Abstract:

In order to decrease the positive feedback in the iterative detection of the short frame Q-ary low density parity check (LDPC) code and the high-order continuous phase modulation (CPM) system, the combination average and weighted extrinsic information exchange for the low SNR, and the weighted extrinsic information exchange for the medium and high signal-to-noise ratio are proposed. In this information exchange, the extrinsic information between the demodulator and the decoder is correspondingly processed, which can control excessive fluctuations bit probability. Meanwhile, it performs decoding with two stopping criteria of dynamic iterative decoding: cross entropy (CE) and hard decision aided (HDA). Theoretical analysis and simulation results show that the combination of weighted extrinsic information exchange and the dynamic iterative stopping algorithm can not only resist the positive feedback effectively, and improve the convergence of iterative detection and the system bit error rate performance, but also reduce the average number of iterations, and keep the system in real-time.