Active spectrum sensing for cognitive radio networks

Abstract

An energy detection-based active spectrum sensing scheme is proposed to carry out spectrum sensing and secondary transmissions simultaneously. It successfully avoids the widely used quiet periods, which have at least two shortcomings. First, periodical interruptions of secondary transmissions degrade the quality of service of secondary networks (e.g. decreasing the system capacity and increasing end-to-end packet delay). Second, frequent tight synchronisation is necessary but very difficult to implement in the distributed networks. With the assistance of the geolocations, the proposed sensing scheme is able to decompose the received power into the primary signal power, secondary signal power, and the device noise power. The power decomposition is formulated into a problem of solving a homogeneous linear equation set with a coefficient matrix involving only the distances among the primary users, secondary users, and the sensors. Through the decomposition, the primary signal power can be differentiated from the secondary signal power, which is generally treated as interference in spectrum sensing. When constructing the test statistic, such interference can be cancelled from the collected energy. As a result, the noise uncertainty problem, which significantly compromises the performance of the energy detection, can be greatly alleviated by noticing the fact that the interference dominates the noise uncertainty problem. Because the achieved signal-to-interference ratio can be improved by cancelling the interference, the detection errors in terms of the probability of false alarm and missed detection can be significantly reduced. Simulations verify the feasibility and efficiency of the proposed scheme.

Bayesian inference and fuzzy inference for spectrum sensing order in cognitive radio networks

“…Evaluations showed a fairly good performance of the proposed technique with low degradation in terms of throughput. Similarly, reducing the frequency of sensing operations was the main goal of Zhao and Sasaki as well. However, they were trying to eliminate the need for quiet period when energy detection is used.…”

Kernel canonical correlation analysis for robust cooperative spectrum sensing in cognitive radio networks

“…This scenario is considered in , where an interference‐mitigation scheme close to macrocell/femtocell real‐life scenario is experimentally evaluated. Another recent work that takes into account interference in the CR context is , where, with the assistance of geolocation information, a sensing scheme that decomposes the received power into the primary signal power, secondary signal power (treated here as interference) and the device noise power is proposed. In this way, after decomposing the total power, the interference power can be canceled prior to PU detection.…”

Performance evaluation of energy based spectrum sensing in multipath fading channel for cognitive radio system

“…Kalamkar et al [6] have studied the detection performance of energy detector under different distribution of noise uncertainty and their effects on generalized energy detector. An active spectrum sensing scheme based on energy detector was proposed by B.Zhao et al [7]. It was concluded that the performance of the suggested sensing scheme was degraded in Rayleigh fading condition but their performance can be enriched by spending prolonged observation time which is comparable to AWGN channel.…”