MIMO-OFDM 系統中到達角度，離開角度以及通道之聯合估 計:一個壓縮偵測的作法

Abstract

使用天線陣列形成波束已被認為是在未來的5G通信系統中很有潛力的技術。然而，為了使用波束形成的技術，接收機必須知道信號的到達角度（AoAs），和發射機的離開角度（AoDs）。傳統角度估計的方法往往需要較高的計算複雜度。在本論文中，提出了新的方法來解決這個問題。首先，提出一種壓縮偵測的聯合估計方法來估計在單輸入多輸出OFDM系統中的到達角度和通道響應。然後，該演算法被擴展到聯合估計在廣義的多輸入多輸出OFDM系統中的到達角度、離開角度、以及通道響應。到達角度、離開角度、以及通道響應的Cramer-Rao lower bounds (CRLBs)也在這篇論文中推導。模擬結果顯示，本論文中提出的方法在訊雜比高的時候可以趨近CRLB。論文中所提出的方法有良好的性能，且計算複雜度低。

Beamforming with Antenna array has been considered as a potential technique in future 5G communication systems. To conduct beamforming, however, the receiver has to know the signal angle-of-arrivals (AoAs), and the transmitter the angle-of- departures (AoDs). Conventional methods for the estimations often require high computational complexity. In this thesis, new methods are proposed to solve the problem. First, a compressive-sensing based joint estimation method is proposed to estimate the AoA and channel response in single-input-multiple-output OFDM systems with the frequency-domain pilots. Then, the algorithm is extended to the joint estimation of the AoA, AoD, and channel response in general multiple-input -multiple-output OFDM systems. The Cramer-Rao lower bounds (CRLBs) for the AoA, AoD, and channel response are also derived. Simulations show that the proposed methods can approach the CRLB when signal-to-noise ratio is high. Despite the good performance, the computational complexity of the proposed methods is low.