A Hybrid Combination Scheme for Cooperative Spectrum Sensing in Cognitive Radio Networks

Changhua Yao,Qihui Wu

doi:10.1155/2014/106106

Changhua Yao, Qihui Wu

Open Access

https://doi.org/10.1155/2014/106106

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Abstract

We propose a novel hybrid combination scheme in cooperative spectrum sensing (CSS), which utilizes the diversity of reporting channels to achieve better throughput performance. Secondary users (SUs) with good reporting channel quality transmit quantized local observation statistics to fusion center (FC), while others report their local decisions. FC makes the final decision by carrying out hybrid combination. We derive the closed-form expressions of throughput and detection performance as a function of the number of SUs which report local observation statistics. The simulation and numerical results show that the hybrid combination scheme can achieve better throughput performance than hard combination scheme and soft combination scheme.

Highlights

Cognitive radio (CR) is a promising technology to combat spectrum scarcity by exploiting the unused spectrum bands licensed to the primary user (PU) [1, 2]
We propose a novel hybrid combination scheme in cooperative spectrum sensing (CSS), which utilizes the diversity of reporting channels to achieve better throughput performance
The reporting overhead cannot be ignored when the local sensing data is reported to the fusion center (FC) through a common control channel, which is stringent bandwidth-limited for the efficient usage of limited spectrum resource [9, 10]

Summary

Introduction

Cognitive radio (CR) is a promising technology to combat spectrum scarcity by exploiting the unused spectrum bands licensed to the primary user (PU) [1, 2]. There are many researches about spectrum sensing which plays a key role in cognitive radio systems and collaborative spectrum sensing schemes that have been proposed to improve the reliability of sensing [3,4,5,6,7,8], but it introduces additional information exchange which leads to reporting overhead. Some introduce multibit quantization combining scheme [11], to reduce the amount of transmitted data, and some focus on the selection of the collaborative users [12]. All the related researches adopt either hard combination scheme or soft combination scheme and assume that the data rates on the reporting channels between SU and FC are all the same. The theoretical analysis and simulation show that the hybrid combination scheme outperforms hard combination and soft combination scheme

System Model

Performance Analysis

Numerical Results and Discussions

Conclusions