Research On Predecoding And Layer Demapping And Implement In LTE System

Multiple input multiple output(MIMO) technology as one of the key technologies of LTE system, Had a strong advantage to improve spectrum efficiency. As the key technology of MIMO technology:precoding and layer mapping, sent in symbols mapping to the transmitted antenna. At the received terminal, used predecoding and layer demapping, made the received signals back to the original sent stream, balanced the affection by channel faded and noise that go through wireless channel.so, the LTE system predecoding and layer demapping technology has been researched.Firstly, studied the MIMO system model and characteristics, analyzed the capacity of MIMO system and precoding and layer mapping technology. Depended on the MIMO transmission mode, The precoding technology had different patterns, so for different patterns used different ways to achieve predecoding. For single antenna predecoding only need to division matrix; the transmit diversity decoder method based on the Solution of space-frequency coding because of it coding method was space-frequency coding;For spatial multiplexing solutions of predecoding combined the MIMO detection algorithms, made classic detection algorithm applied to the solution of predecoding. Accorded to the performance of detection and realization, the detection algorithm can be divided into: Maximum likelihood detection algorithm、zero Forced algorithm and the minimum mean square error algorithm、and interference elimination algorithm.Then,Set up a platform for the simulation, For a variety of algorithms were simulated, Analyzed and compared the difference of each algorithm on the detection performance. Accorded to the previously described, simulated by FPGA hardware simulation, Including solution of layer mapping and detection of prediction coding module,Accorded to the different way of MIMO transmission design implementation,including single antenna、transmit diversity and spatial multiplexing.