Cooperative relay to improve diversity in cognitive radio networks
Cooperative relay to improve diversity in cognitive radio networks
复制标题
DOI：
10.1109/mcom.2009.4785388
复制
发表时间：
2009-02
期刊：
影响因子：
--
通讯作者：
Qian Zhang;Juncheng Jia;Jin Zhang
中科院分区：
文献类型：
--
作者：
Qian Zhang;Juncheng Jia;Jin Zhang
最近的研究表明，动态频谱接入通过允许二次非授权用户动态共享主授权用户未使用的频谱，可以显著提高频谱利用率。认知无线电被提出通过机会性地利用频谱“空洞”的存在来提高频谱利用率。同时，协作中继技术被广泛认为是提高包括认知无线电网络在内的各种类型无线网络中传输分集增益的关键技术。在本文中，我们首先对协作中继技术在CRN中的应用进行了简要的概述，包括由次级用户协同传输主业务、次级节点之间协同传输以提高空间分集、次级节点之间协同中继以提高频谱分集。由于后者是一个新的方向，在本文中，我们将重点关注这一场景，并研究一个简单的无线网络，其中选择一个频谱丰富的节点作为中继节点，以提高源和目的地之间的性能。随着协作中继的引入，需要考虑许多独特的问题，尤其是中继选择和频谱分配问题。为了验证认知无线电协作中继的可行性和性能，提出了一种新的MAC协议，并在基于软件无线电外设的通用测试床上实现了该协议。实验结果表明，利用协作中继的优势，大大提高了整个系统的吞吐量。
Recent studies demonstrated that dynamic spectrum access can improve spectrum utilization significantly by allowing secondary unlicensed users to dynamically share the spectrum that is not used by the primary licensed users. Cognitive radio was proposed to promote the spectrum utilization by opportunistically exploiting the existence of spectrum "holes." Meanwhile, cooperative relay technology is regarded widely as a key technology for increasing transmission diversity gain in various types of wireless networks, including cognitive radio networks. In this article, we first give a brief overview of the envisioned applications of: cooperative relay technology to CRNs, cooperative transmission of primary traffic by secondary users, cooperative transmission between secondary nodes to improve spatial diversity, and cooperative relay between secondary nodes to improve spectrum diversity. As the latter is a new direction, in this article we focus on this scenario and investigate a simple wireless network, where a spectrum-rich node is selected as the relay node to improve the performance between the source and the destination. With the introduction of cooperative relay, many unique problems should be considered, especially the issue for relay selection and spectrum allocation. To demonstrate the feasibility and performance of cooperative relay for cognitive radio, a new MAC protocol was proposed and implemented in a universal software radio peripheral-based testbed. Experimental results show that the throughput of the whole system is greatly increased by exploiting the benefit of cooperative relay.