Load Balanced Congestion Adaptive Routing for Randomly Distributed Mobile Adhoc Networks

In mobile ad hoc networks, congestion occurs due to limited sources of the network, which leads to packet losses, bandwidth degradation and wastes time and energy on congestion recovery. Various techniques have been developed in attempt to minimize congestion in uniformly distributed networks. In this paper, a load balanced congestion adaptive routing algorithm has been proposed for randomly distributed networks. In the proposed algorithm two metrics: traffic load density and life time associated with a routing path, have been used to determine the congestion status and weakest node of the route. The route with low traffic load density and maximum life time is selected for packet transmission.     

Optimized D-RAN Aware Data Retrieval for 5G Information Centric Networks

The evolution of wireless network services has enabled consumers and intelligent devices to freely exchange information with each other. Mobile users frequently exchange popular contents, resulting in massive increase in the mobile traffic. The redundant mobile traffic can be reduced by archiving the frequently accessed data within a 5G core network or radio access network, and demands for the same content can be readily met without relying on remote servers. In this paper, we propose an eNB/gNB aware data retrieval algorithm along with Liveliness and Size based data Replacement algorithm to refine, rank, and cache the data items efficiently. Data items are selected based on their popularity and cached in D-RAN for efficient data replacement. We have also included a cost-optimized Radar-Based data Retrieval algorithm that helps to find the data nearness in the neighbouring eNBs. In our proposed technique, unique contents are maintained at each end of the cluster to aid in extending content diversity within the cluster. The experimental analysis shows that the proposed model achieves lower latency, lower congestion, and higher cache hit ratio in 5G networks.

     

WDM网络中基于负载平衡的动态波长路由算法

在WDM网络中，路由和波长分配（RWA）算法是一个焦点问题．当前的RWA算法多是考虑路径跳数或全网拥塞程度，并没有分析各个链路的具体情况．文中提出一种WDM网络中能实现负载平衡的路由算法——最大波长跳数比值（MWHR）算法。基本思想是：根据各备选路径的跳数和其经过的各链路上的可用波长数信息。计算该路径的优先选取权值，优先选取权值最大的路径．仿真表明，该算法在保证较低的阻塞率情况下，能有效的将业务负载均衡分布在网络中的所有链路上．     

最小化路径代价和流量均衡模型及算法

流量均衡是流量工程中为避免网络拥塞经常采用的路由优化目标,如何选择路径以使流量达到均衡分布是流量路由的研究热点和难点.为了最小化网络拥塞,该文在指出网络拥塞决定于流量路由时所选路径的拥塞特征后,建立了流量分布的最小化路径代价和模型.在流量路由选择路径时,提出基于瓶颈链路的最小代价路径路由算法.在实际的网络拓扑和流量矩阵数据基础上对所提模型及算法进行了实验验证,结果显示:在网络负载较大时最大链路利用率相对于已有模型可降低近20%.     

考虑负载均衡和用户体验的垂直切换算法

在超密集异构无线网络中,针对城区交通高峰期,大规模车载终端短时间聚集性移动引起的网络拥塞问题,该文提出一种考虑负载均衡和用户体验(LBUE)的垂直切换算法。首先,引入网络环境感知模型预测网络未来的拥塞程度,并提出一个融合自组织网络的网络架构,缓解网络拥塞。其次,定义业务适应度和负收益因子,并提出一种基于秩和比(RSR)的自适应切换判决算法,为用户筛选出当前环境下满意度最高的目标网络。实验结果表明,该算法能够有效降低终端接入网络的阻塞率和掉话率,实现网络间负载均衡并提升用户体验。     

减少核心网拥塞的边缘计算资源分配和卸载决策

随着互联网的发展,智能终端在实践中得到了应用,大量时间敏感的计算机应用在人们的生活中也被广泛使用,如p/虚拟现实、智能家居和汽车互联网等。网络流量的增加将逐渐增大核心网络的压力,管理延迟网络变得越来越困难。目前,云协作计算解决方案是拟议的模型边界,文中提出了一种新的算法来管理边缘云之间基本网络流量的分布和解密,以共享时间和分配来改善边缘处理流程的算法资源,遗传算法用于寻找最佳分解分辨率。实验结果表明,与基线相比,拟议的算法可以提高资源效率并减少云流量边缘,从而减少核心网络拥堵现象。     

Joint QoS-control and handover optimization in backhaul aware SDN-based LTE networks

Future cellular networks will be dense and require key traffic management technologies for fine-grained network control. The problem gets more complicated in the presence of different network segments with bottleneck links limiting the desired quality of service (QoS) delivery to the last mile user. In this work, we first design a framework for software-defined cellular networks and then propose new mechanisms for management of QoS and non-QoS users traffic considering both access and backhaul networks, jointly. The overall SDN-LTE system and related approaches are developed and tested using network simulator in different network environments. Especially, when the users are non-uniformly distributed, the results shows that compared to other approaches, the proposed load distribution algorithm enables at least 6% and 23% increase in the average QoS user downlink throughput and the aggregate throughput of 40% users with lowest throughput (edge users), respectively. Also, the proposed system efficiently achieves desired QoS and handles the network congestion without incurring significant overhead.

     

一种基于移动用户行为的回路融合社区发现算法

针对现有基于派系的重叠社区发现算法难以对移动社会化网络实施的问题,该文给出一种基于移动用户行为的回路融合社区发现算法。该算法首先通过分析移动用户行为构建移动社会化网络,利用k-EC(k-Elementary Circuit)简单回路发现算法寻找移动社会化网络的k阶回路作为社区核,并按照给定的规则对社区核进行融合,得到初步社区;然后通过计算移动用户行为的相关度将余下的离散节点加入到相应的初步社区,得到最终的社区;最后通过公开数据集和仿真数据集验证了该算法在移动社会化网络社区发现方面的可行性和有效性。     

Bandwidth-aware routing and admission control for efficient video streaming over MANETs

In this paper, we develop and evaluate an adaptive self-configurable routing framework that can deal with dynamic nature of mobile ad hoc networks and provides quality-of-service (QoS) guarantees for efficient video streaming. Proposed framework mainly consists of two major components. Firstly, it is a reactive bandwidth-aware node-disjoint multipath routing protocol which determines routes based on the specified bandwidth requirements of the requesting application. The second component of the framework is a session admission control (SAC) process that permits or denies a session to enter into the network based on the current availability of network bandwidth. We also propose methods to handle QoS violations caused by network mobility and congestion by keeping backup routes, performing local route recovery, avoiding routing through short-lived low quality links and periodic monitoring of the active transmission routes. To verify our proposed algorithms, the network with H.264/SVC encoded video traces which are generated from real-time video traffic is used for modeling the behaviour of the source nodes. It has been observed that reactively discovered and maintained routes on the basis of the most recent information about network topology and available resources can significantly improve the admission decision accuracy of SAC process, in turn improving the quality of received video traffic significantly.

     

Adaptive Congestion Prediction in Vehicular Ad-hoc Networks (VANET) Using Type-2 Fuzzy Model to Establish Reliable Routes

Urban areas are more prone to accidents and traffic congestions due to ever-increasing vehicles and poor traffic management. The increase in the emission of harmful gases is another important issue associated with vehicular traffic. Attaining a level of QOS is often challenging as it has to meet the eco-friendly factors along with reliable and safe transportation. Smart and accurate congestion management systems in VANET can significantly reduce the risk of accidents and health issues. To fulfil the requirements of QOS the congestion control methods should consider the properties such as fairness, decentralization, network characteristics, and application demands in VANET. We proposed an Adaptive Congestion Aware Routing Protocol (ACARP) for VANET using the dynamic artificial intelligence (AI) technique. The ACARP presents the adaptive congestion detection algorithm using the type-2 fuzzy logic AI technique. The fuzzy model detects the congestion around each vehicle using three fuzzy inputs viz. bandwidth occupancy, link quality, and moving speed. This is followed by inference model to estimate congestion probability for each vehicle. Finally, defuzzification determines status of congestion detection using the pre-defined threshold value for each vehicle. The status of congestion and its probability values were utilized to establish safe and reliable routes for data transmission. It also saves significant communication overhead and hence congestions in the network. The simulation results provide the evidence that the proposed protocol improves the QOS and assist in reduction of traffic congestions significantly.

     

基于加权队列的无线智能电网通信网采集数据流量调度算法

智能电网的关键技术之一是为电力数据采集提供一个高效、可靠、安全的双向通信系统。使用具有通信能力的先进电力计量设备(智能电表)组成无线mesh网络采集数据,存在应用层数据流量对网络通信性能的挑战,当大量数据流量突发时,与本地局域网关较近的智能电表将面临较大的通信压力,可能产生严重的数据拥塞。为此,该文基于多网关联合的思想,提出一个新的基于加权队列的流量调度算法以缓解拥塞。首先,对多网关联合网络进行分析,确定影响网络性能的主要因素。其次采用队列加权的方法,提出新的流量调度算法。最后进行网络仿真,相对其它算法,该文所提算法能够极大缓解数据突发时刻的系统拥塞,有效地降低时延,同时在系统各网关吞吐量之间取得良好的平衡,能够提高采集网络的通信性能。     

基于智能网络的租户服务质量保证技术

在多租户虚拟网络环境中,用户对于网络服务的多样性以及性能的稳定性需求并不会随着网络架构和运营模式的升级而削弱,用户需求之间的差异性和动态性对于不同切片间资源的分配和调度效率提出了新的挑战。针对多租户虚拟网络的特殊环境,首先提出了QVR(QoS-Virtual Routing)流量调度算法,同时将用户流量调度与网络虚拟资源分配看做一个联合优化问题,提出了面向多租户的流量调度算法以及适用于共享链路的动态带宽分配算法。该算法能够释放更多的物理网络资源,明显降低了租户网络的延时和拥塞。     

基于链接相似性聚类的重叠社区识别

社区结构是社会网络最普遍和重要的拓扑属性之一,提出一种基于链接相似性聚类的重叠社区识别算法.该算法首先根据相邻链接的度分布状态,提出链接间的相似性度量方法;其次以链接相似性矩阵为输入,以链接社区的最优划分为目标,建立链接局部相似性聚类算法,实现了重叠社区的有效识别;然后对链接社区进行优化,解决了可能出现的过度重叠及孤立社区问题;最后在真实网络及人工合成网络上的实验验证了算法的高效性.     

Difficulties in simulating the Internet

Simulating how the global Internet behaves is an immensely challenging undertaking because of the network's great heterogeneity and rapid change. The heterogeneity ranges from the individual links that carry the network's traffic, to the protocols that interoperate over the links, the “mix” of different applications used at a site, and the levels of congestion seen on different links. We discuss two key strategies for developing meaningful simulations in the face of these difficulties: searching for invariants and judiciously exploring the simulation parameter space. We finish with a look at a collaborative effort within the research community to develop a common network simulator     

Impact of Secondary User Block on the TCP Throughput in Cognitive Radio Sensor Networks

The cognitive radio sensor network (CRSN) has emerged as a promising solution to overcome spectrum under-utilization and spectrum scarcity problems in a resource-constrained wireless sensor network. In CRSN, TCP has to cope with a new type of packet loss due to the primary users arrival, known as secondary user blocking loss (SBL), otherwise It leads to significant TCP throughput degradation. In this paper, two main contributions are provided on the modeling of SBL and throughput evaluation of transport layer protocol for CRSN. First, it is identified two main factors of SBL and the probability of them is modeled by a discrete-time Markov chain. Second, a new congestion control algorithm is proposed to distinguish between actual congestion from the wrong congestion due to the SBL by considering the dynamic nature of CRSN. The obtained results through proposed model are verified using the COGNS framework based on NS2, which is a simulation framework for cognitive radio sensor networks. The proposed algorithm is compared with some of the well-known transport protocol TFRC-CR, OHTP and TCP Reno. The results confirm that our proposed algorithm is the best among them.

     

Dynamic link sleeping reconfigurations for green traffic engineering

The high volume of energy consumption has become a great concern to the Internet community because of high energy waste on redundant network devices. One promising scheme for energy savings is to reconfigure network elements to sleep mode when traffic demand is low. However, due to the nature of today's traditional IP routing protocols, network reconfiguration is generally deemed to be harmful because of routing table reconvergence. To make these sleeping network elements, such as links, robust to traffic disruption, we propose a novel online scheme called designate to sleep algorithm that aims to remove network links without causing traffic disruption during energy‐saving periods. Considering the nature of diurnal traffic, there could be traffic surge in the network because of reduced network capacity. We therefore propose a complementary scheme called dynamic wake‐up algorithm that intelligently wakes up minimum number of sleeping links needed to control such dynamicity. This is contrary to the normal paradigm of either reverting to full topology and sacrificing energy savings or employing on‐the‐fly link weight manipulation. Using the real topologies of GEANT and Abilene networks respectively, we show that the proposed schemes can save a substantial amount of energy without affecting network performance.     

Stable routing algorithm for mobile ad hoc networks using mobile agent

Wireless ad hoc networks are growing important because of their mobility, versatility, and ability to work with fewer infrastructures. The mobile ad hoc network is an autonomous system consisting of mobile nodes connected with wireless links. Establishing a path between two nodes is a complex task in wireless networks. It is still more complex in the wireless mobile ad hoc network because every node is no longer as an end node and an intermediate node. In this paper, it focuses on design of connectionless routing protocol for the wireless ad hoc networks based on the mobile agent concept. The proposed model tries to discover the best path taking into consideration some concerns like bandwidth, reliability, and congestion of the link. The proposed model has been simulated and tested under various wireless ad hoc network environments with the help of a different number of nodes. The results demonstrate that the proposed model is more feasible for providing reliable paths between the source and destination with the minimum control message packets over the network. It has delivered more number of packets to the destination over the network. Copyright © 2012 John Wiley & Sons, Ltd.     

Design and Performance Analysis of a Proxy-Based Indirect Routing Scheme in Ad Hoc Wireless Networks

The majority of existing ad hoc network routing protocols has a tendency to use the shortest single path from a source to a destination. However, in constantly changing topologies such as those in mobile ad hoc wireless networks, the shortest single path is not only unreliable for reachability but also unsuitable for traffic load equilibrium. In order to improve routing performance and make optimum use of the limited resources, the congestion must first be relieved as much as possible and the routing path be made available at all times. In this paper, we propose a novel scheme, called the Applicative Indirect Routing (AIR), to control network traffic congestion and refine route availability by coping with unreliable links quickly. The proposed scheme, acting as a proactive routing protocol, utilizes additional information about the neighbors shared by the sender and the receiver to find an alternative for the original path with unreliable links. The additional bandwidth usage in AIR to obtain the information about shared neighbors (defined as proxy candidates) is so minimal that the bandwidth availability for user data traffic is not significantly affected. Extensive simulation experiments show that compared with a conventional proactive protocol, namely Destination-Sequenced Distance Vector (DSDV), the AIR scheme leads to a much improved system performance in terms of packet delivery ratio, average end-to-end packet delay, and network reliability. We further show that, in terms of packet delivery ratio, AIR is also a competitive protocol compared with such reactive protocols as Ad hoc On Demand Distance Vector (AODV) and Dynamic Source Routing (DSR).     

Smart Backhauling for 5G Heterogeneous Network with Millimeter Wave Backhaul Links to Perform Switching Off,Interference Management and Backhaul Routing

Developments made in the fifth generation (5G) and the cellular networks have greatly influenced the lifestyle of the wireless users. Increased demand on higher data rates has also increased the network traffic. In the viewpoint of cellular networks, several Small Cells (SCs) are combined together with the help of microwave communications and millimeter wave communication models, in order to support the heterogeneous environments. In this paper, we have proposed a hybrid communication framework which can efficiently support the interference management, routings in backhaul links and the joint issue during on/off status of the mobile using 5G mmWave backhaul links. A novel cache-enabled technology is designed to develop backhaul links using heuristic search models. Along with that, an effective data access framework is also formulated using distance based cluster head selection that resolves the interference issues. Without modifying the content of the mobile users, the services are offered to the uses associated with backhaul links. Since a fast iterative model is developed, the throughput rate and the energy savings are maximized. A simulation analysis is carried out with a static number of mobile nodes which has proved the efficiency of the proposed framework.