10 papers · 1 filter
The manifold of unitary and symmetric matrices: characterization, Riemannian optimization and application to BD-RIS design
Ignacio Santamaria, Carlos Beltrán, Eduard Jorswieck +2
This paper proposes and analyzes Riemannian optimization algorithms on the manifold of unitary and symmetric matrices, denoted , which naturally models the scattering…
Optimal symmetric low-rank BD-RIS configuration maximizing the determinant of a MIMO link
Ignacio Santamaria, Mohammad Soleymani, Jesus Gutierrez +1
Beyond-diagonal reconfigurable intelligent surfaces (BD-RISs) significantly improve wireless performance by allowing tunable interconnections among elements, but their design in mu…
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…
URLLC Networks enabled by STAR-RIS, Rate Splitting, and Multiple Antennas
Eduard Jorswieck, Mohammad Soleymani, Ignacio Santamaria +1
The challenges in dense ultra-reliable low-latency communication networks to deliver the required service to multiple devices are addressed by three main technologies: multiple ant…
Rate Splitting Multiple Access for RIS-aided URLLC MIMO Broadcast Channels
Mohammad Soleymani, Ignacio Santamaria, Eduard Jorswieck +3
The performance of modern wireless communication systems is typically limited by interference. The impact of interference can be even more severe in ultra-reliable and low-latency…
Rate Region of RIS-Aided URLLC Broadcast Channels: Diagonal versus Beyond Diagonal Globally Passive RIS
Mohammad Soleymani, Alessio Zappone, Eduard Jorswieck +2
We analyze the finite-block-length rate region of wireless systems aided by reconfigurable intelligent surfaces (RISs), employing treating interference as noise. We consider three…
Energy Efficiency Comparison of RIS Architectures in MISO Broadcast Channels
Mohammad Soleymani, Ignacio Santamaria, Eduard Jorswieck +2
In this paper, we develop energy-efficient schemes for multi-user multiple-input single-output (MISO) broadcast channels (BCs), assisted by reconfigurable intelligent surfaces (RIS…