Directed diffusion for wireless sensor networking

Advances in processor, memory, and radio technology enable small and cheap nodes capable of sensing, communication, and computation. Networks of such nodes can coordinate to perform distributed sensing of environmental phenomena. We explore the directed diffusion paradigm for such coordination. Directed diffusion is data-centric in that all communication is for named data. All nodes in a directed-diffusion-based network are application aware. This enables diffusion to achieve energy savings by selecting empirically good paths and by caching and processing data in-network (e.g., data aggregation). We explore and evaluate the use of directed diffusion for a simple remote-surveillance sensor network analytically and experimentally. Our evaluation indicates that directed diffusion can achieve significant energy savings and can outperform idealized traditional schemes (e.g., omniscient multicast) under the investigated scenarios.     

Exploiting classification for fountain data estimation in wireless sensor networks

In order to correct and avoid channel error, fountain codes were the best solution by limiting feedback channels and reducing energy consumption. Multi‐hops transmission is the principal limitation of the deployment and the use of these codes. Indeed, relayed transmission conducts to the generation of useless data, named overflow leading to a waste of energy, the most critical issue, and the big challenge in WSN. In this paper, based on a clustered architecture and estimation, we consider a distributed estimation scheme composing of sensor members and the cluster head. In order to reduce the number of a useless encoded packet generated as well as the impact of the overflow, we determine the optimal minimal number of encoded packets needed for data decoding. Sensor observations are encoded using fountain codes, and then messages are collected at the cluster head where a final estimation is provided within learning method. Then messages are collected at the cluster head where a final estimation is provided with a classification based on Bayes rule. The main goal of this paper is to determine the number of encoded packets by exploiting the classification model for fountain data estimation to minimize the overflow and extend the network lifetime.     

无线传感器网络中具有撤销功能的自愈组密钥管理方案

在有限域F_q上构造基于秘密共享的广播多项式,提出一种具有节点撤销功能的组密钥更新方案.同时,基于单向散列密钥链建立组密钥序列,采用组密钥预先更新机制,容忍密钥更新消息的丢失,实现自愈.分析表明,在节点俘获攻击高发的环境中,方案在计算开销和通信开销方面具有更好的性能.     

Exploiting cognitive wireless nodes for priority‐based data communication in terrestrial sensor networks

A priority‐based data communication approach, developed by employing cognitive radio capacity for sensor nodes in a wireless terrestrial sensor network (TSN), has been proposed. Data sensed by a sensor node—an unlicensed user—were prioritized, taking sensed data importance into account. For data of equal priority, a first come first serve algorithm was used. Non‐preemptive priority scheduling was adopted, in order not to interrupt any ongoing transmissions. Licensed users used a nonpersistent, slotted, carrier sense multiple access (CSMA) technique, while unlicensed sensor nodes used a nonpersistent CSMA technique for lossless data transmission, in an energy‐restricted, TSN environment. Depending on the analytical model, the proposed wireless TSN environment was simulated using Riverbed software, and to analyze sensor network performance, delay, energy, and throughput parameters were examined. Evaluating the proposed approach showed that the average delay for sensed, high priority data was significantly reduced, indicating that maximum throughput had been achieved using wireless sensor nodes with cognitive radio capacity.     

Overview of networking protocols for underwater wireless communications

Underwater wireless communications can enable many scientific, environmental, commercial, safety, and military applications. Wireless signal transmission is also crucial to remotely control instruments in ocean observatories and to enable coordination of swarms of autonomous underwater vehicles and robots, which will play the role of mobile nodes in future ocean observation networks by virtue of their flexibility and reconfigurability. To make underwater applications viable, efficient communication protocols among underwater devices, which are based on acoustic wireless technology for distances over one hundred meters, must be enabled because of the high attenuation and scattering that affect radio and optical waves, respectively. The unique characteristics of an underwater acoustic channel -- such as very limited and distance-dependent bandwidth, high propagation delays, and timevarying multipath and fading -- require new, efficient and reliable communication protocols to network multiple devices, either static or mobile, potentially over multiple hops. In this article, we provide an overview of recent medium access control, routing, transport, and crosslayer networking protocols.     

The wireless segment of enterprise networking

Changes in the business environment are transforming people's mode of operation and work habits. Many corporate employees spend time away from their assigned wired phones but are still in their offices or other locations of the company. Companies are starting to be aware of the opportunities that mobility offers to increase productivity, provide better customer service, and lead to future cost savings. Thus, companies are increasingly adding mobility solutions to their existing networks and continuously integrate them as seamlessly as possible. The emerging answer is enterprise wireless telephony, which, unlike its public cellular counterpart, is free of air time charges. This article describes the enterprise wireless technologies. We briefly introduce the location system and then focus on communications services with solutions for single- and multilocation enterprise     

Evaluation method for autonomous communication and networking capability of UAV

In order to accurately evaluate the autonomous communication and networking capability of these unmanned system which was instructive to the intelligent collaboration of UAV (unmanned aerial vehicle) system,the research of the UAV system which was adapted to the complex environment with countermeasure possibilities was focused on.The autonomous communication and networking capability of UAV system and their relationship from multiple perspectives was analyzed and modeled,including self-adaptation,self-decision,man-UAV interaction,cyber-physical integration and evolution,and an example was provided to illustrate the detailed evaluation process.The example results show that the proposed method comprehensively consider all the key aspects of the performance evaluation,which can be used to quantitatively evaluate the autonomous communication and networking capability of different UAVs or other unmanned systems.     

An integrated security framework for open wireless networking architecture

An integrated security mechanism is one of the key challenges in the open wireless network architecture because of the diversity of the wireless networks in OWA and the unique security mechanism used in each one of these networks. Because the overall security of the network is as strong as its weakest component, integration of the overall security mechanism in OWA is of primary importance. In this article, we comparatively analyze the unique network-centric features and security mechanisms of various heterogeneous wireless networks that are expected to be part of OWA. Then, after defining the specific integrated network model of OWA, we propose an integrated security platform based on the security profile concept     

Adaptive link layer strategies for energy efficient wireless networking

Low power consumption is a key design metric for portable wireless network devices where battery energy is a limited resource. The resultant energy efficient design problem can be addressed at various levels of system design, and indeed much research has been done for hardware power optimization and power management within a wireless device. However, with the increasing trend towards thin client type wireless devices that rely more and more on network based services, a high fraction of power consumption is being accounted for by the transport of packet data over wireless links [28]. This offers an opportunity to optimize for low power in higher layer network protocols responsible for data communication among multiple wireless devices. Consider the data link protocols that transport bits across the wireless link. While traditionally designed around the conventional metrics of throughput and latency, a proper design offers many opportunities for optimizing the metric most relevant to battery operated devices: the amount of battery energy consumed per useful user level bit transmitted across the wireless link. This includes energy spent in the physical radio transmission process, as well as in computation such as signal processing and error coding. This paper describes how energy efficiency in the wireless data link can be enhanced via adaptive frame length control in concert with adaptive error control based on hybrid FEC (forward error correction) and ARQ (automatic repeat request). Key to this approach is a high degree of adaptivity. The length and error coding of the atomic data unit (frame) going over the air, and the retransmission protocol are (a) selected for each application stream (ATM virtual circuit or IP/RSVP flow) based on quality of service (QoS) requirements, and (b) continually adapted as a function of varying radio channel conditions due to fading and other impairments. We present analysis and simulation results on the battery energy efficiency achieved for user traffic of different QoS requirements, and describe hardware and software implementations.     

Energy‐efficient wireless networking for multimedia applications

In this paper we identify the most prominent problems of wireless multimedia networking and present several state‐of‐the‐art solutions with a focus on energy efficiency. Three key problems in networked wireless multimedia systems are: (1) the need to maintain a minimum quality of service over time‐varying channels; (2) to operate with limited energy resources; and (3) to operate in a heterogeneous environment. We identify two main principles to solve these problems. The first principle is that energy efficiency should involve all layers of the system. Second, Quality of Service is an essential mechanism for mobile multimedia systems not only to give users an adequate level of service, but also as a tool to achieve an energy‐efficient system. Owing to the dynamic wireless environment, adaptability of the system will be a key issue in achieving this. Copyright © 2001 John Wiley & Sons, Ltd.     

High-rise structure monitoring with elevator-assisted wireless sensor networking: design,optimization, and case study

Wireless Networks - Wireless sensor networks have been widely suggested to be used in cyber-physical systems for structural health monitoring. However, for nowadays high-rise structures (e.g., the...     

BSLPSDN: Base station location privacy via software-defined networking (SDN) in wireless sensor networks

Base station's location privacy in a wireless sensor network (WSN) is critical for information security and operational availability of the network. A key part of securing the base station from potential compromise is to secure the information about its physical location. This paper proposes a technique called base station location privacy via software-defined networking (SDN) in wireless sensor networks (BSLPSDN). The inspiration comes from the architecture of SDN, where the control plane is separated from the data plane, and where control plane decides the policy for the data plane. BSLPSDN uses three categories of nodes, namely, a main controller to instruct the overall operations, a dedicated node to buffer and forward data, and lastly, a common node to sense and forward the packet. We employ three kinds of nodes to collaborate and achieve stealth for the base station and thus protecting it against the traffic-analysis attacks. Different traits of the WSN including energy status and traffic density can actively be monitored by BSLPSDN, which positively affects the energy goals, expected life of the network, load on common nodes, and the possibility of creating diversion in the wake of an attack on the base station. We incorporated multiple experiments to analyze and evaluate the performance of our proposed algorithm. We use single controller with multiple sensor nodes and multiple controllers with multiple sensor nodes to show the level of anonymity of BS. Experiments show that providing BS anonymity via multiple controllers is the best method both in terms of energy and privacy.     

Localization systems for wireless sensor networks

Monitoring applications define an important class of applications used in wireless sensor networks. In these applications the network perceives the environment and searches for event occurrences (phenomena) by sensing different physical properties, such as temperature, humidity, pressure, ambient light, movement, and presence (for target tracking). In such cases the location information of both phenomena and nodes is usually required for tracking and correlation purposes. In this work we summarize most of the concepts related to localization systems for WSNs as well as how to localize the nodes in these networks (which allows the localization of phenomena). By dividing the localization systems into three distinct components -distance/angle estimation, position computation, and localization algorithm - besides providing a didactic viewpoint, we show that these components can be seen as subareas of the localization problem that need to be analyzed and studied separately.     

Energy-efficient DSPs for wireless sensor networks

There are many new challenges to be faced in implementing signal processing algorithms and designing energy-efficient DSPs for microsensor networks. We study system partitioning of computation to improve the energy efficiency of a wireless sensor networking application. We explore system partitioning between the sensor cluster and the base station, employing computation-communication tradeoffs to reduce energy dissipation. Also we show that system partitioning of computation within the cluster can also improve the energy efficiency by using dynamic voltage scaling (DVS)     

无线数字家庭组网技术研究

系统介绍了无线数字家庭组网技术的研究现状和关键技术．对无线数字家庭组网的物理层和媒体接入控制层的相关技术进行了研究．给出了不同关键技术的主要解决方案并且探讨了无线个域网（WPAN）和其他网络共存时的异构组网技术等。     

HomeMesh: a low-cost indoor wireless mesh for home networking

Wi-Fi access technology has become popular in recent years. Many users nowadays use Wi-Fi to gain wireless access to the Internet from offices, public libraries, shopping malls, homes, and other places. However, current Wi-Fi deployment is limited to areas where wired LAN is available. Due to its relatively short transmission range in indoor environments (typically several tens of meters), Wi-Fi coverage needs to be extended significantly to full coverage of a certain area. The wireless mesh network (WMN) is a practical and effective solution. In this article we present HomeMesh, an off-the-shelf, simple, and cost-effective WMN for the indoor home environment. HomeMesh is based on simple protocols, implementable in normal notebooks or PCs, and is compatible with existing Wi-Fi APs and clients (i.e., no AP and client modifications). To achieve better end-to-end delay and throughput, HomeMesh dynamically selects its access path based on the ETX metric. We have implemented HomeMesh and conducted proofof- concept experiments in an indoor environment. Our mesh solution is shown to be effective in improving Wi-Fi services.     

Information coverage for wireless sensor networks

Coverage is a very important issue in wireless sensor networks. Current literature defines a point to be covered if it is within the sensing radius of at least one sensor. In this paper we argue that this is a conservative definition of coverage. This definition implicitly assumes that each sensor makes a decision independent of other sensors in the field. However, sensors can cooperate to make an accurate estimation, even if any single sensor is unable to do so. We then propose a new notion of information coverage and investigate its implications for sensor deployment. Numerical and simulation results show that significant savings in terms of sensor density for complete coverage can be achieved by using our definition of information coverage compared to that by using the existing definition.