SNR maximization in beyond diagonal RIS-assisted single and multiple antenna links

Reconfigurable intelligent surface (RIS) architectures not limited to diagonal phase shift matrices have recently been considered to increase their flexibility in shaping the wireless channel. One of these beyond-diagonal RIS or BD-RIS architectures leads to a unitary and symmetric RIS matrix. In th...

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Detalles Bibliográficos
Autores: Santamaría Caballero, Luis Ignacio|||0000-0003-0040-7436, Soleymani, Mohammad, Jorswieck, Eduard, Gutiérrez Terán, Jesús
Tipo de recurso: artículo
Fecha de publicación:2023
País:España
Institución:Universidad de Cantabria (UC)
Repositorio:UCrea Repositorio Abierto de la Universidad de Cantabria
Idioma:inglés
OAI Identifier:oai:repositorio.unican.es:10902/29771
Acceso en línea:https://hdl.handle.net/10902/29771
Access Level:acceso abierto
Palabra clave:Reconfigurable intelligent surface
Takagi factorization
Optimization
Multiple antennas
Multiple access channel
Descripción
Sumario:Reconfigurable intelligent surface (RIS) architectures not limited to diagonal phase shift matrices have recently been considered to increase their flexibility in shaping the wireless channel. One of these beyond-diagonal RIS or BD-RIS architectures leads to a unitary and symmetric RIS matrix. In this letter, we consider the problem of maximizing the signal-to-noise ratio (SNR) in single and multiple antenna links assisted by a BD-RIS. The Max-SNR problem admits a closed-form solution based on the Takagi factorization of a certain complex and symmetric matrix. This allows us to solve the max-SNR problem for SISO, SIMO, and MISO channels.