1. Long Term Evolution (LTE) and System Architecture Evolution (SAE)
3 May 2007
Long Term Evolution (LTE) and System Architecture Evolution (SAE)
v1.0 3rd May 2007

2. Contents Why LTE/SAE? LTE Overview
3 May 2007
Contents
Why LTE/SAE?
LTE Overview
LTE technical objectives and architecture
LTE radio interface
RAN interfaces
SAE architechture [3GPP TS ]
Functions of eNB
Functions of aGW
GTP-U tunneling
Non-3GPP access tunneling
Testing challenges with LTE
LTE standardisation status

3. Why LTE/SAE? Packet Switched data is becoming more and more dominant
3 May 2007
Why LTE/SAE?
Packet Switched data is becoming more and more dominant
VoIP is the most efficient method to transfer voice data
 Need for PS optimised system
Amount of data is continuously growing
 Need for higher data rates at lower cost
Users demand better quality to accept new services
High quality needs to be quaranteed
Alternative solution for non-3GPP technologies (WiMAX) needed
LTE will enhance the system to satisfy these requirements.

4. LTE Overview 3GPP R8 solution for the next 10 years
3 May 2007
LTE Overview
3GPP R8 solution for the next 10 years
Peaks rates: DL 100Mbps with OFDMA, UL 50Mbps with SC-FDMA
Latency for Control-plane < 100ms, for User-plane < 5ms
Optimised for packet switched domain, supporting VoIP
Scaleable RF bandwidth between 1.25MHz to 20MHz
200 users per cell in active state
Supports MBMS multimedia services
Uses MIMO multiple antenna technology
Optimised for 0-15km/h mobile speed and support for up-to km/h
No soft handover, Intra-RAT handovers with UTRAN
Simpler E-UTRAN architecture: no RNC, no CS domain, no DCH

5. LTE technical objectives and architecture
3 May 2007
LTE technical objectives and architecture
User throughput [/MHz]:
Downlink: 3 to 4 times Release 6 HSDPA
Uplink: 2 to 3 times Release 6 Enhanced Uplink
Downlink Capacity: Peak data rate of 100 Mbps in 20 MHz maximum bandwidth
Uplink capacity: Peak data rate of 50 Mbps in 20 MHz maximum bandwidth
Latency: Transition time less than 5 ms in ideal conditions (user plane), 100 ms control plane (fast connection setup)

6. Mobility: Optimised for low speed but supporting 120 km/h
3 May 2007
Mobility: Optimised for low speed but supporting 120 km/h
Most data users are less mobile!
Simplified architecture: Simpler E-UTRAN architecture: no RNC, no CS domain, no DCH
Scalable bandwidth: 1.25MHz to 20MHz: Deployment possible in GSM bands.

7. From Ericsson, H. Djuphammar
3 May 2007
LTE radio interface
New radio interface modulation: SC-FDMA UL and OFDMA DL
Frequency division, TTI 1 ms
Scalable bandwidth MHz
TDD and FDD modes
UL/DL in either in same or in another frequncy
OFDMA has multiple orthogonal subcarries that can be shared between users
quickly adjustable bandwith per user
SC-FDMA is technically similar to OFDMA but is better suited for uplink from hand-held devices
Single carrier, time space multiplexing
Tx consumes less power
From Ericsson, H. Djuphammar

8. LTE/SAE Keywords aGW Access Gateway eNB Evolved NodeB
3 May 2007
LTE/SAE Keywords
aGW Access Gateway
eNB Evolved NodeB
EPC Evolved Packet Core
E-UTRAN Evolved UTRAN
IASA Inter-Access System Anchor
LTE Long Term Evolution of UTRAN
MME Mobility Management Entity
OFDMA Ortogonal Frequency Division Multiple Access
SC-FDMA Single Carrier Frequency Division Multiple Access
SAE System Architecture Evolution
UPE User Plane Entity

9. RAN interfaces X2 interface between eNBs for handovers
3 May 2007
RAN interfaces
eNB
X2 interface between eNBs for handovers
Handover in 10 ms
No soft handovers
Interfaces using IP over E1/T1/ATM/Ethernet /…
Load sharing in S1
S1 divided to S1-U (to UPE) and S1-C (to CPE)
Single node failure has limited effects S1
aGW
eNB X2 S8
aGW X2
eNB

10. SAE architecture [3GPP TS 23.401]
3 May 2007
SAE architecture [3GPP TS ]
GERAN
HSS
PCRF Gb
UTRAN
GPRS Core Iu S6
Rx+ S7 X1 S3 S4
Operator IP
services
(including IMS, PSS, ...)
eNB
MME UPE
SAE GW
PDN
SAE GW
SGi S1
S11 S5 X1 X2
aGW S2
Evolved Packet Core
eNB
Non-3GPP IP Access
Evolved RAN

11. SAE architechture [3GPP TS 23.401]
3 May 2007
SAE architechture [3GPP TS ]
TBD
eNB
HSS
PCRF S1 S7
S6a
aGW S5
PDN
SAE GW
S11
SAE GW
TBD
eNB X2
IASA S8
SGi
S11
aGW
Operator IP
service, including
IMS
TBD
Short descriptions of the LTE interfaces [Source: ]
eNB
aGW = MME/UPE
Evolved RAN

12. 3 May 2007
Functions of eNB
Terminates RRC, RLC and MAC protocols and takes care of Radio Resource Management functions
Controls radio bearers
Controls radio admissions
Controls mobility connections
Allocates radio resources dynamically (scheduling)
Receives measurement reports from UE
Selects MME at UE attachment
Schedules and transmits paging messages coming from MME
Schedules and transmits broadcast information coming from MME & O&M
Decides measurement report configuration for mobility and scheduling
Does IP header compression and encryption of user data streams

13. 3 May 2007
Functions of aGW
Takes care of Mobility Management Entity (MME) functions
Manages and stores UE context
Generates temporary identities and allocates them to UEs
Checks authorization
Distributes paging messages to eNBs
Takes care of security protocol
Controls idle state mobility
Control SAE bearers
Ciphers & integrity protects NAS signaling

14. Takes care of User Plane Entity (UPE) functions
3 May 2007
Takes care of User Plane Entity (UPE) functions
Terminates for idle state UEs the downlink data path and triggers/initiates paging when downlink data arrive for the UE.
Manages and stores UE contexts, e.g. parameters of the IP bearer service or network internal routing information.
Switches user plane for UE mobility
Terminates user plane packets for paging reasons

15. 3 May 2007
Functions S1

16. LTE Control Plane NAS NAS PDCP PDCP RRC RRC RLC RLC MAC MAC PHY PHY UE
3 May 2007
LTE Control Plane UE
eNB
aGW
NAS
NAS
PDCP
PDCP
RRC
RRC
RLC
RLC
MAC
MAC
PHY
PHY S1

17. LTE User Plane IP IP PDCP PDCP RLC RLC MAC MAC PHY PHY UE aGW eNB S1
3 May 2007
LTE User Plane UE
eNB
aGW IP IP
PDCP
PDCP
RLC
RLC
MAC
MAC
PHY
PHY S1

18. Header compression & encryption
3 May 2007
GTP-U tunneling
Header compression & encryption UE
UPE X1
eNB S1
S11
SAE GW S5
PDN
SAE GW
SGi
Server
Radio L1
MAC
PDCP
IPv6/v4 u
Application
TCP/UDP
RLC
IPv6/v4
TCP/UDP
Application IP
UDP
GTP-U L2 L1
Radio L1
MAC
RLC
PDCP
ENC IP
UDP
GTP-U L2 L1 IP
UDP
GTP-U L2 L1 L1 L2 IP
UDP
GTP-U L1 L2 L2 L1

19. Non-3GPP access tunneling
3 May 2007
Non-3GPP access tunneling UE AP
PDN
SAE GW HA
Server
WLAN S2
SGi
Application
TCP/UDP
IPv4/6
IPv4/6
MIP
MIP
UDP
UDP IP
IPv6/v4 IP IP IP IP L1 L2 L1 L2 L2 IP L1 L2 L2 L2 L2 L1 L1 L1 L1

20. Testing challenges with LTE
3 May 2007
Testing challenges with LTE
How to optimize radio interface?
No radio measurement data available since no ”Iub-like” interface
Increased complexity of eNB
need for analysis of internal traffic
need for internal debugging
need for analysis of protocol data
How to test inter-eNB handovers?
How to test inter-system handovers?
How to test voice and video broadcast?
10x higher throughput  How to verify eNB performance?
How to test application level QoS? How to verify SLA?
How to handle network management challenges?

21. LTE standardisation status
3 May 2007
LTE standardisation status
Specification work done by 3GPP TS RAN.
First 3GPP specs expected 3Q2007
First trials expected 2008
Commercial release expected 2009
NetHawk is member in 3GPP and follows closely the standardisation work
Commercial
Release
Specification
Trials
First 3GPP specs expected 3Q/2007

22. 3 May 2007