ABSTRACT

In cooperative spectrum sensing (CSS), in order to maximise the energy efficiency (EE) of cognitive radio (CR) users, users are divided into clusters. In this paper, the optimal inter-fusion rule threshold formula for different number of clusters and users is proposed for maximum EE in cluster-based CSS (CB-CSS). Different fusion rules are investigated for this purpose over Nakagami and Rician fading channel conditions. Simulations are conducted for different number of clusters and users using AND and OR intra-fusion rules and inter-fusion rule threshold is optimised in CB-CSS over the Nakagami-m fading channel and the Rician fading channel. The obtained mathematical expression for the inter-fusion rule threshold is verified by the results. It is investigated that when number of clusters are $P=4$ and number of users in a cluster are $K=6$, OR-AND ($n=1$, $r=P$) fusion rule achieves 2.46% more EE than AND-OR ($n=K$, $r=1$) fusion rule in case of Nakagami fading channel and 5.06% more EE than AND-OR fusion rule in case of Rician fading channel. Further, EE with respect to number of users is compared between additive white gaussian noise (AWGN) channel and Nakagami and Rician fading channels.

摘要

在协作频谱感知（CSS）中，为了最大化认知无线电（CR）用户的能量效率（EE），用户被划分为集群。本文针对基于集群的 CSS (CB-CSS) 中的最大 EE，提出了针对不同集群数和用户数的最优互融合规则阈值公式。为此目的，在 Nakagami 和 Rician 衰落信道条件下研究了不同的融合规则。使用 AND 和 OR 内部融合规则对不同数量的集群和用户进行模拟，并在 CB-CSS 中在 Nakagami-m 衰落信道和 Rician 衰落信道上优化相互融合规则阈值。得到的融合规则阈值的数学表达式由结果验证。研究发现，当簇数为$磷=4$和集群中的用户数是$ķ=6$, OR-AND ($n=1$,$r=磷$) 融合规则比 AND-OR ($n=ķ$,$r=1$) Nakagami 衰落信道情况下的融合规则，在 Rician 衰落信道情况下，EE 比 AND-OR 融合规则高 5.06%。此外，在加性高斯白噪声 (AWGN) 信道与 Nakagami 和 Rician 衰落信道之间比较了关于用户数量的 EE。