Sustained service lookup in areas of sudden dense population

As mobility became the norm rather than the exception, location‐based services are playing more of a key role in assisting mobile users. In this paper, we address the challenges of providing location‐based services to users in areas of sudden population increases, such as stadiums and traffic jams. A sudden increase in the number of mobile users leads to an increasing demand for the already scarce wireless bandwidth, thus causing dramatical throughput degradation and an increase in connectivity failures. We propose a hybrid model within which a peer‐to‐peer mode is deployed to assist the cellular‐based network whenever a sudden increase in population density is sensed by the base station. Location‐based data is migrated to selected elite nodes, thus allowing other peer nodes to get their information locally. This approach is proven, through experimental results, to decrease the query response time and number of query failures. Copyright © 2006 John Wiley & Sons, Ltd.     

Optimal load balanced clustering in homogeneous wireless sensor networks

Balancing the load among sensor nodes is a major challenge for the long run operation of wireless sensor networks. When a sensor node becomes overloaded, the likelihood of higher latency, energy loss, and congestion becomes high. In this paper, we propose an optimal load balanced clustering for hierarchical cluster‐based wireless sensor networks. We formulate the network design problem as mixed‐integer linear programming. Our contribution is 3‐fold: First, we propose an energy aware cluster head selection model for optimal cluster head selection. Then we propose a delay and energy‐aware routing model for optimal inter‐cluster communication. Finally, we propose an equal traffic for energy efficient clustering for optimal load balanced clustering. We consider the worst case scenario, where all nodes have the same capability and where there are no ways to use mobile sinks or add some powerful nodes as gateways. Thus, our models perform load balancing and maximize network lifetime with no need for special node capabilities such as mobility or heterogeneity or pre‐deployment, which would greatly simplify the problem. We show that the proposed models not only increase network lifetime but also minimize latency between sensor nodes. Numerical results show that energy consumption can be effectively balanced among sensor nodes, and stability period can be greatly extended using our models.     

紫外光无线传感器网络节能的研究与仿真

为了减少无线传感器网络节点的能量消耗,采用紫外光作为无线传感器网络的信息载体,研究了紫外光传感器节点的能量模型。理论分析了单跳节能和多跳节能,得出了计算最优跳数的数学表达式,并对单跳通信、多跳通信和最优跳通信的平均能量消耗进行了计算机仿真,仿真结果与理论分析一致;对于多跳通信带来的能量消耗不均匀的问题,利用移动sink节点来解决,通过仿真对比了sink节点不同移动速率对网络平均能量消耗、丢包率和端到端时延的影响。结果表明,借助移动sink节点可以降低网络的平均能量消耗,但要根据场景选择合适的移动速率。     

A queuing model for distributed scheduling in IEEE 802.16 wireless mesh networks

The IEEE 802.16 standard for wireless broadband networks includes the mesh mode in its specifications, where network nodes interact to deliver packets from a client to a remote destination through intermediate nodes. This paper presents a study of the capacity of IEEE 802.16 wireless networks in mesh mode by using M/G/1/L queuing model that represents each network node by incorporating the features of the standard in order to calculate the average delay and throughput in the node. An iterative method integrates the calculation results at each node, obtaining the end‐to‐end delay from any node of the mesh to the Base Station. Because of multiple hops, a node far from the Base Station may have its flows damaged. To minimize this problem, we propose a criterion for a fair distribution of resources. We show the numerical results of the model which indicate a good fit when compared with simulation results. Copyright © 2013 John Wiley & Sons, Ltd.     

Multifold node authentication in mobile ad hoc networks

An ad hoc network is a collection of nodes that do not need to rely on a predefined infrastructure to keep the network connected. Nodes communicate amongst each other using wireless radios and operate by following a peer‐to‐peer network model. In this article, we propose a multifold node authentication approach for protecting mobile ad hoc networks. The security requirements for protecting data link and network layers are identified and the design criteria for creating secure ad hoc networks using multiple authentication protocols are analysed. Such protocols, which are based on zero‐knowledge and challenge‐response techniques, are presented through proofs and simulation results. Copyright © 2007 John Wiley & Sons, Ltd.     

An energy‐efficient clustering and multipath routing for mobile wireless sensor network using game theory

Most of the current generation sensor nodes of mobile wireless sensor network (MWSN) are designed to have heterogeneous mobility to adapt itself in the applied environment. Energy optimization in MWSN with heterogeneous mobility is very challenging task. In this paper, a heterogeneous game theoretical clustering algorithm called mobile clustering game theory–1 (MCGT‐1) is proposed for energy optimization in a heterogeneous mobile sensor environment. Energy optimization is achieved through energy‐efficient cluster head election and multipath routing in the network. A heterogeneous clustering game is modelled with varying attributes and located an asymmetric equilibrium condition for a symmetric game with mixed strategies. The real‐time parameters, namely, predicted remaining energy, distance between a base station and nodes, distance between nodes, and mobility speed, were used to calculate the probability to elect the cluster head (CH). The efficient multipath routing is achieved through prior energy prediction strategy. It has mitigated the generation of “hot spots,” reducing its delay and improving the overall residual energy of the network. Simulation results showed that the average lifetime of MCGT‐1 has increased by 6.33 %, 13.1% and 14.2% and the PDR has improved by 4.8%,11.8%, and 17.2% than MCGT, LEACH‐ME and LEACH‐M respectively. The hot spot delay is reduced to 0.063025 seconds, improving the efficiency of the network.     

Cluster‐based mobility management algorithms for wireless mesh networks

Wireless mesh networks (WMNs) have been the recent advancements and attracting more academicians and industrialists for their seamless connectivity to the internet. Radio resource is one among the prime resources in wireless networks, which is expected to use in an efficient way especially when the mobile nodes are on move. However, providing guaranteed quality of service to the mobile nodes in the network is a challenging issue. To accomplish this, we propose 2 clustering algorithms, namely, static clustering algorithm for WMNs and dynamic clustering algorithm for WMNs. In these algorithms, we propose a new weight‐based cluster head and cluster member selection process for the formation of clusters. The weight of the nodes in WMN is computed considering the parameters include the bandwidth of the node, the degree of node connectivity, and node cooperation factor. Further, we also propose enhanced quality of service enabled routing protocol for WMNs considering the delay, bandwidth, hopcount, and expected transmission count are the routing metrics. The performance of the proposed clustering algorithms and routing protocol are analyzed, and results show high throughput, high packet delivery ratio, and low communication cost compared with the existing baseline mobility management algorithms and routing protocols.     

A service level model and Internet mobility monitor

Mobility is gaining a tremendous interest among Internet users and wireless access networks are increasingly being installed to enable mobile usage. Internet mobility requires solutions to move between access networks with maintained network connectivity. Seamless mobility in turn means that the experience of using a service is unaffected while being mobile. Communication in next generation networks will use multiple access technologies, creating a heterogeneous network environment. Further, roaming between network service providers may take place. To enable mobile nodes to move between access networks within as well as between network service providers with minimal disruption, nodes should be able to maintain multiple active network connections. With the usage of multihomed nodes, seamless mobility can be achieved in already installed infrastructures, not providing mobility support. Mobility in heterogeneous access networks also requires network selections that scale for services. In this article we propose an architecture where application service providers and network service providers define service levels to be used by a mobile node and its user. The user selects a service and the service level from an application service provider. When performing access network selection, information received as part of an application service level will be used to find a network that supports the service required. The performance of available access networks will be monitored and considered when making the decision. Our proposed architecture provides solutions to move flows between interfaces in real-time based on network performance, quality of service signalling to correspondent nodes, and cancellation of flows to give way for more important traffic.     

A multi‐anchoring approach in mobile IP networks

Many recent mobility solutions, including derivatives of the well‐known Mobile IP as well as emerging protocols employed by future Internet architectures, propose to realize mobility management by distributing anchoring nodes (Home Agents or other indirection agents) over the Internet. One of their main goals is to address triangle routing by optimizing routes between mobile nodes and correspondent nodes. Thus, a key component of such proposals is the algorithm to select proper mobility anchoring nodes for mobile nodes. However, most current solutions adopt a single‐anchoring approach, which means each mobile node attaches to a sole mobility anchor at one time. In this paper, “we argue that the single‐anchoring approach has drawbacks when facing various mobility scenarios. Then, we offer a novel multi‐anchoring approach that allows each mobile node to select an independent mobility anchor for each correspondent node. We show that in most cases our proposal gains more performance benefits with an acceptable additional cost by evaluation based on real network topologies. For the cases that lead to potential high cost, we also provide a lightweight version of our solution which aims to preserve most performance benefits while keeping a lower cost. At last, we demonstrate how our proposal can be integrated into current Mobile IP networks. Copyright © 2017 John Wiley & Sons, Ltd.     

Route Optimization Using Tree Information Option for Nested Mobile Networks

Mobile IP is the basic solution to provide host mobility, whereas network mobility refers to the concept of collective mobility of a set of nodes. In the simplest scenario, a mobile network moves as a single unit with one mobile router (MR) that connects it to the global Internet. Also, multiple mobile networks can be nested in a hierarchical form, e.g., a wireless personal area network (PAN) in a vehicular network. In a nested mobile network, multiple MRs form a tree hierarchy in which the root MR is called the top-level mobile router (TLMR). Nested mobile networks exhibit the pinball routing problem, which becomes worse in proportion to the number of nested levels in the hierarchy. To solve this problem, we propose a routing optimization scheme using a tree information option (ROTIO) that extends the NEMO basic support protocol. In the ROTIO scheme, each MR in the nested mobile network sends two binding updates (BUs): one to its home agent and the other to the TLMR. The former BU contains the TLMR's home address, while the latter contains routing information between the issuing MR and the TLMR. This alleviates the pinball routing problem significantly. Now, a packet from a correspondent node only needs to visit two transit nodes (the home agents of the MR and the TLMR), regardless of the degree of nesting. Moreover, the ROTIO scheme provides location privacy and mobility transparency. We also extend ROTIO to perform routing between two mobile network nodes inside the same nested mobile network more efficiently and to substantially reduce the disruption when a mobile network hands off.     

A distributed utility‐based scheduling for peer‐to‐peer video streaming over wireless networks

Interactive multimedia applications such as peer‐to‐peer (P2P) video services over the Internet have gained increasing popularity during the past few years. However, the adopted Internet‐based P2P overlay network architecture hides the underlying network topology, assuming that channel quality is always in perfect condition. Because of the time‐varying nature of wireless channels, this hardly meets the user‐perceived video quality requirement when used in wireless environments. Considering the tightly coupled relationship between P2P overlay networks and the underlying networks, we propose a distributed utility‐based scheduling algorithm on the basis of a quality‐driven cross‐layer design framework to jointly optimize the parameters of different network layers to achieve highly improved video quality for P2P video streaming services in wireless networks. In this paper, the quality‐driven P2P scheduling algorithm is formulated into a distributed utility‐based distortion‐delay optimization problem, where the expected video distortion is minimized under the constraint of a given packet playback deadline to select the optimal combination of system parameters residing in different network layers. Specifically, encoding behaviors, network congestion, Automatic Repeat Request/Query (ARQ), and modulation and coding are jointly considered. Then, we provide the algorithmic solution to the formulated problem. The distributed optimization running on each peer node adopted in the proposed scheduling algorithm greatly reduces the computational intensity. Extensive experimental results also demonstrate 4–14 dB quality enhancement in terms of peak signal‐to‐noise ratio by using the proposed scheduling algorithm. Copyright © 2015 John Wiley & Sons, Ltd.     

On the effectiveness of movement prediction to reduce energy consumption in wireless communication

Node movement can be exploited to reduce the energy consumption of wireless network communication. The strategy consists in delaying communication until a mobile node moves close to its target peer node within an application- imposed deadline. We evaluate the performance of various heuristics that, based on the movement history of the mobile node, estimate an optimal time (in the sense of least energy use) of communication subject to the delay constraint. We evaluate the impact of the node movement model, length of movement history maintained, allowable delay, single hop versus multiple hop communication, and size of data transfer on the energy consumption. We also present measurement results on an iPAQ pocket PC that quantity energy consumption in executing the prediction algorithms. Our results show that, with relatively simple and, hence, efficient prediction heuristics, energy savings in communication can significantly outweigh the energy expenses in executing the prediction algorithms. Moreover, it is possible to achieve robust system performance across diverse node movement models.     

E2DTS: An energy efficiency distributed time synchronization algorithm for underwater acoustic mobile sensor networks

Time synchronization plays an important role in wireless sensor network applications and energy conservation. In this paper, we focus on the need of time synchronization in underwater acoustic mobile sensor networks (UAMSNs). Several time synchronization algorithms have been carried out in this issue. But most of them are proposed for RF-based wireless sensor networks, which assume that the propagation delay is negligible. In UAMSNs, the assumption about rapid communication is incorrect because the communication is primarily via acoustic channel, so the propagation speed is much slower than RF. Furthermore, the propagation delay in underwater environment is time-varying due to the nodes’ mobility. We present an energy efficiency distributed time synchronization algorithm (called “E²DTS”) for those underwater acoustic node mobility networks. In E²DTS, both clock skew and offset are estimated. We investigate the relationship between time-varying propagation delay and nodes mobility, and then estimate the clock skew. At last skew-corrected nodes send local timestamp to beacon node to estimate its clock offset. Through analysis and simulation, we show that it achieves high level time synchronization precision with minimal energy cost.     

Mobility aided localization of wireless sensor networks with inaccurate range measurements

This paper studies the relationship between mobility, navigation and localization in the context of wireless sensor networks with mobile beacons. It is observed that mobility can aid in network node localization and that once localized, the network nodes can localize and track a mobile object and guide its navigation. A distributed kernel-based algorithm is proposed that enables the nodes to establish confident position estimates in the presence of ranging inaccuracies. The proposed approach features robustness with respect to range measurement inaccuracies, low complexity and distributed implementation, using only local information. Simulation validates our approach viable.     

Multi-Hop Wireless Backhaul Networks above 10 GHz: Connectivity and Critical Density Evaluation

Microwave links are the obvious mobile backhauling solution for many mobile operators. Multi-hops are likely to be necessary in order to ensure connectivity for mobile backhaul solutions. The subject of the present paper is the evaluation of the connectivity of wireless multi-hop backhaul networks assuming high frequency transmissions among the relays. A novel analytical physical propagation and engineering model is presented for the calculation of the connectivity of wireless multi-hop networks that appropriate for operating frequencies above 10 GHz. Assuming equal power transmissions from every node and a random spatial node distribution following the homogeneous Poisson process, we calculate the node isolation probability. Furthermore, we calculate the minimum required node density in order to keep the backhaul network almost connected. The sensitivity of the isolation probability and of the minimum node density on frequency of operation, transmission power and climatic conditions is also investigated. Some useful conclusions are drawn.     

Non‐cooperative game‐based packet ferry forwarding for sparse mobile wireless networks

In sparse mobile wireless networks, normally, the mobile nodes are carried by people, and the moving activity of nodes always happens in a specific area, which corresponds to some specific community. Between the isolated communities, there is no stable communication link. Therefore, it is difficult to ensure the effective packet transmission among communities, which leads to the higher packet delivery delay and lower successful delivery ratio. Recently, an additional ferry node was introduced to forward packets between the isolated communities. However, most of the existing algorithms are working on how to control the trajectory of only one ferry work in the network. In this paper, we consider multiple ferries working in the network scenario and put our main focus on the optimal packet selection strategy, under the condition of mutual influence between the ferries and the buffer limitation. We introduce a non‐cooperative Bayesian game to achieve the optimal packet selection strategy. By maximizing the individual income of a ferry, we optimize the network performance on packet delivery delay and successful delivery ratio. Simulation results show that our proposed packet selection strategy improves the network performance on packet delivery delay and successful delivery ratio. Copyright © 2013 John Wiley & Sons, Ltd.     

Invincible AODV to detect black hole and gray hole attacks in mobile ad hoc networks

Today's communication world is majorly driven by mobile nodes that demand wireless systems for their data relay. One such network is mobile ad hoc network, which is a purely wireless network with which communication is feasible instantly without any aid of preexisting infrastructure; due to this magnificent feature, it has a wide variety of applications. Mobile ad hoc network hinges on cooperative nature of the mobile nodes for relaying data. But at the same time, nodes relaying data for others may compromise, leading to various security attacks. Two main security attacks that drastically bring down the performance of mobile ad hoc network are black hole and gray hole attacks. In this paper, we propose 2 versions of invincible Ad hoc On‐Demand Distance Vector protocol to detect black hole and gray hole nodes that have bypassed preventive mechanism during route discovery process. First is the basic version, which is based on node‐to‐node frame check sequence tracking mechanism, and second is the enhanced version, which is based on signed frame check sequence tracking mechanism. They create a deterrent environment addressing all kinds of black and gray hole attacks. They also provide reliable data transmission to all the nonmalicious nodes in the network by using end‐to‐end authentication mechanism. Simulation results show better performance in packet delivery ratio when compared with other contemporary solutions while addressing all kinds of black and gray hole attacks. It shows significant improvement in end‐to‐end delay and normalized routing load over Ad hoc On‐Demand Distance Vector under black hole or gray hole attacks and also shows better throughput and packet delivery ratio than the existing solution.     

Energy‐conserving data gathering by mobile mules in a spatially separated wireless sensor network

This paper considers a spatially separated wireless sensor network, which consists of a number of isolated subnetworks that could be far away from each other in distance. We address the issue of using mobile mules to collect data from these sensor nodes. In such an environment, both data‐collection latency and network lifetime are critical issues. We model this problem as a bi‐objective problem, called energy‐constrained mule traveling salesman problem (EM‐TSP), which aims at minimizing the traversal paths of mobile mules such that at least one node in each subnetwork is visited by a mule and the maximum energy consumption among all sensor nodes does not exceed a pre‐defined threshold. Interestingly, the traversal problem turns out to be a generalization of the classical traveling salesman problem (TSP), an NP‐complete problem. With some geometrical properties of the network, we propose some efficient heuristics for EM‐TSP. We then extend our heuristics to multiple mobile mules. Extensive simulation results have been conducted, which show that our proposed solutions usually give much better solutions than most TSP‐like approximations. Copyright © 2011 John Wiley & Sons, Ltd.     

An energy aware algorithm for OLSR clustering

One of the important aspects of a mobile ad hoc network (MANET) is the limitation of the amount of available energy and the network lifetime. The tremendous amount of using mobile nodes in wireless communication medium makes energy efficiency a fundamental requirement for MANETs. In this paper, we propose a novel energy aware clustering algorithm for the optimized link state routing (OLSR) routing protocol. This algorithm takes into account the node density and mobility and gives major improvements regarding the number of elected cluster heads. Our objective is to elect a reasonable number of cluster heads that will serve for hierarchical routing based on OLSR. The proposed algorithm aims to increase the network lifetime by considering the ad hoc residual energy while taking routing decisions. It also optimizes the delay of carried flows by adopting a selective forwarding approach based on a hierarchical routing model.