【正文】 信基礎(chǔ)設(shè)施的手段。它用數(shù)字信號(hào)處理語(yǔ)言描述電信元件，以軟件程序下載成數(shù)字信號(hào)處理硬件（ DSPH， Digital Signal Pocessing Hardware）。 OFDM已用于 Mbit/s 高比特率數(shù)字用戶(hù)線(xiàn)（ HDSL）， 6 Mbit/s不對(duì)稱(chēng)數(shù)字用戶(hù)線(xiàn)（ ADSL）， 100 Mbit/s 甚高速數(shù)字用戶(hù)線(xiàn)（ VDSL），數(shù)字音頻廣播和數(shù)字視頻廣播等。 OFDM應(yīng)用于 5 GHz上提供 54 Mbit/s 無(wú)線(xiàn)本地網(wǎng) IEEE a和 IEEE ，高性能本地域網(wǎng)絡(luò) Hiper LAN/2 和 ETSIBRAN，還作為城域網(wǎng) IEEE （ ISDBT）標(biāo)準(zhǔn)。以具有通用開(kāi)放無(wú)線(xiàn)結(jié)構(gòu)（ OWA， Open Wireless Architecture），兼容多種模式在多種技術(shù)標(biāo)準(zhǔn)之間無(wú)縫切換。當(dāng)今大多數(shù)無(wú)線(xiàn)通信系統(tǒng)都是基于蜂窩無(wú)線(xiàn)電概念之上的。在設(shè)計(jì)差錯(cuò)控制碼、均衡器和其他用來(lái)消除信道所產(chǎn)生的 瞬時(shí)影響的部件時(shí)，這種假設(shè)時(shí)合理的。把服務(wù)區(qū)內(nèi)可用的無(wú)線(xiàn)頻譜都分配給每一個(gè)簇，使同一個(gè)簇內(nèi)的小區(qū)不共用相同的信道。例如，在不增加分配給系統(tǒng)的無(wú)線(xiàn)頻譜帶寬的前提下，得到高容量（大量的用戶(hù)）的一種措施是，通過(guò)減小蜂窩系統(tǒng)簇的大小 N，來(lái)縮短信道復(fù)用距離。這樣，無(wú)論何時(shí)何地你都將能夠通過(guò)無(wú)線(xiàn)網(wǎng)絡(luò)獲得大量的媒體信息和娛樂(lè)。 在休閑度假中，你倒了一個(gè)新城市。 這一段提出了一些主要的技術(shù)和發(fā)展的簡(jiǎn)短觀(guān)點(diǎn)。 全球革命性的提高傳輸速率將是原來(lái)的 GSM和 TSMA運(yùn)營(yíng)商利用現(xiàn)有的設(shè)備提供 3G服務(wù)。愛(ài)立信已經(jīng)研制出了藍(lán)牙裝置，包括 T36藍(lán)牙手機(jī)和藍(lán)牙掌上設(shè)備。s foundation, has had the land honeyb mobile munication, the satellite munication as well as the wireless Inter munication, these mailing address caused the correspondence appearance to have the huge change, used the digital technique the modern wireless munication already to permeate the national economy each domain and people39。 6) Each kind of work tends the fusion. The understanding, grasps these tendencies has the vital practical significance to the mobile munication operator and the equipment manufacturer. 3 Research of cellular wireless mination system summarize A wide variety of wireless munication systems have been developed to provide access to the munications infrastructure for mobile or fixed users in a myriad of operating environments. Most of today’s wireless systems are based on the cellular radio concept. Cellular munication systems allow a large number of mobile users to seamlessly and simultaneously municate to wireless modems at fixed base stations using a limited amount of radio frequency (RF) spectrum. The RF transmissions received at the base stations from each mobile are translated to baseband, or to a wideband microwave link, and relayed to mobile switching centers (MSC), which connect the mobile transmissions with the Public Switched Telephone Network (PSTN). Similarly, munications from the PSTN are sent to the base station, where they are transmitted to the mobile. Cellular systems employ either frequency division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA), or spatial division multiple access (SDMA) . Wireless munication links experience hostile physical channel characteristics, such as timevarying multipath and shadowing due to large objects in the propagation path. In addition, the performance of wireless cellular systems tends to be limited by interference from other users, and for that reason, it is important to have accurate techniques for modeling interference. These plex channel conditions are difficult to describe with a simple analytical model, although several models do provide analytical tractability with reasonable agreement to measured channel data . However, even when the channel is modeled in an analytically elegant manner, in the vast majority of situations it is still difficult or impossible to construct analytical solutions for link performance when error control coding, equalization, diversity, and work models are factored into the link model. Simulation approaches, therefore, are usually required when analyzing the performance of cellular munication links. Like wireless links, the system performance of a cellular radio system is most effectively modeled using simulation, due to the difficulty in modeling a large number of random events over time and space. These random events, such as the location of users, the number of simultaneous users in the system, the propagation conditions, interference and power level settings of each user, and the traffic demands of each user,bine together to impact the overall performance seen by a typical user in the cellular system. The aforementioned variables are just a small sampling of the many key physical mechanisms that dictate the instantaneous performance of a particular user at any time within the system. The term cellular radio system,therefore, refers to the entire population of mobile users and base stations throughout the geographic service area, as opposed to a single link that connects a single mobile user to a single base station. To design for a particular systemlevel performance, such as the likelihood of a particular user having acceptable service throughout the system, it is necessary to consider the plexity of multiple users that are simultaneously using the system throughout the coverage area. Thus, simulation is needed to consider the multiuser effects upon any of the individual links between the mobile and the base station. The link performance is a smallscale phenomenon, which deals with the instantaneous changes in the channel over a small local area, or small time duration, over which the average received power, is assumed constant. Such assumptions are sensible in the design of error control codes, equalizers, and other ponents that serve to mitigate the transient effects created by the channel. However, in order to determine the overall system performance of a large number of users spread over a wide geographic area, it is necessary to incorporate largescale effects such as the statistical behavior of interference and signal levels experienced by individual users over large distances, while ignoring the transient channel characteristics. One may think of linklevel simulation as being a vernier adjustment on the performance of a munication system, and the systemlevel simulation as being a coarse, yet important, approximation of the overall level of quality that any user could expect at any time. Cellular systems achieve high capacity (., serve a large number of users) by allowing the mobile stations to share, or reuse a munication channel in different regions of the geographic servi