DAP Configuration
Transcript of DAP Configuration
For internal use only1 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 4, 2010
24 June 2010
GPRS / EDGE Workshop
For internal use only2 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Course Agenda
• EDGE – GPRS Theory (Overview)
• PCU – Gb - Bearer Theory (Overview)
• Non Voice KPI (Meaning, Standard Value, Counter, How to Define, Improvement & Measure, Tool)
–
DL – UL Retransmission
–
DL – UL Package Success
–
DL – UL Throughput per TBF
–
% TBF Reject
–
% Gb Utilization
For internal use only3 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 4, 2010
GPRS – EDGE Theory Overview
For internal use only4 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
MSC HLR/Au CEIR
BS C
BT S
U m
PSTNNetwork
GSM & (E)GPRS Network Architecture
PC U
EDAPGb
Gateway GPRSSupport Node(GGSN)
Charging Gateway (CG) Local
AreaNetwor k
Serve r
Route r
Corporate 1
Serve r
Route r
Corporate 2
Datanetwork(Internet)
Datanetwork(Internet )
Billing System
Inter- PLMNnetwork
GPRSINFRASTRUCT URE
BorderGateway (BG)
Lawful InterceptionGateway (LIG)
GPRSbackbon
enetwork
(IP based)
Serving GPRSSupport Node(SGSN)
SS7Network
PA PU
For internal use only5 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
(E)GPRS Network Elements and Primary Functions
SGSN•
Mobility Management•
Session Management•
MS Authentication•
Ciphering•
Interaction with VLR/HLR
•
Charging and statistics•
GTP tunnelling to other GSNs
GGSNGTP tunnelling to other GSNsSecure interfaces to external networksCharging & statisticsIP address management
Charging GatewayCDR consolidationForwarding CDR information to billing center
Border Gateway•
Interconnects different GPRS operators' backbones
•
Enables GPRS roaming•
Standard Nokia IP router family
Domain Name Server•
Translates IP host names to IP addresses
•
Makes IP network configuration easier
•
In GPRS backbone SGSN uses DNS to get GGSN and SGSN IP addresses
•
Two DNS servers in the backbone to provide redundancy
Legal Interception Gateway•
Enables authorities to intercept subscriber data and signaling
•
Chasing criminal activity•
Operator personnel has very limited access to LI functionality
•
LI is required when launching the GPRS service
For internal use only6 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
GSM and (E)GPRS Interfaces
Gf
D
Gi
Gn
GbGc
CE
Gp
Gs
Signaling and Data Transfer InterfaceSignaling Interface
MSC/VLR
TE MT BSS TEPDNR Um
GrA
HLR
Other PLMN
SGSN
GGSN
Gd
SM-SCSMS-GMSCSMS-IWMSC
GGSN
EIR
SGSN
Gn
For internal use only7 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
BSC
BTS
• 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)
(E)GPRS Mobile Terminal Classes
For internal use only8 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
(E)GPRS Multislot Classes
Type 1
Multislot
Classes 1-12-
Max 4 DL or 4 UL TSL (not at same time)-
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
Multislot
Classes 19-29-
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)-
Max 6 downlink or 6 uplink (7 shared)
Type 2
Multislot
Classes 13-18-
simultaneous receive & transmit-
max 8 downlink and 8 uplink(Not available yet, difficult RF design)
DLUL
DLUL
1 TSL for F Change
1 TSL for Measurement
DLUL
For internal use only9 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
GPRS implementation
GPRS/EGPRS capable terminals are requiredGPRS territory is required in BTSPacket Control Units (PCUs) need to be implemented in BSCsGb
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
For internal use only10 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
EGPRS ImplementationCan 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
GMSK coverage
8-PSK coverage
AA-bis
Gb
Gn
BTS
BTS
BSC
SGSNGGSN
MSC
More capacity in interfaces to support higher data usage
EDGE capable TRX, GSM compatible
EDGE capable terminal, GSM compatible
EDGE functionality in the network elements
For internal use only11 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
(E)GPRS Protocol Architecture
L1L2IP
UDPGTP
USERPAYLOAD
GGSN
L1L2
IP
GPRS Bearer
GGSN
Relay
IP
GPRS IP Backbone
L1L2IP
GTP
L1bisNW sr
BSSGP
SNDCPLLC UDP
SGSN
Relay
Gn
Internet
L1L2IP
TCP/UDPAPP
Gi
User information transferUser information transfer
LLCSNDCP
IPTCP/UDP
APP
RLCMAC
GSM RF
MS
RLCMAC
GSM RF
BSSGPNW srL1bis
BSS
Ciphering and reliable link
Um Gb
Compression, segmentation
FIXED HOST
For internal use only12 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
SNDCP (Subnetwork Dependent Convergence Protocol) Layer
Multiplexer/demultiplexer
for different network layer entities onto LLC layerCompression of protocol control information (e.g. TCP/IP header)Compression of data content (if used)Segmentation/de-segmentation of data to/from LLC layer LLC
SNDCP
IP
TCP/UDP
APP
RLC
MAC
GSM RF
For internal use only13 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Logical Link Control (LLC) Layer
LLC
SNDCP
IP
TCP/UDP
APP
RLC
MAC
GSM RF
•Reliable logical connection between SGSN and M•Independent of underlying radio interface protoco
ControlAddre
ss
FCSInformation
LLC Frame
1 1-3 1-1520 3 Octets
For internal use only14 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Radio Link Control (RLC)/ Medium Access Control (MAC) Layers
RLCAchieves reliable transmission of data across air interfaceSegmentation/de-segmentation of data from/to LLC layer
MACControl of MS access to common air-interface mediumFlagging of PDTCH/PACCH occupancy LLC
SNDCP
IP
TCP/UDP
APP
RLC
MAC
GSM RF
For internal use only15 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
GSM RF Layer
Modulation/demodulation Bit inter-leavingTDMA frame formattingCell selection/re-selection Tx
power controlDiscontinuous reception (DRx)LLC
SNDCP
IP
TCP/UDP
APP
RLC
MAC
GSM RF
For internal use only16 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Bursts on the Air Interface – Mapping RLC blocks
1 TDMA frame = 4.615 ms= BURST PERIOD
RLC/MAC Blocks
TDMA Bursts
RLC Blocks
4 x TDMA Frames = 4 Bursts = 1 Radio block = 18.46 ms = 1-2 RLC block(s)
Note: Amount of RLC blocks per radio block
depends on used (modulation) coding
scheme (M)CS0 70 70 70 7
12 x RLC/MAC Blocks = 1 x 52 PDCH MultiFrame = 240 ms12 RLC/MAC Blocks / 0.240 s = 50 RLC/MAC Blocks / s
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
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
B0(0..3)
B1(4..7)
B2 (8..11)
PTCCH
B3(13..16)
B4(17..20)
B5(21..24) IDLE
B6(26..29)
B7(30..33)
B8(34..37) PTCCH
B9(39..42)
B10(43..46)
B11(47..50) IDLE
52 TDMA Frames (240 ms)
For internal use only17 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
(E)GPRS Logical Channels
GPRS Air Interface Logical Channels
CCCHCommon Control Channels
DCHDedicated Channels
PCHPaging CH
AGCHAccess Grant CH
RACHRandom Access CH
Existing GSM Channels(Shared with GPRS Signaling in GPRS Release 1)
PACCHPacket Associated
Control CHPDTCH
Packet Data TCH
NEW GPRS Channels
For internal use only18 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
GPRS Mobility Management - Mobile States
MS location not known, subscriber is not reachable by the GPRS nw.
IDLE READ
Y
STANDBY
READY Timer expiry
MOBILE REACHABLE
Timer expiry
Packet TX/RX
GPRS Attach/Detach
MS location known to Routing Area level. MS is capable to being paged for point-to-
point data.
MS location known to cell level. MS is transmitting or has just been transmitting. MS is capable of receiving point-to-point data.
For internal use only19 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
GPRS Mobility Management - Mobile States
GPRS MM is based on StatesState Transition occurs when a pre-defined transaction takes placeGPRS Attach (/Detach)•
MS makes itself known to the network
•
The authentication is checked and the mobile location is updated•
Subscriber Information is downloaded from the HLR to the SGSN
•
State transition Idle to Ready•
Normal procedure should occur within 5 seconds each
Mobility Management before Session Management:•
GPRS attach needs to happen before PDP context activation
States controlled by timers•
READY Timer
•
MOBILE REACHABLE Timer•
Timer values are configurable with SGSN Parameter Handling
For internal use only20 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Territory Method
Territory method is used to divide the CS and PS resources•
Timeslots within a cell are dynamically divided into the CS and (E)GPRS territories
•
Number of consecutive traffic timeslots in (E)GPRS territory are
reserved (or initially available) for (E)GPRS traffic, the remaining timeslots are available for GSM voice
•
The dynamic variation of the territory boundary are controlled by territory parameters
•
The system is able to adapt to different load levels and traffic
proportions, offering an optimized performance under a variety of load conditions
•
The PS territory can contain dedicated, default and additional capacity–
Dedicated capacity: number of timeslots are allocated to (E)GPRS on a permanent basis i.e. are always configured for (E)GPRS and cannot be used by the circuit switched traffic. This ensures that the (E)GPRS capacity is always available in a cell
–
Default capacity: the (E)GPRS territory is an area that always is included in the instantaneous (E)GPRS territory, provided that the current CS traffic levels permit this
–
Additional capacity= Additional (E)GPRS capacity means the extra
time slots beyond the default capacity which are assigned due to a load demand.
For internal use only21 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Territory Method
TRX 1
TRX 2
BCCH TS TS TS TS TS TSSDCCHBCCH TS TS TS TS TS TSSDCCHBCCH TS TS TS TS TS TSSDCCH
TS TS TSTS TSTS TS TSTS TSTS TS TS TSTS TS TSTS
TS
TS
= (E)GPRS Territory/Dedicated capa
= CSW Territory
TS = (E)GPRS Territory/Additional capa
BCCH= Signaling
TS = Free TSL for CSW
TS = (E)GPRS Territory/ Default capacity
Territory border
For internal use only22 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 4, 2010
PCU – Gb – Bearer Theory Overview
For internal use only23 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
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
For internal use only24 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
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 (E1) TSLs
One Radio timeslot corresponds one 16 kbit/s
Sub-TSL (BCCH, TCH/F etc.) and one TRX takes two TSLs
from Abis
0 MCB LCB123456789101112131415161718 TCH 0 TCH 1 TCH 2 TCH 319 TCH 4 TCH 5 TCH 6 TCH 7202122232425 TRXsig2627 BCFsig28293031 Q1-management
One TRX has dedicated TRXsig
of 16, 32 or 64 kbit/s
One BCF has dedicated BCFsig
(16 or 64 kbit/s) for O&M
TRX1
Q1-management needed if TRS management under BSC
MCB/LCB required if loop topology is used
AbisBTS BSC
For internal use only25 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
(E)GPRS Dynamic Abis Pool – EDAP Introduction
Fixed resources for signaling and voiceDynamic 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 Sub-TSL
0 MCB LCB1234 TCH 0 TCH 1 TCH 2 TCH 35 TCH 4 TCH 5 TCH 6 TCH 76 TCH 0 TCH 1 TCH 2 TCH 37 TCH 4 TCH 5 TCH 6 TCH 78 TCH 0 TCH 1 TCH 2 TCH 39 TCH 4 TCH 5 TCH 6 TCH 7
101112131415 EDAP EDAP EDAP EDAP16 EDAP EDAP EDAP EDAP17 EDAP EDAP EDAP EDAP18 EDAP EDAP EDAP EDAP19 EDAP EDAP EDAP EDAP20 EDAP EDAP EDAP EDAP21 EDAP EDAP EDAP EDAP22 EDAP EDAP EDAP EDAP232425 TRXsig1 TRXsig226 TRXsig327 BCFsig28293031 Q1-management
TRX1TRX2TRX3
EGPRSpool
For internal use only26 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Dynamic Abis - Master and Slave Channels
Master channelFixed TCH Sub-TSL is called master
channelMaster cannel contains user data and
inband
signalling
for TRXSlave channelLocated in EDAPContains user data that does not fit in the
master data frameDynamic Abis Pointer
Each DL PCU master channel includes a pointer to
•DL slave frames on the same block period •UL slave frames on the next block period
M M
S S S
S S S S
downlink PCMframes during
one block period
uplink PCMframes during
next block period
EDAP
For internal use only27 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
EDGE and GPRS –
Master / Slave Channel Usage
Coding scheme
CS-1CS-2CS-3CS-4
MCS-1MCS-2MCS-3MCS-4MCS-5MCS-6MCS-7MCS-8MCS-9
Bit rate (bps)
8,012,014,420,0
8,811,214,817,622,429,644,854,459,2
Abis PCM allocation (fixed + pool/slave)
GPRSand
EDGE
EDGE
•
Higher data rates don’t fit in 16 kbit/s
channels
•
GPRS CS-2 requires 1 slave when EDGE activated (TRX/BTS)
•
32, 48, 64 or 80 kbit/s
Abis
links per RTSL needed
Retrans.
For internal use only28 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Nokia Dynamic Abis Dimensioning - with EGPRS Data Traffic•
Fixed master TSL in Abis
for all EGPRS air TSL •
Slave TSL’s
(64 k) in EDAP pool for each air TSL• TRX and for OMU signaling fixed• TSL 0 and 31 typically used for signaling• EDAP pool dimensioning considerations
• Planned throughput in radio interface RTSL territory size MS multiclass
•
Number of TRXs/BTSs
connected to DAP• Total number of PCU Abis
Sub-TSLs• Gb
link size• GPRS/EDGE traffic ratio
0 MCB LCB1 TCH 0 TCH 1 TCH 2 TCH 32 TCH 4 TCH 5 TCH 6 TCH 73 TCH 0 TCH 1 TCH 2 TCH 34 TCH 4 TCH 5 TCH 6 TCH 75 TCH 0 TCH 1 TCH 2 TCH 36 TCH 4 TCH 5 TCH 6 TCH 77 TCH 0 TCH 1 TCH 2 TCH 38 TCH 4 TCH 5 TCH 6 TCH 79 TCH 0 TCH 1 TCH 2 TCH 3
10 TCH 4 TCH 5 TCH 6 TCH 711 TCH 0 TCH 1 TCH 2 TCH 312 TCH 4 TCH 5 TCH 6 TCH 713 TRXsig 1 TRXsig 214 TRXsig 3 TRXsig 415 TRXsig 5 TRXsig 616 BCFsig171819 EDAP1 EDAP1 EDAP1 EDAP120 EDAP1 EDAP1 EDAP1 EDAP121 EDAP1 EDAP1 EDAP1 EDAP122 EDAP1 EDAP1 EDAP1 EDAP123 EDAP1 EDAP1 EDAP1 EDAP124 EDAP1 EDAP1 EDAP1 EDAP125 EDAP1 EDAP1 EDAP1 EDAP126 EDAP1 EDAP1 EDAP1 EDAP127 EDAP1 EDAP1 EDAP1 EDAP128 EDAP1 EDAP1 EDAP1 EDAP129 EDAP1 EDAP1 EDAP1 EDAP130 EDAP1 EDAP1 EDAP1 EDAP131 Q1-management
TRX 1
TRX 2
TRX 3
TRX 4
TRX 5
TRX 6
EGPRS DAP
For internal use only29 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
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 SGSNImplements both the Gb
interface and RLC/MAC protocols in the BSSActs 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 functionality (GERAN) beyond (E)GPRS
For internal use only30 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Packet Control Unit (PCU) - Variants and Connectivity LimitsPCU types and capacity limitsThe relations between PCU and BSC types as well as the connectivity limits of BTSs, TRXs, TSLs, Abis and Gb TSLs
are shown belowPCU Type BSC Types Network elements BSS10.5 BSS10.5 ED BSS11 BSS11.5PCU BSCE, BSC2, BSCi, BSC2i BTS 64 64 64 64
TRX 128 128 128 128Radio TSLs 256 256 256 128Abis 16 kbps channels 256 256 256 256Gb
64 kbps channels 31 31 31 31PCU-S BSCE, BSC2, BSCi, BSC2i BTS 64 64 64 64
TRX 128 128 128 128Radio TSLs 256 256 256 128Abis 16 kbps channels 256 256 256 256Gb
64 kbps channels 31 31 31 31PCU-T BSCE, BSC2, BSCi, BSC2i BTS 64 64 64 64
TRX 128 128 128 128Radio TSLs 256 256 256 256Abis 16 kbps channels 256 256 256 256Gb
64 kbps channels 31 31 31 31PCU2-U BSCE, BSC2, BSCi, BSC2i BTS N/A N/A N/A 128
TRX N/A N/A N/A 256Radio TSLs N/A N/A N/A 256Abis 16 kbps channels N/A N/A N/A 256Gb
64 kbps channels N/A N/A N/A 31PCU-B BSC3i BTS 2 x 64 2 x 64 2 x 64 2 x 64
TRX 2 x 128 2 x 128 2 x 128 2 x 128Radio TSLs 2 x 256 2 x 256 2 x 256 2 x 256Abis 16 kbps channels 2 x 256 2 x 256 2 x 256 2 x 256Gb
64 kbps channels 2 x 31 2 x 31 2 x 31 2 x 31PCU2-D BSC3i BTS N/A N/A N/A 2 x 128
TRX N/A N/A N/A 2 x 256Radio TSLs N/A N/A N/A 2 x 256Abis 16 kbps channels N/A N/A N/A 2 x 256Gb
64 kbps channels N/A N/A N/A 2 x 31
For internal use only31 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
BSC Types
BSC types and capacity limits
The 75 % utilization of the connectivity is recommended by NokiaThe number of BCSUs
are limiting the max number of PCUs
BSC2i BSC3i BSC3i BSC3i BSC3i BSC3i
Max BCSUs Working 8 2 3 4 5 6
BCSU_Spare 1 1 1 1 1 1
Max PCUs Working (logical) 16 8 12 16 20 24
PCUs_Spare (logical) 2 4 4 4 4 4
Max_RTLs 4096 2048 3072 4096 5120 6144
TRX_MAX 512 110 220 330 440 660
BTS_MAX 512 110 220 330 440 660
BCF_MAX 248 504 504 504 504 504
For internal use only32 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
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 dataThe following units can be found in Gb•
Packet Control Unit (PCU) at the BSS side
•
Packet Processing Unit (PAPU) at the GPRS IP backbone sideEach PCU has its own separate Gb
interface to the SGSN
BSC
PCU
BSS
SGSN
PAPU
GPRS
Gb
For internal use only33 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Gb Interface
Allow many users to be multiplexed over the same physical resourceResources 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 purposesAccess rates per user may vary without restriction from zero data to the maximum possible line rate (e.g., 1 984 kbit/s
for the available bit rate of an E1 trunk)
BSC
PCU
BSS
SGSN
PAPU
GPRS
Gb
For internal use only34 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Gb Interface - Protocols
The Gb
interface can be implemented using the Frame Relay or IP
L1L2IP
UDPGTP
USERPAYLOAD
GGSN
L1L2
IP
GPRS Bearer
GGSN
Relay
IP
GPRS IP Backbone
L1L2IP
GTP
L1bisNS
BSSGP
SNDCPLLC UDP
SGSN
Relay
Gn
Internet
L1L2IP
TCP/UDPAPP
Gi
User information transferUser information transfer
LLCSNDCP
IPTCP/UDP
APP
RLCMAC
GSM RF
MS
RLCMAC
GSM RF
BSSGPNSL1bis
BSS
Ciphering and reliable link
Um Gb
Compression, segmentation
FIXED HOST
For internal use only35 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Gb Interface - FR
The Gb
interface can be implemented using the Frame Relay or IPThe Frame Relay can be :•
Point-to-point (PCU–SGSN)–
spare capacity of Ater
and A interfaces–
any transmission network •
Frame relay network between the BSC and SGSN
In Frame Relay there are different options available:•
Voice and data multiplexed
•
Voice and data separated in the transcoder•
Channels going through the transcoders
and MSC•
Traffic streams concentrated in the FR switch
•
Dedicated 2 Mbit/s
E1 PCM links
BSC MSCTC
SGSN
MU
X
Gb
GbGb
For internal use only36 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Gb Interface - IP
The increased demand for packet switched traffic transmission cost efficiency can be met by deploying IP in the transmission networkIP offers an alternative way to configure the subnetwork
of the Gb
interface:•
the subnetwork
is IP-based and the physical layer is EthernetThe introduction of IP makes it possible to build an efficient transport network for the IP based multimedia services of the futureBoth the IPv6 and IPv4 protocol versions are supportedIP transport can be used in parallel with FR under the same BSC and BCSU
•
Within one BCSU, separate PCUs can use different transmission media
For internal use only37 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Gb Interface - IP
Gb
over IP is an application software product and requires a valid
license in the BSCThe licensing is based on the number of PCUs to which IP Network
Service Entities can be configuredRequires support from both BSC and SGSNIn the BSC, the capacity of the Gb
interface remains the same, regardless of whether IP or FR is used as the transport technology
SGS
N
Gb
IPBT
S
BT
S
BS
C
FR
For internal use only38 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 4, 2010
Parameter Setting & Definition
For internal use only39 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Contents
Territory Parameter•
cdef, cded, cmax, gtrx, gena, egena,
Link Adaptation•
Crosspoint
GPRS, cod, codh
•
BLA, BLU, BEP, etcUL Power Control•
Alpha, gamma, TFP, IFP
BSC Parameter•
MNDL, MNUL, BS_CV_MAX, GTUGT, CSD, CSU
For internal use only40 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Territory Parameter Group
For internal use only41 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Packet Data Channel Parameters Setting
defaultGPRScapacity (CDEF)(BTS)(0..100%) parameter defines the default packet-switched channels in a cell. It is used to set the percentage of available RTSL for GPRS capacity. The capacity is given as a percentage of the total capacity of the cell. Any percentage is rounded up to the closest integer RTSL. A setting of 0.01% means 1 RTSL, and 20% for a 1 TRX cell also means 1 RTSL. The MML default is 1%.dedicatedGPRScapacity (CDED)(BTS)(0..100%) is used to set the dedicated percentage of packet-switched RTSL for GPRS capacity. The capacity is given as a percentage of the total capacity of the cell. The default is 0%. In general, DedicateGPRScapacity
< DefaultGPRScapacity
maxGPRScapacity(CMAX)(BTS)(1..100%)(100%): with this parameter, you define the maximum number of packet switched channels in a BTS.
For internal use only42 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Example of PDCH Setting
Two TRXs
with 15 TCH TimeslotsCDEF = 27% => 4 TimeslotsCDED = 14% => 2 TimeslotsCMAX = 100% => 15 Timeslots
For example with Excel you can calculate the required percentage:=roundup(4/15*100,0) = 27%=roundup(2/15*100,0) = 14%
For internal use only43 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Related Territory Parameters
terrUpdateGuardTimeGPRS (GTUGT)(BSC)(1..255) is used to set the timer which elapses between two adjacent territory updates. The MML default is 5. GPRSenabledTRX (GTRX)(TRX)(Y/N) With this parameter you define whether the GPRS capability is enabled or disabled for the current TRX. GprsEnabled(GENA)(BTS)(Y/N). This parameter defines whether the GPRS capability is enabled in the BTS during normal operation of the cell. EGPRSenable (EGENA)(BTS)(Y/N) with this parameter you enable or disable EGPRS capability of the cell.
For internal use only44 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
GPRS and TRX prioritisation in TCH allocation (1)
In CSW call, It is possible to set priority between the TCH TRXs and BCCH TRX with
TrxPriorityInTCHAllocation (TRP) 0 … 2 where 0 = no
preference1 =BCCH preferred2 =Beyond BCCH
preferenceParameter for GPRS "Prefer BCCH frequencyGPRS" depends on TRP values It indicates whether GPRS allocation is using same preference as CSW
Prefer BCCH frequencyGPRS(BFG) Y / N
For internal use only45 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
GPRS and TRX prioritisation in TCH allocation (2)
TRP BFG CSW preferred GPRS preferred0 Y/N no preferred TCH1 Y BCCH BCCH1 N BCCH TCH2 Y TCH TCH2 N TCH BCCH
For internal use only46 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Link Adaptation Parameter Group
For internal use only47 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Link Adaptation
The task of the LA algorithm is to select the optimal MCS for each radio condition to maximize channel throughput and reduce retransmissionTo maintain good throughput the goal for the LA algorithm is to adapt to situations where signal strength compared to interference level is changing within timeLA adapts to path loss and shadowing but not fast fading
This corresponds to the "ideal LA" curves in link level simulations•
Incremental Redundancy (IR) is better suited to compensate for fast fading
EGPRS LA is implemented in the Packet Control Unit (PCU)In GSM Specification, there is full support for Bit Error Probability (BEP) based Link Adaptation (LA) algorithm
For internal use only48 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Parameter Recommended valueBSC_GPRS_PARAM_ENABLED YPCU_CS_HOPPING 0 (ie LA)PCU_UL_BLER_CP_HOPPING 24%PCU_DL_BLER_CP_HOPPING 20%PCU_CS_NON_HOPPING 2 (Coding Scheme 2)PCU_UL_BLER_CP_NON_HOPPING 90%PCU_DL_BLER_CP_NON_HOPPING 90%PCU_UL_LA_RISK_LEVEL 10%PCU_DL_LA_RISK_LEVEL 20%
Link Adaptation GPRS Parameter
For internal use only49 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Link Adaptation Parameters
Initial
MCS for
acknowledged
mode MCA
Parameter
Name Abbreviatio
n
Initial
MCS used
at
the
beginning
of
a TBF for
acknowledged
mode
Description
1 .. 9, step
1
Range
and
Step
Initial
MCS for
unacknowledged
mode MCU Initial
MCS used
at
the
beginning
of
a TBF for
unacknowledged
mode 1 .. 9, step
1
Maximum BLER in acknowledged mode BLA Maximum block error rate of first transmission in acknowledged mode
10 .. 100%, step
1
Maximum BLER in unacknowledged mode BLU
Maximum block error rate of first transmission in unacknowledged
mode10 .. 100%, step
1
mean BEP offset GMSK MBG
Adjust the MCS and modulation preferences. This is the offset added to reported GMSK mean BEP values before BEP table lookups. The value applies to both uplink and downlink
directions
-31 .. 31, step
1
mean BEP offset 8PSK MBP
Adjust the MCS and modulation preferences. This is the offset added to reported 8PSK mean BEP values
before BEP table lookups. The value applies to both uplink and downlink
directions
-31 .. 31, step
1
ELAEGPRS Link Adaptation Enabled Enables
EGPRS Link Adaptation
for
Ack
mode
or
Ack
and
Unack
mode 0,1,2, default
2
For internal use only50 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Link Adaptation - Initial MCS
Initial
MCS for
acknowledged/ Unacknowledged
mode (MCA/MCU)
•
LA uses always the same MCS at the beginning of the TBF using the parameter MCA and MCU depending on the RLC mode, e.g Acknowledge
or Un-acknowledge.
•
The Optimal MCS depends on the radio conditions and the type of traffic
Studies have been done to determine the optimal value for this parameter. Some of the conclusions reached are listed here:•
With FTP traffic model, MCS-9 is the best initial coding scheme to be used with IR
•
With WWW traffic model, MCS-7 is the best initial coding scheme to be used with IR
•
The initial coding scheme cannot be configured based on the service, so the more conservative value for the initial coding scheme is normally chosen as default (i.e. MCS-7)
For internal use only51 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Link Adaptation - Initial MCS
Results for MCA=5, 7 and 9 respectively.Different MCA cause the TBF to be established at the operator defined value, but the optimum MCS is reached rapidly.
Nethawk
data averaged to smooth graphs.
For internal use only52 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Link Adaptation - Initial MCS
LA Performance MCA=1
0
10
20
30
40
50
60
0 5 10 15 20 25 30
C/I (dB)
Thro
ughp
ut (K
bits
/s)
MCA=1 BLA=90MCA=1 BLA=50MCA=1 BLA=30MCA=1 BLA=10
FTP DL 1Mb 2TSL
Very stable behavior in low C/I
but poor performance when
C/I is high
No big differences for different BLA
values.
Changing MCS more or less
frequently does not make a big difference since the starting point
is
MCS1
For internal use only53 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Link Adaptation - Initial MCS
LA Performance MCA=7
0
10
20
30
40
50
60
70
80
90
0 5 10 15 20 25 30
C/I (dB)
Thro
ughp
ut (K
bits
/s)
MCA=7 BLA=90MCA=7 BLA=50MCA=7 BLA=30MCA=7 BLA=10
Much better performance for
high C/I, but lower throughputs for low
C/I
BLA=50 provides a very
good performance for high C/I. BLA=90 is
never optimal
Big differences for different BLA values.
FTP DL 1Mb 2TSL
For internal use only54 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Link Adaptation - Initial MCS
LA Performance MCA=9
0
10
20
30
40
50
60
70
80
90
0 5 10 15 20 25 30
C/I (dB)
Thro
ughp
ut (K
bits
/s)
MCA=9 BLA=90MCA=9 BLA=50MCA=9 BLA=30MCA=9 BLA=10
Better throughputs overall, but very
unstable in low C/I conditions
No big differences between
different values of BLA
FTP DL 1Mb 2TSL
For internal use only55 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Link Adaptation - Maximum BLER
Maximum BLER in acknowledged/ unacknowledged mode (BLA/BLU).Operator definable Maximum BLER for Ack
and Unack
Mode,
BLA and BLU, set the upper limit for the acceptable BLER when Link Adaptation algorithm selects the optimum MCS.
For internal use only56 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Link Adaptation - Maximum BLER
LA performance BLA = 90%
0
20
4060
80
100
0 10 20 30
C/I (dB)
Thro
ughp
ut (k
bit/s
)
MCA1MCA7MCA9
NTN Results
For internal use only57 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Link Adaptation - Maximum BLER
LA performance BLA = 50%
0
20
4060
80
100
0 10 20 30
C/I (dB)
Thro
ughp
ut (k
bit/s
)
MCA1MCA7MCA9
NTN Results
For internal use only58 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Link Adaptation - Mean BEP Offset for GMSK/8PSKMean BEP offset GMSK/8PSK (MBG/MBP):The offset is added to Mean_BEP values reported by the MS before mapping into the LookUp
tables.
Mean_BEP (LookUp) = Mean_BEP ( MS) + Mean BEP offset 8PSK
Negative MBP/MBG will simulate worse BEP than actual radio conditions impose, therefore more robust MCS, lower MCS, will be generated by LA procedure. E.g average used MCS in the network will be lower. And vice versa, by setting MBP/MBG to positive values we simulate better radio conditions that existing, and therefore LA
will produce less robust, or higher, MCS.
For internal use only59 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Mean_BEP_offset_GSMK & Mean_BEP_offset_8PSK
FTP ThroughputMBG = 0, different MBP
020406080
100
MBP = -20MCS4
MBP = -10MCS4
MBP = 0MCS7
MBP = 10MCS9
MBP = 20MCS9
kbit/
s
C/I adjusted so MCS7 is chosen by the LA algorithm (C/I = 15 dB, MCA = 9)
NTN Results
For internal use only60 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Mean_BEP_offset_GSMK & Mean_BEP_offset_8PSK
C/I adjusted so MCS7 is chosen by the LA algorithm (C/I = 15 dB, MCA = 9)Setting MBP to –31 forces the modulation to be GMSK
FTP Throughput(MBP = -31, different MBG)
05
101520253035
MBG = -31 MCS1 MBG = -23 MCS2 MBG = -20 MCS4
kbit/
s
NTN Results
For internal use only61 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
BEP Filtering Period
Another mean of optimizing the performance of EDGE is by the filtering length of the quality control measurements.
Bit error probability filter averaging period (BEP)With this parameter you define the bit error probability
filter averaging period for EGPRS channel quality measurements.
Range:1,2,3,4,5,7,10,12,15,20,25, Default:10
A rather shorter filtering period would suit better fast MS, and
a longer period for slower MS.Although it is a POC parameter it has effect on EDGE LA procedure.
For internal use only62 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Link Algorithm Response Time
Response time of LA algorithm
0
2
46
8
10
9 -> 7 9 -> 5 9 -> 3 9 -> 1 1 -> 7 1 - > 9
MCS transition
Seco
nd
NTN Results
For internal use only63 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
EGPRS Link adaptation enabled (ELA)
Q3 name: —Modification: OnlineRange:•
0... EGPRS link adaptation is disabled
•
1... EGPRS link adaptation is enabled for RLC aknowledged
mode•
2... EGPRS link adaptation is enabled for both RLC aknowledged
and RLC unacknowledged modes
MML default: 2Description: With this parameter you enable or disable EGPRS link adaptation on cell level. If disabled the the
system uses the MCS value defined by initial MCS for acknowledged mode or initial MCS for unacknowledged mode parameters or a lower MCS.Related command(s): EQV, EQORecommended value: default
For internal use only64 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Initial MCS for acknowledged mode (MCA)
Q3 name: initMcsAckModeModification: OnlineRange: 1 to 9MML default: 9Description: With this parameter you indicate the Modulation and
Coding Scheme (MCS) used at the beginning of a TBF for acknowledged mode. The parameter is used in EGPRS link adaptation.Related command(s): EQV, EQORecommended value: defaultPlanning: The initial MCS (MCA) is an important radio parameter for achieving higher throughput on network level. If the network has
high C/I, MCA should be set to 9. If the C/I is low (less than 12-15 dB), the MCA should be set to e.g. 6. The MCA setting is network and area dependent.
For internal use only65 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Initial MCS for Unacknowledged Mode (MCU)
Q3 name: InitMcsUnackModeModification: OnlineRange: 1 to 9MML default: 6Description: With this parameter you indicate the MCS used at the beginning of a TBF for unacknowledged mode. The parameter is used in EGPRS link adaptation.Related command(s): EQV, EQORecommended value: defaultPlanning: MCU is not an important parameter, since the RLC blocks are in acknowledged operation. (MCU and BLU can be important for some applications that may use RLC unack
mode
and especially once different QoS
are implemented, since RLC mode depends on the Reliability Class.)
For internal use only66 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Maximum BLER in Acknowledged Mode (BLA)
Q3 name: MaxBlerAckModeModification: OnlineRange: 10 to 100 %MML default: 90Description: With this parameter you indicate the maximum block error rate of first transmission in acknowledged mode. The parameter is used in EGPRS link adaptation.Related command(s): EQV, EQORecommended value: default
For internal use only67 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Maximum BLER in UnAcknowledged
Mode (BLU)
Q3 name: MaxBlerUnackModeModification: OnlineRange: 1 to 100MML default: 10Description: With this parameter you indicate the maximum block error rate in unacknowledged mode. The unit is parts per thousand. The parameter is used in EGPRS link adaptation.Related command(s): EQV, EQORecommended value: default
For internal use only68 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Bit Error Probability Period (BEP)
Q3 name: bepPeriodModification: OnlineRange: 1,2,3,4,5,7,10,12,15,20,25MML default: 10Description: With this parameter you define the bit error probability filter averaging period for EGPRS channel quality measurements.Related command(s): EUC, EUM, EUORecommended value: default
For internal use only69 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Mean BEP Offset GMSK (MBG)
Q3 name: meanBepOffsetGMSKModification: OnlineRange: –31 to 31MML default: 0Description: With this parameter you can adjust the MCS and modulation preferences. This is the offset added to reported GMSK mean BEP values before BEP table lookups. The value applies to both uplink and downlink directions. The parameter is
used in EGPRS link adaptation.Related command(s): EQV, EQORecommended value: default
For internal use only70 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Mean BEP Offset 8PSK (MBP)
Q3 name: meanBepOffset8PSKModification: OnlineRange: –31 to 31MML default: 0Description: With this parameter you can adjust the MCS and modulation preferences. This is the offset added to reported 8PSK mean BEP values before BEP table lookups. The value applies to both uplink and downlink directions. The parameter is used in EGPRS link adaptation.Related command(s): EQV, EQORecommended value: defaultPlanning: The algorithm that decides the coding scheme based on the measured BEP values are Nokia-specific, and coded in PCU software. The algorithm is based on simulations by Nokia. The MBP and MBG parameters add an offset to the report BEP measurements before those are processed by the Link Adaptation algorithm. Makes it possible for the operator to influence the choice of coding scheme.Default values are zero => no impact on coding scheme selection.
For internal use only71 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
UL Power Control Parameter Group
For internal use only72 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
UL Power Control
Theoretically the optimized Uplink Power Control can achieve higher signal level as well. Practically it is not so easy to measure the impact of PC on signal level and finally on data rate.
0
5
10
15
20
25
30
35
-30 -40 -45 -50 -55 -60 -65 -70 -75 -80 -85 -90 -95 -100 -105 -110
DL Rx Lev (dBm)
MS
outp
ut p
wr
(dBm
)Gamma = 14
Gamma = 36
Gamma = 28Alpha =0.8
0
5
10
15
20
25
30
35
-30 -40 -45 -50 -55 -60 -65 -70 -75 -80 -85 -90 -95 -100 -105 -110
DL Rx Lev (dBm)
MS
outp
ut p
wr
(dBm
)Gamma = 14
Gamma = 36
Gamma = 28Alpha =0.8
With lower values of Gamma the MS output power is increased, when the user is closer to the BTS. This can help to reduce retransmissions in the UL and improve the performance. The drawback would be that with lower values of Gamma interference in the UL is increased too.
For internal use only73 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Power Control Formula
PCH = min (Γ0
− ΓCH - α∗(C + 48), PMAX )
Where •
ΓCH as one of POC parameter set by operator, determines the minimum MS output power
•
Γ0
(gamma) 34 dBm
for GSM900, 36 dBm
for GSM1800. •
C Is the received signal level at the MS.
•
α
(alpha) as another POC parameter setting by operator, determine
the slope by which the downlink RX_LEVEL effects the power.
•
Pmax is the maximum allowed output power in the cell (broadcast parameter) or the MS power class whichever is the smallest.
For internal use only74 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Binary Representation ALPHA (ALPHA)
GSM reference: ETS 300 940 (GSM 04.08)Q3 name: alphaModification: OnlineRange: 0...10 according to the following principle:
0: α=0.01: α=0.12: α=0.2...10: α=1.0
MML default: 7 (GSM 800 and GSM 900)8 (GSM 1800 and GSM 1900)
Description: With this parameter you describe the binary representation of the parameter α.Related command(s): EUC, EUM, EUONote: OPTIONAL (Gb
Interface functionality)Recommended value: default.
For internal use only75 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Binary Representation TAU (GAMMA)
GSM reference: ETS 300 940 (GSM 04.08)Q3 name: gammaModification: OnlineRange: 0...62 (dB) with a step size of 2MML default: 34 (GSM 800 and GSM 900)
36 (GSM 1800 and GSM 1900)Description: With this parameter you describe the binary representation of the parameter τ
ch
for MS output power
control.Related command(s): EUC, EUM, EUONote: OPTIONAL (Gb
Interface functionality)
Recommended value: default.
For internal use only76 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
BSC Parameter Group
For internal use only77 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Maximum Number of DL TBF (MNDL)
Q3 name: PcuMaxNoDLtbfInCHModification: OnlineRange: 1 –
9
MML default: 9Description:With this parameter you define the maximum number of TBFs
that a radio time slot can have in average, in a GPRS territory, in the downlink direction.
Related command(s): EEQ, EEORecommended value: default
For internal use only78 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Maximum Number of UL TBF (MNUL)
Q3 name: PcuMaxNoULtbfInCHModification: OnlineRange: 1 –
7
MML default: 7Description: With this parameter you define the maximum number of TBFs
that a radio time slot can have in average, in a
GPRS territory, in the uplink direction.Related command(s): EEQ, EEORecommended value: default.
For internal use only79 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Free TSL for CS Upgrade (CSU)
Q3 name: FreeTSLsCsUpgradeModification: OnlineRange: 0 -
10 (s)
MML default: 4Description: With this parameter you define a period following a
GPRS upgrade during which the probability for a GPRS downgrade in a BTS should be no more than 5%. Based on the given time and the size of a BTS (number of TRXs) the BSC defines a margin of idle TSLs
that is required as a condition for
starting a GPRS territory upgrade in the BTS. A GPRS upgrade may be done if the number of free TSLs
in a BTS is at least
equal to the defined margin still after the upgrade. Related command(s): EEM, EEORecommended value: default
For internal use only80 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Free TSL for CS Downgrade (CSD)
Q3 name: FreeTSLsCsDowngradeModification: OnlineRange: 0 -
100 (%)
MML default: 95Description: The parameter gives a target probability of TCH availability for circuit switched services in a BTS with GPRS territory. Based on the given probability and the size of a BTS (number of TRXs) the BSC defines a margin of idle TCHs
that it
tries to maintain free for the incoming circuit switched TCH requests in the BTS. If the number of idle TCHs
in the circuit
switched territory of a BTS decreases below the defined margin a GPRS territory downgrade is started. Related command(s): EEM, EEORecommended value: default
For internal use only81 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
BS_CV_Max
This parameter is used for 2 things:
1) It determines the start of the count-down procedure at the end of the UL TBF (GPRS and EGPRS):•
Before the count-down starts, new data arriving from upper layers are simply inserted into the existing TBF
•
After the count-down has started, new data arriving from upper layers require establishment of a new TBF
2) It impacts the implicit ack/nack
procedure (EGPRS only, see next slide)
For internal use only82 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
BS_CV_Max
EGPRS uses implicit ack/nack
procedure:
Transmitted blocks:
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12Received blocks:
1, 2, 3, 4, 5, , , 8, 9, , ,
BSS issues ack
message
here- - + +
Only 4 blocks in
ack
message
Blocks 1 –
5 are implicitly ack’ed. Blocks 10 –
12 aImplicitly nack’ed
For internal use only83 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
BS_CV_Max
Ack
message
transmitted
MS BSSTi
me
BS
_CV
_Max
For internal use only84 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
BS_CV_Max
Too low BS_CV_Max value:•
Unnecessary retransmission of blocks => significant reduced throughput
Too high BS_CV_Max value:•
Delayed retransmission of blocks
•
More TBFs
required if unsteady flow from upper layers•
=> slightly (?) reduced throughput
Default BS_CV_Max value is 6 (PA file parameter)Tests have shown BS_CV_Max = 11 gives good performanceMaybe handset dependent!
For internal use only85 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
QoS related parameters
DL HIGH PRIORITY SSS 1 ... 12 3
DL HIGH PRIORITY SSS 1 ... 12 6
DL HIGH PRIORITY SSS 1 ... 12 12
UL PRIORITY 1 SSS 1 ... 12 3
UL PRIORITY 2 SSS 1 ... 12 6
UL PRIORITY 3 SSS 1 ... 12 9
UL PRIORITY 4 SSS 1 ... 12 12
Parameter Range Default Valu
•Parameters in HLR GPRS subscription
For internal use only86 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
QoS in Scheduling: virtual time
Transmission turn
X X+1 X+2 X+3 X+4BPN
Gold, SSS = 2
Silver, SSS = 6
Best effort, SSS = 12
6 12
7
5
3
1
0 1
3
3
6
6 6
6
7 7
7
12 12 12
At each transmission turn: •The TBF with the lowest virtual time is transmitted. •The virtual time is then increased by its SSS•SSS depends on the user QoS
TSL
For internal use only87 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 4, 2010
Data KPI (measurement, formula, counter)
For internal use only88 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 5, 2010
Reporting Suite For Data Performance Monitoring
•
RS 226: Radio Performance•
RS 280: EDAP monitoring
•
RS 243: Gb
over FR monitoring•
RS 284: Gb
over IP monitoring
RS284 GboverIPRS226 EGPRS performance