Research On Precoding Technology In MIMO System

In order to solve the problem of signal interference, and reduce the processing complexity of the user side, the transmission signal needs to be processed in advance at the transmitter. Therefore, effective precoding scheme plays a vital role on the transmission performance of mobile communication system.In this paper, we mainly study for the precoding technique in MIMO system, and design the adaptive pre encoding scheme by using the appropriate selection criteria and decision threshold. When the state of the application scene changes, it can change the pre encoding program, to maintain the stability of the system performance.According to the number of users to receive the number of users, MIMO pre encoding program can be divided into single-user pre encoding and multi-user pre encoding, and according to the sending end of pre encoding processing mode, it can be divided into Linear pre encoding technology and Nonlinear pre encoding technology. First of all, the SU-MIMO pre encoding program is discussed and analyzed, including Linear pre encoding technology and Nonlinear pre encoding technology for single user, and the traditional TH nonlinear pre coding technology is improved. Then the MU-MIMO pre encoding technology is discussed and analyzed, Including linear pre encoding technology: Pre encoding based on ZF guidelines, pre encoding based on MMSE guidelines, BD pre encoding; Nonlinear pre encoding technology: QR-TH pre encoding based on ZF criteria, QR-TH pre encoding based on MMSE criteria, and design ZF-BD-GMD-TH pre encoding.At last, according to the condition of system operation, the adaptive pre encoding scheme is designed. The scheme uses appropriate pre encoding technique according to the mobile client speed, terminal performance, load conditions and other conditions, and can change the pre encoding program through the user side of the environment regularly updated, and ensure the reliability of MIMO system.