scholarly journals Plummeting Broadcast Storm Problem in Highways by Clustering Vehicles Using Dominating Set and Set Cover

Sensors ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 2191 ◽  
Author(s):  
S. Kamakshi ◽  
V. S. Shankar Sriram

“Vehicular Ad-hoc Networks” (VANETs): As an active research area in the field of wireless sensor networks, they ensure road safety by exchanging alert messages about unexpected events in a decentralized manner. One of the significant challenges in the design of an efficient dissemination protocol for VANETs is the broadcast storm problem, owing to the large number of rebroadcasts. A generic solution to prevent the broadcast storm problem is to cluster the vehicles based on topology, density, distance, speed, or location in such a manner that only a fewer number of vehicles will rebroadcast the alert message to the next group. However, the selection of cluster heads and gateways of the clusters are the key factors that need to be optimized in order to limit the number of rebroadcasts. Hence, to address the aforementioned issues, this paper presents a novel distributed algorithm CDS_SC: Connected Dominating Set and Set Cover for cluster formation that employs a dominating set to choose cluster heads and set covering to select cluster gateways. The CDS_SC is unique among state-of-the-art algorithms, as it relies on local neighborhood information and constructs clusters incrementally. Hence, the proposed method can be implemented in a distributed manner as an event-triggered protocol. Also, the stability of cluster formation is increased along with a reduction in rebroadcasting by allowing a cluster head to be passive when all its cluster members can receive the message from the gateway vehicles. The simulation was carried out in dense, average, and sparse traffic scenarios by varying the number of vehicles injected per second per lane. Besides, the speed of each individual vehicle in each scenario was varied to test the degree of cohesion between vehicles with different speeds. The simulation results confirmed that the proposed algorithm achieved 99% to 100% reachability of alert messages with only 6% to 10% of rebroadcasting vehicles in average and dense traffic scenarios.

Author(s):  
Hassan El Alami ◽  
Abdellah Najid

Energy efficiency and throughput are critical factors in the design routing protocols of WSNs. Many routing protocols based on clustering algorithm have been proposed. Current clustering algorithms often use cluster head selection and cluster formation to reduce energy consumption and maximize throughput in WSNs. In this chapter, the authors present a new routing protocol based on smart energy management and throughput maximization for clustered WSNs. The main objective of this protocol is to solve the constraint of closest sensors to the base station which consume relatively more energy in sensed information traffics, and also decrease workload on CHs. This approach divides network field into free area which contains the closest sensors to the base station that communicate directly with, and clustered area which contains the sensors that transmit data to the base station through cluster head. So due to the sensors that communicate directly to the base station, the load on cluster heads is decreased. Thus, the cluster heads consume less energy causing the increase of network lifetime.


2020 ◽  
Vol 34 (02) ◽  
pp. 1569-1576 ◽  
Author(s):  
Zhendong Lei ◽  
Shaowei Cai

The Set Covering Problem (SCP) and Dominating Set Problem (DSP) are NP-hard and have many real world applications. SCP and DSP can be encoded into Maximum Satisfiability (MaxSAT) naturally and the resulting instances share a special structure. In this paper, we develop an efficient local search solver for MaxSAT instances of this kind. Our algorithm contains three phrase: construction, local search and recovery. In construction phrase, we simplify the instance by three reduction rules and construct an initial solution by a greedy heuristic. The initial solution is improved during the local search phrase, which exploits the feature of such instances in the scoring function and the variable selection heuristic. Finally, the corresponding solution of original instance is recovered in the recovery phrase. Experiment results on a broad range of large scale instances of SCP and DSP show that our algorithm significantly outperforms state of the art solvers for SCP, DSP and MaxSAT.


2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Xiang Ji ◽  
Huiqun Yu ◽  
Guisheng Fan ◽  
Huaiying Sun ◽  
Liqiong Chen

Vehicular ad hoc network (VANET) is an emerging technology for the future intelligent transportation systems (ITSs). The current researches are intensely focusing on the problems of routing protocol reliability and scalability across the urban VANETs. Vehicle clustering is testified to be a promising approach to improve routing reliability and scalability by grouping vehicles together to serve as the foundation for ITS applications. However, some prominent characteristics, like high mobility and uneven spatial distribution of vehicles, may affect the clustering performance. Therefore, how to establish and maintain stable clusters has become a challenging problem in VANETs. This paper proposes a link reliability-based clustering algorithm (LRCA) to provide efficient and reliable data transmission in VANETs. Before clustering, a novel link lifetime-based (LLT-based) neighbor sampling strategy is put forward to filter out the redundant unstable neighbors. The proposed clustering scheme mainly composes of three parts: cluster head selection, cluster formation, and cluster maintenance. Furthermore, we propose a routing protocol of LRCA to serve the infotainment applications in VANET. To make routing decisions appropriate, we nominate special nodes at intersections to evaluate the network condition by assigning weights to the road segments. Routes with the lowest weights are then selected as the optimal data forwarding paths. We evaluate clustering stability and routing performance of the proposed approach by comparing with some existing schemes. The extensive simulation results show that our approach outperforms in both cluster stability and data transmission.


Wireless sensor networks(WSNs) finds wide applications in variousfields. The most important problem faced by these networksis low lifetime. These are generally battery powered devices withability to communicate with each other. Networks should be designedso that load is equally distributed among the nodes. In WSNs maximum load is on nodes being cluster heads, so for proper load distribution various nodes should get chance of becoming cluster head. Further entire network should have proper connectivity that is clusters should be evenly distributed throughout the network. To achieve this paper discusses algorithm to get dominating sets in a fully connected network.Dominating sets ensure that either a node is a cluster head or is adjacent to a cluster head. This leads to even distribution whichmay increase the lifespan of entire network. Not much attention has been given to even distribution of clusters.WSNs consists ofspatially distributed nodes over a target area with sensing and communication facility. Purpose of thesenodes is to study the entire area and communicate their observation to the central base station. This work presents an idea to form evenly distributed clusters. Even distribution in necessary for proper load sharing and prolonging the life of network. It needs much more emphasis than given to it. Further Ranking methodology has been discussed to rank the dominating sets based on certain parameters. This ranking methodology is used to determine which dominating set should become cluster heads ensuring even distribution.Ranking methodology comes into play if more than one dominating sets are obtained. These may be used where it is difficult for humans to physically visit on a regular basis. High lifetime of network ensures less physical presence of humans.


2021 ◽  
Author(s):  
Prophess Raj Kumar Nalluri ◽  
Josemin Bala Gnanadhas

Abstract In WSN-assisted IoT environment, the sensors are resource constrained. The energy, computing and storage resources of deployed sensors in the sensing area are limited. Clustering is the key method for saving energy in wireless sensor networks. A hybrid protocol named as an Energy Efficient Centroid-based Ant colony Optimization (EECAO) protocol is proposed in this paper to improve the performance of the sensor network in WSN-assisted IoT environments. The protocol uses the concept of centroid based clustering to gather the information of local clusters and ant colony optimization to relay that information to the base station. proposed hybrid protocol includes multiple clustering factors such as energy cost, channel consistency and cognitive sensor throughput to select cluster heads and a new distributed cluster formation for self-organizing deployed sensors. Selection of the super cluster head among the cluster heads is based on the energy centroid position for a defined coverage area. In EECAO protocol, the energy level of cognitive sensors is the key parameter for defining the position of centroid. To reduce the long-distance communication, path optimization between the super cluster heads and the base station is carried out using an ant routing model. Our simulation results indicate that EECAO protocol performs better when benchmarked against existing ETSP and EECRP protocols. The proposed hybrid protocol EECAO is well-suited for networks that requires long lifetime when the base station is placed at either center, border or outside the network.


2021 ◽  
Vol 11 (5) ◽  
pp. 2413
Author(s):  
Zahid Khan ◽  
Anis Koubaa ◽  
Sangsha Fang ◽  
Mi Young Lee ◽  
Khan Muhammad

The reliability, scalability, and stability of routing schemes are open challenges in highly evolving vehicular ad hoc networks (VANETs). Cluster-based routing is an efficient solution to cope with the dynamic and inconsistent structure of VANETs. In this paper, we propose a cluster-based routing scheme (hereinafter referred to as connectivity-based clustering), where link connectivity is used as a metric for cluster formation and cluster head (CH) selection. Link connectivity is a function of vehicle density and transmission range in the proposed connectivity-based clustering scheme. Moreover, we used a heuristic approach of spectral clustering for the optimal number of cluster formation. Lastly, an appropriate vehicle is selected as a CH based on the maximum Eigen-centrality score. The simulation results show that the suggested connectivity-based clustering scheme performs well in the optimal number of cluster selections, strongly connected (STC) route selection, and route request messages (RRMs) in the discovery of a particular path to the destination. Thus, we conclude that link connectivity and the heuristic approach of spectral clustering are valuable additions to existing routing schemes for high evolving networks.


2021 ◽  
Author(s):  
Ahmed Jawad Kadhim

Abstract Vehicular Ad hoc Network (VANET) refers to wireless connection of a large number of moving and stopped cars to transfer some knowledge about some events (e.g. accident, traffic jam, weather condition, etc.) to the passengers and drivers. The mobility of vehicles in unexpected directions destroys the network links and decreases the stability of the route between vehicles. This problem leads to repeat the routing discovery and maintenance operations and as a result increases the overhead and delay. Several classes of routing polices were proposed such as flat, hierarchical, cluster based, etc. Moreover, in the cluster based routing protocols, number of cluster head selection and cluster formation schemes have been suggested. Unfortunately, the stability of cluster heads and links was not satisfied. This paper aims to solve this problem by producing a new clustering formation technique. This technique selects the parked and stopped vehicles to work as cluster heads and gateway nodes with high stability. Moreover, a new cluster based routing protocol to build optimal paths with maximum stability and minimum delay called CRSD depending on optimization model is suggested. Several simulation scenarios with various mobility speeds and numbers of stopped and parked vehicles showed that CRDS is better than link reliability-based clustering approach (LRCA) and cluster-based VANET oriented evolving graph (CVoEG) according to network overhead, average end to end delay, path stability, and packet delivery ratio.


2013 ◽  
Vol 38 (1) ◽  
pp. 3-23 ◽  
Author(s):  
Ditipriya Sinha ◽  
Uma Bhattacharya ◽  
Rituparna Chaki

Abstract In this paper we propose a novel algorithm CLAR to build an agent based routing protocol using ACO technique in cluster based mobile ad-hoc networks. Clustering makes possible hierarchical routing in which paths are recorded between cluster-heads instead of nodes. This reduces routing overheads. Presence of an unstable and non-reliable cluster-head degrades the performance of the network since cluster-heads of the network take active role in routing messages between a source destination pair. The proposed algorithm chooses the most reliable and stable node as cluster-head depending on four criteria i.e.: stability, battery power, degree, and trust value of the node. It also uses a multiagent based routing algorithm to generate load balanced routes between source and destination in cluster-based network. Performance of CLAR is compared with other existing efficient algorithms such as AODV, CBRP, Wu & Li’s Algorithm, dominating set based clustering algorithms, agent-based algorithms named as SACO and MALBACO. Simulation results prove that the proposed protocol combines merits of both clustering approach and agent based approach and provides efficient packet delivery even in the presence of high load in the network


2020 ◽  
Vol 39 (6) ◽  
pp. 8357-8364
Author(s):  
Thompson Stephan ◽  
Ananthnarayan Rajappa ◽  
K.S. Sendhil Kumar ◽  
Shivang Gupta ◽  
Achyut Shankar ◽  
...  

Vehicular Ad Hoc Networks (VANETs) is the most growing research area in wireless communication and has been gaining significant attention over recent years due to its role in designing intelligent transportation systems. Wireless multi-hop forwarding in VANETs is challenging since the data has to be relayed as soon as possible through the intermediate vehicles from the source to destination. This paper proposes a modified fuzzy-based greedy routing protocol (MFGR) which is an enhanced version of fuzzy logic-based greedy routing protocol (FLGR). Our proposed protocol applies fuzzy logic for the selection of the next greedy forwarder to forward the data reliably towards the destination. Five parameters, namely distance, direction, speed, position, and trust have been used to evaluate the node’s stability using fuzzy logic. The simulation results demonstrate that the proposed MFGR scheme can achieve the best performance in terms of the highest packet delivery ratio (PDR) and minimizes the average number of hops among all protocols.


Author(s):  
Palky Mehta ◽  
H. L. Sharma

In the current scenario of Wireless Sensor Network (WSN), power consumption is the major issue associated with nodes in WSN. LEACH technique plays a vital role of clustering in WSN and reduces the energy usage effectively. But LEACH has its own limitation in order to search cluster head nodes which are randomly distributed over the network. In this paper, ERA-NFL- BA algorithm is being proposed for selects the cluster heads in WSN. This algorithm help in selection of cluster heads can freely transform from global search to local search. At the end, a comparison has been done with earlier researcher using protocol ERA-NFL, which clearly shown that proposed Algorithm is best suited and from comparison results that ERA-NFL-BA has given better performance.


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