Enhanced marking process (EMP) for constructing dominating set in mobile ad-hoc networks with unidirectional links

Broadcasting or flooding is one of the principal functions in wireless ad-hoc networks. In broadcasting, a mobile node sends the same message to all nodes in the network in one-to-all model. Broadcasting based on set of dominating nodes is remunerative approach, where the broadcasting activity is constrained to only the nodes in the dominating set. A set is dominating if all nodes in the network are either in the set or neighbors of nodes in the set. In this study, the notion of constructing connected-dominating-set is extended to ad-hoc networks with unidirectional links. An enhanced distributed algorithm is presented that is based on the marking process which is has been introduced in earlier work. Our enhanced algorithm features a good locality properties since it need only 2-hop neighborhood information within each node. The algorithm checks for the mutual existence of nodes in the neighbor table of their neighbors to guarantee the symmetric connectivity between neighboring nodes. The proposed algorithm is integrated with AODV routing protocol to generate a connected dominating set that will be responsible on flooding activity. The efficiency of our approach is investigated and verified through simulation whereas the computational complexity is determined and compared with that of original marking process. All the simulations run are carried out with QualNet Simulator version 5.02

A Performance Comparison of Virtual Backbone Formation Algorithms for Wireless Mesh Networks

Currently wireless networks are dominant by star topology paradigm. Its natural the evolution is towards wireless mesh multi-hop networks. This article compares the performance of several algorithms for virtual backbone formation in ad hoc mesh networks both theoretically and through simulations. Firstly, an overview of the algorithms is given. Next, the results of the algorithm simulations made with the program Dominating Set Simulation Suite (DSSS) are described and interpreted. We have been extended the simulator to simulate the Mobile Backbone Network Topology Synthesis Algorithm. The results show that this algorithm has the best combination of performance characteristics among the compared algorithms

Neighbour coverage: a dynamic probabilistic route discovery for mobile ad hoc networks

Blind flooding is extensively use in ad hoc routing protocols for on-demand route discovery, where a mobile node blindly rebroadcasts received route request (RREQ) packets until a route to a particular destination is established. This can potentially lead to high channel contention, causing redundant retransmissions and thus excessive packet collisions in the network. Such a phenomenon induces what is known as broadcast storm problem, which has been shown to greatly increase the network communication overhead and end-to-end delay. In this paper, we show that the deleterious impact of such a problem can be reduced if measures are taken during the dissemination of RREQ packets. We propose a generic probabilistic method for route discovery, that is simple to implement and can significantly reduce the overhead associated with the dissemination of RREQs. Our analysis reveals that equipping AODV with probabilistic route discovery can result in significant reduction of routing control overhead while achieving good throughput

A survey of flooding, gossip routing, and related schemes for wireless multi- hop networks

Flooding is an essential and critical service in computer networks that is used by many routing protocols to send packets from a source to all nodes in the network. As the packets are forwarded once by each receiving node, many copies of the same packet traverse the network which leads to high redundancy and unnecessary usage of the sparse capacity of the transmission medium. Gossip routing is a well-known approach to improve the flooding in wireless multi-hop networks. Each node has a forwarding probability p that is either statically per-configured or determined by information that is available at runtime, e.g, the node degree. When a packet is received, the node selects a random number r. If the number r is below p, the packet is forwarded and otherwise, in the most simple gossip routing protocol, dropped. With this approach the redundancy can be reduced while at the same time the reachability is preserved if the value of the parameter p (and others) is chosen with consideration of the network topology. This technical report gives an overview of the relevant publications in the research domain of gossip routing and gives an insight in the improvements that can be achieved. We discuss the simulation setups and results of gossip routing protocols as well as further improved flooding schemes. The three most important metrics in this application domain are elaborated: reachability, redundancy, and management overhead. The published studies used simulation environments for their research and thus the assumptions, models, and parameters of the simulations are discussed and the feasibility of an application for real world wireless networks are highlighted. Wireless mesh networks based on IEEE 802.11 are the focus of this survey but publications about other network types and technologies are also included. As percolation theory, epidemiological models, and delay tolerant networks are often referred as foundation, inspiration, or application of gossip routing in wireless networks, a brief introduction to each research domain is included and the applicability of the particular models for the gossip routing is discussed

Virtual backbone formation in wireless ad hoc networks

We study the problem of virtual backbone formation in wireless ad hoc networks. A virtual backbone provides a hierarchical infrastructure that can be used to address important challenges in ad hoc networking such as efficient routing, multicasting/broadcasting, activity-scheduling, and energy efficiency. Given a wireless ad hoc network with symmetric links represented by a unit disk graph G = (V, E ), one way to construct this backbone is by finding a Connected Dominating Set (CDS) in G , which is a subset V' ✹ V such that for every node u, u is either in V' or has a neighbor in V' and the subgraph induced by V' is connected. In a wireless ad hoc network with asymmetric links represented by a directed graph G = (V, E ), finding such a backbone translates to constructing a Strongly Connected Dominating and Absorbent Set (SCDAS) in G . An SCDAS is a subset of nodes V' ✹ V such that every node u is either in V' or has an outgoing and an incoming neighbor in V' , and the subgraph induced by V' is strongly connected. Based on most of its applications, minimizing the size of the virtual backbone is an important objective. Therefore, we are interested in constructing CDSs and SCDASs of minimal size. We give efficient distributed algorithms with linear time and message complexities for the construction of the CDS in ad hoc networks with symmetric links. Since topology changes are quite frequent in most ad hoc networks, we propose schemes to locally maintain the CDS in the face of such changes. We also give a distributed algorithm for the construction of the SCDAS in ad hoc networks with asymmetric links. Extensive simulations show that our algorithms outperform all previously known algorithms in terms of the size of the constructed sets

An Enhanced Algorithm to Find Dominating Set Nodes in Ad Hoc Wireless Networks

A wireless ad hoc network is a collection of wireless mobile nodes forming a temporary network without the aid of any established infrastructure or centralized administration. A connection is achieved between two nodes through a single hop transmission if they are directly connected or multi-hop transmission if they are not. The wireless networks face challenges to form an optimal routing protocol. Some approaches are based on a dominating set, which has all the nodes either in the set or within its neighborhood. The proposed algorithm is an enhancement of the distributed algorithm proposed by Wu and Li. The simulation results from the new algorithm are compared to results from Wu and Li’s algorithm. The simulation results show that the average dominating set of nodes decreased considerable after applying the new algorithm. The decrease in number of dominate set nodes is not very much noticeable in low density space

"Distributed routing schemes for ad hoc networks using d-SPR sets"

Michael Q. Rieck is an associate professor at Drake University in Des Moines, Iowa, USA. He holds a Ph. D. in mathematics from the University of South Florida. His primary research interests are in the areas of camera tracking and ad hoc wireless networks. He has also published results in the areas of triangle geometry, discrete mathematics, linear algebra, finite fields and association schemes.In this paper, we propose several new distributed algorithms for producing sets of nodes that can be used to form backbones of an ad hoc wireless network. Our focus is on producing small sets that are d-hop connected and d-dominating and have a desirable ‘d-shortest path property’ which we call d-SPR sets. These algorithms produce sets that are considerably smaller than those produced by an algorithm previously introduced by the authors. Our proposed algorithms, except the greedy ones, have constant time complexity in the restricted sense that the time required is unaffected by the size of the network, assuming however that the node degrees are bounded by a constant. The performance of the new algorithms are compared, and also compared with the authors' earlier algorithm, and with an adaptation of an algorithm of Wu and Li

Study on enhancement of dominating sets in Ad Hoc wireless networks

An essential component of effective use of Ad Hoc Wireless networks is proper utilization of available resources and network stability. There has been a recent increase of interest in Ad Hoc networks, partly due to the fact that Ad Hoc networks can be implemented without requiring any support from existing wired backbone or costly hardware setup. The effective utilization of the power of the Ad Hoc networks lies in scalability, stability, maintainability and rapid convergence of these networks. The route detection and route formation in the Ad Hoc networks should be done instantaneously. Performing effective route detection on such environments can be best achieved when the broadcasting is improved and the redundancy in route detection is removed. In this thesis work, a cluster based algorithm as well as a localized algorithm for Connected Dominating Set formation have been proposed. The Clustering algorithm forms disjoint logical groups of nodes with a lead node as head of the cluster. The cluster head takes part in the routing and has additional tasks of cluster maintenance. The clusters form a logical backbone and the Route search space is limited to the no. of clusters. But, the method forms suboptimal routes. The Connected Dominating Set based algorithm forms a logical backbone of connected gateways. The broadcast packets are retransmitted by these nodes. The routes are computed by shortest path algorithm. Changes in the backbone does not have impact on the ongoing communications. New routes are computed upon failure of existing routes. The results obtained using this algorithm are compared with other methods across a range of different scenarios with 100 nodes upon a simulation area of 100 X 100 twips. The Connected Dominating Set algorithm distributes the dominating nodes equally along the entire range while others are being biased towards higher “id” nodes. The Connected Dominating Set based algorithm is excelling the cluster algorithm in Search space size