7,502 research outputs found
Goodbye, ALOHA!
©2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The vision of the Internet of Things (IoT) to interconnect and Internet-connect everyday people, objects, and machines poses new challenges in the design of wireless communication networks. The design of medium access control (MAC) protocols has been traditionally an intense area of research due to their high impact on the overall performance of wireless communications. The majority of research activities in this field deal with different variations of protocols somehow based on ALOHA, either with or without listen before talk, i.e., carrier sensing multiple access. These protocols operate well under low traffic loads and low number of simultaneous devices. However, they suffer from congestion as the traffic load and the number of devices increase. For this reason, unless revisited, the MAC layer can become a bottleneck for the success of the IoT. In this paper, we provide an overview of the existing MAC solutions for the IoT, describing current limitations and envisioned challenges for the near future. Motivated by those, we identify a family of simple algorithms based on distributed queueing (DQ), which can operate for an infinite number of devices generating any traffic load and pattern. A description of the DQ mechanism is provided and most relevant existing studies of DQ applied in different scenarios are described in this paper. In addition, we provide a novel performance evaluation of DQ when applied for the IoT. Finally, a description of the very first demo of DQ for its use in the IoT is also included in this paper.Peer ReviewedPostprint (author's final draft
Evaluation, Modeling and Optimization of Coverage Enhancement Methods of NB-IoT
Narrowband Internet of Things (NB-IoT) is a new Low Power Wide Area Network
(LPWAN) technology released by 3GPP. The primary goals of NB-IoT are improved
coverage, massive capacity, low cost, and long battery life. In order to
improve coverage, NB-IoT has promising solutions, such as increasing
transmission repetitions, decreasing bandwidth, and adapting the Modulation and
Coding Scheme (MCS). In this paper, we present an implementation of coverage
enhancement features of NB-IoT in NS-3, an end-to-end network simulator. The
resource allocation and link adaptation in NS-3 are modified to comply with the
new features of NB-IoT. Using the developed simulation framework, the influence
of the new features on network reliability and latency is evaluated.
Furthermore, an optimal hybrid link adaptation strategy based on all three
features is proposed. To achieve this, we formulate an optimization problem
that has an objective function based on latency, and constraint based on the
Signal to Noise Ratio (SNR). Then, we propose several algorithms to minimize
latency and compare them with respect to accuracy and speed. The best hybrid
solution is chosen and implemented in the NS-3 simulator by which the latency
formulation is verified. The numerical results show that the proposed
optimization algorithm for hybrid link adaptation is eight times faster than
the exhaustive search approach and yields similar latency
Coverage and Deployment Analysis of Narrowband Internet of Things in the Wild
Narrowband Internet of Things (NB-IoT) is gaining momentum as a promising
technology for massive Machine Type Communication (mMTC). Given that its
deployment is rapidly progressing worldwide, measurement campaigns and
performance analyses are needed to better understand the system and move toward
its enhancement. With this aim, this paper presents a large scale measurement
campaign and empirical analysis of NB-IoT on operational networks, and
discloses valuable insights in terms of deployment strategies and radio
coverage performance. The reported results also serve as examples showing the
potential usage of the collected dataset, which we make open-source along with
a lightweight data visualization platform.Comment: Accepted for publication in IEEE Communications Magazine (Internet of
Things and Sensor Networks Series
SymbioCity: Smart Cities for Smarter Networks
The "Smart City" (SC) concept revolves around the idea of embodying
cutting-edge ICT solutions in the very fabric of future cities, in order to
offer new and better services to citizens while lowering the city management
costs, both in monetary, social, and environmental terms. In this framework,
communication technologies are perceived as subservient to the SC services,
providing the means to collect and process the data needed to make the services
function. In this paper, we propose a new vision in which technology and SC
services are designed to take advantage of each other in a symbiotic manner.
According to this new paradigm, which we call "SymbioCity", SC services can
indeed be exploited to improve the performance of the same communication
systems that provide them with data. Suggestive examples of this symbiotic
ecosystem are discussed in the paper. The dissertation is then substantiated in
a proof-of-concept case study, where we show how the traffic monitoring service
provided by the London Smart City initiative can be used to predict the density
of users in a certain zone and optimize the cellular service in that area.Comment: 14 pages, submitted for publication to ETT Transactions on Emerging
Telecommunications Technologie
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
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