Towards Standardizing OTFS: A Candidate Waveform for Next-Generation Wireless Networks

2026-01-21

AI Summary

This study addresses the limitations of current 5G OFDM waveforms, which suffer from inter-carrier interference under high-Doppler conditions and exhibit reduced spectral efficiency due to cyclic prefixes, thereby falling short of 6G requirements. The work systematically investigates orthogonal time frequency space (OTFS) modulation as a promising candidate waveform for 6G, leveraging its inherent robustness to channel distortions in the delay–Doppler domain to effectively handle high-mobility and multipath environments. The authors propose an OTFS implementation compatible with existing OFDM architectures and demonstrate through performance evaluation its significant advantages in eliminating error floors under highly dynamic channels, enhancing spectral efficiency, and enabling integrated sensing and communication. These contributions provide critical technical support for the standardization of physical-layer waveforms in 6G systems.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Search and Optimization: Sampling/Simulation-based Search
• Application Domains: Mobility, Driving & Flight

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Novel mobile and WoT systems, and system-of-systems
• Search and Retrieval-Augmented AI: Retrieval-Augmented Generation (RAG) and multi-modal RAG
• User Modeling, Personalization and Recommendation: On-Device user modeling, personalization, and recommendation

Abstract

The standardization of the sixth-generation (6G) has recently commenced to address the rapidly growing demands for enhanced wireless network services. Nevertheless, existing wireless systems, particularly at the physical layer waveform level, remain inadequate for achieving the ambitious key performance indicators (KPIs) envisioned for 6G. Specifically, orthogonal frequency division multiplexing (OFDM), the widely adopted waveform in fifth-generation new radio (5G-NR) networks, suffers from inherent limitations in satisfying these stringent requirements. In practice, OFDM can experience severe inter-carrier interference (ICI), resulting in a pronounced data rate error floor caused by high Doppler shifts. Additionally, the repetitive usage of cyclic prefixes (CPs), intended to combat multipath delays, results in significant spectral inefficiency. These fundamental drawbacks pose critical obstacles to fulfilling 6G performance objectives. Orthogonal time frequency space (OTFS) modulation has recently emerged as a promising waveform candidate, addressing the aforementioned challenges by exploiting the unique characteristics of the delay-Doppler (DD) domain channel. Unlike OFDM, OTFS is inherently resilient to channel distortions induced by delay and Doppler effects, while remaining sensitive to time and frequency shifts. Such intrinsic properties are instrumental in enabling OTFS, with joint communication and sensing capabilities, to embrace, rather than combat, dynamic channel conditions. Motivated by these compelling advantages, this article investigates the feasibility and practical implementation of OTFS modulation leveraging the current OFDM-based wireless systems.

Problem

• OFDM
• 6G
• inter-carrier interference
• spectral inefficiency
• Doppler shift

Innovation

• OTFS
• Delay-Doppler domain
• 6G waveform
• Joint communication and sensing
• Doppler resilience