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ITS Telecommunications (ITST), 2013 13th International Conference on

Date 5-7 Nov. 2013

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Displaying Results 1 - 25 of 85
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    Freely Available from IEEE
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    Freely Available from IEEE
  • An efficient and reliable multi-hop geographical broadcast protocol in Vehicular Ad-hoc Networks

    Page(s): 1 - 7
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1560 KB) |  | HTML iconHTML  

    In Intelligent Transportation Systems (ITS), disseminating warning messages in a timely and efficient way through wireless short-range communications can save many lives and reduce traffic congestion. A geographical broadcast protocol provides data delivery to specified geographical areas, using multi-hop communications if needed. Among the main challenges for such protocols are forwarder selection and the reduction of the number of hops required to reach and cover the destination area. In this paper we propose an efficient geographical broadcast protocol called Preferred and Contention Based Forwarding (PCBF) and evaluate it through simulations. PCBF uses a combination of contention-based forwarding and selecting preferred forwarders also found in other protocols like Emergency Message Dissemination for Vehicular Environments (EMDV). Since the preferred forwarder is allowed to immediately forward the packet (evading contention among other potential forwarders), this approach reduces end-to-end delays. Notable extensions of PCBF compared to EMDV are the use of direct negative acknowledgements in case of unnecessary rebroadcasts and the use of forwarders outside the target region. Our simulation results show that the PCBF protocol outperforms selected other protocols in terms of end-to-end delay, re-broadcast overhead and reliability in both sparse and dense networks. View full abstract»

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  • Analysis of Cooperative Awareness Message rates in VANETs

    Page(s): 8 - 13
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (906 KB) |  | HTML iconHTML  

    To support applications for environment perception in Vehicular Ad-Hoc Networks (VANETs), vehicles send Cooperative Awareness Messages (CAMs) via wireless broadcast to inform other vehicles about their status. Each message received by a vehicle is processed by several application modules that run on hardware with limited resources whose capacity is not yet defined. Therefore, the received rate of CAMs is a crucial input for the development of series VANET products. In this paper, we quantify the received rate of CAMs and show that it can be high even for a low fraction of vehicles generating CAMs. We simulate road traffic in typical highway scenarios and estimate sent CAM rates. We introduce the notion of relative channel load and present a new approximative channel model to determine a vehicle's message reception probability. We use that model to simulate a vehicle's received CAM rates and propose a simple approximation formula. View full abstract»

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  • Using hybrid AOA/TOA information for distributed topology control in VANETs

    Page(s): 14 - 19
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1929 KB) |  | HTML iconHTML  

    In a vehicular ad-hoc network (VANET), the network topology may change frequently. Consequently, the key design issue is how to organize nodes effectively such that the topology can be stabilized quickly. In order to balance the load among the nodes and govern the topology change, a group formation scheme using localized criterions is implemented. The proposed distributed topology control method focuses on reducing the rate of group member change and avoiding the unnecessary information exchange. Two phases are sequentially applied to choose the group members of each node using hybrid angle-of-arrival (AOA) and time-of-arrival (TOA) information. The operation of Phase I is based on the concept of the cone-based method, which can exclude a lot of nodes quickly. Afterwards, the proposed time-slot method is further applied to stabilize the network topology. Given the network structure in Phase I, the routing group member is determined by Phase II operation. The proposed scheme is simulated and analyzed to abstract the network behaviors in a number of settings. The experimental results show that the proposed algorithm provides efficient network topology management and achieves high scalability in VANETs. View full abstract»

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  • Fast and Reliable Hybrid routing for Vehicular Ad hoc Networks

    Page(s): 20 - 25
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (683 KB) |  | HTML iconHTML  

    Intelligent Transportation Systems (ITSs) have been attracting tremendous attention in both academia and industry due to emerging applications that pave the way towards safer enjoyable journeys and inclusive digital partnerships. Undoubtedly, these ITS applications will demand robust routing protocols that not only focus on Inter-Vehicle Communications but also on providing fast, reliable, and secure access to the infrastructure. In this paper, we propose a Fast and Reliable Hybrid routing (FRHR) protocol for efficient infrastructure access which is capable of handling efficient vehicle to vehicle communications. Interface to infrastructure is provided by carefully placed RoadSide Units (RSUs) which broadcast beacons in a multi-hop fashion in constrained areas. This enables vehicles proactively to maintain fresh minimum-delay routes to other RSUs while reactively discovering routes to nearby vehicles. The proposed protocol utilizes RSUs connected to the wired backbone network to relay packets toward remote vehicles. A vehicle selects an RSU to register with according to the expected mean delay instead of the device's remoteness. We demonstrate the efficiency and robustness of the routing protocol through simulation experiments performed with accurate mobility and propagation models. View full abstract»

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  • Performance evaluation of DS-CDMA IVC scheme and CSMA/OFDM IVC scheme

    Page(s): 26 - 31
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1924 KB) |  | HTML iconHTML  

    The inter-vehicle communication (IVC) systems based on CSMA/OFDM scheme such as IEEE802.11p or ARIB STD-T109 in Japan are widely developed because autonomous distributed networks are easily made by using the Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) MAC protocol. However, the hidden terminals in CSMA networks cause the performance degradation. In our previous study, a new IVC scheme using Code Division Multiple Access (CDMA) had been proposed to mitigate the impact of hidden terminals and evaluated the performance in the simple straight road model. However, performances of both IVC schemes are not evaluated in the urban area road model assuming multipath fading. In this paper, performances of the DS-CDMA IVC scheme and CSMA/OFDM IVC scheme are evaluated in urban area road model. As the results of simulations, it was confirmed that the PER (Packet Error Rate) performances of CSMA/OFDM IVC can be made better than the DS-CDMA. On the other hand, DS-CDMA shows the possibility that it is able to achieve a low delay communication as compared with CSMA/OFDM. View full abstract»

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  • The impact analysis of traffic incident and prediction model on travel time under incident condition

    Page(s): 32 - 37
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (668 KB) |  | HTML iconHTML  

    Understanding the impact of traffic incidents, not only can help decision-makers choose a better strategy, but also provide travel recommendations for travelers. This paper uses real GPS data collected from probe vehicle to analyze the impact of incident in urban traffic network. Queuing length and incident duration are used to evaluate impact level incident. Then, a traffic incident pattern classification method based on queuing length variation is proposed to more clearly understand the characteristics of traffic incident. At last, we propose a prediction model on the time that a vehicle takes to pass through the location where traffic incident happens by using the GPS position and velocity information. View full abstract»

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  • Vehicle clustering algorithm for sharing information on traffic congestion

    Page(s): 38 - 43
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1670 KB) |  | HTML iconHTML  

    We present a method for clustering vehicles that are in the same congested traffic flow. Our goal is to provide a mechanism for sharing information between vehicles in the same situation to ease traffic congestion in urban areas. Because the most accurate source of information about the congested traffic flow is the vehicle at the head of the traffic flow, it first needs to be identified. To do so, we adapt a clustering algorithm by trajectory abstraction. By grouping the vehicles that have the same or similar trajectory into the same cluster, the vehicle at the tail of the traffic flow can discover the vehicle at the head of the traffic flow. Moreover, we adapt an abstracted trajectory representation to compensate for the error in GPS information. Simulation results show that the proposed algorithm provides a higher rate of correctness than existing commonly used clustering algorithms. View full abstract»

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  • Map-reduce for calibrating massive bus trajectory data

    Page(s): 44 - 49
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (294 KB) |  | HTML iconHTML  

    Accurate bus trajectory data is the basis of many public transportation applications. However, trajectory data sampled by GPS devices contains notable direction errors. We cannot determine the travelling direction of the bus through trajectory data. To address this problem, we utilize k-nearest neighbor algorithm (K-NN) to determine the direction of the bus trajectory. Meanwhile, the voluminous bus trajectory data accumulated daily need to be process efficiently for further data mining. To meet the scalability and performance requirements, in this paper, we use Map-Reduce programming model for trajectory data direction correcting and projecting the bus GPS point to the road link. Particularly, we compare execution time through setting different amount of reduce to express the extent of running time can be affected. Experimental results indicate that the K-NN algorithm improves the accuracy of the direction field in raw bus trajectory data significantly. By comparing the efficiency under different reduce quantities. The result shows that parallel processing framework improves the computational efficiency by a factor of 2 at least, obtaining. View full abstract»

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  • An approach to increase fuel economy with traffic signals

    Page(s): 50 - 55
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (473 KB) |  | HTML iconHTML  

    The UNs projected that half of the world's population would live in urban areas at the end of 2018. By 2050 it is predicted that 64.1% and 85.9% of the developing and developed world respectively will be urbanized. This incredibly rapid growth of megacities causes severe ecological, economical and social problems. The rapid growth of megacities and vehicles are causing a severe fuel consumption and the greenhouse effect in the intersection. In this paper we present an approach for more fuel-efficient driving with traffic signals to avoid unnecessary acceleration in the intersection. The proposed method is capable of informing economical speed of vehicle between intersections. It is an object of this paper to allow for economical driving by reducing the fuel cost, and minimize environmental pollution by minimizing the exhaust gas of vehicle. View full abstract»

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  • Location tracking prevention with dummy messages for vehicular communications

    Page(s): 56 - 61
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (608 KB) |  | HTML iconHTML  

    In emerging vehicular communication systems, each vehicle periodically broadcasts safety messages, which contains various vehicle parameters such as location and velocity. While safety messages are designed for advanced road safety and traffic efficiency, a significant concern is that eavesdroppers can track the vehicle's trajectory. In particular, this tracking is easily performed in low vehicle density environments. To address this location privacy issue, we propose a location privacy protection method in such environments using dummy node messages. In our approach, from an eavesdropper's view, the vehicle density is increased by the generation of dummy node messages. Simulation results show that our proposed method reduces tracking probability in high/low vehicle density environments. View full abstract»

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  • Analysis of the Optimal Cooperation Scope of Bandwidth Sharing in vehicular networks

    Page(s): 62 - 67
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (516 KB) |  | HTML iconHTML  

    This paper investigates the Optimal Cooperation Scope (OCS) for Cooperative Bandwidth Sharing (CBS) in vehicular networks. Three relay schemes based on optimal single path relay and opportunistic relay for multihop CBS are proposed and studied. The OCS is solved as the maximum physical distance or hops between the bandwidth requester and bandwidth helper in the optimal solution to maximize the CBS benefit. OCSs for different environments and with different relay schemes are given in the paper. The results indicate that the OCS is sensitive to the cost weight and may also be larger when using a proper opportunistic relay based scheme than using the optimal single path based one. View full abstract»

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  • Beacon delivery over practical V2X channels

    Page(s): 68 - 73
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (728 KB) |  | HTML iconHTML  

    The problem of modelling V2X system based on partial (RSSI) measurements of the wireless propagation channel is considered. The study shows that the dual slope linear model well approximates pathloss in the V2X systems. We also show that in addition to distance dependent pathloss, incorporation of fast fading as well as its frequency selectivity have significant effect on the overall performance of the system. Interference from simultaneous transmissions is estimated based on medium access control (MAC) and realistic road traffic models. Our simulation results show how car traffic parameters and MAC behavior provide direct impact on the effective communication range of the V2X system. View full abstract»

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  • Providing ubiquitous communication using road-side units in VANET systems: Unveiling the challenges

    Page(s): 74 - 79
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (580 KB) |  | HTML iconHTML  

    Vehicular Ad-Hoc Networks (VANETs) are a long-term solution contributing significantly towards Intelligent Transport Systems (ITS) in providing access to critical life-safety applications and services. Although Vehicular Ad Hoc Networks (VANETs) are attracting greater commercial interest, current research has not adequately captured the real-world constraints in VANET handover techniques. Therefore, in order to have the best practice for VANET services, it is necessary to have seamless connectivity for optimal coverage and ideal channel utilization: this comes at the cost of overlapping signals of adjacent RSUs. This overlapping effect can be investigated using concepts such Network Dwell Time, Time Before Handover and Exit Times. In this simulation study we investigate the feasibility and benefits of providing a ubiquitous communication in VANET under different mobile environments. We also study the impact of beacon frequency and velocity on Network Dwell Time, Time Before Handover and Exit Times, which will help us to predict the handover times and thus make proactive handover possible. Therefore understanding handover issues is critical in supporting life-safety applications and services in VANETs. View full abstract»

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  • Activity recognition for triggering cooperative networking among on-vehicle smart devices

    Page(s): 80 - 84
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1208 KB) |  | HTML iconHTML  

    Wireless communication provides convenience service for mobile devices. Considering different wireless characteristics, e.g., WIFI and 3G/4G, a mobile device user may manually change its wireless connection. For intelligent devices, users hope to keep the cooperative networking to work in background automatically. The paper introduces a new method of triggering cooperative networking among portable devices, which is named Active Cooperative Networking Recognition Method (ACNRM). Considering the increasing sensing ability of current smart devices, the method exploits accelerometers in smart devices to recognize some featured activities of the device users, and then trigger different networking operations. The method assists mobile devices to be aware of the changes in their environments without sending periodical message beacons. Thus it can be used for temporary networking among smart devices on vehicles and can save the networking cost. View full abstract»

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  • Detection and visualization of potential traffic hotspots in urban environments

    Page(s): 85 - 89
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1584 KB) |  | HTML iconHTML  

    In this paper we present a novel contribution work, describing a system that helps to detect urban areas with high density of incidents or risk situations. Our system has a perception and pre-collision system that feed an expert system aimed at detecting dangerous situations. All incidents gathered by the vehicles are sent to a global repository, and its data is processed for detecting urban hotspots where the density of incidents is very high. That information can be useful for city councils, allowing them to address these areas with a high concentration of risk situations. View full abstract»

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  • Dynamic ramp metering approach for an urban highway using microscopic traffic simulation

    Page(s): 90 - 96
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1217 KB) |  | HTML iconHTML  

    In this study, dynamic ramp metering approach has been applied on Levent ramp of Istanbul Outer Beltway (O-2) on which Fatih Sultan Mehmet (FSM) Bridge is located. In this context, field measurements at the related highway intersection have been obtained from highway authority in order to determine the pattern of the traffic, which fluctuates all day long. The most important output of the study is to test the ALINEA control mechanism, which may smooth the traffic flow on O-2. The algorithm has been implemented in PTV VISSIM microscopic traffic simulation environment. Obtained results have shown that even a standalone dynamic ramp metering process can be alleviated the traffic congestion on an urban highway sufficiently. View full abstract»

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  • Knowledge base approach for developing a mobile personalized travel companion

    Page(s): 97 - 103
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (749 KB) |  | HTML iconHTML  

    Nowadays with the proliferation of a panoply of smartphones and tablets on the market, almost everyone has access to mobile devices, which offers better processing capabilities and access to new information and services. Taking this into account the demand for new and more personalized services which aid users in their daily tasks is increasing. Current navigation systems lack in several ways in order to satisfy such demand, namely, accurate information about urban traffic in real-time, possibility to personalize the information used by such systems and also the need to have a more dynamic and user friendly interaction between device and traveler. In short, the current navigation systems were not designed to be intelligent enough to communicate their needs effectively to humans, and they are not intelligent enough to understand humans' attempts to satisfy those needs. This paper presents an approach for developing a personalized mobility knowledge base to be used by a mobile travelling companion application, whose conversational interactions crowdsource information about the world for the purpose of providing highly specific assistance and recommendations to the user. The work presented here, is still part of on-going work currently addressed under the EU FP7 MobiS project. Results achieved so far do not address the final conclusions of the project but form the basis for the formalization of the MobiS domain knowledge along with the MobiS data models. View full abstract»

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  • Mitigating location and speed errors in floating car data using context-based accuracy estimation

    Page(s): 104 - 110
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (579 KB) |  | HTML iconHTML  

    Although the floating car data contains detailed behavior of vehicles, most researches utilizing the floating car data mainly focus on providing link-level, large-scale traffic estimation because raw floating car data usually contains location and speed errors due to the characteristics of on-board sensors such as GPS and tachometers. Such errors are usually vehicle-dependent and considered hard to be eliminated. To tackle the challenge, in this paper, we propose a method to mitigate location and speed error in raw floating car data. The method takes two different information sources from GPS and tachometers respectively, and relies more on “more dependable” source. The dependability is assessed based on the locations and situations where the data are observed (e.g. in urban canyons the accuracy of GPS decreases and tachometers are more reliable). By analyzing and modeling such characteristics, we eliminate errors contained in those information sources to obtain more accurate traces and behavior of vehicles. We have evaluated our method using the real floating car data obtained over 7 days from 4777 vehicles that have installed commercial on-board navigation systems. We have shown that the relative distance errors have been reduced from 3.84% to 2.86% in 81.6% of vehicles. View full abstract»

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  • A novel traffic light management mechanism on intersection

    Page(s): 111 - 115
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1344 KB) |  | HTML iconHTML  

    Currently, most traffic lights at street intersections operate according to a fixed setting. However in reality, vehicle flow rates of each direction are not always equivalent. As a result, the traffic light at the vertical roadway may turn red when no car is driving on the horizontal roadway, or remain in red when all cars on the horizontal roadway have passed the intersection. In this paper, we develop a novel traffic light management to relieve these situations. Besides, at cooperative vehicular safety environment of WAVE/DSRC, each vehicle installs an OBU that periodically broadcasts its current moving status. In addition, our proposed adaptive traffic light management mechanism will collect and analyze the information broadcasted by all OBUs. Hence, the traffic lights are able to dynamic adjust according the current vehicle flow rates of each direction and further reduce the red light waiting time and increase the traffic throughput at the street intersection. View full abstract»

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  • Performance analysis of real-time streaming under TCP and UDP in VANET via OMNET

    Page(s): 116 - 121
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (601 KB) |  | HTML iconHTML  

    Ad hoc network is composed of mobile nodes without infrastructure. Depending on a hop-by-hop basis of connection, communications between high-mobility nodes are accomplished via cooperative forwarding. Especially, the vehicular ad hoc network (VANET) is a technology that uses moving cars as nodes to create a mobile network or implement vehicle-to-vehicle (V2V) connection. However, the discussion about live streaming or comparative performance in V2V has been lacked so far. We propose a V2V streaming on OMNet platform (VSOP) to build a V2V evaluation of real-time multimedia streaming under TCP/ UDP on VANET. We not only compare TCP and UDP, but also analyze and simulate the routing performance in VANET. The major contribution of proposed scheme is a compared study of protocols for real-time wireless application. View full abstract»

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  • On the fingerprints dynamics in WLAN indoor localization

    Page(s): 122 - 126
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2574 KB) |  | HTML iconHTML  

    Location Based Services require seamless tracking of human or object outdoor/indoor anywhere, everywhere. Based on its location and availability, it should make use of the underlying wireless system it has access to or it could process. In terms of vehicular system also, it requires seamless tracking also in the indoor parking or places where it lacks clear LOS and has to depend upon the widely accessed Wireless Local Area Network based localization. This paper focuses on Received Signal Strength measurements dynamics in WLAN indoor localization. Real-field measurement data taken 3 year apart in the same university building (situated in Tampere, Finland) are used for this analysis. The building AP network has undergone a substantial structural change in between the two sets of measurements, in such a way that most WLAN emitters were replaced and renewed. We study here the variability and dynamics of the indoor channel and accuracy of the positioning results when emitter configuration is changed, but the indoor scenario remains the same (same building structure, same rooms and furniture). View full abstract»

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  • Adage mobile services for ITS infrastructure

    Page(s): 127 - 132
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1152 KB) |  | HTML iconHTML  

    Modern Intelligent Transport Systems (ITS) are based on specific services that are hosted at the edge of network infrastructure. These services are created using the vehicle embedded computing appliances, private cloud resources and global available information services. Within proposed approach all vehicles are considered as mobile part of low level operation network that providing low latency and requested QoS characteristics for ITS communication and information systems. More over some of the discussed decisions support multiprotocol interactions and predictable real time performance so can be used for different kind of industrial, transport and robotics applications. ITS supplemented by low level operation network expands opportunity for practical implementation of emerging Internet of Things (IoT) concept. Thanks to wide functional ability proposed approach is well positioned for big data and on demand high performance applications. Some aspects of these services develops ideas of CISCO' Fog Computing [1] and may be seamlessly supported into existing ITS cloud infrastructure using virtual firewall appliances which provides bilateral access control between vehicles that belongs to MESH network and IaaS segments resources of which support high performance computing or even supercomputers services [2]. View full abstract»

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  • A reputation system to identify and isolate selfish nodes in Vehicular Delay-Tolerant Networks

    Page(s): 133 - 138
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (789 KB) |  | HTML iconHTML  

    Vehicular Delay-Tolerant Networks (VDTNs) were proposed as a solution to overcome some issues found in other vehicular technologies. VDTNs assume the bundle layer placement under the network layer. This vehicular architecture can be applied in sparse regions characterized by sparse connectivity, long propagation delays, high error rates, and short contact durations. Although some of the major issues were already solved and several improvements were already achieved, VDTNs still have several issues that should be overcome. One of these issues is related with nodes cooperation and nodes share their own resources to deliver packets from others. This can be a difficult task if selfish nodes affect the performance of cooperative nodes. To detect, identify, and avoid communications with selfish nodes, this paper proposes a reputation system with four different reputation mechanisms and studies their impact on the performance of the network. This reputation system is enforced on two different routing protocols (Spray-and-Wait and GeoSpray). Across all the experiments, it was shown that reputation mechanisms that punish aggressively selfish nodes contribute to an increase of the overall network performance by increase the number of delivery messages and decrease the message average delivery delay. View full abstract»

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