| LTE is the project conducted by3GPP to deal with mobile broadband. The aim, ultimately, is to provide users with services with high data rate and reliability.As the key technology in LTE physical layer, multiple input multiple output (MIMO) and orthogonal frequency division multiplexing (OFDM) can dramatically improve the effectiveness and reliability of the system. By adopting multi-antenna MIMO can provide diversity gain and multiplexing gain, which can improve the efficiency and reliability of the system respectively. Precoding has become a research focus in LTE system as it can reduce the interference and processing complexity of the receiver effectively.At the beginning of the thesis, we investigate the MIMO precoding technique in physical downlink shared channel of LTE, focusing on the precoding scheme based on codebook and non-codebook and their performance. The precoding scheme based on codebook includes single antenna, transmit diversity and spatial multiplexing, while the approaches based on non-codebook are comprised of non-zero-forcing (ZF) algorithm, the minimum mean square error (MMSE), the algorithm based on singular value (SVD) and the one based on geometric mean (GMD) respectively. Then on the basis of V6LX240T chip in Flying4000platform, precoding modules related with codebook scheme are implemented including CPRI serial module, layer mapping module, precoding module and MMSE codebook selection module. Further, optimized structure of FPGA is provided which satisfies the higher operating frequencies in the case of conserving resources as far as possible. Finally, outputs of each module are obtained by using Modelsim simulation, and the correctness of each module functions are verified by comparing simulation results with fixed simulation. Sypilify is used to integrate each module, giving the maximum operating frequency and the results of resource consumption and the correctness of this design is verified by using Chipscope. |
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