一种基于马尔可夫模型的加速ICN路径收敛性的方法

在新型的内容中心网络(Information-Centric Networking, ICN)多宿主场景中,主机的标识和地址分离,允许数据包中携带多个地址。多目的地址的数据包在匹配路由表之后获得多个转发端口,在每跳具有路径选择的能力,可以根据网络的动态进行路径调整。然而,这种转发方法打破了根据路由表最短路径转发规则,数据包可能在网络中来回跳动而不能尽快收敛到目的地。本文提出一种基于马尔可夫模型的多地址裁剪方法,该模型能根据历史地址裁剪状态信息进行裁剪决策,从而提高路径的收敛性。实验结果表明该方法与基准方法相比,在保证传输速率几乎相同的同时,平均跳数减少约16%,在路径收敛性方面得到了改善。     

Hash caching mechanism in source-based routing for wireless ad hoc networks

In mobile ad hoc network (MANET), on-demand routing protocols are proposed for establishing a route in a distributed manner only when a source host originates a data packet addressed to the destination host. In source-based routing (SBR) protocols, route discovery usually raises a large number of request packets for exploring the current state of the network, but it also performs the collection of useful information for future routing decisions. How to store and manage this collected information in the limited size of cache in order to improve routing performance is still an open issue in the development of an SBR scheme. This paper proposes a novel hash caching mechanism and distributed hashing routing methods to store, utilize, and manage the cached routes in order to improve cache capacity, routing performance, and network throughput. The experimental results indicate that the proposed mechanism offers high cache capacity, efficient route discovery, and good throughput for the MANET.     

基于时延期望的车载自组织网络机会路由算法

针对车载自组织网络中,车辆随机运动的环境下源节点、目的节点均为运动中的车辆时数据传输效率低下的问题,提出了一种基于时延期望的机会路由算法.算法融合了概率论和统计学知识,综合考虑目的节点轨迹预测和数据时效性两方面需求,得到时延期望参数,以该参数作为整个数据传输过程中每一次数据转发中继节点选择标准,保证数据能够及时、有效地由移动中的源节点转发至移动中的目的节点.     

基于分组转发状况的车载自组织网络路由算法研究

路由协议算法是车载自组织网络的一个重要研究方向.目前多数车载自组织网络路由协议算法根据一些间接表征因素(如源到目的节点的最短距离、车流量密度等)来判断最优转发路径,但是这些表征因素还都停留在理论假设阶段,能否反应真实的路况、表示实事上最优的路径并无定论.提出一种基于分组转发状况的车载自组织网络路由协议算法,旨在根据分组...     

Routing using reinforcement learning in vehicular ad hoc networks

In vehicular ad hoc networks (VANETs), the frequent change in vehicle mobility creates dynamic changes in communication link and topology of the network. Hence, the key challenge is to address and resolve longer transmission delays and reduced transmission stability. During the establishment of routing path, the focus of entire research is on traffic detection and road selection with high traffic density for increased packet transmission. This reduces the transmission delays and avoids carry-and-forward scenarios; however, these techniques fail in obtaining accurate traffic density in real-time scenario due to rapid change in traffic density. Thus, it is necessary to create a model that efficiently monitors the traffic density and assist VANETs in route selection in an automated way with increased accuracy. In this article, a novel machine learning architecture using deep reinforcement learning (DRL) model is proposed to monitor and estimate the data essential for the routing protocol. In this model, the roadside unit maintains the traffic information on roads using DRL. The DRL predicts the movement of the vehicle and makes a suitable routing path for transmitting the packets with improved transmission capacity. It further uses predicted transmission delays and the destination location to choose the forwarding directions between two road safety units (RSUs). The application of DRL over VANETs yields increased network performance, which provides on-demand routing information. The simulation results show that the DRL-based routing is effective in routing the data packets between the source and destination vehicles than other existing method.     

A multi-path mechanism for reliable VoIP transmission over wireless networks

With the advances in audio encoding standards and wireless access networks, voice over IP (VoIP) is becoming quite popular. However, real-time voice data over lossy networks (such as WLAN and UMTS), still posses several challenging problems because of the adverse effects caused by complex network dynamics. One approach to provide QoS for VoIP applications over the wireless networks is to use multiple paths to deliver VoIP data destined for a particular receiver. This paper introduced cmpSCTP, a transport layer solution for concurrent multi-path transfer that modifies the standard stream control transmission protocol (SCTP). The cmpSCTP aims at exploiting SCTP’s multi-homing capability by selecting several best paths among multiple available network interfaces to improve data transfer rate to the same multi-homed device. Through the use of path monitoring and packet allotment techniques, cmpSCTP tries to transmit an amount of packets corresponding to the path’s ability. At the same time, cmpSCTP updates the transmission strategy based on the real-time information of all of paths. Using cmpSCTP’s flexible path management capability, we may switch the flow between multiple paths automatically to realize seamless path handover. The theoretical analysis evaluated the model of cmpSCTP and formulated optimal traffic fragmentation of VoIP data. Extensive simulations under different scenarios using OPNET verified that cmpSCTP can effectively enhance VoIP transmission efficiency and highlighted the superiority of cmpSCTP against the other SCTP’s extension implementations under performance indexes such as throughput, handover latency, packet delay, and packet loss.     

一种基于部分网络编码的无线网络机会路由算法

结合机会路由和网络编码两项新技术各自的优势,提出了一种新的基于部分网络编码的机会路由算法(Opportunistic Routing Algorithm for Wireless Network Based on Partial Network Coding,ORAPNC)。为了避免数据包分叉传输,同时利于执行转发节点间协调机制,ORAPNC首先以期望传输次数作为路由度量建立一条固定路由,并将候选转发节点集中在这条固定路径附近;为了充分减小网络中的冗余数据包,ORAPNC采用一种新的转发节点间协调机制(Forwarding Nodes Coordination Mechanism,FNCM)来实现每跳的数据包传输。仿真结果表明,与其他相关路由协议相比较,ORAPNC可以有效提高网络吞吐量,减小目的节点解出原始数据包的平均时延。     

Maximum data delivery probability-oriented routing protocol in opportunistic mobile networks

Some recent studies utilize node contact patterns to aid the design of routing protocol in Opportunistic Mobile Networks (OppNets). However, most existing studies only utilize one hop contact information to design routing protocol. In order to fully utilize nodes’ collected contact information to improve the performance of data forwarding, in this paper we focus on exploiting node contact patterns from the multi-hop perspective. We first give the definition of opportunistic forwarding path, and propose a model to calculate the maximum data delivery probability along different opportunistic forwarding paths. Second, based on the maximum data delivery probability, we propose a novel approach to improve the performance of data forwarding in OppNets based on two forwarding metric. The proposed forwarding strategy first manages to forward data copies to nodes have higher centrality value at the global scope. Afterwards, maximum data delivery probability to the destination is evaluated, to ensure that data is carried and forwarded by relays with higher capability of contacting the destination. Finally, extensive real trace-driven simulations are conducted to compare the proposed routing protocol with other existing routing protocols in terms of delivery ratio and delivery cost. The simulation results show that our proposed routing protocol is close to Epidemic Routing in terms of delivery ratio but with significantly reduced delivery cost. Additionally, our proposed routing protocol outperforms Bubble Rap and Prophet in terms of delivery ratio, and the delivery cost of our proposed routing protocol is very close to that of Bubble Rap.     

Ergodic secrecy rate of two-user MISO interference channels with statistical CSI

This paper considers a two-user multiple-input single-output （MISO） interference channel with confidential messages （IFC-CM）, where the beamforming vectors at the two transmitters are jointly optimized using the closed-form Pareto-optimal parameterization. We prove that artificial noise cannot improve the secrecy rate performance, and coordinated beamforming is secrecy-rate optimal which is achieved by agreeing on the parameters between the two transmitters. We analyze the feasible set of the beamforming parameters that guarantees positiveness of the secrecy rates when the transmitters know only statistical CSI, and then analysis in the ergodic secrecy rate region is discussed. More importantly, we derive the closed form of the ergodic secrecy rates and illustrate the Pareto-optimal structure of the beamforming vectors.     

一种MANET网络的位置辅助路由协议

Ad-Hoc网络（即MANET）由于节点的移动，导致路由频繁变化．基于位置辅助路由协议（LAR1），本文提出了一种带路径优化的增强LAR1协议（ELAR1）．节点通过在接收到的路由请求包中获取其携带的其它转发节点位置信息，提高发起路由请求时预知目的节点位置的几率，降低网络内路由广播包的数量．针对路由路径中可能存在非最短路由，利用位置信息对获得的路由进行路径优化．仿真结果表明，ELAR1比LAR1有较低的路由请求开销、较高的包投递率和较低的端到端延迟．     

Energy-aware routing for delay-sensitive underwater wireless sensor networks

The energy reduction is a challenging problem in the applications of underwater wireless sensor networks （UWSNs）. The embedded battery is difficult to be replaced and it has an upper bound on its lifetime. Multihop relay is a popular method to reduce energy consumption in data transmission. The energy minimum path from source to destination in the sensor networks can be obtained through the shortest path algorithm. However, because of the node mobility, the global path planning approach is not suitable for the routing in UWSNs. It calls for an energy-efficient routing protocol for the high dynamic UWSNs. In this paper, we propose the modified energy weight routing （MEWR） protocol to deal with the energy-efficient routing of delay- sensitive UWSNs. MEWR is a low flooding routing protocol. It can tolerate the node mobility in UWSNs and achieve a low end-to-end packet delay. MEWR can provide lower energy consumption than the existing low delay routing protocols through the dynamic sending power adjustment. The simulation results demonstrate the effectiveness of MEWR.     

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。     

Enforcing in-order packet delivery in system area networks with adaptive routing

Adaptive routing, which dynamically selects the route of packets, has been widely studied for interconnection networks in massively parallel computers and system area networks. Although adaptive routing has the advantage of providing high bandwidth, it may deliver packets out-of-order, which some message passing libraries do not accept. In this paper, we propose two mechanisms called (1) FIFO transmission and (2) couple limitation to guarantee in-order packet delivery in adaptive routing. Both of them limit packet injection at source hosts. The FIFO transmission completely avoids packet sorting at destination hosts, while the couple limitation uses a few buffers to sort packets at destination hosts. Evaluation results show that the FIFO transmission and the couple limitation achieve a similar throughput to that of a method equipped with huge (infinite) buffers enough to store all out-of-order packets at destination hosts under both synthetic traffic and NAS Parallel Benchmarks.     

Implementation of energy efficient circuit design using A* algorithm in embedded network

In wireless sensor network, the routing path plays a prominent role in network resource utilization. Since, the nodes in network are open to physical abuse an effective routing protocol is necessary to improve data reliability in network and to overcome node data link disconnection. In this paper, we propose to implement A*EEDDP (Energy Efficient Distributed Diffusion protocol) to improve data reliability and increase network lifetime. The A* algorithm determines the shortest routing path between source node and destination node. In addition, the routing path determine with respect to parameters such as energy consumed for communication, residual energy of nodes and the time over which the nodes can support the routing path. The combined A*EEDDP implement in testbed and performance evaluate interms of network lifetime, throughput, packet delivery ratio, energy efficiency and end to end delay. The A*EEDDP performs better compared to other algorithm and achieves higher packet delivery ratio of 97%.     

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.     

基于跳数计数的AODV路由协议优化

提出一种改进的路由协议HAODV。该协议在链路中断时,接收中断处的上游节点广播到目的节点的跳数,由于在一定时间内,节点的移动不会太远,因此能快速修复路由路径,同时利用到基础路径的跳数,限制路由信息广播及修复的区域,从而减少广播风暴。仿真结果表明,与AODV协议相比,该协议的包投递率更高,且平均延时及路径节点跳数更少。     

移动自组网基于路径维持概率的按需路由协议

在移动自组网(mobile ad hoc networks,简称MANET)中,节点的移动使无线链路经常发生断裂,从而导致路由无效.为了提高路由的稳定性,在分析单跳链路的t-时间维持概率的基础上,提出了一种基于路径t-时间维持概率的按需路由协议.该协议通过目的节点对路由请求的二次应答和中间节点对路由的反向优化来选择具有最大t-时间维持概率的路径,从而延长了路由的维持时间.仿真结果表明:与AODV(ad hoc on-demand distance vector)和DSR(dynamic source ro     

多场景的MPTCP协议性能分析研究

利用多宿主设备的多个接口实现多路径传输、获取更多的网络吞吐量是因特网协议研究的热点。IETF所关注的MPTCP协议是当前比较成熟、关键的多路径传输协议。为了测试MPTCP在当前已部署的网络环境中的性能,分别在本地测试床、Internet环境测试场景和大规模多宿主系统NorNet测试床中对MPTCP多路径传输实际吞吐量性能进行了测试和分析,测试结果表明MPTCP相对TCP虽能获得吞吐量的提高,但在非相似带宽链路的场景中其性能仍然不完善,其路径管理和传输调度策略仍需要进一步改进。     

Linear time distributed construction of colored trees for disjoint multipath routing

Disjoint multipath routing (DMPR) is an effective strategy to achieve robustness in networks where data is forwarded along multiple link- or node-disjoint paths. DMPR poses significant challenges in terms of obtaining loop-free multiple (disjoint) paths and effectively forwarding data over the multiple paths, the latter being particularly significant in datagram networks. One approach to reduce the number of routing table entries for disjoint multipath forwarding is to construct two trees, namely red and blue, rooted at a destination node such that the paths from a source to the destination on the two trees are link/node-disjoint. This paper develops the first distributed algorithm for constructing the colored trees whose running time is linear in the number of links in the network. The paper also demonstrates the effectiveness of employing generalized low-point concept rather than traditional low-point concept in the DFS-tree to reduce the average path lengths on the colored trees.     

Distributed routing in packet-switching networks by counterpropagation network

Routing is a problem of considerable importance in a packet-switching network, because it allows both optimization of the transmission speeds available and minimization of the time required to deliver information. In classical centralized routing algorithms, each packet reaches its destination along the shortest path, although some network bandwidth is lost through overheads. By contrast, distributed routing algorithms usually limit the overloading of transmission links, but they cannot guarantee optimization of the paths between source and destination nodes on account of the mainly local vision they have of the problem. The aim of the authors is to reconcile the two advantages of classical routing strategies mentioned above through the use of neural networks. The approach proposed here is one in which the routing strategy guarantees the delivery of information along almost optimal paths, but distributes calculation to the various switching nodes. The article assesses the performance of this approach in terms of both routing paths and efficiency in bandwidth use, through comparison with classical approaches.