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Browsing by Author "Papazafeiropoulos, Anastasios"
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Coverage Probability of STAR-RIS assisted Massive MIMO systems with Correlation and Phase Errors
Papazafeiropoulos, Anastasios; Abdullah, Zaid; Kourtessis, Pandelis; Kisseleff, Steven; Krikidis, Ioannis (2022-06-01)In this letter, we investigate a simultaneous transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) assisting a massive multiple-input multiple-output (mMIMO) system. In particular, we derive a closed-form ... -
Deep Channel Learning For Large Intelligent Surfaces Aided mm-Wave Massive MIMO Systems
Elbir, Ahmet M.; Papazafeiropoulos, Anastasios; Kourtessis, Pandelis; Chatzinotas, Symeon; Senior, John (2020-09)This letter presents the first work introducing a deep learning (DL) framework for channel estimation in large intelligent surface (LIS) assisted massive MIMO (multiple-input multiple-output) systems. A twin convolutional ... -
Hybrid Precoding for Multiuser Millimeter Wave Massive MIMO Systems : A Deep Learning Approach
Elbir, Ahmet M.; Papazafeiropoulos, Anastasios (2019-11-04)In multi-user millimeter wave (mmWave) multiple-input-multiple-output (MIMO) systems, hybrid precoding is a crucial task to lower the complexity and cost while achieving a sufficient sum-rate. Previous works on hybrid ... -
Impact of Phase-Noise and Spatial Correlation on Double-RIS-Assisted Multiuser MISO Networks
Abdullah, Zaid; Papazafeiropoulos, Anastasios; Kisseleff, Steven; Chatzinotas, Symeon; Ottersten, Bjorn (2022-05-17)We study the performance of a phase-noise impaired double reconfigurable intelligent surface (RIS)-aided multiuser (MU) multiple-input single-output (MISO) system under spatial correlation at both RISs and base-station ... -
Impact of Residual Additive Transceiver Hardware Impairments on Rayleigh-Product MIMO Channels with Linear Receivers : Exact and Asymptotic Analyses
Papazafeiropoulos, Anastasios; Sharma, Shree Krishna; Ratnarajah, Tharmalingam; Chatzinotas, Symeon (2018-01-31)Despite the importance of Rayleigh-product multiple-input multiple-output channels and their experimental validations, there is no work investigating their performance in the presence of residual additive transceiver ... -
Joint Spatial Division and Multiplexing for FDD in Intelligent Reflecting Surface-assisted Massive MIMO Systems
Papazafeiropoulos, Anastasios; Kourtessis, Pandelis; Ntontin, Konstantinos; Chatzinotas, Symeon (2022-06-30)Intelligent reflecting surface (IRS) is a promising technology to deliver the higher spectral and energy requirements in fifth-generation (5G) and beyond wireless networks while shaping the propagation environment. Such a ... -
Modeling and Performance of Uplink Cache-Enabled Massive MIMO Heterogeneous Networks
Papazafeiropoulos, Anastasios; Ratnarajah, Tharmalingham (2018-12-01)A significant burden on wireless networks is brought by the uploading of user-generated contents to the Internet by means of applications such as social media. To cope with this mobile data tsunami, we develop a novel ... -
Nuts and Bolts of a Realistic Stochastic Geometric Analysis of mmWave HetNets: Hardware Impairments and Channel Aging
Papazafeiropoulos, Anastasios; Ratnarajah, Tharmalingam; Kourtessis, Pandelis; Chatzinotas, Symeon (2019-03-28)Motivated by heterogeneous network (HetNet) design in improving coverage and by millimeter-wave (mmWave) transmission offering an abundance of extra spectrum, we present a general analytical framework shedding light on the ... -
Optimal energy efficiency in cell-free massive MIMO systems: A stochastic geometry approach
Papazafeiropoulos, Anastasios; Ngo, Hien Quoc; Kourtessis, Pandelis; Chatzinotas, Symeon; Senior, John M. (Institute of Electrical and Electronics Engineers (IEEE), 2020-10-08)The increasing demand for green wireless communications and the benefits of the promising cell-free (CF) massive multiple-input-multiple-output (mMIMO) systems towards their optimal energy efficiency (EE) are the focal ... -
Performance Analysis of Cell-Free Massive MIMO Systems: A Stochastic Geometry Approach
Papazafeiropoulos, Anastasios; Kourtessis, Pandelis; Renzo, Marco Di; Chatzinotas, Symeon; Senior, John (2020-04)Cell-free (CF) massive multiple-input-multiple-output (MIMO) has emerged as an alternative deployment for conventional cellular massive MIMO networks. As revealed by its name, this topology considers no cells, while a large ... -
Rate-Splitting Robustness in Multi-Pair Massive MIMO Relay Systems
Papazafeiropoulos, Anastasios; Ratnarajah, Tharmalingam (2018-08-01)Relay systems improve both coverage and system capacity. Toward this direction, a full-duplex (FD) technology, being able to boost the spectral efficiency by transmitting and receiving simultaneously on the same frequency ... -
SDN-enabled MIMO Heterogeneous Cooperative Networks with Flexible Cell Association
Papazafeiropoulos, Anastasios; Kourtessis, Pandelis; Renzo, Marco Di; Senior, John M.; Chatzinotas, Symeon (2019-04-01)Small-cell densification is a strategy enabling the offloading of users from macro base stations (MBSs), in order to alleviate their load and increase the coverage, especially, for cell-edge users. In parallel, as the ... -
Toward a Realistic Assessment of Multiple Antenna HCNs: Residual Additive Transceiver Hardware Impairments and Channel Aging
Papazafeiropoulos, Anastasios; Ratnarajah, Tharmalingam (2017-10-01)Given the critical dependence of broadcast channels by the accuracy of channel state information at the transmitter (CSIT), we develop a general downlink model with zero-forcing precoding, applied in realistic heterogeneous ... -
Wireless Energy Harvesting For Autonomous Reconfigurable Intelligent Surfaces
Ntontin, Konstantinos; Boulogeorgos, Alexandros Apostolos A.; Bjornson, Emil; Martins, Wallace Alves; Kisseleff, Steven; Abadal, Sergi; Alarcon, Eduard; Papazafeiropoulos, Anastasios; Lazarakis, Fotis; Chatzinotas, Symeon (2023-03-30)In the current contribution, we examine the feasibility of fully-energy-autonomous operation of reconfigurable intelligent surfaces (RIS) through wireless energy harvesting (EH) from incident information signals. Towards ...