Optimized Mapping Schemes for LDPC Coded Higher Order Modulated QAM Transmission

Abstract

Abstract. Low Density Parity Check (LDPC) codes are considered to be used in many future communication systems. We will show in this work how the performance of a communication system is influenced when different bit to symbol mapping schemes of a higher order modulation (e.g.: 16-QAM) are combined with LDPC coding. To evaluate and optimize bit-to-symbol mapping methods, a modified version of density evolution is proposed. In addition, simulation results are shown which justify the use of density evolution as a method for qualitative analysis of different symbol mapping schemes in conjunction with LDPC coding. We propose novel mapping methods and show performance results in combination with LDPC coding.

Performance Analysis of a Bit Mapper of the Dual-Polarized MIMO DVB-T2 System

“…2.2. DVB-T2 시스템의 비트 매퍼 비정규 LDPC 부호가 256-QAM과 같은 고차 변[13] , 반대 로 높은 SNR 환경에서는 큰 VND 값을 갖는 비트 들을 낮은 변조 레벨에 매핑해야 한다[14] . LDPC 부호화, 비트 매핑 및 성상 변조를 수행하기 위해 DVB-T2 표준 를 수행할 수 있다.…”