Transmit Waveform Design for Dual-Function Radar-Communication Systems via Hybrid Linear-Nonlinear Precoding

Abstract

This paper develops a transmit (Tx) waveform de- sign technique for dual-function radar-communication systems that provide both multiple-input multiple-output (MIMO) radar and multi-user multiple-input single-output (MU-MISO) com- munication functionalities. We propose a hybrid linear-nonlinear precoding (HLNP) signaling scheme, in which the dual-use waveform is the superposition of linearly-precoded communica- tion symbols and a nonlinearly-precoded waveform that improves the radar performance. To attain good radar Tx beampattern and waveform ambiguity properties, we focus on optimizing a weighted sum of the integrated main-lobe-to-sidelobe ratio (IMSR) of the Tx beampatttern and a novel angular waveform similarity metric, while ensuring a predefined signal-to-interference-plus- noise ratio (SINR) for each communication user. Practical con- straints are imposed on the Tx waveform, including per-antenna power and peak-to-average-power ratio (PAPR) constraints. We propose an extended feasible point pursuit successive convex ap- proximation (EFPP-SCA) algorithm to solve the resultant non- convex problem and establish its convergence properties. To re- duce the computational cost of designing a long Tx waveform, we further introduce a sub-block design technique. Numerical ex- amples indicate that the proposed HLNP provides a superior performance tradeoff between sensing and communication com- pared to conventional nonlinear precoding.