合作式通訊傳輸架構在上傳系統下之探討

現今無線通訊系統中，多輸入多輸出技術為最受到大家注目的技術之一。利用多根天線傳接收在不增加頻寬和功率的情況下有效地改善整體系統效能。但以上傳機制而言，手持裝置(如手機、PDA等)因為受限於體積、費用等等限制，而其無法擁有多根天線傳輸，使得上傳無法達到與下傳機制同等效能。近年來，合作式通訊技術被許多人廣泛地探討與研究，利用多個手持裝置分享彼此的天線，透過互助合作的傳輸方式建立出一個虛擬多輸入多輸出系統。利用此概念可以增加傳輸通道的多樣性來對抗通道衰落的影響，進而提升整體系統效能。在本篇論文中，首先探討了不同類型的中繼站，分析彼此優缺點，並藉由模擬得出彼此的工作區間。接下來我們探討合作式通訊傳送架構，此架構包含了一台來源端、一台目的地端和數台中繼站。在探討的架構中，中繼站用來幫助來源端傳送資料。我們藉由分析以及模擬結果比較出不同傳送架構中彼此效能的差異。另外我們也探討含部份回授通道狀態資訊下對整體合作式通訊系統的影響。中繼站可利用回授資訊而採用不同的編碼訊號傳送，進而提升通道增益。系統也可藉由回授資訊排除一些所處環境較差的中繼站，而採用被選上的中繼站來幫助來源端傳送資訊。

關鍵字

多輸入多輸出；上傳系統；中繼站；合作式通訊傳送架構；部份回授通道狀態資訊

並列摘要

For the recent wireless communication system, Multiple Input Multiple Output technique is the one of the most popular techniques. In case of not increasing power and bandwidth, MIMO system can improve performance by multiple antennas transmit and receive signals. In the uplink system, the handset (as cell phone, PDA etc.) can not have multiple antennas to transmit due to the limitation of size, cost etc.. So that uplink system is unable to reach the same performance as downlink system. In recent years, cooperative communication has been studied from many researchers. It utilizes many handsets to share their antennas, and to create a virtual MIMO system through cooperative transmission scheme. This conception can increase transmitted channel diversity to combat fading, and then improves the performance of all systems. In this paper, first we study different kinds of relays, and get working space each other by simulating. Next we study cooperative communication transmission schemes. It includes one source, one destination, and many relays. In this scheme, relay help source transmit information. Trough analyzing and simulating, we compare the performance of each cooperative transmission schemes. In addition, we also study the effect of cooperative communication system with partial Channel Information Feedback (CSI). By partial CSI, not only relays can select different coding symbol to transmit to increase channel gain, but also system can select the relays with better environment to help source transmit source information.

並列關鍵字

MIMO ； uplink system ； relay ； cooperative communication ； partial CSI

參考文獻

[1] G. J. Foschini, “Layered Space-Time Architecture for Wireless Communications in a Fading Environment when using Multiple Antennas,” Bell Labs Tech. J., v.1, n.2, pp.41–59, 1996.

[2] A. Nosratinia etc, “Cooperative communication in wireless networks,” IEEE Communications Magazine, vol. 42, no. 10, pp. 74–80, October 2004.

[4] S. Yiu, R. Schober, and L. Lampe, “Distributed space-time block coding,” IEEE Transactions on Communications, vol. 54, no. 7, pp. 1195–1206, July 2006.

[5] J. N. Laneman and G. W. Wornell, “Distributed space time coded protocols for exploiting cooperative diversity in wireless networks,” IEEE Trans. Inform. Theory, vol. 49, no. 10, pp. 2415-2425, Oct. 2003.

[6] S.M. Alamouti. “A Simple Transmitter Diversity Scheme for Wireless Communications.” IEEE J. Select. Areas Commun. , 16:1451– 1458, October 1998.

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合作式通訊傳輸架構在上傳系統下之探討

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