Spectrum Sensing using Distributed Sequential Detection via Noisy Reporting MAC

TL;DR

This paper introduces a decentralized sequential detection algorithm for cooperative spectrum sensing in Cognitive Radios, accounting for noisy reporting channels and uncertainties, to improve detection speed and energy efficiency.

Contribution

It proposes a novel distributed sequential detection scheme, DualSPRT, with theoretical analysis, and enhancements for noise robustness and SNR uncertainties in cognitive radio spectrum sensing.

Findings

The proposed algorithms achieve low detection delay with controlled error probabilities.

Theoretical analysis confirms the asymptotic optimality of the algorithms.

Modifications improve robustness to noise, fading, and SNR uncertainties.

Abstract

This paper considers cooperative spectrum sensing algorithms for Cognitive Radios which focus on reducing the number of samples to make a reliable detection. We develop an energy efficient detector with low detection delay using decentralized sequential hypothesis testing. Our algorithm at the Cognitive Radios employs an asynchronous transmission scheme which takes into account the noise at the fusion center. We start with a distributed algorithm, DualSPRT, in which Cognitive Radios sequentially collect the observations, make local decisions using SPRT (Sequential Probability Ratio Test) and send them to the fusion center. The fusion center sequentially processes these received local decisions corrupted by noise, using an SPRT-like procedure to arrive at a final decision. We theoretically analyse its probability of error and average detection delay. We also asymptotically study its performance. Even though DualSPRT performs asymptotically well, a modification at the fusion node provides more control over the design of the algorithm parameters which then performs better at the usual operating probabilities of error in Cognitive Radio systems. We also analyse the modified algorithm theoretically. Later we modify these algorithms to handle uncertainties in SNR and fading.