Research On Channel Esitmaiton Techniques For TD-LTE Downlink Physical Layer

This thesis introduced the structure of TD-LTE physical layer, principles of OFDM technology, and focuses on the research of channel estimation technology of TD-LTE physical layer.Based on the study and analysis of the TD-LTE downlink physical layer and the traditional OFDM channel estimation technology, this paper proposed a channel estimation technique based on Turbo iteration. Different from the traditional channel estimation, the new channel estimation algorithm makes the channel estimator and decoder running simultaneously. Thanks to the good error correction capability of Turbo encoding, this algorithm can improve the performance of the channel estimation effectively. Secondly, based on the study of channel receiving terminal decoding process of TD-LTE downlink physical layer, and according to the different of decoding order PDCCH channel and PDSCH channel region, a channel estimation technique based on the control domain is proposed. Compared with the traditional channel estimation technique, this algorithm can provide more accurate channel estimation performance by using more additional virtual pilot information.At last, based on the study of compressive sensing channel estimation, this thesis proposes an adaptive pilot channel estimation algorithm. The proposed algorithm can estimate the channel sparsity when the channel sparsity is unknown, and adjusted the pilot density of channel estimation. According to the different channel environments, the number and mode of pilot can be effectively designed to reduce unnecessary pilot overhead.