  This paper develops an efficient index modulation (IM) approach for the joint
radar-communication (JRC) system based on a multi-carrier multiple-input
multiple-output (MIMO) radar. The communication information is embedded into
the transmitted radar pulses by selecting the corresponding indices of the
carrier frequencies and antenna allocations, providing two degrees of freedom.
Our contribution involves the development of a novel codebook based minimum
Euclidean distance (MED) maximization and a constellation randomization
pre-scaling (CRPS) scheme for efficient IM-JRC transmission. It can be inferred
that the IM approach integrating the CRPS scheme followed by the codebook
design maximizes the signal-to-noise ratio gain. The numerical results support
the effectiveness of the proposed approach and show enhanced bit error rate
performance when compared to the existing baseline.

Signal Processing