Systems and methods are disclosed herein relating to rate-compatible polar codes and the use thereof in a wireless communications system. In some embodiments, a transmit node operable for use in a wireless communications system comprises a rate-compatible polar encoder operable to encode information bits to provide coded bits utilizing parallel concatenated polar codes. The transmit node further comprises a transmitter operable to transmit the plurality of coded bits. In this manner, the transmit node may, in some embodiments, use polar codes having different coding rates to adapt to time-varying channel conditions.

A node (110, 115) receives (804) transmissions associated with a given set of information bits, wherein each of the transmissions use a different polar code and share one or more information bits of the given set of information bits. The node determines (808), at each of a plurality of polar decoders (505, 605) of the node, soft information for each information bit included in an associated one of the transmissions, wherein each of the plurality of polar decoders is associated with a different transmission of the transmissions. The node provides (812), from each polar decoder of the plurality to one or more other polar decoders of the plurality, the determined soft information for any information bits shared by their respective associated transmissions, and uses (816) the provided soft information in an iterative decoding process to decode one or more of the received transmissions.

Method and apparatus for transmission and reception with polar codes are provided to support up to 16 permutations or transformation mappings. For example, 16 versions of copies able to be soft-combined for PBCH or any other data channel or control channel are suggested if the mother code length is 256 or 512 or 1024. With the new design, up to 16 different versions can be used to soft combined to improve the performance. Some sequences are provided as examples to support 16 different permutation patterns. The inverse of these sequences also have the feature to support 16 different permutation patterns.

Apparatus and methods are provided for polar code sub-block interleaving and bit selection. In one novel aspect, middle-part interlaced sub-block interleaving is provided for polar code interleaving. In one embodiment, the middle part of the polar code is interlaced and generates the interleaved polar code. In another embodiment, the lower part and the upper part are also sub-block interleaved with the middle-part interlaced method. In another novel, rate-dependent unified bit selection is provided. The bit selection is categorized into three operation categories of repetition, puncturing and the shortening. Each category follows unified bit selection rule with different categories differ only in the access scheme. In one embodiment, the circular buffer is used for bit selection.

The present disclosure describes various examples of a method, an apparatus, and a computer-readable medium for wireless communications (e.g., 5G NR) using hybrid automatic repeat request (HARQ). For example, one of the methods includes generating a first codeword based on a first code block length, transmitting a first signal using the first codeword, generating a second codeword with incremental redundancy information based on a second code block length, generating a third codeword with repetition of at least a portion of the first codeword based on a third code block length, and transmitting a second signal using at least the second codeword or the third codeword.

A communication device includes: an encoder that encodes an input vector to output a codeword of Polar Code; a memory configured to store a frozen set of positions of frozen bits and a puncturing set of positions of punctured bits; and at least one processor configured to execute a set of instructions to: a) set the frozen set such that a punctured bit has a constant value; b) select the position of a punctured bit such that a minimum number of indices get frozen; c) freeze an index that has a highest decoding error probability among a plurality of indices selected according to the step b); d) repeat the steps b) and c) a predetermined number of times to obtain an array of indices; and e) perform a bit-reversal permutation of the array obtained in the step d) to generate the positions of the punctured bits in the puncturing set.

A node (110, 115) receives (804) transmissions associated with a given set of information bits, wherein each of the transmissions use a different polar code and share one or more information bits of the given set of information bits. The node determines (808), at each of a plurality of polar decoders (505, 605) of the node, soft information for each information bit included in an associated one of the transmissions, wherein each of the plurality of polar decoders is associated with a different transmission of the transmissions. The node provides (812), from each polar decoder of the plurality to one or more other polar decoders of the plurality, the determined soft information for any information bits shared by their respective associated transmissions, and uses (816) the provided soft information in an iterative decoding process to decode one or more of the received transmissions.

Systems, methods, and instrumentalities are disclosed for interleaving coded bits. A wireless transmit/receive unit (WTRU) may generate a plurality of polar encoded bits using polar encoding. The WTRU may divide the plurality of polar encoded bits into sub-blocks of equal size in a sequential manner. The WTRU may apply sub-block wise interleaving to the sub-blocks using an interleaver pattern. The sub-blocks associated with a subset of the sub-blocks may be interleaved, and sub-blocks associated with another subset of the sub-blocks may not be interleaved. The sub-block wise interleaving may include applying interleaving across the sub-blocks without interleaving bits associated with each of the sub-blocks. The WTRU may concatenate bits from each of the interleaved sub-blocks to generate interleaved bits, and store the interleaved bits associated with the interleaved sub-blocks in a circular buffer. The WTRU may select a plurality of bits for transmission from the interleaved bits.

Encoder for encoding K information bits into a code word of length N on the basis of a polar code of length N, wherein N is a power of 2 and greater than or equal to N. The encoder comprises a memory storing a plurality of bit indices, wherein the plurality of bit indices comprise a set of N frozen bit indices associated with the polar code of length N, a set of N/2 puncturing bit indices and/or a set of N/2 shortening bit indices and a processor configured to retrieve at least a subset of the plurality of bit indices from the memory, to encode the K information bits using the polar code of length N for obtaining encoded data of length N and to reduce the number of bits of the encoded data to the length N for obtaining the code word of length N.

This application provides a coding method, a decoding method, and a communications apparatus. The coding method includes: obtaining a first information bit sequence; determining a first frozen bit sequence based on a probability distribution value P.sub.1 of the first information bit sequence; determining a check bit sequence based on a second information bit sequence, where the second information bit sequence is the first information bit sequence or a sequence obtained after a pre-transformation operation is performed on the first information bit sequence; obtaining a first bit sequence based on the second information bit sequence, the check bit sequence, and the first frozen bit sequence, where the first bit sequence includes bits in the second information bit sequence.