b9_24_introduction to gprs and e-gprs qos monitoring 3fl11829abaa

8/13/2019 B9_24_Introduction to GPRS and E-GPRS QoS Monitoring 3FL11829ABAA

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All rights reserved. Passing on and copying of this document,

use and communication of its contents not permitted without

written authorization from Alcatel.

EVOLIUM Base Station SubsystemIntroduction to GPRS & E-GPRS QoS Monitoring /

B9

TRAINING MANUAL3FL11829ABAAWBZZA ed 1 January 2006


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Safety Warning

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2004 Alcatel. All rights reserved.

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5Introduction To GPRS & E-GPRS Quality of Service Monitoring /

B9All rights reserved 2005, Alcatel

PROGRAM

1 Role of the BSS in GPRS QoS Monitoring

2 Recalls on the Main BSS GPRS Telecom Procedures3 Description of the Main BSS GPRS QoS Counters and

Indicators

4 Detection of the Main BSS GPRS QoS Problems

5 Analysis of the Main BSS GPRS QoS Problems


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All rights reserved 2004, Alcatel

1 Role of the BSS in GPRS QoS monitoring


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1 Role of the BSS in GPRS QoS MonitoringSession Presentation

> Objective: to be able to describe the role of the BSS in the End-user GPRS QoS and the dependencies between Global

(BSS+GSS) and BSS GPRS QoS on one hand and betweenBSS GSM and GPRS QoS on the other hand

> Program:

1.1 Distinction between BSS/BSS+GSS/End-user GPRS QoS

1.2 Implementation of GPRS QoS profiles at BSS level

1.3 Source of information for GPRS QoS monitoring1.4 Dependencies between BSS GSM and GPRS QoS

1.5 Impact of GMM/SM signaling on BSS QoS interpretation

1.6 Indicators Classification


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1.1 Distinction between BSS/BSS+GSS/End-user GPRS

QoS


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1.1 Distinction between BSS/BSS+GSS/End-user GPRSQoSDifferent Levels of QoS GGSN

GPRSGPRS

BackboneBackbone

PacketPacket

DataData

NetworkNetwork

Gb

SGSN

A935

MFS

BSC

Ater

B

T

S

Abis

BSS

BSS+GSS QoS

Gn GiUmR

BSS QoS

End-user QoS

TETE

> 3 types of QoS are involved in the overall analysis of the GPRS QoS :

Radio QoS

It must be considered from the R interface to the Gb interface. It belongs mainly to the radio environment as wellas the proper functioning of the PCU implemented inside the BSS.

It is defined in terms of throughput, service precedence, RLC reliability mode, transfer delay.

GPRS QoS

It must be considered from the R interface (MS access to the GPRS) to the Gi interface (exit from the GPRSNetwork).

It includes the Radio QoS and the GSS QoS.

It is defined in terms of service precedence, transfer delay, mean and peak throughputs and reliability.

End-User QoS

This is the QoS as the user feels it.

It includes the GPRS QoS as well as the QoS of the external networks and their connection to the GPRS GSS. Even if it does not belong to the operator, it should still be monitored as it can generate customer complaints.


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1.1 Distinction between BSS/BSS+GSS/End-user GPRSQoSDependencies between QoS levels

End-user QoS

BSS+GSS QoS

BSS QoS

> A bad BSS GPRS QoS (Radio QoS) will lead to a bad GPRS QoS and a bad End-user QoS.

> A bad End-user performance can be due to a bad GSS behaviour without any BSS GPRS QoS degradation.

> A bad End-user QoS can also be due to a bad PDN performance.


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1.1 Distinction between BSS/BSS+GSS/End-user GPRSQoSImpact of UE

> Different data applications are multiplexed over the GPRS radio

layers: FTP, WEB/HTTP, WAP, MMS, etc

> Data applications have very different traffic characteristics

(amount of data, duration between LLC PDUs) leading to

different ways of triggering radio layers algorithms

> Therefore Parameters setting in the GPRS network will lead to

different performance according to the service

> A bad end-user QoS can also be due to the setting of TE protocol layers parameters which can not have optimal values to get thebest GPRS performance.


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1.1 Distinction between BSS/BSS+GSS/End-user GPRSQoSImpact of UE : example

> Data applications use TCP/IP protocol layers which have a

great impact on the end-user QoS

(*)

First IP router Last IP ro

GTP

relay

SNDCP

BSSGPRLC BSSGP

relay

relay

SNDCPPPP

FTP

TCP

IP

PPP

LLC

RLC

MAC

RF

MAC

RF

NS

L1

NS

L1

LLC UDP

IP-Gn

L2

L1

UDP

IP-Gn

L2

L1

IP

relay

IP

GTP

IP

relay

IP

relay

IP

UmR

Gb

Gn GiTE (PC,PDA )

MS

BSS

SGSN

GGSN

Possible repartition on the end to end path of the TCP flight si ze

TCP data segment

TCP acknowledgement

(*) this graphical representation is used toexpress the fact that many data segments arecurrently waiting to be transmitted on therepresented link and are stored in buffers of thedevice handling the link . It doesnt mean thatsimultaneous segments are being transmitted.

FTP above TCP/IP layers

> A bad end-user QoS can also be due to the setting of TE protocol layers parameters which can not have optimal values to get thebest GPRS performance.


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1.1 Distinction between BSS/BSS+GSS/End-user GPRSQoSUnderstand BSS GPRS QoS> GPRS QoS is not an isolated topic:

It is necessary to use GSM indicators in order to complete the

analysis of GPRS QoS

It is necessary to use GSM counters in order to complete the

analysis of the impact of GPRS traffic on GSM QoS

> The BSS QoS does not allow to have a complete

understanding of the end to end QoS seen by the user

Indeed, upper protocol layers (TCP for example) have a great

impact on the global QoS

The GSS also has a great impact on the global QoS


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1.2 Implementation of GPRS QoS profiles at BSS level


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Location services Traffic Conditions Itineraries Nearest Restaurant,

Cinema, Chemist,Parking;, ATM ...

Fun Games (Hangman, Poker, Quiz, ) Screen Saver Ring Tone Horoscope Biorhythm

MediaAlways-on

M-commerce

Mobile Office Voice (!)

E-mail Agenda IntraNet/InterNet Corporate Applications Database Access

Transportation Flight/train Schedule

reservation

Verticalapplication

Traffic Management

Automation

Mobile branches

Health

Music Downloading of

music files orvideo clips

News(general/specific) International/National News Local News Sport News Weather Lottery Results Finance News Stock Quotes Exchange Rates

Physical on-line shopping on-line food

Non physical on-line Banking Ticketing Auction Gambling Best Price e-Book

Directories Yellow/White Pages International Directories Operator Services

1.2 Implementation of GPRS QoS Profiles at BSS LevelData Services

> Different services can be found in the 3 categories:

Teleservices provide the full capabilities for communications by means of a terminal equipment, network functions andpossibly functions provided by dedicated centers.

Multimedia teleservices support the transfer of several types of information.

M-commerce:

Non-physical = electronic goods (e-banking, e-flight ticketing, etc).

Physical = electronic payment of physical goods (food, supplies, hardware, etc).

> Retrieval services

Provide the capability of accessing information stored in data base centers. The information is sent to the user on demand only. Anexample of one such service in the Internet's World Wide Web (WWW).

> Messaging services

Offer user-to-user communication between individual users via storage units with store-and-forward mailbox, and/or messagehandling (e.g., information editing, processing and conversion) functions;

> Conversational services

Provide bi-directional communication by means of real-time (no store-and-forward) end-to-end information transfer from user touser. An example of such a service is the Internet's Telnet application;

> Tele-action services

Characterized by low data-volume (short) transactions, for example credit card validations, lottery transactions, utility meterreadings and electronic monitoring and surveillance systems.

> Distribution services

Characterized by the unidirectional flow of information from a given point in the network to other (multiple) locations. Examples mayinclude news, weather and traffic reports, as well as product or service advertisements;

> Dispatching services

Characterized by the bi-directional flow of information from a given point in the network (dispatcher) and other (multiple) users.Examples include taxi and public utility fleet services;

> Conferencing services

Provide multi-directional communication by means of real-time (no store-and-forward) information transfer between multiple users.


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1.2 Implementation of GPRS QoS Profiles at BSS LevelQoS Requirements - Exercise

> Different applications require different QoS

Exercise: find qualitatively the QoS requirements of the following

data services

+: low sensitivity, ++: medium, +++: high

Service Tra nsfer Delay Throughput Relia b il i ty

web

video streaming

ftp

location based advertising

audio streaming

email

wap

fax

e-commerce

interactive gamesSMS

> Data applications have very different traffic characteristics (amount of data, duration between LLC PDUs) leading to differentways of triggering radio layers algorithms. This has a direct impact on the follow-up of some QoS indicators at OMC-R level:number of DL/UL TBF establishment requests, DL/UL TBF duration, coding scheme distribution.


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> 5 GPRS QoS attributes in the R97/98 standard:

Precedence Class: relative importance of service under

congestion; 3 values are defined Delay Class: total delay measured between the R or S point

and the Gi interface; 4 values are defined

Reliability Class: mainly linked to Ack / Not Ack modes at RLC

and LLC levels and within the backbone network; 5 values are

defined

Peak Throughput Class: measured at the Gi and R reference

points;9 values, ranging from 8 Kbit/s up to 2048 Kbit/s

Mean Throughput Class: measured at the Gi and R reference

points; 19 values, ranging from Best Effort up to 111 Kbit/s

1.2 Implementation of GPRS QoS Profiles at BSS LevelR97/98 GPRS QoS Profile

> Precedence classes: high, normal, low

> Delay classes: class 1 (average delay


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> ETSI R97 principles:

GPRS QoS is negotiated between the MS and the SGSN, at

PDP context activation

The BSS is not involved in QoS negotiation

No absolute QoS can be guaranteed by the BSS

The SGSN and the GGSN play the main role in QoS

management

> But the BSS should be able to do its best...

1.2 Implementation of GPRS QoS Profiles at BSS LevelETSI Principles


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GGSN

GPRSGPRS

BackboneBackbone

PacketPacket

DataData

NetworkNetwork

Gb

SGSN

A935

MFS

BSC

Ater

B

T

S

Abis

BSS

GPRS QoS

Gn GiUmR

Radio QoS

User QoS

TETE

1.2 Implementation of GPRS QoS Profiles at BSS LevelQoS Profile at BSS Level

> Throughput: not managed by Alcatel BSS. Best effort is supported.

> Service precedence: partly managed by Alcatel BSS.

> RLC reliability mode: managed by the BSS.> Transfer delay: not managed by Alcatel BSS. Best effort is supported.

> See next pages for details.


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1.2 Implementation of GPRS QoS Profiles at BSS LevelThroughput

> Throughput:

Defines the data throughput requested by the user

Specified on:

The DL path: in the DL BSSGP PDU header

The UL path: peak throughput class in Packet resource request(2-phase access)

Not taken into account by the BSS

The allocation strategy consists in trying to allocate to the MS as

many PDCHs as supported by its multislot class if known

> Throughput:

The PDCH available throughput (in terms of RLC/MAC blocks) is shared equally between all MSs allocated on it. TheBSS tries periodically to offer the best throughput to a TBF in case it has a sub-optimal allocation. It corresponds to thedirection of the bias and a better allocation is available.

The operator can limit the maximum number of PDCHs allocated to a TBF through the O&M configuration.

The maximum throughput that can be served to an MS is limited to n x 20 Kbit/s for a GPRS MS or n x 59.2 Kbit/s for anEGPRS MS, in case of good radio conditions (no retransmission), n being limited by the upper multislot class supportedby the network (n=5).


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1.2 Implementation of GPRS QoS Profiles at BSS LevelDelay

> Delay:

Defines the end-to-end transfer delay incurred in the

transmission of SDUs through the GPRS network

Specified on:

The DL path: through the PDU lifetime which indicates the latesttime at when the PDU must be completely transmitted

The UL path: peak throughput class in Packet resource request(2-phase access)

Best effort is supported by the BSS:

The PDU lifetime is taken into account for a DL LLC PDU

As many TSs as requested according to the MS Multislot Class

are allocated if possible

> Transfer delay:

This includes the radio channel access delay (on the uplink) or radio channel scheduling delay (on the downlink), the

radio channel transit delay (uplink and/or downlink paths) and the GPRS-network transit delay (multiple hops). It does notinclude transfer delays in external networks.

Delay is measured between the R or S (for MS) and Gi (for FS) reference points when applied to "MS to Fixed Station(FS)" or "FS to MS" transmissions.

The PDU lifetime is expected to be configured by the SGSN according to the GPRS transfer delay class of the associatedPDP context

In DL: case of unavailability of either traffic resources (TFI, TAI, throughput) or PDCH resources, DL TBF establishmentsrequests are queued and served according to the PDU lifetime.


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1.2 Implementation of GPRS QoS Profiles at BSS LevelReliability

> Reliability:

Defines the transmission characteristics that are required by an

application in terms of SDU loss probability, duplication of SDU,

mis-sequencing of SDU or corruption of SDU

Implemented at BSS level as RLC Acknowledged (Ack) mode or

RLC Not acknowledged (Nack) mode

Specified on

The DL path: in the DL BSSGP PDU header

The UL path: in Packet resource request (2-phase access)

Default mode: Ack


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1.2 Implementation of GPRS QoS Profiles at BSSLevel

Alcatel QoS Offer - R97/98 QoS Compliance

ETSI R97/98 QoS attributes Alcatel Of fer

Precedence classMean throughput

classDelay class Resulting QoS class

(4) Best Effort

1, 2 or 3

1,. 2 or 3

1,. 2 or 3

1,. 2 or 3

any

(3) Low priority

Normal, High priority

(2) Normal priority

(1) High priority

any

any

Best Effort

specified, except BE

specified, except BE

Best-Effort

Best-Effort

Best-Effort

Normal

Premium

Reliability class: as required by the MS

BE = Best-Effort

> The QoS attributes are associated with a PDP context performed by an R97/98 MS.

> The five QoS parameters of the standard define more than 60 combinations! This is too much and must be simplified:

Too complex to implement,

Many of the combinations have no meaning!

The standard "allows" simpler QoS implementations.

- = any value.

In green, the main criterion for the definition of the resulting QoS.

> Alcatel implementation: 3 QoS classes are defined:

Best effort: Inexpensive, comparable to the Internet (no commitment). Ideal for foraging on the internet.

Normal: Comparable to an intranet.

Premium: Expensive, high performance.


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> 4 UMTS QoS classes in the R99 standard (traffic

classes):

Conversational class

video conference

Streaming class

live video retransmission

Interactive class

web browsing

Background class

email, SMS

1.2 Implementation of GPRS QoS Profiles at BSS LevelR'99 UMTS QoS Classes

Delay

sensitiv

e

+

-

Data

Integrity

sensitiv

e

-

+

> Conversational class:

The most well known use of this scheme is telephony speech (e.g., GSM). But with the Internet and multimedia, a

number of new applications will require this scheme, for example voice over IP and video conferencing tools.

Real time conversation is always performed between peers (or groups) of live (human) end users. This is the onlyscheme where the required characteristics are strictly given by human perception.

> Streaming class:

When the user is looking at (listening to) real time video (audio) the scheme of real time streams applies. The real timedata flow is always aiming at a live (human) destination. It is a one way transport.

> Interactive class:

When the end user, that is either a machine or a human, is on line requesting data from a remote equipment (e.g., aserver), this scheme applies.

Examples of human interaction with the remote equipment are: web browsing, data base retrieval, server access.Examples of machines interaction with the remote equipment are: polling for measurement records and automatic database enquiries (tele-machines).

> Background class:

When the end user, that typically is a computer, sends and receives data files in the background, this scheme applies.

Examples are background delivery of E-mails, SMS, download of databases and reception of measurement records.


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1.2 Implementation of GPRS QoS Profiles at BSS LevelAlcatel QoS Offer - R97/98 QoS Mapping into R'99 QoS

Traffic handling priorityR'99 Traffic class R97/98 Bearer QoS class

Premium

Premium

Premium

Normal

Normal

conversational

streaming

interactive

interactive

interactive

-

-

1

2

3

Best Effortbackground -

> There is a mapping between R'99 Traffic class and Alcatel QoS

class

> The mapping of R97/98 QoS attributes to R'99 QoS is applicable in the following cases:

hand-over of PDP context from GPRS R97/R'98 SGSN to GPRS R'99 or UMTS SGSN.

when an R'99 MS performs a PDP context activation in an R'99 SGSN with an R'97/98 GGSN.

When GGSN respond to the PDP Context Activation, mapping of the changed R97/98 QoS attributes received from

the GGSN to R99 QoS attributes is performed in the serving SGSN.

when the SGSN has received an R97/98 QoS subscribed profile, but the MS is R'99.

> The mapping of R'99 QoS attributes to R'97/98 QoS is applicable in the following cases:

the PDP context is handed over from GPRS R'99 to R'97/R'98.

when an R'99 MS performs a PDP context activation in an R'99 SGSN while the GGSN is R'97/98.

In this case the SGSN shall perform mapping of the R99 QoS attributes to the R97/98 QoS attributes;

when the SGSN sends user data to the BSS for an R'99 MS.

when the SGSN has received R'99 QoS subscribed profile but the MS is R'97/98.

in the new SGSN, during an inter-SGSN RA_update procedure, or an inter-system change, on receipt of the R'99 QoS

attributes from the old SGSN.


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1.3 Source of information for GPRS QoS monitoring


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1.3 Source of Information for GPRS QoS MonitoringTrace User Data Transfer

> Transmission plane

MAC

GSM-RF

LLC

RLC

IP/X25

SNDCP

application

MS

MAC

UmMFS

RLC

relay

BSSGP

NS

L1bis

NS

L1bis

BSSGP

Gb

LLC

SGSN

SNDCP GTP

L2

L1

IP

UDP/TCP

relay

GSM-RFrelay

Abis/Ater

L1-GCHL2-GCH

L1-GCHL2-GCH

BTS

AirInterfacetraces

GCHtraces

Gbtraces

> Interfaces traces are of good complementary information but expensive:

used for problem investigation

used when lack of PM counters


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1.3 Source of Information for GPRS QoS MonitoringEnd-User QoS

> End-user performances are obtained through measurements

carried out for different end-user services:

Ping

FTP

WAP

WEB (HTTP)

Traces must be performed at both Air interface and Applicationlevels

> These performances must be interpreted with a maximum of

information concerning the context of the measurements Use of a database to register performance results

> FTP tests:

Static cell measurements:

DL transfer of an uncompressible file of 500 KB size UL transfer of an uncompressible file of 200 KB size

Drive measurements:

DL transfer of an uncompressible file of 1MB minimum size

UL transfer of an uncompressible file of 200 KB minimum size

> PING Tests:

Series of 100 pings

> HTTP tests:

Static cell and drive measurements:

HTTP browsing of an html page of 400 KB minimum size


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1.3 Source of Information for GPRS QoS MonitoringEnd-User QoS Measurements Results

> Applications server accessibility (PING)

Server accessibility success rate

Round Trip Time (RTT) in seconds per ping command

> FTP

FTP session success rate

Application layer throughput in kbit/s per file

> WAP

WAP gateway access time

WAP page download success rate

Application throughput

> HTTP (WEB) WEB page download success rate

Application throughput

> MMS tests:

MMS emission success rate

MMS notification success rate MMS reception success rate

MMS time to send

Time to receive the MMS notification

Time to retrieve the MMS

>Optional RLC/MAC statistics during end-user QoS tests:

CS distribution : % of CSx RLC blocks and total time of CSx usage

CS changes: number of CS changes per minute

Retransmissions: % of RLC blocks retransmitted

BLER: % of RLC blocks in error

> Usually QoS indicators giving throughput or time values are provided with 4 detailed indicators:

minimum

maximum

average

standard deviation


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1.3 Source of Information for GPRS QoS MonitoringGSS QoS

> Counters:

in the SGSN

in the GGSN

in the HLR

> Traces:

BSS-SGSN interface (Gb)

GGSN-PDN interface (Gi)

intra-GSS interface (Gn)


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1.3 Source of Information for GPRS QoS MonitoringBSS QoS

> Counters:

in the MFS (specific to GPRS)

in the BSC (in relation to GSM)

> Traces:

Air interface (Um)

Ater interface (GCH)

MFS-BSC interface (GSL)

BSS-SGSN interface (Gb)

Tool chain = OMC-R+NPA+RNO

Trace MS + Agi lent NITRO

Protocol analyzer + COMPASS


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1.3 Source of Information for GPRS QoS MonitoringBSS QoS Measurements Principles

BTSInternet/Intranet

SGSN GGSNMFSBSCFire-wall

OtherPLMNPacket domain

Core network

GnGbAterAbis

Physical layer

RLC/ MAC layer

IP layer

Appl ication layer SERVERe.g.

FTP, HTTPGPRSMS

Sagem

OT190

Measurement

Trace SW

Agilent

E6474A

Appl icati on

Presentation

Session

Physical

Transport

Data Link

OSI Layer

Network

LLC layer

BTSInternet/Intranet

SGSN GGSNMFSBSCFire-wall

OtherPLMNPacket domain

Core network

GnGbAterAbis

Physical layer

RLC/ MAC layer

IP layer

Appl ication layer SERVERe.g.

FTP, HTTPGPRSMS

Sagem

OT190

Measurement

Trace SW

Agilent

E6474A

Appl icati on

Presentation

Session

Physical

Transport

Data Link

OSI Layer

Network

LLC layer

Protocol

Analyzer

K1205

AMI CompassGNNettest

OMC-R network stat istics

with OMC-Rnetwork counters

Gb Statistics

GPRS Air

Interface

Statistics

>For the Air interface trace:

Use of a too old or too new mobile can be risky

Reference mobiles are Sagem (OT290), Motorola (T280), NOKIA ( 6230)Use of a PC preferably with Windows 2000

Use of the Agilent software E6474A Nitro

Use of end-user QoS monitoring tool (DEUTRIP, DMS)

>For the GCH, GSL, Gb interface trace:

Use of a protocol analyzer with the Alcatel BSCGP stack

The reference analyzer is Tektronix K1205 v2.40

Use of a post-processing tool

The reference tool is COMPASS GPRS


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1.4 Dependencies between BSS GSM and GPRS QoS


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1.4 Dependencies between BSS GSM and GPRS QoSImpacts

GSM QoS

GPRS QoS

> Bad radio conditions like coverage or interference problems degrading GSM QoS also provoke BSS GPRS QoS problems.

> Bad BSS GPRS performance is not always correlated to GSM QoS problems:

Congestion can be due to a lack of resource specific to GPRS. A low throughput can be due to a bad setting of radio algorithms specific to GPRS .

> On the other hand GPRS traffic can induce or worsen GSM QoS performance:

PS traffic can increase CS congestion.

PS signaling using CCCH channels can induce a PS AGCH and/or PCH overload and eventually an SDCCH congestion.


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Time allowed:

10 minutes

1.4 Dependencies between BSS GSM and GPRS QoSExercise

Among the following list of typical problems in aGSM network:

Find the ones having an impact on BSSGPRS QoS

Typical BSS GSM pr oblem Impact on BSS GPRS QoS

Coverage

Interference

path unbalanced at cell fringe

TRX HW degradation

Abis MW problem

A interface congestion

SDCCH congestion

TCH congestion

Rate of LU/call too high

Handover failure too high


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1.5 Impact of GMM/SM Signaling on BSS QoS InterpretationGMM/SM Signaling Load

> There are a lot of GPRS signaling message in case of:

cell update

RA update (Normal, Periodic)

> There are less GPRS signaling message in case of :

GPRS attach

GPRS detach

PDP context activation

PDP context de-activation

> BSS GPRS QoS indicators must be carefully interpreted knowing that TBFs are used for both data and signaling transfer.

> Gb traces might be needed for a better understanding of QoS problems.


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Alcatel 44




> This chapter is also valid for B7 release.


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Alcatel 45




> Traffic Load

> Quality Of Service

Evaluation of the rate of success or failure per interface : (Radio, AterMux, Gb)

or per telecom procedure:

TBF UL/DL establishment, UL/DL Data transfer, radio resource

allocation or re-allocation

> Resource Availability and Usage

Abis interface (abis nibbles)

AterMux interface (GCH, LapD) Gb interface (PVC, Bearer Channel)

GPU object (CPU and DSP usage)

B9


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Alcatel 46




BSCGP Interface

GB Interface

Control and Traffic

Channels

Ressource

Allocation

Data Transfer

TBF

Establishment

Traffic Load

Ressource

Allocat ion

Data Transfer

TBF

Establishment

Global QoS

DSP

CPU

Gb Interface

Ater Interface

Abis Interface

Resource

Availabil ity

GPRS

Indicators

B9

NewB9


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Alcatel 47


2 Recalls on the Main BSS GPRS TelecomProcedures

B9

> This chapter is a summary of GPRS basics. It is also valid for B7 release.


48/267


49/267

Alcatel 49



2.1 GPRS Logical Channels


50/267

Alcatel 50



2.1 GPRS Logical Channels

PDCH

Master PDCH Slave PDCH

PBCCH PCCCH

PDTCH PACCH

PTCH PTCCH

Primary MPDCH

PPCH PAGCH

Secondary MPDCH

physical channel

control channel

traffic channel

signaling associated control channel

logical channel category

logical channel


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Alcatel 51



2.2 TBF: Data Transfer Procedure between the MS and the

BSS

B9


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Alcatel 52



2.2 TBF Data Transfer Procedure between the MS and theBSSRadio Resources

> Temporary Block Flow (TBF): unidirectional flow of databetween the MS and the MFS for the transfer of one or more

LLC PDUs> Radio resources allocated to a TBF are:

DL TBF:

UL TBF:

PDCH 1

B0 B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 B11

PDCH 2

B0 B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 B11

PDCH 3

B0 B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 B11

TBF with TFI = 5 TBF with TFI = 17 TBF with TFI = 24

> A Temporary Block Flow is a temporary, unidirectional physical connection across the Um interface, between one mobile and theBSS. The TBF is established when data units are to be transmitted across the Um interface. It is released as soon as thetransmission is completed.


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Alcatel 53



2.2TBF Data Transfer Procedure between the MS and theBSSTBF Phases

> The TBF procedure can be split as represented below

> During an on-going TBF (progress) in one direction, a TBF inthe other direction can be established quicker than usually

establishment progress release

Radio resources to be

used during the data

transfer are reserved by

the BSS and areassigned to the MS

Data transfer through

RLC blocks

transmission

Radio resources are

freed


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Alcatel 54



> In order to establish a DL TBF faster the release of a UL TBF

can be delayed

T_DELAYED_FINAL_PUAN is the time during which a DL TBF

can be established using the UL TBF radio resources before theyare freed

UL TBF

2.2 TBF Data Transfer Procedure between the MS and theBSSUL TBF, Delayed Final PUAN without extended UL TBF

establishment progress release

T_DELAYED_FINAL_PUAN


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Alcatel 56



> The release of a DL TBF is delayed after all the DL RLC blocks

have been transferred in order to be able to:

establish a UL TBF faster

resume the DL data transfer (new LLC PDU coming from the

SGSN) without having to establish a new DL TBF

DL TBF

2.2 TBF Data Transfer Procedure between the MS and theBSSDL TBF, Delayed DL TBF Release

progress release

T_NETWORK_RESPONSE_TIME

TBF active TBF delayed


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Alcatel 57



> A DL TBF can be re-established faster during a short time after

a DL TBF release using the radio resources of the previous TBF

It is possible because the MS still monitors the radio resources

during timer T3192 after the DL TBF has been released

DL TBF

2.2 TBF Data Transfer Procedure between the MS and theBSSDL TBF, Fast Establishment

release

T3192

TBF active TBF delayed

Fast DL TBF

establishment

on PACCH

possible


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Alcatel 58



> After T3192, a DL TBF has to be established on Control

Channels:

faster during DRX_TIMER_MAX when the MS is in Non-DRX

mode

slower afterwards when the MS is in DRX mode

DL TBF

2.2 TBF Data Transfer Procedure between the MS and theBSSDL TBF, Establishment in DRX Mode

TBF release

DRX_TIMER_MAX

TBF active

TBF delayed

T3192

on PCH

or PPCH

of MS paging group

DL TBF establishment

possible

on AGCH

or

any PPCH


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Alcatel 59



2.3 Gb: BSSGP Protocol and Frame

B9


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Alcatel 60



2.3 Gb: BSSGP Protocol and FrameL1bis

> Bearer Channels

L1

NS (SNS)

NS (NSC)

BSSGP

MFS

L1

NS (SNS)

NS (NSC)

BSSGP

SGSN

Gb interface

PCM BC i

BC j

PCM

BC y

BC x

> The Gb physical interface is made up of one or more 64-Kbit/s channels on one or more physical lines at 2048 Kbit/s.

> Both individual 64-Kbit/s and n*64-Kbit/s channels are supported by the MFS.

> A Bearer Channel (BC) is an n*64-Kbit/s channel (1 n 31).

> NB: among the 16 PCM links offered per PCU, only 8 are dedicated to the Gb interface, 4 for the upload and 4 for thedownload. The maximum point-to-point transfer capacity over the Gb interface in one direction is then 31*64 Kbit/s*4 = 8192Kbit/s.


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Alcatel 61



2.3 Gb: BSSGP Protocol and FrameNetwork Service 1/3

> The Sub-Network Service (SNS) sub-layer is dependent on the

transmission network and manages Permanent Virtual

Channels (PVCs)

L1

NS (SNS)

NS (NSC)

BSSGP

MFS

L1

NS (SNS)

NS (NSC)

BSSGP

SGSN

Frame Relay NetworkPVCa

DLCIx

PVCm

DLCI

PVCb

DLCI

y

PVCn

DLCI

Gb interface

> Concept of PVC:

A PVC is a synchronous access line, semi-permanent connection.

The PVC allows the multiplexing on a BC. It is not an end to end link between the MFS and the SGSN.

At MFS side a PVC is identified by its Data Link Connection Identifier (DLCI) which is independent from the one definedat SGSN side. DLCI 0 is used for signaling.

There is one PVC per BC.

> The SNS layer, layer 2.1 in the OSI model, offers the Frame Relay technology. The NSC layer, layer 2.2 in the OSI model,offers the point to point data transfer in both directions.

> The PVC standards are not specific to GPRS. Please refer to the Frame Relay Forum organization, the ITU-T and ANSI(T1S1.1 workshop) specifications.


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Alcatel 63



2.3 Gb: BSSGP Protocol and FrameNetwork Service 3/3

> Concept of NSE:

A Network Service Entity (NSE) groups several NS-VCs (at least

2 NS-VCs per NSE) = the NSE corresponds to the resources of

one GPU

The concept of NSE is useful for the load sharing between the

different NS-VCs: the NS-VCs of the NSE are shared by the BVC

associated to the NSE

The NSE is identified by an NSEI which has an end-to-end

significance over the Gb interface

NSVC

NSVCi=11

NSVC

NSVCi=12L1

NS (SNS)

NS (NSC)

BSSGP

PCU

NSE

NSEi = 1

> Note: for MM purposes, the SGSN needs a 1:1 correspondence between the NSEI and the RAI.

Physical layer

SNS sub-layer

NSC sub-layer

BVCBSSGP layer

Cell

BSS

BVC

Cell

2 Mbit/s

BC BC

PVC PVC

NS-VC NS-VC

NSE

BVC

Cell

BVC

Cell

2 Mbit/s

BC BC

PVC PVC

NS-VC NS-VC

NSE


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Alcatel 64



SNS

NSC

BSSGP

SGSN

2.3 Gb: BSSGP Protocol and FrameBSSGP

> BSSGP Virtual Connection (BVC): end to end link between the

MFS and the SGSN

L1

SNS

NSC

BSSGP

MFS

L1

Gb interface

NSVC

BVCi=1

BVCi=2

BVCi=n BVCi=1

BVCi=2

BVCi=n

> Two types of BVC:

point-to-point BVC dedicated to the PS traffic of one cell (BVCi 0).

signaling BVC (BVCi=0) which is the signaling circuit of all the point to point BVCs of one NSE (GPU).

> For NM reason, the duplet BVCi/NSEi must be unique within an SGSN.

> To activate a new cell in an SGSN, it is only needed to add a new BVCi in an NSEi. No update of the NSEi information isnecessary.


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Alcatel 65



NSE2

SGSN

NSE1NSE1

NSE2

F.RF.RNetworkNetwork

PCM

2.3 Gb: BSSGP Protocol and FrameGb Interface - Manageable Entities

PCM

PCM

BVCI=2

BVCI=

1BVCI=3

BVCI=5

BVCI=

6

BVCI=

4

BSC1

BSC2

GPRS Core Network sideBSS side

BC PCMBCPVC

BC BCPVC

NSVC1

NSVC2

PCM

PCM

PCM

BC PCMBCPVC

BC BCPVC

NSVC3

NSVC4

BVCI=2BVCI=2

BVCI=1BVCI=1

BVCI=3BVCI=3

BVCI=5BVCI=5

BVCI=4BVCI=4

BVCI=6BVCI=6

> Dimensioning rules:

Gb inter face

Max. number of Gb interface physical links

per GPUnGb nGb+ nAter(mux)16 where nAter(mux)

Max. number of Frame Relay bearer

channels per physical link31

Max. number of Frame Relay bearer

channels per GPU board124

Max. number of BVCs per GPU board 265 Limit due to the number of cells per BSS(264) + one signalling BVC (1)

Number of signalling BVCs per GPU 1 1 NSE is defined per GPU

Ater inter face

Maximum number of 64 kbit/ s signalling

channels (GSL) per GPU

4

Number of Ater(mux) PCM links between

one GPU and one BSC

nAte r(m u

x)

nGb+ nAtermux16

Atermux sharing granularity for PS traffic g g can be set to:100 % AterMux, or

75 % AterMux, or

25 % AterMux, or

12.5 % Atermux for GPRS traffic

Max. number of BSSs per MFS 22

Max. number of GPUs per MFS 30

Max. number of BSS per GPU board 1

Max. number of cells per MFS 20 00

Max. number of TBFs per GPU 96 0

Maximum number of GPU boards per BSS 6


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Alcatel 66



2.3 Gb: BSSGP Protocol and FrameGb Interface - Protocol Model and Entities

SGSNPacket Control Unit function

(PCU)

BSS GPRS Protocol

(BSSGP)BSS GPRS Protocol

(BSSGP)

Network Service Control

(NSC)Network Service Control

(NSC)

BVCI=BVCI=

22BVCI=BVCI=

11BVCI=3BVCI=3

BVCI=5BVCI=5

BVCI=BVCI=

66

BVCI=BVCI=

44

BSC1

BSC2

GPRS Core Network sideBSS side

Sub-Network Service

(SNS)

Physical layer

Sub-Network Service

(SNS)

Physical layer

Frame Relay

BVC

NS-VCNSE

PVCBC


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Alcatel 67



2.3 Gb: BSSGP Protocol and FrameBSSGP Frame

> One BSSGP PDU includes one and only one LLC PDU

GPRS Traffic or signalingTLLIBVCI

LLC frame

BSSGP frame

LLC header

BSSGP header

LLC payload

> In case of data traffic the LLC PDU contains an SNDCP PDU.

> In case of signaling, the LLC PDU contains a GMM or an SM message.


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Alcatel 68


3 Description of the Main BSS GPRS QoS Countersand Indicators B9


69/267

Alcatel 69



3 Detection of the Main BSS GPRS QoSCounters/IndicatorsSession Presentation

> Objective: to be able to interpret the BSS GPRS QoS indicators

attached to each BSS GPRS procedure or algorithm having an

impact on QoS and to interpret the BSS GPRS PM counters

used in the computation formulae of QoS indicators

> Program:

3.1 Data Transfer Establishment

3.2 Data Transfer Progress

3.3 Data Transfer Release

3.4 MS Sessions / Transfers

3.5 Resource Usage

3.6 CS and MCS Adaptation

3.7 Cell Reselection

B9


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Alcatel 70


3 Detection of the Main BSS QoSCounters/Indicators

3.1 Data Transfer Establishment


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Alcatel 71



3.1 Data Transfer EstablishmentTBF Establishments

Data Transfer

establishment

UL TBF establishment DL TBF establishment

MS in PIM MS in PTM MS in PIM MS in PTM

MS in MM Ready s tate MS in MM Standby s tateMS in MM Ready s tate

on CCCH on PCCCH

2-Phase 2-Phase

on CCCH on PCCCH

Non-DRX Non-DRX

UL TBF

running

DL TBF

running

T3192

running

1-Phase1-Phase

PS Paging

DRX DRX

> There are 5 types of UL TBF establishment:

1. 1-phase access on CCCH : when the MS is in Packet Idle Mode and no PCCCH is available in the cell and the MS does

not need more than 1 PDCH and wants to transfer blocks in RLC acknowledge mode.

2. 2-phase access on CCCH : when the MS is in Packet Idle Mode and no PCCCH is available in the cell and the MSneeds more than 1 PDCH or wants to transfer blocks in RLC unacknowledge mode.

3. 1-phase access on PCCCH : when the MS is in Packet Idle Mode and a PCCCH is available in the cell and the MSdoes not need more than 1 PDCH and wants to transfer blocks in RLC acknowledge mode.

4. 2-phase access on PCCCH : when the MS is in Packet Idle Mode and a PCCCH is available in the cell and the MSneeds more than 1 PDCH or wants to transfer blocks in RLC unacknowledge mode.

5. During a DL TBF: when the MS is in Packet Transfer Mode in DL.

> There are 6 types of DL TBF establishment:

1. On CCCH DRX mode: when the MS is in Packet Idle Mode and no PCCCH is available in the cell and the MS islistening to all PCH channels of its CS paging group.

2. On CCCH Non-DRX mode: when the MS is in Packet Idle Mode and no PCCCH is available in the cell and the MS islistening to all AGCH channels.

3. On PCCCH DRX mode: when the MS is in Packet Idle Mode and a PCCCH is available in the cell and the MS islistening to all PPCH channels of its PS paging group.

4. On PCCCH Non-DRX mode: when the MS is in Packet Idle Mode and a PCCCH is available in the cell and the MS islistening to all PPCH channels of its PCCCH channel.

5. During a UL TBF: when the MS is in Packet Transfer Mode in UL.

6. When T3192 is running: when a DL TBF has been released at the MS side and before the previously used radioresources are released (at T3192 expiry).


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Alcatel 72



P49

3.1 Data Transfer EstablishmentUL TBF Establishment 1-Phase Access on CCCH,Success

MS BTS BSC MFS

TA calculation

RACH Channel request (TA)

(EGPRS Packet)

Channel request

AGCH

Immediate assignment

Channel assignment UL (IA)PDCH, TFI, USF, TAI, TA, CS

(MCS, EGPRS window size)MS switches

on assigned

PDCH USF Scheduling

PDTCH

USF Scheduling

RLC data block

PACCH

Packet UL Ack/Nack

PDTCH

TLLI, TFI

T_USF_Scheduling_AGCH

expiry

P62c

P30cContention

resolution

T_GPRS_ASSIGN_AGCH

RLC data block

TLLI, TFI

Packet UL Ack/Nack

P62d

GPRS EGPRS

P30d

GPRS EGPRS

GCH allocation

Channel required

(TA)

Imm. assign. command

> In case a Channel Request or an EGPRS Packet Channel Request is received from the mobile station, an ImmediateAssignment message is sent to the MS assigning the radio resources.

In case a Channel Request is received on a RACH, the BSS does not know the multislot class of the MS.Consequently, the Alcatel BSS assigns only one PDCH to the MS.

In case an EGPRS Packet Channel Request message is received from the mobile station, the EGPRS multislot class ofthe MS is known by the BSS. However only one PDCH is allocated due to the limitation of the Immediate Assignmentmessage.

if the PDCH is allocated on a non-EGPRS capable TRX an Immediate Assignment message in GPRS mode issent to the MS including the PDCH id, the USF value, the TFI value, the TAI value, the TA value, and the GPRScoding scheme to be used.

If the PDCH is allocated on an EGPRS capable TRX, an Immediate Assignment message in EGPRS mode issent to the MS including the PDCH id, the USF value, the TFI value, the TAI value, the TA value and theEGPRS modulation and coding scheme to be used.

> Timers

T_USF_scheduling_AGCH: Time between the sending of the Assignment Command message to the BTS and thescheduling of the first UL block on the PDCH. This internal MFS timer is always expiring in order to leave time to theMS to switch from a CCCH to a PDCH time slot.

T_GPRS_ASSIGN_AGCH T_USF_scheduling_AGCH: Started at T_USF_scheduling_AGCH expiry, stopped whenreceiving the first UL block from the MS.

T_GPRS_ASSIGN_AGCH = 0.8 s (default value) but computed as a function of the CCCH configuration in thecell. It cannot be set at the OMC-R level.

T_USF_scheduling_AGCH = 0 ms (default value). It cannot be set at OMC-R level.

> T_GPRS_ASSIGN_AGCH" is the HMI name of "T_ul_assign_ccch" present in BSS telecom parameters catalogue

> A contention resolution procedure is used in order to avoid that two MS sending a Channel Request at the same time use thesame allocated radio resource to send data.

Each MS sends its TLLI in the first RLC Data Block.

The TLLI of the MS chosen by the BSS is present in the Packet UL Ack/Nack from the MFS.

The other MS will stop using the radio resource when receiving the Packet UL Ack/Nack with another TLLI .


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Alcatel 73



3.1 Data Transfer EstablishmentUL TBF Establishment 2-Phase Access on CCCH,Success

MS BTS BSC MFS

RACH

Channel request

(TA)

(EGPRS Packet)

Channel request

AGCHImmediate assignment PDCH id, TBF starting time,

TA, 1 (multiple) block(s)

MS switches

on assigned

PDCHs

PACCHPacket resource request

Packet UL assignmentPACCH

Packet resource request

Packet UL assignmentTLLI, PDCHs, USFs, TFI, TAI, TA,

CS

(MCS, EGPRS window size)PDTCHUSF Scheduling USF Scheduling

TLLI, MS Radio Access Capability, QoS

(Additional Radio Access Capability)

RLC data block

PDTCH

P49

T_GPRS_ASSIGN_AGCH

T_ACK_WAIT

Contention

resolution

RLC data block

MS switches

on allocated

RLC block(s)

T3168

P62c P62d

GPRS EGPRS

P30c P30d

GPRS EGPRS

GCH allocation

GCH allocationTA calculation

Channel required

(TA)

Channel assignment UL (IA)Imm. assign. command

> A 2-phase access is initiated in one of the following cases:

When a GPRS MS wants to use the TBF to send user data in RLC unacknowledged mode.

When a GPRS or EGPRS MS wants to precise QoS parameters (e.g., Peak_Throughput_Class, Radio_Priority).

When a GPRS MS wants to provide the BSS with its multislot class in case of an uplink access done on CCCH.

When an GPRS MS wants to establish the TBF to send user data in RLC acknowledged mode and the amount of data tosend takes more than 8 RLC/MAC blocks (Note 1 and Note 2).

If the EGPRS PACKET CHANNEL REQUEST is not supported in the cell (Note: the Alcatel BSS always supports theEGPRS PACKET CHANNEL REQUEST), when an EGPRS MS wishes to send user data or signaling data.

If the EGPRS PACKET CHANNEL REQUEST is supported in the cell, when an EGPRS MS wants to use the TBF tosend user data in RLC unacknowledged mode.

If the EGPRS PACKET CHANNEL REQUEST is supported in the cell, when an EGPRS MS wants to establish the TBFto send user data in RLC acknowledged mode and the amount of data to send takes more than 8 RLC/MAC blocks (Note3 and Note 4).

Note 1: The number of blocks must be calculated assuming channel coding scheme CS-1.Note 2: The mobile station can also request a 1-phase access.Note 3: The number of blocks must be calculated assuming modulation and channel coding scheme MCS-1.Note 4: If the cell is EGPRS capable, the mobile station can also request 1-phase access.

> The MS Radio Access Capability IE includes the Multislot class of the MS as well as the QoS required for the transfer

> Timers

T_GPRS_ASSIGN_AGCH, controls the duration between (EGPRS Packet) Channel Request message and the UL radioblock allocated to the MS.

T_ACK_WAIT: Started when the first UL block is scheduled to the MS, stopped when receiving the first UL block.

T_ACK_WAIT = 1.2 s (default value). It cannot be set at OMC-R level.

T3168: MS timer started when sending the Packet Resource Request message and stopped when receiving the PacketUL Assignment. It is broadcast in the SI13 message.

T3168 = 1 s (default value). It can be set at the OMC-R level but 1 s is the minimum value.

> .


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Alcatel 74



3.1 Data Transfer EstablishmentUL TBF Establishment 1-Phase Access on PCCCH,Success

MS BTS BSC MFS

TA calculationPRACH (4 A.B.)

(EGPRS)

Packet Channel request

MS switches

on assigned

PDCHs

Packet UL assignment

PAGCH


PDCHs, USFs, TFI, TAI, TA, CS (MCS, EGPRS

window size)

PDTCHUSF Scheduling USF Scheduling

RLC data block

T_ACK_WAIT

PDTCH

RLC data block

Contention

resolution

TLLI, TFI

PACCH

Packet UL Ack/Nack

TLLI, TFI

Packet UL Ack/Nack

(EGPRS)


(TA)

(EGPRS) Multislot class

P30a P30d

GPRS EGPRS

P62a P62d

GPRS EGPRS

GCH allocation

(EGPRS)


(TA)

> Possible causes for the one phase access for GPRS:- 1-phase access (MS multislot class provided)- Short access (less than 8 RLC blocks)

- Paging response- Cell update- MM procedures (GPRS Attach, GPRS Detach, RA update)- Single block without TBF establishment

- Note: The access indicating Single Block Without TBF Establishment is supported by the Alcatel BSS: such an access isused by the MS to report a Packet Measurement Report message or a Packet Cell Change Failure message in PacketIdle Mode

> Possible causes for the one phase access for EGPRS:- 1-phase access- Short access- signaling

> A EGPRS mobile provides both its GPRS multislot class and its EGPRS multislotclass. If the TBF can not be established inEGPRS mode it will then be established in GPRS mode if possible. In this case the EGPRS multislot class is used by the BSS toallocate the corresponding number of PDCHs. If the GPRS multislot class is higher than the EGPRS one then the TBF is acandidate for a subsequent radio resource re-allocation to extend the number of PDCHs.


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Alcatel 75



3.1 Data Transfer EstablishmentUL TBF Establishment 2-Phases Access on PCCCH,Success

MS BTS BSC MFS

TA calculation

MS switches

on assignedPDCHs

PACCHPacket resource request


PACCHPacket UL assignment

TLLI, PDCHs, USFs, TFI, TAI, TA,

CS(MCS, EGPRS window size)PDTCH

USF Scheduling USF Scheduling

Packet resource requestTLLI, MS Radio Access Capability, QoS

(Additional Radio Access Capability)

T_ACK_WAIT

Contention

resolution

RLC data block

PDTCH

RLC data block

MS switches

on allocated

RLC block(s)

PRACH (4 A.B.)

(EGPRS)



PAGCH


T_UL_Assign_PCCCH

PDCH id, TBF starting time, TA, 1(multiple) block(s)


T3168

P62a P62d

GPRS EGPRS

P30a P30d

GPRS EGPRS

PDCH & GCH

allocation

(EGPRS)


(TA)

(EGPRS)


(TA)

> Timer: T_UL_ASSIGN_PCCCH controls the duration between (EGPRS) Packet Request message and the UL radio blockallocated to the MS.

T_UL_ASSIGN_PCCCH = 0.4 s (default value). It can be set at the OMC-R level.

> 2-phase access is used when the MS wants specific QoS attribute values to be taken into account (e.g., RLC Nack mode).


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Alcatel 76



3.1 Data Transfer EstablishmentUL TBF Establishment during a DL TBF, Success

MS BTS BSC MFS

P30b

T_ACK_WAIT

DL transfer

RLC data block, pollingRLC data block

PDTCH

Packet DL Ack/Nack

PACCH(EGPRS) Packet DL Ack/Nack with Channel request


PACCH


PDCHs, USFs, TFIUL,TAI, CS (MCS, EGPRS window size)

P62b

T3168

PDTCH


RLC data block

PDTCH

RLC data block

GPRS EGPRS

GPRS EGPRS

GCH allocation

> This scenario corresponds to a UL TBF establishment in PTM without re-allocation of the on-going DL TBF.

> The Packet UL Assignment message is repeated N_SIG_REPEAT times because if the MS has not decoded the Packet UL

Assignment then the MS tries again to establish the UL TBF only after T3168 expiry. N_SIG_REPEAT = 1 (default value). It cannot be set at the OMC-R level. Therefore the Packet UL Assignment is sent 2

times in a row.


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Alcatel 77



Time allowed:

30 minutes

3.1 Data Transfer EstablishmentUL TBF Establishment, Exercise

Exercise 1: Identify the type of UL TBFestablishment procedure among the providedtraces 1, 2, 3, 4, 5

Exercise 2: Using the trace 2 , find how manyTBFs are established and when?

Exercise 3: Using the trace 2, identify thevalues of:

TFIUL TFIDL PDCHs allocated for the UL TBF

B9


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Alcatel 78



3.1 Data Transfer EstablishmentUL TBF Establishment, Failures

UL TBF establishment FAILURE

BSS Resource

Congestion Radio pb BSS pb Gb pb

Radio

congestion

GPU DSP

congestion

Ab is

congestion

GPU with CPU

overload

B9

Ater

congestion

Too many TBF

DSP with CPU

in load state

NewB9

NewB9

NewB9

> Note:GPU congestion means that the maximum capacity of at least one DSP on the GPU is reached in terms of resourcesGCH and/or PDCH

A lack of Ater resources occurs when there is not enough Ater nibbles to serve the UL TBF request.A lack of Abis transmission resources occurs when there is not enough Abis nibbles to serve the UL TBF request.


79/267

Alcatel 79



3.1 Data Transfer EstablishmentUL TBF Establishment, Failures, BSS ResourceCongestion

MS BTS BSC MFS

RACH

(EGPRS Packet)

Channel request

AGCH

Immediate assignment rejectImm. assign. command

(Imm. assign. Reject) Wait indication

No resource available

(radio+Ab is+Ater+Toomany TBF+DSP+

GPU+GPU-CPU)

P27+P105j+P105h+P10

5l+P204+P105d+P105f(EGPRS)

Packet Channel

request

PAGCH or PACCH

Packet access reject Packet access reject

Wait indication

or Packet resource request

or Packet DL Ack/Nack with

Channel request



Channel request

Channel request (TA)Channel required

(TA)

(EGPRS)


(TA)



Channel request

(EGPRS)


(TA)

Channel assignment UL

(Imm. assign. Reject)

Packet access reject

B9

No resource available

(radio+Abis+Ater+Toomany TBF+DSP+

GPU+GPU-CPU)

Modified

B9

Modified

B9

> The first scenario corresponds to:

the impossibility to allocate the resources for a UL TBF establishment 1-phase access on CCCH.

the impossibility to allocate the UL block(s) for a UL TBF establishment 2-phase access on CCCH.

> The second scenario corresponds to:

the impossibility to allocate the resources for a UL TBF establishment 2-phase access on CCCH.

the impossibility to allocate the resources for a UL TBF establishment 1-phase access on PCCCH.

the impossibility to allocate the UL block(s) or the resources for a UL TBF establishment 2-phase access on PCCCH.

the impossibility to allocate the resources for a UL TBF establishment during a DL TBF.


80/267

Alcatel 80



3.1 Data Transfer EstablishmentUL TBF Establishment on CCCH, Failures, Radio

MS BTS BSC MFS

RACHChannel request + TA

(EGPRS Packet)

Channel request

AGCHImmediate assignmentPDCH, TFI, USF, TAI, TA, CS

(MCS, EGPRS window size)

USF Scheduling

PDTCH

USF Scheduling

RLC data block

PDTCHT_GPRS_ASSIGN_AG

CH expiryP28


PACCH


TLLI, PDCHs, USFs, TFI, TAI, TA,CS

(MCS, EGPRS window size)PDTCHUSF Scheduling USF Scheduling

T_ACK_WAI

T expiry

P28

Channel required

(TA)Channel assignment UL (IA)

Imm. assign. command


a radio failure occurring during a UL TBF establishment 1-phase access on CCCH.


a radio failure occurring during a UL TBF establishment 2-phase access on CCCH.

> If the contention resolution fails, the MS will try to establish the UL TBF up to 4 times.

> The radio problems counted are usually due to interference or bad coverage

but Abis microwave transmission problems or some BSS problems (RSL overload) can be counted as radio problems.


81/267

Alcatel 81



3.1 Data Transfer EstablishmentUL TBF Establishment on PCCCH, Failures, Radio

MS BTS BSC MFS

PRACH (4 A.B.)

(EGPRS)

Packet Channel

request


PAGCH


PDCHs, USFs, TFI, TAI, TA, CS (MCS, EGPRSwindow size)


P28T_ACK_WAI

T expiry


PDTCH

RLC data block

Packet UL assignmentPACCH

Packet UL assignmentTLLI, PDCHs, USFs, TFI, TAI, TA, CS

(MCS, EGPRS window size)


P28T_ACK_WAI

T expiry

(EGPRS)


(TA)

(EGPRS)


(TA)


a radio failure occurring during a UL TBF establishment 1-phase access on PCCCH.


a radio failure occurring during a UL TBF establishment 2-phase access on PCCCH.




82/267

Alcatel 82



3.1 Data Transfer EstablishmentUL TBF Establishment during a DL TBF, Failures, Radio

MS BTS BSC MFS

P28

DL transfer / Active or Delayed phase

RLC data block, pollingRLC data block

PDTCH

Packet DL Ack/Nack

PACCH(EGPRS) Packet DL Ack/Nack with Channel request


PACCH

Packet UL Assignment

PDCHs, USFs, TFIUL,TAI, CS (MCS, EGPRS window size)

T3168

PDTCH


T_ACK_WAI

T expiry

> If a DL TBF re-allocation is triggered upon a UL TBF establishment and if the DL TBF re-allocation fails due to a radio problemthen counter P28 is also incremented.




83/267

Alcatel 83



> Problem at Gb interface level

When the CELL is in the operational state disabled in the BSS

O&M problem

> Problem at BSS level

which is not linked to Congestion, Radio, Gb no specific counter

3.1 Data Transfer EstablishmentUL TBF Establishment, Failures, Gb, BSS

MS MFS SGSN

>

Cell identity

Cell BVC

unavailable

P66

> A problem at BSS level can be linked to a Hardware or a Software failure .


84/267

Alcatel 84



3.1 Data Transfer EstablishmentDL TBF Establishment on CCCH, MS in Ready State

MS BTS BSC MFS LLC PDU

PDCH, TFI, TAI, (EGPRS)Immediate assignment

PCH/AGCH (DRX/Non-DRX)

Packet DL assignment, polling

PDCHs, TFI, TAI, (EGPRS window size)PACCH

Packet DL assignment

PACCH (4 A.B.)

Packet control AckPacket control AckTA calculation

Timing Advance / Power control

PACCH

TA / PC

PDTCH

RLC data block

MS

switches

on

assigned

PDCH

P91f,

P91c

T3190

t_assign_agch_pacc

h

t_assign_pch_pacch

expiry & restart

P90f,

P90c

P91g

GPR

SEGPR

S

P90g

GPR

S EGPR

S

P53c,

P49

GCH allocation

Channel assignment UL (IA)Imm. assign. command

> If the MFS does not receive the Packet Control Ack message from the MS:

it sends again the Packet Downlink Assignment message up to MAX_GPRS_ASSIGN_PCH_RETRANS if the MS is inDRX mode or up to MAX_GPRS_ASSIGN_AGCH_RETRANS if the MS is in Non-DRX mode.

if the Maximum number of retransmission of Packet Downlink Assignment message is reached then the MFS restartsthe whole DL TBF establishment procedure up to MAX_DL_RETRANS times.

MAX_GPRS_ASSIGN_PCH_RETRANS = 3 (default value)

MAX_GPRS_ASSIGN_AGCH_RETRANS = 3 (default value)

MAX_DL_RETRANS = 3 (default value)

The other establishment attempts of the same TBF are not counted, only the first attempt is counted.

> Timers

T_GPRS_ASSIGN_AGCH: controls the reception of the Packet Control Ack message from the MS in Non-DRX mode.

T_GPRS_ASSIGN_AGCH = 0.8 s (default value) but computed as a function of the CCCH configuration in thecell. It cannot be set at the OMC-R level.

T_GPRS_ASSIGN_AGCH" is the HMI name of "T_ul_assign_ccch" described in the BSS telecom parameters

catalogue.

T_GPRS_ASSIGN_PCH: controls the reception of the Packet Control Ack message from MS in DRX mode.

T_GPRS_ASSIGN_PCH = 1.4 s (default value) but computed as a function of the BS_PA_MFRMS CCCHparameter in the cell. It cannot be set at the OMC-R level.

T_GPRS_ASSIGN_PCH" is the HMI name of "T_dl_assign_ccch" described in the BSS telecom parameterscatalogue.

t_assign_agch_pacch: is the time the MFS waits for the Packet Control Ack message after having sent the PacketDownlink Assignment message to the MS in Non-DRX mode before repeating the Packet Downlink Assignmentmessage.

Its value is computed as T_GPRS_ASSIGN_AGCH / (MAX_GPRS_ASSIGN_AGCH_RETRANS + 1).

t_assign_pch_pacch: is the time the MFS waits for the Packet Control Ack message after having sent the PacketDownlink Assignment message to the MS in DRX mode before repeating the Packet Downlink Assignment message.

Its value is computed as T_GPRS_ASSIGN_PCH / (MAX_GPRS_ASSIGN_PCH_RETRANS + 1).

T3190: if this timer expires, the MS returns into Packet Idle Mode.

T3190 = 5s (default value).


85/267

Alcatel 85



3.1 Data Transfer EstablishmentDL TBF Establishment on PCCCH , MS in Ready State

MS BTS BSC MFS LLC PDU

PPCH

(first/paging group)


PDCHs, TFI, TAI, (EGPRS window size)


PACCH (4 A.B.)

Packet control AckPacket control AckTA calculation

Timing Advance / Power control

PACCH

TA / PC

PDTCH

RLC data blockT3190

P90d,

P90a

MS

switches

on

assigned

PDCH

T_ACK_WAIT

T_ACK_WAIT_DRX_PCCCH

P91g

GPRS

EGPRS

P91d,

P91a

P90g

GPRSEGPRS

GCH allocation

> If the MFS does not receive the Packet Control Ack message from the MS:

the MFS restarts the whole DL TBF establishment procedure up to MAX_DL_RETRANS times.

MAX_DL_RETRANS = 3 (default value) The other establishment attempts of the same TBF are not counted, only the first attempt is counted.

> Timers

T_ACK_WAIT: controls the reception of the Packet Control Ack message from the MS in Non-DRX mode.

T_ACK_WAIT = 1.2 s (default value). It cannot be set at the OMC-R level.

T_ACK_WAIT_DRX_PCCCH: controls the reception of the Packet Control Ack message from the MS in DRX mode.

T_ACK_WAIT_DRX_PCCCH = 2.5 s (default value). It cannot be set at the OMC-R level.

T3190: if this timer expires, the MS returns into Packet Idle Mode.

T3190 = 5 s (default value)


86/267

Alcatel 86



T3190

PACCHTA/PC

TA/PC

PDTCHRLCdatablo

ckRLCdatablo

ckPACCHTA/PC

TA/PC

PDTCHRLCdatablo

ckRLCdatablo

ck

3.1 Data Transfer EstablishmentDL TBF Establishment during a UL TBF

MS BTS BSC MFS

UL transfer

PacketDLassignment

PACCH

PacketDLassignment,po

lling

PDCH(s),TFIDL,TA

I,(EGPRS

window size)

P91b

P90b

T_ACK_WAITPacketcontrolAckPacketcontrolAck

RRBP

LLC PDU

PDTCHRLCdatablo

ck

RRBP

+

40 ms

GCH allocation

> This scenario corresponds to a DL TBF establishment in PTM without re-allocation of the on-going UL TBF.


87/267

Alcatel 87



semantic

0

1

The SDU contains signaling (e.g., related to GMM)

The SDU contains data

coding

T bit coding

3.1 Data Transfer EstablishmentDL TBF Establishment, Radio Resource Optimization

MFS

BSSGP PDUn PDCHs

allocated

according to

MS multislotclass

SGSN

(QoS profile, LLC PDU)

Only 1 PDCH allocated

n PDCHs allocated

according to

MS multislot class

8

octet 1

octet 2.2a

octet 3-4

octet 5

IEI

Length Indicator

Peak bit rate provided by the network, coded as

the value part in Bucket Leak Rate/R IE/ GSM 08.18 a)

7 6 5 4 3 2 1

SPARE C/R T A Precedence

QoS Profile IE from BSSGP message GSM 08.18


88/267

Alcatel 88



Time allowed:

30 minutes

3.1 Data Transfer EstablishmentDL TBF Establishment, Exercise

Exercise 1: Identify the type of DL TBFestablishment procedure among the providedtraces 6, 6bis and 8

Exercise 2: identify trace 6bis if the DL TBF isestablished for data or signaling transfer

B9


89/267

Alcatel 89



3.1 Data Transfer EstablishmentDL TBF establishment, failures

DL TBF establishment FAILURE

BSS

Resource

Congestion

Radio pb BSS pb Gb pb

Radio congestion

GPU DSP

congestion

Ater congestion

GPU CPU

congestion

Ab is congestion

Too many TBF

NewB9

NewB9

B9

CPU_LOAD

NewB9


90/267

Alcatel 90



> BSS resource congestion: radio (PDCH, TAI, TFI), Ater, GPU

> Problem at Gb interface level

When the CELL is in the operational state disabled in the BSS

O&M problem

3.1 Data Transfer EstablishmentDL TBF Establishment, Failures, BSS Resource Cong,Gb

MFS

LLC PDUsNo resource available:(radio+Abis+Ater+DSP+CPU)+ CPU_LOAD +too

many TBFsP14+ P105i+

P105g+P105c+P105e+P203+

P105k

SGSN

LLC Discarded

MFS

LLC PDUs

Cell BVC unavailable

P65

SGSN

LLC Discarded

B9

Modified

B9


91/267

Alcatel 91



> Radio problem

> Problem at BSS level

what is not Congestion, Radio, Gb

no specific counter

3.1 Data Transfer EstablishmentDL TBF Establishment, Failures, Radio

MSBTS BSC MFS

Packet control Ack

t_assign_agch_pacch expiry

or t_assign_pch_pacch expiry

or T_ACK_WAIT expiry

or T_ACK_WAIT_DRX_PCCCHexpiry

for the last attempt of the same DL

TBF establishment


PDCHs, TFI, TAI, (EGPRS window size)


PACCH or

b9_24_introduction to gprs and e-gprs qos monitoring 3fl11829abaa

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