Reduces Broadcast Storm Using Clustering in VANETs

Transcription

1 International Research Journal of Applied and Basic Sciences 203 Available online at ISSN X / Vol, 7 (3): Science Explorer Publications Reduces Broadcast Storm Using Clustering in VANETs Aylin Deljavan Ghodrati. Graduated in Computer Science of University of Tabriz (Aras Branch) Iran Corresponding Author ailindeljavan@yahoo.com ABSTRACT: VANET is an example of a mobile network which is created for communication between neighboring vehicles. The main objective of VANET is providing safety and comfort for passengers. These networks are examined in two cases: networks with no infrastructure and network with infrastructure. Networks with infrastructure don ' t use, due to high costs. In networks without infrastructure, the main challenge is publication of warning message that, if not manage cause storm broadcast.therefore, many methods have been proposed to manage broadcasting storms that, between them, clustering methods for managing broadcast storms,provide better performance than other methods in terms of success and collisions rate. Therefore, in this essay the idea of management of broadcasting storm is presented based on distributed clustering.that show better performance in terms of collisions, the success rate and delay of CBE-Cast. Simulation shows the performance of the proposed idea. Keywords: broadcasting of warning message, clustering, ad-hoc networks, VANET, delay. INTRODUCTION With increasing advances in science and technology, try using them to solve problems and process optimization are discussed. One of the technologies proposed in vehicle transportation networks, is VANET, which can contribute to the transport industry, road management and productivity improvement in related institutions. Defined application for this technology is: reduce traffic problems, prevention of road accidents, improve the management of necessary actions after road accidents, control the credit of documents and other statistical and welfare applications (Sutariya and Pradhan, 200). Traffic simulation and transportation networks, has been remarkable software development. But they need to keep pace with hardware advances. In addition, simulators to obtain real results, require to consider the relevant parameters. Although VANET confronts with economic, social and technical problems, but the automotive industry to achieve a growing state, should consider world technologies like VANET, to overcome the issues such as improving the management of road accidents, reducing accidents and dealing with the victims status.vanets are ad hoc networks of vehicles that create among the vehicles that create among the vehicles equipped with communication facilities. These vehicles are like network nodes therefore each node can act as a data source, destination, and routing for data networks. VANETs are efficient tools to improve road safety through propagation of warning messages among vehicles in network about the potential barriers of ahead roads (Sutariya and Pradhan, 200). Therefore, data dissemination in VANET has important role in security and non-security applications. For example, if the vehicle has accident in highway, emergency information's will be published as soon as possible to aware the vehicles may hazard due to this accident.second area is related to traffic and transportation control. And use of VANET improves the efficiency of the traffic system. The purpose of data dissemination is to use network resources in order to satisfy the users requirements. Each participating vehicle in VANET makes periodic reports on traffic conditions (Tomar et al., 200). Data dissemination among vehicles is dependent on the type of network architecture. If there be network infrastructure in roadside there are two ways for data publication: ) push-based 2) pull- based. In the push-based method, data can spread to all. But in the pull-based method transferring of data is based on request and response. In the absence of infrastructure two approaches considered for publication: ) Overflow 2) Relays. Overflow approach, causes many traffic. So the main challenge that we face is avoiding the broadcasting storm

2 Intl. Res. J. Appl. Basic. Sci. Vol., 7 (3), , 203 problem. In the relays approach we face with two other problem: ) Select the relays nodes 2) Ensure the reliability when the selected nodes participate in retransmission (Sutariya and Pradhan, 200). Many methods have been proposed to mitigate the broadcast storm. Simple broadcast algorithms, the simplest protocol in V2V used application is the safety alerts in the VANET networks. P-persistence algorithm with using a random selection method attempt to reduce broadcast storm problems and decide which of the vehicles to spread the warning message again. When a vehicle receives a broadcast message for first time, the car spread warning message with a P-random chance. This method helps to reduce the number of relay vehicles and the broadcast storm problem (Rezaei, 2009). Lee and colleagues propose a new broadcasting protocol called efficient directional broadcast (EDB) for VANET with directional antennas. When a vehicle broadcasting in roads, only the farthest receiver has duty to relay the message in the opposite direction that packet has been received from that direction (Li et al., 2007). Algorithm CBE-cast is an algorithm based on clustering for reduce the broadcast storm which choose a node for relay that has the best condition for publicationin this essay the idea of reducing the broadcast storm proposed by clustering (Deljavan Ghodrati and Mohammadkhanli, 203). The paper is organized as follows: In section 2 we review related works. Section 3, presents an algorithm to use clustering to reduce the broadcast storm. Section 4 presents the results of simulation with existing nodes. Finally, we give conclusions in section 5. Related Works In the network of VANET broadcasting done by effective tools for publication of warning message in traffic accidents. However, because of the exclusive features of VANET network, using traditional algorithm for broadcasting in Ad-hoc networks in VANET, can directly reduce the algorithm working efficiency or even cannot work correctly. This section presents the proposed broadcast storm mitigation techniques reviewed in the literature which focuses on this issue. Simple broadcasting Simple broadcasting, the simplest protocol used in V2V applications is safety alerts in the VANET networks. when there is an accidents, the alert software send warning message to all vehicles that are approaching the accident site.when a vehicle received a broadcast message for first time, retransmits it.this car ignores all next broadcastings that have been sent from other vehicles, that these messages are the same messages with the same ID. There are two main problems with simple broadcasting: )due to the message flooding there are many repeated messages.thus, when there is N host for first time, there will be a high probability of receiving N duplicate message by many hosts which are in close by neighborhood.each of hosts competed fiercely with each other for access to the media. As shown in the following figure, when an accident a curse on the road, B, C, D, E and F, which are used to transfer messages, receive warning message and proceed to broadcast it. 2) This approach will lead to the emergence of broadcast storm, which lead to retransmission and further collision (Suriyapaibonwattana and Pomavalai, 2008; Bae, 20). Figure. Conditions of an accident and vehicle near to it on the road (Bae, 20) P-persistence algorithm P-persistence algorithm by using a random selection method, attempt to reduce the broadcast storm problem, and decide which of the vehicles broadcast the warning message again. When a car receives a broadcasting message for first time, the car broadcast the warning message with P-random probability.this method helps to reduce the relay vehicles and broadcasting storm problem. of course, this will cause loss of warning messages for example, if all of the E,D,B,C,F vehicles decide not to broadcast the message, none of the cars behind them, will not receive the warning.this approach sometimes, called (Gossip-based flooding) (Bae, 20). 980

3 Intl. Res. J. Appl. Basic. Sci. Vol., 7 (3), , 203 opposite of the p-persistence method or gossip-based, weighted p-persistence devote a high probability to nodes that are away from spreader given that, GPS information is available from packet, header information. After receiving a packet from node i, node j check packet ID and relay the packet with P i,j probability, if receive that packet for first time. Otherwise, it drops that packet. According to relative distance between node I and j by D i,j and the average transmission rage R, the probability of relay P i,j, can be calculated based on each packet, using the following simple expression (Rezaei, 2009; Bae, 20) : Efficient - directional broadcast algorithm Lee et al. proposed a new broadcasting protocol called Efficient-Directional Broadcast for urban VANET with directional antennas. When a vehicle broadcast in roads, only the farthest receiver has duty to relay Message in the opposite direction that packet has receive from that direct.due to the topology of VANET networks that rapidly are changing, EDB decide based on receivers. So that relay packets by using GPS information. Remote receiver only has duty to send packets in the opposite direction which packet arrives, after that one vehicle received a information packet successfully, before decide to relay or not to relay waits long. During this time, the vehicle listens to other relay of the same packet.the waiting time can be calculated using the following formula (Li et al., 2007; Bae, 20) : In this formula, D is the distance from the locationtransmission information that is placed in packet, and R is the transmission rage (Li et al., 2007; Bae, 20). The downside of this method is that the vehicle propagates data only to the cars that are in the opposite direct of receiving packet. So, this work causes reducing the velocity of data publication. CBE-Cast algorithm This algorithm consists of two phases: set up phases and steady-state phase, which the two phases will describe in more detail (Deljavan Ghodrati and Mohammadkhanli, 203). Set up phase: each car which crash, create cluster, in its radio-range radius. The vehicle that has accident is considered as the base station. Warning message send to all of cluster members by the base station. Nodes within the cluster that received this message send a response message contains the velocity, ID and direction of vehicle movement. Base station divides vehicles into two categories based on moving direction, and for each category select a car as the head cluster, which is faster (Deljavan Ghodrati and Mohammadkhanli, 203). Steady-state phase: After setting of the head clusters at setup-phase, begin to relay the warning messages.to speed up in the message broadcasting operations determine new head clusters.this phase consists of several stages and at each step a new head cluster elected. Relay number, by present head cluster continues until determination of the next head cluster, so it may, number of relays, vary in each period (Deljavan Ghodrati and Mohammadkhanli, 203). PROPOSED METHOD INTRODUCTION This essay presents a new algorithm for messages broadcasting which proposed to cover the weaknesses of previous method. In the simple broadcasting method, we always face a lot of duplicate messages that can cause broadcast storm.in this cars we will face the interference phenomenon which this phenomenon causes relay of messages. P-persistence algorithm although, help to reduce broadcasting storm but don ' t prevent broadcasting storm with a hundred percent (00%), and just reduce the probability and chance of broadcasting storm. We face the delaying problem in EDB algorithm which this problem don ' t accepted for Real-time applications, and in the VANET networks, whatever the speed of sending and receiving message be high, it is better and acceptable. CBE-cast method that has been proposed to alleviate the broadcasting storm, for unilateral roads, don thave good performance in term of delay and packet collisions. The proposed method is called CBE-B (Cluster-Based Efficient Broadcast) which has great performance and has better performance in terms of broadcasting speed and 98

4 Intl. Res. J. Appl. Basic. Sci. Vol., 7 (3), , 203 propagation rate thanother methods, and prevent broadcasting storm in VANET networks. In the following figure, example of road and sight scenario of proposed algorithm is shown in figure 2. In the proposed algorithm, all vehicles are equipped with GPS receivers and aware of their position. Also the road considered unilateral. The algorithm runs on unilateral streets.when an accident accurse, vehicle involving accident, broadcast a message consists of vehicle ID and the position of the vehicle involving accident in transmission range. Massage (Vehicle ID, Location) Figure 2. Shows examples of the road scenari Presentation The proposed algorithm consists of two phases, setup phase and steady-state phase, which these phases will describe in more details. figure 3. Flowchart of Setup phase Setup Phase The car involving accident, causing the cluster to its radio range radius.we considered the vehicle involving accident, as the base station.warning message send to all nodes of cluster members by the base station. The 982

5 Intl. Res. J. Appl. Basic. Sci. Vol., 7 (3), , 203 nodes whitin the cluster that received this message, send a message to the base station. This response message contains the speed, id and direction of vehicle movement. Base station divided the vehicles based on their location, into two categories: Cars that are located behind the car involving accident stand in one category and the cars that located in front of the car involving accident stand in a cluster. For each cluster a headcluster selected as follows.in the cluster that located behind the car involving accident, the car which is slower selected as the headcluster. In the cluster that located in front of the car involving accident, the car which is faster selected as the headcluster.the flowchart of this phase of algorithm is shown in figure 3. Steady-state phase After that the headclusters set in the setup step, they started to relay the warning messages.to speed up in message broadcasting operation, new headclusters are determined. This phase consists of several courses. In each course a new head cluster selected. The number of relays by current headcluster continued until the next headcluster, selected. So, it may the number of relays vary in each course.in this phase, selection of headcluster performed in a distributed manner and this selection done according to the following rules..node that is farthest to the current headcluster, selected in high probability as the next headcluster and this probability calculate as follows P i,j = D i,j /R 2. The node that movement speed is high in it, selected as the front headcluster with a high probability. 3. The node that movement speed is slower in it, selected as the behind headcluster with a high probability. 4. The node which receive less warning message, selected as the next headcluster with a high probability. The pseudo-code of steady-state is shown in figure 4. Function_ClusterHead() { Broadcast Alert_MSG to member nodes; Wait Receive ACK_MSGs (ID, V,Loc, MSG_No) From member nodes; If (CH is front of accident point) For (i=;i<=size (Cluster_Mems);i++){ Calc P i =D i /R; Result i P i * V i * / MSG_No i ; } Else if (CH is rear of accident point) For (j=;j<=size(cluster_mems);j++){ Calc P j =D j /R; Result j V j /(MSG_No j* P j ); } Create Table_Vehi; If (CH is front of accident point){ Return Max { Result i } Next_CH Veh i } Else if(ch is rear of accident point){ Return Min {Resultj} Next_CH Veh j } } Figure 4. Pseudo-Code of steady-state phase Steady-state phase there is two state, nodes that are located in front of the accident point (front) and nodes that are located on the back of a car accident point (rear). In both of the states headcluster broadcast the warning 983

6 Intl. Res. J. Appl. Basic. Sci. Vol., 7 (3), , 203 message and response message consists of node attribute (ID ). Node speed ( v), node location (Loc ) and the receive number of warning message from the member nodes. We calculate a benchmark as a Result for each member of group. In calculating the Result benchmark, three factors involved which are: distance from the relay node, the node speed, and the receive number of warning message. After obtaining the above information, the current headclusters node represents a tabular form as Table_Veh i, which this example is shown in Table and Table 2. In the front cluster, the node selected as the headcluster which has more result and in the cluster which is rear, the node which has the lower result selected as the cluster head. Finally, by using the results of this table, current headcluster decide which of the nodes in the Cluster_Mems to selected as the next cluster head. Table. Front Cluster_Mems V Loc Pi,j MSG_No. Result Veh 90 (x,y ).0 90 Veh 2 20 (x 2,y 2) Veh 3 70 (x 3,y 3) In the Table although the second vehicle was faster but due to the proximity to the current headcluster, do not select as the next head cluster.also, the first car that is faster and farthest than other cars, selected as the front headcluster.according to the above table, the car Veh, which the maximum results that related to it, selected as the next headcluster. Table 2. Rear Cluster_Mems V Loc Pi,j MSG_No. Result Veh 90 (x,y ).0 90 Veh 2 20 (x 2,y 2) Veh 3 70 (x 3,y 3) In the Table 2 the node that has the lower speed and is far from the headcluster node selected as the head cluster. Thus, according to Table 2, veh 3 that has the lower result selected as the rear headcluster.in the rear table, the idea is that, the node selected as the head cluster that has the lower speed so that the network ' s delay reduce. Because, if a node that is faster selected, delay time increase. Simulation and performance evaluation Simulation Environment Simulation has done on the ubunto Linux operation system and by using network simulator NS3. Evaluation has done in a virtual environment.road length considered 0km and thenumber of vehicles is 00 nodes. Transmission radio rang considered 300m. The time between broadcastings is 3 seconds and road is 3 line and unilateral. Vehicles speed is between 55 to 00 kilometers per hour. Experiment is done by CBE-Cast, EDB, P-persistence, simple, and CBE-B proposed algorithm. SIMULATION RESULTS One of the broadcasting algorithm evaluation criteria in VANET network is collision rate of broadcasted warning packets. The figure 5 show the number of collision warning messages in the simulation area. The result of simulation in figure 5 shows the lowest collision rat for proposed method with compared other methods. Because in the proposed method just the node that selected as the head cluster which is allowed to relay the messages. This low rate of collision is due to the large reduction of the broadcasting storm in CBE-B algorithm. 984

7 Intl. Res. J. Appl. Basic. Sci. Vol., 7 (3), , simple p-persistence EDB CBE-Cast CBE-B figure 5. Compare collision rate of broadcasting rate of broadcast warning message Another important evaluation criterion of optimization of distributed algorithms in VANET networks is the success rate of delivery messages.in the proposed algorithms due to the lower rate of message relays and thus lower collision rate, the success rate is always full.in figure 6 the success rate of different publish methods and CBE-B proposed method is compared simple p-persistence EDB CBE-Cast CBE-B figure 6. Comparison of success rate in message delivery of warning The message propagation of delay time is important in VANET networks performance. Thus, in the proposed algorithm the delay time is less than CBE-cast algorithm. Figure 7, shows the delay of propagation with less nodes and figure 8 shows the delay of propagation with more density of nodes. 985

8 Intl. Res. J. Appl. Basic. Sci. Vol., 7 (3), , simple p-persistence EDB CBE-Cast CBE-B Figure 7. Latency in sparse networks simple p-persistence EDB CBE-Cast CBE-B Figure 8. Latency in dense networks In the Table 3, the improvement percent of presented idea is expressed as numeric. This percents contains the number of collisions, the success rate, delay time and the presentation of the proposed algorithms improvement percent in compared with CBE-B algorithm. Table 3. Improvement percent of CBE-B algorithm than other algorithms algorithm reduction in collisions success rate latency EDB % 0% % P-PERSISTANCE % +2.5% +46.9% SIMPLE % +2.3% +37.7% CBE-Cast -2.23% 0% -3.% 986

9 Intl. Res. J. Appl. Basic. Sci. Vol., 7 (3), , 203 CONCLUSION Since most application in VANET networks, unlike the point to point transmission, broadcast entirely.routing protocols should solve the broadcasting storm and prevent unnecessary loss of safety-related packets in the message publication. In the proposed algorithms called CBE-B which designed for one-way streets, created based on clustering and after setup phase, two cluster called front and rear created. In the front, the node which is faster selected as the head cluster. This method reduces the delay rate. In the next tasks we try to select the next head cluster based on phase. Theory it means that we give the speed, distance and number of warning messages measures as input to the phased system. Phased system choose the next optimized head cluster based on these criteria. REFERENCES Bae IH. 20. Design and Evaluation of a Hybrid Intelligent Broadcast Algorithm for Alert Message Dissemination in VANETs. International Journal of Grid and Distributed Computing Vol. 4, No. 4, December. Deljavan Ghodrati A, Mohammadkhanli L A New Cluster-Based Efficient Broadcast Algorithm for Alert Message Dissemination in VANETs. International Research Journal of Applied and Basic Sciences 203 Available online at ISSN X / Vol, 4 (5), Haas ZJ, Halpern JY, Li L Gossip-based Ad Hoc Routing. IEEE/ACM Transactions on Networking, vol.4, pp Li D, Huang H, Li X, Li M, Tang F A Distance-Based Directional Broadcast Protocol for Urban Vehicular Ad Hoc Network. International Conference on Wireless Communications, Networking and Mobile Computing, pp Rezaei F A Novel Data Dissemination Scheme in Vehicular Networks for Intelligent Transportation System Applications. A thesis presented to the University of Waterloo in fulfillment of the thesis requrirement for the degree of Master of Applied Science in Electrical and Computer Engineering, Waterloo, Ontario, Canada. Suriyapaibonwattana K, Pomavalai C An Effective Safety Alert Broadcast Algorithm for VANET", International Symposium on Communications and Information Technologies, pp Suriyapaibonwattana K, Pornavalai C, Chakraborty G An Adaptive Alert Message Dissemination Protocol for VANET to Improve Road Safety. In: FUZZ-IEEE, pp Sutariya D, Pradhan SN Data Dissemination Techniques in vehicular ad Hoc Network. International Journal of computer Applications, Vol.08-No.0, October. Tomar P, Chaurasia BK, Tomar GS State of the Art of Data Dissemination in VANETs. International Journal of computer Theory and Engineering, Vol.2, No.6, December. Tonguz OK, Wisitpongphan N, Parikh JS, Bai F, Mudalige P, Sadekar VK On the Broadcast Storm Problem in Ad hoc Wireless Networks. in: 3rd International Conference on Broadband Communications, Networks and Systems, pp. -. Tonguz OK, Wisitpongphan N, Parikht JS, Bait F On the Broadcast Storm Problem in Ad hoc Wireless Networks. IEEE. 987