Abstract
For a CR system operating under the energy detection scheme of spectrum sensing, it is much important to have low values of probability of false alarm \(P_{fa}\) and probability of missed detection \(P_{md}\). However, due to inherent tradeoff between \(P_{fa}\) and \(P_{md}\), it is challenging to simultaneously achieve high value of throughput while maintaining a sufficient level of protection to the licensed users. To overcome this challenge, this paper proposes a CR system which while operating under the double threshold scheme does not only promise a high value of throughput but it also ensures a target level of protection to the licensed users. We further study the problem of designing a sensing duration to maximize the achievable throughput for the secondary network under the constraint that the primary users are sufficiently protected. We formulate the sensing-throughput tradeoff problem mathematically, and prove that the formulated problem indeed has one optimal sensing time which yields the highest throughput for the secondary network. To overcome uncertainties of the wireless communication channel, the proposed approach was further been implemented under the cooperation of \(n - out - of - k\) CRs. It is observed that, under the proposed approach, the CR user while ensuring a target level of protection to the licensed users achieves a significant gain in throughput than the CR systems based on the single and double thresholds both.









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Notes
The partial underlay scheme is different from the basic underlay scheme [10, 11] of spectrum access as it does not always transmit using low power. But, unlike to underlay scheme where no sensing is needed, under the proposed system, the sensing is performed in alternate slots using the frame structure of Fig. 1. It is also different from the sensing based spectrum sharing (SSS) scheme [12, 13] where communication is performed under the low and high transmission powers based on the sensed status (active/idle) of the channel. But, in the proposed system, the low power transmissions are done for the confused region only, while, for the busy status of the channel, the channel search operation is initiated.
Transmit with a power which is needed to ensure a sufficient data rate. The transmissions are performed as if SU itself was a licensed user.
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Verma, G., Sahu, O.P. Throughput Maximization of Cognitive Radio Under the Optimization of Sensing Duration. Wireless Pers Commun 97, 1251–1266 (2017). https://doi.org/10.1007/s11277-017-4564-x
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DOI: https://doi.org/10.1007/s11277-017-4564-x