發(fā)布時間：2018-07-10 02:46

  本文選題：協(xié)作通信 + 分布式空時編碼��； 參考：《天津大學》2014年博士論文

【摘要】：無線通信系統(tǒng)中，為了進一步提高傳輸速率和傳輸可靠性，研究者們提出了協(xié)作通信技術。其基本思想是：網(wǎng)絡中每個節(jié)點向目的節(jié)點發(fā)送信息的同時，作為中繼幫助其他節(jié)點轉發(fā)信息。通過節(jié)點間共享彼此的天線，組成虛擬的多輸入多輸出(MIMO)系統(tǒng)以獲得空間分集增益，進而提高系統(tǒng)性能。協(xié)作通信技術可以有效增加分集增益，擴大網(wǎng)絡覆蓋范圍并降低終端發(fā)射功率，得到了工業(yè)界和學術界的廣泛關注，并有望成為第四代移動通信系統(tǒng)的關鍵技術之一。 本文針對協(xié)作通信系統(tǒng)中的分布式空時編碼技術及其檢測技術展開研究，重點解決非同步協(xié)作通信系統(tǒng)中碼間干擾（ISI）估計和消除問題，，以及半雙工中繼網(wǎng)絡中的滿速率傳輸問題： 首先，針對非同步協(xié)作通信系統(tǒng)中的ISI問題，提出了基于非相干檢測的ISI估計和消除算法。該算法使用分布式差分空時編碼技術，在目的節(jié)點不知道任何信道狀態(tài)信息（CSI）和定時誤差信息的情況下，實現(xiàn)ISI的消除，并獲得較好的誤碼率性能。該算法計算復雜度低，對碼字速率影響小，并有效解決了傳統(tǒng)ISI消除方案中CSI估計復雜度高，實現(xiàn)難度大的問題。 接著，本文研究了具有滿碼字傳輸速率半雙工中繼傳輸方案的誤符號率，重點分析了兩通路連續(xù)中繼（TPSR）方案和滿速率傳統(tǒng)中繼方案。文中給出了上述兩種方案的誤符號率，進一步分析：滿速率傳統(tǒng)中繼方案在調制階數(shù)很低的情況下性能略優(yōu)于TPSR方案，而調制階數(shù)較高時，TPSR方案性能更優(yōu)。即TPSR方案適用于高速無線網(wǎng)絡。 最后，針對TPSR網(wǎng)絡引起的中繼間干擾（IRI）問題，提出了兩種IRI消除方案：部分IRI消除方案和基于信號空間分集（SSD）編碼的差分傳輸方案。部分IRI消除方案中，目的節(jié)點保留部分IRI信號作為碼字符號的副本，在譯碼過程中加以利用以提高系統(tǒng)性能。同時，針對這一方案譯碼復雜度較高的問題，提出迭代最大比合并譯碼算法，并給出了相應的分集增益分析和性能仿真。結果表明，部分IRI消除方案可獲得額外分集增益并有效降低誤符號率。最后，本文提出了基于SSD編碼的差分傳輸方案以解決基于AF中繼的TPSR網(wǎng)絡中CSI估計復雜度高的問題。該方案中，目的節(jié)點無需知道任何CSI，而中繼節(jié)點僅需估計中繼間信道，即可有效消除IRI并對接收信號進行非相干譯碼，具有較低的計算復雜度和CSI估計復雜度。
[Abstract]:In order to further improve the transmission rate and transmission reliability in wireless communication systems, researchers proposed cooperative communication technology. The basic idea is that while each node in the network sends information to the destination node, it helps other nodes to forward the information as a relay. By sharing each other's antennas among nodes, a virtual multiple-input multiple-output (MIMO) system is constructed to gain spatial diversity gain and improve system performance. Cooperative communication technology can effectively increase diversity gain, expand network coverage and reduce terminal transmission power. It has been widely concerned by industry and academia, and is expected to become one of the key technologies in the fourth generation mobile communication systems. In this paper, the distributed space-time coding technology and its detection technology in cooperative communication systems are studied, and the problem of ISI estimation and elimination in asynchronous cooperative communication systems is emphatically solved. And the full-rate transmission problem in half-duplex relay networks. Firstly, an ISI estimation and cancellation algorithm based on incoherent detection is proposed for the ISI problem in asynchronous cooperative communication systems. The algorithm uses distributed differential space-time coding (DSTC) to eliminate ISI and achieve better BER performance without knowing any channel state information (CSI) and timing error information. The algorithm has low computational complexity and little influence on codeword rate, and effectively solves the problem of high CSI estimation complexity and difficult implementation in the traditional ISI elimination scheme. Then, the symbol error rate of the half-duplex relay transmission scheme with full codeword transmission rate is studied, and the two-channel continuous relay (TPSR) scheme and the traditional full rate relay scheme are analyzed. In this paper, the symbol error rate of the two schemes is given, and further analyzed: the performance of the traditional full rate relay scheme is slightly better than that of the TPSR scheme when the modulation order is very low, but the performance of the TPSR scheme is better when the modulation order is higher. That is, TPSR scheme is suitable for high speed wireless network. Finally, aiming at the inter-relay interference (IRI) problem caused by TPSR network, two kinds of IRI cancellation schemes are proposed: partial IRI cancellation scheme and differential transmission scheme based on signal space diversity (SSD) coding. In the partial IRI cancellation scheme, the destination node retains part of the IRI signal as a copy of the codeword symbol and uses it in the decoding process to improve the system performance. At the same time, aiming at the high decoding complexity of this scheme, an iterative maximum ratio merge decoding algorithm is proposed, and the corresponding diversity gain analysis and performance simulation are given. The results show that the partial IRI elimination scheme can obtain additional diversity gain and reduce symbol error rate effectively. Finally, a differential transmission scheme based on SSD coding is proposed to solve the problem of high CSI estimation complexity in AF relay based TPSR networks. In this scheme, the destination node does not need to know any CSI, and the relay node only needs to estimate the inter-relay channel, which can effectively eliminate the IRI and decode the received signal incoherently, which has low computational complexity and CSI estimation complexity.
【學位授予單位】：天津大學
【學位級別】：博士
【學位授予年份】：2014
【分類號】：TN92

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本文編號：2111730