arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0905.2413cs.ITmath.IT
收藏

衰落信道的中断容量与最优传输

Outage Capacity and Optimal Transmission for Dying Channels

Meng Zeng, Rui Zhang, Shuguang Cui

摘要:

在无线网络中,通信链路可能会受到随机的致命影响:例如,传感器网络突然断电或认知无线电网络与不可预测的主用户频谱占用。在这种情况下,关键是要量化如何快速和可靠地通过受攻击的链接收集信息。对于一个单一的点对点信道受到随机攻击,命名为一个\emph{dying channel},我们建模为块衰落(BF)信道有限和随机延迟约束。首先,我们定义的中断容量的性能指标,其次研究的最佳编码长度$K$,使中断概率最小化时,均匀的功率分配假设。对于一个给定的速率目标和编码长度$K$,我们然后最小化中断概率的功率分配向量$\mv{P}_{K}$,并表明,这个优化问题可以转化为凸优化问题在一定条件下。讨论了几种特殊情况下的最优解。此外,我们扩展了单点到点垂死信道的结果,并行多信道的情况下,每个子信道是一个垂死的信道,并调查了相应的渐近行为的整体中断概率与两种不同的攻击模型:独立的攻击情况下和$m$依赖的攻击情况。可以看出,如果\emph{rate per unit cost}小于某个阈值,则随着子信道数量的增加,两种情况下的总中断概率都减小到零。中断指数也研究了如何快速的中断概率提高的子信道的数量。

英文摘要:

In wireless networks, communication links may be subject to random fatal impacts: for example, sensor networks under sudden power losses or cognitive radio networks with unpredictable primary user spectrum occupancy. Under such circumstances, it is critical to quantify how fast and reliably the information can be collected over attacked links. For a single point-to-point channel subject to a random attack, named as a \emph{dying channel}, we model it as a block-fading (BF) channel with a finite and random delay constraint. First, we define the outage capacity as the performance measure, followed by studying the optimal coding length $K$ such that the outage probability is minimized when uniform power allocation is assumed. For a given rate target and a coding length $K$, we then minimize the outage probability over the power allocation vector $\mv{P}_{K}$, and show that this optimization problem can be cast into a convex optimization problem under some conditions. The optimal solutions for several special cases are discussed. Furthermore, we extend the single point-to-point dying channel result to the parallel multi-channel case where each sub-channel is a dying channel, and investigate the corresponding asymptotic behavior of the overall outage probability with two different attack models: the independent-attack case and the $m$-dependent-attack case. It can be shown that the overall outage probability diminishes to zero for both cases as the number of sub-channels increases if the \emph{rate per unit cost} is less than a certain threshold. The outage exponents are also studied to reveal how fast the outage probability improves over the number of sub-channels.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑