Chennel Estimation Study Based On LTE System

In order to meet the opportunities and challenges brought by the rapid development of the mobile communication market, the major telecommunication companies start a new competition with each other for core patents when 3G standardization has already finalized. The above contributes to the startup and development of 3GPP LTE. Comparing with the former mobile communication systems, LTE makes some important breakthrough at the capacity, the latency, the peak speed and the frequency spectrum flexibility, and recently many derivable topics have become the research focus in the communication filed.The study of channel estimation technology based on LTE made in this paper specifically refers to the design of the channel estimation schemes which are feasible and optimal. That is done on the premise of understanding the correlative LTE physical layer protocol well, and according to the LTE uplink and downlink characteristic as well as combining with existing channel estimation technology.When the LTE downlink channel estimation algorithm is studied, two schemes based on traditional channel estimation methods (i.e. LS algorithm and DFT-based channel estimation algorithm) are first designed. Then a theoretical analysis of these schemes'performance is made, and in order to overcome the disadvantages of each of them, two improved algorithms are proposed. Finally, the performance of all the designed downlink channel estimation schemes is validated and analyzed through simulation. The simulation results indicate that both the improved algorithms have good estimation performance as well as low complexity, so the two algorithms are more appropriate schemes of LTE downlink channel estimation.When the LTE uplink channel estimation algorithm is studied, the differences and relations between the uplink and downlink channel estimation algorithm are first analyzed, based on which, the feasibility of three kinds of typical channel estimation algorithms is evaluated, and the most reasonable LTE uplink channel estimation scheme is designed. Then the multi-user signal separation algorithm in MU-MIMO scenario is analyzed theoretically. Subsequently LMMSE filtering algorithm is proposed so as to improve the performance of channel estimation, which can be considered as a complement to the LTE uplink channel estimation scheme. At the same time, a feasible suboptimal LMMSE filtering method is proposed for practical application. The simulation results show that the design of the LTE uplink channel estimation scheme, namely LS algorithm with LMMSE filtering method (optional) and linear interpolation, is confirmative to LTE uplink practice and could meet the performance requirements of LTE uplink, so it is suitable for uplink DFT-S-OFDM system.At the end, a summary of the paper is made, and the prospects of further study in the future are also put forward.