Edge002

EPFL
Cours “Mobile Networks”

GPRS & EDGE
« First steps toward Wireless
data »

Frédéric Michaud
Network Development
Engineering
14/12/2004

GPRS Part 1
Content

From Theory…
From Theory…

11- -INTRODUCTION
INTRODUCTION

22- -SERVICES
SERVICES

33- -ARCHITECTURE
ARCHITECTURE

44- -MOBILITY MANAGEMENT
MOBILITY MANAGEMENT

55- -SESSION MANAGEMENT
SESSION MANAGEMENT

66- -TRANSMISSION ON BSS NETWORK
TRANSMISSION ON BSS NETWORK

77- -RADIO RESOURCE MANAGEMENT
RADIO RESOURCE MANAGEMENT

Frederic Michaud 14.12.04 EPFL – cours “Mobile network” 2

Introduction

General Packet Radio Service:
a way to extend packet transfer up to the mobile station

GSM
GSM GPRS
GPRS

– Circuit Switch –– Packet Switch architecture
Packet Switch architecture
– Circuit Switch
architecture
architecture –– End to End IP service (mobile
End to End IP service (mobile
– Indirect access to IP = IP host)
= IP host)
– Indirect access to IP
network
network –– Re-use BSS architecture
Re-use BSS architecture
– Too sensitive
– Too sensitive –– New core architecture
New core architecture
connection for data
connection for data –– Max theoretical rates ~170
Max theoretical rates ~170
(today)
(today) kbps
kbps
– Expensive solution for
– Expensive solution for
data network (HSCSD)
data network (HSCSD)

Services
BANKING & FINAN- LOCAL SERVICES Special
NEWS BUY & SELL TRAVEL
CIAL SERVICES (CITY GUIDE) Interest
General Headlines Stock indexes Taxi Classifieds Traffic (traffic jams, Mobile telephones
Financial & Business Stock prices Restaurants - Cars radar, control,…) Internet sites and
Politics Metal prices Cinema - Properties Public transportation services
Tabloids Stock alert Theatres - Jobs Navigation services Computers and
Culture & Currency rates Concerts Auctions Train schedules hardware
Entertainment Interest rates Exhibitions Shopping Flight schedules Automobile
INFOR- Sports Account balance Night Clubs - Small daily Hotels
Lottery Credit/debit balance Emergency services items Holiday packages
MATION Cheque balance Pharmacies - Specific
Money transfers Household promotions
Bill payments assistance Tickets
Automatic call Weather
Account status flash Time
Stock purchase Directory services
Financial products ATM Locator
purchase

SMS E-MAIL FAX BULLETIN BOARDS
COMMU- Groups with common
Send/receive SMS messages Send/receive e-mails Send/receive fax
NICATION SMS to postcard E-mail to voice (IVR) Special features (delivery and receipt interest
report, storage for later delivery) Messages, News, etc

ORGANIZERS PERSONAL ASSISTANT TOOLS MISCELLANEOUS FAMILY
PRODUC- To do lists Reminders Call management Calculator Activating domestic Family VPN
TIVITY Calendar Correspondence management Dictionary appliances Synchronised
Address book Voice to SMS, E-mail and fax Translator Paying at vending machines
Agenda Translation services Currency converter Identity verification

ASTROLO-
MUSIC TV LIFESTYLE FUN CHATS PICTURES GAMES DATING
GY
ENTER- Ringtones Program- Gastronomy Jokes Topic Icons Puzzles Horoscopes Chats
TAINTMENT Short clips me Hobbies Sayings specific Logos Quizzes Astrolove Dating
(e.g. MP3) schedules Fashion Dream Private Photos “Tamagotchi” Biorhythm services
Highlights Parties analysis Postcards Games Specific
Gambling/Betting Horoscopes


Services
Notion of QoS

QoS = Quality of Service
5 Classes as specified in ETSI
– Service Precedence / Priority
– Delay
– Mean Throughput
– Peak Througput
– Reliability

FTP (NRT): Video Streaming (RT):
– Service: minor – Service: medium
– Delay: < 7 sec (most likely Best effort) – Delay: < 7 sec (most likely Best effort)
– Mean throughput: 4.4 kbps – Mean throughput: 44 kbps
– Peak throughput: N/A – Peak throughput: 64 kbps
– Reliability: high to medium redundancy – Reliability: medium to low (UDP protocol)

Architecture
Network Diagram

NSS ISP - External
HLR GPRS Core Network Network
MSC/VLR
Gc
Gr Gi
Gs
SGSN DNS GGSN

A Gn Gn
BSS

GPRS
Gb IP Backbone
Gn
Transcoder Gn
Ater
Charging Border
Gateway Gateway

Um Gp
BSC Abis

Inter PLMN
Backbone
BTS

Architecture
New interfaces

Interface elements Main usage Protocol type

Um MS – BTS Radio interface RLC/MAC

Abis BTS – BSC Standard GSM if. RLC/MAC

Gb BSC – SGSN GPRS data LLC/FR

Gc GGSN – HLR HLR queries for PDP context (IP)/SS7
activation

Gd SGSN – SMS GMSC Short Messages exchange SS7

Gf SGSN – EIR Terminal identity check SS7

Gi GGSN – Data Network Data transfer IP

Gn SGSN – SGSN Mobility management IP

SGSN - GGSN PDP context activation
Data transfer
Gp BG – BG Inter-operator link IP

Gr SGSN – HLR Location management SS7

Gs SGSN – MSC/VLR GSM/GPRS mobility Management SS7


Architecture
evolution of BSS network

New hardware in BSS: Packet Controlling Unit (PCU)
– can be compared to TRAU function in GSM
– generally located in the BSC
– heart of the packet transmission in BSS network
– allow the dynamic traffic allocation
– Provide the radio resource management mechanism, adapted to packet
BTS transfer
RLC
RLC
RLC PCU
SGSN
buffer
RLC RLC RLC LLC LLC LLC
buffer
RLC Gb
RLC buffer
RLC

Abis


Architecture
New core equipments
HLR VLR Charging Gateway

External
PCU External
IP world
IP world
GGSN

PCU IP network

SGSN
GGSN
• Packet routing (IP – BSS)
• Mobility Management • GPRS Tunneling (PLMN – internet)
• Session Management • Charging
• Charging • O&M (Operation & Maintenance)
• Cyphering and compression • Lawful interception

Other equipment:
Border Gateway, Charging Gateway, DNS, Firewalls


Architecture
GPRS Protocol stacks

BSS elements manage everything related to radio resource,
mobility and session management

Um Gb Gn Gi
Applica
Data traffic tion
IP / IP /
X.25 X.25
GMM/SM Relay
Mobility Management SNDCP SNDCP GTP GTP
Session Management
cyphering UDP / UDP /
LLC Relay
LLC TCP TCP

RLC RLC BSSGP BSSGP IP IP
Network Network L2 L2
MAC MAC Service Service
Radio Resource Management GSM RF GSM RF L1bis L1bis L1 L1
(TBF allocation, user/timeslot
multiplexing, etc..) MS BSS SGSN GGSN

PS/CS paging


Architecture
Gb interface
Open interface between the BSC and the SGSN. Consist of three layers:
– Frame Relay: link layer access between peer entities via a Bearer Channel.

– Network Service: set of virtual connections responsible for data transmission, congestion control, load
sharing between Network Service Entities.

– BSSGP: Virtual Connection management, paging support, flow control support.

NS-VC DLCI Data Link Connection Identifier (FR
BVC 0 address) NS-VC BVC 0
for for
signalling FR Bearer Channel signalling
NSE Physical Link (= pcm-tsl) NSE
(=PCU )
Own BVC Own BVC
for for
each BTS each BTS
NS-VC DLCI Data Link Connection Identifier (FR NS-VC
address)
Load Sharing FR Bearer Channel
Physical Link (= pcm-tsl)
BSC SGSN

BVC = BSSGP Virtual Connection
BSSGP = Base Station Subsystem GPRS Protocol
NSE = Network Service Entity
NS-VC = Network Service Virtual Connection
FR = Frame Relay

Gb interface will move on IP protocol

Mobile equipment

Three types of Mobile Classes

CLASS A: « Rolls Royce » CS Core Network (GSM)

Simultaneous CS/PS Paging
Simultaneous CS/PS data transfer

PS Core Network (GPRS)

CLASS B: « Standard » CS Core Network (GSM)

Simultaneous CS/PS Paging
CS call or PS data transfer


CLASS C: « Cheap » CS Core Network (GSM)

CS mode (GSM only) or PS mode (GPRS only)


Mobility Management
Mobile States

IDLE
– not attached to GPRS
– MS is not reachable
IDLE

GPRS Attach GPRS Detach READY
– MS known down to Cell by SGSN
STANBY
timer READY – May receive/transmit packets
expiry – No Packet paging required
READY timer expiry
PDU Transmission – MS remains in READY state until “READY
Force to STANBY
Timer” expires or GPRS Detach

STANDBY
STANDBY
– MS known down to Routing Area by SGSN
– MS attached to GPRS
– May receive Packet paging
– No data reception or transmission

Mobility Management
Temporary identity

Notion of P-TMSI (Packet Temporary Mobile Subs Identifier)

– Temporary identifier to differentiate a mobile in a SGSN
– associated to a ciphered signature
– P-TMSI+ signature transferred at each location update

Notion of TLLI (Temporary Logical Link Identifier)

used between MS and SGSN before attachment
randomly selected by MS when uplink request (risk of collision)
after attach : TLLI=P-TMSI
used to identify MS on the air interface

IMSI is never transferred


Mobility Management
Paging enhancement with GPRS

Network Mode I Network Mode II
HLR HLR

MSC/VLR Gr MSC/VLR Gr
SGSN SGSN
Location update
Gs

CS paging or SMS

A Gb A Gb
CS paging or SMS

BSC BSC
Paging message on: Paging message on:
Abis Paging channel Abis Paging channel only
Packet data channel


Mobility Management
GPRS Attach

SMSC

BSC MSC/VLR HLR

3
2 4
5
DNS
1 Charging
2 SGSN
Gateway
6
GPRS handset
7
GPRS

1. GPRS Attach Request IP Backbone

2. Authentication Border
GGSN
Gateway
3. Update Location (GPRS)
4. Insert Subscriber Data
5. Location Update (GSM) Inter PLMN
Backbone
ISP
External Network

6. GPRS Attach Accept
7. Attach complete


Mobility Management
Routing Area Update

DNS
BSC SGSN1
GPRS handset

GPRS
5 4 3 2
IP Backbone

BSC SGSN2 GGSN
GPRS handset

1 6
8 7

1. RA Update Request (old RAI)
2. DNS Query: IP @ for old RAI
3. SGSN Context Request
4. SGSN Context Response
5. Forward Packets
6. Update PDP Context Request: IP @ of new RAI
7. Update PDP Context Response
8. RA Update Accept

Session Management
Notion of PDP context

Packet Data Protocol context:
– set of information stored in mobile, SGSN and GGSN
– allow packet data transfer between a certain type of network and the mobile

PDP context contains:
Main Field Description

type of PDP network IP, X25 ….

Mobile address IP address or X.121 address for X25 network

SGSN address IP address of the serving SGSN

NSAPI Network Service Access Point

QoS Profile Quality of service negociated for this PDP context

Access Point Name APN (service) requested by the mobile (ie WAP, internet…)


Session Management
PDP Context Activation

SMSC

BSC MSC/VLR HLR

2 DNS
1 Charging
SGSN
Gateway
5
GPRS handset

GPRS
IP Backbone
3

1. Activate PDP Context Req Border
GGSN
Gateway 4
2. DNS Query
3. Create PDP Context Req
4. Create PDP Context Rsp Inter PLMN
Backbone
ISP
External Network

5. Activate PDP Context Ack


Session Management
Data Transfer

SMSC

BSC MSC/VLR HLR

DNS
Charging
SNDCP IP SGSN
Gateway
GPRS handset

IP GPRS
S-CDR G-CDR
IP Backbone

Border
GGSN
Gateway GTP IP

IP
IP@ src IP@ dst Inter PLMN
Backbone
ISP
External Network

Mobile Server
SGSN GGSN


Radio Resource Management
RLC/MAC layer

RLC/MAC is the most important layer for communication between MS and
BSC:
– RLC/MAC controls the data flow over the air interface and Abis interface.
– BSS performance are based on RLC block transmissions / retransmission
– RLC: Provide controlling function (ack/unack mode)
– MAC: Medium Access mode: allows to have dynamic allocation of Mobiles over radio
timeslots (pair ofInformation field
LLC frame FH TBF/USF) FCS

LLC layer

RLC
BH Info field BCS BH Info field BCS BH Info field BCS
blocks
Primary Following
RLC/MAC layer
block block

Normal burst Normal burst Normal burst Normal burst Physical layer

FH = Frame Header
FCS = Frame Check Sequence
BH = Block Header
BCS= Block Check Sequence
(When SDCCH coding is used, BCS corresponds to the Fire code)

Notion of GPRS territory

GSM
TRX 1 CCCH TCH TCH TCH TCH
Territory

GPRS
TRX 2 TCH
Territory

Default Dedicated
GPRS GPRS
Capacity Capacity
Territory border move based
On GSM and GPRS traffic load evolution


Physical Layer

TDMA frame=4,615 ms

01 2 3 4 5 6 7 01 2 3 4 5 6 7 01 2 3 4 5 6 7 01 2 3 4 5 6 7

1 GPRS multiframe = 52 TDMA frame=240 ms

Block 0 Block 1 Block 2 T Block 3 Block 4 Block 5 i Block 6 Block 7 Block 8 i Block 9 Block 10 Block 11 i
0 4 8 13 17 21 26 30 34 39 43 47 51
12 blocks of 4 radio burst each

Each block can transfer one GPRS logical channel information


Logical Signalling for GPRS

GPRS Air Interface Logical Channels

CCH
DCH
Common Channels
Dedicated Channels

PCCCH
BCH Packet Common Control
Broadcast Channels Channels
DOWNLINK ONLY (can be combined with CCCH)

PBCCH
Packet Broadcast Control CH
(can be combined with BCCH)

MS CONTINUOUSLY
MONITORS PPCH PAGCH PRACH
Packet Paging CH Packet Access Grant CH Packet Random Access CH
GPRS: DCH
BSS WANTS TO PDCH IS MS ASKS FOR 'Dedicated' Channels
CONTACT MS ALLOCATED TO MS PDCHs.

DCCH
Dedicated Control TCH
Channels Traffic Channels

PTCCH
Packet Timing Control Channel.
PACCH
Packet Associated Control CH PDTCH
Allocated to the opposite direction than the PDTCH Packet Data TCH, one channel can be shared
to which it is associated. by several active users.


Timeslot sharing

GPRS data transfer = discontinuous series of Temporary Block Flows.
– 1 TBF = 1 user (with a given TFI, TLLI, USF)
– 1 TBF can be transferred onto several radio timeslots
TBF4

TBF3 TBF2 TBF2
TBF3 TBF1 TBF1 TBF1

TSL 0 TSL 1 TSL 2 TSL 3 TSL 4 TSL 5 TSL 6 TSL 7
BCCH TCH TCH TCH PDCH PDCH PDCH PDCH

TDMA frame

Data transfer = Uplink / Downlink TBF (Temporary Block Flow) Assignment
– Timeslots allocation GSM CCCH channels (RACH - AGCH - PCH) (GPRS - phase 1)
– GPRS phase 2: dedicated common control channels (PBCCH/PCCCH)


Notion of Data flow

RLC layer create a Temporary Block Flow, each time data needs to be sent

Downlink TFI=14 TFI=14 TFI=14 TFI=14 TFI=14 TFI=14 TFI=14
Data transfer
BSN=24 BSN=25 BSN=26 BSN=27 BSN=28 BSN=24 BSN=26
RLC header

0 4 8 13 17 21 26 30 34 39 43 47 51
TFI=14 TFI=14

Ack:
Ack:
25,27,28
24,26
Uplink Nack:
MS receive on 24,26
TFI 14

TBF dynamically managed by the network
To avoid collisions, network identify each user with TFI and TLLI
Number of retransmission linked to C/I ratio
Retransmissions will decrease real user data throughput


Multi user radio sharing

MAC layer handle resource sharing between mobiles

Downlink SP=0 SP=0 SP=1 SP=1 SP=1 SP=1 TFI=14
Data transfer RRBP= RRBP= RRBP= RRBP= RRBP=
MAC header i+4 i+3 i+2 i+2 i+1

0 4 8 13 17 21 26 30 34 39 43 47 51
TFI=14 TFI=14

Ack:
Ack:
25,27,28
24,26
MS receive Nack:
on TFI 14 24,26

Mobile knows on which block to ack/nack received PDU
Mobile use these control blocks to transfer other information (measurement reports, uplink resource request, etc…)


Dynamic uplink sharing

Several mobiles can share the same radio timeslot
MAC layer indicates each mobile which block it can use for uplink transfer

Downlink
Data transfer USF=4 USF=4 USF=1 USF=5 USF=5 USF=4 USF=1 USF=1 USF=5
MAC header

0 4 8 13 17 21 26 30 34 39 43 47 51

Block 3 Block 7 Block 8
MS USF 1

MS USF 4

MS USF 5

Uplink State Flag definition only local to a physical channel (i.e. 1 radio timeslot in the TDMA frame)


GPRS Part 2
Content

… to practice
… to practice

IMPLEMENTATION CONSTRAINTS
IMPLEMENTATION CONSTRAINTS

NETWORK DIMENSIONING & PLANNING
NETWORK DIMENSIONING & PLANNING

NETWORK PERFORMANCE
NETWORK PERFORMANCE

ANALYSIS AND OPTIMISATION
ANALYSIS AND OPTIMISATION

TOOLS FOR GPRS
TOOLS FOR GPRS


Implementation Constraints
Upgrade of GSM network

New Core Network
– GPRS backbone is an IP network
– New approach in Mobile Telecommunication
– First interaction between IT and mobile telecom network dept.

Multi-supplier solution
– Interoperability problems
– Interface Gb, Gs, Gr are standardised by ETSI but multi-vendor solution
always leads to complexity.
– Mobile and network compatibility over the air interface is another source
of problems
– Different mobiles = different performances


Hardware & Software Releases

HW & SW Release management
– Network is often heterogeneous
– Different generation of base stations, BSC and MSC
– Software Releases are delivered at different times

Incomplete GPRS features
– QoS not fully implemented
– Radio enhancement (PBCCH) not fully implemented

immature ETSI specifications
– Suppliers follow different versions


Heterogeneous BSS Network

GPRS Core
Network

South region - BSS Network North region - BSS Network
Supplier A Supplier B

GPRS handset

GPRS handset

Problem of uniform Quality of Service (different SW/HW, different problems)
Complex network evolution (i.e. new feature cannot be implemented country wide)


Handsets & Services

Limitation in mutlislot & coding scheme capability:
– First handsets: 2+1 (i.e. 2 TSL DL / 1 TSL UL)
24 kbps DL / 12 kbps UL
– Current handsets: 4+1
48 kbps DL / 12 kbps UL

ETSI specifications problems
– Lots of change request
– PBCCH not supported by network and first GPRS mobiles

Poor content for GPRS Services
– Lack of «adapted» phones
– Lack of «killer» applications

GPRS Dimensioning

Number of GPRS users
Paquet transfer per users
Quality of Service
Coverage area
Network Radio
Peak hours
Dimensioning Dimensioning

Transmission capacity GPRS Territory size
(Abis/Gb) Number of cells
Bearer size TRX upgrade
Number of PCU Signalling increase

New hardware requirements
New hardware requirements

Network Planning

Reuse existing GSM coverage
Reuse of GSM signalling and traffic plan
New core network planning
New Routing Area Planning


Network Performance
Radio constraints

Cell reselections
– GPRS phase 1:
– Network doesn’t control cell re-selection process
– Based on GSM cell re-selection of MS in idle mode
Risk of ping-pong effect
Critical decrease of user data throughput

C/I (carrier/interference) criteria
– GPRS is very sensible to interferences
Data throughput drops quickly with interferences

Capacity
– GSM traffic has priority over GPRS
– « Best effort » mode
Low throughput in peak hours

Analysis and optimisation

Performance Analysis – Access to Network resource

1123
32.15%
298

81.88%

57.26%



Performance Analysis – Session success

13%
2446
45.4%

623 87%
53.3%


Tools for GPRS

Protocol analyser
» In depth signalling study


Tools for GPRS

Probe System
» Data capture across all GPRS network interfaces

MSC VLR HLR

Gr
Gs Gc

Gi internet
internet
Gb Gn
BTS BSC SGSN GGSN
Gp

Foreign
Foreign
BG PLNM
PLNM

1. Data capture 2. Data data storage 3. Data analysis


Benefit of Gb analysis

Full network supervision
Access to QoS information
Information that can be shared accross mainy actors:
– Radio optimisation team
– Maintenance team
– Quality team
– Traffic team
High level of detail
– Info per session
– Info per user
– Info per cell/PCU
– Info per network area


Documentation

Réseaux GSM (ISBN 2-7462-0153-4)
Xavier Lagrange, Philippe Godlewski, Sami Tabbane

Ingénierie des réseaux cellulaires (ISBN 2-7462-0550-5)
Sami Tabbane

The GSM Evolution - Mobile Packet Data Services (ISBN 0-470-84855-3)
Peter Stuckmann

GPRS Signalling & Protocol Analysis – Vol. 1
Gunnar Heine

Evolution towards EDGE
Content

DEFINITION
DEFINITION

NETWORK PERFORMANCE
NETWORK PERFORMANCE

EDGE IMPLEMENTATION
EDGE IMPLEMENTATION

EDGE DIMENSIONING
EDGE DIMENSIONING

APPLICATIONS FOR EDGE
APPLICATIONS FOR EDGE


EDGE – evolution of GSM air interface
8PSK modulation to replace GMSK

(0,0,0) (0,1,0)
(0,1,1)
(0,0,1) (1,1,1)

(1,0,1) (1,1,0)
(1,0,0)

EDGE GSM
Modulation 8-PSK, 3bit/sym GMSK, 1 bit/sym
Symbol rate 270.833 ksps 270.833 ksps
Payload/burst 346 bits 114 bits
Gross rate/time slot 69.2 kbps 22.8 kbps


From GSM to GERAN
evolution of specifications

2G 2.5G 2.75G 3G

3GPP
(GERAN)
GSM GPRS

EDGE GERAN
ETSI
(BSS)

UMTS/UTRAN
3GPP
(UTRAN)


EDGE as a GERAN feature

Enhanced Data rates for Global Evolution, from Release 99
Technical aspects Performances

EDGE is a mature product (all vendors 2 to 4 times higher data throughput than GPRS
NEs & features are ready since mid’2004)
Interactive and Background classes*, Rel 99: Now
EGPRS only (ECSD not implemented by Web browsing, mail attachment, chat, e-
suppliers) commerce, file transfer,… at high data rate.
Available for all bands 2005
Streaming with mobility QoS*, Rel 4:
(850/900/1800/1900)
Audio & Video streaming
2006/2007
Ensure the backward compatibility with Video on-demand.
GPRS mobiles
Conversational for data services*, Rel 5 & Rel 6:
Videotelephony
(*) EDGE has been standardised to enhance the data rate but not to enhance QoS service (
still best effort service) other features of GERAN will do it

Objective: a higher data throughput thanks to a better spectral efficiency.

Theoretical performance of EDGE

kbps
60 EGPRS (8-PSK)
EGPRS (GMSK)
50 GPRS (GMSK)

40

30

20

10

0
CS-1 CS-2 CS-3 CS-4 MCS-9 MCS-8 MCS-7 MCS-6 MCS-5 MCS-4 MCS-3 MCS-2 MCS-1

EDGE can provide data services with maximum radio
throughput of 235kbps using 4 TS.


Network impact of EDGE implementation

New BSC Release
P A GMSC
2106
B ABIS C MSC/
T U BSC
BSC MSC HLR
HLR
BTS VLR
S
B Gb Gs Gr
B
T
T
S
S
Gi (IP)
SGSN GGSN
GGSN
Um BTS SGSN

AUC Upgrade Gn Gn PDN

mobiles
IP-Backbone
Other PLMN
EIR Network
HW or SW Upgrade

No Upgrade
Gp
New Mobiles

Radio performances impact of EDGE implementation

EDGE is main influence on GSM is on the radio interface.

Upgrade of GSM network with EDGE will influence the radio
conditions
There is a need for carefull radio optimisation

EDGE throughput is highly dependent on interferences (C/I),
especially at the cells’ border


EDGE vs UMTS for indoor coverage

Robustness of Edge :
– Compensation of radio propagation fluctuation thanks to Link Adaptation

Instability of UMTS :
– Throughput Drop due to building penetration and the mobile « Power rise »
phenomenon.
Throughput (kbps)

Power limitation
320 UMTS

200 EDGE 900 Link adaptation

BTS-MS distance (m)

500 1200


Dimensioning principles: radio

Deploy EDGE on BCCH TRX (beacon channel) or not?
Preferred
configuration C/I mostly > 15dB For all values of C/I

Choose the TRX that have the best C/I distribution

If BCCH and non BCCH TRX have same C/I distribution
try to optimize the network to increase the C/I.
Small PS traffic BCCH
If BCCH and non BCCH TRX have always slightly the same
(1 to 5 TS) C/I distribution
put EDGE on non BCCH with synthesized SFH
(EDGE performances could not reach expected values, i.e.
average of 30kbps/TS)

Try to optimize the network to increase the C/I of non
BCCH TRX.

Important PS traffic If non BCCH TRX have always slightly the same C/I
non BCCH distribution, put EDGE on non BCCH with synthesized
(more than 5 TS)
SFH
EDGE performances could not reach expected values
(i.e. average of 30kbps/TS)


Dimensioning principles: transmission

Objective: a higher data throughput thanks to a better spectral efficiency.
More capacity
needed in interfaces
SGSN
BTS
GGSN
Gr
Abis Gb
EDGE BSC
TRX

GSM/GPRS/EDGE
Network

Abis
A Internet
BTS BSC
EDGE
TRX
MSC EDGE functionality
Abis
in network elements

BTS
EDGE EDGE
handset TRX

EDGE capable TRX need to be added, old BTS might have to be changed, BSC/PCU
shall support EDGE capability.
Re-dimensioning of the interface according to the traffic growth.

Dynamic Abis principle

PCM transmission frames = permanent time slots for the CS traffic and signalling
+ Dynamic Abis Pool for the data (DAP)

common for multiple Pool
Dynamic Abis
GSM/EDGE TRXs located
under the same BTS.


… and services evolution

New services…
Broadband video
Digital video

Location services Videotelephony
Other killer app.?
Videostreaming, ftp (big files)

2004 R’99 2005 Release 4 2006 Release 5 2007 Release 6 2008 Release 7

…and major performances & QoS enhancements to support it.
ECSD: EDGE for CS
(not yet adopted)
SAIC:
Increase spectral efficiency
NACC:
Reduce cell reselection
Delayed TBF release:
Reduce GPRS delays
DTM: FLO:
Simultaneous CS+PS Conversational PS, multiservice
PFC: Generic access A/Gb:
QoS service differentiation Technology convergence


EDGE Status Worldwide

Edge is a GSM - BSS feature to enable highest data throughput (proven
technology)
38 devices are currently Edge compatible
GSM Wireless Industry entirely committed to Edge
111 networks deploying Edge currently
35 commercially available Edge networks


Continuity of Service

Without EDGE With EDGE

Data Speed
Data Speed
384kbps 384kbps Service Continuity
with reduced
UMTS No Service UMTS throughput and latency
Continuity
200kbps

Edge Underlay
40kbps GPRS legacy 40kbps GPRS legacy

Edge Introduction -> Bridging the
Broadband Services gap

EDGE Service Portfolio

Services FTP RTT GPRS EDGE UMTS
(kbps) (sec)

Best N/A
• MMS
Effort
• Orange World >16 1-5

• Audio/Video <1
>128
Streaming
• Video >64 N/A
Messaging
• File 64-384 N/A
Downloads
• Video
>64 <0.2
Telephony
Not possible Enabler technology
Best Fitted technology Premium technology

HSDPA as the next evolution after EDGE

HSDPA is to UMTS what EDGE is to GPRS
– New radio modulation offering higher bandwidth

Data Speed
2Mbps UMTS to HSDPA is a factor 5
HSDPA
x5 EDGE to UMTS is a factor 2
GPRS to EDGE is a factor 5
384kbps
UMTS
x2
200kbps
EDGE
x5
40kbps GPRS


Access Network Logical Layers

GSM (EDGE) WAN UMTS (HSDPA)

MAN Wi-MAX

LAN Wi-Fi
Bluetooth
PAN
UWB


Mobile Broadband Technology map

IP Based Convergence IP Core

Wi-Max Wi-Max
802.16d 802.16e Backhaul
Wi-Fi
802.11

In-Building
Rural Sub-Urban Urban
Hotspots PICO Access
MACRO MICRO

Cellular Mobility
GSM (EDGE) & UMTS (HSDPA)

Conclusion

EDGE deemed as a mature/stable/robust technology-
– Edge as a key technology for in building coverage
– Edge terminals are cheaper and more robust than UMTS (batteries…)
– Complementary to UMTS in rural and suburban areas
– International roaming with American/Asian operators that will transit to EDGE
in Europe

For usual radio conditions:
– RLC throughputs around 40 kbps may be expected per timeslot (x4 for class
10 MS)
– FTP throughputs around 35 kbps may be expected per timeslot (x4 for class
10 MS)

This performance greatly depends on
– The link adaptation algorithm of the manufacturer and parameter settings
– The engineering solution chosen for EGPRS implementation


Edge002

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