A Superposition Signaling Scheme for Integrated Sensing and Communication

2026-07-14

AI Summary

This work addresses the joint optimization of communication rate and sensing performance in orthogonal frequency-division multiplexing (OFDM) integrated sensing and communication systems. Under constraints on transmit power and signal kurtosis, the authors propose a tunable superposition transmission strategy that combines a constant-modulus waveform—optimal for sensing—with a complex Gaussian signal—optimal for communication—and employs successive decoding to precisely characterize the achievable rate. Theoretical analysis reveals that capacity-achieving inputs exhibit a concentric multi-ring discrete-amplitude structure, which inspires a practical signaling scheme with simple architecture yet near-capacity performance. Numerical results demonstrate that the proposed scheme deviates from the theoretical capacity by at most approximately 0.043 bits across various operating conditions, thereby closely approaching the fundamental performance limit.

Abstract

We investigate the capacity of an integrated sensing and communication system operating with orthogonal frequency division multiplexing, where the integrated sidelobe level of the transmit signal is adopted as an input cost. The problem is reduced to the capacity of a complex additive white Gaussian noise channel under power and kurtosis constraints. The sensing-optimal and communication-optimal operating points are characterized by circularly symmetric constant-modulus and complex Gaussian inputs, respectively, while the capacity-achieving input in between has discrete amplitude support with a concentric multi-ring geometry. We propose the superposition of the two extremal inputs as a simple and tunable signaling strategy, whose rate admits an exact expression via successive decoding. Numerical results show that the proposed strategy attains a worst-case gap of approximately 0.043 bits to the capacity.

Problem

• Integrated Sensing and Communication
• OFDM
• Capacity
• Signal Design
• Kurtosis Constraint

Innovation

• Integrated Sensing and Communication
• Superposition Signaling
• Capacity-Achieving Input
• Multi-Ring Constellation
• Kurtosis Constraint