Particle swarm optimization based clustering algorithm with mobile sink for WSNs

Wireless sensor networks with fixed sink node often suffer from hot spots problem since sensor nodes close to the sink usually have more traffic burden to forward during transmission process. Utilizing mobile sink has been shown as an effective technique to enhance the network performance such as energy efficiency, network lifetime, and latency, etc. In this paper, we propose a particle swarm optimization based clustering algorithm with mobile sink for wireless sensor network. In this algorithm, the virtual clustering technique is performed during routing process which makes use of the particle swarm optimization algorithm. The residual energy and position of the nodes are the primary parameters to select cluster head. The control strategy for mobile sink to collect data from cluster head is well designed. Extensive simulation results show that the energy consumption is much reduced, the network lifetime is prolonged, and the transmission delay is reduced in our proposed routing algorithm than some other popular routing algorithms.     

Multi-constraint multi-objective QoS aware routing heuristics for query driven sensor networks using fuzzy soft sets

In this paper, a fuzzy based distributed power aware routing scheme considering both energy and bandwidth constraints, especially for query driven applications in the asynchronous duty-cycled wireless sensor networks are devised. The proposed multi-constraint, multi-objective routing optimization approach under strict resource constraints guarantees reliability and fast data delivery along with efficient power management in spite of unreliable wireless links and limited power supply. In query driven applications, the request from the sink to the individual sensor node will be a broadcast message, whereas the individual sensor nodes replies back to sink as unicast messages. In the proposed work, the fuzzy approach and “A Star” algorithm are utilized for satisfying energy and bandwidth constraints to route the broadcast messages of the sink while querying all the sensor nodes in the network. Every node will be provided with a guidance list, which is used to decide the next best neighbor node with good route quality for forwarding the received multi-hop broadcast messages. The route quality of the every node is estimated with fuzzy rules based on the network parameters such as maximum remaining energy, minimum traffic load and better link quality to increase the network lifetime. The provision of overhearing the broadcast messages and acknowledgements within the transmission range minimizes the effort to search for the active time of nodes while routing the broadcast messages with asynchronous scheduling. Further, in the proposed work only the time slot of its nearest neighbor relay node (to which packets are to be forwarded) is learnt to reduce the number of message transmissions in the network. For the unicast message replies, the fuzzy membership function is modified and devised based on the routing metrics such as higher residual energy, minimum traffic loads and minimum hop count under energy and bandwidth constraints. Also, the multi-hop heuristic routing algorithm called Nearest Neighbor Tree is effectively used to reduce the number of neighbors in the guidance list that are elected for forwarding. This helps to increase the individual sensor node’s lifetime, thereby maximizes the network lifetime and guarantees increased network throughput. The simulation results show that the proposed technique reduces repeated transmissions, decreases the number of transmissions, shortens the active time of the sensor nodes and increases the network lifetime for query driven sensor network applications invariant to total the number of sensor nodes and sinks in the network. The proposed algorithm is tested in a small test bed of sensor network with ten nodes that monitors the room temperature.     

WSN in cyber physical systems: Enhanced energy management routing approach using software agents

Recently, the cyber physical system has emerged as a promising direction to enrich the interactions between physical and virtual worlds. Meanwhile, a lot of research is dedicated to wireless sensor networks as an integral part of cyber physical systems. A wireless sensor network (WSN) is a wireless network consisting of spatially distributed autonomous devices that use sensors to monitor physical or environmental conditions. These autonomous devices, or nodes, combine with routers and a gateway to create a typical WSN system. Shrinking size and increasing deployment density of wireless sensor nodes implies the smaller equipped battery size. This means emerging wireless sensor nodes must compete for efficient energy utilization to increase the WSN lifetime. The network lifetime is defined as the time duration until the first sensor node in a network fails due to battery depletion. One solution for enhancing the lifetime of WSN is to utilize mobile agents. In this paper, we propose an agent-based approach that performs data processing and data aggregation decisions locally i.e., at nodes rather than bringing data back to a central processor (sink). Our proposed approach increases the network lifetime by generating an optimal routing path for mobile agents to transverse the network. The proposed approach consists of two phases. In the first phase, Dijkstra’s algorithm is used to generate a complete graph to connect all source nodes in a WSN. In the second phase, a genetic algorithm is used to generate the best-approximated route for mobile agents in a radio harsh environment to route the sensory data to the base-station. To demonstrate the feasibility of our approach, a formal analysis and experimental results are presented.     

一种基于非均匀分簇的无线传感器网络路由协议

在路由协议中利用分簇技术可以提高无线传感器网络的可扩展性.当簇首以多跳通信的方式将数据传输至数据汇聚点时,靠近汇聚点的簇首由于转发大量数据而负载过重,可能过早耗尽能量而失效,这将导致网络分割.该文提出一种新颖的基于非均匀分簇的无线传感器网络多跳路由协议.它的核心是一个用于组织网络拓扑的能量高效的非均匀分簇算法,其中候选簇首通过使用非均匀的竞争范围来构造大小不等的簇.靠近汇聚点的簇的规模小于远离汇聚点的簇,因此靠近汇聚点的簇首可以为簇间的数据转发预留能量.模拟实验结果表明,该路由协议有效地平衡了簇首的能量消耗,并显著地延长了网络的存活时间.     

可充电无线传感网络能量均衡路由算法

针对可充电无线传感网络中的能量均衡路由问题,提出在稳定功率无线充电和监测数据收集网络场景下的多路径路由算法和机会路由算法,以实现网络的能量均衡。首先,通过电磁传播理论构建了无线传感节点的充电和接收功率关系模型;然后,考虑网络中无线传感节点的发送能耗和接收能耗,基于上述充电模型将网络能量均衡的路由问题转化为网络节点运行时间的最大最小化问题,通过线性规划得到的各链路流量用以指导路由中数据流量分配;最后,考虑一种更加现实的低功耗的场景,并提出了一种基于机会路由的能量均衡路由算法。实验结果表明,与最短路径路由（SPR）和期望周期最短路由（EDC）算法相比较,所提出的两种路由算法均能有效提高采集能量的利用率和工作周期内的网络生命周期。     

能量高效的无线传感器网络路由协议

针对目前无线传感器网络分簇路由协议存在的节点能耗不均衡的问题,提出一种基于分簇思想的能量高效的多跳路由协议(EEMR)。该协议首先基于节点临近度将网络划分成簇,采用簇首自适应轮转模式优化簇内节点通信的能量消耗,以高剩余能量短路径向心角的适应度路由算法均衡簇间通信负载和能量消耗,有效避免多跳路由中出现的能量消耗不均衡问题。仿真结果表明,EEMR协议能有效均衡网络内节点的能量消耗,显著延长无线传感器网络的生命期并提高网络能量利用率。     

一种协作和中继混合的传感网寿命最大化路由算法

周期性监控、多对一数据传输是无线传感网的典型场景之一.其中存在固有的能耗不均问题,即与sink 节点距离不同的节点能耗差异大,严重缩短了网络寿命.提出了一种基于协作和中继混合传输模式的路由方法,利用协作和中继在远、近距离传输时能耗的互补性,通过调整节点采用中继模式传输的负载比例(称为中继率),均衡节点间的能耗,延长网络寿命.定量地描述了节点能耗和中继率的关系,将网络寿命最大化建模为关于中继率矢量的高阶非线性优化问题.为了求解该问题,深入分析了寿命最大化时节点间能耗的关系,得到的结论是：若以中继模式传输单比特的能耗小于sink 一跳邻节点的协作模式能耗,则寿命最大化时所有节点能耗相等;否则,寿命最大化时节点中仅满足协作模式能耗大于中继模式的部分节点能耗相等.由此将多元非线性的网络寿命最大化问题转化为关于单变量的优化问题,求得了最优中继率.利用理论分析结果设计了分布式路由算法DORRCR.仿真结果表明,该算法能够有效延长网络寿命,显著提高全网的能耗均衡性.     

Dynamic cluster head for lifetime efficiency in WSN

Saving energy and increasing network lifetime are significant challenges in wireless sensor networks （WSNs）. In this paper, we propose a mechanism to distribute the responsibility of cluster-heads among the wireless sensor nodes in the same cluster based on the ZigBee standard, which is the latest WSN standard. ZigBee supports ad hoc on-demand vector （AODV） and cluster-tree routing protocols in its routing layer. However, none of these protocols considers the energy level of the nodes in the network establishing process or in the data routing process. The cluster-tree routing protocol supports single or multi-cluster networks. However, each single cluster in the multi-cluster network has only one node acting as a cluster head. These cluster-heads are fixed in each cluster during the network lifetime. Consequently, using these cluster-heads will cause them to die quickly, and the entire linked nodes to these cluster-heads will be disconnected from the main network. Therefore, the proposed technique to distribute the role of the cluster head among the wireless sensor nodes in the same cluster is vital to increase the lifetime of the network. Our proposed technique is better in terms of performance than the original structure of these protocols. It has increased the lifetime of the wireless sensor nodes, and increased the lifetime of the WSN by around 50% of the original network lifetime.     

SEEM: Secure and energy-efficient multipath routing protocol for wireless sensor networks

A Wireless Sensor Network (WSN) is a collection of wireless sensor nodes forming a temporary network without the aid of any established infrastructure or centralized administration. In such an environment, due to the limited range of each node’s wireless transmissions, it may be necessary for one sensor node to ask for the aid of other sensor nodes in forwarding a packet to its destination, usually the base station. One important issue when designing wireless sensor network is the routing protocol that makes the best use of the severely limited resource presented by WSN, especially the energy limitation. Another import factor required attention from researchers is providing as much security to the application as possible. The proposed routing protocols in the literature focus either only on increasing lifetime of network or only on addressing security issues while consuming much power. None of them combine solutions to the two challenges. In this paper, we propose a new routing protocol called SEEM: Secure and Energy-Efficient multipath Routing protocol. SEEM uses multipath alternately as the path for communicating between two nodes thus prolongs the lifetime of the network. On the other hand, SEEM is effectively resistive to some specific attacks that have the character of pulling all traffic through the malicious nodes by advertising an attractive route to the destination. The performance of our protocol is compared to the Directed Diffusion protocol. Simulation results show that our protocol surpasses the Directed Diffusion protocol in terms of throughput, control overhead and network lifetime.     

基于簇的无线传感器网络交会路由协议

针对现有无线传感器网络(WSN)协议中更多消耗sink附近节点能量导致网络寿命短的问题,本文提出一种基于簇的无线传感器网络交会路由协议(Cluster-based Rendezvous Routing Protocol, CRRP)。该协议是基于交会的路由协议,其中在网络的中间构建交会区域,该交会区域划分整个网络区域并在传感器节点之间分配网络负载,这延长了网络寿命。此交会区域内的节点分为不同的簇,每个簇的簇头(CH)负责不同簇之间的通信,sink在此交会区域内发送其更新的位置信息,并且当传感器节点想要发送数据时,会从该交会区域检索sink的当前位置信息并直接将数据发送到sink。仿真实验结果表明,在能耗与网络寿命性能方面,本文CRRP协议优于Rendezvous协议、LBDD协议、Railroad协议和Ring协议。     

An improved ant colony optimization-based approach with mobile sink for wireless sensor networks

Traditional wireless sensor networks (WSNs) with one static sink node suffer from the well-known hot spot problem, that of sensor nodes near the static sink bear more traffic load than outlying nodes. Thus, the overall network lifetime is reduced due to the fact some nodes deplete their energy reserves much faster compared to the rest. Recently, adopting sink mobility has been considered as a good strategy to overcome the hot spot problem. Mobile sink(s) physically move within the network and communicate with selected nodes, such as cluster heads (CHs), to perform direct data collection through short-range communications that requires no routing. Finding an optimal mobility trajectory for the mobile sink is critical in order to achieve energy efficiency. Taking hints from nature, the ant colony optimization (ACO) algorithm has been seen as a good solution to finding an optimal traversal path. Whereas the traditional ACO algorithm will guide ants to take a small step to the next node using current information, over time they will deviate from the target. Likewise, a mobile sink may communicate with selected node for a relatively long time making the traditional ACO algorithm delays not suitable for high real-time WSNs applications. In this paper, we propose an improved ACO algorithm approach for WSNs that use mobile sinks by considering CH distances. In this research, the network is divided into several clusters and each cluster has one CH. While the distance between CHs is considered under the traditional ACO algorithm, the mobile sink node finds an optimal mobility trajectory to communicate with CHs under our improved ACO algorithm. Simulation results show that the proposed algorithm can significantly improve wireless sensor network performance compared to other routing algorithms.     

无线传感网中一种智能数据融合算法的实现及仿真分析

在无线传感网中,传感器节点一般都由自身装配的电池供电,难以进行电量补充,因此节约电量对于无线传感网来说至关重要.为了提高无线传感网能量使用效率,延长网络生存时间,提出了一种结合遗传算法和粒子群算法优化BP神经网络的智能数据融合算法 GAPSOBP(BP Neural Network Data Fusion algorithm optimized by Genetic algorithm and Particle swarm).GAPSOBP算法将无线传感网的节点类比为BP神经网络中的神经元,通过神经网络提取无线传感网采集的感知数据并结合分簇路由对收集的传感数据进行融合处理,从而大幅减少发往汇聚节点的网络数据量.仿真结果表明,与经典LEACH算法和PSOBP算法相比,GAPSOBP算法能有效减少网络通信量,节约节点能量,显著延长网络生存时间.     

An enhanced real-time routing protocol with load distribution for mobile wireless sensor networks

Mobile wireless sensor network (MWSN) is a wireless ad hoc network that consists of a very large number of tiny sensor nodes communicating with each other in which sensor nodes are either equipped with motors for active mobility or attached to mobile objects for passive mobility. A real-time routing protocol for MWSN is an exciting area of research because messages in the network are delivered according to their end-to-end deadlines (packet lifetime) while sensor nodes are mobile. This paper proposes an enhanced real-time with load distribution (ERTLD) routing protocol for MWSN which is based on our previous routing protocol RTLD. ERTLD utilized corona mechanism and optimal forwarding metrics to forward the data packet in MWSN. It computes the optimal forwarding node based on RSSI, remaining battery level of sensor nodes and packet delay over one-hop. ERTLD ensures high packet delivery ratio and experiences minimum end-to-end delay in WSN and MWSN compared to baseline routing protocol. In this paper we consider a highly dynamic wireless sensor network system in which the sensor nodes and the base station (sink) are mobile. ERTLD has been successfully studied and verified through simulation experiment.     

基于贪婪算法无线传感器网络中继节点布局的研究

为实现远距离的无线通信, 在网络中添加中继节点, 采用多跳路由传输数据。对于中继节点的布局问题, 依据线性结构使网络整体能量消耗最小的特征, 提出一种中继节点贪婪布局算法。该算法通过最近贪婪策略、中继节点通信容量、传感器节点数据转发跳数等约束方法限制中继节点的布局位置。理论分析和实验验证了该算法能够有效减少能量消耗, 延长网络寿命。     

基于蚁群的无线传感网最大化生存时间路由

为提高无线传感网的生存时间,对基于蚁群算法的最大化生存时间路由(MLRAC)进行了研究。该路由利用链路能耗模型和节点发送数据概率,计算一个数据收集周期内节点总能耗。同时考虑节点初始能量,建立了最大化生存时间路由的最优模型。为求解该最优模型,在经典蚁群算法的基础上,提出修正的蚁群算法。该算法采用新的邻居节点转发概率公式、信息素更新公式和分组探测方法,经过一定的迭代计算获得网络生存时间的最优值和每个节点的最优发送数据概率。最后,Sink节点洪泛通知网络中所有节点。节点根据接收到的最优概率,选择数据分组未经过的邻居节点发送数据。仿真实验表明,经过一定时间的迭代,MLRAC的生存时间可以收敛到最优值。该算法能延长网络生存时间,在一定的条件下,MLRAC算法比PEDAP、LET、Ratio-w、Sum-w等算法更优。     

一种基于虚拟网格位置的分簇算法

为了延长无线传感器网络生命周期, 提出一种基于虚拟网格的分簇路由算法RPLG. 该算法将监测区域划分为若干虚拟网格, 同一网格内节点自组织成簇. 根据节点所在网格位置和剩余能量启动计时器选取本地簇首, 且簇内成员可以根据局部的信息调整簇的大小, 达到节省能量的目的. 仿真实验和分析表明: 该协议能均衡网络能量, 延长网络的生存时间.     

带有重叠区域的多跳非均匀分簇路由算法

能耗作为衡量无线传感器网络性能的一项重要指标,通常将延长生命周期、均衡能耗作为网络协议重要的设计目标.针对静态、异构、非均匀分布的网络模型,设计带有重叠区域的分簇及簇内单跳、簇间多跳的路由算法 ----- OMU分簇路由算法,该算法中簇头不再作为数据转发节点,而主要用于簇内数据的接收与融合.通过综合考虑节点剩余能量、节点密度及与基站的距离进行簇头选举并进行分簇,形成簇间重叠区域,产生用于数据转发的中继节点.同时,建立簇头与中继节点轮换机制以达到节点能耗均衡的目的,并为每个节点建立能量最省的多跳数据传输路径.仿真结果表明,所设计的分簇路由算法,特别是在大规模部署的无线传感器网络中,能有效减少和均衡能量消耗.     

Lifetime elongation for wireless sensor network using queue-based approaches

A wireless sensor network (WSN) is envisioned as a cluster of tiny power-constrained devices with functions of sensing and communications. Sensors closer to a sink node have a larger forwarding traffic burden and consume more energy than nodes further away from the sink. The whole lifetime of WSN is deteriorated because of such an uneven node power consumption patterns, leading to what is known as an energy hole problem (EHP). From open literatures, most research works have focused on how to optimally increase the probability of sleeping states using various wake-up strategies. In this article, we propose a novel power-saving scheme to alleviate the EHP based on the N-policy M/M/1 queuing theory. With little or no extra management cost, the proposed queue-based power-saving technique can be applied to prolong the lifetime of the WSN economically and effectively. A mathematical analysis on the optimal control parameter has been made in detail. Focusing on many-to-one WSN, numerical and network simulation results validate that the proposed approach indeed provides a feasibly cost-effective approach for lifetime elongation of WSN.     

移动社会网络中社会性路由算法研究

在无法部署Sink的无线传感器网络中, 数据采集者(即:能够收集数据的人或移动设备)在网络的任意位置收集数据, 即泛在数据收集。网络区域中的节点数量庞大, 能量有限, 如何能有效地采集到全部节点的数据是一个难点。提出一个网络生命周期最大化的泛在数据收集协议MULAC。MULAC以用户所在当前位置为圆心, 半径为r的区域内选择一个节点v。以v为根构造一棵最大化生命周期树T。网络中的节点可以通过T传送数据给v, 数据采集者可以通过v接收到网络中的全部数据。当数据采集者移动到其他位置, T将根据用户新的位置改变根节点, 并且以最小的能量耗费调整树结构, 从而延长全网的寿命。在收集数据过程中保证无线传感器网络生命周期最大化是一个NP完全问题, MULAC能够近似最优的解决此问题。仿真实验和理论分析表明, MULAC能有效延长网络生命周期。