Optimized Mapping Schemes for LDPC Coded Higher Order Modulated QAM Transmission

摘要

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.