Optimised fusion rule in cluster-based energy-efficient CSS for cognitive radio networks

ABSTRACT

Cooperative spectrum sensing (CSS) can solve the problem of the hidden terminal in cognitive radio (CR). Energy consumption and sensing time are high in CSS due to a large number of users. In CSS, the parameters that affect the energy efficiency (EE) of the system are fusion rule, sensing time, transmission power and number of users. In this paper, four fusion rules OR-OR, AND-OR, OR-AND and AND-AND are proposed for cluster-based CSS and optimum fusion rule is determined. It is found that in terms of EE metric, AND-OR rule outperforms the other fusion rules. An iterative algorithm has been proposed which finds the optimum number of CR users in a cluster and total number of clusters that maximises the EE. Quantitatively at SNR = −20 dB, EE is maximum when number of clusters equals to 4 and number of users in the cluster equals to 3 for 12 fixed number of users. The maximum EE is 3.69 Mbits/Hz/joule at sensing time 1.5 ms.

KEYWORDS:

• Cooperative spectrum sensing (CSS)
• wireless sensor network (WSN)
• cognitive radio (CR)
• energy efficiency (EE)
• cluster head (CH)

Disclosure statement

No potential conflict of interest was reported by the authors.