Connectivity Based k-Hop Clustering in Wireless Networks

In this paper we describe several new clustering algorithms for nodes in a mobile ad hoc network. The main contribution is to generalize the cluster definition and formation algorithm so that a cluster contains all nodes that are at distance at most k hops from the clusterhead. We also describe algorithms for modifying cluster structure in the presence of topological changes. We also proposed an unified framework for most existing and new clustering algorithm where a properly defined weight at each node is the only difference in otherwise the same algorithm. This paper studied node connectivity and node ID as two particular weights, for k=1 and k=2. Finally, we propose a framework for generating random unit graphs with obstacles.     

An efficient routing protocol for the QoS support of large‐scale MANETs

The hierarchical routing algorithm is categorized as a kind of routing method using node clustering to create a hierarchical structure in large‐scale mobile ad hoc network (LMANET). In this paper, we proposed a new hierarchical clustering algorithm (HCAL) and a corresponded protocol for hierarchical routing in LMANET. The HCAL is designed based on a cost metric in the form of the link expiration time and node's relative degree. Correspondingly, the routing protocol for HCAL adopts a reactive protocol to control the existing cluster head (CH) nodes and handle proactive nodes to be considered as a cluster in LMANET. Hierarchical clustering algorithm jointly utilizes table‐driven and on‐demand routing by using a combined weight metric to search dominant set of nodes. This set is composed by link expiration time and node's relative degree to establish the intra/intercommunication paths in LMANET. The performance of the proposed algorithm and protocol is numerically evaluated in average end‐to‐end delay, number of CH per round, iteration count between the CHs, average CH keeping time, normalized routing overhead, and packet delivery ratio over a number of randomly generated benchmark scenarios. Furthermore, to corroborate the actual effectiveness of the HCAL algorithm, extensive performance comparisons are carried out with some state‐of‐the‐art routing algorithms, namely, Dynamic Doppler Velocity Clustering, Signal Characteristic‐Based Clustering, Dynamic Link Duration Clustering, and mobility‐based clustering algorithms.     

Unified routing protocol based on passive bandwidth measurement in heterogeneous WMNs

The past few years have witnessed a surge of wireless mesh networks (WMNs)‐based applications and heterogeneous WMNs are taking advantage of multiple radio interfaces to improve network performance. Although many routing protocols have been proposed for heterogeneous WMNs, most of them mainly relied on hierarchical or cluster techniques, which result in high routing overhead and performance degradation due to low utilization of wireless links. This is because only gateway nodes are aware of all the network resources. In contrast, a unified routing protocol (e.g., optimal link state routing (OLSR)), which treats the nodes and links equally, can avoid the performance bottleneck incurred by gateway nodes. However, OLSR has to pay the price for unification, that is, OLSR introduces a great amount of routing overhead for broadcasting routing message on every interface. In this paper, we propose unified routing protocol (URP), which is based on passive bandwidth measurement for heterogeneous WMNs. Firstly, we use the available bandwidth as a metric of the unification and propose a low‐cost passive available bandwidth estimation method to calculate expected transmission time that can capture the dynamics of wireless link more accurately. Secondly, based on the estimated available bandwidth, we propose a multipoint relays selection algorithm to achieve higher transmission ability and to help accelerate the routing message diffusion. Finally, instead of broadcasting routing message on all channels, nodes running URP transmit routing message on a set of selected high bandwidth channels. Results from extensive simulations show that URP helps improve the network throughput and to reduce the routing overhead compared with OLSR and hierarchical routing. Copyright © 2016 John Wiley & Sons, Ltd.     

Energy Efficient QoS Aware Hierarchical KF-MAC Routing Protocol in Manet

The paper proposes an energy efficient quality of services (QoS) aware hierarchical KF-MAC routing protocol in mobile ad-hoc networks. The proposed KF-MAC (K-means cluster formation firefly cluster head selection based MAC routing) protocol reduces the concentration of QoS parameters when the node transmits data from source to destination. At first, K-means clustering technique is utilized for clustering the network into nodes. Then the clustered nodes are classified and optimized by the firefly optimization algorithm to find cluster heads for the clustered nodes. The transmission of data begins in the network nodes and TDMA based MAC routing does communication. The observation on KF-MAC protocol performs well for QoS parameters such as bandwidth, delay, bit error rate and jitter. The evaluation of proposed protocol based on a simulation study concludes that the proposed protocol provides a better result in contrast to the existing fuzzy based energy aware routing protocol and modified dynamic source routing protocol. With KF-MAC protocol, the collision free data transmission with low average energy consumption is achieved.     

QoS routing based on multi-class nodes for mobile ad hoc networks

In this paper, we present a new quality of service (QoS) routing protocol for mobile ad hoc networks (MANETs). Most of the existing routing protocols assume homogeneous nodes in MANETs, i.e., all nodes have the same communication capabilities and characteristics. However, in many ad hoc networks, nodes are not the same. Some nodes have longer transmission range, larger transmission bandwidth, and are more reliable and robust than other nodes. We take advantage of the non-homogeneous property to design more efficient QoS routing protocol. And node location information is used to aid routing. We also develop a new algorithm to calculate end-to-end bandwidth for a given path. Our QoS routing protocol contains end-to-end bandwidth calculation and bandwidth reservation. QoS route is discovered and setup only when it is needed. Extensive simulation studies demonstrate the good performance of the QoS routing protocol.     

A green cluster‐based routing scheme for large‐scale wireless sensor networks

In wireless sensor networks (WSNs), clustering has been shown to be an efficient technique to improve scalability and network lifetime. In clustered networks, clustering creates unequal load distribution among cluster heads (CHs) and cluster member (CM) nodes. As a result, the entire network is subject to premature death because of the deficient active nodes within the network. In this paper, we present clustering‐based routing algorithms that can balance out the trade‐off between load distribution and network lifetime “green cluster‐based routing scheme.” This paper proposes a new energy‐aware green cluster‐based routing algorithm to preventing premature death of large‐scale dense WSNs. To deal with the uncertainty present in network information, a fuzzy rule‐based node classification model is proposed for clustering. Its primary benefits are flexibility in selecting effective CHs, reliability in distributing CHs overload among the other nodes, and reducing communication overhead and cluster formation time in highly dense areas. In addition, we propose a routing scheme that balances the load among sensors. The proposed scheme is evaluated through simulations to compare our scheme with the existing algorithms available in the literature. The numerical results show the relevance and improved efficiency of our scheme.     

A load balancing energy efficient clustering algorithm for MANETs

Nodes in mobile ad hoc Networks (MANETs) are characterized by their limited resources. Hence, the concept of clustering was introduced to allow spacial reuse of bandwidth and to minimize routing overhead. However, node mobility perturbs the stability of the network and affects the performance of other protocols such as scheduling, routing, and resource allocation, which makes re‐clustering the network to maintain up‐to‐date information at each node unavoidable. Consequently, clustering models for MANETS should be carefully designed while taking into consideration the fact that mobile nodes are energy constrained. In this paper, we propose a dynamic energy‐efficient clustering algorithm that prolongs the network lifetime by electing cluster‐heads taking into consideration, in addition to other parameters such as mobility, their residual energies and making them dynamically monitor their energy consumption to either diminish the number of their cluster‐members or relinquish their roles. We have evaluated the performance of the proposed clustering model and compared it with other related clustering approaches found in the literature. Obtained results show the efficiency of the proposed algorithm. Copyright © 2010 John Wiley & Sons, Ltd.     

移动自组织网络预测分簇算法的路由协议

针对移动自组织网络中传统分簇算法存在稳定性低、网络开销大的问题,在WCA分簇算法的基础上,提出一种带有预测机制的EWCA-MP(Efficient on-demand Weighted Clustering Algorithm using Mobility Prediction)分簇算法,该算法在簇头选择时充分考虑节点间的链路保持时间,在簇维护阶段引入模糊逻辑的概念,对Hello消息包的广播周期进行优化。并将其应用于CBRP中,提出了一种ECBRP-MP(Efficient Cluster Based Routing Protocol using Mobility Prediction)移动预测的分簇路由协议。仿真结果表明,EWCA-MP算法在簇头数目、单位时间内节点转移次数和统治集更新次数明显减少,ECBRP-MP路由协议在路由开销、分组投递率的性能得到优化。     

The Optimization of Combination Scheme in Cooperative Spectrum Sensing Based on the Practical Reporting Frame Format

Wireless mesh networks (WMNs) are emerged as prominent solution to provide seamless connection to the internet. WMNs are typically used for providing broadband wireless internet access to a large number of users and networks. Guaranteeing the quality of service to end users with efficient resource utilization is a challenging issue in WMNs. To accomplish this, we propose a hybrid routing protocol for wireless mesh networks. It is a combination of intra cluster routing protocol (ICR) and inter cluster routing protocol for mesh networks (ICMR). Intra cluster routing protocol is intended to facilitate the communication between mesh clients within a same cluster and inter cluster routing protocol (ICMR) intended to facilitate the communication for mesh clients from different clusters. Intra cluster routing protocol is a proactive type of routing protocol and inter cluster routing protocol is a reactive type of routing protocol. The performance of the proposed protocol is analyzed and the results shown superior performance compared to baseline routing protocols in terms of throughput, end to end delay, packet delivery ratio and jitter.     

Evaluation of Clustering Algorithms in Ad Hoc Mobile Networks

Ad hoc mobile networks are free of any infrastructures and their nodes are not aware of the connections of the network locating in, since the structure of these networks is dynamic. To send data to other nodes, each node should detect the sending path and then save it. Due to their dynamic nature, these types of networks face design complexity and limitations such as a lack of specific infrastructure and the change of the infrastructure with passing the time, the limitation of energy, bandwidth, and the considerations of quality and security. Therefore, bandwidth optimization, power and energy control and an improvement in transmission quality are challenges of these types of networks in routing. To meet these challenges, the node clustering methods were welcomed for less energy consumption and longer network lifetime. In this paper, we deal with a systematic literature review of different clustering methods and propose a general categorization for them. Furthermore, we compare the performance the methods as well as the related algorithms and their strengths and weaknesses. Finally, we rank the algorithms regarding the four parameters of transmission range, mobility speed, battery, and connectivity degree using the multi-criterion decision-making and analytical hierarchical process techniques.

     

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.     

LIDAR: a protocol for stable and energy-efficient clustering of ad-hoc multihop networks

Clustering has been proposed as a promising method for simplifying the routing process in mobile ad hoc networks (MANETs). The main objective in clustering is to identify suitable node representatives, i.e. cluster heads (CHs) to store routing and topology information; CHs should be elected so as to maximize clusters stability, that is to prevent frequent cluster re-structuring. Since CHs are engaged on packet forwarding they are prone to rapidly drop their energy supplies, hence, another important objective of clustering is to prevent such node failures. Recently proposed clustering algorithms either suggest CH election based on node IDs (nodes with locally lowest ID value become CHs) or take into account additional metrics (such as energy and mobility) and optimize initial clustering. Yet, the former method is biased against nodes with low IDs (which are likely to serve as CHs for long periods and therefore run the risk of rapid battery exhaustion). Similarly, in the latter method, in many situations (e.g. in relatively static topologies) re-clustering procedure is hardly ever invoked; hence initially elected CHs soon suffer from energy drainage. Herein, we propose LIDAR, a novel clustering method which represents a major improvement over alternative clustering algorithms: node IDs are periodically re-assigned so that nodes with low mobility rate and high energy capacity are assigned low ID values and, therefore, are likely to serve as CHs. Therefore, LIDAR achieves stable cluster formations and balanced distribution of energy consumption over mobile nodes. Our protocol also greatly reduces control traffic volume of existing algorithms during clustering maintenance phase, while not risking the energy availability of CHs. Simulation results demonstrate the efficiency, scalability and stability of our protocol against alternative approaches.     

A Genetic‐Algorithm‐Based Optimized Clustering for Energy‐Efficient Routing in MWSN

With the increasing demands for mobile wireless sensor networks in recent years, designing an energy‐efficient clustering and routing protocol has become very important. This paper provides an analytical model to evaluate the power consumption of a mobile sensor node. Based on this, a clustering algorithm is designed to optimize the energy efficiency during cluster head formation. A genetic algorithm technique is employed to find the near‐optimal threshold for residual energy below which a node has to give up its role of being the cluster head. This clustering algorithm along with a hybrid routing concept is applied as the near‐optimal energy‐efficient routing technique to increase the overall efficiency of the network. Compared to the mobile low energy adaptive clustering hierarchy protocol, the simulation studies reveal that the energy‐efficient routing technique produces a longer network lifetime and achieves better energy efficiency.     

Admission control on multipath routing in 802.11-based wireless mesh networks

Admission control (AC) is a mechanism for meeting bandwidth requirements of data transmissions. Early research on admission control for wireless mesh networks (WMNs) was centered around single-path routing. Compared to single-path routing, parallel multipath routing may offer more reliable network services and better load balancing. Applying admission control to multipath routing could further improve service quality, but it also faces a number of challenges. For example, transmission on one path may affect transmission on a neighboring path. Addressing these challenges, this paper presents an AC algorithm on parallel multipath routing for WMNs. In particular, we formulate an optimization problem for achieving the best service based on available bandwidth and bandwidth consumption of to-be-admitted data sessions. While solving this problem is a complex task, we devise an optimal algorithm for selecting two node-disjoint paths with rate allocation, and propose a distributed multipath routing and admission control protocol to achieve a near-optimal solution. Simulations show that MRAC is efficient and effective in meeting bandwidth requirements.     

Rendezvous-based data dissemination for supporting mobile sinks in multi-hop clustered wireless sensor networks

In wireless sensor networks, a clustering-based technique is considered as an efficient approach for supporting mobile sinks without using position information. It exploits a Backbone-based Virtual Infrastructure (BVI) which uses only cluster heads (CHs) to construct routing structures. Since sensor nodes have constrained energy and are failure-prone, the effective design of both a clustering structure to construct a BVI and a routing protocol in the BVI is an important issue to achieve energy-efficient and reliable data delivery. However, since previous studies use one-hop clustering for a BVI, they are not robust against node and link failures and thus leading low data delivery ratio. They also use flooding-based routing protocols in a BVI and thus leading high energy consumption. Thus, in this paper, we propose a rendezvous-based data dissemination protocol based on multi-hop clustering (RDDM). Since RDDM uses a multi-hop clustering to provide enough backup sensor nodes to substitute a CH and enough backup paths between neighbor CHs, it can provide high robustness against node and link failures. By using a rendezvous CH, RDDM constructs routing paths from source nodes to mobile sinks without flooding in our BVI and thus can save energy of sensor nodes. By considering movement types of sinks, RDDM finds out a shorter path between a source node and a mobile sink through signaling only between neighbor CHs and thus can reduce the energy consumption. Analysis and simulation results show that RDDM provides better performance than previous protocols in terms of energy consumption and data delivery ratio.     

Clustering routing protocol based on improved PSO algorithm in WSN

Aiming at the problem that the location distribution of cluster head nodes filtered by wireless sensor network clustering routing protocol was unbalanced and the data transmission path of forwarding nodes was unreasonable,which would increase the energy consumption of nodes and shorten the network life cycle,a clustering routing protocol based on improved particle swarm optimization algorithm was proposed.In the process of cluster head election,a new fitness function was established by defining the energy factor and position equalization factor of the node,the better candidate cluster head node was evaluated and selected,the position update speed of the candidate cluster head nodes was adjusted by the optimized update learning factor,the local search and speeded up the convergence of the global search was expanded.According to the distance between the forwarding node and the base station,the single-hop or multi-hop transmission mode was adopted,and a multi-hop method was designed based on the minimum spanning tree to select an optimal multi-hop path for the data transmission of the forwarding node.Simulation results show that the clustering routing protocol based on improved particle swarm optimization algorithm can elect cluster head nodes and forwarding nodes with more balanced energy and location,which shortened the communication distance of the network.The energy consumption of nodes is lower and more balanced,effectively extending the network life cycle.     

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.     

Energy-aware redundancy-aware clustering in wireless sensor networks using Spined Loach Searching Optimization

Wireless sensor networks play dominant role in data communication in many engineering applications and faces lot of challenges in its implementation. Energy conservation is also significantly required in these systems as the sensor nodes are battery operated. Hence, the energy efficient-based technique needs to be implemented in data transmission. The most widely used methods are clustering-based data transmission and energy efficient routing detection. In clustering, the proper selection of cluster head (CH) node is important to ensure energy balancing. The CH node should have more residual energy as it does many transmissions in the network. Moreover, the location of CH node should be nearer to all member nodes in the cluster. The clustering process must also perform the job of avoiding unnecessary transmissions. By considering these factors, the CH node can be optimally selected using Spined Loach Searching Optimization algorithm. The food searching behavior and environmental suitability for spiny loach fish living are deliberated to develop this bio-inspired algorithm. In addition, the redundant transmissions inside the clusters can be reduced by employing a new technique called Least Difference Threshold Based Similarity Grouping. This work improves energy efficiency comparing with the conventional low energy adaptive clustering hierarchy protocol, and it is evaluated by setting the network in simulation environment. The network lifetime is increased; energy consumption, delay of transmission and the message cost are reduced.     

基于分布式密钥共享的UWSN安全分簇方案

针对无照料的无线传感网（UWSN, unattended wireless sensor network）收集效率和安全问题,提出一种安全的UWSN分簇方案,实现了一种三角形网格图的网络拓扑分簇算法,并可完成簇头对移动节点的认证。该方案利用三角形的性质提高了网络的连通度,折中数据收集效率与能耗;将分布式密钥共享方案与分簇算法无缝结合,在网络中高效地搜索移动节点公钥信息,从而在本地不存有对应公钥信息的情况下验证签名信息。实验结果表明,该算法在节点密度越大的情况下分簇越趋近于正三角形网格图,且分簇后的网络对于低于20%节点变节有95%以上概率抵御攻击。     

On Routing in Multichannel Wireless Mesh Networks: Challenges and Solutions

Wireless mesh networks have emerged as a promising solution to providing cost-effective last-mile connectivity. Employing multiple channels is shown to be an effective approach to overcoming the problem of capacity degradation in multihop wireless networks. However, existing routing schemes that are designed for single-channel multihop wireless networks may lead to inefficient routing paths in multichannel WMNs. To fully exploit the capacity gain due to multiple channels, one must consider the availability of multiple channels and distribute traffic load among channels as well as among nodes in routing algorithms. In this article we focus on the routing problem in multichannel WMNs. We highlight the challenges in designing routing algorithms for multichannel WMNs and examine existing routing metrics that are designed for multichannel WMNs, along with a simulation-based performance study. We also address some open research issues related to routing in multichannel WMNs.