Nonbinary LDPC Coded OFDM
Shengli Zhou, Zhaohui Wang · 2014
Channel coding is an integral part of a digital communication system. This chapter discusses two basic formats of coupling channel coding with OFDM modulation. It then focuses on nonbinary low-density-parity-check (LDPC) codes. Channel coding is introduced to protect information bits from errors after transmission through communication channels, and the bit-to-symbol mapping are used to increase the transmission spectral efficiency. The chapter talks about several channel coding schemes widely used in OFDM systems. The performance of nonbinary LDPC codes depends on various factors. In general, the larger the field size and the larger the block length, the better is the performance for nonbinary LDPC codes. Encoding of a general LDPC code can be done in almost linear time instead of quadratic time on the block length. Decoding of LDPC codes can use standard sum-product algorithms (SPA) and its low-complexity variants. The chapter presents some Monte Carlo simulation results of coded OFDM.