Frequency-Dependent Beamforming and Beam Training for XL-MIMO With Practical TTDs

Research output: Contribution to journalResearch articleContributedpeer-review

Abstract

The integration of extremely large (XL) antenna arrays with ultra wideband (UWB) communication is pivotal for next-generation networks. However, the multitude of candidate beams renders conventional analog phase shifters (APSs)-based training prohibitively costly, necessitating true-time delay (TTD)-based frequency-dependent beamforming. We design a codebook mapping distinct orthogonal frequency-division multiplexing (OFDM) subcarriers to unique spatial angles, enabling full angular coverage within a single OFDM symbol. To address practical TTD limitations–finite delay range and resolution–we propose a multi-stage delay-phase-precoding (MSDPP) architecture that mitigates hardware-induced distortions. Simulations demonstrate that MSDPP achieves near-optimal spectral efficiency (SE) with at least a 2dB gain over state-of-the-art designs, alongside up to 63% higher energy efficiency (EE).

Details

Original languageEnglish
Pages (from-to)1315-1319
Number of pages5
JournalIEEE Wireless Communications Letters
Volume15
Publication statusPublished - 12 Jan 2026
Peer-reviewedYes

External IDs

Scopus 105028033322
ORCID /0000-0002-0738-556X/work/205334972
ORCID /0000-0002-1315-7635/work/205336245
ORCID /0000-0001-7075-8990/work/205336898

Keywords

Sustainable Development Goals

Keywords

  • Beam training, extremely large (XL)-MIMO, frequency-dependent beamforming, true-time delay (TTD), ultra wideband (UWB)