Dissemination Techniques in VANET: A Survey

Transcription

1 Dissemination Techniques in VANET: A Survey Ankita Verma #1, Dr Satya Ranjan Patra *2, Prof. Pankaj Richariya #3 #1 Student of CSE dept., Bhopal Institute of Technology & Science #2 Professor, CSE dept., Bhopal Institute of Technology & Science #3 H.O.D., CSE dept., Bhopal Institute of Technology & Science Bhopal- M.P. - India Abstract VANETs (vehicular ad hoc networks) are emerging as a new network environment for intelligent transportation systems. Many of the applications built for VANETs will depend on the data push communication model, where information is disseminated to a group of vehicles. Various Approaches of data dissemination in vehicular network can be used to inform vehicles about dynamic road traffic condition so that a safe and efficient transportation system can be achieved. In this paper, we have reviewed various data dissemination techniques and did the comparison of two important approaches of dissemination. I. INTRODUCTION In today scenario vehicle are increasing day by day on a road, because of that many unwanted events are happen regularly on road, people may injured or lose their lives due to accident on road. Rate of deaths on a road due to accidents is increases day by day, so we need some solution for that. Intelligent Transportation System (ITS) has introduces VANET technology for this purpose, in which information regarding road and traffic conditions are available for drivers before he passes through that road; that timely information escapes driver from traffic jams or other kind of miss happenings. VANETs are ad hoc networks established among vehicles which are equipped with communication facilities. These vehicles are like a network nodes so that each node can act as the source of data, destination for data and a network router. For communication in VANET, US DOT (United States Department of Transportation) has allocated a frequency band of 5.9 GHz in which Dedicated Short Range Communication (DSRC) is used. DSRC ranges up to 1000m, which allows high speed communication between vehicles [1]. These DSRC based applications for public safety and traffic management consist of intersection collision avoidance, warning messages, and approaching emergency vehicle warning etc. VANETs and Mobile Ad Hoc Networks (MANETs) have some similar characteristics such as short range of transmission, omni-directional broadcast low bandwidth and limited storage capacity. They also obtained some different characteristics which are as follows: a) INDEFINITE TOPOLOGY: Because of high speed vehicles, topology is very dynamic on road it is purely relayed on the path which is selected by vehicle node. b) INTERRUPTED LINKS: Because of above characteristic; links are continuously interrupted. In a dense place where vehicle quantities are higher, ratio of link break is less but where vehicles quantities are less link break up is increases with higher rate. To reduce above weakness of VANET we can install road side units nearby road.. c) NETWORK MODELLING: Information about the current position, movement direction, current velocity, city map and planned movement trajectory of VANET nodes is available, as more and more vehicles are equipped with global positioning system devices and navigation systems. d) ENVIRONMENT FOR COMMUNICATION: VANET networks are usually of very large size but also may exist in a form of many small, neighbouring networks with a high probability of splitting and joining. There is a big diversity of VANET services and applications, and one to one communication is less important than some intelligent broadcast required by most safety related applications. e) REAL TIME COMMUNICATION: If any safety message is required send in a network have to be send in real time because any kind of delay in this massage will causes hazardous conditions on a road. f) INSTALLED GADGETS: VANET equipped vehicles have OBU (On Board Units) which helps in providing a location of vehicle and its movement on a road to its neighbour vehicle because of an effective communication link and routing purposes. In VANETs, the restricted road topology imposes a directional nature to the message flow. Also due to higher node speeds and unstable connectivity among the nodes, it becomes essential that data be transmitted in the most efficient ways and with minimal delay. ISSN: Page 83

2 Data dissemination among vehicles depends on the type of assumed network architecture. In the presence of road side units, two data dissemination approaches are assumed: pushbased and pull-based. In the push-based approach data can be sending or broadcast in a network to any one, this approach is suitable for popular data on the other hand pill based approach based on request/reply methodology which suitable for unpopular data. In the absence of infrastructure two dissemination approaches can be considered: flooding and relaying. The flooding approach generally generates high message traffic. Therefore, the main challenge in this approach is to avoid the broadcast storm problem [2]. With relaying approach there are also two challenges that may be encountered: a) Relay point selection; and b) Reliable nodes for re-transmission selection. If the vehicles are provided with updated information regarding road traffic conditions in timely manner, then driver have enough time to take right actions to avoid being trapped in heavy traffic jams. Further we have organized this paper as shown; Section 2 describes how data dissemination takes place in VANET. Section 3 describes our literature survey. Section 4 describes the comparison of different dissemination techniques and section 5 concludes this paper. II. DATA DISSEMINATION IN VANETS The word dissemination means that spreading, so data dissemination means spreading data in all over the network. The concept of data dissemination is wide and useful in VANETs. In this regard vehicle node disseminates information over distributed wireless networks, which is a superset of VANETs. The approach of data dissemination in a network may be classified on the basis of: VEHICLE TO INFRASTRUCTURE DISSEMINATION: a. Push based: In this approach, road side unit s sends or broadcast data into the entire network. If any vehicle wants to send any data it will send it to RSU and then it will deliver in the network. For example, vehicle wants to spread information like E-advertisement, security protocols, etc. b.pull based: In this approach, requested data will be deliver to the intended requester. It means that if any node in a network requests for any kind of information from network it will be deliver to it. For example, Vehicle wants to get weather information. VEHICLE TO VEHICLE DISSEMINATION: a. Flooding: It means to broadcast data in a network. In this approach every node broadcast data in a network to participate in the dissemination process. This approach is good for delay sensitive application and also very much suitable for sparse networks during low traffic conditions. b. Relaying: In this approach sender node can select the relay node this relays node will forward this data to another relay node and so on. Advantage of this approach is that it reduces congestion and it is scalable to dense networks. This approach is generally preferred for congested networks. When the road side unit is not present, vehicle has to relay its data through multiple hops over long distance to deliver it or to access the data from RSU. Although, this kind of data transmission (relay method for long distance) through multiple hop is much more difficult because of high mobility in VANET. It is difficult to find out the end to end connection for a sparsely connected network. Vehicles on urban areas are more likely to form highly dense networks during high rush, while VANETs are expected to experience frequent network fragmentation in sparsely populated rural freeways or during late night hours. Network fragmentation is a fundamental routing issue that needs to be addressed in VANET [3]. In order to forward messages efficiently in dense network situations, the network protocols must manage contention for the bandwidth. In existing literature, data dissemination models are described in two types in VANETs [4], [5]; III. LITRATURE SURVEY Tamer Nadeem in 2012 presents a formal model of data dissemination in VANETs and study how VANET characteristics, specifically the bidirectional mobility on well defined paths, affects the performance of data dissemination. According to author, data push model in the context of Traffic View, a system that has implemented to disseminate information about the vehicles on the road. Traffic data could be disseminated using the cars moving on the same direction, cars moving in the opposite direction, or cars moving in both directions [6]. Koosha Paridel, Yolande Berbers in 2012, surveys the routing techniques in Delay Tolerant Networks, and also the usage of DTN communication in VANETs. Then, they propose a combined architecture of Vehicle-to-Vehicle ISSN: Page 84

3 communication, DTN communication, and Vehicle-to-Infrastructure communication as a large-scale data dissemination system for vehicular networks. Author argue that the combined architecture enables data dissemination in a larger geographical area compared to a V2V communication model, and efficiently deals with disconnectivity and network partitions that mostly occurs in sparse networks [7]. Tulika in 2011, proposes publish/subscribe framework for information dissemination in VANET. In her approach, she assumed a hybrid VANET consisting of stationary info-stations and moving vehicles where each vehicle can take the role of publisher, subscriber or broker. Every major crossing of city is equipped with stationary infostations that act as ultimate place holders for publications and subscriptions. These info-stations are assumed to be connected to internet and form Distributed Hash Table based broker overlay among them. They act as rendezvous point for publications and subscriptions and send matching publications to interested subscribers [8]. Ilias Leontiadis in 2007, proposes a design for P/S Middleware for vehicular networks that considers location and time in its primitives. Author would like to enable the application developers to easily publish notification in specific location by treating location as context. He will use subscriptions and the navigation system to automatically express interests on the affected vehicles and to filter incoming notifications. Middleware incorporates the appropriate communication mechanisms that implement the tasks instructed by the middleware primitives [9]. Shea, C in 2009, presents a novel, mobility-based clustering scheme for Vehicle Ad hoc Networks, which utilizes the Affinity Propagation algorithm in a distributed manner. The proposed algorithm considers typical vehicular mobility during cluster formation, which produces clusters with high stability. Simulation results confirm the superior performance of the proposed algorithm, when compared to other accepted mobility-based clustering techniques. Clustering performance is measured in terms of average cluster head duration, average cluster member duration, average rate of cluster head change, and average number of clusters [10]. Shou-Chih Lo in 2013 presents a new clustering algorithm that considers both node position and node mobility in vehicular ad hoc environments. The proposed algorithm intends to create stable clusters by reducing re-clustering overhead, prolonging cluster lifetime, and shortening the average distance between cluster heads and their cluster members. Most important, this algorithm supports single and multiple cluster heads [11]. IV. COMPARING DIFFERENT TECHNIQUE OF DISSEMINATION As per the above literature survey we find that there are mainly two types of data dissemination model; first is vehicle to infrastructure and second is vehicle to vehicle communication model. There are two different techniques for data dissemination, first is Clustering Based & second is Publish/Subscribe method. Comparison of above techniques is as follows: a) CLUSTRING APPROCH: In Clustering approach, formation of stable clusters with also checks of the mobility pattern of the vehicles which is a key factor for clustering in VANET. Many clustering schemes have been proposed by the researchers which can be classified into either mobility based clustering or nonmobility based clustering algorithms. In mobility based clustering, mobility characteristic of vehicles as one of the parameters for selecting clusters and cluster heads in the network. The other characteristics of a vehicle are position, direction, speed, etc. The mobility based clustering techniques can be further classified into two types depending on the direction taken by the vehicles on road. They are direction based clustering schemes and non-direction based clustering schemes. And in non-mobility based clustering algorithms the nonmobility based schemes are the vehicular ad hoc network schemes which use clustering technique but don t use mobility as one of the metrics [10]. i.clustring IN VEHICLE TO VEHICLE: In Vehicle to Vehicle clustering, group of close vehicle select a cluster head which works a head of that cluster and all the traffic in that cluster is passed by it. Because of this approach link failure problem shall be solve at some extant. 1-1 Clustering V -V ISSN: Page 85

4 ii. CLUSTRING V TO I: In Vehicle to Infrastructure clustering, Head cluster is communicate with the road side unit for all the sub partner on its cluster because of this approach load on RSU is decreases. Error! Use the Home tab to apply 0 to the text that you want to appear here.-3 V to V Publish / subscribe 1-2 Clustering V - I b) PUBLISH & SUBSCRIBE APPROACH: Publish/subscribe method [8] has been emerged as the most suitable communication technique for building applications where underlying interaction mechanisms are required to be asynchronous which is highly dynamic and flexible in nature. The main strength of this technique depends upon its space and time decoupling and flow of data between event consumers whom we called subscribers and event producers, called publishers. Another component, called broker, it acts as a mediator between publishers and subscribers, it assists in creating a decoupled environment where subscribers and publishers are unaware about each other and can dynamically leave or join the system. Vehicular ad-hoc network is a delay tolerant network and anonymity, asynchrony and autonomy are its inherent characteristics. Decoupling in time means the event subscriber and event publisher need not be up at the same time. Decoupling in flow means sending and receiving does not block participants. Decoupling in space means the subscriber can move from one location to another without informing the publisher. I.PUBLISH/ SUBSCRIBE VEHICLE TO VEHICLE In Vehicle to Vehicle communication under publish/subscribe method, information sender vehicle have to publish its data in a network and receiver vehicle have to subscribe that information from the network. Vehicle passes its data packet to another vehicle and so on. Because of its broadcasting nature information can be easily delivered to its destination. ii.publish/ SUBSCRIBE VEHICLE TO INFRASTRUCTURE In Vehicle to infrastructure communication under publish/subscribe method, sender can send its data to the road side unit, and then RSU spread this information to entire network. Error! Use the Home tab to apply 0 to the text that you want to appear here.4 V to I Publish / Subscribe TABLE 1.1 Clustering Dense Unpopulated Dense Publish / Subscribe Unpopul ated Pull Approach Excellent Excellent Good Poor Push Approach Good Excellent Good Low Flooding Good Excellent Good High Relaying Average Average Average Poor V. CONCLUSION: Vehicular Ad Hoc Networks is an effective tool for improving road safety through propagation of warning messages among the vehicles in the ISSN: Page 86

5 network about potential obstacles on the road ahead. For to do so it is very important that data dissemination shall be good in network. In this paper, we have survey different approaches for data dissemination in VANET. We have also compare two main techniques used in VANET for data dissemination; clustering approach and publish/ subscribe approach and our tabular comparison have leads us to conclude that for the present scenario clustering technique is more effective than the publish/ subscribe method. REFERENCES [1] [2] N. Wisitpongphan, O. K. Tonguz, J. S. Parikh, P. Mudalige, F. Bai, and V. Sadekar, Broadcast storm mitigation techniques in Vehicular Ad hoc Networks, IEEE Wireless Communications, vol. 14 (6), pp , [3] J. Zhao and G. Cao, VADD: Vehicle-Assisted Data Delivery in Vehicular Ad Hoc Networks, In proceedings of IEEE Infocom, 2006, pp [4] J. Zhao, Y. Zhang and G. Cao, Data Pouring and Buffering on the Road: A New Data Dissemination Paradigm for Vehicular Ad Hoc Networks, In IEEE transactions on vehicular technology, Vol. 56, No. 6, 2007, pp [5] T. Nadeem, P. Shankar and L. Iftode, A Comparative Study of Data Dissemination Models for VANETs In 3rd ACM/IEEE Annual International Conference on Mobile and Ubiquitous Systems: Networks and Services (MOBIQUITOUS 2006), 2006, pp [6] Tamer Nadeem, Pravin Shankar, Liviu Iftode, A Comparative Study of Data Dissemination Models for VANETs in 2012, research gate. [7] ] Koosha Paridel, Yolande Berbers, VVID: A Delay Tolerant Data Dissemination Architecture for VANETs Using V2V and V2I communication, MOBILITY 2012 : The Second International Conference on Mobile Services, Resources, and Users. [8] Tulika, Deepak Garg, Manoj Madhav Gore, A Publish/Subscribe Communication Infrastructure for VANET Applications, in 2011 Workshops of International Conference on Advanced Information Networking and Applications,2011 IEEE. pp [9] Ilias Leontiadis, Publish/Subscribe Notification Middleware for Vehicular networks, in 2007, Proceeding MDS '07 Proceedings of the 4th on Middleware doctoral symposium Article No. 12 ACM New York, NY, USA [10] Shea, C.; Hassanabadi, Behnam; Valaee, S., "Mobility- Based Clustering in VANETs Using Affinity Propagation," Global Telecommunications Conference, GLOBECOM IEEE, vol., no., pp.1,6, Nov Dec [11] Shou -Chih Lo, Yi - Jen Lin, and Jhih-Siao Gao, A MultiHead Clustering Algorithm in Vehicular Ad Hoc Networks. International Journal of Computer Theory and Engineering, Vol. 5, No. 2, April ISSN: Page 87