基于节点运动的机会网络路由算法

机会网络利用节点移动带来的接触机会传输数据,数据在节点运动过程中捎带转发,保证了节点独立性,但会给数据传输带来影响.以节点的运动特性为切入点,设计了基于运动的机会网络路由算法.综合考虑数据传输、数据内容以及应用需求等因素,设计了数据转发优先级评价模型,结合节点活动区间划分方案制定数据传输规则;设计了差异化副本传输策略,在数据传输效率和系统开销之间取得折衷;考虑了节点活动范围、中心度及能量水平,构建了运动自由度函数评估节点运动水平.在此基础上设计了效用函数,选择中继节点转发数据.仿真结果表明,该算法能够在满足传输要求的同时限制网络开销,提高分组投递率,降低传输时延.     

水声传感网中基于网络编码的协作传输算法

为提高水下数据传输可靠性,本文在随机线性网络编码的基础上提出一种协作数据传输算法。首先,为源节点寻找数据转发链路,让数据通过多条链路进行转发;其次,使用网络编码方法对数据包进行编码,避免转发节点转发重复数据包;最后,对各个节点的数据包传输时隙进行调度,避免节点间信号冲突。仿真结果表明,本文提出的算法在一定程度上提高了网络信道利用率和数据传输可靠性,且具有较好的稳定性。     

有限马尔可夫链的水声传感器网络协作中继算法

针对水下传感器网络误码率高,能量效率低等问题,基于有限马尔可夫链状态空间分析,提出一种水声传感器网络协作中继算法。该算法采用马尔可夫链状态空间获取协作节点的误码率和能量的状态转移概率。基于能量策略对中转节点进行判定,使网络优先保障对已采集的数据进行传输,提升传输效率。提出基于最佳中继选择的协作节点状态评价函数,使网络优先选择评价结果最高的协作节点作为转发节点,减少数据传输过程中的误码率和能量损耗。实验仿真结果表明,该算法相比基于增强型能源平衡数据传输的水声网络协议及水下网络自适应路由协议,数据包平均成功投递率分别提升了2.3%和3.1%,网络能量效率分别提升了10.6%和5.8%,在提升数据传输效率和减少网络能耗上具有较好效果。     

能耗自选演进机制的延迟容忍网络路由算法

为了提高延迟容忍网络中数据投递过程节点能耗管理效率、改善数据在网络中的转发效率等,本文引入节点间能耗博弈模型,进而提出了一种基于能耗自选演进机制的延迟容忍网络路由算法（Efficient Routing Mechanism for Delay Tolerant Network based on Energy Consumption Strategy）,根据泛洪路由策略设计数据投递机制,数据在网络中转发时,节点依据自身能量剩余状态制定相应的投递操作,对首先将数据投递至目的节点的中间节点予以一个单位的奖励,利用节点策略博弈模型选取合理的数据投递操作,以此改善节点转发数据能量消耗,从而提高数据投递能量管理效率,并提高数据转发效率.仿真验证表明：所提算法与对照算法相比在数据投递率、传输时延、网络开销等性能指标上表现出较好效果.     

Ad Hoc网络机会路由协议转发候选集算法的研究

应用于无线Ad Hoc网络中的机会路由,结点转发候选集的选取通常是基于最短路径期望传输次数,没有充分考虑无线网络结点进行数据转发的广播特性。以多路径期望传输次数为路由量度,提出一种最优转发候选集算法MCET。实现对无线网络中除了目的结点以外的所有结点选取考虑多路径转发期望值的转发候选集,并在按照结点选取的顺序依次优先排列优先级。仿真结果表明,比较于传统的基于最短路径期望传输次数的机会路由,应用了最优转发候选集算法的机会路由明显减少了数据的平均传输次数,增加了数据报文的成功传输率。     

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。     

基于移动医疗大数据平台下深度最优匹配算法的机会网络转发机制

在移动医疗大数据平台上,机会网络的数据转发存在着严重的资源浪费现象,以至于影响了平台的正常运行。基于这种认识,本文提出了一种基于深度最优匹配算法的机会网络转发机制,可以通过比较节点数据找到最优的数据传输路径,能够提高数据的转发效率。而经过验证,该种算法能够减少冗余数据,可以显著提升网络数据传输成功率。     

基于时序感知优化机制的无线传感网数据投递算法

为解决无线传感网数据投递算法存在的链路选取质量不高,且节点重投递现象严重,容易降低网络传输质量等不足,本研究提出一种基于时序感知优化机制的无线传感网数据投递算法。首先,算法通过感知节点接近状态的时序情形,设计了基于时序效应的链路筛选方法,通过优选中继节点的方式提升链路投递率,以降低网络链路丢包概率,进而增强数据传输质量。随后,算法通过自感知方式获取节点转发数据,设计了基于投递优选的拥塞控制方法,以提高多跳链路的稳健性,降低节点碰撞效应带来的拥塞现象,进而改善网络数据投递质量。仿真实验结果表明,本研究算法与当前无线传感网中常用的虫洞-路径投递算法和神经卷积深度投递算法相比,能够显著降低网络平均投递时延,且网络累计拥塞频次较低,网络数据投递成功率较高,具有较高的实际部署价值。     

无线传感器网络中基于拍卖博弈的数据包转发算法

在无线传感器网络中,为了提高能量的利用率和增强数据包转发的可靠性,设计了PFAG（Packet Forwarding Algorithm Based on Auction Game）算法。该算法将数据包转发过程看作一种多阶段拍卖博弈过程,首先,网络中的节点根据拍卖博弈模型中的标价函数给出相应标价,然后基于双方博弈阶段最大化自己收益的原则,源节点可选出最佳的转发节点,从而找出最优的包转发策略。仿真结果表明,PFAG算法可有效的降低和平衡网络能耗,具备传输可靠性高和适应网络规模变化性强的特点。     

基于流间编码的机会路由转发节点集选择算法

针对流间网络编码与机会路由结合时编码机会与转发节点数目之间的矛盾,提出一种基于流间网络编码的机会路由转发节点集选择算法FNSA。采用发送可变长报文探测包的方法获取更加准确的数据包成功发送概率,定量分析链路数据成功传输概率、传输次数和转发节点的个数之间的关系,确立最佳转发节点数目,选取最佳转发节点集。将该算法应用于编码感知机会路由协议CAOR,仿真实验结果表明,采用定长探测包时(α=0),网络吞吐量性能有约5%的提升;采用可变长报文探测包时(α=0.1),网络吞吐量性能有约9%的提升。     

Routing with multi-level cross-community social groups in mobile opportunistic networks

Mobile opportunistic networks (MONs) are intermittently connected networks, such as pocket switched networks formed by human-carried mobile devices. Routing in MONs is very challenging as it must handle network partitioning, long delays, and dynamic topology. Flooding is a possible solution but with high costs. Most existing routing methods for MONs avoid the costly flooding by selecting one or multiple relays to deliver data during each encounter. How to pick the “good” relay from all encounters is a non-trivial task. To achieve efficient delivery of messages at low costs, in this paper, we propose a novel group-based routing protocol in which the relay node is selected based on multi-level cross-community social group information. We apply a simple group formation method to both historical encounters (social relationships in physical world) and/or social profiles of mobile users (social relationships in social world) and build multi-level cross-community social groups, which summarize the wide range of social relationships among all mobile participants. Our simulations over several real-life data sets demonstrate the efficiency and effectiveness of the proposed method by comparing it with several existing MON routing schemes.     

基于移动Agent的无线多媒体传感器网络QoS路由算法

无线多媒体传感器网络(WMSNs)的主要特点包括资源有限、时延敏感和数据冗余性高。此外,音视频数据流传输所需的带宽是多媒体传感器节点所能承受的最大传输带宽的几倍。上述因素使得WMSNs的QoS 路由成为一个亟待解决的关键技术问题。鉴于此,首先通过基于等差数列的非均匀分簇算法对网络区域进行划分,然后在此网络拓扑上,提出一种基于移动Agent的WMSNs的QoS路由算法(MAQR)。MAQR由路由发现和数据传输两个阶段组成。在路由发现阶段,采用移动代理技术完成多路径路由发现。在数据传输阶段,采用多优先级多路径传输模型把数据流进行分类,并利用流量预测算法实现网络的负载均衡。最后,在NS-2平台上实现了MAQR,通过与同类算法进行仿真比较,发现MAQR较之同类算法能够明显地提高音视频传输的服务质量。此外,MAQR算法比同类算法的能耗更低。     

机会网络路由协议

在机会网络中由于网络稀疏、节点移动和通信范围等因素的影响,有可能出现网络分裂或节点脱网,源节点和目的节点之间不一定存在完整的端到端路径,这为路由协议的设计带来巨大挑战,此问题近年来引起了研究人员越来越多的关注。首先介绍了机会网络的基本概念、体系结构和特点等;然后阐述了机会网络路由协议研究的进展,概括了机会网络路由协议中的新机制,对现有路由协议进行分类并详述它们的基本原理;通过比较对各种协议的特点进行分析阐述,最后给出未来研究的方向。     

移动边缘计算中基于视频内容协作分发的联合激励机制

随着智能设备存储和传输能力的提升,用户可通过设备—设备连接共享视频服务,在移动边缘网络中实现视频内容协作分发.然而,现有架构缺少合适的激励机制解决中继传输节点经济收益受损和本地数据泄露问题.针对视频内容边缘协作分发系统存在的问题,提出适用于多码率编码视频的联合安全和经济激励机制,并对该机制的差分隐私性、近似诚实性和个体理性进行了理论上的证明.最后由实验数据表明,该机制能有效保护参与用户的个体利益,提高视频服务总体效益.     

Real-time data dissemination in mobile peer-to-peer networks

Mobile peer-to-peer networks have found many uses such as streaming of audio and video data. There are circumstances, such as emergency situations and disaster recovery, when real-time delivery is a fundamental requirement. The problem is challenging due to the limited network capacity, the variable transmission rates and the unpredictability with respect to the network conditions in the mobile peer-to-peer network.In this paper we address the problem of real-time data dissemination of multimedia streams in mobile peer-to-peer networks. Four routing algorithms are proposed based on a packet's deadline, priority or a combination of these metrics. They are simulated under different setups in a mobile peer-to-peer network with Bluetooth connectivity and nodes broadcasting audio and video streams using different priorities. We compare the performance of the algorithms using a number of metrics. Detailed experimental results are presented. Based on these results, propositions on the usage of the algorithms and the design of network requirements are presented.     

Improving routing protocol performance in delay tolerant networks using extended information

Delay tolerant networks (DTNs) are wireless mobile networks that do not guarantee the existence of a path between a source and a destination at any time. When two nodes move within each other’s transmission range during a period of time, they can contact each other. The contact of nodes can be periodical, predictable and nonpredictable. In this paper, we assume the contact of nodes is nonpredictable so that it can reflect the most flexible way of nodes movement. Due to the uncertainty and time-varying nature of DTNs, routing poses special challenges. Some existing schemes use utility functions to steer the routing in the right direction. We find that these schemes do not capture enough information of the network. Thus, we develop an extended information model that can capture more mobility information and use regression functions for data processing. Experimental results from both our own simulator and real wireless trace data show that our routing algorithms based on the extended information model can increase the delivery ratio and reduce the delivery latency of routing compared with existing ones.     

无线多跳网络中基于博弈论的协作激励机制研究

无线多跳网络中网络传输性能容易受到自私节点的影响。本文首先对目前的节点协作激励机制进行了总结,然后,针对分簇路由中簇间路由场景,运用博弈论中非合作博弈的思想,建立博弈模型以激励簇内节点通过协作通信的方式帮助簇头进行数据包的转发,最后给出了基于非合作博弈的激励机制中纳什均衡解的求解过程。     

Development and Verification of Simulation Model Based on Real MANET Experiments for Transport Layer Protocols （UDP and TCP）

There is a lack of appropriate guidelines for realistic user traces, mobility models, routing protocols, considerations of real-life challenges, etc. for general-purpose mobile ad hoc networks (MANET). In this paper, four laptops are used in an open field environment in four scenarios to evaluate the performances of Internet control message protocol (ICMP) based ping and transmission control protocol (TCP) based streaming video applications using optimised link state routing (OLSR) implementation in an IEEE 802.11g wireless network. Corresponding simulations are developed in Network Simulator ns-2 by setting simulation parameters according to the real experiments. Difficulties faced to regenerate real-life scenarios have been discussed and the gaps between reality and simulation are identified. A setup guideline to produce realistic simulation results has been established.     

Strengthen nodal cooperation for data dissemination in mobile social networks

Data dissemination is a challenging issue in mobile social networks. It aims at increasing the overall delivery ratio and reducing the overall delivery delay. Most of the existing works assume all the users in a network are cooperative, i.e., the users are willing to carry the messages that they are not interested in while the nodes they meet maybe. In reality, the behaviors of each individual are naturally selfish, especially when the resources they have and they can access are limited. A data dissemination protocol cannot be pragmatic unless the selfishness is considered. This work proposes an incentive scheme to stimulate the users in a network to be more cooperative. Credits are the stimulus to encourage users to be more cooperative for data dissemination. We evaluate each node’s ability to fetch messages of a specific kind of interest and every single user can rent other nodes to help with obtaining the interested messages by paying credits. Extensive simulations on real traces are carried out to evaluate the proposed incentive scheme.     

A routing defense mechanism using evolutionary game theory for Delay Tolerant Networks

Delay Tolerant Networks (DTNs) often suffer from intermittent disruption due to factors such as mobility and energy. Though lots of routing algorithms in DTNs have been proposed in the last few years, the routing security problems have not attracted enough attention. DTNs are still facing the threats from different kinds of routing attacks. In this paper, a general purpose defense mechanism is proposed against various routing attacks on DTNs. The defense mechanism is based on the routing path information acquired from the forwarded messages and the acknowledgment (ACK), and it is suitable for different routing schemes. Evolutionary game theory is applied with the defense mechanism to analyze and facilitate the strategy changes of the nodes in the networks. Simulation results show that the proposed evolutionary game theory based defense scheme can achieve high average delivery ratio, low network overhead and low average transmission delay in various routing attack scenarios. By introducing the game theory, the networks can avoid being attacked and provide normal transmission service. The networks can reach evolutionary strategy stable (ESS) under special conditions after evolution. The initial parameters will affect the convergence speed and the final ESS, but the initial ratio of the nodes choosing different strategies can only affect the game process.