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arXiv 1404.3265cs.NI
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认知无线电网络中不同环境下的最优重传策略

Optimal Rendezvous Strategies for Different Environments in Cognitive Radio Networks

Haisheng Tan, Jiajun Yu, Hongyu Liang, Tiancheng Lou, Francis C. M. Lau

摘要:

在认知无线电网络(CRN)中,允许次级用户(SU)机会性地接入授权信道。对于SU来说,一个基本的和必不可少的操作是通过在同一时隙选择一个公共信道来建立通信,这被称为会合问题。在本文中,我们研究的策略,以实现快速会合两个次要用户。次级节点的信道可用性受到时间和空间变化的影响。此外,在分布式系统中,一个用户不知道另一个用户的信道状态。因此,一个快速的会合并不是微不足道的。最近,一些会合策略已被提出用于不同的系统设置,但很少有他们考虑到时间变化的通道。在这项工作中,我们首先推导出一个时间自适应策略与最佳预期的时间交会(TTR)的同步系统在稳定的环境中,信道可用性被假定为是静态的随着时间的推移。接下来,在动态环境中,这更好地代表时间动态信道可用性CRN,我们首先推导出两种特殊情况下的最优策略,然后证明我们的策略仍然是渐近最优的一般动态情况下。通过大量的仿真实验验证了该策略的有效性,并验证了理论分析的正确性.不同的参数对TTR的影响也进行了研究,如通道的数量,通道开放的可能性,环境的动态程度,以及入侵者的存在。

英文摘要:

In Cognitive Radio Networks (CRNs), the secondary users (SUs) are allowed to access the licensed channels opportunistically. A fundamental and essential operation for SUs is to establish communication through choosing a common channel at the same time slot, which is referred to as rendezvous problem. In this paper, we study strategies to achieve fast rendezvous for two secondary users. The channel availability for secondary nodes is subject to temporal and spatial variation. Moreover, in a distributed system, one user is oblivious of the other user's channel status. Therefore, a fast rendezvous is not trivial. Recently, a number of rendezvous strategies have been proposed for different system settings, but rarely have they taken the temporal variation of the channels into account. In this work, we first derive a time-adaptive strategy with optimal expected time-to-rendezvous (TTR) for synchronous systems in stable environments, where channel availability is assumed to be static over time. Next, in dynamic environments, which better represent temporally dynamic channel availability in CRNs, we first derive optimal strategies for two special cases, and then prove that our strategy is still asymptotically optimal in general dynamic cases. Numerous simulations are conducted to demonstrate the performance of our strategies, and validate the theoretical analysis. The impacts of different parameters on the TTR are also investigated, such as the number of channels, the channel open possibilities, the extent of the environment being dynamic, and the existence of an intruder.

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。

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