Performance comparison of hard and soft fusion Techniques for Energy Efficient CSS in Cognitive Radio

In this paper Comparative analysis of hard and soft fusion techniques for Energy Efficient cooperative spectrum sensing (CSS) is presented. CSS is the efficient way of detecting spectrum holes in cognitive radio (CR) network by combining sensing information of various CR users also known as secondary users (SUs). In CSS, energy resources become precious when the SUs in CR network are battery operated. So it becomes important to use their energy efficiently. In this paper, Hard fusion techniques like AND, OR and Majority and soft fusion techniques like square law selection (SLS) and square law combine (SLC) fusion are explained and fusion rule threshold that maximizes the EE is calculated. Results show that for Energy Efficient CSS, Majority fusion outperforms other fusion techniques. For majority fusion EE is 4.4% more compared to SLS fusion and maximum EE is 3.8 Mbits/Hz/joule at sensing time equals to 2ms.