Joint Optimization for Security and Reliability in Round-Trip Transmissions for URLLC services

TL;DR

This paper proposes a joint optimization framework for enhancing security and reliability in URLLC by optimizing redundant bits and blocklength in round-trip transmissions, using globally optimal and efficient algorithms validated through simulations.

Contribution

It introduces a novel joint optimization model for security and reliability in PLS for URLLC, with new algorithms for efficient solution derivation.

Findings

The globally optimal solution effectively minimizes leakage-failure probability.

The proposed algorithms significantly improve computational efficiency.

Simulation results confirm the practical applicability for future URLLC services.

Abstract

Physical layer security (PLS) is a potential solution for secure and reliable transmissions in future Ultra-Reliable and Low-Latency Communications (URLLC). This work jointly optimizes redundant bits and blocklength allocation in practical round-trip transmission scenarios. To minimize the leakage-failure probability, a metric that jointly characterizes security and reliability in PLS, we formulate an optimization problem for allocating both redundant bits and blocklength. By deriving the boundaries of the feasible set, we obtain the globally optimal solution for this integer optimization problem. To achieve more computationally efficient solutions, we propose a block coordinate descent (BCD) method that exploits the partial convexity of the objective function. Subsequently, we develop a majorization-minimization (MM) algorithm through convex approximation of the objective function, which further improves computational efficiency. Finally, we validate the performance of the three proposed approaches through simulations, demonstrating their practical applicability for future URLLC services.