OTFS-IDMA: An Unsourced Multiple Access Scheme for Doubly-Dispersive Channels

TL;DR

This paper introduces an unsourced multiple access scheme using OTFS modulation and IDMA for high-mobility channels, enabling efficient detection and decoding in doubly-dispersive environments.

Contribution

It proposes a novel OTFS-IDMA scheme combining sparse interleaver division and compressive sensing for joint activity detection and channel estimation in high-mobility scenarios.

Findings

Demonstrates the scheme's potential in double-selective channels

Shows improved multipath diversity through MRC decoding

Highlights design tradeoffs and challenges

Abstract

We present an unsourced multiple access (UMAC) scheme tailored to high-mobility wireless channels. The proposed construction is based on orthogonal time frequency space (OTFS) modulation and sparse interleaver division multiple access (IDMA) in the delay-Doppler (DD) domain. The receiver runs a compressive-sensing joint activity-detection and channel estimation process followed by a single-user decoder which harnesses multipath diversity via the maximal-ratio combining (MRC) principle. Numerical results show the potential of DD-based uncoordinated schemes in the presence of double selectivity, while remarking the design tradeoffs and remaining challenges introduced by the proposed design.