Backbone Nodes Research Articles

Finding minimum weight connected dominating set in stochastic graph based on learning automata

Finding the minimum weight connected dominating set (MCDS) in an arbitrary graph is an NP-hard problem and several heuristics and approximation methods have been proposed to solve it. Forwarding the messages along the virtual backbone induced by the connected dominating set (CDS) significantly reduces the routing overhead as well as the power consumption by reducing the routing nodes to the backbone nodes. This paper first defines the stochastic MCDS problem where the probability distribution function (PDF) of the random weight associated with the graph vertices is unknown. Then, it presents several learning automata-based algorithms (Algorithms 1–6) to solve the stochastic MCDS problem. Taking advantage of learning automata, the proposed algorithms significantly reduce the number of samples that must be taken from the graph to construct the MCDS. It is proved that by the proper choice of the learning rate, the probability of finding the MCDS is close enough to unity. The standard sampling method (SSM) is the baseline with which we compare the performance of the proposed algorithms. Experimental results show that Algorithm 6 significantly outperforms the SSM and the other proposed algorithms in terms of the sampling rate.

Adaptive neighbor-based topology control protocol for wireless multi-hop networks

Topology control protocols have been proposed to construct efficient network topologies with several design goals, e.g., network-wide connectivity, minimal energy cost, symmetry, lower nodal degree, and therefore higher spatial reuse or lower interferences. Neighbor-based topology control protocols are simple and assume that each node in the network is connected to its k least-distant neighbors. There have been several empirical and theoretical research efforts that recommend a network-wide optimal value of the local parameter k. However, since most of the design goals often run against each other the suggested lower and upper bounds on the values of k are not sufficient to provide a controllable trade-off among various design goals. In this article, an adaptive neighbor-based topology control protocol is presented where the neighboring nodes collaborate and provide feedback on the network connectivity to decide on their respective transmission ranges. Since every node adaptively adjusts its number of neighbors, the parameter k acts as a performance knob to choose a set of backbone nodes and to form a hierarchical topology structure consisting of symmetric links. Through extensive simulation-based study, it is shown that the value of k can be tuned to generate fully connected network topologies while offering an efficient trade-off among various design goals.

A Distributed Algorithm for Virtual Backbone Construction with Cellular Structure in WSNs

The normal node in wireless sensor networks (WSNs) often has no constant energy supply. To make efficient use of limited energy resources significant, a major way to save limited energy resources is constructing a smaller virtual backbone in WSNs. In this paper, we propose a distributed algorithm for virtual backbone construction with cellular structure in WSNs (DBC), which is an improvement of algorithm ABP (Duresi and Paruchuri, 2008) and minimize the distortion of constructed cellular structure by improving the way of calculating strategic points using 1-hop neighbor information. Our simulation results show that algorithm DBC has smaller virtual backbone than algorithm ABP, and the number of backbone nodes is much fewer than that one.

Limit laws for coverage in backbone-sensor networks

We study coverage in sensor networks having two types of nodes, namely, sensor nodes and backbone nodes. Each sensor is capable of transmitting information over relatively small distances. The backbone nodes collect information from the sensors. This information is processed and communicated over an ad hoc network formed by the backbone nodes, which are capable of transmitting over much larger distances. We consider two models of deployment for the sensor and backbone nodes. One is a Poisson–Poisson cluster model and the other a dependently thinned Poisson point process. We deduce limit laws for functionals of vacancy in both models using properties of association for random measures.

Optimization of Tree-like Core Overlay in Hybrid-structured Application-layer Multicast

The tree topology in multicast systems has high transmission efficiency, low latency, but poor resilience to node failures. In our work, some nodes are selected as backbone nodes to construct a tree-like core overlay. Backbone nodes are reliable enough and have strong upload capacity as well, which is helpful to overcome the shortcomings of tree topology. The core overlay is organized into a spanning tree while the whole overlay is of mesh-like topology. This paper focuses on improving the performance of the application-layer multicast overlay by optimizing the core overlay which is periodically adjusted with the proposed optimization algorithm. Our approach is to construct the overlay tree based on the out-degree weighted reliability where the reliability of a node is weighted by its upload bandwidth (out-degree). There is no illegal solution during the evolution which ensures the evolution efficiency. Simulation results show that the proposed approach greatly enhances the reliability of the tree-like core overlay systems and achieves shorter delay simultaneously. Its reliability performance is better than the reliability-first algorithm and its delay is very close to that of the degree-first algorithm. The complexity of the proposed algorithm is acceptable for application. Therefore the proposed approach is efficient for the topology optimization of a real multicast overlay.

Topographical Automation of MANET using Reactive Routing Protocols

Wireless mobile ad-hoc networks (MANET) are characterized as infrastructure less networks. Topologies are formed with movement of regular nodes which has multi radio links and these regular nodes under demand behaves as backbone node (router) to forward packets across the network. These networks suffer frequent topology changes due to the dynamic stochastic process behavior of incoming nodes. Mobile ad-hoc networks lack load balancing that causes unnecessary packet loss and route break up in real-time data transmission. Area of operation, interference, and communication link range and path loss are the factors to affect the throughput of MANET. In this paper we evaluated the performance of AODV and DSR routing protocols which are enhanced by an Automation Topography, In our proposed Topographical Automation the location of incoming nodes are completely random and those will be confined themselves within a certain communication range such that the throughput is enhanced to meet better QoS level. As location of the nodes are system defined and quite automatic, nodes before being forwarded with the full assurance of successful session flows. It is often advantageous to position stable and capable relay nodes, including unmanned ground vehicles (UGVs) or unmanned aerial vehicles (UAVs), and unmanned under sea vehicles (UUVs) used by Defense to save cost as well as life.

Node pacing for small optical RAM-buffered packet-switching networks

One of the difficulties with optical packet switched (OPS) networks is buffering optical packets in the network. The only available solution that can currently be used for buffering in the optical domain is using long fiber lines called fiber delay lines (FDLs), which have severe limitations. Moreover, the research on optical RAM presently being done is not expected to achieve a large capacity soon. However, the burstiness of Internet traffic causes high packet drop rates and low utilization in very small buffered OPS networks. We therefore propose a new node-based pacing algorithm for decreasing burstiness. We show that by applying some simple pacing at the edge or core backbone nodes, the performance of very small optical RAM buffered core OPS networks with variable-length packets can be notably increased.

군 전술망의 무선 이동 통신 체계의 통신 범위 중첩을 고려한 채널 할당 기법과 데이터 전달 기법

In this paper, we propose a channel allocation algorithm of MSAP(Mobile Subscriber Access Point) and data delivery scheme exploiting the symbol level network coding. The network is comprised of TS(Tactical Switch) as a backbone node, MSAPs, and TMFTs(Tactical Multi-Function Terminal). The TS performs the channel allocation considering the communication range overlapping between the neighboring MSAPs and applies the symbol level network coding, if necessary, depending on the position of the TMFTs. Assuming the number of available antennas of TMFT and MSAP will be extended to two from one, we propose two schemes: single mode and dual mode. Through the simulation, we show that the proposed delivery scheme provides higher delivery ratio and lower delivery delay compared with the legacy store-and-forward scheme.

이동 궤적을 고려한 링크 상태 예측을 통한 공중 백본 네트워크 라우팅 성능 향상 방법

The airborne backbone network(ABN) provides communication transport services between airborne nodes, surface nodes and satellite nodes. Such ABN is generally constructed with wide-body and high-capacity planes such as AWACS, which can fly long-term along pre-defined flight paths. In this paper, we propose an efficient method to improve routing performances by reconfiguring routing path before link failure based on the prediction of link state with the information of pre-defined backbone nodes' trajectories. Since the proposed method does not need additional information exchange between airborne nodes in order to acknowledge the link failure, it can be effectively used for airborne backbone network with limited bandwidths.

A Modified TopDisc Algorithm in WSN

TopDisc algorithm, one classic algorithm based on minimum dominating set, puts forward an effective method—approximate topology to set up network. TopDisc algorithm, which only needs local information, is a fully distributed and expandable network-control algorithm. The shortcomings of such algorithm are as follows: the algorithm expense is considerable without taking nodes residual energy into account. After a close analysis of TopDisc algorithm, the author proposes a modified algorithm. The modified algorithm makes good use of the nodes residual energy and reasonably chooses backbone node form heavily energy-loaded ones, which makes the energy evenly consumed, network topology stable and network lifetime endurable. Simulation data indicate that the modified algorithm is very flexible, making the energy evenly consumed, net work topology stable and network lifetime endurable.

Throughput Optimization in Mobile Backbone Networks

This paper describes new algorithms for throughput optimization in a mobile backbone network. This hierarchical communication framework combines mobile backbone nodes, which have superior mobility and communication capability, with regular nodes, which are constrained in mobility and communication capability. An important quantity of interest in mobile backbone networks is the number of regular nodes that can be successfully assigned to mobile backbone nodes at a given throughput level. This paper develops a novel technique for maximizing this quantity in networks of fixed regular nodes using mixed-integer linear programming (MILP). The MILP-based algorithm provides a significant reduction in computation time compared to existing methods and is computationally tractable for problems of moderate size. An approximation algorithm is also developed that is appropriate for large-scale problems. This paper presents a theoretical performance guarantee for the approximation algorithm and also demonstrates its empirical performance. Finally, the mobile backbone network problem is extended to include mobile regular nodes, and exact and approximate solution algorithms are presented for this extension.

GBG Approach for Connectivity and Coverage Control in Wireless Sensor Network

sensor network are used to monitor various physical environment. These environments are mostly highly asymmetric terrains. The deployment of the sensor node for coverage and connectivity cost should be optimized. Therefore, in sensor network, providing high connectivity and coverage becomes the critical issue. In the proposed work, coverage and connectivity is a minimization of cost function as square of the distance between the nodes. This has been solved for cost optimization which is based on gradient methods. This modified protocol provides a genetic framework. We assume that the backbone nodes are connected to each and they provide coverage to the sensors on the basis of fitness function. The protocol performing better on the basis of cost which is also optimizing both network coverage and backbone connectivity. Our formalization allows the design of self-organized network system, which achieves minimum cost configurations. We have presented simulation results that show the effectiveness of genetic algorithm to provide network configuration that optimize both network coverage and backbone connectivity in different scenarios. We have simulated the Genetic Based Gradient (GBG) method and the proposed work in done on MATLAB.

STAB-WIN: Self Organized, Topology Control Ability Backbone Node in Wireless Networks

The objective of the paper is to construct a backbone node with self organization, topology control and reconfiguration capabilities. The key issues in wireless networks are maintain a topology with minimum degree, self organization during link or node failure and reconstruction ability when the backbone changes the position. Existing research works concentrate on any one of the issues by a backbone, but nodes in wireless are battery operated. To solve the all issues separately more power is required. To overcome the existing issues we propose a localized approach namely STAB-WIN, which will solve all the issues without affecting the entire system performance using local updates. This research work focuses on multiservice ability of a node to meet the design goals of next generation networks. Our approach is witnessed by the simulation results on analyzing the parameters like scalability which includes backbone size, routing overhead, control transfer and QoS parameters.

End-to-end throughput improvement for single radio multi-channel multi-path wireless mesh networks: a cross layer design

The distinguished feature of fixed backbone nodes in the wireless mesh networks (WMNs) can be utilized to design an efficient cross layer which cooperates routing and scheduling schemes for increasing end-to-end throughput. With only single radio nodes, by well designing the scheduling and routing schemes for multiple paths, we show that WMN can gain more throughput and reduce communication interference. Much of recent work has focused on those issues applied for “multi-channel, multi-path” environment using multi-radios that is costly and much more complex for implementation. Also, almost all of the proposals work on layer 2 or layer 3 separately that cannot support each other in performing efficiently. Instead, our paper introduces a cross-layer design with new routing algorithm that can balance the numbers of multi-paths and the needed transmission data in each communication session. We also propose a new channel scheduling and queuing models in MAC layer compatible with routing scheme and define a threshold with an effective algorithm to choose the optimal number of disjoint paths for routing scheme. The simulation results show that our multi-path routing scheme performs better than previous proposals in term of throughput improvement which can directly reduce the time of each communication session, especially in case of big size data transmission.

MTreebone: A Collaborative Tree-Mesh Overlay Network for Multicast Video Streaming

Recently, application-layer overlay networks have been suggested as a promising solution for live video streaming over the Internet. To organize a multicast overlay, a natural structure is a tree, which, however, is known vulnerable to end-hosts dynamics. Data-driven approaches address this problem by employing a mesh structure, which enables data exchanges among multiple neighbors, and thus, greatly improves the overlay resilience. It unfortunately suffers from an efficiency-delay trade-off, because data have to be pulled from mesh neighbors by using extra notifications periodically. In this paper, we closely examine the contributions of overlay nodes, and argue that performance of a mesh overlay closely depends on a small set of stable backbone nodes. This is validated through a real trace study on PPLive, the largest commercial application-layer live streaming system to date. Motivated by this observation, we then suggest a novel collaborative tree-mesh design that leverages both mesh and tree structures. The key idea is to identify a set of stable nodes to construct a tree-based backbone, called treebone, with most of the data being pushed over this backbone. These stable nodes, together with others, are further organized through an auxiliary mesh overlay, which facilitates the treebone to accommodate node dynamics and fully exploit the available bandwidth between overlay nodes. This hybrid design, referred to as mTreebone, brings a series of unique and critical design challenges. In particular, the identification of stable nodes and seamless data delivery using both push and pull methods. In this paper, we present optimized solutions to these problems, which reconcile the two overlays under a coherent framework with controlled overhead. We evaluate mTreebone through both simulations and PlanetLab experiments. The results demonstrate the superior efficiency and robustness of this hybrid solution in both static and dynamic scenarios.

A Survey on Routing Protocols that really Exploit Wireless Mesh Network Features

The design of a routing protocol that really exploits the specific features of a Wireless Mesh Network (WMN) still remains a challenge. The expected additional benefit, with respect to those that do not or cannot exploit them, is an increase in overall throughput supported by the network. The static and non-power constrained nature of backbone nodes allow offering some exploitable features towards this goal, such as multi-radio and multi-channel support, stability, and increased CPU and storage capabilities. Such features have a strong impact on the design of the routing scheme, which makes inefficient to port existing solutions from wired and other wireless networks. As a consequence, in recent years, many alternative routing protocols have been proposed for WMNs. This survey paper presents the current stateof- the-art of routing protocols specifically designed for WMNs that try to maximize the throughput transferred by the network. First, a classification of routing protocols is provided. Second, the routing architecture is decomposed into three major building blocks. Open research issues related to each building block are also discussed. And finally, the main characteristics of the building blocks for each relevant routing protocol in the taxonomy are summarized.

The impact of synchronization on the performance of FDL buffers

Circumventing the speed bottleneck of electronic switching, novel switching approaches like optical burst switching (OBS) and optical packet switching (OPS) handle the switching of bursts (or packets) in backbone nodes optically, and include a set of fiber delay lines (FDLs) for optical buffering. While previous work acknowledges the performance difference between optical FDL buffers and electronic RAM buffers, the important role of synchronization herein has received little attention to date. Addressing this, we developed a single-wavelength FDL model that allows to capture the interplay between FDL buffer performance, burst size distribution and synchronization. Relying on generating functions, we constructed a discrete-time queueing model with batch arrivals that is valid for general burst and batch size distribution, and allows to quantify how synchronization impacts performance. This paper presents our model and compares its output for different synchronization levels. Whether or not buffer performance benefits from synchronization, turns out to depend strongly on the burst size distribution.

MCBT: Multi-Hop Cluster Based Stable Backbone Trees for Data Collection and Dissemination in WSNs

We propose a stable backbone tree construction algorithm using multi-hop clusters for wireless sensor networks (WSNs). The hierarchical cluster structure has advantages in data fusion and aggregation. Energy consumption can be decreased by managing nodes with cluster heads. Backbone nodes, which are responsible for performing and managing multi-hop communication, can reduce the communication overhead such as control traffic and minimize the number of active nodes. Previous backbone construction algorithms, such as Hierarchical Cluster-based Data Dissemination (HCDD) and Multicluster, Mobile, Multimedia radio network (MMM), consume energy quickly. They are designed without regard to appropriate factors such as residual energy and degree (the number of connections or edges to other nodes) of a node for WSNs. Thus, the network is quickly disconnected or has to reconstruct a backbone. We propose a distributed algorithm to create a stable backbone by selecting the nodes with higher energy or degree as the cluster heads. This increases the overall network lifetime. Moreover, the proposed method balances energy consumption by distributing the traffic load among nodes around the cluster head. In the simulation, the proposed scheme outperforms previous clustering schemes in terms of the average and the standard deviation of residual energy or degree of backbone nodes, the average residual energy of backbone nodes after disseminating the sensed data, and the network lifetime.

Load aware adaptive backbone synthesis in Wireless Mesh Networks

Wireless Mesh Networks (WMNs) are envisioned to support the wired backbone with a wireless Backbone Networks (BNet) for providing internet connectivity to large-scale areas. With a wide range of internet-oriented applications with different Quality of Service (QoS) requirement, the large-scale WMNs should have good scalability and large bandwidth. In this paper, a Load Aware Adaptive Backbone Synthesis (LAABS) algorithm is proposed to automatically balance the traffic flow in the WMNs. The BNet will dynamically split into smaller size or merge into bigger one according to statistic load information of Backbone Nodes (BNs). Simulation results show LAABS generates moderate BNet size and converges quickly, thus providing scalable and stable BNet to facilitate traffic flow.

Evaluation of physical carrier sense based spanner construction and maintenance as well as broadcast and convergecast in ad hoc networks

While the use of physical carrier sensing for medium access control in ad hoc wireless networks is well established, exploiting physical carrier sensing directly for network layer functions is largely unexplored. We conduct extensive simulation evaluations of recently proposed algorithms that directly exploit physical carrier sensing for backbone network (spanner) construction, broadcast, and convergecast in wireless ad hoc networks. Our algorithms accommodate interference ranges larger than transmission ranges, explicitly incorporate the medium access control and packet collisions, and do not require any prior knowledge of the network. For spanner construction, our algorithms include three self-stabilizing phases that establish leader nodes able to reach all nodes in one hop, assign the leaders non-interfering transmission rounds, and connect the leaders through gateway nodes. We evaluate the backbone construction and maintenance as well as broadcast and convergecast through simulations. We find that over 75% of the control messages for backbone network construction are received from physical carrier sensing. While the number of backbone nodes is relatively large, the backbone is very robust, quickly self-stabilizing, and only a fraction of the backbone nodes are used for broadcast.