Integrated Narrowband Orthogonal Signal Set Design for MIMO DFRC System

This paper focuses on the design of a dual-function narrowband orthogonal signal set with low Cross- and Auto-correlation Peak Sidelobe Levels (C/A-PSL) to simultaneously achieve active detection and multi-user communication for the Multiple Input Multiple Output (MIMO) Dual-Function Radar and Communication (DFRC) system. A novel Intra pulse Index and Phase (Intra-IP) methodology via jointing Information embedding Subpulses (InSps) positions selection and Differential Phase Shift Keying (DPSK) is proposed to communicate. This modulation method enables the transmission of different information to distinct users in the same spatial direction. The orthogonal signal set design problem is formulated based on minimizing C/A-PSL while considering the constant envelope and phase constraints. To tackle the resulting nonconvex and NP-hard optimization problem, the Special Majorization-minimization Coordinate Descent (SM-CD) algorithm is exploited to monotonically decrease C/A-PSL. Finally, numerical results demonstrate the effectiveness of the proposed Intra-IP modulation method in comparison with some counterparts.