Joint Correlation-Sidelobe Suppression and Doppler-Resilient Complementary Sets of Sequences Design for ISAC Systems

Abstract

Complementary sets of sequences (CSSs) play an important role in target sensing for integrated sensing and communication (ISAC) systems due to the favorable correlation properties. In this paper, we investigate the design of unimodular CSSs for low-velocity moving-target sensing in the presence of Doppler shifts. Unlike conventional complementary sequences, whose correlation performance degrades significantly under Doppler mismatch, the proposed design explicitly accounts for both correlation sidelobe suppression and Doppler resilience. To this end, we formulate a unified optimization problem that minimizes the peak sidelobe level while shaping the ambiguity function through the Doppler-dependent correlation matrix of the CSS. To efficiently handle the resulting nonconvex problem, we develop an alternating direction method of multipliers-based algorithm with auxiliary variables, combined with the majorization-minimization framework. Numerical results show that the proposed method achieves low complementary autocorrelation sidelobes and improved Doppler robustness, and provides reliable sensing performance for low-velocity moving targets in ISAC scenarios.