Method and apparatus for managing low-latency data transmission in a wireless network

Abstract

The present invention relates to a communication method in a wireless communication network, the method comprising: transmitting, in a station, a frame to an access point station comprising a buffer status report reporting an amount of buffered data to be transmitted; receiving from the access point station an allocation of resource units for the transmission of the buffered data; and transmitting the buffered data in the allocated resource units, the frame transmitted to the access point station further comprising an indication of a time representing a limit time for the transmission of the buffered data by the station.

Description

Technical Field

[0001] The present disclosure relates to managing low-latency transmission in a wireless network.

Background Art

[0002] Wireless communication networks must meet increasing bandwidth and decreasing latency requirements, especially in high-density environments. To address increasing bandwidth requirements, multi-user (MU) schemes have been developed. The MU scheme enables a single access point (AP) to schedule MU transmissions, i.e., multiple simultaneous transmissions to or from non-AP stations, in a wireless network. For example, one such MU scheme has been adopted by the IEEE in the 802.11ax-2021 standard.

[0003] Scheduling MU transmissions is based on the transmission requests (needs) declared by non-AP stations to the AP. Such declarations are typically made using a buffer status report (BSR). Using the BSR mechanism, a non-AP station reports to the AP the amount of data held in the transmit buffer that is ready to be transmitted to the AP, i.e., the amount of buffered uplink (UL) traffic. As a result, the BSR mechanism is adapted to report the amount of data held in the transmit buffer corresponding to a given traffic identifier (TID).

[0004] The information contained in the received BSR enables the AP to schedule MU UL transmissions. This scheduling involves selecting the non-AP stations to which MU UL transmissions are to be provided and determining the UL resource units to be allocated to each of the selected non-AP stations with respect to bandwidth and duration. Thus, each non-AP station having data to be transmitted is provided with wireless resources adapted for transmission.

[0005] This mechanism can ensure that a non-AP having data to transmit obtains an opportunity to proceed with the transmission of these data. The AP manages scheduling for efficient use of available wireless resources based on knowledge of the amount of data to be transmitted at each non-AP station. However, this scheduling is performed on a best-effort basis by the AP to provide the required transmission opportunity. This does not provide a guarantee for transmission delay, reliability, or jitter, which depends on the load of the wireless network. Summary of the Invention

[0006] The present invention has been devised to address one or more of the above concerns.

[0007] According to a first aspect of the present invention, a method of a communication method in a wireless communication network is provided. This method at a station includes transmitting a frame including a buffer status report reporting the amount of buffered data to be transmitted to an access point station; receiving, from the access point station, an allocation of resource units for transmission of the buffered data; transmitting the buffered data within the allocated resource units; and the frame transmitted to the access point station further includes an indication of time representing a time limit for the transmission of the buffered data by the station.

[0008] In one embodiment, the resource unit is a multi-user resource unit allocated within a transmission opportunity reserved by the access point station.

[0009] In one embodiment, the multi-user resource unit is an uplink resource unit for transmitting buffered data to the access point station.

[0010] In one embodiment, the multi-user resource unit is a direct link resource unit for locally transmitting buffered data.

[0011] In one embodiment, the buffered data is transmitted to a non-access point station associated with the access point station.

[0012] In one embodiment, the buffered data is transmitted to another access point station via multi-access point transmission.

[0013] In one embodiment, the frame including the buffer status report is transmitted within the same transmission opportunity including the allocated resource unit.

[0014] In one embodiment, the buffer status report includes an identifier indication for identifying the type of the buffered data, and a duration unit indication of the buffer status report for identifying the time unit used to represent the indication of the time.

[0015] In one embodiment, the identifier indication identifies the class of the buffered data.

[0016] In one embodiment, the identifier indication identifies the flow of the buffered data.

[0017] In one embodiment, the buffer status report includes an access category indication for identifying the access category corresponding to the buffered data, and a data unit indication for identifying the data unit used to represent the amount of the data.

[0018] ​​In one embodiment, the buffer status report is included in the quality of service or high throughput control field of an 802.11 MAC data frame.

[0019] According to another aspect of the present invention, there is provided a method of a communication method in a wireless communication network, the method comprising, at an access point station, receiving, in a frame transmitted by the station, a buffer status report reporting an amount of buffered data to be transmitted by the station; transmitting to the station an allocation of resource units for the transmission of the buffered data; comprising the frame transmitted by the station and comprising the buffer status report further comprises an indication of time, the resource unit is allocated based on the received indication of time.

[0020] In one embodiment, when the data amount is not zero, the indication of time represents a limited time for the transmission of the buffered data by the station, and the resource unit is allocated before the limited time.

[0021] In one embodiment, when the data amount is zero, the indication of time represents a limited time until the allocation of resource units is no longer required by the station.

[0022] According to another aspect of the present invention, there is provided a computer program product for a programmable device, the computer program product being loaded into a programmable device and, when executed by the programmable device, comprising a sequence of instructions for implementing the method according to the present invention.

[0023] According to another aspect of the present invention, there is provided a computer-readable storage medium storing instructions of a computer program for implementing the method according to the present invention.

[0024] According to another aspect of the present invention, a computer program is provided for causing a computer to execute the method of the present invention at runtime.

[0025] According to another aspect of the present invention, a station in a wireless communication network is provided, the station being a processor, transmitting a frame including a buffer status report reporting the amount of buffered data to be transmitted to an access point station, receiving an allocation of resource units for transmission of the buffered data from the access point station, and transmitting the buffered data within the allocated resource units, and comprising a processor configured as such, wherein the frame transmitted to the access point station further includes a time indication representing a time limit for the transmission of the buffered data by the station.

[0026] According to another aspect of the present invention, an access point station in a wireless communication network is provided, the access point station being a processor, receiving, in a frame transmitted by the station, a buffer status report reporting the amount of buffered data to be transmitted by the station, transmitting an allocation of resource units for the transmission of the buffered data to the station, and comprising a processor configured as such, wherein the frame transmitted by the station and including the buffer status report further includes an indication of time, and the resource units are allocated based on the received indication of time.

[0027] According to another aspect of the present invention, there is provided a frame designed to be transmitted by a station of a wireless communication network to an access point station, the frame comprising a buffer status report field reporting the amount of buffered data transmitted by the station, the frame further comprising a time indication field representing a limited time for the transmission of the buffered data by the station, or a limited time until the allocation of resource units is no longer required by the station.

[0028] In one embodiment, the time indication field is included in the buffer status report field.

[0029] In one embodiment, the time indication field is included in the frame and is different from the buffer status report field.

[0030] At least a part of the method according to the present invention can be implemented by a computer. Accordingly, the present invention can take the form of a completely hardware embodiment, a completely software embodiment (including firmware, resident software, microcode, etc.), or an embodiment combining a software aspect and a hardware aspect that can generally be referred to herein as a "circuit", "module", or "system". Further, the present invention can take the form of a computer program product embodied in any tangible expression medium having computer-usable program code embodied therein.

[0031] Since the present invention can be implemented in software, it can be implemented as computer-readable code for providing to a programmable device on any suitable carrier medium. The tangible non-transitory carrier medium may comprise a storage medium such as a floppy disk (registered trademark) disk, a CD-ROM, a hard disk drive, a magnetic tape device, or a solid state memory device. The transitory carrier medium may include electrical, electronic, optical, acoustic, magnetic, or electromagnetic signals, such as signals like microwaves or RF signals.

Brief Description of the Drawings

[0032] Next, embodiments of the present invention will be described by way of example only with reference to the following drawings.

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[0033] The techniques described herein can be used for various broadband wireless communication systems, including communication systems based on an orthogonal multiplexing scheme. Examples of such communication systems include a space division multiple access (SDMA) system, a time division multiple access (TDMA) system, an orthogonal frequency division multiple access (OFDMA) system, and a single carrier frequency division multiple access (SC-FDMA) system. An SDMA system can utilize sufficiently different directions to simultaneously transmit data belonging to a plurality of user terminals, i.e., wireless devices or stations. A TDMA system can enable a plurality of user terminals to share the same frequency channel by dividing a transmission signal into different time slots or resource units, with each time slot being assigned to a different user terminal. An OFDMA system utilizes orthogonal frequency division multiplexing (OFDM), which is a modulation scheme that divides the entire system bandwidth into a plurality of orthogonal subcarriers or resource units. These subcarriers may also be referred to as tones, bins, etc. In OFDM, each subcarrier can be independently modulated using data. An SC-FDMA system can transmit on subcarriers dispersed over the system bandwidth using interleaved FDMA (IFDMA), transmit on a block of adjacent subcarriers using localized FDMA (LFDMA), or transmit on a plurality of blocks of adjacent subcarriers using extended FDMA (EFDMA).

[0034] The teachings of this specification can be incorporated into various apparatuses (e.g., stations), such as being implemented within the apparatus or being executable by the apparatus. In some aspects, a wireless device or station implemented in accordance with the teachings of this specification may comprise an access point (so-called AP) or a non-access point (so-called non-AP station or STA).

[0035] Note that it is not excluded that an apparatus may operate as an AP of one wireless network and at the same time belong to another (adjacent) wireless network as a related STA. This can occur in the context of multi-AP technology that enables a certain degree of cooperation between adjacent APs for more efficient utilization of the limited available time, frequency, and space resources. Using such technology, two adjacent APs can share resources in terms of frequency or time, thus preventing interference. APs that cooperate to share resources are called cooperative APs. Further, data transmissions established by cooperative APs are called multi-AP transmissions.

[0036] The examples are described in the context of a WiFi (RTM) network, but the present invention can be used in any type of wireless network, such as a cellular network of a mobile phone that implements a very similar mechanism.

[0037] A low-latency (low latency) reliable service (LLRS) is a service provided to upper-layer traffic streams that prioritize and deliver MSDUs (data units of this traffic stream) within a worst-case delay budget having a given reliability / packet delivery ratio (PDR) and low jitter. Traffic that may be related to LLRS includes latency-sensitive data, i.e., data from applications such as games, media streaming, augmented reality, virtual reality, etc.

[0038] FIG. 1 shows an exemplary network environment 100 in which the present invention may be implemented to deliver LLRS traffic.

[0039] During the related procedure in which each communication station 101 - 107 assigns a specific related identifier (AID) to the requesting non - AP station, it registers with the central office or access point (AP) 110. For example, an AID that uniquely identifies a non - AP station, such as a 16 - bit value, can be used to identify the station in the exchanged frame. The AP 110 and the related non - AP stations 101 - 107 can represent a basic service set (BSS) or an extended service set (ESS).

[0040] When associated with a BSS, the communication stations 101 - 107, 110 exchange data frames under the control of the AP 110 via the wireless transmission channel 100 of the wireless local area network (WLAN). The wireless transmission channel 100 is defined by an operating frequency band composed of a single channel or multiple channels that constitute a composite channel.

[0041] Non - AP stations can also communicate directly via a direct wireless link (DiL), i.e., without the intervention of the AP relaying their messages. Exemplary situations of direct communication include the presence of peer - to - peer (P2P) transmissions between non - AP stations having the same primary channel.

[0042] Stations 101 - 107, 110 compete with each other using Extended Distributed Channel Access (EDCA) contention, are granted a Transmission Opportunity (TXOP), and then can obtain access to the wireless medium 100 to transmit (single-user (SU)) data frames. A station can also use a multi-user (MU) mode, in which a single station, typically the AP 110, is permitted to schedule MU transmissions, i.e., multiple simultaneous transmissions to or from other stations, during the TXOP granted in the wireless network. One such embodiment of the MU mode is adopted, for example, as multi-user uplink and downlink OFDMA (MU UL and DL OFDMA) procedures in the IEEE 802.11ax amendment standard. Thanks to the MU capabilities, non-AP stations have the opportunity to obtain access to the wireless medium via two access methods, namely, the MU mode and the conventional Extended Distributed Channel Access - EDCA (single-user) mode.

[0043] During MU DL transmission on an authorized communication channel, the AP performs multiple simultaneous basic transmissions to various non-AP stations via so-called Resource Units (RUs). As an example, a Resource Unit divides the communication channel of the wireless network in the frequency domain, for example, based on the Orthogonal Frequency Division Multiple Access (OFDMA) technique. The assignment of RUs to non-AP stations is signaled at the start of the MU downlink frame by providing the associated identifier (AID) of the non-AP station (individually obtained by each station during its association procedure with the AP) for each RU defined at the transmission opportunity.

[0044] During MU UL transmission, various non-AP stations can simultaneously transmit data to the AP via resource units that form a communication channel. To control MU UL transmission by non-AP stations, the AP previously transmits a control frame known as a trigger frame (TF). The trigger frame uses the associated identifier (Association IDentifier: AID) assigned to non-AP stations of the same BSS using a reserved AID that specifies the time of registration to the AP and / or a group of non-AP stations to allocate resource units to them. The TF also defines the start and length of MU UL transmission by non-AP stations.

[0045] A variant for triggering UL transmission depends on the use of a TRS (abbreviation for Trigger Response Scheduling) control subfield. Such a TRS control subfield is added to the DL data frame that the AP transmits to the non-AP station via the resource unit to provide resource unit allocation to the receiving non-AP station for subsequent MU UL transmission (MU DL transmission). Each TRS subfield allocates (and provides transmission parameters for) a single resource unit to the receiving non-AP station that receives the DL data frame.

[0046] Non-AP stations can represent various devices such as gaming clients, extended / virtual reality headsets, smartphones, wireless displays, and some of them, and must exchange (i.e., transmit and receive) low-latency or LLRS traffic over time. LLRS traffic has more restricted QoS requirements regarding, for example, PDR, jitter, and latency than non-LLRS traffic coexisting within the WLAN100.

[0047] The single-user (SU) mode of the 802.11 network protocol enables direct link (also called direct link (DiL), peer-to-peer (P2P) transmission) to be executed, and data (MAC) frames are addressed, for example, using the 48-bit IEEE MAC address of the destination station. Regarding the figure, two non-AP stations 103, 104 can also communicate directly via a direct wireless link (DiL for direct link), regardless of whether both non-AP stations belong to the same BSS or ESS. In a variant, direct communication between non-AP stations can be implemented without using an access point (known as ad hoc mode). For example, in the WiFi-Direct standard, devices can communicate directly via the 802.11 wireless medium without the need for an AP. Even when the number of P2P flows is usually not large, the amount of data per flow tends to be important, typically low-compression video, ranging from 1080p60 to 8K UHD resolution, and low latency can also be expected. In a variant, such P2P transmission is registered within the MU communication mode, i.e., under the coordination of an access point.

[0048] The following description mainly focuses on trigger frames for triggering UL transmission rather than the TRS control subfield. However, those skilled in the art can adapt the following teachings to the case of the TRS control subfield. Furthermore, the following teachings are also applicable to any communication traffic including P2P traffic.

[0049] The management of QoS (Quality of Service) is introduced at the station level in a wireless network via the EDCA mechanism defined in the IEEE 802.11e standard. The EDCA (Enhanced Distributed Channel Access) mechanism defines four traffic access categories (ACs) or "priorities" for managing media access: the voice access category (AC_VO), the video access category (AC_VI), both reserved for real-time applications (e.g., voice or video transmission), the best-effort access category (AC_BE) for standard applications, and the background access category (AC_BK) when traffic is light.

[0050] Four corresponding transmit buffers, or transmit / traffic queues or buffers are provided, and each AC has its own traffic queue / buffer to store the corresponding traffic as data frames such as MSDUs or A-MSDUs transmitted on the network. Data frames received from the upper layers of the protocol stack, i.e., MSDUs, are given 802.1D priorities or user priorities (UP) or traffic types (TIDs: representing traffic identifiers) that take values in the range of 0 to 7 respectively. Based on those TIDs, the MSDUs are mapped to one of the four AC queues / buffers to be stored in the mapped AC buffer using mapping rules. Of course, a different number of traffic queues may be contemplated.

[0051] Since the AP performs contention on behalf of non-AP stations in uplink OFDMA, it should be aware of both non-AP stations having uplink traffic (MSDUs) to be transmitted (in their buffers) and the amount of buffered UL traffic.

[0052] The 802.11 standard proposes that 802.11ax non-AP stations send a buffer status report (BSR) to the AP to report the buffered traffic.

[0053] As shown in FIG. 2, the BSR is included in the BSR control field provided in the MAC data frame.

[0054] The MAC data frame 200 includes a MAC header 210, a frame body 220, and an FCS field 230. The MAC header 210 includes, among other fields, a frame control header 211, a QoS control field 212, and an HT control field 213. The QoS control field 212 is in the original 802.11e format that can be used by non-AP stations of any 802.11 technology to report buffer status reports.

[0055] Alternatively, or optionally additionally, non-AP stations starting from the 802.11ax version (including further releases such as 802.11be / EHT) can do so using the HT control field 213.

[0056] It is recalled that 802.11 stations (APs and non-AP stations) maintain four access categories (ACs), thereby maintaining four corresponding transmission buffers (or transmit / traffic queues or buffers). Each AC has its own traffic queue / buffer for storing the corresponding data frames to be transmitted on the network. Data frames input from the upper layer of the protocol stack, i.e., MSDUs (MAC service data units), are mapped to one of the four AC queues / buffers and thus input to the mapped AC buffer. Thus, 802.11 stations support traffic prioritization similar to DiffServ (Differentiated Services), and the mapping is performed among one of the eight priorities of the traffic class of the incoming MSDU (TID values between 0 and 7 are considered user priorities and are identical to the IEEE 802.1D priority tags), which is a mapping to the corresponding one of the four ACs.

[0057] <802.11 Legacy BSR Format> As shown in the figure, the QoS control field 212 is composed of 2 bytes and contains the following information items: - Bits B0 to B3 are used to store the traffic identifier (TID) 204 that identifies the traffic stream. The traffic identifier takes the value of the transmission priority value (user priority (UP), a value between 0 and 7) corresponding to the data carried by the data frame, or takes the value of the traffic stream identifier (TSID) value for other data streams with values between 8 and 15; - Bit B4 is used by non-AP stations to distinguish the meaning of bits B8 to B15, which will be detailed below; - Bits B5 and B6 define the ACK policy subfield that specifies the acknowledgment response policy related to the data frame. This subfield is used to determine how the data frame must be positively acknowledged by the receiving station, i.e., to determine normal ACK, non-ACK, or block ACK. - Bit B7 is reserved and not used in the current 802.11 standard. - When bit B4 is set to 1, bits B8 to B15 represent the "queue size" subfield 203, indicating the amount of buffered traffic for a given TID in the non-AP station transmitting this frame. The queue size value is rounded up to the nearest multiple of 256 octets and is the total size of all packets buffered for the specified TID, represented in units of 256 octets. The access point can use this information to determine the next TXOP duration (duration) to grant to the station. A queue size of 0 indicates that there is no buffered traffic for that TID. A queue size of 255 indicates an unspecified or unknown size for that TID204. - Instead of using "Queue Size", when bit B4 is set to 0, bits B8~B15 represent the "TXOP Duration Requested" subfield. It indicates the duration in units of 32 μs that the transmitting station determines it needs for its next TXOP for the specified TID. Of course, "TXOP Duration Requested" takes into account all the packets buffered for the specified TID and thus provides a request equivalent to "Queue Size".

[0058] The following description is made using the "Queue Size" format of the buffer status report because this is its most common usage (the "TXOP Duration Requested" format is deprecated for MU usage). The 802.11e MAC frame format, more specifically the QoS control field 200, is retained for the promising standard version as described here.

[0059] The legacy BSR according to 802.11e can process one TID report per MSDU frame, which is one of the reasons why the extension was later provided by the 802.11ax version.

[0060] <802.11 ax BSR format> The HT-control field 213 can aggregate multiple control fields, resulting in a sequence of one or more control subfields 250. The length of the aggregated control field (A-control field) 213 is equal to 30 bits.

[0061] Each control subfield 250 includes a control ID 251 subfield that indicates the type of information carried in the subsequent control information subfield 252. Padding bits are added as necessary to reach 30 bits for the A-control field.

[0062] Accordingly, various types of information can be provided through the A-control field 213 according to the control ID 251. For example, the operation mode can be indicated in the control information sub-field 252 when the control ID 251 is 1. Also, the power data can be indicated in the control information sub-field 252 when the control ID 251 is 4.

[0063] When the control ID sub-field 251 is 3, the control information sub-field 252 of the control sub-field 250 includes buffer status information in the format of the BSR control field indicated by the reference number 260.

[0064] The non-AP station can report a buffer status report for the preferred AC or for all AC queues.

[0065] The buffer status information 260 is composed of five sub-fields, namely, the ACI bitmap 261, the delta TID 262, the ACI High 263, the scaling factor 264, the queue size High 265, and the queue size All 266.

[0066] Some N of the traffic identifiers for which there is buffered uplink UL traffic TID are signaled using the first two sub-fields in the BSR control field 260, namely, the ACI bitmap 261 and the delta TID 262.

[0067] The ACI bitmap sub-field 261 has 4 bits and indicates the access category for which the buffer status report is reported. Each bit of the ACI bitmap sub-field 261 is associated with one of the four ACs and is set to 1 to indicate that the buffer status report for the corresponding AC is included in the queue size All sub-field 266, and is set to 0 otherwise.

[0068] The exception is made for the specific case where the buffer status for all eight TIDs is included in the queue size All subfield 266. In that case, the ACI bitmap subfield = 0 is combined with the delta TID subfield 262 set to 3.

[0069] The delta TID subfield 262, together with the value of the ACI bitmap subfield, indicates the number of TIDs for which the non-AP station is reporting buffer status. The following table gives the relationship between these two subfields and the number of TIDs. This table is derived from Table 9-24d of the 802.11ax document, version 6.0. TIFF0007695372000001.tif109160The ACI High subfield 263 is used to indicate the ACI (Access Control Identifier) of the preferred AC for which the amount of buffered traffic is specified in the queue size High subfield 265.

[0070] The scaling factor subfield 264 indicates the unit SF of the queue size High and queue size All subfields 265, 266 in octets.

[0071] The queue size High subfield 265 indicates the amount of buffered traffic in SF octet units for the AC identified by the ACI High subfield 263, which targets the station (usually the AP) identified by the receiver address of the MAC frame 200.

[0072] The queue size All subfield 266 indicates the amount of buffered traffic in SF octet units for all ACs identified by the ACI bitmap subfield 261, which targets the station (usually the AP) identified by the receiver address of the MAC frame 200.

[0073] The queue size values set in the Queue Size High and Queue Size All subfields 265, 266 are the total size of all MSDUs and A-MSDUs buffered in the non-AP station reporting its buffer status, rounded up to the nearest multiple of the SF octet.

[0074] The standardized 802.11ax BSR remains dedicated to reporting buffer status from one (or more) of the four queues. This format no longer conforms to TID values greater than 7, although the legacy format still exists. For example, the upper layer may provide a data frame MSDU with an 802.1D user priority (UP) value taken from 8 to 15 values (known as TSID) reserved for low-latency delivery services.

[0075] Historically, IEEE 802.11e introduced the use of TSID along with a traffic specification (TSPEC) for a contention-free (non-competing) mechanism called HCCA (abbreviation for HCF Controlled Channel Access), which has been deprecated in 802.11ax. 802.11ax provided a centralized polling method by the AP for MU communication but remained lacking in handling actual QoS as required for low-latency services.

[0076] Since 802.11be aims to evaluate the ability to handle real-time (RT) traffic, using TSID is an easy traffic indication means for selecting an appropriate transmission operation mode. The Traffic Specification (TSPEC) could potentially be improved as a set of QoS parameters used to describe a TS (traffic stream) seen as a specific data flow between two stations.

[0077] The station can include the TSPEC in some action frames, such as ADDTS (Add Traffic Stream), to perform the admission request or closure of the characterized traffic.

[0078] When an access point obtains the traffic specification and / or buffer report for the set of stations of its BSS, the access point can specifically poll them through the scheduled resource unit allocation. This allocation is sent using a trigger frame for data transmission. Then, the stations having the allocated resource units transmit their buffered data within those allocated resource units (singular or plural). Since the MU UL / DL OFDMA transmission on all resource units of the composite channel should be time-aligned, if a station cannot send more data within the allocated resource unit, it can provide a padding payload. This can occur, for example, when no more data is buffered for transmission, or when the transmitting station does not desire to fragment the remaining data frames.

[0079] The access point can manage the resource unit size according to the reported needs. The access point can schedule uplink resource units to any of the stations that sent a report during the TXOP period.

[0080] For delay-sensitive and periodic UL traffic, the delay is not guaranteed, especially for varying traffic. This applies to any traffic that should be scheduled by the AP by the transmitter, such as P2P traffic (contrary to downlink OFDMA where the access point directly knows the amount and timing for sending multiple data to multiple stations).

[0081] Classical usage of 802.11 for constructing / using such reports is no longer compliant with low-latency transmission requirements because only global requirements are reported in the queue size information of those buffer reports or in the theoretical but unrealistic flow characteristic information delivered by the TSPEC. In any case, as will become apparent later in the present disclosure, the current formats of various reports in the art are not adapted to convey information regarding low-latency communication.

[0082] This misinforms the access point about the actual expected resources, and then it is misinformed about the allocation of resource units to 802.11 stations.

[0083] FIG. 3 is an explanatory diagram of this defect.

[0084] A low-latency high-reliability service (LLRS) is a service provided to upper-layer traffic streams that prioritizes and delivers MSDUs (data units) within the worst-case delay budget with a given reliability / packet delivery ratio (PDR) and low jitter.

[0085] From the perspective of meeting QoS constraints, several low-latency (LL) measurements have been studied to prioritize LLRS traffic within a BSS (basic service set). For example, specific LLRS resources such as frequency resources, time resources, or space resources can be allocated to LLRS traffic and thus can be used by non-AP stations that send or receive LLRS traffic.

[0086] In this scenario, the AP schedules a reserved service period 310. It can announce the start time and end time of each period. The reserved service period 310 can be completely dedicated to LLRS traffic exchange or, in a variant, can allow both LLRS traffic and non-LLRS traffic.

[0087] The reserved service period can preferentially be the Target Wake-up Time (TWT) service period (also called TWT SP, LL TWT SP, or restricted TWT SP). In other words, TWT operation is specialized to enable the AP to use an extended media access protection and resource reservation mechanism to provide a more predictable latency, reduced worst-case latency, and / or jitter for latency-sensitive traffic, which has higher reliability.

[0088] Using the target wake time, a device can determine when and how often to wake up to send and receive data. TWT enables the AP to manage activities within the network to minimize media contention between stations (STAs) and reduce the amount of time required for a power-saving STA to wake up. Thanks to this mechanism, a STA that requests a TWT can sleep except for the interval of the TWT service period (SP).

[0089] TWT SPs can be agreed upon individually or broadcast. Individual TWT SPs are negotiated between two individual stations (referred to as the TWT requesting STA and the TWT responding STA) and are specific times or sets of times at which the stations are expected to wake up to exchange frames with each other. During the negotiation, they send special information elements (TWT IEs) containing TWT parameters to each other, which can be interpreted as requests, proposals, demands, exchanges, acceptances, dictates, or rejections. Either the AP or a STA can tear down (destroy) the TWT by sending a TWT Teardown frame. Broadcast TWTs are similar to individual TWTs, except that a specific time or set of times is not negotiated between stations and is instead broadcast directly by the AP to multiple non-AP stations, for example using a beacon frame. In that case, the AP may use another mechanism based on the TIM element to indicate the set of STAs for which the AP is about to send (downlink data (DL)) or the set of STAs for which the AP is about to trigger uplink traffic. If a STA is not indicated in the TIM element, it means that it will not be requested within the next TWT SP.

[0090] T2, T5, T8 are the start times of LL SP310 announced by the AP.

[0091] T1, T3, T4, T6 are the arrival times of frames 371, 372, 373, 374 from the upper layer stack that are local to the non-AP station. Such frames are application frames consisting of a variable set of MSDUs (the size can vary). The timing of arrival is not very regular.

[0092] Sequences (330A - 340A - 350A) and (330B - 340B - 350B) show exemplary LL periods 310 in which the AP competes for media access prior to the LL SP. For illustration purposes, only communications where the transmitter is not the AP are shown (i.e., MU DL traffic is not represented).

[0093] When an access point obtains access to the wireless medium, the access point can specifically poll the associated TWT stations through the scheduled resource unit allocation. This allocation can be transmitted using trigger frame 330x (where x is A or B) for data transmission. Then, the stations having the allocated resource units send out their buffered data 340x within those allocated resource units. Since the MU UL / MU P2P OFDMA transmission on all resource units of the composite channel should be time-aligned, if a station cannot send more data within the allocated resource unit, it can provide a padding payload 341x.

[0094] Frame 371 can be fully transmitted within the MU UL RU 340A of the first LL SP 310.

[0095] Before the next TWT LL SP 310 scheduled at T5, it is waiting for some application frames to be transmitted (372 and 373). This unpredictable traffic cannot be fully processed within the MU UL RU of the second LL SP 310. This is the reason why the third frame 373 can only be partially transmitted.

[0096] When dealing with low-latency traffic (e.g., in the HMD scenario, the time domain, sufficient sampling rate, and low measurement latency and jitter are most important for human behavior and physiology), the aging of such frames can be relatively short. This means that LL frames that are typically mis-transmitted may be inappropriate for such applications due to their QoS constraints and may be re-transmitted later in vain. As a result, this also means that an LL frame that could not be delivered on time can be considered lost with respect to the chance of the next transmission.

[0097] Therefore, the remaining frame 373 is deleted at time T7 before the next TWT medium access T8.

[0098] This figure shows that RU is not exactly met (either too much padding or still unable to send LL data).

[0099] When real-time traffic is aperiodic and accompanied by unexpected arrivals, scheduling (as TWT) can be inefficient for many of the allocations that may not be used by the assigned STAs. Techniques such as TSPEC in the art are mainly based on assumptions of average rates, which are not live information and thus not adapted to traffic that is sensitive to aperiodic delays. Techniques such as the current BSR in the art only provide the amount of buffered traffic (status), which is unaware of the important timing requirements of live traffic.

[0100] In the case of delay-sensitive and periodic UL traffic, the delay is not guaranteed, especially for variable traffic.

[0101] The present invention aims to improve the use (scheduling) of radio resources for multi-user transmission, particularly for non-deterministic traffic (non-deterministic traffic can be variable traffic such as VBR or aperiodic traffic (when TSPEC is inconsistent), the traffic is based on the average data rate, and it is difficult to cope with the peak rate,...). This problem is particularly exacerbated when the traffic should follow low-latency or real-time requirements. To that end, an object of the present invention is to provide a more reliable data report from an 802.11 station to an 802.11 access point as a countermeasure to the problems raised.

[0102] The present invention provides a solution for a station to notify an AP of an actual immediate need for transmitting low-latency and variable traffic. The present invention relates to a method for providing a BSR in a frame transmitted to an AP, the BSR reporting the amount of data buffered at a STA for the AP to schedule resources, and the station further providing to the AP a limited time associated with the amount of data reported in the BSR for the STA to transmit data in the resources scheduled by the AP.

[0103] An exemplary wireless network for implementing embodiments of the present invention is one of an IEEE 802.11be network or a future version thereof. The present invention is particularly suitable for low-latency data transmission in IEEE 802.11be networks and future versions thereof and resource units.

[0104] Embodiments of the present invention generally apply to any station, non-AP or AP for which resources are to be scheduled by a scheduling station (e.g., an AP). The station (which may also be referred to as the scheduled station) may then provide information about its traffic requirements and timing constraints to the scheduling station according to embodiments of the present invention.

[0105] For example, in the case of a P2P link established between stations in a P2P group of stations, a coordinator station (e.g., a group owner) acting as a scheduling station for the P2P group must know the real-time information of other stations in the group.

[0106] Another example may relate to multi-AP transmission (as defined above). A first cooperative AP may be responsible for scheduling resources to be shared with a second cooperative AP. Here, the first AP may operate as a scheduling station and the second AP may operate as a scheduled station.

[0107] FIG. 4A schematically shows a communication device 400 that is either a non-AP station 101-107 or an access point 110 of a wireless network 100 configured to implement at least one embodiment of the present invention. The communication device 400 can preferably be a device such as a microcomputer, a workstation, or a lightweight portable device. The communication device 400 preferably comprises a communication bus 413 to which the following are connected: a central processing unit 401, such as a processor called a CPU, and a memory 403 for storing executable code of a method or method steps according to an embodiment of the present invention, similar to a register adapted to record variables and parameters necessary for implementing the method, at least one communication interface 402 connected via a transmission / reception antenna 404 to a wireless communication network, for example, a communication network according to one of the IEEE 802.11 standard family of standards, and includes.

[0108] Preferably, the communication bus provides communication and interconnectivity between various elements that are preferably included in or connected to the communication device 400. The representation of the bus is not limiting, and in particular, the central processing unit can operate to communicate commands directly to any element of the communication device 400 or via another element of the communication device 400.

[0109] The executable code can be stored in a memory that can be any of read-only, a hard disk, or a removable digital medium such as a disk. According to an optional variant, the executable code of the program can be received via the interface 402 by a communication network for storage in the memory of the communication device 400 before being executed.

[0110] In one embodiment, the device is a programmable device that uses software to implement embodiments of the present invention. However, alternatively, embodiments of the present invention may be implemented wholly or partially in hardware (e.g., in the form of an application specific integrated circuit or ASIC).

[0111] FIG. 4B is a block diagram schematically showing the architecture of a communication device 400 that is one of AP110 or stations 101 - 107 adapted to at least partially execute the present invention. As shown, device 400 includes a physical (PHY) layer block 423, a MAC layer block 422, and an application layer block 421.

[0112] The PHY layer block 423 (here typically a standardized 802.11 PHY layer) formats, modulates, or demodulates on any 20 MHz channel or composite channel, and thus has the task of transmitting and receiving frames via the wireless medium 100, such as an 802.11 frame or a media access trigger frame TF330. For example, it interacts with legacy 802.11 stations based on a 20 MHz width for transmission slots, MAC data, and management frames, and reserves OFDMA type MAC data frames with a legacy (typically 2 MHz or 5 MHz) smaller than 20 MHz width from / to its wireless medium.

[0113] The MAC layer block or controller 422 preferably includes an 802.11 MAC layer 424 that implements conventional 802.11ax / be MAC operations and an additional block 425 for at least partially executing embodiments of the present invention. The MAC layer block 422 may optionally be implemented in software loaded into RAM 403 and executed by CPU 401.

[0114] Preferably, an additional block 425, called a report management module, implements part of the embodiments of the present invention (from the perspective of the station or from the perspective of the AP). This block executes the operations of FIGS. 7 and / or 8 according to the role of the communication device 400.

[0115] For 802.11 MAC layer 424, the report management module 425 interacts to accurately handle communication via OFDMA RUs addressed to multiple stations according to embodiments of the present invention.

[0116] At the top of the figure, the application layer block 421 executes an application that generates and receives data packets, such as data packets of a video stream. The application layer block 421 represents all stacked layers above the MAC layer according to ISO standardization.

[0117] Next, as shown in FIG. 5, embodiments of the present invention are described by a new format report for low-latency traffic.

[0118] This format 500 is intended to be general and, as shown by FIG. 6A, can be rejected in a new independent format or a part of the format can be added to various existing types of reports, such as legacy buffer status as shown by FIG. 6C, 802.11ax buffer status as shown by FIG. 6B, or any combination thereof.

[0119] Preferably, at least a part of the report 500 is transmitted via the A-Control subfield 213. For example, when the control ID takes the value 7, it can be shown in the control information subfield 252, and the values from 8 to 15 remain reserved.

[0120] Report 500 is named as LL-BSR (Low Latency Buffer Status Report), and its use is indicated through a new entry 599 in the control ID table for the A-control field.

[0121] The purpose is to provide the STA with BSR indications (instructions) linked to the associated aging information, which can be regarded as the duration of the validity of the reported data volume. In other words, it includes the amount of data linked to the boundary timing, which brings an indication of the amount of data to be delivered under a given delay.

[0122] It should be noted that the indication of the boundary timing is different from any aging function indicated by the upper-layer application for MSDU discard in the MAC for operations such as the MSDU lifetime per TS. In fact, the MSDU lifetime per TS represents the average requirement of the traffic, and all MSDUs share the same expected delivery time. The timing indication is an indication of the time representing the limited time for the transmission of the buffered data reported in the LL-BSR.

[0123] Differently, the boundary delay of the LL-BSR is related to the instantaneous requirements of communication delivery at the MAC layer, information where the timing and amount of data vary according to past transmissions when the media attempt is lost, fluctuations in local receive buffer traffic, etc., and the expected next transmission (e.g., the next negotiated TWT service period).

[0124] Supplementary, the LL-BSR must be dynamic in the sense that (LL and non-LL) flows can be added or removed at any time without affecting the guarantees already given to other flows.

[0125] The LL-BSR 500 is composed of a traffic Id subfield 501, a data volume subfield 502, and a delay boundary 503.

[0126] The first field 501 identifies the traffic session for which the LL-BSR is issued. Depending on the low-latency service negotiated between the AP and the non-AP stations that generate reports, the traffic indication may appear to be able to support two forms of reporting: per-class reporting and per-flow reporting.

[0127] In per-class reporting, traffic flows with the same class share the same queue considered in the report: the AC value indicating the access category, the TID (alias user priority) indicating the type of traffic.

[0128] In per-flow reporting, specific upper-layer traffic is permitted as a resource reservation by the AP within its BSS, and the traffic flow identifier is used by the station to request its creation, modification, or deletion. As an example, the identifier can be a TSID indicating parameterized traffic, an SCSID by the stream classification service (SCS) of 802.11aa.

[0129] In other embodiments, since the identifier is for a low-latency traffic flow that continues during the TWT service period, it can be a TWT flow identifier.

[0130] When the LL-BSR is a report for P2P traffic, the AID of the receiving peer station can be used. Alternatively, a session identifier corresponding to the direct link session (e.g., the identifier of the established direct link) can be used for 501. This can be assumed when the AP permits a P2P session (such as the DLS protocol) and assigns an identifier for this session. In a preferred approach, the session identifier is located within the 12-bit AID format. Assigning a different value compared to the station's AID depends on the AP.

[0131] The data volume 502 is a count of the buffered data units related to the current buffer report.

[0132] The delay boundary is the current "live" information for the AP, which provides simplicity and efficiency for scheduling the next communication slot. It should be noted that neither the former EDCA nor the recent MU UL OFDMA can guarantee any throughput or delay boundary, but only guarantee performance differentiation between categories.

[0133] Thereby, the purpose of the LL-BSR is to propose a means for the transmitter STA to notify the scheduling station to achieve zero congestion loss.

[0134] Although the LL-BSR is described with respect to low-latency traffic flows, it is not limited to the application to one single traffic. Since stations can embed several multimedia traffics each having widely varying characteristics, stations can have different delay boundaries over time. Managing traffic individually is a burden. Therefore, the LL-BSR simplifies scheduling at the AP by notifying instantaneous and global needs (requirements) up to a boundary time (e.g., the use of a class-by-class report format, not flow-by-flow anymore, such class-by-class reports taking into account several flows). In a more extreme way, the use of such LL-BSR reports can also simplify TWT SP negotiation by not requiring detailed traffic specifications (e.g., only average data rate information can be used), and the scheduled stations can be periodically notified by the LL-BSR of the adapted requirements regarding the boundaries of the next service period(s).

[0135] It should be noted that the use of the LL-BSR format can be extended to algorithms specific to many implementations for network resource allocation.

[0136] FIG. 6A shows an embodiment of the LL-BSR 500.

[0137] LL-BSR also includes a traffic identifier subfield (601) and queue sizes (602) corresponding to subfields 501 and 502 respectively.

[0138] The ID subfield 601 identifies the traffic class (TID) or traffic stream (TSID, SCSID) to which the corresponding buffer status report belongs. As an example, this subfield can be 8 bits long.

[0139] Values 0 to 7 are set to identify user priorities for either TC or TS.

[0140] Values 8 to 15 are set to identify the TSID.

[0141] Values 16 to 31 are set to identify the SCSID (where the SCID value is determined by bit masking with 0xF).

[0142] Values 32 to 47 are set to identify the TWT flow identifier if the low-latency traffic flow continues during the TWT service period (where the TWT flow ID value is determined by bit masking with 0xF).

[0143] The BSR duration unit subfield (603A) indicates the unit of the regular BSR boundary duration subfield. The BSR duration unit subfield is set to 0 when the unit is 256 μs, set to 1 when the unit is a time unit (TU), and one TU corresponds to 1024 μs. Also, when the unit is represented as a multiple of the TBTT (the target beacon transmission time indicated in the BSS beacon frame), the value is set to 2. In other cases, it can be the value 3 represented with respect to the TWT wake-up interval negotiated between the TWT STA and the TWT AP. These examples are not limiting.

[0144] The regular BSR duration subfield (603B) indicates the maximum amount of time expected to elapse from the transmission of a frame containing a BSR until the next trigger frame, in units (units) indicated by the BSR duration unit subfield, to complete the transmission of the buffered data specified by the queue size subfield for the traffic identified by the STA.

[0145] Figure 6B presents an alternative embodiment based on BSR control by 802.11ax for LL-BSR.

[0146] The buffer status report reported in the LL-BSR control field consists of a high-priority AC, one queue size, and one delay boundary.

[0147] According to the 802.11ax standard, the ACI bitmap subfield 261 indicates the access category for which the buffer status report is reported, i.e., the queue size All 266.

[0148] An embodiment can include using the position of the queue size All subfield of the delay boundary subfield 613 instead of reporting the queue size All 266. The specific number of bits within the ACI bitmap subfield set to 0 can indicate the LL-BSR.

[0149] As a result, when the ACI bitmap subfield is 0 and the delta TID subfield is different from 3 (this value is already used in 802.11ax in this context where the ACI bitmap is set to 0), the buffer status report is the LL-BSR.

[0150] Preferably, the delta TID subfield is set to 0 since this value is not applicable to 802.11ax.

[0151] The following subfields are used for the LL-BSR report.

[0152] The ACI High subfield indicates the ACI of the AC for which the LL-BSR is indicated in the Queue Size High subfield.

[0153] Note that the Scaling Factor subfield indicates the unit SF of the Queue Size High subfield in octets.

[0154] The Queue Size High subfield indicates the buffered traffic volume of the AC identified by the ACI High subfield that intends the STA identified by the receiver address of the frame including the LL-BSR control subfield, in SF octet units.

[0155] The "Delay Boundary" subfield is 1 octet in length and indicates the delay boundary within the TU, truncated to the nearest TU, for the amount of buffered traffic to be sent as specified by the Queue Size High subfield. The STA identified by the receiver address of the frame including the LL-BSR control subfield (e.g., AP) is expected to schedule the buffered frames at the station that sends the LL-BSR for delivery within the time period specified by this Delay Boundary subfield.

[0156] Figure 6C presents an alternative embodiment based on QoS control for the LL-BSR.

[0157] The buffer status report reported in the QoS control field consists of the queue size values for a given TID.

[0158] The scheduled station according to the embodiment of the present invention can report the queue size for a given TID in the queue size subfield of the QoS control field in the QoS data or the QoS Null frame it transmits. The station can set B4 (LL-BSR indication bit 699) to 0 to indicate that the BSR is an LL-BSR, and the delay boundary information exists in the delay boundary subfield 503 of the LL-BSR control subfield 651. The bit unit size of the subfield 503 can be selected to an appropriate number.

[0159] In the case of a reported BSR with B4 set to 0, there is at most one LL-BSR subfield.

[0160] The STA can aggregate multiple QoS data frames or QoS Null frames in the A-MPDU and report the queue sizes and delay boundaries for different TIDs.

[0161] It can be understood that this illustration is non-limiting even if it is executed based on the legacy QoS control (212) followed by the control subfield 650 representing the delay boundary (503) that forms the LL-BSR according to the embodiment. For example, the same principle can be applied to the 802.11ax BSR format, and after a QoS frame having a control subfield 650 representing the BSR control field 260, a subsequent QoS frame embedding a control subfield 650 representing the delay boundary (503) can follow, which forms the LL-BSR together with the variant form.

[0162] The advantages of these embodiments (the alternative embodiments and the described variants of FIG. 6C) are to reuse the existing BSR format and / or code and ensure backward compatibility.

[0163] FIG. 7 shows an embodiment of the present invention implemented at the scheduled station 400 to generate a low-latency data report (LL-BSR) according to an embodiment of the present invention using a flowchart.

[0164] When the scheduled station allocates UL (and / or P2P) MU resources for low-latency data, it distributes a low-latency buffer status report (LL-BSR) to assist its scheduling station (e.g., AP). The scheduled station can implicitly distribute the LL-BSR in the LL-BSR control subfield of any frame transmitted to the AP (unsolicited LL-BSR), or explicitly distribute the LL-BSR in any frame transmitted to the AP in response to an LL-BSRP (LL-BSR polling) trigger frame (solicited LL-BSR).

[0165] The LL-BSRP trigger frame is a variant of a trigger having a new dedicated trigger type (e.g., a trigger type subfield with a value in the current range 8 - 15 not used by the 802.11ax standard).

[0166] An 802.11be / EHT station (AP and non-AP) according to an embodiment of the present invention can set the LL-BSR support subfield in the EHT capability element it transmits to 1, and otherwise, the station can set the LL-BSR support subfield to 0.

[0167] Note that an AP according to an embodiment of the present invention can transmit an LL-BSRP trigger frame including one or more RUs for random access.

[0168] The station reports its buffer status report (unsolicited LL-BSR) to the AP associated with it in QoS Null and QoS data frames, but also reports in response to an LL-BSRP trigger frame (solicited LL-BSR).

[0169] Step 700 has the requirement of sending LL-BSR (both solicited and unsolicited).

[0170] Test 701 consists of the station determining whether the recipient understands the LL-BSR. The result is always positive for the solicited LL-BSR. In the case of an unsolicited report, the STA can verify whether the AP indicates its support in the LL-BSR support subfield (information obtained in the relevant procedure) within its EHT capability element. If negative, in step 704, the process ends by transmitting a legacy BSR (not an LL-BSR).

[0171] Between steps 702 and 703, the station can determine whether the buffered data units are increasing within that buffer (both with respect to aging and quantity), and if no action is taken, it results in a data drop. Step 702 focuses on determining an appropriate interval for reporting for a given flow.

[0172] For example, regarding the low-latency delivery of real-time flows, the station may want to inform about the instantaneous buffer queue situation. The delay boundary can preferably be considered according to the negotiated service period of the flow related to the AP (the SP can be expressed in time units, TBTT, TWT wake-up interval, etc.). Any implementation-specific scheduling algorithm can be assumed, which is beyond the scope of the present invention.

[0173] Step 703 complements the previous step 702 by quantifying the buffered data with respect to the determined interval or delay boundary.

[0174] Note that a delay boundary set to a zero value can indicate the current buffer status equivalent to a legacy BSR. This can be used by the station when the traffic flow situation is normal.

[0175] The station may set the queue size subfield in the LL-BSR to a zero value if it indicates that no other scheduling is required during the period indicated by the delay boundary.

[0176] In other embodiments, the station may set the queue size subfield in the LL-BSR to a negative value to indicate that the average rate scheduled by the scheduling station needs to be reduced, for example, by reducing the amount of data provided for the periodicity indicated by the delay boundary. This is aimed at adapting the initial RU allocation through the first trigger frame of the service period.

[0177] Step 705 transmits the LL-BSR according to any format presented through FIGS. 5 and 6A - 6C.

[0178] As already explained, the station can aggregate several LL-BSRs (actually, one LL-BSR for each aggregated QoS_Null frame) to report for several flows. In that case, steps 701 - 702 - 703 are repeated accordingly for each flow to be reported.

[0179] FIG. 8 shows, using a flowchart, an embodiment of the present invention implemented at a scheduling station (AP) 400 when receiving a low latency data report (LL-BSR) according to an embodiment of the present invention.

[0180] The flowchart simply and non - limitatively shows one use, any further adaptation or a particular use of the received LL-BSR. The concept of the LL-BSR 500 is flexible enough for any implementation - specific scheduling algorithm.

[0181] For a given traffic flow, the AP receives an LL-BSR report from the station 400 (step 800). As already disclosed, the report may be per class or per flow, and may or may not be requested.

[0182] Since LL-BSR is self-contained, traffic identification is easy, and as a result, the AP can measure the remaining time until the next service period for the traffic under consideration. For example, a TWT scheduling AP uses the TWT flow identifier of the LL-BSR that identifies the existing TWT agreement to determine the next TWT SP start time for its TWT agreement.

[0183] As a result of the comparison between the shown delay boundary and any service period occurrence, test 801 proceeds to step 802.

[0184] The direct impact of the LL-BSR indication is applied to the next scheduled provisioning before the next SP. In a preferred embodiment further shown in FIG. 9, the RU allocation is performed in the same permitted TXOP as that used to receive the current LL-BSR.

[0185] The update of the next allocation is not limited to the examples provided. Any further medium allocation by the AP may be considered to meet the expectations of the station (e.g., a separate SU communication initiated by the AP, further MU scheduling when the AP does not have enough time to adapt the RU allocation for all stations of the current MU communication that each transmitted its own LL-BSR, etc.).

[0186] In step 803, the AP adapts its scheduling using the timing information associated with the BSR (advancing / retreating the scheduling and increasing / decreasing the resource size). For scheduling adaptation that requires changes upon the occurrence of a TWT SP, the AP can distribute a frame indicating an update to the TWT scheduling as a response to the frame for transmitting the LL-BSR. Otherwise, the scheduling of the TWT SP remains as it is, and the resource allocation within the SP is configured.

[0187] If the delay boundary has no meaning for the next service period (when test 801 is false), it can have meaning for long-term scheduling. An example can be an indication of delay based on the TBTT value (e.g., 10 times the value of the TWT SP).

[0188] As an example, a further test 804 can be performed to determine whether the station desires to notify a reduction in the average allocation. This can typically be the case when there is a negative queue size indication in the LL-BSR.

[0189] Therefore, the AP believes that this indication must be applied to the average rate specification of the traffic flow and accordingly adapts its scheduling accordingly (at least until further notified by another such LL-BSR of that type).

[0190] FIG. 9 provides an illustration of the advantages of the LL-BSR according to an embodiment of the present invention in the context of the timeline of FIG. 3.

[0191] Normally, the AP transmits the same TF during the service period starting at date T5.

[0192] The LL-BSR (identified as 900 in the figure) included in any MAC frame of the MU PPDU can be used by the AP to provide supplementary MU allocations within the same TXOP.

[0193] In the case of the first MU communication 340B, either MSDU Pi+2 or Pi+3 can include an LL-BSR in its MAC header. This is useful for indicating a subsequent MU communication 340C for this traffic flow of the same station. As is now apparent, MSDU Pi+3 can be fully transmitted through the second RU allocation provided by TF2.

[0194] Optionally, the LL-BSR is not included in Pi+2 or Pi+3, in which case Pi+3 is not transmitted within 340B and is replaced by a QoS_Null data frame containing the LL-BSR 900. This possibility offers the advantage of not fragmenting the Pi+3 frame.

[0195] As a result, the MSDU frame Pi+3 is delivered on time and is not lost as would occur with prior art means.

[0196] Note that the second MU communication triggered by TF2 may be shorter than the first MU communication triggered by TF1 based on the traffic specification. The number of trigger stations can also be different (typically fewer), and the allocation can span a larger RU for those stations.

[0197] Note that the use of the LL-BSR according to an embodiment of the present invention supports a more conservative allocation by the AP scheduler: the TSPEC specifies the minimum requirements for resources for a station that minimizes padding, and when the data peak is transmitted, the station notifies its delta data using a notification 900 that includes timing information and the required data volume.

[0198] The use of the LL-BSR according to the present invention aims to address the drawbacks of using TSPEC as the AP's native scheduling means. TSPEC does not provide real-time information but provides predictions, so the AP cannot maintain fine-tuning of its scheduling (TSPEC can only function as a maximum / minimum limit).

[0199] By adopting live reporting by the station 400 according to an embodiment of the present invention, resource unit allocation is more efficient for variable traffic. The allocation of wireless resources by the access point is performed with respect to the real needs of the scheduled stations for real-time traffic flows.

[0200] According to another aspect of the present invention, a method for updating the traffic specification of traffic permitted by a scheduling station (e.g., traffic of a station scheduled by an AP and associated with the AP) is provided. FIG. 10 shows an embodiment of the present invention according to this other aspect using a flowchart.

[0201] In this embodiment, the report 500 can be used. It can be named a Low Latency Buffer Status Report (LL-BSR), and its new use is indicated through a new entry 599 in the control ID table for the A-control field. For example, the value "8" can be used to indicate that it is used to modify the existing specification of traffic for which the new format has been identified.

[0202] Step 1000 is executed when such an LL-BSR for TSPEC update is received and determined to be of such a type.

[0203] Test 1001 is to determine whether the value of the data volume / queue size 502 is positive or negative for the identified traffic flow. Such determination can be performed by checking the MSB bit of the queue size field 502, where the MSB bit set to 1 indicates a negative value. In other words, the queue size field follows a signed notation such as two's complement representation (the first bit indicates the sign).

[0204] In the positive case (step 1002), the traffic specification is updated by a positive amount based on the data volume 502 and duration 503 specified by the BSR. Typically, the average data rate for the traffic specification of the identified traffic is increased by only the delta data rate calculated by averaging the data volume 502 over the duration 503.

[0205] Conversely, in the negative case (step 1003), the traffic specification is updated by a negative amount based on the data volume 502 and duration 503 specified by the BSR. Typically, the average data rate for the traffic specification of the identified traffic is decreased by only the delta data rate calculated by averaging the data volume 502 over the duration 503.

[0206] This adaptation of the traffic specification can be definitive until further notification by subsequent LL-BSR reception.

[0207] The use of LL-BSR according to this alternative embodiment of the present invention aims to address the drawback of using TSPEC as the AP's proprietary scheduling means. Since TSPEC does not provide real-time information but only predictions, the AP cannot maintain fine-tuning of its scheduling (TSPEC can only function as a maximum / minimum limit). The current alternative LL-BSR can seamlessly adapt the traffic specification (without specific management frames or renegotiation) by the AP's scheduling as a result.

[0208] Although the present invention has been described with reference to specific embodiments, the present invention is not limited to the specific embodiments, and modifications will be apparent to those skilled in the art within the scope of the present invention.

[0209] Many further modifications and variations are not intended to limit the scope of the present invention, which is determined only by the appended claims. By referring to the above exemplary embodiments, they will be suggested to those skilled in the art. In particular, different features from various embodiments can be exchanged as needed.

[0210] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that different features are recited in mutually different dependent claims does not indicate that a combination of these features cannot be used advantageously.

Claims

1. A communication method for a communication device that performs wireless communication, comprising: transmitting a frame including a buffer status report reporting the amount of buffered data to be transmitted to an access point device; receiving, from the access point device, an allocation of resource units for transmission of the buffered data; transmitting the buffered data using the allocated resource units; including when the communication device transmits the frame including a buffer status report for low-latency required data having a transmission limit time or a boundary timing at which transmission should be completed, the frame includes time information representing the transmission limit time or the boundary timing for the transmission of the low-latency required data; indicating that the buffer status report included in the frame is a buffer status report for low-latency required data having the transmission limit time or the boundary timing when the ACI bit map subfield included in the frame is set to 0 and the delta TID subfield included in the frame is set to a value different from 3.

2. A communication method for a communication device that performs wireless communication, comprising: transmitting a frame including a buffer status report reporting the amount of buffered data to be transmitted to an access point device; receiving, from the access point device, an allocation of resource units for transmission of the buffered data; transmitting the buffered data using the allocated resource units; including When the communication device transmits the frame including a buffer status report for low-latency required data having a limited time for transmission or a boundary timing at which transmission should be completed, the frame includes time information representing the limited time or the boundary timing for the transmission of the low-latency required data. The QoS control field of the frame has a subfield for setting a value indicating that the buffer status report included in the frame is a buffer status report for low-latency required data having the limited time or the boundary timing. Method. **Claim 3** The method according to claim 1 or 2, wherein the resource unit is a multi-user resource unit allocated to perform data transmission within a transmission opportunity reserved by the access point device. **Claim 4** The method according to claim 3, wherein the multi-user resource unit is an uplink resource unit for transmitting buffered data to the access point device. **Claim 5** The method according to claim 3, wherein the multi-user resource unit is a direct link resource unit for transmitting buffered data to another communication device. **Claim 6** The method according to any one of claims 1, 2, 3, or 5, wherein the buffered data is transmitted to a non-access point device associated with the access point device. **Claim 7** The method according to any one of claims 1, 2, or 3, wherein the buffered data is transmitted to another access point device via multi-access point transmission. **Claim 8** The method according to claim 1, wherein the buffer status report includes an identifier for identifying the type of the buffered data, Information for identifying the time unit used to represent the time information, and A method including

9. The method according to claim 8, wherein the identifier is information for identifying the class of the buffered data.

10. The method according to claim 8, wherein the identifier is information for identifying the flow of the buffered data.

11. The method according to claim 1, wherein the buffer status report Access category information for identifying the access category corresponding to the buffered data, and Data unit information for identifying the data unit used to represent the amount of the data, and A method including

12. The method according to claim 1 or 2, wherein the buffer status report is included in a service quality field or a high throughput control field of a MAC data frame compliant with the 802.11 standard series.

13. The method according to claim 1, wherein When the communication device transmits the frame including the buffer status report for the low-latency required data having the restricted time or the boundary timing, the frame further includes a queue size High subfield indicating an access control identifier of the access category of the low-latency required data, and a scaling coefficient subfield indicating a scaling coefficient unit of the queue size High subfield. A method

14. The method according to claim 2, wherein When the communication device transmits the frame including the buffer status report for the low-latency required data having the limit time or the boundary timing, and when the communication device does not transmit the frame including the buffer status report for data that is not the low-latency required data having the limit time or the boundary timing, different values are set in the control ID subfield included in the HT control field of the frame. Method.

15. The method according to claim 1 or 2, The communication device further receives the capability information of the access point device, When the capability information indicates that the access point device can understand the buffer status report including the time information, and when transmitting the low-latency required data having the limit time or the boundary timing, the communication device transmits the buffer status report including the time information to the access point device; when the capability information does not indicate that the access point device can understand the buffer status report including the time information, the communication device transmits the buffer status report not including the time information to the access point device. Method.

16. A communication method of an access point device in a wireless communication network, Receiving from the other communication device a frame including a buffer status report reporting the amount of buffered data to be transmitted by the other communication device; Transmitting to the other communication device an allocation of resource units for transmitting the buffered data; including When the other communication device transmits the frame including the buffer status report for the low-latency required data having a limit time for transmission or a boundary timing at which transmission should be completed, the frame including the buffer status report includes time information representing the limit time or the boundary timing for the transmission of the low-latency required data. When the ACI bitmap subfield included in the frame is set to 0 and the value set in the delta TID subfield included in the frame is different from 3, it indicates that the buffer status report included in the frame is a buffer status report for low-latency required data having the restricted time or the boundary timing, The method by which the resource unit is allocated based on the received time information.

17. A communication method of an access point device, Receiving, from the other communication device, a frame including a buffer status report reporting the amount of buffered data to be transmitted by the other communication device, Transmitting to the other communication device an allocation of a resource unit for transmission of the buffered data, including When the other communication device transmits a frame including a buffer status report for low-latency required data having a restricted time for transmission or a boundary timing at which transmission should be completed, the frame including the buffer status report includes time information representing the restricted time or the boundary timing for the transmission of the low-latency required data, The QoS control field of the frame has a subfield for setting a value indicating that the buffer status report included in the frame is a buffer status report for low-latency required data having the restricted time or the boundary timing, The method by which the resource unit is allocated based on the received time information.

18. The method according to claim 16 or 17, wherein when the amount of the data is not zero, the time information represents the limited time or the boundary timing for the transmission of the buffered data by the other communication device, and the resource unit is allocated to the other communication device to perform data transmission before the expiration of the limited time indicated by the time information or before the boundary timing.

19. The method according to claim 18, wherein when the amount of the data is zero, the time information represents the limited time or the boundary timing until the other communication device no longer needs the allocation of the resource unit.

20. A computer program for a programmable device, which, when loaded into the programmable device and executed by the programmable device, includes a series of instructions for implementing the method according to any one of claims 1 to 15.

21. A computer program for a programmable device, which, when loaded into the programmable device and executed by the programmable device, includes a series of instructions for implementing the method according to any one of claims 16 to 19.

22. A communication device for performing wireless communication, a transmission control unit for controlling to transmit a frame including a buffer status report reporting the amount of buffered data to be transmitted to an access point device; a reception control unit for controlling to receive an allocation of a resource unit for the transmission of the buffered data from the access point device; and having the transmission control unit controls to transmit the buffered data using the allocated resource unit. When the communication device transmits the frame including the buffer status report for low-latency required data having a limited time for transmission or a boundary timing at which transmission should be completed, the frame includes time information representing the limited time or the boundary timing for the transmission of the low-latency required data. When the ACI bit map subfield included in the frame is set to 0 and the value set in the delta TID subfield included in the frame is different from 3, it indicates that the buffer status report included in the frame is a buffer status report for low-latency required data having the limited time or the boundary timing. Communication device. Claim 23 A communication device that performs wireless communication, a transmission control unit that controls to transmit a frame including a buffer status report reporting the amount of buffered data to be transmitted to an access point device; a reception control unit that controls to receive an allocation of a resource unit for transmission of the buffered data from the access point device; having the transmission control unit controls to transmit the buffered data using the allocated resource unit, When the communication device transmits the frame including the buffer status report for low-latency required data having a limited time for transmission or a boundary timing at which transmission should be completed, the frame includes time information representing the limited time or the boundary timing for the transmission of the low-latency required data. The QoS control field of the frame has a subfield for setting a value indicating that the buffer status report included in the frame is a buffer status report for low-latency required data having the limited time or the boundary timing. Communication device. Claim 24 An access point device that performs wireless communication, A receiving unit that receives from the other communication device a frame including a buffer status report reporting the amount of buffered data to be transmitted by the other communication device, A transmitting unit that transmits to the other communication device an allocation of resource units for the transmission of the buffered data, and having When the other communication device transmits a frame including a buffer status report for low-latency required data having a transmission deadline or a boundary timing at which transmission should be completed, the frame including the buffer status report includes time information representing the transmission deadline or the boundary timing for the transmission of the low-latency required data, When the ACI bit map subfield included in the frame is set to 0 and the value set in the delta TID subfield included in the frame is different from 3, it indicates that the buffer status report included in the frame is a buffer status report for low-latency required data having the transmission deadline or the boundary timing, The resource unit is allocated based on the received time information, An access point device. **Claim 25** An access point device that performs wireless communication, A receiving unit that receives from the other communication device a frame including a buffer status report reporting the amount of buffered data to be transmitted by the other communication device, A transmitting unit that transmits to the other communication device an allocation of resource units for the transmission of the buffered data, and having When the other communication device transmits a frame including a buffer status report for low-latency required data having a transmission deadline or a boundary timing at which transmission should be completed, the frame including the buffer status report includes time information representing the transmission deadline or the boundary timing for the transmission of the low-latency required data, The QoS control field of the frame has a sub-field for setting a value indicating that the buffer status report included in the frame is a buffer status report for low-latency required data having the limit time or the boundary timing. The resource unit is an access point device allocated based on the received time information.

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