tdlte原理及常见优化案例分析.ppt

TDLTE原理及常见优化案例分析
TDLTE原理及常见优化案例分析TDLTE原理及常见优化案例分析Presentation / Author / Date IntroductionIt provides the basic bit transmission functionality over air
LTE physical layer based on OFDMA downlink and SC-FDMA in uplink direction
This is the same for both FDD and TDD mode of operation
No need of RNC like functional element
Everything radio related can be terminated in the eNodeB
System is reuse 1, single frequency network operation is feasible
No frequency planning required
There are no dedicated physical (neither transport) channels anymore, as all resource mapping is dynamically driven by the scheduler
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Introduction
It provides the basic bit transmission functionality over air
LTE physical layer based on OFDMA downlink and SC-FDMA in uplink direction
This is the same for both FDD and TDD mode of operation
No need of RNC like functional element
Everything radio related can be terminated in the eNodeB
System is reuse 1, single frequency network operation is feasible
No frequency planning required
There are no dedicated physical (neither transport) channels anymore, as all resource mapping is dynamically driven by the scheduler
Presentation / Author / Date
帧结构概述
无线帧结构1：FDD模式
无线帧长度为10ms，包含20个时隙，共10个子帧。
每个子帧长度为1ms，由相邻两个时隙构成，。
任何一个子帧即可以作为上行，也可以作为下行。
无线帧结构2：TDD模式
每个10ms无线帧包括两个时长为5ms的半帧，每个半帧由4个数据子帧和一个特殊子帧组成。
支持5ms和10ms上下行切换点
子帧0和子帧5以及DwPTS永远预留为下行传输。
在5ms 切换周期情况下，UpPTS、子帧2和子帧7预留为上行传输。
在10ms 切换周期情况下，UpPTS、子帧2预留为上行传输，子帧7和子帧9预留为下行传输。
Presentation / Author / Date
TDD帧结构
Subframes 1, 6为特殊子帧，包含 DwPTS 、GP、 UpPTS三个特殊区域。这三个特殊区域总时长为1ms，各自的时长可灵活配置。
常规CP（循环前缀），每个子帧有14个符号组成，扩展CP有12个符号组成。
DwPTS: Downlink Pilot time Slot
UpPTS: Uplink Pilot Time Slot
GP: Guard Period to separate between UL/DL
More info: - (03/09)
Presentation / Author / Date
特殊子帧传输内容
1、DwPTS（下行链路导频时隙）
类似于较短的下行链路子帧，传送下行控制信息
传送下行参考信号
也可以传送下行数据
PSS（主同步信道）固定位于第3个符号
2、UpPTS（上行导频时隙）
传送SRS探测参考信号或短RACH信号
3、GP（保护周期）
用于上下行转换
GP长度决定了最大