无线体域网技术研究

体域网技术是无线传感器网络研究的一个重要应用方向,在远程医疗、健康监护等领域有着广阔的应用前景,该技术的应用对解决看病难看病贵等问题和应对人口老龄化问题方面有着重要的实际意义.对体域网技术进行了详细的阐述,给出了体域网技术的概念和应用领域.然后,并根据现有的研究总结给出了一个面向医护领域的典型的体域网体系结构.从无线通信、介质访问控制、安全等几个体域网重点研究方向,讨论了当前体域网研究的热点.最后,给出总结并作出展望.     

Cloudlet-based Efficient Data Collection in Wireless Body Area Networks

Wireless Body Area Networks (WBANs) have developed as an effective solution for a wide range of healthcare, military and sports applications. Most of the proposed works studied efficient data collection from individual and traditional WBANs. Cloud computing is a new computing model that is continuously evolving and spreading. This paper presents a novel cloudlet-based efficient data collection system in WBANs. The goal is to have a large scale of monitored data of WBANs to be available at the end user or to the service provider in reliable manner. A prototype of WBANs, including Virtual Machine (VM) and Virtualized Cloudlet (VC) has been proposed for simulation characterizing efficient data collection in WBANs. Using the prototype system, we provide a scalable storage and processing infrastructure for large scale WBANs system. This infrastructure will be efficiently able to handle the large size of data generated by the WBANs system, by storing these data and performing analysis operations on it. The proposed model is fully supporting for WBANs system mobility using cost effective communication technologies of WiFi and cellular which are supported by WBANs and VC systems. This is in contrast of many of available mHealth solutions that is limited for high cost communication technology, such as 3G and LTE. Performance of the proposed prototype is evaluated via an extended version of CloudSim simulator. It is shown that the average power consumption and delay of the collected data is tremendously decreased by increasing the number of VMs and VCs.     

无线体域网中节点认证方案研究

针对无线体域网中节点身份认证问题,本文在传统椭圆曲线签名算法的基础上,提出了一种新的在线\离线椭圆曲线签名方案。该方案在未确定签名消息之前进行离线签名,在确定要加密的消息和身份私钥之后进行在线签名。对该方案进行了安全性分析,证明了其具有正确性、不可伪造、不可否认、抵御重放攻击、轻量级的优点,同时通过运算量的对比分析,表明该方案由于取消了求逆运算,具有较大的计算优势。     

雾计算辅助的无线体域网任务卸载方法

基于无线体域网(Wireless Body Area Network,WBAN)的智慧医疗在取得广泛关注的同时也面临诸多挑战,传统方法引入云计算解决体域网网关设备(HUB)资源受限问题,但实时性差.采用低时延的雾计算辅助的方法对体域网生理数据进行处理,提出了一种雾计算目标节点优化选择及任务卸载方法.该方法充分考虑紧急任...     

体域医学传感器网络的设计及其QoS性能分析

提出医学无线传感器网络（MWSNs）的三层体系结构,并重点分析体域医学传感器网络的组成结构和网络传输需求。设计了基于IEEE 802.15.4无线个域网协议的体域医学传感器网络（BA-MWSN）,其拓扑结构采用星型,MAC采用时隙CSMA/CA机制。通过网络仿真评估了该BA-MWSN的QoS性能,分析表明：该网络能满足体域MWSNs的网络传输要求;设置合理的节点数量、网络负载和使用长帧可以获得较高的网络利用率和可靠性。     

Self-Configuration for Wireless Local Area Networks

This paper concentrates on self-configuration in wireless local area networks (WLANs). As the growth of the stringent demand of heterogeneity and re-configurability in future wireless networks, the initial configuration is getting more and more complex, especially in WLANs. In order to minimize the complexity of the configuration of the new deployed AP, this paper focuses on two key issues of self-configuration, network condition awareness and corresponding configuration decision. By designing three neighboring AP discovery mechanisms, network condition could be promptly perceived. And then, with the obtained information of neighboring APs, self-configuration decisions are made based on analytic hierarchy process (AHP) and grey relational analysis (GRA) for mode configuration and channel selection. Benefiting from self-configuration, the complexity and the cost of both configuration and maintenance for WLANs are significantly reduced. A mass of simulations prove that self-configuration works well in increasing the network capacity and reducing the inter-network interference.     

A cooperative approach for topology control in Wireless Sensor Networks

The choice of the transmission power levels adopted in Wireless Sensor Networks (WSNs) is critical to determine the performance of the network itself in terms of energy efficiency, connectivity and spatial reuse, since it has direct impact on the physical network topology.In this paper, a cooperative, lightweight and fully distributed approach is introduced to adaptively tune the transmission power of sensors in order to match local connectivity constraints. To accurately evaluate the topology control solution, a small-scale testbed based on MicaZ sensor nodes is deployed in indoor and outdoor scenarios. Practical measures on local and multi-hop connectivity, convergence time and emitted power are used to compare the proposed approach against previous solutions. Moreover, mathematical programming formulations of the topology (power) control problem are introduced to assess the optimality of the distributed algorithm. Finally, simulation analysis complements the experimental evaluation in large-scale static and mobile WSN scenarios, where a testbed implementation becomes unfeasible.     

iM-SIMPLE: iMproved stable increased-throughput multi-hop link efficient routing protocol for Wireless Body Area Networks

Wireless Body Area Networks (WBANs) are envisaged to play crucial role in psychological, medical and non-medical applications. This paper presents iM-SIMPLE; a reliable, and power efficient routing protocol with high throughput for WBAN. We deploy sensor nodes on human body to measure the physiological parameters such as blood pressure, temperature, glucose, lactic acid, EMG, acceleration, pressure, and position. Data from sensors is forwarded to intermediate node, from where it is transmitted to sink. An end user can access the required information available at sink via internet. To minimize energy consumption of the network, we utilize multi-hop mode of communication. A cost function is introduced to select the forwarder; node with high residual energy and least distance to sink has minimum cost function value and is selected. Residual energy parameter balances the energy consumption among the sensor nodes, and least distance improves packet delivery to sink because of reduced less path loss. We formulate the minimum energy consumption and high throughput problems as an Integer Linear Program. In order to support mobility, we also consider two body postures. Simulation results confirm the performance advantage of iM-SIMPLE compared to contemporary schemes in terms of maximizing stability period and throughput of the network.     

基于WSNs的部分覆盖应用的节点唤醒机制

无线传感网络WSNs(Wireless Sensor Networks)已广泛应用于各类领域.然而,由于能量有限,提高传感节点能效是一项挑战工作.休眠调度策略是保存能量、延长网络寿命的有效策略.此外,多数WSNs应用并不要求100％的覆盖.为此,提出面向部分覆盖应用的节点唤醒机制,且标记为PCLA.PCLA机制引用学习自动机去合理地唤醒节点,而其他节点休眠,进而延长网络寿命.首先,唤醒部分节点构成主干网,然后,再利用这些节点的邻居去满足网络覆盖要求.实验数据表明,与同类机制相比,提出的PCLA机制能够有效地满足部分覆盖要求,并且在活动节点数和网络寿命方面也具有较好的性能.     

BodyCloud: A SaaS approach for community Body Sensor Networks

Body Sensor Networks (BSNs) have been recently introduced for the remote monitoring of human activities in a broad range of application domains, such as health care, emergency management, fitness and behavior surveillance. BSNs can be deployed in a community of people and can generate large amounts of contextual data that require a scalable approach for storage, processing and analysis. Cloud computing can provide a flexible storage and processing infrastructure to perform both online and offline analysis of data streams generated in BSNs. This paper proposes BodyCloud, a SaaS approach for community BSNs that supports the development and deployment of Cloud-assisted BSN applications. BodyCloud is a multi-tier application-level architecture that integrates a Cloud computing platform and BSN data streams middleware. BodyCloud provides programming abstractions that allow the rapid development of community BSN applications. This work describes the general architecture of the proposed approach and presents a case study for the real-time monitoring and analysis of cardiac data streams of many individuals.     

无线局域网吞吐量优化算法

针对无线局域网吞吐量较小且稳定性较差的问题,分析影响无线网络吞吐量性能的因素,提出无线局域网吞吐量优化算法,采用马尔科夫链理论建立吞吐量计算模型,运用动态调整竞争窗口、优化数据帧长度、改进退避时间的策略。NS2仿真结果表明,该算法能有效提高无线局域网的吞吐量。     

Security of Wireless Local Area Networks

The rise of integrated information systems is transforming modern organizations to an extent not envisioned just a few years ago. The dependence of major organizations on these computer supersystems makes it imperative that management provide adequate controls. Many attempts to improve system security are not only inadequate but ill conceived. Our ability to create exceeds our ability to control, and the results can be disastrous. This article discusses the critical role of ID verification in integrated system environments. The inadequacies of memorized passwords as the means of ID verification are discussed, sophisticated ID technologies are described, and the benefits of an integrated approach are enumerated.     

一种面向无线体域网的改进SMART算法

将SMART数据融合算法应用于无线体域网时存在通信量大和精确度低的问题。为此,分别对算法中数据分片、串通和融合阶段进行优化,提出一种改进的SMART算法。在数据分片阶段禁止非叶子节点发送数据并构建不分片节点集,减少通信量;在数据串通阶段利用负数分片数据平衡通信碰撞损失,提高融合精确度;在数据融合阶段对无线体域网重复性数据进行规约处理,进一步减少通信量。性能分析与仿真结果表明,改进算法可在保证原算法隐私保护性不变的前提下,有效提升运算效率和融合精确度。     

适用于无线体域网的动态口令认证协议

无线体域网中传输的是与生命高度相关的敏感数据，身份认证是信息安全保护的第一道防线。现有的基于人体生物信息的身份认证方案存在信息难提取、偶然性大和误差性大的问题，基于传统密码学的认证方案需较大计算资源和能量消耗，并不适用于无线体域网环境。为此，在动态口令和非对称加密机制基础上，提出一种适用于无线体域网的动态口令双向认证轻量协议，并对其进行形式化分析。通过理论证明、SVO逻辑推理及SPIN模型检测得出：该协议满足双向认证，且能够抵御重放攻击、伪装攻击、拒绝服务器攻击和口令离线攻击，具有较高安全性。     

一种基于学习自动机的WSN区域覆盖算法

基于连通支配集(Connected dominating set,CDS)的区域覆盖算法大都采用休眠节点数量的最大化机制来实现节能,这将给无线传感器网络中的活动节点带来沉重的负担。活动节点电能的迅速耗尽将导致CDS失效,产生覆盖盲区。不断激活其他休眠节点,会出现频繁的网络拓扑变化,导致网络收敛性出现问题。提出了一种基于学习自动机的WSN区域覆盖算法。采用受度限制的连通支配集d-CDS来构造WSN骨干网络,利用学习自动机选择当前节点的最优邻居节点,以此实现对所构造CDS的优化,实现活动节点的负载均衡,改善区域覆盖性能。通过仿真实验对比Gossip、ST-MSN和TMPO等算法,表明本文提出的算法在网络覆盖比率、活动节点的剩余电量等方面均存在优势。     

A cluster-based key agreement scheme using keyed hashing for Body Area Networks

In recent years, Body Area Networks (BANs) have gained immense popularity in the domain of healthcare as well as monitoring of soldiers in the battlefield. Security of a BAN is inevitable as we secure the lives of soldiers and patients. In this paper, we propose a security framework using Keyed-Hashing Message Authentication Code (HMAC-MD5) to protect the personal information in a BAN. We assume a network in which nodes sense physiological variables such as electrocardiography (EKG), electroencephalography (EEG), pulse oximeter data, blood pressure and cardiac output. Heterogeneous wireless sensor network is considered which consists of a powerful High-end sensor (H-sensor) and several Low-end sensors (L-sensors). EKG is used for secure communication between nodes as it introduces plug and play capability in BANs. The process is made secure by applying HMAC-MD5 on EKG blocks. Key agreement is done by comparing HMAC of feature blocks between sensors resulting in a more secure network. The analysis is done by calculating the entropy of keys and checking the randomness of EKG data using NIST-randomness testing suite.     

IEEE802.15.6无线体域网CSMA/CA接入机制建模与性能分析

无线体域网是由附着在人体表的可穿戴传感器或植入人体内的生物传感器组成的无线网络.IEEE 802.15工作组于2012年正式发布了用于无线体域网的IEEE 802.15.6通信标准.该标准面向窄带通信主要采用支持QoS区分服务的时隙CSMA/CA接入机制.为深入理解该机制的内在特性,利用Markov链对饱和状态下的退避过程进行建模,并在此基础上分析了各个优先级的吞吐量、成功收包率和延迟等性能.仿真结果验证了模型分析的准确性.分析和仿真结果表明,该标准为不同优先级提供了区分服务,但在饱和状态下最高优先级会抢占大部分信道资源,造成其他优先级的资源短缺.     

为移动体域网供能的射频能量源布置方法

得益于无线能量传输技术的突破,体域网节点可以捕获射频能量源的无线电波能量进行充电,从而持续不间断地工作.对能量源数量和位置进行合理规划可以有效提高节点的能量捕获功率,降低部署成本.现有工作大多考虑节点静止情况下的能量源部署问题或通过概率统计模型转化为节点静止的情况,因此具有明显的局限性.考虑体域网应用背景下,携带可穿戴节点的用户具有特定停留-移动模式,基于该模型归纳了满足节点能量不中断概率要求的能量源优化布置问题,并将该问题的限制条件分解,转化为一个等价问题.分别基于贪婪算法和分治-粒子群算法设计了能量源优化布置算法.通过多组仿真实验,在不同参数下将两种算法与现有路径覆盖算法的性能进行了对比.实现结果表明,在满足节点能量不中断概率要求的前提下,分治-粒子群算法相比贪婪算法和路径覆盖算法更能节省能量源部署成本.     

一种基于反馈调节的无线体域网功率控制算法

无线体域网中节点功率控制需要根据当前链路状况动态调节,信号强度反映的链路状况和固定的函数模型在人体环境变化下能耗较大。针对上述问题,提出一种反馈调节算法,以合理选择功率等级。采用链路质量均值表征链路状况,用比例、积分、微分算法进行反馈控制。实验结果表明,与传统乘增加减算法和动态姿势推测算法相比,在保证97.6%包接收率的前提下,该算法的节点平均能耗分别减少17.3 m W和13.7 m W,网络生存期平均提高28.7%和23.4%。     

基于K-means的无线家域网分簇算法

针对无线家域网的应用特点,提出一种基于K-means的无线家域网分簇算法。以LEACH协议中的最优分簇个数作为K-means聚类的输入参数,在家域网基站上实现集中式按需分簇,并利用Silhouette值判定最优的分簇及簇头。实验结果表明,在无线家域网仿真场景中,该算法能获得较好的分簇聚类效果。