基于ODMRP的分布式核心稳定路由算法

在无人机网络中,由于节点具有较强的移动性,对于组播路由的建立以及组播组的划分提出更高要求,一般的组播路由协议往往无法满足网络需求.为此,提出了一种基于ODMRP的分布式核心稳定路由算法.该算法结合了改进贪婪机制,根据路由状况对路径进行优化,为了降低源节点的数据处理负担,提出了分布式核心节点选择机制,将组播组的信息储存在多个核心节点中,同时释放了转发节点的储存空间.文章通过路由抢修机制,监控路由状态变化,对即将断裂的路由提前修复,保证了路径的有效性.仿真表明,该算法与标准的ODMRP算法及改进算法VCMP算法相比,能够优化传输路径,降低端到端时延,提高分组交付率,提升网络性能.     

自组织覆盖网络QoS组播动态路由优化研究

针对覆盖组播节点的动态特性,研究自组织覆盖网络带度和延时约束的组播动态路由问题,提出了动态覆盖组播路由算法AHMQ。组播树由目的节点驱动动态渐近形成,动态路由优化在通信过程中进行。协议是软状态的,仅要求节点维护局部状态信息,同时利用覆盖网络技术和无线媒质的广播能力,降低了网络负载,提高了重构能力。对算法进行了分析研究,通过实验验证了该算法具有较好的性能。     

改进的DSMCast区分服务组播方案

给出DSMCast区分服务组播的一个改进方案,该方案只封装组播树上核心节点的复制、转发等信息,边界节点可维护各自的本地组播状态信息,保持了原有DSMCast方案中简化核心节点的优点,减少每个组播分组扩展头部的封装信息量,提高组播分组的有效利用率。仿真实验表明,改进的方案优于DSMCast方案。     

GLFR：一种新的基于地理位置信息AdHoc网络路由算法

在经典的基于地理位置信息的Ad Hoc网络路由算法GPSR的基础上,为了提高数据分组成功传输率,提出了一种适用于无线网络的路由算法GLFR,该算法以RNG图作为无线网络的拓扑结构,利用节点中存储的邻节点位置信息和局部面上的节点位置信息实现了数据分组的转发,随着网络中节点数的增加以及节点移动性的增强,该路由算法具有良好的可扩展性和适应性.通过仿真可以看出GLFR算法在数据分组成功传输率方面具有良好的性能.     

带度约束的组播路由算法

在多媒体通信网的实际应用中 ,组播 (multicasting)技术日益重要 ,但由于节点处理信息的能力不同 ,有些节点并不具备组播能力 ,同时为保证网络负载平衡 ,有些节点的组播能力应有所限制 ,用节点的度约束来表示每个节点应具备的组播能力 ,研究在网络节点具有不同度约束情况下的组播路由问题 ,提出了一种解决这个问题的简单有效的启发式算法 ,该算法对实验的大多数网络能够找到解     

无线传感器网络比对广播时间同步算法

针对无线节点自身资源有限的特点,结合比对同步方法和广播方法,提出了一种低开销的比对广播时间同步算法(PBTS).该算法中,主节点通过与其广播域内任意一个从节点进行分组比对交互获得主从节点分组延迟时间,并利用无线信道的广播特性实现主节点广播域内所有节点的时间同步,减少了同步分组数量.同时该算法设计了分组延迟时间更新周期因子,增加了算法的可配置性,进一步减少了同步过程开销.性能分析表明该算法能有效的减少同步过程开销,并能获得较高的时间同步精度.最后通过实验验证了该算法的性能.     

一种在Ad Hoc网络中基于地理位置的节约能量的组播路由算法

在移动adhoc网络中,设计节约能量的组播路由算法是非常重要的,这是由于网络中的节点运行时所需要的能量来自于电池的有限供给。由于节点是可以移动的,这就要求节约能量的路由协议在本质上是分布式的,对于当前的节点状态是自适应的。论文提出一种基于地理位置的节约能量的组播路由算法,使得在满足带宽的同时,组播的能量消耗尽可能的少。其基本思想是:先由基本的组播算法生成一棵组播树,然后由组播树的每个非叶子节点根据其邻居节点的地理位置,动态地选择一些转发点,通过这些点以较小功率转发时可节约能量,以此优化组播树。     

基于局部信息的时延和时延差约束的组播路由

组播通信是从一个源节点同时向网络中的多个目的节点发送分组的通信服务,它一般提供一个以上的端到端的服务约束,实际的路由算法在应用时可以受到多重约束,解决这类问题的组播路由算法是NP完全的。在研究了构建组播树的相关算法后,提出了一种新的时延和时延差约束的低代价组播路由算法-DDVMC。该算法采用基于贪婪策略的Dijkstra最小生成树算法,利用局部信息来构建低代价组播树,很好地平衡了树的代价、时延和时延差。仿真表明,该算法能正确地构造出满足约束的组播树,同时还具有较低的代价和计算复杂度。     

采用Hull树的贪婪地理位置路由算法的设计

地理位置路由算法是指借助节点获得的地理位置信息进行无线传感网络中的路由发现与数据转发工作。本文提出一种基于Hull树的贪婪地理位置路由算法——Greedy Hull Tree Geographic Routing(GHTGR)。通过图形学中凸包的概念,在网络初始阶段分布式地在各节点上建立Hull树以探查网络局部拓扑结构;同时在数据分组的路由转发阶段,通过Hull树内的搜索,寻找下一跳转发节点,完成数据分组的转发传输。通过仿真实验表明,与现有地理位置路由算法相比,该算法能够正确地寻找数据转发路径,有效地减少网络能耗,提高网络传输性能。     

集中式网络编码组播路由算法

从提高组播容量和降低组播延迟入手,提出了一种集中式网络编码循环增广组播路由算法(centralized network coding cycle augmented multicast routing algorithm,NCCA),从而进一步提高了组播通信的传输速率。首先各节点通过广度优先搜索(breadth first search,BFS)算法遍历链路状态分组获得整个网络的拓扑信息,以Dijkstra算法为基础增广每个信宿节点的路由集,然后选出最优路由集,最后将所有信宿节点的路由集进行组合,得到组播组的整体路由。通过对算法进行理论分析及仿真实验,证明了NCCA组播路由算法在较稳定的网络上能进一步提高组播通信的传输速率。     

An enhanced framework for providing multimedia broadcast/multicast service over heterogeneous networks

Multimedia broadcast multicast service （MBMS） with inherently low requirement for network resources has been proposed as a candidate solution for using such resources in a more efficient manner. On the other hand, the Next Generation Mobile Network （NGMN） combines multiple radio access technologies （RATs） to optimize overall network performance. Handover performance is becoming a vital indicator of the quality experience of mobile user equipment （UE）. In contrast to the conventional vertical handover issue, the problem we are facing is how to seamlessly transmit broadcast/multicast sessions among heterogeneous networks. In this paper, we propose a new network entity, media independent broadcast multicast service center （MIBM-SC）, to provide seamless handover for broadcast/multicast sessions over heterogeneous networks, by extensions and enhancements of MBMS and media independent information service （MIIS） architectures. Additionally, a network selection scheme and a cell transmission mode selection scheme are proposed for selecting the best target network and best transmission mode. Both schemes are based on a load-aware network capacity estimation algorithm. Simulation results show that the pro- posed approach has the capability to provide MBMS over heterogeneous networks, with improved handover performance in terms of packet loss rate, throughput, handover delay, cell load, bandwidth usage, and the peak signal-to-noise ratio （PSNR）.     

MDCE路由算法的分析与改进

延迟容忍网络中基于位置的地理路由算法使用节点自我采集的GPS信息进行下一跳中继结点的选择,而节点的移动性会导致节点的实际位置在时刻改变,相对位置节点的移动方向信息比地理位置信息具有更好的稳定性。文献[1]提出的MDCE路由算法网络负载率和丢包率很高,且由于DTN网络的特殊性,难以拥有多个相邻节点。对MDCE路由算法进行分析与改进,降低中继节点数、规避消息副本向来的方向传输。仿真结果表明,改进后的MDCE路由算法的网络负载率和丢包率明显降低,实用性更强。     

交换式以太网中连续实时流媒体的可靠组播

对目前局域网中连续实时流媒体的可靠组播进行了研究.首先分析了局域网影响可靠组播的几个特性,然后设计了局域网内针对连续实时流媒体的基于重传的可靠组播传输协议.协议中的错误恢复首先利用接收者检测包丢失,同时采用NAK(negative acknowledgment)抑制减少产生的反馈包;然后发送者根据NAK请求重传已经丢失的数据包;接收者根据本地播放时间限制决定接收或者丢弃迟到的重传包.实验结果和性能分析证明了该可靠组播协议的可靠性和有效性.     

无线传感网络的广播时效性研究

无线传感网络的节点采用时隙CSMA/CA协议获取信道并广播数据.为了度量信息广播的时效性,提出了广播信息年龄(broadcast age of information,bAoI)的概念.广播信息年龄等于当前时刻减去刚刚广播成功的那个数据包的生成时刻.bAoI量化了每个节点的数据包的新鲜度,并且描述了节点在网络上快速广播...     

不可靠通信环境下无线传感器网络最小能耗广播算法

在实际的通信环境中,由于噪声、报文冲突、信号衰减等因素的影响,无线传感器网络节点间信息交换往往是不可靠的.广播是无线传感器网络中广泛使用的操作,如何在不可靠通信环境下实现能量高效的广播算法,对提高整个无线传感器网络的性能具有重要的理论和应用价值.研究了不可靠通信环境下的无线传感器网络最小能耗广播问题,首先,分析了相邻节点之间最小能耗通信模型,并给出了保证节点接收概率不低于P^*的最优发送半径;然后,讨论了多跳转发策略与节点位置信息之间的关系.在此基础上,提出了一种基于PSO的最小生成树广播算法,通过优化各节点的发送半径,在保证所有节点都能以不低于P^*的概率接收到广播数据包的前提下,实现广播操作的总能耗最小.实验结果表明：所提出的广播算法不仅可使每一个节点的接收概率不小于P^*,而且广播总能耗比改进后的BIP算法要小,具有较好的性能.     

A Novel Gradient Boosted Energy Optimization Model (GBEOM) for MANET

Mobile Ad Hoc Network (MANET) is an infrastructure-less network that is comprised of a set of nodes that move randomly. In MANET, the overall performance is improved through multipath multicast routing to achieve the quality of service (quality of service). In this, different nodes are involved in the information data collection and transmission to the destination nodes in the network. The different nodes are combined and presented to achieve energy-efficient data transmission and classification of the nodes. The route identification and routing are established based on the data broadcast by the network nodes. In transmitting the data packet, evaluating the data delivery ratio is necessary to achieve optimal data transmission in the network. Furthermore, energy consumption and overhead are considered essential factors for the effective data transmission rate and better data delivery rate. In this paper, a Gradient-Based Energy Optimization model (GBEOM) for the route in MANET is proposed to achieve an improved data delivery rate. Initially, the Weighted Multi-objective Cluster-based Spider Monkey Load Balancing (WMC-SMLB) technique is utilized for obtaining energy efficiency and load balancing routing. The WMC algorithm is applied to perform an efficient node clustering process from the considered mobile nodes in MANET. Load balancing efficiency is improved with a higher data delivery ratio and minimum routing overhead based on the residual energy and bandwidth estimation. Next, the Gradient Boosted Multinomial ID3 Classification algorithm is applied to improve the performance of multipath multicast routing in MANET with minimal energy consumption and higher load balancing efficiency. The proposed GBEOM exhibits ∼4% improved performance in MANET routing.     

Optimized broadcasting and multicasting protocols in cut-throughrouted networks

This paper addresses the one-to-all broadcasting problem and the one-to-many broadcasting problem, usually simply called broadcasting and multicasting, respectively. Broadcasting is the information dissemination problem in which a node of a network sends the same piece of information to all the other nodes. Multicasting is a partial broadcasting in the sense that only a subset of nodes forms the destination set. Both operations have many applications in parallel and distributed computing. In this paper, we study these problems in both line model, and cut-through model. The former assumes long distance calls between nonneighboring processors. The latter strengthens the line model by taking into account the use of a routing function. Long distance calls are possible in circuit-switched and wormhole-routed networks, and also in many networks supporting optical facilities. In the line model, it is well known that one can compute in polynomial time a [log₂n]-round broadcast or multicast protocol for any arbitrary network. Unfortunately such a protocol is often inefficient from a practical point of view because it does not use the resources of the network in a balanced way. In this paper, we present a new algorithm to compute broadcast or multicast protocols. This algorithm applies under both line and cut-through models. Moreover, it returns protocols that efficiently use the bandwidth of the network. From a complexity point of view, we also show that most of the optimization problems relative to the maximization of the efficiency of broadcast or multicast protocols in terms of switching time or vertex load are NP-complete. We have, however, derived polynomial efficient solutions for tree-networks     

Dynamic route maintenance for geographic forwarding in mobile ad hoc networks

Traditional route maintenance requires mobile nodes periodically exchange beacon messages with their neighbors in geographic forwarding algorithms. The interval at which these nodes broadcast their beacon messages is typically fixed. However, determining an appropriate value for this interval is challenging. A longer interval reduces the number of beacons needed, but may result in significant location errors. Conversely, a shorter interval guarantees more accurate location information, but induces heavier control overheads. Additionally, since a fixed value is assigned to the lifetime of each routing entry, the forwarding algorithm cannot adapt well to different mobility environments. Therefore, this paper presents a dynamic route maintenance algorithm (DRM) for beacon-based geographic routing. In the approach, the mobile nodes dynamically adjust their beacon intervals based on their speed of movement. Moreover, the routing information can be well managed using the mobility prediction. The simulation results show that DRM not only significantly decreased the routing overheads in a low mobility scenario but also guaranteed the high quality packet delivery in high mobility environments.