於上行傳輸多點協調系統中利用高效率干擾校齊之收發器設計

Abstract

由於鄰近細胞所造成的干擾會嚴重降低在現今無線細胞通訊系統中非常重要的系統效能，因此干擾必須被謹慎地處理。為了解決這個問題，第三代合作夥伴專案(third generation partnership project; 3GPP)在前瞻長程演進系統(Long Term Evolution-Advanced; LTE-A)中提出新穎的多點協調(coordinated multipoint; CoMP)傳輸與接收技術。在本篇論文中，吾人嘗試於上行傳輸多點協調系統中引入干擾校齊(interference alignment; IA)技術進而提升總傳輸速率。為了加快收斂速度，吾人進一步提出兩種高效率的干擾校齊演算法。其一為區塊QR分解輔助干擾校齊(block QR decomposition aided IA; BQRD aided IA)，它引入序列式干擾消除(successive interference cancellation; SIC)的概念。另一為兩階段式干擾校齊(two-stage IA)，它則是最佳化等效通道的結構並且引入功率載荷(power loading)。經由模擬驗證，吾人所提出的兩種演算法有較佳的收斂特性並且擁有和最大信號雜訊干擾比(signal-to-interference-plus-noise ratio; SINR)干擾校齊相近的總傳輸速率。由於僅需要較少迭代次數即可收斂，吾人提出的演算法更適合於實際應用。

The interference from other cells, which severely degrades the system performance, is a critical factor in modern wireless cellular communication systems and should be carefully managed. To tackle this problem, a new coordinated multipoint (CoMP) transmission and reception technique is proposed by the 3GPP in the LTE-A system. In this thesis, we attempt to incorporate interference alignment (IA) into uplink CoMP systems to improve the sum-rate performance. To boost convergence rate, we further propose two efficient IA aided transceiver designs for the uplink CoMP systems. One is the block QR decomposition (BQRD) aided IA that incorporates the concept of successive interference (SIC). The other is the two-stage IA that optimizes the structure of the effective channel and employs power loading. From simulation results, the proposed algorithms exhibit better convergence behavior and have comparable performance to the max-SINR IA. Requiring only a small number of iterations to converge, the proposed algorithms are suitable to practical applications.