12 papers
Joint Access and Fronthaul Resource Allocation for Cell-Free Massive MIMO with Wireless Fronthaul
Ozan Alp Topal, Ãzlem TuÄfe Demir, Emil Björnson +1
Wireless fronthaul is a key enabler of flexible and scalable cell-free massive MIMO systems, but its limited capacity poses significant challenges for maintaining high and uniform…
Rethinking Energy Efficiency in Cell-Free Massive MIMO: The Role of Processing and Optical Fronthaul
Ozan Alp Topal, Ãzlem TuÄfe Demir, Cicek Cavdar
Cell-free massive MIMO promises uniformly high performance by combining densely distributed radio units, coherent transmission, and centralized processing. Unlike earlier radio gen…
Capacity Analysis of OFDM Systems with a Swarm of Network-Controlled Repeaters
DoÄa Evgür, Ozan Alp Topal, Ãzlem TuÄfe Demir
This paper investigates the uplink capacity of single-input single-output (SISO) systems assisted by a swarm of network-controlled repeaters (NCRs). We develop a rigorous wideband…
Energy Saving for Cell-Free Massive MIMO Networks: A Multi-Agent Deep Reinforcement Learning Approach
Qichen Wang, Keyu Li, Ozan Alp Topal +3
This paper focuses on energy savings in downlink operation of cell-free massive MIMO (CF mMIMO) networks under dynamic traffic conditions. We propose a multi-agent deep reinforceme…
Unlocking the Energy-Saving Potential in O-RAN Cell-Free Massive MIMO by Joint Orchestration of Radio, Wireless Fronthaul, and Cloud Resources
Ozan Alp Topal, Ãzlem TuÄfe Demir, Emil Björnson +1
Network virtualization and cloudification in Open Radio Access Networks (O-RAN) enable joint orchestration of the processing and fronthaul resources, which are essential for realiz…
NCR vs. Passive/Active RIS: How Much NCR Amplification is Required to Beat RIS?
Ãzlem TuÄfe Demir, Ozan Alp Topal, Cicek Cavdar +1
This paper investigates the fundamental tradeoff between reconfigurable intelligent surfaces (RISs) and network-controlled repeaters (NCRs) in terms of achievable signal-to-noise r…