Integrated Signal Design for MIMO DFRC With Intrapulse Index Modulation

This article deals with the dual-function signal design to simultaneously achieve a desired radar beampattern and multiuser communication for a multiple-input multiple-output (MIMO) system. A novel intrapulse index modulation (I2M) methodology via jointing information embedding subpulses position options and differential phase shift keying (DPSK) is proposed to communicate, while beampattern integrated sidelobe level (ISL) is minimized to enhance radar detectability. Meanwhile, constant-envelope and communication modulation constraints are enforced to ensure compatibility with the current hardware techniques and communication demand, respectively. Besides, the mainlobe width constraint is enforced to concentrate the main energy within a specific spatial region. To tackle the resulting nonconvex and nondeterministic polynomial-hard (NP-hard) optimization problem, the coordinate descent (CD) algorithm under multiple phase constraints (MPCCD) is exploited to monotonically decrease ISL, and the consensus-alternation direction method of multipliers (C-ADMM) is utilized to attain the initial feasible sequence. Finally, numerical results highlight the effectiveness of the proposed dual-function signal design method in comparison with some of its counterparts.