Research Of Channel Estimation And Symbol Detection Algorithms Under The Wireless Communication

As the key technologies of LTE (Long Term Evolution, LTE), MIMO and OFDM have become the main focus in the communication field. So, the channel estimation and symbol detection have taken the important role. In MIMO system, in order to improve transmission efficiency, we need to use the complex coding and modulation technology that may lead to the higher complexity of the symbol detection at the receiver. So, it is necessary to research the moderate complexity symbol detection algorithm to improve the practical value. While the channel information can be used directly by the receiver. So, the channel estimation algorithm is very important at the receiver. Therefore, the complexity and accuracy of channel estimation algorithms directly affect the performance of the wireless communication system. It is necessary to ensure the algorithms owning the high accuracy as well as the low complexity so that they can be applied to the real wireless system.This paper focuses on the research of symbol detection for the MIMO system and channel estimation for the OFDM system. Firstly, the paper introduces the principle of MIMO system, and analyzes three common algorithms ZF、 MMSE and ML. Because of the higher bit error rate of ZF and MMSE, and the high complexity of the ML algorithm, we proposed ZF-SIC and MMSE-SIC algorithm. In order to improve system performance, and reduce the massive calculation of traditional method of SNR-based ordering, the paper uses the ascending order of column norm to sort and detect undetected symbols. Secondly, in the channel estimation part, the paper introduces the basic principle of OFDM technology and some basics that related channel estimation at first, In the channel estimation of block-type pilot, the paper briefly analyses of the performance of LS and MMSE channel estimation algorithm. Then, LMMSE algorithm is proposed to reduce the computational complexity because of the high complexity of MMSE algorithm, In the channel estimation of no-block-type pilot, the IDFT transform is induced in the LS algorithm so that the reduction of matrix dimension can reduce the complexity. In addition, the spline interpolation is added to improve the performance of the system, the algorithm can achieve the tradeoff between computational complexity and accuracy.