Efficient Spectrum Sensing for Cognitive Radio Networks via Joint Optimization of Sensing Threshold and Duration

Abstract

Abstract-Cognitive radio networks require fast and reliable spectrum sensing to achieve high network utilization by secondary users. Optimization approaches to spectrum sensing todate have largely focused on maximizing throughput for secondary users while considering only a single parameter variable pertinent to sensing -notably the threshold or duration, but not both. In this work, we investigate the impact of true joint minimization under two performance criteria: a) minimization of the average time to detection of a spectrum hole and b) joint maximization of the aggregate opportunistic throughput. We show that the resulting non-convex problem is actually biconvex under practical conditions for which effective algorithms can be developed that yields reliable numerical procedures to solve the resulting optimization problem. The results show that the proposed approach can considerably improve system performance (in terms of the mean time to detect a spectrum hole and also the aggregate opportunistic throughput of both primary and secondary users), relative to the scenarios with only a single sensing variable or a sub-optimal ad-hoc optimization approach used for two variable case.

Performance evaluation of improved double-threshold energy detector over Rayleigh-faded sensing and imperfect reporting channels

“…8 λ = 1 is a special case in which the parameter ξ equals 1 for all values of p. In this case, we cannot find the optimized value of P err . From this figure and (29), it is also proved that if we choose a very large value of p (p → ∞), then we will face the same situation as λ = 1 in which ξ ≈ 1 and there is no performance improvement.…”

“…In other words, it is possible to find an optimum ξ given other parameters to minimize P err . From (29), there exists a direct relationship between p and λ for a particular ξ . Thus, there are many different pairs of (p, λ) for an optimum ξ to satisfy this equation, in which one of them is p = 2 (which implies CED).…”

“…Nonetheless, they just analyzed the CSS scheme over perfect reporting channels which is also analyzed for AWGN and Rayleigh-faded sensing channel in [27,28], respectively. The joint optimization of the threshold and the number of sensing samples was formulated in [29] to improve system performance in terms of the mean detection time and also the aggregate throughput of both PU and SU over a non-CSS scheme. In [30], the throughput of CSS networks over imperfect reporting channels has been evaluated.…”

On the effect of false alarm rate on the performance of cognitive radio networks

“…As a result, there has been considerable research effort focusing on CR techniques that enable using radio spectrum efficiently. In CR networks (CRNs), unlicensed secondary users (SUs) employ spectrum sensing [4][5][6] to discover spectrum holes during the absence of licensed primary users (PUs) before attempting network access. Energy detection [7][8][9] is the simplest method for detecting the presence of PUs.…”

Sensing or Transmission: Causal Cognitive Radio Strategies with Censorship

“…In another interesting publication [35], the probability of detection of the PU was considered as the constraint, under which the secondary rate was optimized. The same authors presented efficient spectrum sensing for CR networks via joint optimization of sensing threshold and duration in [36].…”