GSM Systems Division
Andrew J Wilton
Director of Applied Research
GSM Systems Division
GSM Systems Division
Agenda
AGENDA
Why Packet?
GSM/GPRS Architecture
What is EDGE?
Deployment Issues
Standards
Terminal Classes
GPRS Applications
GSM Systems Division
AGENDA
Why Packet?
GSM/GPRS Architecture
What is EDGE?
Deployment Issues
Terminal Classes
Standards
GPRS Applications
Why Packet?
Why Packet
GSM Systems Division
Bursty Services
Circuit Data Utilisation
bit/s
Circuit
Capacity
33.6k
Capacity (Mbytes)
WWW
pages
USED
AVAILABLE*
% USED
Email
(Download)
0.99
9.7
10.2
Email
0.06
3.0
2.0
0.23
4.2
5.5
t
Mean
WWW browsing example
(Browsing)
• Many user actions are bursty
e.g. browsing WWW pages
• Internet has variable delays
• PSTN channel not used 100%
Web
(browsing)
* 56.6 Kbits/s
Why
Permanent
Virtual
Permanent
Virtual
Circuits
Circuits?
GSM Systems Division
Email via GSM
User
Modem
GSM
Modem
PSTN
Auth.
Server Email
Server
Internet
Email via GPRS
User
GPRS
Virtual GPRS
Data Tunnel
INITIAL CALL PROCESS
•
•
•
•
GSM Call
TrainModem
Login and Authenticate
Download mail
Total
Internet
Authenticated path
to Email server
TIME (s)
INITIAL CALL PROCESS
TIME (s)
4
30
11
180
• GPRS Call
• Login and Authenticate
• Download mail
4
11
180
3 min 45s
SUBSEQUENT CALL
• Repeat Above
Auth.
Server Email
Server
Total
3 min 15s
SUBSEQUENT CALL
3 min 45s
Mail Only When Connected
• Not applicable - Virtual Cct
0min
0s
Mail Continuously Downloaded
GSM Systems Division
GPRS - the Low Cost Data Upgrade
Upgrade
to
Data
Saturated Voice Cell
- 1 Carrier
- 150 subscribers
Saturated Voice Cell
+ 15% Subs are Data Users
@ 56kbit/s
New Timeslots Required 1
Penetration
GPRS
HSCSD
3%
0
5*-12
15%
0
14*-21
1 Conditions:
Voice
- 20mE
- 1% blocking
Data
- 1:10 duty cycle
- 15 minute sessions
* lower figure is data only
- 1 session/ 4 hours
~ 10 mins worst case delay
GSM Systems Division
Agenda
AGENDA
Why Packet?
GSM/GPRS Architecture
What is EDGE?
Deployment Issues
Standards
Terminal Classes
GPRS Applications
GSM Architecture
GSM Systems Division
GMSC
PSTN
A-bis
BTS
‘A’
BSC
MSC
MAP
GPRS
Register
H/VLR
HLR/AUC
GPRS
Register
GSM Systems Division
Architecture - GSM with GPRS
GMSC
PSTN
Circuit
Switched
Traffic
A-bis
BTS
‘A’
MSC
MAP
Peer
Elements
BSC
GPRS
Register
H/VLR
PCU
Gb
Packet
Traffic
HLR/AUC
GPRS
Register
MAP
SGSN
Public Switched
Packet Network
Gn
GGSN
Gi
What IS an SGSN/GGSN
GSM Systems Division
Mobililty Management
Session Management
- QoS
- Security
- Attach/Detach
HLR
MAP
Signalling
(GGSN)
External Data Domain
MAP
Signalling
(SGSN)
BSS
PCU
BSS
PCU
SGSN
Routeing
info
Client
BSS
PCU
Internet
Intranet
GGSN
SGSN
BSS
PCU
Client
BSS
PCU
- Routing
- Signalling
- Resource Mgt.
Servers
GSM Systems Division
The Packet Control Unit (PCU)
BTS
BSC
GSN
Abis
Gb
PCU
GPRS
Function
CCU
MAC
RLC
Packet
Switching
RLC
MAC
–Segmentation/Re-assembly
–ARQ
–Multiplexing (different mobiles)
–Contention resolution (u/l) - QOS related
–Scheduling/queueing (d/l) - QOS related
GSM Systems Division
Agenda
AGENDA
Why Packet?
GSM/GPRS Architecture
What is EDGE?
Deployment Issues
Standards
Terminal Classes
GPRS Applications
GSM Systems Division
Coding Rates for GPRS & EDGE
GPRS
Rate
Code Rate
9.05kb/s
0.5
13.4kb/s
0.66
15.6kb/s
0.75
21.4kb/s
1.0
CS1
CS2
CS3
CS4
GMSK (1 bit/s/symbol)
EDGE
MCS1
MCS2
MCS3
MCS4
Rate
8.8 kb/s
11.2 kb/s
14.8 kb/s
17.6 kb/s
Code Rate
0.53
0.66
0.80
1.00
GMSK (1 bit/s/symbol)
EDGE - Key Aspects
• A new modulation Scheme
- 8PSK
• 200 KHz Channel spacing
- unchanged
EDGE = GMSK + PSK
MCS5
MCS6
MCS7
MCS8
8-PSK (3 bit/s/symbol)
Rate
22.4 kb/s
29.6 kb/s
44.8 kb/s
59.2 kb/s
Code Rate
0.37
0.49
0.76
1.00
• Symbol rate unchanged
- 270k symbol/s
BUT
- 3 bits/symbol
EDGE - Coverage vs Data Rate
GSM Systems Division
Shannon’s Law
EDGE Coverage Relative to Speech 1,2
( )
C log
S
1+
=
2
I
B
% Cell Area Covered
100
80
60
• Higher Date Rate Requires
- More RF Bandwidth
40
20
0
8.8
11.2
- More C/I
• For EDGE additional C/I
- 7 - 10 dB
14.8
17.6
22.4
29.6
44.8
Data Rate / Time Slot
1
Interference Limited Case
2
Conditions:
•
•
•
•
Speech Coverage 12dB C/I
4/12 Re-use
No SFH
10 % Block Erasure Rate
59.2
GSM Systems Division
Path
Standards
GSM
Now
Evolution Paths for GSM
Delay
Equipment
Spectrum
B/W
Now
x4
Q1 ‘99
x4
EDGE 1
Q1 ‘00
x20
UMTS*
Q1 ‘00
x40
HSCSD 1
GPRS 1
* Whole Carrier
1 4 time Slots
Coverage
2 Interference Ltd
2
GSM Systems Division
Agenda
AGENDA
Why Packet?
GSM/GPRS Architecture
What is EDGE?
Deployment Issues
Standards
Terminal Classes
GPRS Applications
Effect of ARQ
GSM Systems Division
100
No Retransmission
80
60
One Retransmission
40
Two Retransmissions
20
0
8.8
11.2
14.8
17.6
22.4
(kb/s)
29.6
44.8
• Assumes 4/12 reuse and speech coverage at 12 dB C/I (no SFH)
59.2
Voice Over IP
GSM Systems Division
PSTN
Cost
PPDN
GMSC
Bandwidth vs Delay
GGSN
Voice
packets
lost
Data in
spare
voice
B/W
bit/s
Capacity
SGSN
MSC
Average
Voice
XCDR
t
Voice over
Packet
20 ms*
Voice over
Circuit
BSC
PC
U
x1
2 ms*
BTS
?
• Transmission
• MSC Costs
• Transcoders
Packet
Switch
?
• Transmission
• IP Routers
• Media Gateways
x10
• Over Dimension Transmission
- delay budget
• QoS Management
GSM Systems Division
The Service provider
IP Address
PSTN
PPDN
GMSC
GGSN
MSC
SGSN
Server
GPRS SERVICE IMPLEMENTATION
XCDR
GSM SERVICE IMPLEMENTATION
-
MSC based
Slow rollout (regression testing)
Service lost on roaming
New Service introduction
- potentially corrupts all services
- Tied to MSC vendor
- Client Server based
BSC
PC
U
BTS
- Very fast rollout
- Multiple sources for Application
development
- Each service is stand alone
- cannot corrupt others
- Matched to Web implementation
Phone (Client)
GSM Systems Division
GPRS- Opportunities for Competition
PPDN
PSTN
4
Server
Single MSC/
+ BSS Supplier
GMSC
1
4th Supplier
- Service Framework
GGSN
3
SGSN
MSC
3rd Supplier
- GPRS Core
Network
‘A’
XCDR
XCDR
BSC
BSC
BTS
BTS
2
2nd
Supplier
- BSS
Gb
Iu
PCU
RNC
5
NODE B
NODE B
UMTS RAN
5th Supplier
- UMTS RAN
GSM Systems Division
Islands of Coverage
UMTS
GSM
Server
Data
UMTS
UMTS
GPRS/EDGE
UMTS
Data
UMTS Service
CELLULAR COVERAGE
• Islands of UMTS coverage
- small cell size
- demand driven
• Wide area coverage
- GPRS or EDGE
• Dual mode UMTS/GSM handsets
CELLULAR SERVICE
• Services at edge of network
- transport via GSM or UMTS
• Service Transparent to Transport
- between operators
- between media (copper, mobile etc.,)
- A few services
- will run less well on GPRS/EDGE
GSM Systems Division
GPRS Threats and Opportunities
• Client/Server will be the Service Solution
- Speed of service deployment
- UMTS will require for cost effective deployment
- No disruption to speech service
• Opportunities for Competition
- No longer ‘tied’ to switch vendor
• UMTS Ready
- Re-use of GPRS core network
• Large number of Application Developers
- Competition
- Speed
• Service Re-use on UMTS
• Sell Service on Value not Cost
GSM Systems Division
Agenda
AGENDA
Why Packet?
GSM/GPRS Architecture
What is EDGE?
Deployment Issues
Standards
Terminal Classes
GPRS Applications
Standards Issues
GSM Systems Division
PPDN
PSTN
GMSC
GGSN
MSC
SGSN
Upgraded MSC
Network
Server
GPRS Core
Network
Gb
XCDR
Iu Interface
RNC
To GSM BSS
Iu
- One Logical Interface
- Two Physical Interfaces
NODE B
NODE B
UMTS RAN
GSM Systems Division
Agenda
AGENDA
Why Packet?
GSM/GPRS Architecture
What is EDGE?
Deployment Issues
Standards
Terminal Classes
GPRS Applications
GSM Systems Division
GPRS Terminal Types
Type A: Can support circuit and packet calls concurrently.
Type B:This type of phone can support circuit or packet (not
both together) and can be registered for both…i.e. an IP
address and a PSTN number.
Type C:This type of phone can only be registered for packet
OR circuit but not both.
GSM Systems Division
GPRS Terminal - Multi-Slot Classes
Multislot
class
COMPLEXITY FACTOR
Low
Medium
High
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
Maximum number of slots
Rx
1
2
2
3
2
3
3
4
3
4
4
4
3
4
5
6
7
8
6
6
6
6
6
8
8
8
8
8
8
Tx
1
1
2
1
2
2
3
1
2
2
3
4
3
4
5
6
7
8
2
3
4
4
6
2
3
4
4
6
8
Type
1
1
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
1
1
1
1
1
1
1
1
1
1
1
Tx and Rx
not
concurrent
Tx and Rx
Duplex
Tx and Rx
separate
frames
GSM Systems Division
Agenda
AGENDA
Why Packet?
GSM/GPRS Architecture
What is EDGE?
Deployment Issues
Standards
Terminal Classes
GPRS Applications
GSM Systems Division
E-Commerce -Key Enablers
• Dual Slot Phones
• SIM Toolkit
- some services now
• WAP,MExE
- full network interaction
- in the future
GSM Systems Division
E-commerce
E- Commerce
Over GPRS
Financial / Banking
Finance
Banking
On-line transactions
Clearing House
Application Providers
Retailers
Content
News
Weather
Sport
Loyalty Cards
Banking
Shopping
Promotions
Certificate Authority
Corporate / Operator
Applications
VPN
e-mail
Cost control
Intranet
Mobile
Transactions
Merchant
Transactions
Dual-slot mobile phones
(SIM Toolkit)
GSM Systems Division
GSM Systems Division
The End