Optimization of Code Rates in SISOME Wiretap Channels

TL;DR

This paper introduces a new framework and the effective secrecy throughput metric for optimizing wiretap code rates in SISOME channels, especially when the eavesdropper's channel capacity is unknown, without relying on traditional secrecy constraints.

Contribution

It proposes a novel performance metric and provides practical methods for determining wiretap code rates under various channel knowledge scenarios, including passive eavesdropping.

Findings

Effective secrecy throughput (EST) captures reliability and secrecy.

Methods for adaptive and fixed-rate schemes are developed.

Solutions work even when eavesdropper's channel info is unavailable.

Abstract

We propose a new framework for determining the wiretap code rates of single-input single-output multi-antenna eavesdropper (SISOME) wiretap channels when the capacity of the eavesdropper's channel is not available at the transmitter. In our framework we introduce the effective secrecy throughput (EST) as a new performance metric that explicitly captures the two key features of wiretap channels, namely, reliability and secrecy. Notably, the EST measures the average rate of the confidential information transmitted from the transmitter to the intended receiver without being eavesdropped on. We provide easy-to-implement methods to determine the wiretap code rates for two transmission schemes: 1) adaptive transmission scheme in which the capacity of the main channel is available at the transmitter and 2) fixed-rate transmission scheme in which the capacity of the main channel is not available at the transmitter. Such determinations are further extended into an absolute-passive eavesdropping scenario where even the average signal-to-noise ratio of the eavesdropper's channel is not available at the transmitter. Notably, our solutions for the wiretap code rates do not require us to set reliability or secrecy constraints for the transmission within wiretap channels.