Exploiting cooperative multipath –Doppler diversity in relay-assisted high-speed train communications  

作　　者：Xiqian Luo Zhaoyang Zhang Caijun Zhong Xinyu Jin 

机构地区：[1]Department of Information Science and Electronic Engineering,Zhejiang University

出　　处：《Chinese Science Bulletin》2014年第35期5019-5028,共10页

基　　金：supported in part by the National Key Basic Research Program of China(2012CB316104);National Hi-Tech R&D Program(2014AA01A702);Zhejiang Provincial Natural Science Foundation of China(LR12F01002);the National Natural Science Foundation of China(61371094)

摘　　要：Severe doubly selective channel fading,or the time- and frequency-selective fading,prevailing in highspeed train(HST) communications,has been a critical issue that hinders the improvement of system efficiency and reliability.In this paper,a relay-assisted HST communication system is considered,and a low-complexity but effective scheme is proposed to cooperatively exploit the joint multipath–Doppler diversity of both the direct link and the relay link and thus to mitigate the negative effect of channel fading and improve the system reliability.In particular,using a special precoding structure followed by two-dimensional Fourier transform,the transmit signal is generated which in effect parallelizes the doubly selective fading channel.As a result,in the transform domain,pointwise combining and equalization,which are of linear complexity,become feasible and diversity gain is obtained.The maximal diversity order is then analyzed under the amplify-and-forward relay settings,which reveals that by cooperative relaying the joint multipath–Doppler diversity of both links can be well exploited.Simulation results verified our analysis.Severe doubly selective channel fading, or the time- and frequency-selective fading, prevailing in high- speed train （HST） communications, has been a critical issue that hinders the improvement of system efficiency and reli- ability. In this paper, a relay-assisted HST communication system is considered, and a low-complexity but effective scheme is proposed to cooperatively exploit the joint mul- tipath-Doppler diversity of both the direct link and the relay link and thus to mitigate the negative effect of channel fading and improve the system reliability. In particular, using a special precoding structure followed by two-dimensional Fourier transform, the transmit signal is generated which in effect parallelizes the doubly selective fading channel. As a result, in the transform domain, pointwise combining and equalization, which are of linear complexity, become feasi- ble and diversity gain is obtained. The maximal diversity order is then analyzed under the amplify-and-forward relay settings, which reveals that by cooperative relaying the joint multipath-Doppler diversity of both links can be well exploited. Simulation results verified our analysis.

关 键 词：通信系统 高速列车 多普勒 多样性 继电器 频率选择性衰落 二维傅立叶变换 中继链路 

分 类 号：TN929.5[电子电信—通信与信息系统]