Active ris systems reduce worst user outage probability
Worst-User Outage Probability Minimization in Active RIS-Aided Systems
Information Theory
Summary
This paper looks at how to make wireless connections more reliable for the user with the worst connection in a system that uses active reconfigurable intelligent surfaces (RIS). The authors tackled the problem of unpredictable signal interruptions by creating a smarter way to adjust the signal beams and the RIS reflections. They developed a method that learns from past signal data to reduce the chances of bad connection drops. Their simulations show that this approach improves the reliability of active RIS systems.
What this means in practice
- •For telecommunications engineers: Design wireless access points that better handle the worst user’s connection reliability using active RIS and data-driven optimization.
- •For wireless network planners: Optimize reflection surfaces and beamforming in network layouts to lower outage events for users in challenging signal conditions.
Authors
Donghwan Shin, Hyeongtaek Lee, Junil Choi
Abstract
In this paper, a worst-user outage probability minimization problem in active reconfigurable intelligent surface (RIS)-aided systems is addressed. Since the resulting problem involves a discontinuous objective function over an unknown channel distribution, a sequence of reformulations is applied by integrating a probability-simplex user weighting, a softplus surrogate for differentiability, and entropic tail-risk aggregation for rare but severe outage events. Based on the reformulated problem, a data-driven stochastic optimization technique that relies on historical channel samples is adopted to jointly optimize the beamformer and reflection coefficients with projected adaptive moment estimation. Simulation results show advantages of the proposed technique for reliability-oriented active RIS transmission design.