SPS SA-TWG Webinar: Communication and Radar Sensing using Zak-OTFS Waveform (Pulsone)

Date: 10 July 2024
Time: 10:00 AM ET (New York Time)
Speaker(s): Prof. A. Chockalingam

This webinar is the next in a series by the IEEE Synthetic Aperture Technical Working Group (SA-TWG)

Abstract

6G propagation environments are expected to be challenging in terms of extreme Dopplers (few kHz to tens of kHz) for which communication waveforms that are robust in extreme time-selective channels are crucial. Also, the convergence of communication and radar sensing in 6G and beyond (inspired by the developments in intelligent transportation systems) has focused research attention on the design of waveforms that can simultaneously support both communication and radar sensing. Modulation and channel representation in the delay-Doppler (DD) domain is an effective approach to mitigate the effects of swift time variations in the channel and achieve robust communication performance.

Also, DD parameter estimation (for range and velocity estimation) is a natural and fundamental task in radar sensing, which is analogous to the task of DD channel estimation in communication systems that use DD domain modulation. Orthogonal time frequency space (OTFS) waveform, a waveform defined in the DD domain, can efficiently serve both the communication as well as the radar sensing needs. This talk will focus on Zak transform based OTFS waveform and highlight its suitability for communication and radar sensing. The basic Zak-OTFS waveform is a quasi-periodic pulse in the DD domain, whose time domain realization is a train of time domain pulses modulated by a tone (hence called as a `pulsone’). As a communication waveform, pulsones offer the beneficial attributes of non-fading and predictability of input-output relation, leading to robust bit error performance in rapidly time-varying channels. Also, they have good localization characteristics in the DD domain which is beneficial in radar sensing. The optimum operating regime for both communication and radar sensing turns out to be the same, i.e., when the delay period and Doppler period of the Zak-OTFS waveform are larger than the delay spread and Doppler spread of the channel, respectively, a condition referred to as the crystallization condition.

Biography

A. Chockalingam is a professor in the department of ECE, Indian Institute of Science (IISc), Bangalore. He obtained the Ph.D. degree from the same department in 1993. He was a postdoctoral fellow and an assistant project scientist in the department of ECE, UC San Diego from 1993 to 1996. He was with Qualcomm, San Diego as a Staff Engineer/Manager from 1996 to 1998. Since 1998 he has been a faculty at IISc, Bangalore. He has served as an editor/associate editor of IEEE Trans. on Wireless Communications, IEEE Trans. Vehicular Technology, IEEE JSAC, and IEEE JSTSP. He is an author of the book on “Large MIMO Systems” published by Cambridge University Press in 2014. He is also an author of the upcoming book on “OTFS Modulation – Theory and Applications” to be published by IEEE Press-Wiley in September 2024.