# Physical Layer Security in Wireless Ad Hoc Networks Under A Hybrid Full-/Half-Duplex Receiver Deployment Strategy

## TL;DR

This paper proposes a hybrid full-/half-duplex receiver deployment strategy in wireless ad hoc networks to enhance physical layer security by optimizing the fraction of full-duplex receivers, balancing reliability and secrecy.

## Contribution

It introduces a novel hybrid FD/HD deployment strategy and derives analytical expressions for security metrics, optimizing network security performance.

## Key findings

- Optimal fraction of FD receivers improves security trade-offs.
- Closed-form expressions for key security metrics are derived.
- The strategy significantly enhances network security performance.

## Abstract

This paper studies physical layer security in a wireless ad hoc network with numerous legitimate transmitter-receiver pairs and eavesdroppers. A hybrid full-/half-duplex receiver deployment strategy is proposed to secure legitimate transmissions, by letting a fraction of legitimate receivers work in the full-duplex (FD) mode sending jamming signals to confuse eavesdroppers upon their information receptions, and letting the other receivers work in the half-duplex mode just receiving their desired signals. The objective of this paper is to choose properly the fraction of FD receivers for achieving the optimal network security performance. Both accurate expressions and tractable approximations for the connection outage probability and the secrecy outage probability of an arbitrary legitimate link are derived, based on which the area secure link number, network-wide secrecy throughput and network-wide secrecy energy efficiency are optimized respectively. Various insights into the optimal fraction are further developed and its closed-form expressions are also derived under perfect self-interference cancellation or in a dense network. It is concluded that the fraction of FD receivers triggers a non-trivial trade-off between reliability and secrecy, and the proposed strategy can significantly enhance the network security performance.