Abstract:

A low-density parity check code (LDPC) decoding algorithm which takes the reliability as information metric is firstly described. Secondly, a low complexity soft demodulating algorithm for CPM is proposed. The new demodulating algorithm is independent of variance of noise, which avoids the effect of uncertain estimation of the channel. Finally, a low complexity joint iterative decoding algorithm is proposed, which also takes the symbol/bit reliability as the information metric between inner decoding and outer decoding. The algorithm is simple and easy to apply. Simulation results show that the new demodulating algorithm performs as well as the probabilistic demodulating algorithm; compaing with the decoding algorithm without iterations, the joint iterative decoding algorithm has about 0.75 dB gain, with equal total local iterations.