The Comparison of Different Combining Techniques and the Selection Mechanism of Relay Nodes in Cooperative Communication System

Recently, the benefit due to spatial diversity has been drawn much attention; especially, thecooperative communication system is one of well known implementations, and which isdeveloped promptly. In such the system, a transmitted device is able to enjoy bettertransmission quality than in a conventional direct link system by means of the assistancefrom the relay nodes. In this work, we mainly discuss the effect of the multiple relay nodescooperative system with the AMC scheme; meanwhile, MRC, EGC, and Pre-MRC are takeninto consideration at the destination node to compare the performance amount differentcombining schemes. For the analyzing simplicity, we take the advantage of Gilbert channelinto this system to emulate the DF process at the relay node. Additionally, in order to achievehigher system efficiency, the selective partial cooperation is focused on, and the suitablerelay nodes are chosen, then the relay selection region is discussed under the Poisson pointenvironment for a mobility source. Finally, the theoretical and simulation results areconducted in this work, and also showing the improvement caused by this proposal.近期，空間多樣性的優勢受到許多重視，尤其地，其中一種著名的實現方式--合作通訊，亦是快速低發展。在該系統中，藉由其他傳播點的幫助，一個傳輸裝置可以比傳統的點對點傳輸享有更好的通訊品質。在此計畫中，我們主要將探討多傳播點在適應性調變技術中對於該系統效能的效應，同時在目的接收端，將針對多種不同結合技術對於系統效能作比較，其中包括了最大比例結合，等增益結合，以及事先加權最大比例結合。為了簡化分析，我們將引入吉爾伯通道來描述傳播點的解碼傳播行為。另外，為了達到更好的系統效率，我們亦將著眼於部份選擇的合作通訊系統，其中較為適合的傳播點將會被選出。對於一個移動的來源點，我們將於卜瓦松節點環境中探討傳播點的選擇區域。最後，我們將會呈現理論值以及模擬結果，並顯示出此計畫對於該系統的改善