文档介绍：LTE Overview
Sun Changsong
LBTS I&V HZ
2009-05-05
Outline
LTE motivation and background
3GPP schedule
LTE Key Technology
LTE architecture
LTE physical Layer
LTE layer 2/3
LTE Peak Bit Rates
Spectral Efficiency
Voice evolution in LTE/SAE
Nokia works LTE
LTE motivation and background
Wireline evolution pushes higher data rates
Wireless data usage requires more capacity
Flat rate pricing pushes efficiency
LTE expectations
Other technologies push wireless capabilities
Drivers for LTE
HSDPA data packages introduced  traffic explodes
HSDPA data volume
ADSL, VDSL, GPON…
40 Mbps, 80 Mbps,…
10 MHz, 20 MHz,…
Elisa Flat rate 10-30 €/month
Several customers with >3 TB/day HSDPA traffic
3GPP schedule
LTE in 3GPP Release 8
3GPP and Operator Requirements
Packet Switched Domain Optimized
Server-UE RTT <30 ms
Access Delay <300 ms
Peak Rates UL/DL 50/100 Mbps
Good Mobility and Security
Improve Terminal Power Efficiency
Frequency Allocation Flexibility with , 5, 10, 15 and 20 MHz Allocations
WCDMA evolution work to continue
3-4 times higher capacity expected than with Release 6 HSDPA/HSUPA reference case
Study Phase
2004: 3GPP workshop on UTRAN Long Term Evolution
03/2005 Start of the study
12/2005 Multiple Access selected
03/2006 eNB/Core functional split selected
09/2006 close of the study item & approval of work plan
Release 8 Stage 3 Output
06/2008 baseline
09/2008 baseline
Major PHY updates.
12/2008 baseline
Major MAC updates.
03/2009 baseline
Major L3 updates. for RRC.
LTE Key Technology
The Beauties of LTE
Channel only changes amplitude and phase of subcarriers
Fast Link Adaptation
due to channel behaviour
Short TTI = 1 ms
Transmission time interval
Advanced Scheduling Time & Freq. (Frequency Selective Scheduling)
TX
RX
Tx
Rx
MIMOChannel
DL: OFDMA
UL: SC-FDMA
scalable
HARQ: Hybrid Automatic Repeat Request
64QAMModulation
1
2
2
1
NACK
ACK
Rx Buffer
Combined decoding
LTE Architecture
Our Key Architectural C