11 citations · 17 across the 24 of their papers we have counts for
14 papers · 1 filter
Joint Access and Fronthaul Resource Allocation for Cell-Free Massive MIMO with Wireless Fronthaul
Ozan Alp Topal, Özlem Tuğfe 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, Özlem Tuğfe 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
Doğa Evgür, Ozan Alp Topal, Özlem Tuğfe 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…
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, Özlem Tuğfe 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?
Özlem Tuğfe 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…
Green One-Bit Quantized Precoding in Cell-Free Massive MIMO
Salih Gümüsbuğa, Ozan Alp Topal, Özlem Tuğfe Demir
Cell-free massive MIMO (multiple-input multiple-output) is expected to be one of the key technologies in sixth-generation (6G) and beyond wireless communications, offering enhanced…
Fair and Energy-Efficient Activation Control Mechanisms for Repeater-Assisted Massive MIMO
Ozan Alp Topal, Özlem Tuğfe Demir, Emil Björnson +1
Massive multiple-input multiple-output (mMIMO) has been the core of 5G due to its ability to improve spectral efficiency and spatial multiplexing significantly; however, cell-edge…
UAV-Based Cell-Free Massive MIMO: Joint Placement and Power Optimization under Fronthaul Capacity Limitations
Neetu R. R, Ozan Alp Topal, Özlem Tuğfe Demir +4
We consider a cell-free massive multiple-input multiple-output (mMIMO) network, where unmanned aerial vehicles (UAVs) equipped with multiple antennas serve as distributed UAV-acces…
Energy-Efficient Cell-Free Massive MIMO with Wireless Fronthaul
Ozan Alp Topal, Özlem Tuğfe Demir, Emil Björnson +1
Cell-free massive MIMO improves the fairness among the user equipments (UEs) in the network by distributing many cooperating access points (APs) around the region while connecting…
Communicate or Sense? AP Mode Selection in mmWave Cell-Free Massive MIMO-ISAC
Weixian Yan, Ozan Alp Topal, Zinat Behdad +2
Integrated sensing and communication (ISAC) is a promising technology for future mobile networks, enabling sensing applications to be performed by existing communication networks,…
Physical Layer Authentication for LEO Satellite Constellations
Ozan Alp Topal, Gunes Karabulut Kurt
Physical layer authentication (PLA) is the process of claiming identity of a node based on its physical layer characteristics such as channel fading or hardware imperfections. In t…
Securing the Inter-Spacecraft Links: Physical Layer Key Generation from Doppler Frequency Shift
Ozan Alp Topal, Gunes Karabulut Kurt, Halim Yanikomeroglu
In this work, we propose a secret key generation procedure specifically designed for the inter-spacecraft communication links. As a novel secrecy source, the spacecrafts utilize Do…
Securing the Inter-Spacecraft Links: Doppler Frequency Shift based Physical Layer Key Generation
Ozan Alp Topal, Gunes Karabulut Kurt, Halim Yanikomeroglu
We propose a novel physical layer secret key generation method for the inter-spacecraft communication links. By exploiting the Doppler frequency shifts of the reciprocal spacecraft…
Identification of Smart Jammers: Learning based Approaches Using Wavelet Representation
Ozan Alp Topal, Selen Gecgel, Ender Mete Eksioglu +1
Smart jammer nodes can disrupt communication between a transmitter and a receiver in a wireless network, and they leave traces that are undetectable to classical jammer identificat…