Abstract
Cognitive radio is one of the most promising technologies due to the spectrum scarcity, especially in the microwave band. Spectrum sensing forms an essential functionality for CR systems. However, such detection performance is usually compromised by shadowing and fading channel conditions. Cooperative sensing is one of the crucial solutions to overcome degraded detection performance. A distributed architecture for the processing and fusion of sensing information is proposed to improve sensing performance and reduce reporting error. The decision fusion for cooperated users could be complex in dense network scenarios and reported sensing traffic may require significant bandwidth. The paper presents a new cooperative distributed PUs detection and proposes dynamic threshold based on controlled probability of false alarm to enhance sensing efficiency and reliability in a Rayleigh fading environments. A cooperative distributed PUs detection is realized by fusion node (FNs) that dynamically selected from the group members. The adaptive detection threshold is computed dynamically using the link quality indicators (LQIs) of the sensing channels. Moreover, the proposed scheme can significantly minimize the typically transmitted bits in the reporting channels. This work also deliberated the design parameters of the CR on the performance of fusion values. The simulation evaluation presents that the adapted threshold considerably improves the performance of the distributed cooperative sensing (DCS) process. The simulation results verified that the error was minimized remarkably. The ROC graph is notably enhanced for the sensing process in term of probability of detection and probability of false alarm. Finally, it was presented that with the proposed scheme the sensitivity requirements could be significantly enhanced up to 0.95.
Highlights
Radio spectrum becomes one of the international wealth that get the attention of researchers and academia since early this century
A distributed detection is developed by selecting fusion nodes (FN) that are dynamically selected from a group of nodes
The simulation analysis shows that the performance of the distributed cooperative sensing (DCS) process is considerably improved by the adapted threshold
Summary
Radio spectrum becomes one of the international wealth that get the attention of researchers and academia since early this century. Shown that when the number of cognitive users increases the probability of bit error is increased, which dramatically reduces the spectrum agility Due to all these problematic issues, cooperative spectrum sensing in cognitive radio has been proposed recently to support the decision of the local sensing /detection and improve the probabilities of false alarm and detection [14,15,16,17]. Where an auto-correction scheme is introduced for the reported bit error, and reduces and minimizes the number of bits in the reporting channels by letting the user with detected information only to send its report Even though this method reduced the required bandwidth and energy in the reporting channel, due to only a few SUs are reporting their observations without hearing from the other users, the spectrum agility can be degraded dramatically with the number of users in the network.
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