On the performance of LDPC-coded OFDM system with periodically terminated differential phase modulation

In this paper, we consider the problem of symbol detection in a differentially encoded orthogonal frequency division multiplexing (OFDM) system over frequency selective fading channel. We first propose the periodical termination of differential phase trellis at predetermined indices. When the sequential Monte Carlo (SMC) methodology is applied to symbol detection in the proposed system, it is seen that accelerated weight degeneracy and impoverished trajectory diversity-problems that are encountered in conventional SMC methods-are mitigated. Furthermore, the terminated indices may also act as pilots, thus enabling pilot-aided SMC detection. Using these observations, we then propose a pilot-aided SMC detector that circumvents resampling. The effect of varying termination periods on the performance of the non-resampling detector is investigated. We also consider a low-density parity check (LDPC)-coded OFDM system and simulation results suggest the near bound performance of the proposed pilot-aided non-resampling SMC detector.