MIMO Signal Detection Technology VBLAST Coding

Multi-input multi-output technology as one of the core technologies of wirelesscommunication, the advantage of its core position is to rational use of multi-path fading,exponentially increase the capacity of the communication system without increasing thebandwidth conditions. Particularly with the improvement of material conditions, the number ofmobile users drastically increases, also the rapid development of multimedia services, MIMOtechnology can increase the transmission rate of the communication on the limited bandwidthresources, also can increase the reliability of information transmission, and therefore MIMO isacclaimed. However, to discover such a large potential of MIMO technology, the receiverdetection technology plays a key role. It is the communication purposes that the receiver cancorrectly recover the data information transmitted from the transmitter, while the complexity ofthe receiver is not too high. This paper describes the background of MIMO technology,development direction and research, and focuses on the MIMO signal receiver detectiontechnology, mainly including the following three aspects:(1)Insight into the basic concepts of MIMO technology and several kinds of classicaldetection technology of MIMO signal receiver, including ML，ZF，MMSE，SIC，and OSIC. Andtheoretical analysis of the performance of all detection methods, at the same time theexperimental simulation and theoretical analysis are consistent.(2)In this paper, we take the system bit error rate into consideration and propose animproved detection algorithm based on the estimation error in descending order. In the newalgorithm, all the constellation points in the constellation diagram will be regarded as theestimated value in the ifrst layer. The signal estimated value is divided into several parallelbranches, and carry on serial interference cancellation detection. According to the estimationerror in descending order，we can ensure the reliability of the back layer to increase gradually, andchoose the optimal as the ifnal detection output from the whole parallel branches. The simulationresults show that, compared with the unimproved algorithm, the complexity of the modiifedalgorithm increases slightly, while the bit error rate is lower, the overall performance is improved.(3)Owing to the radius has a greater impact on algorithm complexity in the sphere decodingalgorithm, propose an improved rapid contraction of the radius of the sphere decoding detectionalgorithm. The improved method determines the initial radius based on the MMSE algorithm.And other layers can quickly shrink radius by weighting coeiffcients. The simulation inMIMO-OFDM system results show that the complexity of the modiifed algorithm is lower thanthat of traditional sphere decoding，and different weighting coeiffcients have different impact onthe system performance and calculation. At the same time, we have got a suitable coeiffcient bysimulation. In a word, the computational complexity of the system reduces effectively only asmall performance loss.