基于WiMAX技术5.8G无线专网射频系统设计

WiMAX(即802.16)是一种迅速崛起的城域网无线宽带技术,能够为家庭和企业用户提供高速因特网接入的"最后一英里"解决方案.WiMAX技术正成为通信领域新的市场增长点,缘于此,我们针对5.8G无线专网射频收发系统进行了研究,研制出在成本、性能上都具有很强竞争力的无线专网产品.整个射频收发系统集成设计在8层PCB板上,测试结果满足802.16标准射频指标要求.     

垂直领域的应用优势亦适于中国

在运营商市场，WiMAX被公认为很适合“个人宽带”应用。而在铁道、电力、应急通信、新能源、采矿、市政交通、平安城市等专网领域，WiMAX已经发挥出实际作用。     

WiMAX技术及其应用

WiMAX以其传输速率高、建网速度快、建设成本低、覆盖面积广、频谱效率高等特点成为未来最富有竞争力的无线宽带技术之一.WiMAX除能提供公众网络的语音/数据等业务外,最先会在专业网络中获得大规模的应用,尤其是在城市安防、公安消防、智能交通、防洪抗灾、政府办公等专网领域具有显著的优势,逐渐成为专网用户、电信运营商,尤其是网络基础设施相对匮乏地区运营商关注的无线宽带技术.     

WiMAX进入中国市场的路径分析

文章从研究中国公众移动市场、信息化专网市场及"无线城市"市场的角度出发,分析了WiMAX进入中国市场的路径,指出"无线城市"是WiMAX进入中国市场的最佳路径。     

WiMAX开始在全球部署

从2006年年初以来，WiMAX在美国、欧洲、亚太，甚至在南美和阿拉伯国家等都在逐渐升温，从政府部门、监管机构，到运营商，都有积极的动作，使得WiMAX技术的施行和应用有了实质性的进展。目前给人的主要印象是，具有一定技术优势的WiMAX人气日高，已经被广泛接纳；亚洲将会成为WiMAX的重要市场；WiMAX将逐渐走向成熟，形成坚实的产业链，并降低成本；WiMAX和3G各有所长，互为补充，不会威胁3G的发展；作为爵前最大问题的WiMAX全球频率协调问题，也不会阻挡WiMAX前进的步伐。     

WiMAX在全球有24个网络进入商用阶段

从2006年年初以来，WiMAX在美国、欧洲、亚太甚至南美和阿拉伯等国家和地区逐渐升温，从政府部门、监管机构到运营商，都有积极的动作，使得WiMAX技术的施行和应用有了实质性的进展。目前给人的主要印象是，具有一定技术优势的WiMAX人气日高，已经被广泛接纳；亚洲将会成为WiMAX的重要市场；WiMAX将逐渐走向成熟，形成坚实的产业链，并降低成本；WiMAX和3G各有所长，互为补充，不会威胁3G的发展；作为目前最大问题的WiMAX全球频率协调问题，也不会阻挡WiMAX前进的步伐。     

北电WiMAX和4G解决方案概述

WiMAX作为一种无线宽带接入技术与现有的固定无线接入技术相比，在频谱利用率、容量、覆盖半径以及QoS等方面都有着一定的优势。因此，目前业界对WiMAX的发展前景非常关注，甚至在争论WiMAX与3G的关系。一方面，与其他宽带无线技术相比WiMAX具有组网灵活、高容量、覆盖广、可管理等优点，而另一方面，WiMAX在频谱资源、漫游、无线优化、运营等方面也面临着诸多问题。北电网络（中国）有限公司的《北电WiMAX和4G解决方案概述》一文介绍了北电网络公司WiMAX解决方案的特点以及该方案与4G技术的关系，并归纳了其公司在WiMAX领域所取得的主要成就，这些信息对于运营商和业内人士全面了解北电网络公司的相关产品提供了有益的参考。     

中兴通讯WiMAX发展现状和产品优势

备受瞩目的WiMAX16e技术，由于其与生俱来的移动和宽带的完美结合，必将对通信行业带来革命性的影响。由于WiMAX论坛的成员涉及到移动通信产业链的各个环节，包括终端、芯片、设备生产厂家和众多的电信运营商、SP等，使得WiMAX16e在诞生之日就已经具有了非常完善的市场推动引擎，可以预见WiMAX16e在未来的无线宽带移动通信领域将占有相当重要的主导地位。     

持续创新,成就未来——中兴通讯WiMAX发展现状和产品亮点

备受瞩目的WiMAX 16e技术,由于其与生俱来的移动和宽带的完美结合,必将对通信行业带来革命性的影响.而且由于WiMAX论坛的成员涉及到移动通信产业链的各个环节,包括终端、芯片、设备生产厂家和众多的电信运营商、SP等,使得WiMAX16e在诞生之日就已经具有了非常完善的市场推动引擎,可以预见WiMAX 16e在未来的无线宽带移动通信领域将占有相当重要的主导地位.     

持续创新，成就未来——中兴通讯WiMAX发展现状和产品亮点

备受瞩目的WiMAX16e技术，由于其与生俱来的移动和宽带的完美结合，必将对通信行业带来革命性的影响。而且由于WiMAX论坛的成员涉及到移动通信产业链的各个环节，包括终端、芯片、设备生产厂家和众多的电信运营商．SP等，使得WiMAX16e在诞生之日就已经具有了非常完善的市场推动引擎，可以预见WiMAX16e在未来的无线宽带移动通信领域将占有相当重要的主导地位。[编者按]     

在众说纷纭中行进的WiMAX

WiMAX在全球的发展遇到诸多挑战和阻力，如：与HSPA和EV-DO等其他移动宽带技术的竞争，没有可供使用的频谱，部分运营商和设备商的推出，等等。但WiMAX的支持者并未因此而停止对WiMAX的推进，Intel、北电网络、Sprint Nextel、摩托罗拉、Vodafone等都在通过各种方式努力推进WiMAX的发展。对WiMAX的频率问题进行了解析，并对WiMAX的市场前景进行了展望。     

Quality of service models for heterogeneous networks: overview and challenges

The proliferation and convergence of different types of wired, wireless and mobile networks (such as WiMAX, Wireless Mesh Networks, WPANs, WLANs, etc) and cellular-based networks are crucial for the success of next-generation networks. Traditional wired/wireless networks can hardly meet the requirements of future integrated-service networks which are expected to carry multimedia traffic with various quality of service (QoS) requirements. Therefore, it is necessary to develop efficient global control mechanisms that can maintain QoS requirements to maximize network resources utilization, and minimize operational costs on all the types of wireless mobile networks. In this paper, we present an overview of QoS paradigms for heterogeneous networks and focus on those based on deterministic and probabilistic QoS.     

Improvements to seamless vertical handover between mobile WiMAX and 3GPP UTRAN through the evolved packet core - [LTE part II: 3GPP release 8]

Recent mobile devices are integrated with multiple network interfaces. Users want their devices connected to the network anytime anywhere. It is highly feasible for a user to change connection to another network for users that leave the service area of its current serving network, where handover needs to be executed seamlessly such that ongoing service sessions are not interrupted. The handover operation not only requires switching the interfaces within a device but also involves seamless reconfiguration of the supporting networks. In this article, an improved IP-based vertical handover technology for mobile WiMAX [1, 2], 3GPP legacy systems (i.e., Global System for Mobile communications and Universal Mobile Telecommunications System) [3, 4], and 3G Long Term Evolution [5, 6] is presented, which is based on existing optimized handover techniques between mobile WiMAX and 3GPP accesses [7?9]. Formerly proposed 3GPP WiMAX optimized VHO solutions introduced new elements, such as the forward attachment function and access network discovery and selection function. The ANDSF supports the discovery of target access, and the FAF provides the functionality that authenticates the UE before the execution of VHO. However, the previous technique has limitations that result in data loss and abnormal disconnection to the source access [7?9]. This article provides a solution by introducing an additional network element called the data forwarding function (DFF) that eliminates the data loss during VHO execution. In addition, the DFF resolves the problem of abrupt disconnection to the source network. The simulation results show that the proposed VHO technique is effective in minimizing data loss during VHO execution between mobile WiMAX and 3GPP networks. As the proposed solution of this article is an IP based handover solution, it can be similarly applied to other communication networks.     

Mobile WiMAX systems: performance and evolution

Mobile WiMAX was successfully adopted by ITU as one of the IMT-2000 technologies in November 2007. Since then mobile WiMAX (a.k.a. IP-OFDMA) has officially become a major global cellular wireless standard along with 3GPP UMTS/HSPA and 3GPP2 CDMA/ EVDO. Mobile WiMAX is an OFDM-based technology available for deployment today, and new WIMAX devices come to market at much reduced cost than that of current 3G solutions. Currently over 260 service providers are deploying fixed, portable and mobile WiMAX networks in 110 countries. This article provides an overview of the mobile WiMAX system and its performance under various configurations, channel conditions, and types of data traffic. Furthermore, the article provides an overview of mobile WiMAX evolution.     

轮询系统的演进及发展

近年来,轮询系统广泛应用到通信及计算机网络等领域。为进一步促进轮询系统理论的研究和发展,使其在宽带通信网络、WLAN、WSN、蓝牙网络、Ad Hoc网络、4G网络、WiMAX、EPON、OFDM和RFID等MAC协议设计或改进等方面发挥出更多、更好的效益,从轮询系统演进历程及其具体应用入手,给出了轮询系统的基本概念、控制原理、不同分类以及特性参数,介绍了当前轮询系统的研究现状,比较了轮询系统的研究分析方法,提出了轮询系统研究发展的若干重要方向。     

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.     

Interoperability Among Broadband Wireless Technologies in a Testbed Environment

As we move towards the next generation networks, one of the fundamental issues to consider is the integration of wireless technologies. Integrated networks will have impressive capabilities as well as cumbersome challenges in areas such as Radio Resource Management (RRM), Quality of Service (QoS), Security, Mobility, and Power Management. In this paper, we tackle one of the challenges facing researchers and developers in this area. The main objective of this research was to build an integrated WiFi–WiMAX network in a test-bed environment, and to investigate the effects of integration on the QoS performance. This study is based on practical deployment and measurements in a laboratory environment. We successfully implemented an integrated system and experimented with various QoS scenarios. A set of RRM schemes were defined for the integrated networks and actual results collected from network analyzer showed that the QoS requirements were met throughout the WiFi–WiMAX networks.     

Seamless integration of mobile WiMAX in 3GPP networks

As the wireless industry makes its way to the next generation of mobile systems, it is important to engineer solutions that enable seamless integration of emerging 4G access technologies within the currently deployed and/or evolved 2G/3G infrastructures. In this article we address a specific case of such a seamless integration, that of mobile WiMAX in evolved 3GPP networks. In this context we investigate the architecture and the key procedures that enable this integration, and we also introduce a novel handover mechanism that enables seamless mobility between mobile WiMAX and legacy 3GPP access, such as UTRAN or GERAN. The core characteristic of this novel handover mechanism is that mobile terminals do not need to support simultaneous transmission on both WiMAX and 3GPP accesses; therefore, it mitigates the RF coexistence issues that exist otherwise and improves handover performance. In addition, we provide a brief overview of mobile WiMAX and the evolved 3GPP network technologies, and we set the appropriate background material before presenting our proposed handover mechanism. Our main conclusion is that integrating mobile WiMAX in evolved 3GPP networks is a compelling approach for providing wireless broadband services, and mobility across WiMAX and 3GPP access can become seamless and efficient with no need for mobile terminals to support simultaneous transmission on both types of access.     

Performance Modeling of an Integrated Wireless Network Using WiMAX as Backhaul Support for WiFi Traffic

We propose an analytic model for an integrated wireless network using WiMAX as backhaul support for WiFi traffic and evaluate the system performance. A unique feature for the proposed model is that the WiFi traffic completely reflects the realistic user mobility. A WiFi call can be overflowed to its overlaid WiMAX cell when it is rejected at the WiFi cell; a WiFi call may also work for some period of time in the WiFi cell and then make a vertical handoff to its overlaid WiMAX cell when it wants to move from its current WiFi cell (e.g., office) to its target WiFi cell (e.g., airport). Further, the target WiFi cell may be located at another place in the same WiMAX cell, or at a different WiMAX cell. We use Markov processes to model the dynamics of the WiMAX traffic and WiFi traffic including the overflowed WiFi traffic, the vertical handoff WiFi traffic, the horizontal handoff WiFi traffic, and the take-back WiFi traffic. We derive the explicit expressions of various traffic arrival rates and performance metrics and analyze the performance improvement of the WiFi traffic and the impact on the WiMAX traffic due to backhaul support. Numerical results are provided for further understanding of the gain and loss of the integrated architecture.     

WiMAX networks: from access to service platform

Recently, WiMAX has been proposed as an attractive wireless communication technology for providing broadband access for metropolitan areas. Despite its salient features from the technical perspective, the success of the WiMAX network depends on its capability of providing cost-effective solutions for a variety of existing and potential services. To address this issue, we advocate the design of a new network layer that can support multihop communications efficiently in WiMAX networks and that can fully exploit the features of the WiMAX standards. In particular, we first identify services that are important for broadband wireless network providers and investigate the requirements for different services. We then discuss now to design WiMAX networks by considering issues of efficiency, security, and reliability. The key observation is that WiMAX can be properly complemented by advanced connection management and network coding techniques.