@conference{10902/35434,
year = {2024},
url = {https://hdl.handle.net/10902/35434},
abstract = {This paper addresses the problem of maximizing the capacity of a multiple-input multiple-output (MIMO) link assisted by a beyond-diagonal reconfigurable intelligent surface (BD-RIS). We maximize the capacity by alternately optimizing the transmit covariance matrix, and the BD-RIS scattering matrix, which, according to network theory, should be unitary and symmetric. These constraints make the optimization of BD-RIS more challenging than that of diagonal RIS. To find a stationary point of the capacity we apply an iterative algorithm in the manifold of unitary matrices. This leads to an efficient algorithm that always improves the capacity obtained by a diagonal RIS. Through simulation examples, we study the capacity improvement provided by a passive BD-RIS architecture over the conventional RIS model in which the phase shift matrix is diagonal.},
organization = {This work is supported by the European Commission’s Horizon Europe, Smart Networks and Services Joint Undertaking program under grant agreement 101139282, 6G-SENSES project. The work of I. Santamaria was also supported under grant PID2022-137099NB-C43 (MADDIE) funded by MICIU/AEI/10.13039/501100011033 and FEDER, UE.},
publisher = {Institute of Electrical and Electronics Engineers, Inc.},
publisher = {IEEE 25th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC), Lucca, Italy, 2024, 936-940},
title = {MIMO capacity maximization with beyond-diagonal RIS},
author = {Santamaría Caballero, Luis Ignacio and Soleymani, Mohammad and Jorswieck, Eduard and Gutiérrez, Jesús},
}