The Research Of The Multiple Symbol Differential Detection Algorithms For Cooperative System

In order to solve the terminal equipment for MIMO system limited by thevolume、hardware complexity and restriction for power consumption, when thesystem achieves spatial diversity effect, a new space technology—cooperativetechnology was proposed. In the process of cooperative technology, not only thecooperative approach of sending signal, but the detection method of receiving signalcan diversify. For cooperative approach of sending signal, the performance of threebasic cooperative strategies in the system are AF、DF and CC. On the BERperformance DF is the best, while AF is the worst. At the same time on theperformance of complexity AF is the least, while DF is the most. CC is in the middleof AF and DF on the spect of both BER performance and complexity. For detectionmethod, to avoid the difficulty of channel estimation, differential detectionscheme was proposed, which is more suitable for practical applicationenvironment. However, it also brings a3dB performance loss compared tocoherent detection, so mutilpe-symbol differential detection was proposed to narrowthe3dB performance gap.However, utilizing multiple-symbol differential detection will bring highcomputational complexity. We proposed three detection algorithms for differentcooperative systems to solve this problem. The three detection algorithms canachieve a compromise between BER performance and complicated computational.At the same time, on the basis of three cooperative strategies and the reseach fordetection algorithm in this paper, we focus on AF and CC cooperative strategies toavoid repeatability of the research.We focus on three multiple-symbol differentialdetection algorithms for cooperative system, base on AF and CC cooperativestrategies which is combined with different differential encodes respectively.First, multiple-sysmbol differential ML detection is proposed for distributedspace-time CC cooperative system to improve the performance of cooperativesystem by reducing the3dB loss of single-symbol differential detection. Second,because ML algorithm has a shortcoming of high computational complexity, we proposed multiple-symbol differential SD algorithm for orthogonal space-time AFcooperative system to reduce the space complexity of cooperative system. Finally,base on the current deficiency of the exiting SD algorithms, we proposemultiple-symbol differential PASD algorithm which is suitable to hardware in thefuture for unitary space-time AF cooperative system to achieve a compromisebetween BER performance and complexity. These three algorithms are derived bydetailed theoretical formula analysis and simulation test to verify the effective.