WO2023033184A1 - Dispositif de communication et procédé de communication - Google Patents

Dispositif de communication et procédé de communication Download PDF

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Publication number
WO2023033184A1
WO2023033184A1 PCT/JP2022/033432 JP2022033432W WO2023033184A1 WO 2023033184 A1 WO2023033184 A1 WO 2023033184A1 JP 2022033432 W JP2022033432 W JP 2022033432W WO 2023033184 A1 WO2023033184 A1 WO 2023033184A1
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Prior art keywords
frame
communication device
retransmission
link
links
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PCT/JP2022/033432
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English (en)
Japanese (ja)
Inventor
拓広 佐藤
宏道 留場
淳 白川
良太 山田
秀夫 難波
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シャープ株式会社
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Publication of WO2023033184A1 publication Critical patent/WO2023033184A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
    • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00—Routing or path finding of packets in data switching networks
    • H04L45/24—Multipath
    • H04L45/243—Multipath using M+N parallel active paths
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W28/00—Network traffic management; Network resource management
    • H04W28/02—Traffic management, e.g. flow control or congestion control
    • H04W28/04—Error control
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W28/00—Network traffic management; Network resource management
    • H04W28/02—Traffic management, e.g. flow control or congestion control
    • H04W28/10—Flow control between communication endpoints
    • H04W28/14—Flow control between communication endpoints using intermediate storage
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W72/00—Local resource management
    • H04W72/04—Wireless resource allocation
    • H04W72/044—Wireless resource allocation based on the type of the allocated resource
    • H04W72/0457—Variable allocation of band or rate
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/10—Connection setup
    • H04W76/15—Setup of multiple wireless link connections
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W84/00—Network topologies
    • H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
    • H04W84/10—Small scale networks; Flat hierarchical networks
    • H04W84/12—WLAN [Wireless Local Area Networks]

Definitions

  • the present invention relates to a communication device and communication method.
  • This application claims priority to Japanese Patent Application No. 2021-144568 filed in Japan on September 6, 2021, the content of which is incorporated herein.
  • IEEE The Institute of Electrical and Electronics Engineers Inc.
  • IEEE802.11 a wireless LAN standard
  • IEEE802.11be Standardization of IEEE802.11be, which realizes capacity enhancement, is underway.
  • FEC forward error correction
  • ARQ automatic repeat request
  • Packet errors during decoding are detected by Medium Access Control (MAC) on the receiving side and discarded without being stored in a buffer.
  • An acknowledgment (ACK) is conveyed to the sender if the packet is successfully decoded and a negative acknowledgment (NACK) if a packet error is detected.
  • Packet retransmission processing is performed by ARQ when a NACK is signaled to the sender or no ACK is signaled to the sender within a certain period of time.
  • hybrid ARQ HARQ
  • HARQ hybrid ARQ
  • HARQ the same packet is sent during retransmission, and the packets are combined on the receiving side to improve the signal-to-noise power ratio (SNR) of the received signal.
  • SNR signal-to-noise power ratio
  • Incremental redundancy (IR) combining which increases the error correction decoding capability of the receiving side by newly transmitting a signal), is being studied.
  • Radio frame aggregation is roughly classified into A-MSDU (Aggregated MAC Service Data Unit) and A-MPDU (Aggregated MAC Protocol Data Unit).
  • A-MSDU Aggregated MAC Service Data Unit
  • A-MPDU Aggregated MAC Protocol Data Unit
  • Aggregation of ACKs for example, block ACK (Block Acknowledgment: BA) that can implement reception completion notification for multiple MPDUs, multi STA block ACK (Multi STA Block ACK: BA) that can implement reception completion notification for multiple users M-BA).
  • BA Block Acknowledgment
  • BA Multi STA Block ACK
  • Wi-Fi registered trademark
  • the frequency band (2.4 GHz band, 5 GHz band, 6 GHz band, etc.) to be used according to the use case. It is desirable to appropriately switch sub-channels included in
  • the conventional wireless LAN communication device in order to switch the frequency band used for communication, it was necessary to once disconnect the current frequency band and connect to another frequency band.
  • MLO multi-link operation
  • a communication device can maintain a plurality of connections with different radio resources to be used and settings related to communication. That is, by using MLO, the communication device can simultaneously maintain connections of different frequency bands, so that it is possible to change the frequency band for frame transmission/reception without performing reconnection operation.
  • IEEE802.11be standardization discusses a wireless communication method using a multi-link device (MLD) having two or more links.
  • MLD multi-link device
  • each link constituting a multilink may not be bundled and used at the same time, but may be used independently for frame transmission/reception. For example, by avoiding congested radio channels and selecting an empty link as appropriate for frame transmission, it is possible to reduce the delay and latency that occur during transmission, thereby realizing low-latency communication. be.
  • the characteristics of high-capacity communication and low-delay communication by these multilinks are that the quality of each link (less radio interference between wireless communication devices, high received signal strength, low frame reception error rate, etc.) is enhanced. The point is that the performance of the multilink is improved as much as possible.
  • IEEE802.11-20/0472r2 May. 2020 IEEE802.11-20/1060r1, October. 2020
  • Multi-link Management Entity the entity that manages multi-links (Multi-link Management Entity: MLME) monitors the load of all links (load) and implements load balance, but the existing mechanism does not allow the effect of HARQ in MLD. may not be obtained.
  • MLME Multi-link Management Entity
  • Non-Patent Document 1 a frame having the same Traffic ID (TID) as the frame so that the link does not shift to the Doze state after transmitting the last buffered PPDU frame of the link configuring the MLD. It proposes a mechanism that does not update the field indicating the presence or absence of buffered frames included in the frame until the transmission is completed.
  • Non-Patent Document 2 discusses sharing acknowledgments between all links by MLME.
  • Non-Patent Document 1 and Non-Patent Document 2 also propose an efficient packet combining method in MLD, such as a method of securing a retransmission destination link as an Awake State in advance for frame retransmission. Not yet.
  • the present invention has been made in view of such circumstances, and its object is to realize efficient packet combining in MLD in the IEEE802.11 standard, contributing to low-delay communication and improvement of received SNR.
  • Disclosed is a communication device and a communication method.
  • the communication device and communication method according to the present invention for solving the above problems are as follows.
  • a communication device that transmits frames using two or more links, wherein the communication device selects retransmission destination link candidates according to the load status of each link in the MAC layer.
  • the control unit generates the retransmission destination link candidate and the retransmission method as control information and transmits the retransmission method to the PHY layer, and the communication device includes a transmission unit that generates a frame in the PHY layer, When no acknowledgment for the frame is received, retransmission on a link other than the retransmission destination link candidate specified by the control information is not permitted, and the communication device transmits the frame on the retransmission destination link candidate according to the control information. and a signal demodulator for packet-combining and decoding the frame.
  • control unit does not include retransmission destination link candidates in the control information and sets a retransmission method when each of the links has the same load status.
  • control unit if it does not receive an acknowledgment for the frame on each of the links or does not receive it within a predetermined time, it updates the retransmission destination link candidate;
  • the communication device according to (1) above.
  • control unit When the control unit does not receive an acknowledgment for the frame in succession for a plurality of times in one link in each of the links, or when the frame is not received within a predetermined time, the control unit The communication device according to (1) above, wherein a link with the next lowest load status to the link is included in the candidates for the retransmission destination link.
  • control unit The communication apparatus according to (1) above, wherein control data for setting a NAV for the another link is added to the control information for a predetermined period of time until an acknowledgment for a frame containing the same identifier is received.
  • a signal demodulator that receives a frame using two or more links, assigns retransmission of the frame to the link specified by the control information, and demodulates and decodes the frame;
  • the communication device according to (1) above, wherein packet synthesis of the frame is performed when is set.
  • a communication method for transmitting frames using two or more links comprising a step of selecting retransmission destination link candidates according to the load status of each of the links in the MAC layer. and generating the retransmission destination link candidate and the retransmission method as control information and transmitting it to the PHY layer, the communication method comprising the step of generating a frame in the PHY layer, and receiving an acknowledgment for the frame if not, retransmission is not permitted on any other than the retransmission destination link candidate specified by the control information, and the communication method comprises the step of: receiving the frame on the retransmission destination link candidate according to the control information; and packetizing and decoding frames.
  • the present invention realizes efficient packet combining in MLD according to the IEEE802.11 standard, and improves low-delay communication by improving reception SNR, speeding up user throughput, and features of multilink communication. It contributes to large-capacity communication and low-delay communication.
  • FIG. 1 is a schematic diagram showing an example of division of radio resources according to one aspect of the present invention
  • FIG. FIG. 4 is a diagram showing an example of a frame structure according to one aspect of the present invention
  • FIG. 4 is a diagram showing an example of a frame structure according to one aspect of the present invention
  • FIG. 3 is a diagram illustrating an example of communication according to one aspect of the present invention
  • 1 is a diagram showing one configuration example of a communication system according to one aspect of the present invention
  • FIG. FIG. 3 illustrates frame transmission and reception according to one aspect of the present invention
  • 1 is a block diagram showing one configuration example of a wireless communication device according to one aspect of the present invention
  • FIG. 1 is a block diagram showing one configuration example of a wireless communication device according to one aspect of the present invention
  • FIG. 1 is a block diagram showing one configuration example of a wireless communication device according to one aspect of the present invention
  • FIG. 1 is a block diagram showing one configuration example of a wireless communication device according to one aspect of the present invention
  • FIG. 1 is a block diagram showing one configuration example of a wireless communication device according to one aspect of the present invention
  • FIG. 1 is a schematic diagram illustrating an example of an encoding scheme according to one aspect of the present invention
  • FIG. 1 is a schematic diagram showing an example of a modulation and coding scheme according to one aspect of the present invention
  • FIG. 4 is a schematic diagram illustrating an example of block lengths for LDPC encoding processing according to an aspect of the present invention
  • 1 is a schematic diagram showing an example of a frame retransmission method according to an aspect of the present invention
  • FIG. 1 is a schematic diagram showing an example of a frame retransmission method according to an aspect of the present invention
  • FIG. 1 is a schematic diagram showing an example of a frame retransmission method according to an aspect of the present invention
  • a communication system in this embodiment is called a base station device or an access point device (Access point: AP), and includes a plurality of terminal devices or station devices (Station: STA).
  • a communication system or network composed of access point devices and station devices is called a basic service set (BSS: Basic service set, management range, cell).
  • BSS Basic service set, management range, cell.
  • the station device according to this embodiment can have the function of an access point device.
  • the access point device according to this embodiment can have the functions of the station device. Therefore, hereinafter, when simply referring to a communication device, the communication device can indicate both a station device and an access point device.
  • This embodiment targets the infrastructure mode in which a base station apparatus communicates with a plurality of terminal apparatuses, but the method of this embodiment can also be implemented in an ad-hoc mode in which terminal apparatuses directly communicate with each other.
  • the terminal device forms a BSS on behalf of the base station device.
  • a BSS in ad-hoc mode is also called an IBSS (Independent Basic Service Set).
  • IBSS Independent Basic Service Set
  • a terminal device forming an IBSS in ad-hoc mode can also be regarded as a base station device.
  • the method of the present embodiment can also be implemented in WiFi Direct (registered trademark) in which terminal devices directly communicate with each other.
  • WiFi In Direct a terminal device forms a group instead of a base station device.
  • a terminal device of a group owner that forms a group in WiFi Direct can also be regarded as a base station device.
  • each device can transmit transmission frames of multiple frame types with a common frame format.
  • a transmission frame is defined in a physical (PHY) layer, a medium access control (MAC) layer, and a logical link control (LLC) layer, respectively.
  • the physical layer is also called the PHY layer
  • the MAC layer is also called the MAC layer.
  • a PHY layer transmission frame is called a physical protocol data unit (PPDU: PHY protocol data unit, physical layer frame).
  • PPDU consists of a physical layer header (PHY header) that includes header information for performing signal processing in the physical layer, and a physical service data unit (PSDU: PHY service data unit) that is a data unit processed in the physical layer.
  • PHY header physical layer header
  • PSDU physical service data unit
  • MAC layer frame physical layer frame
  • PSDU can be composed of aggregated MPDU (A-MPDU: Aggregated MPDU) in which multiple MAC protocol data units (MPDU: MAC protocol data units) that are retransmission units in the wireless section are aggregated.
  • MPDU aggregated MPDU
  • the PHY header includes a short training field (STF) used for signal detection and synchronization, a long training field (LTF) used to acquire channel information for data demodulation, etc. and a control signal such as a signal (Signal: SIG) containing control information for data demodulation.
  • STF can be legacy STF (L-STF: Legacy-STF), high-throughput STF (HT-STF: High throughput-STF), or ultra-high-throughput STF (VHT-STF: Very high throughput-STF), high efficiency STF (HE-STF), ultra-high throughput STF (EHT-STF: Extremely High Throughput-STF), etc.
  • LTF and SIG are also L- It is classified into LTF, HT-LTF, VHT-LTF, HE-LTF, L-SIG, HT-SIG, VHT-SIG, HE-SIG and EHT-SIG.
  • VHT-SIG is further classified into VHT-SIG-A1, VHT-SIG-A2 and VHT-SIG-B.
  • HE-SIG is classified into HE-SIG-A1 to 4 and HE-SIG-B.
  • U-SIG Universal SIGNAL
  • the PHY header can include information identifying the BSS that is the transmission source of the transmission frame (hereinafter also referred to as BSS identification information).
  • the information identifying the BSS can be, for example, the SSID (Service Set Identifier) of the BSS or the MAC address of the base station device of the BSS.
  • the information that identifies the BSS can be a value unique to the BSS (for example, BSS Color, etc.) other than the SSID and MAC address.
  • the PPDU is modulated according to the corresponding standard. For example, according to the IEEE 802.11n standard, it is modulated into an Orthogonal Frequency Division Multiplexing (OFDM) signal.
  • OFDM Orthogonal Frequency Division Multiplexing
  • MPDU is a MAC layer header that contains header information etc. for signal processing in the MAC layer, and a MAC service data unit (MSDU: MAC service data unit) that is a data unit processed in the MAC layer or It consists of a frame body and a frame check sequence (FCS) that checks if there are any errors in the frame. Also, multiple MSDUs can be aggregated as an aggregated MSDU (A-MSDU: Aggregated MSDU).
  • MSDU MAC service data unit
  • FCS frame check sequence
  • the frame type of the transmission frame of the MAC layer is roughly classified into three types: a management frame that manages the connection state between devices, a control frame that manages the communication state between devices, and a data frame that contains actual transmission data. Each is further classified into a plurality of types of subframe types.
  • the control frame includes a reception completion notification (ACK: Acknowledge) frame, a transmission request (RTS: Request to send) frame, a reception preparation completion (CTS: Clear to send) frame, and the like.
  • Management frames include Beacon frames, Probe request frames, Probe response frames, Authentication frames, Association request frames, Association response frames, etc. included.
  • the data frame includes a data (Data) frame, a polling (CF-poll) frame, and the like. Each device can recognize the frame type and subframe type of the received frame by reading the contents of the frame control field included in the MAC header.
  • the ACK may include a Block ACK.
  • Block ACK can implement reception completion notification for multiple MPDUs.
  • the ACK may include a Multi STA Block ACK containing reception completion notifications for a plurality of communication devices.
  • a beacon frame contains a field describing the beacon interval and the SSID.
  • the base station apparatus can periodically broadcast a beacon frame within the BSS, and the terminal apparatus can recognize base station apparatuses around the terminal apparatus by receiving the beacon frame. It is called passive scanning that a terminal device recognizes a base station device based on a beacon frame broadcast from the base station device. On the other hand, searching for a base station apparatus by broadcasting a probe request frame in the BSS by a terminal apparatus is called active scanning.
  • the base station apparatus can transmit a probe response frame as a response to the probe request frame, and the description content of the probe response frame is equivalent to that of the beacon frame.
  • connection processing is classified into an authentication procedure and an association procedure.
  • a terminal device transmits an authentication frame (authentication request) to a base station device that desires connection.
  • the base station apparatus Upon receiving the authentication frame, the base station apparatus transmits to the terminal apparatus an authentication frame (authentication response) including a status code indicating whether or not the terminal apparatus can be authenticated.
  • the terminal device can determine whether or not the terminal device is permitted to be authenticated by the base station device. Note that the base station apparatus and the terminal apparatus can exchange authentication frames multiple times.
  • the terminal device transmits a connection request frame to perform the connection procedure to the base station device.
  • the base station apparatus determines whether or not to permit the connection of the terminal apparatus, and transmits a connection response frame to notify that effect.
  • the connection response frame contains an association identifier (AID) for identifying the terminal device, in addition to a status code indicating whether connection processing is possible.
  • the base station apparatus can manage a plurality of terminal apparatuses by setting different AIDs for the terminal apparatuses that have issued connection permission.
  • the base station device and the terminal device After the connection process is performed, the base station device and the terminal device perform actual data transmission.
  • a distributed control mechanism DCF: Distributed Coordination Function
  • PCF centralized control mechanism
  • EDCA enhanced distributed channel access
  • HCF Hybrid coordination function
  • base station equipment and terminal equipment perform carrier sense (CS) to check the usage status of wireless channels around their own equipment prior to communication. For example, when a base station apparatus, which is a transmitting station, receives a signal higher than a predetermined clear channel evaluation level (CCA level: Clear channel assessment level) on the radio channel, the transmission of the transmission frame on the radio channel is performed. put off.
  • CCA level Clear channel evaluation level
  • a state in which a signal of the CCA level or higher is detected in the radio channel is called a busy state, and a state in which a signal of the CCA level or higher is not detected is called an idle state.
  • CCA level is also called a carrier sense level (CS level) or a CCA threshold (CCAT).
  • the base station device performs carrier sense for the frame interval (IFS: Inter frame space) according to the type of transmission frame to be transmitted, and determines whether the radio channel is busy or idle.
  • the period during which the base station apparatus performs carrier sensing differs depending on the frame type and subframe type of the transmission frame to be transmitted by the base station apparatus.
  • IFS Inter frame space
  • the period during which the base station apparatus performs carrier sensing differs depending on the frame type and subframe type of the transmission frame to be transmitted by the base station apparatus.
  • multiple IFSs with different durations are defined.
  • PCF IFS polling frame interval
  • DCF IFS distributed control frame interval
  • the base station apparatus uses DIFS.
  • the base station device After waiting for DIFS, the base station device further waits for a random backoff time to prevent frame collision.
  • a random backoff time called contention window (CW) is used.
  • CSMA/CA assumes that a transmission frame transmitted by a certain transmitting station is received by a receiving station without interference from other transmitting stations. Therefore, if the transmitting stations transmit transmission frames at the same timing, the frames collide with each other and the receiving stations cannot receive the frames correctly. Therefore, each transmitting station waits for a randomly set time before starting transmission, thereby avoiding frame collision.
  • the base station apparatus determines that the radio channel is in an idle state by carrier sense, it starts counting down the CW and acquires the transmission right only when the CW becomes 0, and can transmit the transmission frame to the terminal apparatus. If the base station apparatus determines that the radio channel is busy by carrier sense during the CW countdown, the CW countdown is stopped. Then, when the radio channel becomes idle, following the previous IFS, the base station apparatus resumes counting down remaining CWs.
  • a terminal device which is a receiving station, receives the transmission frame, reads the PHY header of the transmission frame, and demodulates the received transmission frame. By reading the MAC header of the demodulated signal, the terminal device can recognize whether or not the transmission frame is addressed to itself. In addition, the terminal device may determine the destination of the transmission frame based on the information described in the PHY header (for example, the group identification number (GID: Group identifier, Group ID) described in VHT-SIG-A). It is possible.
  • GID Group identifier, Group ID
  • the terminal device When the terminal device determines that the received transmission frame is addressed to itself and demodulates the transmission frame without error, the terminal device transmits an ACK frame indicating that the frame has been correctly received to the base station device, which is the transmitting station. Must.
  • the ACK frame is one of the highest priority transmission frames that is transmitted only waiting for the SIFS period (no random backoff time).
  • the base station apparatus terminates a series of communications upon receiving the ACK frame transmitted from the terminal apparatus.
  • the terminal device cannot receive the frame correctly, the terminal device does not transmit ACK. Therefore, if the base station apparatus does not receive an ACK frame from the receiving station for a certain period of time (SIFS+ACK frame length) after frame transmission, it assumes that the communication has failed and terminates the communication.
  • the end of one communication (also called a burst) in the IEEE 802.11 system is limited to special cases such as the transmission of a notification signal such as a beacon frame, or the use of fragmentation to divide transmission data. Except for this, the determination is always based on whether or not an ACK frame has been received.
  • the network allocation vector (NAV: Network allocation vector).
  • NAV Network allocation vector
  • the terminal device does not attempt communication during the period set in NAV.
  • the terminal device performs the same operation as when the radio channel is determined to be busy by the physical CS for the period set in the NAV. Therefore, communication control by the NAV is also called virtual carrier sense (virtual CS).
  • virtual CS virtual carrier sense
  • NAV is a request to send (RTS) frame introduced to solve the hidden terminal problem, and a clear reception (CTS) frame. to send) frame.
  • RTS request to send
  • CTS clear reception
  • PCF point coordinator
  • the base station apparatus becomes a PC and acquires the transmission right of the terminal apparatus within the BSS.
  • the communication period by PCF includes a contention-free period (CFP: Contention free period) and a contention period (CP: Contention period).
  • CFP contention-free period
  • CP contention period
  • a base station apparatus which is a PC, notifies a beacon frame in which a CFP duration (CFP Max duration) and the like are described within the BSS prior to PCF communication.
  • CFP Max duration CFP duration
  • PIFS is used to transmit the beacon frame notified at the start of PCF transmission, and is transmitted without waiting for the CW.
  • a terminal device that receives the beacon frame sets the period of the CFP described in the beacon frame to NAV.
  • the terminal equipment signals acquisition of the transmission right transmitted from the PC.
  • the right to transmit can only be obtained when a signal (eg a data frame containing a CF-poll) is received. Note that during the CFP period, packet collisions do not occur within the same BSS, so each terminal device does not take the random backoff time used in DCF.
  • the wireless medium can be divided into multiple resource units (RU).
  • FIG. 1 is a schematic diagram showing an example of a division state of a wireless medium.
  • the wireless communication device can divide frequency resources (subcarriers), which are wireless media, into nine RUs.
  • the wireless communication device can divide subcarriers, which are wireless media, into five RUs.
  • the example of resource division shown in FIG. 1 is only an example, and for example, a plurality of RUs can be configured with different numbers of subcarriers.
  • the wireless medium divided as RUs can include spatial resources as well as frequency resources.
  • a wireless communication device can simultaneously transmit frames to a plurality of terminal devices (for example, a plurality of STAs) by arranging frames addressed to different terminal devices in each RU.
  • the AP can write information (Resource allocation information) indicating the division state of the wireless medium in the PHY header of the frame transmitted by the AP as common control information.
  • the AP can describe information (resource unit assignment information) indicating the RU in which the frame addressed to each STA is allocated as unique control information in the PHY header of the frame transmitted by the AP itself.
  • a plurality of terminal devices can transmit frames simultaneously by arranging frames in assigned RUs and transmitting the frames.
  • a plurality of STAs can transmit a frame after waiting for a predetermined period after receiving a frame (Trigger frame: TF) containing trigger information transmitted from the AP.
  • TF Trigger frame
  • Each STA can grasp the RU assigned to itself based on the information described in the TF. Also, each STA can acquire RUs through random access based on the TF.
  • the AP can allocate multiple RUs to one STA at the same time.
  • the plurality of RUs can be composed of continuous subcarriers or discontinuous subcarriers.
  • the AP can transmit one frame using multiple RUs assigned to one STA, or can transmit multiple frames by assigning them to different RUs.
  • At least one of the plurality of frames can be a frame containing common control information for a plurality of terminal devices transmitting resource allocation information.
  • One STA can be assigned multiple RUs by the AP.
  • a STA can transmit one frame using multiple assigned RUs.
  • the STA can use the assigned multiple RUs to assign multiple frames to different RUs and transmit them.
  • the plurality of frames can be frames of different frame types.
  • An AP can allocate multiple AIDs to one STA.
  • the AP can assign RUs to multiple AIDs assigned to one STA.
  • the AP can transmit different frames to multiple AIDs assigned to one STA using the assigned RUs.
  • the different frames can be frames of different frame types.
  • a single STA can be assigned multiple AIDs by the AP.
  • One STA can be assigned RUs for each of the assigned AIDs.
  • One STA recognizes all RUs assigned to multiple AIDs assigned to itself as RUs assigned to itself, and uses the assigned multiple RUs to transmit one frame. can do.
  • one STA can transmit multiple frames using the multiple assigned RUs.
  • information indicating the AID associated with each assigned RU can be described in the plurality of frames and transmitted.
  • the AP can transmit different frames to multiple AIDs assigned to one STA using the assigned RUs.
  • the different frames can be frames of different frame types.
  • base station devices and terminal devices are also collectively referred to as wireless communication devices or communication devices.
  • Information exchanged when one wireless communication device communicates with another wireless communication device is also called data. That is, a wireless communication device includes a base station device and a terminal device.
  • a wireless communication device has either or both of a function to transmit and a function to receive PPDU.
  • FIG. 2 is a diagram showing an example of the configuration of a PPDU transmitted by a wireless communication device.
  • a PPDU that supports the IEEE802.11a/b/g standard has a configuration that includes L-STF, L-LTF, L-SIG and Data frames (MAC frames, MAC frames, payloads, data parts, data, information bits, etc.). be.
  • a PPDU corresponding to the IEEE 802.11n standard has a configuration including L-STF, L-LTF, L-SIG, HT-SIG, HT-STF, HT-LTF and Data frames.
  • PPDU corresponding to the IEEE802.11ac standard includes part or all of L-STF, L-LTF, L-SIG, VHT-SIG-A, VHT-STF, VHT-LTF, VHT-SIG-B and MAC frames. configuration.
  • PPDUs in the IEEE 802.11ax standard are L-STF, L-LTF, L-SIG, RL-SIG with L-SIG temporally repeated, HE-SIG-A, HE-STF, HE-LTF, HE- This configuration includes part or all of SIG-B and Data frames.
  • the PPDU considered in the IEEE802.11be standard is L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, EHT-SIG, EHT-STF, EHT-LTF and part of Data frame or It is an all-inclusive configuration.
  • L-STF, L-LTF and L-SIG surrounded by dotted lines in FIG. collectively referred to as the L-header).
  • a wireless communication device compatible with the IEEE 802.11a/b/g standard can properly receive an L-header in a PPDU compatible with the IEEE 802.11n/ac standard.
  • a wireless communication device conforming to the IEEE802.11a/b/g standard can receive a PPDU conforming to the IEEE802.11n/ac standard as a PPDU conforming to the IEEE802.11a/b/g standard.
  • the wireless communication device compatible with the IEEE802.11a/b/g standard cannot demodulate the PPDU compatible with the IEEE802.11n/ac standard following the L-header, the transmission address (TA: Transmitter Address) , receiver address (RA), and Duration/ID field used for setting NAV cannot be demodulated.
  • TA Transmitter Address
  • RA receiver address
  • Duration/ID field used for setting NAV cannot be demodulated.
  • IEEE 802.11 inserts Duration information into L-SIG as a method for a wireless communication device compatible with IEEE 802.11a/b/g standards to appropriately set NAV (or perform reception operation for a predetermined period). stipulates the method.
  • Information about the transmission rate in L-SIG (RATE field, L-RATE field, L-RATE, L_DATARATE, L_DATARATE field), information about the transmission period (LENGTH field, L-LENGTH field, L-LENGTH) is IEEE802.11a
  • a wireless communication device supporting the /b/g standard is used to properly set the NAV.
  • FIG. 3 is a diagram showing an example of how Duration information is inserted into L-SIG.
  • FIG. 3 shows a PPDU configuration corresponding to the IEEE802.11ac standard as an example, but the PPDU configuration is not limited to this.
  • a PPDU configuration compatible with the IEEE802.11n standard and a PPDU configuration compatible with the IEEE802.11ax standard may be used.
  • TXTIME comprises information on the length of the PPDU
  • aPreambleLength comprises information on the length of the preamble (L-STF+L-LTF)
  • aPLCPHeaderLength comprises information on the length of the PLCP header (L-SIG).
  • L_LENGTH is Signal Extension, which is a virtual duration set for compatibility with the IEEE 802.11 standard; Nops related to L_RATE; It is calculated based on aPLCPServiceLength indicating the number of bits included in the PLCP Service field and aPLCPConvolutionalTailLength indicating the number of tail bits of the convolutional code.
  • the wireless communication device can calculate L_LENGTH and insert it into L-SIG. Also, the wireless communication device can calculate the L-SIG Duration.
  • L-SIG Duration indicates information on the total duration of the PPDU including L_LENGTH and the duration of ACK and SIFS expected to be transmitted from the destination wireless communication device as a response.
  • FIG. 4 is a diagram showing an example of L-SIG Duration in L-SIG TXOP Protection.
  • DATA frame, payload, data, etc.
  • BA is Block ACK or ACK.
  • the PPDU includes L-STF, L-LTF, L-SIG, and may include any or more of DATA, BA, RTS, or CTS.
  • MAC Duration is the period indicated by the value of Duration/ID field.
  • the Initiator can transmit a CF_End frame to notify the end of the L-SIG TXOP Protection period.
  • the wireless communication device that transmits the PPDU should include information for identifying the BSS (BSS color, BSS identification information, value unique to the BSS) in the PPDU. It is preferable to insert, and it is possible to describe information indicating the BSS color in HE-SIG-A.
  • the wireless communication device can transmit L-SIG multiple times (L-SIG Repetition).
  • L-SIG Repetition For example, the radio communication apparatus on the receiving side receives the L-SIG transmitted multiple times using MRC (Maximum Ratio Combining), thereby improving the demodulation accuracy of the L-SIG.
  • MRC Maximum Ratio Combining
  • the wireless communication device can interpret that the PPDU including the L-SIG is a PPDU conforming to the IEEE802.11ax standard.
  • the wireless communication device shall perform the reception operation of a part of the PPDU other than the PPDU (for example, the preamble, L-STF, L-LTF, PLCP header, etc. specified by IEEE 802.11) even during the reception operation of the PPDU. (also called double receive operation).
  • a wireless communication device detects part of a PPDU other than the relevant PPDU during a PPDU reception operation, the wireless communication device updates part or all of the information on the destination address, the source address, the PPDU, or the DATA period. can be done.
  • ACK and BA can also be called responses (response frames). Also, probe responses, authentication responses, and connection responses can be referred to as responses.
  • FIG. 5 is a diagram showing an example of a wireless communication system according to this embodiment.
  • the radio communication system 3-1 includes a radio communication device 1-1 and radio communication devices 2-1 to 2-3.
  • the wireless communication device 1-1 is also called the base station device 1-1, and the wireless communication devices 2-1 to 2-3 are also called terminal devices 2-1 to 2-3.
  • the wireless communication devices 2-1 to 2-3 and the terminal devices 2-1 to 2-3 are also referred to as a wireless communication device 2A and a terminal device 2A as devices connected to the wireless communication device 1-1.
  • the wireless communication device 1-1 and the wireless communication device 2A are wirelessly connected and are in a state of being able to transmit and receive PPDUs to and from each other.
  • the radio communication system may include a radio communication system 3-2 in addition to the radio communication system 3-1.
  • the radio communication system 3-2 includes a radio communication device 1-2 and radio communication devices 2-4 to 2-6.
  • the wireless communication device 1-2 is also called the base station device 1-2, and the wireless communication devices 2-4 to 2-6 are also called terminal devices 2-4 to 2-6.
  • the wireless communication devices 2-4 to 2-6 and the terminal devices 2-4 to 2-6 are also referred to as a wireless communication device 2B and a terminal device 2B as devices connected to the wireless communication device 1-2.
  • the radio communication system 3-1 and the radio communication system 3-2 form different BSSs, this does not necessarily mean that ESSs (Extended Service Sets) are different.
  • ESS indicates a service set forming a LAN (Local Area Network). That is, wireless communication devices belonging to the same ESS can be regarded as belonging to the same network from higher layers. Also, the BSSs are combined via a DS (Distribution System) to form an ESS.
  • Each of the radio communication systems 3-1 and 3-2 can further include a plurality of radio communication devices.
  • the signal transmitted by the radio communication device 2A reaches the radio communication devices 1-1 and 2B, but does not reach the radio communication device 1-2. do. That is, when the radio communication device 2A transmits a signal using a certain channel, the radio communication device 1-1 and the radio communication device 2B determine that the channel is busy, while the radio communication device 1-2 The channel is determined to be idle. It is also assumed that the signal transmitted by the radio communication device 2B reaches the radio transmission device 1-2 and the radio communication device 2A, but does not reach the radio communication device 1-1. That is, when radio communication device 2B transmits a signal using a certain channel, radio communication device 1-2 and radio communication device 2A determine that the channel is busy, while radio communication device 1-1 The channel is determined to be idle.
  • a MLD Multi-link Device
  • An access point device and a station device of this embodiment, which will be described later, are MLDs that support multilink communication.
  • the radio communication devices 1-1, 1-2, 2A, and 2B described above are described as being MLDs, but in actual operation, even if all the radio communication devices in the radio communication system do not support multilink communication, good.
  • the wireless communication device 1-1 base station device 1-1) transmits and the wireless communication device 2-1 (terminal device 2-1) receives.
  • the wireless communication device 2-1 terminal device 2-1
  • the wireless communication device 1-1 base station device 1-1) receives.
  • the device configurations of the wireless communication device 1-1 and the wireless communication device 2-1 are the same as the device configuration examples shown in FIGS. 8 and 9, which will be described later.
  • FIG. 6 shows an example of the overview of the multilink setup of this embodiment.
  • an MLD wireless communication device 1-1 and an MLD wireless communication device 2-1 are used as examples of wireless communication devices compatible with MLD.
  • the MLD radio communication device 1-1 implements procedures for establishing a multilink (a multilink establishment request 10-1 and a multilink establishment response 10-2) to establish a multilink and maintain the multilink. be able to.
  • maintaining multilink means that frames can be transmitted and received based on a predetermined setting for multilink.
  • the MLD radio communication device 1-1 maintains the multilink, and in addition to the procedure for changing the multilink setting (multilink change request 10-3, multilink change response 10-4), It is also possible to carry out a procedure for canceling the multilink using the multilink change request 10-3 and the multilink change response 10-4, thereby canceling the multilink.
  • the MLD wireless communication device 2-1 in FIG. 6 is also called an initiator (multilink initiator), and transmits a multilink establishment request 10-1 to the MLD wireless communication device 1-1.
  • the multilink initiator may be the MLD wireless communication device 1-1 instead of the MLD wireless communication device 2-1.
  • the multilink establishment request 10-1 may include control information such as multilink capability information (Capability information) and multilink operation mode information of its own wireless communication device.
  • the multilink measurement information is the radio signal quality of the frequency band (or channel or subchannel) that can be used by the own radio communication device, and may be included in the multilink establishment request 10-1. and may be reported to the MLD wireless communication device 1-1 using another frame.
  • the radio signal quality is, for example, received power level, SNR (Signal to Noise Ratio), etc., but is not limited to these. Just do it.
  • the object of measurement of the received power level and SNR may be a broadcast frame (announcement frame) such as a beacon transmitted by each sub access point device constituting the MLD wireless communication device 2-1. Since the broadcast frame is broadcast to the wireless communication devices 2A connected to the MLD wireless communication device 1-1, each wireless communication device 2A can measure the wireless signal quality of the same frame, and can check the reception status of each wireless communication device 2A. A relative comparison may be made. In addition to beacons, broadcast and multicast management frames and control frames may also be measured.
  • the measurement of the multilink measurement information is independently performed by the receiving section of the sub wireless communication device (substation device) and transmitted to the upper layer processing section 10001-1.
  • the measured value may be handled for each sub-radio communication device unit, or may be handled by integrating all sub-stations.
  • the number of links forming the MLD wireless communication device 1-1 and the MLD wireless communication device 2-1 is any number of two or more.
  • the carrier frequency of each link can be set to 6 GHz band, 60 GHz band, etc. in addition to 2.4 GHz band and 5 GHz band, but it may change according to the legal regulations of each country.
  • the multilink capability information includes channel information (frequency, bandwidth, etc.) usable by the own wireless communication device, STR (Simultaneously Transmission and Reception) availability, frame synchronization availability, multilink aggregation availability, multilink switching availability, multilink Information such as TXOP (max, min, etc.) may be included.
  • the multilink operation mode information includes channel information (frequency, bandwidth, etc.) of each link that configures the multilink, multilink TXOP limit, multilink aggregation, multilink switch, frame synchronization, frame asynchronization, STR, non-STR, Response frame method (response frame connection information, response frame timing information, etc.), response frame parameters (frame length threshold, response frame transmission time limit, etc.), etc. may be included.
  • the multilink establishment request may be sent independently and separately on each link, or may be sent on one of the links that make up the multilink.
  • the multilink measurement information may be sent independently and separately on each link, or may be sent on one of the links that make up the multilink (multilink in the multilink establishment request). not include link measurement information).
  • the link for transmitting and receiving frames for multilink management is also called a multilink management link (multilink management link).
  • an access point device 20000-1 (hereinafter also referred to as AP-MLD) supporting multilink and a station device 30000-1 (hereinafter also referred to as STA-MLD) supporting multilink
  • multilink consists of a plurality of sub-radio communication devices corresponding to the frequency bands (or channels or sub-channels) of each link that constitutes the .
  • the AP-MLD consists of three sub wireless communication devices, in this case three sub access point devices (20000-2, 200000-3, 20000-4).
  • the STA-MLD is composed of three sub-radio communication devices, in this case three sub-station devices (30000-2, 300000-3, 30000-4).
  • the sub-radio communication device (sub-access point device, sub-station device, etc.) may be composed of a part of the circuits in the radio communication device, and is called a sub-radio communication unit (sub-access point unit, sub-station unit). You may
  • a plurality of sub wireless communication devices are shown as logically separate blocks (squares) for explanation. Physically, it may consist of one wireless communication device. Alternatively, physically, separate sub-wireless communication devices may be configured, each sub-access point device transmitting and receiving necessary information via connections 9-1 and 9-2, and each substation device Necessary information is transmitted and received through connections 9-3 and 9-4.
  • the separate sub-radio communication devices are managed by the MLME.
  • the former case that is, physically composed of one wireless communication device 10-1
  • the configuration of the wireless communication device 10-1 will be described later with reference to FIGS. 8 and 9. .
  • the number of sub-access point devices included in one AP-MLD and the number of sub-station devices included in one STA-MLD change according to the performance installed in each wireless communication device. That is, the number of sub wireless communication devices (sub access point devices, sub station devices) possessed by each wireless communication device positioned within one wireless communication system does not have to match.
  • substation device 30000-2 establishes link 1 by connecting (associating) with subaccess point device 20000-2.
  • Substation device 30000-3 establishes link 2 by connecting (associating) with sub access point device 20000-3.
  • Substation device 30000-4 establishes link 3 by connecting (associating) with sub access point device 20000-4.
  • the number of links forming the multilink is three, but the number is not limited to this and may be any number of two or more.
  • the carrier frequency of link 1 is 2.4 GHz band
  • the carrier frequency of link 2 is 5 GHz band
  • the carrier frequency of link 3 is 6 GHz band.
  • each link can be arbitrarily set from 2.4 GHz band, 5 GHz band, 6 GHz band, 60 GHz band, and other frequency bands, channels, and sub-channels supported by the wireless communication system. , may vary according to the laws and regulations of each country.
  • FIG. 8 shows an example of the device configuration of radio communication devices 1-1, 1-2, 2A and 2B, AP-MLD and STA-MLD (hereinafter also collectively referred to as radio communication device 10-1). It is a diagram.
  • the wireless communication device 10-1 includes an upper layer section (upper layer processing step) 10001-1, an autonomous distributed control section (autonomous distributed control step) 10002-1, a transmitting section (transmitting step) 10003-1, and a receiving section. (Receiving step)
  • This configuration includes 10004-1 and antenna section 10005-1.
  • the upper layer section 10001-1 handles information handled within its own wireless communication device (information related to transmission frames, MIB (Management Information Base), etc.) and frames received from other wireless communication devices, a layer higher than the physical layer, For example, it performs information processing in the MAC layer and the LLC layer.
  • the multilink control section 10001a-1 may be included in the upper layer section 10001-1, or may be independent.
  • the upper layer section 10001-1 measures the load status of the links that have established multilinks in the MAC layer, and the multilink control section 10001a-1 selects retransmission destination link candidates according to the measurement results.
  • the retransmission destination link candidate includes information designating a retransmission destination link for the frame.
  • the multilink control section 10001a-1 generates the retransmission destination link candidate or control information including the retransmission method (ARQ/HARQ) for the retransmission destination link candidate, and transmits the control information to the PHY layer.
  • the multilink control unit 10001a-1 retransmits the frame by ARQ when no retransmission destination link candidate is set in the control information, and when HARQ is set in the control information, the Perform packet combining on candidate retransmission destination links.
  • the load status of each link includes the channel usage status in the MAC layer of the upper layer section 10001-1, the allocation status of frames for each RU (Resource allocation), and the BSS load information indicating the operation status of the AP. ), BSS average access delay, and BSS access category delay.
  • the load status of each link may be the measurement reported by all STAs or STA-MLDs establishing multi-links with the AP-MLD. Instead of the measured value, the link load status may be an identifier that reflects the load status in stages.
  • the upper layer section 10001-1 generates an MPDU or an A-MPDU frame by aggregating the MPDUs from the frame transmitted to the MAC layer.
  • the multilink control unit 10001a-1 implements TID to link mapping for allocating TIDs to the frame and each link. Note that each link can be assigned multiple TIDs.
  • the multilink control unit 10001a-1 transfers the frame to the PHY layer and generates a PPDU including the control information in the PHY header.
  • the PHY header contains information necessary for frame decoding, such as a PLCP preamble for synchronization detection and a PLCP header for determining the modulation and coding scheme (MCS) according to the received signal strength. shall be
  • the transmitting section 10003-1 in the AP-MLD transmits the frame on the link to which the same TID as the PPDU is assigned.
  • the upper layer section 10001-1 is connected to another network and can notify the autonomous distributed control section 10002-1 of information on frames and traffic.
  • Information about traffic may be, for example, control information included in a management frame such as a beacon, or may be measurement information reported by another wireless communication device addressed to the wireless communication device itself.
  • the destination is not limited (it may be addressed to its own device, may be addressed to another device, or may be broadcast or multicast), even if it is control information included in a management frame or control frame. good.
  • FIG. 9 is a diagram showing an example of the device configuration of the autonomous decentralized control unit 10002-1.
  • the control section 10002-1 includes a CCA section (CCA step) 10002a-1, a backoff section (backoff step) 10002b-1, and a transmission determination section (transmission determination step) 10002c-1.
  • CCA step CCA step
  • backoff step backoff step
  • transmission determination section transmission determination step
  • CCA section 10002a-1 receives one or both of information about received signal power received via radio resources and information about received signals (including information after decoding) notified from receiving section 10004-1. can be used to determine the state of the radio resource (including busy or idle determination).
  • the CCA section 10002a-1 can notify the back-off section 10002b-1 and the transmission decision section 10002c-1 of the radio resource state determination information.
  • the backoff unit 10002b-1 can perform backoff using the radio resource state determination information.
  • the backoff unit 10002b-1 generates a Contention Window (CW) and has a countdown function. For example, when the radio resource state determination information indicates idle, the CW countdown can be executed, and when the radio resource state determination information indicates busy, the CW countdown can be stopped.
  • the backoff unit 10002b-1 can notify the transmission determination unit 10002c-1 of the CW value.
  • the transmission decision unit 10002c-1 makes a transmission decision using either one or both of the radio resource status decision information and the CW value. For example, when the radio resource state determination information indicates idle and the value of CW is 0, the transmission determination information can be notified to the transmitting section 10003-1. Further, when the radio resource state determination information indicates idle, the transmission determination information can be notified to the transmitting section 10003-1.
  • the transmission section 10003-1 includes a physical layer frame generation section (physical layer frame generation step) 10003a-1 and a radio transmission section (radio transmission step) 10003b-1.
  • the physical layer frame generation unit 10003a-1 has a function of generating a physical layer frame (hereinafter also referred to as PPDU) based on transmission determination information notified from the transmission determination unit 10002c-1.
  • Physical layer frame generation section 10003a-1 performs error correction coding, modulation, precoding filter multiplication, and the like on a transmission frame sent from an upper layer.
  • the physical layer frame generator 10003a-1 notifies the radio transmitter 10003b-1 of the generated physical layer frame.
  • Control information is included in the frame generated by the physical layer frame generation unit 10003a-1.
  • the control information includes information indicating in which RU (here, RU includes both frequency resources and space resources) data addressed to each wireless communication device is allocated.
  • the frame generated by the physical layer frame generation unit 10003a-1 includes a trigger frame that instructs the wireless communication device, which is the destination terminal, to transmit the frame.
  • the trigger frame contains information indicating the RU used when the wireless communication device instructed to transmit the frame transmits the frame.
  • the radio transmission unit 10003b-1 converts the physical layer frame generated by the physical layer frame generation unit 10003a-1 into a radio frequency (RF) band signal to generate a radio frequency signal. Processing performed by the radio transmission unit 10003b-1 includes digital/analog conversion, filtering, frequency conversion from the baseband band to the RF band, and the like.
  • the receiving section 10004-1 includes a radio receiving section (radio receiving step) 10004a-1 and a signal demodulating section (signal demodulating step) 10004b-1.
  • Receiving section 10004-1 generates information about received signal power from the RF band signal received by antenna section 10005-1.
  • Receiving section 10004-1 can report information on received signal power and information on received signals to CCA section 10002a-1.
  • the receiving section 10004-1 includes a radio receiving section (radio receiving step) 10004a-1 and a signal demodulating section (signal demodulating step) 10004b-1.
  • Receiving section 10004-1 generates information about received signal power from the RF band signal received by antenna section 10005-1.
  • Receiving section 10004-1 can report information on received signal power and information on received signals to CCA section 10002a-1.
  • the radio receiving section 10004a-1 has a function of converting an RF band signal received by the antenna section 10005-1 into a baseband signal and generating a physical layer signal (for example, a physical layer frame).
  • the processing performed by the radio reception unit 10004a-1 includes frequency conversion processing from the RF band to the baseband band, filtering, and analog/digital conversion.
  • the signal demodulator 10004b-1 has a function of demodulating the physical layer signal generated by the radio receiver 10004a-1. Processing performed by the signal demodulator 10004b-1 includes channel equalization, demapping, error correction decoding, and the like.
  • the signal demodulator 10004b-1 can extract, for example, information contained in the physical layer header, information contained in the MAC header, and information contained in the transmission frame from the physical layer signal.
  • the signal demodulation section 10004b-1 can notify the extracted information to the upper layer section 10001-1.
  • the signal demodulator 10004b-1 can extract any or all of the information included in the physical layer header, the information included in the MAC header, and the information included in the transmission frame.
  • the antenna section 10005-1 has a function of transmitting a radio frequency signal generated by the radio transmission section 10003b-1 to radio space. Also, the antenna section 10005-1 has a function of receiving a radio frequency signal and transferring it to the radio receiving section 10004a-1.
  • the wireless communication device 10-1 writes information indicating the period during which the wireless communication device uses the wireless medium in the PHY header or MAC header of the frame to be transmitted, thereby notifying wireless communication devices around the wireless communication device 10-1 of the period.
  • NAV can be set only for a period of time.
  • wireless communication device 10-1 can write information indicating the duration in the Duration/ID field or Length field of the frame to be transmitted.
  • the NAV period set in the wireless communication devices around the own wireless communication device is called the TXOP period (or simply TXOP) acquired by the wireless communication device 10-1. Then, the wireless communication device 10-1 that has acquired the TXOP is called a TXOP holder.
  • the frame type of the frame that is transmitted by the wireless communication device 10-1 to acquire the TXOP is not limited to anything, and may be a control frame (for example, an RTS frame or a CTS-to-self frame) or a data frame. But it's okay.
  • the wireless communication device 10-1 which is a TXOP holder, can transmit frames to wireless communication devices other than its own wireless communication device during the TXOP. If the radio communication device 1-1 is a TXOP holder, the radio communication device 1-1 can transmit frames to the radio communication device 2A within the period of the TXOP. Further, the radio communication device 1-1 can instruct the radio communication device 2A to transmit a frame addressed to the radio communication device 1-1 within the TXOP period. Within the TXOP period, the radio communication device 1-1 can transmit to the radio communication device 2A a trigger frame containing information instructing frame transmission addressed to the radio communication device 1-1.
  • the wireless communication device 1-1 may secure TXOP for all communication bands (for example, operation bandwidth) in which frame transmission may be performed, or a communication band for actually transmitting frames (for example, transmission bandwidth). may be reserved for a specific communication band (Band).
  • the wireless communication device that instructs the frame transmission within the period of the TXOP acquired by the wireless communication device 1-1 is not necessarily limited to the wireless communication device connected to the own wireless communication device.
  • a wireless communication device is not connected to its own wireless communication device in order to transmit a management frame such as a Reassociation frame or a control frame such as an RTS/CTS frame to wireless communication devices around itself.
  • a wireless communication device can be instructed to transmit a frame.
  • TXOP in EDCA which is a data transmission method different from DCF
  • the IEEE802.11e standard is related to EDCA, and defines TXOP from the viewpoint of QoS (Quality of Service) assurance for various services such as video transmission and VoIP.
  • Services are broadly classified into four access categories: VO (VOice), VI (VIdeo), BE (BestEffort), and BK (Back ground).
  • VO VOice
  • VI VI
  • BE BestEffort
  • BK Back ground
  • the order of priority is VO, VI, BE, and BK.
  • Each access category has parameters for the minimum CW value CWmin, maximum value CWmax, AIFS (arbitration IFS), which is a type of IFS, and TXOP limit, which is the upper limit of transmission opportunities. Value is set.
  • CWmin, CWmax, and AIFS of the VO with the highest priority for voice transmission are set to relatively small values compared to other access categories, thereby giving priority to other access categories. Transmission becomes possible. For example, in VI where the amount of data to be transmitted is relatively large due to video transmission, setting a large TXOP limit makes it possible to secure a longer transmission opportunity than in other access categories. Thus, the values of the four parameters of each access category are adjusted for the purpose of guaranteeing QoS according to various services.
  • the signal demodulation section 10004b-1 of the transmission section can perform decoding processing and error detection on the received signal in the physical layer.
  • the decoding processing here includes decoding processing for the error correction code applied to the received signal.
  • the error detection includes error detection using an error detection code (for example, a cyclic redundancy check (CRC) code) assigned in advance to the received signal, or error correction code (for example, a low-density parity code) originally provided with an error detection function. Includes error detection by check code (Low Density Parity Check: LDPC).
  • a decoding process in the physical layer can be applied for each coded block.
  • the upper layer section 10001-1 transfers the decoding result of the physical layer in the signal demodulation section to the MAC layer.
  • the signal of the MAC layer is restored from the transferred decoding result of the physical layer.
  • error detection is performed, and it is determined whether or not the MAC layer signal transmitted by the station device that is the transmission source of the received frame has been correctly restored.
  • FIG. 10 is a diagram showing an example of error correction coding of the physical layer frame generator 10003a-1 according to this embodiment.
  • information bit (systematic bit) sequences are arranged in hatched areas, and redundant (parity) bit sequences are arranged in white areas.
  • Information bits and redundant bits are appropriately bit interleaved.
  • the physical layer frame generator 10003a-1 can read out the necessary number of bits from the allocated bit sequence as the start position determined according to the value of the redundancy version (RV). By adjusting the number of bits, it is possible to flexibly change the coding rate, that is, puncturing.
  • FIG. 10 shows a total of four RVs, RV options are not limited to specific values in the error correction coding according to this embodiment.
  • the error correction coding method according to the present embodiment is not limited to the example of FIG. 10, and any method may be used as long as the coding rate can be changed and decoding processing on the receiving side can be achieved.
  • a generator matrix is obtained from a low-density parity check matrix, and parity bits calculated from the matrix product of the generator matrix and information bits are obtained. Generate.
  • the parity bit is added to the information bit sequence to form a codeword. That is, the physical layer frame generating section 10003a-1 calculates a predetermined information bit length for error correction coding based on at least the size of the parity check matrix set by the coding rate of MCS.
  • An information bit sequence used for LDPC encoding is also called an LDCP information block, and a bit sequence obtained by LDPC-encoding an LDPC information block is also called an LDPC codeword block.
  • FIG. 11 shows an example of associations between MCS, modulation schemes, and coding rates.
  • the modulation scheme is QPSK and the coding rate is 1/2
  • the modulation scheme is 16QAM and the coding rate is 3/4.
  • FIG. 12 shows an example of the association between the coding rate, the LDPC information block length, and the LDPC codeword block length.
  • the LDPC information block length is obtained by multiplying the LDPC codeword block length by the coding rate.
  • candidates for (LDPC information block length, LDPC codeword block length) are (972, 1944), (648, 1296), and (324, 648).
  • the LDPC information block length and the LDPC codeword block length are values determined by the parity check matrix size, and may differ from the transmitted information block length and codeword block length.
  • FIGS. an example of a frame retransmission method during downlink communication is shown in FIGS. Note that acknowledgments corresponding to frames are omitted in both figures.
  • AP-MLD establishes multi-links with STA-MLD with three links and measures the load status of each link. For each link, the upper layer section 10001-1 assigns TID1 and TID3 to link 1, and TID3 to links 2 and 3.
  • FIG. Assume that the frames following PPDU14 and PPDU23 have already been buffered in link 1 and link 2, respectively, and that link 2 has not received an acknowledgment corresponding to PPDU 22 and a frame error has occurred.
  • PPDU 31 indicates the last frame buffered on link 3 .
  • FIG. 13 On the other hand, in FIG.
  • the multilink control unit 10001a-1 selects the link 3 with the lowest load condition as a retransmission destination link candidate based on the load conditions of the links measured by the upper layer unit 10001-1, Generates control information on how to retransmit frames.
  • FIGS. 13 and 14 an outline of a frame retransmission method when the control information includes only retransmission destination link candidates will be described.
  • the AP-MLD transmits the PPDU31 of the last frame buffered on the link 3 and the PPDU22 of the same TID3 following the PPDU31 on the link 2 to the STA-MLD.
  • the AP-MLD retransmits the erroneous PPDU 22 on link 2 with the highest priority using ARQ in the retransmission destination link candidates specified by the control information.
  • the multilink control unit 10001a-1 allows the PPDU 31 to update a field (for example, a More data field) indicating whether or not there is a frame buffered after the frame until the transmission of the PPDU 22 is completed.
  • control data for setting the NAV for link 3, which is a candidate for the retransmission destination link is added to the control information. That is, according to the control information, the AP-MLD retransmits the PPDU 22 of the link 2 with the highest priority by ARQ immediately after the transmission of the PPDU 31 of the link 3 is completed.
  • NAV settings may be, without limitation, RTS, CTS, or CTS-to-self.
  • the multilink control unit 10001a-1 reorders the buffer of the link 3 so that the PPDU22 can be retransmitted prior to the PPDU33. That is, according to the control information, the AP-MLD retransmits the PPDU 22 with the highest priority using ARQ on link 3, which is a candidate for the retransmission destination link.
  • control information includes a retransmission destination link candidate and a retransmission method
  • ARQ/HARQ may be configured for each link.
  • multilink control section 10001a-1 limits retransmission of frames by ARQ and does not limit retransmission of frames by HARQ in the retransmission destination link candidates.
  • AP-MLD retransmits the PPDU 22 with highest priority when the retransmission method is ARQ on link 3, which is a candidate for the retransmission destination link specified by the control information, and the retransmission method is HARQ.
  • the PPDU 22 is retransmitted with the highest priority and packet combining is performed.
  • the multilink control unit 10001a-1 does not allow the PPDU31 to update the field (More data field) indicating the presence or absence of a buffered frame after the frame until the transmission of the PPDU22 is completed. Control data for setting the NAV for link 3, which is a candidate for the retransmission destination link, is added to the control information.
  • the frame may be retransmitted using a different coding rate from the initial transmission.
  • NAV settings may be, without limitation, RTS, CTS, or CTS-to-self. That is, according to the control information, the AP-MLD retransmits the PPDU 22 of the link 2 immediately after the transmission of the PPDU 31 on the link 3 is completed with the highest priority when the retransmission method is ARQ, and the retransmission method is HARQ. If so, retransmit with highest priority and perform packet combining.
  • the multilink control unit 10001a-1 reorders the buffer of link 3 so that PPDU22 can be retransmitted prior to PPDU33.
  • the AP-MLD retransmits the PPDU 22 on link 3, which is a candidate for the retransmission destination link, with the highest priority when the retransmission method is ARQ, and gives the highest priority when the retransmission method is HARQ. retransmit to and perform packet combining.
  • the measurement of the load status of the link may be performed independently by the receiving section of the sub wireless communication device (substation device), or may be performed by integrating all the substations.
  • the measured value of the load status of each link is not limited to a specific index, and may be any value that can be used to determine the load status of the links that constitute the MLD.
  • the MAC layer indicates the frame buffer size allocated to each link, the channel usage status, the frame allocation status for each RU (Resource allocation), and the AP operation status.
  • BSS load information BSS average access delay, BSS access category access delay (BSS Access Category Access Delay), etc.
  • the ratio of Busy in the carrier sense time of each link, or the like may be used as the measurement value.
  • the load status of the plurality of links may be an identifier (Busy, High, Middle, Low, Idle, Null, etc.) that reflects the load status of the links in stages according to a predetermined threshold.
  • a method for selecting retransmission destination link candidates by the multilink control unit 10001a-1 based on the load status of each link measured by the upper layer unit 10001-1 will be described.
  • the multilink control unit 10001a-1 selects the link with the lowest link load status based on the measurement result of the upper layer unit 10001-1, or creates a list of the measurement results in ascending order. Two or more links are elected as resend-to links. Also, when the load conditions of the respective links are the same, the multilink control unit 10001a-1 does not select retransmission destination link candidates. If a frame error occurs in multiple links forming the MLD, the same retransmission destination link may be set for each frame.
  • the upper layer section 10001-1 establishes a new link by transmitting the multilink establishment request 10-1,
  • the link is set as a retransmission destination link candidate, and control information is generated together with the retransmission method.
  • the multilink control unit 10001a-1 When the multilink control unit 10001a-1 according to the present embodiment does not receive an acknowledgment corresponding to a frame within a predetermined time on a link on which a multilink has been established or a retransmission destination link, the multilink control unit 10001a-1 selects retransmission destination link candidates. Update. For example, when another frame has already been buffered on the retransmission destination link, the multilink control unit 10001a-1 sets the link with the next lowest load status included in the retransmission destination link candidates as the retransmission destination link.
  • Another link among the retransmission destination link candidates is retransmitted.
  • Set as destination link For example, if there are two or more candidates for the retransmission destination link, the link with the next lowest link load condition is selected as the retransmission destination link.
  • the link load status according to this embodiment may be measured using a trigger frame.
  • AP-MLD transmits a trigger frame to all wireless communication devices such as STA-MLD that have established multilinks with them.
  • the STA-MLD that received the trigger frame measures the load status of each link and notifies the AP-MLD of the measurement results.
  • the AP- The MLD determines that the load status of the link is Busy and does not set it as a retransmission destination link candidate.
  • the upper layer unit 10001-1 may set an access category for retransmission with a higher priority than the EDCA access category of the IEEE 802.11e standard. good.
  • the multilink control unit 10001a-1 does not permit transmission of frames other than the retransmission-only access category on the retransmission destination link.
  • the STA-MLD receives the frame transmitted from the AP-MLD in the receiving section 10004-1.
  • the signal demodulator 10004b-1 of the STA-MLD can perform decoding processing and error detection on the received signal in the PHY layer.
  • the signal demodulation unit 10004b-1 decodes the PHY header of the PPDU, which is the received transmission frame, performs packet synthesis of the frame when HARQ is set in the PHY header, Decode the word.
  • the decoding result is transferred to the MAC layer in the upper layer section 10001-1.
  • the MAC layer restores the frame of the MAC layer from the forwarded decoding result, performs error detection, and determines whether the frame of the MAC layer transmitted by the station device which is the transmission source of the received frame has been correctly restored. to judge.
  • error detection error detection using an error detection code (for example, a cyclic redundancy check (CRC) code) attached to a received frame, or error correction code originally provided with an error detection function (for example, a low density parity check code (LDPC )) includes error detection.
  • the decoding processing here includes decoding processing for the error correction code applied to the received signal.
  • a decoding process in the PHY layer can be applied for each coded block.
  • the signal demodulation unit 10004b-1 does not perform packet synthesis of the frame in the decoding process, decodes the codeword of the PPDU, and outputs the decoding result. It is transferred to the upper layer section 10001-1.
  • the communication device maintains the retransmission function of the MAC layer, reduces the overhead of the PHY layer and the MAC layer, and enables effective packet combining in the PHY layer. It can contribute to improvement of transmission efficiency.
  • the communication device can communicate in a frequency band (frequency spectrum) called an unlicensed band that does not require a license from a country or region. is not limited to this.
  • the communication device according to the present invention is, for example, a white band that is not actually used for the purpose of preventing interference between frequencies, even though the country or region has given permission to use it for a specific service.
  • the frequency band called for example, the frequency band allocated for television broadcasting but not used in some areas
  • the shared spectrum shared frequency band
  • the program that operates in the wireless communication device is a program that controls the CPU and the like (a program that causes a computer to function) so as to implement the functions of the above-described embodiments related to the present invention.
  • Information handled by these devices is temporarily stored in RAM during processing, then stored in various ROMs and HDDs, and read, modified, and written by the CPU as necessary.
  • Recording media for storing programs include semiconductor media (eg, ROM, nonvolatile memory cards, etc.), optical recording media (eg, DVD, MO, MD, CD, BD, etc.), magnetic recording media (eg, magnetic tapes, flexible disk, etc.).
  • the program when distributing to the market, can be distributed by storing it in a portable recording medium, or it can be transferred to a server computer connected via a network such as the Internet.
  • the storage device of the server computer is also included in the present invention.
  • part or all of the communication device in the above-described embodiments may be typically implemented as an LSI, which is an integrated circuit.
  • Each functional block of the communication device may be individually chipped, or part or all of them may be integrated and chipped. When each functional block is integrated, an integrated circuit control unit for controlling them is added.
  • the method of circuit integration is not limited to LSIs, but may be realized with dedicated circuits or general-purpose processors.
  • the method of circuit integration is not limited to LSIs, but may be realized with dedicated circuits or general-purpose processors.
  • a technology for integrating circuits to replace LSIs emerges due to advances in semiconductor technology, it is possible to use an integrated circuit based on this technology.
  • the wireless communication device of the present invention is not limited to application to mobile station devices, but can be applied to stationary or non-movable electronic devices installed indoors and outdoors, such as AV equipment, kitchen equipment, cleaning/washing equipment, etc. Needless to say, it can be applied to equipment, air conditioners, office equipment, vending machines, and other household equipment.
  • the present invention is suitable for use in communication devices and communication methods.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

La présente invention concerne un dispositif de communication sans fil qui transmet une trame à l'aide de deux liaisons ou plus. Le dispositif de communication est pourvu d'une unité de commande à liaisons multiples pour sélectionner un candidat de liaison de destination de retransmission en fonction de l'état de charge de chacune des liaisons dans une couche MAC. L'unité de commande génère et envoie des informations de commande concernant le candidat de liaison de destination de retransmission et un procédé de retransmission à une couche PHY. Si une réponse affirmative par rapport à la trame n'est pas reçue, l'unité de commande ne permet pas la retransmission autre que par le candidat de liaison de destination de retransmission désigné par les informations de commande. Selon la norme IEEE802.11, la présente invention permet une combinaison de paquets dans un dispositif à liaisons multiples, et contribue à la réduction de la latence et à une amélioration du S/B de réception.
PCT/JP2022/033432 2021-09-06 2022-09-06 Dispositif de communication et procédé de communication WO2023033184A1 (fr)

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JPH0955776A (ja) * 1995-08-11 1997-02-25 Kokusai Denshin Denwa Co Ltd <Kdd> パケット通信装置
WO2017043195A1 (fr) * 2015-09-11 2017-03-16 ソニー株式会社 Dispositif de communication sans fil, procédé de communication sans fil et système de communication sans fil
WO2020032664A1 (fr) * 2018-08-10 2020-02-13 엘지전자 주식회사 Procédé et dispositif de commande d'une pluralité de liaisons dans un système de réseau local sans fil prenant en charge une pluralité de liaisons
WO2020217704A1 (fr) * 2019-04-23 2020-10-29 ソニー株式会社 Dispositif de communication et procédé de communication
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JPH0955776A (ja) * 1995-08-11 1997-02-25 Kokusai Denshin Denwa Co Ltd <Kdd> パケット通信装置
WO2017043195A1 (fr) * 2015-09-11 2017-03-16 ソニー株式会社 Dispositif de communication sans fil, procédé de communication sans fil et système de communication sans fil
WO2020032664A1 (fr) * 2018-08-10 2020-02-13 엘지전자 주식회사 Procédé et dispositif de commande d'une pluralité de liaisons dans un système de réseau local sans fil prenant en charge une pluralité de liaisons
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