Patent Description:
A wireless local area network (WLAN) connects two or more apparatuses to each other by using a wireless signal transmission method for the transfer of information or data. The WLAN technology is based on the Institute of Electrical and Electronics Engineers (IEEE) <NUM> standard, which includes standards such as <NUM>. 11b, <NUM>. 11a, <NUM>, <NUM>. 11n, <NUM>. 11ac, and <NUM>. 11ax, or the like. This standard supports a wireless transmission speeds of up to about <NUM> Gbytes/s by using orthogonal frequency-division multiplexing (OFDM) technology.

11ac, data may be simultaneously transmitted to multiple users by using a multiuser (MU) multi-input multi-output (MIMO) (MU-MIMO) technique. 11ax, referred to as high efficiency (HE), multi-connection may be implemented by the MU-MIMO scheme and providing an available subcarrier to users in sharing manner based on orthogonal frequency-division multiplexing access (OFDMA). Therefore, the WLAN system to which <NUM>. 11ax is applied may effectively support communication in dense areas and outdoors.

11be, referred to as extremely high throughput (EHT), support of about <NUM> unlicensed spectrum, utilization of up to about <NUM> bandwidth per channel, introduction of hybrid automatic repeat and request (HARQ), support of up to 16x16 multi-input multi-output (MIMO), or the like will be implemented. Therefore, a next-generation WLAN system is expected to support effectively low latency and hyper-speed transmission, such as new radio (NR) that is <NUM> technology.

<NPL> discusses enhancements for high efficiency.

<CIT> discloses: A method, comprising: generating, at a first communication device, a first communication frame corresponding to a request to participate in a block acknowledgment procedure, wherein the first communication frame includes: a first field indicating a number of buffers requested to be allocated at a second communication device for buffering data units to be transmitted by the first communication device, and a second field indicating a first maximum bitmap length supported by the first communication device; transmitting, by the first communication device, the first communication frame to the second communication device; receiving, at the first communication device, a second communication frame corresponding to a response to the first communication frame, wherein the second communication frame includes: a third field indicating a number of buffers allocated at the second communication device for buffering the data units transmitted by the first communication device, and a fourth field indicating a second maximum bitmap length supported by the second communication device; and performing, at the first communication device, the block acknowledgment procedure in accordance with the second maximum bitmap length.

<CIT> discloses: A method for use in a station of transmitting acknowledgements in response to data packets in wireless communication, the method comprising: receiving data packets from a plurality of stations; generating acknowledgements for the data packets; obtaining a transmission opportunity; and transmitting the acknowledgements for the data packets to the plurality of stations in a single transmission.

The inventive concept provides an apparatus and method for providing reduced duration for block acknowledgement.

Specific embodiments are defined in the dependent claims.

The present disclosure relates generally to wireless communications, and more particularly to an apparatus and method for block acknowledgement within a reduced duration.

Wireless communications over a radio channel may include errors in transmitted packets (e.g., under the influence of interferences among devices in the wireless communications system, multi-path fading, noises, etc.). Techniques for mitigating such errors may include a Forward Error Correction Code (FEC) scheme in which the probability of communication error occurrence may be lowered by a transmitting device additionally sending redundant information (e.g., such that copies of redundant information may have each have a likelihood of being successfully received by a receiving device. Further, Automatic Repeat Request (ARQ) scheme may be implemented in some wireless communication systems, in which packets may be retransmitted when errors have occurred. A Hybrid Automatic Retransmission Request (HARQ) scheme may be a hybrid scheme combining aspects of FEC and ARQ.

In addition to an ARQ scheme in which reception results are acknowledged on a packet-by-packet basis, a block ARQ scheme in which reception results of a plurality of transmitted packets are acknowledged as a group may be implemented (e.g., through block ARQ messaging). That is, a transmitting device (e.g., access points) and a receiving device (e.g., stations) may communicate with each other based on a block acknowledgement mechanism for more efficient ARQ functionality. For example, a plurality of medium access control (MAC) protocol data units (PDU) (MPDU) may be received, by a recipient device from an originator device, as messages exchanged between medium access control (MAC) entities. Instead of transmitting (by a recipient device to an originator device) a plurality of acknowledgements (ACKs) corresponding to each of a plurality of MPDUs, a receiving device may transmit one block acknowledgement to a transmitting device in response to an aggregated MPDU (A-MPDU).

As a result, a block acknowledgement may include a bitmap, and each bit of the bitmap may indicate a status of the received MPDU (for example, success or failure, ACK or NACK, etc.). In the block acknowledgement mechanism, a device, which transmits data (for example, one or more MPDUs) and receives block acknowledgement, may be referred to as an originator or a sender, and a device receiving data and transmitting block acknowledgement may be referred to as a recipient or a receiver. In some cases, block acknowledgement may be referred to as BA, Block Ack, etc..

The originator may set a period in which other devices are prevented from accessing a channel while data is transmitted to the recipient and block acknowledgement is received from the recipient. For example, the MPDU transmitted by the originator may include a duration field that defines a length of the period (for example, a duration) for receiving block acknowledgement. Other devices (for example, one or more other stations) may identify the duration based on the duration field, and transmission of signals by other devices may be blocked during the duration (e.g., such that other devices do not transmit signals that may interfere with the MPDU and/or corresponding BA during the duration). Accordingly, when only a portion of the duration is used for transmission of block acknowledgement, waste of radio resource (for example, a frequency band and/or time) or airtime may occur.

According to the techniques described herein, an originator may reduce a duration for transmission of a block acknowledgement, and a recipient may transmit the block acknowledgement to the originator according to the reduced duration. Accordingly, radio resource waste may be prevented, a transmission rate may be increased, and the efficiency of the wireless communication system may be improved. Various embodiments of the present disclosure are described in more detail below in conjunction with accompanying drawings.

<FIG> is a diagram illustrating a wireless communication system <NUM> according to an example embodiment. <FIG> illustrates a wireless local area network (WLAN) system as an example of the wireless communication system <NUM>.

To describe embodiments of the inventive concept, an orthogonal frequency-division multiplexing (OFDM) or OFDM-access (A) (OFDMA)-based wireless communication system, in particular, the IEEE <NUM> standard, will be used as the primary focus. However, a primary subject of the inventive concept may be applicable with some modifications within the scope of the inventive concept to other communication systems with similar technical backgrounds and channel types (for example, long term evolution (LTE), LTE-advanced (A) (LTE-A), new radio (NR), wireless broadband (WiBro), and a cellular system such as global system for mobile communication (GSM), and a short-range communication system such as Bluetooth and near field communication (NFC)), which will be feasible according to one of ordinary skill in the art.

In addition, various functions described below may be implemented or supported by artificial intelligence technology or one or more computer programs, and each of the computer programs may include computer-readable program code and may be executed on a computer-readable medium. The terms "application" and "program" may refer to one or more computer programs, software components, instruction sets, procedures, functions, objects, classes, instances, related data, or portions thereof suitable for implementation of suitable computer-readable program code. The term "computer-readable program code" may include all types of computer code with a source code, object code, and executable code. The term "computer-readable medium" may include all types of media that may be accessed by a computer, such as read-only memory (ROM), random access memory (RAM), a hard disk drive, a compact disk (CD), a digital video disk (DVD), or some other type of memory. The term "non-transitory" computer-readable media may exclude wired, wireless, optical, or other communication links that transmit transient electrical signals or other signals. The non-transitory computer-readable media may include media on which data may be permanently stored, and media on which data may be stored and later overwritten, such as a rewritable optical disk or erasable memory device.

In various embodiments of the inventive concept described below, a hardware method will be described as an example. However, because various embodiments of the inventive concept include technology using both hardware and software, various embodiments of the inventive concept do not exclude a software-based method.

In addition, a term referring to control information, a term referring to an entry, a term referring to a network entity, a term referring to messages, a term referring to components of an apparatus, or the like may be given for the convenience of description. Thus, the inventive concept is not limited to the terms to be described later, and other terms with equivalent technical meaning may be used.

Referring to <FIG>, the wireless communication system <NUM> may include a first access point AP1, a second access point AP2, a first station STA1, a second station STA2, a third station STA3, and a fourth station STA4. The first and second access points AP <NUM> and AP2 may be connected to a network <NUM> including the Internet, an internet protocol (IP) network, or other arbitrary networks. The first access point AP1 may provide a connection for the network <NUM> in a first coverage area <NUM> to the first station STA1, the second station STA2, the third station STA3, and the fourth station STA4, and the second access point AP2 may also provide a connection for the network <NUM> in a second coverage area <NUM> to the third and fourth stations STA3 and STA4. In some embodiments, the first and second access points AP1 and AP2 may communicate with at least one of the first station STA1, the second station STA2, the third station STA3, and the fourth station STA4, based on wireless fidelity (Wi-Fi) or other arbitrary WLAN connection technology.

An access point may be referred to as a router, a gateway, or the like, and a station may be referred to as a mobile station, a subscriber station, a terminal, a mobile terminal, a wireless terminal, a user equipment, a user, etc. A station may include a mobile device such as a mobile phone, a laptop computer, and a wearable apparatus, and may include a stationary apparatus such as a desktop computer and a smart TV.

The access point may allocate at least one resource unit (RU) to at least one station. The access point may transmit data via at least one allocated RU, and at least one station may receive data via at least one allocated RU. 11ax (hereinafter, high efficiency (HE)), the access point may allocate a single RU to at least one station, while in <NUM>. 11be (hereinafter, extremely high throughput (EHT)) or next-generation IEEE <NUM> standards (hereinafter, EHT +), the access point may allocate a multi-RU (MRU) including two or more RUs to at least one station. For example, the first access point AP1 may allocate MRU to at least one of the first station STA1, the second station STA2, the third station STA3, and the fourth station STA4, and may transmit data via the allocated MRU.

The access points and the stations may communicate with each other based on a block acknowledgement mechanism. For example, as will be described later with reference to <FIG>, a receiving device may transmit one block acknowledgement to a transmitting device, instead of transmitting to the transmitting device a plurality of acknowledges (Acks) corresponding to each of a plurality of medium access control (MAC) protocol data units (PDU) (MPDU), which have been received from the transmitting device as messages exchanged between MAC entities. As a result, block acknowledgement may include a bitmap (for example, a block acknowledgement bitmap subfield in <FIG>), and each bit of the bitmap may indicate a status of the received MPDU (for example, success or failure). In the block acknowledgement mechanism, a device, which transmits data (for example, MPDU) and receives block acknowledgement, may be referred to as an originator or a sender, and a device receiving data and transmitting block acknowledgement may be referred to as a recipient or a receiver. In some cases, block acknowledgement may be referred to as BA, Block Ack, etc..

The originator may set a period in which other devices are prevented from accessing a channel while data is transmitted to the recipient and block acknowledgement is received from the recipient. For example, as will be described later with reference to <FIG>, the MPDU transmitted by the originator may include a duration field that defines a length of the period (for example, a duration) for receiving block acknowledgement. Other devices (for example, one or more other stations) may identify the duration based on the duration field, and transmission of signals by other devices may be blocked during the duration (e.g., such that other devices do not transmit signals that may interfere with the MPDU and/or corresponding BA during the duration). Accordingly, as described later with reference to <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, or the like, when only a portion of the duration is used for transmission of block acknowledgement, waste of radio resource (for example, a frequency band and/or time) or airtime may occur.

As described later with reference to drawings, an originator may reduce a duration for transmission of a block acknowledgement, and a recipient may transmit the block acknowledgement to the originator according to the reduced duration. Accordingly, radio resource waste may be prevented, a transmission rate may be increased, and the efficiency of the wireless communication system <NUM> may be improved. Hereinafter, example embodiments will be described for example, with reference to HE and/or EHT, but it should be understood that example embodiments are also applicable to EHT+.

<FIG> is a block diagram of a wireless communication system <NUM> according to an example embodiment. The block diagram of <FIG> may illustrate a first wireless communication apparatus <NUM> and a second wireless communication apparatus <NUM> communicating with each other in the wireless communication system <NUM>. Each of the first wireless communication apparatus <NUM> and the second wireless communication apparatus <NUM> may include an arbitrary apparatus communicating in the wireless communication system <NUM>, and may be referred to as an apparatus for wireless communication. In some embodiments, each of the first wireless communication apparatus <NUM> and the second wireless communication apparatus <NUM> may include an access point or station of a WLAN system.

Referring to <FIG>, the first wireless communication apparatus <NUM> may include an antenna 21_2, a transceiver 21_4, and processing circuitry 21_6. In some embodiments, the antenna 21_2, the transceiver 21_4, and the processing circuitry 21_6 may be included in one package, or may be respectively included in different packages. The second wireless communication apparatus <NUM> may also include an antenna 22_2, a transceiver 22_4, and a processing circuit 22_6. Hereinafter, duplicate descriptions of the first wireless communication apparatus <NUM> and the second wireless communication apparatus <NUM> will be omitted.

The antenna 21_2 may receive a signal from the second wireless communication apparatus <NUM> and provide the signal to the transceiver 21_4, and may transmit the signal provided from the transceiver 21_4 to the second wireless communication apparatus <NUM>. In some embodiments, the antenna 21_2 may include a plurality of antennas for multi-input multi-output (MIMO). In addition, in some embodiments, the antenna 21_2 may include a phased array for beamforming.

The transceiver 21_4 may process the signal received from the second wireless communication apparatus <NUM> via the antenna 21_2, and provide the processed signal to the processing circuitry 21_6. In addition, the transceiver 21_4 may process a signal provided by the processing circuitry 21_6, and may output the processed signal via the antenna 21_2. In some embodiments, the transceiver 21_4 may include an analog circuit such as a low noise amplifier, a mixer, a filter, a power amplifier, and an oscillator. In some embodiments, the transceiver 21_4 may process the signal received from the antenna 21_2 and/or the signal received from the processing circuitry 21_6 based on the control of the processing circuitry 21_6.

The processing circuitry 21_6 may extract information transmitted by the second wireless communication apparatus <NUM> by processing the signal received from the transceiver 21_4. For example, the processing circuitry 21_6 may extract information by demodulating and/or decoding the signal received from the transceiver 21_4. In addition, the processing circuitry 21_6 may generate a signal including information to be transmitted to the second wireless communication device <NUM>, and provide the generated signal to the transceiver 21_4. For example, the processing circuitry 21_6 may provide, to the transceiver 21_4, the signal generated by encoding and/or modulating data to be transmitted to the second wireless communication apparatus <NUM>. In some embodiments, the processing circuitry 21_6 may include a programmable component such as a central processing unit (CPU) and a digital signal processor (DSP), and a reconfigurable component such as a field programmable gate array (FPGA), and may include a component that provides a fixed-function such as an intellectual property (IP) core. In some embodiments, the processing circuitry 21_6 may include a memory storing data and/or a series of instructions, or may access the corresponding memory.

Herein, that the transceiver 21_4 and/or the processing circuitry 21_6 perform operations may be referred to as that the first wireless communication apparatus <NUM> performs the corresponding operations. Accordingly, operations performed by an access point may be performed by a transceiver and/or processing circuitry, and operations performed by a station may be performed by a transceiver and/or processing circuitry included in a station.

A transceiver may communicate bi-directionally, via antennas, wired, or wireless links as described above. For example, the transceiver may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver may also include or be connected to a modem to modulate the packets and provide the modulated packets to for transmission, and to demodulate received packets. In some examples, transceiver may be tuned to operate at specified frequencies. For example, a modem can configure the transceiver to operate at a specified frequency and power level based on the communication protocol used by the modem.

In some aspects processing circuitry may include, or may be implemented by, a processor. A processor is an intelligent hardware device, (e.g., a general-purpose processing component, a digital signal processor (DSP), a central processing unit (CPU), a graphics processing unit (GPU), a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, the processor is configured to operate a memory array using a memory controller. In other cases, a memory controller is integrated into the processor. In some cases, the processor is configured to execute computer-readable instructions stored in a memory to perform various functions. In some embodiments, a processor includes special purpose components for modem processing, baseband processing, digital signal processing, or transmission processing.

In some aspects, techniques described herein may be implemented based on software. Software may include code to implement aspects of the present disclosure. Software may be stored in a non-transitory computer-readable medium such as system memory or other memory. In some cases, the software may not be directly executable by the processor but may cause a computer (e.g., when compiled and executed) to perform functions described herein.

<FIG> is a diagram illustrating a block acknowledgement mechanism according to the prior art. <FIG> includes a timing diagram illustrating a process of transceiving (e.g., transmitting by an originator and receiving by a recipient) data DATA and block acknowledgement BA between the originator and the recipient, and illustrates an aggregated (A)-MPDU (A-MPDU) <NUM> included in the data DATA and a block acknowledgement frame <NUM> included in the block acknowledgement BA.

Referring to <FIG>, the originator may transmit the data DATA to the recipient, and the data DATA may include a plurality of MPDUs. In some embodiments, the data DATA may include the A-MPDU <NUM>. As illustrated in <FIG>, the A-MPDU <NUM> may include a series of subframes, one subframe may include an MPDU delimiter, the MPDU, and a padding field, and the MPDU may include a duration field 31_1.

In some cases, a MAC frame (e.g., a data frame, an A-MPDU <NUM>, etc.) may include information for block acknowledgment techniques described herein. For instance, A-MPDU <NUM> may include a control field or a sequence control field (e.g., such as a sequence control field <NUM> described with reference to <FIG>). A control field may generally include information for performing block acknowledgement procedures between an originator and a recipient.

As an example, a transmitter (e.g., an originator, a transmitting device, etc.) may transmit three packets (e.g., an A-MPDU <NUM> may include three MPDUs), such as MPDU#<NUM>, MPDU#<NUM> and MPDU#<NUM>, in sequence. In the A-MPDU <NUM>, the three packets (MPDU#<NUM> to MPDU#<NUM>) may have the same Destination Address (DA). Each of the packets (MPDU#<NUM> to MPDU#<NUM>) may be provided with a Sequence Number (SN) and a Fragmentation Number (FN). The SN may indicate an order in which packets are transmitted by a transmitting device (e.g., from an upper layer). In some examples, packets having a same SN may be transmitted over a plurality of packets (e.g., as channel conditions or channel state information demands). The FN may indicate the order the plurality of packets was transmitted in (e.g., divided over the transmission of packets having the same SN).

A receiver (e.g., a recipient, a receiving device, etc.) may determine whether or not packets are continuously received, may determine which packets are not received, etc., by comparing the SN and the FN of received packets with those of previously received packets. Aspects of SN and FN may be described in more detail herein, for example, with reference to <FIG>. For instance, a FN field may include four bits, some of which may be used to indicate block acknowledgement bitmap subfield lengths corresponding to negotiated buffer sizes, as described in more detail herein.

As described above with reference to <FIG>, the originator may set a duration D by using the duration field 31_1. For example, as illustrated in <FIG>, the block acknowledgement BA may be transmitted during the duration D, and during the duration D, the transmission of a signal from other devices except for the originator and the receiver may be blocked.

The block acknowledgement BA may include the block acknowledgement frame <NUM>, and as illustrated in <FIG>, the block acknowledgement frame <NUM> may include a frame control field, a duration field, a receiver address (RA) field, a transmitter address (TA) field, a block acknowledgement control field, a block acknowledgement information field, and a frame check sequence (FCS) field. The block acknowledgement control field may define a type of block acknowledgement. For example, the block acknowledgement control field may include a block acknowledgement type subfield representing one of various block acknowledgement types. As illustrated in <FIG>, when the block acknowledgement type subfield indicates a compressed block acknowledgement, the block acknowledgement information field may include the block acknowledgement start sequence control subfield and the block acknowledgement bitmap subfield. In addition, when the block acknowledgement type subfield represents a multi-station (STA) block acknowledgement, the block acknowledgement information field may include at least one Per association identifier (AID) traffic identifier (TID) Info subfield corresponding to at least one station, and the Per AID TID Info subfield may include an AID TID Info subfield, the block acknowledgement start sequence control subfield, and the block acknowledgement bitmap subfield. An AID TID subfield may include an AID <NUM> subfield with an identifier of a station (or the AID). Hereinafter, example embodiments may be described with reference to compressed block acknowledgement frames, but the techniques described herein are not limited thereto.

The block acknowledgement start sequence control subfield may represent a start sequence of sequences indicated by the following block acknowledgement bitmap subfield. For example, as described above, the data DATA received from the originator may include a plurality of MPDUs, and the recipient may set the block acknowledgement start sequence control subfield to indicate the start sequence, for representing a success or a failure of receiving some of the plurality of MPDUs by using the block acknowledgement bitmap subfield. As described above with reference to <FIG>, each bit of the block acknowledgement bitmap subfield may correspond to the sequence included in the data DATA, for example, the MPDU, and may represent a status (for example, a success or a failure) of the MPDU. As to be described later with reference to <FIG> and <FIG>, a length (for example, the number of bits) of the block acknowledgement bitmap subfield may have a plurality of variants, and accordingly, a length of block acknowledgement may be dependent on the length of the block acknowledgement bitmap subfield. Herein, the block acknowledgement bitmap subfield may be referred to as the block acknowledgement bitmap.

The originator and the recipient may perform a negotiation before transmitting the data DATA for the block acknowledgement mechanism. For example, as to be described later with reference to <FIG> and <FIG>, the originator and the recipient may negotiate a size of a buffer to be used for transmission and receiving of the data DATA. The length of the block acknowledgement bitmap subfield described above may be related to the negotiated buffer size, and accordingly, as to be described later with reference to <FIG> and <FIG>, a protocol standard may define at least one size of the block acknowledgement bitmap subfield, corresponding to the buffer size. The recipient may select one of at least one size of the block acknowledgement bitmap subfield based on the negotiated buffer size, the sequences preserved in the buffer, and the status of the sequences included in the data DATA, and may generate the block acknowledgement bitmap subfield of the selected size. In some embodiments, a block control field of the block acknowledgement frame <NUM> may include a value representing the selected size of the block acknowledgement bitmap subfield, and the originator may identify the length of the block acknowledgement bitmap subfield based on the block acknowledgement control field.

Depending on the length of the block acknowledgement bitmap subfield, the radio resource waste may occur during the duration D. For example, a protocol standard (for example, HE) may stipulate that the originator defines the duration D, considering the maximum size of the block acknowledgement bitmap subfield corresponding to the negotiated buffer size. Accordingly, when the recipient generates a block acknowledgement bitmap subfield with a size of less than the maximum size, even though transmission of the block acknowledgement BA is completed at an earlier time point, as illustrated in <FIG>, the transmission of a signal by other devices except for the originator and the recipient may be blocked during a period T from a time point at which transmission of the block acknowledgement BA has been completed to a time point at which the duration D ends. Particularly, as to be described later with reference to <FIG> and <FIG>, as the buffer size increases in a next-generation protocol standard, the maximum length of the block acknowledgement bitmap subfield may be increased, and accordingly, the radio resource waste may be increased. The originator may reduce the duration D to prevent the radio resource waste, and various examples of reducing the duration D by the originator will be described with reference to diagrams below.

<FIG> and <FIG> are diagrams representing buffer sizes and block acknowledgement bitmap subfield lengths, according to the prior art. <FIG> illustrates a table 40a with the negotiated buffer size and the block acknowledgement bitmap subfield length in HE, and <FIG> illustrates a table 40b with the negotiated buffer size and the block acknowledgement bitmap subfield length in EHT. Hereinafter, <FIG> and <FIG> will be described with reference to <FIG>.

Referring to <FIG>, in HE, the originator and the recipient may negotiate the buffer size as one of <NUM> through <NUM>, and the block acknowledgement bitmap subfield length may be determined according to a range of the negotiated buffer size. For example, as illustrated in <FIG>, when the negotiated buffer size is between <NUM> and <NUM>, the block acknowledgement bitmap subfield length may be <NUM> or <NUM> in the compressed block acknowledgement frame, and may be <NUM>, <NUM>, <NUM>, or <NUM> in the multi-STA block acknowledgement frame. Accordingly, when the originator has set the duration field to represent a duration for the block acknowledgement bitmap subfield with a length of <NUM>, but the originator generates the block acknowledgement bitmap subfield with a length less than <NUM>, radio resource waste may occur.

Referring to <FIG>, in EHT, the originator and the recipient may negotiate the buffer size as one of <NUM> through <NUM>, and the block acknowledgement bitmap subfield length may be determined according to a range of the negotiated buffer size. In comparison to the table 40a of <FIG>, the table 40b of <FIG> may show that the buffer size and the block acknowledgement bitmap subfield length increase. For example, as illustrated in <FIG>, when the negotiated buffer size is between <NUM> and <NUM>, the block acknowledgement bitmap subfield length may be <NUM>, <NUM>, <NUM>, or <NUM> in the compressed block acknowledgement frame, and may be <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> in the multi-STA block acknowledgement frame. Accordingly, when the originator has set the duration field to represent a duration for the block acknowledgement bitmap subfield with a length of <NUM>, but the originator generates the block acknowledgement bitmap subfield with a length less than <NUM>, radio resource waste may occur. Hereinafter, example embodiments will be described with reference to mainly the table 40b of FIG.

<FIG> and <FIG> are graphs of examples of radio resource waste, according to the prior art. Each of the graphs of <FIG> and <FIG> illustrates, when the negotiated buffer size is <NUM>, the radio resource waste according to the block acknowledgement bitmap subfield length at a different transmission rate.

Referring to <FIG>, when the block acknowledgement bitmap subfield length is <NUM> that corresponds to the negotiated buffer size, the radio resource waste may not substantially occur. Additionally, or alternatively, in the state where a transmission speed of the block acknowledgement is about <NUM> Mbps, when the block acknowledgement bitmap subfield length is <NUM>, radio resource waste of about <NUM> may occur, and when the block acknowledgement bitmap subfield length is <NUM>, radio resource waste of about <NUM> may occur, when the block acknowledgement bitmap subfield length is <NUM>, radio resource waste of about <NUM> may occur.

Referring to <FIG>, when the block acknowledgement bitmap subfield length is <NUM> that corresponds to the negotiated buffer size, radio resource waste may not substantially occur. Additionally, or alternatively, in the state where a transmission speed of the block acknowledgement is about <NUM> Mbps, when the block acknowledgement bitmap subfield length is <NUM>, radio resource waste of about <NUM> may occur, when the block acknowledgement bitmap subfield length is <NUM>, radio resource waste of about <NUM> may occur, and when the block acknowledgement bitmap subfield length is <NUM>, radio resource waste of about <NUM> may occur. Due to the transmission speed (for example, about <NUM> Mbps) being greater than the transmission speed (for example, about <NUM> Mbps) in <FIG>, in the example of <FIG>, radio resource waste may be relatively (for example, about one over four) reduced.

<FIG> is a timing diagram of a block acknowledgement mechanism according to an example embodiment. In <FIG>, a first case (e.g., Case <NUM>) may represent an example in which the duration is not reduced, and a second case (e.g., Case <NUM>) may represent an example in which the duration is reduced.

Referring to the upper portion of <FIG>, the originator may generate a block acknowledgement bitmap subfield with the maximum length of at least one length of the block acknowledgement bitmap subfield corresponding to the negotiated buffer size. For example, in the first case in <FIG>, the originator and the recipient may negotiate the buffer size as <NUM>, and next, the originator may transmit first data DATA1 to the recipient. The recipient may transmit, to the originator, a first block acknowledgement BA1 including a block acknowledgement bitmap subfield with the maximum length (for example, <NUM>) of block acknowledgement bitmap subfield lengths (for example, <NUM>, <NUM>, <NUM>, and <NUM>) corresponding to the buffer size of <NUM>. Accordingly, as described above with reference to <FIG> and <FIG> and illustrated in <FIG>, radio resource waste may not occur during a first duration D1.

Referring to the lower portion of <FIG>, the originator may generate a block acknowledgement bitmap subfield with a length less than the maximum length of at least one length of the block acknowledgement bitmap subfield corresponding to the negotiated buffer size. For example, in the second case in <FIG>, the originator and the recipient may negotiate the buffer size as <NUM>, and next, the originator may transmit second data DATA2 to the recipient. The recipient may transmit, to the originator, a second block acknowledgement BA2 including the block acknowledgement bitmap subfield with a length (for example, <NUM>, <NUM>, or <NUM>) less than the maximum length (for example, <NUM>) of the block acknowledgement bitmap subfield lengths (for example, <NUM>, <NUM>, <NUM>, and <NUM>) corresponding to the buffer size of <NUM>.

The originator may reduce the duration, considering various factors despite of the negotiated buffer size (for example, <NUM>). According to the invention the originator estimates the block acknowledgement bitmap subfield length based on a size of the second data DATA2, for example, the number of MPDUs included in the second data DATA2, and estimates a second duration D2 based on the estimated block acknowledgement bitmap subfield length and a transmission speed of the block Accordingly, as illustrated in <FIG>, the transmission of the second block acknowledgement BA2 may be completed during the second duration D2, which is reduced by a period T (e.g., or a duration T, a time T, etc.) from the first duration D1. In other words, the duration D2 may be shorter than the first block acknowledgement BA1, which is transmitted during the first duration D1.

As an example, according to techniques described herein, a first duration (e.g., D2) defined by a duration field may be less than a second duration (e.g., D1) for a second block acknowledgement (e.g., BA1) that may, in some examples, comprise a second block acknowledgement bitmap with a maximum length (e.g., from among at least one block acknowledgement bitmap corresponding to the negotiated buffer size as described in more detail herein, for example, with reference to <FIG> and <FIG>).

<FIG> and <FIG> are message diagrams of examples of methods for the block acknowledgement during a reduced duration, according to example embodiments. Message diagrams of <FIG> and <FIG> may illustrate operations of originators 71a and 71b and recipients 72a and 72b according to time. In some embodiments, the originators 71a and 71b and the recipients 72a and 72b may negotiate factors for reducing the duration in a negotiation process. Hereinafter, duplicate descriptions to be given with reference to <FIG> and <FIG> will be omitted.

Referring to <FIG>, the originator 71a and the recipient 72a negotiate the buffer size in operation S71a. For example, as described above with reference to <FIG>, in HE, the originator 71a and the recipient 72a may negotiate the buffer size as one of <NUM> through <NUM>. In addition, as described above with reference to <FIG>, in EHT, the originator 71a and the recipient 72a may negotiate the buffer size as one of <NUM> through <NUM>. In some embodiments, the originator 71a and the recipient 72a may negotiate the buffer size by transceiving each other a negotiation message (for example, a request or a response).

In operation S72a, the originator 71a and the recipient 72a negotiate an upper bound of the block acknowledgement bitmap subfield length. For example, the originator 71a and the recipient 72a may, as to be described later with reference to <FIG> and <FIG>, negotiate the upper bound of the block acknowledgement bitmap subfield length by transceiving each other a negotiation message (for example, a request or a respond) including a field representing the upper bound of the block acknowledgement bitmap subfield length. In some embodiments, the originator 71a and the recipient 72a may negotiate the upper bound of the block acknowledgement bitmap subfield length by transceiving each other an add block acknowledgement (ADDBA) request and an ADDBA respond, and the ADDBA request and/or the ADDBA respond may include a field representing the upper bound of the block acknowledgement bitmap subfield length.

As described above with reference to <FIG> and the like, a length of a block acknowledge depends on a block acknowledgement bitmap subfield length, and accordingly, a duration of the block acknowledge is limited due to a negotiated upper bound of the block acknowledgement bitmap subfield length.

In operation S73a, the originator 71a may set the duration field. For example, the originator 71a may determine the duration for the block acknowledge, based on the negotiated buffer size in operation S71a and the negotiated upper bound of the block acknowledgement bitmap subfield length in operation S72a, and may set the duration field to represent the determined duration. When the upper bound of the block acknowledgement bitmap subfield length negotiated in operation S72a is less than the maximum length of the block acknowledgement bitmap subfield lengths corresponding to the buffer size negotiated in operation S71a, the duration field may have a value representing the reduced duration.

In operation S74a, the originator 71a transmits data, and the recipient 72a receives data. For example, the originator 71a may transmit data including a plurality of MPDUs to the recipient 72a. Operation 73a described above may be related to operation S74a, subsequent thereto, in which data is transmitted, and accordingly, in the inventive concept, operations S73a and S74a may be collectively referred to as an operation in which the originator 71a provides data to the recipient 72a.

In operation S75a, the recipient 72a generates the block acknowledgement bitmap subfield. For example, the recipient 72a may generate the block acknowledgement bitmap subfield representing statuses of the MPDUs (or sequences) included in data received in operation S74a, and the generated block acknowledgement bitmap subfield has a length equal to or less than the upper bound negotiated in operation S72a.

In operation S76a, the recipient 72a transmits the block acknowledgement, and the originator 71a receives the block acknowledgement. The block acknowledgement includes the block acknowledgement bitmap subfield generated in operation S75a. When the upper bound of the block acknowledgement bitmap subfield length negotiated in operation S72a is less than the maximum length of the block acknowledgement bitmap subfield lengths corresponding to the buffer size negotiated in operation S71a, the block acknowledgement is transmitted during the reduced duration.

Referring to <FIG>, the originator 71b and the recipient 72b negotiate the buffer size in operation S71b. Next, the originator 71b and the recipient 72b negotiate an upper bound of the duration in operation S72b. For example, the originator 71b and the recipient 72b may negotiate the upper bound of the duration for the block acknowledgement by transceiving each other a negotiation message (for example, a request or a response) including a field representing the upper bound of the duration for the block acknowledgement.

In operation S73b, the originator 71b may set the duration field. For example, the originator 71b may determine the duration for the block acknowledge, based on the buffer size negotiated in operation S71b and the upper bound of the duration negotiated in operation S72b, and may set the duration field to represent the determined duration. When the upper bound of the duration in operation S72b is less than the duration corresponding to the maximum length of the block acknowledgement bitmap subfield lengths corresponding to the buffer size negotiated in operation S71b, the duration field has a value representing the reduced duration.

In operation S74b, the originator 71b transmits data, and the recipient 72b receives data. For example, the originator 71b may transmit data including a plurality of MPDUs to the recipient 72b. Operation 73b described above may be related to operation S74b, subsequent thereto, in which data is transmitted, and accordingly, in the inventive concept, operations S73b and S74b may be collectively referred to as an operation in which the originator 71b provides data to the recipient 72b.

In operation S75b, the recipient 72b generates the block acknowledgement bitmap subfield. For example, the recipient 72b may generate the block acknowledgement bitmap subfield representing statuses of the MPDUs (or sequences) included in data received in operation S74b, and the generated block acknowledgement bitmap subfield has a length so that the block acknowledgement including the block acknowledgement bitmap subfield has a duration equal to or less than the upper bound negotiated in operation S72b.

In operation S76b, the recipient 72b transmits the block acknowledgement, and the originator 71b receives the block acknowledgement. For example, the recipient 72b may identify the duration negotiated in operation S72b, and may transmit the block acknowledgement during the identified duration. When the upper bound of the duration in operation S72b is less than the duration corresponding to the maximum length of the block acknowledgement bitmap subfield lengths corresponding to the buffer size negotiated in operation S71b, the block acknowledgement is transmitted during the reduced duration.

<FIG> and <FIG> are diagrams of encoding of fields representing upper bounds of block acknowledgement bitmap subfield lengths, according to example embodiments. <FIG> illustrates a table 80a defining encoding of fields for the compressed block acknowledgement, and <FIG> illustrates a table 80b defining encoding of fields for the multi-STA block acknowledgement. In some embodiments, encoding of a field defined by the table 80b of <FIG> may be used. Hereinafter, a field representing the upper bound of the block acknowledgement bitmap subfield length may be referred to as an upper bound field. Hereinafter, <FIG> and <FIG> will be described with reference to <FIG>.

In some embodiments, the upper bound field in <FIG> and <FIG> may be used to negotiate the block acknowledgement bitmap subfield length. For example, as described above with reference to <FIG>, the upper bound field may include a message transceived by the originator and the recipient for negotiation of the upper bound of the block acknowledgement bitmap subfield length. In some embodiments, the upper bound field in <FIG> and <FIG> may be used by the originator to limit the block acknowledgement bitmap subfield length included in the block acknowledgement corresponding to data transmission. For example, as to be described later with reference to <FIG>, the upper bound field may be included in data transmitted by the originator, and the recipient may identify the upper bound of the block acknowledgement bitmap subfield length based on the upper bound field.

Referring to <FIG>, the upper bound field may represent one of available block acknowledgement bitmap subfield lengths (for example, <NUM>, <NUM>, <NUM>, and <NUM>) in the compressed block acknowledgement. For example, as illustrated in <FIG>, the upper bound field may have a length of <NUM> bits, and may have a value representing one of four block acknowledgement bitmap subfield lengths.

Referring to <FIG>, the upper bound field may represent one of available block acknowledgement bitmap subfield lengths (for example, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>) in the multi-STA block acknowledgement. For example, as illustrated in <FIG>, the upper bound field may have a length of <NUM> bits, and may have a value representing one of six block acknowledgement bitmap subfield lengths. In addition, some values (for example, <NUM> and <NUM>) of the upper bound field may be reserved.

<FIG> and <FIG> are message diagrams of examples of methods for block acknowledgement during the reduced duration, according to example embodiments. The message diagrams of <FIG> and <FIG> illustrate operations of an originator <NUM> and a recipient <NUM> according to time According to the invention, the originator <NUM> limits the block acknowledgement bitmap subfield length included in the block acknowledgement corresponding to data transmitted to the recipient <NUM>.

Referring to <FIG>, the originator <NUM> and the recipient <NUM> negotiate the buffer size in operation S91a. For example, the originator <NUM> and the recipient <NUM> may negotiate the buffer size by transceiving each other a negotiation message.

In operation S92a, the originator <NUM> limits the block acknowledgement bitmap subfield length. The originator <NUM> limits the length of the block acknowledgement bitmap subfield included in the block acknowledgement received in operation S97a corresponding to data transmitted in operation S94a to be described later. As to be described later with reference to <FIG>, the originator <NUM> provides the upper bound of the block acknowledgement bitmap subfield length to the recipient <NUM>, and accordingly, may explicitly limit the block acknowledgement bitmap subfield length.

In operation S93a, the originator <NUM> may set the upper bound field. The upper bound field, as described above with reference to <FIG> and <FIG>, may have a value representing the upper bound of the block acknowledgement bitmap subfield length, and may be included in data provided to the recipient <NUM> in operation 94a. The originator <NUM> determines the duration for the block acknowledgement based on the limited block acknowledgement bitmap subfield length (S92a), and sets the upper bound field based on the determined duration.

In operation S94a, the originator <NUM> transmits data, and the recipient <NUM> receives data. For example, the originator <NUM> may transmit data including a plurality of MPDUs to the recipient <NUM>. In addition, data may include the upper bound field set in operation S93a. Operations S92a and S93a may be related to operation S94a, subsequent thereto, in which data is transmitted, and accordingly, in the inventive concept, operations S92a, S93a, and S94a may be collectively referred to as an operation in which the originator <NUM> provides data to the recipient <NUM>.

The recipient <NUM> may extract the upper bound field from the data in operation S95a, and the recipient <NUM> may identify the upper bound of the block acknowledgement bitmap subfield length in operation S96a. For example, the recipient <NUM> may identify the upper bound of the block acknowledgement bitmap subfield length based on the value of the upper bound field extracted in operation S95a. Accordingly, the recipient <NUM> may directly identify the upper bound of the block acknowledgement bitmap subfield length based on the corresponding field.

In operation S97a, the recipient <NUM> transmits the block acknowledgement, and the originator <NUM> receives the block acknowledgement. The block acknowledgement may include the block acknowledgement bitmap subfield with the upper bound of the block acknowledgement bitmap subfield identified in operation S96a, i.e. a length equal to or less than the block acknowledgement bitmap subfield length limited in operation S92a. When the upper bound of the block acknowledgement bitmap subfield length is less than the maximum length of the block acknowledgement bitmap subfield lengths corresponding to the buffer size negotiated in operation S91a, the block acknowledgement is transmitted during the reduced duration.

Referring to <FIG>, the originator <NUM> and the recipient <NUM> negotiate the buffer size in operation S91b. For example, the originator <NUM> and the recipient <NUM> may negotiate the buffer size by transceiving each other a negotiation message.

In operation S92b, the originator <NUM> limits the block acknowledgement bitmap subfield length The originator <NUM> limits the length of the block acknowledgement bitmap subfield included in the block acknowledgement received in operation S97b corresponding to data transmitted in operation S94b to be described later. The originator <NUM> limits the block acknowledgement bitmap subfield length in various methods based on the size of data transmitted to the recipient <NUM>. The originator <NUM> reduces the duration by using the duration field included in the data, and accordingly, implicitly limits the length of the block acknowledgement bitmap subfield.

In operation S93b, the originator <NUM> may set the duration field. The originator <NUM> determines the duration for the block acknowledgement based on the block acknowledgement bitmap subfield length limited in operation S92b, and sets the duration field based on the determined duration.

In operation S94b, the originator <NUM> transmits data, and the recipient <NUM> receives data. For example, the originator <NUM> may transmit data including a plurality of MPDUs to the recipient <NUM>. In addition, data may include the duration field set in operation S93b. Operations S92b and S93b may be related to operation S94b, subsequent thereto, in which data is transmitted, and accordingly, in the inventive concept, operations S92b, S93b, and S94b may be collectively referred to as an operation in which the originator <NUM> provides data to the recipient <NUM>.

The recipient <NUM> may extract the duration field from the data in operation S95b, and the recipient <NUM> may identify the upper bound of the block acknowledgement bitmap subfield length in operation S96b. The recipient <NUM> identifies the reduced duration based on a value of the duration field extracted in operation S95b, and indirectly identifies the upper bound of the block acknowledgement bitmap subfield length based on the reduced duration.

In operation S97b, the recipient <NUM> transmits the block acknowledgement, and the originator <NUM> receives the block acknowledgement. The block acknowledgement may include the block acknowledgement bitmap subfield with the upper bound of the block acknowledgement bitmap subfield length identified in operation S96b, for example, a length equal to or less than the block acknowledgement bitmap subfield length limited in operation S92b. When the upper bound of the block acknowledgement bitmap subfield length is less than the maximum length of the block acknowledgement bitmap subfield lengths corresponding to the buffer size negotiated in operation S91b, the block acknowledgement is transmitted during the reduced duration.

<FIG> is a timing diagram of a block acknowledgement mechanism according to an example embodiment. As illustrated in <FIG>, the originator transmits data DATA, and the recipient transmits the block acknowledgement BA during the identified duration D based on the duration field included in the data DATA.

Referring to <FIG>, the data DATA transmitted to the recipient by the originator may include an upper bound field <NUM> representing the upper bound of the block acknowledgement bitmap subfield length. For example, the upper bound field <NUM>, as described above with reference to the table 80a of <FIG>, may have a length of <NUM> bits, or may have a length of <NUM> bits, as described above with reference to the table 80b of <FIG>. The recipient may extract the upper bound field <NUM> from the data DATA, and may identify the upper bound of the block acknowledgement bitmap subfield length based on the upper bound field <NUM>. When the identified upper bound of the block acknowledgement bitmap subfield length is less than the maximum length of the block acknowledgement bitmap subfield lengths corresponding to the negotiated buffer size, the recipient may transmit the block acknowledgement BA during the reduced duration D.

<FIG> and <FIG> are diagrams of examples of upper bound fields, according to example embodiments. As described above with reference to <FIG>, in some embodiments, the upper bound field may be included in data transmitted by the originator, and the recipient may identify the upper bound of the block acknowledgement bitmap subfield length based on the upper bound field (or the upper bound subfield) included in data.

Referring to <FIG>, the upper bound field may be included in a sequence control field <NUM>. For example, MAC frame <NUM> (for example, a data frame) described above with reference to <FIG> may include the sequence control field <NUM>. As illustrated in <FIG>, the sequence control field <NUM> may include a fragment number subfield and a sequence number subfield. The fragment number subfield may represent a fragment number that may be divided from an MAC service data unit (SDU) (MSDU), and a sequence number may represent the number of the MPDU. As illustrated in <FIG>, the fragment number subfield may have a length of <NUM> bits, and two bits (for example, B0 and B1) may be used for representing one of maximum four fragments. Accordingly, the remaining two bits (for example, B2 and B3) may be used as the upper bound field. In other words, the two bits (for example, B2 and B3) of the fragment number subfield may represent one of the block acknowledgement bitmap subfield lengths corresponding to the negotiated buffer size. For example, as illustrated in table <NUM> in <FIG>, a second bit B2 and a third bit B3 of the fragment number subfield may represent one of four block acknowledgement bitmap subfield lengths (for example, <NUM>, <NUM>, <NUM>, and <NUM>), when the negotiated buffer size is one of <NUM> through <NUM>. Accordingly, the recipient may identify the fragment number and the upper bound of the block acknowledgement bitmap subfield length based on the fragment number field.

Referring to <FIG>, the upper bound may be included in high throughput (HT) control field <NUM>. The HT control field <NUM> may have a plurality of variants, and the variant of the HT control field <NUM> may have a unique structure. As illustrated in <FIG>, the HT control field <NUM> may include an upper bound field, and the upper bound field may represent one of a plurality of block acknowledgement bitmap subfield lengths. Accordingly, the recipient may identify the upper bound of the block acknowledgement bitmap subfield length based on the upper bound field included in the HT control field <NUM>.

<FIG> is a diagram of examples of apparatuses for wireless communication, according to an example embodiment. <FIG> illustrates an Internet of Things (IoT) network system including home gadgets <NUM>, home appliances <NUM>, entertainment gadgets <NUM>, and an access point <NUM>.

Claim 1:
A first device (<NUM>, 71a, 71b, <NUM>) for wireless communication, the first device (<NUM>, 71a, 71b, <NUM>) comprising:
a transceiver (21_4); and
processing circuitry (21_1) configured to:
negotiate (S71a, S71b, S91a, S91b) a buffer size with a second device (<NUM>, 72a, 72b, <NUM>) via the transceiver (21_4), wherein a predetermined maximum block acknowledgement bitmap subfield length is associated corresponding to the range of the negotiated buffer size;
determine (S72a, S72b, S92a, S92b) an upper bound of the length of the block acknowledgement bitmap subfield based on a size of data to be transmitted, wherein the upper bound is equal to or less than the maximum block acknowledgement bitmap subfield length;
set (S73a, S73b, S93a, S93b) a duration field based on the determined upper bound, or a subfield defining the upper bound thereby explicitly limiting the block acknowledgement bitmap subfield length;
transmit (S74a, S74b, S94a, S94b) the data and including in the data at least one of the duration field (31_1) or the subfield to the second device (<NUM>, 72a, 72b, <NUM>) via the transceiver (21_4); and
receive (S76a, S76b, S97a, S97b) a first block acknowledgement from the second device (<NUM>, 72a, 72b, <NUM>) via the transceiver (21_4), the first block acknowledgement comprising a first block acknowledgement bitmap.