(WCDMA Network MTN South Africa)
1 Introduction 2
2 Dropped Calls Classification 3
2.1 Missing Neighbours 3
2.2 Poor Coverage 4
2.3 Bad Radio Environment 5
2.4 Congestion 6
2.5 Not Radio 7
2.6 Equipment Fault 8
3 Blocked Calls Classification 9
3.1 Missing Neighbour 10
3.2 Poor RF (Bad Coverage and Radio Environment) 11
3.3 Equipment Fault (UE) 12
3.3.1 Security and Authentication Mode Failure 12
3.3.2 UE Freeze 13
3.4 Not Radio 14
3.4.1 Disconnect on RAB Setup 14
3.4.2 Resources Unavailable (Congestion) 15
3.4.3 UE Sensitivity Fault 16
3.5 Abnormal blocked calls 17
3.5.1 Unclassified - Unanswered RRC requests 17
3.5.2 Faulty Block Recording - Barred Network 18
3.5.3 Call Initialisation during L.U. signalling 19
1 Introduction
This document describes some of the typical dropped/blocked call classifications encountered during several RAN Tuning Projects for WCDMA networks. The purpose of the document is for RAN Consultants to understand some of the problems to make the UE analysis and classification easier. The analysis has been based on limited data (for example no UETR data or data based on similar tool, no usage of RBS and RNC tracers) and for this result there could be a deviation in the results. Some of these classifications are only a guideline and should be viewed merely as documenting the typical problem until the correct reason behind the dropped call is established.
All these dropped/blocked calls categories are adapted to the radio environment evaluation thresholds set up for the MTN 3G RAN Tuning project in the post-processing tool TEMS Deskcat 5.6.
In the table below are listed the main causes that must be considered during the analysis, with the explanation for each cause.
CLASSIFICATION CRITERIA
Poor Coverage
The Drop occurs in regions where conditions CPICH RSCP and/or CPICH Ec/No are measured in critical values not suitable for a proper connection.