Transport capacity of cooperative cognitive radio ad hoc networks
Transport capacity of cooperative cognitive radio ad hoc networks
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DOI：
10.1016/j.phycom.2017.01.001
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发表时间：
2017-12
期刊：
影响因子：
--
通讯作者：
Jing Gao;Yinghui Zhang;Yang Liu
中科院分区：
文献类型：
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作者：
Jing Gao;Yinghui Zhang;Yang Liu
第五代移动通信网络（5G）的频谱特性越来越复杂，传统的性能指标的改进也越来越具有挑战性。如何在不占用更多频谱的情况下提高网络容量已成为5G的重要研究内容之一。研究了协作认知无线电自组网的传输容量问题。为了表征传输容量，引入了半时隙ALOHA多址接入协议。在每个时隙中，根据次用户与主发射机之间的位置关系，将次用户分为协作次用户和普通用户。主发射机在前半时隙发送它们的分组，而在后半时隙保持静默。普通次级用户在整个时隙中以概率p发送其分组。协作次用户在第一半时隙中从其对应的主发射机接收分组，并且在第二半时隙中将分组转发到主接收机。基于该协议，推导出了一次传输容量和平均二次传输容量的界的封闭表达式。在此基础上，分析了主覆盖半径和次覆盖半径这两个重要参数的性能优化问题。理论结果表明，可以找到一个最佳的主覆盖半径，以最大限度地提高主网络的传输能力。而二次网络的传输容量随着二次覆盖半径的增大而增大。分析表明，二次协作可以提高网络的传输成功率，从而提高网络的传输能力。
It is more challenging for improving the traditional performance metrics for the 5-th generation network (5G) because of more congestible frequency spectrum. How to improve the network capacity without using more spectrum has become one of important studies in 5G. In this paper, the transport capacity of cooperative cognitive radio ad hoc networks is studied. In order to characterize the transport capacity, a half-slotted ALOHA multiple access protocol is introduced. In each slot, secondary users are divided into cooperative secondary users and ordinary users dependent on the positional relationship between them and primary transmitters. Primary transmitters send their packets in the first half slot while keep silence in the second half slot. Ordinary secondary users send their packets at a probability p in the whole slot. Cooperative secondary users receive the packets from their corresponding primary transmitters in the first half slot and forward them to the primary receivers in the second half slot. The closed-form expressions of the bounds of primary transport capacity and mean secondary transport capacity are derived based on the protocol. Furtherly, the optimal problem of the performance is analyzed about two important parameters: primary and secondary coverage radius. Theoretical results show that an optimal primary coverage radius could be found to maximize the transport capacity of primary network. While the transport capacity of secondary network increases with the increasing secondary coverage radius. The analysis reveals that the transport capacity could be improved by secondary cooperation because of higher successful transmission probability.