203 research outputs found
A Comprehensive Survey on Moving Networks
The unprecedented increase in the demand for mobile data, fuelled by new
emerging applications such as HD video streaming and heightened online
activities has caused massive strain on the existing cellular networks. As a
solution, the 5G technology has been introduced to improve network performance
through various innovative features such as mmWave spectrum and HetNets. In
essence, HetNets include several small cells underlaid within macro-cell to
serve densely populated regions. Recently, a mobile layer of HetNet has been
under consideration by the researchers and is often referred to as moving
networks. Moving networks comprise of mobile cells that are primarily
introduced to improve QoS for commuting users inside public transport because
the QoS is deteriorated due to vehicular penetration losses. Furthermore, the
users inside fast moving public transport also exert excessive load on the core
network due to large group handovers. To this end, mobile cells will play a
crucial role in reducing overall handover count and will help in alleviating
these problems by decoupling in-vehicle users from the core network.
To date, remarkable research results have been achieved by the research
community in addressing challenges linked to moving networks. However, to the
best of our knowledge, a discussion on moving networks in a holistic way is
missing in the current literature. To fill the gap, in this paper, we
comprehensively survey moving networks. We cover the technological aspects and
their applications in the futuristic applications. We also discuss the
use-cases and value additions that moving networks may bring to future cellular
architecture and identify the challenges associated with them. Based on the
identified challenges we discuss the future research directions.Comment: This survey has been submitted to IEEE Communications Surveys &
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Performance analysis of massive multiple input multiple output for high speed railway
This paper analytically reviews the performance of massive multiple input multiple output (MIMO) system for communication in highly mobility scenarios like high speed Railways. As popularity of high speed train increasing day by day, high data rate wireless communication system for high speed train is extremely required. 5G wireless communication systems must be designed to meet the requirement of high speed broadband services at speed of around 500 km/h, which is the expected speed achievable by HSR systems, at a data rate of 180 Mbps or higher. Significant challenges of high mobility communications are fast time-varying fading, channel estimation errors, doppler diversity, carrier frequency offset, inter carrier interference, high penetration loss and fast and frequent handovers. Therefore, crucial requirement to design high mobility communication channel models or systems prevails. Recently, massive MIMO techniques have been proposed to significantly improve the performance of wireless networks for upcoming 5G technology. Massive MIMO provide high throughput and high energy efficiency in wireless communication channel. In this paper, key findings, challenges and requirements to provide high speed wireless communication onboard the high speed train is pointed out after thorough literature review. In last, future research scope to bridge the research gap by designing efficient channel model by using massive MIMO and other optimization method is mentioned
QoS-aware User Association and Transmission Scheduling for Millimeter-Wave Train-ground Communications
With the development of wireless communication, people have put forward
higher requirements for train-ground communications in the high-speed railway
(HSR) scenarios. With the help of mobile relays (MRs) installed on the roof of
the train, the application of Millimeter-Wave (mm-wave) communication which has
rich spectrum resources to the train-ground communication system can realize
high data rate, so as to meet users' increasing demand for broad-band
multimedia access. Also, full-duplex (FD) technology can theoretically double
the spectral efficiency. In this paper, we formulate the user association and
transmission scheduling problem in the mm-wave train-ground communication
system with MR operating in the FD mode as a nonlinear programming problem. In
order to maximize the system throughput and the number of users meeting quality
of service (QoS) requirements, we propose an algorithm based on coalition game
to solve the challenging NP-hard problem, and also prove the convergence and
Nash-stable structure of the proposed algorithm. Extensive simulation results
demonstrate that the proposed coalition game based algorithm can effectively
improve the system throughput and meet the QoS requirements of as many users as
possible, so that the communication system has a certain QoS awareness.Comment: 14 page
Towards the Internet of Smart Trains: A Review on Industrial IoT-Connected Railways
[Abstract] Nowadays, the railway industry is in a position where it is able to exploit the opportunities created by the IIoT (Industrial Internet of Things) and enabling communication technologies under the paradigm of Internet of Trains. This review details the evolution of communication technologies since the deployment of GSM-R, describing the main alternatives and how railway requirements, specifications and recommendations have evolved over time. The advantages of the latest generation of broadband communication systems (e.g., LTE, 5G, IEEE 802.11ad) and the emergence of Wireless Sensor Networks (WSNs) for the railway environment are also explained together with the strategic roadmap to ensure a smooth migration from GSM-R. Furthermore, this survey focuses on providing a holistic approach, identifying scenarios and architectures where railways could leverage better commercial IIoT capabilities. After reviewing the main industrial developments, short and medium-term IIoT-enabled services for smart railways are evaluated. Then, it is analyzed the latest research on predictive maintenance, smart infrastructure, advanced monitoring of assets, video surveillance systems, railway operations, Passenger and Freight Information Systems (PIS/FIS), train control systems, safety assurance, signaling systems, cyber security and energy efficiency. Overall, it can be stated that the aim of this article is to provide a detailed examination of the state-of-the-art of different technologies and services that will revolutionize the railway industry and will allow for confronting today challenges.Galicia. Consellería de Cultura, Educación e Ordenación Universitaria; ED431C 2016-045Galicia. Consellería de Cultura, Educación e Ordenación Universitaria; ED341D R2016/012Galicia. Consellería de Cultura, Educación e Ordenación Universitaria; ED431G/01Agencia Estatal de Investigación (España); TEC2013-47141-C4-1-RAgencia Estatal de Investigación (España); TEC2015-69648-REDCAgencia Estatal de Investigación (España); TEC2016-75067-C4-1-
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