Transmit design for MIMO wiretap channel with a malicious jammer

TL;DR

This paper proposes transmit design strategies for MIMO wiretap channels with a malicious jammer, addressing different levels of eavesdropper channel knowledge to optimize secrecy capacity and power allocation.

Contribution

It introduces novel algorithms for power and spatial dimension allocation under various ECSI conditions, enhancing secrecy capacity in MIMO wiretap channels with jamming.

Findings

Algorithms effectively improve secrecy capacity.

Methods are computationally efficient.

Strategies adapt to different ECSI knowledge levels.

Abstract

In this paper, we consider the transmit design for multi-input multi-output (MIMO) wiretap channel including a malicious jammer. We first transform the system model into the traditional three-node wiretap channel by whitening the interference at the legitimate user. Additionally, the eavesdropper channel state information (ECSI) may be fully or statistically known, even unknown to the transmitter. Hence, some strategies are proposed in terms of different levels of ECSI available to the transmitter in our paper. For the case of unknown ECSI, a target rate for the legitimate user is first specified. And then an inverse water-filling algorithm is put forward to find the optimal power allocation for each information symbol, with a stepwise search being used to adjust the spatial dimension allocated to artificial noise (AN) such that the target rate is achievable. As for the case of statistical ECSI, several simulated channels are randomly generated according to the distribution of ECSI. We show that the ergodic secrecy capacity can be approximated as the average secrecy capacity of these simulated channels. Through maximizing this average secrecy capacity, we can obtain a feasible power and spatial dimension allocation scheme by using one dimension search. Finally, numerical results reveal the effectiveness and computational efficiency of our algorithms.