CN116614209A - HARQ and link adaptation in a wireless communication system - Google Patents

Abstract

An electronic device receives a first data unit including a first hybrid automatic repeat request (HARQ) unit and transmits a second data unit including first HARQ related information indicating that the first HARQ unit cannot be decoded. The electronic device receives a third data unit comprising a preamble. The preamble includes a first STF, a first LTF, a signal field, a second STF, and a second LTF, and the third data unit includes second HARQ-related information indicating whether the third data unit includes retransmitted data. The electronic device obtains a second HARQ unit based on determining that the second HARQ related information indicates that the third data unit includes retransmitted data, and decodes the second HARQ unit with the first HARQ unit.

Description

HARQ and link adaptation in a wireless communication system

Technical Field

The present disclosure relates to wireless communication systems, and more particularly, for example, but not limited to, hybrid automatic repeat request (HARQ) and link adaptation.

Background

Wireless communication devices are increasingly needed to support various delay-sensitive or real-time applications, such as Virtual Reality (VR), online gaming, augmented Reality (AR), robotics, artificial Intelligence (AI), cloud computing, and unmanned vehicles. To achieve the extremely low latency and extremely high throughput required for such applications, HARQ is considered to be one of the key technologies in the new revised standard ieee802.11be Extremely High Throughput (EHT) (also known as Wi-Fi 7). Conventional WLAN systems have used automatic repeat request (ARQ) procedures that rely solely on retransmission procedures in Medium Access Control (MAC) protocol data units (MPDUs). However, the MPDU cannot be used as a HARQ unit because the MPDU is a data unit in the MAC layer and performs a combining process in the HARQ process in the PHY layer.

The description set forth in the background section should not be assumed to be prior art because it is merely set forth in the background section. The background section may describe aspects or embodiments of the present disclosure.

Disclosure of Invention

Embodiments allow an electronic device to facilitate wireless communications supporting HARQ processes.

One aspect of the present disclosure provides an electronic device for facilitating wireless communication, the device comprising: one or more memories; and one or more processors coupled to the one or more memories, the one or more processors configured to cause: receiving a first data unit including a first Short Training Field (STF), a first Long Training Field (LTF), a signal field, a second STF, a second LTF, and a data field including a first hybrid automatic repeat request (HARQ) unit; transmitting a second data unit including first HARQ related information indicating that the first HARQ unit cannot be decoded; receiving a third data unit including a preamble, wherein the preamble includes a first STF, a first LTF, a signal field, a second STF, and a second LTF, and the third data unit includes second HARQ-related information indicating whether the third data unit includes retransmitted data; obtaining a second HARQ unit based on determining that the second HARQ related information indicates that the third data unit includes retransmitted data; and decoding the second HARQ unit by using the first HARQ unit.

The second HARQ related information may be included in a signal field of a preamble of the third data unit.

The signal field may comprise a user field comprising a first subfield indicating a station identifier and a second subfield indicating that the third data unit comprises retransmitted data.

The first data unit may include a MAC header including a link adaptation control subfield including a first MCS (modulation and coding scheme) request (MRQ) subfield and a first MRQ Sequence Identifier (MSI) subfield, the third data unit may include a MAC header including a link adaptation control subfield including a second MRQ subfield and a second MSI subfield, the second MSI subfield set equal to an MSI value that may be indicated by the first MSI subfield indicating that the third data unit includes retransmitted data, and the second MSI subfield set different from the MSI value indicated by the first MSI subfield may indicate that the third data unit does not include retransmitted data.

The second HARQ related information may be indicated by a bitmap comprising a plurality of bits, each of the plurality of bits being associated with a respective one of the HARQ units in the first data unit.

The second HARQ related information may be indicated by a field set equal to one of a plurality of states in a lookup table representing a respective one of the error combinations of HARQ units in the first data unit.

The scrambler seed for the second HARQ unit may be the same as the scrambler seed for the first HARQ unit.

Obtaining the second HARQ unit includes: receiving a fourth data unit following the third data unit, the fourth data unit comprising a first Short Training Field (STF), a first Long Training Field (LTF), a signal field, a second STF, and a second LTF, and a data field; and obtaining the second HARQ unit from the data field of the fourth data unit according to the parameters in the signal field in the fourth data unit.

The signal field of the third data unit may not include parameters for obtaining the second HARQ unit, and the second HARQ unit is obtained from one or more parameters in the signal field in the first data unit.

The first HARQ unit may be a low density parity check LDPC codeword including information bits and parity check bits.

The second HARQ unit may be a low density parity check LDPC codeword including information bits and parity check bits.

The second HARQ unit may be a low density parity check LDPC codeword including parity check bits and not including information bits.

The first HARQ unit may be a set of low density parity check, LDPC, codewords.

The first HARQ unit may be an MPDU.

The one or more processors may be configured to further cause: discarding the first HARQ unit if the third data unit comprises a HARQ unit not indicated by the first HARQ related information.

Another aspect of the present disclosure provides an electronic device for facilitating wireless communication, the device comprising: one or more memories; and one or more processors coupled to the one or more memories, the one or more processors configured to cause: transmitting a first data unit including a first Short Training Field (STF), a first Long Training Field (LTF), a signal field, a second STF, a second LTF, and a data field including a first hybrid automatic repeat request (HARQ) unit; receiving a second data unit comprising first HARQ related information indicating that the first HARQ unit failed to be decoded; and transmitting a third data unit including a preamble, wherein the preamble includes a first STF, a first LTF, a signal field, a second STF, and a second LTF, and the third data unit includes second HARQ-related information indicating whether the third data unit includes retransmitted data.

The second HARQ related information may be included in a signal field of a preamble of the third data unit.

The signal field may comprise a user field comprising a first subfield indicating a station identifier and a second subfield indicating that the third data unit comprises retransmitted data.

The first data unit may include a MAC header including a link adaptation control subfield including a first MCS modulation and coding scheme request, MRQ, subfield and a first MRQ sequence identifier, MSI, subfield, the third data unit may include a MAC header including a link adaptation control subfield including a second MRQ subfield and a second MSI subfield, the second MSI subfield set equal to an MSI value indicated by the first MSI subfield may indicate that the third data unit includes retransmitted data, and the second MSI subfield set different from the MSI value indicated by the first MSI subfield may indicate that the third data unit does not include retransmitted data.

Another aspect of the present disclosure provides a method performed by an electronic device, comprising: receiving a first data unit, wherein the first data unit comprises a first Short Training Field (STF), a first Long Training Field (LTF), a signal field, a second STF, a second LTF and a data field comprising a first hybrid automatic repeat request (HARQ) unit; transmitting a second data unit including first HARQ related information indicating that the first HARQ unit cannot be decoded; receiving a third data unit including a preamble, wherein the preamble includes a first STF, a first LTF, a signal field, a second STF, and a second LTF, and the third data unit includes second HARQ-related information indicating whether the third data unit includes retransmitted data; obtaining a second HARQ unit based on determining that the second HARQ related information indicates that the third data unit includes retransmitted data; and decoding the second HARQ unit by using the first HARQ unit.

Drawings

Fig. 1 shows a schematic diagram of an example wireless communication network.

Fig. 2 shows an example of a timing diagram of an inter-frame space (IFS) relationship between stations according to an embodiment.

Fig. 3 shows OFDM symbols and OFDMA symbols according to an embodiment.

Fig. 4A illustrates an EHT MU PPDU format according to an embodiment.

Fig. 4B illustrates an EHT TB PPDU format according to an embodiment.

Fig. 5 is a block diagram of an electronic device for facilitating wireless communications according to an embodiment.

Fig. 6 is a block diagram of a transmitter for transmission of a data field in an 80MHz PPDU according to an embodiment.

Fig. 7 is a block diagram of a transmitter for transmission of a data field in a 160MHz PPDU according to an embodiment.

Fig. 8 is a block diagram of a transmitter for transmission of a data field in a 320MHz PPDU according to an embodiment.

Fig. 9 shows a block diagram of a receiver according to an embodiment.

Fig. 10A illustrates a format of a MAC frame according to an embodiment.

Fig. 10B illustrates a format of an HT control field according to an embodiment.

Fig. 11 illustrates a format of an a control subfield of the HE variant HT control field according to an embodiment.

Fig. 12 shows a format of a control subfield of an a control subfield according to an embodiment.

Fig. 13 illustrates a format of a control information subfield among Link Adaptation (LA) control subfields according to an embodiment.

FIG. 14 illustrates a link adaptation process for a requesting MFB, according to an embodiment.

Fig. 15 illustrates a link adaptation process for an unsolicited MFB, in accordance with an embodiment.

Fig. 16 illustrates an a-MPDU format according to an embodiment.

Fig. 17 shows a structure of an a-MPDU sub-frame according to an embodiment.

Fig. 18 shows a structure of an EOF padding field according to an embodiment.

Fig. 19 shows a structure of an MPDU delimiter (relimiter) according to an embodiment.

Fig. 20 illustrates a general transmission procedure from MAC to PHY according to an embodiment.

Fig. 21 illustrates an a-MPDU format according to an embodiment.

Fig. 22 shows a HARQ process according to an embodiment.

Fig. 23 shows an initial HARQ unit and a retransmitted HARQ unit in an HARQ process according to an embodiment.

Fig. 24 shows an initial HARQ unit and a retransmitted HARQ unit in a HARQ process according to another embodiment.

Fig. 25 shows an initial HARQ unit and a retransmitted HARQ unit in a HARQ process according to another embodiment.

Fig. 26 shows an initial HARQ unit and a retransmitted HARQ unit in a HARQ process according to another embodiment.

Fig. 27 shows a HARQ unit in a HARQ process according to an embodiment.

Fig. 28 shows a HARQ process according to an embodiment.

Detailed Description

The detailed description set forth below is intended to describe various embodiments and is not intended to represent the only embodiments. As those skilled in the art will recognize, the described embodiments may be modified in various different ways, all without departing from the scope of the present disclosure. Accordingly, the drawings and description are to be regarded as illustrative in nature and not as restrictive. Like reference numerals designate like elements.

The following detailed description of the present invention is described with reference to a wireless LAN system in accordance with the Institute of Electrical and Electronics Engineers (IEEE) 802.11 wireless standard, including current and future modifications. However, one of ordinary skill in the art will readily recognize that the teachings herein are applicable to other network environments, such as cellular telecommunication networks and wired telecommunication networks.

In some embodiments, devices or apparatuses, such as AP STAs and non-APs, may include one or more hardware and software logic structures for performing one or more operations described herein. For example, an apparatus or device may include at least one memory unit storing instructions executable by a hardware processor installed in the apparatus and at least one processor configured to perform operations or processes described in the present disclosure. The apparatus may also include one or more other hardware or software elements, such as a network interface and a display device.

Fig. 1 shows a schematic diagram of an example wireless communication network.

Referring to fig. 1, a Basic Service Set (BSS) 10 may include a plurality of Stations (STAs) including an Access Point (AP) station (AP STA) 11 and one or more non-AP stations (non-AP STA) 12. STAs may share the same radio frequency channel through one of the WLAN operating bandwidth options (e.g., 20/40/80/160/320 MHz). Hereinafter, in some embodiments, an AP STA and a non-AP STA may be referred to as an AP and a STA, respectively. In some embodiments, an AP STA and a non-AP STA may be collectively referred to as a Station (STA).

Multiple STAs may participate in a multi-user (MU) transmission. In MU transmissions, the AP STA11 may simultaneously transmit downlink frames to the plurality of non-AP STAs 12 in the BSS 10 based on different resources, and the plurality of non-AP STAs 12 may simultaneously transmit uplink frames to the AP STAs 11 in the BSS 10 based on different resources.

For MU transmissions, multi-user multiple-input multiple-output (MU-MIMO) transmissions or Orthogonal Frequency Division Multiple Access (OFDMA) transmissions may be used. In MU-MIMO transmission, multiple non-AP STAs 12 may transmit simultaneously to the AP STA11 or receive separate data streams simultaneously from the AP STA11 on the same subcarrier using one or more antennas. Different frequency resources may be used as different resources in the MU-MIMO transmission. In OFDMA transmissions, multiple non-AP STAs 12 may transmit simultaneously to the AP STA11 or receive separate data streams simultaneously from the AP STA11 on different subcarrier groups. Different spatial streams may be used as different resources in MU-MIMO transmission.

Fig. 2 shows an example of a timing diagram of an inter-frame space (IFS) relationship between stations according to an embodiment.

Specifically, fig. 2 shows a CSMA (carrier sense multiple access)/CA (collision avoidance) -based frame transmission procedure for avoiding collision between frames in a channel.

Data frames, control frames, or management frames may be exchanged between STAs.

The data frame may be used for transmission of data forwarded to an upper layer. Referring to fig. 2, access is deferred while the medium is busy until one type of IFS duration has elapsed. The STA may transmit a data frame after performing backoff if a distributed coordination function IFS (DIFS) has elapsed since a time when the medium has been idle.

The management frame may be used to exchange management information that is not forwarded to an upper layer. Subtype frames of the management frame may include beacon frames, association request/response frames, probe request/response frames, and authentication request/response frames.

The control frame may be used to control access to the medium. Subtype frames of control frames include Request To Send (RTS) frames, clear To Send (CTS) frames, and Acknowledgement (ACK) frames. In the case where the control frame is not a response frame of another frame, if the DIFS has passed, the STA may transmit the control frame after performing backoff. If the control frame is a response frame of a previous frame, the WLAN device may transmit the control frame without performing backoff (backoff) if a Short IFS (SIFS) has elapsed. The type and subtype of a frame may be identified by a type field and a subtype field in a frame control field.

On the other hand, if an Arbitrated IFS (AIFS) (i.e., AIFS [ AC ]) of an Access Class (AC) has passed, a quality of service (QoS) STA may transmit a frame after performing backoff. In this case, a data frame, a management frame, or a control frame (not a response frame) may use AIFC [ AC ].

In some embodiments, an AP STA that enables a Point Coordination Function (PCF) may send a frame after performing a backoff if PCFIFS (PIFS) has passed. The PIFS duration may be less than DIFS but greater than SIFS.

Fig. 3 shows OFDM symbols and OFDMA symbols according to an embodiment.

For multi-user access modulation, orthogonal Frequency Division Multiple Access (OFDMA) for the uplink and downlink has been introduced in the ieee802.11ax standard known as High Efficiency (HE) WLAN and will be used in future modifications of 802.11 such as EHT (very high throughput). One or more STAs may be allowed to transmit data simultaneously using one or more Resource Units (RUs) throughout the operating bandwidth. One RU may be the smallest granularity that can be allocated and has tens of subcarriers in an OFDM modulation symbol. Here, the non-AP STA may or may not be associated with the AP STA when simultaneously responding in the allocated RU within a specific period such as a Short Inter Frame Space (SIFS). SIFS may be the time from the end of the last symbol of the previous frame or signal extension (if present) to the start of the first symbol of the preamble of the subsequent frame.

OFDMA is an OFDM-based multiple access scheme in which different subsets of subcarriers can be allocated to different users, allowing data transmission to or from one or more users simultaneously with highly accurate synchronization for frequency orthogonality. In OFDMA, users may be allocated different subsets of subcarriers that may change from one physical layer (PHY) protocol data unit (PPDU) to the next. In OFDMA, an OFDM symbol is composed of subcarriers, the number of which is a function of the PPDU bandwidth. The difference between OFDM and OFDMA is shown in fig. 3.

In the case of UL MU transmissions, an AP STA may want to have more control mechanism over the medium by using more scheduled accesses, which may allow more frequent use of OFDMA/MU-MIMO transmissions, given the different STAs with their own capabilities and features. The PPDU in UL MU transmissions (MU-MIMO or OFDMA) may be sent as a response to a trigger frame sent by the AP. The trigger frame may have information of the STA and allocate RU and a plurality of RUs (MRUs) to the STA. This allows the STA to transmit an OFDMA-based packet format with a TB PPDU (e.g., an HE TB PPDU or an EHT TB PPDU) segmented into RUs, and all RUs as a response to the trigger frame are allocated to the selected non-AP STA accordingly. Hereinafter, the single RU and the plurality of RUs may be referred to as RUs. The plurality of RUs may include or consist of two RUs predefined in combination.

In the EHT, two EHT PPDU formats are defined: EHT MU PPDU and EHT TB PPDU. Hereinafter, an EHT MU PPDU and an EHT TB PPDU will be described with reference to fig. 4A and 4B.

Fig. 4A illustrates an EHT MU PPDU format according to an embodiment.

The EHT MU PPDU may be used for both single user and multi-user transmissions.

Referring to fig. 4a, the EHT MU PPDU may include or consist of an EHT preamble (hereinafter, referred to as a PHY preamble or preamble), a data field, and a Packet Extension (PE) field. The EHT preamble may include or consist of a pre-EHT modulation field and an EHT modulation field. The pre-EHT modulation field may include or consist of a non-HT short training field (L-STF), a non-HT long training field (L-LTF), a non-HT signal (L-SIG) field, a repeated non-HT signal (RL-SIG) field, a universal signal (U-SIG) field, and an EHT signal (EHT-SIG) field. The EHT modulation field may include or consist of an EHT short training field (EHT-STF) and an EHT long training field (EHT-LTF). In some embodiments, the L-STF may be followed by an L-LTF, followed by an L-SIG field, followed by an RL-SIG field, followed by a U-SIG field, followed by an EHT-STF, followed by an EHT-LTF, followed by a data field, followed by a PE field.

The L-STF field may be used for packet detection (packet detection), automatic Gain Control (AGC), and coarse frequency offset correction.

The L-LTF field may be used for channel estimation, fine frequency offset correction, and symbol timing.

The L-SIG field may be used to transmit rate and length information.

The RL-SIG field may be a repetition of the L-SIG field and may be used to distinguish an EHT PPDU from a non-HT PPDU, an HT PPDU, and a VHT PPDU.

The U-SIG field may carry information necessary to interpret the EHT PPDU.

The EHT-SIG field may provide additional signaling to the U-SIG field for the STA to interpret the EHT MU PPDU. Hereinafter, the U-SIG field, the EHT-SIG field, or both may be referred to as a SIG field.

The EHT-SIG field may include one or more EHT-SIG content channels. Each of the one or more EHT-SIG content channels may include a common field and a user-specific field. The common field may contain information about the resource unit allocation, such as RU allocation to be used in the EHT modulation field of the PPDU, RU allocated for MU-MIMO, and the number of users in the MU-MIMO allocation. The user-specific fields may include one or more user fields.

The user fields for non-MU-MIMO allocation may include a STA-ID subfield, an MCS subfield, an NSS subfield, a beamforming subfield, and a coding subfield. The user fields for MU-MIMO allocation may include a STA-ID subfield, an MCS subfield, a coding subfield, and a spatial configuration subfield.

The EHT-STF field may be used to improve automatic gain control estimation in MIMO transmissions.

The EHT-LTF field may enable a receiver to estimate a MIMO channel between a set of constellation mapper outputs and a receive chain.

The data field may carry one or more Physical Layer Convergence Procedure (PLCP) service data units (PSDUs).

The PE field may provide additional receive processing time at the end of the EHT MU PPDU.

Fig. 4B illustrates an EHT TB PPDU format according to an embodiment.

Referring to fig. 4b, the EHT TB PPDU may include or consist of an EHT preamble (hereinafter, referred to as a PHY preamble or preamble), a data field, and a Packet Extension (PE) field. The EHT preamble may include or consist of a pre-EHT modulation field and an EHT modulation field. The pre-EHT modulation field may include or consist of a non-HT short training field (L-STF), a non-HT long training field (L-LTF), a non-HT signal (L-SIG) field, a repeated non-HT signal (RL-SIG) field, and a universal signal (U-SIG) field. The EHT modulation field may include or consist of an EHT short training field (EHT-STF) and an EHT long training field (EHT-LTF). In some embodiments, the L-STF may follow the L-LTF, follow the L-SIG field, follow the RL-SIG field, follow the U-SIG field, follow the EHT-STF, follow the EHT-LTF, follow the data field, follow the PE field.

A description for each field in the EHT TB PPDU will be omitted because the description for each field in the EHT MU PPDU is applicable to the EHT TB PPDU.

Hereinafter, EHT repeat transmission will be described.

In EHT repetition transmission (hereinafter, referred to as DUP transmission, frequency domain repetition, or DUP mode), data transmitted in a payload portion of a PPDU may be repeated in frequency. EHT repetition transmission may be applicable only to the 6GHz band in ieee802.11be (hereinafter, referred to as 11 be). The EHT duplicate transmission may be suitable for single user transmission in an EHT MU PPDU over a bandwidth of 80/160/320MHz without preamble penetration in 11 be. EHT repetition transmission may be applied in conjunction with BPSK-DCM modulation, rate-1/2 Low Density Parity Check (LDPC) coding, and one spatial stream in the data portion of the PPDU in 11 be. However, all limitations in 11be may not generally be limited to any particular feature, such as PPDU bandwidth, MCS (modulation and coding scheme) level, or number of spatial streams supporting DUP transmission.

The EHT DUP mode may be signaled by setting the PPDU type and compression mode subfield of the U-SIG field to 1 to indicate EHT transmissions to a single user, and setting the MCS field in the EHT-SIG field to 14.

For an 80MHz EHT MU PPDU transmitted in EHT DUP mode, the first 484-tone RU may be encoded and BPSK-DCM modulated and then copied along with partial symbol changes to the second (e.g., upper) 484-tone RU to reduce peak-to-average power ratio (PAPR).

For 160MHz EHT MU PPDUs transmitted in EHT DUP mode, the first 996-tone ru may be encoded and BPSK-DCM modulated, and then the first 996-tone ru may be copied to the second 996-tone ru along with partial symbol changes to reduce PAPR.

For 320MHz EHT MU PPDU transmitted in EHT-DUP mode, the first 2x996-toneRU may be encoded and BPSK-DCM modulated, and then the first 2x996-toneRU may be copied to the second 2x996-toneRU along with partial symbol changes to reduce PAPR.

Frequency domain replication occurs after LDPC tone mapping and segment reverse parsing operations.

An electronic device for facilitating wireless communications according to various embodiments will be described below with reference to fig. 5-9.

Fig. 5 is a block diagram of an electronic device for facilitating wireless communications according to an embodiment.

Referring to fig. 5, an electronic device 30 for facilitating wireless communication according to an embodiment may include a processor 31, a memory 32, a transceiver 33, and an antenna unit 34. The transceiver 33 may include a transmitter 100 and a receiver 200.

The processor 31 may perform MAC functions, PHY functions, RF functions, or a combination of some or all of the foregoing. In some embodiments, the processor 31 may include some or all of the transmitter 100 and the receiver 200. The processor 31 may be coupled directly or indirectly to the memory 32. In some embodiments, the processor 31 may include one or more processors.

The memory 32 may be a non-transitory computer-readable recording medium storing instructions that, when executed by the processor 31, cause the electronic device 30 to perform the operations, methods, or processes set forth in the present disclosure. In some embodiments, memory 32 may store instructions required by one or more of processor 31, transceiver 33, and other components of electronic device 30. The memory may also store an operating system and applications. The memory 32 may include, be implemented as, or be included in read-write memory, read-only memory, volatile memory, nonvolatile memory, or a combination of some or all of the foregoing.

The antenna unit 34 includes one or more physical antennas. When multiple-input multiple-output (MIMO) or multi-user MIMO (MU-MIMO) is used, the antenna unit 34 may include more than one physical antenna.

Fig. 6 is a block diagram of a transmitter for transmitting a data field in an 80MHz PPDU for an EHT-DUP mode according to an embodiment.

Referring to fig. 6, the transmitter 100 may include a front FEC (forward error correction) PHY filler 101, a scrambler 103, an LDPC encoder 105, a rear FECPHY filler 107, a stream parser 109, a constellation mapper 111, an LDPC tone mapper 113, a frequency domain replicator 115, a spatial mapper 117, N _TX Inverse Discrete Fourier Transformer (IDFT) 121, N _TX GI inserters 123 and N _TX DAC125。N _TX The number of transmit chains may be represented.

The pre-FEC PHY filler 101 may apply a pre-FEC PHY filler process to the information bits to output pre-FEC PHY filler bits.

The scrambler 103 may scramble the front FEC PHY pad bits based on the scrambler seed to output N _DBPS Scrambled bits. For example, for an 80MHz PPDU, N _DBPS May be 117.

LDPC encoder 105 may utilize N _DBPS Performing LDPC encoding with scrambled bits to generate N _CBPS LDPC coded bits. For example, for an 80MHz PPDU, N _CBPS May be 234.

An LDPC code is one of block codes having a parity check matrix, which contains only a very small number of non-zero elements. The parity check matrix is a matrix that explains the linear relationship of codeword components. Each row of the parity check matrix corresponds to a parity check equation and each column of the parity check matrix corresponds to a bit in the codeword. The biggest difference between LDPC codes and existing block codes is how they are decoded. Most existing block codes are decoded using a Maximum Likelihood (ML) decoding algorithm. ML-based approaches are typically short and algebraically designed to reduce complexity. However, LDPC codes are iteratively decoded using a graphical representation of their parity check matrix and are designed to focus on the properties of the parity check matrix.

To encode the LDPC PPDU, LDPC encoder 105 may calculate the number of bits N in the PSDU and SERVICE fields, for example, according to equation 1 below _pld Number of available bits N _avbits . In 11be, m _STBC May be 1 because 11be does not support STBC.

[ equation 1]

N _pld ＝length×8+16

Wherein, the liquid crystal display device comprises a liquid crystal display device,

m _STBC if STBC is used, 1, otherwise 1

Value of length field in length L-SIG field

N _pld Number of bits in PSDU and SERVICE fields

R coding rate

Then, the LDPC encoder 105 may calculate an integer number N of LDPC codewords to be transmitted _CW And the length L of LDPC codeword to be used _LDPC Table 1 below shows PPDU coding parameters.

TABLE 1

The post FEC PHY filler 107 may be configured to perform the following operations on N _CBPS The LDPC coded bits are applied to a post FEC PHY pad process to output post FEC PHY pad bits.

The stream parser 109 may parse the post FEC PHY-stuffed bits into N _SS Spatial flow. Since FIG. 6 shows a toolTransmitter with single spatial stream, thus N _SS May be 1.

The constellation mapper 111 may perform constellation mapping between bits of the spatial stream and complex constellation points to output complex samples. Constellation mapper 111 may perform Dual Carrier Modulation (DCM) to output a DCM encoded frequency domain signal. For example, if x represents the previous DCM frequency domain signal, the DCM encoded frequency domain signal y may be represented as the following equation 2.

[ equation 2]

y＝[x x _DCM ]

Wherein, the liquid crystal display device comprises a liquid crystal display device,and k= [0, ], N _SD -1]

The LDPC tone mapper 113 may perform LDPC tone mapping on the output of the stream parser 109 to output an LDPC tone mapped signal.

The frequency domain replicator 115 may perform frequency domain replication on the LDPC tone mapped signal to output a frequency domain replicated signal for EHT replication transmission. For example, when the EHT PPDU is encoded with the EHT-MCS 14, the frequency domain replicator 115 may perform frequency domain replication. According to an embodiment, the frequency domain replicator 115 may output a simple DUP frequency domain signal z= [ y y ]]Or the proposed replica frequency domain signal z= [ y-x x _DCM ]。

The spatial mapper 117 may perform spatial mapping on the output signal of the frequency domain replicator 115 to output N _TX N of the transmit chain _TX Spatially mapped signals.

N _TX An Inverse Discrete Fourier Transformer (IDFT) 121 may be coupled to N _TX A respective one of the transmit chains is associated. Each IDF 110 may perform an inverse discrete fourier transform on the spatial mapping signal to output OFDM symbols for the associated transmit chain.

N _TX A Guard Interval (GI) inserter 111 may be coupled to N _TX A respective one of the transmit chains is associated. N (N) _TX Each of GI inserter 123 may insert a GI into an OFDM symbol for an associated transmit chain.

N _TX Analog and RF unit112 can be equal to N _TX A respective one of the transmit chains is associated. N (N) _TX Each of the analog and RF units 112 may convert an OFDM symbol into an analog RF signal.

Fig. 7 is a block diagram of a transmitter for transmitting a data field in a 160MHz PPDU for an EHT-DUP mode according to an embodiment.

Referring to fig. 7, the transmitter 100 may include a front FEC PHY filler 101, a scrambler 103, an LDPC encoder 105, a rear FEC PHY filler 107, a stream parser 109, a constellation mapper 111, an LDPC tone mapper 113, a frequency domain replicator 115, a spatial mapper 117, N _TX Inverse Discrete Fourier Transformer (IDFT) 121, N _TX GI inserters 123 and N _TX DAC125。

A detailed description of the elements of the transmitter 100 shown in fig. 7 will be omitted because the detailed description of the elements of the transmitter 100 shown in fig. 6 may be applied to the detailed description of the elements of the transmitter 100 shown in fig. 7 except, for example, for the 160MHz PPDU N in fig. 7 _DBPS May be 245 and N _CBPS Some exceptions to 490 may be made.

Fig. 8 is a block diagram of a transmitter for transmitting a data field in a 320MHz PPDU for an EHT-DUP mode according to an embodiment.

Referring to fig. 8, a transmitter 100 may include a front FECPHY filler 101, a scrambler 103, an LDPC encoder 105, a rear FECPHY filler 107, a stream parser 109, a segment parser 110, a plurality of constellation mappers 111, a plurality of LDPC tone mappers 113, a segment inverse parser 114, a frequency domain replicator 115, a spatial mapper 117, N _TX Inverse Discrete Fourier Transformer (IDFT) 121, N _TX GI inserters 123 and N _TX DAC 125。

A detailed description of some elements of the transmitter 100 shown in fig. 8 will be omitted because the detailed description of the elements of the transmitter 100 shown in fig. 6 may be applicable to the detailed description of some elements of the transmitter 100 shown in fig. 8. For example, in fig. 8, for 320mhz ppdu, n _DBPS May be 490, and N _CBPS 980 may be.

The segment parser 110 may divide the output of the stream parser 109 into a lower frequency sub-block and an upper frequency sub-block.

In some embodiments, the plurality of constellation mappers 111 may include a lower constellation mapper and an upper constellation mapper.

The lower constellation mapper may perform constellation mapping between bits of the lower frequency sub-block and complex constellation points to form a lower N _SD And/2, outputting complex samples of the sub-blocks of the lower frequency on the sub-carrier. The lower constellation mapper may perform Dual Carrier Modulation (DCM) to output a frequency domain signal for DCM encoding of the lower frequency sub-block. For example, if X _L Representing the previous DCM frequency domain signal for the lower frequency sub-block, then the DCM encoded frequency domain signal y for the lower frequency sub-block _L As can be represented in equation 3 below.

[ equation 3]

y _L ＝[x _L x _L，DCM ]

Wherein, the liquid crystal display device comprises a liquid crystal display device,and->

The upper constellation mapper may perform constellation mapping between bits of the upper frequency sub-block and complex constellation points to form an upper N _SD And/2, outputting the complex sample of the upper frequency sub-block on the sub-carrier. The upper constellation mapper may perform Dual Carrier Modulation (DCM) to output a frequency domain signal for DCM encoding of the upper frequency sub-block. For example, if x _U Representing the previous DCM frequency domain signal for the upper frequency sub-block, then the DCM encoded frequency domain signal y for the upper frequency sub-block _U As can be represented in equation 4 below.

[ equation 4]

y _U ＝[x _U x _U，DCM ]

Wherein, the liquid crystal display device comprises a liquid crystal display device,and->

In some embodiments, the plurality of LDPC tone mappers 113 may include a lower LDPC tone mapper and an upper LDPC tone mapper.

The lower LDPC tone mapper may perform LDPC tone mapping on an output of the lower constellation mapper to output an LDPC tone mapped signal of the lower frequency sub-block.

The upper LDPC tone mapper may perform LDPC tone mapping on an output of the upper constellation mapper to output an LDPC tone mapped signal of the upper frequency sub-block.

The segment inverse parser 114 may merge the two frequency sub-blocks into one frequency segment.

The frequency domain replicator 115 may perform frequency domain replication on the output of the segment inverse parser 114 to output a frequency domain replica signal for EHT replica transmission. For example, when the EHT PPDU is encoded with the EHT-MCS14, the frequency domain replicator 115 may perform frequency domain replication. According to an embodiment, the frequency domain replicator 115 may output a simple DUP frequency domain signal z= [ y y ] ]Or proposed replica frequency domain signal z= [ y-x ] _L -x _L，DCM x _U x _U，DCM ]。

Table 2 below provides parameters related to the pad of the EHT-MCS 14 for the EHT DUP mode, and N _SS,u ＝1。N _SS,u Representing the number of spatial streams for user u.

TABLE 2

In Table 2, ru represents the coding rate of user u, N _BPSCS,u Representing the number of coded bits per subcarrier per spatial stream for user u, N _SD,u Representing the effective number of data tones carrying unique data for user u, N _CBPS,u Representing the number of coded bits per OFDM symbol for user u, N _DBPS,u Representing the number of data bits per OFDM symbol for user u.

The EHT-STF, EHT-LTF and pilot subcarriers for the 80MHz EHT MU PPDU transmitted in the EHT DUP mode may be constructed in the same manner as those EHT MU PPDUs transmitted in the OFDMA format with the two 484-tone RUs occupied. The EHT-STF, EHT-LTF, and pilot subcarriers for a 160/320MHz EHT MU PPDU transmitted in the EHT DUP mode may be constructed in the same manner as a 160/320MHz EHT MU PPDU transmitted in a non-OFDMA format.

Fig. 9 shows a block diagram of a receiver according to an embodiment.

Referring to fig. 9, a receiver 200 according to an embodiment may include an RF receiver 201, a GI remover 203, a Fourier Transformer (FT) 205, a demapper 207, a deinterleaver 209, and a decoder 211.

RF receiver 201 may receive RF signals via antenna element 34 and convert the RF signals to one or more symbols.

GI remover 203 may remove the GI from the symbol.

According to an embodiment, FT 205 may convert symbols corresponding to a time domain block into a block of constellation points by using a Discrete Fourier Transform (DFT) or a Fast Fourier Transform (FFT).

The demapper 207 may demap blocks of constellation points to demapped data bits. If LDPC encoding is used, the demapper 207 may also perform LDPC tone demapping before constellation demapping.

The deinterleaver 209 may deinterleave the demapped data bits to generate deinterleaved data bits. In some embodiments, when BCC coding is used, deinterleaving may be applied.

Decoder 211 may decode the deinterleaved data bits to generate decoded bits. For example, the decoder 211 may be an FEC decoder. The FEC decoder may comprise a BCC decoder or an LDPC decoder. To support HARQ processes, the decoder 211 may combine the retransmitted data with the initial data.

The descrambler 213 may descramble the descrambled data bits based on the scrambler seed.

Link Adaptation (LA) parameters for a WLAN system may be sent as part of a MAC header. The parameters may be carried in the HT control field in the MAC header. Hereinafter, the format of the MAC frame will be described with reference to fig. 10A, 10B, 11, 12, and 13.

Fig. 10A illustrates a format of a MAC frame according to an embodiment.

Referring to fig. 10a, a MAC frame may include a MAC header, a frame body, and an FCS. The MAC header may include a frame control field, a duration/ID field, an address 1 field, an address 2 field, an address 3 field, a sequence control field, an address 4 field, a QoS control field, an HT control field.

Fig. 10B illustrates a format of an HT control field according to an embodiment.

Referring to fig. 10B, a B0 bit of the HT control field may be set to 0 to indicate that the HT control field is an HT variant HT control field including an HT control intermediate subfield, an AC constraint subfield, and an RDG/more PPDU subfield. The B0 and B1 bits of the HT control field may be set to 1 and 0 to indicate that the HT control field is a VHT variant HT control field including a VHT control intermediate subfield, an AC constraint subfield, and an RDG/more PPDU subfield. The B0 and B1 bits of the HT Control field may be set to 1 and 1 to indicate that the HT Control field is a HE variant HT Control field including an a-Control subfield. The AC constraint subfield of the HT control field may indicate whether the mapped Access Class (AC) of the RD (reverse direct) data frame is limited to a single AC. The RDG/more PPDU subfield of the HT control field is interpreted differently depending on whether it is transmitted by the RD initiator or the RD responder.

Fig. 11 illustrates a format of an a-Control subfield of the HE variant HT Control field according to an embodiment.

Referring to fig. 11, an a-Control subfield of the he variant HT Control field may include a Control list subfield and padding bits. The a control subfield length may be fixed 30 bits. The control list subfield may have a variable number of bits. The control list subfield contains one or more control subfields. The format of each control subfield is shown in fig. 12.

Fig. 12 shows a format of a Control subfield of an a-Control subfield according to an embodiment.

Referring to fig. 12, the Control subfield of the a-Control subfield may include a Control ID subfield and a Control information subfield.

The control ID subfield may indicate the type of information carried in the control information subfield. The length of the control information subfield may be fixed for each value of the control ID subfield. The value of the control ID subfield and the associated length of the control information subfield may be defined in table 3.

TABLE 3

Control ID value	Meaning of	Length (bits) of control information subfield
			0	Triggered Response Scheduling (TRS)	26
1	Operation Mode (OM)	12
			2	HE Link Adaptation (HLA)	26
3	Buffer Status Report (BSR)	26
			4	UL Power Headroom (UPH)	8
5	Bandwidth Query Report (BQR)	10
			6	Command and status (CAS)	8
7	EHT mode of operation (EHT OM)	6
			8	Single Response Scheduling (SRS)	10
10	AP Assist Request (AAR)	20
			9,11-14	Reservation of
15	People determine that expansion is needed (ONES)	26

As shown in table 3, for example, the control ID subfield is set to 2 to indicate that the control subfield is a HE Link Adaptation (HLA) control subfield of the control information subfield, which includes carrying information related to the HE Link Adaptation (HLA) process.

In some embodiments, the control ID subfield is set to one of the reserved values (9, 11-14) in table 3 to indicate that the control subfield is a proposed link adaptation control subfield comprising a control information subfield carrying information related to a proposed link adaptation (HLA) process, which may be referred to as EHT link adaptation. The control information subfield length in the proposed link adaptation control subfield may be 26 bits. The format of the control information subfield of the proposed link adaptation control subfield is shown in fig. 13.

Fig. 13 illustrates a format of a control information subfield among Link Adaptation (LA) control subfields according to an embodiment.

Referring to fig. 13, the control information subfield in the proposed Link Adaptation (LA) subfield may include an unsolicited MCS Feedback (MFB) subfield, an MCS Request (MRQ) subfield, an NSS subfield, an MCS subfield, a PS160 subfield, an RU allocation subfield, a BW subfield, an MSI/partial PPDU parameter subfield, a Tx beamforming subfield, an UL TB PPDU MFB subfield, and a BW extension subfield as information related to the link adaptation procedure.

The length of the unsolicited MCS Feedback (MFB) subfield, MCS Request (MRQ) subfield, NSS subfield, MCS subfield, PS 160 subfield, RU allocated subfield, BW subfield, MSI/partial PPDU parameter subfield, tx beamforming subfield, UL TB PPDU MFB subfield, and BW extended subfield may be, but are not limited to, 1, 3, 4, 1, 8, 2, 3, 1, and 1 bits, respectively.

The unsolicited MFB subfield may indicate whether LA control is an unsolicited MFB. For example, if the LA control is an unsolicited MFB, the unsolicited MFB subfield may be set to 1, and if the LA control is an MRQ or a solicited MFB, the unsolicited MFB subfield may be set to 0.

The MRQ subfield may be used to request LA feedback. For example, in the LA control subfield of a frame requesting link adaptation feedback, the MRQ subfield may be set to 1 and the MFB subfield not requested may be set to 0. The MRQ subfield may be set to 0 and the unsolicited MFB subfield may be set to 0 in response to the LA request.

The NSS subfield may indicate a recommended number of spatial streams.

The MCS subfield may indicate a recommended MCS. In some embodiments, DCM may be indicated with MCS 15. In some embodiments, the available MCS 14 indicates the DUP mode.

The RU allocation subfield may indicate an RU to which the recommended MCS is applied. The recommended RU may be within the bandwidth where the RU or the received PPDU is located. The RU allocation subfield may indicate the RU of the recommended MCS/RU specified by the MFB requester to obtain feedback.

The format of the LA control subfield may contain information for RU allocation and channel bandwidth information for reflecting a plurality of RUs and RU sizes. For example, to identify the size and location of the RU or MRU, first control information may be introduced over the RU allocation subfield. The first control information and the RU-allocation subfield may be jointly encoded, wherein the first bit of the first control information and the RU-allocation subfield may indicate which 80MHz sub-block is located according to a bandwidth or RU/MRU size. The first control information may indicate which 160MHz segment location according to bandwidth and RU/MRU size. In some embodiments, the B0 bit of the RU allocation subfield may be set to 0 to indicate that the RU or MRU allocation applies to the primary 80MHz channel and to 1 to indicate that the RU allocation applies to the secondary 80MHz channel in the primary 160 MHz. In some embodiments, the B0 bit of the RU allocation subfield may be set to 0 to indicate that RU or MRU allocation applies to the lower 80MHz of the secondary 160MHz and may be set to 1 to indicate that RU allocation applies to the upper 80MHz of the secondary 160 MHz.

The PS160 subfield may indicate first control information. For example, the second control information may be a BW extension subfield, jointly encoded with BW to indicate 20, 40, 80, 160, and 320MHz.

The BW subfield may be the bandwidth of the recommended MCS/bandwidth specified by the MFB requester to obtain feedback. The BW subfield may indicate a BANDWIDTH less than or equal to the BANDWIDTH indicated by the parameter ch_bandwidth.

The UL TB PPDU MFB subfield may indicate that the NSS subfield, the MCS subfield, the BW subfield, the RU allocated field represent a recommended MFB for the TB PPDU in response.

The MSI/partial PPDU parameter subfield may indicate a partial parameter or MRQ Sequence Identifier (MSI) of the measured PPDU. For example, if the unsolicited MFB subfield is 0 and the MRQ subfield is 1, the MSI/partial PPDU parameter subfield may contain a sequence number in the range of 0 to 6, which identifies the particular link adaptation feedback request. The MFB responder sending the requested MFB should set the unsolicited MFB subfield to 0 and the MRQ subfield to 0 in the LA control subfield. If the unsolicited MFB subfield is 1, the MSI/partial PPDU parameter subfield may contain a PPDU type as well as a compressed mode subfield and a coding type subfield. The coding type subfield may indicate whether the PPDU is BCC coded or LDPC coded. The CODING type subfield may be set to 0 if the parameter fec_coding is equal to bcc_coding, and may be set to 1 if the parameter is equal to ldpc_coding. Instead of the coding type subfield, the UL/DL subfield may be included in the MSI/partial PPDU parameter subfield. The PPDU type and compressed mode fields may be encoded in conjunction with UL/DL subfields to indicate PPDU types such as DL OFDMA (including non-MU-MIMO and MU-MIMO), DL transmissions to a single user or NDP, DL MU-MIMO (non-OFDMA), UL OFDMA or UL non-OFDMA (including non-MU-MIMO and MU-MIMO), and UL transmissions to a single user or NDP, as shown in table 4 below.

TABLE 4

The Tx beamforming subfield may be set to 1 if the parameter BEAMFORMED is equal to 1, and to 0 if the parameter is equal to 0.

In 802.11 Link Adaptation (LA) systems, there are basically two Feedback (FB) types, requested FB and unsolicited FB. Hereinafter, a link adaptation process will be described with reference to fig. 14 and 15.

FIG. 14 illustrates a link adaptation process for a requesting MFB, according to an embodiment.

At S51, the electronic device 300 acting as an MFB requester may transmit a first PPDU containing a LA control subfield indicating an MFB request for requesting MCS feedback.

In some embodiments, in the LA control subfield of the first PPDU, the MRQ subfield may be set to 1 and the unsolicited MFB subfield may be set to 0 to transmit MFB requests in the first PPDU. In each MFB request, the MFB request may set the MSI/partial PPDU parameter subfield to a value ranging from 0 to 6 as the MRQ sequence identifier. In some embodiments, how the MSI value is selected may depend on the implementation.

At S52, the electronic device 400 acting as the MFB responder may calculate MFB parameters, such as recommended MCS, recommended NSS, and recommended DCM for RU and BW specified in the MFB request, based on the same RU of the first PPDU carrying the MFB request. The electronic device 400 may calculate MFB parameters indicating the MFB request from the frame LA control subfield.

At S53, the electronic device 400 may transmit a second PPDU containing a LA control subfield indicating a requested MCS feedback including the calculated MFB parameters. In some embodiments, in the LA control subfield of the second PPUD, both the MRQ subfield and the unsolicited MFB subfield may be set to 0 to indicate MFB, the MCS subfield may indicate recommended MCS and recommended DCM, and the NSS subfield may indicate recommended NSS.

In some embodiments, the MRQ sequence identifier indicated by the MSI/partial PPDU parameter subfield of the LA control subfield of the second PPUD may be set equal to the value of the MRQ sequence identifier indicated by the MSI/partial PPDU parameter subfield of the LA control subfield of the first PPUD.

In some embodiments, the occurrence of more than one instance of the LA control subfield with an MRQ field equal to 1 within a single PPDU may be interpreted by the electronic device 400 as a single request for link adaptation feedback. The electronic device 300 may specify RU/MRU (e.g., RU subfield and PS160 subfield) and BW (e.g., BW subfield and BW extension subfield) that request link adaptation feedback. Upon receiving the LA control subfield with an MRQ subfield equal to 1, the receiver may calculate the MCS and NSS for the RU/MRU and BW specified in the MRQ, and these estimates may be based on the same RU/MRU of the PPDU carrying the MRQ. The PPDU carrying the MRQ may include RU/MRU requested for MFB. The electronic device 400 may tag the result of this calculation with the MSI value from the LA control subfield in the received frame carrying the MRQ. The electronic device 400 may include the received MSI value in the MSI field of the corresponding response frame. In the case of a delayed response, this allows the electronic device 300 to associate the MFB with the request MRQ. PPDUs bearing different MSIs associated with the same STA may be transmitted between PPDUs bearing the same MSI in the preamble or LA control subfield.

In some embodiments, for a requested or unsolicited response, recommended MCS and NSS subfields for the LA control subfield may be selected from a set of MCSs and NSSs supported by the recipient STA.

In some embodiments, the MCS subfield of the HLA control subfield may be a recommended data rate for a given transmission attribute carried in RXVECTOR for a PPDU for MFB estimation, resulting in an estimated frame error rate of 10% or less for MPDU lengths of 3895 octets.

In some embodiments, if the MFB requestor sets the MRQ subfield to 1 and the MSI subfield to a value that matches the MSI subfield value of a previous request that the responder has not provided feedback, the responder may discard or discard the calculation of the MRQ corresponding to the previous use of the MSI subfield value and begin a new calculation based on the new request.

In some embodiments, the STA may immediately respond to the current request of the MFB with a frame containing the MSI field value and NSS, and an MCS subfield corresponding to the request preceding the current request.

In some embodiments, the non-AP STA may set the UL TB PPDU MFB to 1 in the LA control field it sends to the AP to indicate NSS, MCS, BW and RU allocation in the LA control field to indicate the recommended MFB of the TB PPDU sent from the non-AP STA. When the AP transmits a trigger frame addressed to the STA, the AP may not exceed the recommended RU size indicated in the recently received RU allocation field of the LA control field.

In some embodiments, the combination of the MCS subfield and the NSS subfield may indicate whether the electronic device 400 is providing feedback for a request having an MSI value indicated by the MSI subfield.

In some embodiments, electronic device 400 may set the MCS subfield, NSS subfield, and MSI subfield to predetermined values to indicate that electronic device 400 will not provide feedback for a request having an MSI value indicated by the MSI subfield. In some embodiments, one or more predetermined combinations of MCS, NSS, and MSI may be used. For example, when MCS, NSS, and MSI are equal to A, B and 0-N, respectively, it may indicate that electronic device 400 will not provide feedback for a request with the MSI value. N may depend on the size of the MSI subfield. For example, the value a may be 14, which is used to indicate the frequency copy mode (DUP mode) of other control fields in the PHY or MAC. MCS 14 in the LA control subfield may indicate that when DUP mode is inactive for link adaptation or HARQ, electronic device 400 will not provide feedback for requests with MSI values. For example, B may be 7. When B is 0 to 6, it may indicate a predefined NSS.

In some embodiments, electronic device 400 may set the MCS subfield, NSS subfield, and MSI subfield to values that indicate that electronic device 400 is providing feedback for a request having an MSI value. For example, when MCS and NSS are set equal to a valid value and MSI is set equal to 0-N, it may indicate that electronic device 400 is providing feedback for a request having that MSI value. The MSI value in the response frame matches the MSI value of the MRQ request. N may depend on the size of the MSI subfield.

In some embodiments, an invalid combination of the BW subfield and the extended BW subfield may be used to indicate that the electronic device 400 will not provide feedback for a request with an MSI value indicated by the MSI subfield.

Assuming that all values of the allowed MCS in the MCS subfield are used to indicate different MCSs and that the number of NSSs requires more states to indicate up to 16 spatial streams, other subfields need to be used to indicate this. In some embodiments, instead of MCS or NSS, an invalid combination of RU/MRU indication and MSI may be used to indicate that electronic device 400 will not provide feedback for requests having an MSI value indicated by the MSI subfield. For example, indicated by one of the following reservation states.

TABLE 5

Table 5 shows the encoding of PS160 and RU allocation subfields in the EHT variant user information field according to an embodiment. As shown in table 5, if the state indicated by the B1 to B7 bits of the RU allocated subfield is any one between 107 and 127, it may indicate that electronic device 400 will not provide feedback for a request having an MSI value indicated by the MSI subfield.

At S54, the electronic device 300 may calculate TXVECTOR parameters, such as appropriate MCS, DCM, and NSS, based on the received MFB parameters.

At S55, the electronic device 300 may transmit a third PPDU based on the calculated transmission parameters.

In some embodiments, the same MSI value may be carried when the preamble of the third PPDU includes identification information associated with the HARQ process. For example, when the electronic device 400 fails to decode the HARQ units in the first PPDU and the third PPDU, the MSI indicated by the MSI/partial PPDU parameter subfield in the third PPDU may be equal to the MSI indicated by the MSI/partial PPDU parameter subfield in the first PPDU.

Fig. 15 illustrates a link adaptation process for an unsolicited MFB, in accordance with an embodiment.

At S61, the electronic device 300 may transmit the first PPDU without any MFB request.

At S62, the electronic device 400 may determine whether to transmit an unsolicited MFB. It may be entirely a selection of electronic device 400.

At S63, when the electronic device 400 determines to transmit an unsolicited MFB, the electronic device 400 may calculate MFB parameters such as a recommended MCS, a recommended NSS, a recommended DCM, a recommended BW, and a recommended RU. Unsolicited MCS, NSS, DCM, BW and RU estimates to be reported in the LA control subfield sent by the electronic device 400 may be calculated based on the most recent PPDUs received by the electronic device 400 that match the description indicated by the PPDU format, tx beamforming, and coding type subfields in the same control subfield.

At S64, the electronic device 400 may transmit a second PPDU containing a LA control subfield, the second PPDU indicating unsolicited MCS feedback including the calculated MFB parameters. For example, in the LA control subfield of the second PPDU, the unsolicited MFB subfield may be set to 1 to indicate unsolicited MFB, the MCS subfield may indicate recommended MCS and recommended DCM, the NSS subfield may indicate recommended NSS, the RU allocation subfield may indicate recommended RU, and the BW subfield may indicate recommended bandwidth. The parameters indicated by the MSI/partial PPDU parameter subfield and Tx beamforming subfield of the LA control subfield of the second PPDU (e.g., PPDU format, coding type, and Tx beamforming) may be set to match the RXVECTOR parameters of the first PPUD on which the electronic device 400 calculates unsolicited MFB parameters. The second PPDU may carry those parameters because the electronic device 300 does not have an MSI to identify the PPDUs that the electronic device 400 measures to calculate the MFB parameters. As shown in table 4, PPDU format subfields indicating the PPDU format may be set and encoded.

At S65, the electronic device 300 may calculate TXVECTOR parameters, such as appropriate MCS, DCM, NSS, RU and BW, based on the received MFB parameters.

At S66, the electronic device 300 may transmit a third PPDU based on the calculated transmission parameters.

Hereinafter, HARQ processes according to various embodiments will be described with reference to fig. 16 to 28.

New modifications in WLANs have decided to support hybrid automatic repeat request (HARQ) due to the requirements for increased reliability and reduced delay. So far, in 11ax, WLAN systems use a conventional automatic repeat request (ARQ) process that relies only on MPDU unit-wise retransmission procedures when the transmitter does not receive an acknowledgement from the receiver. In this conventional automatic repeat request (ARQ) method, when a receiver fails to decode MPDUs, it discards those MPDUs before receiving a new retransmitted MPDU.

For HARQ units to be considered, a-MPDUs and LDPC codewords will be described with reference to fig. 16 to 21.

Fig. 16 illustrates an a-MPDU format according to an embodiment.

Referring to fig. 16, an a-MPDU may include or consist of a sequence of one or more a-MPDU subframes and EOF padding subframe subfields. The EOF padding subframe subfield may include a variable number of EOF padding.

Fig. 17 shows a structure of an a-MPDU sub-frame according to an embodiment.

Referring to fig. 17, each a-MPDU sub-frame may include, or consist of, an MPDU delimiter, optionally followed by an MPDU. Each non-final a-MPDU subframe may contain up to 3 bytes of padding octets that are appended to the end of the a-MPDU subframe such that the length of the a-MPDU subframe is a multiple of 4 octets. The contents of these octets may be unspecified.

Fig. 18 shows a structure of an EOF padding field according to an embodiment.

Referring to fig. 18, the EOF padding subframe subfield may include or consist of zero or more EOF padding subframes. The EOF padding subframe is an a-MPDU subframe of the MPDU delimiter shown in fig. 19, with 0 in the MPDU length field and 1 in the EOF field.

Fig. 19 illustrates a structure of an MPDU delimiter according to an embodiment.

Referring to fig. 19, the MPDU delimiter according to an embodiment may be 4 octets in length and may include or consist of an EOF field, a reserved field, a MPDU length field, a CRC field, and a delimiter signature field. The CRC field may be used as a Frame Check Sequence (FCS) to protect the reserved field and the MPDU length field. The size and description of the fields of the MPDU delimiter are shown in table 6 below.

TABLE 6

Fig. 20 illustrates a general transmission procedure from MAC to PHY according to an embodiment.

Referring to fig. 20, the mac entity may generate an a-MPDU including a plurality of a-MPDU sub-frames and transmit the a-MPDU to the PHY entity.

The PHY entity may generate a PSDU including a service field, an a-MPDU, and a pre-FEC filler.

The PHY entity may then scramble the PSDU to generate scrambled data.

The PHY entity may encode the scrambled data to generate encoded data comprising a plurality of LDPC codewords.

As shown in fig. 20, there is no specific mapping rule between MPDUs and LDPC codewords, because PHY entities do not need to know MPDUs and MAC entities do not need to know LDPC codewords. Even though the PHY entity and the MAC entity do not know how MPDUs are mapped to CW, there is no problem because MPDUs are operation units only for MAC entities and LDPC codewords are operation units only for PHY entities.

In order for the WLAN to support HARQ, a new method for aligning the initial LDPC codeword and the retransmission codeword may be introduced. HARQ operations are basically operated by the PHY layer to combine retransmitted data into initially transmitted data to improve decoding performance. This misalignment of the CW in the retransmitted MPDUs may make the combining process infeasible.

Fig. 21 illustrates an a-MPDU format according to an embodiment.

As shown in fig. 21, the MPDU may include an MPDU header, ext-IV, ciphertext, MIC, and CRC. When the HARQ process is MPDU level based, parameters in the MPDU (such as MPDU header, ext-IV, ciphertext, MIC, and CRC) may potentially not match between the original MPDU and the retransmitted MPDU. If the retransmitted MPDUs carry different parameters than the original MPDUs, these changed parameters may result in different payloads at PHY level, and the PHY entity is not aware of the changes during the original transmission and the retransmission in the HARQ process. Such misalignment may make it impossible to perform log-likelihood ratio (LLR) combining on retransmitted MPDUs directly at the PHY level.

Fig. 22 shows a HARQ process according to an embodiment.

Referring to fig. 22, at S110, the electronic device 300 may transmit a data unit PPDU1 to the electronic device 400. In some embodiments, the data unit PPDU1 may include a plurality of HARQ units. In some embodiments, each of the plurality of HARQ units may be an LDPC codeword. In some embodiments, each of the plurality of HARQ units may be a set of one or more LDPC codewords. In some embodiments, each of the plurality of HARQ units may be an MPDU. In some embodiments, each of the plurality of HARQ units may be a set of one or more MPDUs. In some embodiments, each of the plurality of HARQ units may be a newly defined unit other than an LDPC codeword and MPDU.

At S120, the electronic device 400 may detect which HARQ unit has not been successfully decoded. The electronic device 400 may store HARQ units that have not been successfully decoded.

At S130, the electronic device 400 may transmit a data unit PPDU2 to the electronic device 400 in response to the data unit PPDU1. In some embodiments, the data unit PPDU2 may include HARQ related information indicating which HARQ unit fails decoding. The HARQ related information in the data unit PPDU2 may be referred to as HARQ feedback information.

In some embodiments, HARQ related information may be carried in a MAC frame of the data unit PPDU 2.

In some embodiments, HARQ related information may be carried in the PHY preamble of the data unit PPDU 2.

At S140, the electronic device 300 may transmit a data unit PPDU3 to the electronic device 400 in response to the data unit PPDU 2. The data unit PPDU3 may include zero or more HARQ units. In some embodiments, the data unit PPDU3 may include HARQ related information. In some embodiments, the PHY preamble of the data unit PPDU3 may include a portion of HARQ related information or compressed information of HARQ related information because of a potential delay between transmission and retransmission. In some embodiments, the HARQ related information field may include identification information for indicating whether the data unit PPDU3 contains one or more retransmitted HARQ units, control information for indicating which HARQ unit(s) to retransmit in the data unit PPDU3, or both.

In some embodiments, the scrambler seed used to scramble data unit PPDU3 may be equal to the scrambler seed used to scramble data unit PPDU 1. For example, if the same identity is explicitly carried in the preambles of data unit PPDU1 and data unit PPDU3, the same scrambler seed in the first transmitted data unit PPDU1 may be reused as the scrambler seed of data unit PPDU 3. For example, the identification may be used as a scrambler seed.

Another approach refers to user specific information as an implicit way. In some embodiments, a portion of the STA-ID may be used for the scrambler seed. In some embodiments, MSI may be used for the scrambler seed because its value may be the same for the same data information.

In some embodiments, the identification information field may be included in a preamble portion of the PPDU depending on the sequence associated with the HARQ process. For example, the identification information field may be included in a preamble portion of the data unit PPDU 3.

In some embodiments, the identification information field may be included in the MAC portion of the PPDU depending on the sequence associated with the HARQ process. For example, the identification information field may be included in a MAC frame of the data unit PPDU 3.

In some embodiments, the value of the identification information field may be an integer ranging from 0 to 2N-1, where N is the size of the field containing the identification information. It maintains the same value to indicate the HARQ unit retransmitted for the first user.

The identification information may be a different value for the first user when the subsequent PPDU does not carry the retransmitted data.

For multiple users, such as a second user and a third user, a different value of identification information may be assigned to each user. For example, the value of the identification information assigned to the second user may be different from the value of the identification information assigned to the third user.

For a plurality of users such as the fourth user and the fifth user, each user may be assigned the same identification information. For example, the value of the identification information assigned to the fourth user may be the same as the value of the identification information assigned to the fifth user. In this case, the identification information may be considered independently for each user such that the STA-ID and the identification information are jointly encoded to show whether it is information of retransmission.

In the case where the MRQ Sequence Identifier (MSI) is carried in a Link Adaptation (LA) control subfield in the MAC layer, the identification information in the PHY or MAC may carry the same value of the MSI field. The recommended MCS in the LA control field may be utilized to decide on the retransmitted information.

In some embodiments, the length of all HARQ units in the PPDU is the same during the HARQ process. In some embodiments, the length of all HARQ units in the data unit PPDU1 or PPDU3 is the same. In some embodiments, the length of the HARQ unit in data unit PPDU3 is the same as the length of the HARQ unit in data unit PPDU 1.

In some embodiments, the lengths of the HARQ units of different PPDUs may be different during the HARQ process. In some embodiments, the length of the HARQ unit in data unit PPDU1 may be allowed to be different from the length of another HARQ unit in data unit PPDU 1. In some embodiments, the length of the HARQ unit in data unit PPDU3 may be allowed to be different from the length of another HARQ unit in data unit PPDU 3. In some embodiments, the length of one or more HARQ units in data unit PPDU3 may be allowed to be different from the length of one or more HARQ units in data unit PPDU 1.

At S150, the electronic device 400 may combine the retransmitted HARQ unit with the previously stored HARQ unit.

Hereinafter, HARQ related information will be described.

In some embodiments, the HARQ related information may be carried in the PHY of the data unit PPDU 3. For example, the HARQ related information may be carried in a preamble of the data unit PPDU 3. In some embodiments, the preamble may include a SIG field dedicated to the HARQ process, and the SIG field may be included in a PPDU of the retransmitted HARQ unit. It may carry the same MSI information (e.g., any identification information) as compared to the initial transmission, where the location carrying the MSI information may be different. In some embodiments, data units PPDU1 and PPDU3 may carry the same MSI information, but the location of the MSI information in carrying data unit PPDU1 may be different from the location of the MSI information in carrying data unit PPDU 3. For example, the MSI information in the data unit PPDU1 may be carried on the MAC header, but the MSI information in the data unit PPDU3 may be carried in the SIG field of the PHY preamble of the data unit PPDU 3.

In some embodiments, the HARQ related information carried in the data unit PPDU3 may be the same as the HARQ related information carried in the data unit PPDU 2. In some embodiments, the HARQ related information carried in data unit PPDU3 may be part or a subset of the HARQ related information carried in data unit PPDU 2.

In some embodiments, HARQ related information may be carried in the MAC frame of PPDU2 and all or part of the HARQ related information carried in data unit PPDU2 may be carried in the PHY preamble of PPDU3, as the MAC can have more space. Then, when the HARQ unit is retransmitted first at the electronic device 400, the electronic device 300 may be allowed to select which HARQ unit should be carried and processed. The HARQ related information in the data unit PPDU3 may be a subset of the HARQ related information in the data unit PPDU 2. For example, in response to data unit PPDU2, the first N HARQ units (e.g., CW or MPDU) may be retransmitted with HARQ related information in the SIG field in the PHY preamble of data unit PPDU 3.

In some embodiments, the HARQ related information may be carried in the PHY preamble of the data unit PPDU2, and all or part of the HARQ related information in the data unit PPDU2 may be carried in the PHY preamble of the data unit PPDU 3. In order to carry a sufficient amount of HARQ related information, the WLAN system may support a PPDU type without a data field, wherein the HARQ related information is carried in the SIG field instead of in the MAC frame of the data unit PPDU 3. Then, when the HARQ unit is retransmitted first at the electronic device 400, the electronic device 300 may be allowed to select which HARQ unit should be carried and processed. The HARQ related information in the data unit PPDU3 may be a subset of the HARQ related information in the data unit PPDU 2. For example, in response to data unit PPDU2, the first N HARQ units (e.g., CW or MPDU) may be retransmitted with HARQ related information in the SIG field in the PHY preamble of data unit PPDU 3. Alternatively, the HARQ-related information may indicate that all requested HARQ units are retransmitted. In this case, the electronic device 300 may transmit the data unit PPDU4 including the retransmitted HARQ unit after transmitting the data unit PPDU3, and the electronic device 400 may decode the retransmitted HARQ unit using the parameters in the SIG field of the data unit PPDU4. In some embodiments, the parameters in the SIG field of the data unit PPDU4 may be equal to or different from the parameters in the SIG field of the data unit PPDU 2. In some embodiments, the data unit PPDU4 may be received by SIFS after the data unit PPDU 3.

In some embodiments, the HARQ related information may be carried in the PHY preamble of the data unit PPDU2, and all or part of the HARQ related information in the data unit PPDU2 may be carried in the PHY preamble of the data unit PPDU 3. In order to carry a sufficient amount of HARQ related information, the WLAN system may support a PPDU format having a specific type of SIG field, wherein the HARQ related information is carried in a MAC frame of this type of SIG field instead of the data unit PPDU3, and the type of SIG field does not include parameters to be used for decoding a data field including a retransmission HARQ unit. In some embodiments, the type or format of the SIG field may be different from the type or format of the L-SIG field, different from the type or format of the U-SIG field, and different from the type or format of the EHT-SIG field. Then, when carrying retransmission data in PPDU3, the electronic device 300 may be allowed to select which HARQ unit should be carried and processed. The HARQ related information in the data unit PPDU3 may be a subset of the HARQ related information in the data unit PPDU 2. For example, in response to data unit PPDU2, the first N HARQ units (e.g., CW or MPDU) may be retransmitted with HARQ related information in the SIG field in the PHY preamble of data unit PPDU 3. Alternatively, the HARQ-related information may indicate that all requested HARQ units are retransmitted. In this case, since this type of SIG field includes HARQ-related information that is not used to correctly decode parameters of a data field of a HARQ unit including retransmission, the electronic device 400 may assume that parameters used to decode the data field of the data unit PPDU3 are the same as parameters in the SIG field of the data unit PPDU1, and decode the data field of the data unit PPDU3 using the parameters in the SIG field of the data unit PPDU 1.

In some embodiments, the HARQ related information may be carried in the PHY preamble of the data unit PPDU2, and all or part of the HARQ related information in the data unit PPDU2 may be carried in the PHY preamble of the data unit PPDU 3. In order to carry a sufficient amount of HARQ related information, the WLAN system may support a specific type of PPDU format having a SIG type, wherein the HARQ related information is carried in a SIG field of this type instead of the MAC frame of the data unit PPDU3, and the type of the SIG field includes parameters to be used for decoding a data field including a retransmission HARQ unit. Then, when carrying the retransmitted data in the data unit PPDU3, the electronic device 300 may be allowed to select which HARQ related information should be carried and processed. The HARQ related information in the data unit PPDU3 may be a subset of the HARQ related information in the data unit PPDU 2. For example, in response to data unit PPDU2, the first N HARQ units (e.g., CW or MPDU) may be retransmitted with HARQ related information in the SIG field in the PHY preamble of data unit PPDU 3. Alternatively, the HARQ-related information may indicate that all requested HARQ units are retransmitted. In this case, since this type of SIG field includes HARQ-related information and parameters to be used for decoding the data field, the electronic device 400 may decode the data field of the data unit PPDU3 using the parameters in the type of SIG field of the data unit PPDU 3. The control information may contain information of public or user specific use.

In some embodiments, the data unit PPDU3 in the HARQ process may contain an identification information field as identification information to indicate whether the data unit PPDU3 contains a HARQ unit for the first user retransmission. Since the unsuccessfully decoded HARQ unit may not be immediately retransmitted or information other than the unsuccessfully decoded HARQ unit may be initially urgently transmitted to the first user, the next PPDU immediately following the previous PPDU addressed to the first user may not necessarily contain the retransmitted HARQ unit even though the electronic device 300 receives the HARQ-related information as HARQ feedback information from the electronic device 400.

In some embodiments, the HARQ-related information may indicate one codeword or two codewords, wherein the number of HARQ units that may be indicated by the HARQ-related information is greater than the number of codewords NCW. In some embodiments, a 4-bit bitmap or a field representing a state representing 16 states in a lookup table may be used as HARQ related information as shown in tables 7 and 8 below. For example, when the number of CW is insufficient to use the entire bitmap or the entire state, 1 may indicate that the corresponding HARQ unit composed of M codewords includes an error or retransmission of the corresponding HARQ unit according to whether the corresponding HARQ unit is included during the HARQ process.

TABLE 7

In table 7, all 1's in the bitmap may indicate that the entire information should be retransmitted.

TABLE 8

Status of	Description of the invention
		0	Not including errors
1	The first HARQ unit includes an error. The CW associated with the first HARQ unit should be retransmitted.
		…
15	All codewords are retransmitted.

In some embodiments, the HARQ-related information may include a case where at least one HARQ unit includes an error, such that the corresponding indication should be retained in bitmap format or in a lookup table format (e.g., 0 in a 4-bit lookup table format, when all information is correctly detected or decoded).

In some embodiments, any HARQ related information as described above in the PHY preamble may be carried in one of the SIG fields, where the HARQ related information is from a PPDU carrying HARQ feedback information. For example, as shown in fig. 22, HARQ related information carried in the MAC portion of the data unit PPDU2 may be copied or recalculated (or mapped) to fit the preamble portion of the data unit PPDU 3. The HARQ related information in the preamble may help the PHY entity itself to operate the HARQ process when receiving the data unit PPDU 3.

In some embodiments, some of the SIG fields may be reinterpretated assuming that some of the SIG fields are not updated during the retransmission.

In some embodiments, the reservation information (such as valid or disregarded) in the SIG field may be used for HARQ purposes. For example, reserved bits of the SIG field may be used as HARQ related information.

To ensure space in the SIG field, the WLAN system may support a PPDU type without a data field, where HARQ-related information is carried in the SIG field instead of the MAC frame. There is a control signal indicating this type of PPDU. This type of PPDU may be used as in one of the sequences shown in fig. 22 and 28, for example. The SIG field may provide up to a number of bits of 26 SIG OFDM symbols when the SIG field is modulated using BPSK and a 1/2 coding rate. For example, when 32 SIG OFDM symbols are supported, then 104 bytes may be carried in the SIG field. The SIG field may provide up to 52 x bits of the number of SIG OFDM symbols when the SIG field is modulated using QPSK and a 1/2 coding rate. For example, when 32 SIG OFDM symbols are supported, then 208 bytes may be carried in the SIG field. The SIG field may provide a number of bits up to 104 x SIG OFDM symbols when modulating the SIG field using 16-QAM and a 1/2 coding rate. For example, when 32 SIG OFDM symbols are supported, 416 bytes may be carried in the SIG field.

Assuming that the length of the SIG field may be longer, the CRC field and the tail field may be located periodically.

The PPDU may carry first information for implicitly or explicitly indicating whether the PPDU contains at least one retransmitted HARQ unit. The first information may be user-specific in that at least one initial HARQ unit and at least one retransmitted HARQ unit may be jointly transmitted in one PPDU allocated to a plurality of users.

In some embodiments, the first information may be a STA-ID. When the electronic device 400 requests retransmission, a subsequent PPDU with the same STA-ID implicitly means that the PPDU includes at least one retransmitted HARQ unit. However, this may lead to delay problems when the electronic device 300 has urgent new information to send.

In some embodiments, to allow the same STA to transmit new information when the HARQ process is not complete, a first field may be used to indicate whether it is retransmitted information. Although the transmitted information is stored for a specific STA at the receiver side, when a PPDU having the same STA-ID is received, the receiver needs to check the first field to see whether the transmitted information should be combined into the stored information. If it indicates new initial information to be transmitted, the electronic device 400 may process it separately from the stored information. For example, a reserved subfield (e.g., B15) in a user field in an EHT-SIG field for non-MU-MIMO allocation may be used as the first field.

In some embodiments, the first information may be MSI. When the receiver first obtains a PPDU with a first MSI value, the electronic device 400 may treat it as an initial transmission for a particular STA-ID. Once the electronic device 400 obtains the first value of MSI for a particular STA-ID, this PPDU may mean that it includes a HARQ unit for retransmissions of the particular STA-ID. Once the receiver first obtains the second MSI value for a particular STA-ID, the STA needs to start a new HARQ process of the second MSI in parallel for the particular STA-ID, whether or not the electronic device 400 stores HARQ elements associated with the first MSI value.

Hereinafter, an initial HARQ unit and a retransmitted HARQ unit in a HARQ process according to various embodiments will be described with reference to fig. 23 to 26.

Fig. 23 shows an initial HARQ unit and a retransmitted HARQ unit in an HARQ process according to an embodiment.

As described above, when an MPDU is used as a HARQ unit, the PHY entity responsible for HARQ operation is unaware of the MPDU. The simplest solution is to send the entire packet regardless of which MPDU(s) cannot be decoded.

Referring to fig. 23, only the data unit MPDU2 cannot be decoded, but all MPDUs in the previous PPDU are retransmitted. However, this scheme may be inefficient in the presence of burst errors, where the errors occur in a narrow portion of the data information.

Fig. 24 shows an initial HARQ unit and a retransmitted HARQ unit in a HARQ process according to another embodiment.

As described above, the codeword may be used as a HARQ unit. Since the codeword is a processing unit in the PHY layer, the electronic device 400 at the PHY needs to know whether an erroneous codeword was transmitted and which erroneous codeword was retransmitted. Based on this information, the electronic device 400 may combine the retransmitted CW to the stored CW.

Referring to fig. 24, the electronic device 400 may request the electronic device 300 to retransmit codewords CW2 through CW4 that have not been decoded. After electronic device 400 receives the retransmitted codewords CW2 through CW4, electronic device 400 may combine the retransmitted codewords CW2 through CW4 with the previous codewords CW2 through CW4 to forward the decoded bit stream to the MAC entity. The MAC entity may terminate the HARQ process if there is no error in the decoded bit stream.

Fig. 25 shows an initial HARQ unit and a retransmitted HARQ unit in a HARQ process according to another embodiment.

Referring to fig. 25, LDPC codewords 1,2, … N as HARQ units are transmitted, and each codeword includes information bits 1,2, … N and LDPC parity bits 1,2, … N. After electronic device 400 fails to decode codewords 2 and 3, electronic device 400 may transmit HARQ feedback information indicating that codewords 2 and 3 fail to decode. The electronic device 300 may retransmit parity bit 2 of codeword 2 without information bit 2 of codeword 2 and retransmit parity bit 3 of codeword 3 without information bit 3 of codeword 3, assuming that the information bits used to generate the parity bits to be retransmitted are the same as the information bits used to generate the initially transmitted parity bits.

Fig. 26 shows an initial HARQ unit and a retransmitted HARQ unit in a HARQ process according to another embodiment.

Referring to fig. 25, LDPC codewords 1,2, … N as HARQ units are transmitted, and each codeword includes information bits 1,2, … N and LDPC parity bits 1,2, … N. After electronic device 400 fails to decode codewords 2 and 3, electronic device 400 may transmit HARQ feedback information indicating that codewords 2 and 3 fail to decode. For example, when electronic device 300 applies a different puncturing pattern (e.g., a different code rate) that includes bits not included in the initially transmitted codeword, electronic device 300 may retransmit parity bit 2 'of codeword 2 without retransmitting information bit 2 of codeword 2 and parity bit 3' of codeword 3 without retransmitting information bit 3 of codeword 3.

In some embodiments, the length of the HARQ units may be different between transmission and retransmission, as HARQ units that remain the same size may result in more padding during retransmission. On the receiver side, its corresponding information has been stored and used when combined with the retransmitted information.

In some embodiments, padding may be appended to the retransmitted parity bits to fill the HARQ unit when the length of the HARQ unit is sufficiently large compared to the size of the retransmitted information. For example, when the length of the HARQ unit is greater than the size of the retransmitted information, the HARQ unit may include the parity bits and the padding bits of the retransmission.

In some embodiments, when the length of the HARQ unit is sufficiently large compared to the size of the retransmitted information, the retransmitted parity bits may be repeated in the HARQ unit, and then padding may be appended to the retransmitted parity bits in the HARQ unit. For example, when the length of the HARQ unit is greater than the size of the retransmitted information, the HARQ unit may include a plurality of repetitions of the retransmitted parity bits and padding bits.

Fig. 27 shows a HARQ unit in a HARQ process according to an embodiment.

As shown in fig. 27, a codeword set may be used as the HARQ unit. In some embodiments, the same number of codewords may be included in all codeword sets. In some embodiments, all sets except the last set of codewords may include the same number of codewords, and the number of codewords in the last set is equal to or less than the number of codewords included in all sets except the last set.

In some embodiments, the preamble portion of the PPDU in the HARQ process may contain HARQ related information indicating which HARQ unit(s) contain errors. For example, there is an NCW calculated in the PHY layer. If the PHY layer recognizes an error in the codeword, HARQ-related information may be transmitted to the MAC layer using one of the RXVECTOR parameters when processing the received PPDU.

The HARQ-related information may be indicated using a bitmap including a plurality of bits. Each of the plurality of bits may be associated with a respective HARQ unit of the plurality of HARQ units and indicate whether the associated HARQ unit is being retransmitted. If the HARQ related information is indicated by a 6-bit bitmap and the value of the 6-bit bitmap is 110000, it may mean that the first two HARQ units of the six HARQ units contain errors. If the station receives HARQ related information indicated by the bitmap, the station may retransmit one or more of the codewords respectively indicated by bits in the bitmap.

The HARQ related information may be indicated with a field set of states equal to the plurality of states in the lookup table. If the look-up table indicates HARQ related information, all potential error combinations may be listed. For example, if the value of the lookup table is 111111, it may mean that all HARQ units contain errors or that all HARQ units should be retransmitted. If the station receives HARQ related information indicated by the lookup table, the station may retransmit one or more codewords indicated by the value of the lookup table.

HARQ related information may be carried in the MAC layer. Each state of the CW (or each state of the HARQ unit) may be transmitted through PPDU2 in fig. 22.

A portion of the compressed information or HARQ related information may be retransmitted in a PHY preamble (e.g., PPDU3 shown in fig. 22) in a subsequent PPDU.

In some embodiments, when the electronic device 400 receives a retransmitted HARQ unit, the electronic device 400 may check the HARQ related information to know which HARQ units are retransmitted. In some embodiments, the electronic device 300 may not immediately retransmit the HARQ unit requested by the electronic device 400, depending on the priority of the transmitter. For example, when the electronic device 400 transmits HARQ feedback information to the electronic device 300 to request the electronic device 300 to retransmit the first two HARQ units having a bitmap of 110000, the electronic device 300 may transmit a PPDU including only the first HARQ unit having HARQ related information indicated by the bitmap of 100000 and then may transmit a subsequent PPDU including the second HARQ unit having HARQ related information indicated by the bitmap of 010000.

Fig. 28 shows a HARQ process according to an embodiment.

Referring to fig. 28, at S210, the electronic device 300 may transmit a data unit PPDU11 including a plurality of HARQ units.

At S220, the electronic device 400 may not be able to decode at least one HARQ unit of the plurality of HARQ units in the data unit PPDU11. For example, the electronic device 400 may not be able to decode HARQ units 2 to 5.

At S230, the electronic device 400 may transmit a data unit PPDU12 including HARQ feedback information to request the electronic device 300 to retransmit one or more HARQ units that have not been decoded. For example, the HARQ feedback information may request the electronic device 300 to retransmit the HARQ units 2 to 5.

At S240, the electronic device 300 may transmit a data unit PPDU13 including a plurality of HARQ units. In some cases, the electronic device 300 may not be allowed to retransmit HARQ units that the electronic device 400 did not request the electronic device 300 to retransmit. For example, the data unit PPDU13 may include HARQ unit 1, which the electronic device 400 does not request retransmission by the electronic device 300, and non-allowed HARQ unit 5, which the electronic device 400 requests retransmission by the electronic device 300.

At S250, the electronic device 400 may determine whether a plurality of HARQ units in the data unit PPDU13 include HARQ units that the electronic device 400 does not request retransmission of the electronic device 300, and may ignore all HARQ units in the data unit PPDU13 or all retransmitted HARQ units when it is determined that the plurality of HARQ units in the data unit PPDU13 include unsolicited HARQ. For example, since the data unit PPDU13 includes HARQ unit 1 that the electronic device 400 does not request the electronic device 300, the electronic device 400 may ignore all retransmitted HARQ units in the data unit PPDU 13.

At 260, the electronic device 400 may transmit a data unit PPDU 14 including HARQ feedback information to request the electronic device 300 to retransmit one or more HARQ units that the electronic device 400 ignores or does not receive again. For example, since the receiver 200 ignores the retransmitted HARQ unit 5 and does not receive the HARQ units 2 to 4, the HARQ feedback information may request the electronic device 300 to retransmit the HARQ units 2 to 5 again.

Any of the above embodiments may be combined to support HARQ processes or LA processes or both.

To illustrate the interchangeability of hardware and software, various illustrative blocks, modules, components, methods, operations, instructions, and algorithms have been described generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Those skilled in the art can implement the described functionality in varying ways for each particular application.

References to elements in the singular are not intended to mean one and only one, but rather one or more, unless specifically stated. For example, "a" module may refer to one or more modules. Elements beginning with "a", "an", "the" or "the" do not preclude the presence of additional identical elements, without further constraint.

Headings and subheadings, if any, are used for convenience only and do not limit the subject technology. The word "exemplary" is used to mean serving as an example or illustration. To the extent that the terms "including", "having", etc. are used, such terms are intended to be inclusive in a manner similar to the term "comprising" as "comprising" is interpreted when employed as a transitional word in a claim. Relational terms such as first and second, and the like may be used to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.

Phrases such as one aspect, this aspect, another aspect, some aspects, one or more aspects, implementations, the implementation, another implementation, some implementations, one or more implementations, an example, this example, another example, some examples, one or more examples, a configuration, the configuration, another configuration, some configurations, one or more configurations, subject technology, disclosure, the present disclosure, other variations thereof, and the like are for convenience and do not imply that disclosure relating to such phrases is necessary for the subject technology or that such disclosure applies to all configurations of the subject technology. The disclosure relating to such one or more phrases may apply to all configurations or one or more configurations. The disclosure relating to such phrases may provide one or more examples. A phrase such as one or more aspects may refer to one or more aspects and vice versa, and the same applies similarly to other preceding phrases.

The phrase "at least one" preceding a series of items (where the term "and" or "is used to isolate any item) modifies the entire list rather than each member of the list. The phrase "at least one" does not require the selection of at least one item; rather, the phrase allows for the inclusion of at least one of any one item and/or the meaning of at least one of any combination of items and/or at least one of each item. For example, each of the phrases "at least one of A, B and C" or "at least one of A, B or C" refers to a alone, B alone, or C alone; A. any combination of B and C; and/or at least one of each of A, B and C.

It is to be understood that the specific order or hierarchy of steps, operations, or processes disclosed is an illustration of exemplary approaches. Unless explicitly stated otherwise, it is to be understood that the particular order or hierarchy of steps, operations or processes may be performed in a different order. Some steps, operations, or processes may be performed concurrently or as part of one or more other steps, operations, or processes. The accompanying method claims present elements of the various steps, operations, or processes in a sample order, if any, and are not meant to be limited to the specific order or hierarchy presented. These may be performed serially, linearly, in parallel or in a different order. It should be understood that the described instructions, operations, and systems may generally be integrated together in a single software/hardware product or packaged into multiple software/hardware products.

The present disclosure is provided to enable any person skilled in the art to practice the various aspects described herein. In some instances, well-known structures and components are shown in block diagram form in order to avoid obscuring the concepts of the subject technology. The present disclosure provides various examples of the subject technology, and the subject technology is not limited to these examples. Various modifications to these aspects will be readily apparent to those skilled in the art, and the principles described herein may be applied to other aspects.

All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Furthermore, no disclosure herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35u.s.c. ≡112, unless the element is explicitly recited using phrase means for method claims or, in the case of method claims, the element is recited using phrase steps for method claims.

The title, background, brief description, abstract and drawings of the drawings are hereby incorporated into the present disclosure, and are provided as illustrative examples of the present disclosure and not as limiting descriptions. It is submitted with the understanding that they will not be used to limit the scope or meaning of the claims. In addition, in the detailed description, it can be seen that the description provides illustrative examples, and that various features are grouped together in various embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed subject matter requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed configuration or operation. The following claims are hereby incorporated into the detailed description, with each claim standing on its own as a separately claimed subject matter.

The claims are not intended to be limited to the aspects described herein but are to be accorded the full scope consistent with the language claims and encompassing all legal equivalents. However, none of the claims is intended to cover a subject matter that does not meet the requirements of the applicable patent statutes, nor should it be interpreted in this manner.

Claims (20)

1. An electronic device for facilitating wireless communication, the device comprising:

one or more memories; and

one or more processors coupled to the one or more memories, the one or more processors configured to cause:

receiving a first data unit, wherein the first data unit comprises a first Short Training Field (STF), a first Long Training Field (LTF), a signal field, a second STF, a second LTF and a data field comprising a first hybrid automatic repeat request (HARQ) unit;

transmitting a second data unit including first HARQ related information indicating that the first HARQ unit cannot be decoded;

receiving a third data unit including a preamble, wherein the preamble includes a first STF, a first LTF, a signal field, a second STF, and a second LTF, and the third data unit includes second HARQ-related information indicating whether the third data unit includes retransmitted data;

obtaining a second HARQ unit based on determining that the second HARQ related information indicates that the third data unit includes retransmitted data; and

and decoding the second HARQ unit by using the first HARQ unit.

2. The electronic device of claim 1, wherein the second HARQ related information is included in a signal field of a preamble of the third data unit.

3. The electronic device of claim 2, wherein the signal field comprises a user field comprising a first subfield indicating a site identifier and a second subfield indicating that the third data unit comprises retransmitted data.

4. The electronic device of claim 1, wherein:

the first data unit includes a MAC header having a link adaptation control subfield including a first MCS modulation and coding scheme request MRQ subfield and a first MRQ sequence identifier MSI subfield,

the third data unit includes a MAC header having a link adaptation control subfield including a second MRQ subfield and a second MSI subfield,

the second MSI subfield being set equal to the MSI value indicated by the first MSI subfield indicates that the third data unit comprises retransmitted data, and

the second MSI subfield set to be different from the MSI value indicated by the first MSI subfield indicates that a third data unit does not include retransmitted data.

5. The electronic device of claim 1, wherein the second HARQ-related information is indicated by a bitmap comprising a plurality of bits, each of the plurality of bits associated with a respective one of the HARQ units in the first data unit.

6. The electronic device of claim 1, wherein the second HARQ-related information is indicated by a field set equal to one of a plurality of states in a lookup table representing a respective one of the error combinations of HARQ units in the first data unit.

7. The electronic device of claim 1, wherein a scrambler seed for the second HARQ unit is the same as a scrambler seed for the first HARQ unit.

8. The electronic device of claim 1, wherein obtaining the second HARQ unit comprises:

receiving a fourth data unit following the third data unit, the fourth data unit comprising a first short training field, STF, a first long training field, LTF, a signal field, a second STF, and a second LTF, and a data field; and

and obtaining the second HARQ unit from the data field of the fourth data unit according to the parameters in the signal field in the fourth data unit.

9. The electronic device of claim 1, wherein the signal field of the third data unit does not include parameters for obtaining the second HARQ unit, and the second HARQ unit is obtained from one or more parameters in the signal field in the first data unit.

10. The electronic device of claim 1, wherein the first HARQ unit is a low density parity check, LDPC, codeword comprising information bits and parity bits.

11. The electronic device of claim 10, wherein the second HARQ unit is a low density parity check, LDPC, codeword comprising information bits and parity bits.

12. The electronic device of claim 10, wherein the second HARQ unit is a low density parity check, LDPC, codeword comprising parity bits and no information bits.

13. The electronic device of claim 1, wherein the first HARQ unit is a set of low density parity check, LDPC, codewords.

14. The electronic device of claim 1, wherein the first HARQ unit is an MPDU.

15. The electronic device of claim 1, wherein the one or more processors are configured to further cause:

Discarding the first HARQ unit if the third data unit comprises a HARQ unit not indicated by the first HARQ related information.

16. An electronic device for facilitating wireless communication, the device comprising:

one or more memories; and

one or more processors coupled to the one or more memories, the one or more processors configured to cause:

transmitting a first data unit comprising a first short training field STF, a first long training field LTF, a signal field, a second STF, a second LTF, and a data field comprising a first hybrid automatic repeat request HARQ unit;

receiving a second data unit comprising first HARQ related information indicating that the first HARQ unit failed to be decoded; and

a third data unit including a preamble is transmitted, wherein the preamble includes a first STF, a first LTF, a signal field, a second STF, and a second LTF, and the third data unit includes second HARQ-related information indicating whether the third data unit includes retransmitted data.

17. The electronic device of claim 16, wherein the second HARQ related information is included in a signal field of a preamble of the third data unit.

18. The electronic device of claim 17, wherein the signal field comprises a user field comprising a first subfield indicating a site identifier and a second subfield indicating that the third data unit comprises retransmitted data.

19. The electronic device of claim 16, wherein:

the first data unit includes a MAC header having a link adaptation control subfield including a first MCS modulation and coding scheme request MRQ subfield and a first MRQ sequence identifier MSI subfield,

the third data unit includes a MAC header having a link adaptation control subfield including a second MRQ subfield and a second MSI subfield,

the second MSI subfield being set equal to the MSI value indicated by the first MSI subfield indicates that the third data unit comprises retransmitted data, and

the second MSI subfield set to be different from the MSI value indicated by the first MSI subfield indicates that a third data unit does not include retransmitted data.

20. A method performed by an electronic device, comprising:

receiving a first data unit, wherein the first data unit comprises a first Short Training Field (STF), a first Long Training Field (LTF), a signal field, a second STF, a second LTF and a data field comprising a first hybrid automatic repeat request (HARQ) unit;

Transmitting a second data unit including first HARQ related information indicating that the first HARQ unit cannot be decoded;

receiving a third data unit including a preamble, wherein the preamble includes a first STF, a first LTF, a signal field, a second STF, and a second LTF, and the third data unit includes second HARQ-related information indicating whether the third data unit includes retransmitted data;

obtaining a second HARQ unit based on determining that the second HARQ related information indicates that the third data unit includes retransmitted data; and

and decoding the second HARQ unit by using the first HARQ unit.