1,093 research outputs found

    VANET: Performance Comparison of BNGF Method in Different Vehicular Traffic Scenarios

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    A Vehicular Ad hoc Network (VANET) is a wireless ad hoc network that is formed between vehicles on an on demand basis. A lot of research work around the world is being conducted to design the routing protocols for VANETs. In this paper, we examine the significance Greedy Forwarding with Border Node based approach for VANETs to optimize path length between vehicles in different traffic scenarios. This protocol is called Border Node Greedy Forwarding (BNGF) since it uses border nodes with Greedy Forwarding. We categorize BNGF as BNGF-H for highway and BNGF-C for city traffic scenarios. We have simulated this protocol using NS-2 simulator and calculated the performance in terms of end-to-end delay and packet delivery ratio. We compare both the methods for highway and city traffic scenarios. The result clearly show that the end-to-end delay for BNGF-C is significantly lower and packet delivery ratio is higher than BNGF-H

    A Distributed Routing Algorithm for Internet-wide Geocast

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    Geocast is the concept of sending data packets to nodes in a specified geographical area instead of nodes with a specific address. To route geocast messages to their destination we need a geographic routing algorithm that can route packets efficiently to the devices inside the destination area. Our goal is to design an algorithm that can deliver shortest path tree like forwarding while relying purely on distributed data without central knowledge. In this paper, we present two algorithms for geographic routing. One based purely on distance vector data, and one more complicated algorithm based on path data. In our evaluation, we show that our purely distance vector based algorithm can come close to shortest path tree performance when a small number of routers are present in the destination area. We also show that our path based algorithm can come close to the performance of a shortest path tree in almost all geocast situations

    Solutions for vehicular communications: a review

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    Vehicular networks experience a number of unique challenges due to the high mobility of vehicles and highly dynamic network topology, short contact durations, disruption intermittent connectivity, significant loss rates, node density, and frequent network fragmentation. All these issues have a profound impact on routing strategies in these networks. This paper gives an insight about available solutions on related literature for vehicular communications. It overviews and compares the most relevant approaches for data communication in these networks, discussing their influence on routing strategies. It intends to stimulate research and contribute to further advances in this rapidly evolving area where many key open issues that still remain to be addressed are identified.Part of this work has been supported by the Instituto de Telecomunicações, Next Generation Networks and Applications Group (NetGNA), Portugal, in the framework of the Project VDTN@Lab, and by the Euro-NF Network of Excellence of the Seventh Framework Programme of EU, in the framework of the Specific Joint Research Project VDTN

    Improving Network Performance with Affinity based Mobility Model in Opportunistic Network

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    Opportunistic network is a type of Delay Tolerant Network which is characterized by intermittent connectivity amongst the nodes and communication largely depends upon the mobility of the participating nodes. The network being highly dynamic, traditional MANET protocols cannot be applied and the nodes must adhere to store-carry-forward mechanism. Nodes do not have the information about the network topology, number of participating nodes and the location of the destination node. Hence, message transfer reliability largely depends upon the mobility pattern of the nodes. In this paper we have tried to find the impact of RWP (Random Waypoint) mobility on packet delivery ratio. We estimate mobility factors like number of node encounters, contact duration(link time) and inter-contact time which in turn depends upon parameters like playfield area (total network area), number of nodes, node velocity, bit-rate and RF range of the nodes. We also propose a restricted form of RWP mobility model, called the affinity based mobility model. The network scenario consists of a source and a destination node that are located at two extreme corners of the square playfield (to keep a maximum distance between them) and exchange data packets with the aid of mobile 'helper' nodes. The source node and the destination node are static. The mobile nodes only help in relaying the message. We prove how affinity based mobility model helps in augmenting the network reliability thereby increasing the message delivery ratio and reduce message delivery latency.Comment: IJWMN Journal, Opportunistic Network, 14 pages, 10 figures with Appendi

    CARAVAN: A Context-AwaRe Architecture for VANET

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    Multi-layer Utilization of Beamforming in Millimeter Wave MIMO Systems

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    mmWave frequencies ranging between (30-300GHz) have been considered the perfect solution to the scarcity of bandwidth in the traditional sub-6GHz band and to the ever increasing demand of many emerging applications in today\u27s era. 5G and beyond standards are all considering the mmWave as an essential part of there networks. Beamforming is one of the most important enabling technologies for the mmWave to compensate for the huge propagation lose of these frequencies compared to the sub-6GHz frequencies and to ensure better spatial and spectral utilization of the mmWave channel space. In this work, we tried to develop different techniques to improve the performance of the systems that use mmWave. In the physical layer, we suggested several hybrid beamforming architectures that both are relatively simple and spectrally efficient by achieving fully digital like spectral efficiency (bits/sec/Hz). For the mobility management, we derived the expected degradation that can affect the performance of a special type of beamforming that is called the Random Beamforming (RBF) and optimized the tunable parameters for such systems when working in different environments. Finally, in the networking layer, we first studied the effect of using mmWave frequencies on the routing performance comparing to the performance achieved when using sub-6 GHz frequencies. Then we developed a novel opportunistic routing protocol for Mobile Ad-Hoc Networks (MANET) that uses a modified version of the Random Beamforming (RBF) to achieve better end to end performance and to reduce the overall delay in delivering data from transmitting nodes to the intended receiving nodes. From all these designs and studies, we conclude that mmWave frequencies and their enabling technologies (i.e. Beamforming, massive MIMO, ...etc.) are indeed the future of wireless communicatons in a high demanding world of Internet of Things (IoT), Augmented Reality (AR), Virtual Reality (VR), and self driving cars

    Optimisation of Mobile Communication Networks - OMCO NET

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    The mini conference “Optimisation of Mobile Communication Networks” focuses on advanced methods for search and optimisation applied to wireless communication networks. It is sponsored by Research & Enterprise Fund Southampton Solent University. The conference strives to widen knowledge on advanced search methods capable of optimisation of wireless communications networks. The aim is to provide a forum for exchange of recent knowledge, new ideas and trends in this progressive and challenging area. The conference will popularise new successful approaches on resolving hard tasks such as minimisation of transmit power, cooperative and optimal routing

    An IOT-enabled System for Marine Data Acquisition and Cartography

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    Current satellite communication remains very expensive and impractical for most small to mid-sized vessels, and at the same time marine wireless networking is lack of network coverage. To solve this problem, this paper proposes a novel IOT (Internet of Things) enabled system for marine data acquisition and cartography based on Ship Ad-hoc Networks (SANET’s). Ships are equipped with Very High Frequency (VHF) radios and several sensors such as sea depth, temperature, wind speed and direction, etc. The collected sensory data is sent to 5G edge clouds incorporated at sink/base station nodes on shore, and ultimately aggregated at a central cloud on the internet to produce up to date cartography. The routing protocols deployed are DSDV (Destination-Sequenced Distance Vector), AODV (Ad hoc On-Demand Distance Vector), AOMDV (Ad hoc On-Demand Multipath Distance Vector) and DSR (Dynamic Source Routing) protocols, which are very popular in Mobile Ad-hoc Networks (MANET’s) and compatible with multi hop routing environments and scalability towards increased traffic and mobility. Simulation results verify the feasibility and efficiency of the proposed system that has packet delivery rates of up to 80% at shore base stations

    Content storage and retrieval mechanisms for vehicular delay-tolerant networks

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    Vehicular delay-tolerant networks (VDTNs) were proposed as a novel disruptive network concept based on the delay tolerant networking (DTN) paradigm. VDTN architecture uses vehicles to relay messages, enabling network connectivity in challenging scenarios. Due to intermittent connectivity, network nodes carry messages in their buffers, relaying them only when a proper contact opportunity occurs. Thus, the storage capacity and message retrieving of intermediate nodes directly affects the network performance. Therefore, efficient and robust caching and forwarding mechanisms are needed. This dissertation proposes a content storage and retrieval (CSR) solution for VDTN networks. This solution consists on storage and retrieval control labels, attached to every data bundle of aggregated network traffic. These labels define cacheable contents, and apply cachecontrol and forwarding restrictions on data bundles. The presented mechanisms gathered several contributions from cache based technologies such as Web cache schemes, ad-hoc and DTN networks. This solution is fully automated, providing a fast, safe, and reliable data transfer and storage management, while improves the applicability and performance of VDTN networks significantly. This work presents the performance evaluation and validation of CSR mechanisms through a VDTN testbed. Furthermore it presents several network performance evaluations and results using the well-known DTN routing protocols, Epidemic and Spray and Wait (including its binary variant). The comparison of the network behavior and performance on both protocols, with and without CSR mechanisms, proves that CSR mechanisms improve significantly the overall network performance
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