• 中国计算机学会会刊
  • 中国科技核心期刊
  • 中文核心期刊

计算机工程与科学

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非同分布衰落环境下最大链路选择方案及性能研究

贾向东1,2,颉满刚1,周猛1   

  1. (1.西北师范大学计算机科学与工程学院,甘肃 兰州 730070;
    2.南京邮电大学江苏省无线通信重点实验室,江苏 南京 210003)
     
  • 收稿日期:2015-11-23 修回日期:2016-05-21 出版日期:2017-11-25 发布日期:2017-11-25
  • 基金资助:

    国家自然科学基金(61261015,61561043);甘肃省杰出青年基金(1308RJDA007)

A max link selection scheme over independent
and non-identically distributed fading channel

JIA Xiang-dong1,2,XIE Man-gang1,ZHOU Meng1   

  1. (1.College of Computer Science and Engineering,Northwest Normal University,Lanzhou 730070;
    2.Wireless Communication Key Lab of Jiangsu Province,
    Nanjing University of Posts and Telecommunications,Nanjing 210003,China)
  • Received:2015-11-23 Revised:2016-05-21 Online:2017-11-25 Published:2017-11-25

摘要:

通过对Nakagami-m衰落环境下缓冲中继协作最大链路选择方案(MLS)的中断和延迟性能的研究,得到了中断概率和平均分组延迟的闭式解析解以及相应的分集增益和编码增益。基于所得结果,给出了中断概率和平均分组延迟的数值分析,结果表明,非同分布衰落环境不仅严重地影响了MLS方案的分集增益和编码增益,而且使得各个中继节点处的平均分组延迟也不相同,系统极不稳定。为此提出了一种新颖的基于加权的MLS(W-MLS)方案,该方案一方面使信源-中继和中继-信宿链路等效功率分别相同;另一方面使中继-信宿链路等效功率略大于信源-中继链路等效功率,这样,不仅可以保证系统获得足够的分集增益,而且可以显著地降低平均分组延迟,使得各个中继节点处的平均分组延迟完全相同,提高了系统的稳定性。
 
 

关键词: 中继协作, 缓冲区, 最大链路选择, 中断性能, 延迟, Nakagami-m

Abstract:

We focus on the buffer-aided max link selection (MLS) relaying system in term of outage and delay performance over independent and non-identically distributed Nakagami-m fading channels. By using appropriate mathematical manipulation, the exact closed-form expressions of outage probability and average packet delay are achieved firstly, as well as the diversity and coding gains. The presented numerical results show that the non-identically distributed fading channels impose great loss in diversity gain for the MLS schemes. Moreover, the buffer-aided relaying systems are also unstable due to the fact that the average packet delays at all relays are different under this condition. Therefore, to improve the diversity and delay performance, we propose a novel weighted-based MLS (W-MLS) scheme. By employing weight vectors, the W-MLS scheme on one hand makes the equivalent powers of source-relay and relay-destination links equal. On the other hand, the W-MLS scheme also ensures that the equivalent power of relay-destination links is  greater than the one of source-relay links. As a result, comparing with the traditional MLS, the proposed W-MLS scheme can not only provide enough diversity and coding gains, but also enhance the stability of buffer-aided relaying systems due to that the average packet delays at all relays are entirely the same.
 

Key words: relay cooperation, buffers, max link selection, outage performance, delay, Nakagami-m