Flexible IR-HARQ scheme for polar-coded modulation

Abstract

A flexible incremental redundancy hybrid automated repeat request (IR-HARQ) scheme for polar codes is proposed based on dynamically frozen bits and the quasi-uniform puncturing (QUP) algorithm. The length of each transmission is not restricted to a power of two. It is applicable for the binary input additive white Gaussian noise (biAWGN) channel as well as higher-order modulation. Simulation results show that this scheme has similar performance as directly designed polar codes with QUP and outperforms LTE-turbo and 5G-LDPC codes with IR-HARQ.

Throughput-Based Design for Polar-Coded Modulation

“…In this scheme, a family of L polar codes of lengths N 1 < N 2 < ... < N L are designed for a fixed message word of K bits. By using quasi-uniform puncturing [24] along with careful repetition of message bits at the encoder and some minor modifications to the polar decoder (see [23] for details), these codes are rate-comparable. The throughout-maximizing design technique presented here can easily be extended to this IR scheme.…”

“…IR schemes have the additional advantages that each retransmission does not have to be of the same length, and can belong to an extended code instead of merely repeating code bits. A very good incremental redundancy scheme based on punctured polar codes was recently proposed in [23]. In this scheme, a family of L polar codes of lengths N 1 < N 2 < ... < N L are designed for a fixed message word of K bits.…”