进阶长期演进技术（又译作长期演进技术升级版，英语：LTE-Advanced，简称LTE-A，在中国称4G+）是长期演进技术（LTE）的提升版本，理论上网速度比3G快十倍以上，也是4G规范的国际高速无线通讯标准。它是一个行动通讯标准，于2009年末正式作为4G系统递交至ITU-T，并先后通过国际电信联盟、IMT-Advanced，最终于2011年3月为3GPP完成。[1]它被3GPP标准化成为主要的LTE增强标准。
进阶LTE的目标是要达到并超越国际电信联盟的要求。该版本与第一个版本LTE设备兼容，并与第一个版本LTE共享频段。
简介
第一个版本的LTE格式是由日本电信商NTT DoCoMo所提出的，并且被承认为国际标准，最初于2009年12月在瑞典和挪威提供服务。以1GB视频需要的下载时间来说，3G频宽需要约10分钟，但若是采用4G LTE，不到1分钟即可完成下载。同时高频宽在电话语音时将语音资料切割成分组来传送，能达到更佳的音质，称为“VoLTE（Voice over LTE）”。
同时机器类型通讯（Machine-Type Communications，简称MTC）协定让4G有跨入物联网的重要能力，这是一个适合低资料量、低功耗及低成本设计的通讯机制。MTC未来使用的频宽会以1.4MHz为主并运作在LTE双工模式中（例如全双工/半双工FDD或TDD）。而设备对设备通讯（Device-to-Device，简称D2D）协定让手机设备间在无基地台情况下短距互联，第一线急难救助人员在资讯传输、沟通互动与讯息交换的灾区需求上此一功能可以发挥效果。[2]
技术
- 非授权频段(LTE in unlicensed spectrum，简称LTE-U)
- 载波聚合(Carrier Aggregation，简称CA):载波聚合技术是传统多载波技术的发展。其核心思想是把至多5个连续或离散频谱划分为多个成员载波（Component Carrier，CC），允许终端在多个子频带上同时进行数据收发。
- 高阶MIMO(Elevation Beamforming / Full-Dimension MIMO，简称EB/FD MIMO)
- 干扰协调(Enhanced Inter-Cell Interference Coordination, 简称eICIC)
- 机器类型通讯(Machine-Type Communications，简称MTC)
- 设备对设备通讯(Device-to-Device，简称D2D)
- 多人传输技术(multi-user transmission techniques)
- 室内定位(Indoor positioning)
- 小区群播服务(Single-cell Point-to-Multipoint，简称SC-PTM)
参考文献
- ↑ Stefan Parkvall, Erik Dahlman, Anders Furuskär et al; Ericsson, Robert Syputa, Maravedis; ITU global standard for international mobile telecommunications ´IMT-Advanced´; LTE-Advanced - Evolving LTE towards IMT-Advanced ; Vehicular Technology Conference, 2008. VTC 2008-Fall. IEEE 68th 21-24 Sept. 2008 Page(s):1 - 5.
- ↑ The fastest LTE radio cell in Germany and mobile VoLTE in live network. [2017-10-03].
- Qualcomm
- Harri Holma, Antti Toskala, LTE for UMTS - OFDMA and SC-FDMA Based Radio Access, John Wiley & Sons 2009, ISBN 978-0-470-99401-6 Chapter 2.6: LTE Advanced for IMT-advanced, pp 19–21.
- Moray Rumney (editor), LTE and the Evolution to 4G Wireless: Design and Measurement Challenges, Agilent Technologies Publication 2009, ISBN 978-0-470-68261-6, Chapter 8.7: Proving LTE Advanced, p 425
- Preben E. Mogensen, Tommi Koivisto, Klaus I. Pedersen 1, et al.; Nokia Siemens Networks;LTE Advanced: The Path towards Gigabit/s in Wireless Mobile Communications, Wireless VITAE'09.
- ITU-R Confers IMT-Advanced (4G) Status to 3GPP LTE – LTE-Advanced is officially 4G
- The LTE / LTE-Advanced Guide – a semi-annual publication on LTE / LTE-Advanced, May and November 2010 publications are now available
- LTE-Advanced Technology Introduction[永久失效链接] - This white paper summarizes necessary improvements, which are known as LTE-Advanced
- Introducing LTE-Advanced - Application Note
- LTE Bitstream Verification[永久失效链接] - Application Note about verification of baseband data of LTE/LTE-A-ready products.
- LTE Transmission Modes and Beamforming[永久失效链接] - This white paper discusses the basics of beamforming and explains the eight MIMO transmission modes in LTE Release 9.
外部链接
- LTE-Advanced page on Qualcomm site
- 3GPP Official 3GPP Standardisation Page on LTE-Advanced
- LTE-Advanced overview
- Future use of LTE A femtocells
- LTE Portal – 3GPP LTE / LTE-Advanced Technology, dedicated portal created for information sharing, collaboration, and networking