【摘要】：MIMO技術極大地促進了無線通信的發(fā)展，，在TD-LTE-Advanced系統(tǒng)中也得到了廣泛的應用，下行最多可以支持8層傳輸，上行最高支持4層傳輸，并且定義了多達9種多天線傳輸模式。除MIMO傳輸技術外，自適應技術是TD-LTE-Advanced系統(tǒng)采用的另一項關鍵技術，eNodeB根據(jù)UE反饋的CSI信息，為用戶選擇合適的調制編碼方式、合理的傳輸模式以及預編碼矩陣等等，進而更好的適應移動通信的復雜信道變化。然而，這兩項關鍵技術能否完全發(fā)揮其作用的關鍵因素是系統(tǒng)CSI反饋機制的有效性和可靠性。因此，本文對多天線傳輸模式下TD-LTE-Advanced系統(tǒng)的反饋機制進行了深入的研究。 本文首先研究了TD-LTE-Advanced系統(tǒng)的預編碼技術和MIMO檢測算法。針對預編碼技術，本文依次研究了基于碼本的預編碼和波束賦形技術，并重點對常用的多用戶波束賦形算法進行了仿真分析，經比較，基于SLNR的波束賦形算法能夠有效地降低用戶間干擾，從而具有更好的性能。之后本文對MIMO檢測算法展開研究，并對常用算法進行了仿真分析，通過對檢測性能及復雜度的綜合比較，選用MMSE算法作為本文接收機的檢測算法。在上述研究的基礎上，本文又針對不同場景，給出了多小區(qū)多天線傳輸下的SINR的計算公式。 然后，本文對TD-LTE-Advanced標準中規(guī)定的9種反饋模式進行了歸納、總結和比較，并在本文搭建的TD-LTE-Advanced的系統(tǒng)級仿真平臺上，對與MIMO傳輸相關的多種反饋模式的性能進行了仿真評估，分析了各種反饋模式的適用性。在此基礎上，本文提出了一種提升小區(qū)邊緣用戶性能的反饋模式切換算法，仿真結果顯示，采用此切換算法后，在僅增加極小反饋開銷的條件下，小區(qū)邊緣用戶的吞吐量得到了有效的提升。 最后，本文利用TD-LTE-Advanced系統(tǒng)上下行信道的互易性，針對慢變信道和快變信道場景，分別提出了CQI頻域修正方案和結合信道預測的CQI時頻聯(lián)合修正方案。仿真結果表明，采用本文所提的CQI修正方案可以有效降低系統(tǒng)初始重傳率，并提高系統(tǒng)吞吐量。此外，采用CQI修正方案后，使用寬帶CQI反饋模式可以獲得與子帶CQI反饋模式近似甚至更優(yōu)的性能，從而大大降低了反饋開銷。
[Abstract]:MIMO technology has greatly promoted the development of wireless communication and has been widely used in TD-LTE-Advanced systems. Downlink can support up to 8 layers of transmission, uplink can support up to 4 layers of transmission, and up to nine kinds of multi-antenna transmission modes are defined. In addition to MIMO transmission technology, adaptive technology is another key technology used in TD-LTE-Advanced system. ENodeB selects appropriate modulation and coding mode, reasonable transmission mode and precoding matrix for users according to the CSI information fed back by UE. And then better adapt to the complex channel changes of mobile communication. However, the key factor of whether these two key technologies can fully play their role is the effectiveness and reliability of the system CSI feedback mechanism. Therefore, the feedback mechanism of TD-LTE-Advanced system in multi-antenna transmission mode is deeply studied in this paper. In this paper, the precoding technology and MIMO detection algorithm of TD-LTE-Advanced system are studied. Aiming at precoding technology, this paper studies the precoding and beamforming technology based on code book in turn, and focuses on the simulation and analysis of common multi-user beamforming algorithms. The beamforming algorithm based on SLNR can effectively reduce the interference between users, so it has better performance. After that, this paper studies the MIMO detection algorithm, and carries on the simulation analysis to the common algorithm. Through the comprehensive comparison of the detection performance and complexity, the MMSE algorithm is selected as the detection algorithm of the receiver in this paper. On the basis of the above research, the calculation formula of SINR under multi-cell and multi-antenna transmission is given in this paper according to different scenarios. Then, this paper summarizes, summarizes and compares the nine feedback modes specified in TD-LTE-Advanced standard, and on the system-level simulation platform of TD-LTE-Advanced built in this paper, The performance of various feedback modes related to MIMO transmission is simulated and evaluated, and the applicability of various feedback modes is analyzed. On this basis, this paper proposes a feedback mode switching algorithm to improve the performance of cell edge users. The simulation results show that when the switching algorithm is adopted, only the minimum feedback overhead is increased. The throughput of cell edge users has been effectively improved. Finally, based on the reciprocity of uplink and downlink channels in TD-LTE-Advanced system, a CQI frequency domain correction scheme and a CQI time-frequency joint correction scheme combined with channel prediction are proposed for slow and fast variable channel scenarios, respectively. The simulation results show that the CQI correction scheme proposed in this paper can effectively reduce the initial retransmission rate and improve the system throughput. In addition, after the CQI correction scheme is adopted, the performance of the broadband CQI feedback mode can be approximately or even better than that of the subband CQI feedback mode, thus greatly reducing the feedback overhead.
【學位授予單位】：哈爾濱工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TN929.5

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1 孫垂強;葛建華;朱斌;李靜;;匹配加權信號泄漏噪聲比多用戶預編碼迭代算法[J];西安電子科技大學學報;2013年04期

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