Communication device and communication method

Abstract

To provide a communication device for performing multi-link operation by synchronous transmission.SOLUTION: A communication device includes: a communication unit that performs communication by a plurality of links; and a control unit that controls communication operation by the communication unit. The control unit performs control so as to transmit a signal including information related to a period in which data transmission is performed by the plurality of links. The information related to the period includes at least one piece of information of start time of the period, a time length of the period, and a link that performs transmission in the period. The control unit controls description of the information related to the start time of the period and the time length of the period so that the periods overlap in each link used for the data transmission.SELECTED DRAWING: Figure 5

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 for performing wireless communication by bundling a plurality of links.

Background Art

[0002] In recent years, data traffic in wireless communication, such as VR (Virtual Reality) and 8K video transmission, has been increasing. In order to accommodate such traffic, improvement in throughput is required in a wireless LAN (Local Area Network). Currently, as a technology useful for improving throughput, standardization of multi-link operation (MLO) for communicating by bundling a plurality of links is underway.

[0003] MLO can be broadly classified into two types: an asynchronous transmission method in which each link operates independently for communication, and a synchronous transmission method in which transmission timings are completely aligned between links. In MLO, since channels between links are close and leakage occurs, it may be difficult to receive on one link while transmitting on another link. In this case, according to the synchronous transmission method in which transmission timings are aligned among a plurality of links, simultaneous transmission and reception between links do not occur, and the effect of MLO can be obtained.

[0004] When implementing MLO by synchronous transmission, it is required that all links to be used can transmit simultaneously, in other words, that each link simultaneously becomes an idle state. However, terminals that do not support MLO, such as legacy terminals, perform a transmission operation using only one link and independently of other links. For this reason, the time during which all of a plurality of links can be in an idle state and synchronous transmission can be performed is limited, and the effect of throughput improvement by MLO cannot be expected.

[0005] In IEEE 802.11ax, an operation of setting a period called Quiet Time Period (QTP) is standardized. This is an operation of setting a period for suppressing the transmission of other terminals within a BSS (Basic Service Set) so that a terminal can prioritize a certain type of communication. In the QTP operation, first, a terminal that wants to perform a certain type of communication sends a QTP request to the access point, and the access point returns a QTP response to that terminal. Next, when the start timing of the period for suppressing the transmission of other terminals indicated by the QTP request and the QTP response arrives, the access point sends QTP Setup to the surrounding terminals. Terminals other than the sender of the QTP request suppress transmission for a period corresponding to the Duration described in the frame when they receive the QTP Setup. By this, it is possible to prevent communication other than communication between terminals from occurring. However, in order to suppress the transmission of terminals at each link for implementing MLO, it is necessary to send QTP Setup simultaneously across multiple links at that start timing. Since there is a technical problem that simultaneous transmission cannot be performed across multiple links in the first place, it is not possible to realize MLO by synchronous transmission using the QTP operation. Note that a wireless LAN system has been proposed that indicates, by transmitting a frame including a silent element and a silent channel element, that the second subchannel is silent during the silent period, and further indicates the conditions and period during which the first subchannel can be used (see Patent Document 1).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] An object of the present disclosure is to provide a communication device and a communication method for performing MLO by 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 communicates via a plurality of links, a control unit that controls the communication operation by the communication unit, and the control unit controls to transmit a signal including information regarding a period during which data transmission is performed via the plurality of links. It is a communication device.

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

[0010] Moreover, a second aspect of the present disclosure is a communication method of a communication device that communicates via a plurality of links, comprising: a step of setting a period during which data transmission is performed via the plurality of links, a step of transmitting a signal including information regarding the period. It is a communication method having the above.

[0011] Moreover, a third aspect of the present disclosure is 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, and the control unit receives a signal including information regarding a period during which data transmission is performed via the plurality of links via at least one of the plurality of links, and controls to suppress transmission on the link that has 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 the start time of the period, the duration of the period, and information about at least one of the links on which transmission is to be performed during the period. Then, the control unit controls so as to suppress transmission on the link on which the signal is received based on the start time of the period and the duration of the period described in the signal.

[0013] Further, a fourth aspect of the present disclosure is A communication method for a communication device that communicates via a plurality of links, Receiving, on at least one of the plurality of links, a signal including information regarding a period during which data transmission is performed via the plurality of links; Suppressing transmission on the link on which the signal including the information regarding the period is received; A communication method comprising:

Advantages of the Invention

[0014] According to the present disclosure, it is possible to provide a communication device and a communication method that perform MLO by 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. Further, the present disclosure may have additional effects other than the above effects.

[0016] Still other objects, features, and advantages of the present disclosure will become apparent from more detailed descriptions based on the embodiments described below and the accompanying drawings.

Brief Description of the Drawings

[0017]

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DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, the present disclosure will be described in the following order with reference to the drawings. A. Overview B. System Configuration C. Device Configuration D. Operation Example 1 E. Frame Format F. Modification Example of Operation Example 1 G. Operation of Communication Device H. Operation Example 2 I. Effect

[0019] A. Overview In the present disclosure, a terminal that desires to perform synchronous transmission MLO (hereinafter, also simply referred to as "multi-link transmission") or a terminal that has received a request from that terminal transmits a signal (MLP Setup frame) for suppressing the transmission of each terminal during the MLP period to surrounding terminals on a plurality of links before the start timing of the multi-link period (Multi-link Period: MLP) in which MLO is implemented. 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. The terminal that has received the MLP Setup frame suppresses transmission during the specified period. For legacy terminals that do not support the present disclosure, the Duration of the MLP Setup frame is set according to the length of the MLP.

[0020] Therefore, a terminal that attempts multi-link transmission transmits MLP Setup frames 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, transmission by surrounding terminals is suppressed, making it easier to obtain an opportunity for multi-link transmission.

[0021] B. System Configuration FIG. 1 schematically shows a configuration example of a communication system 100 to which the present disclosure is applied. The illustrated communication system 100 includes an access point (AP) 110 and a terminal (STA) 120. The terminal 120 is not an access point, that is, it is a non-AP. In the communication system 100, the first link and the second link can be used, 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), namely an AP MLD and a non-AP MLD, respectively. Hereinafter, unless otherwise specified, when simply referring to "multi-link operation" or MLO, it refers to MLO by synchronous transmission.

[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. Also, 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 they may be connected through three or more links. Also, in FIG. 1, for simplicity of the drawing, only one access point and one terminal are depicted in the communication system 100, but a plurality of access points and terminals may be connected. Also, one or more access points (AP MLDs) and one or more terminals (non-AP MLDs) may be included in one communication device.

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

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

[0026] Band A and band B each contain a plurality of channels. In the examples shown in FIGS. 2 and 3, band A consists of 6 channels and band B consists of 5 channels. MLDs such as the access point 110 and the terminal 120 operating in the communication system 100 select the channels to be used for the first link (link1) and the second link (link2) from among band A and band B. In the example shown in FIG. 2, the 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, the channel to be used for the first link (link1) is selected from band A, and the channel to be used for the second link (link2) is selected from band B.

[0027] C. Device Configuration FIG. 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 the first link (link1) and the second link (link2), that is, an MLD.

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

[0029] The combination of the communication unit 230-1 and the antenna unit 240-1, and the 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, data communication using the first link (link1) is performed by the combination of the communication unit 230-1 and the antenna unit 240-1, and data communication using the second link (link2) is performed by the combination of the communication unit 230-2 and the antenna unit 240-2. Therefore, when the communication device 200 uses three or more bands, combinations of communication units and antenna units (not shown) are further added and provided. The communication unit 230-1 and the communication unit 230-2 may perform control and information exchange with each other.

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

[0031] The communication unit 230 is composed of a processor or a circuit such as a microprocessor, and includes a memory unit 238, a radio 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 parallel radio interface (IF) units 236-1,..., 236-N, and amplifier units 237-1,..., 237-N connected in series to each of the radio interface units 236-1,..., 236-N (where N is an integer of 2 or more). And each of the amplifier units 237-1,..., 237-N is connected to each antenna element constituting the antenna unit 240 corresponding to the communication unit 230.

[0032] One or more sets, each set consisting of a wireless interface unit 236, an amplifier unit 237, and an antenna element in the antenna unit 240 that are connected in series, may be components of the communication unit 230. Further, each wireless interface unit 236-1, …, 236-N may incorporate the functions of the corresponding amplifier units 237-1, …, 237-N, respectively.

[0033] The memory unit 238 temporarily stores data (e.g., transmission data) input from the upper layer of the communication protocol and provides it to the data processing unit 232. Further, the memory unit 238 temporarily stores data (e.g., received data) transferred 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 and a reception queue.

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

[0035] At the time of transmission when data is input from the upper layer of its own communication protocol in the data processing unit 232, a packet for wireless transmission is generated from the data, and further processing such as adding a header for media access control (MAC) and adding an error detection code is performed, and the processed data is provided to the modulation / demodulation unit 233. Also, at the time of reception when there is an input from the modulation / demodulation unit 233 in the data processing unit 232, processing such as analyzing the MAC header, detecting packet errors, and reordering packets is performed, and the processed data is provided to the upper layer of its own protocol.

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

[0037] At the time of transmission, the modulation / demodulation unit 233 performs encoding, interleaving, and modulation processing on the input data from the data processing unit 232 based on the encoding method and modulation method set by the wireless control unit 231, generates a data symbol stream, and provides it to the signal processing unit 234. Also, at the time of reception, the modulation / demodulation unit 233 performs demodulation processing, deinterleaving, and decoding processing opposite to that at the time of transmission on the input symbol stream from the signal processing unit 234, and provides the data to the data processing unit 232 or the wireless control unit 231.

[0038] At the time of transmission, the signal processing unit 234 performs signal processing for spatial separation on the input from the modulation / demodulation unit 233 as necessary, and provides the obtained one or more transmission symbol streams to the respective wireless interface units 236-1,.... Also, at the time of reception, the signal processing unit 234 performs signal processing on the received symbol streams input from the respective wireless interface units 236-1,...., performs spatial decomposition of the streams as necessary, and provides it to the modulation / demodulation unit 233.

[0039] The channel estimation unit 235 calculates complex channel gain information of the propagation path from the preamble part and the training signal part among the input signals from the respective wireless interface units 236-1,.... The calculated complex channel gain information is used for demodulation processing in the modulation / demodulation 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 the carrier frequency, and phase control, and then sends it 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 are opposite to those 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 the analog signal input from the wireless interface unit 236 to a predetermined power and sends it to the corresponding antenna element in the antenna unit 240. During reception, the amplifier unit 237 performs low-noise amplification of the signal input from the corresponding antenna element in the antenna unit 240 to a predetermined power and outputs it to the wireless interface unit 236.

[0042] Note that at least one of the functions during transmission and reception of the amplifier unit 237 may be included in the wireless interface unit 236. Also, at least one of the functions during transmission and reception of the amplifier unit 237 may be a component other than the communication unit 230.

[0043] A set of the wireless interface unit 236 and the amplifier unit 237 constitutes one RF (Radio Frequency) branch. Assume that one RF branch can perform transmission and reception of one band. In the device configuration example shown in FIG. 4, the communication unit 230 is provided with N RF branches.

[0044] The control unit 210 is composed of a processor such as a microprocessor or a circuit, and controls the wireless control unit 231 and the power supply unit 220. Also, the control unit 210 may perform at least a part of the above-described operations of the wireless control unit 231 instead of the wireless control unit 231. Particularly in this embodiment, the control unit 210 and the wireless control unit 231 control the operations of each unit in order to realize the operations according to each of the following embodiments.

[0045] The power supply unit 220 is composed of a battery power supply or a fixed power supply, and supplies driving power to the communication device 200.

[0046] Note that the control unit 210 and the communication unit 230 can be combined and configured by one or more LSIs (Large Scale Integration).

[0047] Also, when the communication device 200 is in standby, the 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, the communication unit 230 includes N RF branches, but each RF branch may be configured to be able to transition to a standby state or a sleep state.

[0048] D. Operation Example 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, before the start timing of the MLP, the communication device (MLD) transmits an MLP Setup frame on a plurality of links, and notifies the time (offset) from the transmission timing of the MLP Setup frame to the start timing of the MLP and the length of the MLP, so that surrounding terminals suppress transmission during the specified period. An operation for making it easier to perform MLO by synchronous transmission with both the first link and the second link in an idle state in a communication device (MLD) that performs MLO will be described below.

[0049] Fig. 5 shows an example of a communication sequence demonstrating this operation. However, Fig. 5 assumes a communication system in which the first link (link1) and the 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. Also, STA MLD1 includes STA1-1 operating on the first link and STA1-2 operating on the second link.

[0050] Note that the horizontal axis in Fig. 5 is the time axis, showing the communication operations for each access point and each terminal on the first and second links at each time. The square blocks drawn with solid lines indicate transmission frames, the solid vertical arrows indicate frame transmission to the destination, and the square blocks drawn with dotted lines indicate reception frames.

[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 the 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 the MLP, which is different from time T1. Although not shown in the figure, AP1-1 and AP1-2 each complete the backoff waiting for a random waiting time on the first link (link1) and the second link (LINK2), and after obtaining a period (e.g., TXOP) to occupy the channel, they transmit the MLP Setup frame.

[0052] The MLP Setup frame is transmitted to suppress the transmission of each terminal during the MLP period. At this time, it is better to make the MLP Setup frame receivable by the terminals of the surrounding OBSS (Overlapping BSS). For this reason, the MLP Setup frame is transmitted as a "01" control frame defined in IEEE802.11.

[0053] The MLP Setup frame describes information about the MLP. Information about the MLP includes, for example, links for setting up the MLP, the time to start the MLP (the offset from the transmission timing of this frame to the start timing of the MLP), the duration and number of times of the MLP, etc. However, details of the MLP Setup frame will be left for later description.

[0054] In response to receiving an MLP Request frame in which a subordinate STA requests MLP settings, the AP may send an MLP Setup frame on each link for performing MLO. However, in FIG. 5, for simplicity of the drawing, the exchange of MLP Request frames between STA MLD1 and AP MLD1 is omitted. The STA sends an MLP Request frame to the destination AP, for example, when there is a certain amount of data or more in its own transmission buffer, or when there are packets that cannot meet latency or throughput requirements without performing multi-link transmission. The AP MLD and the STA MLD may exchange Capablity information indicating whether they support MLP settings in advance at the time of association or the like.

[0055] The MLP Setup frame sent by AP1-1 at time T1 describes the offset until time T3 to start the MLP and information on the duration of the MLP corresponding 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 a period corresponding to the Duration from time T3 to time T5. As a result, the first link (link1) becomes idle for the period from time T3 to time T5.

[0056] In addition, the MLP Setup frame transmitted by AP1-2 at time T2 contains information on the offset until time T4 when the MLP starts and the period of the MLP corresponding 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 a period corresponding to the Duration from time T4 to time T6. As a result, the second link (link2) becomes idle from time T4 to time T6.

[0057] AP MLD1 controls the start time and period of the MLP described 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 the MLP for the period from the latest time among the MLP start time of the first link (link1) and the MLP start time of the second link (link2) to the earliest time among the MLP end time of the first link (link1) and the MLP end time of the second link (link2) (period T in FIG. 5). During this period, AP MLD1 (or the subordinate STA MLD that has transmitted the MLP Request frame to AP MLD1) can give priority to multi-link transmission.

[0059] STA MLD1 that has received the MLP Setup frame from AP MLD1 suppresses transmission for the period specified by the Duration information from the time specified by the offset information of the frame. However, STA MLD1 may perform transmission when requested to transmit, such as by receiving a trigger frame from AP MLD1.

[0060] Also, when 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 the first threshold, STA MLD1 may perform transmission after setting the transmission power. The first threshold is, for example, a preamble detection threshold or the like. At this time, AP MLD1 may describe information regarding the transmission power in the MLP Setup frame so that the received power at AP1-1 and AP1-2 when STA MLD1 that has received the MLP Setup frame transmits a signal can be calculated.

[0061] In order to be able to suppress transmission even between MLPs for legacy terminals that cannot correctly decode the MLP Setup frame, etc., AP MLD1 may transmit an MLP Setup frame in which the MLP period is described in the Duration / ID field at the start of the MLP.

[0062] Also, AP MLD1 (or a subordinate STA MLD that has requested MLP settings from AP MLD1) may transmit an MLP END frame during the MLP to cancel the MLP set for surrounding terminals when it becomes unnecessary to perform multi-link transmission or it becomes impossible to set the same period of MLP on each link.

[0063] E. Frame Format In this section E, the format of the main frames used in the first operation example related to MLO will be described. FIGS. 6 to 8 respectively show format examples of the MLP Setup frame, the MLP Request frame, and the MLP End frame. Hereinafter, the information described in the fields included in each frame will be explained.

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

[0065] In the Public Action field, information indicating that the corresponding frame is a frame related to the MLP setting among the Public Action frames is described.

[0066] In the Dialog Token field, by describing the same value in the corresponding MLP Request frame, MLP Setup frame, and MLP End frame, it is used to associate the corresponding frame with the corresponding MLP Request frame, MLP Setup frame, and MLP End frame.

[0067] The Multi-link Period element field includes each field of Element ID, Length, Element ID Extension, and Control.

[0068] In the Element ID field and the Element ID Extension field, information indicating that it is a Multi-link Period element is described.

[0069] In the Control field, information for distinguishing whether the corresponding frame is an MLP Request frame, an MLP Setup frame, or an MLP End frame is described.

[0070] The Multi-link Period content fields of the MLP Setup frame and the MLP Request frame include each field of Multi-link Period Offset field, Multi-link Period Duration field, Multi-link Period Count field, and Multi-link Link ID. Also, 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 (such as permitting or rejecting the setting) for the MLP setting requested by the Multi-link Request frame.

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

[0073] The Multi-link Period Duration field describes information indicating the length of the MLP. The length information is described with a granularity such as in units of 32 microseconds.

[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 setting the MLP.

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

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

[0078] An AP that has received an MLP Advertisement frame from another AP returns an MLP Advertisement Response frame indicating whether it allows the content of each setting of the MLP described in the received frame. The negotiation regarding the setting of the MLP may be performed for each link, or the negotiation regarding the setting of all links may be executed on one link.

[0079] Figure 9 shows the format of the MLP Advertisement frame. For fields common to the frame formats shown in Figures 6 to 8, the description is omitted here.

[0080] The Number of Reported MLP Reservations field describes the number of MLPs that the AP of the frame's source has already sent MLP Setup frames to configure the subordinate STAs.

[0081] The Number of Pending MLP Reservations field describes the number of MLPs that the AP of the frame's source plans to send MLP Setup frames to configure the subordinate STAs in the future.

[0082] The Active MLP Reservations field describes information regarding the start time and duration of each MLP that the AP of the frame's source has already sent MLP Setup frames to configure the subordinate STAs.

[0083] The Pending MLP Reservations field describes information regarding the start time and duration of each MLP that the AP of the frame's source plans to configure the subordinate STAs 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 Opprotunity) Reservation field that has already been defined in the standard. The TXOP Reservation field has fields for Duration, Service Interval, and Start Time. The Duration field describes the duration information of the MLP. The Service Interval field describes information regarding the time interval from the previously configured MLP. The START Time field describes information regarding the time to start the MLP. Similar to the MLP setup frame, the time information to start the MLP may be indicated by an absolute time, or by relative time information from a reference point such as TBTT.

[0085] Figure 10 shows an example format of the MLP Advertisement Response frame. When the AP receives an MLP Advertisement frame from surrounding APs, it returns an MLP Advertisement Response frame. For fields common to the frame formats shown in FIGS. 6 to 8, the description is omitted here.

[0086] The Status Code field contains information indicating whether or not to allow the settings of each MLP described in the received MLP Advertisement frame.

[0087] The Schedule Conflict field is prepared only when the settings of the MLP are not permitted, and contains information indicating which MLP described in the MLP Advertisement frame cannot be permitted.

[0088] The Alternate Schedule field is also prepared only when the settings of the MLP are not permitted, and contains information regarding the start time and period of the MLP that can be set instead of the MLP indicated by the Schedule Conflict field. Similar to the Active MLP Reservations field of the MLP Advertisement frame, the Alternate Schedule field may also be described using the TXOP Reservation field.

[0089] F. Modification Example of Operation Example 1 FIG. 11 shows an example of a communication sequence in the first operation example where the MLP start time of the second link is set after the MLP end time of the first link. Also in FIG. 11, similar to the operation example shown in FIG. 5, a communication system is assumed in which 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. Also, STA MLD1 includes STA1-1 operating on the first link and STA1-2 operating on the second link. Also, the horizontal axis is the time axis, showing the communication operations at each time on the first and second links of the access point and each terminal. The square blocks drawn with solid lines indicate transmission frames, the solid arrows in the vertical direction indicate frame transmission to the destination, and the square blocks drawn with dotted lines indicate frames 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 the MLP. Then, based on the information regarding the start time and period of the MLP described in the MLP Setup frame received from AP1-1, when time T13 arrives, STA1-1 of STA MLD1 will suppress transmission for a period corresponding to the Duration until time T15.

[0091] On the other hand, if AP1-2 of AP MLD1 fails to transmit an MLP Setup frame on the second link (link2) by a certain time after AP1-1 transmits an MLP Setup frame on the first link (link1), even if AP1-2 transmits an MLP Setup frame on the second link (link2), the MLP start time on the second link (link2) will be after the MLP end time T15 on the first link (link1). In such a case, it becomes impossible to set the time when the first link (link1) and the second link (link2) are simultaneously in the idle state.

[0092] If it is understood that AP MLD1 cannot set the time when the first link (link1) and the second link (link2) are simultaneously in the idle state because it cannot send an MLP Setup frame on the second link (link2) within a certain time, AP1-2 is made not to send an MLP Setup frame on the second link (link2). Further, in order to avoid the surrounding terminals being uselessly suppressed from transmitting by only the MLP Setup frame on the first link (link1) (i.e., even though MLO is not performed), AP1-1 may send an MLP End frame indicating that MLP has been canceled. In the example shown in FIG. 11, AP1-1 sends an MLP End frame before the start time T13 of the MLP described in the MLP Setup frame.

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

[0094] Alternatively, AP MLD1 may not cancel the MLP but control so that AP1-2 sends an MLP Setup frame on the second link (link2). In this case, AP1-1 sends an MLP Setup frame describing information about an appropriate MLP start time and period on the first link (link1) so that the surrounding terminals also suppress transmission on the first link (link1) during the Duration period set by this MLP Setup frame on the second link (link2).

[0095] G. Operation of Communication Device In this item G, the operation of a communication device (MLD) for realizing the above first operation example regarding MLO will be described.

[0096] FIG. 12 shows, in the form of a flowchart, the processing procedure executed when a communication device (MLD) operating as an AP performs MLP settings. However, it is assumed that the communication device (MLD) has the configuration shown in FIG. 4.

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

[0098] Here, it is assumed that as a result of negotiating with the surrounding APs, the AP has determined to perform MLP settings using the first link and the second link.

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

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

[0101] Here, if it is possible to perform the MLP setting by setting the MLP start time at the second link before the MLP end time at the first link (Yes in step S1203), the AP transmits an MLP Setup frame also at the second link to cancel the MLP (step S1205), and ends this process.

[0102] On the other hand, if it is not possible to set the MLP start time at the second link before the MLP end time at the first link and the MLP setting cannot be performed, the AP transmits an MLP End frame also at the first link (step S1205), and ends this process.

[0103] FIG. 13 shows, in the form of a flowchart, a processing procedure executed by a communication device (MLD) operating as an STA (a processing procedure for suppressing transmission in order for a peripheral terminal to perform MLO). However, it is assumed that the communication device (MLD) has the configuration shown in FIG. 4.

[0104] The STA receives an MLP Setup frame at the first link from the destination AP (step S1301), and then, when it receives an MLP Setup frame at the second link (step S1302), starts suppressing transmission at the first link and the second link based on the start time and period of the MLP described in the MLP Setup frames received at each link (step S1303).

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

[0106] Also, when the MLP end time based on the content described in the MLP Setup frame received at the second link arrives (Yes in step S1306), the STA cancels the transmission suppression at the second link (step S1307), and ends this process.

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

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

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

[0110] (3) The MLP non-AP MLD may request the MLP settings from the destination MLP AP MLD. The MLP non-AP MLD that requests the MLP settings may transmit an MLP Request frame indicating that it is the MLP Request subtype in the Control field of the Multi-link Period element. The MLP AP MLD that requests the MLP settings transmits an MLP Setup frame indicating that it is the MLP Setup subtype in the Control field of the Multi-link Period element. The MLP Setup frame indicates the start time, period, and link ID of the MLP (see FIG. 6).

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

[0112] H. Operation Example 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. Before the start timing of the MLP, the communication device (MLD) transmits an MLP Setup frame on a plurality of links, notifies the time (offset) from the transmission timing of the MLP Setup frame to the start timing of the MLP and the length of the MLP, and suppresses transmission by surrounding terminals during the specified period. In this operation example, the AP transmits the MLP Setup frame multiple times on each link in order to more reliably set the MLP for surrounding terminals. At this time, the AP can set the MLP for the period during which transmission suppression is commonly set for surrounding terminals on each link by all the MLP Setup frames transmitted on each link, and can preferentially perform multi-link transmission.

[0113] FIG. 14 shows an example of a communication sequence showing this operation. However, in FIG. 14, it is assumed 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. Also, STA MLD1 includes STA1-1 operating on the first link and STA1-2 operating on the second link. Also, the horizontal axis in FIG. 14 is a time axis, showing the communication operations at each time on the first and second links of the access point and each terminal. The square blocks drawn with solid lines indicate transmission frames, the vertical solid line arrows indicate frame transmission to the destination, and the square blocks drawn with dotted lines indicate received frames.

[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 the MLP. According to the information on the start time and duration of the MLP described in the first transmitted MLP Setup frame, the MLP starts at time T1-3 and ends at time T1-5. Since STA1-1 of STA MLD1 successfully receives the first MLP Setup frame and suppresses transmission during the time from T1-3 to T1-5 specified as the MLP duration, the first link (link1) becomes idle.

[0115] Subsequently, AP1-1 of AP MLD1 performs the second transmission of the MLP Setup frame on the first link (link1) at time T1-7 before the start timing of the MLP. However, since STA1-1 of STA MLD1 fails to receive the second transmitted MLP Setup frame, transmission is not suppressed by the second MLP Setup frame.

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

[0117] Subsequently, AP1-2 of AP MLD1 transmits the second MLP Setup frame on the second link (link2) at time T1-4 before the start timing of the MLP. According to the information on the start time and duration of the MLP described in the second transmitted MLP Setup frame, the MLP starts at time T1-6 and ends at time T1-8. Since STA1-2 of STA MLD1 successfully receives the second MLP Setup frame and suppresses transmission during the time from T1-6 to T1-8 specified as the MLP duration, the second link (link1) becomes idle.

[0118] AP MLD1 can set the MLP for the period from the latest time among the MLP start times of the first link (link1) and the second link (link2) to the earliest time among the MLP end times of the first link (link1) and the second link (link2) (period T in FIG. 14). During this period, AP MLD1 (or the subordinate STA MLD that sent the MLP Request frame to AP MLD1) can give priority to multi-link transmission and send data.

[0119] In the second operation example, the AP sends the MLP Setup frame multiple times on each link to more reliably set the MLP for the surrounding terminals. However, each MLP Setup frame sent by the AP on a certain link can set a completely different MLP (with no overlapping periods). FIG. 15 shows an example of the communication sequence in this case.

[0120] In the communication sequence example shown in FIG. 15, AP1-1 of AP MLD1 sends the first MLP Setup frame on the first link (link1) at time T1-1 before the start timing of the MLP. According to the information on the start time and period of the MLP described in the first MLP Setup frame sent, the MLP starts at time T1-3 and ends at time T1-5. Also, assume that it takes time for AP1-1 to send the second MLP Setup frame on the first link (link1), and the start time of the MLP set by the second MLP Setup frame is T1-9 and the end time is T1-11.

[0121] Here, when the start time T1-9 of the MLP set in the second MLP Setup frame is later than the end time T1-5 of the MLP set in the MLP Setup frame transmitted for the first time, AP1-1 stops transmitting the second MLP Setup frame. This is because even if the MLP Setup frame is transmitted multiple times to specify periods with no overlap at all, it does not ensure that the surrounding terminals can set the MLP correctly, which is a waste of resources.

[0122] For example, when AP MLD1 has transmitted the MLP Setup frame more than a certain threshold number of times, assuming that the MLP has been correctly set by the surrounding terminals with the first MLP Setup frame of the first link (link1), it may perform MLO during the period of the MLP assumed to be set by the MLP Setup frame transmitted before the first MLP Setup frame.

[0123] Or, if there is a terminal that has not correctly received the first MLP Setup frame of the first link (link1) and it is assumed that there is a terminal transmitting on the first link (link1) during the period of the MLP 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 transmit an MLP End frame on the first link (link1) to cancel the MLP set by the terminal that has correctly received the first MLP Setup frame.

[0124] When the STA has received the MLP Setup frame associated with, for example, the value of the Dialog Token more than a predetermined number of times and receives an MLP Setup frame with the same Dialog Token but setting a completely different MLP, it may not perform the MLP setting by the MLP Setup frame and may set the MLP based on the MLP Setup frame received in the past. If the STA has not received the MLP Setup frame more than a predetermined number of times, it may discard the information of the past MLP Setup frame.

[0125] I. Effect Summarize the effects brought about by the present disclosure.

[0126] (1) The communication device (MLD) transmits MLP Setup frames on a plurality of links where it desires to perform MLO. Since surrounding terminals set MLP based on the information described in the received MLP Setup frames and suppress transmission, it becomes easier to perform multi-link operation by synchronous transmission.

[0127] (2) The AP exchanges information regarding the setting of MLP by transmitting and receiving MLP Advertisement frames and MLP Advertisement Response frames with surrounding APs. Therefore, MLP can be efficiently set among surrounding APs.

Industrial Applicability

[0128] As described above, the present disclosure has been described in detail with reference to specific embodiments. However, it is obvious that those skilled in the art can make modifications and substitutions to 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) implementing a multi-link function can easily execute MLO by synchronous transmission and can achieve high throughput.

[0130] In short, the present disclosure has been described in the form of examples, and the description in this specification should not be interpreted restrictively. To determine the gist of the present disclosure, the scope of the claims should be referred to.

[0131] Note that the present disclosure can also have the following configuration.

[0132] (1) A communication unit that communicates on 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 including information regarding a period during which data transmission is performed on the plurality of links, a communication device.

[0133] (2) The information regarding the period includes at least one of information on the start time of the period, the time length of the period, and the link on which transmission is performed during the period. The communication device according to (1) above.

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

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

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

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

[0138] (7) When the periods cannot overlap on 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 (6) above.

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

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

[0141] (10) A communication method of a communication device that communicates via a plurality of links, a step of setting a period for performing data transmission via the plurality of links; a step of transmitting a signal including information about the period; A communication method having the above.

[0142] (11) 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 receives a signal including information about a period for performing data transmission via the plurality of links via at least one of the plurality of links, and controls to suppress transmission in the link that has received the signal including the information about the period. Communication device.

[0143] (12) The information about the period includes at least one of the start time of the period, the duration of the period, and information about at least one of the links for which transmission is to be performed during the period. The communication device according to (11) above.

[0144] (13) The control unit controls to suppress transmission in the link that has received the signal based on the start time of the period and the 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 the setting of the period. The communication device according to any one of (11) to (13) above.

[0146] (15) In response to receiving a signal for canceling the setting of the period, the control unit does not perform suppression of transmission based on a signal including information regarding the period. The 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, at at least one of the plurality of links, a signal including information regarding a period during which data transmission is performed via the plurality of links; suppressing transmission at the link that has received the signal including information regarding the period; A communication method having the above steps.

Explanation of Reference Numerals

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

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 to be exchanged, the control unit controls to return a signal including the approval or disapproval regarding the setting of the period described in the signal to be exchanged. The communication device according to claim 7.

9. A communication method for 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, setting the period; 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 through the plurality of links, and receives, through 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 in the link that has received the signal including the information regarding the period. Communication device.

11. The information regarding the period further includes at least one of the time length of the period and information regarding at least one of the links for which transmission is performed during the period. The communication device according to claim 10.

12. The control unit controls to suppress transmission in the link that has received the signal based on the start time and the time length of the period described in the signal. The communication device according to claim 11.

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.

14. A communication method for a communication device that communicates through a plurality of links, the method including: transmitting a signal requesting setting of a period during which data transmission is performed through the plurality of links; receiving, through 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 in the link that has received the signal including the information regarding the period. A communication method having the above steps.

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