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1 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
(E)GPRS Network Infrastructure
GPRS IPBackboneNetwork
DNS
CG
GGSN
Internet
Corporate 1Intranet
LIG
Corporate 2Intranet
SS7Network
PSTNMSCBSCBTS
MS
EIR
HLR/AuC
SMS-GMSC
SGSN
SGSN
SGSN
MODEMPOOL FOR DIALUP
Nokia IP650 sec GW
Router
Router
RouterSTM-1
STM-1
SGSN
GGSN
Router
Router
Nokia Security GW
LAN SWITCH
MODEMPOOL FOR DIALUP
Nokia Security GW
Nokia Security GW
Nokia IP650 sec GW
Nokia IP650 sec GW
Nokia Security GW
2 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
BSC
Metro
Hub
SGSN
GGSN
ELECTRICAL ET
GB LINKGB LINK
3 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
NSEI 1 NSEI 2
NSEI 3
NSEI 4
NSEI PLANNING
4 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
Network Element and Configuration Audit - Summary
BSC GGSN
IP/MPLS/IPoATM-
Application Servers
(co-located
2GSGSN
BTS
HLR/AC/EIR
TCSM
TC
MSC/VLR
Abis GbBSC BSC
GGSNGGSN-backbone
Application Servers
2GSGSN
2GSGSN
BTS
HLR/AC/EIR
HLR/AC/EIR
TCSM
TC
MSC/VLR
GnGi
Gs
RF interface
• Coverage
•C/I
• Capacity
• Traffic volume
• Mobility
MS/Client parameters
• GPRS/EDGE capability and release
•Multislot support
Abis interface
• EDAP size / dimensioning
• # of E1/T1s
• GPRS/EDGE traffic
Gb interface
• Bearer size
• IP v.s. FR
• Dimensioning
BTS
• GPRS territory
• BTS HW considerations (TRX & BB-card)
• BTS SW (EPCR)
BSS
• PCU variant & dimensioning
• PCU strategy in mixed configuration
• BSS SW and features
SGSN
• Unit capacity (PAPU etc.)
• BSS Gb Flow control
RF
Server
• load
• settings (Linux/Win)
HLR
• QoS profile
• GPRS settings
5 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
INPUT GIVEN FOR THE GPRS PLANNING
• No. of time slot required for the GPRS territory : CDED=1 and CDEF=1
• No. of BTS per EDAP i.e the No. of sectors prevalent : 3
• No. of time slot used for EDAP on Abis (64 Kbps) : 3 Time slot
• % of upgrade is the Teritory upgrade for the future perspective : 10 %
• No. Of sites planned per BSC : 100
• Access rate (CIR) is the speed required at the GB interface : 256 Kbps
6 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
OUTPUT REQUIRED
• No. of sites per NSEI required
• No. of NSEI required in BSC
• No. of PCU or No. Of BCSU required
• No. Of Gb Link required
• No. of E1 required from the BSC to Metro Hub
7 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
How to calculate what
• No. of EGPRS resources used in 1 sector * No. of sectors : 2 x 3
• No. of time slot/sector * no of time slot used for EDAP :- 2 * 3 = 6
• So total time slots per site 6 + 6 = 12
• 1 NSEI support 256 time slot with upgrade % as 10 so total no of time slots which can be equipped is 256 - 10% of 256 = 230.4 ~ 230
• So no. of sites per NSEI is 230/12 = 19.16 ~ 19
• So no NSEI required / BSC : 100 / 19 = 5.2 +1 (for future use) ~ 6
• 2 NSEI supports 1 BCSU so no. of PCU required : 6/2 = 3
• No. of NSEI required is equivalent to the no. of Gb link = 3
• On 1 E1 we can get 31x64 = 1984 , so access rate can be given by 1 E1 = 1984/ access rate (256) = 1984 / 256 ~ 7
8 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
Coding scheme Data rate
MCS-1 8.8 kbit/s
MCS-2 11.2 kbit/s
MCS-3 14.8 kbit/s
MCS-4 17.6 kbit/s
MCS-5 22.4 kbit/s
MCS-6 29.6 kbit/s
MCS-7 44.8 kbit/s
MCS-8 54.4 kbit/s
MCS-9 59.2 kbit/s
Abis PCM allocation (fixed + pool)
Transmission requirement for EGPRS coding schemes in Abis interface
9 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
EDGE modulations
10 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
GPRS & EGPRS coding schemes
• GPRS has four coding schemes,CS-1...4. All use GMSK.
• EDGE has nine modulation and coding schemes, MCS-1...9.
• MCS-1...4 use GMSK,MCS-5...9 use 8-PSK modulation
• Operator can set the MCS to start with
• E.g. always start with MCS-9
MCS-7
MCS-1
22
MCS-2
28
MCS-3
37
MCS-4
44
MCS-5
56
MCS-6
74
5656
MCS-8
6868
MCS-9
74 74
redundancy fromchannel coding
RLC data block,number of octets
RLC/MAC block(radio block)
CS-1
20
CS-2
30
CS-3
36
CS-4
50
11 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
EDGE link performance
• GPRS with re-transmission with same coding scheme
• Retransmissions with EDGE can be sent with the new scheme
•Bit Error Probability (BEP) is a new MS quality measurement introduced
• In general, a higher coding scheme has higher coding rate, and consequently higher peak throughput, but it also tolerates less noise or interference.
• New parameters
• Max BLER for Ack and Non-Ack modes
• Can be used to tune to use more higher MCS’s
• Mean BEP offset for GMSK and 8-PSK
• Set threshold for MCS change
• The figure shows throughput vs. C/I of EGPRS coding schemes in TU50iFH, without incremental redundancy.
0
10
20
30
40
50
60
0 5 10 15 20 25 30
MCS-1MCS-2MCS-3MCS-4MCS-5MCS-6MCS-7MCS-8MCS-9
Ideal Link AdaptationIn RLC layer (kbit/TSL)
C/I
12 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
GPRS: territory (S9-10)
AVG. AVAILABLE TCH in CS territoryava_15 (S9)ave_avail_TCH_sum/ ave_avail_TCH_den
AVG. AVAILABLE GPRS CHANNELS in PS territoryava_16 (S9)ave_GPRS_channels_sum/ave_GPRS_channels_den
AVG. AVAILABLE DEDICATED GPRS CHANNELSava_17 (S9) ave_GPRS_channels_sum/ave_GPRS_channels_den
PEAK DEDICATED GPRS CHANNELS/c2066(S9)peak_permanent_gprs_ch
PEAK GPRS CHANNELS/c2063(S9) peak_gprs_channels
Used capacity for GPRS
The following are the operator configurable parameters for territorymanagement:
GPRSenabled (BTS-level)
GPRSenabledTRX (TRX-level)
DedicatedGPRScapacity (BTS-level)
DefaultGPRScapacity (BTS-level)
PreferBCCHfreqGPRS (BTS-level)
TerritoryUpdateGuardTimeGPRS (BSC-level)
GENA
GTRXCDED
CDEFBFG
GTUGT
ADDIT.GPRS CH USEDach_1
UNAVAILABLE TCHc2040
AVG. BUSY TCH = CS traffictrf_12bave_busy_tch/ res_av_denom14
AVG. TSL used for UL GPRS trf_78b
AVG. TSL used for DL GPRS trf_79b
Free capacity
Allocated resources
Usedresources
CDEDCDEF
Used capacity for speech
Availability ava_1d
The main principle is that GPRS (PS) uses the capacity that remains from the CS traffic.
Given as % over dual TCH tsls ofGPRS enabled TRXs. Includes dedicated time slots. Rounded downwards.
• Circuit Switched traffic has priority
• In each cell Circuit Switched & Packet Switched territories are defined
• Territories consist of consecutive timeslots
TRX 1
TRX 2
CCCH TS TS TS TS TS TS TS
TS TS TS TS TS TS TSTS
DedicatedGPRS
Capacity
CircuitSwitchedTerritory
PacketSwitchedTerritory
Territory border movesDy n a m ic a l ly based onCircuit Switched traffic load
Circuit Switched capacity not affected
by introducing GPRS
DefaultGPRS
Capacity
AdditionalGPRS
Capacity
13 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
RTSL
RequestsTRX 1
0 1 2 3 4 5 6 7
- - CS-2 MCS-1 MCS-9 MCS-7 MCS-1 MCS-7
Grants- - CS-2 MCS-1 MCS-9 MCS-7 MCS-1 MCS-7
PC
M T
SL
PCM subTSL
1 2 3 4
8
11109
5
2
5
-
5
-
-
-7 7 7 -4 4 4 4
• There are enough EDAP resources to handle adequately all the TBFs and MCS requests. (e.g PS Active EGPRS ch < EDAP resources)
DL Data Scheduling Example – “No need to share case”
14 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
DL Data Scheduling Example (sharing case)
Grants
RTSLRequestsTRX 1
0 1 2 3 4 5 6 7
- - CS-2 MCS-5 MCS-9 MCS-8 MCS-1 MCS-7
- - CS-2 MCS-5 MCS-7 MCS-7 MCS-1 MCS-6PCU-TRX 0
5
2
35
7
5
744 4 -P
CM
TS
L
PCM subTSL
1 2 3 4
1112
10
-
• Because EDAP is a shared resource between a higher number of EGPRS TSL it is possible to encounter the situation where there are not enough EDAP resources to handle “adequately” all the TBFs (e.g PS Active EGPRS ch > EDAP resources)
15 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
EDAP utilization
TRX 2
TRX 1
TS TS TS TS TS TS
TS TS T TS TSTS TS TSSPBCCHBCCH
TSTS
TS
TS
Dedicated EGPRS TSL
Default territory EGPRS TSL
•6 EGPRS RTSLs (Dedicated + Default territory)• 50 % utilization assumed (3 Data Erlangs traffic)• On average 3 RTSLs used
• RTSLs use MCS7 (44.8 kbit/s) with average C/I=13dB and throughput 30kbit/s• Effective data rate factor excluding retransmissions over the air-interface is 30/44.8 ~ 0.7
• Slave group utilization is 0.7*0.5= 0.35
16 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
PLAN A PLAN B
17 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
SNO PLAN A PLAN B
1Both Non BCCH and
BCCH Trx can access the EDGE Facility
Only BCCH TRX can access the EDGE facility
2
If the BCCH TRX goes faulty then also the EDGE users can access the N/W
since the 2nd TRX has been defined on the
EDAP Pool
If BCCH TRX goes faulty then The EDGE Service can not be accessed
since the 2nd TRX has not been defined on the EDAP POOL
3
Using this plan we can change the BFG priority
depending on the Interference in the N/W
We can not change the BFG unstill and unless the EDAP pool need to be
redesigned
4
In case of extending the time slot of EDGE in Non BCCH TRX also can be done if congestions is observed in the Site
We can not extend the Non BCCH TRX time slot during the congestion since that TRX is not mapped on the
EDAP Pool
5
While expanding the N/W from the 222 to 332
configuration we need to Modify the EDAP pool
Need not to modify the EDAP pool since only BCCH TRX is being
mapped
18 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
Company Confidential
Conclusion
• The No. of sites per NSEI depend on the EDAP pool size and no. of time slot used for the GPRS territory
• Beside if we need to extend the resourced at ABIS end we need to defince the EDAP pool
• If we require the Speed at GB we need to go to higher CIR