Performance Analysis of WLAN and Ad hoc Network in the Interference Environment and Study of Related Strategy

现代无线通信要求业务多、移动性强、传输速率高、覆盖范围广，下一代移动通信系统将综合WLAN、WPAN及MANET等各种不同类型的无线网络，在全IP的核心网上高速实现声音、多媒体和数据等多种业务。WLAN和自组织网具有广泛的应用前景。但有限的频率带宽会导致系统间或者系统内的相互干扰，降低网络性能。本论文以WLAN和自组织网为对象，对其性能进行分析，并探讨了减轻干扰的策略。首先讨论了ISM频段无线设备的干扰机理,分析了WLAN在外部干扰下的性能。在蓝牙干扰存在的情况下，用物理层基带模型对WLAN的误码率性能进行了仿真；结合时间-频率冲突分析，对干扰环境下影响WLAN性能的各种因素进行了比较，提出了...Modern communication requires high transmit rate, high mobility, wide converge and multiple services. The next generation mobile communication will integrate various types of wireless network technique such as WLAN, WPAN and MANET, and realize different traffic such as voice, multimedia and data on all-IP core network. WLAN and Ad hoc networks are widely applied in different fields,but the limi...学位：工学博士院系专业：海洋与环境学院环境科学研究中心_环境科学学号：B20023400

AFH Technology of Bluetooth

自适应跳频是蓝牙技术中采用的预防频率冲突的机制 ,他能有效地防止频率碰撞 ,从而保证系统正常的吞吐量The Bluetooth noncollaborative coexistence mechanisms is introduced in this paper.The adaptive frequency hopping (AFH) can avoids the packet collision and gives best system aggregate throughput

Anchor-free Distributed Self-localization Method in Wireless Sensor Network with Range Errors

无线传感器网络中,采用RSSI方法进行自定位时,测距误差会影响定位精度。提出了一种分布式的无锚点定位方法,在对测距误差进行正确估计的基础上,求得各节点的相对位置。首先将测距误差定义为一个目标函数,使用最速下降法来分布式地求解全局非线性优化问题,以使这个目标函数最小化,然后利用节点间的估计距离与实际测量距离的偏差值来修正节点的估计坐标。仿真实验对各种影响参数进行了评估,结果证明:在无锚节点且距离测量值存在误差的情况下,满足一定的节点连通度时,能够提高节点定位精度。In wireless sensor networks,the existing range errors will affect the position accuracy when using RSSI method to locate the nodes' position. Based on the correct estimation of range errors,a distributed location method is proposed,to found the node's position. By using the steepest descent method,an object function of range errors is defined to solve the global nonlinear optimization problem and hence minimize this object function. Due to the estimated distance between the nodes and the deviation value of the actual measurement distance one can update the estimated coordinates of the node. With the existence of range errors and certain requirement of connetivity of nodes,the result shows that the nodes position will be distributed estimated correctly.福建省自然科学基金(2015J01267);; 福建省教育厅科研项目(JA15650,JA15257);; 厦门市科技局项目(2014S0884,3502Z20153010

Modified Power Control Approach Based on CSMA/CA of Wireless Ad hoc Network

基于CSMA/CA机制,提出了一个改进的功率控制算法,用于解决传统的bASIC方案中,由于功率控制的引入而产生的非对称链路对节点传输的碰撞问题,它通过简单地修改802.11MAC层协议,采用变长的rTS/CTS来使载波侦听环中的节点获得关于dATA/ACk传输的分组大小及功率强度信息,从而有效地避免碰撞与重传。仿真结果说明,该方法不仅可以节省能量,而且可以提高网络性能。Based on CSMA/CA scheme,an improved power control algorithm was proposed to solve the Asymmetric Link Problem introduced by power control of BASIC in Ad Hoc networks,which modified 802.11 MAC protocol by using variable size of RTS/CTS to gain the information of data size and power level in the area of carrier sense ring to avoid more collisions and retransmissions.Simulation result shows that the approach can not only save network energy,but also improve network performance.福建省青年创新基金资助项目(2006F3097);福建省自然科学基金资助项目(A0710022);集美大学优秀青年骨干教师基金资助项目(2008B002

Design of cross-layer security for wireless sensor network's

无线传感器网络(WSNs)发展迅速,可广泛应用于军事、工业及科学等领域。传感器网络在无线信道中工作,其节点有限的能源、计算能力、存储能力使得其面临着严重的安全问题。已提出的许多安全方法都基于分层设计的概念。分析了分层安全设计的局限性,回顾了现存的W SNs的安全设计方案,提出了一些新的跨层解决办法,并指出了传感器网络中跨层安全的研究方向。Wireless sensor networks(WSNs) are developing rapidly,it will be employed in a wide variety of applications ranging from military,industrial and social.Due to their constraints in computation,memory,and power resources,security is a challenge in these networks.Many security methods of WSNs based on the concept of layered-design have the limit,the state of art security design method of WSNs is overviewed,several new cross-layer solve methods are proposed,and the research direction of cross-layer design for the security of WSNs is point out.福建省自然科学基金资助项目(A00440004

Modified energy-saving hierarchical data aggregation mechanism for wireless sensor network

考虑WSn中节点的能耗分布情况,提出了一种改进的多级汇聚协议。首先建立分析模型评估了在WSn中采用多级汇聚机制时的能耗情况,证明在SInk附近的汇聚节点的能量增加很快,从而会耗尽能量,缩短整个网络的生存期。然后提出了一个改进的多级汇聚协议,通过改变通过减少离SInk附近的汇聚节点选择概率,可以均衡网络性能。仿真结果证明,该方法可以有效地降低能量,从而延长网络生存期。Considering the distributions of node’s energy consumptions in Wireless Sensor Networks(WSN),a modified hierarchical data aggregation protocol is proposed.Firstly,this paper sets up a simple model to analytically evaluate the energy consumption in WSN by using aggregation mechanism.This paper also shows that energy consumption of an aggregation node increases so rapidly in the neighborhood of the sink node that these nodes will die and shorten the lifetime of the whole network.Secondly,a modified hierarchical data aggregation strategy in order to achieve balanced energy depletion by reduce the cluster head selection probability near the sink is proposed.Simulation results show that,this method can reduce the energy consumption efficiently for sensor networks.So,it can prolong the lifetime of the whole networks.福建省自然科学基金No.A0710021;集美大学优秀青年骨干教师基金资助(No.2008B002)---

Techniques and Applications in Wireless Mesh Networks

无线网状网(WMNs)由网状路由器节点和客户机节点组成,其中的网状路由器节点组成了无线网状网的网络骨干,其移动性很小。他们一起为无线网状网和其他常规无线网络的客户机节点提供网络的无线接入。WMNs技术结合了中心式控制的蜂窝网与分布式控制的无线自组织网的优点,可有效克服这两种技术的缺陷并显著提高无线网络的性能,已经成为下一代无线通信网络的研究热点之一。WMNs可为无线个域网、局域网、校园网、城域网的一系列应用提供高速无线宽带接入服务。虽然目前WMNs技术发展很快,但其协议栈各层仍存在许多有待研究的课题。首先简要介绍了无线网状网的结构与特点;随后重点分析了其主要的几个应用领域;最后探讨了WMNs各协议层的研究现状与关键技术,并分析了该技术存在的问题及未来的研究方向。Wireless Mesh Networks(WMN) consist of mesh routers and mesh clients,where mesh routers have minimal mobility and form the backbone of WMNs.They provide network access for both mesh and conventional clients.WMNs are anticipated to resolve the limitations and to significantly improve the performance of wireless Ad Hoc networks and mobile cellular networks.They are undergoing rapid progress and inspiring numerous deployments.WMNs will deliver wireless broadband services access for a large variety of applications in personal,local,campus,and metropolitan areas.Despite recent advances in WMNs,many research challenges remain in all protocol layers.This paper presents a detailed study on recent advances and application scenarios in WMNs,followed by discussing the system architectures and characteristics briefly.Finally,recent research and advanced techniques of each protocol layer are described,and some open issues are analyzed

Anti-jumming technology of the Bluetooth and analysis for the mechanism of coexistance is the wireless network in 2.4GHz frequency band

介绍了工作于2.4GHz的几种无线网络技术的特点,对其性能作了比较,并从噪声系数指标及抗同频干扰等方面分析了蓝牙的抗干扰性能,同时讨论了2.4GHz频段无线电设备的共存机制。The characteristics of several wireless network of 2.4GHz frequency band are introduced and the performance is compared. The anti-jamming performance of the Bluetooth is analyzed from the coefficient of the noise and the anti-jamming performance at same frequency, and the mechanism of coexistance of wireless equipments which work at 2.4GHz frequency band is discussed

Energy Saving Route Finding Mechanism in Underwater Acoustic Sensor Networks

提出了水声传感网中能量有效的路由方案.结合水声信道的特点对水下传感网中的能耗因素进行分析,得出给定源宿节点之间的距离时路径消耗总能量与中继节点数的关系.对定向扩散协议进行改进,在初始化阶段根据汇聚节点和邻居节点的地理信息,求出源节点到目的节点的理想的最优能量路径.仿真结果证明,该方案能减少洪泛,只需选择1条较优路径,有效地节省了能量.An energy-efficient routing scheme is presented for underwater acoustic sensor networks(UW-ASN).Firstly,the factors affecting energy consumption in UW-ASN are analyzed in light of underwater channels,the relationship between numbers of relay nodes and energy consumption is obtained for given source-destination distance.The directed diffusion routing scheme is modified in the initial diffusion phase to find the optimal route based on the geographic information between a sink node and its neighboring nodes.Simulation shows that the proposed scheme can reduce the flooding cost,select an energy-efficient route,and save more energy.国家自然科学基金项目(60672046);集美大学优秀青年骨干教师基金项目(2008B002

A Congestion-aware Cross-layer Routing Scheme of Ad Hoc Networks with Multi-rate Mechanism

利用跨层设计的思想,论文提出了一种自适应多速率机制下,基于节点信息的AdHoc路由算法。根据物理层SNR的测量,结合MAC层的信息进行延迟估计,引入一种新的路由度量来选择路径,避开拥塞,减少延迟,提高网络吞吐量,从而能改善网络的整体性能。This paper proposes a cross-layer routing scheme based on information monitored by nodes for Ad Hoc networks supporting multi-rate mechanism.A new routing metric is introduced to take SNR measure on physical layer and delay estimate on MAC layer into account.With this metric,the routing algorithm tends to choose routes with wider bandwidth,lower delay,and less congestion.It demonstrates that the proposed scheme improves the performance of Ad Hoc work.清华-高通无线通信研究中心资助项