Performance of the Gerschgorin Radii and Centers Ratio Detector for Cooperative Spectrum Sensing under Burst Control Channel Errors

Lucas Costa,Dayan Guimarães,Rausley Souza

doi:10.14209/jcis.2019.15

Abstract

In centralized cooperative spectrum sensing (CSS), cognitive radios (CRs) monitor the spectrum and send the related data to a fusion center (FC) via a control channel in order to more efficiently detect possible idle bands for opportunistic occupation. In centralized cooperative spectrum sensing (CSS), cognitive radios (CRs) monitor the spectrum and send the related data to a fusion center (FC) via a control channel in order to more efficiently detect possible idle bands for opportunistic occupation. In practice, such data must be quantized prior to transmission, which can lead to loss of the global spectrum sensing performance due to quantization errors. Additionally, wireless control channel impairments, such as the multipath fading, further contributes to performance degradation. In many researches, the control channel is considered error-free. Even when errors are considered, they usually affect the transmitted symbols independently, that is, the control channel is assumed to be memoryless. Error bursts come from the memory effect of the channel, and are typically found in wireless communications. In this paper we consider the effects of burst errors in the control channel as well as the problem of signal distortion caused by three methods of quantization in centralized CSS with sample fusion. The Gerschgorin Radii and Centers Ratio (GRCR) detector is used as the test statistic for spectrum sensing. Our findings show that: i) the GRCR is robust in the scenarios taken into consideration, ii) the uniform quantization may be preferred in some cases when the control channel is considered perfect, iii) the nonuniform quantization attains better performance under errors in the control channel, and iv) the effect of memory in the control channel may produce, in some situations, performance gains with respect to the memoryless channel, when both have the same average bit error rate.

Highlights

T HE rapid expansion of telecommunications services is the primary reason for the current problem of spectrum scarcity and congestion
Our results show that: i) the Gerschgorin radii and centers ratio (GRCR) detector is robust in the scenarios analyzed, ii) the uniform quantization may be preferred in some cases when the control channel is assumed to be perfect, iii) the nonuniform quantization attains better performance under errors in the control channel, and iv) the effect of memory in the control channel can generate performance gains with respect to the memoryless channel when both are subjected to the same average bit error probability
Signal statistics at its input, such as the probability density function (PDF) and the cumulative distribution function (CDF), are in this case completely ignored in the quantization process, and the signal is treated as if it was evenly distributed across its dynamic range

Summary

Introduction

T HE rapid expansion of telecommunications services is the primary reason for the current problem of spectrum scarcity and congestion. Research shows that several spectrum bands are underutilized, since the holders of the exclusive right of use do not do so uninterruptedly and in. This article is an invited extended version of [1], Best Paper Award SBrT 2018, which was presented in the XXXVI Simpósio Brasileiro de Telecomunicações e Processamento de Sinais (SBrT 2018), Campina Grande, PB, Brazil, September 16-19, 2018. There are idle bands that could be more efficiently used [2]

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