  Integrated sensing and communication (ISAC) is a promising technology in
future wireless systems owing to its efficient hardware and spectrum
utilization. In this paper, we consider a multi-input multi-output (MIMO)
orthogonal frequency division multiplexing (OFDM) ISAC system and propose a
novel waveform design to provide better radar ranging performance by taking
range sidelobe suppression into consideration. In specific, we aim to design
MIMO-OFDM dual-function waveform to minimize its integrated sidelobe level
(ISL) while satisfying the quality of service (QoS) requirements of multi-user
communications and the transmit power constraint. To achieve a lower ISL, the
symbol-level precoding (SLP) technique is employed to fully exploit the degrees
of freedom (DoFs) of the waveform design in both temporal and spatial domains.
An efficient algorithm utilizing majorization-minimization (MM) framework is
developed to solve the non-convex waveform design problem. Simulation results
reveal radar ranging performance improvement and demonstrate the benefits of
the proposed SLP-based low-range-sidelobe waveform design in ISAC systems.
