1. LTE Introduction
Tzu-chin Liu
15th March 2012

2. Outline Overview Network architecture Protocol stack Resource element
Frame structure
TDD frame configuration
TDD special subframe
MIMO
Random access procedure

3. LTE Overview
LTE – Long Term Evolution: The 4th generation telecommunication standards.
Evolved from the 3GPP system.(R8)
RAN: LTE
Core: SAE(System Architecture Evolution)
Characteristics:
Packet switching
All – IP network
Higher data rate
OFDMA based
MIMO supported
Lte 是什麼? 是現今4G通訊標準之一
由3gpp演進而來
最大的特色: all ip , pkt switching, high data rate, broadband?
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使用OFDMA, MIMO等技術; duplex有TDD/FDD

4. SAE – System Architecture Evolution
接下來看LTE的network Arch.
一般所說的LTE其實包含了兩套標準: LTE/SAE
其中LTE是定義radio access network, SAE 是定義core network.
RAN就是指e-utran這邊 從UE(手機)連上基地台enodeB, 接著才練上核心網
他的core裡有幾個重要的entity:
第一個是mme: …

5. Protocol Stack
User plane:
Control plane:

6. Resource element The basic unit when allocating carrier resource.
Resource Element(RE):
One subcarrier by one symbol
Resource Block(RB):
12 subcarriers by 7 symbol
Resource Element Group(REG):
For control plane
One REG has 4 or 6 REs.

7. LTE Frame Structure One radio frame has 10 ms: Duplexing:
10 subframes, each of 1 ms.
Duplexing:
FDD
TDD
在傳輸時把時間單位切成一個個的frame
一個frame是10millisec.

8. LTE TDD Frame UL-DL configuration: Special Subframe:
LTE TDD can have 7 UL-DL subframe configurations.
Special Subframe:
Provide a gap to allow switching from DL to UL a transition subframe.
接下來要講怎麼樣去透過frame的設定來做雙工

9. LTE TDD UL-DL configuration

10. MIMO Multiple-Input Multiple-Output: Better throughput
multiple antennas at both the transmitter and receiver to improve communication performance.
Better throughput
Longer transmission distance

11. MIMO modes Downlink Transmission Mode:
Release 8 have defined 7 transmission modes.

12. Random Access Procedure
Random access purpose: Set up the RRC (Radio Resource Control) connection when:
Idle state or initial power on
Handover
Synchronization
Reset RRC

13. Random Access Procedure

14. Q & A

15. References TDD LTE Air Interfaces v.1
TS GPP System Architecture Evolution (SAE): Security architecture
TS Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures
TS Evolved Universal Terrestrial Radio Access (E-UTRA); Medium Access Control (MAC) protocol specification