本論文中，我們研究一個有限前傳鏈路容量(Finite fronthaul capacity)的上行鏈路雲端接取網路(Uplink cloud radio access network, Uplink C-RAN)架構，該網路架構包含一個半雙工、配備單天線之上行鏈路行動用戶(Uplink mobile user, UMU)，透過一個半雙工、配備單天線的遠程無線電頭(Remote radio head, RRH)，與中央基頻單元(Centralized baseband unit, BBU)溝通。本論文之目標是在行動用戶傳輸能量限制(User transmit power constraint)及前傳鏈路容量限制(Fronthaul capacity constraint)的約束下，將行動用戶的總和速率最大化(Sum rate maximization)。我們考慮該遠程無線電頭執行單用戶壓縮(Single-user compression)以量化(Quantize)收到的信號，並透過有限容量之前傳鏈路傳送量化位元(Quantization bits)到基頻單元。基頻單元使用最小均方誤差接收器(Minimum-mean square-error receiver, MMSE receiver)解碼(Decode)。在以上之設定及目標下，我們探討傳輸能量(Transmit power)及量化雜訊共變異數(Quantization noise covariance)的共同優化(Joint optimization)問題以最大化此網路的效用。我們使用權重均方誤差最小化連續凸近似演算法(Weighted Minimum-Mean-Square-Error Successive Convex Approximation algorithm, WMMSE-SCA algorithm)解總和速率最大化之優化問題。最後利用模擬結果分析此演算法。

In this thesis, we consider a uplink cloud radio access network (C-RAN) architecture with finite fronthaul capacity. The C-RAN includes a half-duplex, single-antenna uplink mobile user communicating with a centralized baseband unit (BBU) through a half-duplex, single-antenna remote radio head (RRH). Our goal is to maximize the sum rate of mobile user under user transmit power and fronthaul capacity constraints. We consider the RRH performs single-user compression to quantize the received signals and send the quantized bits to the BBU through fronthaul link with finite capacity. The BBU decodes the received signals with minimum-mean square-error receiver. Under the setup above and for maximizing the C-RAN utility, we investigate the joint optimization of the transmit power and the quantization noise covariance. Weighted Minimum-Mean-Square-Error Successive Convex Approximation (WMMSE-SCA) algorithm is used to solve the sum-rate maximization problem. Simulation results are presented to evaluate the algorithm.

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