Precoding Technology In LTE System

To take challenges of development of 3G technology,HSDPA and EUL have been deployed to enhance the performance of 3G communication system.When these technologies is at the stage of implementation and testing,3GPP officially approved the plan of long term evoluation(LTE) to enhance the performance of UTRAN system and reduce the cost under the promotion of some large operaters.To meet the requirement of LTE system performace:high rates and large capacity,LTE system supports downlink MIMO.Beamforming is a technology of small antenna space which generate the strongest direction using the strong correlation of space channel. The radiation pattern main lobe points adaptively to the DOA of users to enhance to SINR and increase the system capacity.But the spatial multiplexing is a technology using the weak correlation of space channel,which transfers different data stream on different space channel to increase the peak date rate.At present,MIMO technology based on precoding has been widely used in the system among the system of E3G.As the requirement of user rate is rising,ITU forwards higher requirements of peak rate and spectrum efficiency of IMT-A.3GPP organizations have alse embarked on LTE system and proposed LTE-A system.In the LTE-A system,8 receive antennas are applied in the scenario of downlink MIMO.In the paper,the first few chapers introduce technologies of LTE and LTE-A system,such as OFDM,MIMO,etc.And in the later chapters,principle and simulation implemention of two precodeing and analysis the results and drew a conclusion.