A-Performance-Improved-Iterative-Channel-Code-Decoder-For-High-Order-Modulation-Signals-

A method of log-likelihood ratio (LLR) generation for input to channel code decoder is presented in this paper. It will be demonstrated that, in a communication system where iterative channel decoding, namely turbo and low density parity check (LDPC) codes, and high order modulations, such as 8PSK, 16QAM and 64QAM, are used, the input to channel code decoder can be iteratively updated by using intermediate results of the decoder for better performance. This technique is applicable to 3G wireless systems, for example 3GPP and 3GPP2, and WiMax (IEEE 802.16)