Research On Lattice-Reduction-Aided Detection Algorithm For MIMO Systems With High Order Modulation

In recent years, mobile communication services have gradually transformed to the high rate of multimedia video data from the single low speed speech data business. The transformation of the kind of demand makes the original spectrum resources become more nervous, which requires a higher quality of data transmission rate and communication service. Hence, the current problem to be solved is how to improve the spectrum efficiency to increase the data transfer rate. However, multiple input multiple output (MIMO) technology makes full use of multiplexing gain and space diversity gain to reduce bit error rate and achieve high data rate, thus improve the quality of communication. the technique is not at the cost of increasing transmission power and extra bandwidth. However, the application of the receiving end of the signal detection technology will directly affect the performance of the system, The design of the receiver in MIMO systems with high order modulation is the emphasis in this paper.On the basis of briefly describing the detection technology in MIMO systems with high order modulation, system model and channel capacity analysis, this thesis mainly studies the lattice reduction aided signal detection issues MIMO systems with high order modulation. Our research work can be summaried as follows:Firstly, analysed the multiplexing technology, channel model, system model and the signal detection algorithms in the MIMO systems with high order modulation, system detection technology has been more researched, mainly divided into three categories:the maximum likelihood algorithm, the linear detection algorithm and the nonlinear detection algorithm. They are unable to achieve great trade-off between detection performance and computational complexity based on the theoretical research of the traditional detection algorithm. To solve the above problems, we propose a lattice-reduction-aided detection algorithm GLLL on the basis of analyzing ELLL algorithm.Secondly, we propose an improved lattice-reduction-aided semi-definite relaxation (SDR) detection algorithm, it combined with the improved lattice reduction algorithm GLLL based on the traditional SDR detection algorithm, The channel matrix is preprocessed to obtain a more orthogonal matrix so as to improve the detection performance of the system. Simulation results show that the improved algorithms can achieve good balance between the detection performance and computational complexity in MIMO systems with high order modulation, which has good reference value and practical value.