Signaling of IDC information through multi-sta ba frame in wireless LAN system

Abstract

The present disclosure relates to signaling of IDC information through a multi-STA BA frame in a wireless LAN system. According to an embodiment of the present disclosure, a method performed by a STA configured to operate in a wireless LAN system comprises the steps of: receiving a frame; and transmitting, in response to the frame, a multi-STA block acknowledgement (BA) frame including communication unavailability information related to the STA, wherein a BA information field of the multi-STA BA frame includes a per-association identifier (AID) traffic identifier (TID) information subfield related to the STA, and the communication unavailability information is included in the per-AID TID information subfield on the basis of an AID TID information subfield of the per-AID TID information subfield being set to a specific value.

Description

8 EDMG Compressed 9 Reserved 10 GLK-GCR 11 Multi-STA 12-15 Reserved

[201] In the present disclosure, reference to BlockAck frame without any other qualification applies to any of the variants, unless specific exclusions are called out.

[202] The GCR BlockAck frame is used in response to a GCR BlockAckReq frame, and the GLK-GCR BlockAck frame is used in response to a GLK-GCR BlockAckReq frame.

[203] An EDMG STA sets the No Memory Kept subfield to 1 to indicate that the free memory space indicated in the last RBUFCAP subfield might not be kept at the start of the next frame exchange sequence; otherwise, if set to 0, free memory space indicated by the RBUFCAP subfield is kept by the receiver for the next frame exchange sequence for the corresponding TID(s). The No Memory Kept subfield is reserved if transmitted by a STA that is not an EDMG STA.

[204] For an EDMG STA, the Memory Configuration Tag subfield indicates one out of two memory configurations as indicated in Memory Configuration Tag field in the recipient's EDMG Flow Control Extension Configuration element. For other types of STAs, this subfield is reserved.

[205] The Management Ack subfield is set to 1 to indicate that a frame of type Management and subtype that is not Action No Ack is acknowledged. This subfield is reserved if the BlockAck variant used is not the EDMG Multi-TID BlockAck variant.

[206] The meaning of the TID_INFO subfield of the BA Control field depends on the BlockAck frame variant type. The meaning of the BA Information field depends on the BlockAck frame variant type.

[207] Examples of BlockAck (frame) variants are described below. 1. Compressed BlockAck (frame) variant

[208] The TID_INFO subfield of the BA Control field of the Compressed BlockAck frame contains the TID for which this BlockAck frame is sent.

[209] The BA Information field of the Compressed BlockAck frame may have a format as shown in FIG. 16.

[210] FIG. 16 shows a format of the BA Information field of the Compressed BlockAck frame.

[211] Referring to FIG. 16, the BA Information field of the Compressed BlockAck frame may contain Block Ack Starting Sequence Control subfield and / or Block Ack bitmap subfield.

[212] The Block Ack Starting Sequence Control subfield may have a format as shown in FIG. 11. The Starting Sequence Number subfield of the Block Ack Starting Sequence Control subfield contains the sequence number of the first MSDU or A-MSDU for which this BlockAck frame is sent.

[213] The Fragment Number subfield of the Block Ack Starting Sequence Control field is set according to Fragment Number subfield encoding for the Compressed BlockAck variant shown in table 3 below:

[214] [Table 3] Fragment Number subfield Fragmentation level           3 (ON / OFF) Block Ack bitmap subfield length (octets) Maximum number      of MSDUs / A-MSDUs that can be acknowledged B3 B2-B1 B0 0 0 0 OFF 8 64 0 1 0 Reserved Reserved 0 2 0 32 256 0 3 0 Reserved Reserved 0 0 1 ON 8 16 0 1 1 Reserved Reserved 0 2 1 32 64 0 3 1 Reserved Reserved 1 Any Any Reserved Reserved

[215] A Compressed BlockAck frame with B0 of the Fragment Number subfield set to 1 is not sent to an HE STA whose Dynamic Fragmentation Support subfield in the HE Capabilities element it transmits is not set to 3. If B0 of the Fragment Number subfield is 0, the Block Ack Bitmap subfield of the BA Information field of the Compressed BlockAck frame indicates the receive status of up to 64 or 256 MSDUs and / or A-MSDUs depending upon the value of B2-B1 in the Fragment Number subfield as shown in table 3. Each bit that is equal to 1 in the compressed Block Ack Bitmap subfield acknowledges the reception of a single MSDU or A- MSDU in the order of sequence number, with the first bit of the Block Ack Bitmap subfield corresponding to the MSDU (or fragment thereof) or A-MSDU (or fragment thereof) with the sequence number that matches the Starting Sequence Number subfield of the Block Ack Starting Sequence Control subfield.

[216] If B0 of the Fragment Number subfield is 1, the Block Ack Bitmap subfield of the BA Information field of the Compressed BlockAck frame indicates the receive status of up to 16 or 64 MSDUs and / or A-MSDUs depending upon the value B2-B1 in the Fragment Number subfield as shown in table 3. If bit position n of the Block Ack Bitmap subfield is 1, it acknowledges receipt of an MPDU with sequence number value SN and fragment number value FN, where SSN is the value of the Starting Sequence Number subfield of the Starting Sequence Control subfield and the operations on the sequence numbers are performed modulo 4096. If bit position n of the Block Ack Bitmap subfield is 0, it indicates that the MPDU has not been received.

[217] If the B0 of the Fragment Number subfield is equal to 1, then the Block Ack Bitmap subfield is split into (Block Ack Bitmap subfield length) / 4 subbitmaps, each of which indicates receive status for 4 fragments of each of the MSDUs or A-MSDUs as indicated in table 3.

[218] 2. Multi-STA BlockAck (frame) variant

[219] The Multi-STA BlockAck frame is supported if either UL MU or multi-TID A-MPDU operation is supported and acknowledges MPDUs carried in an HE TB PPDU or multi-STA multi-TID, multi-STA single-TID, or single-STA multi-TID A-MPDUs.

[220] An HE AP that sends a Multi-STA BlockAck frame where the Per AID TID Info fields are addressed to more than one STA sets the RA field to the broadcast address. An HE AP that sends a Multi-STA BlockAck frame where the Per AID TID Info fields are all addressed to a single recipient STA and that is sent in response to an HE TB PPDU sets the RA field of the Multi-STA BlockAck frame to either the address of the recipient STA or to the broadcast address. An HE AP that sends a Multi-STA BlockAck frame where the Per AID TID Info fields are all addressed to a single recipient STA and that is not sent in response to an HE TB PPDU sets the RA field of the Multi-STA BlockAck frame to the address of the recipient STA.

[221] A non-AP HE STA sets the RA field to the TA field of the soliciting frame or to the address of the recipient STA whose Data or Management frames are acknowledged.

[222] The TID_INFO subfield of the BA Control field of the Multi-STA BlockAck frame is reserved.

[223] The BA Information field of the Multi-STA BlockAck frame may have a format as shown in FIG. 17.

[224] FIG. 17 shows a format of the BA Information field of the Multi-STA BlockAck frame.

[225] Referring to FIG. 17, the BA Information field of the Multi-STA BlockAck frame may comprise one or more Per AID TID Info subfields. The Per AID TID Info subfield may contain an AID TID Info subfield, and the AID TID Info subfield may have a format as shown in FIG. 18.

[226] FIG. 18 shows a format of the AID TID Info subfield.

[227] Referring to FIG. 18, the AID TID Info subfield may contain AID11 subfield, Ack type subfield, and / or TID subfield.

[228] The AID11 subfield carries the 11 LSBs of the AID of the non-AP STA for which the Per AID TID Info subfield is intended. The format of the Per AID TID Info subfield depends on the value of the AID11 subfield. If the Multi-STA BlockAck frame is sent to an AP, the AID11 subfield is set to 0. A value of 2045 in the AID11 subfield is used as an identifier for any unassociated STA. If the AID11 subfield is set to 2045, then the Ack Type subfield and TID subfield are set to 0 and 15, respectively.

[229] More than one Per AID TID Info subfield with the same value in the AID11 subfield but different values in the TID subfield can be present in the Multi-STA BlockAck frame.

[230] If the AID11 subfield of the AID TID Info subfield is not 2045, then the Per AID TID Info subfield may have a format as shown in FIG. 19.

[231] FIG. 19 shows a format of the Per AID TID Info subfield if the AID11 subfield is not 2045.

[232] Referring to FIG. 19, if the AID11 subfield is not 2045, the Per AID TID Info subfield of the Multi-STA BlockAck frame may contain AID TID Info subfield, Block Ack Starting Sequence Control subfield, and / or Block Ack bitmap subfield. The context and the presence of each optional subfield in a Per AID TID Info subfield in a Multi-STA BlockAck frame is shown in table 4:

[233] [Table 4] Ack Type subfied values TID subfield values Presence of Block Ack Starting Sequence Control   subfield   and Block   Ack   Bitmap Context of a Per AID TID Info subfield in a Multi- STA BlockAck frame subfields 0 0-7 Present Block acknowledgment context: Sent       as       an acknowledgment to QoS Data frames that solicit a BlockAck frame response  or to  a BlockAckReq frame 0 or 1 8-13 N / A Reserved 0 14 N / A Reserved 1 14 Not present All ack context: Sent       as       an acknowledgment to an A-MPDU that contains an MPDU that solicits an immediate response and all MPDUs contained in the A-MPDU are received successfully. 0 15 N / A Reserved 1 15 Not present Management / P S-Poll frame      acknowledgment context:

[234] As HE STAs do not use HCCA, TID values from 8 to 15 are not used in QoS data frames. If the Ack Type subfield is 0, the Fragment Number subfield encoding indicates the length of the BlockAck bitmap subfield as shown in table 5:

[235] [Table 5] Fragment Number subfield Fragmentat ion level 3 (ON / OFF) Block Ack   bitmap subfield length (octets) Maxim um number of MSDUs / A-MSDUs   that can        be acknowledged B 3 B2 -B1 B0 0 0 0 OFF 8 64 0 1 0 16 128 0 2 0 32 256 0 3 0 4 32 0 0 1 ON 8 16 0 1 1 16 32 0 2 1 32 64 0 3 1 4 8 1 A ny A ny Reserv ed Reserve d

[236] If B0 of the Fragment Number subfield of the Block Ack Starting Sequence Control subfield is 0, the BA Information field of the Multi-STA BlockAck frame contains an 8-octet, 16-octet, 32-octet, or 4-octet Block Ack Bitmap subfield depending on B2-B1 of the Fragment Number subfield as defined in table 5 indicating the receive status of up to 64, 128, 256, or 32 MSDUs (or fragments thereof) and / or A-MSDUs (or fragments thereof), respectively. Each bit that is equal to 1 in the Block Ack Bitmap subfield acknowledges the reception of a single MSDU (or fragment thereof) or A-MSDU (or fragment thereof) in the order of sequence number with the first bit of the Block Ack Bitmap subfield corresponding to the MSDU or A-MSDU with the sequence number that matches the value of the Starting Sequence Number subfield of the Block Ack Starting Sequence Control subfield. If B0 of the Fragment Number subfield of the Block Ack Starting Sequence Control subfield is 1, the Block Ack Bitmap subfield of the BA Information field of the Multi-STA BlockAck frame indicates the receive status of up to 16, 32, 64, or 8 MSDUs and / or A-MSDUs depending on B2-B1 of the Fragment Number subfield as shown in table 5. If bit position n of the Block Ack Bitmap subfield is 1, it acknowledges receipt of an MPDU with sequence number value SN and fragment number value FN with n = 4 x (SN - SSN) + FN, where SSN is the value of the Starting Sequence Number subfield of the Block Ack Starting Sequence Control subfield and the operations on the sequence numbers are performed modulo 4096. If bit position n of the Block Ack Bitmap subfield is 0, it indicates that the MPDU has not been received.

[237] If B0 of the Fragment Number subfield is 1, then the Block Ack Bitmap subfield is split into (Block Ack Bitmap subfield length) / 4 subbitmaps, each of which indicates receive status for 4 fragments of each of the MSDUs or A-MSDUs as indicated in table 5. For an A- MSDU, only the first bit of the subbitmap is used if fragmentation is not allowed in an A-MSDU.

[238] If the AID11 subfield of the AID TID Info subfield is 2045, then the Per AID TID Info subfield may have a format as shown in FIG. 20.

[239] FIG. 20 shows a format of the Per AID TID Info subfield if the AID11 subfield is 2045.

[240] Referring to FIG. 20, if the AID11 subfield is 2045, the Per AID TID Info subfield may contain AID TID Info subfield and / or RA subfield. The RA subfield indicates the MAC address of an unassociated STA for which the Per AID TID Info subfield is intended.

[241] An associated non-AP HE STA that receives a Multi-STA BlockAck frame as a response from its AP and does not support the UORA procedure ignores the 10 octets following the AID TID Info subfield that are the remainder of the Per AID TID Info subfield if the AID11 subfield is 2045 and parses the following Per AID TID Info subfields if any.

[242] Meanwhile, the current 802.11 Wi-Fi is being used together with non-Wi-Fi technologies (e.g., Bluetooth, ultra-wideband (UWB), Zigbee) in similar frequency bands (e.g., 2.4 / 5 / 6 GHz), and Wi-Fi and non-Wi-Fi technologies can operate together at the same time to operate multiple applications. This case may be referred to as in-device coexistence (IDC), and communication with each other may be affected by the IDC. Specifically, in the present disclosure, IDC may refer to an “unavailability” state in which a non-Wi-Fi technology temporarily or periodically occupies some or all of a channel on which a Wi-Fi STA operates, thereby interfering with transmission and reception of Wi-Fi packets and / or making it impossible to transmit and receive Wi-Fi packets. IDC is a type of unavailability state, and other unavailability states may exist in addition to IDC. In this disclosure, the terms “IDC” and “unavailability” may be used interchangeably.

[243] FIG. 21 shows an example of a situation in which an IDC occurs.

[244] Referring to FIG. 21, if IDC occurs temporarily at a time when a STA should receive data from an AP, the STA may not be able to receive the data. If the AP does not know that an IDC will occur in the STA, data loss may occur, and since the AP may continuously retransmit data to the STA through recovery, performance degradation may occur. In this case, if information about the IDC can be transmitted in advance, data loss can be prevented.

[245] Therefore, the present disclosure proposes a method for an STA (non-AP STA or AP) to transmit information about the IDC in advance and an apparatus implementing the method.

[246] In the present disclosure, “field”, “subfield”, and “element” may be used interchangeably.

[247] The specific notations (or, names) proposed in the present disclosure may be varied and are not limited thereto.

[248] FIG. 22 shows an example of a method performed by a STA for signaling of IDC information via a multi-STA BA frame according to an embodiment of the present disclosure.

[249] Referring to FIG. 22, in step S2201, the STA may receive a frame.

[250] In step S2203, the STA may transmit a multi-STA block acknowledgement (BA) frame comprising unavailability information related to the STA in response to the frame. BA information field of the multi-STA BA frame may comprise per association identifier (AID) traffic identifier (TID) information subfield related to the STA. The unavailability information may be included in the per AID TID information subfield based on an AID TID information subfield of the per AID TID information subfield being set to a specific value.

[251] According to various embodiments, the unavailability information may be included instead of a BA bitmap subfield in the per AID TID information subfield.

[252] According to various embodiments, the specific value of the AID TID information subfield may be determined based on at least one of a value of an AID 11 subfield in the AID TID information subfield, a value of an acknowledgement (Ack) type subfield in the AID TID information subfield, or a value of a TID subfield in the AID TID information subfield. For example, the value of the Ack type subfield may be 0, and the value of the TID subfield may be 13. Also, the value of the AID 11 subfield may not be 2045.

[253] According to various embodiments, a subfield comprising the unavailability information may be located after the AID TID information subfield in the per AID TID information subfield.

[254] According to various embodiments, the per AID TID information subfield may comprise a BA starting sequence control subfield. The BA starting sequence control subfield may be located after the AID TID information subfield in the per AID TID information subfield. The subfield comprising the unavailability information may be located after the BA starting sequence control subfield in the per AID TID information subfield.

[255] According to various embodiments, the per AID TID information subfield may comprise a BA starting sequence control subfield. The BA starting sequence control subfield may comprise a fragment number subfield. The fragment number subfield may inform a length of a subfield including the unavailability information.

[256] According to various embodiments, the unavailability information may comprise at least one of information for an unavailability start time or information for an unavailability duration. The unavailability start time may inform a value of timing synchronization function (TSF) at a time when the STA becomes unavailable. The unavailability duration may inform a duration in a specific time unit over which the STA is unavailable.

[257] According to various embodiments, a subfield comprising the unavailability information may be a feedback subfield. A subfield comprising the information for the unavailability duration may be located after a subfield comprising the information for the unavailability start time in the feedback subfield.

[258] According to various embodiments, the multi-STA BA frame may comprise information informing a presence of the unavailability information. A subfield comprising the information informing the presence of the unavailability information may be located before a subfield comprising the unavailability information in the multi-STA BA frame.

[259] According to various embodiments, the subfield comprising the information informing the presence of the unavailability information may be a feedback type subfield. The feedback type subfield may be included in a BA starting sequence control subfield in the per AID TID information subfield.

[260] According to various embodiments, the BA starting sequence control subfield may further comprise a fragment number subfield and a reserved subfield. The feedback type subfield may be located after the reserved subfield. The reserved subfield may be located after the fragment number subfield.

[261] According to various embodiments, a value 0 of the feedback type subfield may inform that the unavailability information related to in-device coexistence (IDC) is present.

[262] According to various embodiments, the information informing the presence of the unavailability information may comprise an identifier (ID) of the unavailability information.

[263] According to various embodiments, the received frame may comprise at least one of a buffer status report poll (BSRP) trigger frame or a quality of service (QoS) data frame.

[264] FIG. 23 shows an example of a method performed by an AP for signaling of IDC information via multi-STA BA frame according to an embodiment of the present disclosure.

[265] Referring to FIG. 23, in step S2301, the AP may transmit a frame to a STA.

[266] In step S2303, the AP may receive a multi-STA block acknowledgement (BA) frame comprising unavailability information related to the STA in response to the frame. BA information field of the multi-STA BA frame may comprise per association identifier (AID) traffic identifier (TID) information subfield related to the STA. The unavailability information may be included in the per AID TID information subfield based on an AID TID information subfield of the per AID TID information subfield being set to a specific value.

[267] Hereinafter, a detailed implementation of signaling of IDC information via multi-STA BA frames is described.

[268] Information about the IDC (referred to as IDC information in the disclosure) may include at least one of the following information elements:

[269] - IDC start time (or, unavailability (target) start time): Indicates when the IDC and / or “unavailability” occurs. For example, the IDC start time / unavailability (target) start time may indicate the value of timing synchronization function (TSF) [15:7] at the time when the STA becomes unavailable. The size of the IDC start time subfield may be 9 bits / 10 bits.

[270] For example, “unavailability” may mean that the STA is unavailable for the channel on which it operates, or for some subchannels (e.g., X 20MHz subchannels) in the channel. That is, “unavailability” may not mean that the STA is always unavailable for the channel on which it operates.

[271] For example, the entire (e.g., 8 octets) or a part (i.e., partial TSF) of the timestamp (TSF) received from the AP or the timestamp of the AP itself can be used for the IDC start time. For example, in the case of partial TSF, similar to the existing broadcast TWT, starting from a specific bit value of the TSF and up to X octets (e.g., 2 octets) of bit values can be used.

[272] For example, the IDC start time can be indicated using the period (e.g., in units of us) from the start time of transmission or the completion time of transmission of the frame in which the current IDC start information is transmitted.

[273] For example, the IDC start time can be indicated using the duration field of the MAC header. For example, the duration value of the duration field can be indicated to mean the period until the IDC start time. For example, if the IDC start time is indicated in the duration field, a separate indication can be omitted.

[274] - IDC duration (or, unavailability duration): The time / period during which the IDC lasts. The size of the IDC duration subfield can be 9 bits / 10 bits.

[275] For example, the IDC duration can be indicated in a specific unit (e.g., us).

[276] For example, information about the specific unit can be included. For example, unit information such as 1us, 8us, 32us, 64us can be included to indicate the unit for the duration value included thereafter. For example, if the duration value is 1000 and the unit is 1us, it can mean that the IDC duration is 1ms, and if the unit is 8us, it can mean that the IDC duration is 8ms. For example, the IDC duration / unavailability duration may indicate the duration in units of 64 us over which the STA is unavailable.

[277] For example, the IDC duration field can have 2 octets like the duration field of the MAC header, but is not limited thereto. For example, the IDC duration field can have a size smaller than 2 octets.

[278] - IDC Interval: If the IDC occurs periodically, it can mean the interval between consecutive IDCs. For example, the IDC interval may mean the interval between the start times of consecutive IDCs.

[279] For example, the IDC interval may be indicated in a specific unit (e.g., us).

[280] For example, information about the specific unit may be included. For example, unit information such as 1us, 8us, 32us, and 64us may be included to indicate the unit for the interval value included thereafter. For example, if the interval value is 1000 and the unit is 1us, it may mean that the IDC interval is 1ms, and if the unit is 8us, it may mean that the IDC interval is 8ms.

[281] For example, the IDC interval field may have 2 octets, like the duration field of the MAC header, but is not limited thereto. For example, the IDC interval field may have a size smaller than 2 octets.

[282] - IDC Continuity: It may mean information about how long the IDC continues.

[283] For example, the number of IDCs each of which continues (e.g., an integer) may be indicated.

[284] For example, the total duration from the IDC start time or the time point when the continuous IDC ends can be indicated. The duration and the time point can be indicated based on at least one of the IDC duration or the IDC start time described above, respectively.

[285] For example, the number of beacon frames, TBTT, and / or the beacon interval can be used. For example, the number of beacon frames, TBTT, and / or the beacon interval can be used to indicate how many times the beacon will be transmitted within the interval from the time when the IDC first occurs. As another example, the number of beacon intervals from the time when the IDC first occurs can be indicated in units of beacon intervals.

[286] For example, this IDC continuity subfield can be present when the IDC interval subfield is present.

[287] - IDC channel / bandwidth (BW): Channel / BW where IDC occurs.

[288] For example, IDC channel / BW can be indicated using a bitmap. For example, each bit in the bitmap can indicate whether each 20MHz subchannel is available in the operating channel / BW of the STA.

[289] For example, since each BW of the STA can be different, BW information can be additionally indicated. For example, when BW is indicated as 20MHz / 40MHz / 80MHz / 160MHz / 320MHz, the bitmap comprising bits of the number of 20MHz subchannels corresponding to each BW can be configured. For example, BW information may mean a limited BW that the STA can transmit / receive due to IDC, in which case the IDC channel may not be included.

[290] - IDC NSS(number of spatial streams) / antenna: It can indicate the available (or unavailable) NSS / antenna when IDC occurs.

[291] The IDC NSS value can mean the number of possible spatial streams. Using the IDC NSS value, the number of available (or unavailable) spatial streams due to IDC can be indicated, so that it is possible to use the actual available spatial streams.

[292] For example, the IDC NSS / antenna subfield can indicate the index of antennas that are available or unavailable in an IDC situation. For example, it can be possible to indicate antennas with low indexes to antennas with high indexes based on MSB or LSB by using a bitmap.

[293] The presence of information elements included in the IDC information can be determined depending on the IDC scenario. For example, if the IDC affects the primary channel of the BSS to which the STA belongs, the STA may not be able to use all channels due to the IDC, so the IDC channel may not exist. As another example, if the IDC occurs intermittently rather than periodically, the IDC interval and IDC continuity subfields may not exist. Therefore, at least one of the following methods may be used:

[294] 1) Utilization of Presence field

[295] A presence field may exist for each information element. For example, if the Presence field corresponding to a specific information is 1, a field for the corresponding information may exist. For example, the Presence field may be indicated in the form of a bitmap. Additionally, if the Presence bitmap exists, the remaining bits except for the number of fields corresponding to each information element may be reserved.

[296] FIG. 24 shows an example of an IDC information field including a Presence bitmap according to an embodiment of the present disclosure.

[297] Referring to FIG. 24, the Presence bitmap may indicate three information elements, and there may be an IDC start time and an IDC duration.

[298] 2) Fully Unavailability (e.g., 1 bit)

[299] For example, if the STA cannot transmit / receive on the operating channel due to the IDC, the fully unavailability may be indicated. For example, if the bit indicating the fully unavailability is set to 1 (i.e., in the case of fully unavailability), the IDC information may not include information / fields about the IDC channel.

[300] 3) Periodicity (e.g., 1 bit)

[301] If the IDC occurring in the STA occurs continuously with periodicity, the periodicity may be indicated. For example, if the bit indicating the periodicity is set to 0 (i.e., in the case of the IDC not having periodicity), the information / fields about the IDC interval and / or IDC continuity may not exist in the IDC information.

[302] FIG. 25 shows an example of an IDC information field including fields about fully unavailability and periodicity according to an embodiment of the present disclosure.

[303] Referring to FIG. 25, the value of the fully unavailability field may be set to 0 (i.e., not fully unavailability), and the value of the periodicity field may be set to 0 (i.e., the IDC does not have periodicity). If not fully unavailability, the IDC channel field may be present in the IDC information field. In addition, since the IDC does not have periodicity, the IDC interval field and the IDC continuity field may not be present in the IDC information field.

[304] FIG. 26 shows an example of an IDC information field including a length field according to an embodiment of the present disclosure.

[305] Referring to FIG. 26, the IDC information field may include a length field indicating the length of the IDC information field. The length field may allow a STA that cannot decode a new field added to the IDC information field to identify which field to ignore through the length field.

[306] In addition, an ID may be assigned to the IDC information field, and the IDC information field may include such an ID. This is for flexibly transmitting control information, and only when an ID for an IDC information field is indicated, the (control) information / field including the corresponding ID can be recognized as IDC information. When another ID is indicated, the control information of the corresponding ID, not the IDC information, can be identified. In the present disclosure, a field that can include an IDC information field can be referred to as a control information field.

[307] In some implementations, a generalized control information field can be configured. For this purpose, control information fields corresponding to one or more IDs can be included together / sequentially in a frame. For example, IDC information and other control information can be included together in a frame.

[308] In some implementations, a generalized control information field, such as in FIG. 27, can include a field for the number of control information fields (number of control info(s)).

[309] FIG. 27 shows an example of a generalized control information field including a field for the number of control information fields according to an embodiment of the present disclosure.

[310] Referring to FIG. 27, the number of control information fields is 2 (i.e., the value of the number of control information fields field is 2), the ID of the IDC information may be 0, and the ID of the BSR may be 1. Therefore, two control information fields (ID=0 IDC information field, ID=1 BSR field) may be included.

[311] In some implementations, a field for the number of control information fields may be omitted.

[312] In some implementations, a field for the number of control information fields may be configured in a form of an element including a length field.

[313] According to various embodiments of the present disclosure, the IDC information field (or the control information field / element including the IDC information) may be included in a multi-STA BlockAck (BA) frame. Since the multi-STA BA is a frame that can be transmitted to one or more STAs, it may include the IDC information field (or the control information field / element including the IDC information) based on at least one of the following methods (e.g., A, B).

[314] A. Utilizing specific values of AID TID Info fields of multi-STA BA frames

[315] In some implementations, the presence or absence of the IDC information field may be indicated by setting the value of the AID TID Info field of the Multi-STA BA frame to a currently unused AID TID Info field value. For example, at least one of the AID11, Ack type, and / or TID fields present in the AID TID Info field of the Multi-STA BA frame may be set to a specific value to set the currently unused AID TID Info field value. For example, the Ack type may be set to 0, and the TID may be set to one of the values 8 to 15.

[316] In some implementations, AID11 may be set to a specific value. For example, when a non-AP STA transmits a Multi-STA BA frame to the AP, AID11 may be set to a value other than 0 (e.g., 1, 2008). In such a case, the Ack type and TID may be set to any value. Since the non-AP STA transmits the Multi-STA BA frame only to the AP, the AP can identify the presence or absence of the IDC information field through the specific AID value.

[317] In some implementations, when the AP transmits the Multi-STA BA frame to one or more non-AP STAs, AID11 can be set to a specific value (e.g., one of 0, 2008~2044). When the AP transmits the Multi-STA BA frame to only one STA, AID11 can also be the AID of the corresponding STA.

[318] In some implementations, when a specific value of the AID TID Info field is used, the IDC information field (or the control information field / element including the IDC information) can be included instead of the Block Ack Starting Sequence Control field and / or the Block Ack Bitmap field in the Per AID TID Info field. The size of the field can be the size of the IDC information field (or the control information field / element including the IDC information) itself.

[319] FIG. 28 shows a first example of a structure of a Multi-STA BA frame including IDC information according to an embodiment of the present disclosure.

[320] Referring to FIG. 28, an IDC information field (or a control information field / element including IDC information) may be included in a Multi-STA BA frame by utilizing an AID TID Info field of the Multi-STA BA frame. A STA that has received data (e.g., multi-TID A-MPDU) from an AP may transmit a Multi-STA BA frame including IDC information related to information indicating that an IDC will occur. For example, at least one of AID11, an Ack type, or a TID may be set to a specific value (e.g., an Ack type may be set to 0, a TID may be set to 14), thereby indicating that an IDC information field (or a control information field / element including IDC information) is included thereafter. Meanwhile, BA information for one or more AID / TIDs (e.g., BA information for TID 1 and TID 2 for AP in FIG. 28) before the IDC information may also be transmitted together with the IDC information.

[321] In some implementations, the combined size of the Block Ack Starting Sequence Control field (2 octets) and the Block Ack Bitmap size (e.g., 4 octets, 8 octets) may be used for the IDC information field (or the control information field / element including the IDC information). For example, the size of the Block Ack Bitmap may be determined using a specific AID11 value, an Ack type = 0, a TID = any value and / or a fragment number subfield value, and the IDC information field (or the control information field / element including the IDC information) may be included using the Block Ack Starting Sequence Control field and / or the Block Ack Bitmap field. If the field size that can be utilized is larger than the field size of the IDC information field (or the control information field / element including the IDC information), the remaining bits except for the IDC information field (or the control information field / element including the IDC information) may be reserved. For example, when the fragment number subfield = {B3 = 0, B2-B1 = 3, B0 = 0}, the IDC information field (or the control information field / element including the IDC information) may be included by utilizing the block Ack bitmap size of 4 octets.

[322] FIG. 29 shows a second example of a structure of a Multi-STA BA frame including IDC information according to an embodiment of the present disclosure.

[323] Referring to FIG. 29, the IDC information field (or the control information field / element including the IDC information) may be included in the Multi-STA BA frame by utilizing the AID TID Info field of the Multi-STA BA frame. A STA that receives data (e.g., multi-TID A-MPDU) from an AP may transmit a multi-STA BA frame that includes IDC information related to information indicating that an IDC will occur. For example, the presence of a Block Ack Starting Sequence Control field (e.g., 2 octets) may be determined by setting at least one of the Ack Type or TID to a specific value (e.g., both the Ack Type and TID are set to 0), and the size of the Block Ack Bitmap (e.g., 4 octets) may be determined by setting the Fragment Number field to {B3 = 0, B2-B1 = 3, B0 = 0}. Accordingly, the Ack Type, TID, and / or Fragment Number fields may be utilized to include an IDC information field (or a control information field / element including the IDC information) instead of the existing information (e.g., a Block Ack Bitmap subfield).

[324] In some implementations, the AID11 subfield set to a specific value may be used to indicate whether the IDC information field (or a control information field / element including the IDC information) is included. For example, by utilizing AID11, Ack type, TID, and / or fragment number fields, an IDC information field (or a control information field / element including IDC information) may be included instead of existing information (e.g., Block Ack bitmap subfield).

[325] In some implementations, the IDC information field (or a control information field / element including IDC information) may be included, and the remaining bits other than the IDC information field (or a control information field / element including IDC information) may be reserved.

[326] By indicating the size of the block Ack bitmap (or the IDC information field (or the control information field / element including IDC information)), a STA that cannot decode the presence of IDC information when a Multi-STA BA frame is transmitted to multiple STAs may be able to identify the length of each AID TID Info field. Meanwhile, BA information for one or more AIDs / TIDs (e.g., BA information for TID 1 and TID 2 for the AP in FIG. 29) before the IDC information may also be transmitted.

[327] FIG. 30 shows an example of a format of a Per AID TID Info subfield including IDC / unavailability information according to an embodiment of the present disclosure.

[328] Referring to FIG. 30, for example, if the value of the AID11 subfield in the AID TID Info subfield is a value other than 2045, the value of the Ack type subfield is 0, and / or the value of the TID subfield is 13, the Per AID TID Info subfield may include a corresponding AID TID Info subfield, a Block Ack Starting Sequence Control subfield, and a feedback subfield. That is, compared to FIG. 19, the Per AID TID Info subfield may include a feedback subfield instead of a Block Ack bitmap subfield. The feedback subfield may be a subfield including feedback information such as IDC / unavailability information (e.g., an IDC information field (or a control information field / element including IDC / unavailability information)). An example of a format of the Block Ack Starting Sequence Control subfield is described in FIG. 31. An example of the format of the feedback subfield is described in FIG. 32.

[329] FIG. 31 shows an example of a format of the Block Ack Starting Sequence Control subfield when IDC / unavailability information is included according to an embodiment of the present disclosure.

[330] Referring to FIG. 31, when IDC / unavailability information is included (e.g., when the value of the AID11 subfield in the AID TID Info subfield is a value other than 2045, the value of the Ack type subfield is 0, and / or the value of the TID subfield is 13), the Block Ack Starting Sequence Control subfield may include a fragment number subfield, a reserved subfield, and a feedback type subfield.

[331] The fragment number subfield may indicate the length of the feedback subfield according to the fragment number subfield encoding in table 5.

[332] The feedback type subfield may include information for identifying the IDC / unavailability information (e.g., an ID of the IDC / unavailability information). For example, if the value of the feedback type subfield is 0, it may indicate that IDC / unavailability information is included. In other words, the feedback type subfield whose value is set to 0 may be related to information for identifying the IDC / unavailability information (e.g., an ID of the IDC / unavailability information).

[333] FIG. 32 shows an example of a format of a feedback subfield according to an embodiment of the present disclosure.

[334] Referring to FIG. 32, the feedback subfield may be a subfield including feedback information such as IDC / unavailability information (e.g., an IDC information field (or, a control information field / element including the IDC / unavailability information)). For example, the feedback subfield may include an IDC start time / unavailability (target) start time subfield, an IDC duration / unavailability duration subfield, and a reserved subfield.

[335] The IDC start time / unavailability (target) start time subfield may indicate the value of timing synchronization function (TSF) [15:7] at the time when the STA becomes unavailable. The size of the IDC start time subfield can be 9 bits / 10 bits.

[336] The IDC duration / unavailability duration subfield may indicate the duration in specific units (e.g., in units of 64 us) over which the STA is unavailable. The size of the IDC duration / unavailability duration subfield can be 9 bits / 10 bits.

[337] B. Utilizing a specific value of the Fragment Number field of the Block Ack Starting Sequence Control field of the Multi-STA BA frame

[338] In some implementations, the presence of the IDC information can be indicated by setting a specific value of the Fragment Number field of the Block Ack Starting Sequence Control field of the Per AID TID Info field.

[339] For example, a specific value of the Fragment Number field that is not used in the Fragment Number field (e.g., indicating a reserved value for the Block Ack bitmap) can be used (e.g., B3 = 1, B2-B1 = 3, B0 = 1).

[340] If a specific value of the fragment number field is used, the IDC information field (or the control information field / element containing the IDC information) may be included instead of the Block Ack bitmap subfield. For example, the size of the field may be the size of the IDC information field (or the control information field / element containing the IDC information) itself. For example, the size of the Block Ack bitmap subfield may be used as the size of the IDC information field (or the control information field / element containing the IDC information). For example, if 4 octets are used, the remaining bits except for the bits used for the IDC information field (or the control information field / element containing the IDC information) may be reserved.

[341] In some implementations, method B may be used together with method A.

[342] FIG. 33 shows a third example of a structure of a Multi-STA BA frame including IDC information according to an embodiment of the present disclosure.

[343] Referring to FIG. 33, whether an IDC information field (or a control information field / element including IDC information) is included can be indicated by utilizing a specific value of a Fragment Number field in BA information of a Multi-STA BA frame. For example, the Fragment Number field can be set to 1111 (i.e., B3 = 1, B2-B1 = 3, B0 = 1), indicating that an IDC information field (or a control information field / element including IDC information) is included thereafter. This method can indicate whether there is IDC information when a multi-STA BA frame is transmitted to a STA. Meanwhile, BA information for one or more AIDs / TIDs (e.g., BA information for TID 1 and TID 2 for an AP in FIG. 33) before the IDC information can also be transmitted.

[344] In some implementations, the presence of the IDC information field can be indicated using at least one bit of the bits of the reserved field, through which the receiving STA can identify in advance that the IDC information is present or absent.

[345] In some implementations, the presence of the IDC information field (or the control information field / element including the IDC information) can be indicated using an ID as in FIG. 26 and FIG. 27. In this case, if the presence of the IDC information field (or the control information field / element including the IDC information) is indicated and the IDC information field (or the control information field / element including the IDC information) exists, the receiving STA can identify that the IDC information field (or the control information field / element including the IDC information) is included based on a specific ID mapped to the IDC information.

[346] In some implementations, at least one of the No Memory Kept subfield, the Memory Configuration Tag subfield, or the Management Ack subfield, which is not used by non-DMG STAs, may be replaced with a presence field for the IDC information field (or the control information field / element containing the IDC information).

[347] In some implementations, a specific value (e.g., 0, 2) of the TID_INFO subfield may be used instead of a bit in the reserved field to indicate the presence of the IDC information field (or the control information field / element containing the IDC information).

[348] In some implementations, the IDC information field (or the control information field / element containing the IDC information) may be located next to (or after) the BA information field, if present.

[349] In some implementations, the BA information field may not be included when the IDC information field and / or the control information field (containing the IDC information field) are included. In such a case, whether or not to additionally include the BA information field may be indicated based on at least one of the above-described methods.

[350] In various embodiments, the Multi-STA BA frame may be a response to a data frame.

[351] In various embodiments, the Multi-STA BA frame may be a response to a frame other than a data frame.

[352] FIG. 34 shows an example of transmitting a Multi-STA BA frame including IDC information as a response to a frame according to an embodiment of the present disclosure.

[353] Referring to FIG. 34, a Multi-STA BA frame including an IDC information field (or a control information field / element including IDC information) may be transmitted as a response to a BlockAckReq (BAR) frame (e.g., a Multi-TID BAR), a basic TF, a BSRP TF, a BQRP TF, or another frame variant.

[354] The technical features of the present disclosure described above can be applied to various devices and methods. For example, the technical features of the present disclosure described above can be performed / supported by the devices of FIG. 1 and / or FIG. 5. For example, the technical features of the present disclosure described above can be applied only to a part of FIG. 1 and / or FIG. 5. For example, the technical features of the present disclosure described above can be implemented based on the processing chips 114, 124 of FIG. 1, or implemented based on the processors 111, 121 and the memories 112, 122 of FIG. 1, or implemented based on the processor 510 and the memory 520 of FIG. 5.

[355] For example, the processor 121 and / or the processing chip 124 of FIG. 1 can be configured to execute instructions stored in the memory 122 to perform operations performed by the STA in the present disclosure. The operations comprise: receiving a frame; and transmitting a multi-STA block acknowledgement (BA) frame comprising unavailability information related to the STA in response to the frame, wherein BA information field of the multi-STA BA frame comprises per association identifier (AID) traffic identifier (TID) information subfield related to the STA, and wherein the unavailability information is included in the per AID TID information subfield based on an AID TID information subfield of the per AID TID information subfield being set to a specific value.

[356] For example, the processor 111 of FIG. 1, the processing chip 114 and / or the processor 510 of FIG. 5 may be configured to execute instructions stored in the memories 112, 520 to perform operations performed by the AP in the present disclosure. The operations comprise: transmitting a frame to a station (STA); and receiving a multi-STA block acknowledgement (BA) frame comprising unavailability information related to the STA in response to the frame, wherein BA information field of the multi-STA BA frame comprises per association identifier (AID) traffic identifier (TID) information subfield related to the STA, and wherein the unavailability information is included in the per AID TID information subfield based on an AID TID information subfield of the per AID TID information subfield being set to a specific value.

[357] The technical features of the present disclosure can be implemented based on a computer readable medium (CRM) (e.g., non-transitory CRM). For example, the CRM in the present disclosure may comprise at least one CRM having stored thereon a program code implementing instructions executed by at least one processor.

[358] For example, the CRM may be the memory (122) of FIG. 1 and / or a separate external memory / storage medium / disk. The CRM may have stored thereon one or more program codes implementing instructions that, based on being executed by the processor (e.g., the processor 121 and / or the processing chip 124 of FIG. 1), perform operations performed by the STA in the present disclosure. The operations comprise: receiving a frame; and transmitting a multi-STA block acknowledgement (BA) frame comprising unavailability information related to the STA in response to the frame, wherein BA information field of the multi-STA BA frame comprises per association identifier (AID) traffic identifier (TID) information subfield related to the STA, and wherein the unavailability information is included in the per AID TID information subfield based on an AID TID information subfield of the per AID TID information subfield being set to a specific value.

[359] For example, the CRM may be the memory 112 of FIG. 1, the memory 520 of FIG. 5, and / or a separate external memory / storage medium / disk. The above CRM may have stored thereon one or more program codes implementing instructions that, based on being executed by a processor (e.g., the processor 111 of FIG. 1, the processing chip 114 and / or the processor 510 of FIG. 5), perform operations performed by the AP in the present disclosure. The operations comprise: transmitting a frame to a station (STA); and receiving a multi-STA block acknowledgement (BA) frame comprising unavailability information related to the STA in response to the frame, wherein BA information field of the multi-STA BA frame comprises per association identifier (AID) traffic identifier (TID) information subfield related to the STA, and wherein the unavailability information is included in the per AID TID information subfield based on an AID TID information subfield of the per AID TID information subfield being set to a specific value.

[360] The foregoing technical features of this disclosure are applicable to various applications or business models. For example, the foregoing technical features may be applied for wireless communication of a device supporting artificial intelligence (AI).

[361] Artificial intelligence refers to a field of study on artificial intelligence or methodologies for creating artificial intelligence, and machine learning refers to a field of study on methodologies for defining and solving various issues in the area of artificial intelligence. Machine learning is also defined as an algorithm for improving the performance of an operation through steady experiences of the operation.

[362] An artificial neural network (ANN) is a model used in machine learning and may refer to an overall problem-solving model that includes artificial neurons (nodes) forming a network by combining synapses. The artificial neural network may be defined by a pattern of connection between neurons of different layers, a learning process of updating a model parameter, and an activation function generating an output value.

[363] The artificial neural network may include an input layer, an output layer, and optionally one or more hidden layers. Each layer includes one or more neurons, and the artificial neural network may include synapses that connect neurons. In the artificial neural network, each neuron may output a function value of an activation function of input signals input through a synapse, weights, and deviations.

[364] A model parameter refers to a parameter determined through learning and includes a weight of synapse connection and a deviation of a neuron. A hyper-parameter refers to a parameter to be set before learning in a machine learning algorithm and includes a learning rate, the number of iterations, a mini-batch size, and an initialization function.

[365] Learning an artificial neural network may be intended to determine a model parameter for minimizing a loss function. The loss function may be used as an index for determining an optimal model parameter in a process of learning the artificial neural network.

[366] Machine learning may be classified into supervised learning, unsupervised learning, and reinforcement learning.

[367] Supervised learning refers to a method of training an artificial neural network with a label given for training data, wherein the label may indicate a correct answer (or result value) that the artificial neural network needs to infer when the training data is input to the artificial neural network. Unsupervised learning may refer to a method of training an artificial neural network without a label given for training data. Reinforcement learning may refer to a training method for training an agent defined in an environment to choose an action or a sequence of actions to maximize a cumulative reward in each state.

[368] Machine learning implemented with a deep neural network (DNN) including a plurality of hidden layers among artificial neural networks is referred to as deep learning, and deep learning is part of machine learning. Hereinafter, machine learning is construed as including deep learning.

[369] The foregoing technical features may be applied to wireless communication of a robot.

[370] Robots may refer to machinery that automatically process or operate a given task with own ability thereof. In particular, a robot having a function of recognizing an environment and autonomously making a judgment to perform an operation may be referred to as an intelligent robot.

[371] Robots may be classified into industrial, medical, household, military robots and the like according uses or fields. A robot may include an actuator or a driver including a motor to perform various physical operations, such as moving a robot joint. In addition, a movable robot may include a wheel, a brake, a propeller, and the like in a driver to run on the ground or fly in the air through the driver.

[372] The foregoing technical features may be applied to a device supporting extended reality.

[373] Extended reality collectively refers to virtual reality (VR), augmented reality (AR), and mixed reality (MR). VR technology is a computer graphic technology of providing a real-world object and background only in a CG image, AR technology is a computer graphic technology of providing a virtual CG image on a real object image, and MR technology is a computer graphic technology of providing virtual objects mixed and combined with the real world.

[374] MR technology is similar to AR technology in that a real object and a virtual object are displayed together. However, a virtual object is used as a supplement to a real object in AR technology, whereas a virtual object and a real object are used as equal statuses in MR technology.

[375] XR technology may be applied to a head-mount display (HMD), a head-up display (HUD), a mobile phone, a tablet PC, a laptop computer, a desktop computer, a TV, digital signage, and the like. A device to which XR technology is applied may be referred to as an XR device.

[376] The present disclosure may have various advantageous effects.

[377] For example, an AP / STA that has received IDC information from a counterpart STA may not transmit frames to the counterpart STA during IDC duration so that Wi-Fi performance degradation can be prevented.

[378] Advantageous effects which can be obtained through specific embodiments of the present disclosure are not limited to the advantageous effects listed above. For example, there may be a variety of technical effects that a person having ordinary skill in the related art can understand and / or derive from the present disclosure. Accordingly, the specific effects of the present disclosure are not limited to those explicitly described herein, but may include various effects that may be understood or derived from the technical features of the present disclosure.

[379] Claims in the present disclosure can be combined in a various way. For instance, technical features in method claims of the present disclosure can be combined to be implemented or performed in an apparatus, and technical features in apparatus claims can be combined to be implemented or performed in a method. Further, technical features in method claim(s) and apparatus claim(s) can be combined to be implemented or performed in an apparatus, and technical features in method claim(s) and apparatus claim(s) can be combined to be implemented or performed in a method.

Claims

1. A method comprising:receiving, by a station (STA), a frame; andtransmitting, by the STA, a multi-STA block acknowledgement (BA) frame comprising unavailability information related to the STA in response to the frame,wherein BA information field of the multi-STA BA frame comprises per association identifier (AID) traffic identifier (TID) information subfield related to the STA, andwherein the unavailability information is included in the per AID TID information subfield based on an AID TID information subfield of the per AID TID information subfield being set to a specific value.

2. The method of claim 1, wherein the unavailability information is included instead of a BA bitmap subfield in the per AID TID information subfield.

3. The method of claim 1, wherein the specific value of the AID TID information subfield is determined based on at least one of a value of an AID 11 subfield in the AID TID information subfield, a value of an acknowledgement (Ack) type subfield in the AID TID information subfield, or a value of a TID subfield in the AID TID information subfield.

4. The method of claim 3, wherein the value of the Ack type subfield is 0, and wherein the value of the TID subfield is 13.

5. The method of claim 4, wherein the value of the AID 11 subfield is not 2045.

6. The method of claim 1, wherein a subfield comprising the unavailability information is located after the AID TID information subfield in the per AID TID information subfield.

7. The method of claim 6, wherein the per AID TID information subfield comprises a BAstarting sequence control subfield,wherein the BA starting sequence control subfield is located after the AID TID information subfield in the per AID TID information subfield, andwherein the subfield comprising the unavailability information is located after the BA starting sequence control subfield in the per AID TID information subfield.

8. The method of claim 1, wherein the per AID TID information subfield comprises a BA starting sequence control subfield,wherein the BA starting sequence control subfield comprises a fragment number subfield, andwherein the fragment number subfield informs a length of a subfield including the unavailability information.

9. The method of claim 1, wherein the unavailability information comprises at least one of information for an unavailability start time or information for an unavailability duration,wherein the unavailability start time informs a value of timing synchronization function (TSF) at a time when the STA becomes unavailable, andwherein the unavailability duration informs a duration in a specific time unit over which the STA is unavailable.

10. The method of claim 9, wherein a subfield comprising the unavailability information is a feedback subfield, andwherein a subfield comprising the information for the unavailability duration is located after a subfield comprising the information for the unavailability start time in the feedback subfield.

11. The method of claim 1, wherein the multi-STA BA frame comprises information informing a presence of the unavailability information, andwherein a subfield comprising the information informing the presence of the unavailability information is located before a subfield comprising the unavailabilityinformation in the multi-STA BA frame.

12. The method of claim 11, wherein the subfield comprising the information informing the presence of the unavailability information is a feedback type subfield, andwherein the feedback type subfield is included in a BA starting sequence control subfield in the per AID TID information subfield.

13. The method of claim 12, wherein the BA starting sequence control subfield further comprises a fragment number subfield and a reserved subfield,wherein the feedback type subfield is located after the reserved subfield, and wherein the reserved subfield is located after the fragment number subfield.

14. The method of claim 12, wherein a value 0 of the feedback type subfield informs that the unavailability information related to in-device coexistence (IDC) is present.

15. The method of claim 11, wherein the information informing the presence of the unavailability information comprises an identifier (ID) of the unavailability information.

16. The method of claim 1, wherein the received frame comprises at least one of a buffer status report poll (BSRP) trigger frame or a quality of service (QoS) data frame.

17. A station (STA) comprising:a transceiver;a memory; andat least one processor operably coupled to the transceiver and the memory,wherein the memory stores instructions that, based on being executed by the at least one processor, perform operations comprising:receiving a frame; andtransmitting a multi-STA block acknowledgement (BA) frame comprisingunavailability information related to the STA in response to the frame,wherein BA information field of the multi-STA BA frame comprises per association identifier (AID) traffic identifier (TID) information subfield related to the STA, andwherein the unavailability information is included in the per AID TID information subfield based on an AID TID information subfield of the per AID TID information subfield being set to a specific value.

18. An apparatus comprising:at least one processor; andat least one memory operatively coupled to the at least one processor,wherein the at least one memory stores instructions that, based on being executed by the at least one processor, perform operations comprising:receiving a frame; andtransmitting a multi-STA block acknowledgement (BA) frame comprising unavailability information related to the STA in response to the frame,wherein BA information field of the multi-STA BA frame comprises per association identifier (AID) traffic identifier (TID) information subfield related to the STA, andwherein the unavailability information is included in the per AID TID information subfield based on an AID TID information subfield of the per AID TID information subfield being set to a specific value.

19. A non-transitory computer readable medium (CRM) having stored thereon a program code implementing instructions that, based on being executed by at least one processor, perform operations comprising:receiving a frame; andtransmitting a multi-STA block acknowledgement (BA) frame comprising unavailability information related to the STA in response to the frame,wherein BA information field of the multi-STA BA frame comprises per association identifier (AID) traffic identifier (TID) information subfield related to the STA, andwherein the unavailability information is included in the per AID TID information subfield based on an AID TID information subfield of the per AID TID information subfieldbeing set to a specific value.

20. A method comprising:transmitting, by an access point (AP), a frame to a station (STA); andreceiving, by the AP, a multi-STA block acknowledgement (BA) frame comprising unavailability information related to the STA in response to the frame,wherein BA information field of the multi-STA BA frame comprises per association identifier (AID) traffic identifier (TID) information subfield related to the STA, andwherein the unavailability information is included in the per AID TID information subfield based on an AID TID information subfield of the per AID TID information subfield being set to a specific value.

21. An access point (AP) comprising:a transceiver;a memory; andat least one processor operably coupled to the transceiver and the memory,wherein the memory stores instructions that, based on being executed by the at least one processor, perform operations comprising:transmitting a frame to a station (STA); andreceiving a multi-STA block acknowledgement (BA) frame comprising unavailability information related to the STA in response to the frame,wherein BA information field of the multi-STA BA frame comprises per association identifier (AID) traffic identifier (TID) information subfield related to the STA, andwherein the unavailability information is included in the per AID TID information subfield based on an AID TID information subfield of the per AID TID information subfield being set to a specific value.

Images