解决移动场景下过时信道信息对OR-SAR的影响：一种简单放大转发策略

103 浏览量更新于2024-08-26 收藏 522KB PDF 举报

本文主要探讨了"基于过时信道状态信息的简单放大转发机会中继"这一前沿研究主题。在现代无线通信网络中，特别是那些依赖于协作通信的系统中，机会中继选择（Opportunistic Relay Selection, ORS）由于其低复杂性而受到青睐，它仅激活最合适的中继节点来协助数据传输。然而，移动通信环境中的一大挑战是，由于无线信道变化快速（相对而言），在进行中继选择时使用的信道状态信息（Channel State Information, CSI）可能与实际传输时的通道条件不一致，导致信道估计错误，进而影响到中继的选择，从而降低系统的整体性能。作者们关注的是这种"CSI过时"问题，他们提出了一种基于过时CSI的简单放大转发机会中继策略。研究者们在西安交通大学电子与信息工程学院和中国太原卫星发射中心合作，通过对现有技术的深入分析，试图找到一种解决方案，以减少因CSI更新不及时带来的负面影响。他们可能采用的方法包括改进的中继选择算法，该算法考虑了信道状态的老化程度，或者利用预测技术来尽可能准确地估计当前的信道条件，以便在有限的信息下做出更接近最优的决策。文章发表于2014年《中国科学：信息科学》卷57期，6月刊，第062301篇文章，涵盖了1-14页的内容。论文的DOI为10.1007/s11432-013-4951-1，表明这是一篇由科学中国出版社和柏林/海德尔堡Springer-Verlag联合出版的研究论文。研究团队在2013年9月17日接收了论文，并在同年12月4日接受并通过审稿，最终于2014年1月8日在线发布。这篇论文的目的是为了提高移动通信环境下机会中继系统的效率和可靠性，通过解决信道状态信息过时带来的问题，为未来的无线网络设计提供了理论支持和实践指导。

Wang C, et al. Sci China Inf Sci June 2014 Vol. 57 062301:3

2Systemmodel

The cooperative network presented in Figure 1 is considered in this paper, which is made up of a single

source node S, N relays, i.e., R

, 1  k  N and a single destination node D. All relay nodes operate

in the half-duplex AF mode. We suppose the channel coeﬃcient between any two nodes is quasi-static

Rayleigh fading. We model the channel coeﬃcients of two hops denoted by h

and h

respectively for

k =1,...,N as zero mean, independent, circular-symmetric complex Gaussian random variables with

variances σ

and σ

, i.e., h

∼CN



0,σ



, h

∼CN



0,σ



and remain unchanged over the

durations of data transmissions. In addition, each node employs the same transmitted power P

and the

additive noise at relays and destination is modeled as a zero-mean, complex Gaussian random variable

with the variance N

. Since the intermediate wall exists between the source and destination, direct S −D

link is blocked. Fortunately, the relays can assist the source in transmitting data to destination. Under

these assumptions, the average system SNR is P

and the instantaneous SNRs of S −R

and R

−D

link can be expressed as P

and P

respectively, where r

= |h

and r

= |h

are the channel gains.

Among N relays, the “best” relay is selected based on a certain criterion to forward the signal trans-

mitted by the source with AF protocol. The selection is performed by the destination, which collects all

information and feeds the selection decision back to the relays.

Because of the outdated CSI, we denote outdated channel coeﬃcients of the S − R

and R

− D link

which are the ones at relay selection by



and



respectively, which is an outdated version of h

and h

at the time of data transmission. h

and



are jointly Gaussian distribution. Conditioned on



, h

obeys a complex Gaussian distribution [7]: h



∼CN(ρ



, (1 −ρ

)σ

). Likewise,

conditioned on



follows a Gaussian distribution: h



∼CN(ρ



, (1 − ρ

)σ

). The

correlation coeﬃcient between h

and



denoted by ρ

is determined by the model of fading process

[14, Table 2.1], so is ρ

. Here, the correlation coeﬃcients are assumed to be constant. It is worth noting

that although the CSI in relay selection is outdated, the CSI of the destination node is assumed to be

perfect thanks to the pilots in the packet for receiver channel estimation. In CSI-assisted AF mode of

operation, the equivalent instantaneous end-to-end SNR of the link from the source to the destination

via the kth relay is Υ

, which can be calculated by [13]















, for k =1,...,N. (1)

3 Opportunistic relay selection with outdated and statistical CSI

In the absence of outdated CSIs, best relay selection is decided by max

{Υ

}. The performance analysis

of this relay selection strategy is diﬃcult, even if the exact analysis formula can be obtained, which may

be too complicated to work out. Fortunately Υ

has a tight upper bound [12]

= min (P

)  Υ

. (2)

It is worth pointing out that, (2) is a good approximation for (1) and coincides with (1) approximately

at medium and high SNR values. When the average system SNR (P

) is given, the upper bound of

the equivalent end-to-end channel gain is r

= min(r

). Therefore, for analytical simplicity, given

system SNR = P

,weuseγ

instead of γ

in the following analysis. A similar approximation was

also made in many literatures, such as [13].

In this paper, the outdated versions of instantaneous SNR in the S −R

and R

−D links are denoted

by P

r

and P

r

where r

= |



and r

= |



. When the outdated CSI problem

is encountered, no accurate CSIs can be utilized, some papers [7,9,11–13], choose the best relay with

outdated CSIs, i.e., max

(r

)wherer

= min(r

, r

). In the following, we refer to the strategy for

choosing the relay only with outdated CSI as maximum outdated channel gain (MCG) strategy. Although

剩余13页未读，继续阅读

weixin_38612139

粉丝: 3
资源: 885

解决移动场景下过时信道信息对OR-SAR的影响：一种简单放大转发策略

具有过时的信道状态信息的放大转发中继选择的性能分析

基于统计信道状态信息的节能分布式中继选择.pdf

时变瑞利衰落信道中的差分放大转发中继:时变瑞利衰落信道中的差分放大转发-matlab开发

用户选择与过时信道状态信息下的两向中继网络 outage 分析与功率分配优化

基于部分信道状态信息的双向中继系统性能分析 (2011年)

基于深度学习的两跳放大转发中继网络多中继选择策略.pdf

放大转发MIMO中继系统中的快速天线选择算法_放大转发_天线选择算法_中继系统_天线选择_MIMO中继_

两用户放大转发中继系统的机会角色选择

用于两跳MIMO多中继网络的近乎最佳的放大转发中继方案

异步放大转发中继网络的频域差分调制方案

最新资源