Joint Communications With Fh-Mimo Radar Systems: An Extended Signaling Strategy

In this paper, we investigate the signaling strategy of {communications embedding} in frequency-hopping (FH) multiple input multiple output (MIMO) radar. Previous work that embeds communication symbols into the emission of MIMO radar with orthogonal FH waveforms via phase modulation, and waveform orthogonality compromises the transmit processing gain of the radar. Yet, the directional transmit pattern can be maintained via an appropriate design of the transmit beamforming weight vector associated with each orthogonal waveform. Moreover, communication symbols can be embedded into the complex transmit beampattern via both amplitude and phase. {In this paper}, we propose two extended signaling strategies, which fully employs the flexibility of complex beampattern in tandem with spatial modulation, to combine the merits provided by waveform diversity and transmit beamforming. As a result, the communication data rate is significantly increased, while directional transmit gain is simultaneously preserved. In order to permit the complex beampattern to be varied in accordance with communication symbols, we also propose a new approach to the beamformer design which circumvents the computationally-consuming optimization. Simulation results demonstrate the effectiveness of the proposed dual-function signaling strategies.