An integrated testbed for wireless multimedia computing

A testbed has been constructed to evaluate node architectures that support multimedia applications and services across a wireless network. Using this testbed, a low bitrate subband video compression algorithm has been prototyped in a field programmable gate array (FPGA) and evaluated for video networking across bandwidth-limited RF channels. A radio interface has been prototyped in an FPGA and a common applications programming interface (API) has been developed to allow experimentation with multiple radios. This testbed has been used to evaluate node performance under two different wireless applications: 1) simultaneous video and data networking (VTALK) and 2) TCP/IP utilities such as FTP and telnet. Based on this evaluation, the design of a battery-operated high throughput wireless multimedia node is presented.     

Network management research in ATDNet

The Advanced Technology Demonstration Network (ATDNet) is a major testbed facility established by DARPA and other U.S. government agencies to conduct network and applications research on the next generation of high speed ATM/SONET networks. This article presents the approaches and results of our work in network management on ATDNet. The research addresses different aspects of next-generation systems design, including integrated network management of different technology layers, multitier and multiprotocol architectures, robust distributed computing platforms, and object-oriented technologies. To address these challenges in a practical manner, the authors describe their implementation of a prototype software system developed on a distributed computing platform, discuss how this research addresses the current and evolving needs of ATDNet, and present possible future research directions     

On optimal design of multitier wireless cellular systems

We present a general cell-design methodology for the optimal design of a multitier wireless cellular network. Multitier networks are useful when there are a multitude of traffic types with drastically different parameters and/or different requirements, such as different mobility parameters or quality-of-service requirements. In such situations, it may be cost-effective to build a multitude of cellular infrastructures, each serving a particular traffic type. The network resources (e.g., the radio channels) are then partitioned among the multitude of tiers. In general terms, we are interested in quantifying the cost reduction due to the multitier network design, as opposed to a single-tier network. Our study is motivated by the expected proliferation of personal communication services, which will serve different mobility platforms and support multimedia applications through a newly deployed infrastructure based on the multitier approach     

Design and Implementation of an Educational Testbed for Experiencing With Industrial Communication Networks

This paper presents the design and implementation of an educational testbed developed for a course on industrial communication networks at the Engineering Faculty, University of Catania. The aim is to realize a platform capable of emulating various network configurations, thus enabling students to find out by themselves through practical experiments how different design choices, parameter settings, network configurations, and algorithms impact on the overall network performance. The testbed comprises a number of basic components (hosts, routers, and access points) implemented on nodes equipped with operating systems and open source software, which together make up a modular system. Each router can be loaded with data flows and monitored over preestablished time windows so as to evaluate its performance in a wide range of operating conditions. The wireless part makes it possible to configure environments with different levels of noise and bandwidth utilization so as to emulate a broad spectrum of real operating environments. The testbed can be used via remote access through a web interface that not only allows the operating conditions to be configured but also permits real-time monitoring. Students can configure the testbed on the basis of the network they are studying and can measure its performance for evaluation purposes.     

Architectures for Heterogeneous Multi-Tier Networks

Next-generation wireless computing platforms will contain flexiblecommunications capabilites. At Rice University,the Rice Everywhere NEtwork (RENÉ) project is investigating a multi-standard, multi-tierintegration of W-CDMA cellular systems, high speed wireless LANs, and home wireless networks.There are many challenges in mapping these advanced communicationalgorithms to real-time hardware computing platforms.In this paper, we present current work on the developmentof a reconfigurable baseband physical layer containing DSP processorsand FPGA accelerators. Our goal is the design of amulti-tier network interface card (mNIC) which is capableof exploiting efficient, low-power reconfiguration.     

The Emergence of Industrial Control Networks for Manufacturing Control, Diagnostics, and Safety Data

The most notable trend in manufacturing over the past five years is probably the move towards networks at all levels. At lower levels in the factory infrastructure, networks provide higher reliability, visibility, and diagnosability, and enable capabilities such as distributed control, diagnostics, safety, and device interoperability. At higher levels, networks can leverage internet services to enable factory-wide automated scheduling, control, and diagnostics; improve data storage and visibility; and open the door to e-manufacturing. This paper explores current trends in the use of networks for distributed, multilevel control, diagnostics, and safety. Network performance characteristics such as delay, delay variability, and determinism are evaluated in the context of networked control applications. This paper also discusses future networking trends in each of these categories and describes the actual application of all three categories of networks on a reconfigurable factory testbed (RFT) at the University of Michigan. Control, diagnostics, and safety systems are all enabled in the RFT utilizing multitier networked technology including DeviceNet, PROFIBUS, OPC, wired and wireless Ethernet, and SafetyBUS p. This paper concludes with a discussion of trends in industrial networking, including the move to wireless for all categories, and the issues that must be addressed to realize these trends     

一种无线Mesh实验网络的构建

无线Mesh网络作为一种新型组网方式,已成为当前网络技术研究的热点。本文提出一种Mesh网络研究的实验测试平台,给出了整体的实现方案,并就实现细节做了详细的介绍。本方案主要采用当前流行的WLAN技术,结合PC机的灵活性和Linux操作系统的丰富功能和稳定性,实现Mesh网络的结构。经测试验证,网络性能稳定,功能良好。     

Dynamic bandwidth management and adaptive applications for avariable bandwidth wireless environment

This article describes an approach for providing dynamic quality of service (QoS) support in a variable bandwidth network, which may include wireless links and mobile nodes. The dynamic QoS approach centers on the notion of providing QoS support at some point within a range requested by applications. To utilize dynamic QoS, applications must be capable of adapting to the level of QoS provided by the network, which may vary during the course of a connection. To demonstrate and evaluate the dynamic QoS concept, we have implemented a new protocol called dynamic resource reservation protocol (dRSVP) and a new QoS application program interface (API). The paper describes this new protocol and API and also discusses our experience with adaptive streaming video and audio applications that work with the new protocol in a testbed network, including wireless local area network connectivity and wireless link connectivity emulated over the wired Ethernet. Qualitative and quantitative assessments of the dynamic RSVP protocol are provided     

Architecture and Experimental Framework for Supporting QoS in Wireless Networks Using Differentiated Services

This paper describes the design and implementation of an enhanced Differentiated Services (Diffserv) architectural framework for providing Quality of Service (QoS) in wireless networks. The Diffserv architecture has been recently proposed to complement the Integrated Services (Intserv) model for providing QoS in the wired Internet. The paper studies whether Diffserv, as defined for wired networks, is suitable for wireless networks. The proposed wireless Diffserv framework takes into consideration several factors, including signaling requirements, mobility, losses, lower wireless bandwidth and battery power constraints. It identifies the need for supporting signaling and mobility in wireless networks. The framework and mechanisms have been implemented in the wireless testbed at Washington State University. Experimental results from this testbed show the validity of the proposed Diffserv model and also provide performance analyses. The framework is also designed to be extensible so that other researchers may use our implementation as a foundation for implementing other wireless network algorithms and mechanisms.     

一个并行无线传感器网络模拟框架

提出了一个面向应用型和面向协议型相结合的并行无线传感器网络模拟系统（WSNSim）框架。设计目标是系统具有广泛的应用场合，被模拟网络规模具有很好的可扩展性，并且系统运行具有较高的效率。采用此框架开发的软件系统将为不同的传感器网络应用提供试验平台，同时支持传感器网络各层协议的开发研究及性能评价。     

Survey on SDN-based network testbeds

The network testbed based on software defined networking (referred as SDN testbed) has attracted extensive attention in the academic and industrial circles in recent years,and there have been many valuable cases of system/platform construction.Therefore,an overview of the SDN testbed was intended to conduct in the global scope.Firstly,the advantages of the SDN testbed and the basic design principles of the large-scale SDN testbed was explored comparing with the traditional network testbed.Secondly,in-depth analysis of existing SDN testbed projects was provided from the aspects of the project objectives and progress,the key technologies,network deployment,and featured applications.Finally,the challenges faced in this field were described in terms of network slicing,light and wireless convergence,security,and reliability.Future research directions are also suggested.     

Experiences from the design, deployment, and usage of the UCSB MeshNet testbed

In this article we report on our effort and experience in designing, deploying, and using our 30-node wireless mesh testbed, the University of California at Santa Barbara (UCSB) MeshNet. Compared to simulation, the construction and utilization of a wireless mesh testbed poses many new challenges. We discuss the challenges with distributed testbed management, nonintrusive and distributed monitoring, and node status visualization. These are vital components in a sustainable wireless mesh testbed, but at the same time nontrivial to design and. realize. As a case study, we present the UCSB MeshNet architecture, including its management, monitoring, and visualization systems. We share our lessons learned from this effort and believe that they are valuable to other researchers who develop experimental wireless mesh networks.     

Design considerations for a multihop wireless network testbed

Limited fidelity of simulators has prompted researchers to build wireless network testbeds for realistic testing. Unlike simulators, which have broad applicability, most of these testbeds are tailored to specific projects and cannot be used by a wider research community. Recognizing the growing importance of testbeds, this article is one of the first attempts to identify a comprehensive set of requirements for a general-purpose multihop wireless network testbed and the challenges therein. The issues range from initial testbed deployment and routine management to individual experimental configuration and data collection. We survey state-of-the-art wireless testbeds and highlight their salient features. The article is intended to provide an initial reference for researchers, application developers, and administrators dealing with various aspects of wireless network testbeds.     

无线Mesh网络试验床的构建与应用

本文首先叙述了无线Mesh网络国内外研究和发展动态;接着描述了上海交通大学SJTU-Mesh网络试验床的体系结构,包括系统架构、硬件平台和软件结构;然后介绍了试验床的部署与应用情况;最后给出了对未来工作的展望.     

A Study of the Simulation Model in WCDMA Systems

Ｉｎｔｈｉｓｄｉｓｓｅｒｔａｔｉｏｎ ,ｗｅｅｓｔａｂｌｉｓｈａｎｅｎｄ ｔｏ ｅｎｄｓｉｍｕｌａｔｉｏｎｍｏｄｅｌｆｏｒｔｈｅｐｅｒｆｏｒｍａｎｃｅｅｖａｌｕａｔｉｏｎｏｆＷＣＤＭＡ/ＡＴＭ ｂａｓｅｄｔｈｉｒｄ ｇｅｎｅｒａｔｉｏｎｃｅｌｌｕｌａｒｓｙｓ ｔｅｍｓｗｈｅｒｅｗｅｔａｋｅｉｎｔｏａｃｃｏｕｎｔｔｈｅｑｕａｌｉｔｙｏｆｓｅｒ ｖｉｃｅｓｉｎｔｈｅｉｎｔｅｇｒａｔｅｄｖｏｉｃｅ ｄａｔａｅｎｖｉｒｏｎｍｅｎｔ.Ｔｈｉｓｄｉｓｓｅｒｔａｔｉｏｎａｉｍｓｔｏｐｒｏｖｉｄｅａｆｒａｍｅｗｏｒｋｆｏ…     

3GPP LTE: The Future of Mobile Broadband

The mobile broadband technologies are reaching a commonality in the air interface and networking architecture; they are being converged to an IP-based network architecture with Orthogonal Frequency Division Multiple Access (OFDMA) based air interface technology. From technical perspective, fundamental goal of mobile broadband is to offer higher data rates with reduced latency. The third Generation Partnership Project (3GPP) presents the Long-Term Evolution (LTE) project in order to accommodate increasing mobile data usage and new multimedia applications. In the near future, with the recent progress made by technical specifications and vendor technology demonstrations LTE will emerge as successor to cellular systems as a broadband wireless solution. This paper provides an overview of 3GPP LTE including its history, features, technology, architecture and future. The technology components include OFDMA air-interface, Multiple-Input and Multiple-Output (MIMO) antenna technology and higher order modulation. The architecture includes Evolved Packet Core (EPC) and Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) components. This paper will concentrate to describe the main functions of the most important network elements. Also, the aim of this paper is to present the future potential of LTE which will make it an inevitable choice for wireless network operators around the globe.     

实用无线网状网的设计、构建与测试

无线网状网是一种能够广泛应用于多种场合的无线网络结构。论文首先介绍丁无线网状网的特性,描述了在实际应用环境中,对无线网状网节点的设计和构建需求,并以此为依托给出了设计办案然后介绍了SJTU—MESH试验床的部署与碰用情况,以及在试验床上进行的对无线网状网系统的定量测试及其结果,最后给出了结论和对未来工作的展望。     

DRAND: Distributed Randomized TDMA Scheduling for Wireless Ad Hoc Networks

This paper presents a distributed implementation of RAND, a randomized time slot scheduling algorithm, called DRAND. DRAND runs in O(delta ) time and message complexity where delta is the maximum size of a two-hop neighborhood in a wireless network while message complexity remains O(delta ), assuming that message delays can be bounded by an unknown constant. DRAND is the first fully distributed version of RAND. The algorithm is suitable for a wireless network where most nodes do not move, such as wireless mesh networks and wireless sensor networks. We implement the algorithm in TinyOS and demonstrate its performance in a real testbed of Mica2 nodes. The algorithm does not require any time synchronization and is shown to be effective in adapting to local topology changes without incurring global overhead in the scheduling. Because of these features, it can also be used even for other scheduling problems such as frequency or code scheduling (for FDMA or CDMA) or local identifier assignment for wireless networks where time synchronization is not enforced. We further evaluate the effect of the time-varying nature of wireless links on the conflict-free property of DRAND-assigned time slots. This experiment is conducted on a 55-node testbed consisting of the more recent MicaZ sensor nodes.     

无线网状网组网技术及实验研究

面对日益增长的高速无线因特网接入需求,传统的无线接入方式,如蜂窝网、无线局域网（WLAN）面临许多挑战,而无线网状网（WMN）作为因特网“最后一公里”接入方案,提供一种灵活而低成本的多跳通信,也将成为各种无线网络融合的主要技术。针对这一极具发展前途的网络结构,从WMN的两种典型应用出发,文章从网络配置、功率控制、移动性管理和接入控制以及路由协议设计等方面说明了WMN组网中的相关问题和技术,对WMN与移动自组织（Ad hoc）网路由协议的设计进行了对比,并给出了一种基于WLAN和第二层交换技术的WMN试验床实现方案。     

A dynamic location management scheme for next-generation multitierPCS systems

Global wireless networks enable mobile users to communicate regardless of their locations. One of the most important issues is location management in a highly dynamic environment because mobile users may roam between different wireless systems, network operators, and geographical regions. A location-tracking mechanism is introduced that consists of intersystem location updates and intersystem paging. Intersystem update is implemented by using the concept of boundary location area, which is determined by a dynamic location update policy in which the velocity and the quality of service are taken into account on a per-user basis. Also, intersystem paging is based on the concept of a boundary location register, which is used to maintain the records of mobile users crossing the boundary of systems. This mechanism not only reduces location-tracking costs, but also significantly decreases call-loss rates and average-paging delays. The performance evaluation of the proposed schemes is provided to demonstrate their effectiveness in multitier personal communication systems