通信系統(tǒng)演進(jìn)介紹ppt課件(已修改)
2025-01-27 13:29 本頁面
【正文】 2022/2/12 1 數(shù)字無線傳輸 寬帶無線與多媒體中心 王德勝 2022 2022/2/12 2 第 1章 概論 引言 ☆移動(dòng)通信已成為當(dāng)代通信領(lǐng)域內(nèi)發(fā)展?jié)摿ψ畲?、市?chǎng)前景最廣的熱點(diǎn)技術(shù)， ☆移動(dòng)通信用戶的增長遠(yuǎn)遠(yuǎn)超過了人們的預(yù)期， ☆未來的無線便攜終端數(shù)量會(huì)超過目前計(jì)算機(jī)聯(lián)網(wǎng)的數(shù)量， ☆其業(yè)務(wù)也從面向語音通信轉(zhuǎn)變?yōu)槊嫦蚨嗝襟w數(shù)據(jù)通信 2022/2/12 3 展望 ☆高頻譜效率 ☆高功率效率 ☆高性價(jià)比 ☆高質(zhì)量的服務(wù)體系：扁平、透明、按需區(qū)分服務(wù) 2022/2/12 4 ☆傳輸方式變化 ☆ 交換方式變化 ☆服務(wù)內(nèi)容變化 ☆用戶容量增大 ☆覆蓋范圍與全球漫游 ☆效率提高 1G到 4G的發(fā)展 2022/2/12 5 European research on 3G started in 1989 within the RACE I program and 1991 in RACE II European research on systems beyond 3G started in 1999 within the IST program 1980s 1990s 2022s 2022s 1G+ 1G 2G+ 2G 3G+ 3G Beyond 3G+ Beyond 3G Analog Wideband Digital ??? Digital European research on 3G continued in 1995 within the ACTS program Framework Program 6 on future systems full mercial deployment trials standardisation research Evolution of mobile munication systems 2022/2/12 6 Wireless data already be introduced in second generation mobile First Generation ? Analogue ? Circuit switched ? Basic voice telephony ? Low capacity ? Limited local and regional coverage Second Generation ? Digital ? Circuit switched ? Voice plus basic data applications ? Low data speed ? Enhancements towards ? packet switching ? higher data rates ? Transnational and global roaming ? Digital ? Packet and circuit switched ? Advanced data (multimedia) applications ? Fast data access ? Global coverage ? Global roaming Third Generation Beyond Third Generation ? Digital ? Packet switched ? All IP based (IPv6) ? More advanced multimedia applications ? User in control ? Flexible platform of plementary access systems ? High speed data ? Improved QoS ? Global coverage ? Global roaming Paradigm shift from 1st generation towards beyond 3G 2022/2/12 7 2022/2/12 8 一體化網(wǎng)絡(luò)架構(gòu) WiFi (WaveLAN) Radio Hub Cable, xDSL, V90 10/100BaseT Wireless LAN Bluetooth Wireless PAN Multimedia amp。 Messaging Server ? integrated voice and data ? video postcards ? incall image up/download ? codec converter ? bandwidth manager ? store amp。 forward ? playback Content Micro BS BTS UMTS/GSM CDMA2022 Wireless Backbone and Gateways Location Services IP Network 2022/2/12 9 Drivers of 3G Beyond 3G evolution …but difficult ? to extend to higher data rate with CDMA only technology。 ? to provide various services with different QoS ? to have enough frequency resource to acmodate more subscribers ? Drawbac
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