大规模无线通信网络移动边缘计算和缓存研究

面向未来6G移动通信的大规模网络移动边缘计算与缓存技术,首先,介绍了大规模无线网络下移动边缘计算和缓存的架构与原理,并阐释了移动边缘计算和缓存技术在大规模无线网络中的必要性和普适性.接着,从计算卸载、边缘缓存、多维资源分配、用户关联和隐私保护这5个关键问题出发,综述和分析了移动边缘计算和缓存赋能大规模无线网络时会引入的...     

Proactive content caching by exploiting transfer learning for mobile edge computing

To address the vast multimedia traffic volume and requirements of user quality of experience in the next‐generation mobile communication system (5G), it is imperative to develop efficient content caching strategy at mobile network edges, which is deemed as a key technique for 5G. Recent advances in edge/cloud computing and machine learning facilitate efficient content caching for 5G, where mobile edge computing can be exploited to reduce service latency by equipping computation and storage capacity at the edge network. In this paper, we propose a proactive caching mechanism named learning‐based cooperative caching (LECC) strategy based on mobile edge computing architecture to reduce transmission cost while improving user quality of experience for future mobile networks. In LECC, we exploit a transfer learning‐based approach for estimating content popularity and then formulate the proactive caching optimization model. As the optimization problem is NP‐hard, we resort to a greedy algorithm for solving the cache content placement problem. Performance evaluation reveals that LECC can apparently improve content cache hit rate and decrease content delivery latency and transmission cost in comparison with known existing caching strategies.     

OverMesh: network-centric computing [Accepted from Open Call]

The communications industry significantly lags behind the personal computing industry in terms of empowering the end user to innovate, as fundamental architectural shifts have yet to occur to push intelligence to the network edge. The decentralization of the telecommunication system to the edge of today's hierarchically formed networks is inevitable with the emergence of key wireless technologies and the proliferation of mobile computing devices and more prevailing usage models. This article envisions a decentralized communication system formed of wireless mesh networks and a highly virtualized, converged computing and communications node-based architecture with emergent management capabilities. We propose to embed the user inside the network to freely associate services and resources such as computing, storage, and bandwidth to rapidly advance network innovation - network-centric computing. This article proposes a novel direction and vision for network-centric computing, expands upon our research, and presents the OverMesh platform from which we have begun work to instantiate this vision. Finally, we expect this new envisioned network to coexist with today's Internet infrastructure and enable a new generation of applications and usage models     

Cache‐at‐relay: energy‐efficient content placement for next‐generation wireless relays

Uploading and downloading content have recently become one of the major reasons for the growth of Internet traffic volume. With the increasing popularity of social networking tools and their video upload/download applications, as well as the connectivity enhancements in wireless networks, it has become a second nature for mobile users to access on‐demand content on‐the‐go. Urban hot spots, usually implemented via wireless relays, answer the bandwidth need of those users. On the other hand, the same popular contents are usually acquired by a large number of users at different times, and fetching those from the initial content source each and every time makes inefficient use of network resources. In‐network caching provides a solution to this problem by bringing contents closer to the users. Although in‐network caching has been previously studied from latency and transport energy minimization perspectives, energy‐efficient schemes to prolong user equipment lifetime have not been considered. To address this problem, we propose the cache‐at‐relay (CAR) scheme, which utilizes wireless relays for in‐network caching of popular contents with content access and caching energy minimization objectives. CAR consists of three integer linear programming models, namely, select relay, place content, and place relay, which respectively solve content access energy minimization, joint minimization of content access and caching energy, and joint minimization of content access energy and relay deployment cost problems. We have shown that place relay significantly minimizes the content access energy consumption of user equipments, while place content provides a compromise between the content access and the caching energy budgets of the network. Copyright © 2015 John Wiley & Sons, Ltd.     

内容流行分布动态性对基站端缓存性能的影响

为了满足移动数据的爆炸性增长,在无线边缘部署缓存已经成为下一代移动通信的研究热点之一。业务模型与实际相符的程度直接决定了无线缓存性能评估的准确性,然而目前几乎所有关于无线缓存的文献所采用的文件请求模型并未考虑内容流行分布的动态变化。最近已有文献考虑时变流行分布,但是均采用了被动缓存策略,而主动缓存策略对无线缓存十分重要。本文分别基于一个能够描述内容流行度动态变化的文件请求模型——散粒噪声模型、和现有文献中广泛采用的独立参考模型,分析了采用被动和基于预测的主动基站缓存策略时内容流行分布动态变化对命中率和无线网络吞吐量的影响。仿真结果表明,采用散粒噪声模型对评估无线缓存系统吞吐量的影响很大,特别是当网络中干扰较小时;另外,已有文献基于被动缓存策略得到的结论并不适于主动缓存策略。      

Design and Performance Studies of an Adaptive Scheme for Serving Dynamic Web Content in a Mobile Computing Environment

Currently, people gain easy access to an increasingly diverse range of mobile devices such as personal digital assistants (PDAs), smart phones, and handheld computers. As dynamic content has become dominant on the fast-growing World Wide Web (C. Yuan et al., 2003), it is necessary to provide effective ways for the users to access such prevalent Web content in a mobile computing environment. During a course of browsing dynamic content on mobile devices, the requested content is first dynamically generated by remote Web server, then transmitted over a wireless network, and, finally, adapted for display' on small screens. This leads to considerable latency and processing load on mobile devices. By integrating a novel Web content adaptation algorithm and an enhanced caching strategy, we propose an adaptive scheme called MobiDNA for serving dynamic content in a mobile computing environment. To validate the feasibility and effectiveness of the proposed MobiDNA system, we construct an experimental testbed to investigate its performance. Experimental results demonstrate that this scheme can effectively improve mobile dynamic content browsing, by improving Web content readability on small displays, decreasing mobile browsing latency, and reducing wireless bandwidth consumption     

Intrusion Detection Techniques for Mobile Wireless Networks

The rapid proliferation of wireless networks and mobile computing applications has changed the landscape of network security. The traditional way of protecting networks with firewalls and encryption software is no longer sufficient and effective. We need to search for new architecture and mechanisms to protect the wireless networks and mobile computing application. In this paper, we examine the vulnerabilities of wireless networks and argue that we must include intrusion detection in the security architecture for mobile computing environment. We have developed such an architecture and evaluated a key mechanism in this architecture, anomaly detection for mobile ad-hoc network, through simulation experiments.     

Measurement and analysis of online gaming services on mobile WiMAX networks

Online games have been played mainly in desktop computers over wired networks because of high speed and intensive computation requirements. The advances in mobile devices and ever increasing wireless link bandwidth motivate us to study whether players can enjoy online gaming over broadband wireless networks such as mobile Worldwide Inter‐operability for Microwave Access (WiMAX). In this paper, we carry out comprehensive measurements of the World of Warcraft (WoW) over the mobile WiMAX in Seoul, Korea, and analyze the network performance focusing on two aspects: (1) network layer dynamics such as round trip time, jitter, and packet loss and (2) WiMAX link layer statistics such as the radio signal strength, handovers, and piggyback mechanism. From the empirical data, we set up performance models and evaluate the performance of WoW over WiMAX. We also discuss how to improve the service quality of online gaming over WiMAX.Copyright © 2013 John Wiley & Sons, Ltd.     

FSR和Lanmar结合应用于移动Ad hoc网

移动Adhoc网在军事和民用方面具有广阔的应用前景，是近几年网络研究的热点问题。主要介绍了Lanmar路由协议和FSR路由协议如何有效配合应用于移动Adhoc。     

一种基于WTLS的轻型移动VPN方案

各种传统的远程访问VPN方案(包括IPSec-VPN和SSL-VPN)都只是为固网环境下外出企业员工的"游牧访问"而设计的,它不适合于未来的移动无线网络场景.本文针对移动无线场景中特有的无线终端计算能力和网络带宽限制等问题,提出了一种基于WTLS安全协议的轻型移动VPN方案.该移动VPN方案支持移动节点在不同无线接入网络之间的自由切换,允许外出企业员工在任何时间、任何地点、使用最佳的无线接入网络连接到企业网络并安全地访问企业内部资源.     

Dynamic process location management in 5G

5G, as the next generation of wireless networks, promises very high throughput and low latency to mobile users that calls for a substantial innovation in computing management platforms to attend QoS metrics. Thanks to emerging technologies such as software‐defined networking (SDN)/network function virtualization (NFV), many features are available in 5G design to detect and control two types of latency caused by computation and communication. In this paper, taking features of caching mechanisms and SDN into the account, a platform is proposed to minimize latency in 5G via caching big flows intelligently and avoiding bottlenecks that may cause by virtualized computing components. First, the pioneering idea of compromising between the cloud radio access network (CRAN) and mobile edge computing (MEC)/information‐centric network (ICN) via dynamic processing location management platform is investigated. Accordingly, a mathematical optimization problem to minimize the average latency is formulated. Due to the problem complexity, a heuristic algorithm is proposed to treat the latency via dynamic orchestration of processing functionalities. Through numerical results, the performance of the proposed algorithm is analyzed, and the simulations corroborate our analytical results and illustrate the superior performance of the proposed algorithm with acceptable optimality gap.     

基于边缘计算的高效视频内容分发关键技术与挑战

近年来移动互联网、工业互联网的快速发展,引发媒体计算与服务的一个新的趋势:以视频为代表的多媒体数据的产生、处理和分发越来越多地趋向网络边缘。复杂应用环境下,用户行为、系统资源的不确定性成为网络视频服务面临的重大挑战。如何引入人工智能与机器学习的方法,利用网络边缘的计算、存储和网络资源实现视频内容分发随需而动,从而支撑更低延迟、更高带宽需求的网络视频服务,逐渐成为新的研究和应用热点。该综述分析了基于边缘计算的视频分发所面临的挑战,提出了通过边缘计算的网络、存储和计算能力来进行视频内容分发的框架,并在此框架下给出了边缘缓存及替换、边缘内容预取、边缘内容收集和边缘计算迁移等视频分发的优化策略设计。     

A Neural Network-Based Connectivity Management for Mobile Computing Environment

The mobile computing environment experiences wireless problems and suffers from limited bandwidth, which leads to frequent disconnections. This has posed a challenge in maintaining user-to-user connectivity in the mobile computing environment. In this paper, we propose a neural network (NN) based connectivity management for mobile computing environment to maintain the mobile user-to-user connectivity throughout the transaction. Here the connectivity management maintains the status information of mobile hosts at the base station to handle frequent disconnection of mobile hosts (MHs), which occur because of hand-offs and interruptions. The disconnection of an MH because of wireless problems is called interruption, and the disconnection due to MH crossing the cell boundary is called hand-off. The neural networks are trained with respect to the status information to provide an intelligent decision for the connectivity management. The simulation results demonstrate that the proposed technique performs well in terms of percentage acceptance of disconnections and resource utilization (bandwidth and buffer) for the volatile mobile computing environment. It is also observed that the intelligent decision by neural network has improved the performance of the system.     

Performance Evaluation of Polling Protocols for Data Transmission on Wireless Communication Networks

The growing interest in mobile computing and communication devices leads to the necessity of wireless broadband network. Data transmission over such networks requires suitable error control schemes to guarantee high data reliability as well as efficient bandwidth utilization.In this paper we propose an accurate yet simple analytical approach to evaluate the performance of wireless networks using gated and exhaustive polling protocols combined with the Stop and Wait (SW) or Go Back N (GBN) ARQ schemes [Bertsekas and Gallager, 2]. Moreover, simulation results concerning the performance of polling protocols combined with the Selective Repeat (SR) ARQ scheme are also shown for comparison purposes.Protocol performance is estimated under very general assumptions, such as: AWGN or fading channels, arbitrary value of the round trip delay and arbitrary distribution of the traffic load (i.e., both symmetric or asymmetric system have been considered).     

基于DPI的内容缓存技术及应用

随着3G时代的来临,越来越多的用户通过手机、上网卡访问互联网。为提升3G用户上网体验,本文提出基于DPI(DeepPacketInspection,深度数据包检测)的内容缓存技术,对该技术的技术原理、系统架构、系统的部署方式进行了研究。应用该技术,通过在城域网上建立缓存节点,可有效缓解城域网出口带宽压力,节省网间结算,提升用户上网体验。     

Cooperative content delivery exploiting multiple wireless interfaces: methods,new technological developments,open research issues and a case study

In this tutorial paper, we discuss and compare cooperative content delivery (CCD) techniques that exploit multiple wireless interfaces available on mobile devices to efficiently satisfy the already massive and rapidly growing user demand for content. The discussed CCD techniques include simultaneous use of wireless interfaces, opportunistic use of wireless interfaces, and aggregate use of wireless interfaces. We provide a taxonomy of different ways in which multiple wireless interfaces are exploited for CCD, and also discuss the real measurement studies that evaluate the content delivery performance of different wireless interfaces in terms of energy consumption and throughput. We describe several challenges related to the design of CCD methods using multiple interfaces, and also explain how new technological developments can help in accelerating the performance of such CCD methods. The new technological developments discussed in this paper include wireless interface aggregation, network caching, and the use of crowdsourcing. We provide a case study for selection of devices in a group for CCD using multiple interfaces. We consider this case study based on the observation that in general different CCD users can have different link qualities in terms of transmit/receive performance, and selection of users with good link qualities for CCD can accelerate the content delivery performance of wireless networks. Finally, we discuss some open research issues relating to CCD using multiple interfaces.     

Cooperative Caching in Wireless Multimedia Sensor Networks

The recent advances in miniaturization and the creation of low-power circuits, combined with small-sized batteries have made the development of wireless sensor networks a working reality. Lately, the production of cheap complementary metal-oxide semiconductor cameras and microphones, which are able to capture rich multimedia content, gave birth to what is called Wireless Multimedia Sensor Networks (WMSNs). WMSNs will boost the capabilities of current wireless sensor networks, and will fuel several novel applications, like multimedia surveillance sensor networks. WMSNs introduce several new research challenges, mainly related to mechanisms to deliver application-level Quality-of-Service (e.g., latency minimization). To address this goal in an environment with extreme resource constraints, with variable channel capacity and with requirements for multimedia in-network processing, the caching of multimedia data, exploiting the cooperation among sensor nodes is vital. This article presents a cooperative caching solution particularly suitable for WMSNs. The proposed caching solution exploits sensor nodes which reside in “positions” of the network that allow them to forward packets or communicate decisions within short latency. These so-called “mediator” nodes are selected dynamically, so as to avoid the creation of hot-spots in the communication and the depletion of their energy. The mediators are not more powerful than the rest of the nodes, but they have some special role in implementing the cooperation among the sensors. The proposed cooperative caching protocol includes components for locating cached data as well as for implementing data purging out of the sensor caches. The proposed solution is evaluated extensively in an advanced simulation environment, and it is compared to the state-of-the-art cooperative caching algorithm for mobile ad hoc networks. The results confirm that the proposed caching mechanism prevails over its competitor.     

Challenges for nomadic computing: Mobility management and wireless communications

In this paper, we present several challenges and innovative approaches to support nomadic computing. The nomadic computing environment is characterized by mobile users that may be connected to the network via wired or wireless means, many of whom will maintain only intermittent connectivity with the network. Furthermore, those accessing the network via wireless links will contend with limitations of the wireless media. We consider three general techniques for addressing these challenges: (1) asymmetric design of applications and protocols, (2) the use of network-based proxies which perform complex functions on behalf of mobile users, and (3) the use of pre-fetching and caching of critical data. We examine how these techniques have been applied to several systems, and present results in an attempt to quantify their relative effectiveness.     

多接入移动边缘计算技术在移动网络的部署实践与思考

多接入移动边缘计算(MEC)技术是当前兴起的一项新技术。通过把计算、存储、带宽和应用等资源放在网络的边缘侧,以减小传输延迟和带宽消耗。MEC可以广泛应用于运营商的4G/5G等移动网络以及Wi-Fi无线网络,并将会成为未来工业自动化和信息化应用的新一代解决方案。本文介绍了多接入移动边缘计算技术如何与4G/5G移动网络结合并在行业场景中的实际尝试和探索,并对主要研究进展和需解决的关键问题进行了介绍。     

CDN边缘节点部署位置下沉的研究

CDN的出现,把流量推到网络的边缘,缓解主干网络的拥堵。当前CDN运营商的主要部署节点是在IDC机房,在通信运营商看来,IDC到最终用户还隔着CMNET,核心网与传送网。随着手机、平板等无线设备的普及,给核心网带宽压力越来越大。将CDN边缘节点下层到核心网中,对缓解核心网的网络压力,降低网络时延有着巨大的作用。本文对CDN边缘节点下沉的可行型及方案进行了分析,并特别针对当前研究比较少的CDN边缘计算节点进行了分析,由于缓存系统与CDN已渐成融合的趋势,本文将缓存系统的节点视为CDN边缘节点。