基于多级码编码正交频分复用的差分幅度相位调制

数字调幅广播(DAMB)需要高速的数据传输率,为此本文提出一种具有高带宽效率的编码调制方案。采用16差分幅度相位(16DAPSK)加正交频分复用(OFDM)调制,采用多级码(MLC)作为纠错编码,其分量码为标准卷积码及其删除型卷积码,系统具有高的带宽利用率,抗多径传输,接收端可以并行解码,以减小通常逐层解码所带来的大的时延和误差传播,并且由于差分调制的引入,接收端可以采用非相关检测,且毋须均衡器,简化了接收机的设计,本文还比较了短波信道中,采用时域差分和频域差分的效果,并得出了相应的结论。

MLC coded orthogonal frequency division multiplex using 16DAPSK modulation

Digital amplitude modulation broadcasting (DAMB) needs high data rate transmission, so a coded orthogonal frequency division multiplex (COFDM) plus 16DAPSK modulation scheme of high bandwidth efficiency is presented in this paper. In this scheme the standard convolutional code as the mother code and the punctured code from it is used in each level. A parallel decoding technique can be used due to the inherent bit interleaved property of MLC to reduce the latency and avoid error propagation of ordinary multistage decoding (MSD) and at the same time with the application of differential modulation a non-coherent detection can be used and no channel equalization is needed so the complexity of receiver designing is reduced consequently. The comparison between differentiating in time domain and in frequency domain is made and a conclusion is presented in the paper.