670 research outputs found
Review of the State-of-the-Art on Adaptive Protection for Microgrids based on Communications
The dominance of distributed energy resources in microgrids and the
associated weather dependency require flexible protection. They include devices
capable of adapting their protective settings as a reaction to (potential)
changes in system state. Communication technologies have a key role in this
system since the reactions of the adaptive devices shall be coordinated. This
coordination imposes strict requirements: communications must be available and
ultra-reliable with bounded latency in the order of milliseconds. This paper
reviews the state-of-the-art in the field and provides a thorough analysis of
the main related communication technologies and optimization techniques. We
also present our perspective on the future of communication deployments in
microgrids, indicating the viability of 5G wireless systems and
multi-connectivity to enable adaptive protection.Comment: Accepted to IEEE Trans. on Industrial Informatic
Positioning of multiple unmanned aerial vehicle base stations in future wireless network
Abstract. Unmanned aerial vehicle (UAV) base stations (BSs) can be a reliable and efficient alternative to full fill the coverage and capacity requirements when the backbone network fails to provide the requirements during temporary events and after disasters. In this thesis, we consider three-dimensional deployment of multiple UAV-BSs in a millimeter-Wave network. Initially, we defined a set of locations for a UAV-BS to be deployed inside a cell, then possible combinations of predefined locations for multiple UAV-BSs are determined and assumed that users have fixed locations. We developed a novel algorithm to find the feasible positions from the predefined locations of multiple UAVs subject to a signal-to-interference-plus-noise ratio (SINR) constraint of every associated user to guarantees the quality-of-service (QoS), UAV-BS’s limited hovering altitude constraint and restricted operating zone because of regulation policies. Further, we take into consideration the millimeter-wave transmission and multi-antenna techniques to generate directional beams to serve the users in a cell.
We cast the positioning problem as an ℓ₀ minimization problem. This is a combinatorial, NP-hard, and finding the optimum solution is not tractable by exhaustive search. Therefore, we focused on the sub-optimal algorithm to find a feasible solution. We approximate the ℓ₀ minimization problem as non-combinatorial ℓ₁-norm problem. The simulation results reveal that, with millimeter-wave transmission the positioning of the UAV-BS while satisfying the constrains is feasible. Further, the analysis shows that the proposed algorithm achieves a near-optimal location to deploy multiple UVABS simultaneously
Achieving Ultra-Low Latency in 5G Millimeter Wave Cellular Networks
The IMT 2020 requirements of 20 Gbps peak data rate and 1 millisecond latency
present significant engineering challenges for the design of 5G cellular
systems. Use of the millimeter wave (mmWave) bands above 10 GHz --- where vast
quantities of spectrum are available --- is a promising 5G candidate that may
be able to rise to the occasion.
However, while the mmWave bands can support massive peak data rates,
delivering these data rates on end-to-end service while maintaining reliability
and ultra-low latency performance will require rethinking all layers of the
protocol stack. This papers surveys some of the challenges and possible
solutions for delivering end-to-end, reliable, ultra-low latency services in
mmWave cellular systems in terms of the Medium Access Control (MAC) layer,
congestion control and core network architecture
Direct communication radio Iinterface for new radio multicasting and cooperative positioning
Cotutela: Universidad de defensa UNIVERSITA’ MEDITERRANEA DI REGGIO CALABRIARecently, the popularity of Millimeter Wave (mmWave) wireless networks has increased due to their capability to cope with the escalation of mobile data demands caused by the unprecedented proliferation of smart devices in the fifth-generation (5G). Extremely high frequency or mmWave band is a fundamental pillar in the provision of the expected gigabit data rates. Hence, according to both academic and industrial communities, mmWave technology, e.g., 5G New Radio (NR) and WiGig (60 GHz), is considered as one of the main components of 5G and beyond networks. Particularly, the 3rd Generation Partnership Project (3GPP) provides for the use of licensed mmWave sub-bands for the 5G mmWave cellular networks, whereas IEEE actively explores the unlicensed band at 60 GHz for the next-generation wireless local area networks. In this regard, mmWave has been envisaged as a new technology
layout for real-time heavy-traffic and wearable applications.
This very work is devoted to solving the problem of mmWave band communication system while enhancing its advantages through utilizing the direct communication radio interface for NR multicasting, cooperative positioning, and mission-critical applications. The main contributions presented in this work include: (i) a set of mathematical frameworks and simulation tools to characterize multicast traffic delivery in mmWave directional systems; (ii) sidelink
relaying concept exploitation to deal with the channel condition deterioration of dynamic multicast systems and to ensure mission-critical and ultra-reliable low-latency communications; (iii) cooperative positioning techniques analysis for enhancing cellular positioning accuracy for 5G+ emerging applications that require not only improved communication characteristics but also precise localization.
Our study indicates the need for additional mechanisms/research that can be utilized: (i) to further improve multicasting performance in 5G/6G systems; (ii) to investigate sideline aspects, including, but not limited to, standardization perspective and the next relay selection strategies; and (iii) to design cooperative positioning systems based on Device-to-Device (D2D) technology
Joint admission and association in vehicular networks
Abstract. To support vehicle to everything (V2X) communication which is an integral part of intelligent transportation systems (ITS), fifth generation (5G) communication systems will need to employ diverse range of technologies, which will ultimately lead to automated driving, improved traffic safety, improved traffic efficiency and infotainment.~V2X is considered as one of the most challenging applications of 5G, because it requires ultra reliable and low latency communication (URLLC) for safety critical applications and high data rates in many scenarios under mobility.
Vehicles which can communicate with a base station or road side unit (RSU) are primary vehicles, which can act as relays to secondary vehicles which are out of coverage from the network. Therefore vehicle to infrastructure (V2I) and vehicle to vehicle (V2V) communication are employed to provide coverage for out of coverage vehicles. In this study joint problem of admission control for primary vehicles and user association for secondary vehicles in a singe cell downlink vehicular network is considered. The objective is to maximize the number of admitted primary vehicles, while associating all secondary vehicles. We consider the underlying communication system is based on millimeter wave communication at 60 GHz and we cast the optimization problem as an ℓ₀ minimization problem. This problem is known to be combinatorial and NP-hard. Hence, we propose a sub optimal, two stage algorithm to solve it.
We compare the performance of proposed algorithm against the exhaustive search algorithm. From simulation results it can be observed, although the proposed algorithm is a sub optimal algorithm it gives optimal performance with improved efficiency. Hence, the proposed algorithm is able to determine the optimal association for vehicles which are out of coverage and optimal admission for vehicles which are in coverage
D2D-Based Grouped Random Access to Mitigate Mobile Access Congestion in 5G Sensor Networks
The Fifth Generation (5G) wireless service of sensor networks involves
significant challenges when dealing with the coordination of ever-increasing
number of devices accessing shared resources. This has drawn major interest
from the research community as many existing works focus on the radio access
network congestion control to efficiently manage resources in the context of
device-to-device (D2D) interaction in huge sensor networks. In this context,
this paper pioneers a study on the impact of D2D link reliability in
group-assisted random access protocols, by shedding the light on beneficial
performance and potential limitations of approaches of this kind against
tunable parameters such as group size, number of sensors and reliability of D2D
links. Additionally, we leverage on the association with a Geolocation Database
(GDB) capability to assist the grouping decisions by drawing parallels with
recent regulatory-driven initiatives around GDBs and arguing benefits of the
suggested proposal. Finally, the proposed method is approved to significantly
reduce the delay over random access channels, by means of an exhaustive
simulation campaign.Comment: First submission to IEEE Communications Magazine on Oct.28.2017.
Accepted on Aug.18.2019. This is the camera-ready versio
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