Method and apparatus for multi-user direct link transmission

Abstract

Aspects of the disclosure generally relate to multi-user (MU) point-to-point (P2P) protocols in wireless networks. A first station (STA) can receive an allocation of resource units (RUs) from an access point (AP) for point-to-point (P2P) communications; transmit a first frame to a second peer STA on a first portion of the allocated P2P RUs; and receive a second frame transmitted by the second STA on a second portion of the P2P RUs allocated to the first STA by the AP.

Description

Technical Field

[0001] This invention generally relates to wireless communication. Background Technology

[0002] Wireless communication networks are widely deployed to provide various communication services, such as voice, video, packet data, messaging, and broadcasting. These wireless networks can be multiple access networks capable of supporting multiple users by sharing available network resources. Examples of such multiple access networks include Code Division Multiple Access (CDMA) networks, Time Division Multiple Access (TDMA) networks, Frequency Division Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA) networks, and Single Carrier FDMA (SC-FDMA) networks.

[0003] To address the challenges of increased bandwidth and reduced latency requirements in wireless communication systems in high-density environments, multi-user (MU) schemes are being developed to allow a single access point to schedule multiple simultaneous transmissions to or from non-AP stations within a wireless network. For example, the Institute of Electrical and Electronics Engineers (IEEE) has already adopted one such MU scheme in draft version 6.0 (D6.0) of the 802.11ax standard in November 2019.

[0004] Due to the characteristics of MU, a station has the opportunity to gain access to the wireless medium through two access schemes: the MU scheme and the traditional Enhanced Distributed Channel Access (EDCA (Single User) scheme).

[0005] The 802.11ax standard allows MU downlink (DL) transmissions to be performed by an Access Point (AP), where the AP can perform multiple simultaneous basic transmissions to various non-AP stations through so-called Resource Units (RUs). As an example, a Resource Unit, for instance, splits the communication channels of a wireless network in the frequency domain based on Orthogonal Frequency Division Multiple Access (OFDMA) technology. The assignment of a non-AP station to a station is signaled at the beginning of the MU downlink frame by providing each RU with an Association Identifier (AID) for the non-AP station (which is obtained individually by each station during its association process with the AP) defined in the transmission opportunity.

[0006] The 802.11ax standard also allows AP-triggered MU uplink (UL) transmissions, where various non-AP stations can simultaneously transmit to the AP using resource units used to form MU UL transmissions. To control MU UL transmissions by non-AP stations, the AP sends a control frame (called a trigger frame (TF)) in which the AP allocates resource units to non-AP stations using the 16-bit Association Identifier (AID) assigned to them upon registration with the AP and / or using a reserved set of AIDs for each non-AP station.

[0007] The 802.11ax MU transmission scheme used is not suitable for high-bandwidth communication services, such as video-based services like gaming, virtual reality, and streaming applications. This is because all communication goes through the access point (AP), which doubles the airtime used for transmission and also doubles the number of media accesses (and therefore the media access time).

[0008] The 802.11 network protocol's single-user (SU) scheme allows direct link (DiL, also known as point-to-point (P2P) transmission), where data (MAC) frames are addressed using the destination station's 48-bit IEEE MAC address. However, SU and MU schemes directly compete with each other for access to the wireless medium (for MU, this is done by the access point (AP); for SU, it's done by non-AP stations). In high-density environments, this competition generates numerous unwanted collisions, reducing latency and overall usable data throughput.

[0009] Integrating P2P communication under a global policy for AP scheduling could be considered. However, this presents some challenges because the AP must manage both data transmission from non-AP stations to peer non-AP stations and data transmission from peer non-AP stations back to non-AP stations.

[0010] More generally, 802.11 is considered unsuitable for point-to-point transmission and can improve conventionally specified MU transmission. Summary of the Invention

[0011] The broad objective of this invention is to improve this situation.

[0012] The inventors have considered using an Access Point (AP) as a central point for scheduling resource units and a source peer as a means of knowing the need to communicate with the destination peer. In embodiments of the invention, the source station is responsible for sharing bandwidth with the destination peer that has an established direct link session with the source station on the resources allocated to the source station by the AP.

[0013] Some aspects of the present invention provide a method for wireless communication, comprising performing the following steps at a first station (STA):

[0014] The first STA receives the allocation of resource units (RUs) from the access point (AP) for direct link (DiL) communication.

[0015] Transmit the first frame to the peer second STA on the first part of the allocated DiL RU; and

[0016] The second frame transmitted by the second STA is received on the second part of the DiL RU allocated by the AP to the first STA.

[0017] Therefore, the management of point-to-point communication is distributed between the AP, which has global control over resource scheduling at the BSS level (e.g., through arbitration between UL, DL, and DiL requirements), and a peer STA, which manages the allocated P2P resource units (e.g., through subleasing or time-sharing resources with the corresponding peer STA). This results in efficient and simple resource management, especially for direct link communication.

[0018] A preferred implementation is when the first and second portions are time-division multiplexed and separated by short inter-frame intervals (SIFS).

[0019] In this way, the transmission of the second frame occupying the second part of the allocated RU begins exactly after the SIFS following the end of the transmission of the first frame occupying the first part, preventing the medium from being preempted by a transmission from another STA that has not set its NAV after the end of the transmission of the first frame.

[0020] Specifically, the transmission of the first frame is configured such that the end of the transmission of the second frame by the second STA is time-aligned with the end of the allocated DiL RU.

[0021] This allows the AP to regain control of the medium after the allocated DiL RU expires, without interference from other stations. In fact, if the transmission of the second frame ends before the time allocated by the AP for point-to-point communication has elapsed, a station that has not yet set up NAV may preempt the medium and begin transmission.

[0022] In one implementation, the second frame is a response frame to the first frame.

[0023] For example, the second frame is an acknowledgment (ACK) frame sent by the second STA to confirm receipt of the first frame.

[0024] According to an embodiment, configuring the transmission of the first frame includes setting the length of the first frame such that the remaining time for the second part of the DiL RU (i.e., the duration from one SIFS after the end of the transmission of the first frame until the end of the allocated DiL RU) matches the transmission time of the second frame.

[0025] This allows DiL communication to occupy the entire duration of the allocated DiL RU without requiring specific signal notification from the first STA to the second STA. This can be achieved when the length of the second frame is known or predictable to the first STA, such as when the second frame embodies an immediate acknowledgment of the first frame.

[0026] In one implementation, setting the length of the first frame includes:

[0027] Based on the time of transmitting the second frame, calculate the time TXTIME1 that can be used by the first STA to transmit Physical Protocol Data Units (PPDUs) including the first frame; and

[0028] The length of the first frame is derived based on the obtained time TXTIME1 and at least one transmission parameter used to transmit the first frame, such as a modulation and coding scheme (MCS).

[0029] Wherein, TXTIME1 is calculated as TXTIME0 - TXTIME2 - SIFS, where:

[0030] TXTIME0 is the duration of the RU allocated by the AP for DiL communication, and

[0031] TXTIME2 is the time required for the second STA to transmit the Physical Protocol Data Unit (PPDU) including the second frame.

[0032] According to an embodiment, configuring the transmission of the first frame includes: including a reverse (RD) permission addressed to the second STA in the first frame, the RD permission allowing the second STA to transmit the second frame to the first STA in the reverse direction.

[0033] In one implementation, the first frame contains a control field that indicates a reverse permission (RDG) bit that is set to 1 to indicate that the receiving second STA is allowed to transmit the second frame to the first STA in the reverse direction.

[0034] In the variant, the RDG control field is transmitted to the second STA using a QoS (Quality of Service) - Null frame.

[0035] In another variation, a data frame is used to transmit the RDG control field to the second STA.

[0036] In one implementation, configuring the transmission of the first frame also includes including the duration within the first frame that permits the second STA to transmit the second frame.

[0037] Specifically, the duration included in the first frame is set to the maximum time available for transmission, starting from one SIFS after the end of the first frame transmission until the end of the allocated DiL RU.

[0038] The duration is set, which allows the second STA to occupy the permitted second portion of the DiL resource unit. In one implementation, the second STA is also required to send frames in the reverse direction, even if there is no or insufficient data available for transmission by the second STA (e.g., by padding the second frame).

[0039] In one implementation, the duration included in the first frame is set to be equal to the value of TXTIME0-TXTIME1-SIFS, where:

[0040] TXTIME0 is the duration of the RU allocated by the AP for DiL communication, and

[0041] TXTIME1 is the time required for the first STA to transmit the Physical Protocol Data Unit (PPDU) including the first frame.

[0042] According to an embodiment, the allocation of the DiL RU and the length of the DiL RU are included in the trigger frame received from the AP.

[0043] In one implementation, the allocation of the DiL RU and the length of the DiL RU are included in the Triggered Resource Scheduling (TRS) field of the data or control frame received from the AP.

[0044] Specifically, the allocation indicates the center frequency of the DiL RU and the frequency bandwidth of the Physical Protocol Data Units (PPDUs) to be transmitted on the DiL RU.

[0045] In one implementation, the time TXTIME0 allocated by the AP for transmitting the PPDU on the DiL RU is obtained based on the length or number of data symbols of the DiL RU and at least one transmission parameter specified by the AP, such as a modulation and coding scheme (MCS).

[0046] Some other aspects of the present invention provide a method for wireless communication, comprising performing the following steps at a first station (STA):

[0047] During a transmission opportunity (TXOP) set by an access point (AP), the allocation of a first resource unit (RU) to the first STA is received from the AP for use in direct link (DiL) communication;

[0048] Determine whether the AP schedules the allocation of the second RU to the first STA for DiL communication during the TXOP period;

[0049] Based on the determination, the configuration is to transmit a first frame to the peer second STA on a portion or all of the first DiL RU; and

[0050] The configured first frame is transmitted from the first DiL RU to the second STA.

[0051] According to an embodiment, if it is determined that the AP did not schedule the allocation of the second DiL RU during the TXOP, the first frame is configured to be transmitted on a portion of the first DiL RU.

[0052] Specifically, the method further includes receiving a second frame transmitted by the second STA on a second portion of the first DiL RU allocated by the AP to the first STA.

[0053] According to an embodiment, if it is determined that the AP schedules the allocation of the second DiL RU during the TXOP, the first frame is configured to be transmitted on all of the first DiL RUs.

[0054] Specifically, the method further includes:

[0055] During the TXOP, the second DiL RU is received from the AP to allocate to the first STA;

[0056] Transmit the third frame to the second STA on the first part of the second DiL RU; and

[0057] The second frame transmitted by the second STA is received on the second part of the second DiL RU allocated by the AP to the first STA.

[0058] In one implementation, the determination includes: obtaining information from the AP indicating whether the AP schedules the allocation of the second RU to the first STA for DiL communication during the TXOP.

[0059] According to an embodiment, the allocation of the first DiL RU and the allocation of the second DiL RU are included in different frames received by the AP in the TXOP in a cascaded sequence.

[0060] Specifically, the frame including the allocation of the first DiL RU also includes information instructing the AP to schedule the allocation of the second DiL RU to the first STA in a subsequent frame during the TXOP.

[0061] According to an embodiment, the allocation of the first DiL RU and the allocation of the second DiL RU are included in a single frame received from the AP.

[0062] In one implementation, the information instructing the AP to schedule the allocation of the second DiL RU to the first STA during the TXOP is obtained from the allocation of the second DiL RU in the received frame.

[0063] According to an embodiment, a frame that includes the allocation of one or more DiL RUs is a trigger frame or a data or control frame that includes a Trigger Resource Scheduling (TRS) field.

[0064] Some other aspects of the present invention provide a method for wireless communication, the method comprising performing the following steps at a first station (STA):

[0065] During the transmission opportunity (TXOP) set by the AP, the first resource unit (RU) is allocated from the access point (AP) to the first STA for direct link (DiL) communication;

[0066] During the TXOP, the second RU is received from the AP and allocated to the first STA for DiL communication;

[0067] The first frame is transmitted from the first DiL RU to the peer second STA;

[0068] Transmit the third frame to the second STA on the first part of the second DiL RU; and

[0069] The second frame transmitted by the second STA is received on the second part of the second DiL RU allocated by the AP to the first STA.

[0070] In one implementation, the second frame is a response frame to the first frame.

[0071] The following describes additional optional features relating to different aspects of the invention in connection with a station. Although one method is referred to, it can be converted into an apparatus or program according to the invention.

[0072] In one implementation, the AP uses an orthogonal frequency division multiple access (OFDMA) scheme to allocate one or more multi-user (MU) resource units in the operating band of the basic service set (BSS).

[0073] In one implementation, the allocated DiL RU has a bandwidth that is a multiple of the 20MHz channel.

[0074] In one implementation, the allocated DiL RU has a bandwidth spanning the entire operating frequency band.

[0075] This avoids co-channel interference caused by desynchronization.

[0076] In one implementation, peer communication in the allocated DiL RU is performed using a single-user (SU) format.

[0077] This allows the transmitting station to set values ​​for transmission parameters suitable for point-to-point communication. For at least some of the parameters, the values ​​selected by the transmitting station can differ from those set or specified by the AP for uplink communication. The source STA can, for example, select different transmission power when transmitting to a peer destination STA compared to when transmitting to the AP.

[0078] In one implementation, transmitting the first frame includes:

[0079] The first STA selects the value of at least one transmission parameter; and

[0080] Using the value selected by the STA, the first frame is sent to the second STA on the DiL RU assigned by the AP.

[0081] In one implementation, the transmission parameters are one of the following: the encoding type of the first frame, MCS, DCM, and spatial stream (SS).

[0082] In one implementation, the first frame transmitted from the first STA to the peer second STA includes a physical (PHY) preamble and a payload, wherein the payload is transmitted on the DiL RU and the PHY preamble is transmitted on each of the 20MHz channels forming the DiL RU.

[0083] In some embodiments, the second STA is not associated with the AP.

[0084] Certain other aspects of the present invention provide a method for wireless communication, comprising performing the following steps at an access point (AP):

[0085] The transmission includes the allocation of Direct Link (DiL) Resource Units (RUs) to Stations (STAs) for DiL communication; and

[0086] Configure the network allocation vector (NAV) of the AP to align with the end of the DiL RU.

[0087] Unlike regular downlink and uplink communication involving the AP as either a sender or receiver, the AP does not transmit or receive during its allocated DiL RU period. Therefore, the AP sets its NAV for the entire duration of the DiL RU to prevent premature access to the channel (which could interfere with ongoing P2P communication). For example, interference can occur if the destination peer STA is too far from the AP, such as when the destination STA is not associated with the AP. In this case, the signal transmitted by the destination STA during the DiL RU period can reach the AP with a strength below the detection threshold, and therefore the AP will sense that the medium is idle during that period (because its NAV is not set).

[0088] In one implementation, the configuration is based on the time TXTIME0 required to transmit Physical Protocol Data Units (PPDUs) on the allocated DiL RU.

[0089] In one implementation, the frame also includes a length field indicating the length of the allocated DiL RU, thereby allowing the STA to determine the time TXTIME0.

[0090] According to an embodiment, the frame that includes the allocation of the DiL RU is a trigger frame or a data or control frame that includes a Trigger Resource Scheduling (TRS) field.

[0091] Certain other aspects of the present invention provide a method for wireless communication, comprising performing the following steps at an access point (AP):

[0092] During a transmission opportunity (TXOP) set by the AP, the transmission includes the allocation of a first resource unit (RU) to a first station (STA) for the first frame of direct link (DiL) communication;

[0093] During the TXOP, information instructing the AP to schedule the allocation of the second RU to the first STA in a subsequent frame for DiL communication is transmitted to the first STA; and

[0094] During the TXOP, a second frame is transmitted, comprising the allocation of the second RU to the first STA for the DiL communication.

[0095] According to an embodiment, the first frame and the second frame are transmitted by the AP in a cascaded sequence within the TXOP.

[0096] According to an embodiment, the first frame and the second frame are each a trigger frame or a data or control frame that includes a Trigger Resource Scheduling (TRS) field.

[0097] Additional optional features relating to different aspects of the invention in relation to AP are described below. Although one method is referred to, it can be converted into an apparatus or procedure according to the invention.

[0098] In an embodiment, the AP allocates one or more multi-user (MU) resource units using an orthogonal frequency division multiple access (OFDMA) scheme in the operating frequency band of the basic service set (BSS).

[0099] In a preferred implementation, the allocated DiL RU has a bandwidth that is a multiple of the 20MHz channel.

[0100] In another preferred implementation, the allocated DiL RU has a bandwidth spanning the entire operating frequency band. This avoids co-channel interference caused by desynchronization.

[0101] Specifically, point-to-point communication within the allocated DiL RU is performed using a single-user (SU) format. This allows the transmitting station to set values ​​for transmission parameters suitable for point-to-point communication. For at least a portion of the parameters, the values ​​selected by the transmitting station can differ from the values ​​set or specified by the AP for uplink communication. The source STA can, for example, select different transmission power when transmitting to the peer destination STA compared to when transmitting to the AP.

[0102] The present invention also provides a wireless communication device for a first station (STA), comprising:

[0103] A receiver configured to receive allocations of resource units (RUs) to the first STA from an access point (AP) for direct link (DiL) communication; and

[0104] A transmitter configured to transmit a first frame to a peer second STA on the first portion of an allocated DiL RU, and wherein...

[0105] The receiver is also configured to receive a second frame transmitted by the second STA on a second portion of the DiL RU allocated by the AP to the first STA.

[0106] The present invention also provides a wireless communication device for a first station (STA), comprising:

[0107] A receiver configured to receive, during a transmission opportunity (TXOP) set by an access point (AP), the allocation of a first resource unit (RU) to the first STA for use in direct link (DiL) communication;

[0108] The processor is configured as follows:

[0109] Determine whether the AP schedules the allocation of the second RU to the first STA for DiL communication during the TXOP, and

[0110] Based on the determination, configure the first frame to be transmitted to the peer second STA on a portion or all of the first DiL RU, and

[0111] The device further includes a transmitter coupled to the processor, the transmitter being configured to transmit a configured first frame to the second STA on the first DiL RU.

[0112] The present invention also provides a wireless communication device for an access point (AP), comprising:

[0113] A transmitter configured to transmit frames comprising the allocation of Direct Link (DiL) Resource Elements (RUs) to Stations (STAs) for DiL communication; and

[0114] A processor configured to configure the network allocation vector (NAV) of the AP to align with the end of the DiL RU.

[0115] The invention also provides a wireless communication device for an access point (AP), including a transmitter configured to:

[0116] During a transmission opportunity (TXOP) set by the AP, a first frame is transmitted, the first frame including the allocation of a first resource unit (RU) to a first station (STA) for direct link (DiL) communication;

[0117] During the TXOP, information is transmitted to the first STA instructing the AP to schedule the allocation of a second RU to the first STA in a subsequent frame for DiL communication; and

[0118] During the TXOP, a second frame is transmitted, which includes the allocation of the second RU to the first STA for DiL communication.

[0119] Another aspect of the invention relates to a non-transitory computer-readable medium that stores a program, which, when executed by a microprocessor or computer system in the device, causes the device to perform any of the methods defined above.

[0120] At least a portion of the method according to the invention can be implemented by a computer. Therefore, the invention can take the form of a completely hardware embodiment, a completely software embodiment (including firmware, resident software, microcode, etc.), or an embodiment combining software and hardware aspects, the hardware of which can generally be referred to herein as a “circuit,” “module,” or “system.” Furthermore, the invention can take the form of a computer program product embodied in any tangible medium having computer-usable program code embodied therein.

[0121] Since this invention can be implemented in software, it can be embodied as computer-readable code for provision to a programmable device on any suitable carrier medium. Tangible carrier media may include storage media such as hard disk drives, magnetic tape devices, or solid-state storage devices. Transient carrier media may include signals such as electrical signals, electronic signals, optical signals, acoustic signals, magnetic signals, or electromagnetic signals (e.g., microwave or RF signals). Attached Figure Description

[0122] Embodiments of the invention will now be described by way of example only and with reference to the following figures, in which:

[0123] Figure 1 Typical wireless communication systems in which embodiments of the present invention can be implemented are illustrated;

[0124] Figure 2a and 2b An example of a conventional trigger-based (TB) MU UL OFDMA transmission with acknowledgment according to 802.11ax is shown;

[0125] Figure 2c and 2d An example of a conventional MU DL OFDMA transmission with confirmation according to 802.11ax is shown;

[0126] Figure 3a The format of the trigger frame for MU UL OFDMA transmission, as described in the 802.11ax standard, is illustrated.

[0127] Figure 3b The format of the trigger-related user information subfield for performing MU UL OFDMA transfers, as described in the 802.11ax standard, is illustrated.

[0128] Figure 3c The format of the TRS subfield for MU UL OFDMA transfers, as described in the 802.11ax standard, is illustrated.

[0129] Figure 3d The format of the common information fields used for MU UL OFDMA transmissions, as described in the 802.11ax standard, is illustrated.

[0130] Figure 3e The format of HE SU PPDU is shown;

[0131] Figure 4a From the perspective of the station, a trigger-based (TB) P2P transmission during a transmission opportunity (TXOP) according to an embodiment of the present invention is illustrated;

[0132] Figure 4b An example from the perspective of operating frequency band. Figure 4a TB P2P transmission;

[0133] Figure 5a From the perspective of the station, a trigger-based (TB) P2P and UL transmission during the same transmission opportunity (TXOP) according to an embodiment of the present invention is illustrated;

[0134] Figure 5b An example from the perspective of operating frequency band. Figure 5aTB P2P and UL transmission;

[0135] Figure 6a , 6b 6c illustrates a cascade sequence according to an exemplary embodiment of the present invention;

[0136] Figure 7 A flowchart illustrates an example of a wireless communication method performed by an AP according to an embodiment of the present invention.

[0137] Figure 8 A flowchart illustrates an example of a wireless communication method performed by a first station according to an embodiment of the present invention.

[0138] Figure 9 and Figure 10 The operation of the AP and source STA according to embodiments of the present invention is illustrated using flowcharts. In these embodiments, the AP assigns two DiL RUs to the source STA in the TXOP;

[0139] Figure 11 The operation of the AP according to an embodiment of the present invention is illustrated using a flowchart.

[0140] Figure 12 The operation of the source STA according to an embodiment of the present invention is illustrated using a flowchart;

[0141] Figure 13a A schematic diagram of a communication device according to an embodiment of the present invention is shown; and

[0142] Figure 13b A schematic representation of a wireless communication device according to an embodiment of the present invention is shown. Detailed Implementation

[0143] The techniques described in this paper can be used in various broadband wireless communication systems, including communication systems based on orthogonal multiplexing schemes. Examples of such communication systems include Space Division Multiple Access (SDMA) systems, Time Division Multiple Access (TDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, and Single Carrier Frequency Division Multiple Access (SC-FDMA) systems. SDMA systems can utilize sufficiently different directions to simultaneously transmit data belonging to multiple user terminals. TDMA systems allow multiple user terminals to share the same frequency channel by dividing the transmitted signal into different time slots or resource units, where each time slot is assigned to a different user terminal. OFDMA systems utilize Orthogonal Frequency Division Multiplexing (OFDM), a modulation technique that partitions the entire system bandwidth into multiple orthogonal subcarriers or resource units. These subcarriers may also be referred to as frequency modulation, inter-cells, etc. Using OFDM, each subcarrier can be modulated independently with data. SC-FDMA systems can utilize interleaved FDMA (IFDMA) for transmission on subcarriers with cross-system bandwidth distribution, centralized FDMA (IFDMA) for transmission on blocks of adjacent subcarriers, or enhanced FDMA (IFDMA) for transmission on multiple blocks of adjacent subcarriers.

[0144] The teachings of this paper can be incorporated into various devices (e.g., stations) (e.g., implemented within the device or by the device). In some aspects, a wireless station implemented according to the teachings of this paper may include an access point (so-called AP) or may not include an access point (so-called non-AP station or STA).

[0145] An AP may include, be implemented as, or be referred to as a B-node, radio network controller (“RNC”), evolved B-node (eNB), 5G next-generation base station (gNB), base station controller (“BSC”), base transceiver station (“BTS”), base station (“BS”), transceiver function (“TF”), radio router, radio transceiver, basic service set (“BSS”), extended service set (“ESS”), radio base station (“RBS”), or any other term.

[0146] A non-AP station may include, be implemented as, or be referred to as a subscriber station, subscriber unit, mobile station (MS), remote station, remote terminal, user terminal (UT), user agent, user device, user equipment (UE), user station, or any other term. In some implementations, an STA may include a cellular phone, cordless phone, Session Initiation Protocol (“SIP”) phone, Wireless Local Loop (“WLL”) station, personal digital assistant (“PDA”), handheld device with wireless connectivity, or some other suitable processing device connected to a wireless modem. Accordingly, one or more aspects of the teachings herein may be incorporated into a telephone (e.g., a cellular phone or smartphone), a computer (e.g., a laptop computer), a tablet, a portable communication device, a portable computing device (e.g., a personal data assistant), an entertainment device (e.g., a music or video device, or a satellite radio), a Global Positioning System (GPS) device, or any other suitable device configured to communicate via wireless or wired media. In some aspects, a non-AP station may be a wireless node. Such wireless nodes can provide connectivity to or from networks (e.g., wide area networks such as the Internet or cellular networks) via wired or wireless communication links, for example.

[0147] Figure 1 An example of a wireless communication system is illustrated, in which several communication stations 101-107, 110 exchange data frames via a radio transmission channel 100 of a wireless local area network (WLAN). A central station, i.e., an access point (AP) 110, can manage the basic service set (BSS) of the wireless system. If the AP implements a virtual AP, the AP can manage more than one BSS. The radio transmission channel 100 is defined by an operating frequency band (OFB) consisting of a single channel or multiple channels forming a composite channel.

[0148] An exemplary scenario of direct communication corresponding to today's growth trend is point-to-point (P2P) transmission between non-AP stations (e.g., STA102 and STA 101 shown in the diagram). Technologies supporting P2P transmission include, for example, WiFi-Miracast (RTM) or wireless display scenarios, or Tunneled Direct Link Setup (TDLS). Note that even though P2P streams are typically not numerous, the data volume of each stream can be substantial (typically low-compressed video, ranging from 1080p60 to 8K UHD resolution).

[0149] Each STA 101-107 can associate with AP 110 during the association process. During the association process, AP 110 assigns a specific association identifier (AID) to the requesting STA. For example, the AID is a 16-bit value that uniquely identifies the STA.

[0150] Stations 101-107 and 110 can compete with each other using EDCA (Enhanced Distributed Channel Access) contention to access the radio medium for a permitted transmission opportunity (TXOP) and then transmit (single-user, SU) data frames. Stations can also use a multi-user (MU) scheme, where a single station (typically AP 110) is allowed to schedule MU transmissions, i.e., multiple simultaneous transmissions to or from other stations in the wireless network are permitted. One implementation of this MU scheme has been adopted, for example, in the IEEE 802.11ax revision as a multi-user uplink and downlink OFDMA (MU UL and DL OFDMA) procedure.

[0151] refer to Figure 2a In order to actually carry out this MU UL transmission, the 802.11ax standard uses Orthogonal Frequency Division Multiple Access (OFDMA) technology to divide the permitted communication channel into resource units 201-204 (RU) shared by multiple stations in the frequency domain.

[0152] To finely control MU UL transmissions performed by non-AP stations 101-107, AP 110 sends trigger frame 210, which defines how the channel is split into RUs and which non-AP stations are allowed to transmit on each RU. In this example, trigger frame 210 assigns RU 201 to STA1, RU 202 to STA2, RU 2013 to STA3, and RU 204 to STA4. The assignment is made using the AIDs of the non-AP stations.

[0153] Upon receiving trigger frame 210, each non-AP station determines its assigned RU based on its own AID and can begin transmitting MU frame 220 (referred to as HETB PPDU) to the AP on its assigned RU after the SIFS period following trigger frame 210.

[0154] Due to the triggering mechanism, the term "trigger-based MU UL transmission" is used.

[0155] After transmitting four HE TB PPDUs in parallel from station STA2 to STA4, AP 110 transmits individual block ACK(BA)230 on each RU or multi-station (M-STA) block ACK(BA)230 over the entire frequency band.

[0156] Figure 2b The same MU UL transmission is illustrated from the perspective of the station.

[0157] Figure 3a The format of a trigger frame for MU UL OFDMA transmission, as described in the 802.11ax standard, is illustrated.

[0158] Trigger frame 210 contains several fields as defined in IEEE standard 802.11ax, and in particular, includes a single public information field 300. Figure 3d ) and multiple user information fields 310.

[0159] Each user information field 310 defines the assignment of the RU to the corresponding non-AP station 101-107 as defined in the public information field 300, as well as the communication parameters regarding UL communication with the AP. For this purpose, the RU allocation subfield 312 identifies the associated RU (center frequency and frequency bandwidth), while the AID12 subfield 311 carries the 12 LSBs of the AID of the non-AP station to which the RU is assigned.

[0160] Bits B39 and 313 of user information field 310 are currently unused. Trigger-related user information subfield 314 is primarily used to provide details related to communication parameters defined in other subfields of user information field 310. Figure 3b The content depends on the type of trigger frame. The format shown in the figure corresponds to the trigger-related user information subfield 314 of the basic trigger frame.

[0161] Therefore, the user information field defined in 802.11ax clearly only authorizes UL transmissions, because only the source non-AP station is identified in AID12 subfield 311.

[0162] Figure 2c An example of MU DL transmission in the frequency domain is shown, where AP 110 transmits data frames (HE PPDU). For MU UL transmission, the 802.11ax standard uses Orthogonal Frequency Division Multiple Access (OFDMA) technology to divide the permitted communication channel into resource elements 201-204 (RU) shared by multiple stations in the frequency domain.

[0163] In the example diagram, AP 110 defines four RUs to communicate with four non-AP stations. Preamble 250 contains a description of the RUs and an ordered list of stations, which will be the destination non-AP stations for DL ​​transmissions on RUs 201-204 respectively.

[0164] Next, AP 110 transmits its data to the station in a data frame (HE PPDU): via RU1201 to STA1, via RU2202 to STA2, via RU3203 to STA3, and via RU4204 to STA4.

[0165] In addition to the data itself, AP 110 can also include the TRS control subfield in the A control field of each HE PPDU sent to non-AP stations. Figure 3cThe TRS subfield shown contains all the indications (without EDCA access media) required for the destination non-AP station (STA1-STA4) to acknowledge the received data in the next MU UL transmission, which is triggered, for example, after SIFS (Short Interframe Space) following MU DL transmission 260.

[0166] like Figure 3c As shown, the TRS 350 subfield according to 802.11ax includes a UL data symbol subfield 351 and an RU allocation 352 for the destination non-AP station to respond to received data. The UL data symbol subfield indicates the number of OFDM symbols in the data field of the HE TB PPDU response and is set to the number of OFDM symbols minus 1. Other parameters of the TRS subfield 350 are used to indicate the modulation (MCS) 315 and transmission power (based on the expected RSSI on the AP side) to be used for efficient reception of acknowledgments by the AP. Bit B25 (321) is currently unused.

[0167] Back Figure 2c AP 110 then uses RU to send its data frame (PPDU) 260 to the non-AP station.

[0168] Non-AP stations can decode PPDU 260 received from AP, including decoding the contents of the TRS subfield 350 of the received PPDU.

[0169] Then, the non-AP station prepares its block ACK(BA) packet 270.

[0170] After the PPDU reception ends and there is a SIFS (Short Interframe Space), each non-AP station transmits the BA packet 270 prepared by that non-AP station on the RU specified in field 352 of the received TRS subfield 350.

[0171] Figure 2d The same MU DL transmission is illustrated from the perspective of the station.

[0172] Figure 3e The format of a HE SU PPDU is illustrated. In addition to the standard preamble (L-STF, L-LTF, L-SIG), it includes RL-SIG (repeated conventional signal field), HE-SIG-A (HE signal A), HE-STF (HE short training field), HE-LTF (HE long training field), data, and PE (packet extension) fields. The conventional preamble and HE-SIG-A are replicated on each 20MHz channel. The HE-SIG-A field includes several subfields indicating the set of transmission parameters of the PPDU, such as bandwidth (BW), modulation and coding scheme (MCS), number of data streams, and coding type.

[0173] According to embodiments of the invention, the format shown for the HE SU PPDU, as well as other possible formats such as HE MU PPDU and HE TB PPDU (not shown), can be used to represent frames. Other formats, of course, are conceivable besides these HE PPDUs. For example, the Very High Throughput (EHT) frames introduced in 802.11be can also be used effectively.

[0174] To further address the challenges of increased bandwidth and reduced latency requirements in wireless communication systems in high-density environments, aspects of this invention seek to efficiently modify the permitted transmissions in triggered MU transmissions. These aspects provide features that allow for the scheduling and efficient management of Direct Link (DiL) (also known as Point-to-Point (P2P)) transmissions in MU transmissions. It can be seen that management is implemented between the AP, which distributes resource units allocated for DiL transmissions, and a first (source) station that uses these resources to transmit data and subleases a portion of the allocated bandwidth to a second (destination) station that uses the subleased bandwidth to transmit response frames.

[0175] The allocation of DiL resource units can be performed by trigger frames or data or control frames that include the Trigger Resource Scheduling (TRS) subfield.

[0176] To this end, the Triggered Resource Scheduling (TRS) subfield of trigger frames and / or data or control frames sent by the AP to non-AP stations is enhanced to allocate resource units of MU transmissions for data transmission toward the destination non-AP station. In addition to downlink (DL) and uplink (UL) capabilities, they also provide direct link (DiL) transmission capabilities within triggered MU transmissions.

[0177] As will be described in more detail herein, the first (source) station, which has been assigned a P2P RU by the AP, can share time with the second (destination) station for P2P RU. Therefore, both the source and destination stations can use, for example, resource units allocated by the trigger frame for point-to-point transmissions to the source station to exchange data P2P.

[0178] The source station uses the P2P capabilities provided during the triggered MU transmission to send data frames. Furthermore, the destination station can then receive data frames through the allocated resource units and respond to the source station with a response frame.

[0179] Below, DiL RU or P2P RU refers to resource units allocated for direct link transmission in this way.

[0180] Figure 4a From the perspective of the station, a trigger-based (TB) P2P transmission during a transmission opportunity (TXOP) according to an embodiment of the present invention is illustrated.

[0181] In this example, the P2P transmission 420 is triggered by frame 410, which may be a trigger frame (210) or a control or data frame containing a TRS subfield. Furthermore, it is assumed that the P2P transmission occupies the entire operating frequency band, which in this example corresponds to a 40MHz composite channel.

[0182] Frame 410 transmits a signal notification of such a DiL resource unit. For example, a single bit can be used to signal the P2PRU. Then, upon receiving frame 410, the source station can determine whether it has been allocated a resource unit for DiL, and if so, which resource unit.

[0183] The source station uses a portion of the allocated P2P RU to transmit Physical Protocol Data Units (P2PPPDUs) 421 to the destination station. The destination station uses another portion of the P2P RU to transmit response frames 422, such as acknowledgment (ACK) frames.

[0184] Figure 4b An example from the perspective of operating frequency band. Figure 4a TB P2P transmission.

[0185] Figure 5a From the perspective of the station, a trigger-based (TB) P2P and UL transmission during the same transmission opportunity (TXOP) according to an embodiment of the present invention is illustrated.

[0186] In these embodiments, the AP uses a trigger frame (TF or HE MU PPDU TRS) to allocate more than one UL / DL / DiL phase. Two phases are illustrated in the figure. The P2P phase allows P2P communication between STA1 and STA2 (transmission of P2P PPDU and reception of ACK), and the uplink phase, during which STA3 and STA4 each transmit TB PPDUs to the AP. The trigger frame specifies each RU in both the time and frequency domains. For the time domain, each RU can be defined from the end of the trigger frame, either by using a global time value or relative to the end of a previously allocated RU. The former allows the station to enter a power-saving mode. The latter allows for better synchronization because it is less sensitive to possible clock shifts used by the station for measurement.

[0187] Figure 5b An example from the perspective of operating frequency band. Figure 5a TB P2P and UL transmission.

[0188] Figure 6a A cascade sequence according to an exemplary embodiment of the present invention is illustrated.

[0189] In the illustrated embodiment, two stations (STA1 and STA2) have already established a direct link session prior to the MU concatenation sequence. Two additional stations (STA3 and STA4) have some data to be transmitted to the AP.

[0190] In this example embodiment, the AP initiates a MU concatenation sequence to share its earned TXOPs between peers for direct link transmissions, and to share its earned TXOPs between two additional STAs for MU UL transmissions.

[0191] To this end, the AP, for example, creates a trigger frame that designates STA1 as the receiver of resource units across the entire operating band. This means that no other transmissions will occur concurrently with STA1's transmission. The AP may also send a MU DL PPDU containing a single A-MSDU addressed to STA1, which includes a TRS control subfield. This is done by listing only a user information field 310 of the RU assigned to STA1 and indicating the use of all operating bands (in the example of trigger frame 210). The AP also mentions on this RU that it is a RU dedicated to direct link transmission.

[0192] This latest information can be indicated, for example, by encoding the information with 1 bit on a RU dedicated to direct link transmission. Several possibilities exist for signaling the fact that the RU is dedicated to direct link transmission. For example, a reserved bit 313 in the user information field can be used to indicate a direct link RU (or bit 321 of the TRS subfield 350).

[0193] Another possibility is to set the AID 12 field 311 to a specific value indicating that the RU is used for a direct link. Since several fields of the user information field 310 are meaningless in the case of direct link transmission, the station's AID can then be encoded in a specific format in a trigger-related information field, or in the user information field itself. Then, for example, 12 bits (bits B20 to B31) of the user information field can be reused to indicate one or more of the following: the source peer's AID, the destination peer's AID, or the AID specific to the direct link session between the two peers.

[0194] Then, the AP transmits a trigger PPDU (HE MU PPDU 410), and because the PPDU allocates an RU for direct link transmission to STA1, the AP can set its Network Allocation Vector (NAV), which will have the effect of delaying AP media access until the direct link transmission (including the acknowledgment portion) ends. The fact that the AP sets its NAV after transmitting the trigger PPDU allows for the avoidance of a potential conflict between the acknowledgment frame 422 transmitted by STA2 and the AP's subsequent transmission of HE MU PPDU 411. The problem here is that the AP may not be able to detect the STA2 transmission. STA2 may be outside the reachability range of the AP's BSS, and too far from the AP while being close enough to communicate with STA1.

[0195] Upon receiving the trigger PPDU 410, STA1 (by reading information associated with the assigned RU) determines that the AP has assigned an RU for direct link transmission. STA1 then determines the time TXTIME0 corresponding to the duration of the RU assigned by the AP for DiL communication. TXTIME0 determination may be based on parameter values ​​received in the trigger PPDU (e.g., the UL length field from trigger frame 210, or the UL data symbol parameter 351 and UL HE MCS 315 from TRS control field 350).

[0196] The determination of TXTIME0 can be based on the length field included in the trigger frame or the data symbol subfield included in the TRS subfield. Similar to UL transmissions, the AP can specify these fields for the assigned P2PRU. By considering that all MU RUs during the same transmission phase have the same length for synchronization purposes, UL length 320 and UL data symbol 351 can be used. Since RUs can be assigned for UL and / or P2P transmissions according to embodiments of the invention, subfields 320, 351, and 315 can be renamed TB length, TB data symbol, and TB HE-MCS, respectively. Alternatively, dedicated fields P2P length, P2P data symbol, and P2P HE-MCS can be used.

[0197] As an example of determining TXTIME0 based on TB length, we can use the following relationship:

[0198]

[0199] Alternatively, the following operations can be performed based on TXTIME0 to obtain the TB length:

[0200]

[0201] TXTIME0 can also be determined based on the TB data symbol subfield (351) of the TRS (350) indicating the number of OFDM symbols in the data portion of the HE TB PPDU, and the TB HE MCS field (315) (the size of the HE TB PPDU preamble is known).

[0202] After allocating an RU for direct link transmission, STA1 determines a new transmission time TXTIME1 by subtracting the determined duration TXTIME0, SIFS duration, and the duration TXTIME2 required for the destination peer STA2 to send a response frame (such as an ACK frame) back to the source peer STA1. STA1 determines the optimal MCS value for transmitting data to STA2 based on, for example, the SNR measured during the most recent past transmission received from STA2. This MCS value and TXTIME2 allow determination of the amount of data that can be sent from STA1 to STA2. STA1 then creates a DiL PPDU 421 and transmits it on the RU allocated by the AP. After receiving the DiL PPDU 421 on the RU, STA2 decodes the PPDU, creates an acknowledgment packet 422, and transmits the acknowledgment packet 422 on the same RU within the SIFS duration following the end of the DiL PPDU 421 reception time.

[0203] When the NAV duration expires, the AP senses the medium, and if the medium was idle during the SIFS duration, the AP is allowed to continue the cascading sequence.

[0204] Then, the AP can continue its operation using the cascaded sequence.

[0205] The MU cascading mechanism allows several transmission phases (e.g., UL and DL) to be cascaded within a single TXOP won by the AP. This mechanism provides low-latency transmission for interactive applications, allows the AP greater flexibility in scheduling stations, and is also used within the TWT (Target Wake-up Time) range to time-schedule different stations in power-saving modes (typically dormant) that have negotiated power-saving contracts with the AP. In all these cases, the AP initiates the cascading sequence by sending a Trigger MU PPDU 411 containing at least a trigger frame or an MSDU with a Trigger Response Scheduling (TRS) control subfield.

[0206] In the illustrated example, UL RUs are assigned to stations STA3 and STA4 for transmission of HE TB PPDUs 431 and 432. The assigned RUs can be signaled in different ways in HE MU PPDU 411.

[0207] Upon receiving the trigger HE MU PPDU 411, if stations STA3 and STA4 are identified as the destination of the MU DL transmission (the station's unique identifier AID listed in the HE SIG-B portion of the physical preamble, or the AID identifying the broadcast resource element in the preamble), the stations decode the received MSDU and the included TRS subfield. If the received HE MU PPDU contains a trigger frame, stations STA3 and STA4 are identified as the intended receivers of the user information field 310 in the trigger frame 411 (i.e., the AID12 subfield 311 is equal to 12 LSBs of the station's AID). Each station STA3 and STA4 then decodes the associated user information field.

[0208] Based on the TRS control subfield or trigger frame and user information field, each station determines the assigned resource unit and the associated transmission parameter values ​​(fields, such as MCS, target RSSI, etc.).

[0209] Then, each station generates the packets to be transmitted on its assigned RU. To do this, the station first determines the transmission time (TXTIME0) permitted by the AP. This determination can be made using TB or UL length, data symbols, or the HE MCS field, similar to what has been discussed above. Next, based on the MCS and TXTIME0 indicated by the AP, the station determines the amount of data that can be transmitted and generates an MSDU packet (e.g., containing payload data). The MSDU packet is then encapsulated in HE MU PPDU 431 and 432 and transmitted for a short inter-frame interval (SIFS) duration following the end of reception that triggers HE MU PPDU 411.

[0210] After triggering the transmission of PPDU 411, the AP listens to the medium, waiting for the reception of HE TB PPDU 431 / 432. During the transmission period of HETB PPDU 431 / 432, the AP decodes the PPDUs (all of which are intended for use by the AP). During the SIFS duration following the end of the transmission, the AP is allowed to acquire the medium again and use the medium to continue the concatenation sequence for DL, UL, or DiL transmissions until the TXOP ends. At the end of the TXOP, the AP then sends a multi-STA block ACK packet 440 to acknowledge all HE MU PPDUs received by the AP during the concatenation sequence.

[0211] It is worth noting that the AP can initiate a concatenation sequence by sending a trigger PPDU 411 that is not assigned to a RU for a direct link, and continue the sequence by transmitting a trigger PPDU 410. Any order and / or number of consecutive transmissions of frames 411 and 412 are conceivable.

[0212] Figure 6bA cascade sequence according to another exemplary embodiment of the present invention is illustrated.

[0213] In this embodiment, the MU concatenation sequence is organized to allow for rapid transmission of acknowledgments for direct link communication, while simultaneously supporting multi-user OFDMA transmission in parallel with the direct link transmission. At the start of the concatenation sequence, the AP schedules the transmission of direct link services in both directions, but transmits acknowledgments in subsequent time slots of the sequence. When the AP sends a trigger PPDU 410b, it indicates at least one RU for the direct link transmission. Figure 6b In the example, the AP schedules STA1 in parallel for direct link transmission and STA3 and STA4 for UL transmission. Typically, the AP does not schedule transmissions for stations that are receivers of direct link communications scheduled in the same trigger PPDU (unless the station explicitly mentions its ability to simultaneously receive and transmit data on two different RUs).

[0214] The signal notification indicating that the RU is dedicated to direct link transmission can be used with Figure 6a The signal notification is the same in the embodiments, but the RU allocated for direct link transmission does not necessarily occupy the entire operating band. In this example, the only preference is that the DiL RU occupies a bandwidth that is a multiple of 20 MHz. This allows the DiL station to use a SU PPDU with its own preamble, which is different from the MU UL preamble transmitted in parallel on the remaining 20 MHz channel of the operating band. When transmitting the trigger PPDU 410b, the AP can set its NAV to the duration of the direct link transmission because if STA3 and / or STA4 cannot transmit its HE TB PPDU for any reason, the AP will not acquire the medium before the end of the direct link transmission.

[0215] Upon receiving trigger PPDU 410b, stations STA1, STA3, and STA4 determine that they intend to use the RU allocated by the AP. In this embodiment, all stations calculate their TXTIME0 in the same manner as described above, which should yield the same value. All transmissions (P2P PPDU 423 and HE TB PPDUs 424 and 425) end approximately at the same time.

[0216] and Figure 6a The main difference between this embodiment and the one shown is that the DiL transmitter STA1 does not need to immediately acknowledge STA2 (e.g., by requesting a delayed block ACK), and no time is allocated for the transmission in the current phase. Therefore, STA2 will wait for its next transmission opportunity (one of the next phases of the cascade sequence or a future TXOP) to send back an acknowledgment.

[0217] At the end of the transmission, the AP acquires the medium for the SIFS duration following the end of the last transmission and sends a new trigger PPDU 411b to trigger another peer (STA2) in a direct link session, for example. According to an embodiment of the invention, this second trigger PPDU 411b can also trigger a MU UL parallel transmission from another station (e.g., STA3). Upon receiving this second trigger PPDU 411b, STA2 uses the same mechanism as previously described to determine TXTIME0 and prepares a PPDU containing an acknowledgment of DiL PPDU 423 received during a previous stage of the concatenated sequence. Alternatively or additionally, if there is still space according to the calculated TXTIME0, the PPDU may also include data to be sent to peer STA1. STA3, also having an RU assigned by the AP, prepares a HE TB PPDU in a similar manner as during a stage of the sequence.

[0218] One advantage of this embodiment is that it allows for more flexible scheduling of a large number of stations during TXOP due to the possibility of simultaneous transmission (using the MU UL OFDMA scheme). In the embodiment where the AP directly schedules the P2P RU to the responding station (STA2) in the second trigger PPDU 411b, the AP needs to know the two peers involved in the P2P communication. In a variant, the AP schedules the P2PRU to the source STA1 in the second trigger PPDU 411b. STA1 then transmits a frame on the second assigned P2P RU to trigger a response frame from the destination station STA2, and thus shares the P2P RU in time. STA1 acts as the triggering station on behalf of the AP. The AP then must indeed know the destination peer STA2 (STA2 may even be unrelated to the AP).

[0219] Because acknowledgments for direct link packets sent during one phase of a concatenated sequence are sent during one of the subsequent phases of the same sequence, data sent during the final phase of the sequence cannot be acknowledged before the end of the TXOP.

[0220] To solve this problem, a combination of methods was conceived. Figure 6a and Figure 6b Another embodiment of the present invention, which is described in the two embodiments described herein. The first part of the cascade sequence is as follows: Figure 6b The embodiments operate as described above, and include the final stage of a concatenated sequence of direct link transmissions, such as... Figure 6a The operation is as described in the first phase (sending an acknowledgment immediately after receiving the DiL PPDU from the peer station).

[0221] In this other embodiment, a new signaling notification can be used to indicate in the definition of the resource unit assigned to a station for a direct link that no subsequent direct link RU will be scheduled in the current cascading sequence for the station. This signaling notification, "No more DiL RUs," can be in the TRS control subfield or trigger the relevant user information field 314, for example, using one of the reserved bits currently present in the 802.11ax format of user information field 310. Alternatively, similar to the bits indicating RUs for direct links, a dedicated signaling notification can be placed in the range of bits 20 to 31 of user information field 310, since these bits are unavailable in the case of direct link communication.

[0222] Figure 6c A cascade sequence according to another exemplary embodiment of the present invention is illustrated.

[0223] The main advantage of this embodiment is that one of the two peers having a direct link session established between them can be outside the scope of the BSS. In this embodiment, the AP only schedules transmissions for peers registered to its BSS, and that peer can, for example, sublease a portion of its allocated time to another peer using a reverse protocol (RDP). In this embodiment, when STA1 receives a trigger frame 410c for allocating a direct link RU, the station can, as follows: Figure 6a Alternatively, the direct link RU can be used for its own needs as in the previous embodiment of 6b, or a portion of the direct link RU can be subleased to another peer of the direct link session.

[0224] exist Figure 6cIn the example, when station STA1 receives the trigger PPDU 410c for allocating DiL RUs, STA1 determines the allocated transmission time (TXTIME0) as discussed in other embodiments, and then prepares a P2P PPDU and transmits it to peer station STA2 during all times of TXTIME0 (i.e., occupying all P2P RUs). In a subsequent stage of the same concatenation sequence, when STA1 receives the trigger PPDU 411c, and after determining the allocated transmission time (TXTIME0), STA1 acts as the reverse initiator and transmits PPDU 440 (with a transmission duration TXTIME1 that is shorter than the determined duration TXTIME0). PPDU 440 includes an HT control field and a duration / ID field, the HT control field indicating a reverse permission (RDG) bit set to 1 to indicate that the receiving peer can transmit data to STA1 in the reverse direction, and the duration / ID field preferably set to the maximum remaining time (TXTIME0-TXTIME1-SIFS) until the end of the allocated time in the current concatenation stage. STA2 can then use the SIFS medium after receiving the RDP PPDU 440. As the RD responder, STA2 must ensure that its PPDU 441 transmission time will not exceed the remaining duration indicated in the duration / ID field of PPDU 440, and then send a DiL PPDU 441 to STA1, which contains an acknowledgment of the PPDU previously received from STA1, or data for STA1, or a combination of both.

[0225] The main difference from the regular use of the reverse protocol is that STA2 is unaware that the current reverse session is occurring within the concatenation sequence. Therefore, STA1 is responsible for handling the special conditions imposed by this scheme. For example, STA1 should ensure that the current transmission does not end before the allocated time expires. Because premature termination of STA2's transmission could allow another station to acquire the medium, thus disrupting the concatenation sequence or interfering with simultaneous HE TB transmissions, STA2 may need to transmit padding data until the allocated time expires. If STA2 fails to add the necessary padding, STA1 can add padding on STA2's behalf. For example, upon receiving PPDU 441 sent by STA2, STA1 checks whether STA2 will transmit additional data (by examining more data bits of the HT control field included in the QoS data of the PPDU sent by STA2). If STA2 is no longer transmitting data and the end of the allocated RU has not yet been reached, STA1 must send padding data to occupy the medium until the transmission time of the allocated RU expires.

[0226] In a variant, the AP can indicate in the user information field sent to STA1 for allocating a DiL RU that an additional DiL RU will be allocated for the direct link session in at least one subsequent stage of the current cascading sequence. This can be achieved by using, for example... Figure 6b The signal notification that "DiL RU is no longer available" is used.

[0227] In another variation, the possibility of using the reverse protocol in a DiL RU allocated by the AP is controlled by a signal notification indicating whether RDP use is permitted (e.g., bits in the trigger frame's user information field or TRS control field). This allows the AP to schedule parallel MU UL transmissions performed by the station using HETB PPDUs without any risk of interference.

[0228] For ease of description, all examples of cascaded embodiments ( Figures 6a to 6c The example illustrates a cascaded sequence comprising two stages. Of course, a cascaded sequence according to embodiments of the invention may include only one stage or more than two stages.

[0229] Figure 7 Flowcharts illustrate examples of wireless communication methods performed by an AP according to embodiments of the present invention. These embodiments can be implemented within a cascade sequence or independently of any cascade sequence.

[0230] At step 701, the AP transmits a frame to the first station (e.g., STA1) allocating a DiL RU. As discussed in previous embodiments, the allocation of the DiL RU may be included in the Triggered Resource Scheduling (TRS) field of a trigger frame or a data or control frame received from the AP.

[0231] In a variant, the AP can signal to the first and / or second station constraints relating to the use of the assigned second DiL RU. For example, the AP can indicate whether to authorize the use of the reverse protocol on the assigned DiL RU.

[0232] At step 702, the AP optionally configures its Network Allocation Vector (NAV) to align with the end of the DiL RU. The AP sets its NAV for the entire duration of the DiL RU to prevent premature access to the channel (which could interfere with ongoing P2P communication). Alternatively, the AP can set a timer with the duration of the DiL RU plus a SIFS at the end of the transmission of the frame that allocates the DiL RU to the first station. The timer then expires corresponding to the end of the DiL RU, and the AP can then sense the medium again to transmit data.

[0233] Figure 8An example of a wireless communication method performed by a first station according to an embodiment of the present invention is illustrated using a flowchart. The first station is considered to have a direct link session established with a second station. These embodiments can be implemented within a cascade sequence or independently of any cascade sequence.

[0234] At step 801, the first station receives the allocation of the DiL RU from the AP. Optionally, the first station determines whether the reverse direction is allowed in the DiL RU.

[0235] At step 802, the first station transmits the first frame to the peer second station on the first portion of the allocated DiL RU. The first station uses only a portion of the DiL RU to share the remaining portion of the allocated DiL RU with the second STA.

[0236] At step 803, the first station receives a second frame from the second station on the second portion of the DiL RU allocated to the first STA. The second frame may be a response frame or an ACK frame to the first frame transmitted by the first station.

[0237] Figure 9 and Figure 10 The operation of the AP and source STA according to embodiments of the present invention is illustrated using flowcharts. In these embodiments, the AP assigns two DiL RUs to the source STA in the TXOP. These embodiments can be implemented within a cascade sequence or independently of any cascade sequence.

[0238] At step 901, the AP assigns the first DiL RU and the second DiL RU to the first station. As discussed in the previous embodiments, the allocation of DiL RUs may be included in the Triggered Resource Scheduling (TRS) field of a trigger frame or a data or control frame received from the AP.

[0239] In one embodiment, the allocation of the two DiL RUs is signaled to the first STA in one frame (e.g., a trigger frame). In other embodiments, the allocation of the two DiL RUs is signaled to the first STA in two different frames (e.g., trigger frames).

[0240] In the case of a trigger frame (TF or HE MU PPDU TRS), the frame must specify each DiL RU in both the time and frequency domains so that the station to which the DiL RU is assigned can locate it. For the time domain, a DiL RU can be defined from the end of the trigger frame, either by using a global time value or relative to the end of a previously assigned RU. The former allows the station to enter a power-saving mode. The latter allows for better synchronization because it is less sensitive to possible time shifts due to the accuracy of the clock used by the station for time measurement.

[0241] At step 902, the AP optionally configures its Network Allocation Vector (NAV) to align with the end of the second DiL RU. The AP sets its NAV to prevent the AP from prematurely accessing the channel (which could potentially interfere with ongoing P2P communication).

[0242] Note that in the illustrated embodiment of the AP, the NAV is configured to be aligned with the end of the second DiL RU because it is assumed that the first DiL RU and the second DiL RU are consecutive, i.e., separated only by SIFS. For example, if the two DiL RUs are not consecutive and there are DL and / or UL RUs between them, the AP can configure two NAVs, each associated with one DiL RU.

[0243] Alternatively, the AP can use a timer to measure the total time period during which P2P transmissions are in progress and AP access should be blocked.

[0244] More generally, the AP will assign more than one DiL RU to a pair of peers that have established direct link sessions.

[0245] refer to Figure 10 At step 1001, the first station receives the allocation of the first DiL RU and the second DiL RU from the AP in the TXOP. At step 1002, the first station uses the entire allocation time to transmit the first frame to its peer, the second station. Then, the first station shares the second DiL RU with the second station. The first station transmits a third frame, for example including a signal notification of RD permission, on the first portion of the allocated DiL RU (step 1003), and then receives a second frame (response frame) from the second station on the second portion of the allocated DiL RU (step 1004).

[0246] Figure 11 The operation of the AP according to an embodiment of the present invention is illustrated using a flowchart.

[0247] The AP transmits a first frame (1101) in the TXOP that allocates the first DiL RU to the first STA, and a second frame (1104) in the TXOP that allocates the second DiL RU to the first STA. To notify the first STA of the upcoming allocation of the second DiL RU, the AP transmits information in the subsequent second frame regarding the AP's scheduling of the allocation of the second DiL RU to the first STA (1102). The first STA uses this information to efficiently manage the resources allocated to it and their sharing with peer STAs, such as, for example, according to... Figure 12 Examples of implementations.

[0248] According to an embodiment, the AP can signal to the first station and / or the second station constraints relating to the use of the allocated second DiL RU. For example, the AP can indicate whether the use of the reverse protocol is authorized in the allocated DiL RU.

[0249] The AP may optionally configure its network allocation vector (NAV) to align with the end of the corresponding allocated DiL RU after each transmission of a frame that allocates a DiL RU (1103 and 1105).

[0250] Figure 12 The operation of the first STA according to an embodiment of the present invention is illustrated using a flowchart.

[0251] At step 1201, the first STA receives the allocation of the first DiL RU from the AP during TXOP.

[0252] At step 1202, the STA determines whether the AP schedules the allocation of the second RU to the first STA for DiL communication during TXOP. This determination is based on information received from the AP.

[0253] According to an embodiment, this information is explicitly sent by the AP (e.g., Figure 11 ).

[0254] According to an embodiment, this information is implicit based on the allocation made by the AP. This is, for example... Figure 9 In this embodiment, the allocation of the first DiL RU to the STA and the allocation of the second DiL RU to the STA are both signaled in the same frame. Therefore, based on this allocation information, the first STA can determine the AP-scheduled allocation of the second DiL RU before starting to transmit frames on the first allocated DiL RU.

[0255] If it is determined at step 1202 that the AP does not schedule the second DiLRU to the first STA (i.e., does not allocate or does not intend to allocate it), then the first STA then executes steps 1203 and 1204 (which are similar to steps 1204 and 1204 respectively). Figure 8 Steps 802 and 803).

[0256] If it is determined at step 1202 that the AP has indeed scheduled (i.e., allocated or intends to allocate) the second DiLRU to the first STA, then the first STA transmits the first frame to the second STA on the first allocated DiLRU at step 1206 (similar to step 1002). After receiving the allocation of the second DiLRU at step 1207, the first STA executes steps 1208 and 1209 (similar to...). Figure 10 Steps 1004 and 1005).

[0257] Some features of the different embodiments described in this invention can be listed below:

[0258] - The process for setting up / removing direct links remains unchanged;

[0259] - The triggered P2P characteristics can be controlled by capability exchange (at either AP or STA level);

[0260] - P2P services are triggered by the AP for "single-user style" PPDU:

[0261] ○ An AP can share a portion of its TXOP with P2P services based on the 802.11ax cascading mechanism. For example, an AP can provide resources to its associated source P2P sites.

[0262] ○ P2P services can use “P2P RU” = n × 20MHz, covering all operating frequency bands during this time period;

[0263] ○ Simple signal notification (usually 1 bit) to notify "P2P RU" with a signal;

[0264] ○ P2P services can use their own preambles on different channels:

[0265] ■ The AP does not need to provide all trigger transmission parameters (e.g., MCS);

[0266] ■ No synchronization requirement (even for the ACK portion);

[0267] ○ It is conceivable that SU or MU PPDU formats could be used for P2P transmission.

[0268] The various embodiments described in this invention advantageously allow for the combined benefits of MU and SU operations. For example, according to MU operation:

[0269] - Improves the efficiency of global cells; more efficient than SU media access solutions (previous EDCA direct link protocol, RDP protocol, etc.), and

[0270] -APs can still share uplink / downlink RUs from other STAs.

[0271] And according to SU operation:

[0272] - P2P stations communicate individually in their assigned RU channels (e.g., operating bands);

[0273] - The AP does not need to know the P2P transmission characteristics (therefore it does not need to provide all triggering parameters, such as MCS);

[0274] - Acknowledgment can be performed without interference issues (no parallel transmission); and

[0275] - The receiving peer station (destination STA) can be located outside the AP's BSS.

[0276] Embodiments of the present invention are shown, for example:

[0277] - Trigger frames are a natural tool for scheduling non-AP stations (including P2P STAs);

[0278] - Reuse cascading mechanisms allow for time sharing in P2P with limited modifications; and

[0279] - The triggered P2P operation is very simple:

[0280] ○ P2P stations can be triggered on the operating frequency band, and

[0281] ○ P2P sites can use their own PPDU format during the shared time period (including ACK).

[0282] Figure 13a A communication device 1300 (not AP stations 101-107 or access point 110) configured to implement at least one embodiment of the present invention is illustrated schematically. The communication device 1300 may preferably be a device such as a microcomputer, workstation, or lightweight portable device. The communication device 1300 includes a communication bus 1313, which is preferably connected to:

[0283] This is represented as the Central Processing Unit 1301 of the CPU, such as a processor;

[0284] Memory 1303 is used to store executable code of a method or steps according to an embodiment of the present invention, and registers adapted to record variables and parameters required to implement the method; and

[0285] At least one communication interface 1302 is connected to a wireless communication network, such as a communication network according to one of the IEEE 802.11 standard families, via a transmit and receive antenna 1304.

[0286] Preferably, the communication bus provides communication and interoperability between various elements included in or connected to the communication device 1300. The representation of the bus is not limiting, and in particular, the central processing unit is operable to transmit instructions directly or by means of another element of the communication device 1300 to any element of the communication device 1300.

[0287] The executable code can be stored in memory, which can be read-only, a hard disk, or a removable digital medium (e.g., a disk). According to an alternative variation, the executable code of the program can be received via interface 1302 through a communication network and stored in the memory of the communication device 1300 before being executed.

[0288] In the embodiments, the apparatus is a programmable device that uses software to implement embodiments of the invention. However, alternatively, embodiments of the invention may be implemented wholly or partially in hardware (e.g., in the form of an application-specific integrated circuit or ASIC).

[0289] Figure 13b This is a block diagram schematically illustrating the architecture of a communication device 1300 (AP110 or one of stations 101-107) suitable for at least partially implementing the present invention. As shown, device 1300 includes a physical (PHY) layer block 1323, a MAC layer block 1322, and an application layer block 1321.

[0290] PHY layer block 1323 (here, the 802.11 standardized PHY layer) has the task of formatting, modulating, or demodulating any 20MHz channel or composite channel, and therefore transmitting or receiving frames such as 802.11 frames, for example, a medium access trigger frame TF 210 for reserving transmission time slots, relative to the radio medium 100 used. Figure 4b ), MAC data and management frames based on a 20MHz width for interaction with traditional 802.11 stations, and OFDMA type MAC data frames with a smaller width than the traditional 20MHz (typically 2 or 5MHz).

[0291] The MAC layer block or controller 1322 preferably includes an 802.11 MAC layer 1324 that implements conventional 802.11ax MAC operations, and an additional block 1325 for at least partially performing the present invention. The MAC layer block 1322 may optionally be implemented in software, which is loaded into RAM 1312 and executed by CPU 1311.

[0292] Preferably, the additional block 1325 (referred to as the triggered MU Tx management module for triggered MU transmission after the medium access trigger frame via OFDMA resource unit (sub-channel)) implements a part of the embodiments of the present invention (from the perspective of the slave station or from the perspective of the AP).

[0293] The 802.11 MAC layer 1324 and the triggered MU Tx management module 1325 interact with each other to accurately handle communications addressed to multiple stations on the OFDMA RU according to embodiments of the present invention.

[0294] At the top of the diagram, application layer block 1321 runs the application that generates and receives data packets (e.g., data packets such as video streams). Application layer block 1321 represents all stack layers above the MAC layer, which is standardized according to ISO.

[0295] Although the present invention has been described above with reference to specific embodiments, the present invention is not limited to these specific embodiments, and modifications within the scope of the present invention will be apparent to those skilled in the art.

[0296] Many further modifications and variations will arise for those skilled in the art when referring to the foregoing illustrative embodiments. These embodiments are given by way of example only and are not intended to limit the scope of the invention, which is defined only by the appended claims. In particular, different features from different embodiments may be interchanged where appropriate.

[0297] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude multiple elements. The mere fact that different features are recited in mutually different dependent claims does not indicate that combinations of these features cannot be used advantageously.

Claims

1. A method for wireless communication over a wireless medium, the method comprising: At the first station, i.e., the first STA, a trigger frame is received from the access point, i.e., the allocation of duration within a transmission opportunity, i.e., TXOP, is provided to the first STA during the allocated duration within the TXOP for point-to-point communication, i.e., P2P communication over the wireless medium. During the first portion of the allocated duration, the first frame is transmitted from the first STA to the peer second STA on the allocated RU for P2P communication. as well as During the second portion of the allocated duration, the first STA receives the second frame transmitted by the second STA on the allocated RU for P2P communication. Where the remaining time of the TXOP after the AP determines that the allocated duration has ended is not 0, the AP is allowed to transmit Physical Protocol Data Units (PPDUs) during the TXOP.

2. The method according to claim 1, wherein, The first part and the second part are time-division multiplexed and separated by short inter-frame intervals, i.e., SIFS.

3. The method according to claim 2, wherein, The transmission of the first frame is configured such that the end of the transmission of the second frame by the second STA is time-aligned with the end of the allocated duration.

4. The method according to claim 3, wherein, The second frame is a response frame to the first frame.

5. The method according to claim 4, wherein, The second frame is an acknowledgment frame, i.e., an ACK frame, sent by the second STA to confirm the receipt of the first frame.

6. The method according to claim 3, wherein, Configuring the transmission of the first frame includes setting the length of the first frame such that the remaining time for the second portion of the allocated duration matches the transmission time of the second frame.

7. The method according to claim 6, wherein, Setting the length of the first frame includes: Based on the time of transmitting the second frame, calculate the time TXTIME1 that can be used by the first STA to transmit the PPDU including the first frame; and The length of the first frame is derived based on the obtained time TXTIME1 and at least one transmission parameter used to transmit the first frame. Wherein, TXTIME1 is calculated as TXTIME0 - TXTIME2 - SIFS, where: TXTIME0 is the allocated duration used for P2P communication, and TXTIME2 is the time required for the second STA to transmit the PPDU including the second frame.

8. The method according to claim 3, wherein, Configuring the transmission of the first frame includes: including a reverse permission, or RD permission, in the first frame to address the second STA, the RD permission allowing the second STA to transmit the second frame to the first STA in the reverse direction.

9. The method according to claim 8, wherein, Configuring the transmission of the first frame further includes including a duration in the first frame that permits the second STA to transmit the second frame.

10. The method according to claim 9, wherein, The duration included in the first frame is set to be equal to the value of TXTIME0-TXTIME1-SIFS, where: TXTIME0 is the allocated duration used for P2P communication, and TXTIME1 is the time required for the first STA to transmit the PPDU including the first frame.

11. The method according to claim 1, wherein, The allocation of RUs used for P2P communication and the length of the allocated duration are included in the trigger frame received from the AP.

12. The method according to claim 1, wherein, The allocation of RUs used for P2P communication and the length of the allocated duration are included in the Trigger Resource Scheduling (TRS) field of the data or control frames received from the AP.

13. The method according to claim 11, wherein, The allocation indicates the center frequency of the RU used for P2P communication and the frequency bandwidth of the PPDU to be transmitted on the RU used for P2P communication.

14. The method according to claim 13, wherein, The time TXTIME0 allocated by the AP for transmitting the PPDU on the RU for P2P communication is obtained based on the length or number of data symbols of the RU used for P2P communication and at least one transmission parameter specified by the AP.

15. The method according to claim 7 or 14, wherein, The transmission parameters are the modulation and coding scheme, i.e., MCS.

16. The method according to claim 1, wherein, The second STA is not associated with the AP.

17. A non-transitory computer-readable medium storing a program that, when executed by a microprocessor or computer system in the device, causes the device to perform the method of claim 1.

18. A computer program product comprising a program that, when executed by a microprocessor or computer system in a device, causes the device to perform the method of claim 1.

19. A system comprising a wireless communication device including a wireless medium, a first station (STA), and an access point (AP), wherein the wireless communication device comprises: A receiver configured to receive from the AP a trigger frame defining the allocation of duration within a transmission opportunity (TXOP), and to provide resource elements (RUs) to the first STA during the allocated duration within the TXOP for point-to-point (P2P) communication over the wireless medium; and A transmitter configured to transmit a first frame to a peer second STA on an allocated RU for P2P communication during a first portion of the allocated duration. The receiver is further configured to receive a second frame transmitted by the second STA on the allocated RU for P2P communication during the second portion of the allocated duration. Wherein, if the remaining time of the TXOP after the AP determines that the allocated duration has ended is not 0, the AP is configured to allow the transmission of Physical Protocol Data Units (PPDUs) during the TXOP.

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