Abstract
Abstract In this paper, both the security and the reliability performance of the cognitive amplify-and-forward (AF) relay system are analyzed in the presence of the channel estimation error. The security and the reliability performance are represented by the outage probability and the intercept probability, respectively. Instead of perfect channel state information (CSI) predominantly assumed in the literature, a certain channel estimation algorithm and the influence of the corresponding channel estimation error are considered in this study. Specifically, linear minimum mean square error estimation (LMMSE) is utilized by the destination node and the eavesdropper node to obtain the CSI, and the closed form for the outage probability and that for the intercept probability are derived with the channel estimation error. It is shown that the transmission security (reliability) can be improved by loosening the reliability (security) requirement. Moreover, we compare the security and reliability performance of this relay-based cognitive radio system with those of the direct communication system without relay. Interestingly, it is found that the AF relay-based system has less reliability performance than the direct cognitive radio system; however, it can lower the sum of the outage probability and the intercept probability than the direct communication system. It is also found that there exists an optimal training number to minimize the sum of the outage probability and the intercept probability.
Highlights
Nowadays, the increasing demand for high data rate wireless access and services brings about the problem of spectrum scarcity [1]
FCC [4] gives a formal definition of Cognitive radio (CR): ‘A cognitive radio is a radio that can change its transmitter parameters based on interaction with the environment it operates’
We study the security and reliability performance of the cognitive amplify-and-forward (AF) relay system in the presence of channel estimation error, and we compare its performance with that of the direct communication cognitive radio system
Summary
The increasing demand for high data rate wireless access and services brings about the problem of spectrum scarcity [1]. All the previous works for traditional point-to-point networks [12-14] and relay-based systems [17-19] about secure wireless communication assumed perfect channel state information (CSI). For most practical wireless communication systems, training symbols are transmitted so that the receiver can estimate the channel [20]. Secure wireless communication for relay-based networks has not been addressed in the case of the presence of channel estimation error, which motivates our present work. We study the security and reliability performance of the cognitive amplify-and-forward (AF) relay system in the presence of channel estimation error, and we compare its performance with that of the direct communication cognitive radio system. The cognitive wireless system works in a slotted structure, and the whole communication from the source to the destination has two processes: the sensing process and the transmission process (Figure 2).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
