Downlink MU-MIMO Precoding Technology Research And Link Level DSP Implementation Of LTE-A System

As the subsequent evolution of LTE, LTE-A has been seen as one of the mainstream technology of4G and its design has been far beyond the minimum requirements of4G. However, for the users of the same cell of LTE-A system, the signal receives by each user will be subject to interference from other user’s signals and seriously affect the quality of calling. The precoding technique can solve the problem of inter-user interference in the downlink MU-MIMO system, and thus it has become a research hotspot. In this paper, the LTE-A system downlink MU-MIMO precoding techniques were divided into linear precoding and non-linear precoding techniques. Linear precoding techniques were deeply studied and DSP implementiaon had been done.Firstly, non-linear precoding techniques were studied. The precoding technique of DPC, VP and THP were mainly focused. According to comparatively analysis three algorithms and take into account the complexity, simulation analysis of ZF-THP and MMSE-THP were made and the result was the performance of MMSE-THP is better.Secondly, some related research were made on linear precoding techniques. Such techniques as MMSE, BD and R-BDSVD were mainly focused on. Obtained by simulation analysis, the performance of R-BDSVD was superior to the other two precoding algorithms. R-BDSVD was improved as R-BDGMD and the simulation result proved the overall performance of R-BDGMD was better than R-BDSVD.Thirdly, DSP implementation of R-BDGMD was also made.Through optimization and multi-core parallel processing, the processing was finished in less than lms.The verification platform was built and was used to verify the correctness of the result.Finally, DSP implementation for the entire system had also been done. The graph of constellation and bit error rate displayed by the interface well proved the actual performance of the the R-BDGMD, and the result was also in line with actual situation.