Design of LDGM-based Raptor Codes for broadband Internet of Things using EXIT chart

Abstract

Efficient channel coding techniques for wireless communications become important solutions to meet the 5G requirements, especially on the aspect of high reliability and low latency communications in the Internet of Things (IoT) era. This paper proposes new degree distributions of Raptor Codes for devices supporting IoT communications with Low Density Generator Matrix (LDGM) codes as the precode, called LDGM-Raptor codes. The proposed LDGM-Raptor codes is applied for broadband IoT (BB-IoT) to support high data rate in IoT networks with high reliability while keeping low computational complexity. The degree distribution in LDGM-Raptor codes is designed by using Extrinsic Information Transfer (EXIT) charts in Binary Erasure Channel (BEC)-based equivalent Additive White Gaussian Noise (AWGN) and multipath fading channels. EXIT charts are also used to estimate Bit-Error Rate (BER) performances of the proposed codes. The results confirm that the performance with new degree distributions of LDGM-Raptor close to the Shannon limit, which is required to make BB-IoT reliable and efficient.