This Presentation Gives Basics of GPRS and EDGE Network. With Brief Introduction to Advanced Ideas are shared in these slides.

1. ( E ) GPRS BASICS &
( E ) GPRS BASICS &
KNOWLEDGE SHARING
KNOWLEDGE
SHARING

2. (E)GPRS OBJECTIVES
“2G Data EXPLAIN”
Main topics
• Basic GSM/GPRS/EDGE data network functionality
Concepts
• (E)GPRS = GPRS & EDGE
• EGPRS = EDGE

3. (E)GPRS - Content
Functionality
• NE & interfaces
• Protocol stack
• TBF, Session Management, Mobility Management
Base Station Subsystem ( BSS )
•
Modulation (Air interface),
•
EDAP and PCU (Resource allocation)
•
Gb

4. SW and HW Releases
This material describes the Nokia (E)GPRS System
with the following SW and HW releases:
• BSS SW:
• BSS10.5, 11.0 and 11.5 and S12.0
• BSC variants with PCU1:
• BSCi, BSC2, BSC2i, BSC3i
• BTS versions:
• Talk, PrimeSite, MetroSite, UltraSite
• SGSN
• SG5.0

5. CONTENT :- 1
Introduction
• Network Architecture and Interfaces
• Mobile Classes
• Network Protocols
• Multiframe and Header Structure
• Air Interface Mapping – Physical and Logical Channel
Procedures
• State and Mobility Management
• GPRS Attach/Detach
• Routing Area
• Session Management (PDP context)
• Temporary Block Flow
•RLC/MAC Header
•TBF Establishment

6. GSM & (E)GPRS Network Architecture
Um
PSTN
Network
BSC
BTS
PC
U
HLR/AuC
EIR
MSC
Gb
EDAP
Border
Gateway
(BG)
Serving
GPRS
Support
Node
(SGSN)
SS7
Network
Corporate 1
Billing System
Router
PAP
U
GPRS
backbone
network
(IP based)
Server
Charging
Gateway (CG)
Local
Area
Network
Data
network
(Internet)
Corporate 2
Server
Lawful Interception
Gateway (LIG)
Inter-PLMN
network
GPRS
INFRASTRUCTU
RE
Gateway
GPRS
Support Node
(GGSN)
Router
Data
network
(Internet)

7. (E)GPRS Network Elements and Primary Functions
•
•
GGSN
• Session
Management
• GTP tunnelling
to other GSNs
• Secure
interfaces to
external
networks
• Charging &
statistics
• IP address
management
Domain Name Server
• Translates IP host names
to IP addresses (DNS
Resolution)
• Makes IP network
configuration easier
• In GPRS backbone SGSN
uses DNS to get GGSN and
SGSN IP addresses (APN
Resolution)
• Two DNS servers in the
backbone to provide
redundancy
Charging
Legal Interception Gateway
• Enables authorities to
Gateway
intercept subscriber data
• CDR
and signaling
consolidation
• Chasing criminal activity
• Forwarding CDR •
Operator personnel has
Enables GPRS
information to
very limited access to LI
billing center
roaming
functionality
Standard Nokia IP
• LI is required when
router family
launching the GPRS service
SGSN
• Mobility
Management
• Session
Management
• MS
Authentication
• Ciphering
• Interaction with
VLR/HLR
• Charging and
Border Gateway
• statistics
Interconnects
• GTP tunnelling to
different GPRS
operators'
other GSNs
backbones

8. GSM and (E)GPRS Interfaces
SMS-GMSC
SMS-IWMSC
E
SM-SC
C
Gd
HLR
MSC/VLR
D
Gs
A
Gb
TE
MT
R
BSS
Um
Gn
Gc
Gr
Gi
GGSN
SGSN
Gn
EIR
Gp
Gf
SGSN
GGSN
Other PLMN
Signaling Interface
Signaling and Data Transfer Interface
PDN
TE

9. (E)GPRS Interfaces
TE
R MT
Um BSS
E
MSC/VLR
A
D
HLR
SMS-GMSC
SMS-IWMSC
C
SM-SC
Optional
Gb
Gs
Gr
Gc
Gd
SGSN
Gn
SGSN
Gp
GGSN
Gf
EIR
LAN
SW / IP
BB
Gn
Gn
DNS
Ga
Gn
GGSN
Gn
CG
Other PLMN
Signaling Interface
Signaling and Data Transfer Interface
LIG
Gi
PDN
TE

10. GMSK & 8-PSK - Phase State Vectors
Envelope (amplitude)
Time
GMSK
(0,0,0)
Envelope (amplitude)
(0,1,0)
(0,1,1)
8PSK
(0,0,1)
(1,1,1)
(1,0,1)
(1,1,0)
(1,0,0)
22,5° offset to avoid zero
crossing
Time

11. 8-PSK Modulation
Phase states transitions
to avoid zero-crossing
(d(3k),d(3k+1),d(3k+2))=
(0,0,0)
3π/8
(0,1,0)
(0,1,1)
(0,0,1)
(1,1,1)
(1,1,0)
(1,0,0)
Gross rate/time slot
selected as the new modulation added
in EGPRS
• 3 bits per symbol
• 22.5° offset to avoid origin crossing
(called 3Π/8-8-PSK)
• Symbol rate and burst length identical to
those of GMSK
• Non-constant envelope ⇒ high
(1,0,1)
Modulation
Symbol rate
Bits/burst
• 8-PSK (Phase Shift Keying) has been
EDGE
8-PSK, 3bit/sym
270.833 ksps
348 bits
2*3*58
69.6 kbps
requirements for linearity of the power
amplifier
• Because of amplifier non-linearities, a 24 dB power decrease back-off (BO) is
typically needed, Nokia guaranteed a
BO of 2 DB for BTS
GSM + EDGE
GMSK, 1 bit/sym
270.833 ksps
114 bits
2*57
22.8 kbps

12. GMSK and 8PSK Bursts
dB
+4
+1
-1
-6
(**)
Phase state vector
diagram
•Amplitude is not fixed
•Origin is not crossed
•Overshooting
- 30
(***)
(147 bits)
(*)
10 µs
8 µs
10 µs
7056/13 (542.8)
µs
10 µs
8 µs
t
10 µs
GMSK Burst
dB
+4
+2,4
0
-2
-6
(***)
-20
(147 symbols)
-30
(**)
s
7056/13 (542,8)µ
(*)
10
8
10
2 2
22
10
8PSK Burst
8
10
s)
t (µ

13. 8-PSK Modulation – Back-off Value
• Since the amplitude is changing in 8-PSK the transmitter
non-linearities can be seen in the transmitted signal
• These non-linearities will cause e.g. errors in reception
and bandwidth spreading.
• In practice it is not possible to transmit 8-PSK signal
with the same power as in GMSK due to the signal must
remain in the linear part of the power amplifier
• The back-off value is taken into
account in link budget separately
for UL / DL and bands: 900/850,
1800/1900)
• Too high MCA (8PSK) can lead to
unsuccessful TBF establishment,
if the MS is on cell border with
low signal level (so the back-off
is taken into account) and / or
low C/I
Pout
Compression point
Back Off= 4 dB
Peak to Average of
Pin
≅ 3,2 dB

14. Burst Structure
• Burst structure is similar with current GMSK burst, but
term 'bit' is replaced by 'symbol'
• Training sequence has lower envelope variations
• Seamless switchover between timeslots
• In case of max output power only, back-off applied to
8-PSK
TSL0
BCCH
GMSK
TSL1
TCH
GMSK
TSL2
TCH
GMSK
TSL3
TCH
GMSK
TSL4
TCH
GMSK
TSL5
PDTCH
8-PSK/
GMSK
TSL6
PDTCH
8-PSK/
GMSK
TSL7
PD CH
T
8-PSK/
GMSK
P(dB)
t(us)

15. EDGE Signal
1
2
3
4
1. Spectrum of Unfiltered 3pi/8 8psk modulation.
2. Filtered to fit GSM bandwidth.
3. Constellation after filtering: error vectors introduced.
4. Constellation after receiver Edge (equalised) filtering

16. GPRS Coding Schemes
• GPRS provides four coding schemes: CS-1, CS-2 and with
PCU2 CS-3, CS-4
• PCU1 and 16 kbit/s Abis links support CS-1 and CS-2, the
Dynamic Abis makes it possible to use CS-3 and CS-4
• Each TBF can use either a fixed coding scheme (CS-1 or
CS-2), or Link Adaptation (LA) based on BLER
• Retransmitted RLC data blocks must be sent with the
same coding as was used initially

17. GPRS Coding Schemes
Nokia GPRS CS3
PCU2
CS4
•
•
181
9.05
268
13.4
312
15.6
428
21.4
CS1 & CS2 – Implemented in all Nokia BTS
without HW change
CS3 & CS4 – S11.5 (with PCU2) and
UltraSite BTS SW CX4.1 CD1 (Talk is
supporting CS1 and CS2)
Error
Correction
Nokia GPRS CS1
PCU1
CS2
Data
Coding Payload (bits) Data Rate
Scheme per RLC block
(kbit/s)
More Data
=
Less Error
Correction

18. GPRS Coding Schemes
CS-1
CS-1
CS-3
RLC/MAC Block Size:
BCS +4
USF
CS-3
181
268
312
Block Check Sequence:
MAC
CS-2
40
16
16
Precoded USF:
3
6
6
~2/3
~3/4
rate a/b convolutional coding
1/2
length:
456
456 bits
57
57
57
57
57
132
57
57
57
Data rate (kbit/s):
9.05
RLC/MAC Block Size:
BCS
BCS Size:
Precoded USF:
Data rate (kbit/s):
20 ms
676
220
interleaving
MAC
USF
588
0
puncturing
CS-4
CS-2
13.4
428
16
12
21.4
15.6

19. EGPR Modulation and Coding Schemes
S
EGPRS modulation and coding schemes:
Scheme Modulation Data rate
kb/s
MCS-9
MCS-8
MCS-7
59.2
8PSK
54.4
44.8
MCS-6
29.6
27.2
MCS-5
22.4
MCS-4
17.6
MCS-3
GMSK
14.8
13.6
MCS-2
MCS-1
Ref: TS 03.64
11.2
8.8

20. EGPR Data Treatment Principle in RF Layer
S
Adding
redundancy
Puncturing of
the coded info
User data
"Additional info" that does not require extra
protection
Header part, robust coding for secure
transmission

21. (E)GPRS Mobile Terminal Classes
•
•
•
Class C
Packet only
(or manually switched between GPRS and speech modes)
Class B
Packet and Speech (not at same time)
(Automatically switches between GPRS and speech modes)
Class A
Packet and Speech at the same time
(DTM is subset of class A)
BTS
BSC

22. (E)GPRS Multislot Classes
Type 1
1 TSL for Measurement
Multislot Classes 1-12
Max 4 DL or 4 UL TSL (not atDL
same time)
UL
- Up to 5 TSL shared between UL and
DL
- Minimum 1 TSL for F Change
- 2-4 TSL F Change used when idle
measurements required
DL
Multislot Classes 19-29
UL
- Max 8 downlink or 8 uplink
(not required at same time)
- 0-3 TSL F Change
Multislot Classes 30-45 ( Rel-5 )
- Max 5 downlink or 5 uplink (6
shared)
Type 2
- Max 6 downlink or 6 uplink (7
shared)
Multislot Classes 13-18
- simultaneous receive & transmit
- max 8 downlink and 8 uplink
(Not available yet, difficult RF
design)
DL
UL
1 TSL for F Change

23. GPRS implementation
• GPRS/EGPRS capable terminals are required
• GPRS territory is required in BTS
• Packet Control Units (PCUs) need to be implemented in
BSCs
• Gb interface dimensioning
• GPRS packet core network dimensioning
• If CS3&CS4 will be implemented following units/items are
required
• PCU2 with S11.5 BSC SW
• Dynamic Abis Pool (DAP)
• EDGE capable TRXs
• UltraSite and MetroSite BTS SW support

24. EGPR Implementation
S
• Can be introduced incrementally to the network where
the demand is
• EGPRS capable MS
• Network HW readiness/upgrade (BTS and TRX)
• TRS capacity upgrade ( Abis and Gb! )
• Dynamic Abis
EDGE capable
TRX,
GSM compatible
EDGE functionality
in the network
elements
GGSN
SGSN
BTS
Gn
BSC
A-bis
Gb
A
BTS
EDGE capable
terminal,
GSM compatible
8-PSK coverage
GMSK coverage
More capacity in interfaces
to support higher data
usage
MSC

25. Enabling (E)GPRS
The steps to create radio network objects
Create a BCF
Create a BTS
Create handover and power control
parameters
Attach BTS to RAC
Enable EGPRS (EGENA/Y)
Define GPRS and EGPRS parameters
Enable GPRS (GENA/Y)
Create a TRX with DAP connection
RAC= Routing Area code

26. Enabling (E)GPRS
The steps to enable the (E)GPRS in BSC
Create the dynamic Abis pool
Disable the GPRS in the cell
Lock the BTS
Lock the TRX
Delete the TRX to be connected to
Dynamic Abis pool
Create a TRX which uses the dynamic Abis
pool
All the TRXs that will be using EGPRS in the BTS must be attached
to a dynamic Abis pool
Unlock the TRX
Enable EGPRS in the BTS (EGENA/Y)
Enable GPRS in the cell (GENA/Y)
Unlock the BTS

27. Enabling (E)GPRS
To be considered:
• When the TRX has been created with EDAP defined at BSC and EGPRS
feature is enabled, the TRX must be attached to EDAP on the BTS
side also not to fail the configuration of BCF
• EDAP in BSC must be inside the TSL boundaries defined in the BTS side
• When modifying EDAP the size of EDAP in the BTS has to be the same as
the size of EDAP in the BSC
• Creating, modifying or deleting of EDAP in the BSC will cause a
territory downgrade/upgrade procedure to all territories served by
the PCU in question
• The ongoing EGPRS/GPRS connections will pause and resume immediately
• The maximum EDAP size is 12 timeslots
• EDAP must be located on the same ET-PCM line as TRX signaling and
traffic channels
• There are no specific commissioning tests concerning EDAP

28. (E)GPRS Protocol Architecture
Relay
IP
IP
GPRS Bearer
User information transfer
User information transfer
Um
APP
TCP/UDP
IP
SNDCP
LLC
RLC
MAC
GSM RF
MS
GGSN
Gn
Gb
Compression, segmentation
Ciphering and reliable link
RLC
BSSGP
MAC
NW sr
GSM RF
L1bis
BSS
L2
L1
Relay
SNDCP
GTP
LLC
BSSGP
NW sr
L1bis
Gi
USER
PAYLOAD
UDP
IP
L2
L1
SGSN
GPRS IP Backbone
GTP
UDP
IP
L2
L1
GGSN
APP
TCP/UDP
IP
L2
L1
FIXED HOST
Internet

29. (E)GPRS Logical Channels
GPRS Air Interface Logical Channels
CCCH
Common Control Channels
PCH
Paging CH
AGCH
Access Grant CH
RACH
Random Access CH
Existing GSM Channels
(Shared with GPRS Signaling in GPRS Release 1)
DCH
Dedicated Channels
PACCH
Packet Associated
Control CH
PDTCH
Packet Data TCH
NEW GPRS Channels

30. Functionality - Content
Introduction
• Network architecture and Interfaces
• Mobile classes
• Network Protocols
• Multiframe and header structure
• Air interface mapping – physical and logical channel
Procedures
• State and Mobility Management
• GPRS Attach/Detach
• Routing Area
• Session Management (PDP context)
• Temporary Block Flow
•RLC/MAC Header
•TBF Establishment

31. (E)GPRS Procedures - Content
• Mobility Management and State Management
• Mobile States
• GPRS attach
• GPRS detach
• Routing Area
• Session Management
• PDP context activation
• Temporary Block Flow
• RLC/MAC Header
• TBF establishment

32. GPRS Mobility Management - Mobile States
GPRS
Attach/De
tach
READY
Timer
expiry
IDL
E
MOBILE
REACHABLE
Timer expiry
MS location not
known, subscriber
is not reachable
by the GPRS nw.
STANDB
Y
MS location
known to
Routing Area
level. MS is
capable to being
paged for pointto-point data.
READ
Y
Packet
TX/RX
MS location known
to cell level. MS is
transmitting or
has just been
transmitting. MS is
capable of
receiving point-topoint data.

33. Attach Procedure
• The GPRS Attach procedure establishes a GMM context.
This procedure is used for the following two purposes:
• a normal GPRS Attach, performed by the MS to attach the
IMSI for GPRS services only
• a combined GPRS Attach, performed by the MS to attach
the IMSI for GPRS and non-GPRS services
• Attach procedure description
• MS initiates by sending Attach Request
• If network accepts Attach Request it sends Attach
Accept
• P-TMSI, RAI
• If network does not accept Attach request it sends
Attach Rejected
• MS responds for Attach Accept message with Attach
Complete (only if P-TMSI changes)

34. Detach Process
• GPRS Detach procedure is used for the following two
purposes:
• a normal GPRS Detach
• a combined GPRS Detach (GPRS/IMSI detach, MS originated)
• MS is detached either explicitly or implicitly:
• Explicit detach: The network or the MS explicitly requests
detach.
• Implicit detach: The network detaches the MS, without
notifying the MS, a configuration-dependent time after
the mobile reachable timer (MSRT) expired, or after an
irrecoverable radio error causes disconnection of the logical
link

35. Routing Area
The Routing Area Update procedure is used for the
followings:
• a normal Routing Area Update
• a combined Routing Area Update
• a periodic Routing Area Update
• an IMSI Attach for non-GPRS services when the MS is
IMSI-attached for GPRS services.
• Routing Area (RA)
• Subset of one, and only one Location Area (LA)
• RA is served by only one SGSN
• For simplicity, the LA and RA can be the same
• Too big LA/RA increases the paging traffic, while too small
LA/RA increases the signaling for LA/RA Update

36. Routing Area
• Bad LA/RA border design can significantly increase the
TRXSIG on LA/RA border cells causing the cell-reselection
outage to be longer
• LA/RA border should be moved from those areas where
the normal CSW and PSW traffic is very high

37. Session Management - Establishing a PDP Context
• PDP Context (Packet Data Protocol): Network level
information which is used to bind a mobile station
(MS) to various PDP addresses and to unbind the
mobile station from these addresses after use
• PDP Context Activation
•
•
•
•
Gets an IP address from the network
Initiated by the MS
Contains QoS and routing information enabling data transfer
between MS and GGSN
PDP Context Activation and Deactivation should occur within
2 seconds
xt
Conte
PDP
st
Reque
.55
5.131.33
15

38. PDP Context Activation - 1
Um
BTS
1. MS sends "Activate PDP Context Request" to
SGSN
2. SGSN checks against HLR
PSTN
Network
BSC
HLR/AuC
EIR
MSC
APN= "Intranet.Ltd.com"
Domain
Name Server
(DNS)
1
Serving
.
GPRS
Support
Node
(SGSN)
GPRS
backbone
network
(IP based)
2
.
SS7
Network
Access Point
Gateway
GPRS
Support Node
(GGSN)
Data
network
(Internet)
GPRS
INFRASTRUCTU
RE
Data
network
(Internet)
Access Point Name = Reference to an external packet data network the user wants to
connect to

39. PDP Context Activation - 2
Finding the GGSN
Um
BTS
3. SGSN gets the GGSN IP address from DNS
4. SGSN sends "Create PDP Context Request"
PSTN
Network
BSC
HLR/AuC
EIR
MSC
3
.
Domain
Name Server
(DNS)
to GGSN
SS7
Network
Serving
GPRS
Support
Node
(SGSN)
GPRS
backbone
network
(IP based)
Access Point
4
.
Gateway
GPRS
Support Node
(GGSN)
Data
network
(Internet)
Data
network
(Internet)
DNS ( Domain Name System ) = mechanism to map logical names to IP addresses
GPRS
INFRASTRUCTU
RE

40. PDP Context Activation - 3
Access Point Name refers to the
external network the subscriber
wants to use
Access Point Selection
Um
BTS
PSTN
Network
BSC
HLR/AuC
EIR
MSC
Domain
Name Server
(DNS)
Serving
GPRS
Support
Node
(SGSN)
GPRS
backbone
network
(IP based)
SS7
Network
Access Point
Gateway
GPRS
Support Node
(GGSN)
Data
network
(Internet)
APN=
"Intranet.Ltd.com"
Data
network
(Internet)
GPRS
INFRASTRUCTU
RE

41. PDP Context Activation - 4
User ( dynamic ) IP address allocated
5. GGSN sends "Create PDP Context Response" back to
SGSN
Context Activated
6. SGSN sends “Activate PDP Context Accept“ to the MS
Um
BTS
PSTN
Network
BSC
HLR/AuC
EIR
MSC
6
Serving
.
Domain
Name Server
(DNS)
SS7
Network
GPRS
Support
Node
(SGSN)
GPRS
backbone
network
(IP based)
Access Point
5
.
Gateway
GPRS
Support Node
(GGSN)
Data
network
(Internet)
APN=
"Intranet.Ltd.com"
Data
network
(Internet)
GPRS
INFRASTRUCTU
RE

42. Temporary Block Flow
Temporary Block Flow ( TBF ) :
• Physical connection where multiple mobile stations can share one or
more traffic channels – each MS has own TFI
• The traffic channel is dedicated to one mobile station at a time (one
mobile station is transmitting or receiving at a time)
• Is a one-way session for packet data transfer between MS and BSC
(PCU)
• Uses either uplink or downlink but not both (except for associated
signaling)
• Can use one or more TSLs
Comparison with circuit-switched:
• normally one connection uses both the uplink and the downlink
timeslot(s) for traffic
In two-way data transfer:
• uplink and downlink data are sent PACCH for downlink TBF) below
Uplink TBF (+ in separate TBFs - as
Downlink TBF (+ PACCH for uplink TBF)
BS
C
PACCH (Packet Associated Control Channel): Similar to GSM CSW SACCH

43. TLLI /TBF Concept
HLR
IMSI
MS
BSS
TMSI
SGSN
P-TMSI
BTS
VLR
PCU
GGSN
GPRS CORE
TBF (TFI + TSL)
TBF (RLC / MAC Flow)
TBF (LLC Flow)
TLLI (SNDCP Flow)
Internet or
Intranet

44. Multiple Mobiles and Downlink Transmission
The TFI included in the Downlink RLC Block header
indicates which Mobile will open the RLC Block
associated with its TBF
TFI3
RLC Data Block
TFI2
TFI5
TFI2
MSs
BTS

45. Multiple Mobiles and Uplink Transmission
•
Several mobiles can share one timeslot
•
Maximum of 7 Mobiles are queued in the Uplink
•
Mobile transmissions controlled by USF (Uplink State Flag) sent on DL
Uplink State Flag
(dynamic allocation)
TS 1
TS 2
New MS
TS 3
•
Mobile with correct USF will transmit in following Uplink block
•
Timeslot selected to give maximum throughput

46. Multiple Mobiles and Uplink Transmission
The USF included in the Downlink RLC Block header identifies
which Mobile will transmit in the following Uplink RLC Block
USF = 3
RLC Data Block
USF = 3
USF = 2
USF =
1
MSs
BTS

47. (E)GPRS Resource Allocation - Content
Territory method
• Default and dedicated territory
• Free TSLs
TSL Allocation
• Scheduling with priority based QoS

48. Territory Method
TRX 1 BCCH SDCCH TS
TS
TS
TS
TS
TS
TS
TS
TS
Territory border
TRX 2
TS
TS
TS
BCCH = Signaling
TS
TS
TS
= CSW Territory
TS
= Free TSL for CSW
TS
= (E)GPRS Territory/Additional capacit
TS
TS
= (E)GPRS Territory/ Default capacity
= (E)GPRS Territory/Dedicated capacit

49. EDAP, PCU and Gb Functionality - Content
EDAP
• Abis vs. Dynamic Abis
• Channels carried on EDAP
• EDAP limits
• Abis PCM structure
PCU
• PCU procedures
• PCU types and limits
Gb
• Gb protocols
• Gb over FR
• Gb over IP

50. BTS
Abis Basic Concepts – PCM frame (E1)
One 64 kbit/s (8 bits) channel in PCM
frame is called timeslot (TSL)
One 16 kbit/s (2bits) channel timeslot
is Sub-TSL
PCM frame has 32 (E1) or 26 (T1)
TSLs
One Radio timeslot corresponds one 16 kbit/s
Sub-TSL (BCCH, TCH/F etc.) and one TRX
takes two TSLs from Abis
One TRX has dedicated TRXsig of 16, 32 or 64 kbit/s.
48 kbit/s isnot allowed.
One BCF has dedicated BCFsig (16 or
64 kbit/s) for O&M
Q1-management needed if TRS
management under BSC
MCB/LCB required if loop topology is used
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18 TCH 0
19 TCH 4
20
21
22
23
24
25 TRXsig
26
27 BCFsig
28
29
30
31
BSC
Abis
MCB
TCH 1
TCH 5
LCB
TCH 2
TCH 6
TCH 3
TCH 7
Q1-management
TRX1

51. (E)GPRS Dynamic Abis Pool – EDAP Introduction
• Fixed resources for signaling
and voice
• Dynamic Abis pool (DAP) for
data
• Predefined size 1-12 PCM
TSL per DAP
• DAP can be shared by
several TRXs in the same
BCF (and same E1/T1)
• Max 20 TRXs per DAP
• Max 480 DAPs per BSC
• DAP + TRXsig + TCHs have
to be in same PCM
• UL and DL EDAP use is
independent
• DAP schedule rounds for
each active Radio Block
• Different users/RTSLs
can use same EDAP SubTSL
0
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
30
31
MCB
LCB
TCH 0
TCH 4
TCH 0
TCH 4
TCH 0
TCH 4
TCH 1
TCH 5
TCH 1
TCH 5
TCH 1
TCH 5
TCH 2
TCH 6
TCH 2
TCH 6
TCH 2
TCH 6
TCH 3
TCH 7
TCH 3
TCH 7
TCH 3
TCH 7
EDAP
EDAP
EDAP
EDAP
EDAP
EDAP
EDAP
EDAP
EDAP
EDAP
EDAP
EDAP
EDAP
EDAP
EDAP
EDAP
EDAP
EDAP
EDAP
EDAP
EDAP
EDAP
EDAP
EDAP
EDAP
EDAP
EDAP
EDAP
EDAP
EDAP
EDAP
EDAP
TRXsig1
TRXsig3
BCFsig
TRXsig2
Q1-management
TRX1
TRX2
TRX3
EGPRS
pool

52. Nokia Dynamic Abis Dimensioning - with EGPRS Data
Traffic
0
• Fixed master TSL in Abis for all EGPRS air TSL TCH 0
1
• Slave TSL’s (64 k) in EDAP pool for each air 2 TCH 4
3
TCH 0
TSL
4
TCH 4
5
TCH 0
• TRX and for OMU signaling fixed
6
TCH 4
7
TCH 0
• TSL 0 and 31 typically used for signaling
8
TCH 4
• EDAP pool dimensioning considerations
9
TCH 0
10 TCH 4
• Planned throughput in radio interface
11 TCH 0
12 TCH 4
 RTSL territory size
13 TRXsig 1
 MS multiclass
14 TRXsig 3
15
• Number of TRXs/BTSs connected to DAP TRXsig 5
16 BCFsig
17
• Total number of PCU Abis Sub-TSLs
18
19 EDAP1
• Gb link size
20 EDAP1
• GPRS/EDGE traffic ratio
21 EDAP1
22
23
24
25
26
27
28
29
30
31
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
TCH 1
TCH 5
TCH 1
TCH 5
TCH 1
TCH 5
TCH 1
TCH 5
TCH 1
TCH 5
TCH 1
TCH 5
MCB
TCH 2
TCH 6
TCH 2
TCH 6
TCH 2
TCH 6
TCH 2
TCH 6
TCH 2
TCH 6
TCH 2
TCH 6
TRXsig 2
TRXsig 4
TRXsig 6
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
Q1-management
LCB
TCH 3
TCH 7
TCH 3
TCH 7
TCH 3
TCH 7
TCH 3
TCH 7
TCH 3
TCH 7
TCH 3
TCH 7
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
EDAP1
TRX 1
TRX 2
TRX 3
TRX 4
TRX 5
TRX 6
EGPRS DAP

53. Packet Control Unit (PCU) - Introduction
• BSC plug-in unit that controls the (E)GPRS radio
resources, receives and transmits TRAU frames to
the BTSs and Frame Relay packets to the SGSN
• Implements both the Gb interface and RLC/MAC
protocols in the BSS
• Acts as the key unit in the following procedures:
• (E)GPRS radio resource allocation and management
• (E)GPRS radio connection establishment and management
• Data transfer
• Coding scheme selection
• PCU statistics
• The first generation PCUs are optimized to meet
GPRS requirements, i.e. non real time solutions (QoS
classes "Background" and "Interactive“)
• The second generation PCUs (PCU2) supports the
real time traffic requirements and enhanced

54. Gb Interface - Introduction
• The Gb interface is the interface between the BSS and
the Serving GPRS Support Node (SGSN)
• Allows the exchange of signaling information and user
data
• The following units can be found in Gb
• Packet Control Unit (PCU) at the BSS side
• Packet Processing Unit (PAPU) at the GPRS IP backbone
side
Gb
• Each PCU has its own separate Gb interface to the
BSC
SGSN
SGSN
PCU
BSS
PAPU
GPRS

55. Gb Interface
• Allow many users to be multiplexed over the same
physical resource
• Resources are given to a user upon activity
(sending/receiving)
• GPRS signaling and user data are sent in the same
transmission plane and no dedicated physical resources
are required to be allocated for signaling purposes
• Access rates per user may vary without restriction
Gb
from zero data to the maximum possible line rate (e.g., 1
BSC
SGSN
984 kbit/s for the available bit rate of an E1 trunk)
PCU
BSS
PAPU
GPRS

56. RF PLANNING VS DATA PERFOR
MANCE
CONTENTS
• FREQ. PLANNING
•
C/I VS THROUGHPUT GRAPHS

57. Frequency Planning
Combined interference and noise estimations needed for
(E)GPRS link budget
Frequency allocation and C/I level
• The existing frequency allocation has high impact on EGPRS
performance
• Loose re-use patterns will provide better performance for all MCSs
Data rate and network capacity
• EGPRS highest data rates require high C/I, typ > 20dB
& 9
• Possibly no extra spectrum for EDGE so efficient use
existing spectrum is very important
• EGPRS traffic suited to BCCH use - typically the layer
C/I. But limited no. of TSLs available on BCCH; may need
layer too
for MCS-7, 8
of the
with highest
to use TCH
Sensitivity in tighter reuse and higher load
• EDGE can utilize tighter reuse schemes and this is beneficial when
planning for high load with limited frequency resources
• For systems with stringent spectrum constraints, EGPRS can offer
good performance even with tight re-use patterns (1/3 or 3/9).
Load dependent

58. Data rate vs. CIR in Time (Field Measurement)
Good quality environment
140
25
20
100
15
CIR(dB)
Throughput (kbps)
120
80
60
10
40
Data Throughput
Application Throughput
TEMS-C/I-GMSK
Poly. (TEMS-C/I-GMSK)
20
0
5
0
0
10
20
Time (s)
30
40

59. Data rate vs. CIR in Time (Field Measurement)
Average quality environment
120
25
20
80
15
CIR(dB)
Throughput (kbps)
100
60
10
40
Data Throughput
Application Throughput
TEMS-C/I-GMSK
Poly. (TEMS-C/I-GMSK)
20
5
0
0
0
10
20
30
40
Time (s)
50
60
70

60. Data rate vs. CIR in Time (Field Measurement)
Worse quality environment
80
Data Throughput
Application Throughput
TEMS-C/I-GMSK
Poly. (TEMS-C/I-GMSK)
70
60
18
16
14
50
12
40
10
30
8
6
20
4
10
2
0
0
0
50
100
Time (s)
150
CIR(dB)
Throughput (kbps)
20