Serially Concatenated Doubly Differential PSK for Improved Noncoherent Iterative Detection(HISC2006)

概要

論文の詳細を見る
Serial concatenation of a convolutional encoder, a bit interleaver, and a recursive modulator provides strong protection against transmission errors and can be decoded iteratively. When used for transmission over channels introducing a random and potentially time varying phase rotation, noncoherent softinput soft-output demodulation must be used at the receiver. In many cases, however, noncoherent demodulation effectively removes the recursiveness of the modulator, thus harming the convergence of iterative decoding. In this paper we propose a serially concatenated system with doubly differential phase shift keyed (DDPSK) modulation employing a generator polynomial G(D)=1/(1-D^2). We demonstrate that this DDPSK system retains full recursiveness under noncoherent demodulation and hence assures good convergence behavior for iterative decoding. Also, by regarding such modulation as either doubly differential with generator polynomial G(D)=1/(1-D)(1+D), or as two parallel singly differential modulations with polynomial G(D)=1/(1-D) acting independently on odd and even symbols, we propose two distinct approaches to performing noncoherent demodulation of DDPSK. We demonstrate good error performance and good iterative decoding convergence behavior by means of simulation and extrinsic information transfer (EXIT) charts.
社団法人電子情報通信学会の論文
2006-05-18