Modified Min Sum Algorithm for Next Generation Satellite Broadcasting System: ABS-S

Abstract

The Advanced Broadcasting System for Satellite (ABS - S) is a new satellite TV and sound broadcasting system. In comparison to Digital Video Broadcasting (DVB - S2) it offers same performance but with lower complexity for future satellite digital broadcasting. The system are employed with Low-Density Parity-Check (LDPC) codes which offers channel capacity close to the shannon’s limit with iterative probabilistic decoding algorithm. For decoding with LDPC codes, sum product and min sum algorithms are used. This paper presents and overview of ABS - S system and a modified min sum algorithm (MMS) for decoding. The proposed algorithm is based on computation of sub - minimum value and a correction factor ^ which is based on minimum and sub - minimum value of extrinsic information. We achieved improvement of BER performance with short block length LDPC by applying correction factor ^ to messages sent from check node to bit node. Simulation results shows that the modified min sum algorithm performs better as compared to the MS algorithm and Sum Product (SP) algorithm with a reasonable complexity.