Abstract

This paper presents two new algorithms for wideband spectrum sensing at sub-Nyquist sampling rates, for both single nodes and cooperative multiple nodes. In single-node spectrum sensing, a two-phase spectrum sensing algorithm based on compressive sensing is proposed to reduce the computational complexity and improve the robustness at secondary users (SUs). In the cooperative multiple nodes case, the signals received at SUs exhibit a sparsity property that yields a low-rank matrix of compressed measurements at the fusion center. This therefore leads to a two-phase cooperative spectrum sensing algorithm for cooperative multiple SUs based on low-rank matrix completion. In addition, the two proposed spectrum sensing algorithms are evaluated on the TV white space (TVWS), in which pioneering work aimed at enabling dynamic spectrum access into practice has been promoted by both the Federal Communications Commission and the U.K. Office of Communications. The proposed algorithms are tested on the real-time signals after they have been validated by the simulated signals in TVWS. The numerical results show that our proposed algorithms are more robust to channel noise and have lower computational complexity than the state-of-the-art algorithms.

Highlights

  • W ITH the rapid development of wireless communications, the scarcity of spectrum resources becomes an urgent problem

  • In order to reduce the computational complexity during signal recovery process and enhance algorithm’s robustness to imperfect channel noise, we propose a two-phase spectrum sensing algorithm for single node based on compressive sensing (CS)

  • The performance of proposed two-phase cooperative spectrum sensing (CSS) algorithm is presented by considering the influence of multipath deep fading, different number of measurements observed at the fusion center (FC) and different network sizes are analyzed

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Summary

INTRODUCTION

W ITH the rapid development of wireless communications, the scarcity of spectrum resources becomes an urgent problem. In order to remove the sparsity level estimation step, Sun et al [11] proposed to adjust the number of compressed measurements adaptively by acquiring compressed measurements step by step in continuous sensing slots This iterative process introduces higher computational complexities at the SU as signal reconstruction has to be performed several times until the exact signal recovery is achieved. Zeng et al [19] proposed a distributed CSS algorithm in which sensing samples rather than sensing decisions are exchanged with the neighbour SUs within multi-hops to reach a global fusion at the cost of increasing network load. A sub-Nyquist sampling based CSS algorithm with high spectrum resolution, low computational complexity and high robustness to noise is required. A two-phase CSS algorithm based on lowrank matrix completion (MC) is proposed to reduce the signal acquisition costs at SUs and the spectrum resolution and improve the robustness to channel noise. PROPOSED TWO-PHASE SINGLE NODE SPECTRUM SENSING ALGORITHM BASED ON COMPRESSIVE SENSING

System model
Computational complexity and spectrum efficiency analyses
Analyses on simulated signals
Analyses on real-time signals
The denoised cooperative spectrum sensing algorithm
Computational complexity and performance analyses
CONCLUSIONS
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