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.     

小型化低功耗多媒体传感器网络节点设计

针对无线多媒体传感器网络及其性能特点,特别是在军事上的重要应用,以及当前无线多媒体传感器网络在能量、通信、计算和存储能力等方面还有待进一步完善,其节点芯片设计、三维场景的覆盖、智能多媒体信息处理和多媒体信息安全等还存在的问题,根据实验需要,设计并实现了小型化低功耗无线多媒体传感器网络节点的硬件平台,测试结果表明该设计满足指标要求。     

Security in wireless sensor networks

Recent advances in electronics and wireless communication technologies have enabled the development of large-scale wireless sensor networks that consist of many low-power, low-cost, and small-size sensor nodes. Sensor networks hold the promise of facilitating large-scale and real-time data processing in complex environments. Security is critical for many sensor network applications, such as military target tracking and security monitoring. To provide security and privacy to small sensor nodes is challenging, due to the limited capabilities of sensor nodes in terms of computation, communication, memory/storage, and energy supply. In this article we survey the state of the art in research on sensor network security.     

Collaborative sensor networking towards real-time acoustical beamforming in free-space and limited reverberance

Wireless sensor networks have been attracting increasing research interest given the recent advances in microelectronics, array processing, and wireless networking. Consisting of a large collection of small, wireless, low-cost, integrated sensing, computing and communicating nodes capable of performing various demanding collaborative space-time processing tasks, wireless sensor network technology poses various unique design challenges, particularly for real-time operation. We review the approximate maximum-likelihood (AML) method for source localization and direction-of-arrival (DOA) estimation. Then, we consider the use of least-squares method (LS) method applied to DOA bearing crossings to perform source localization. A novel virtual array model applicable to the AML-DOA estimation method is proposed for reverberant scenarios. Details on the wireless acoustical testbed are given. We consider the use of Compaq iPAQ 3760s, which are handheld, battery-powered device normally meant to be used as personal organizers (PDAs), as sensor nodes. The iPAQ provide a reasonable balance of cost, availability, and functionality. It has a build in StrongARM processor, microphone, codec for acoustic acquisition and processing, and a PCMCIA bus for external IEEE 802.11b wireless cards for radio communication. The iPAQs form a distributed sensor network to perform real-time acoustical beamforming. Computational times and associated real-time processing tasks are described. Field measured results for linear, triangular, and square subarrays in free-space and reverberant scenarios are presented. These results show the effective and robust operation of the proposed algorithms and their implementations on a real-time acoustical wireless testbed.     

The challenges of building mobile underwater wireless networks for aquatic applications

The large-scale mobile underwater wireless sensor network (UWSN) is a novel networking paradigm to explore aqueous environments. However, the characteristics of mobile UWSNs, such as low communication bandwidth, large propagation delay, floating node mobility, and high error probability, are significantly different from ground-based wireless sensor networks. The novel networking paradigm poses interdisciplinary challenges that will require new technological solutions. In particular, in this article we adopt a top-down approach to explore the research challenges in mobile UWSN design. Along the layered protocol stack, we proceed roughly from the top application layer to the bottom physical layer. At each layer, a set of new design intricacies is studied. The conclusion is that building scalable mobile UWSNs is a challenge that must be answered by interdisciplinary efforts of acoustic communications, signal processing, and mobile acoustic network protocol design.     

An efficient anonymous communication protocol for wireless sensor networks

Anonymous communication is very important for many wireless sensor networks, because it can be used to hide the identity of important nodes, such as the base station and a source node. In sensor networks, anonymous communication includes several important aspects, such as source anonymity, communication relationship anonymity, and base station anonymity. Existing sensor network anonymous schemes either cannot achieve all the anonymities or have large computation, storage, and communication overheads. In this paper, we propose an efficient anonymous communication protocol for sensor networks that can achieve all the anonymities while having small overheads on computation, storage, and communication. We compare our anonymous communication protocol with several existing schemes, and the results show that our protocol provides strong anonymity protection and has low overheads. Copyright © 2011 John Wiley & Sons, Ltd.     

Minimum latency joint scheduling and routing in wireless sensor networks

Wireless sensor networks are expected to be used in a wide range of applications from environment monitoring to event detection. The key challenge is to provide energy efficient communication; however, latency remains an important concern for many applications that require fast response. In this paper, we address the important problem of minimizing average communication latency for the active flows while providing energy-efficiency in wireless sensor networks. As the flows in some wireless sensor network can be long-lived and predictable, it is possible to design schedules for sensor nodes so that nodes can wake up only when it is necessary and asleep during other times. Clearly, the routing layer decision is closely coupled to the wakeup/sleep schedule of the sensor nodes. We formulate a joint scheduling and routing problem with the objective of finding the schedules and routes for current active flows with minimum average latency. By constructing a novel delay graph, the problem can be solved optimally by employing the M node-disjoint paths algorithm under FDMA channel model. We further present extensions of the algorithm to handle dynamic traffic changes and topology changes in wireless sensor networks.     

Performance analysis of wireless sensor networks assisted by on‐demand‐based cloud infrastructure

The wireless sensor networks composed of tiny sensor with the capability of monitoring the tangible changes for a wide range of applications are limited with the capabilities on processing and storage. Their limited capabilities make them seek the help of the cloud that provides the rented service of processing and storage. The dense deployment of the wireless sensor and their vulnerability to the unknown attacks, alterations make them incur difficulties in the process of the conveyance causing the modifications or the loss of the content. So, the paper proposes an optimized localization of the nodes along with the identification of the trusted nodes and minimum distance path to the cloud, allowing the target to have anytime and anywhere access of the content. The performance of the cloud infrastructure‐supported wireless sensor network is analyzed using the network simulator 2 on the terms of the forwarding latency, packet loss rate, route failure, storage, reliability, and the network longevity to ensure the capacities of the cloud infrastructure‐supported wireless sensor networks.     

Optimal power allocating for correlated data fusion in decentralized WSNs using algorithms based on swarm intelligence

Wireless Networks - In unstructured wireless sensor networks (WSNs), which consist of a dense collection of sensor nodes deployed randomly, the communication and processing capabilities of sensor...     

An efficient cluster-based communication protocol for wireless sensor networks

A wireless sensor network is a network of large numbers of sensor nodes, where each sensor node is a tiny device that is equipped with a processing, sensing subsystem and a communication subsystem. The critical issue in wireless sensor networks is how to gather sensed data in an energy-efficient way, so that the network lifetime can be extended. The design of protocols for such wireless sensor networks has to be energy-aware in order to extend the lifetime of the network because it is difficult to recharge sensor node batteries. We propose a protocol to form clusters, select cluster heads, select cluster senders and determine appropriate routings in order to reduce overall energy consumption and enhance the network lifetime. Our clustering protocol is called an Efficient Cluster-Based Communication Protocol (ECOMP) for Wireless Sensor Networks. In ECOMP, each sensor node consumes a small amount of transmitting energy in order to reach the neighbour sensor node in the bidirectional ring, and the cluster heads do not need to receive any sensed data from member nodes. The simulation results show that ECOMP significantly minimises energy consumption of sensor nodes and extends the network lifetime, compared with existing clustering protocol.     

基于发布/订阅模型的WSN设计

为降低通信频率对节点能耗的影响同时提高大规模节点下传感器网络的连通率,本文设计了一种以发布/订阅模型作为应用层数据交互方式的无线传感器网络。该网络利用6LoWPAN技术实现组网,并以Contiki操作系统为平台完成了基于发布/订阅模型的MQTT-S应用层协议设计。测试结果表明,该设计能够有效降低节点的通信流量,实现对节点功耗以及网络通信优化,并能与互联网实现无缝连接减少开发成本,对大规模传感器网络的设计与应用具有重要意义。     

Reinforcement Learning for Multiple Access Control in Wireless Sensor Networks: Review, Model, and Open Issues

Wireless sensor networking is a viable communication technology among low-cost and energy-limited sensor nodes deployed in an environment. Due to high operational features, the application area of this technology is extended significantly but with some energy related challenges. One main cause of the nodes energy wasting in these networks is idle listening characterized with no communication activity. This drawback can be mitigated by the means of energy-efficient multiple access control schemes so as to minimize idle listening. In this paper, we discuss the applicability of distributed learning algorithms namely reinforcement learning towards multiple access control (MAC) in wireless sensor networks. We perform a comparative review of relevant work in the literature and then present a cooperative multi agent reinforcement learning framework for MAC design in wireless sensor networks. Accordingly, the paper concludes with some major challenges and open issues of distributed MAC design using reinforcement learning.     

A new hybrid key pre-distribution scheme for wireless sensor networks

This article presents a novel hybrid key pre-distribution scheme based on combinatorial design keys and pair-wise keys. For the presented scheme, the deployment zone is cleft into equal-sized cells. We use the combinatorial design based keys to secure intra-cell communication, which helps to maintain low key storage overhead in the network. For inter-cell communication, each cell maintain multiple associations with all the other cells within communication range and these associations are secured with pair-wise keys. This helps to ensure high resiliency against compromised sensor nodes in the network. We provide in-depth analysis for the presented scheme. We measure the resiliency of the presented scheme by calculating fraction of links effected and fraction of nodes disconnected when adversary compromises some sensor nodes in the network. We find that the presented scheme has high resiliency than majority of existing schemes. Our presented scheme also has low storage overhead than existing schemes.

     

行星表面有人探索高速无线网络体系架构及关键技术

针对行星表面有人探索任务对高速无线通信的需求，提出了一种基于异构组网思想的网络体系架构，并对关键技术进行了分析和设计。该架构采用“三网两体制”的设计思路，将整个网络分为高速传输网、多媒体接入网、覆盖扩展网三个组成部分，三层网络分别完成高速骨干传输、多节点多业务接入、覆盖范围灵活改变的功能。根据三个网络不同的节点处理能力和传输需要，设计了高速传输体制、灵活接入体制两种传输体制，及基于无线多跳的覆盖扩展技术、多子网通信切换技术、多体制融合技术等关键技术。该网络架构具有裁剪灵活、协议开销小、支持业务类型多等特点。     

无线传感器网络的路由协议研究

微机电系统、处理器、无线通信及存储技术的进步促进了无线传感器网络的飞速发展,使得无线传感器网络成为一种全新的信息获取和处理技术。在对其网络特点进行分析的基础上,介绍了无线传感器网络体系结构。路由技术是无线传感器网络通信层的核心技术,也是其组网的基础,着重讨论了无线传感器网络的路由协议的特点及其相关问题。     

Detection, classification, and tracking of targets

Networks of small, densely distributed wireless sensor nodes are being envisioned and developed for a variety of applications involving monitoring and the physical world in a tetherless fashion. Typically, each individual node can sense in multiple modalities but has limited communication and computation capabilities. Many challenges must be overcome before the concept of sensor networks In particular, there are two critical problems underlying successful operation of sensor networks: (1) efficient methods for exchanging information between the nodes and (2) collaborative signal processing (CSP) between the nodes to gather useful information about the physical world. This article describes the key ideas behind the CSP algorithms for distributed sensor networks being developed at the University of Wisconsin (UW). We also describe the basic ideas on how the CSP algorithms interface with the networking/routing algorithms being developed at Wisconsin (UW-API). We motivate the framework via the problem of detecting and tracking a single maneuvering target. This example illustrates the essential ideas behind the integration between UW-API and UW-CSP algorithms and also highlights the key aspects of detection and localization algorithms. We then build on these ideas to present our approach to tracking multiple targets that necessarily requires classification techniques becomes a reality     

Long range-based low-power wireless sensor node

Sensor nodes are the most significant part of a wireless sensor network that offers a powerful combination of sensing, processing, and communication. One major challenge while designing a sensor node is power consumption, as sensor nodes are generally battery-operated. In this study, we proposed the design of a low-power, long range-based wireless sensor node with flexibility, a compact size, and energy efficiency. Furthermore, we improved power performance by adopting an efficient hardware design and proper component selection. The Nano Power Timer Integrated Circuit is used for power management, as it consumes nanoamps of current, resulting in improved battery life. The proposed design achieves an off-time current of 38.17309 nA, which is tiny compared with the design discussed in the existing literature. Battery life is estimated for spreading factors (SFs), ranging from SF7 to SF12. The achieved battery life is 2.54 years for SF12 and 3.94 years for SF7. We present the analysis of current consumption and battery life. Sensor data, received signal strength indicator, and signal-to-noise ratio are visualized using the ThingSpeak network.     

医疗监护无线传感器网络的研究

无线传感器网络具备传感、计算和无线通信等能力,如何将它应用到传统的医疗监护领域是一个很大的挑战.无线传感器网络的实现难点在于网络体系机构、操作系统、通信协议和应用软件等方面的设计.设计了一种心电医疗监护无线传感器网络,它对于医院病人的心电实时监护和临床医学诊断具有重要的实际意义,详细介绍了无线传感器网络体系结构和系统软硬件设计,尤其在节点硬件和通信协议两方面进行了深入的阐述.     

IBLEACH: intra-balanced LEACH protocol for wireless sensor networks

Wireless sensor networks (WSNs) are composed of many low cost, low power devices with sensing, local processing and wireless communication capabilities. Recent advances in wireless networks have led to many new protocols specifically designed for WSNs where energy awareness is an essential consideration. Most of the attention, however, has been given to the routing protocols since they might differ depending on the application and network architecture. Minimizing energy dissipation and maximizing network lifetime are important issues in the design of routing protocols for WSNs. In this paper, the low-energy adaptive clustering hierarchy (LEACH) routing protocol is considered and improved. We propose a clustering routing protocol named intra-balanced LEACH (IBLEACH), which extends LEACH protocol by balancing the energy consumption in the network. The simulation results show that IBLEACH outperforms LEACH and the existing improvements of LEACH in terms of network lifetime and energy consumption minimization.     

基于无线传感器网络的移动目标跟踪系统研究

脉冲多普勒雷达(PDR)是一个超宽带雷达系统,不仅能探测目标位置,也可通过多普勒效应测量其径向速度。然而,传统的雷达信号处理技术与极限计算和典型无线传感器微粒上的存储资源不相匹配。利用小型脉冲多普勒雷达作为传感器节点,通过设计一个新的目标跟踪系统来探索脉冲多普勒雷达和微型无线传感器节点的兼容性。该系统由几个PDR传感器节点组成,来检测移动目标的存在和位置,一个基站节点用来收集传感器节点的检测数据,一个算法来估计目标的位置。结果表明该系统有较小的偏差,可实现目标跟踪。