基于室内无线传感器网络射频信号的老年人跌倒检测研究

利用无线信号的自然衰减,在不显著增加通信开销的基础上,提出了一种新的老年人跌倒行为的检测方法.给出阶段相关性这一概念并用以区分体域传感器网络节点与室内传感器网络节点信号在人运动与静止条件下的统计相关性.给出了最小通信决策集合的概念,通过对比最小通信决策集合的内容,提出了老年人位置估计方法和跌倒行为检测算法;利用仿真工具...     

Future Applications of Bluetooth

Bluetooth is a short-range radio technology that is increasingly being provided in the various electronic devices that we carry around, such as laptops, mobile telephones and cameras. Bluetooth's supporters claim that it can deliver 'unprecedented productivity' through the seamless interconnection of these devices into a personal area network (PAN) — but does the technology really live up to this expectation? This paper investigates the claims surrounding Bluetooth, and compares its capabilities and potential applications with the existing technologies of DECT and wireless LAN. Bluetooth usage scenarios are considered in the areas of ad hoc networks, the home, the office environment, mCommerce and public access wireless hot-spots. Widespread implementation in devices does not mean widespread usage, and barriers to easy operation are examined to see if Bluetooth can move beyond its personal area network role into new areas of networking that could benefit a broad range of users.     

BorderSense: Border patrol through advanced wireless sensor networks

The conventional border patrol systems suffer from intensive human involvement. Recently, unmanned border patrol systems employ high-tech devices, such as unmanned aerial vehicles, unattended ground sensors, and surveillance towers equipped with camera sensors. However, any single technique encounters inextricable problems, such as high false alarm rate and line-of-sight-constraints. There lacks a coherent system that coordinates various technologies to improve the system accuracy. In this paper, the concept of BorderSense, a hybrid wireless sensor network architecture for border patrol systems, is introduced. BorderSense utilizes the most advanced sensor network technologies, including the wireless multimedia sensor networks and the wireless underground sensor networks. The framework to deploy and operate BorderSense is developed. Based on the framework, research challenges and open research issues are discussed.     

Energy-aware on-demand scatternet formation and routing for Bluetooth-based wireless sensor networks

Bluetooth is a promising short-range wireless communication technology with the characteristics of interference resilience and power efficiency, both desirable for wireless sensor networks. The new Intel Mote sensor devices have Bluetooth technology incorporated as the standard wireless communications interface. When using Bluetooth in applications where multihop routing is required, groups of Bluetooth piconets combine together to form a scatternet. However, most of the existing scatternet formation protocols are designed to facilitate communications between any two pairs of devices, regardless of the actual traffic demand pattern. For wireless sensor network applications with low-duty-cycle traffic patterns, an on-demand scatternet formation protocol can achieve significant power saving by avoiding unnecessary network connectivity. To that end, we introduce an on-demand scatternet and route formation protocol designed specifically for Bluetooth-based wireless sensor networks. Our protocol builds a scatternet on demand, and is able to cope with multiple sources initiating traffic simultaneously. In addition, our energy-aware forwarding nodes selection scheme is based on local information only, and results in more uniform network resource utilization and improved network lifetime. Simulation results show that our protocol can provide scatternet formation with reasonable delay and good load balance, which results in prolonged network lifetime for Bluetooth-based wireless sensor networks.     

A wearable point-of-care system for home use that incorporates plug-and-play and wireless standards.

A point-of-care system for continuous health monitoring should be wearable, easy to use, and affordable to promote patient independence and facilitate acceptance of new home healthcare technology. Reconfigurability, interoperability, and scalability are important. Standardization supports these requirements, and encourages an open market where lower product prices result from vendor competition. This paper first discusses candidate standards for wireless communication, plug-and-play device interoperability, and medical information exchange in point-of-care systems. It then addresses the design and implementation of a wearable, plug-and-play system for home care which adopts the IEEE 1073 Medical Information Bus (MIB) standards, and uses Bluetooth as the wireless communication protocol. This standards-based system maximizes user mobility by incorporating a three-level architecture populated by base stations, wearable data loggers, and wearable sensors. Design issues include the implementation of the MIB standards on microcontroller-driven embedded devices, low power consumption, wireless data exchange, and data storage and transmission in a reconfigurable body-area network.     

Interoperability criteria, mechanisms, and evaluation of system performance for transparently interoperating WLAN and UMTS-HSDPA networks

The main challenge in the development of future wireless communication systems is to provide users with a wide range of services across different radio access technologies through a single mobile terminal, while maintaining the minimum QoS requirements, and ideally with no limits on the coverage area, mobility or radio conditions. Thus, the need for seamless interworking between heterogeneous wireless communication systems consisting of multiple radio access technologies and overlapping networks emerges. In this article we address the main issues that arise while implementing the interoperability mechanisms between two different radio access networks, with emphasis on UMTS-HSDPA and WLAN (HIPERLAN/2). Two interoperability mechanisms are introduced and described in detail: initial user assignment (optimal network selection) and intersystem handover. Both mechanisms are activated via the optimization of a suitably defined cost function which takes into account all the appropriate system level parameters that trigger the interoperability process. Finally, we investigate the overall performance of the proposed mechanisms by means of a software simulation platform. A number of simulations have been carried out in order to demonstrate the performance enhancements achieved by the proposed mechanisms in terms of unsatisfied users, dropped handovers, and system throughput.     

Pervasive, secure access to a hierarchical sensor-based healthcare monitoring architecture in wireless heterogeneous networks

This study presents a healthcare monitoring architecture coupled with wearable sensor systems and an environmental sensor network for monitoring elderly or chronic patients in their residence. The wearable sensor system, built into a fabric belt, consists of various medical sensors that collect a timely set of physiological health indicators transmitted via low energy wireless communication to mobile computing devices. Three application scenarios are implemented using the proposed network architecture. The group-based data collection and data transmission using the ad hoc mode promote outpatient healthcare services for only one medical staff member assigned to a set of patients. Adaptive security issues for data transmission are performed based on different wireless capabilities. This study also presents a monitoring application prototype for capturing sensor data from wireless sensor nodes. The implemented schemes were verified as performing efficiently and rapidly in the proposed network architecture.     

A Bluetooth Based Sensor Network for Civil Infrastructure Health Monitoring

Communicating with sensors has long been limited either to wired connections or to proprietary wireless communication protocols. Using a ubiquitous and inexpensive wireless communication technology to create Sensor Area Networks (SANs) will accelerate the extensive deployment of sensor technology. Bluetooth, an emerging, worldwide standard for inexpensive, local wireless communication is a viable choice for SANs because of its inherent support for some of the important requirements – low power, small form factor, low cost and sufficient communication range. In this paper we outline an approach, centered on the Bluetooth technology, to support a sensor network composed of fixed wireless sensors for health monitoring of highways, bridges and other civil infrastructures. We present a topology formation scheme that not only takes into account the traffic generated by different sensors but also the associated link strengths, buffer capacities and energy availability. The algorithm makes no particular assumptions as to the placement of nodes, and not all nodes need to be in radio proximity of each other. The output is a tree shaped scatternet rooted at the sensor hub (data logger) that is balanced in terms of traffic carried on each of the links. We also analyze the scheduling, routing and healing aspects of the resulting sensor-net topology.     

Design and evaluation of a telemonitoring concept based on NFC-enabled mobile phones and sensor devices

Utilization of information and communication technologies such as mobile phones and wireless sensor networks becomes more and more common in the field of telemonitoring for chronic diseases. Providing elderly people with a mobile-phone-based patient terminal requires a barrier-free design of the overall user interface including the setup of wireless communication links to sensor devices. To easily manage the connection between a mobile phone and wireless sensor devices, a concept based on the combination of Bluetooth and near-field communication technology has been developed. It allows us initiating communication between two devices just by bringing them close together for a few seconds without manually configuring the communication link. This concept has been piloted with a sensor device and evaluated in terms of usability and feasibility. Results indicate that this solution has the potential to simplify the handling of wireless sensor networks for people with limited technical skills.     

Bluetooth-Based Sensor Networks for Remotely Monitoring the Physiological Signals of a Patient

Integrating intelligent medical microsensors into a wireless communication network makes it possible to remotely collect physiological signals of a patient, release the patient from being tethered to monitoring medical instrumentations, and facilitate the patient's early hospital discharge. This can further improve life quality by providing continuous observation without the need of disrupting the patient's normal life, thus reducing the risk of infection significantly, and decreasing the cost of the hospital and the patient. This paper discusses the implementation issues, and describes the overall system architecture of our developed Bluetooth sensor network for patient monitoring and the corresponding heart activity sensors. It also presents our approach to developing the intelligent physiological sensor nodes involving integration of Bluetooth radio technology, hardware and software organization, and our solutions for onboard signal processing.      

Radio access selection for multistandard terminals

The race for higher data rates in wireless systems has produced a multiplicity of radio access methods to fulfill the quality of service needs for the next generation of mobile devices. This document presents an analysis of GERAN, UTRAN, WLAN, and Bluetooth as possible methods of accessing services via a wireless device. In light of the results, meaningful combinations for radio access methods of wireless devices are elaborated     

Actor-oriented directional anycast routing in wireless sensor and actor networks with smart antennas

Current routing protocols in wireless sensor and actor networks (WSANs) shows a lack of unification for different traffic patterns because the communication for sensor to actor and that for actor to actor are designed separately. Such a design poses a challenge for interoperability between sensors and actors. With the presence of rich-resource actor nodes, we argue that to improve network lifetime, the problem transforms from reducing overall network energy consumption to reducing energy consumption of constrained sensor nodes. To reduce energy consumption of sensor nodes, especially in challenging environments with coverage holes/obstacles, we propose that actor nodes should share forwarding tasks with sensor nodes. To enable such a feature, efficient interoperability between sensors and actors is required, and thus a unified routing protocol for both sensors and actors is needed. This paper explores capabilities of directional transmission with smart antennas and rich-resource actors to design a novel unified actor-oriented directional anycast routing protocol (ADA) which supports arbitrary traffic in WSANs. The proposed routing protocol exploits actors as main routing anchors as much as possible because they have better energy and computing power compared to constraint sensor nodes. In addition, a directional anycast routing approach is also proposed to further reduce total delay and energy consumption of overall network. Through extensive experiments, we show that ADA outperforms state-of-the-art protocols in terms of packet delivery latency, network lifetime, and packet reliability. In addition, by offer fault tolerant features, ADA also performs well in challenging environments where coverage holes and obstacles are of concerns.     

Bluetooth's slow dawn

Bluetooth was developed initially by Ericsson as a short-range cable replacement for linking portable consumer electronic products, but it can also be adapted for printers, fax machines, keyboards, toys, games, and virtually any other digital consumer application. The technology provides a mechanism for forming small wireless networks of Bluetooth-equipped products on an ad hoc basis. It can also serve as a wireless bridge to existing data networks. However, hype has given way to hard work as expectations for the mini radio network encounter nettlesome interoperability issues     

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。     

无线传感器网络技术

无线传感器网络是新兴网络,它采用无线通信技术,由微小的传感器组成,无线传感器网络节点具备感应能力、信息处理能力和无线通信能力,使无线传感器网络有广阔的应用前景,可广泛用于军事、环境、医疗保健、空间探索及各种商业应用。无线传感器网络是新的研究领域,文中分析了无线传感器网络研究中的热点问题,讨论了无线传感器网络的应用,展望了无线传感器网络的美好前景。     

Wireless technologies for telemedicine

Wireless telemedicine is a new and evolving area in telemedical and telecare systems. Healthcare personnel require realtime access to accurate patient data, including clinical histories, treatments, medication, tests, laboratory results and insurance information. With large-scale wireless networks and mobile computing solutions, such as cellular 3G, Wi-Fi mesh and WiMAX, healthcare personnal can tap into vital information anywhere and at any time within the healthcare networks. The recent introduction of pervasive computing, consisting of radio frequency identification (RFID), Bluetooth, ZigBee, and wireless sensor networks, further extends the potential for exploitation of wireless telecommunications and its integration into new mobile healthcare delivery systems. In this paper, snapshots of current uses and future trends of various wireless communications in the healthcare domain are highlighted. Special attention is given to the challenges of a telemedicine environment equipped with different wireless technologies and how the resulting issues might be addressed in medical services integration to provide flexible, convenient and economical medical monitoring, consultation and healthcare.     

Taxonomy and Challenges of the Integration of RFID and Wireless Sensor Networks

Radio frequency identification and wireless sensor networks are two important wireless technologies that have a wide variety of applications in current and future systems. RFID facilitates detection and identification of objects that are not easily detectable or distinguishable by using conventional sensor technologies. However, it does not provide information about the condition of the objects it detects. WSN, on the other hand, not only provides information about the condition of the objects and environment but also enables multihop wireless communications. Hence, the integration of these technologies expands their overall functionality and capacity. This article investigates recent research work and applications that integrate RFID with sensor networks. Four classes of integration are discussed: integrating tags with sensors, integrating tags with WSN nodes and wireless devices, integrating readers with WSN nodes and wireless devices, and a mix of RFID and WSNs. Finally, a discussion of new challenges and future work is presented.     

Personal Area Networks: Bluetooth or IEEE 802.11?

Interconnecting all our electronic devices we carry around, such as cellular phones, PDAs, and laptops, with wireless links requires a cheap, low-power radio technology that still delivers good performance. In this context, the Bluetooth wireless technology was developed to meet the requirements introduced by these personal area networks (PANs). However, today we see a widespread deployment of wireless local area network (WLAN) radios (primarily IEEE 802.11b) also in small devices, such as PDAs. This paper will compare the PAN capabilities of a Bluetooth-based system with an IEEE 802.11b-based system. In order to focus the comparison on link and networking functionality, the IEEE 802.11b radio is assumed to be operating at the same power level as the Bluetooth radio (i.e., assuming a 0 dBm radio). Results are obtained by means of simulations in which throughput and delay are measured for multihop and overlaid PANs. Estimations on power usage are also given in the simulations. The results indicate that as the number of PANs increases, the Bluetooth-based PANs basically maintain the same bandwidth per PAN, while the corresponding IEEE 802.11-based PANs suffer significantly from the increased co-channel interference. However, for cases with a few co-channel-interfering PANs (2-3 PANs hosting about 10-15 nodes), the IEEE 802.11b-based PANs offer a higher bandwidth per user than the corresponding Bluetooth PANs, which corresponds to the difference in link bandwidth between the two systems. At high interference levels, the Bluetooth PAN offers a higher capacity than the IEEE 802.11 PAN. The latter also shows unfairness among TCP connections in the PAN at high loads. The energy efficiency, defined as successfully transmitted bits per energy unit, decreases sharply for IEEE 802.11 with increased number of PANs, while Bluetooth maintains a constant level. Packet delays are also shown to be more stable for the Bluetooth PAN than for the IEEE 802.11 PAN as the number of PANs increases.     

Two thermocouples low power wireless sensors network

This paper presents technologies and experiments of a wireless sensors using two thermocouples network. It was established that the energy consumption during sensor measurements is usually up to 10 times lower compared to the energy consumption at the time of establishing wireless connection for most protocols. For this reason, new simplified wireless connection protocol was created.Extremely low energy wireless sensor hardware and software equipment was designed. The newly created universal measurement module allows the use not only thermocouples, but also various types of analogue sensors, thermocouples, pressure bridges, Resistance Temperature Detectors (RTD) and digital sensors communicating through SPI or I2C interface. The newly designed specific power supply scheme allows to supply the sensor and radio module with the voltage from 1.2 V to 3.6 V batteries. When conducting periodic measurements every second, the use of newly designed hardware and software equipment enables the wireless sensor to be operated for up to 3 years from two 1200 mAh capacity batteries.     

Next Generation Wireless Infrastructure

Given the commercial success of wireless technologies that has already taken place over the last couple of decades, with a global mobile communication penetration beyond 3 billion subscribers as well as the enormous success of wireless data communication through IEEE 802.11x and Bluetooth, people could think the wireless revolution is over. However, future connectivity will be wireless and ubiquitous. Therefore the future of wireless infrastructures seems to be in front of a remarkable evolution as this paper will describe. With a vision of creating continuous seamless user connectivity as well as having physical devices/things connected through the wide spread usage of sensor and RFID near field communication technologies the network will increase in size with a order of magnitude compared to today. Additionally having the widespread Internet protocol technologies as a fundamental building block the wireless vision is additionally to create a future wireless ICT environment that can help reduce energy consumption, handle local and global disasters etc. By offering this it is envisioned that wireless ICT can create a base for tackling some of the worlds largest problems using wireless ICT. This paper describes a focused number of research issues to solve in order for this to happen. Completely new disruptive ways of building the architecture is necessary. New ways of thinking where the next level of network intelligence is fundamental, where much more network and device cooperation should be used. New efficient ways of optimizing the spectrum usage are necessary. The extent of IP-based sensor networks with explode due to the rapid evolution in the relationship between processing power, cost, power consumption and physical size.