一种基于位置和能量的WSN改进分簇协议

针对LEACH分簇路由协议中簇首随机选择,没有考虑节点的剩余能量和地理位置,可能导致分簇和网络能耗不均衡这一问题,研究了一种同时考虑了节点位置和剩余能量信息的改进分簇路由协议,使成为簇头的节点在簇的中心位置,从而使簇头在簇内的位置更加合理,避免了簇内的部分节点由于离簇头过远,增加传输损耗的缺点,有利于网络性能的提高。仿真结果表明,研究的分簇路由协议能使簇的划分更加均匀,能量的消耗更加节省,从而延长了WSN网络的生存时间。     

Energy and Spatial Reuse Efficient Network-Wide Real-Time Data Broadcasting in Mobile Ad Hoc Networks

In this paper, we present NB-TRACE, which is an energy-efficient network-wide voice broadcasting architecture for mobile ad hoc networks. In the NB-TRACE architecture, the network is organized into overlapping clusters through a distributed algorithm, where the clusterheads create a nonconnected dominating set. Channel access is regulated through a distributed TDMA scheme maintained by the clusterheads. The first group of packets of a broadcast session is broadcast through flooding, where each data rebroadcast is preceded by an acknowledgment to the upstream node. Nodes that do not get an acknowledgment for a predetermined time, except the clusterheads, cease to rebroadcast, which prunes the redundant retransmissions. The connected dominating set formed through this basic algorithm is broken in time due to node mobility. The network responds to the broken links through multiple mechanisms to ensure the maintenance of the connected dominating set. We compare NB-TRACE with four network layer broadcast routing algorithms (Flooding, Gossiping, Counter-based broadcasting, and Distance-based broadcasting) and three medium access control protocols (IEEE 802.11, SMAC, and MH-TRACE) through extensive ns-2 simulations. Our results show that NB-TRACE outperforms other network/MAC layer combinations in minimizing energy dissipation and optimizing spatial reuse, while producing competitive QoS performance.     

Performance comparison of trust-based reactive routing protocols

Ad hoc networks, due to their improvised nature, are frequently established in insecure environments and hence become susceptible to attacks. These attacks are launched by participating malicious nodes against different network services. Routing protocols, which act as the binding force in these networks, are a common target of these nodes. A number of secure routing protocols have recently been proposed, which make use of cryptographic algorithms to secure the routes. However, in doing so, these protocols entail a number of prerequisites during both the network establishment and operation phases. In contrast, trust-based routing protocols locate trusted rather than secure routes in the network by observing the sincerity in participation by other nodes. These protocols thus permit rapid deployment along with a dynamically adaptive operation, which conforms with the current network situation. In this paper, we evaluate the performance of three trust-based reactive routing protocols in a network with varying number of malicious nodes. With the help of exhaustive simulations, we demonstrate that the performance of the three protocols varies significantly even under similar attack, traffic, and mobility conditions. However, each trust-based routing protocol has its own peculiar advantage making it suitable for application in a particular extemporized environment.     

Variable Bit Rate Flow Routing in Wireless Sensor Networks

Since energy constraint is a fundamental issue for wireless sensor networks, network lifetime performance has become a key performance metric for such networks. In this paper, we consider a two-tier wireless sensor network and focus on the flow routing problem for the upper tier aggregation and forwarding nodes (AFNs). Specifically, we are interested in how to perform flow routing among the nodes when the bit rate from each source node is time-varying. We present an algorithm that can be used to construct a flow routing solution with the following properties: (1) If the average rate from each source node is known a priori, then flow routing solution obtained via such algorithm is optimal and offers provably maximum network lifetime performance; (2) If the average rate of each source node is unknown but is within a fraction (epsiv) of an estimated rate value, then network lifetime by the proposed flow routing solution is within 2epsiv/1-epsiv from the optimum. These results fill in an important gap in theoretical foundation for flow routing in energy-constrained sensor networks.     

Multi-hop Clustering Based on Neighborhood Benchmark in Mobile Ad-hoc Networks

Large-scale mobile ad-hoc networks require flexible and stable clustered network structure for efficient data collection and dissemination. In this paper, a technique is presented to construct multi-hop clusters with balanced sizes, based on the neighborhood benchmark (NB) to quantify the connectivity and link stability of mobile nodes. By exploiting autonomous clusterhead selection and a specialized handshake process with the clusterheads, the nodes with highest NB scores are selected as clusterheads and all the clusters constructed are connected. The deviation of cluster sizes is kept small using a partial probability-based approach. Our technique generates highly stable multi-hop clusters with low overhead, and provides the flexibility of controlling the cluster radius adaptively for various network applications.     

ABRP: Anchor-based Routing Protocol for Mobile Ad Hoc Networks

Ad hoc networks, which do not rely on any infrastructure such as access points or base stations, can be deployed rapidly and inexpensively even in situations with geographical or time constraints. Ad hoc networks are attractive in both military and disaster situations and also in commercial uses like sensor networks or conferencing. In ad hoc networks, each node acts both as a router and as a host. The topology of an ad hoc network may change dynamically, which makes it difficult to design an efficient routing protocol. As more and more wireless devices connect to the network, it is important to design a scalable routing protocol for ad hoc networks. In this paper, we present Anchor-based Routing Protocol (ABRP), a scalable routing protocol for ad hoc networks. It is a hybrid routing protocol, which combines the table-based routing strategy with the geographic routing strategy. However, GPS (Global Positioning System) (Kaplan, Understanding GPS principles and Applications, Boston: Artech House publishers, 1996) support is not needed. ABRP consists of a location-based clustering protocol, an intra-cell routing protocol and an inter-cell routing protocol. The location-based clustering protocol divides the network region into different cells. The intra-cell routing protocol routes packets within one cell. The inter-cell routing protocol is used to route packets between nodes in different cells. The combination of intra-cell and inter-cell routing protocol makes ABRP highly scalable, since each node needs to only maintain routes within a cell. The inter-cell routing protocol establishes multiple routes between different cells, which makes ABRP reliable and efficient. We evaluate the performance of ABRP using ns2 simulator. We simulated different size of networks from 200 nodes to 1600 nodes. Simulation results show that ABRP is efficient and scales well to large networks. ABRP combines the advantages of multi-path routing strategy and geographic routing strategy—efficiency and scalability, and avoids the burden—GPS support.     

Performance of a broadcast packet switch

The results of a simulation study undertaken to evaluate a high-performance packet-switching fabric supporting point-to-point and multipoint communications are presented. This switching fabric contains several components, each based on conventional binary routing networks. The most novel element is the copy network, which performs the packet replication needed for multipoint connections. Results characterizing the performance of the copy network are presented. Several architectural alternatives for conventional binary routing networks are also evaluated. For example, the performance gains obtainable by using cut-through switching in the context of binary routing networks with small buffers are quantified. One surprising result is that networks constructed from nodes with more then two input and output ports can perform less well than those constructed from binary nodes. This result is quantified and explained     

Providing Fault-Tolerant Ad hoc Routing Service in Adversarial Environments

Most existing designs of ad hoc networks are based on the assumption of non-adversarial environments, where each node in the network is cooperative and well-behaved. When misbehaving nodes exist in the network, the performance of current routing protocols degrades significantly. Since ad hoc networks, consisting of autonomous nodes, are open and distributed in nature, maintaining a fault-free network environment is extremely difficult and expensive. In this paper, we propose a new routing service named best-effort fault-tolerant routing (BFTR). The design goal of BFTR is to provide packet routing service with high delivery ratio and low overhead in presence of misbehaving nodes. Instead of judging whether a path is good or bad, i.e., whether it contains any misbehaving node, BFTR evaluates the routing feasibility of a path by its end-to-end performance (e.g. packet delivery ratio and delay). By continuously observing the routing performance, BFTR dynamically routes packets via the most feasible path. BFTR provides an efficient and uniform solution for a broad range of node misbehaviors with very few security assumptions. The BFTR algorithm is evaluated through both analysis and extensive simulations. The results show that BFTR greatly improves the ad hoc routing performance in the presence of misbehaving nodes.     

Multihop sensor network design for wide-band communications

This paper presents a master/slave cellular-based mobile ad hoc network architecture for multihop multimedia communications. The proposed network is based on a new paradigm for solving the problem of cluster-based ad hoc routing when utilizing existing wireless local area network (WLAN) technologies. The network architecture is a mixture of two different types of networks: infrastructure (master-and-slave) and ad hoc. In this architecture, the participating slave nodes (SNs) in each cluster communicate with each other via their respective master nodes (MNs) in an infrastructure network. In contrast to traditional cellular networks where the base stations are fixed (e.g., interconnected via a wired backbone), in this network the MNs (e.g., base stations) are mobile; thus, interconnection is accomplished dynamically and in an ad hoc manner. For network implementation, the IEEE 802.11 WLAN has been deployed. Since there is no stationary node in this network, all the nodes in a cluster may have to move together as a group. However, in order to allow a mobile node to move to another cluster, which requires changing its point of attachment, a handoff process utilizing Mobile IP version 6 (IPv6) has been considered. For ad hoc routing between the master nodes (i.e., MNs), the Ad hoc On-demand Distance Vector (AODV) Routing protocol has been deployed. In assessing the network performance, field test trials have been carried out to measure the proposed network performance. These measurements include packet loss, delays under various test conditions such as a change of ad hoc route, handoffs, etc.     

Joint multi-cost routing and power control in wireless ad hoc networks

In this work we study the combination of multi-cost routing and adjustable transmission power in wireless ad hoc networks, so as to obtain dynamic energy- and interference-efficient routes to optimize network performance. In multi-cost routing, a vector of cost parameters is assigned to each network link, from which the cost vectors of candidate paths are calculated. Only at the end these parameters are combined in various optimization functions, corresponding to different routing algorithms, for selecting the optimal path. The multi-cost routing problem is a generalization of the multi-constrained problem, where no constraints exist, and is also significantly more powerful than single-cost routing. Since energy is an important limitation of wireless communications, the cost parameters considered are the number of hops, the interference caused, the residual energy and the transmission power of the nodes on the path; other parameters could also be included, as desired. We assume that nodes can use power control to adjust their transmission power to the desired level. The experiments conducted show that the combination of multi-cost routing and adjustable transmission power can lead to reduced interference and energy consumption, improving network performance and lifetime.     

The Impact of Deployment Pattern and Routing Scheme on the Lifetime in Multi-Sink Wireless Sensor Network

Extensive use of sensor and actuator networks in many real-life applications introduced several new performance metrics at the node and network level. Since wireless sensor nodes have significant battery constraints, therefore, energy efficiency, as well as network lifetime, are among the most significant performance metrics to measure the effectiveness of given network architecture. This work investigates the performance of an event-based data delivery model using a multipath routing scheme for a wireless sensor network with multiple sink nodes. This routing algorithm follows a sink initiated route discovery process with the location information of the source nodes already known to the sink nodes. It also considers communication link costs before making decisions for packet forwarding. Carried out simulation compares the network performance of a wireless sensor network with a single sink, dual sink, and multi sink networking approaches. Based on a series of simulation experiments, the lifetime aware multipath routing approach is found appropriate for increasing the lifetime of sensor nodes significantly when compared to other similar routing schemes. However, energy-efficient packet forwarding is a major concern of this work; other network performance metrics like delay, average packet latency, and packet delivery ratio are also taken into the account.

     

Adaptive alternate routing in WDM networks and its performance tradeoffs in the presence of wavelength converters

Routing in wavelength-routed all-optical WDM networks has received much attention in the past decade, for which fixed and dynamic routing methods have been proposed. Taking into account the observation that wavelength-routed all-optical WDM networks are similar to circuit-switched voice networks, except with regard to wavelength conversion, we propose an adaptive alternate routing (AAR) scheme for wavelength-routed all-optical WDM networks. A major benefit of AAR is that it can operate and adapt without requiring an exchange of network status, i.e., it is an information-less adaptive routing scheme. The scope of this work is to understand this scheme in its own right since no other dynamic routing schemes are known to have the information-less property. In this paper, we conduct a systematic study of AAR with regard to factors such as the number of converters, load conditions, traffic patterns, network topologies, and the number of alternate paths considered. We observe that the routing scheme with multiple alternate routes provides more gain at a lower load instead of requiring any nodes to be equipped with wavelength converters. On the other hand, the availability of wavelength converters at some nodes, along with adaptive routing, is beneficial at a moderate to high load without requiring all nodes to be equipped with wavelength converters. We also observed that a small number of alternate routes considered in a network without wavelength converters gives a much better performance than a network with full wavelength converters and fewer alternate routes. Throughout this study, we observed that the proposed adaptive alternate routing scheme adapts well to the network traffic condition.     

BeamStar: An Edge-Based Approach to Routing in Wireless Sensor Networks

Current expectations on sensor node in terms of size, cost, and energy efficiency have led to a severely limited design space on hardware and software. In this paper, we explore capabilities at the network edge for sensor networks, aiming to reduce the hardware and software complexity of a sensor node without sacrificing network performance. We present a novel edge-based routing protocol, nicknamed BeamStar, for wireless sensor networks. Under BeamStar, the base station exploits some nice properties associated with directional antenna and power control at the base station. We devise a simple protocol so that each sensor node can determine its location information passively with minimum control overhead. We also show how to design a robust routing protocol based on the location information at each sensor node. Under the proposed protocol, sensor nodes are relieved of the activities (or burdens) that are associated with control and routing, thus enabling much simpler hardware and software implementation at sensor nodes. Simulation results demonstrate that BeamStar achieves high reliability at comparable energy consumptions as compared with prior work. It is a viable approach to pursue size and cost reduction for future sensor node design.     

Single-path routing for life time maximization in multi-hop wireless networks

Energy-aware routing is important in multi-hop wireless networks that are powered by battery, e.g., wireless sensor networks. To maximize the network survivability, the energy efficiency of paths must be taken into account for route selection. Simple heuristics such as choosing paths with minimal energy consumption are ineffective, because the energy of the nodes on such paths may deplete quickly. The issue is particularly serious for the networks with regular traffic pattern as in monitoring sensor applications. Existing solutions to this issue typically adopt the multi-path routing approach, in which multiple paths are set up between source and destination and one (or all) of the paths is (are) used at a certain moment. However, this approach involves high overhead for establishment and management of multiple paths. In this paper, we present a static single-path routing scheme which uses one energy-efficient path for each communicating peer throughout the network lifetime, eliminating the overhead of multi-path routing. It is theoretically proved that our routing scheme achieves a constant factor approximate of the optimal solution. We compare the performance of the proposed scheme with that of multi-path routing via simulations. Despite the use of single static path, the proposed scheme outperforms existing multi-path routing schemes and produces performance close to the optimal multi-path solution, particularly in heavily loaded networks and multiple-gateway networks.     

Secured Self Organizing Network Architecture in Wireless Personal Networks

Secured self organizing network is an approach to computer network architecture that seeks to address the technical issues in heterogeneous networks that may lack continuous network connectivity. In delay tolerant network packets storage exists when there is any link breakage between the nodes in the network so delay is tolerable in this type of network during the data transmission. But this delay is not tolerable in wireless network for voice packet transmission. This evokes the use of wireless networks. In a network, different wireless network topologies are interoperating with each other so the communication across the network is called overlay network. This network is vulnerable to attacks due to mobile behaviour of nodes and frequent changes in topologies of the network. The attacks are wormhole attack and blackhole attack is analysed in this paper. They are critical threats to normal operation in wireless networks which results in the degradation of the network performance. The proposed recovery algorithm for wormhole and the isolation of blackhole will increase the performance of the network. The performance metrics such as throughput, packet delivery ratio, end–end delay and routing overhead of the network are evaluated.

     

A Distributed Message-passing Approach for Clustering Cognitive Radio Networks

Forming collaborative wireless network clusters in dynamically changing environments is essential for cognitive radios to achieve such desired objectives as interference resilience and low communications overhead. In this paper, a novel approach to form efficient node clusters in an ad hoc cognitive radio network (CRN) is introduced based on the affinity propagation (AP) message-passing technique. With this approach, nodes exchange messages containing local network information with their direct neighbours until a high quality set of clusterheads and an efficient cluster structure emerges. The groupings are based on measures of similarity between the network nodes, which are selected based on application requirements. As an initial application, we show how the AP technique can be used to distributively determine cluster assignments and elect a small number of clusterheads that cover a CRN. Such an objective is commonly used to reduce communication overhead in key network functions such as resource management and routing table maintenance. To demonstrate the merits of the proposed approach, the clustering efficiency of the AP technique is evaluated on randomly generated open spectrum access scenarios. The simulation results demonstrate that the proposed approach provides a smaller number of clusters than a standard technique based on approximating the minimum dominating sets of the corresponding ad hoc network graphs.     

RBR: a region-based routing protocol for mobile nodes in hybrid ad hoc networks

In hybrid ad hoc networks, mobile nodes can communicate not only with each other in a self-organizing manner, but also with nodes on wired networks for extensive information retrieval and dissemination. In this article we consider efficient routing operations between any two nodes in an ad hoc network that is linked to wired networks by an access point. To build routes with low routing overhead efficiently, we develop a new routing scheme of region-based routing (RBR), which utilizes hop counts between mobile nodes and the access point to localize a route discovery within a limited topological region. Limiting the region of route discovery results in fewer routing messages and therefore reduces routing overhead. Simulation results show that the RBR scheme greatly reduces routing overhead while preserving a high rate of success for route discovery to the destination     

Clustered Zigbee networks with data fusion: Characterization and performance analysis

In this paper, we analyze the performance of clustered Zigbee wireless sensor networks (WSNs) with data fusion. Performance indicators at both physical (probability of decision error) and network (network transmission rate, throughput, aggregate throughput, delay, and network lifetime) layers are considered. Data fusion is carried out at the access point (AP) and, in clustered configurations, also at the clusterheads, which act as intermediate fusion centers (FCs). The goal of this paper is to shed light on the joint impact of topology and data fusion on the network performance. The presented results, mainly obtained through Opnet-based simulations, show clearly that the operational point of a Zigbee WSN with data fusion lies over a characteristic multi-dimensional surface, whose shape remains the same regardless of the number of nodes in the network. The existence of this peculiar surface highlights fundamental performance trade-offs in Zigbee networks.     

EAOMDV-MIMC: A Multipath Routing Protocol for Multi-Interface Multi-Channel Mobile Ad-Hoc Networks

Multipath routing has been proposed to improve performance of mobile ad-hoc networks (MANETs). However, due to: (1) nodes lacking of network interface and (2) route coupling, using multiple paths concurrently in conventional single channel MANETs rarely exhibit performance gain. To improve performance, an ad-hoc routing protocol (and its extension) that utilizes multiple homogeneous network interface is proposed in this paper. Unlike other related multi-channel routing protocols, channels are not assigned. Instead, nodes are allowed to make use of all available channels they are tuned to. In the base protocol, nodes estimate channel conditions by monitoring their network interface queues and distribute data packets to different channels and next-hops according to their conditions. In the extended protocol, estimated channel condition at a node is further propagated to neighboring nodes by piggybacking channel condition information in data packets. With overhearing, other nodes can retrieve this information to make better next-hop selections. Extensive simulation studies show that our protocol outperforms other related multi-channel routing protocols.     

Ariadne: A Secure On-Demand Routing Protocol for Ad Hoc Networks

An ad hoc network is a group of wireless mobile computers (or nodes), in which individual nodes cooperate by forwarding packets for each other to allow nodes to communicate beyond direct wireless transmission range. Prior research in ad hoc networking has generally studied the routing problem in a non-adversarial setting, assuming a trusted environment. In this paper, we present attacks against routing in ad hoc networks, and we present the design and performance evaluation of a new secure on-demand ad hoc network routing protocol, called Ariadne. Ariadne prevents attackers or compromised nodes from tampering with uncompromised routes consisting of uncompromised nodes, and also prevents many types of Denial-of-Service attacks. In addition, Ariadne is efficient, using only highly efficient symmetric cryptographic primitives.