A 5G network’s use-case in the Internet of Things (IoT) is a breakthrough, offering networks the ability to handle billions of connected devices with the proper blend of speed, latency, and cost. The IoT networks implemented in highspeed scenarios like intra and inter-vehicular communications in autonomous driving vehicles, high-speed vehicles, and trains will experience a Doppler effect. Orthogonal frequency-division multiplexing, popular transmission technology for existing newradio IoT (NR-IoT), is limited in providing reliable connections in high-speed vehicular scenarios. The performance of such system degrades with higher-order antenna configuration due to the lack of channel state information in highly mobile environments. The recently proposed orthogonal time-frequency space (OTFS) modulation is a strong contender that can handle high mobility but requires efficient transceiver design to be deployed in vehicular NR-IoT (V-IoT) systems. To conserve the resources and minimize the air time of the devices, we have proposed an embedded pilot design in the Delay-Doppler domain for the V-IoT systems. In the designed frame structure, the pilot’s position is optimized as per the vehicle speed to maximize the spectral efficiency of the system. The increase in spectral efficiency is at the cost of interference in the channel search region of the received Delay-Doppler domain OTFS signal. So a new joint estimator and low-complex detector is proposed to handle the interference. The proposed efficient transceiver design with the spectral efficient pilot patterns allow us to conserve resources and remove complex encoder-decoders like the low-density parity check in NR-IoT.
This work was supported by the Ministry of Electronics and Information Technology, India, through the Program “Next Generation Wireless Research and Standardization on 5G and Beyond” (Sanction Letter No: 13(44)/2020-CC&BT, 30-07-2021).