800 research outputs found
Car-to-Cloud Communication Traffic Analysis Based on the Common Vehicle Information Model
Although connectivity services have been introduced already today in many of
the most recent car models, the potential of vehicles serving as highly mobile
sensor platform in the Internet of Things (IoT) has not been sufficiently
exploited yet. The European AutoMat project has therefore defined an open
Common Vehicle Information Model (CVIM) in combination with a cross-industry,
cloud-based big data marketplace. Thereby, vehicle sensor data can be leveraged
for the design of entirely new services even beyond traffic-related
applications (such as localized weather forecasts). This paper focuses on the
prediction of the achievable data rate making use of an analytical model based
on empirical measurements. For an in-depth analysis, the CVIM has been
integrated in a vehicle traffic simulator to produce CVIM-complaint data
streams as a result of the individual behavior of each vehicle (speed, brake
activity, steering activity, etc.). In a next step, a simulation of vehicle
traffic in a realistically modeled, large-area street network has been used in
combination with a cellular Long Term Evolution (LTE) network to determine the
cumulated amount of data produced within each network cell. As a result, a new
car-to-cloud communication traffic model has been derived, which quantifies the
data rate of aggregated car-to-cloud data producible by vehicles depending on
the current traffic situations (free flow and traffic jam). The results provide
a reference for network planning and resource scheduling for car-to-cloud type
services in the context of smart cities
Heterogeneous LTE/ Wi-Fi architecture for intelligent transportation systems
Intelligent Transportation Systems (ITS) make use of advanced technologies to enhance road safety and improve traffic efficiency. It is anticipated that ITS will play a vital future role in improving traffic efficiency, safety, comfort and emissions. In order to assist the passengers to travel safely, efficiently and conveniently, several application requirements have to be met simultaneously. In addition to the delivery of regular traffic and safety information, vehicular networks have been recently required to support infotainment services. Previous vehicular network designs and architectures do not satisfy this increasing traffic demand as they are setup for either voice or data traffic, which is not suitable for the transfer of vehicular traffic. This new requirement is one of the key drivers behind the need for new mobile wireless broadband architectures and technologies. For this purpose, this thesis proposes and investigates a heterogeneous IEEE 802.11 and LTE vehicular system that supports both infotainment and ITS traffic control data. IEEE 802.11g is used for V2V communications and as an on-board access network while, LTE is used for V2I communications. A performance simulation-based study is conducted to validate the feasibility of the proposed system in an urban vehicular environment. The system performance is evaluated in terms of data loss, data rate, delay and jitter. Several simulation scenarios are performed and evaluated. In the V2I-only scenario, the delay, jitter and data drops for both ITS and video traffic are within the acceptable limits, as defined by vehicular application requirements. Although a tendency of increase in video packet drops during handover from one eNodeB to another is observed yet, the attainable data loss rate is still below the defined benchmarks. In the integrated V2V-V2I scenario, data loss in uplink ITS traffic was initially observed so, Burst communication technique is applied to prevent packet losses in the critical uplink ITS traffic. A quantitative analysis is performed to determine the number of packets per burst, the inter-packet and inter-burst intervals. It is found that a substantial improvement is achieved using a two-packet Burst, where no packets are lost in the uplink direction. The delay, jitter and data drops for both uplink and downlink ITS traffic, and video traffic are below the benchmarks of vehicular applications. Thus, the results indicate that the proposed heterogeneous system offers acceptable performance that meets the requirements of the different vehicular applications. All simulations are conducted on OPNET Network Modeler and results are subjected to a 95% confidence analysis
Handover in Mobile WiMAX Networks: The State of Art and Research Issues
The next-generation Wireless Metropolitan Area
Networks, using the Worldwide Interoperability for Microwave
Access (WiMAX) as the core technology based on the IEEE
802.16 family of standards, is evolving as a Fourth-Generation
(4G) technology. With the recent introduction of mobility management
frameworks in the IEEE 802.16e standard, WiMAX
is now placed in competition to the existing and forthcoming
generations of wireless technologies for providing ubiquitous
computing solutions. However, the success of a good mobility
framework largely depends on the capability of performing fast
and seamless handovers irrespective of the deployed architectural
scenario. Now that the IEEE has defined the Mobile WiMAX
(IEEE 802.16e) MAC-layer handover management framework,
the Network Working Group (NWG) of the WiMAX Forum
is working on the development of the upper layers. However,
the path to commercialization of a full-fledged WiMAX mobility
framework is full of research challenges. This article focuses on
potential handover-related research issues in the existing and
future WiMAX mobility framework. A survey of these issues in
the MAC, Network and Cross-Layer scenarios is presented along
with discussion of the different solutions to those challenges. A
comparative study of the proposed solutions, coupled with some
insights to the relevant issues, is also included
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