用於無線多中繼OFDM系統下合作式MMSE接收機之設計與模擬

Design and Simulation of Cooperative MMSE Receiver for Wireless Multiple-Relays OFDM System

張書浩(Shu-Hao Chang)

指導教授 ： 鍾日龍

中原大學/工學院/電子工程研究所/碩士(2010年)

https://doi.org/10.6840/cycu201000556

摘要

近年來，合作式通訊(Cooperative Communication)的技術已証實可獲得合作分集(Cooperative Diversity)以改善和提昇整個系統鏈路品質。在本論文中，我們研究使用多中繼(relay)在頻率選擇通道(frequency-selective channel)下，採用最小均方誤差(MMSE)解調方式之合作式通訊技術OFDM接收機。此通訊系統採用半雙工(half-duplex)的放大傳遞(amplify-and-forward﹐AF)中繼協定。首先，傳送端將OFDM信號同時向目的端與中繼端傳送，接著，基於放大傳遞(amplify-and-forward﹐AF)協定，中繼端再將接收訊號放大傳送給目的端，最後，利用最小均方誤差(MMSE)將目的端的二路接收信號作結合。我們接著推展到兩根天線的合作式通訊OFDM接收機來比較系統的效能。模擬結果顯示合作式OFDM接收機可達到全分集增益(full diversity)。

關鍵字

合作式通訊 ； 最小均方誤差 ； 頻率選擇通道 ； 合作式分集增益

並列摘要

Recently, cooperative communication has drawn much attention because it can provide extra cooperative diversity gain to improve network quality. In this paper, we investigate the design of orthogonal-frequency-division multiplexing (OFDM) receiver for the multiple-relays system under the frequency-selective channels and derive the receiver solution in the minimum- mean-squared error (MMSE) sense. The communication network adopts half-duplex amplify-and-forward (AF) protocol. In this first phase, the source simultaneously sends OFDM signal to the destination and relays. In the second phase, the relays amplify the signals in accordance with the AF protocol and then send the signals to the destination. Finally, the two signals received at destination are combined with the MMSE. Extension to two antennas is also presented. Simulation results indicate cooperative communication OFDM receiver can obtain full diversity.

並列關鍵字

cooperative diversity ； frequency-selective channel ； amplify-and-forward ； cooperative communication

參考文獻

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