Abstract: This disclosure provides systems, methods and apparatus, including computer programs encoded on computer storage media, for encoding data for wireless transmissions. In one aspect, a wireless device may encode a number (M) of systematic bits for transmission to a receiving device. The systematic bits may be encoded using a low-density parity-check (LDPC) code to produce an LDPC codeword. The LDPC codeword may include a number (N) of codeword bits, including the M systematic bits and one or more parity bits. The wireless device may further puncture a number (K) of the codeword bits to produce a punctured codeword having a code rate M/(N?K)>5/6. The wireless device may transmit the N?K remaining codeword bits, over a wireless channel, to a receiving device.

Abstract: This disclosure provides methods, devices and systems for encoding data for wireless communication to achieve probabilistic amplitude shaping. In some implementations, a transmitting device may achieve a fixed information block length (N), at least in part, by iteratively encoding the information bits until the number of amplitude-shaped bits combined with the number of unshaped bits is greater than or equal to a maximum payload length. For example, the maximum payload length may be equal to N. If the resulting number of amplitude-shaped bits plus the number of unshaped bits is less than N, the transmitting device may add one or more padding bits to the information block to achieve the fixed information block length.

Abstract: This disclosure provides systems, methods and apparatuses for data retransmissions in a wireless network. In some implementations, a wireless communication device may transmit a first data unit to a receiving device, may receive a first hybrid automatic repeat request (HARQ) feedback frame indicating that a portion of the first data unit was not successfully decoded by the receiving device, may retransmit the indicated portion of the first data unit to the receiving device in response to the first HARQ feedback frame, and may transmit a second data unit, different than the first data unit, to the receiving device concurrently with the retransmission of the indicated portion of the first data unit.

Abstract: This disclosure provides methods, devices and systems for encoding data in wireless communications. Some implementations more specifically relate to performing a first encoding operation on data bits of a code block to shape the amplitudes of the resultant symbols such that the amplitudes have a non-uniform distribution. In some aspects, the probabilities associated with the respective amplitudes generally increase with decreasing amplitude. For example, the non-uniform distribution of the amplitudes of the symbols may be approximately Gaussian. In some aspects, the first encoding operation is or includes a prefix encoding operation having an effective coding rate greater than 0.94 but less than 1. The first encoding operation is followed by a second encoding operation that also adds redundancy but does not alter the data bits themselves. In some aspects, the second encoding operation is or includes a low-density parity-check (LDPC) encoding operation associated with a coding rate greater than 5/6.

Abstract: This disclosure provides systems, methods and apparatus, including computer programs encoded on computer storage media, for low density parity check (LDPC)-based incremental redundancy (IR) hybrid automatic repeat request (HARQ) transmission processing. In one aspect, an apparatus for wireless communications is configured to generate a first packet using a LDPC encoding process. The apparatus is further configured to generate coded bits using a second LDPC encoding process if the first packet is not successfully decoded by a wireless device, generate a second packet including at least some of the coded bits generated using the second LDPC encoding process, and output the second packet for transmission.

Abstract: This disclosure provides methods, devices and systems for encoding data for wireless communication to achieve probabilistic amplitude shaping. In some implementations, a transmitting device may achieve a fixed information block length (N), at least in part, by iteratively encoding the information bits until the number of amplitude-shaped bits combined with the number of unshaped bits is greater than or equal to a maximum payload length. For example, the maximum payload length may be equal to N. If the resulting number of amplitude-shaped bits plus the number of unshaped bits is less than N, the transmitting device may add one or more padding bits to the information block to achieve the fixed information block length.

Abstract: This disclosure provides methods, devices and systems for encoding data in wireless communications. Some implementations more specifically relate to performing a first encoding operation on data bits of a code block to shape the amplitudes of the resultant symbols such that the amplitudes have a non-uniform distribution. In some aspects, the probabilities associated with the respective amplitudes generally increase with decreasing amplitude. For example, the non-uniform distribution of the amplitudes of the symbols may be approximately Gaussian. In some aspects, the first encoding operation is or includes a prefix encoding operation having an effective coding rate greater than 0.94 but less than 1. The first encoding operation is followed by a second encoding operation that also adds redundancy but does not alter the data bits themselves. In some aspects, the second encoding operation is or includes a low-density parity-check (LDPC) encoding operation associated with a coding rate greater than 5/6.

Abstract: This disclosure provides systems, methods and apparatus, including computer programs encoded on computer storage media, for encoding data for wireless transmissions. In one aspect, a wireless device may encode a number (M) of systematic bits for transmission to a receiving device. The systematic bits may be encoded using a low-density parity-check (LDPC) code to produce an LDPC codeword. The LDPC codeword may include a number (N) of codeword bits, including the M systematic bits and one or more parity bits. The wireless device may further puncture a number (K) of the codeword bits to produce a punctured codeword having a code rate M/(N?K)>5/6. The wireless device may transmit the N?K remaining codeword bits, over a wireless channel, to a receiving device.

Abstract: This disclosure provides systems, methods, and apparatus, including computer programs encoded on computer-readable media, for a link adaptation protocol in a wireless local area network (WLAN). In one aspect, the link adaptation protocol may be used to select a transmission rate option (such as a modulation and coding scheme (MCS)) for communications from a first WLAN device to a second WLAN device based on wireless channel conditions. This disclosure includes several example message sequences for the link adaptation protocol which can accommodate a variety of uplink or downlink data transmission designs, including single user (SU) and multi-user (MU) transmissions. The example message sequences may be used with orthogonal frequency division multiple access (OFDMA), multiple-input-multiple-output (MIMO), and beamformed transmissions.

Abstract: This disclosure provides systems, methods, and apparatus for link adaptation in a wireless local area network (WLAN). A link adaptation test packet from a first WLAN device to a second WLAN device may be formatted as a multiple-input-multiple-output (MIMO) transmission and may include one or more test portions for link quality estimation of the MIMO transmission. A link quality estimation portion of the test packet may permit measurement of link quality for various spatial streams of the MIMO transmission. The link adaptation test packet may enable a fast rate adaptation of a communication link based on the impact of interference to the various spatial streams. The second WLAN device may provide feedback information regarding the one or more test portions. The feedback information may be used to determine a transmission rate for a subsequent transmission from the first WLAN device to the second WLAN device based on wireless channel conditions.

Abstract: This disclosure provides systems, methods, and apparatus, including computer programs encoded on computer-readable media, for link adaptation in a wireless local area network (WLAN). A link adaptation test packet from a first WLAN device to a second WLAN may include a plurality of link adaptation test portions that are generated using a corresponding plurality of transmission rate options. For example, the plurality of link adaptation test portions may be modulated using different modulation and coding scheme (MCS) options. Thus, a single test packet may be used to evaluate different transmission rate options. The second WLAN device may provide feedback information regarding the link adaptation test portions. The feedback information may be used to determine a transmission rate for a subsequent transmission from the first WLAN device to the second WLAN device based on wireless channel conditions.

Abstract: This disclosure provides methods, devices and systems for amplitude shaping encoding, and specifically, for indicating boundaries in bitstreams encoded using amplitude shaping encoding. In some aspects, a transmitting device may insert, into an bitstream to indicate a boundary, a sequence of amplitude bits not associated with any patterns of bit values in a lookup table used for the encoding. In some other aspects, a transmitting device may monitor a length of the amplitude bits in a bitstream during the encoding and stop the encoding on information bits at an end of a current data unit responsive to the length reaching a threshold. In some other aspects, a transmitting device may monitor the length of the information bits and, for each data unit, determine whether a boundary is or would be reached.

Abstract: This disclosure provides methods, devices and systems for link adaptation in wireless communications. Some implementations more specifically relate to transmitter-based modulation and coding scheme (MCS) selection. A transmitting device transmits a test packet, over a wireless channel, to a receiving device. The receiving device generates one or more signal-to-interference-plus-noise ratio (SINR) estimates for the wireless channel based on the received sounding packet. In some aspects, each SINR estimate may be associated with a particular modulation order. In some other aspects, each SINR estimate may be generated based on a transmitter configuration or a receiver type to be used for subsequent communications between the transmitting device and the receiving device. The receiving device transmits feedback, including the SINR estimates, to the transmitting device.

Abstract: This disclosure provides systems, methods, and apparatus, including computer programs encoded on computer-readable media, for implementing a hybrid automatic repeat request (HARQ) protocol in a wireless local area network (WLAN). A station (STA) may send a HARQ transmission to another STA. The HARQ protocol may support the use of different types of feedback from the receiving STA to control the HARQ retransmission process. This disclosure provides example message formats to support HARQ transmission and HARQ feedback in a WLAN.

Abstract: This disclosure provides methods, devices and systems for encoding data for wireless communication to achieve a desired amplitude distribution. Some implementations more specifically relate to performing an encoding operation to shape the amplitudes of the resultant symbols such that the amplitudes have a non-uniform distribution. In some implementations of the non-uniform distribution, the probabilities associated with the respective amplitudes generally increase with decreasing amplitude. Some implementations enable the tracking of MPDU boundaries to facilitate successful decoding by a receiving device. Additionally or alternatively, some implementations enable the determination of a packet length after performing the amplitude shaping, which enables a transmitting device to determine the number of padding bits to add to the payload and to signal the packet length to a receiving device so that the receiving device may determine the duration of the packet.

Abstract: This disclosure provides systems, methods, and apparatus, including computer programs encoded on computer-readable media, for implementing a hybrid automatic repeat request (HARQ) protocol in a wireless local area network (WLAN). A first WLAN device may transmit a first HARQ frame to a second WLAN device. The first HARQ frame may include initial transmissions of a first plurality of forward error correction (FEC) codewords. The HARQ protocol may support new techniques for feedback, such as a feedback capability in which a bitmap may be used to indicate decoding failures of codewords. The first feedback message may include indicators to change a HARQ configuration parameter based on channel conditions. In some implementations, the second HARQ frame may combine retransmissions regarding the failed codewords with initial transmissions of a second plurality of codewords.

Abstract: This disclosure provides methods, devices and systems of wireless communication in accordance with hybrid automatic repeat request (HARQ) techniques. Some implementations more specifically relate to aligning aggregate medium access control (MAC) protocol data unit (A-MPDU) subframes with codeword boundaries in a physical-layer service data unit (PSDU). The alignment may be performed by selectively adding padding bits to the PSDU based on the size of each A-MPDU subframe and the lengths of the codewords. In some aspects, an A-MPDU subframe may be aligned with a first codeword of the PSDU so that the first A-MPDU subframe is encoded exclusively within the first codeword. In some other aspects, an A-MPDU subframe may be aligned with two or more contiguous codewords of the PSDU so that the two or more contiguous codewords include the A-MPDU subframe and no portions of any other A-MPDU subframe.

Abstract: This disclosure provides systems, methods, and apparatus, including computer programs encoded on computer-readable media, for implementing a hybrid automatic repeat request (HARQ) protocol in a wireless local area network (WLAN). In some aspects, a first WLAN device may transmit a first HARQ frame to a second WLAN device. The first WLAN device may receive a first feedback message from the second WLAN device. The first feedback message may be a HARQ Block Acknowledgement (H-BA) message. The first WLAN device may determine to enable the HARQ protocol based on the first feedback message. The first WLAN device may receive an indication of an amount of memory available at the second WLAN device for processing HARQ transmissions. The first WLAN device may transmit a second HARQ frame to the second WLAN device based, at least in part, on the amount of memory available at the second WLAN device for processing HARQ transmissions.

Abstract: This disclosure provides systems, methods, and apparatus, including computer programs encoded on computer-readable media, for implementing a hybrid automatic repeat request (HARQ) protocol in a wireless local area network (WLAN). In some aspects, a first WLAN device may transmit a first HARQ frame to a second WLAN device. The first WLAN device may determine whether a first feedback message received from the second WLAN device includes HARQ acknowledgement information or non-HARQ acknowledgment information. The first feedback message may be a HARQ Block Acknowledgement (H-BA) message having a multi-station Block ACK (M-BA) frame format that includes HARQ acknowledgment information. The first WLAN device may transmit a second HARQ frame to the second WLAN device in response to determining the first feedback message includes the HARQ acknowledgment information. The first WLAN device may transmit a non-HARQ frame in response to determining the first feedback message includes non-HARQ acknowledgement information.

Abstract: Methods, devices, and computer program products for improving training field design in packets with increased symbol durations are disclosed. In one aspect, a method of transmitting a packet on a wireless communication network is disclosed. The method includes transmitting a preamble of the packet over one or more space-time-streams, the preamble including one or more training fields configured to be used for channel estimation, the one or more training fields each comprising one or more symbols of a first symbol duration. The method further includes transmitting a payload of the packet over the one or more space-time-streams, the payload comprising one or more symbols of a second symbol duration, the second symbol duration greater than the first symbol duration.