Method and apparatus for optimized multi-ap coordination

Abstract

In 802.11be multi-AP cooperation, a cooperative device that has acquired shared resources advertised by a coordinating AP re-advertises the shared resources to stations outside the coordinating AP's transmission range. Given the short available time, the re-advertisement frame binary repeats most of the coordinating AP's initial advertisement, particularly essentially its entire MAC payload. To facilitate identification of the re-advertisement, the latter includes an empty TA field or excludes the TA field in its header. This also allows any AP to act as a coordinating 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 increased bandwidth and reduced latency requirements of wireless communication systems in high-density environments, multi-user (MU) schemes are being developed to allow a single access point (AP) in a wireless network, used to manage a basic service set (BSS), to schedule MU transmissions—that is, multiple simultaneous transmissions to or from non-AP stations within the BSS. For example, the Institute of Electrical and Electronics Engineers (IEEE) adopted one such MU scheme in draft version 3.0 (D3.0) of the 802.11ax standard in June 2018.

[0004] Due to the characteristics of MU, non-AP stations have the opportunity to gain access to the wireless medium through the following two access schemes: MU scheme and traditional Enhanced Distributed Channel Access (EDCA (Single User)) scheme.

[0005] Each BSS defines a primary channel for the wireless medium (called the primary channel, typically a 20MHz channel or a multiple of 20MHz), on which stations (including APs) compete for EDCA (Electronic Data Acquisition) communication. To increase bandwidth for upcoming transmissions, stations can simultaneously compete for an additional 20MHz channel (called a secondary channel). Therefore, the communication channels licensed for transmission include the primary channel and the optional secondary channel.

[0006] The 802.11ax standard allows an Access Point (AP) to perform MU downlink (DL) transmissions when it wins access to the wireless medium for a Transmission Opportunity (TXOP). During MU DL transmissions on a licensed communication channel, the AP performs multiple simultaneous basic transmissions to various non-AP stations on a so-called Resource Unit (RU). As an example, a Resource Unit may be based on Orthogonal Frequency Division Multiple Access (OFDMA) technology to divide the communication channel of a wireless network in the frequency domain. The assignment to a non-AP station is signaled to the RU at the beginning of the MU downlink frame by providing an Association Identifier (AID) for each RU defined in the Transmission Opportunity (AID) (which is obtained individually by each station during its association process with the AP).

[0007] The 802.11ax standard also allows Access Points (APs) to trigger MU uplink (UL) transmissions upon winning access to the wireless medium. During MU UL transmissions, various non-AP stations can simultaneously transmit data to the AP on resource units forming the communication channel. To control MU UL transmissions by non-AP stations, the AP previously sends a control frame called a trigger frame (TF). The trigger frame uses a 16-bit Association Identifier (AID) assigned to a non-AP upon registration with the AP and / or a reserved AID specifying a set of non-AP stations to allocate resource units to non-AP stations within the same BSS. The TF also defines the start and length of MU UL transmissions by non-AP stations.

[0008] Recently, the IEEE 802.11be draft standards task group proposed the so-called multi-AP technology. The latter aims to provide a degree of cooperation between adjacent access points (APs managing individual BSSs) to more efficiently utilize available time, frequency, and spatial resources. This is particularly important when adjacent APs operate on the same selected communication channel (or channels close enough to communicate with each other).

[0009] Using this technology, two or more adjacent APs can share resources in terms of frequency and / or time, and in this way, they prevent interference.

[0010] An AP used to initiate and manage multi-AP collaboration by sharing the resources of a licensed TXOP is called a sharing or coordinating AP. The coordinating AP maintains a candidate set of APs that registers candidate APs that have requested to become part of the set to participate in the collaboration. Such an AP participating in multi-AP collaboration and using shared resources is called a shared or coordinated AP. The corresponding BSS is called a coordinated BSS.

[0011] Coordinating APs typically send sharing announcement frames that define which resources are allocated to which coordinated APs. Trigger frames may also be used. Coordinating APs can schedule MU downlink (DL) and / or uplink (UL) transmissions for their associated non-AP sites within constraints (typically in terms of frequency and time) of the resources they are allocated. Multi-AP cooperation is preferably dynamic, meaning that different APs within the same multi-AP group can act as coordinating APs to acquire radio media and share resources.

[0012] In a multi-AP scheme, the resources shared with the coordinated AP may not include the primary channel of the coordinated BSS. To enable the coordinated AP to efficiently schedule MU DL or UL transmissions within the shared resources, all stations on the coordinated BSS need to temporarily switch from their local primary channels to another channel on the shared resources used by the coordinated AP to manage MU transmissions, until the shared TXOP ends. However, some non-AP stations on the shared BSS may be outside the range of the coordinating AP and therefore may not receive the shared advertisement frames. Consequently, these non-AP stations will be unable to switch their primary channels to the correct channel and therefore cannot participate in any MU transmissions initiated by the local APs to which they are registered within the shared resources.

[0013] The contribution of IEEE 802.11-20 / 0277r1 to the 802.11be standard discloses that a coordinated AP may need to instruct its associated non-APs to perform temporary channel switching to operate correctly during shared opportunities. These coordinating APs simultaneously transmit the same exchange frames. The latter only includes the information necessary for the non-APs on their BSS (such as the bandwidth of the primary channel and shared resources), and the TA field in the MAC header must be set to the MAC address of the coordinating AP.

[0014] The first problem with this approach is that coordinated APs (especially if they rely on hardware built by different companies) struggle to build identical switching frames locally. In practice, coordinated APs must organize the same basic information in the same order within the switching frame. However, the order of some information, such as user information fields (defining RUs and corresponding assignments to stations), is not imposed on the device; it depends solely on the AP's implementation.

[0015] The second problem with known multi-AP schemes is that the coordinated AP needs to share the coordinating AP's MAC address a priori with its associated non-AP stations (e.g., during association). This is so that these non-AP stations can efficiently decode exchange frames with a TA that has the same MAC address as the coordinating AP. Therefore, the coordinating AP must be known to all stations, which means the coordinating AP must be fixed.

[0016] The goal is to design a more efficient mechanism for multi-AP operations with stations that are outside the designated range. Summary of the Invention

[0017] The broad objective of this invention is to overcome some of the aforementioned problems.

[0018] In this context, the present invention provides a communication method in a wireless network, comprising performing the following steps at a wireless device:

[0019] The coordinator device that has been granted a transmission opportunity (TXOP) receives a frame for announcing the sharing of resources for the granted TXOP. The announcement frame consists of a short start portion and a large data portion; and

[0020] In response to receiving the notification frame, a re-notification frame is sent that repeats the large data portion of the received notification frame.

[0021] This resource sharing can benefit any wireless device outside the coordinator device's BSS (e.g., other APs).

[0022] The wireless device involved in this method, namely the coordinated device managing a group of wireless devices (e.g., a BSS or DirectLink group), constructs a re-advertising frame by binary copying or duplicating the same large data portion as one of the received advertising frames. The operation of constructing the re-advertising frame is then simple and unrestricted by implementation variations from one device to another. This is important because the coordinated device may have very little time (such as SIFS) to generate the re-advertising frame, which occurs, for example, when the coordinated device is allocated a shared resource declared at the very end of the advertising frame. Therefore, the various coordinated devices involved in a multi-AP scheme can construct strictly identical re-advertising frames within a very short time before simultaneously transmitting re-advertising frames.

[0023] Furthermore, by repeating the large data portion, the coordinated device allows out-of-range devices (from the coordinator's perspective, such as access points, APs) to eventually know about multi-AP resource sharing. Therefore, they can temporarily switch their primary channel if needed.

[0024] The present invention also provides a communication method in a wireless network, comprising the following steps performed at a coordinator device:

[0025] A frame is sent to grant a transmission opportunity (TXOP), the frame also announcing the sharing of resources for the granted TXOP and including a re-announcement field indicating whether at least one coordinated device in relation to the resource sharing must re-announce the resource sharing. The announcement frame includes a short start portion and a large data portion; and

[0026] A re-announcement frame is received from one or more coordinated devices to repeat the big data portion of the sent announcement frame.

[0027] Therefore, for example, when it is realized that some devices involved in resource sharing (i.e., devices allocated shared resources) may be beyond the scope of the initial announcement frame, the coordinator device efficiently drives the re-announcement of resource sharing.

[0028] In addition, by receiving re-announcement frames from the coordinated device, the coordinator device confirms that the coordinated device is operating in an appropriate manner.

[0029] Relatedly, the present invention also provides a wireless communication device including at least one microprocessor configured to perform the steps of any of the methods described above.

[0030] Optional features of embodiments of the present invention are defined in the appended claims. Some of these features are explained below with reference to the method, and some of these features can be converted into apparatus features.

[0031] In some embodiments, the large data portion is the MAC payload of the announcement frame. In this case, the entire MAC payload remains intact (a binary copy), and the re-announcement frame only has a different (shorter) MAC header to be generated. This is the shortest and safest way to generate a re-announcement frame.

[0032] In other embodiments, the re-announcement frame has one or more start fields in the MAC header and MAC payload that differ from the announcement frame. The remainder of the MAC payload remains unchanged. This allows the coordinated device to add signaling notifications when needed.

[0033] In some embodiments concerning the coordinated device, a re-announcement frame is also sent in response to determining from a received announcement frame that the shared resources allocated to the wireless device do not contain the wireless device's primary channel. In other words, the coordinated device only retransmits the large data portion or MAC payload when it must switch its primary channel.

[0034] In some embodiments, a re-announcement frame is also sent in response to a re-announcement field in a received announcement frame indicating that the radio device must re-announce the resource share. In this way, the coordinator device can be driven efficiently when re-announcement is required, possibly based on individual coordinated devices.

[0035] Based on specific characteristics, the re-announcement field indicates that a wireless device that must switch its primary channel must re-announce resource sharing.

[0036] In some embodiments, a wireless device is a management device that manages a group of wireless devices, such as an AP that manages a BSS or a group owner that manages a peer-to-peer (P2P) group that implements DirectLink transmission.

[0037] In some embodiments, the re-announcement frame may include an empty transmitter address (TA) field or omit the TA field in its MAC header. For example, the re-announcement frame may simply be a copy of the received announcement frame in which the transmitter address (TA) field in the MAC header is cleared.

[0038] This approach advantageously avoids having a fixed coordinator device that each and every station must know. Instead, an empty TA field allows any AP to operate dynamically as a coordinator shared by multiple APs (as opposed to known techniques that signal the coordinator AP's MAC address in the TA field).

[0039] Furthermore, the empty TA field is a clear indication for the radio device that the frame is a re-advertising frame. The radio device can act accordingly (e.g., analyze the MAC payload to determine if a primary channel handover is needed, or to initiate MU UL or DL ​​transmission after SIFS).

[0040] In some embodiments, the wireless device is an access point (AP) that also transmits trigger frames on shared resources allocated to the AP to trigger multi-user uplink transmissions on the allocated shared resources with non-AP stations of its own basic service set.

[0041] In some embodiments, the wireless device is an access point (AP) that also initiates multi-user downlink transmissions on allocated shared resources with non-AP stations of its own basic service set. For example, the multi-user downlink transmissions may include indications of subsequent multi-user uplink transmission opportunities on the allocated shared resources.

[0042] In some embodiments, the wireless device also sends frames to announce the sharing of a portion of the shared resources allocated to the wireless device. This sub-sharing of resources can be made to benefit other wireless devices outside its own BSS, such as other APs, including APs that are outside the transmission range of the coordinator device.

[0043] In some embodiments of the coordinator device, the re-announcement field indicates that a coordinated device that must switch its primary channel must re-announce resource sharing.

[0044] In some embodiments, a re-announcement field is provided at the shared resource (e.g., RU) level (e.g., at the user information field level in the trigger frame). This is intended for the coordinator device to selectively select which coordinated device must send a re-announcement frame.

[0045] In other embodiments, the coordinator device may also send re-announcement frames simultaneously to one or more coordinated devices.

[0046] Another aspect of the invention relates to a non-transitory computer-readable medium storing a program that, when executed by a microprocessor or computer system in a wireless device, causes the wireless device to perform any of the methods defined above.

[0047] 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, which are generally referred to herein as “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.

[0048] Because 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

[0049] Embodiments of the invention will now be described by way of example only and with reference to the following figures, in which:

[0050] Figure 1 An exemplary network environment in which embodiments of the present invention can be implemented is shown;

[0051] Figure 2 This illustrates multi-user (MU) transmission based on trigger (TB);

[0052] Figure 3 The structure of the trigger frame is shown;

[0053] Figure 4a The format of HE SU PPDU is shown;

[0054] Figure 4b The format of HE MU PPDU is shown;

[0055] Figure 4c The format of HE TB PPDU is shown;

[0056] Figure 5 The transmission sequence for implementing multi-AP technology to achieve coordinated OFDMA resource sharing is shown;

[0057] Figure 6a A schematic representation of a communication device according to an embodiment of the present invention is shown;

[0058] Figure 6b A schematic representation of a wireless communication device according to an embodiment of the present invention is shown.

[0059] Figure 7 Another multi-AP-based transmission sequence for implementing embodiments of the present invention is shown;

[0060] Figure 8 A flowchart illustrates the general steps at the coordinator device according to an embodiment of the present invention.

[0061] Figure 9 A flowchart illustrates the general steps at a non-coordinator device according to an embodiment of the present invention; and

[0062] Figure 10 An alternative multi-AP-based transmission sequence for implementing embodiments of the present invention is shown. Detailed Implementation

[0063] 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 (TDMA) 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 (i.e., wireless devices or stations). 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 can also be called frequency modulation, frequency bands, 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.

[0064] The teachings of this document can be incorporated into various devices (e.g., stations) (e.g., implemented within the device or performed by the device). In some aspects, a wireless device or station implemented according to the teachings of this document may include an access point (so-called AP) or may not include an access point (so-called non-AP station or STA).

[0065] 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 (“BTS”), base station (“BS”), transceiver function (“TF”), radio router, radio transceiver, basic service set (“BSS”), extended service set (“ESS”), radio base station (“RBS”), or certain other terms.

[0066] 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 certain other terms. 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 certain 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, such as wide area networks (e.g., the Internet or cellular networks), via wired or wireless communication links.

[0067] Figure 1 An exemplary network environment in which embodiments of the present invention can be implemented is shown.

[0068] The wireless network environment shown includes a multi-AP system 100 formed by a group of adjacent wireless networks operating on a common communication channel or wireless medium. The common communication channel may correspond to a portion (e.g., 20 MHz) or all of the operating channel (e.g., 20 MHz, 40 MHz, 80 MHz, or 160 MHz).

[0069] The first wireless network BSS1 includes an access point (AP) 110 and three non-AP stations (STAs) 111, 112, and 113 associated with (i.e., registered with) AP 110. The second wireless network BSS2 includes an AP 120 and three associated non-AP STAs 121, 122, and 123. The third wireless network BSS2 includes an AP 130 and three associated non-AP STAs 131, 132, and 133. In the following text, BSSx represents any wireless network, while 1x1, 1x2, and 1x3 represent any non-AP station. Of course, other numbers of wireless networks and any number of non-AP stations for each wireless network can be considered. In this invention, APs 110, 120, and 130 are also referred to as AP1, AP2, and AP3, respectively. A device can act as an AP in one wireless network and simultaneously belong to another wireless network as an associated STA.

[0070] Each station (AP and non-AP) in the wireless network exchanges data frames on communication channel 100 under the management of the AP. A primary channel, typically a 20MHz channel, is defined for each wireless network exchanging management frames. Other 20MHz channels (if present) in the communication channel are called secondary channels.

[0071] Furthermore, direct communication (also known as direct link, DiL) between non-AP STAs can be achieved without the use of an access point (referred to as Ad-hoc mode). For example, the WiFi Direct standard allows devices to communicate directly over the 802.11 wireless medium without the need for any access point. An exemplary case of direct communication (corresponding to the current growth trend) is point-to-point (P2P) transmission between non-AP stations (e.g., STA 112 and STA 113 shown in the figure) that share the same primary channel. Besides WiFi Direct, technologies that support P2P transmission between non-AP STAs not associated with the same BSS or not associated with a BSS include, for example, WiFi-Miracast (RTM) and wireless display scenarios. Other technologies that support P2P transmission within a BSS include Direct Link Establishment (DLS) and Tunneled Direct Link Establishment (TDLS). Even though P2P streams are typically not numerous, the amount of data per stream (typically low-compressed video ranging from 1080p60 to 8K UHD resolution) is often significant.

[0072] Each non-AP STA 1x1 through 1x3 registers with AP 1x0 of a wireless network BSSx during the association process. During the association process on the primary channel, the AP assigns a specific association identifier (AID) to the requesting station. For example, the AID is a 16-bit value that uniquely identifies the station.

[0073] Stations (including access points) compete with each other on communication channels (including the primary channel and optional secondary channels to increase bandwidth) using EDCA (Enhanced Distributed Channel Access) to gain access to the communication channel and be granted a Transmission Opportunity (TXOP). The TXOP can then be used to transmit (single-user, SU) data frames or to implement multi-user (MU) transmissions. In the MU scheme, a single station (typically an AP in a wireless network BSSx) is allowed to schedule multiple simultaneous transmissions to or from other stations in the wireless network. One implementation of this MU scheme is, for example, adopted in the IEEE 802.11ax revision standard as the Multi-User Uplink and Downlink OFDMA (MU UL and DL OFDMA) procedure. In the MU scheme, resources, called resource units, are defined on one or more 20MHz channels used.

[0074] More generally, resources can include spatial, frequency, and temporal resources, and can be obtained according to different multiplexing schemes. Examples of these schemes 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.

[0075] In the IEEE 802.11 wireless LAN standard, a multi-AP system 100 can correspond to an Extended Service Set (ESS), and each wireless network can correspond to a Basic Service Set (BSS).

[0076] Although embodiments of the invention are described in the context of IEEE 802.11, the embodiments are not limited thereto, and the embodiments can be applied to other types of wireless networks and protocols.

[0077] Figure 2 The MU scheme in any wireless network BSSx is illustrated, and more specifically, trigger-based (TB) multi-user (MU) transmissions are shown, which include MU transmissions between non-AP STAs, i.e., direct link (DiL) transmissions, in addition to MU uplink (UL) transmissions to the APs of the BSSx.

[0078] The illustrated MU transmission is triggered by a trigger frame (TF) 210 that reserves a communication channel for a transmission opportunity (TXOP) 200. The TF is, for example, a control frame in the IEEE 802.11 legacy non-HT format. When idle is detected, the APx transmits the TF on the primary 20MHz channel 250 and copies (repeates) the TF on one or more other (secondary) idle 20MHz channels 251 (if present) that form the communication channel. Due to the copying of the control frame 210, each nearby legacy station (non-HT or 802.11ac station) that receives the TF on the primary channel (which may be a secondary channel of the BSSx under consideration) is expected to set its NAV to the value specified in the header of the TF. This prevents these legacy stations from accessing the reserved communication channel during a transmission opportunity (i.e., TXOP).

[0079] TF 210 has Figure 3 The structure shown is a MAC (Media Access Control) frame 300 composed of the following items:

[0080] The MAC header 310 includes a standardized "Frame Control" field 311, a standardized "Duration" field 312 defining the duration of a transmission opportunity (e.g., TXOP 200), an "RA" field set to the broadcast MAC address of BSSx 313, and a "TA" field set to the MAC address of the AP that triggered the transmission frame 314.

[0081] MAC payload 320.

[0082] MAC payload 320 includes:

[0083] Field 330, "Public Information"

[0084] One or more “User Information” fields 340, and

[0085] Fill and FCS fields.

[0086] The "Public Information" field 330 includes a "Trigger Type" subfield 331, which specifies the type of trigger frame. Currently, eight values ​​(0 to 7) are defined. For example, a value of 0 in the "Trigger Type" subfield 331 is used to signal the basic TF.

[0087] The "Public Information" field 330 also includes a "UL Length" field 332 specifying the duration of the requested UL transmission (preamble 230 + UL data 221), and a two-bit "UL BW" field 333 specifying the bandwidth of the communication channel under consideration, for example, BW=0 for a 20MHz bandwidth, BW=1 for a 40MHz bandwidth, BW=2 for an 80MHz bandwidth, and BW=3 for an 80+80MHz or 160MHz bandwidth. The "Public Information" field 330 ends with a reserved B63 bit 334 and a variable-length trigger-related public information subfield 335 (the content of which depends on the "Trigger Type" subfield 320).

[0088] like Figure 2 As shown, the basic communication channel is defined across the communication channels used, here referred to as the resource unit (RU). Essentially, each resource unit is assigned to a different non-AP station within the MU scheme.

[0089] Resource units RU1 201 to RU8 208 (more generally, RUx) are formed by a preferably adjacent set of subcarriers contained in a communication channel. This means that the frequency bandwidth of the communication channel is greater than or equal to the frequency bandwidth of the resource unit. RUs can be allocated for scheduled access (AP decides which non-AP station uses the RU) or random access (non-AP stations compete for access to the RU).

[0090] RU is defined by AP in TF 210. Return to Figure 3 Each "User Information" field 340 corresponds to one of the RUs. The "User Information" fields 340 can be used in any order within the TF 300, as these fields self-containedly define the RU and its access scheme.

[0091] The “User Information” field 340 includes the “AID12” subfield 341, the “RU Allocation” subfield 342, and ends with a reserved B39 bit 343 and a variable-length “Trigger-Related User Information” subfield 344 (the content of which depends on the “Trigger Type” subfield 320). There are other fields that are not described here for the sake of brevity.

[0092] The “AID12” subfield 341 is set to the AID of the non-AP station to which the RU defined in the “RU allocation” subfield 342 is assigned in the case of scheduled access, or it is set to AID = 0 or 2045 to provide the corresponding RU to random access of associated and unassociated non-AP stations, respectively. The 802.11ax standard (e.g., Table 9-31g of version D4.1 of this standard) defines the values ​​to be used in the “RU allocation” subfield 342 to specify a particular RU within the communication channel signaled in the “UL BW” field 333.

[0093] exist Figure 2 In the example, TF 210 provides RUs (RU1 201 and RU3 to RU8 203 to 208) to non-AP stations for uplink (UL) transmission 221, and provides DiL transmission capability 222 within the triggered MU transmission by allocating resource units (here, RU2 202) for this purpose. Previously, the P2P group manager or responsible party or "group owner" may have informed the AP that the P2P group is willing to have new opportunities for DiL transmission.

[0094] By using the appropriate value in the “AID12” subfield 341, the DiL transmission provided by the AP can be signaled in the associated “User Information” field 340 (i.e., the field corresponding to the provided RU).

[0095] In one implementation, the "AID12" subfield 341 can transmit a DiL session identifier corresponding to a direct link session (the source and destination stations involved in direct link communication can be directly identified). This is envisioned when the AP has permitted the P2P session (such as the DLS protocol (if within its BSS)) or alternatively is aware of the P2P protocol (outside its BSS and discovered via a coordination scheme beacon frame or discovery frame) and has granted a session permission identifier. Preferably, the DiL session identifier is restricted to a 12-bit AID format; the AP then assigns a value different from the AID value assigned to identify each non-AP station.

[0096] Alternatively, the "AID12" subfield 341 can transmit the AID of a non-AP station in the P2P group (e.g., the group owner of the P2P group). Alternatively, since non-AP 802.11ax stations in the P2P group may not know the AID, a MAC address can be used instead of the station identifier (AID), as this address is generally known and more specifically shared by the AP and the station. In a variant, the two AIDs (if present) or two MAC addresses of the non-AP stations involved in the DiL session can be indicated in the user information field (using, for example, the AID12 subfield 341 and / or triggering the relevant user information section 344).

[0097] Return to Figure 2 As a result of receiving TF 210, non-AP stations begin MU transmission (for UL or DiL transmission) at SIFS following TF. Non-AP stations begin sending their data frames in the High Efficiency (HE) format introduced in 802.11ax.

[0098] High-efficiency (HE) frames have been introduced in 802.11ax. For example... Figure 4a , 4bAs shown in 4c, these frames begin with the same preamble 230 (L-STF, L-LTF, and L-SIG) readable by any station (for backward compatibility) and continue with complementary preamble and data fields. The HE field of the preamble can only be decoded by 802.11ax (and forward compatible) devices and is included in various types of HE frames, such as HE single-user (SU) PPDUs for single-user transmissions, HE MU (multi-user) PPDUs for transmissions to one or more stations (particularly for MU downlink (DL) transmissions from AP to non-AP stations), and HE trigger-based (TB) PPDUs (HE_Trig) for uplink (UL) transmissions from non-AP stations to APs in response to trigger frames.

[0099] Figure 4a , 4b Figures 4c and 4c illustrate the formats of these various frames (HE SU PPDU, HE MU PPDU, and HE TB PPDU frames). These HE frames are used as examples in describing embodiments of the invention. However, other formats are of course contemplated. For example, the Extremely High Throughput (EHT) frames introduced in 802.11be are also well-suited for use.

[0100] Figure 4a The format of the HE SU PPDU is shown. It includes a conventional preamble (L-STF, L-LTF, L-SIG with RL-SIG), an HE preamble consisting of HE-SIG-A (HE signal A), HE-STF (HE short training field), and HE-LTF (HE long training field), and ends with data and PE (packet extension) fields. The conventional preamble and HE-SIG-A (together referred to as field 400a) are copied on each 20MHz channel used in the communication channel. The HE-SIG-A field includes several subfields that indicate the set of transmission parameters of the PPDU, such as bandwidth (BW), modulation and coding scheme (MCS), number of data streams, coding type, etc. The next field 401a is modulated on the channel bandwidth.

[0101] Figure 4b The format of HE MU PPDU is shown. It includes HE SU PPDU ( Figure 4aThe same field, with an additional field 401, namely HE-SIG-B (HE Signal B), is used to tell non-AP stations in which resource unit they will find their data (i.e., RU allocation to non-AP stations). This is because the DL transmission starts directly without a prior trigger frame for announcing the RU allocation. Therefore, HE-SIG-B 401 defines how the RUs forming the DL MU transmission are assigned to non-AP stations so that the latter can efficiently receive their own data from the AP. Again, field 400b is replicated on each of the 20MHz channels, while for field 401b, HE-STF and HE-LTF are modulated over the channel bandwidth, and the data is modulated only on the RUs involved.

[0102] Figure 4c The format of HE TB PPDU (HE-Trig) is shown. This is used for Figure 2 The data frame (preamble 230 and data 221) follows this format. Each HE-Trig PPDU carries a single transmission in response to the trigger frame (i.e., from a non-AP station). The HE-Trig frame has a format very similar to the HE SU PPDU, except that the duration of the HE-STF field is 8 μs. In particular, the HE-SIG-B field is not included because the RU allocation to non-AP stations has been defined by TF 210. Again, field 400c is replicated on each 20MHz channel, while for field 401c, HE-STF and HE-LTF are modulated over the channel bandwidth, and data is modulated only on the relevant RU.

[0103] If DiL occurs on the entire 20MHz channel or a multiple thereof, the DiL transmission is based on the HE SU PPDU format; or if the transmission occurs on a sub-part of the 20MHz channel, the DiL transmission is based on the HE TB PPDU format.

[0104] The standard MU transmission mandates that the preamble 230 be identical for all transmissions. More precisely, for 802.11ax, the pre-HE modulation field 400c (constituting preamble 230) must be exactly the same and transmitted simultaneously on each of the respective 20MHz bands of the communication channel used. This includes preambles for DiL transmissions from non-AP stations to destination DiL non-AP stations.

[0105] Once a station has transmitted data to the AP using scheduled and / or random RUs, the AP responds with a multi-user acknowledgment to acknowledge the data received on each RU. The acknowledgment frame 240 may follow the NON_HT PPDU format (241) for block acknowledgment, or follow the HE MU PPDU format (242) for RU-based acknowledgment when transmitted on an OFDMA RU.

[0106] For DiL transmissions, it can be envisioned that the destination DiL non-AP station transmits an acknowledgment frame 260 on the same RU as the RU used for DiL transmission 222. The acknowledgment frame 260 may follow the SU format ( Figure 4a ).

[0107] Multi-AP technology has emerged, in which once one of APs 110, 120, and 130 is granted access to a common communication channel, APs 110, 120, and 130 cooperate to share the common communication channel. The APs exchange messages with each other to coordinate multi-AP communication, thereby avoiding interference.

[0108] Multi-AP sharing of a public communication channel is resource-based. The amount of shared resources can be measured in units of time, bandwidth, number of streams, amount of data or traffic (e.g., number of bytes), and / or any other suitable unit, depending on the type of resource as defined above. For example, resources such as... Figure 2 The frequency organization shown implies that the first AP can provide one or more RUs to other APs. From this perspective, "shared resources," "shared band," "shared channel," and "shared resource unit" are synonyms and specify these resources provided by the coordinator AP to another AP through multi-AP technology.

[0109] To coordinate multi-AP communication, APs can be part of an inter-AP coordination group, the formation of which is outside the scope of this invention. As an example, APs willing to cooperate may previously publish management frames, such as beacon or dedicated broadcast frames, to advertise their multi-AP coordination capabilities to other APs. The coordination group is also referred to as a set of AP candidates for multi-AP sharing.

[0110] Figure 5 The transmission sequence for implementing multi-AP technology to achieve coordinated OFDMA resource sharing is shown. The transmission sequence is based on 802.11ax frames. However, equivalent frames can be used.

[0111] The trigger frame 210 has a non-HT copy format and is copied on each of the 20MHz channels (e.g., 40MHz for illustration) that form a common communication channel.

[0112] Trigger frame 210, sent from the coordinator or “sharing” AP (AP1 for illustration), is configured to trigger a MU transmission for another wireless network (BSS2 managed by AP2 for illustration), i.e., to initiate multi-AP coordination to share a portion of the TXOP with other BSSs. To this end, trigger frame 210 allocates one or more resource elements (here, a single resource element RU5 with a 20MHz width) of a reserved communication channel to the other wireless network. From this perspective, trigger frame 210 acts as a frame announcing the sharing of the permitted TXOP resources.

[0113] In the exemplary sequence shown, TF 210 sent by AP1 allocates resource elements of its primary 20MHz channel to a non-AP STA (STA) of its own wireless network (i.e., BSS1). 11 STA 12 STA 13 STA 1i Therefore, the regular MU UL transmission 221 occurs on the BSS's main 20MHz channel: each non-AP STA (STA 11 STA 12 STA 13 STA 1i According to HE TB PPDU format ( Figure 4c Transmit UL frames, in which all pre-HE modulation fields 400c (forming preamble 230) are transmitted only by these stations on the main 20MHz channel.

[0114] In addition to the regular MU UL RU, one or more resource units of the MU transmission are allocated to another wireless network (BSS2 in this example) managed by another AP (AP2). From the perspective of the coordinating AP, this other AP (AP2) is considered a purely physical device, such as a station unassociated with the coordinating AP (AP1), i.e., it typically does not have an AID assigned to it by the coordinating AP. This other AP is called the coordinated or "shared" AP and will manage the shared resources allocated to its BSS by the coordinating AP.

[0115] AP1 signals the resource unit in TF 210 to notify the coordinated AP (AP2) of its allocation. Since AP2 does not have an AID known to AP1, a special identifier can be used to populate the "AID12" subfield 341 of the corresponding "User Information" field 340. For example, the MAC address of the coordinated AP or the BSSID of the coordinated BSS can be used to signal the resource unit that it has been allocated to the coordinated AP / BSS (AP2 / BSS2).

[0116] Each of these allocated resource units occupies a frequency band consisting of multiple 20MHz channels (e.g., 20, 40, 60, 80MHz, etc.). In other words, multi-AP technology preferably leases 20MHz channels. The shared frequency band can be continuous or perforated, and can be adjacent to or not adjacent to the main channel of BSS1.

[0117] As mentioned earlier, each wireless network BSSx defines its own primary 20MHz channel, on which stations within the network compete. The shared frequency band may or may not include the primary 20MHz channel of the coordinated BSS (here, BSS2). When the shared frequency band does not include BSS2's primary 20MHz channel, AP2 and non-AP stations of BSS2 must temporarily switch their primary 20MHz channels (until resource sharing ends) to communicate efficiently together on that shared frequency band.

[0118] The “new” (and temporary) primary 20MHz channel for the coordinated BSS (BSS2) can be defined by the coordinator AP (AP1) in TF210 (using appropriate flags), or by rules known to all stations of the coordinated BSS.

[0119] The coordinated AP (AP2) uses the resource units of MU transmission allocated to its BSS (RU5 in this example) to manage data exchange within its BSS (BSS2), particularly data exchange between non-AP stations of BSS2 and AP2.

[0120] Recursively, AP2 can sublease one or more 20MHz channels of the shared resource unit thus acquired to stations outside BSS2, such as to another AP (e.g., AP3). In this case, AP2 becomes the coordinating AP for AP3. As an example, when the coordinated device (AP2) is the BSSID AP transmitting for the physical AP, it can further allocate a portion of the shared frequency band to its untransmitted BSSIDs.

[0121] When managing data exchange within a shared resource for coordinated transmission, the coordinated device can transmit data frames using single-user (SU) format because the shared bandwidth consists of one or more entire 20MHz channels. However, it can also use multi-user (MU) format or a combination of both to transmit data frames. The SU format used can be the HE SU PPDU format according to the IEEE 802.11ax standard. Figure 4a The MU format used can be HE MU PPDU format according to the IEEE 802.11ax standard. Figure 4b(Alternatively, the EHT MU PPDU format can be envisioned based on the IEEE 802.11be standard.) In the MU format, the frame (preamble) has an HE-SIG-B field containing additional information (such as the transmitter's identifier, i.e., the coordinated AP) that can be used by the frame's receiver to quickly (i.e., even before receiving the frame's data field) determine the PPDU's transmitter. This helps non-AP stations correctly identify whether a frame must be processed (if the frame originates from a local AP).

[0122] For example, refer to Figure 2 The MU scheme described can be implemented within these shared resource units (RU5 in this example).

[0123] Therefore, the coordinated AP (AP2) sends a trigger frame 510 (in SU or MU format) to trigger a (second) MUUL transmission from a non-AP station of the second BSS (BSS2) on the allocated shared resource unit of the (first) MU transmission triggered by the coordinating AP (AP1). The coordinated AP (triggered by AP1 via TF 210) becomes the triggering AP for the non-AP station of BSS2. TF 510 defines its own duration 312 (within the TXOP limit defined by the duration 312 of TF 210) and its own UL length 332 for the MU UL transmission 530 of the non-AP station of BSS2.

[0124] Since the coordinated AP (AP2) is the only transmitter in the 20MHz channel forming the shared frequency band (when not subleased), the preamble 500 (preamble TF 510) transmitted by the coordinated AP on the 20MHz channel is not superimposed on the preamble 230 transmitted by the STA of BSS1 in other 20MHz channels (simultaneously).

[0125] Next, the non-AP station of BSS2 receives TF 510 transmitted by AP2 and determines from TF 510 whether it has been allocated a RU (RU5 in this example) within the shared frequency band. Note that the RU defined in TF 510 is included within the shared RU defined in TF 210, and can be a sub-part of the shared RU defined in TF 210. The non-AP station of BSS2 can then transmit its triggered UL frame 530 (with preamble 520).

[0126] The MU downlink frame (550 (together with its preamble 540)) can also be transmitted in a shared frequency band licensed by AP1, where AP2 can send several AMPDUs to multiple non-AP stations of its BSS (BSS2).

[0127] The PHY preamble 500-520-540 can have the same frequency width as the related data 510-530-550, which is 20MHz in this example.

[0128] like Figure 5 As shown, MU transmissions within the coordinated BSS (BSS2) can be shorter in time than MU transmissions within the coordinating BSS (BSS1) (see shaded area). In this case, the coordinated AP (AP2) can send a padding signal to maintain energy on the shared band across the entire TXOP.

[0129] When the MU transmission in the shared band ends, the station in the coordinated BSS (BSS2) switches back to its original primary 20MHz channel (if a temporary switch has already been performed).

[0130] A key requirement for the efficient operation of this coordinated multi-AP scheme is the active reception of trigger frames by all participants (including the coordinated AP and its associated non-AP stations).

[0131] However, some non-AP stations under the coordinated BSS (e.g., stations managed by AP2 in BSS2) may be outside the transmission range of the coordinator AP (AP1) and therefore may not receive the initial TF 210.

[0132] This shouldn't be a problem for these BSSs to be allocated a shared frequency band containing their primary 20MHz channel. In fact, in this case, the coordinated AP (AP2) still transmits TF 500 in the primary channel of the coordinated BSS (BSS2), and non-AP stations outside the range of that BSS are able to receive TF 500 and thus know the upcoming MU sequence.

[0133] However, this is different when the allocated shared frequency band does not include the primary 20MHz channel of the coordinated AP (AP2). This is because a temporary handover is required from the station of the coordinated BSS (BSS2) to receive further communication from the coordinated AP (specifically, trigger frame 510). However, non-AP stations outside the range of this BSS cannot be aware of this handover without receiving the initial TF 210. Therefore, these non-AP stations cannot participate in the coordinated TXOP, and in particular, cannot receive TF 500 sent by their local AP (the coordinated AP, AP2) through the primary 20MHz channel after the handover.

[0134] An enhanced multi-AP scheme is proposed to overcome this problem. It is easy to implement at the coordinated AP and provides flexible multi-AP sharing.

[0135] The enhancement scheme, at the coordinated AP (and more generally at the coordinated device) and in response to the reception of TF210 (i.e., the advertised resource sharing frame), provides the transmission of a re-advertising frame that repeats the MAC payload of the received advertised frame or repeats the short start portion of the advertised frame (e.g., one or more start fields in the MAC header and MAC payload) followed by the large final data portion. The short start portion is differentiated so that the station can clearly distinguish between the advertised frame and the re-advertising frame. This is important to ensure that station operation meets sequence timing (e.g., MU transmission begins at SIFS after the re-advertising frame).

[0136] Re-announcement ensures that all stations under the coordinated BSS (i.e., including out-of-scope stations) become aware of the resource sharing defined in the MAC payload (from the initial / announcement TF 210).

[0137] Furthermore, simply repeating or copying the MAC payload, or most of it (i.e., the common and fixed payloads), keeps the operational complexity at the coordinated AP very low. This is well-suited to the very short time they have when receiving the initial / announcement TF 210 (SIFS guaranteed only).

[0138] Therefore, non-AP stations of the coordinated BSS receive a re-advertising frame from the coordinated AP (AP2) that is separated from the coordinating AP (AP1). This re-advertising frame announces the shared Transmission Opportunity (TXOP) resources granted to the coordinating device. Then, in response to receiving the re-advertising frame, they switch their primary channel to the operating channel of the shared resources. Thus, the operating channel becomes the primary channel of the coordinated BSS (temporarily).

[0139] The coordinating AP may send an announcement frame (initial TF) that includes a re-announcement field indicating whether at least one of the coordinated APs must re-announce the resource share in relation to it. The coordinating AP then receives a re-announcement frame from one or more of the coordinated APs, repeating the MAC payload of the previously sent announcement frame or its large final data portion.

[0140] While the above presentation of multi-AP technology focuses on coordinating APs and coordinated APs, the present invention is applicable to any kind of device that operates as a coordinating entity and a coordinated entity.

[0141] Similar to assigning an RU to a DiL transport (see...) Figure 2 (222) In this context, resources can be shared to benefit P2P groups, which can organize themselves to perform DiL transfers within shared resources. In this case, the coordinated device is a P2P device (not an AP), such as the owner or manager of the P2P group.

[0142] Similarly, any device (not just the AP) can acquire the TXOP and decide how to share it using the proposed mechanism. Therefore, the coordinator device can be different from the AP.

[0143] In other words, besides the coordinated BSS, other communication groups can be considered, such as those mentioned above (see reference above). Figure 2 Introduced direct links are groups of stations communicating. Within this short-range and dynamic network configuration, a single station device can be elected as the group owner and act as the central hub for all P2P communication. Consequently, a multi-AP (shared) scheme can be applied to direct links, where the device elected as the master owner of a given P2P group can have a role equivalent to the coordinated AP role described above for a given BSS.

[0144] Therefore, in the following description, reference is made to the "coordinator device" for an entity that triggers a multi-AP-based coordination scheme and provides shared resources to other groups or BSSs (e.g., coordinator APs or coordinator P2P stations). Accordingly, reference is made to the "coordinated device" for any entity that manages such other groups or other BSSs: for example, a coordinated AP in the context of another BSS or a group owner station in the context of a P2P group.

[0145] Figure 6a A communication device 600 configured to implement at least one embodiment of the present invention is illustrated schematically, for example... Figure 1 Any (AP and non-AP) station shown. Communication device 600 is a coordinating device, a coordinated device, or a purely station managed by a coordinator or a coordinated device.

[0146] The communication device 600 may preferably be a device such as a microcomputer, workstation, or lightweight portable device. The communication device 600 includes a communication bus 613, which is preferably connected to:

[0147] The central processing unit 601, referred to as the CPU, is such as a processor;

[0148] Memory 603 is used to store executable code of a method or steps of a method according to an embodiment of the present invention, and registers adapted to record variables and parameters required to implement the method; and

[0149] At least one communication interface 602 is connected to a wireless communication network, such as a communication network according to one of the IEEE 802.11 standard families, via a transmitting and receiving antenna 604.

[0150] Preferably, the communication bus provides communication and interoperability between various elements included in or connected to the communication device 600. The representation of the bus is not limiting, and in particular, the central processing unit is operable to communicate instructions directly or by means of another element of the communication device 600 to any element of the communication device 600.

[0151] The executable code can be stored in memory, which can be read-only, a hard disk, or a removable digital medium (such as a disk). According to an alternative variation, the executable code of the program can be received via interface 602 through a communication network and stored in the memory of the communication device 600 before being executed.

[0152] 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).

[0153] Figure 6b This is a block diagram schematically illustrating the architecture of a communication device 600 suitable for at least partially implementing the present invention. As shown, device 600 includes a physical (PHY) layer block 623, a MAC layer block 622, and an application layer block 621.

[0154] The task of PHY layer block 623 (here, the 802.11 standardized PHY layer) is to format, modulate, or demodulate any 20MHz channel or common communication channel to transmit or receive frames over the radio medium used, such as 802.11 frames, for example, a Medium Access Trigger Frame (TF) to reserve transmission slots, 20MHz-wide MAC data and management frames for interaction with conventional 802.11 stations, and OFDMA-type MAC data frames with a width less than 20MHz (typically 2 or 5MHz) to / from the radio medium.

[0155] The MAC layer block or controller 622 preferably includes a MAC 802.11 layer 624 that implements conventional 802.11ax MAC operations, and an additional block 625 for at least partially performing the present invention. The MAC layer block 622 may optionally be implemented in software, which is loaded into RAM 603 and executed by CPU 601.

[0156] Preferably, the supplementary block 625 is referred to as the multi-AP notification management module, which has different operations to implement parts of the present invention, depending on the role played by the communication device 600. Since the same device can play different roles at different times, the supplementary block 625 is preferably designed to selectively perform different operations.

[0157] For example, rather than exhaustively, the operation of a communication device acting as a coordinator device may include: selecting a coordinated device (AP or non-AP P2P station); generating an initial trigger frame that announces resource sharing and includes, for example, indications for RU allocation for stations in the same group and for other groups, and indications of which coordinated devices must send re-announcement frames.

[0158] For example, rather than exhaustively, the operation of a communication device acting as a coordinated device may include: receiving a notification (trigger) frame from a coordinator device; determining whether a re-notification frame must be sent, and if so, preparing the re-notification frame by reusing the MAC payload of the notification frame or its large final data portion; and configuring the PHY layer 623 to transmit the re-notification (trigger) frame.

[0159] For example, rather than exhaustively, the operation of a communication device acting as a station in a coordinated group / BSS may include: receiving a re-announcement frame from a coordinated device; retrieving an indication from a received announcement frame or re-announcement frame (if no announcement frame is received) to safely switch its primary channel; and performing regular P2P (DiL) frame switching or MU transmission.

[0160] According to an embodiment of the present invention, the MAC 802.11 layer 624 and the multi-AP announcement management module 625 interact with each other to accurately handle communications addressed to multiple stations on the OFDMA RU.

[0161] In the upper part of this diagram, application layer block 621 runs applications that generate and receive data packets (e.g., data packets such as video streams). Application layer block 621 represents all stack layers above the MAC layer standardized by ISO.

[0162] Embodiments of the invention advantageously incorporate in various aspects the transmission of control frames by one or more coordinated devices, which copy information from the initial trigger frame (the so-called "announcement frame" transmitted by the coordinator device) before the shared RUs issue their HE PPDUs, so that all stations near the coordinated device (particularly those beyond the coordinator's transmission range) can receive this information before the shared RUs begin to be used. When the initial trigger frame signals multi-AP-based resource sharing, all stations that receive the initial trigger frame or a copy thereof become aware of this sharing and can therefore switch their primary channels if necessary. Since most of the resource allocation information forming the initial TF received by the coordinated device is copied as is into the new control frame (the so-called "re-announcement frame"), the coordinated device can achieve correct, fast, and easy copying of each 20MHz channel in a synchronous manner.

[0163] The concept of this invention is based on Figure 7 As shown in the figure, Figure 7An implementation of the present invention is shown. Figure 5 Similar transmission sequences. Figure 8 This is illustrated in particular by means of embodiments of the present invention. Figure 7 A flowchart of the general steps of a communication device that acts as a coordinator during the sequence period. Figure 9 This is illustrated in particular by means of embodiments of the present invention. Figure 7 Another flowchart of the general steps of a non-coordinator communication device (i.e., acting as a coordinated device or acting as a mere station) during the sequence.

[0164] As from Figure 7 As is evident, the initial trigger frame 710 is still transmitted on the communication channel to announce resource sharing based on multi-AP technology. This announcement frame is conceptually equivalent to TF 210 described above, but may optionally include additional instructions, as further described below, to signal when re-announcement by the coordinated device is required.

[0165] TF 710 is followed by a re-advertising frame 720 transmitted by one or more coordinated devices (AP2) in SIFS after the advertising frame 710. Preferably, the re-advertising frame 720 is transmitted by the coordinated device in non-HT copy mode on the same 20MHz channel as for TF 710 (or on all corresponding 20MHz channels matching the bandwidth operation capabilities of the coordinated device). Alternatively, the re-advertising frame 720 may be transmitted on fewer channels, in which case the re-advertising frame 720 is transmitted at least on the coordinated device's primary channel (so that all stations in the same BSS receive the frame) and on channels allocated to the shared frequency band of the coordinated device.

[0166] The re-announcement frame 720 can also be named a "self-triggered frame" because it is intended for use with the BSS set (or group set) of the coordinated device transmitting the frame.

[0167] According to the invention, the re-announcement frame 720 contains the same resource allocation data content as TF 710. In particular, the re-announcement frame 720 may binary repeat or copy the entire MAC payload of TF 710 (or most of it except for one or more start fields), in which all resource allocations (and therefore resource sharing) are defined. This allows all involved stations in the same group / BSS as the coordinated device to receive resource allocations, even if they are outside the transmission range of AP1 and have not received the initial announcement frame 710.

[0168] Advantageously, when several coordinated devices are involved in a multi-AP resource sharing initiated by the coordinator device, these coordinated devices simultaneously transmit the same re-advertisement frame 710 on a 20MHz channel (preferably the same channel) in a non-HT repetition format. Therefore, all stations in their BSS or group become aware of the resource sharing.

[0169] When required by the allocated shared frequency band, the station performs a primary channel handover to the appropriate channel (indicated in frames 710 and 720 or known locally by predefined rules).

[0170] Then, MU transmissions 221 and 510 can begin in SIFS following re-announcement frame 720 (including its preambles 230 and 500). (Previously referenced...) Figure 5 This describes such MU transmission. For example, a coordinated AP can also send a trigger frame on the shared resources allocated to it (or its BSS) to trigger multi-user uplink transmissions on the allocated shared resources with non-AP stations in its own basic service set.

[0171] Furthermore, in embodiments seeking to reduce interference between adjacent 20MHz channels, when preambles 500, 520, and 540 are transmitted across the entire 20MHz band, related data 520, 540, and 560 are transmitted in a narrower band. For example, an empty 26-modulus RU can be defined at one (or both) boundaries of the 20MHz channel (consisting of 242 moduli) (e.g., using AID=2046 in the corresponding user information field 340). The empty RU is shown under reference numeral 599 in the figure; it is the RU closest to the main channel of AP1.

[0172] As described above, the notification TF 710 allocates resources to BSS2 by setting, for example, the BSSID of AP2 in the corresponding “AID12” subfield 341, such as one or more RUs (here, RU5, which defines the shared frequency band).

[0173] In this embodiment, the re-announcement process of the coordinated device (AP2) is systematic for the coordinated device (AP2) that receives the announcement frame 710. In this case, TF 710 can be similar to TF 210 described above.

[0174] This can be applied to direct-link RU communication: simply identifying an RU as a direct-link RU is sufficient to determine that re-advertising is required. Similarly, this can be applied to coordinated APs: simply using the coordinated AP's MAC address or BSSID (or a value derived from it) for RU allocation is sufficient to determine that re-advertising is required.

[0175] In a specific embodiment, only the coordinated device that must temporarily switch its primary channel (for the reasons described above) continues to re-announce the resource sharing for its paired station (so that they also switch). In this case, a re-announcement frame is also sent in response to determining from the received announcement frame 710 that the shared resources allocated to the coordinated device do not include the coordinated device's primary channel (in which case a temporary switch is required).

[0176] In other embodiments, the coordinator device (AP1) may determine when the coordinated devices must send a re-announcement frame 720, and optionally which coordinated devices must do so.

[0177] For example, the coordinator device can know that all stations in the triggered BSS or group are within its transmission range. In this case, all stations will directly receive the advertisement frame 710 and do not need to send a re-advertisement frame 720. This saves the corresponding transmission time +SIFS. This situation typically occurs when the coordinator AP is a transmitting BSSID AP, which shares a portion of its time / frequency TXOP with at least one of its non-transmitting APs (both located within the same physical AP device).

[0178] In this scenario, the initial notification frame 710 may include a renotification field indicating whether at least one coordinated device in relation to the resource sharing must renotify the resource sharing. The coordinated devices only need to read the renotification field of the received notification frames to determine whether they must renotify the resource sharing.

[0179] In a specific embodiment, all coordinated devices may be requested to transmit re-announcement frames. This can be useful when the coordinator device implements a punched TF (due to the detection of some occupied channels that cannot be used for communication TXOPs reserved by the TF).

[0180] In a specific embodiment, only coordinated devices that must temporarily switch their primary channel (for the reasons stated above) are invited to re-advertise resource sharing for their paired stations (so that they also switch). In this case, the re-advertise field indicates that coordinated devices that must switch their primary channel must re-advertise resource sharing.

[0181] For example, the re-advertisement field can allow the coordinating AP to decide between no re-advertisement (field set to 0) and re-advertisement by the switching coordinated AP (field set to 1), or between re-advertisement by all coordinated APs (regardless of the primary channel handover issue) (field set to 0) and re-advertisement by the switching coordinated AP (field set to 1), or even between three options (the re-advertisement field therefore consists of at least two bits).

[0182] Of course, any other conditions can be considered to select a subset of coordinated devices to transmit re-announcement frames. For example, a subset of coordinated devices considered spatially distant from the coordinator device can be selected. Spatial distance can be determined by measuring a low-power signal (compared to a threshold). Such examples aim to extend the protection zone by incorporating stations near these devices.

[0183] More generally, the coordinator device can selectively choose which coordinated devices must send re-announcement frames (e.g., depending on policy rules and / or historical data). In this case, the re-announcement field is preferably provided at the resource level (e.g., at the user information field level in the trigger frame).

[0184] In some embodiments, the re-announcement field is implemented in the trigger type subfield 331 of frame 710. Subfield 331 can be set to a value indicating that the coordination trigger frame needs to be re-announced by the coordinated device. For example, one or more reserved values ​​("8", "9", etc.) can be used.

[0185] In the variant, specific subfields (e.g., a single bit acting as a re-announcement field) can be used as signaling elements for re-announcement requests. Such subfields can simply be named "TF Required," "TF Copy Required," "TF to Self Required," or any other appropriate name.

[0186] In one implementation, bit 39 of field 340 in the 802.11ax user information field... Figure 3 Reference numeral 343 in the accompanying drawings is used for this purpose. Alternatively, one or more bits of the trigger-related user information subfield 344 may be used. Advantageously, such one or more bits at the RU level allow the coordinator AP to selectively choose which coordinated device must re-advertise resource sharing. Furthermore, the use of the RU-level subfield is backward compatible with the existing 802.11ax TF format.

[0187] In another implementation, bits within the common information subfield 330 can be used. Therefore, such signaling is common to all coordinated devices. This bit is preferably applied when all devices with the assigned shared RU (except those of the coordinator BS) are considered coordinated devices.

[0188] As an example, the "CS required" bit can be used ( Figure 3Reference numeral 336 in the figure is irrelevant in the case of trigger frames used for multi-AP technology. In a variant, reserved bit B63 (reference numeral 334) can be used, or any bit or more bits of the trigger-related common information field 335 can be used. This signal notification at the level of common information field 720 is also backward compatible with the existing 802.11ax TF format.

[0189] According to the invention, the re-advertisement frame TF 720 has substantially the same payload content as the initial advertisement frame TF 710. Due to sequence timing (MU transmission begins at SIFS after the re-advertisement frame 720), it is necessary for the re-advertisement frame 720 and the initial advertisement frame 710 to be different, particularly for out-of-range stations to know whether they are currently receiving advertisement frame 710 (in which case re-advertisement frame 720 is expected) or re-advertisement frame 720 (in which case MU transmission will begin after SIFS). Therefore, the short start portions between the two frames 710 and 720 are made different.

[0190] In the first embodiment, where the short start portion consists of one (or two) or more start fields of the MAC header and MAC payload, the trigger type subfield 331 in the common information field 330 can be used to identify a TF-to-itself frame as a new trigger frame variant (using a reserved type value). Therefore, the station only needs to read this subfield 331 to clearly distinguish between TF710 and TF720. In these embodiments, the remainder of the MAC payload (defining RU allocation, including resource sharing) can remain unchanged. Optionally, the next field, the UL length subfield 332, can be adjusted.

[0191] In the second embodiment, the re-announcement frame 720 includes an empty transmitter address (TA) field (i.e., a value of 0 or NULL) or excludes the TA field in its MAC header. This can be advantageously used when the entire MAC header is binary copied in the re-announcement frame 720. In this case, creating the re-announcement frame at the coordinated device is very simple and fast (only the SIFS duration is guaranteed for frame creation): only the received announcement frame 710 is copied, where the transmitter address (TA) field in the MAC header is cleared or deleted. This can also be used in conjunction with the first embodiment described above, which modifies one or more start fields of the MAC header.

[0192] These embodiments allow any station to dynamically act as a coordinator device because there is no need to identify the coordinator device in the frame. Therefore, the sharing scheme proposed in this invention is completely flexible.

[0193] Note that, for consistency between the durations set in the re-announcement frame 720 and the initial announcement frame 710, it is preferable (but not mandatory) that the re-announcement frame 720 instructs the lower duration timer (in the duration field 312) to again retain the same call duration as the initial announcement frame 710. For consistency, the duration field 312 specified in the initial announcement frame TF 710 includes: the duration of the re-announcement frame 720 transmitted in response thereto + an SIFS and RU length (MU transmission time).

[0194] However, in some embodiments, the shared band can be allocated to the coordinated group for a duration corresponding to the “UL length” subfield 332 indicated in TF 710. In this case, none of the stations in the coordinated group will transmit after the UL length 332 period, thus freeing up the band for the coordinator device. This makes the final period of TXOP unused on the shared band: avoiding co-channel interference with AP1 BSS (primary 20MHz channel); furthermore, BA frame 241 can be copied by AP1 on the freed band to occupy the medium and reset any NAVs of nearby stations operating on that 20MHz channel.

[0195] Now go to Figure 8 and Figure 9 This describes the operation of various devices according to embodiments of the present invention.

[0196] Assume that all devices (specifically, AP and P2P group owners) have an AP candidate set, which lists other BSS or P2P groups that wish to have new resources provided for data transmission (through multi-AP sharing). Based on such a set and on resource requests from other APs and other P2P group owners, the coordinator device of the access medium can decide to share resources.

[0197] refer to Figure 8 In step 801, the coordinator device (e.g., the coordinator AP) prepares a trigger frame 710 to trigger multi-user (MU) transmissions of the coordinated scheme. TF 710 uses appropriate indications (e.g., the BSSID or DiL session identifier or MAC address in the corresponding AID12 subfield 341) to allocate some resource units to non-AP stations of its BSS, and to allocate one or more resource units to other BSSs and / or P2P groups.

[0198] During the same step 801, the coordinator AP also determines whether the coordinated device must send a re-announcement frame 702, and, where applicable, which coordinated devices must send a re-announcement frame 702.

[0199] As described above, the coordinator AP's decision can be included in dedicated re-announcement fields, such as one or more bits in trigger type subfield 331 (different values ​​correspond to different re-announcement schemes), bit B39 343, trigger-related user information subfield 344, common information subfield 330 (such as "CS required" bit 336 or bit B63 334), or even trigger-related common information field 335. The coordinator AP can, for example, instruct all coordinated devices to transmit re-announcement frame 720, or indicate that no coordinated device needs to do so, or indicate that only coordinated devices undergoing primary channel switching need to do so, or individually instruct each coordinated device that needs to do so (e.g., bit B39 343 for each shared RU).

[0200] The selection of RUs (Resource Units) allocated (shared) to coordinated devices can be made by the coordinator device taking into account whether the coordinated device must switch its primary channel. Preferably, the coordinator device seeks to reduce the number of coordinated devices (and therefore associated stations) that must switch their primary channels.

[0201] The coordinator device can know the primary channel used by each station (e.g., it may appear that a direct link session can occur outside the coordinator AP's BSS, making the primary channel of the direct link station different from the coordinator AP's primary channel) and / or the primary channel used by the coordinated BSS (e.g., it may appear that the coordinator BSS and the coordinated BSS do not have the same primary channel). In any case, the primary channel of the coordinated device is included in the channel bandwidth operated by the coordinator AP (otherwise the coordinated device would not receive the initial advertisement TF 710). As an example, the coordinator AP can use a BQR trigger frame (representing a bandwidth query report) to trigger the most appropriate channel for each coordinated device / BSS / P2P group.

[0202] As described above, in step 802, the PHY of the coordinator AP sends an initial announcement TF 710 prepared in this way to trigger various stations (some non-AP stations of the coordinator AP's own BSS, and coordinated devices such as other APs and / or P2P group owner stations in different BSSs). The initial announcement TF 710 is sent on each of the various 20MHz channels that form a common communication channel that is detected as idle.

[0203] The initial announcement TF 710 causes some of the coordinated devices to send a re-announcement frame 720. Therefore, in step 803a, the coordinator AP expects to receive such a control frame 720 (after TF 710) from the triggered coordinated device.

[0204] Optionally, the coordinator AP may also send the re-advertisement frame 720 simultaneously to one or more coordinated devices. This is step 803b. For example, this allows some devices that have difficulty or problems receiving the initial advertisement frame 710 to be reached, regardless of their BSS or group.

[0205] Next, in step 804, the coordinator AP participates in MU communication (230, 221, 241) on the resource units maintained for its BSS. If the RU is an uplink RU, the coordinator AP receives data frames from the non-AP STAs of its BSS.

[0206] Note that other transmissions occur in parallel on the shared frequency band that does not involve the coordinating AP. For each shared DiL RU, the destination non-AP STA (for direct link communication) receives data frames from the P2P group owner on that RU. For each shared RU assigned to a different BSS, MU transmissions occur within the different BSS (between non-AP STAs in that different BSS and the coordinated AP in the same BSS).

[0207] refer to Figure 9 In step 901, any non-coordinator device within the transmission range of the coordinator AP and one of the copies of the initial announcement TF 710 transmitted on the main channel receives the initial announcement TF 710. The non-coordinator device can be any non-AP STA of the BSS, an AP of the BSS, or a STA within a P2P group.

[0208] Note that regular trigger frames are handled in a conventional manner (e.g., 802.11ax) not shown in the flowchart.

[0209] The device can use information in the received frame to identify that the received frame is a resource sharing announcement frame 710.

[0210] For example, TF 710 may include a dedicated trigger type subfield 331 that identifies the notification frame, thereby inviting each receiving device to analyze each user information element therein to determine whether it is related to an upcoming MU transmission.

[0211] Alternatively, the device can analyze individual user information elements of the TF 710 to determine whether resources are shared with other BSS or P2P groups (e.g., whether the AID12 subfield includes a BSSID or P2P session identifier or MAC address).

[0212] Other means can be envisioned to allow analysis of received TFs. As an example, a device may have previously determined that its associated AP or group owner has notified other APs (coordinator device candidates) of its AP coordination capabilities by advertising a list of capabilities in management (e.g., beacon or probe response) frames transmitted by the AP or group owner.

[0213] In step 902, the non-coordinator device determines whether it is acting as a coordinated device. Essentially, this is the case when it is the group owner of an AP or P2P group whose shared resources are allocated to the BSS. In practice, the presence of its BSSID or MAC address in the AID12 subfield of a user information element (or any list of coordinated devices within the frame) is sufficient for the device to determine that it is a coordinated device.

[0214] If test 902 is positive, the coordinated device retrieves the re-announcement field (if present) from the received TF 710 in step 903. This is to determine (test 904) whether the coordinated device must transmit a re-announcement frame 720.

[0215] If test 904 is positive, the coordinated device creates a re-announcement frame 720 as described above, specifically by creating the re-announcement frame 720 by binary copying the MAC payload or its large data portion, in addition to preparing a MAC header with, for example, an empty TA field. The re-announcement frame 720 is then sent via SIFS following the initial TF 710. This transmission is performed simultaneously by all triggered coordinated devices in replication mode. This is step 905.

[0216] The next step is step 906, during which the device configures itself on the correct master channel.

[0217] As described above, if the original primary channel is contained within shared resources allocated to the device and its BSS or P2P group, the device does not need to modify its primary channel. Only the physical (PHY) layer is configured to operate the MU through one or more allocated shared resource units.

[0218] On the other hand, if the original primary channel is not included in the shared resources allocated to the device and its BSS or P2P group, the device must temporarily switch its primary channel at the PHY layer. If the allocated shared resources are greater than a single 20MHz channel, only one 20MHz channel becomes the primary channel, and the other channels are secondary channels.

[0219] If test 904 is negative, the process proceeds directly to step 906 to prepare the PHY layer.

[0220] Returning to test 902, if the result is negative, then the device is not a coordinated device.

[0221] During test 907, the device determined whether it was related to TXOP 200.

[0222] For non-AP stations of the coordinator AP, this means that these non-AP stations are assigned RUs (the AID12 subfield of the user information field includes their own AID).

[0223] For other devices in a BSS that are not part of the coordinator AP, they must determine whether shared resources have been allocated to their BSS or P2P group. This can be done by analyzing the RU's user information field 340 to detect identifiers (e.g., MAC address, DiL session identifier, BSSID) corresponding to their BSS or P2P group.

[0224] If the device is not related to TF 710, the process ends. Otherwise, the device waits to receive (step 908) a re-announcement to TF 720 (sent simultaneously by the triggered coordinated device, possibly including its local AP).

[0225] After step 908, the device prepares its PHY to the correct primary channel (step 906 above), and in particular, the device switches its primary channel (if necessary).

[0226] Note that devices outside the coordinator AP's transmission range do not receive TF 710 (step 901). However, due to the present invention, these devices associated with TXOP 200 (at least from their local AP or group owner) eventually receive the re-advertisement frame 720. For these out-of-range devices, the process begins directly at step 908 (dashed arrow on the right side of the figure). Due to the specific signal notification in TF 720, these devices are able to determine that the received frame is a re-advertisement frame and not the initial TF 710.

[0227] Once the device's PHY is ready (before the subsequent SIFS is re-announced to TF 720), they participate in MU transmission in their respective assigned RUs (which begin in the SIFS following TF 720) (step 909). At the end of TXOP 200, devices that have switched their primary channels switch back to their original primary channels.

[0228] Therefore, this invention enables out-of-range stations to eventually learn of resource sharing and thus temporarily switch their primary channels to actually participate in MU transmissions. The impact of this invention on the network is minimal (only the transmission time of the re-announcement TF 720 + SIFS). This is because, due to the binary copy of virtually all MAC payloads, various coordinated devices can quickly generate the same re-announcement frames and therefore send them simultaneously (rather than sequentially).

[0229] Although the above description is based on frequency division, the proposed mechanism based on successive announcement frames TF 710 and re-announcement frames TF720 can be applied in time division sharing (that is, various coordinated devices successively obtain their respective time slots for their BSS, and communication operates in single-user mode).

[0230] like Figure 3 As shown, the trigger frame format also includes an MCS subfield 345 in the user information field 340 corresponding to each RU. The MCS subfield indicates the modulation and coding scheme to be used. The coordinator device can specify different MCSs in the user information field 340 of the shared resources allocated to the coordinated devices (when preparing the frame in step 801). Based on this indication, the coordinated device can send a re-announcement frame 720 with different MCSs.

[0231] For example, a larger MCS can be indicated to reduce the overhead caused by re-announcement frame 720. The MCS value is preferably the same for all coordinated devices (so that the re-announcement frames sent by the coordinated devices are correctly superimposed on each other).

[0232] Figure 10 Another transmission sequence according to an embodiment of the present invention is shown.

[0233] In this scenario, AP1 reserves communication channels on three 20MHz channels. AP1 acts as the coordinator AP, meaning TF 710 is an advertisement frame for sharing resources (here, RU5 and RU6) with other BSSs or P2P groups. In this example, RU5 is assigned to BSS2 managed by AP2, while RU6 is assigned to STA. DiL1 The managed P2P group.

[0234] AP2 and STA DiL1 Upon receiving advertisement frame 710 and acting as coordinated devices, they subsequently (after SIFS) transmit the same re-advertisement frame 720 by repeating substantially all MAC payloads (simultaneously). In this figure, coordinator device AP1 also simultaneously transmits re-advertisement frame 720.

[0235] Upon receiving re-advertisement frame 720, all non-AP stations in BSS2 and the P2P group (including those outside AP1's transmission range) are now aware of resource sharing and can temporarily switch their primary channel (if needed). They are ready to transmit data during TXOP.

[0236] In this scenario, with Figure 7In contrast, the transmission sequence within BSS2 is modified: To avoid having a preamble 500 and associated data 510, the coordinated AP2 starts communicating in the shared RU using a DL transmission (DL MU PPDU - preamble 1000 and data RU 1010) that persists during the entire UL length 332 defined in the TF 710. In other words, the coordinated device starts multi-user downlink transmission with non-AP stations of its own basic service set over the allocated shared resources.

[0237] UL communication (UL PPDU preamble 1020 and UL data 1030) can occur after SIFS following the DL communication. This is intended to align the communication between BSSs (here BSS1 and BSS2), particularly the preambles. This reduces co-channel interference.

[0238] To correctly occur UL transmission without transmitting a trigger frame, a DL MU PPDU (1000, 1010) is used to trigger the uplink RU. In other words, the multi-user downlink transmission includes an indication of subsequent multi-user uplink transmission opportunities on the allocated shared resources.

[0239] For example, some DL data frames contain a TRS control subfield (According to 802.11ax, the TRS control subfield in the MAC header is used to initiate OFDMA transmission in the uplink direction, identify non-AP STAs participating in UL MU transmission, and allocate RUs to these STAs). The resulting UL RU 1030 provides space for the UL data and / or acknowledgments regarding the received DL data 1010 to be transmitted by the triggered (via TRS) non-AP stations of BSS2.

[0240] Generally, the TRS subfield within the MAC header of a data frame is used to trigger a response (UL transmission) from the same non-AP station that received the DL data frame. This means addressing the same non-AP STA in both DL and UL.

[0241] To bypass this limitation, the coordinated AP2 can consider using at least one DL RU in broadcast mode to send several MAC data frames to several non-AP stations respectively, each MAC data frame having a dedicated TRS subfield. Thus, allowing the DL broadcast RU to trigger several different UL RUs during the next UL transmission (with a notified duration 1099).

[0242] Note that the DL+UL communication sequence fits within the original duration 312 specified in the initial announcement frame TF 710: Duration of SIFS+TF 720+SIFS+UL length 332+SIFS+Duration 1099 < Duration 312 of TF 710.

[0243] In parallel, RU6 is shared for DiL transmissions. Preferably, DiL transmissions are aligned with MU transmissions in BSS1 and BSS2. To achieve this, the UL length field 332 of TF 710 is used to define the first DiL transmission (STA). DiL1 To STA DiL2 The duration of SIFS, and then a second DiL transfer (STA) can occur after SIFS. DiL2 To STA DiL1 It can continue until the end of TXOP (defined by the duration 312 of TF 710).

[0244] Although the present invention has been described above with reference to specific embodiments, the present invention is not limited to the specific embodiments, and modifications within the scope of the present invention will be apparent to those skilled in the art.

[0245] In particular, where appropriate, the different HE frame formats described in different embodiments can be replaced by EHT frame formats.

[0246] Many further modifications and variations will arise for those skilled in the art when referring to the foregoing illustrative embodiments. The foregoing illustrative 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.

[0247] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude multiple. 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 communication method in a wireless network, comprising performing the following steps at a wireless device operating on a main channel to communicate with one or more other wireless devices: A coordinator device that has been granted a transmission opportunity (TXOP) receives a frame for announcing that it shares the granted TXOP with the radio device. The announcement frame consists of a Medium Intervention Control (MAC) header and a MAC payload. The MAC payload includes resource allocation data content defining the resource allocation to the radio device. In response to receiving the notification frame, the system controls the switching of the operating primary channel to another primary channel corresponding to the shared resource, and sends a re-notification frame that repeats the resource allocation data content of the received notification frame, thereby driving one or more of the other wireless devices to switch their operating primary channel to the other primary channel.

2. The method of claim 1, wherein, The re-announcement frame has one or more start fields in the MAC header and MAC payload that are different from the announcement frame.

3. The method of claim 1, wherein, The re-announcement frame is also sent in response to determining, based on the received announcement frame, that the shared resources allocated to the wireless device do not include the primary channel of the wireless device.

4. The method of claim 1, wherein, The device also sends the re-announcement frame in response to a re-announcement field indicating that the received announcement frame must re-announce the resource share.

5. The method of claim 4, wherein, The re-announcement field indicates that the wireless device must re-announce resource sharing if it must switch its primary channel.

6. The method of claim 1, wherein, The wireless device is a management device for managing a group of wireless devices.

7. The method of claim 1, wherein, The re-announcement frame includes an empty transmitter address field (TA field) or does not include a TA field in its MAC header.

8. The method of claim 1, wherein, The wireless device is an access point (AP), which also sends trigger frames on the shared resources allocated to it to trigger multi-user uplink transmissions on the allocated shared resources to non-AP stations with its own basic service set.

9. The method of claim 1, wherein, The wireless device is an access point (AP), which also initiates multi-user downlink transmissions on allocated shared resources with non-AP stations using its own basic service set.

10. The method of claim 9, wherein, The multi-user downlink transmission includes an indication of subsequent multi-user uplink transmission opportunities on the allocated shared resources.

11. The method of claim 1, wherein, The wireless device also sends frames to announce the sharing of a portion of the shared resources allocated to the wireless device.

12. A communication method in a wireless network, comprising performing the following steps at a coordinator device: A frame is sent to grant a transmission opportunity (TXOP), the frame also announcing the sharing of the granted TXOP with one or more coordinated devices and including a re-announcement field indicating whether the one or more coordinated devices must re-announce resource sharing should one or more of them switch their primary channel for communicating with one or more other radio devices in connection with resource sharing. The announcement frame includes a Medium Access Control (MAC) header and a MAC payload, the MAC payload including resource allocation data content defining the resource allocation to the one or more coordinated devices; and A re-announcement frame is received from one or more coordinated devices to repeat the resource allocation data content of the sent announcement frame.

13. The method of claim 12, wherein, The re-announcement field is provided at the level of shared resources.

14. The method of claim 12, wherein, The coordinator device also simultaneously sends repeating re-announcement frames of the resource allocation data content to one or more of the coordinated devices.

15. A wireless communication device comprising at least one microprocessor configured to perform the steps of the method according to any one of claims 1 to 14.

16. A non-transitory computer-readable medium storing a program that, when executed by a microprocessor or computer system in a wireless device, causes the wireless device to perform the method according to any one of claims 1 to 14.

17. A computer program product comprising a program that, when executed by a microprocessor or computer system in a wireless device, causes the wireless device to perform the method according to any one of claims 1 to 14.

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