Compatibility study of Orthogonal Time Frequency Space and 5G NR based on Open Source RAN

Orthogonal Time Frequency Space (OTFS) is a novel multicarrier modulation scheme. The study leverages the delay-Doppler domain for the representation and processing of signals. OTFS has been shown to offer superior performance over conventional Orthogonal Frequency Division Multiplexing (OFDM) in high-mobility scenarios, where the channel exhibits severe Doppler spread. In this paper, we investigate the feasibility and challenges of integrating OTFS technology with the 5G NR standard, using the OpenAirInterface (OAI) as an experimental platform for system-level simulation. We present the design and implementation of two OTFS modules on the OAI platform, as well as a Doppler channel simulator that can emulate realistic channel conditions for OTFS transmissions. We also propose an OTFS frame structure that is compatible with the NR physical (PHY) layer specifications and protocols. Through extensive simulations and experiments, we demonstrate that our OTFS system can be compatible with the 5G NR protocol stack and achieve higher spectral efficiency and robustness against Doppler effects than the OFDM system.