Abstract
Cooperative energy detection (CED) is a key technique to identify the spectrum holes in cognitive radio networks. Previous study on this technique mainly aims at improving the detection accuracy, while paying little attention to the performance of detection time. This paper concentrates on the issue of fast CED, which is achieved by minimizing its detection time subject to the constraints on detection accuracy. Firstly, the prevalent counting rule based CED algorithm is optimized. Taking the special cases of counting rule (AND rule and OR rule), for example, we show that detection time can be minimized by selecting an optimal number of secondary users. Moreover, we prove that OR rule is superior to AND rule in detection time, and thus OR rule based CED is faster than AND rule based CED. Then, a sequential test (ST) based CED algorithm is proposed to exploit the benefit of ST and detect primary user even faster. After analyzing its detection time, we illustrate that ST based CED is able to spend the minimal detection time in satisfying the accuracy constraints by choosing an optimal sample number. Simulation results are provided to verify the effectiveness of both fast algorithms discussed in this paper.
Highlights
The significant achievement in wireless technologies has inspired masses of wireless services, which facilitate human life and bring about considerable requirements on spectrum resource, causing the so-called “spectrum scarcity” problem
Cognitive radio (CR) is one of the promising techniques to alleviate this problem by allowing secondary users (SUs) to recycle the “spectrum holes” on the spectrum band that has been licensed to primary user (PU) for exclusive use
This paper jointly considers these two performance metrics based on some well-proved tools in cooperative energy detection (CED) and achieves fast CED via minimizing the detection time subject to the detection accuracy constraints
Summary
The significant achievement in wireless technologies has inspired masses of wireless services, which facilitate human life and bring about considerable requirements on spectrum resource, causing the so-called “spectrum scarcity” problem. The sensing results can be either raw information SUs have observed [6,7,8] or local decisions SUs have made based on the observations [9, 10], leading to CED with soft and hard combination [11], respectively. This paper jointly considers these two performance metrics based on some well-proved tools in CED and achieves fast CED via minimizing the detection time subject to the detection accuracy constraints.
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