8 papers
Riemannian optimization on the manifold of unitary and symmetric matrices with application to BD-RIS-assisted systems
Ignacio Santamaria, Mohammad Soleymani, Eduard Jorswieck +2
In this paper, we rigorously characterize for the first time the manifold of unitary and symmetric matrices, deriving its tangent space and its geodesics. The resulting parameteriz…
Spectral-Energy Efficiency Tradeoff of Nearly-Passive RIS in MIMO URLLC Downlink: Diagonal vs. Beyond Diagonal
Mohammad Soleymani, Alessio Zappone, Eduard Jorswieck +2
This paper investigates the spectral and energy efficiency (EE) tradeoff of nearly-passive (NP), both locally and globally NP (GNP), reconfigurable intelligent surface (RIS), consi…
STAR-RIS-aided RSMA for the URLLC multi-user MIMO Downlink
Mohammad Soleymani, Ignacio Santamaria, Eduard Jorswieck +2
Rate splitting multiple access (RSMA) is intrinsically amalgamated with simultaneously transmitting and reflecting (STAR) reconfigurable intelligent surfaces (RIS) to enhance energ…
Energy Efficiency Optimization of Finite Block Length STAR-RIS-aided MU-MIMO Broadcast Channels
Mohammad Soleymani, Ignacio Santamaria, Eduard Jorswieck +2
Energy-efficient designs are proposed for multi-user (MU) multiple-input multiple-output (MIMO) broadcast channels (BC), assisted by simultaneously transmitting and reflecting (STA…
Rate Analysis and Optimization of LoS Beyond Diagonal RIS-assisted MIMO Systems
Ignacio Santamaria, Jesus Gutierrez, Mohammad Soleymani +1
In this letter, we derive an expression for the achievable rate in a multiple-input multiple-output (MIMO) system assisted by a beyond-diagonal reconfigurable intelligent surface (…
Interference Minimization in Beyond-Diagonal RIS-assisted MIMO Interference Channels
Ignacio Santamaria, Mohammad Soleymani, Eduard Jorswieck +1
This paper proposes a two-stage approach for passive and active beamforming in multiple-input multiple-output (MIMO) interference channels (ICs) assisted by a beyond-diagonal recon…