The Research Of MIMO Scheme And The Detection Algorithm In LTE

Multiple-Input Multiple-OutPu(tMIMO)is one of the key technologies in LTE systems.Take advantage of random fading and multipath propagation to increase space transmission rate and transmission reliability is the most significant advantage of MIMO.The LTE downlink MIMO transmit model is analyzed in this paper, focusing on analysis of transmit diversity and spatial multiplexing in the program. Transmit diversity introduces some common diversity programs and compare the simulation performance of STBC and SFBC. Spatial multiplexing based on whether the feedback is divided into open and closed loop spatial multiplexing .The LTE spatial multiplexing and different code of the selection criteria are analyzed in this paper,.and verified significant improvements spatial multiplexing technology in system throughput and the appropriate selection criteria by simulationIn addition, another difficulty is that MIMO detection techniques, with the increase in the number of antennas and the use of higher order modulation, signal detection error rate and time complexity are severely restricted the performance of the system. Signal detection for spatial multiplexing is focused in this paper.First,several common techniques is theoretical analyszed, including maximum likelihood algorithm (ML), zero forcing detection algorithm (ZF), minimum mean square error detection algorithm (MMSE ), interference cancellation algorithm (SIC), the sphere decoding (SD),The performance and complexity of sphere decoding algorithm are analyzed in this paper. It can be knowed that the complexity sphere decoding for the whole range of SNR is not instability and the complexity under high the condition number(CN) is high . On this basis, a improved method for initial radius set is proposed and its validity is verified by simulation.