Energy Efficient Dual-Functional Radar-Communication: Rate-Splitting Multiple Access, Low-Resolution DACs, and RF Chain Selection

TL;DR

This paper proposes an energy-efficient dual-functional radar-communication system using rate-splitting multiple access, low-resolution DACs, and RF chain selection, optimizing energy use while maintaining performance.

Contribution

It introduces a novel optimization framework for maximizing energy-efficiency in dual-functional systems considering RF chain selection and low-resolution DACs, with a new algorithm for solving the problem.

Findings

Rate-Splitting Multiple Access improves energy-efficiency over Space Division Multiple Access.

Fewer RF chains are needed with Rate-Splitting for optimal energy use.

Numerical results validate the effectiveness of the proposed approach.

Abstract

Dual-Functional Radar-Communication systems enhance the benefits of communications and radar sensing by jointly implementing these on the same hardware platform and using the common RF resources. An important and latest concern to be addressed in designing such Dual-Functional Radar-Communication systems is maximizing the energy-efficiency. In this paper, we consider a Dual-Functional Radar-Communication system performing simultaneous multi-user communications and radar sensing, and investigate the energy-efficiency behaviour with respect to active transmission elements. Specifically, we formulate a problem to find the optimal precoders and the number of active RF chains for maximum energy-efficiency by taking into consideration the power consumption of low-resolution Digital-to-Analog Converters on each RF chain under communications and radar performance constraints. We consider Rate-Splitting Multiple Access to perform multi-user communications with perfect and imperfect Channel State Information at Transmitter. The formulated non-convex optimization problem is solved by means of a novel algorithm. We demonstrate by numerical results that Rate Splitting Multiple Access achieves an improved energy-efficiency by employing a smaller number of RF chains compared to Space Division Multiple Access, owing to its generalized structure and improved interference management capabilities.