Communication device and communication method

Abstract

Provided is a communication device which performs multi-link operation by means of synchronous transmission.　The communication device is provided with a communication unit which communicates using a plurality of links, and a control unit which controls the communication operation performed by the communication unit. The control unit performs control to transmit a signal containing information relating to a period for implementing data transmission using the plurality of links. The information relating to the period includes at least one item of information from among the start time of the period, the duration of the period, and the links which are to implement transmission during the period. The control unit controls the description of the information relating to the start time of the period and the duration of the period such that the periods overlap in each link used for the data transmission.

Description

[Technical field]

[0001] The technology disclosed in this specification (hereinafter referred to as "the present disclosure") relates to a communication device and a communication method that perform wireless communication by bundling a plurality of links. [Background technology]

[0002] In recent years, data traffic in wireless communication has been increasing due to the transmission of virtual reality (VR) and 8K video. To accommodate this traffic, wireless local area networks (LANs) are required to improve their throughput. Currently, standardization of multi-link operation (MLO), which bundles multiple links for communication, is being promoted as a useful technology for improving throughput.

[0003] MLO can be broadly divided into two types: asynchronous transmission, in which each link communicates independently, and synchronous transmission, in which the transmission timing is perfectly aligned between links. In MLO, the channels between links are close to each other, causing leakage, making it difficult to transmit on one link while receiving on another. In this case, if a synchronous transmission method is used, in which the transmission timing is aligned across multiple links, simultaneous transmission and reception between links does not occur, and the benefits of MLO can be achieved.

[0004] When implementing MLO using synchronous transmission, it is required that all links used are capable of transmitting at the same time, in other words, that each link be in an idle state at the same time. However, terminals that do not support MLO, such as legacy terminals, use only one link and transmit independently of other links. For this reason, the time during which multiple links are all idle and synchronous transmission can be performed is limited, and the effect of improving throughput by MLO cannot be expected.

[0005] In addition, IEEE802.11ax standardizes the operation of setting a period called Quiet Time Period (QTP). This is an operation to set a period during which a terminal suppresses transmissions of other terminals in a BSS (Basic Service Set) in order to prioritize communication of a certain method. In QTP operation, first, a terminal that wants to communicate in a certain method transmits a QTP request to an access point, and the access point returns a QTP response to the terminal. Next, when the start timing of the period during which transmissions of other terminals indicated by the QTP request and QTP response are suppressed, the access point transmits QTP Setup to surrounding terminals. When a terminal other than the sender of the QTP request receives QTP Setup, it suppresses transmissions for a period equivalent to the Duration described in the frame. This makes it possible to prevent communication other than communication between terminals from occurring. However, in order to suppress transmissions of terminals on each link in order to implement MLO, it is necessary to transmit QTP Setup simultaneously across multiple links at the start timing. In the first place, there is a technical issue that simultaneous transmission cannot be performed on multiple links, so MLO by synchronous transmission cannot be realized using QTP operation. In addition, a wireless LAN system has been proposed in which the transmission of a frame including a silence element and a silence channel element indicates that the second subchannel is to be silenced during the silence period, and further indicates the conditions and period under which the first subchannel may be used (see Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Special Publication No. 2014-522196 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present disclosure is to provide a communication device and a communication method that perform MLO using synchronous transmission. [Means for solving the problem]

[0008] The present disclosure has been made in consideration of the above problems, and a first aspect thereof is: A communication unit that performs communication via a plurality of links; A control unit that controls a communication operation by the communication unit; Equipped with The control unit controls to transmit a signal including information regarding a period during which data transmission is to be performed through the plurality of links. It is a communication device.

[0009] The information regarding the period includes at least one of information on a start time of the period, a duration of the period, and a link through which transmission is performed during the period. The control unit controls writing of information regarding the start time of the period and the duration of the period so that the periods overlap on each link used for the data transmission.

[0010] The second aspect of the present disclosure is A communication method for a communication device that communicates via a plurality of links, comprising: setting a period during which data transmission is to be performed on the plurality of links; transmitting a signal containing information regarding said period; It is a communication method having the above structure.

[0011] Moreover, a third aspect of the present disclosure is a communication unit that performs communication through at least one of the multiple links; A control unit that controls a communication operation by the communication unit; Equipped with the control unit receives a signal including information regarding a period during which data transmission is to be performed on the plurality of links via at least one of the plurality of links, and controls to suppress transmission on the link that received the signal including the information regarding the period. It is a communication device.

[0012] The information regarding the period includes at least one of information regarding a start time of the period, a duration of the period, and a link over which transmission is performed during the period. The control unit controls to suppress transmission on the link over which the signal is received, based on the start time of the period and the duration of the period described in the signal.

[0013] Moreover, a fourth aspect of the present disclosure is A communication method for a communication device that communicates via a plurality of links, comprising: receiving, on at least one of the plurality of links, a signal including information regarding a period during which data transmission is to be performed on the plurality of links; suppressing transmissions on links receiving a signal containing information about said time period; It is a communication method having the above structure. Effect of the Invention

[0014] According to the present disclosure, it is possible to provide a communication device and a communication method that perform MLO using synchronous transmission.

[0015] Note that the effects described in this specification are merely examples, and the effects brought about by the present disclosure are not limited thereto. Furthermore, the present disclosure may have additional effects in addition to the effects described above.

[0016] Further objects, features and advantages of the present disclosure will become apparent from the following detailed description based on the embodiments and the accompanying drawings. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a communication system 100. [Diagram 2] FIG. 2 is a diagram showing an example of channel selection for a first link (link1) and a second link (link2). [Diagram 3] FIG. 3 is a diagram showing an example of channel selection for a first link (link1) and a second link (link2). [Figure 4] FIG. 4 is a diagram showing an example of the configuration of the communication device 200. As shown in FIG. [Diagram 5] FIG. 5 is a diagram showing an example of a communication sequence (first operation example) for performing MLO. [Figure 6] FIG. 6 is a diagram showing an example of the format of the MLP Setup frame. [Figure 7] FIG. 7 is a diagram showing an example of the format of the MLP Request frame. [Figure 8] FIG. 8 is a diagram showing an example of the format of the MLP End frame. [Figure 9] FIG. 9 is a diagram showing an example of the format of the MLP Advertisement frame. [Figure 10] FIG. 10 is a diagram showing an example of the format of the MLP Advertisement Response frame. [Figure 11] FIG. 11 is a diagram showing an example of a communication sequence for performing MLO (a modified example of the first operation example). [Figure 12] FIG. 12 is a flowchart showing a process procedure executed when a communication device (MLD) operating as an AP performs MLO. [Figure 13] FIG. 13 is a flowchart showing a processing procedure executed by a communication device (MLD) operating as a STA when MLO is performed. [Figure 14] FIG. 14 is a diagram showing an example of a communication sequence (second operation example) for performing MLO. [Figure 15] FIG. 15 is a diagram showing an example of a communication sequence (second operation example) for performing MLO. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The present disclosure will now be described with reference to the drawings in the following order. A. Overview B. System Configuration C. Equipment configuration D. Example of operation 1 E. Frame Format F. Modification of Operation Example 1 G. Operation of communication devices H. Example of operation 2 I. Effects

[0019] A. Overview In the present disclosure, a terminal that wishes to perform MLO (hereinafter also simply referred to as "multi-link transmission") of a synchronous transmission method, or a terminal that has received a request from that terminal, transmits a signal (MLP Setup frame) for suppressing transmission of each terminal during the multi-link period (MLP) in which MLO is performed, to surrounding terminals on multiple links before the start timing of the MLP. The MLP Setup frames transmitted on each link are transmitted at different timings, and notify the time (offset) from each transmission timing to the start timing of the MLP and the length of the MLP. A terminal that receives the MLP Setup frame suppresses transmission for the specified period. For legacy terminals that do not support the present disclosure, the duration of the MLP Setup frame is also set to match the length of the MLP.

[0020] Therefore, a terminal attempting to perform multi-link transmission transmits an MLP Setup frame on each link to notify the time until the start of the MLP and the length of the MLP, so that when the MLP arrives, it suppresses transmissions by surrounding terminals, making it easier to seize the opportunity for multi-link transmission.

[0021] B. System Configuration 1 is a schematic diagram showing a configuration example of a communication system 100 to which the present disclosure is applied. The illustrated communication system 100 is configured with an access point (AP) 110 and a terminal (STA) 120. The terminal 120 is not an access point, i.e., a non-AP. In the communication system 100, a first link and a second link are available, and the access point 110 and the terminal 120 are connected via the first link and the second link.

[0022] Both the access point 110 and the terminal 120 are communication devices (Multi-link Devices:MLDs) that perform MLO using a first link (link1) and a second link (link2), that is, AP MLD and non-AP MLD, respectively. Note that hereinafter, when simply referring to "multi-link operation" or MLO, it refers to MLO by synchronous transmission unless otherwise specified.

[0023] In the example shown in FIG. 1, the access point 110 includes two access points, AP1-1 operating on the first link and AP1-2 operating on the second link. The terminal 120 includes two terminals, non-AP STA1-1 operating on the first link and non-AP STA1-2 operating on the second link. However, the number of access points and terminals included in the access point 110 and the terminal 120, respectively, is not limited to two, and may be three or more. That is, the number of links connecting the access point 110 and the terminal 120 is not limited to two, and may be connected through three or more links. In addition, in FIG. 1, only one access point and one terminal are drawn in the communication system 100 for the sake of simplicity of the drawing, but multiple access points and terminals may be connected. In addition, one communication device may include one or more access points (AP MLD) and one or more terminals (non-AP MLD).

[0024] The MLD management entity is an entity that manages the operations in the access point 110 and the terminal 120, which are MLDs. Also, the MAC-SAP to LLC is a point (Service Access Point) that provides MAC layer services to the LLC (Logical Link Control) layer, which is an upper layer of the MAC (Media Access Control) layer.

[0025] A "link" in this specification refers to a wireless transmission path that can transmit data between two communication devices. Each link is selected from a plurality of mutually independent wireless transmission paths (channels) divided, for example, in the frequency domain. Figures 2 and 3 show two examples of channel selection for a first link (link1) and a second link (link2) used in the communication system 100. In each figure, band A and band B are either of bands such as 2.4 GHz band, 5 GHz band, 6 GHz band, and 920 GHz band. Band A and band B may be, for example, unlicensed bands that do not require a radio station license, and use is permitted by database access such as SAS (Spectrum Access System).

[0026] Band A and band B each include a plurality of channels. In the example shown in Fig. 2 and Fig. 3, band A consists of six channels, and band B consists of five channels. MLDs such as access point 110 and terminal 120 operating in communication system 100 select channels to be used for a first link (link1) and a second link (link2) from band A and band B. In the example shown in Fig. 2, channels to be used for the first link (link1) and the second link (link2) are selected from band A. Also, in the example shown in Fig. 3, a channel to be used for the first link (link1) is selected from band A, and a channel to be used for the second link (link2) is selected from band B.

[0027] C. Equipment configuration 4 shows a configuration example of a communication device 200 capable of operating as the access point 110 and the terminal 120. The communication device 200 is a device that performs multi-link operation using a first link (link1) and a second link (link2), that is, an MLD.

[0028] The illustrated communication device 200 is composed of a control unit 210, a power supply unit 220, multiple (two in the illustrated example) communication units 230-1 and 230-2, an antenna unit 240-1 corresponding to communication unit 230-1, and an antenna unit 240-2 corresponding to communication unit 230-2.

[0029] A combination of the communication unit 230-1 and the antenna unit 240-1, and a combination of the communication unit 230-2 and the antenna unit 240-2 are provided for each band used by the communication device 200. In the example shown in FIG. 4, the combination of the communication unit 230-1 and the antenna unit 240-1 performs data communication using a first link (link1), and the combination of the communication unit 230-2 and the antenna unit 240-2 performs data communication using a second link (link2). Therefore, when the communication device 200 uses three or more bands, additional combinations of communication units and antenna units (not shown) are provided. The communication unit 230-1 and the communication unit 230-2 may control each other and exchange information.

[0030] Since communication unit 230-1 and communication unit 230-2, and antenna unit 240-1 and antenna unit 240-2 have the same configuration, they will be referred to as communication unit 230 and antenna unit 240 below for simplicity.

[0031] The communication unit 230 is composed of a processor such as a microprocessor and a circuit, and includes a memory unit 238, a wireless control unit 231, a data processing unit 232, a modulation / demodulation unit 233, a signal processing unit 234, a channel estimation unit 235, a plurality of wireless interface (IF) units 236-1, ..., 236-N arranged in parallel, and amplifier units 237-1, ..., 237-N connected in series to each of the wireless interface units 236-1, ..., 236-N (where N is an integer of 2 or more). Each of the amplifier units 237-1, ..., 237-N is connected to each of the antenna elements constituting the antenna unit 240 corresponding to the communication unit 230.

[0032] One or more sets of serially connected wireless interface unit 236, amplifier unit 237, and antenna element in antenna unit 240 may be components of communication unit 230. Furthermore, each of wireless interface units 236-1, ..., 236-N may include the function of the corresponding amplifier unit 237-1, ..., 237-N.

[0033] The memory unit 238 temporarily stores data (e.g., transmission data) input from an upper layer of the communication protocol, and provides it to the data processing unit 232. The memory unit 238 also temporarily stores data (e.g., reception data) passed from the data processing unit 232, and provides it to the upper layer of the communication protocol. That is, the memory unit 238 is used as a transmission queue or a reception queue.

[0034] It should be noted that a part or all of the memory unit 238 may be arranged outside the communication unit 230. Furthermore, the memory unit 238-1 arranged in one communication unit 230-1 may be shared with another communication unit 230-2, and the memory unit 238 arranged outside the communication unit 230 may be shared by a plurality of communication units 230-1, 230-2, ....

[0035] During transmission when data is input from an upper layer of its own communication protocol, the data processing unit 232 generates a packet for wireless transmission from the data, performs processing such as adding a header for media access control (MAC) and adding an error detection code, and provides the processed data to the modem unit 233. During reception when input is received from the modem unit 233, the data processing unit 232 performs processing such as analyzing the MAC header, detecting packet errors, and reordering packets, and provides the processed data to the upper layer of its own protocol.

[0036] The wireless control unit 231 controls the exchange of information between the various units in the communication device 200. The wireless control unit 231 also performs parameter setting in the modulation / demodulation unit 233 and the signal processing unit 234, packet scheduling in the data processing unit 232, and parameter setting and transmission power control in the wireless interface unit 236 and the amplifier unit 237.

[0037] During transmission, the modem unit 233 performs encoding, interleaving and modulation processing on input data from the data processing unit 232 based on the encoding method and modulation method set by the radio control unit 231, generates a data symbol stream, and provides it to the signal processing unit 234. During reception, the modem unit 233 performs demodulation processing, deinterleaving and decoding processing on the input symbol stream from the signal processing unit 234, which are the opposite of those during transmission, and provides the data to the data processing unit 232 or the radio control unit 231.

[0038] During transmission, signal processing unit 234 performs signal processing for spatial separation on input from modem unit 233 as necessary, and provides the obtained one or more transmission symbol streams to each of wireless interface units 236-1, .... During reception, signal processing unit 234 performs signal processing on reception symbol streams input from each of wireless interface units 236-1, ..., performs spatial decomposition of the stream as necessary, and provides the resultant streams to modem unit 233.

[0039] The channel estimation unit 235 calculates complex channel gain information of the propagation path from the preamble portion and the training signal portion of the input signal from each of the wireless interface units 236-1, .... The calculated complex channel gain information is used for demodulation processing in the modem unit 233 and spatial processing in the signal processing unit 234 via the wireless control unit 231.

[0040] During transmission, the wireless interface unit 236 converts the input from the signal processing unit 234 into an analog signal, performs filtering, up-conversion to a carrier frequency, and phase control, and sends the signal to the corresponding amplifier unit 237 or antenna unit 240. During reception, the wireless interface unit 236 performs processing such as down-conversion, filtering, and conversion to a digital signal, which is the opposite of that during transmission, on the input from the corresponding amplifier unit 237 or antenna unit 240, and provides data to the signal processing unit 234 and the channel estimation unit 235.

[0041] During transmission, the amplifier unit 237 amplifies an analog signal input from the wireless interface unit 236 to a predetermined power and sends it to a corresponding antenna element in the antenna unit 240. During reception, the amplifier unit 237 performs low-noise amplification of a signal input from a corresponding antenna element in the antenna unit 240 to a predetermined power and outputs it to the wireless interface unit 236.

[0042] At least one of the transmission function and the reception function of the amplifier unit 237 may be included in the wireless interface unit 236. At least one of the transmission function and the reception function of the amplifier unit 237 may be a component other than the communication unit 230.

[0043] A set of wireless interface unit 236 and amplifier unit 237 constitutes one RF (Radio Frequency) branch. It is assumed that one RF branch can transmit and receive signals in one band. In the device configuration example shown in Fig. 4, communication unit 230 includes N RF branches.

[0044] Control unit 210 is composed of a processor such as a microprocessor and a circuit, and controls wireless control unit 231 and power supply unit 220. Control unit 210 may also perform at least a part of the above-mentioned operations of wireless control unit 231 in place of wireless control unit 231. Particularly in this embodiment, control unit 210 and wireless control unit 231 control the operations of each unit to realize operations related to each embodiment described later.

[0045] The power supply unit 220 is configured with a battery power supply or a fixed power supply, and supplies power for driving the communication device 200 .

[0046] The control unit 210 and the communication unit 230 can be configured together as one or more LSIs (Large Scale Integration).

[0047] Also, while communication device 200 is in standby, communication unit 230 may be configured to transition to a standby state or a sleep state (or a state in which at least some functions are stopped) to reduce power consumption. In the device configuration example shown in Fig. 4, communication unit 230 includes N RF branches, but may be configured to transition to a standby state or a sleep state for each RF branch.

[0048] D. Example of operation 1 In this section D, a first operation example of a communication device (MLD) that performs MLO using a first link and a second link will be described. Specifically, the communication device (MLD) transmits an MLP Setup frame over multiple links before the start timing of MLP, and notifies the time (offset) from the transmission timing of the MLP Setup frame to the start timing of MLP and the length of MLP, so that surrounding terminals suppress transmission during a specified period. The operation of the communication device (MLD) that performs MLO, which sets both the first link and the second link to an idle state to facilitate the implementation of MLO by synchronous transmission, will be described below.

[0049] Fig. 5 shows an example of a communication sequence illustrating this operation. However, Fig. 5 assumes a communication system in which a first link (link1) and a second link (link2) are available and one terminal (STA MLD) operates under one access point (AP MLD1). AP MLD1 includes AP1-1 operating on the first link and AP1-2 operating on the second link. STA MLD1 also includes STA1-1 operating on the first link and STA1-2 operating on the second link.

[0050] 5 is the time axis, and shows the communication operations over time on the first link and the second link of the access point and each terminal. Square blocks drawn with solid lines indicate frames to be transmitted, vertical solid arrows indicate frames to be transmitted to their destinations, and square blocks drawn with dotted lines indicate frames to be received.

[0051] First, AP1-1 of AP MLD1 transmits an MLP Setup frame on the first link (link1) at time T1 before the start timing of MLP. Also, AP1-2 of AP MLD1 transmits an MLP Setup frame on the second link (link2) at time T2 before the start timing of MLP, which is different from time T1. Although not shown in the figure, AP1-1 and AP1-2 transmit an MLP Setup frame after completing backoff waiting for a random waiting time on the first link (link1) and second link (LINK2), respectively, and acquiring a period of occupying the channel (for example, TXOP).

[0052] The MLP Setup frame is transmitted to suppress transmission from each terminal during the MLP period. At this time, it is better for the MLP Setup frame to be received by terminals in surrounding OBSSs (Overlapping BSSs). For this reason, the MLP Setup frame is transmitted as a control frame of "01" out of the three classes defined in IEEE802.11.

[0053] The MLP Setup frame describes information about the MLP. The information about the MLP includes, for example, the link on which the MLP is set, the time to start the MLP (the offset from the transmission timing of the frame to the start timing of the MLP), the period and number of times of the MLP, etc. However, details of the MLP Setup frame will be described later.

[0054] In response to receiving an MLP Request frame from a subordinate STA requesting MLP setup, the AP may transmit an MLP Setup frame on each link that performs MLO. However, in Fig. 5, to simplify the drawing, the exchange of MLP Request frames between the STA MLD1 and the AP MLD1 is omitted. The STA transmits an MLP Request frame to the AP to which it is connected when, for example, there is a certain amount of data in its own transmission buffer, or when there is a packet that cannot meet the latency or throughput requirements unless multi-link transmission is performed. The AP MLD and the STA MLD may exchange capability information indicating whether or not the MLP setup is supported in advance at the time of association, etc.

[0055] The MLP Setup frame transmitted by AP1-1 at time T1 contains information on the offset until time T3 when MLP starts, and the MLP duration equivalent to the time from time T3 to time T5. Therefore, when STA1-1 of STA MLD1 receives the MLP Setup frame from AP1-1, it suppresses transmission for the period equivalent to the duration from time T3 to time T5. As a result, the first link (link1) enters an idle state for the period from time T3 to time T5.

[0056] Furthermore, the MLP Setup frame transmitted by AP1-2 at time T2 contains information on the offset until time T4 when MLP starts, and the MLP duration equivalent to the time from time T4 to time T6. Therefore, when STA1-2 of STA MLD1 receives the MLP Setup frame from AP1-2, it suppresses transmission for the period equivalent to the duration from time T4 to time T6. As a result, the second link (link2) enters an idle state for the period from time T4 to time T6.

[0057] AP MLD1 controls the MLP start time and duration to be written in the MLP Setup frame transmitted on each link so that the MLP start time T3 on the first link (link1) is earlier than the MLP end time T6 on the second link (link2), and the MLP start time T4 on the second link (link2) is earlier than the MLP end time T5 on the first link (link1).

[0058] AP MLD1 can set MLP for the period from the latest of the MLP start time of the first link (link1) and the MLP start time of the second link (link2) to the earliest of the MLP end time of the first link (link1) and the MLP end time of the second link (link2) (period T in Figure 5), and during this period AP MLD1 (or a subordinate STA MLD that has sent an MLP Request frame to AP MLD1) can prioritize multi-link transmissions.

[0059] The STA MLD1 that receives an MLP Setup frame from the AP MLD1 suppresses transmission for the period specified by the Duration information from the time specified by the offset information of that frame. However, the STA MLD1 may transmit if it is requested to transmit by receiving a trigger frame from the AP MLD1, etc.

[0060] Also, if the transmission power can be set so that the received power at AP MLD1 when STA MLD1 transmits a signal on each link is equal to or less than a first threshold, STA MLD1 may set the transmission power and then transmit. The first threshold is, for example, a preamble detection threshold. In this case, AP MLD1 may include information about the transmission power in the MLP Setup frame so that STA MLD1 that has received the MLP Setup frame can calculate the received power at AP1-1 and AP1-2 when it transmits a signal.

[0061] At the start of MLP, AP MLD1 may transmit an MLP Setup frame with the MLP duration specified in the Duration / ID field so that legacy terminals that cannot correctly decode the MLP Setup frame can be restrained from transmitting during the MLP.

[0062] In addition, AP MLD1 (or a subordinate STA MLD that has requested AP MLD1 to set MLP) may send an MLP END frame to cancel the MLP set to surrounding terminals if there is no longer a need for multi-link transmission during MLP or if it becomes impossible to set MLP for the same period on each link.

[0063] E. Frame Format This section E describes the formats of the main frames used in the first operation example related to MLO. Figures 6 to 8 show format examples of the MLP Setup frame, MLP Request frame, and MLP End frame, respectively. The information written in the fields included in each frame is described below.

[0064] The Category field describes information that indicates the category of the frame. For example, information that indicates that the frame is a Public Action frame is described.

[0065] The Public Action field describes information indicating that the corresponding frame is a Public Action frame related to MLP settings.

[0066] The Dialog Token field is used to link the relevant frame with the corresponding MLP Request frame, MLP Setup frame, and MLP End frame by writing the same value in the corresponding MLP Request frame, MLP Setup frame, and MLP End frame.

[0067] The Multi-link Period element field includes the following fields: Element ID, Length, Element ID Extension, and Control.

[0068] The Element ID field and the Element ID Extension field contain information indicating that the element is a Multi-link Period element.

[0069] The Control field describes information that distinguishes whether the corresponding frame is an MLP Request frame, an MLP Setup frame, or an MLP End frame.

[0070] The Multi-link Period content field of the MLP Setup frame and the MLP Request frame includes the following fields: Multi-link Period Offset field, Multi-link Period Duration field, Multi-link Period Count field, and Multi-link Link ID field. The Multi-link Period content field of the MLP Setup frame further includes a Status Code.

[0071] The Status Code describes information regarding the result of the MLP setting requested by the Multi-link Request frame (whether the setting is permitted or rejected, etc.).

[0072] The Multi-link Period Offset field describes information about the time to start MLP. The start time may be indicated by absolute time, or may be indicated by relative time information from a certain reference point to the start of MLP. The reference point may be, for example, the next TBTT (Target Beacon Transmission Time). The relative time information is described in granularity such as TU (Time Unit, 1024 microseconds).

[0073] The Multi-link Period Duration field describes information indicating the length of the MLP. The length information is described in units of 32 microseconds, for example.

[0074] The Multi-link Period Count field describes information indicating how many times the corresponding MLP Setup frame has been transmitted. The operation of transmitting the MLP Setup frame multiple times will be described later.

[0075] The Multi-link Period Link ID field describes information about the link for which the MLP is set.

[0076] A communication device (MLD) performing MLO may operate to set up MLP when it receives an MLP Setup frame on at least one of the links in use, regardless of whether it has received an MLP Setup frame on other links. Alternatively, a communication device (MLD) performing MLO may operate to set up MLP only when it receives an MLP Setup frame on all links described in the Multi-link Period Link ID field of the MLP Setup frame. The AP may instruct the subordinate STA which method to use to set up MLP using an MLP Setup frame or the like, or the method may be set when exchanging Capability information related to the setting of MLP at the time of association.

[0077] The AP may negotiate the setting of the Multi-link Period with surrounding APs. At this time, the AP notifies surrounding APs of information about the MLP that it has already sent an MLP Setup frame and set for the subordinate STAs, and information about the MLP that it has not sent an MLP Setup frame but will set in the future, by sending an MLP Advertisement frame.

[0078] An AP that receives an MLP Advertisement frame from another AP returns an MLP Advertisement Response frame indicating whether or not it accepts the contents of each MLP setting described in the received frame. Negotiation of MLP settings may be performed for each link, or negotiation of all link settings may be performed on one link.

[0079] The format of the MLP Advertisement frame is shown in Fig. 9. Description of fields common to the frame formats shown in Figs. 6 to 8 will be omitted here.

[0080] The Number of Reported MLP Reservations field describes the number of MLPs that the AP that transmitted the frame has already transmitted an MLP Setup frame and set up for its subordinate STAs.

[0081] The Number of Pending MLP Reservations field describes the number of MLPs that the AP that transmitted the frame plans to set up in its subordinate STAs by transmitting an MLP Setup frame in the future.

[0082] The Active MLP Reservations field describes information regarding the start time and period of each MLP that the AP that transmitted the frame has already transmitted an MLP Setup frame and set for the subordinate STAs.

[0083] The Pending MLP Reservations field contains information regarding the start time and duration of each MLP that the AP that transmitted the frame plans to set for the STAs under its control in the future.

[0084] In the Active MLP Reservations field and the Pending MLP Reservations field, information regarding the start time and duration of each MLP may be notified, for example, by the TXOP (Transmission Opportunity) Reservation field already defined in the standard. The TXOP Reservation field contains the fields Duration, Service Interval, and Start Time. The Duration field describes information regarding the duration of the MLP. The Service Interval field describes information regarding the time interval from the previous MLP that is set. The START Time field describes information regarding the time to start the MLP. The time information to start the MLP may be indicated as an absolute time, as in the MLP setup frame, or may be indicated as relative time information from a reference point such as the TBTT.

[0085] Fig. 10 shows an example of the format of the MLP Advertisement Response frame. When an AP receives an MLP Advertisement frame from a surrounding AP, it returns an MLP Advertisement Response frame. Descriptions of fields common to the frame formats shown in Figs. 6 to 8 will be omitted here.

[0086] The Status Code field describes information indicating whether or not the setting of each MLP described in the received MLP Advertisement frame is permitted.

[0087] The Schedule Conflict field is provided only when the setting of an MLP is not permitted, and describes information indicating which MLP described in the MLP Advertisement frame is not permitted.

[0088] The Alternate Schedule field is also prepared only when the setting of the MLP is not permitted, and describes information on the start time and period of the MLP that can be set instead of the MLP indicated in the Schedule Conflict field. The Alternate Schedule field may also be described using the TXOP Reservation field, as in the Active MLP Reservations field of the MLP Advertisement frame.

[0089] F. Modification of Operation Example 1 FIG. 11 shows an example of a communication sequence in the first operation example when the MLP start time of the second link is set after the MLP end time of the first link. In FIG. 11, as in the operation example shown in FIG. 5, a communication system in which one terminal (STA MLD) operates under one access point (AP MLD1) is assumed. AP MLD1 includes AP1-1 operating on the first link and AP1-2 operating on the second link. STA MLD1 also includes STA1-1 operating on the first link and STA1-2 operating on the second link. The horizontal axis is the time axis, and shows the communication operations of the access point and each terminal on the first link and the second link for each time. The square blocks drawn with solid lines indicate transmitted frames, the vertical solid arrows indicate frame transmission to the destination, and the square blocks drawn with dotted lines indicate frames that were not transmitted and received frames.

[0090] First, AP1-1 of AP MLD1 transmits an MLP Setup frame on the first link (link1) at time T11 before the start timing of MLP. Then, STA1-1 of STA MLD1 suppresses transmission when time T13 arrives for the period equivalent to the Duration up to time T15, based on the information regarding the MLP start time and duration described in the MLP Setup frame received from AP1-1.

[0091] On the other hand, if AP1-1 fails to send an MLP Setup frame on the second link (link2) within a certain time after sending an MLP Setup frame on the first link (link1), AP1-2 of AP MLD1 will send an MLP Setup frame on the second link (link2) and the MLP start time on the second link (link2) will be later than the MLP end time T15 on the first link (link1). In such a case, it will not be possible to set the time at which the first link (link1) and the second link (link2) are simultaneously in the idle state.

[0092] When AP MLD1 knows that it is not possible to set the time when the first link (link1) and the second link (link2) are simultaneously in the idle state because it is not possible to transmit the MLP Setup frame on the second link (link2) by a certain time, AP MLD1 prevents AP1-2 from transmitting the MLP Setup frame on the second link (link2). Furthermore, AP1-1 may transmit an MLP End frame indicating that MLP has been cancelled in order to prevent surrounding terminals from unnecessarily suppressing transmission due to only the MLP Setup frame on the first link (link1) (i.e., even though MLO is not performed). In the example shown in FIG. 11, AP1-1 transmits the MLP End frame before the MLP start time T13 described in the MLP Setup frame.

[0093] When STA1-1 receives the MLP End frame from AP1-1 and detects that the MLP has been canceled, it can transmit data frames (DATA) without suppressing transmission during the Duration period from time T13 to time T15.

[0094] Alternatively, AP MLD1 may control AP1-2 to transmit an MLP Setup frame on the second link (link2) instead of canceling MLP. In this case, AP1-1 transmits an MLP Setup frame containing information about the appropriate MLP start time and duration on the first link (link1) so that surrounding terminals also suppress transmission on the first link (link1) during the Duration period set on the second link (link2) by this MLP Setup frame.

[0095] G. Operation of communication devices In this section G, the operation of the communication device (MLD) for realizing the above-mentioned first operational example regarding the MLO will be described.

[0096] 12 is a flowchart showing a process performed when a communication device (MLD) operating as an AP sets up an MLP, assuming that the communication device (MLD) has the configuration shown in FIG.

[0097] First, the AP transmits an MLP Advertisement frame (or receives an MLP Advertisement frame from a surrounding AP) and negotiates with the surrounding APs regarding the setting of the Multi-link Period (step S1201). Note that, from the surrounding APs that receive the MLP Advertisement frame, an MLP Advertisement Response frame is returned.

[0098] It is assumed here that the AP has negotiated with surrounding APs and as a result decided to set up the MLP using the first link and the second link.

[0099] Then, when the AP acquires the transmission right in the first link, it transmits an MLP Setup frame in the first link (step S1202).

[0100] Next, when the AP acquires the transmission right in the second link as well, it transmits an MLP Setup frame in the second link at this point in time to check whether MLP can be set up. Specifically, the AP checks whether it is possible to control the MLP start time and period described in the MLP Setup frame transmitted in the second link so that the MLP start time in the second link (corresponding to time T4 in FIG. 5) is earlier than the MLP end time in the first link (corresponding to time T5 in FIG. 5) (step S1203).

[0101] Here, if it is possible to set up the MLP by making the MLP start time on the second link earlier than the MLP end time on the first link (Yes in step S1203), the AP also sends an MLP Setup frame on the second link to cancel the MLP (step S1205), and terminates this processing.

[0102] On the other hand, if the MLP start time on the second link cannot be made earlier than the MLP end time on the first link and MLP cannot be set, the AP also sends an MLP End frame on the first link (step S1205) and terminates this process.

[0103] 13 shows in the form of a flowchart the process performed by a communication device (MLD) operating as an STA (the process for suppressing transmission so that a peripheral terminal can perform MLO). Note that it is assumed that the communication device (MLD) has the configuration shown in FIG.

[0104] When a STA receives an MLP Setup frame from the AP to which it is connected via a first link (step S1301), and then receives an MLP Setup frame via a second link (step S1302), it begins to suppress transmission via the first link and the second link based on the MLP start time and period specified in the MLP Setup frames received via each link (step S1303).

[0105] Thereafter, when the MLP end time based on the contents of the MLP Setup frame received on the first link arrives (Yes in step S1304), the STA releases the transmission suppression on the first link (step S1305).

[0106] Furthermore, when the MLP end time based on the contents of the MLP Setup frame received on the second link arrives (Yes in step S1306), the STA releases the transmission suppression on the second link (step S1307) and terminates this process.

[0107] The operation of the communication device (MLD) shown in FIG. 12 and FIG. 13 can be realized as follows (1) to (4).

[0108] (1) An AP MLD that supports MLP is called an MLP AP MLD, and sets the MLP Support field of the EHT (Extreme High Throughput) Capabilities element that it transmits to 1. If the AP MLD does not support MLP, it sets the MLP Support field to 0.

[0109] (2) A non-AP MLD that supports MLP is called an MLP non-AP MLD, and sets the MLP Support field of the EHT Capabilities element that it transmits to 1. If a non-AP MLD does not support MLP, it sets the MLP Support field to 0.

[0110] (3) An MLP non-AP MLD may request MLP setup from the connected MLP AP MLD. An MLP non-AP MLD requesting MLP setup may send an MLP Request frame indicating the MLP Request subtype in the Control field of the Multi-link Period element. An MLP AP MLD requesting MLP setup sends an MLP Setup frame indicating the MLP Setup subtype in the Control field of the Multi-link Period element. The MLP Setup frame indicates the MLP start time, period, and linkID (see Figure 6).

[0111] (4) When the MLP AP MLD or MLP non-AP MLD determines to set up an MLP, it stops decrementing the backoff counter from the start time of the MLP and resumes decrementing the backoff counter when the MLP ends.

[0112] H. Example of operation 2 In this section H, a second operation example of a communication device (MLD) that performs MLO using a first link and a second link will be described. The communication device (MLD) transmits an MLP Setup frame on multiple links before the start timing of MLP, notifying the time (offset) from the transmission timing of the MLP Setup frame to the start timing of MLP and the length of MLP, and the surrounding terminals suppress transmission during the specified period. In this operation example, the AP transmits an MLP Setup frame multiple times on each link in order to set MLP in surrounding terminals more reliably. At this time, the AP can set MLP for the period during which transmission suppression is set in common to surrounding terminals on each link by all MLP Setup frames transmitted on each link, and can perform multi-link transmission with priority.

[0113] FIG. 14 shows an example of a communication sequence showing this operation. However, in FIG. 14, a communication system is assumed in which a first link (link1) and a second link (link2) are available and one terminal (STA MLD) operates under one access point (AP MLD1). AP MLD1 includes AP1-1 operating on the first link and AP1-2 operating on the second link. STA MLD1 also includes STA1-1 operating on the first link and STA1-2 operating on the second link. The horizontal axis in FIG. 14 is the time axis, and shows the communication operation of the access point and each terminal on the first link and the second link for each time. A square block drawn with a solid line indicates a transmitted frame, a vertical solid line arrow indicates a frame transmission to a destination, and a square block drawn with a dotted line indicates a received frame.

[0114] First, AP1-1 of AP MLD1 transmits the first MLP Setup frame on the first link (link1) at time T1-1, before the start timing of MLP. According to the MLP start time and period information written in the first transmitted MLP Setup frame, MLP starts at time T1-3 and ends at time T1-5. STA1-1 of STA MLD1 successfully receives the first MLP Setup frame and suppresses transmission from time T1-3 to time T1-5, which is specified as the MLP period, so the first link (link1) goes into an idle state.

[0115] Next, AP1-1 of AP MLD1 transmits a second MLP Setup frame on the first link (link1) at time T1-7 before the start timing of MLP. However, STA1-1 of STA MLD1 fails to receive the second transmitted MLP Setup frame, and therefore does not suppress transmission by the second MLP Setup frame.

[0116] Also, AP1-2 of AP MLD1 transmits a first MLP Setup frame on the second link (link2) at time T1-2 before the start timing of MLP. However, STA1-1 of STA MLD1 fails to receive the first transmitted MLP Setup frame, and therefore does not suppress transmission by this MLP Setup frame.

[0117] Next, AP1-2 of AP MLD1 transmits a second MLP Setup frame on the second link (link2) at time T1-4, which is before the start timing of the MLP. The MLP start time and period information written in the second transmitted MLP Setup frame indicates that MLP starts at time T1-6 and ends at time T1-8. STA1-2 of STA MLD1 successfully receives the second MLP Setup frame and suppresses transmission from time T1-6 to time T1-8, which is specified as the MLP period, so the second link (link1) enters an idle state.

[0118] AP MLD1 can set MLP for the period from the latest of the MLP start time of the first link (link1) and the MLP start time of the second link (link2) to the earliest of the MLP end time of the first link (link1) and the MLP end time of the second link (link2) (period T in Figure 14), and during this period AP MLD1 (or a subordinate STA MLD that has sent an MLP Request frame to AP MLD1) can prioritize multi-link transmission.

[0119] In the second operation example, the AP transmits the MLP Setup frame multiple times on each link, so that the MLP is set up more reliably in the surrounding terminals. However, completely different MLPs (with no overlapping periods) may be set up by the MLP Setup frames transmitted by the AP on a certain link. Figure 15 shows an example of a communication sequence in this case.

[0120] In the communication sequence example shown in Fig. 15, AP1-1 of AP MLD1 transmits a first MLP Setup frame on the first link (link1) at time T1-1, which is before the start timing of the MLP. According to the MLP start time and period information written in the first transmitted MLP Setup frame, the MLP starts at time T1-3 and ends at time T1-5. Also, it takes some time for AP1-1 to transmit an MLP Setup frame for the second time on the first link (link1), and the MLP start time set by the second MLP Setup frame is T1-9 and the end time is T1-11.

[0121] Here, if the MLP start time T1-9 set in the second MLP Setup frame is later than the MLP end time T1-5 set in the first transmitted MLP Setup frame, AP1-1 stops transmitting the second MLP Setup frame. This is because transmitting the MLP Setup frame multiple times to specify completely non-overlapping Duration periods does not ensure that surrounding terminals set up MLP, and is therefore pointless.

[0122] AP MLD1 may assume that MLP has been correctly set up in surrounding terminals by the first MLP Setup frame of the first link (link1), for example, if an MLP Setup frame has already been transmitted a certain threshold number of times, and may perform MLO during the MLP period that is assumed to have been set up by an MLP Setup frame transmitted before the first MLP Setup frame.

[0123] Alternatively, if there is a terminal that does not correctly receive the first MLP Setup frame on the first link (link1) and it is assumed that there is a terminal transmitting on the first link (link1) during the MLP period specified in the first MLP Setup frame (in the example shown in FIG. 15, the period from time T1-3 to time T1-5), AP1-1 may send an MLP End frame on the first link (link1) to cancel the MLP set by the terminal that correctly received the first MLP Setup frame.

[0124] For example, if a STA has received an MLP Setup frame linked by the value of the Dialog Token a predetermined number of times or more, and receives an MLP Setup frame that has the same Dialog Token but sets a completely different MLP, the STA may not set the MLP using the MLP Setup frame, but may set the MLP based on the previously received MLP Setup frame. If the STA has not received an MLP Setup frame a predetermined number of times or more, the STA may discard information about past MLP Setup frames.

[0125] I. Effects The advantages brought about by the present disclosure will be summarized below.

[0126] (1) A communication device (MLD) transmits an MLP Setup frame on multiple links on which it wishes to perform MLO. Surrounding terminals set up MLP based on the information contained in the received MLP Setup frame and suppress transmission, making it easier to perform multi-link operation through synchronous transmission.

[0127] (2) APs exchange information about MLP settings by sending and receiving MLP Advertisement frames and MLP Advertisement Response frames with surrounding APs. Therefore, MLP can be efficiently set up between surrounding APs. [Industrial Applicability]

[0128] Although the present disclosure has been described in detail above with reference to specific embodiments, it is obvious that those skilled in the art can modify or substitute the embodiments without departing from the gist of the present disclosure.

[0129] For example, by applying the present disclosure to a wireless LAN system conforming to the IEEE802.11 standard, a communication device (MLD) that implements a multi-link function can easily perform MLO using synchronous transmission, thereby achieving high throughput.

[0130] In short, the present disclosure has been described in the form of examples, and the contents of the specification should not be interpreted as being limited. In order to judge the gist of the present disclosure, the claims should be taken into consideration.

[0131] The present disclosure can also be configured as follows.

[0132] (1) a communication unit that communicates via a plurality of links; A control unit that controls a communication operation by the communication unit; Equipped with The control unit controls to transmit a signal including information regarding a period during which data transmission is to be performed through the plurality of links. Communications equipment.

[0133] (2) The information regarding the period includes at least one of information regarding a start time of the period, a duration of the period, and a link through which transmission is performed during the period; A communication device as described in (1) above.

[0134] (3) the control unit controls to transmit the signal through each link used for the data transmission; A communication device according to any one of (1) or (2) above.

[0135] (4) the control unit controls writing of information regarding a start time of the period and a duration of the period so that the periods overlap in each link used for the data transmission. A communication device according to any one of (1) to (3) above.

[0136] (5) the control unit controls to transmit the signal in response to receiving a signal requesting setting of the period. A communication device according to any one of (1) to (4) above.

[0137] (6) The control unit controls to transmit a signal to cancel the setting of the period. A communication device according to any one of (1) to (5) above.

[0138] (7) the control unit controls to transmit a signal to cancel setting of the periods when the periods cannot overlap each other on each link used for the data transmission; The communication device according to (6) above.

[0139] (8) The control unit controls to transmit a signal for exchanging information regarding the setting of the period. A communication device according to any one of (1) to (7) above.

[0140] (9) In response to receiving the signal to be exchanged, the control unit controls to return a signal including a signal regarding whether or not the period described in the signal to be exchanged is set. The communication device according to (8) above.

[0141] (10) A communication method for a communication device that communicates via a plurality of links, comprising: setting a period during which data transmission is to be performed on the plurality of links; transmitting a signal containing information regarding said period; A communication method comprising:

[0142] (11) a communication unit that performs communication via at least one of the multiple links; A control unit that controls a communication operation by the communication unit; Equipped with the control unit receives a signal including information regarding a period during which data transmission is to be performed on the plurality of links via at least one of the plurality of links, and controls to suppress transmission on the link that received the signal including the information regarding the period. Communications equipment.

[0143] (12) The information regarding the period includes at least one of information regarding a start time of the period, a duration of the period, and a link through which transmission is performed during the period; The communication device according to (11) above.

[0144] (13) The control unit controls to suppress transmission in a link through which the signal is received, based on a start time of the period and a duration of the period described in the signal. The communication device according to (12) above.

[0145] (14) The control unit controls to transmit a signal requesting setting of the period. A communication device according to any one of (11) to (13) above.

[0146] (15) In response to receiving a signal to cancel the setting of the period, the control unit does not suppress transmission based on a signal including information about the period. A communication device according to any one of (11) to (14) above.

[0147] (16) A communication method for a communication device that communicates via a plurality of links, comprising: receiving, on at least one of the plurality of links, a signal including information regarding a period during which data transmission is to be performed on the plurality of links; suppressing transmissions on links receiving a signal containing information about said time period; A communication method comprising: [Explanation of symbols]

[0148] 100: communication system, 110: access point, 120: terminal 200: communication device, 210: control unit, 220: power supply unit 230: communication unit, 231: wireless control unit, 232: data processing unit 233: Modulation / demodulation unit, 234: Signal processing unit, 235: Channel estimation unit 236...wireless interface unit, 237...amplifier unit 238... memory section, 240... antenna section

Claims

1. A communication unit that communicates via a plurality of links, A control unit that controls the communication operation by the communication unit, Comprising, In response to receiving a signal requesting setting of a period during which data transmission is performed via the plurality of links, the control unit controls to transmit a signal including information regarding the period including at least the start time of the period. A communication device.

2. The information regarding the period further includes at least one of the duration of the period and information of at least one of the links for which transmission is performed during the period. The communication device according to Claim 1.

3. The control unit controls to transmit the signal via each link used for the data transmission. The communication device according to Claim 1.

4. The control unit controls the description of information regarding the start time and the duration of the period so that the periods overlap via each link used for the data transmission. The communication device according to Claim 1.

5. The control unit controls to transmit a signal for canceling the setting of the period. The communication device according to Claim 1.

6. When the periods cannot overlap via each link used for the data transmission, the control unit controls to transmit a signal for canceling the setting of the period. The communication device according to Claim 5.

7. The control unit controls to transmit a signal for exchanging information regarding the setting of the period. The communication device according to Claim 1.

8. In response to receiving the signal for exchanging, the control unit controls to return a signal including the approval or disapproval regarding the setting of the period described in the signal for exchanging. The communication device according to Claim 7.

9. A communication method of a communication device that communicates via a plurality of links, comprising: In response to receiving a signal requesting setting of a period during which data transmission is performed via the plurality of links, a step of setting the period; A step of transmitting a signal including information regarding the period including at least the start time of the period. A communication method having the above steps.

10. A communication unit that communicates via at least one of a plurality of links, A control unit that controls the communication operation by the communication unit, Comprising, The control unit controls to transmit a signal requesting setting of a period during which data transmission is performed on the plurality of links, and receives, on at least one of the plurality of links, a signal including information regarding the period including at least the start time of the period, and controls to suppress transmission from the start time on the link that has received the signal including the information regarding the period. Communication device. **Claim 11**: The information regarding the period further includes at least one of the time length of the period and information of at least one of the links on which transmission is performed during the period. The communication device according to claim 10. **Claim 12**: The control unit controls to suppress transmission on the link that has received the signal based on the start time of the period described in the signal and the time length of the period. The communication device according to claim 11. **Claim 13**: In response to receiving a signal for canceling the setting of the period, the control unit does not suppress transmission based on the signal including the information regarding the period. The communication device according to claim 10. **Claim 14**: A communication method for a communication device that communicates via a plurality of links, comprising: transmitting a signal requesting setting of a period during which data transmission is performed on the plurality of links; receiving, on at least one of the plurality of links, a signal including information regarding the period including at least the start time of the period; and suppressing transmission from the start time on the link that has received the signal including the information regarding the period. A communication method having the above steps.

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