data transmission information in response to data transmission request information, which is information requesting data transmission from the terminal device during the roaming period. (6) The wireless communication device according to (5) above, wherein the data transmission request information includes the amount of data. (7) The wireless communication device according to (5) above, wherein the control unit receives the roaming request including the data transmission request information and further controls the transmission of a response to the roaming request including the roaming period data transmission information to the terminal device. (8) The wireless communication device according to (5) above, wherein the data transmission request information is transmitted in roaming preparation information transmitted from the terminal device before the reception of the roaming request, and the control unit further controls the transmission of the roaming preparation information including the roaming period data transmission information to the terminal device. (9) The wireless communication device according to any one of (1) to (8) above, wherein the roaming information includes at least one of information relating to connection with the terminal device and information relating to data exchange with the terminal device.(10) The wireless communication device according to any one of (1) to (9), wherein the control unit further performs control to transmit communication environment information including capability information to the terminal device and the base station device. (11) A wireless communication device having a control unit that performs control to receive roaming information based on a roaming request from a terminal device transmitted by the base station device, control to receive roaming period data transmission information which is information for data transmission during the roaming period of the terminal device transmitted by the base station device, and control to receive data from the terminal device transmitted by the base station device. (12) The wireless communication device according to (11), wherein the control unit further performs control to process the received data. (13) The wireless communication device according to (11) or (12), wherein the roaming period data transmission information includes at least one of a data transmission period, a data identifier, and the size of the data. (14) The wireless communication device according to any one of (11) to (13), wherein the roaming information includes at least one of information relating to connection with the terminal device and information relating to data exchange with the terminal device. (15) The wireless communication device according to any one of (11) to (14), wherein the control unit further performs control to transmit communication environment information including capability information to the base station device. (16) A wireless communication device having a control unit that performs control to transmit a roaming request to the base station device, control to receive roaming period data transmission information which is information for data transmission during the roaming period from the base station device, and control to transmit data to the base station device based on the roaming period data transmission information. (17) The wireless communication device according to (16), wherein the control unit further performs control to transmit data transmission request information which is information requesting data transmission during the roaming period to the base station device. (18) The wireless communication device according to (17), wherein the data transmission request information includes the amount of data. (19) The wireless communication device according to (17) or (18), wherein the control unit transmits the roaming request including the data transmission request information to the base station device.(20) The control unit further performs control to transmit roaming readiness information to the base station device before transmitting the roaming request, and control to receive a response of the roaming readiness information from the base station device, wherein the roaming readiness information includes the data transmission request information, and the response of the roaming readiness information includes the roaming period data transmission information, according to any one of (17) to (19). (21) The wireless communication device according to any one of (16) to (20) wherein the roaming period data transmission information includes at least one of the data transmission period, a data identifier, and the data size. (22) The wireless communication device according to any one of (16) to (21) further performs control to transmit communication environment information including capability information to the base station device. (23) A wireless communication method comprising: receiving a roaming request transmitted from a terminal device; transmitting roaming period data transmission information, which is information for data transmission during the roaming period of the terminal device, to the terminal device; transmitting roaming information based on the roaming request to a base station device; receiving data from the terminal device during the roaming period; and transmitting the roaming period data transmission information to the base station device. (24) A wireless communication method comprising: receiving roaming information based on a roaming request from a terminal device transmitted by a base station device; receiving roaming period data transmission information, which is information for data transmission during the roaming period of the terminal device, transmitted by the base station device; and receiving data from the terminal device transmitted by the base station device. (25) A wireless communication method comprising: transmitting a roaming request to a base station device; receiving roaming period data transmission information, which is information for data transmission during the roaming period, from the base station device; and transmitting data to the base station device based on the roaming period data transmission information.

[0200] 10 Communication equipment Base station equipment 10a, 10b Terminal equipment 20 117 Communication control unit 120 Control unit

Claims

1. A wireless communication device having a control unit that performs the following actions: receiving a roaming request transmitted from a terminal device; transmitting roaming period data transmission information, which is information for data transmission during the roaming period of the terminal device, to the terminal device; transmitting roaming information based on the roaming request to a base station device; receiving data from the terminal device during the roaming period; and transmitting the roaming period data transmission information to the base station device.

2. The wireless communication device according to claim 1, further performing control on the control unit to transfer the received data to the base station device.

3. The wireless communication device according to claim 1, wherein the control unit further performs control for processing the received data.

4. The wireless communication device according to claim 1, wherein the roaming period data transmission information includes at least one of the data transmission period, a data identifier, and the data size.

5. The wireless communication device according to claim 1, wherein the control unit performs control to transmit roaming period data transmission information in response to data transmission request information, which is information requesting data transmission from the terminal device during the roaming period.

6. The wireless communication device according to claim 5, wherein the data transmission request information includes the amount of data.

7. The wireless communication device according to claim 5, wherein the control unit receives the roaming request including the data transmission request information and further performs control to transmit a response to the roaming request including the roaming period data transmission information to the terminal device.

8. The wireless communication device according to claim 5, wherein the data transmission request information is transmitted in roaming preparation information transmitted from the terminal device before the reception of the roaming request, and the control unit further performs control to receive the roaming preparation information and control to transmit a response of the roaming preparation information, including the roaming period data transmission information, to the terminal device.

9. The wireless communication device according to claim 1, wherein the roaming information includes at least one of information relating to connection with the terminal device and information relating to data exchange with the terminal device.

10. The wireless communication device according to claim 1, wherein the control unit further performs control to transmit communication environment information including capability information to the terminal device and the base station device.

11. A wireless communication device having a control unit that performs the following actions: receiving roaming information based on a roaming request from a terminal device transmitted by a base station device; receiving roaming period data transmission information which is information for data transmission during the roaming period of the terminal device transmitted by the base station device; and receiving data from the terminal device transmitted by the base station device.

12. The wireless communication device according to claim 11, wherein the control unit further performs control for processing the received data.

13. The wireless communication device according to claim 11, wherein the roaming period data transmission information includes at least one of the data transmission period, a data identifier, and the data size.

14. The wireless communication device according to claim 11, wherein the roaming information includes at least one of information relating to connection with the terminal device and information relating to data exchange with the terminal device.

15. The wireless communication device according to claim 11, wherein the control unit further performs control to transmit communication environment information including capability information to the base station device.

16. A wireless communication device having a control unit that performs the following actions: control to transmit a roaming request to a base station device; control to receive roaming period data transmission information, which is information for data transmission during the roaming period, from the base station device; and control to transmit data to the base station device based on the roaming period data transmission information.

17. The wireless communication device according to claim 16, wherein the control unit further performs control to transmit data transmission request information, which is information requesting data transmission during the roaming period, to the base station device.

18. The wireless communication device according to claim 17, wherein the data transmission request information includes the amount of data.

19. The wireless communication device according to claim 17, wherein the control unit transmits the roaming request, including the data transmission request information, to the base station device.

20. The wireless communication device according to claim 17, wherein the control unit further performs control to transmit roaming preparation information to the base station device before transmitting the roaming request, and control to receive a response of the roaming preparation information from the base station device, wherein the roaming preparation information includes the data transmission request information, and the response of the roaming preparation information includes the roaming period data transmission information.

21. The wireless communication device according to claim 16, wherein the roaming period data transmission information includes at least one of the data transmission period, a data identifier, and the data size.

22. The wireless communication device according to claim 16, wherein the control unit further performs control to transmit communication environment information including capability information to the base station device.

23. A wireless communication method comprising: receiving a roaming request transmitted from a terminal device; transmitting roaming period data transmission information, which is information for data transmission during the roaming period of the terminal device, to the terminal device; transmitting roaming information based on the roaming request to a base station device; receiving data from the terminal device during the roaming period; and transmitting the roaming period data transmission information to the base station device.

24. A wireless communication method comprising: receiving roaming information based on a roaming request from a terminal device transmitted by a base station device; receiving roaming period data transmission information which is information for data transmission during the roaming period of the terminal device transmitted by the base station device; and receiving data from the terminal device transmitted by the base station device.

25. A wireless communication method comprising: transmitting a roaming request to a base station device; receiving roaming period data transmission information, which is information for data transmission during the roaming period, from the base station device; and transmitting data to the base station device based on the roaming period data transmission information.

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