ctap descritption

MOTOROLA KUWAIT

CALL TRACE ANALYSIS PLATFORM (CTAP)

DONE BY :

ABEER YAKOUB AHMAD ABU SULTAN

MONITOR :

ISHTIYAQ SAWANT

2004

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TABLE OF CONTENTS:

1. INTRODUCTION:------------------------------------------------------------3

2. CALL INITIALIZATION:----------------------------------------------------4

2.1. CALL SETUP CALCULATIONS:-----------------------------------------------4

3. HANDOVER:------------------------------------------------------------------5

3.1. HANDOVER CALCULATIONS:-------------------------------------------------73.1.1 Handover Attempt Rate (HAR):----------------------------------83.1.2 Handover Rejection Rate (HRR):--------------------------------93.1.3 Handover Success Rate (HSR):---------------------------------103.1.4 Handover Failure Rate (HFR):----------------------------------12

4. DROP CALL :---------------------------------------------------------------14

4.1. DROP CALL CALCULATIONS:----------------------------------------------14

5. CTAP FORMS:--------------------------------------------------------------16

5.1. MAIN PAGE FORM:--------------------------------------------------------165.1.1 Components of Main Page Form:------------------------------16

5.2. CALL SETUP CALCULATIONS FORM:--------------------------------------185.2.1 Components of Call Setup Calculations Form:-------------185.2.2 Output Example:---------------------------------------------------21

5.3. HANDOVER CALCULATIONS FORM:---------------------------------------225.3.1 Components of Hanover Calculations Form:---------------225.3.2 Output Examples:--------------------------------------------------24

5.4. DROP CALL CALCULATIONS FORM:---------------------------------------275.4.1 Components of Drop Call Calculations Form:--------------275.4.2 Output Example:---------------------------------------------------28

5.5. Start Using CTAP-------------------------------------------------------29

1. Introduction:Call Trace Analysis Platform (CTAP)

MS (Mobile Station) interchanges several messages with GSM components during its call session, also BSS (Base Station System) has the ability to trace these messages and store it on the OMC (Operation and Maintenance Centre) as log files. Using tool called Trace Call Product (CTP), that has a collection service, call trace files and other configuration data from one or more “OMCs” can be gathered. They can be uploaded on the database at CTP server installation. From here the data is available to one or more connected CTP clients.

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Since each call has its own trace file (some times more than one trace file) that contains all exchanged messages during this call, there will be huge number of these files that are loaded to the CTP daily.From the purpose to analyse the trace files with out wasting time and effort in manual optimisation work, the need to develop such analyzer tool came out. This analyser tool is called Call Trace Analysis Platform (CTAP).“CTAP” is a GUI that is developed using Microsoft Visual basic 6.0, and is built basically on CTP database (SQL database). It is full of SQL statements that are needed to calculate required rates and to pick up necessary details.

CTAP consists of four application forms:1. Main Page Form.2. Call Setup Calculations Form.3. Handover Calculations Form.4. Drop Call Calculations Form.

This document is built with two main parts; the first part discusses all calculations done in CTAP, formulas expression and their descriptions. The second part discusses CTAP forms, their components and output example for each calculation type.

2. Call Initialization:2.1. Call Setup Calculations:

In the Call Setup Success Rate (CSSR) the ratio between the number of X messages and the number of Setup Mobile Station to Network messages is calculated as shown in the following formula:

No. X messages CSSR =

No. Setup Mobile Station to Network messages

Provided: Setup Mobile Station to Network messages

Exist In the same Trace File should be counted as one message.

The X message can been one of the following messages: Assignment Request Assignment Command Call Proceeding Alerting

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3. Handover:Whenever a mobile is operating on a voice channel, the base station and the MS monitors the received signal level. When the level of neighbor cell becomes greater than the service cell by specific value for specific period the base station informs its MSC (or BSC) that handover to a nearby cell may be necessary. The MSC (or BSC) then co-ordinates with the associated neighbor to perform the handover

In this process, the relevant base station is requested to allocate a voice channel and the MSC informs the mobile that it must tune to a new channel. A short message is sent to the mobile giving the new channel number and the mobile will tune to the new channel. The duration of the signaling message is about 400 ms, and so the user may notice a short silence during the handover.

There are three possible types of handover in the GSM system.

1. Intra - cell handover - This occurs between channels within the same cell.

2. Intra – BSC handover – This occurs between channels in different cells under the control of the same Base Station Controller (BSC).

3. Inter – BSC Handover – This occurs between cells under the control of different BSCs, but belonging to the same Mobile services Switching Center (MSC),

4. Inter - MSC handover – This occurs between cells belonging to different MSC's.

The first two types of handover, called internal handovers, involve only one Base Station Controller (BSC). To save signaling bandwidth, they are managed by the BSC without involving the Mobile service Switching Center (MSC), except to notify it at the completion of the handover. The last two types of handover, called external handovers, are handled by the MSCs. Handovers can be initiated by either the mobile or the MSC during its idle time slots, the mobile scans the Broadcast Control Channel of up to 16 neighboring cells, and forms a list of the six best candidates for possible handover, based on the received signal strength. This information is passed to the BSC and MSC, and is used by the handover algorithm.

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As mentioned before, in order to perform such process, a lot of messages should be exchanged between the MS and the GSM Components. Related to the Handover operation many types of messages will be created. In this tool the following messages are used in the Handover calculations

HANDOVER RECOGNISED. Hanover Command. Hanover Performed. Clear Command. Hanover Failure. Hanover Required Reject.

3.1.Handover Calculations:As we discussed before external handover is controlled by the MSC and it has two different types one is Inter BSC Handover and Inter MSC Handover. Fig 3.1 describes the external handover process and its calculations.

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Fig 3.1 External Handover Process

External handover process will start when source recognizes that a handover is needed, so HANDOVER RECOGNISED message will be sent to the MSC which either will send Handover Acknowledge or Handover required reject or no response will come to the source. Once the source receives Handover Acknowledge, Handover Command including information needed to perform handover process will be sent to the MS. And finally handover may or may not succeed. As shown in Fig 3.1 four types of handover calculations can be calculated here:

1. Handover Attempt Rate (HAR).2. Handover Rejection Rate (HRR).3. Handover Success Rate (HSR).4. Handover Failure Rate (HFR).

The following sections discuss separately each one of these types.

3.1.1Handover Attempt Rate (HAR):

HANDOVER RECOGNISED

Handover Acknowledge

Handover Required Reject Handover Command

Handover Success Handover Failure

1

2

3 4

No ResponseHandover Attempt Rate

Handover Rejection Rate

Handover Success Rate Handover Failure Rate

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In this type of Handover Success Rate the ratio between the number of Handover Command messages and the number of HANDOVER RECOGNISED messages is calculated as shown in the following formula:

No. Handover Command messages HAR =

No. HANDOVER RECOGNISED messages

Provided: Handover Command messages with the same Handover References In the same Trace File are calculated as one message.

Since HANDOVER RECOGNISED and Handover Command messages exist in Intra BSC Handover, Handover Attempt Rate (HAR) indicates the performance level in external handovers (Inter BSC Handover and Inter MSC Handover) as well as Intra BSC Handover.

3.1.2 Handover Rejection Rate (HRR):In this type of handover failure rate the ratio between number of Handover required reject messages and number of HANDOVER RECOGNISED messages is calculated as shown in the following formula:

No. Handover required reject HRR =

No. HANDOVER RECOGNISED messages

Handover Rejection Rate (HRR) indicates the performance level in external handovers (Inter BSC Handover and Inter MSC Handover) only. But since HANDOVER RECOGNISED is used in Intra BSC Handover while Handover required reject is not, this may cause HRR to get bigger value than expected. So here HRR will act as alarm that indicates performance level of external handover approximately.

The Trace Files Details (Sccp, Cell id, Start Date) where Handover required reject is faced will be displayed that optimizers can check them easily.

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3.1.3 Handover Success Rate (HSR):In this type of Handover Success Rate the ratio between the number of Handover Success Messages (Handover Performed and Clear Command) and the number of Handover Command messages is calculated as shown in the following formula:

No. Clear Command + No. Handover Performed HSR =

No. Handover Command messages

Provided: Clear Command message will be considered in

this formula only if it has Handover Successful (11) as a cause.

Handover Performed message will be considered in this formula only if it has Better Cell (12) as a cause.

Handover Command messages with the same Handover References in the same trace file are calculated as one message.

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In Table 3.1 and Table 3.2, some of the causes that may be included in Clear Command messages and Handover performed messages.

As shown in Table 3.1 Clear Command has many causes, but the only cause that related to handover process is cause number 11 with description of Handover Successful. That is why HSR formula includes Clear Command only if it has cause 11.

Table 3.1 Clear Command Causes

Table 3.2 Handover Performed Causes

Cause Number

Cause Description

2 Uplink Quality4 Downlink Quality7 O and M Intervention12 Better Cell15 Traffic

Cause Number

Cause Description

0 Radio Interface Message Failure

1 Radio Interface Failure9 Call Control11 Handover Successful32 Equipment Failure33 No Radio Resource Available

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3.1.4

Handover Failure Rate (HFR):In this type of handover failure rate the ratio between the number of Handover Failure Messages (Hanover Failure and Hanover failure) and the number of Handover Command messages is calculated as shown in the following formula:

No. Handover Failure HFR =

No. Handover Command messages

Provided: Handover Command messages with the same

Handover References in the same trace file are calculated as one message.

Since Handover Command and Handover Failure messages exist in Intra BSC Handover, Handover Failure Rate (HFR) indicates the performance level in external handovers (Inter BSC Handover and Inter MSC Handover) as well as Intra BSC Handover.

The Trace Files Details (Sccp, Cell id, Start Date) where Handover Failure exist will be displayed, also Handover Failure message causes and percentage of each cause will be displayed. Table 3.3 lists some of these causes.

RR Cause Number

Cause Description

0 Normal Event

1 Abnormal release, unspecified

3 Abnormal release, time expired

8 Handover impossible, timing advance out of range

111 Protocol error, unspecified

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Table 3.3 Handover Failure RR Causes.

4. Drop Call :Most of us faced some of dropping during their calls, what is the rate of these dropped Calls? What are the different causes of dropping? What other details related to dropped calls? Drop Call Calculations Form should answers these questions.

4.1.Drop Call Calculations: Drop Call Rate (DCR) will be calculated according the following

formula:

No. Clear Request messages DCR =

No. Assignment Command messages

Provided: Clear Request with cause Call Control (9) or Handover Successful (11) should not be counted. Assignment Commands exist in the same

Trace File should be counted as one message.

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As shown in Tables 3.1, Clear Request message may come with cause 9 (Call control) or cause 11 (Handover Successful) and since Clear Request messages in this cause are not related to drop call process it should be included in the calculations of DCR.

In the Drop Call Rate, number of Assignment Command messages should refer to the number of Trace Files that succeed in the setup operation and have already received Assignment Command. So that is why Assignment Commands exist in the same Trace File should be counted as one message.

Related to the DCR the following information will be displayed: Drop Causes and Their

Percentage. Details of Trace Files that are

related to each drop cause.

There is another type of calculations that will be displayed for the user in the Drop Call calculations form, which is called Down Link Disconnect Percentage. We said that down link disconnect happened when the GSM network disconnects calls rather than the MS itself.

No. Disconnect messagesDLD (%) =

No. Assignment Command messages

Provided: Disconnect message should have ‘Network

to MS’ as a type.

In this formula that calculates the Down Link Disconnect Percentage, Disconnect message will be included only if it has Network to MS as its type, because this is actually what Down Link Disconnect means.

The Trace Files Details will be displayed for calls that faced Down Link Disconnect.

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5. CTAP Forms:5.1.Main Page Form:

Fig 5.1 Main Page Form

5.1.1Components of Main Page Form:1. Menu

CTAPo Exit : To Exit CTAP

Databaseo Load : To load the database into CTAP formso Refresh: To reload the database into CTAP forms. If

during using CTAP new Trace Files are loaded in to database, user should refresh the loaded information.

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2. Three Buttons Call Setup Calculation Button. Handover Calculations Button. Drop Call Calculations Button.

3. Status Bar CTAP status bar has four panels,

Panel 1: To display the state of the form Panel 2: To display if the database is loaded to

CTAP or not, and if the database is loaded the number of trace files will be displayed.

Panel 3: Contains the progress bar that works during the database loading process.

Panel 4: Contains the string Motorola Kuwait.

5.2.Call Setup Calculations Form:Call Success Rate Form is one of the main forms in CTAP; it is used to calculate the Call Success Rate (CSSR) for specific calls. Fields selected by the user specify these calls.

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Fig 5.2 Call Setup Calculations Form

5.2.1Components of Call Setup Calculations Form:1. Menu

Databaseo Refresh: To reload the database into CTAP forms. If

during using CTAP new Trace Files are loaded in to database, user should refresh the loaded information.

2. The Type of Message for which the CSSR will be calculatedAs mentioned the user can either select Assignment

RequestAssignment Command, Call Proceeding or Alerting.

3. The Date Range Combos: The user specifies the start date and the end date for the range to calculations should be done.If the user forgets to specify one of the two dates, error message will be displayed (Fig 5.3). And if the end date in older than the start date (Not logical) another error message will be displayed (Fig 5.4).

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Fig 5.3 Not Specified Date Error Message

Fig 5.4 Wrong Date Range Error Message

4. The Cell Id Combo:The user can specify Cell Id for which he is interest to find the calculations related to it.

5. The Dialed Number Combo:Also the user can specify a Dialed Number.

6. Calculate CSSR Button

7. The Output Window Textbox:In this Window the user specification and all results will be displayed once Calculate CSSR Button is clicked.

8. Forms Combo:From this Combo the user can select the form for which he wants to move.

9. Status Bar CTAP status bar has four panels,

Panel 1: To display the state of the form Panel 2: To display if the database is loaded to

CTAP or not, and if the database is loaded the number of trace files will be displayed.

Panel 3: Contains the progress bar that works during the database loading process.

Panel 4: Contains the string Motorola Kuwait.

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5.2.2Output Example:

5.3.Handover Calculations Form: The Second form in CTAP is related to Hanover calculations, same as Call Success Rate Form all calculations are done according to user specification.

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Your Specification:--------------Call Setup Success Rate:Alerting Messages to 'Setup mobile station to network' Messages

Date ---> Between 23/05/2004 AND 15/06/2004Cell Id ---> Not SpecifiedDialed Number ---> Not Specified

Results:--------------CSSR = 93.2476 % Calculated for 311 Calls

Trace Files Details For Calls That Failed in Alerting Message *********************************** Sccp Start Date

336896 30/05/2004 1933056 02/06/2004 2439680 06/06/2004 870048 07/06/2004 344416 08/06/2004 2508096 08/06/2004 17952 08/06/2004 1457824 08/06/2004 1714944 08/06/2004 2453408 15/06/2004 2715296 15/06/2004 1724512 15/06/2004 1719616 15/06/2004 883840 15/06/2004 552448 15/06/2004 2311424 15/06/2004 1864704 15/06/2004 1863360 15/06/2004 1856576 15/06/2004 1853248 15/06/2004 3096256 15/06/2004

Number of Trace Files with distinct trace file id where Setup mobile station to network Message exits.

Fig 5.5 Handover Calculations Form

5.3.1Components of Hanover Calculations Form:1. Menu Database

o Refresh: To reload the database into CTAP forms. If during using CTAP new Trace Files are loaded in to database, user should refresh the loaded information.

2. Type Of Hanover Calculations Frame : Handover Success calculations Option button. Hanover Fail calculations Option button.

3. Type Of Hanover Success Calculations Frame : Handover Attempt Rate (HAR) Option button. Handover Success rate (HSR) Option button.

4. Type Of Hanover Failure Calculations : Handover Failure Rate (HFR) Option button. Handover Rejection Rate (HRR) Option button.

Once this form in loading the first and the second frame is enabled and the third form is disabled, then according to the user selection in the first frame, one of the two remaining frames will be enabled.

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5. The Date Range Combos6. The Cell Id Combo7. The Dialed Number Combo 8. Calculate Handover Rate Button9. The Output Window Textbox10. Forms Combo11. Status Bar

Components from 5 – 11 have the same features that exist in the Call Setup Calculations Form.

5.3.2Output Examples:

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Your Specification:--------------Handover Attempt Rate(HAR):Handover Command Messages to HANDOVER RECOGNISED Messages


Results:--------------HAR = 90.0358% for 1249 Trace File Records

Your Specification:--------------Handover Success Rate(HSR):Handover Success Messages To Handover Command Messages


Results:--------------HSR = 26.8090% for 1174 Trace File Records

Number of Trace Files with distinct trace file id where HANDOVER RECOGNISED Message exits.

Number of Trace Files with distinct trace file id where Handover Command Message exits.

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Your Specification:--------------Handover Failure Rate(HFR):Handover Failure Messages To Handover Command Messages


Results:--------------

HFR = 01.1960% for 523 Trace File Records

Handover Failure Causes And Their Description ************************************ Protocol error, unspecified. = 53.8462% Abnormal release, unspecified = 07.6923% Abnormal release, timer expired = 15.3846% Handover impossible, timing advance out of range = 23.0769%

Trace Files Details For Calls That Failed in Handover Process *********************************** Sccp Start Date

397216 01/05/2004 410017 01/05/2004 1735168 01/05/2004 2051776 01/05/2004 2451872 01/05/2004 2952736 01/05/2004 2969632 01/05/2004 3043232 01/05/2004 3098144 01/05/2004

Your Specification:--------------Handover Rejection Rate(HRR):Handover required reject Messages to HANDOVER RECOGNISED Messages


Results:--------------

HRR = 00.9118% for 1249 Trace File Records

Trace Files Details For Calls That Failed in Handover required reject Message *********************************** Sccp Start Date

2317344 01/05/2004 2309952 01/05/2004 1576256 01/05/2004 1986592 01/05/2004 1901376 01/05/2004 1796448 15/06/2004 1716320 15/06/2004 2645696 15/06/2004 3168608 16/06/2004 2441632 15/07/2004 2701952 15/07/2004

Number of Trace Files with distinct trace file id where Handover Command Message exits.

Number of Trace Files with distinct trace file id where HANDOVER RECOGNISED Message exits.

5.4.Drop Call Calculations Form:

Fig 5.6 Drop Call Calculations Form

5.4.1Components of Drop Call Calculations Form:1. Menu2. The Date Range Combos

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3. The Cell Id Combo4. The Dialed Number Combo5. Calculate Drop Call rate Button 6. The Output Window Textbox7. Forms Combo8. Status Bar

5.4.2Output Example:

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Your Specification:--------------Drop Call Rate (DCR): Clear Request Messages To Assignment Command Messages


Results:--------------

DCR(3) = 00.5199% Calculated for 577 Calls * Value between brackets is the number of dropped calls

Down Link Disconnect(DLD)% = 57.5390% Calculated for 577 Calls

Drop Causes And Their Percentage *********************************** Equipment failure = 33.3333% Radio interface message failure = 66.6667%

Trace Files Details For Equipment failure dropped Calls *********************************** Sccp Start Date

1929824 01/05/2004

Trace Files Details For Radio interface message failure dropped Calls *********************************** Sccp Start Date

2304768 01/05/2004 3168256 01/05/2004

Trace Files Details For Down Link disconnected Calls *********************************** Sccp Start Date

5056 01/05/2004 5120 01/05/2004 11296 01/05/2004

Number of Trace Files with distinct trace file id where Assignment Command Message exits.

5.5.Start Using CTAPAs mentioned before that CTAP is built on the CTP database, CTP database exits in the data source (ODBC) with MQIS name and SQL Server driver. CTAP is link directly with this database, so before starting using CTAP, the MQIS database should exits in the ODBC.

First steps that should be taken to start using CTAP: 1)

Fig 5.7 Step1

2)

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Fig 5.8 Step2

3)

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Fig 5.9 Step 3

4)

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Fig 5.10 Step 4After this step all the three buttons are enabled and the user can start finding the needed calculations.

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ctap descritption

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