水声通信系统中分布式空时分组码的研究

协作传输可以获得无线信道内在的空间分集,有效改善通信系统的性能,增加通信系统的覆盖范围。对水声通信系统中两中继节点协作的译码转发方案进行了研究,提出了基于译码转发协议(DF)的分布式空时分组扩频编码(DSTBSC)方案,该方案可以克服多径衰落对分布式空时分组码(DSTBC)信号正交性的影响。给出了DSTBSC方案的系统模型,着重分析了在采用两中继译码转发时,中继节点的误码对水声通信系统性能的影响。在接收端不考虑信号冲突的情况进行仿真,结果表明,与直接传输方案相比,采用两中继节点、译码转发的DSTBSC方案,在两中继节点处均无误码和一个中继有误码时在相同的比特误码率(BER)条件下均可获得约4dB的分集增益,增加了传输距离。

Research on distributed space-time block coding (DSTBC) in underwater acoustic communication system

Cooperative transmission can obtain spatial diversity inherent in wireless channel, improve performances of communication system effectively, and increase the coverage of communication systems. In this paper, the cooperative diversity scheme of two relay nodes decoding forward （2relay-DF） in underwater acoustic communication system has been studied. Based on decoding forward （DF） protocol, the distributed space-time block spreading code （DSTBSC） scheme is proposed. This scheme can overcome the influence of multipath fading on the orthogonality of DSTBC signal. This paper presents a system model of DSTBSC scheme, mainly analyzes the effect of decoding error on the system performance of 2relay-DF. Signal conflict at the receiving end is not considered in the simulation of this work. Simula- tions show that, compared with the direct transmission scheme, the DSTBSC decoding forwarding scheme with two relay nodes can get about 4dB diversity gain and increase the transmission distance in the same BER condition when no decoding error exists at the two relay nodes or the decoding error exists only at one of the two relay nodes.