基于Delaunay三角剖分的Ad Hoc网络路由算法

Delaunay三角剖分已广泛地应用于计算流体力学、统计学、气象学、固体物理学、计算几何学等多个领域.随着无线Ad Hoc网络的发展,一些研究者提出了可以保证网络任意节点对之间分组顺利传输的几何路由协议,而这些协议的网络基础拓扑同样可以用Delaunay三角剖分的思想来实现.提出了一种新型的用于发现移动节点间通信路径的在线路由算法GLNFR(greedy and local neighbor face routing).利用局部构造法,构造出局部化的Delaunay三角剖分作为网络的基础拓扑.在该网络拓扑中进行的GLNFR路由算法可以保证节点间分组的顺利传输,对网络变化具有更好的可扩展性和适应性.在NS(network simulator)模拟器上仿真了该路由算法.结果表明,在分组成功传输率和路由分组开销性能方面,这一在线路由协议要优于先前提出的一些几何路由协议.     

传感网中的动态Delauanay三角剖分算法

几何路由协议受益于局部Delaunay三角剖分，因为Delaunay三角剖分可以保证消息转发的可达性和限制路由长度的界。本文提出一种构造无线传感网中Delaunay三角剖分的局部算法。此算法不但考虑了静态情况，而且考虑了允许节点动态地加入和退出网络的动态情况。在静态情况和动态情况下，算法的通信开销都是O（nlogn）位。因此，此算法
法可以应用于节点可以动态加入和退出的无线传感网。本文还证明了算法的正确性。     

A Pre-Processed Cross Link Detection Protocol for geographic routing in mobile ad hoc and sensor networks under realistic environments with obstacles

In mobile ad hoc and sensor networks, greedy-face-greedy (GFG) geographic routing protocols have been a topic of active research in recent years. Most of the GFG geographic routing protocols make an ideal assumption that nodes in the network construct a unit-disk graph, UDG, and extract a planar subgraph from the UDG for face routing. However, the assumption of UDG may be violated in realistic environments, which may cause the current GFG geographic routing protocols to fail. In this paper, we propose a Pre-Processed Cross Link Detection Protocol, PPCLDP, which extracts an almost planar subgraph from a realistic network graph, instead of a UDG, for face routing and makes the GFG geographic routing work correctly in realistic environments with obstacles. The proposed PPCLDP improves the previous work of Cross Link Detection Protocol, CLDP, with far less communication cost and better convergence time. Our simulation results show that the average communication cost and the average convergence time of PPCLDP are, respectively, 65% and 45% less than those of CLDP. This makes PPCLDP more desirable for mobile ad hoc and sensor networks.     

一种能量感知的无线移动自组网路由协议

无线移动自组网中的大多数节点都是由有限寿命的电池来提供的,能量保护策略就成为设计网络协议的一个重要条件。提出一种能量感知的无线移动自组网路由协议,综合考虑了节点的剩余能量和路由跳数,有效保护网络中能量低的节点,减少了节点能量损耗,延长了网络的使用时间。该路由协议中采用了局部路由修复机制,减少了数据包丢失,提高了数据传输率。最后,仿真结果证明了协议的有效性。     

高动态航空自组网中考虑优先级的逐跳路由协议

针对航空自组网频繁的拓扑变化、网络断开的问题,提出一种考虑优先级的逐跳路由（priority concern hop-by-hop routing,PCHHR）协议。PCHHR依据运动方向优先、距离次之的原则选择下一跳路由节点,优先选择向目的节点运动的邻居作为下一跳节点,次优选择距离目的节点最近的邻居作为下一跳节点;区分数据报文的时延需求,优先转发时延约束小的数据。仿真结果表明,PCHHR在较低的控制开销和端到端时延下,总体数据分组投递率高于航空路由协议（aeronautical routing protocol,AeroRP）、贪婪转发路由和传统的端到端路由协议,提高了高实时性数据分组的投递率。     

大规模网络上基于图嵌入的可扩展路由方法

大规模网络上理想的路由方法必须同时具有较小的路由表和较短的路径.传统的最短路径路由算法只考虑优化路径,但是路由表需要维护到所有节点的路由信息,故路由表项数至少随网络规模线性增长,因此呈现较差的扩展性.针对基于图嵌入的可扩展路由进行了研究,提出将网络嵌入到由它的支撑图(spanner)导出的度量空间.利用真实网络普遍存在的小世界和无标度拓扑特征,提出了一种嵌入和路由方法——GEROUTE,它用源于高度节点的树形支撑图来构造嵌入,对节点分配较短的标记,使得节点在支撑图上的距离能够由标记推算出来,在节点标记定义的度量空间中使用贪心路由,而节点的路由表只需要存放邻居的标记.分析和仿真表明该路由方法在像Internet的这类图上能够取得比较理想的路由性能,与其他同类方法相比表现更好.     

UWSNs中基于深度的抑制空洞路由优化算法

针对传统的水下无线传感器网络(UWSNs)的位置路由存在路由空洞问题,提出了基于深度的抑制空洞路由(DSVR)的UWSNs路由协议.DSVR协议通过融合跳数、物理距离和邻居数多个指标决策路由.为了提高通信可靠和缓解路由空洞,DSVR协议选择具有最小跳数路径、最少邻居数的节点作为下一跳转发节点.同时,DSVR协议利用定时器抑制冗余数据包.仿真结果表明:提出的DSVR协议能有效地提高数据包传递率,并降低端到端传输时延以及能耗.     

DAWA: Defending against wormhole attack in MANETs by using fuzzy logic and artificial immune system

Mobile ad hoc networks (MANETs) are mobile networks, which are automatically outspread on a geographically limited region, without requiring any preexisting infrastructure. Mostly, nodes are both self-governed and self-organized without requiring a central monitoring. Because of their distributed characteristic, MANETs are vulnerable to a particular routing misbehavior, called wormhole attack. In wormhole attack, one attacker node tunnels packet from its position to the other attacker nodes. Such wormhole attack results in a fake route with fewer hop count. If source node selects this fictitious route, attacker nodes have the options of delivering the packets or dropping them. For this reason, this paper proposes an improvement over AODV routing protocol to design a wormhole-immune routing protocol. The proposed protocol called defending against wormhole attack (DAWA) employs fuzzy logic system and artificial immune system to defend against wormhole attacks. DAWA is evaluated through extensive simulations in the NS-2 environment. The results show that DAWA outperforms other existing solutions in terms of false negative ratio, false positive ratio, detection ratio, packet delivery ratio, packets loss ratio and packets drop ratio.     

双向路径重选的自组网负载均衡路由协议

基于跨层负载感知和双向路径重选的自组网负载均衡路由协议(CLBLR)在路由发现阶段和路由维护阶段,将整个路径中各节点MAC层的总平均估计时延和路径总业务流负载结合起来,共同作为路由选择和路由调整的重要依据,通过双向路径重选方法实现最优路径选择和网络业务流的均衡分布和均衡传输.协议通过禁止中间节点对路由请求进行应答和阻止不必要的路由请求分组,经由重负载中间节点转发,以保证路由发现时能够利用最新负载信息,并避免了节点在重负载情况下成为新建路由的中间节点,使协议具有一定的拥塞控制功能,以间接的方式实现了请求接纳控制.上述措施使分组传输路由很好地避免了拥塞节点,减少了网络瓶颈对网络性能的影响.仿真表明,CLBLR在分组丢失率、平均端到端时延和路由附加开销等方面具有良好性能,其优良的分布式控制特征能适应自组网的动态环境.     

无线 Ad hoc 网络和传感网络中基于位置的、可靠的无信标传输路由方法

Existing position-based routing algorithms, where packets are forwarded in the geographic direction of the destination, normally require that the forwarding node should know the positions of all neighbors in its transmission range. This information on direct neighbors is gained by observing beacon messages that each node sends out periodically. Several beaconless greedy routing schemes have been proposed recently. However, none of the existing beaconless schemes guarantee the delivery of packets. Moreover, they incur communication overhead by sending excessive control messages or by broadcasting data packets. In this paper, we describe how existing localized position based routing schemes that guarantee delivery can be made beaconless, while preserving the same routes. In our guaranteed delivery beaconless routing scheme, the next hop is selected through the use of control RTS/CTS messages and biased timeouts. In greedy mode, the neighbor closest to destination responds first. In recovery mode, nodes closer to the source will select shorter timeouts, so that other neighbors, overhearing CTS packets, can eliminate their own CTS packets if they realize that their link to the source is not part of Gabriel graph. Nodes also cancel their packets after receiving data message sent by source to the selected neighbor. We analyze the behavior of our scheme on our simulation environment assuming ideal MAC, following GOAFR+ and GFG routing schemes. Our results demonstrate low communication overhead in addition to guaranteed delivery.     

路标迭代提取和剔除的自适应空洞处理算法

针对无线传感器网络贪婪地理路由协议中的路由空洞问题,提出一种高效的基于路标迭代提取和剔除的自适应空洞处理算法.该算法中,当探测包贪婪转发遇到空洞时,在网络拓扑局部平面化的基础上,以左(右)手法则提取空洞边界并沿其逆(顺)时针周边模式双向转发,同时,分布式地进行路标的迭代提取和剔除,直到获取的路标使得后续的数据包依次以它们为中间目标节点进行传输而不再遇到空洞为止.仿真结果表明,该协议能够以较小的控制开销代价获得次最优的传输路径,极大地提高了路由协议的性能,可以应用于无法消除路由空洞的大规模无线传感器网络贪婪地理路由协议.     

一种基于图论的分布式移动传感器网络模型

本文给出了一种基于定位信息和图论的分布式传感器网络定位模型。用Delaunay三角剖分描述节点实体和它们的关系以及结点之间的信息传递和融合;用Voronoi图定义节点覆盖的区域。该模型可以克服现有系统基于固定的底层结构定位的缺点,大大提高传感器网络的灵活性。在所提到的模型基础上进行了网络的自组织仿真,结果良好。     

具有副本抑制能力的多跳无线网络路由协议

针对多跳无线网络中机会路由的副本传输问题,提出一种新的机会路由协议。提出的策略不再简单采用单跳广播的方式转发数据,而是通过节点间的距离确定转发开销,再让数据包携带下一跳候选节点信息并根据候选节点的ACK选择下一跳节点,从而保证了每个数据包只有一个候选节点进行转发。仿真结果显示,提出的方案能减少不必要的传输行为,有效改善了网络吞吐率。     

基于协商机制的无线传感器网络路由协议

针对事件驱动型无线传感器网络（WSNs）中存在的次生驱动等问题,提出了一种基于分布式协商机制的WSNs路由协议。该协议通过抑制冗余节点发送数据来减少网内流量。仿真结果表明：该协议能够有效减少事件汇报的时间,减少系统能量消耗。     

基于低占空比的机会汇聚树路由协议

针对无线传感器网络(WSN)中存在节点剩余能量不足而导致的路由失效问题,提出一种基于低占空比的汇聚树机会路由算法CTOR。在CTOR中,首先根据网络的传输质量需求确定路由候选节点集;然后,节点以广播方式向所有候选节点传输数据包,收到数据包的候选节点再以一定概率转发该数据包,转发成功的候选节点即为选定的路由节点。概率的引进保证了高数据传输质量与轻网络负载;同时,网关节点发送时间同步控制信息以达到全网时间同步的目的;节点根据固定占空比进行休眠切换,以减少节点的能量消耗,延长网络的生存周期。仿真实验表明,基于低占空比的协议可有效地避免网络空洞问题,延长网络的生存周期;同时,机会性的转发可以有效地提高数据包的成功接收率,降低网络的丢包率。     

自组网中一种基于跨层负载感知的按需负载均衡路由

本文提出了一种新的基于跨层负载感知的自组网负载均衡路由协议（CLLOR）。CLLOR在路由发现阶段和路由维护阶段将整个路径中各节点MAC层的总平均估计时延和路径总业务流负载结合起来共同作为路由选择和路由调整的重要依据,以实现网络业务流的均衡分布和均衡传输。协议通过禁止中间节点对路由请求进行应答和阻止不必要的路由请求分组经由重负载的中间节点转发,以保证路由发现时能够利用最新的负载信息,并避免了节点在重负载情况下成为新建路由的中间节点,使得协议具有一定的拥塞控制功能,以间接的方式实现了请求接纳控制。通过上述措施,可以很好地避免网络中出现拥塞节点,减少了网络瓶颈对网络性能的影响。仿真表明,CLLOR在分组丢失率、平均端到端时延和路由附加开销等方面具有良好的性能,其优良的分布式控制特征能适应自组网的动态环境。     

车载自组织网络中基于定向传播的自适应路由协议

数据分组在转发过程中需要在其转发范围内寻找一个中继节点进行转发。为了降低转发过程中寻找中继节点的复杂程度,减少从源节点到达目的节点的平均跳数,提出了一种车载自组织网络中基于定向传播的自适应路由协议(Adaptive Routing Protocol Based on Directional Transmission,ARPBDT)。该路由协议有两个关键参数:转发角度和平均每跳前进距离。首先为了缩小转发范围,设置一个始终朝着目的节点方向的转发角度,以减少转发范围内的节点数以及寻找中继节点的计算量;其次为了减少平均跳数,在转发范围内根据前进距离自适应地选择较优或次优的邻居节点作为中继节点进行转发。仿真结果表明,与OBDR相比,所提路由协议的平均跳数较少,平均每跳前进距离较大,能够使数据分组快速地到达目的节点。     

基于分段修复的区域路由协议

在自组网中,ZRP的域间路由维护策略使ZRP具有较多的丢包数目和较多的路由重发现次数。前者使ZRP的数据包投递率较低,从而使其可靠性较低;后者使ZRP的传输时延和路由开销较高。针对上述问题,提出一种基于分段修复的区域路由协议SRZRP(Segmented Repairment based Zone Routing Protocol)。在SRZRP中,每个节点通过维护一个基于域内拓扑结构的有向无环图来保存到达其域内每个节点的多条备份路由,尽量利用备份分段路由进行域间路由修复。理论分析表明,SRZRP具有较高的可靠性。仿真结果表明,SRZRP提高了数据包投递率,说明SRZRP提高了协议的可靠性;同时,SRZRP降低了平均端到端时延和路由开销。     

Link stability based multicast routing scheme in MANET

The group-oriented services are one of the primary application classes that are addressed by Mobile Ad hoc Networks (MANETs) in recent years. To support such services, multicast routing is used. Thus, there is a need to design stable and reliable multicast routing protocols for MANETs to ensure better packet delivery ratio, lower delays and reduced overheads. In this paper, we propose a mesh based multicast routing scheme that finds stable multicast path from source to receivers. The multicast mesh is constructed by using route request and route reply packets with the help of multicast routing information cache and link stability database maintained at every node. The stable paths are found based on selection of stable forwarding nodes that have high stability of link connectivity. The link stability is computed by using the parameters such as received power, distance between neighboring nodes and the link quality that is assessed using bit errors in a packet. The proposed scheme is simulated over a large number of MANET nodes with wide range of mobility and the performance is evaluated. Performance of the proposed scheme is compared with two well known mesh-based multicast routing protocols, i.e., on-demand multicast routing protocol (ODMRP) and enhanced on-demand multicast routing protocol (EODMRP). It is observed that the proposed scheme produces better packet delivery ratio, reduced packet delay and reduced overheads (such as control, memory, computation, and message overheads).     

多尺度形态滤波及弹性匹配技术在类星体谱线识别中的应用

本文提出了一种类星体谱线证认方法。首先针对特征为极值点的信号，研究了多尺度膨胀（腐蚀）关于极值点数的两种重要特性及其应用。其一是单调率特性，根据它自动选择滤波器尺度，有效地滤除脉冲噪声；另一种是单调性，它是＂从粗到精＂策略来重新恢复极值特征位置的理论基础。根据这些性质，对光谱进行多尺度膨胀（腐蚀）和特征恢复，以滤除脉冲噪声而不影响谱线特征。然后研究弹性匹配技术应用于谱线证认，并指出了匹配方法中参量的物理意义。该方法对其他一些应用领域也行之有效