Orthogonal Time-Frequency-Space (OTFS) and Related Signaling

TL;DR

This paper analyzes OTFS signaling, its relation to other schemes like OFDM, and explores its characteristics, performance, and multiuser multiplexing capabilities, providing a comprehensive understanding of 2D time-frequency signaling methods.

Contribution

It offers a detailed analysis of OTFS, relating it to existing schemes, and introduces generalized multiplexing schemes for multiuser scenarios.

Findings

OTFS embeds OSTF, extending OFDM/SC-FDMA to 2D signaling.

OTFS characteristics can be understood through OFDM/SC-FDMA principles.

Multiuser multiplexing in OTFS is analyzed for uplink and downlink.

Abstract

The principle of orthogonal time-frequency-space (OTFS) signaling is firstly analyzed, followed by explaining that OTFS embeds another signaling scheme referred to as orthogonal short-time Fourier (OSTF). Then, the relationship among OTFS, OSTF, orthogonal frequency-division multiplexing (OFDM) and single-carrier frequency-division multiple-access (SC-FDMA) is explored, demonstrating that OSTF/OTFS are fundamentally the extensions of OFDM/SC-FDMA from one-dimensional (1D) signaling to two-dimensional (2D) signaling. Hence, the characteristics and performance of OSTF/OTFS schemes can be perceived from the well-understood OFDM/SC-FDMA schemes. Accordingly, the advantages and disadvantages of OSTF/OTFS are discussed. Furthermore, from the principles of OFDM/SC-FDMA, the multiuser multiplexing in OSTF/OTFS systems is analyzed with respect to uplink and downlink, respectively. Added on this, a range of generalized multiplexing schemes are presented, whose characteristics are briefly analyzed.