LTE-A系統之場域內多使用者協調式多點傳送：一個基於天線選擇的方法

Abstract

在傳統蜂巢式網路的系統中，細胞邊緣的使用者容易受到鄰近細胞的干擾，為了解決這個問題，LTE-A系統提出協調式多點傳送與接收(CoMP)的技術來盡量減少細胞之間的干擾。另外，近年來多使用者系統多輸入多輸出(MU-MIMO)技術已發展成熟，此技術可以讓多個使用者在同一時間以及同一頻率上傳輸資料，有效地提高系統的效能。有鑑於此，LTE-A系統試著將MU-MIMO與CoMP這兩項技術作整合，期望能夠達到更好的峰值速率以及頻譜使用效率。本論文旨在探討場域內CoMP的多使用者聯合處理技術，我們提出了基於天線選擇的新的聯合處理方法，由於多了天線選擇這個自由度，使得系統資源可以更有效的運用，除此之外，天線選擇可以幫助我們將多傳送點的問題簡化為一個虛擬的單傳送點問題，因此使得現有單傳送點多使用者的技術可以直接應用。模擬結果顯示，我們所提出的方法可能比傳統的作法在更少的資訊回報量之下，提供更好的系統吞吐量。

In conventional cellular network systems, the cell edge users are vulnerable to interference from neighboring cells. In order to deal with this problem, coordinate multipoint transmission/reception(CoMP) has been proposed in LTE-A system. Yet, in recent years, multiuser multiple- input-multiple output (MU-MIMO) has been well developed. The MU-MIMO technique allows the simultaneous transmission of multiple user signals in the same time at the same frequency band, and hence enhances the system performance effectively. Thus, LTE-A tries to integrate MU-MIMO and CoMP hoping for better peak data rate and higher spectrum efficiency. This thesis aims to investigate intra-site MU CoMP joint processing (JP) techniques. We propose a new antenna-selection-based JP method that can better use the system resource and reduce the feedback overhead. Thanks to the antenna selection technique, we can translate a multipoint CoMP problem to a virtual single-point CoMP problem such that the existing single-point MU-MIMO technique can be directly applied. Numerical results show that the proposed method outperforms the conventional approach and at the same time requires less feedback overhead.