# Secrecy Outage and Diversity Analysis of Multiple Cooperative Source-Destination Pairs

## TL;DR

This paper analyzes the physical-layer security of multi-source wireless networks with eavesdroppers, proposing a cooperation framework and a specific SD pair selection scheme, deriving secrecy outage probabilities and demonstrating maximum secrecy diversity gain.

## Contribution

It introduces the TAS-SDPS scheme for SD pair selection, providing analytical expressions for secrecy outage probability and showing its optimal secrecy diversity performance.

## Key findings

- TAS-SDPS outperforms conventional schemes in secrecy outage probability.
- The scheme achieves maximum secrecy diversity order in high MER regions.
- Analytical expressions validate the effectiveness of the proposed method.

## Abstract

We study the physical-layer security of a multiple source-destination (SD) pairs coexisting wireless network in the face of an eavesdropper, where an eavesdropper intends to wiretap the signal transmitted by the SD pairs. In order to protect the wireless transmission against eavesdropping, we propose a cooperation framework relying on two stages. Specifically, an SD pair is selected to access the total allocated spectrum using an appropriately designed scheme at the beginning of the first stage. The other source nodes (SNs) simultaneously transmit their data to the SN of the above-mentioned SD pair relying on an orthogonal way during the first stage. Then, the SN of the chosen SD pair transmits the data packets containing its own messages and the other SNs' messages to its dedicated destination node (DN) in the second stage, which in turn will forward all the other DNs' data to the application center via the core network. We conceive a specific SD pair selection scheme, termed as the transmit antenna selection aided source-destination pair selection (TAS-SDPS). We derive the secrecy outage probability (SOP) expressions for the TAS-SDPS, as well as for the conventional round-robin source-destination pair selection (RSDPS) and non-cooperative (Non-coop) schemes for comparison purposes. Furthermore, we carry out the secrecy diversity gain analysis in the high main-to-eavesdropper ratio (MER) region, showing that the TAS-SDPS scheme is capable of achieving the maximum attainable secrecy diversity order.