Localized Topology Control Research Articles

Security-aware Localized Topology Control Algorithm for Mobile Ad-hoc Networks

In this paper, we extend the topology control schemes by making security the primary concern. For this purpose, we propose a security-aware localized topology control algorithm that can maximally avoid making malicious nodes into intermediate nodes. In order to marginalize malicious nodes, we introduce a new metric for characterizing the security status of each link in the network. Each node independently builds a local spanning tree for finding a reduced neighbor set. In the meantime, we maximally avoid using insecurity links in their neighborhood for the local spanning tree construction. Simulation results show that our algorithm significantly improves the security of a network.

Distributed Topology Control for Energy-Efficient and Reliable Wireless Communications

A dense wireless ad hoc network with a high average node degree offers a strong connectivity for packet routing, but at the same time increases the probability of interference between nodes and results in rapid depletion of node energy. To remedy this issue, topology control mechanisms aim at optimizing transmission power of nodes in a wireless ad hoc network to maintain the connectivity of the network, reduce the energy wastage, and increase the network throughput. In this paper, we propose a partially localized topology control algorithm, namely articulation points based topology control (APTC), which effectively saves power consumption in a wireless ad hoc network with a low communication overhead. Unlike the existing topology control protocols, APTC designates articulation points to be initiators and builds a tree of minimum spanning trees to achieve power saving while maintaining network connectivity. The simulation results demonstrate the superiority of APTC over the existing topology control algorithms in terms of power consumption and communication overhead.

Localized topology control and on-demand power-efficient routing for wireless ad hoc and sensor networks

Power use is a crucial design concern in wireless ad hoc and sensor networks since it corresponds directly to the network operational time. In this paper, we study the issue of power-efficient use in the following two aspects: Selecting power-efficient routes and performing efficient localized topology control to assign reduced transmit powers at nodes while preserving the global optimal connectivity. We proposed a localized topology control algorithm using two-hop neighborhood knowledge, which works to build local shortest path tree at each node independently in order to generate a reduced topology while preserving the global optimal connectivity. We derive the energy stretch ratio and maximum degree performance of our proposed algorithm as well as several existing algorithms in this aspect. We then devise three power-efficient on-demand routing protocols on top of various localized topology control algorithms, which are to acquire minimum-power paths while minimizing the associated protocol overhead for route discovery by utilizing local network state information and also packet receipt status at neighbor nodes. We further derive the asymptotical performance of the routing strategy in our protocols in terms of energy stretch ratio and route acquisition latency when network nodes operate at limited discrete power levels. Simulation results are provided to demonstrate the high performance of our topology control algorithm and also the devised routing protocols.

A Game-Based Localized Multi-Objective Topology Control Scheme in Heterogeneous Wireless Networks

In wireless networks, network topology may change at any time. Therefore, topology control is one of the effective methods to get and keep the desired topology performance. The most existing topology control methods assume that nodes are altruistic. Although there are some game-based topology control schemes to stimulate cooperation between nodes, they only consider a single objective (e.g., energy consumption or network lifetime), which cannot be adaptive to the variation of demand on topology performance. To address these weaknesses, we present the notion of link lifetime and model the multi-objective weight sum of any link as the function with respect to transmission power, link delay and link lifetime. Then the proposed game-based localized multi-objective topology control ensures that the desired topology property exists in resulting topology, in which the presented Improved LOCAL $\delta $ -Improvement Algorithm (LDIA) algorithm not only stimulates nodes’ cooperation on topology control operation and ensures network’s convergence to a steady state, but also has the better performance with respect to executing time and communication overhead than a classic algorithm, i.e., LDIA. Finally, the simulation results show that, by employing appropriate weight values, when compared with some typical schemes considering only energy efficiency, the proposed scheme is the most efficient in regard to average link delay and link lifetime. When compared with a typical scheme considering only network lifetime, the proposed scheme has advantage over average link lifetime, but it is slightly worse in terms of average link delay. Although the proposed scheme is less efficient in terms of average transmission power, where the shortage may be alleviated by adjusting weight values, it satisfies diversified demands for applications due to its flexibility.

A Topology Control and Routing Method in MCRNs Based on Power Consumption and Link Stability

In this paper, we study topology control and routing issues in mobile cognitive radio networks and propose local cognitive topology control algorithm (LCTCA) to provide the optimal network topology for routing. LCTCA combines link availability with link power consumption to form a multiobjective metric of network topology and routing optimization. The link availability prediction is aware of the interference from secondary users to primary users, the spectrum utilization of primary users, the mobility of secondary users and primary users. Based on the link availability and the power consumption, LCTCA captures the dynamic changes of the topology and constructs a reliable topology under the conditions of network connectivity, which is aimed at selecting the optimal network path and mitigating frequently rerouting. We further analyze the effect of power consumption and link stability on cognitive radio network path selection. Simulation investigation is also provided to verify the theoretical analysis. It shows that the link power consumption and the link stability are both important when selecting the network path.

Flexible Adjustments Between Energy and Capacity for Topology Control in Heterogeneous Wireless Multi-hop Networks

Topology Control is one of the most important techniques used in wireless multi-hop networks to obtain the desired network property. The most conventional MST-based topology control schemes both achieve a very good performance in terms of transmission power and implicitly consider network capacity, but they hardly have flexibility in determining whether more importance is placed on network capacity or not. Therefore, we jointly consider network capacity and energy efficiency in this paper. A new localized topology control scheme is proposed to meet the above two competing objectives by finding a balance between them through using Get_min-cost_for_link_(). The simulation results show that, when compared with some typical MST-based schemes, the proposed scheme can achieve the desired performance in terms of network capacity under the appropriate combination of weight values though it has a slightly worse performance in terms of transmission power. Moreover, the proposed scheme achieves the most balanced distribution with respect to path capacity among the compared schemes, especially when both k-hop neighborhood size and network node density increase. More importantly, the proposed scheme can flexibly determine that either network capacity or energy consumption should be given more attention according to the demand of the network application.

Foundation of Reactive Local Topology Control

We formalize the concept reactive (aka contention-based or beaconless) topology control and its underlying problem statement. By means of message complexity, we define the classes of O(k)- and Ω(k)-reactive topology control algorithms which allow us to distinguish reactive from conventional local approaches and to classify the former. Moreover, based on our formalisms we prove two fundamental propositions regarding the reactive computability of standard topology control structures. Thus, our contribution not only establishes a taxonomy for identification of research gaps, but constitutes a theoretical foundation for profound investigation of this algorithm classes' principal power.

Joint network lifetime and delay optimization for topology control in heterogeneous wireless multi-hop networks

The network lifetime maximization and the end-to-end delay minimization are tackled by jointly considering the two topology performance indexes in wireless multi-hop networks. Based on the existing eligibility metric for energy efficiency, as well as the new defined metrics for fair energy consumption and end-to-end delay, a new eligibility metric is modeled as ψtup (or ψtdown). From a node’s view point, the estimation over the neighboring nodes is made according to their ψtup (or ψtdown). The Lifetime and Delay based localized Topology Control (LDTC) algorithm is proposed to construct the topology, in which each node keeps its k physical neighbors with maximum ψtup (or ψtdown) as its logical neighbors. Then the Distributed Topology Symmetry (DTS) algorithm is proposed to enforce topology symmetry. Finally, we present the Distributed Logical Neighbor Adjustment (DLNA) algorithm, by which each node adjusts its logical neighbors during the interval between two successive executions of the LDTC and DTS algorithm in order to have nodes exhaust their energy fairly. The simulation results confirm that, under the most simulation settings, our topology control scheme has the minimized imbalance energy reserve and end-to-end delay when compared with the existing similar works. These results show that our topology control scheme suits to prolong the lifetime of the network and also satisfies the demand for low end-to-end delay.

An energy efficient localized topology control algorithm for wireless multihop networks

Localized topology control is attractive for obtaining reduced network graphs with desirable features such as sparser connectivity and reduced transmit powers. In this paper, we focus on studying how to prolong network lifetime in the context of localized topology control for wireless multi-hop networks. For this purpose, we propose an energy efficient localized topology control algorithm. In our algorithm, each node is required to maintain its one-hop neighborhood topology. In order to achieve long network lifetime, we introduce a new metric for characterizing the energy criticality status of each link in the network. Each node independently builds a local energy-efficient spanning tree for finding a reduced neighbor set while maximally avoiding using energy-critical links in its neighborhood for the local spanning tree construction. We present the detailed design description of our algorithm. The computational complexity of the proposed algorithm is deduced to be O(mlog n), where m and n represent the number of links and nodes in a node's one-hop neighborhood, respectively. Simulation results show that our algorithm significantly outperforms existing work in terms of network lifetime.

On Minimizing the Impact of Mobility on Topology Control in Mobile Ad Hoc Networks

Although topology control has received much attention in stationary sensor networks by effectively minimizing energy consumption, reducing interference, and shortening end-to-end delay, the transience of mobile nodes in Mobile Ad hoc Networks (MANETs) renders topology control a great challenge. To circumvent the transitory nature of mobile nodes, k-edge connected topology control algorithms have been proposed to construct robust topologies for mobile networks. However, uniformly using the value of k for localized topology control algorithms in any local graph is not effective because nodes move at different speeds. Moreover, the existing k-edge connected topology control algorithms need to determine the value of k a priori, but moving speeds of nodes are unpredictable, and therefore, these algorithms are not practical in MANETs. A dynamic method is proposed in this paper to effectively employ k-edge connected topology control algorithms in MANETs. The proposed method automatically determines the appropriate value of k for each local graph based on local information while ensuring the required connectivity ratio of the whole network. The results show that the dynamic method can enhance the practicality and scalability of existing k-edge connected topology control algorithms while guaranteeing the network connectivity.

Localized Topology Control for Minimizing Interference under Physical Model

During last few years, research communities paid much attention to interference in wireless sensor network, lots of work has been done. However, all of those approaches suffer from some kind of defects. Inspired by the unsolved problems, we propose a definition of interference, which considering interference under physical model, meanwhile, can be determined by static model and localized information without introducing computation burden on nodes.

Adaptive Physical Carrier Sense in Topology-Controlled Wireless Networks

Transmit power and carrier sense threshold are key MAC/PHY parameters in carrier sense multiple access (CSMA) wireless networks. Transmit power control has been extensively studied in the context of topology control. However, the effect of carrier sense threshold on topology control has not been properly investigated in spite of its crucial role. Our key motivation is that the performance of a topology-controlled network may become worse than that of a network without any topology control unless carrier sense threshold is properly chosen. In order to remedy this deficiency of conventional topology control, we present a framework on how to incorporate physical carrier sense into topology control. We identify that joint control of transmit power and carrier sense threshold can be efficiently divided into topology control and carrier sense adaptation. We devise a distributed carrier sense update algorithm (DCUA), by which each node drives its carrier sense threshold toward a desirable operating point in a fully distributed manner. We derive a sufficient condition for the convergence of DCUA. To demonstrate the utility of integrating physical carrier sense into topology control, we equip a localized topology control algorithm, LMST, with the capability of DCUA. Simulation studies show that LMST-DCUA significantly outperforms LMST and the standard CSMA protocol.

Variable radii connected sensor cover in sensor networks

One of the useful approaches to exploit redundancy in a sensor network is to keep active only a small subset of sensors that are sufficient to cover the region required to be monitored. The set of active sensors should also form a connected communication graph, so that they can autonomously respond to application queries and/or tasks. Such a set of active sensors is known as a connected sensor cover, and the problem of selecting a minimum connected sensor cover has been well studied when the transmission radius and sensing radius of each sensor is fixed. In this article, we address the problem of selecting a minimum energy-cost connected sensor cover, when each sensor node can vary its sensing and transmission radius; larger sensing or transmission radius entails higher energy cost. For the aforesaid problem, we design various centralized and distributed algorithms, and compare their performance through extensive experiments. One of the designed centralized algorithms (called CGA) is shown to perform within an O (log n ) factor of the optimal solution, where n is the size of the network. We have also designed a localized algorithm based on Voronoi diagrams which is empirically shown to perform very close to CGA and, due to its communication-efficiency, results in significantly prolonging the network lifetime. We also extend the aforementioned algorithms to incorporate fault tolerance. In particular, we show how to extend the algorithms to address the minimum energy-cost connected sensor k -cover problem, in which every point in the query region needs to be covered by at least k distinct active sensors. The CGA preserves the approximation bound in this case. We also propose a localized topology control scheme to preserve k -connectivity, and use it to extend the Voronoi-based approach to computing a minimum energy-cost k 1 -connected k 2 -cover. We study the performance of our proposed algorithms through extensive simulations.

An energy-efficient localized topology control algorithm for wireless ad hoc and sensor networks

Topology control plays an important role in the design of wireless ad hoc and sensor networks and has demonstrated its high capability in constructing networks with desirable characteristics such a...

An energy‐efficient localized topology control algorithm for wireless ad hoc and sensor networks

AbstractTopology control plays an important role in the design of wireless ad hoc and sensor networks and has demonstrated its high capability in constructing networks with desirable characteristics such as sparser connectivity, lower transmission power, and smaller node degree. However, the enforcement of a topology control algorithm in a network may degrade the energy‐draining balancing capability of the network and thus reduce the network operational lifetime. For this reason, it is important to take into account energy efficiency in the design of a topology control algorithm in order to achieve prolonged network lifetime. In this paper, we propose a localized energy‐efficient topology control algorithm for wireless ad hoc and sensor networks with power control capability in network nodes. To achieve prolonged network lifetime, we introduce a concept called energy criticality avoidance and propose an energy criticality avoidance strategy in topology control and energy‐efficient routing. Through theoretical analysis and simulation results, we prove that the proposed topology control algorithm can maintain the global network connectivity with low complexity and can significantly prolong the lifetime of a multi‐hop wireless network as compared with existing topology control algorithms with little additional protocol overhead. Copyright © 2008 John Wiley & Sons, Ltd.

Mobility-sensitive topology control in mobile ad hoc networks

In most existing localized topology control protocols for mobile ad hoc networks (MANETs), each node selects a few logical neighbors based on location information and uses a small transmission range to cover those logical neighbors. Transmission range reduction conserves energy and bandwidth consumption, while still maintaining network connectivity. However, the majority of these approaches assume a static network without mobility. In a mobile environment network connectivity can be compromised by two types of "bad" location information: inconsistent information, which makes a node select too few logical neighbors, and outdated information, which makes a node use too small a transmission range. In this paper, we first show some issues in existing topology control. Then, we propose a mobility-sensitive topology control method that extends many existing mobility-insensitive protocols. Two mechanisms are introduced: consistent local views that avoid inconsistent information and delay and mobility management that tolerate outdated information. The effectiveness of the proposed approach is confirmed through an extensive simulation study

A scalable, power-efficient broadcast algorithm for wireless networks

Scalability and power-efficiency are two of the most important design challenges in wireless ad hoc networks. In this paper, we present a scalable, power-efficient broadcast algorithm for wireless ad hoc networks. We first investigate the trade-off between (i) reaching more nodes in a single hop using higher transmission power and (ii) reaching fewer nodes using lower transmission power and relaying messages through multiple hops. Our analysis indicates that multi-hop broadcast is more power-efficient if α ≥ 2.2, where α is the path loss exponent in the power consumption model P(r, α) = c0 ċ rα + c1. Based on the analysis, we then propose Broadcast over Local Spanning Subgraph (BLSS). In BLSS, an underlying topology is first constructed by a localized topology control algorithm, Fault-Tolerant Local Spanning Subgraph (FLSS). FLSS can preserve k- connectivity of the network, where the value of k determines the degree of fault tolerance. Broadcast messages are then simply relayed through the derived topology in a constrained flooding fashion. BLSS is fully localized, scalable, power-efficient, and fault-tolerant. Simulation results show that the performance of BLSS is comparable to that of centralized algorithms.

Localized topology control for unicast and broadcast in wireless ad hoc networks

We propose a novel localized topology-control algorithm for each wireless node to locally select communication neighbors and adjust its transmission power accordingly such that all nodes together self-form a topology that is energy efficient simultaneously for both unicast and broadcast communications. We theoretically prove that the proposed topology is planar, which meets the requirement of certain localized routing methods to guarantee packet delivery; it is power-efficient for unicast - the energy needed to connect any pair of nodes is within a small constant factor of the minimum; it is also asymptotically optimum for broadcast - the energy consumption for broadcasting data on top of it is asymptotically the best among all structures constructed using only local information; it has a constant bounded logical degree, which will potentially save the cost of updating routing tables if used. We further prove that the expected average physical degree of all nodes is a small constant. To the best of our knowledge, this is the first localized topology-control strategy for all nodes to maintain a structure with all these desirable properties. Previously, only a centralized algorithm was reported. Moreover, by assuming that the node ID and its position can be represented in O(log n) bits for a wireless network of n nodes, the total number of messages by our methods is in the range of theoretical results are corroborated in the simulations.

Localized topology control for heterogeneous wireless sensor networks

This article studies topology control in heterogeneous wireless sensor networks, where different wireless sensors may have different maximum transmission ranges and two nodes can communicate directly with each other if and only if they are within the maximum transmission range of each other. We present several localized topology control strategies in which every wireless sensor maintains logical communication links to only a selected small subset of its physical neighbors using information of sensors within its local neighborhood in a heterogeneous network environment. We prove that the global logical network topologies formed by these locally selected links are sparse and/or power efficient and our methods are communication efficient. Here a structure is power efficient if the total power consumption of the least cost path connecting any two nodes in it is no more than a small constant factor of that in the original heterogeneous communication network. By utilizing the wireless broadcast channel capability, and assuming that a message sent by a sensor node will be received by all sensors within its transmission region with at most a constant number of transmissions, we prove that all our methods use at most O(n) total messages, where each message has O (log n ) bits. We also conduct extensive simulations to study the practical performance of our methods.

Localized topology control algorithms for heterogeneous wireless networks

Most existing topology control algorithms assume homogeneous wireless networks with uniform maximal transmission power, and cannot be directly applied to heterogeneous wireless networks where the maximal transmission power of each node may be different. We present two localized topology control algorithms for heterogeneous networks: Directed Relative Neighborhood Graph (DRNG) and Directed Local Spanning Subgraph (DLSS). In both algorithms, each node independently builds its neighbor set by adjusting the transmission power, and defines the network topology by using only local information. We prove that: 1) both DRNG and DLSS can preserve network connectivity; 2) the out-degree of any node in the resulting topology generated by DRNG or DLSS is bounded by a constant; and 3) DRNG and DLSS can preserve network bi-directionality. Simulation results indicate that DRNG and DLSS significantly outperform existing topology control algorithms for heterogeneous networks in several aspects.