Unspecified Call Drop - Test Case 2012

04/11/2023

Sudden Unspecified Call Drop Analysis

In building Site

INDOORGSM & WCDMA COVERAGE TEST

Objective:

To locate and investigate the cause of several sudden dropped calls made by NEMO Handy Smartphone under good Radio Condition in 28th Floor of OPERATOR A House

TEST CASE SCENARIO

Test Cases

26th November 2012

Spot test (static)on each floor:

4 locations on each floor

Round 1: Short Call (Lock 2G)

Round 2: Short Call (Dual Mode)

UE Model

Nemo Handy-HTC Vivid (Smart Phone-Android)

PROBLEM DESCRIPTION: Floor Map (Spot Test)

The above floor plan was used during this walk test procedure and the test was conducted on floor:1- Floor 28

IBC Antenna Location

ROUTE

P1

P2P3

P4CHAM

CHU

RI S

QU

ARE

CU

Rama IV Rd

SPOT TEST RESULTS 3G

IMSI Number: 520189305380760Test Place: 28th Floor

Test Number Test Point Call Attempt Call Success Call Drop Call Block

0816120012

P1 10 9 1 0

P2 10 5 5 0

P3 10 5 5 0

P4 10 5 5 0

181

P1 9 9 0 0

P2 10 9 1 0

P3 10 10 0 0

P4 10 10 0 0

MTM P4 5 5 0 0

Result Analysis – Call Drop 1FLOOR 28 – UMTS – 0816120012

•The signal level at this floor are good. There has no pilot pollution or poor coverage in this point. However, there have a lots of call drop happen during spot test at this floor. • The call drop reason are due to normal, unspecified reason.






•The signal level at this floor are good. There has no pilot pollution or poor coverage in this level. However, there have a lots of call drop happen during spot test at this floor. • The call drop reason are due to switching equipment congestion – indicates that the switching equipment generating this cause is experiencing a period of high traffic.

CALL TRACING ANALYSIS (1/3)

SYSTEM RELEASE NORMAL RELEASE

RNSNK01 MSSRST2-3G

RNSNK01 MSSRST2-3G

RNC 3G MSC RNC 3G MSC

+0.000s ►

+0.000s ►

MM-DMTAP | CM service request MM-DMTAP | CM

service request

+0.019s ◄

+0.009s ◄

SCCP_ITU | Connection Confirm SCCP_ITU |

Connection Confirm

+0.019s

◄

+0.018s

◄

RANAP | initiatingMessage |

id-LocationReportingC

ontrol


id-LocationReportingC

ontrol

+0.033s

◄

+0.018s

◄

RANAP |

initiatingMessage | id-CommonID

RANAP |

initiatingMessage | id-CommonID

+0.033s

◄

+0.018s

◄


id-SecurityModeContr

ol


id-SecurityModeContr

ol

+0.871s

►

+0.140s

►

RANAP | successfulOutcome

| id-SecurityModeContr

ol

RANAP | successfulOutcome

| id-SecurityModeContr

ol

+0.882s ◄

+0.143s ◄

MM-DMTAP | Identity request MM-DMTAP |

Identity request

+0.979s ►

+0.248s ►

CC-DMTAP | Setup CC-DMTAP | Setup

+0.992s ►

+0.260s ►

MM-DMTAP | Identity response MM-DMTAP |

Identity response

The comparisons between SYSTEM to NORMAL RELEASE for the above calls tracing:


+1.002s ◄

+0.264s ◄

CC-DMTAP | Call proceeding CC-DMTAP | Call

proceeding

+1.097s

◄

+0.419s

◄

RANAP |

initiatingMessage | id-RAB-Assignment

RANAP |

initiatingMessage | id-RAB-Assignment

+3.592s ►

+1.000s ►

RANAP | outcome | id-RAB-Assignment RANAP | outcome | id-

RAB-Assignment

+3.599s ◄

+1.548s ◄

CC-DMTAP | Progress CC-DMTAP | Progress

+3.609s ◄

+1.609s ◄

SUPS | Invoke CC-DMTAP | Connect

+3.609s ◄

+1.800s ►

CC-DMTAP | Alerting CC-DMTAP | Connect acknowledge

+3.609s ◄

+120.949s ►

CC-DMTAP | Connect SCCP_ITU | Inactivity Test

+4.159s ►

+124.929s ◄

CC-DMTAP | Connect acknowledge SCCP_ITU | Inactivity

Test

+21.758s

◄

+168.360s

►

CC-DMTAP | Disconnect

| 31 Normal, unspecified

CC-DMTAP | Disconnect

| 16 Normal call clearing

+22.959s

►

+168.366s

◄

CC-DMTAP | Release | 31 Normal, unspecified CC-DMTAP | Release |

16 Normal call clearing

+22.963s

◄

+168.601s

►

CC-DMTAP | Release

complete | 31 Normal, unspecified

CC-DMTAP | Release

complete | 16 Normal call clearing

+22.963s

◄

+168.617s

◄

RANAP | initiatingMessage | id-Iu-Release | 83 normal-

release

RANAP | initiatingMessage | id-Iu-Release | 83 normal-

release

+24.399s

►

+176.709s

►

RANAP |

successfulOutcome | id-Iu-Release

RANAP |

successfulOutcome | id-Iu-Release

+24.450s

◄

+176.759s

◄

RANAP |

initiatingMessage | 3 SCCP user originated

RANAP |

initiatingMessage | 3 SCCP user originated

+24.452s ►

+176.761s ►

SCCP_ITU | Release Complete SCCP_ITU | Release

Complete


RANAP | outcome | id-RAB-Assignment

RANAP | initiating | id-RAB-Assignment

CC-DMTAP | Progress

CC-DMTAP | Connect

CC-DMTAP | Connect acknowledge

SCCP_ITU | Inactivity Test

CC-DMTAP | Disconnect | 16 Normal call clearing

SUPS | Invoke

CC-DMTAP | AlertingCC-DMTAP | Connect

RANAP | outcome | id-RAB-Assignment

RANAP | initiating | id-RAB-Assignment

CC-DMTAP | Progress

1. Through the call tracing analysis it is clearly seen that the call flow for SYSTEM RELEASE – Cause Code 31 Normal Unspecified showed no response from RNSNK01 to MSSRST2-3G MSC leading to the SUPS- INVOKE Signal sent from MSSRST2 to RNSNK01 again

2. The possibility for having routing table on MSSRST2 needs to be further check as the calls were made under very good radio condition

Summary & Recommendation

. 1. The complains of having frequent call drops were initiated from OPERATOR A House at floor 28

2. Further analysis has showed that the radio condition of which the calls were made were GOOD; i.e. RSCP -50’s dBm or better and EcNo -5’s dB

3. Core’s Tracing analysis has demonstrated the abnormal call flow where the RNC did not send the response upon the receipt CC-DMTAP | Progress from MSC

4. Since no response yet from RNC, the MSC sent the Invoke CC DMTAP signal to RNC 5. The call duration was various from 30 seconds up to 2 minutes before DROP occurred6. Further investigation needs to be done on RNSNK01 – MSSRST2 to see some possible

errors of routing table or faults

Documents

Unspecified Call Drop - Test Case 2012