於多用戶多輸入多輸出系統中利用差動量化降低通道回饋量

Abstract

現代無線通訊系統中，有限回饋是近幾年備受關注的關鍵技術之一。在有限的回饋頻寬之下，如何有效量化通道資訊是系統設計的重要議題。在本篇論文中，吾人著重在基於不影響系統效能或甚至提昇系統效能的前提下降低通道回饋量。吾人提出兩種方法：第一，針對回傳通道狀態資訊，吾人提出向量差動量化。第二；對於空間相關性矩陣的回傳，吾人提出對角向量量化向量。差動量化在接收端引進預測性向量量化技術，進而利用通道的時間相關性壓縮通道回饋量；對角向量量化則主要是利用空間上的相關性來達到減少量化位元數。模擬結果顯示吾人提出的方法能較現有方法達到更好的性能表現。

Limited feedback techniques have drawn attention for many years and emerged as one of the key techniques in modern wireless communication systems. Under the finite-rate feedback link environment, the issue of how to quantize channel information efficiently becomes important for system design. In this thesis, we focus on reducing the required feedback rate while maintaining or even enhancing the performance of the overall system. We propose two methods: one is differential vector quantization (VQ) for channel state information (CSI) feedback, and the other is diagonal-wise full VQ for spatial correlation matrix feedback. The proposed differential VQ introduces Predictive Vector Quantization (PVQ) in the receiver end to compress the CSI by exploiting the temporal correlation of the channel. The diagonal-wise full VQ mainly exploits the spatial correlation of the channel to reduce the feedback quantization bits. Simulation results indicate that both methods can achieve a higher SINR and a smaller MSE compared to the existing schemes.