A Study Of LTE Uplink Channel Estimation And DSP Implementation

With the increase of demand on the multimedia services,3GPP has proposed its long term evolution(LTE)system.Compared with the 3G system,LTE can create amazing user experiences of the wireless network throughput.Today,LTE network has entered into a formal commercial stage.On the one hand,the most significant improvement of LTE system is that the new physical layer technology.So,in the base station side,the demodulation performance of LTE uplink receiver is facing new challenges.As the core technology of the uplink receiver--channel estimation,which is very important to study the algorithm performance.On the other hand,with the increase of LTE network users,telecom operators hope one cell can provide services for more users.In order to balance the shortage of network capacity and the increasing demand of network users.First,this thesis studies LTE PUSCH receiver technology,According to the protocol,learning the PUSCH receiver principle.Secondly,this thesis further studies the PUSCH channel estimation noise reduction algorithm principle and implementation in time domain.Study and propose a new channel estimation algorithm ―Frequency domain FIR noise filter channel estimation algorithm‖Frequency domain FIR noise filter channel estimation algorithm.In addition to the feasibility study,this thesis mainly solves 3 key problems.First,the selection of FIR filter of different modulation and channel mode.Because of the different modulation method has the different channel response characteristics,One design of FIR filter can not meet the performance requirements under various conditions.This thesis made a simulation based on a variety of modulation and channel conditions.Through the simulation result finally gives the selection of FIR filter,At the same time,the simulation result also shows that Frequency domain FIR noise filter channel estimation algorithm has better performance.Second,TA effect Frequency domain FIR noise filter channel estimation algorithm performance,because of the time domain characteristics of FIR filter window start with 0.when the received signal have TA.If do not synchronize.The filtering performance will be worse.In this thesis,we first do the TA compensation process to the received signal.When finished the channel estimation,recovery the TA.Third,the user separation of MU-MIMO.In the frequency domain,TA shows on the phase.So for multi users receive signal,the phase contained multiple users information,can not directly calculate.This requires that before the channel estimation,first we should separate the multiple users.Then,calculate the TA,and give the TA result.Last,this thesis based on the LTE PUSCH receiver DSP platform,Coded the Frequency domain FIR noise filter channel estimation algorithm in DSP,then test the CYCLEs.Give the CYCLE test results compared with the time domain noise reduction algorithm.Finally,considering the algorithm performance and the implementation cost,the Frequency domain FIR noise filter channel estimation algorithm proposed in this thesis,is the better channel estimation algorithm for the current commercial LTE system.