Research On Integer-Forcing Detection Algorithm In MIMO Systems

Multiple-Input Multiple-Output(MIMO)technology is one of the important technologies for wireless communication to enhance channel capacity and improve communication quality.Wireless channel fading,time varying and other characteristics require the MIMO system to correctly estimate the transmit signal from the receive signal experiencing fading and noise superposition.Therefore,the detection algorithm is particularly important and directly affects the system performance.At the same time,there is a tradeoff between the computational complexity and the performance at the receiver.For the above-mentioned problems,the thesis starts from the MIMO system channel model and selects the optimal detection algorithm that can achieve a good tradeoff between the complexity and the performance based on detailed theoretical analysis.The work of the thesis can be divided into following sections:Firstly,several classic detection algorithms are introduced,such as maximum likelihood detection and linear detection.Focusing on the Integer-Forcing detection,starting from system model and analyzing the key issues and solutions for it,such as using lattice reduction algorithm to find the equivalent integer channel matrix.Secondly,Generalized Spatial Modulation system as a branch of the MIMO system also has a tradeoff between the computational complexity and the performance.Therefore,the thesis proposes two improved algorithms based on Integer Forcing detection and are suitable for Generalized Spatial Modulation systems,linear detection estimate transmitting antenna number Integer-Forcing detection estimate symbols and Integer-Forcing detection of full search of transmitting antennas respectively.At the same time,the performance and complexity of the two algorithms are compared and analyzed.The complexity of former is low;the latter can achieve similar performance to maximum likelihood,which provides a good detection algorithm for the Generalized Spatial Modulation system.Finally,combining the space-time coding that can obtain transmitting diversity gains with Integer-Forcing detection that can achieve receive diversity.The multi-user space-time coding system has the high decoding complexity.In order to reduce the system decoding complexity and ensure better system performance,the Integer-Forcing detection algorithm with low complexity is used in multi-user space-time coding and the upper bound of error probability of Integer-Forcing detection is obtained based on the principle of equivalent noise power minimization.In order to solve the design of multi-user space-time coding for Integer detection,a design criterion of full diversity multiuser space-time coding based on Integer-Forcing detection is proposed and it is proved that each user's space-time coding scheme satisfies non-zero singular value property,The multi-user space-time coding can full-diversity gain.