回顾过去十年，无线通信的蓬勃发展正从各方个面改变着我们的生活——从只支持窄带语音业务的2G蜂窝电话，到可以提供无线Internet接入的3G网络，到可以提供最后一公里解决方案的BWA,再到将有线网络的速度无线化的WLAN。高速增长的Internet和多媒体业务，推动着无线通信速率从儿十Kbps发展到几十Mbps甚至更高。WiMax技术的出现正好满足了人们对无线Internet的需求，如果说无线局域网解决了“最后一百米”的接入问题，那么WiMax技术则是“最后一公里”接入的最佳解决方案。
在诸多可以应对宽带无线信道挑战的物理层技术中，OFDM具有更高的频谱利用率和更强健的抗多径衰落能力，被证明是宽带无线系统最有效的物理层调制技术。本论文将重点研究WiMax所支持的OFDM物理层调制技术和OFDMA多址技术的设计与实现。
WiMax网络管理系统采用SNMP协议，并基于Manager/Agent模型而设计。本论文主要研究系统设计以及EMS Manager和EnvoySNMP Agent的设计与实现。
MDI作为MAC与PHY的通信桥梁，对系统的性能有着举足轻重的影响。本论文还将研究MDI的设计、实现和性能。
关键词:WiMax, IEEE802.16, MDI, OFDMA，网管系统
Abstract
In retrospect to the past decade, the thriving development in wireless communications have been changing our life in all aspects——from 2G cell phones that support only narrow band voice, to 3G networks that provide mobile Internet access, to BWAs that offer the last mile wireless access solutions, and to wireless LANs that enable wire-line speed wirelessly. The rapid growth of Internet and multimedia services has been driving the wireless data rate from tens of Kbps to tens of Mbps and even beyond. Such booming demands provide a driving force for the large span of research in high speed wireless systems. WiMax technology satisfies the need of wireless Internet. WLAN resolves the problem of last handerd meters access. and then WiMax will become the best scheme of last one kilometer access.
Among many physical layer techniques developed to cope with the broadband radio channel's challenges, Orthogonal Frequency Division Multiplexing (OFDM) has been proven to be the most cost effective modulation scheme for broadband wireless systems due to its high spectral efficiency and inherent robustness against multipath fading. This paper will focus on the design and implementation of OFDM PHY and OFDMA mufti access technology supported by WiMax system.
The NMS system of WiMax adopts SNMP protocol which is designed based-on Manager/Agent model. This paper will present the design and implementation of WiMax NMS system architeucure, EMS Manager and EnvoySNMP Agent.
MCU DSP Interface (MDI) is the bridge between MCU and DSP communications, which affects the system performance significantly. The detailed design of MDI is described in this paper, with implementation and testing method.
KEY WORDS: WiMax, IEEE802.16, MDI, OFDMA, NMS
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