Low Complexity Modem Structure for OFDM-based Orthogonal Time Frequency Space Modulation

摘要

Orthogonal time frequency space (OTFS) modulation is a two-dimensionalsignaling technique that has recently emerged in the literature to tackle thetime-varying (TV) wireless channels. OTFS deploys the Doppler-delay plane tomultiplex the transmit data where the time variations of the TV channel areintegrated over time and hence the equivalent channel relating the input andoutput of the system boils down to a time-invariant one. This signalingtechnique can be implemented on the top of a given multicarrier waveform withthe addition of precoding and post-processing units to the modulator anddemodulator. In this paper, we present discrete-time formulation of anOFDM-based OTFS system. We argue against deployment of window functions at theOTFS transmitter in realistic scenarios and thus limit any sort of windowing tothe receiver side. We study the channel impact in discrete-time providingdeeper insights into OTFS systems. Moreover, our derivations lead to simplifiedmodulator and demodulator structures that are far simpler than those in theliterature.