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In this paper, wireless sensor network (WSN) security issue in the presence of an eavesdropper is analysed. The sensor-sink as well as sensor-eavesdropper channels are assumed to be subjected to generalized-K fading. According to the physical layer security framework, we employ round-robin, optimal sensor and cumulative distribution function-based scheduling scheme to enhance secure connection between sensor nodes and to attain low probability of intercept. Novel analytical results are given in a form of easy-to-compute analytical expressions for the intercept probability. Additionally, asymptotic closed-form expressions are derived and diversity orders of scheduling schemes are determined. Numerical results demonstrate important impacts of fading and shadowing parameters of main and wiretap links, network size and selected scheme on WSN security. Presented results are validated by independent Monte Carlo simulations.

In this work, we determine the probability of intercept for relaying wireless communication over Nakagami-m faded environment. An eavesdropper attempts to intercept the transmitted signal on link between a source and relay as well as between relay and destination. We used the decode-and forward relay to enhance the physical layer security of the system. The relay placement is analysed in order to increase the secrecy of the proposed four-node system transmission. Impacts of the path loss phenomena, fading depth, nonidentically distributed channel conditions and various signal strength transmissions are also analysed in order to realize the secure connection between the source and destination node.

We present novel closed-form expressions for the outage probability of the amplify-and-forward dual-hop semi-blind relaying channel, composed of mixed radio frequency (RF)/free space optical (FSO) links, while the relay is corrupted by both co-channel interferences and noise. The RF link is assumed to follow Nakagami-m distribution, while the FSO link is under the influence of atmospheric turbulence modelled by the Gamma–Gamma fading taking pointing errors into account. The analytical results are validated by Monte Carlo simulations. The obtained general expressions are simplified when RF link is noise-limited. The numerical results show the existence of the outage probability floor, which can be taken into account in the system design.

In this paper, we study a noise-limited low-latency decode-and-forward cooperative network set in a dynamic environment prone to link blockage. We analyse outage probability (OP) performance considering a temporally correlated fading channel between cooperating nodes employing a threshold-based protocol for internode communication. Exact and asymptotic analytical expressions for OP over Rayleigh fading, when maximal-ratio combining is applied at the destination, are derived. Asymptotic results give a better insight into outage performance at high average signal-to-noise ratio (SNR). We analyse the OP dependence on the SNR and link blockage probability and correlation coefficient of the estimated and actual internode SNR. The results illustrate that the internode protocol improves outage performance in the whole range of average uplink SNR. Internode channel correlation has a significant effect on the OP in the range of low average internode SNR. With increasing correlation, the OP increases up to an order of magnitude. The results also show that link blockage has a dominating effect on OP performance. The finite probability of all internode links being blocked reduces network performance to a single-link scenario, regardless of using the threshold-based protocol. © 2016 Zdravkovic et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/)

This paper studies the outage performance of a dual-hop amplify-and-forward (AF) relay fading channel in an interference-limited environment. The relay and destination nodes are corrupted by multiple co-channel Rayleigh interferences. New exact closed-form expressions for the outage probability for channel-state-information (CSI)--assisted relay, in which gain is dependent on previous hop CSI and interference, are derived. Monte Carlo simulations are performed to verify the obtained theoretical results. For the cases where the number of interferers at the relay and the destination node is equal, we derive novel expressions for outage probability upper and lower bounds.