2,187 research outputs found
Architectures and Key Technical Challenges for 5G Systems Incorporating Satellites
Satellite Communication systems are a promising solution to extend and
complement terrestrial networks in unserved or under-served areas. This aspect
is reflected by recent commercial and standardisation endeavours. In
particular, 3GPP recently initiated a Study Item for New Radio-based, i.e., 5G,
Non-Terrestrial Networks aimed at deploying satellite systems either as a
stand-alone solution or as an integration to terrestrial networks in mobile
broadband and machine-type communication scenarios. However, typical satellite
channel impairments, as large path losses, delays, and Doppler shifts, pose
severe challenges to the realisation of a satellite-based NR network. In this
paper, based on the architecture options currently being discussed in the
standardisation fora, we discuss and assess the impact of the satellite channel
characteristics on the physical and Medium Access Control layers, both in terms
of transmitted waveforms and procedures for enhanced Mobile BroadBand (eMBB)
and NarrowBand-Internet of Things (NB-IoT) applications. The proposed analysis
shows that the main technical challenges are related to the PHY/MAC procedures,
in particular Random Access (RA), Timing Advance (TA), and Hybrid Automatic
Repeat reQuest (HARQ) and, depending on the considered service and
architecture, different solutions are proposed.Comment: Submitted to Transactions on Vehicular Technologies, April 201
Technologies and solutions for location-based services in smart cities: past, present, and future
Location-based services (LBS) in smart cities have drastically altered the way cities operate, giving a new dimension to the life of citizens. LBS rely on location of a device, where proximity estimation remains at its core. The applications of LBS range from social networking and marketing to vehicle-toeverything communications. In many of these applications, there is an increasing need and trend to learn the physical distance between nearby devices. This paper elaborates upon the current needs of proximity estimation in LBS and compares them against the available Localization and Proximity (LP) finding technologies (LP technologies in short). These technologies are compared for their accuracies and performance based on various different parameters, including latency, energy consumption, security, complexity, and throughput. Hereafter, a classification of these technologies, based on various different smart city applications, is presented. Finally, we discuss some emerging LP technologies that enable proximity estimation in LBS and present some future research areas
Positioning for the Internet of Things: A 3GPP Perspective
Many use cases in the Internet of Things (IoT) will require or benefit from
location information, making positioning a vital dimension of the IoT. The 3rd
Generation Partnership Project (3GPP) has dedicated a significant effort during
its Release 14 to enhance positioning support for its IoT technologies to
further improve the 3GPP-based IoT eco-system. In this article, we identify the
design challenges of positioning support in Long-Term Evolution Machine Type
Communication (LTE-M) and Narrowband IoT (NB-IoT), and overview the 3GPP's work
in enhancing the positioning support for LTE-M and NB-IoT. We focus on Observed
Time Difference of Arrival (OTDOA), which is a downlink based positioning
method. We provide an overview of the OTDOA architecture and protocols,
summarize the designs of OTDOA positioning reference signals, and present
simulation results to illustrate the positioning performance.Comment: 8 pages; 7 figures; 1 table; submitted for publicatio
Internet of Things-aided Smart Grid: Technologies, Architectures, Applications, Prototypes, and Future Research Directions
Traditional power grids are being transformed into Smart Grids (SGs) to
address the issues in existing power system due to uni-directional information
flow, energy wastage, growing energy demand, reliability and security. SGs
offer bi-directional energy flow between service providers and consumers,
involving power generation, transmission, distribution and utilization systems.
SGs employ various devices for the monitoring, analysis and control of the
grid, deployed at power plants, distribution centers and in consumers' premises
in a very large number. Hence, an SG requires connectivity, automation and the
tracking of such devices. This is achieved with the help of Internet of Things
(IoT). IoT helps SG systems to support various network functions throughout the
generation, transmission, distribution and consumption of energy by
incorporating IoT devices (such as sensors, actuators and smart meters), as
well as by providing the connectivity, automation and tracking for such
devices. In this paper, we provide a comprehensive survey on IoT-aided SG
systems, which includes the existing architectures, applications and prototypes
of IoT-aided SG systems. This survey also highlights the open issues,
challenges and future research directions for IoT-aided SG systems
Massive Non-Orthogonal Multiple Access for Cellular IoT: Potentials and Limitations
The Internet of Things (IoT) promises ubiquitous connectivity of everything
everywhere, which represents the biggest technology trend in the years to come.
It is expected that by 2020 over 25 billion devices will be connected to
cellular networks; far beyond the number of devices in current wireless
networks. Machine-to-Machine (M2M) communications aims at providing the
communication infrastructure for enabling IoT by facilitating the billions of
multi-role devices to communicate with each other and with the underlying data
transport infrastructure without, or with little, human intervention. Providing
this infrastructure will require a dramatic shift from the current protocols
mostly designed for human-to-human (H2H) applications. This article reviews
recent 3GPP solutions for enabling massive cellular IoT and investigates the
random access strategies for M2M communications, which shows that cellular
networks must evolve to handle the new ways in which devices will connect and
communicate with the system. A massive non-orthogonal multiple access (NOMA)
technique is then presented as a promising solution to support a massive number
of IoT devices in cellular networks, where we also identify its practical
challenges and future research directions.Comment: To appear in IEEE Communications Magazin
Wireless Localization in Narrowband-IoT Networks
Internet of things (IoT) is an emerging technology, which connects devices to the internet and with the upcoming of 5G, even more devices will be connected. Narrowband-IoT (NB-IoT) is a promising cellular technology that supports the connection of IoT devices and their integration with the existing long-term evolution (LTE) networks. The Increase of location-based services that requires localization for IoT devices is growing with the increase in IoT devices and applications. This thesis considers the localization of IoT devices in the NB-IoT wireless network. Localization emulation is produced in which Software Defined Radio (SDR) used to implement Base stations (BS) and user equipment (UE). Channel emulator was used to emulate wireless channel conditions, and a personal computer (PC) to calculate the UE location. The distance from each BS to the UE is calculated using Time of arrival (TOA). Triangulation method used to estimate the UE's position from the different BSs distances to the UE. The accuracy of positioning is analysed with various simulation scenarios and the results compared with third generation partnership project (3GPP) Release 14 standards for NB-IoT. The positioning accuracy requirement of 50 m horizontal accuracy for localization in NB-IoT 3GPP standardized have been achieved, under Line of Sight (LOS) full triangulation scenarios 1 and 2
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