On the Secrecy Performance of Generalized User Selection for Interference-Limited Multiuser Wireless Networks

We investigate the secrecy performance of a multiuser diversity scheme for an interference-limited wireless network with a base-station (BS), $N$ legitimate users and an eavesdropper, in the presence of a single dominant interferer. Assuming interference dominates noise power at the eavesdropper and at each legitimate user's receiver, the BS transmits information to the legitimate user with the $k$-th best (highest) signal-to-interference ratio. We derive a closed-form expression for the secrecy outage probability for an arbitrary $N$ and an asymptotic expression for a fixed $k$ and large $N$. Furthermore, we derive a closed form asymptotic expression for the ergodic secrecy capacity of the $k$-th best user and show that it scales like $O\left(\log(N)\right)$ for a fixed $k$ and large $N$

Cooperative relaying in a SWIPT network:Asymptotic analysis using extreme value theory for non-identically distributed RVs

This paper derives the limiting distribution of the maximum end-to-end signal to noise ratio (SNR) in an opportunistic relay selection based cooperative relaying (CR) network having multiple non-identical relay links between the source and destination node. The source node is assumed to be simultaneous wireless information and power transfer (SWIPT) enabled and the relays are capable of both time splitting (TS) and power splitting (PS) based energy harvesting (EH). Contrary to the majority ofliterature in communication, which uses extreme value theory (EVT) to derive the statistics of extremes of sequences of independent and identically distributed (i.i.d.) random variables (RVs), we demonstrate how tools from EVT can be used to derive the limiting statistics of sequences of independent and non-identically distributed (i.n.i.d.) SNR RVs and hence derive the corresponding expressions for asymptotic ergodic and outage capacities. Finally, we present the utility of the asymptotic results for deciding the optimum TS and PS factors of the hybrid EH relays that (i) minimise outage probability and (ii) maximise ergodic capacity at the destination. Furthermore, we demonstrate how stochastic ordering results can be utilised for simplifying these optimisation problems