Enhancing Secrecy with Multi-Antenna Transmission in Wireless Ad Hoc Networks

TL;DR

This paper explores multi-antenna transmission schemes, including sectoring and beamforming, to enhance physical-layer security in wireless ad hoc networks by analyzing their outage performance and secrecy throughput.

Contribution

It provides a statistical analysis and tradeoff evaluation of artificial noise schemes, comparing sectoring and beamforming for secrecy enhancement in ad hoc networks.

Findings

Beamforming outperforms sectoring with power optimization.

Optimal power allocation differs between sectoring and beamforming.

Beamforming is more effective when the number of antennas is moderate.

Abstract

We study physical-layer security in wireless ad hoc networks and investigate two types of multi-antenna transmission schemes for providing secrecy enhancements. To establish secure transmission against malicious eavesdroppers, we consider the generation of artificial noise with either sectoring or beamforming. For both approaches, we provide a statistical characterization and tradeoff analysis of the outage performance of the legitimate communication and the eavesdropping links. We then investigate the networkwide secrecy throughput performance of both schemes in terms of the secrecy transmission capacity, and study the optimal power allocation between the information signal and the artificial noise. Our analysis indicates that, under transmit power optimization, the beamforming scheme outperforms the sectoring scheme, except for the case where the number of transmit antennas are sufficiently large. Our study also reveals some interesting differences between the optimal power allocation for the sectoring and beamforming schemes.