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6G OFDM Communications with High Mobility Transceivers and Scatterers via Angle-Domain Processing and Deep Learning

Mauro Marchese, Musa Furkan Keskin, Henk Wymeersch, Pietro Savazzi

TL;DR

This work introduces a DoA-aided OFDM receiver that leverages angle-domain path separation to mitigate Doppler-induced ICI in 6G-like high-mobility scenarios. It combines block-type pilots for DoA, delay, and gain estimation with a decision-directed Doppler refinement loop, offering two initial Doppler strategies (EVM-based and DL-based) and a per-path processing pipeline (time-domain ICI cancellation, frequency-domain delay compensation, and MR combining). The DL-based Doppler initialization demonstrates near-constant BER up to 1000 km/h with low pilot overhead and modest complexity, highlighting the approach's mobility resilience. The proposed framework advances practical, high-m mobility wireless links by transforming a doubly-dispersive channel into parallel single-Doppler channels through angular processing and data-driven initialization. The findings have significant implications for robust 6G communications in scenarios with fast-moving transceivers and rich scattering.

Abstract

High-mobility communications, which are crucial for next-generation wireless systems, cause the orthogonal frequency division multiplexing (OFDM) waveform to suffer from strong intercarrier interference (ICI) due to the Doppler effect. In this work, we propose a novel receiver architecture for OFDM that leverages the angular domain to separate multipaths. A block-type pilot is sent to estimate direction-of-arrivals (DoAs), propagation delays, and channel gains of the multipaths. Subsequently, a decision-directed (DD) approach is employed to estimate and iteratively refine the Dopplers. Two different approaches are investigated to provide initial Doppler estimates: an error vector magnitude (EVM)-based method and a deep learning (DL)-based method. Simulation results reveal that the DL-based approach allows for constant bit error rate (BER) performance up to the maximum 6G speed of 1000 km/h.

6G OFDM Communications with High Mobility Transceivers and Scatterers via Angle-Domain Processing and Deep Learning

TL;DR

This work introduces a DoA-aided OFDM receiver that leverages angle-domain path separation to mitigate Doppler-induced ICI in 6G-like high-mobility scenarios. It combines block-type pilots for DoA, delay, and gain estimation with a decision-directed Doppler refinement loop, offering two initial Doppler strategies (EVM-based and DL-based) and a per-path processing pipeline (time-domain ICI cancellation, frequency-domain delay compensation, and MR combining). The DL-based Doppler initialization demonstrates near-constant BER up to 1000 km/h with low pilot overhead and modest complexity, highlighting the approach's mobility resilience. The proposed framework advances practical, high-m mobility wireless links by transforming a doubly-dispersive channel into parallel single-Doppler channels through angular processing and data-driven initialization. The findings have significant implications for robust 6G communications in scenarios with fast-moving transceivers and rich scattering.

Abstract

High-mobility communications, which are crucial for next-generation wireless systems, cause the orthogonal frequency division multiplexing (OFDM) waveform to suffer from strong intercarrier interference (ICI) due to the Doppler effect. In this work, we propose a novel receiver architecture for OFDM that leverages the angular domain to separate multipaths. A block-type pilot is sent to estimate direction-of-arrivals (DoAs), propagation delays, and channel gains of the multipaths. Subsequently, a decision-directed (DD) approach is employed to estimate and iteratively refine the Dopplers. Two different approaches are investigated to provide initial Doppler estimates: an error vector magnitude (EVM)-based method and a deep learning (DL)-based method. Simulation results reveal that the DL-based approach allows for constant bit error rate (BER) performance up to the maximum 6G speed of 1000 km/h.
Paper Structure (25 sections, 16 equations, 2 figures, 1 table, 2 algorithms)

This paper contains 25 sections, 16 equations, 2 figures, 1 table, 2 algorithms.

Table of Contents

  1. Introduction
  2. System Model
  3. Single-Antenna OFDM Transmitter
  4. Observation Model at the Multi-Antenna Receiver
  5. Proposed DoA-Aided OFDM Receiver
  6. Path Separation via Angle-domain Matched Filter
  7. Data Detection: Delay/ICI Compensation
  8. Cancellation via Time-Domain Single-tap
  9. Delay compensation via Frequency-Domain Single-tap
  10. Maximum ratio combining
  11. Channel Parameter Estimation
  12. Angle Estimation
  13. Angle-domain MF
  14. Delay Estimation
  15. Gain Estimation
  16. ...and 10 more sections

Figures (2)

  • Figure 1: The OFDM system including a single-antenna transmitter, multiple reflectors (either static or mobile) and the proposed multi-antenna DoA-aided receiver containing a Doppler initialization module for coarse Doppler estimation from the received block-type pilot (zero Doppler, error vector magnitude or deep learning).
  • Figure 2: Simulation results for varying Doppler, SNR, and UE speed.