Current Issue : October - December Volume : 2017 Issue Number : 4 Articles : 5 Articles
An analytical mobility model based on Erlang distribution is introduced to portray sparse and dense traffic scenarios in the\ndistributions of time headway. Upon the mobility model, the connectivity probability is then derived in two-way highway when\nadopting store-forward strategy.Moreover, path losses with and without beamforming antenna array are compared to further study\nthe connectivity under different traffic density scenarios.Meanwhile, the effectiveness of beamforming technology in Vehicular Ad\nhoc Networks (VANETs) is investigated and concluded through analytical study and simulations....
Vehicular Ad Hoc Networks (VANETs) are getting more popularity due to the potential Intelligent Transport Systems (ITS)\ntechnology. It provides many efficient network services such as safety warnings (collision warning), entertainment (video and\nvoice), maps based guidance, and emergency information. VANETs most commonly use Road Side Units (RSUs) and Vehicle-to-\nVehicle (V2V) referred to as Vehicle-to-Infrastructure (V2I) mode for data accessing. IEEE 802.11p standard which was originally\ndesigned forWireless Local Area Networks (WLANs) is modified to address such type of communication. However, IEEE 802.11p\nuses Distributed Coordination Function (DCF) for communication between wireless nodes. Therefore, it does not performwell for\nhigh mobility networks such as VANETs. Moreover, in RSU mode timely provision of data/services under high density of vehicles\nis challenging. In this paper, we propose a RSU-based efficient channel access scheme for VANETs under high traffic and mobility.\nIn the proposed scheme, the contention window is dynamically varied according to the times (deadlines) the vehicles are going to\nleave the RSU range.The vehicles with shorter time deadlines are served first and vice versa. Simulation is performed by using the\nNetwork Simulator (NS-3) v. 3.6. The simulation results show that the proposed scheme performs better in terms of throughput,\nbackoff rate, RSU response time, and fairness....
Weather is a state of atmosphere which tells about degree which is not same everywhere it may be hot or cold, clear or cloudy, wet or dry, calm or stormy. Extreme weather such as deadly heat waves, devastating flood, intense precipitation, drought, heavy rains and flooding are more frequent likewise climate has warmed and changed so certain types of natural limits are more frequent and more intense. VANET is emerging and advance technology for wireless communication which include security, privacy, routing, connectivity and quality of services. During flood people suffer with no transportation, improper drinking water, roads were flooded, ATM’s were down in city, flights were cancelled which brings massive problem to people both as economically and environmentally. By combing weather report and VANET technology, broadcasting historical emergency weather situation message to vehicle by detecting, modeling, predicting dangerous situation on urban road....
This research evaluates the impact of In-vehicle Signal Advisory System (ITSAS) on\nsignalized arterial. ITSAS provides individual drivers equipped with a mobile communication device\nwith advisory speed information enabling to minimize the time delay and fuel consumption when\ncrossing intersection. Given the instantaneous vehicular driving information, such as position, speed,\nand acceleration rate, ITSAS produces advisory speed information by taking into consideration the\ntraffic signal changes at a downstream intersection. The advisory speed information includes not only\nan optimal speed range updated every 300-ft for individual drivers but also a descriptive message to\nwarn drivers stop to ensure safety at the downstream intersection. Unlike other similar Connected\nVehicles applications for intersection management, ITSAS does not require Roadside Equipment\n(RSE) to disseminate the advisory speed information as it is designed to exploit commercial cellular\nnetwork service (i.e., 3G and 4G-LTE). Thus, ITSAS can be easily plugged into existing traffic control\nmanagement system to rapidly conduct its implementation without significant additional cost.\nThis research presents the field evaluations of ITSAS on a signalized corridor in New Jersey, which\ndiscovered significant travel time savings for the equipped vehicle...
An asynchronous medium access control (MAC) duty-cycled protocols have higher energy efficiency and lower\npacket latency than synchronized ones due to reduced idle listening. Moreover, they provide efficient utilization of\nenergy supplied to mobile sensors. They are considered very important in MAC protocols due to the adverse effects of\nhidden terminals which causes energy consumption in sensor networks. Therefore, in this paper, the impact of hidden\nterminals on the performance of an asynchronous duty-cycled MAC protocol X-MAC for vehicle-base sensor is\ninvestigated via analysis and simulations. We propose a Markov model to analyze the quality-of-service (QoS)\nparameters in terms of energy consumption, delay, and throughput. Our analytical model provides QoS parameter\nvalues that closely match the simulation results under various network conditions. Our model is more\ncomputationally efficient and provides accurate results quickly compared with simulations. More importantly, our\nmodel enables the designers to obtain a better understanding of the effects of different numbers of mobile sensor\nnodes and data arrival rates on the performance of an asynchronous MAC duty-cycled protocol....
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