Preface xv Acknowledgments xvii 1 Overview 1 1.1 History of Mobile Cellular Systems 1 1.1.1 First Generation 1 1.1.2 Second Generation 2 1.1.3 Generation 2.5 5 1.2 Overview of 3G 8 1.3 Proposals for 3G Standard 10 1.3.1 WCDMA 10 1.3.2 Advanced TDMA
自2004 年，众多IT 公司基于WiFi 商业模型发展出了WiMAX 技术，该技 术凭借全新增强的空中接口和基于I P 的网络对基于传统电信模式的U M T S 技术（尤其是HSDPA 技术）产生了巨 大挑战。为应对此挑战，3GPP 决定开 发能和W i M A X 抗衡的、以先进的 O F D M / O F D M A 接入为核心技术、支 持20MHz 系统带宽的、具有相似甚至 更高性能的技术以及更扁平高效的网络 架构，长期上也可以在未来IMT-Advanced 标准化上保持技术的竞争优
The present document has been developed within the 3rd Generation Partnership Project (3GPP TM) and may be further elaborated for the purposes of 3GPP. The present document has not been subject to any approval process by the 3GPP Organizational Part
