Secure Transmission in Amplify and Forward Networks for Multiple Degraded Eavesdroppers

TL;DR

This paper investigates the optimal secrecy rate in amplify-and-forward relay networks with multiple eavesdroppers, proposing analytical solutions under special conditions and an efficient quadratic programming approach for general cases.

Contribution

It introduces a novel quadratic programming method and iterative scheme to optimize secrecy rates in AF relay networks with multiple eavesdroppers.

Findings

Analytical solutions for special channel conditions.

Efficient quadratic program for general scenarios.

Validated iterative scheme through simulation results.

Abstract

We have evaluated the optimal secrecy rate for Amplify-and-Forward (AF) relay networks with multiple eavesdroppers. Assuming i.i.d. Gaussian noise at the destination and the eavesdroppers, we have devised technique to calculate optimal scaling factor for relay nodes to obtain optimal secrecy rate under both sum power constraint and individual power constraint. Initially, we have considered special channel conditions for both destination and eavesdroppers, which led us to analytical solution of the problem. Contrarily, the general scenario being a non-convex optimization problem, not only lacks an analytical solution, but also is hard to solve. Therefore, we have proposed an efficiently solvable quadratic program (QP) which provides a sub-optimal solution to the original problem. Then, we have devised an iterative scheme for calculating optimal scaling factor efficiently for both the sum power and individual power constraint scenario. Necessary figures are provided in result section to affirm the validity of our proposed solution.