无线传感器网络功率路由算法研究

无线传感器网络的应用越来越广泛,主要是军事、工业、医疗等方面。然而无线传感器网络具有节点能量、存储和计算能力非常有限等特点,文中在传统的LEACH（低功耗自适应集簇分层型）协议的基础上进行了改进,并提出了一种新的无线传感器网络路由算法LEACH-N。新算法沿用了LEACH协议簇的结构,在簇头选择方法上基于传统DCHS算法的簇头选择算法,簇内成员与簇头之间直接通信,簇头与基站之间轮流进行单跳和多跳通信;多跳通信则是采用一种改进的MTE（最小传输能量）路由算法。通过NS2仿真软件对LEACH-N协议与LEACH协议分别进行了性能测试。实验结果表明,相比LEACH协议,LEACH—N协议系统能耗低、网络生命周期长,且具有更好的规模可扩展性。     

基于双簇头非均匀分簇的LEACH协议的改进

在无线传感器网络中的LEACH协议是一种自适应聚类路由算法．由于LEACH协议存在着无法控制簇首在网络中的分布位置、簇首选择方式限制条件不够等缺点导致能量消耗太大．基于簇头能量限制和双簇头路由方式,对LEACH协议进行了改进,设计了一种降低能耗的双簇头非均匀分簇路由协议．双簇头非均匀分簇路由协议采用NS2进行网络仿真实验,通过仿真结果的分析以及与LEACH协议的对比,证明双簇头非均匀分簇路由协议有效提高了网络能耗的均衡性．     

无线传感器网络LEACH协议的研究与改进

无线传感器网络(WSN)的数据传输不能与路由协议分离,高效的能量传输是无线传感器网络中最重要的因素之一。针对LEACH簇头分布的不均匀以及与基站距离的不同,提出了一种改进的LEACH算法,该算法考虑剩余能量和最优簇头,与现有的LEACH协议相比,该协议降低了能耗。     

无线传感器网络LEACH路由协议的簇头多跳算法

LEACH路由协议作为无线传感器网络常用的一种路由协议,存在簇头分布不均、网络拓扑及能量消耗不均衡等问题,不能有效的降低无线传感器网络的节能能耗和延长网络生存时间。针对这些问题,在LEACH协议基础上发展出一种新的协议---簇头多跳算法。     

基于最优簇头数和三段路由的改进型LEACH算法

LEACH协议可延长无线传感器网络的使用寿命,提高信息传输量.但是研究发现基站距离网络区域愈远,LEACH协议的效果愈差,网络价值愈小.故本文提出了一种基于最优簇头数和三段路由的改进型LEACH算法,以克服基站位置对网络寿命和信息传输量的影响.该算法依据不同WSN的传感器节点数目,预先计算出理论上最优的簇头数目,残余能量最高的簇头将被选举为唯一的高层簇头,形成节点—簇头—高层簇头—基站的三段数据路由.实验结果表明,与LEACH协议相比,当传输距离小于距离阈值时,该算法有效提升了节点能耗的均衡性,推迟首节点死亡时间,从而提高信息传输量;当距离超过阈值后,网络寿命和信息传输量显著提高,算法优势更为明显.     

一种WSN中分簇路由算法的改进

在无线传感器网络中,基于分簇的路由协议对提高网络的寿命有着重要作用,LEACH是一种应用比较广泛的层次路由协议。本文提出一种新的基于最优分簇的无线传感器网络分簇路由（LEACH-O）算法,在簇的形成过程考虑到节点的集中程度和节点的剩余能量,从而减少传感器节点的能量消耗,优化资源利用率。仿真实表明,与传统的LEACH算法相比,该算法配传感器节点间数据传输提供了高效路由,从而延长网络的生命周期。     

一种基于蚁群优化的分簇路由算法

在无线传感器网络路由协议的研究中,能量高效是其首要设计目标.传统LEACH协议产生簇头数目比较随机,并且簇头直接与基站通信导致能量消耗过快.在分析传统和改进LEACH路由协议的基础上,提出了一种簇头数目固定的簇头选择机制,解决了簇头分布不均匀的问题.并且将蚁群优化算法应用到无线传感器网络的路径选择中,利用蚁群的动态适应性和寻优能力,在簇头与基站之间形成一条最优路径进行通信.在Matlab平台下对新提出的算法进行仿真测试实验,实验结果表明,相对于LEACH路由协议,该算法降低了平均能量消耗,延长了网络的生命周期.     

基于能量均衡的LEACH改进协议

能量有限性是无线传感器网络（WSN）的最重要的特性,在网络路由算法中也是优先考虑的一个主要因素。LEACH路由协议是无线传感器网络中被广泛应用的分层协议,但其簇头选取的随机性,不可避免的使该协议存在着簇头选择不合理,节点能耗不均衡的缺点。本文对一些LEACH的改进协议进行研究,在此基础上提出了一种新的LEACH改进协议,并通过理论分析证明了该协议的可靠性。     

无线传感器网络能量均衡分簇路由协议

LEACH是无线传感器网络(Wireless Sensor Network,WSN)中一种经典的分层式路由协议,在此基础上通过对LEACH成簇算法及簇间路由的改进,提出了一种新的均衡能量消耗分簇路由协议。该协议在无线传感器网络成簇过程中充分考虑了传感器节点的能量状态,同时簇首向基站的通信采用基于能量的簇间路由。理论分析及仿真结果表明,改进的协议能够均衡传感器节点的能量消耗,有效地延长网络寿命。     

基于分簇的无线传感器网络安全路由协议研究

无线传感器网络（Wireless Sensor Networks,简称WSNs）作为一种新的获取信息的方式和处理模式,已成为通信领域的研究重点。而路由协议则是无线传感器网络当前的热点研究之一。目前,针对较为典型的分簇式路由协议LEACH路由协议的研究,是无线传感器网络目前研究的一个热点。介绍了无线传感器网络路由协议常见的攻击类型,并从路由安全的角度建议性的提出了一种对LEACH路由协议针对安全性的改进方案,并应用NS2仿真平台,对改进协议做了仿真并进行了性能分析。     

Clustering‐based power‐controlled routing for mobile wireless sensor networks

This paper presents two new routing protocols for mobile sensor networks, viz. power‐controlled routing (PCR) and its enhanced version, i.e. Enhanced Power‐Controlled Routing (EPCR). In both the protocols, fixed transmission power is employed in the clustering phase but when ordinary nodes are about to send their data to their respective cluster‐heads, they change their transmission power according to their distance from their cluster‐head. While in PCR, the nodes are associated with the cluster‐head on the basis of weight, in EPCR it is done on the basis of distance. In addition to the protocols, we are suggesting a packet loss recovery mechanism for the PCR and EPCR. Both protocols work well for both mobile and static networks and are designed to achieve high network lifetime, high packet delivery ratio, and high network throughput. These protocols are extensively simulated using mass mobility model, with different speeds and different number of nodes to evaluate their performance. Simulation results show that both PCR and EPCR are successful in achieving their objectives by using variable transmission powers and smart clustering. Copyright © 2011 John Wiley & Sons, Ltd.     

Cluster‐based data dissemination,cluster head formation under sparse,and dense traffic conditions for vehicular ad hoc networks

Information and communication technologies have changed the way of operations in all fields. These technologies also have adopted for wireless communication and provide low cost and convenient solutions. Vehicular ad hoc networks are envisioned with their special and unique intercommunication systems to provide safety in intelligent transportation systems and support large‐size networks. Due to dense and sparse traffic conditions, routing is always a challenging task to establish reliable and effective communication among vehicle nodes in the highly transportable environment. Several types of routing protocols have been proposed to handle high mobility and dynamic topologies including topology‐based routing, position and geocast routing, and cluster‐based routing protocols. Cluster‐based routing is one of the feasible solutions for vehicular networks due to its manageable and more viable nature. In cluster‐based protocols, the network is divided into many clusters and each cluster selects a cluster head for data dissemination. In this study, we investigate the current routing challenges and trend of cluster‐based routing protocols. In addition, we also proposed a Cluster‐based Routing for Sparse and Dense Networks to handle dynamic topologies, the high‐mobility of vehicle nodes. Simulation results show a significant performance improvement of the proposed protocol.     

Information Theoretic Analysis of Proactive Routing Overhead in Mobile Ad Hoc Networks

This paper considers basic bounds on the overhead of link-state protocols in mobile ad hoc networks. Hierarchical protocols are known for their good scalability properties, and hence this paper considers a two-level hierarchical protocol. In such protocols, nodes need to keep track of shortest path information, link states and cluster membership. Two types of overheads are considered; the memory needed to store routing-related information, including link-states and cluster membership, and the control messages that need to be exchanged to keep track of the changes in the network. Memory overhead is important practically for dimensioning network nodes, while message routing overhead is important since it reduces the effective capacity of the network to carry user data (vis-a-vis control data). The scalability properties of the message routing overhead are analyzed for different modes of network scaling. Practical implications, such as optimal cluster size, average/fixed memory requirement and routing protocol parameter selections are discussed.     

A cluster‐based fault‐tolerant routing protocol for wireless sensor networks

Energy conservation and fault tolerance are two critical issues in the deployment of wireless sensor networks (WSNs). Many cluster‐based fault‐tolerant routing protocols have been proposed for energy conservation and network lifetime maximization in WSNs. However, these protocols suffer from high frequency of re‐clustering as well as extra energy consumption to tolerate failures and consider only some very normal parameters to form clusters without any verification of the energy sufficiency for data routing. Therefore, this paper proposes a cluster‐based fault‐tolerant routing protocol referred as CFTR. This protocol allows higher energy nodes to become Cluster Heads (CHs) and operate multiple rounds to diminish the frequency of re‐clustering. Additionally, for the sake to get better energy efficiency and balancing, we introduce a cost function that considers during cluster formation energy cost from sensor node to CH, energy cost from CH to sink, and another significant parameter, namely, number of cluster members in previous round. Further, the proposed CFTR takes care of nodes, which have no CH in their communication range. Also, it introduces a routing algorithm in which the decision of next hop CH selection is based on a cost function conceived to select routes with sufficient energy for data transfer and distribute uniformly the overall data‐relaying load among the CHs. As well, a low‐overhead algorithm to tolerate the sudden failure of CHs is proposed. We perform extensive simulations on CFTR and compare their results with those of two recent existing protocols to demonstrate its superiority in terms of different metrics.     

MPMAC: Clustering Based MAC Protocol for VANETs

Wireless Personal Communications - Vehicular safety messaging is warranted mostly in turbulent traffic situations in which even cluster based MAC protocols are beset by problems of cluster rupture,...     

基于提前选择策略的传感器网络的分层路由协议

能量的有限性严重限制了无线传感器网络的发展,而数据冗余问题在分层路由协议中广泛存在,网络的密度越高,数据冗余问题越严重.现介绍一种新的方法来解决这个问题.在群建立之前从网络中选取一些已分配的节点,而这些操作类似于群首节点的选取过程,这些被选取的节点将用来完成整个网络的数据融合过程.仿真结果分析表明采用了这种策略之后网络生存期延长了很多.     

Multipath Security Aware Routing Protocol for MANET Based on Trust Enhanced Cluster Mechanism for Lossless Multimedia Data Transfer

The dynamic nature of mobile nodes of ad hoc network is mostly affected by security problems which reduce data forwarding rate in multimedia sources. Due to the rapid growth of wireless applications, the different multitalented routing protocols are proposed in recent years. But the recent protocols are not efficient for multimedia applications, till now, specific security aware routing protocols are not proposed for multimedia data transfers. In this paper, we proposed trust enhanced cluster based multipath routing (TECM) algorithm. We use energy efficient PSO algorithm used to create cluster formation and cluster head, super cluster head are selected from trust values, which compute form proposed TECM algorithm. The multi trust factors are used for trust computation, such as frame/packet loss ratio, frame/packet forward energy, frame/packet receiving energy, routing overhead, received signal strength, frame/packet forward rate, average forward delay and protocol deviation flag. We then combine proposed TECM algorithm with standard multipath OLSR protocol (TECM-OLSR) to analyze the performance of proposed algorithm. The simulated results show that proposed TECM-OLSR protocol is very effective in terms of loss and delivery rate, delay, routing overhead and network lifetime compare to FPNT-OLSR.     

Buses for Anonymous Message Delivery

Abstract. This work develops a novel approach to hide the senders and the receivers of messages. The intuition is taken from an everyday activity that hides the ``communication pattern'—the public transportation system. To describe our protocols, buses are used as a metaphor: Buses, i.e., messages, are traveling on the network, each piece of information is allocated a seat within the bus. Routes are chosen and buses are scheduled to traverse these routes. Deterministic and randomized protocols are presented, the protocols differ in the number of buses in the system, the worst case traveling time, and the required buffer size in a ``station.' In particular, a protocol that is based on cluster partition of the network is presented; in this protocol there is one bus traversing each cluster. The clusters' size in the partition gives time and communication tradeoffs. One advantage of our protocols over previous works is that they are not based on statistical properties for the communication pattern. Another advantage is that they only require the processors in the communication network to be busy periodically.     

Web presence transformations in the 1990s: an analysis of press releases

Many organizations are constantly changing their web presence. Despite the frequency of these redesigns, there appears to be little evidence to explain what kinds of changes are incorporated into each updated version of a web presence. To understand how commercial organizations transform their web presence, we conduct a content analysis and a cluster analysis of press releases describing redesign initiatives in the late 1990s. Findings suggest that the majority of companies redesigned their web presence to expand information and change navigation protocols. Surprisingly, the addition of interactive features such as online ordering and community communication channels is present in only 20% of the redesign cases studied. According to the groups provided by the cluster analysis, most of the changes reported in these press releases are centered on improving the usability of the web presence. Based on this evidence we conclude that initial transformations to commercial websites were more driven by the need to effectively communicate new information than by the addition of e-commerce features.     

A scalable and energy‐efficient MAC protocol for sensor and actor networks

A scalable energy‐efficient MAC protocol is proposed for wireless sensor and actor networks (WSAN) to improve the network performance. Actor's placement has computed using midpoint K‐mean technique. These actors perform as the cluster heads and collect the information from its members. Cluster head computes the shortest path to all of its cluster members. Further, it divides the cluster into multiple subtrees and assigns a noninterference channel to every subtree. A token is assigned to each subtree for intracluster communication. Token handling and token processing mechanisms are proposed to transfer token from one node to next eligible node. Finally, a throughput‐based channel selection mechanism has proposed for actor‐actor communication. The proposed protocol is simulated in NS2 and compared with its competitive MAC protocols. The results describe that the existing protocols are out beaten by the proposed mechanism.