dap configuration

For internal use only1 © Nokia Siemens Networks Sarachunt Somkliengcharoen / January 4, 2010

24 June 2010

GPRS / EDGE Workshop


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


GPRS – EDGE Theory Overview


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


(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


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


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

http://www.nokia.fi/puhelimet/puhelinmallit/cardphone20/

http://www.nokia.fi/puhelimet/puhelinmallit/n80/

http://www.nokia.fi/puhelimet/puhelinmallit/6230i/



(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


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


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



(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


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


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


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


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


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)


(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


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.


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


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.


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


PCU – Gb – Bearer Theory Overview


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


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


(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


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


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.


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


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


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


64 kbps channels 31 31 31 31PCU-T BSCE, BSC2, BSCi, BSC2i BTS 64 64 64 64


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


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


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


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


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

http://www.nokia.fi/puhelimet/puhelinmallit/9300i/


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


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


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


Parameter Setting & Definition


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


Territory Parameter Group


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.


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%


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.


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


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


Link Adaptation Parameter Group


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


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


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


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)



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.



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




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)


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




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)


Better throughputs overall, but very

unstable in low C/I conditions

No big differences between

different values of BLA

FTP DL 1Mb 2TSL


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.



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



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


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.


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


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


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.


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


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


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.


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.)


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


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


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


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


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.


UL Power Control Parameter Group


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.


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.


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.


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.


BSC Parameter Group


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


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.


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


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


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)


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


BS_CV_Max

Ack

message

transmitted

MS BSSTi

me

BS

_CV

_Max


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!


QoS related parameters

DL HIGH PRIORITY SSS 1 ... 12 3



UL PRIORITY 1 SSS 1 ... 12 3




Parameter Range Default Valu

•Parameters in HLR GPRS subscription


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


Data KPI (measurement, formula, counter)


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

dap configuration

Documents