Finite State Multiple-Access Wiretap Channel with Delayed Feedback

TL;DR

This paper investigates how delayed feedback can enhance secure communication rates in a finite state multiple-access wiretap channel, revealing that feedback significantly improves secrecy capacity in such systems.

Contribution

It introduces the FS-MAC-WT model with delayed feedback and demonstrates that utilizing full delayed feedback increases the secrecy rate region.

Findings

Delayed feedback improves secrecy capacity.

Full use of feedback enlarges the secrecy rate region.

Results illustrated with a degraded Gaussian fading example.

Abstract

Recently, it has been shown that the time-varying multiple-access channel (MAC) with perfect channel state information (CSI) at the receiver and delayed feedback CSI at the transmitters can be modeled as the finite state MAC (FS-MAC) with delayed state feedback, where the time variation of the channel is characterized by the statistics of the underlying state process. To study the fundamental limit of the secure transmission over multi-user wireless communication systems, we re-visit the FS-MAC with delayed state feedback by considering an external eavesdropper, which we call the finite state multiple-access wiretap channel (FS-MAC-WT) with delayed feedback. The main contribution of this paper is to show that taking full advantage of the delayed channel output feedback helps to increase the secrecy rate region of the FS-MAC-WT with delayed state feedback, and the results of this paper are further illustrated by a degraded Gaussian fading example.