Vehicular-IoT Modem design

The Vehicular-IoT (V-IoT) system is a spectrally efficient low complex OTFS modulation-based resource-constrained device communication in a high-mobility environment.

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. A vehicular-IoT (V-IoT) system is designed for a high-mobility environment that comprises at least one transmitter configured to transmit bit stream involving adaptive orthogonal time frequency space (OTFS) frame with selectively embedded pilot depending on mobility conditions for improving spectral efficiency and at least one receiver configured to dispose of onto IoT devices with a low-complex iterative detector for receiving thus transmitted bit stream. The receiver is configured to update the transmitter about its mobility condition through a control channel. 

According to the system requirement, the transmitter must generate the adaptive OTFS frame, and the frame design information must be shared with the receiver via the control channel for reliable link establishment. We have presented a strategic plot for selecting a pilot design to create the adaptive transmitter frame for the OTFS-based V-IoT system. We have used different parameters like velocity, pilot-to-data power ratio (PDR), complementary cumulative distribution function (CCDF) (threshold such that probability (peak to average ratio (PAPR) > threshold) starts falling from 1), spectral efficiency, and SNR required for reliable communication (i.e., to attain BER =10^-5), for pilot design selection. The parameters in each axis show improvement while moving away from the centre. It can be observed from the figure that the proposed adaptive pilot design scheme - low speed (ADS-LS) (i.e., speed = 120 km/hr) is optimum in terms of the above-mentioned parameters as it has the highest area in the plot. Although the proposed EMS, which is also utilized for a vehicle speed of 120 km/hr, is spectrally more efficient than the proposed ADS-LS, it heavily lags in terms of SNR to achieve reliable performance. When moving to a very high velocity, i.e., ADS-HS and ADS-VHS, reliable performance cannot be achieved for any SNR. However, the proposed ADS-HS and ADS-VHS can be selected depending on the system's spectral efficiency, power availability, and PAPR requirement of the power amplifier to avoid nonlinearity issues. Moreover, if the system wants reliable communication at a higher vehicular speed at the cost of spectral efficiency and other mentioned parameters, it can choose the embedded pilot design. So based on the requirements, the user needs to adapt the respective frame design.

Outcomes:

• 1. Ch Santosh Reddy, Preety Priya, Debarati Sen, Chetna Singhal, Method and system for spectrally efficient pilot and detector design in the Delay-Doppler domain for OTFS-based NR (new radio) IoT and massive machine-to-machine (M2M) communications, United States Patent, Publication No.: US 2023/0370316 A1, pub dated November 16, 2023

  2. Ch Santosh Reddy, Preety Priya, Debarati Sen, Chetna Singhal, Method and system for spectrally efficient pilot and detector design in the Delay-Doppler domain for OTFS-based NR (new radio) IoT and massive machine-to-machine (M2M) communications, Indian Patent application No. 202231027219, dated May 11, 2022

  3. Ch Santosh Reddy, Preety Priya, Debarati Sen, Chetna Singhal, Spectral Efficient Modem Design with OTFS Modulation for Vehicular-IoT System, IEEE Internet of Things Journal, vol. 10, no. 3, pp. 2444-2458, 1 Feb.1, 2023, DOI: 10.1109/JIOT.2022.3211531.  [Paper]

  4. Ch Santosh Reddy, Debarati Sen, Chetna Singhal, Performance Analysis of NR-based Vehicular IoT System with OTFS Modulation, 2021 IEEE 94th Vehicular Technology Conference (VTC2021-Fall). Sep 27, 2021. [Paper]