Linear Precoder Design for a MIMO Gaussian Wiretap Channel with Full-Duplex Source and Destination Nodes

TL;DR

This paper designs linear precoders for a MIMO Gaussian wiretap channel with full-duplex nodes, optimizing for maximum sum secrecy degrees of freedom, and demonstrates the effectiveness of full-duplex operation in enhancing secrecy rates.

Contribution

It introduces a cooperative secrecy transmission scheme and derives a closed-form solution for the maximum sum secrecy degrees of freedom in full-duplex MIMO wiretap channels.

Findings

Full-duplex operation improves secrecy transmission rates.

A closed-form expression for maximum sum S.D.o.F. is provided.

The proposed scheme achieves the maximum sum S.D.o.F. in the system.

Abstract

We consider linear precoder design for a multiple-input multiple-output (MIMO) Gaussian wiretap channel, which comprises two legitimate nodes, i.e., Alice and Bob, operating in Full-Duplex (FD) mode and exchanging confidential messages in the presence of a passive eavesdropper. Using the sum secrecy degrees of freedoms (sum S.D.o.F.) as reliability measure, we formulate an optimization problem with respect to the precoding matrices. In order to solve this problem, we first propose a cooperative secrecy transmission scheme, and prove that its feasible set is sufficient to achieve the maximum sum S.D.o.F.. Based on that feasible set, we then determine the maximum achievable sum S.D.o.F. in closed form, and provide a method for constructing the precoding matrix pair which achieves the maximum sum S.D.o.F.. Results show that, the FD based network provides an attractive secrecy transmission rate performance.