Connected Dominating Set Research Articles

A Power Aware Minimum Connected Dominating Set for Wireless Sensor Networks

Connected Dominating Set (CDS) problem in unit disk graph has a significant impact on an efficient design of routing protocols in wireless sensor networks. In this paper, an algorithm is proposed for finding Minimum Connected Dominating Set (MCDS) using Dominating Set. Dominating Sets are connected by using Steiner tree. The algorithm goes through three phases. In first phase Dominating Sets are found, in second phase connectors are identified, connected through Steiner tree. In third phase the CDS obtained in second phase is pruned to obtain a MCDS. MCDS so constructed needs to adapt to the continual topology changes due to deactivation of a node due to exhaustion of battery power. These topological changes due to power constraints are taken care by a local repair algorithm that reconstructs the MCDS i.e. Power Aware MCDS, using only neighbourhood information. Simulation results indicate both the heuristics are very efficient and result in near optimal MCDS.

Evaluation of Physical Carrier Sense Based Backbone Maintenance in Mobile Ad Hoc Networks

Physical carrier sensing has to date mainly been exploited for improving medium access control in wireless networks. Recently, a parallel algorithm striving to extensively exploit physical carrier sensing for constructing and maintaining a connected dominating set (CDS), which is also known as spanner, backbone, or overlay network in wireless ad hoc networks with interference ranges larger than transmission ranges has been proposed. Existing evaluations of this algorithm are limited to theoretical asymptotic bounds and simulations of static networks. In this paper, we evaluate the physical carrier sensing-based CDS maintenance for mobile ad hoc networks through discrete event simulations. For a wide range of node speeds and node densities, we evaluate the CDS characteristics and message exchanges required for maintaining the CDS. We find that the algorithm maintains a stable leader set dominating all nodes in the network for a wide range of mobility levels but struggles to maintain connectivity at high mobility levels. We also quantify the portions of the control messages for CDS maintenance that are exchanged through physical carrier sensing. We find that the parallel algorithm manages to greatly reduce the reliance on intact message receptions.

A passive tree-based backbone construction scheme for MANETs

Backbone-based broadcast schemes are effective in alleviating the broadcast storm problem in mobile ad hoc networks (MANETs). However, periodically hello packets used to maintain a backbone usually lead to extra control overhead. In this paper, passive tree-based backbone construction scheme (PTBCS) is proposed as a backbone construction scheme for MANETs. Different from other schemes, each node in PTBCS determines its role by intercepting packet transmissions in the air during a special waiting period. Hence, its most remarkable advantage is that there are no periodical packet transmissions specially for backbone construction. The property that the nodes selected by PTBCS make up a connected dominating set (CDS) of the network is proven with several ideal assumptions. Simulation results show that PTBCS is effective when compared with some other typical backbone construction schemes.

Probabilistic analysis of upper bounds for 2-connected distance [formula omitted]-dominating sets in graphs

A small virtual backbone which is modeled as the minimum connected dominating set (CDS) problem has been proposed to alleviate the broadcasting storm for efficiency in wireless ad hoc networks. In this paper, we consider a general fault tolerant CDS problem, called an h -connected distance k -dominating set (HCKDS) to balance high efficiency and fault tolerance, and study the upper bound for HCKDS with a probabilistic method for small h and improve the current best results.

Rotation of CDS via Connected Domatic Partition in Ad Hoc Sensor Networks

Wireless ad hoc and sensor networks (WSNs) often require a connected dominating set (CDS) as the underlying virtual backbone for efficient routing. Nodes in a CDS have extra computation and communication load for their role as dominator, subjecting them to an early exhaustion of their battery. A simple mechanism to address this problem is to switch from one CDS to another fresh CDS, rotating the active CDS through a disjoint set of CDSs. This gives rise to the connected domatic partition (CDP) problem, which essentially involves partitioning the nodes V(G) of a graph G into node disjoint CDSs. We have developed a distributed algorithm for constructing the CDP using our maximal independent set (MlS)-based proximity heuristics, which depends only on connectivity information and does not rely on geographic or geometric information. We show that the size of a CDP that is identified by our algorithm is at least [delta+1/beta(c+1)] - f, where delta is the minimum node degree of G, beta les 2, c les 11 is a constant for a unit disk graph (UDG), and the expected value of f is epsidelta|V|, where epsi Lt 1 is a positive constant, and delta ges 48. Results of varied testing of our algorithm are positive even for a network of a large number of sensor nodes. Our scheme also performs better than other related techniques such as the ID-based scheme.

ANALYSIS ON THEORETICAL BOUNDS FOR APPROXIMATING DOMINATING SET PROBLEMS

Connected Dominating Set is widely used as virtual backbone in wireless networks to improve network performance and optimize routing protocols. Based on special characteristics of ad-hoc and sensor networks, we usually use unit disk graph to represent the corresponding geometrical structures, where each node has a unit transmission range and two nodes are said to be adjacent if the distance between them is less than 1. Since every Maximal Independent Set (MIS) is a dominating set and it is easy to construct, we can firstly find an MIS and then connect it into a Connected Dominating Set (CDS). Therefore, the ratio to compare the size of an MIS with a minimum CDS becomes a theoretical upper bound for approximation algorithms to compute CDS. In our paper, with the help of Voronoi diagram and Euler's formula, we improved this upper bound, so that improved the approximations based on this relation.

Constructing Minimum Connected Dominating Sets with Bounded Diameters in Wireless Networks

Connected Dominating Sets (CDSs) can serve as virtual backbones for wireless networks. A smaller virtual backbone incurs less maintenance overhead. Unfortunately, computing a minimum size CDS is NP-hard, and thus most researchers in this area concentrate on how to construct smaller CDSs. However, people neglected other important metrics of network, such as diameter and average hop distances between two communication parties. In this paper, we investigate the problem of constructing quality CDS in terms of size, diameter, and Average Backbone Path Length (ABPL). We present two centralized algorithms having constant performance ratios for its size and diameter of the constructed CDS. Especially, the size of CDS computed by the second algorithm is no more than 6.906 times of its optimal solution. Furthermore, we give its distributed version, which not only can be implemented in real situation easily but also considers energy to extend network lifetime. In our simulation, we show that in average the distributed algorithm not only generates a CDS with smaller diameter and ABPL than related work but also suppresses its size well. We also show that it is more energy efficient than others in prolonging network lifetime.

Multi-hop scatternet formation and routing for large scale Bluetooth networks

This paper addresses the scatternet formation for large scale multi-hop Bluetooth networks. We first describe an efficient method to build a Connected Dominating Set (CDS) as the backbone of multi-hop Bluetooth network, then propose new algorithms to form the dBBlue scatternets (Song et al., 2005) in each cluster. The final scatternet, M-dBBlue, guarantees the connectivity. Our experiment shows our scatternet seldom parks any node. We then propose a complete set of hierarchical routing methods for M-dBBlue which enables the self-routing inside each cluster. Moreover, our scatternet formation and routing algorithm do not necessarily require position information of the node.

An effective connected dominating set based mobility management algorithm in MANETs

This paper proposes a connected dominating set (CDS) based mobility management algorithm, CMMA, to solve the problems of node entering, exiting and movement in mobile ad hoc networks (MANETs), which ensures the connectivity and efficiency of the CDS. Compared with Wu’s algorithm, the proposed algorithm can make full use of present network conditions and involves fewer nodes. Also it has better performance with regard to the approximation factor, message complexity, and time complexity.

Bit-per-joule performance of power saving ad hoc networks with a mobile backbone

Energy efficient MAC protocols have been developed for wireless sensor and mobile ad hoc networks so that inactive nodes can transition into sleep state to conserve energy. It has been recognized that maintaining a continuously awake connected dominating set (CDS) serves to reduce the route setup latency. Under the mobile backbone network (MBN) architecture introduced by Rubin et al., a mobile backbone (Bnet) is dynamically constructed to provide a topological covering of the network. The MBN employs a hybrid routing algorithm under which flows that travel a distance longer than a threshold are directed along routes across the Bnet. In turn, a limited span network-wide global route discovery process is applied for routing shorter distance flows. In this paper, we introduce and analyze an MBN based power saving protocol (MBN-PS) that employs this hybrid routing scheme. Under the MBN-PS scheme, dynamically elected backbone nodes are kept awake, while inactive non-backbone nodes can reside in sleep state. We analytically show that, when the number of network flows is above a minimal level, the throughput per watt efficiency attained in an ad hoc network under complete backbone coverage is better than that achieved by a corresponding network that does not form a backbone. We present a model for the calculation of the bit-per-joule performance of the network as a function of the distance threshold. We confirm the validity of our analytical approach through simulations. Using our method, a network designer is able to choose the optimal distance threshold to be used by this scheme, based on traffic loading conditions.

Approximation hardness of dominating set problems in bounded degree graphs

We study approximation hardness of the Minimum Dominating Set problem and its variants in undirected and directed graphs. Using a similar result obtained by Trevisan for Minimum Set Cover we prove the first explicit approximation lower bounds for various kinds of domination problems (connected, total, independent) in bounded degree graphs. Asymptotically, for degree bound approaching infinity, these bounds almost match the known upper bounds. The results are applied to improve the lower bounds for other related problems such as Maximum Induced Matching and Maximum Leaf Spanning Tree.

Efficient algorithm for finding minimum connected dominating set in wireless sensor networks

The Connected Dominating Set(CDS)has been widely used for efficient routing in wireless sensor networks.Although finding the Minimum Connected Dominating Set(MCDS)in an arbitrary graph is a NP-hard problem,many approximation algorithms have been proposed to construct a serviceable CDS.To address the weaknesses of these existing algorithms,we proposed a new distributed approximation algorithm,CDS-HG,to construct the CDS for wireless sensor networks.This algorithm models a wireless sensor network as a hierarchical graph,in which a competition-based greedy strategy is used to select nodes at a certain level to route messages to the next level.Formal analysis and simulation studies show that our proposed CDS-HG algorithm generates the smallest CDS while requiring the least message complexity.

Zone-based virtual backbone formation in wireless ad hoc networks

Efficient protocol for clustering and backbone formation is one of the most important issues in wireless ad hoc networks. Connected dominating set (CDS) formation is a promising approach for constructing virtual backbone. However, finding the minimum CDS in an arbitrary graph is a NP-Hard problem. In this paper, we present a novel zone-based distributed algorithm for CDS formation in wireless ad hoc networks. In this Zone algorithm, we combine the zone and level concepts to sparsify the CDS constructed by previous well-known approaches. Therefore, this proposed algorithm can significantly reduce the CDS size. Particularly, we partition the wireless network into different zones, construct a dominating tree for each zone and connect adjacent zones by inserting additional connectors into the final CDS (at the zone borders). Our comprehensive simulation study using a custom simulator shows that this zone-based algorithm is more effective than previous approaches. The number of nodes in the CDS formed by this Zone algorithm is up to around 66% less than that constructed by others. Moreover, we also compare the performance of Zone algorithm with some recently proposed CDS formation protocols in ns2 simulator.

A fuzzy-based virtual backbone routing for large-scale MANETs

Virtual backbone-based routing is a promising approach for enhancing the routing efficiency in MANETs. To establish communication in the network, the virtual backbone nodes have to be connected. Connected Dominating Sets (CDS) are the earliest structures proposed as candidates for virtual backbones in Ad Hoc networks. In this paper, we propose a Fuzzy-based Virtual Backbone (FVB) routing scheme for large-scale mobile Ad Hoc networks that aims to maximise the network's lifetime. Each node in the network is characterised by its Residual Energy (RE), traffic and mobility. We develop a fuzzy logic controller that combines these parameters, keeping in mind the synergy between them. The value obtained indicates the importance of a node and it is used in network formation and maintenance. We compare our approach to another energy-efficient hierarchical protocol based on the Dominating Set (DS) idea. Our simulation shows that our design out performs the DS approach in prolonging the network lifetime.

Iterative Local Solutions for Connected Dominating Set in Ad Hoc Wireless Networks

In this paper, we propose a general framework of the iterative local solution (ILS) for computing a connected dominating set (CDS) in ad hoc wireless networks, which include mobile ad hoc networks (MANETS) and wireless sensor networks (WSNs). This approach uses an iterative application of a selected local solution. Each application of the local solution enhances the result obtained from the previous iteration, but each is based on a different node priority scheme. Then, we integrate this iterative process into the process for handling a dynamic network topology and propose two extensions: cyclic iterative local solution (CILS) and seamless iterative local solution (SILS). CILS offers a natural extension of ILS to the dynamic environment but suffers from a broken CDS and nonadaptiveness. With a novel use of a monotonically increasing sequence number for dynamic node priority, SILS offers an extension with the desirable properties of correctness, progressiveness, locality, and seamlessness. Extensive simulations are conducted under ns-2 and a custom simulator to evaluate the effectiveness of the proposed approach in both static and dynamic environments.

A novel distributed MCDS approximation algorithm for wireless sensor networks

AbstractSince finding the minimum connected dominating set (MCDS) in an arbitrary graph is a NP‐hard problem, many algorithms have been proposed to construct an approximation of the MCDS for efficient routing in wireless sensor networks (WSNs). To address the weaknesses of these existing algorithms, we propose a novel distributed MCDS approximation algorithm, CDS‐HG, to construct the connected dominating set (CDS) for WSNs. This algorithm models a WSN as a hierarchical graph and uses a competition‐based strategy to select nodes at a certain hierarchical level to route messages for nodes in the next level of the hierarchical graph. Formal analysis and simulation studies show that our CDS‐HG algorithm generates smaller CDS sizes while requiring less communication overhead compared with the existing distributed MCDS approximation algorithms. Copyright © 2007 John Wiley & Sons, Ltd.

Connected Dominating Sets in Wireless Networks with Different Transmission Ranges

Since there is no fixed infrastructure or centralized management in wireless ad hoc networks, a Connected Dominating Set (CDS) has been proposed to serve as a virtual backbone. The CDS of a graph representing a network has a significant impact on the efficient design of routing protocols in wireless networks. This problem has been studied extensively in Unit Disk Graphs (UDG), in which all nodes have the same transmission ranges. However, in practice, the transmission ranges of all nodes are not necessarily equal. In this paper, we model a network as a disk graph and introduce the CDS problem in disk graphs. We present two efficient approximation algorithms to obtain a minimum CDS. The performance ratio of these algorithms is constant if the ratio of the maximum transmission range over the minimum transmission range in the network is bounded. These algorithms can be implemented as distributed algorithms. Furthermore, we show a size relationship between a maximal independent set and a CDS as well as a bound of the maximum number of independent neighbors of a node in disk graphs. The theoretical analysis and simulation results are also presented to verify our approaches.

Analysis on a Localized Pruning Method for Connected Dominating Sets

While restricted rule-k has been succeeded in generating a connected dominating set (CDS) of small size, not much theoretical analysis on the size has been done. In this paper, an analysis on the expected size of a CDS generated by such algorithm and its relation to different node density is presented. Assume N nodes are deployed uniformly and randomly in a square of size L(subscript N)×L(subscript N) (where N and L(subscript N)→∞∞); three results are obtained. (1) It is proved that the node degree distribution of such a network follows a Poisson distribution. (2) The expected size of a CDS that is derived by the restricted pruning rule-k is a decreasing function with respect to the node density (The Symbol is abbreviated). For (The Symbol is abbreviated)≥30. it is found that the expected size is close to N/(The Symbol is abbreviated). (3) It is proved that the lower bound on the expected size of a CDS for a Poissonian network of node density (The Symbol is abbreviated) is given by (The equation is abbreviated)N. The second result is of paramount importance for practitioners. It provides the information about the expected size of a CDS when the node density (The Symbol is abbreviated) is between 6 and 30. The data (expected CDS size) for this range can hardly be provided by simulations.

Evaluation of distributed cover set algorithms in mobile ad hoc network for simplified multicast forwarding

This paper presents design issues and performance analysis of optimized cover set algorithms supporting Simplified Multicast Forwarding (SMF) of data plane traffic within mobile ad hoc network (MANET) environments. SMF is presently being developed within the Internet Engineering Task Force (IETF) as an experimental specification to provide simplified multicast data dissemination among multi-hop, wireless nodes within peer MANET routing neighborhoods. The SMF protocol allows for a variety of cover set reduction techniques to optimize the simplified data flooding and relaying process amongst routing peers. A variety of distributed algorithms for forming connected dominating sets (CDS) are being considered as mechanisms to reduce the cover set. This paper presents modeling and analysis work of various CDS relay set algorithms and demonstrates working code within an SMF implementation. We provide a brief problem background, discuss models and scenarios, compare various algorithms, and then summarize observations as well as discuss future work. A main purpose of the paper is to begin examining the robustness of the algorithms to mobility and increasing multicast traffic load. We examine the results against a classical flooding baseline for comparison. We observe similar efficiency and robustness performance for several forwarding algorithms of interest.

Fast distributed dominating set based routing in large scale MANETs

Hierarchical routing techniques have long been known to increase network scalability by constructing a virtual backbone. Even though MANETs have no physical backbone, a virtual backbone can be constructed by finding a connected dominating set (CDS) in the network graph. Many centralized as well as distributed algorithms have been designed to find a CDS in a graph (network). Theoretically, any centralized algorithm can be implemented in a distributed fashion, with the tradeoff of higher protocol overhead. Because centralized approaches do not scale well and because distributed approaches are more practical especially in MANETs, we propose a fast distributed connected dominating set (FDDS) construction in MANETs. FDDS has message and time complexity of O( n) and O( Δ 2), where n is the number of nodes in the network and Δ is the maximum node degree. According to our knowledge, FDDS achieves the best message and time complexity combinations among the previously suggested approaches. Moreover, FDDS constructs a reliable virtual backbone that takes into account (1) node’s limited energy, (2) node’s mobility, and (3) node’s traffic pattern. Our simulation study shows that FDDS achieves a very low network stretch. Also, when the network size is large, FDDS constructs a backbone with size smaller than other well known schemes found in the literature.