Challenges to subcarrier MIMO precoding and equalisation with smooth phase responses

Tools

Bakhit, M.A. and Khattak, F.A. and Schlecht, S.J. and Rice, G.W. and Weiss, S.; Thalmayer, Angelika S. and Lubke, Maximilian, eds. (2025) Challenges to subcarrier MIMO precoding and equalisation with smooth phase responses. In: 2025 28th International Workshop on Smart Antennas (WSA). ITG Workshop on Smart Antennas . IEEE, DEU, pp. 32-38. ISBN 9798350392685 (https://doi.org/10.1109/WSA65299.2025.11202801)

[thumbnail of Bakhit-etal-IEEE-WSA-2025-Challenges-to-subcarrier-MIMO-precoding-and-equalisation]
Preview
 Text. Filename: Bakhit-etal-IEEE-WSA-2025-Challenges-to-subcarrier-MIMO-precoding-and-equalisation.pdf
Accepted Author Manuscript
License: Creative Commons Attribution 4.0 logo
Download (1MB)| Preview

Abstract

Precoding for multiple-input multiple-output orthogonal frequency division multiplexing systems is often based on a per-subcarrier singular value decomposition, where phase smoothing is applied to the singular vectors that form the transmit beamformers. We show that such a smooth solution can ideally be based on an analytic singular value decomposition, but for estimated channel matrices is beset by challenges that deny a smooth or even continuous evolution of singular vectors with frequency. We show how such problems can be bypassed by admitting complex-valued singular values or fractional delays, and by exploiting a method analogous to the analytic eigenvalue decomposition to approximate ground truth analytic singular vectors from estimated channel matrices. We present examples and demonstrate some of the capabilities of a proposed algorithm through simulations.

ORCID iDs

Bakhit, M.A. ORCID logoORCID: https://orcid.org/0000-0002-2951-0325, Khattak, F.A., Schlecht, S.J., Rice, G.W. and Weiss, S. ORCID logoORCID: https://orcid.org/0000-0002-3486-7206; Thalmayer, Angelika S. and Lubke, Maximilian
CORE (COnnecting REpositories)