Abstract: Certain aspects of the present disclosure generally relate to techniques for enhanced puncturing and low-density parity-check (LDPC) code structure. A method for wireless communications by a transmitting device is provided. The method generally includes encoding a set of information bits based on a LDPC code to produce a code word, the LDPC code defined by a base matrix having a first number of variable nodes and a second number of check nodes; puncturing the code word according to a puncturing pattern designed to puncture bits corresponding to at least two of the variable nodes to produce a punctured code word; adding at least one additional parity bit for the at least two punctured variable nodes; and transmitting the punctured code word.

Abstract: Methods, systems, and devices for encoding and decoding are described. To encode a vector, an encoder allocates information bits of the vector to channel instances of a channel that are separated into groups. The groups may vary in size and allocation of the information bits is based on a base sequence of a given length. During decoding, a decoder assigns different bit types to channels instances by dividing a codeword into a plurality of groups and assigning bit types to channel instances of the plurality of groups using the base sequence.

Abstract: Methods, systems, and devices are described for wireless communication. A transmitter may receive feedback that a station failed to decode a packet sent over a first channel, and the transmitter may determine to re-send the packet or to send parity bits over the first channel or over a second channel to assist in decoding the failed packet. The first channel may be in an unlicensed radio frequency spectrum, and the second channel may be in a licensed radio frequency spectrum and may have a higher reliability level compared to the first channel. The transmitter may determine a first channel degradation level, which may be based on a signal-to-noise ratio received from the station, and may determine an amount of parity bits to send based on the degradation. The transmitter may determine the reliability level of each channel, which may be based on a channel quality indicator.

Abstract: Certain aspects of the present disclosure generally relate to techniques for puncturing of structured low-density parity-check (LDPC) codes. Certain aspects of the present disclosure generally relate to methods and apparatus for a high-performance, flexible, and compact LDPC code. Certain aspects can enable LDPC code designs to support large ranges of rates, blocklengths, and granularity, while being capable of fine incremental redundancy hybrid automatic repeat request (IR-HARQ) extension while maintaining good floor performance, a high-level of parallelism to deliver high throughout performance, and a low description complexity.

Abstract: Certain aspects of the present disclosure generally relate to techniques for puncturing of structured low density parity check (LDPC) codes. A method for wireless communications by wireless node is provided. The method generally includes encoding a set of information bits based on a LDPC code to produce a code word, the LDPC code defined by a matrix having a first number of variable nodes and a second number of check nodes, puncturing the code word to produce a punctured code word, wherein the puncturing is performed according to a first puncturing pattern designed to puncture bits corresponding to one or more of the variable nodes having a certain degree of connectivity to the check nodes, and transmitting the punctured code word.

Abstract: A wireless device (e.g., a base station or user equipment (UE)) may encode a codeword using a polar code for transmission over a wireless channel. The device may identify a set of bit locations of the polar code for a set of information bits based on a bit index reliability sequence. The bit index reliability sequence may be based on applying an ordered combination of a universal partial order, an analytical method, and a simulation. The bit index reliability sequence may be determined based on a binary bit weighting for the set of bit channels that applies one or more weighting factors. In some cases, the device may store the bit index reliability sequence in a lookup table for encoding, decoding, or both. A device receiving the transmitted codeword may similarly utilize the bit index reliability sequence to decode the codeword and determine the transmitted information bits.

Abstract: Certain aspects of the present disclosure relate to techniques and apparatus for improving decoding latency and performance of Polar codes. An exemplary method generally includes generating a codeword by encoding information bits using a first code of length K to obtain bits for transmission via K channels, wherein the first code comprises a polar code, further encoding the bits in each of the K channels using a second code of length M, and transmitting the codeword.

Abstract: Certain aspects of the present disclosure generally relate to techniques for puncturing of structured low density parity check (LDPC) codes. A method for wireless communications by wireless node is provided. The method generally includes encoding a set of information bits based on a LDPC code to produce a code word, the LDPC code defined by a matrix having a first number of variable nodes and a second number of check nodes, puncturing the code word to produce a punctured code word, wherein the puncturing is performed according to a first puncturing pattern designed to puncture bits corresponding to one or more of the variable nodes having a certain degree of connectivity to the check nodes, and transmitting the punctured code word.

Abstract: Various aspects described herein relate to techniques for rate matching and interleaving in wireless communications (e.g., 5G NR). In an example, a method described herein includes encoding one or more information bits to generate a first codeblock, rate matching the first codeblock to generate a second codeblock, segmenting, using bit distribution, the second codeblock into one or more sub-blocks each having a plurality of bits. The method further includes interleaving the plurality of bits on each of the one or more sub-blocks, concatenating, using bit collection, the one or more sub-blocks to generate a third codeblock in response to the interleaving, and transmitting a signal using the third codeblock.

Abstract: Methods, systems, and devices for wireless communication are described. In some examples, a wireless device (e.g., a user equipment (UE) or a base station) may encode a codeword from a set of information bits using an LDPC code. The wireless device may then transmit multiple versions of the codeword to improve the chances of the codeword being received. In some aspects, the wireless device may use the techniques herein to generate self-decodable redundancy versions of the codeword to be transmitted to the receiving device. Accordingly, a receiving device may be able to identify information bits from one or more redundancy versions of the codeword even if the receiving device failed to receive an original transmission of the codeword.

Abstract: An apparatus are provided for wireless communication at a base station with improved PBCH construction and decoding. The base station apparatus constructs a PBCH payload, wherein a bit location is selected for encoding a plurality of bits of the PBCH based on an estimated reliability for the corresponding bits location wherein the plurality of bits comprises frozen bits, unknown bits that are unknown to a user equipment, and potentially known bits that are potentially known by the user equipment. The apparatus transmits the PBCH payload in at least one of a plurality of SS blocks. A UE receiving the PBCH decodes the PBCH based on a successive decoding order. The successive decoding order may be based on an estimated reliability for the corresponding bits, e.g., in which potentially known bits are decoded prior to unknown bits.

Abstract: Aspects of the disclosure relate to polar coding. A polar codeword may be generated by sorting a plurality of synthetic channels utilized for transmission of the polar codeword over an air interface in order of reliability utilizing a convex combination of the mutual information calculated for each synthetic channel based on an Additive White Gaussian Noise (AWGN) channel and the mutual information calculated for each synthetic channel based on a binary erasure channel. A polar codeword may further be generated by sorting the plurality of synthetic channels in order of reliability utilizing cumulative sums calculated for each synthetic channel. Each cumulative sum may be calculated from a binary representation of a position of the synthetic channel within the plurality of synthetic channels.

Abstract: Certain aspects of the present disclosure relate to techniques and apparatus for improving decoding latency and performance of Polar codes. An exemplary method generally includes generating a codeword by encoding information bits, using a multi-dimensional interpretation of a polar code of length N, determining, based on one or more criteria, a plurality of locations within the codeword to insert error correction codes generating the error correction codes based on corresponding portions of the information bits, inserting the error correction codes at the determined plurality of locations, and transmitting the codeword. Other aspects, embodiments, and features are also claimed and described.

Abstract: Aspects of the present disclosure relate to low density parity check (LDPC) coding utilizing LDPC base graphs. Two or more LDPC base graphs may be maintained that are associated with different ranges of overlapping information block lengths. A particular LDPC base graph may be selected for an information block based on the information block length of the information block. Additional metrics that may be considered when selecting the LDPC base graph may include the code rate utilized to encode the information block and/or the lift size applied to each LDPC base graph to produce the information block length of the information block.

Abstract: Methods, systems, and devices for encoding and decoding are described. To encode a vector, an encoder allocates information bits of the vector to channel instances of a channel that are separated into groups. The groups may vary in size and allocation of the information bits is based on a base sequence of a given length. During decoding, a decoder assigns different bit types to channels instances by dividing a codeword into a plurality of groups and assigning bit types to channel instances of the plurality of groups using the base sequence.

Abstract: Aspects of the disclosure relate to a sidelink signal communication scheme that provides for rapid adaptation of the sidelink transmission based on feedback received during each transmission time interval (TTI). In this way, any lack of precision in interference measurements, or rapid changes in the amount of interference, which otherwise might cause a modulation and coding scheme (MCS) that was selected for the sidelink transmission to be unsuitable, may be adapted to improve the reliability of the transmission. Other aspects, embodiments, and features are also claimed and described.

Abstract: Certain aspects of the present disclosure generally relate to techniques for compactly describing lifted low-density parity-check (LDPC) codes. A method by a transmitting device generally includes selecting a first lifting size value and a first set of lifting values; generating a first lifted LDPC code by applying the first set of lifting values to interconnect edges in copies of a parity check matrix (PCM) having a first number of variable nodes and a second number of check nodes; determining a second set of lifting values for generating a second lifted LDPC code for a second lifting size value based on the first lifted PCM and the first set of lifting values; encoding a set of information bits based the first lifted LDPC code or the second lifted LDPC code to produce a code word; and transmitting the code word.

Abstract: An apparatus is provided for wireless communication at a base station with improved PBCH construction and decoding. The base station apparatus constructs a PBCH payload, wherein a bit location is selected for encoding a plurality of bits of the PBCH based on an estimated reliability for the corresponding bits location wherein the plurality of bits comprises frozen bits, unknown bits that are unknown to a user equipment, and potentially known bits that are potentially known by the user equipment. The apparatus transmits the PBCH payload in at least one of a plurality of SS blocks. A UE receiving the PBCH decodes the PBCH based on a successive decoding order. The successive decoding order may be based on an estimated reliability for the corresponding bits, e.g., in which potentially known bits are decoded prior to unknown bits.

Abstract: Aspects of the present disclosure relate to low density parity check (LDPC) coding utilizing LDPC base graphs. Two or more LDPC base graphs may be maintained that are associated with different ranges of overlapping information block lengths. A particular LDPC base graph may be selected for an information block based on the information block length of the information block. Additional metrics that may be considered when selecting the LDPC base graph may include the code rate utilized to encode the information block and/or the lift size applied to each LDPC base graph to produce the information block length of the information block.

Abstract: Various aspects of the disclosure relate to encoding information and decoding information. In some aspects, the disclosure relates to an encoder and a decoder for Polar codes with HARQ. If a first transmission of the encoder fails, information bits associated with a lower quality channel may be retransmitted. At the decoder, the resulting decoded retransmitted bits may be used to decode the first transmission by substituting the retransmitted bits for the original corresponding (low quality channel) bits. In some aspects, to decode the first transmission, soft-combining is applied to the decoded retransmitted bits and the original corresponding (low quality channel) bits. In some aspects, CRC bits for a first transmission may be split between a first subset of bits and a second subset of bits. In this case, the second subset of bits and the associated CRC bits may be used for a second transmission (e.g., a retransmission).