Constantinos B. Papadias

Constantinos B. Papadias
ALBA Graduate Business School

PhD

About

287
Publications
26,269
Reads
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7,526
Citations
Citations since 2017
78 Research Items
1712 Citations
2017201820192020202120222023050100150200250300
2017201820192020202120222023050100150200250300
2017201820192020202120222023050100150200250300
2017201820192020202120222023050100150200250300
Additional affiliations
October 2015 - present
Aalborg University
Position
  • Professor (Associate)
February 2006 - present
Athens Information Technology
Position
  • Head of Faculty
November 1997 - January 2006
Alcatel Lucent
Position
  • Tech. Manager

Publications

Publications (287)
Preprint
Full-text available
Aiming at overcoming practical issues of successive interference cancellation (SIC), this paper proposes a dual-polarized rate-splitting multiple access (RSMA) technique for a downlink massive multiple-input multiple-output (MIMO) network. By modeling the effects of polarization interference, an in-depth theoretical analysis is carried out, in whic...
Preprint
Full-text available
Unmanned Aerial Vehicle (UAV) swarms are often required in off-grid scenarios, such as disaster-struck, war-torn or rural areas, where the UAVs have no access to the power grid and instead rely on renewable energy. Considering a main battery fed from two renewable sources, wind and solar, we scale such a system based on the financial budget, enviro...
Preprint
Full-text available
The polarization domain provides an extra degree of freedom (DoF) for improving the performance of multiple-input multiple-output (MIMO) systems. This paper takes advantage of this additional DoF to alleviate practical issues of successive interference cancellation (SIC) in rate-splitting multiple access (RSMA) schemes. Specifically, we propose thr...
Article
Full-text available
The classification of biological neuron types and networks poses challenges to the full understanding of the human brain’s organisation and functioning. In this paper, we develop a novel objective classification model of biological neuronal morphology and electrical types and their networks, based on the attributes of neuronal communication using s...
Article
Full-text available
This letter proposes a novel dual-polarized rate-splitting multiple access (RSMA) technique for massive multiple-input multiple-output (MIMO) networks. The proposed strategy transmits common and private symbols in parallel through dynamic polarization multiplexing, and it does not require successive interference cancellation (SIC) in the reception....
Preprint
Full-text available
In this work, we propose a framework for energy-efficient trajectory design of an unmanned aerial vehicle (UAV)-based portable access point (PAP) deployed to serve a set of ground nodes (GNs). In addition to the PAP and GNs, the system consists of a set of intelligent reflecting surfaces (IRSs) mounted on man-made structures to increase the number...
Preprint
Full-text available
In this work, we study the trade-off between the reliability and the investment cost of an unmanned aerial system (UAS) consisting of a set of unmanned aerial vehicles (UAVs) carrying radio access nodes, called portable access points (PAPs)), deployed to serve a set of ground nodes (GNs). Using the proposed algorithm, a given geographical region is...
Preprint
p>In this work, we optimize the 3D trajectory of an unmanned aerial vehicle (UAV)-based portable access point (PAP) that provides wireless services to a set of ground nodes (GNs). Moreover, as per the Peukert effect, we consider pragmatic non-linear battery discharge for UAV’s battery. Thus, we formulate the problem in a novel manner that represent...
Preprint
p>In this work, we optimize the 3D trajectory of an unmanned aerial vehicle (UAV)-based portable access point (PAP) that provides wireless services to a set of ground nodes (GNs). Moreover, as per the Peukert effect, we consider pragmatic non-linear battery discharge for UAV’s battery. Thus, we formulate the problem in a novel manner that represent...
Preprint
Full-text available
In this work, we optimize the 3D trajectory of an unmanned aerial vehicle (UAV)-based portable access point (PAP) that provides wireless services to a set of ground nodes (GNs). Moreover, as per the Peukert effect, we consider pragmatic non-linear battery discharge for the battery of the UAV. Thus, we formulate the problem in a novel manner that re...
Article
Rate-splitting multiple access (RSMA) has recently appeared as a powerful technique for improving the downlink performance of multiple-input multiple-output systems. By flexibly managing interference, RSMA can deliver high spectral and energy efficiency, as well as robustness to imperfect channel state information. In another development, an intell...
Preprint
Full-text available
This work investigates the performance of intelligent reflective surfaces (IRSs) assisted uplink non-orthogonal multiple access (NOMA) in energy-constrained networks. Specifically, we formulate and solve two optimization problems, one for minimizing the users' sum transmit power and another for maximizing the energy efficiency (EE) of the system. T...
Preprint
Full-text available
Rate-splitting multiple access (RSMA) has recently appeared as a powerful technique for improving the downlink performance of multiple-input multiple-output (MIMO) systems. By flexibly managing interference, RSMA can deliver high spectral and energy efficiency, as well as robustness to imperfect channel state information (CSI). In another developme...
Article
Full-text available
In this work, we optimize the 3D trajectory of an unmanned aerial vehicle (UAV)-based portable access point (PAP) that provides wireless services to a set of ground nodes (GNs). Moreover, as per the Peukert effect, we consider pragmatic non-linear battery discharge for UAV’s battery. Thus, we formulate the problem in a novel manner that represents...
Article
In this work, we propose a framework for energy efficient trajectory design of an unmanned aerial vehicle (UAV)-based portable access point (PAP) deployed to serve a set of ground nodes (GNs). In addition to the PAP and GNs, the system consists of a set of intelligent reflecting surfaces (IRSs) mounted on man-made structures to increase the number...
Article
The polarization domain provides an extra degree of freedom (DoF) for improving the performance of multiple-input multiple-output (MIMO) systems. This paper takes advantage of this additional DoF to alleviate practical issues of successive interference cancellation (SIC) in rate-splitting multiple access (RSMA) schemes. Specifically, we propose thr...
Article
Unmanned Aerial Vehicle (UAV) swarms are often required in off-grid scenarios, such as disaster-struck, war-torn or rural areas, where the UAVs have no access to the power grid and instead rely on renewable energy. Considering a main battery fed from two renewable sources, wind and solar, we scale such a system based on the financial budget, enviro...
Article
This work proposes a methodology for the energy-and cost-efficient 3-D deployment of an unmanned aerial vehicle (UAV)-based aerial access point (AAP), that exchanges a given amount of independent data with a set of ground user equipment (UE). Considering a fly-hover-communicate transmission scheme, the most energy-efficient 3-D hovering points (HPs...
Preprint
This work proposes a methodology for the energy-and cost-efficient 3-D deployment of an unmanned aerial vehicle (UAV)-based aerial access point (AAP), that exchanges a given amount of independent data with a set of ground user equipment (UE). Considering a fly-hover-communicate transmission scheme, the most energy-efficient 3-D hovering points (HPs...
Preprint
This work proposes a methodology for the energy-and cost-efficient 3-D deployment of an unmanned aerial vehicle (UAV)-based aerial access point (AAP), that exchanges a given amount of independent data with a set of ground user equipment (UE). Considering a fly-hover-communicate transmission scheme, the most energy-efficient 3-D hovering points (HPs...
Article
Full-text available
In this work, intelligent reflecting surfaces (IRSs) are optimized to manipulate signal polarization and improve the uplink performance of a dual-polarized multiple-input multiple-output (MIMO) non-orthogonal multiple access (NOMA) network. By multiplexing subsets of users in the polarization domain, we propose a strategy for reducing the interfere...
Preprint
Full-text available
In this paper, the appealing features of a dual-polarized intelligent reflecting surface (IRS) are exploited to improve the performance of dual-polarized massive multiple-input multiple-output (MIMO) with non-orthogonal multiple access (NOMA) under imperfect successive interference cancellation (SIC). By considering the downlink of a multi-cluster...
Article
A dual-polarized intelligent reflecting surface (IRS) can contribute to a better multiplexing of interfering wireless users. In this paper, we use this feature to improve the performance of dual-polarized massive multiple-input multiple-output (MIMO) with non-orthogonal multiple access (NOMA) under imperfect successive interference cancellation (SI...
Preprint
div>In this work, we propose a methodology for the energy-efficient placement of an unmanned aerial system (UAS) deployed to collect data from a set of ground user equipments (UEs). The data-communication between the UEs and the UxNB, a radio access node carried by an unmanned aerial vehicle (UAV), of the UAS follows a non-orthogonal multiple-acces...
Preprint
div>In this work, we propose a methodology for the energy-efficient placement of an unmanned aerial system (UAS) deployed to collect data from a set of ground user equipments (UEs). The data-communication between the UEs and the UxNB, a radio access node carried by an unmanned aerial vehicle (UAV), of the UAS follows a non-orthogonal multiple-acces...
Preprint
Full-text available
In this paper, we propose an energy-efficient optimal altitude for an aerial access point (AAP), which acts as a flying base station to serve a set of ground user equipment (UE). Since the ratio of total energy consumed by the aerial vehicle to the communication energy is very large, we include the aerial vehicle's energy consumption in the problem...
Preprint
Full-text available
A dual-polarized intelligent reflecting surface (IRS) can contribute to a better multiplexing of interfering wireless users. In this paper, we use this feature to improve the performance of dual-polarized massive multiple-input multiple-output (MIMO) with non-orthogonal multiple access (NOMA) under imperfect successive interference cancellation (SI...
Preprint
Full-text available
In this letter, we propose an energy-efficient 3- dimensional placement of multiple aerial access points (AAPs), in the desired area, acting as flying base stations for uplink communication from a set of ground user equipment (UE). The globally optimal energy-efficient vertical position of AAPs is derived analytically by considering the inter-cell...
Preprint
In this letter, we propose an energy-efficient 3- dimensional placement of multiple aerial access points (AAPs), in the desired area, acting as flying base stations for uplink communication from a set of ground user equipment (UE). The globally optimal energy-efficient vertical position of AAPs is derived analytically by considering the inter-cell...
Preprint
In this paper, we propose an energy-efficient optimal altitude for an aerial access point (AAP), which acts as a flying base station to serve a set of ground user equipment (UE). Since the ratio of total energy consumed by the aerial vehicle to the communication energy is very large, we include the aerial vehicle’s energy consumption in the problem...
Preprint
In this paper, we propose an energy-efficient optimal altitude for an aerial access point (AAP), which acts as a flying base station to serve a set of ground user equipment (UE). Since the ratio of total energy consumed by the aerial vehicle to the communication energy is very large, we include the aerial vehicle’s energy consumption in the problem...
Article
Full-text available
Massive multiple-input multiple-output (MIMO) and non-orthogonal multiple access (NOMA) are two key techniques for enabling massive connectivity in future wireless networks. A massive MIMO-NOMA system can deliver remarkable spectral improvements and low communication latency. Nevertheless, the uncontrollable stochastic behavior of the wireless chan...
Preprint
Full-text available
Massive multiple-input multiple-output (MIMO) and non-orthogonal multiple access (NOMA) are two key techniques for enabling massive connectivity in future wireless networks. A massive MIMO-NOMA system can deliver remarkable spectral improvements and low communication latency. Nevertheless, the uncontrollable stochastic behavior of the wireless chan...
Article
Parasitic antenna arrays (PAAs) with a single radio frequency (RF) chain have been used to enable new trends and paradigms for multi-antenna transmission [1]. Significant reduction in hardware complexity, size and cost can be obtained with single-RF PAAs, as only the active element (AE) is directly connected to the voltage through an RF connection....
Article
In this letter, we propose an energy-efficient 3-dimensional placement of multiple aerial access points (AAPs), in the desired area, acting as flying base stations for uplink communication from a set of ground user equipment (UE). The globally optimal energy-efficient vertical position of AAPs is derived analytically by considering the inter-cell i...
Article
Full-text available
Spectrum sharing has been recognized as a key component for 5G and beyond wireless networks. Recent trials have revealed the business value of spectrum sharing via the licensed shared access model, wherein both the incumbent and the licensee operators are protected from harmful interference by sharing the available spectrum using long-term spectrum...
Article
Radio-frequency wireless energy transfer (RF-WET) is emerging as a potential green enabler for massive Internet of Things (IoT). Herein, we analyze channel state information (CSI)-free multiantenna strategies for powering wirelessly a large set of single-antenna IoT devices. The CSI-free schemes are AA-SS (AA-IS), where all antennas transmit the sa...
Article
This paper addresses multi-user multi-cluster massive multiple-input-multiple-output (MIMO) systems with non-orthogonal multiple access (NOMA). Assuming the downlink mode, and taking into consideration the impact of imperfect successive interference cancellation (SIC), an in-depth analytical analysis is carried out, in which closed-form expressions...
Chapter
This chapter focuses on the role of antenna arrays in spectrum sharing, with emphasis on the spectrum sensing and shared spectrum access areas, for which specific representative examples are provided. It summarizes the key attributes of antenna arrays, namely signal power gain, interference nulling ability, diversity gain, and spatial multiplexing...
Preprint
Full-text available
Classification of biological neuron types and networks poses challenges to the full understanding of the brain's organisation and functioning. In this paper, we develop a novel objective classification model of biological neuronal types and networks based on the communication metrics of neurons. This presents advantages against the existing approac...
Article
Full-text available
5G cellular networks will heavily rely on the use of techniques that increase the spectral efficiency (SE) to meet the stringent capacity requirements of the envisioned services. To this end, the use of coordinated multi-point (CoMP) as an enabler of underlay spectrum sharing promises substantial SE gains. In this work, we propose novel low-complex...
Preprint
Full-text available
Wireless Energy Transfer (WET) is emerging as a potential green enabler for massive Internet of Things (IoT). Herein, we analyze Channel State Information (CSI)-free multi-antenna strategies for powering wirelessly a large set of single-antenna IoT devices. The CSI-free schemes are AA-SS (AA-IS), where all antennas transmit the same (independent) s...
Article
Full-text available
The high cost and energy consumption of fully digital massive multiple-input multiple-output (MIMO) systems has led to hybrid designs with fewer radio frequency (RF) chains than antennas. In this letter, we propose an efficient hybrid processing algorithm for point-to-point (P2P) massive MIMO systems that operate in either rich or poor scattering e...
Article
In this paper, we propose a novel successive sub-array activation (SSAA) diversity scheme for a massive multiple-input multiple-output (MIMO) system in combination with non-orthogonal multiple access (NOMA). Considering a single-cell multi-cluster downlink scenario, where the base station (BS) sends redundant symbols through multiple transmit sub-a...
Chapter
Multi-Active Multi-Passive (MAMP) antenna arrays with reduced number of active elements are studied, for matching the patterns of all-active uniform linear arrays. Based on previous work on MAMP antenna arrays, we present a novel configuration, namely a circular one. By jointly calculating the PEs’ loads and baseband weights of the proposed MAMP ar...
Article
The papers in this special section focus on hybrid analog-digital signal processing for hardware efficient large scale antenna arrays. Hybrid analog-digital (HAD) processing provides a key technology for the coming generations of wireless networks, as a means of obtaining hardware-efficient transceivers. The principle behind HAD is that the transce...
Preprint
Full-text available
In this paper we consider Multi-Active Multi-Passive (MAMP) antenna arrays with a reduced number of active elements (AEs) for emulating the patterns of all-active uniform linear arrays (ULAs). Moreover, we present a novel alternating optimization stochastic scheme for the joint determination of the passive elements' (PEs) loads and baseband weights...
Article
Full-text available
The papers in this special section focus on hybrid analog-digital signal processing for hardware efficient large scale antenna arrays. Hybrid analog-digital (HAD) processing provides a key technology for the coming generations of wireless networks, as a means of obtaining hardware-efficient transceivers. The principle behind HAD is that the transce...
Article
Spectrum sharing has been proposed as a promising way to increase the efficiency of spectrum usage by allowing Incumbent Operators (IOs) to share their allocated radio resources with Licensee Operators (LOs), under a set of agreed rules. The goal is to maximize a common utility, such as the sum rate throughput, while maintaining the level of servic...
Article
Electronically steerable parasitic array radiator (ESPAR) technology enables the implementation of antenna arrays of a number of elements with a single radio frequency (RF) source. Two approaches to achieve stable transmission using an ESPAR antenna (EA) are to increase the self-resistance of an EA or to transmit signals closely approximating the a...
Article
Compact parasitic arrays in the form of electronically steerable parasitic antenna radiators (ESPARs) have emerged as a new antenna structure that achieves multipleinput- multiple-output (MIMO) transmission with a single RF chain. In this paper, we study the application of precoding on practical ESPARs, where the antennas are equipped with load imp...
Article
Single-user multiple-input / multiple-output (SU-MIMO) communication systems have been successfully used over the years and have provided a significant increase on a wireless link's capacity by enabling the transmission of multiple data streams. Assuming channel knowledge at the transmitter, the maximization of the mutual information of a MIMO link...
Article
Full-text available
As network deployments become denser, interference arises as a dominant performance degradation factor. To confront with this trend, Long Term Evolution (LTE) incorporated features aiming at enabling cooperation among different base stations, a technique termed as Coordinated Multi Point (CoMP). Recent field trial results and theoretical studies of...