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

## TL;DR

This paper analyzes the secrecy performance of a generalized user selection scheme in interference-limited multiuser wireless networks, deriving closed-form and asymptotic expressions for secrecy outage probability and ergodic secrecy capacity.

## Contribution

It provides new analytical expressions for secrecy metrics in multiuser diversity schemes under interference-limited conditions, including asymptotic behaviors as the number of users grows.

## Key findings

- Secrecy outage probability derived in closed form for arbitrary number of users.
- Asymptotic expression for secrecy outage probability when number of users is large.
- Ergodic secrecy capacity scales logarithmically with the number of users.

## Abstract

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 $N$.