| Summary: | 碩士 === 國立清華大學 === 通訊工程研究所 === 106 === To support the higher data rate in the next generation mobile communication system, massive multiple-input multiple-output (MIMO) systems has attracted a lot of attentions for the past few years. The disadvantage of massive MIMO systems is high power consumption, since large amount of RF chains should be deployed. Hence, hybrid precoding architecture, which splits the traditional baseband precoder into a RF precoder and baseband prcoder, is proposed to implement massive MIMO systems with small amount of RF chains much less than the number of antennas. In this work, the designs of RF precoder are classified into two categories. The one is not to take singular value decomposition (SVD) for channel matrix, since the computational complexity is very high in massive MIMO systems. Therefore, we will choose several bases from a pre-defined codebook as RF precoder, because the angle of departure (AOD) and angle of arrival (AOA) of the propagation paths are assumed to be unknown. The other approach is to take SVD for channel matrix and extract the phase of the optimal precoder as RF precoder which can form a multiple beam pattern. Baseband precoder and combiner are used to avoid inter-stream interference which most of researches ignores. Our methods can achieve an interference-free effect at the receiver. As a result, we can get a better performance than other researches if interference is considered.
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