Hybrid-Index Modulation in Fading Channels With Integrated Sensing and Communication

Ultra-high-speed data transfer and energy efficiency are rapidly emerging as challenging requirements for communication networks. Combining hybrid-index modulation with integrated sensing and communication, this paper details a novel approach to meet this anomalous challenge and quantifies the performance over fading channels. Deriving the exact bit-error rate in fading channels results in complex mathematical functions that may not have a closed form. The moment generation function is accordingly employed, leading to simpler mathematical functions that are evaluated, and an algorithm is developed to determine the exact bit-error rate. For the proposed approach, Hexagonalquadrature amplitude, being an energy-efficient modulation, is employed for symbol transmission in vehicle-to-vehicle communication, along with phase-coding for high-resolution sensing. The integrated waveform range-azimuth resolution is analysed along with the auto-ambiguity function side-lobe response. Simulation results with discussions are provided for the bit-error rate performance of a mobile user equipment in fading channels, along with the range-azimuth response of vehicles at millimetre-wave and sub-terahertz frequencies.