Terminology » 6G » OTFS waveform in 6G : Understanding its benefits and drawbacks

OTFS waveform in 6G : Understanding its benefits and drawbacks

6g waveform otfs orthogonal time frequency space

OTFS is a modulation technique and is one of the waveform candidate for 6G wireless system. Let us understand its basics and explore its advantages and disadvantages in cpmparison with other multi-carrier waveforms.

What is OTFS?

The full form of OTFS is Orthogonal Time Frequency Space. It is a modulation technique designed for high mobility and time varying multipath environments. OTFS operates in delay doppler domain unlike OFDM which operates in time frequency domain. OTFS uses OFDM for physical transmission of transformed data.

How OTFS works

Following steps summarize working of OTFS technique.

  1. Mapping: Data symbols are placed in the delay Doppler domain, which represents the physical behavior of wireless channels more accurately, especially under mobility conditions.
  2. Transformation: A special 2D transformation i.e ISFFT maps those symbols into the time-frequency domain. ISFFT is the short form of Inverse Symplectic Finite Fourier Transform.
  3. Transmission: After mapping, the data symbols are modulated using conventional waveforms like OFDM for physical transmission.
  4. Reception: At the receiver, the inverse process recovers the delay doppler representation, helping to simplify equalization.

Advantages of OTFS modulation

Following are some of the benefits of OTFS modulation technique.

  • Performs significantly better than OFDM in fast moving environments due to lower BER (Bit Error Rate).
  • Can support multiple users and higher data rates with reduced overhead.
  • Utilizes full delay and Doppler diversity, improving robustness.
  • Easier to design equalizers used in receiver.

Disadvantages of OTFS

Following are some of the drawbacks of OTFS technique.

  • It has higher computational complexity as it needs 2D transforms (ISFFT, SFFT) and advanced receuvers.
  • Implementation of DTFS requires changes in baseband hardware and firmware which are not natively compatible with existing systems.
  • Channel estimation requires new algorithm techniques.
  • Additional processing steps at transmit and receive end may slightly increase latency.

Summary

OTFS offers robustness, efficiency and performance in environments where current technologies struggle. It’s a strong candidate for 6G systems, especially in high mobility scenarios.