A Physical-layer Rateless Code for Wireless Channels

TL;DR

This paper introduces a novel physical-layer rateless coding scheme for wireless channels that improves error performance and robustness across various SNRs, outperforming existing codes especially at low BER levels.

Contribution

A new rateless encoding scheme with equal symbol protection and an EXIT chart-based optimization for check node degree distribution, achieving near-capacity performance.

Findings

Significantly better BER performance than existing rateless codes.

Robust check node degree distribution optimized for various SNRs.

Effective in AWGN channels with low error floors.

Abstract

In this paper, we propose a physical-layer rateless code for wireless channels. A novel rateless encoding scheme is developed to overcome the high error floor problem caused by the low-density generator matrix (LDGM)-like encoding scheme in conventional rateless codes. This is achieved by providing each symbol with approximately equal protection in the encoding process. An extrinsic information transfer (EXIT) chart based optimization approach is proposed to obtain a robust check node degree distribution, which can achieve near-capacity performances for a wide range of signal to noise ratios (SNR). Simulation results show that, under the same channel conditions and transmission overheads, the bit-error-rate (BER) performance of the proposed scheme considerably outperforms the existing rateless codes in additive white Gaussian noise (AWGN) channels, particularly at low BER regions.