Product NameConfidentiality Level G3BSC Confidential Product Version Total 24 pages Baseline Specifications for GSM BSS Network Performance KPIs (Call Drop Ratio on TCH) For internal use only Wu Zhen, WCDMA & GSM Performance Research Dept. Prepared by: Date: 2007-05-26 Reviewed by: Date: yyyy-mm-dd Reviewed by: Date: yyyy-mm-dd Approved by: Date: yyyy-mm-dd Huawei Technologies Co., Ltd. All rights reserved Table of Contents 1 About KPI Definition..................................................................................................................... 1.1 KPI Name............................................................................................................................. 1.2 KPI Meaning......................................................................................................................... 1.3 Recommended Formula....................................................................................................... 1.3.1 Formula of the BSC32............................................................................................... 1.3.2 Formula of the BSC6000........................................................................................... 1.3.3 Measurement Time Points.......................................................................................13 1.4 Other Definition Modes of the KPI......................................................................................16 1.4.1 KPI Definition of Ericsson........................................................................................ 16 1.4.2 KPI Definition of Nokia............................................................................................. 17 1.4.3 KPI Definition of Siemens........................................................................................ 18 1.4.4 KPI Definition of Motorola........................................................................................ 19 1.5 Suggestions on KPI Optimization.......................................................................................21 2 KPI Test Method.......................................................................................................................... 22 3 KPI Baseline................................................................................................................................ 22 3.1 Baseline of Call Drop Ratio on TCH of the BSC32.............................................................22 3.2 Baseline of Call Drop Ratio on TCH of the BSC6000.........................................................23 4 Constraint Analysis.................................................................................................................... 23 4.1 Test Method Constraints..................................................................................................... 23 4.2 Test Environment Constraints............................................................................................ 23 4.3 KPI Definition Constraints.................................................................................................. 24 4.4 Parameter Constraints....................................................................................................... 24 4.5 Function Constraints.......................................................................................................... 26 4.6 Inter-KPI Constraints.......................................................................................................... 27 4.7 Version Constraints............................................................................................................ 27 5 Baseline Commitments.............................................................................................................. 28 5.1 Baseline Commitments...................................................................................................... 28 5.1.1 Baseline Commitments in the Event of Network Relocation....................................28 5.1.2 Baseline Commitments in the Event of New Network Construction.........................29 5.1.3 Risk Analysis............................................................................................................ 29 6 KPI Optimization Means............................................................................................................. 29 .................................................................List of Figures Figure 1 Channel seizure in the immediate assignment procedure..14 .........................................................13 Figure 3 Channel seizure in the internal handover procedure of the BSC..........14 Figure 4 Channel seizure in the incoming BSC handover procedure..................13 Figure 2 Channel seizure in the assignment procedure............ Wu Zhen 2007-6-16 V1.0 Completed the initial draft.Revision History Date Revision Version Change Description Author 2007-5-26 V1. Wu Zhen .1 Modified the document according to the review comments. test method and constraints of the call drop ratio on TCH. Acronyms and Abbreviations Abbreviation Full Spelling . KPI Abstract This document describes the definition.Baseline Specifications for GSM BSS Network Performance KPIs (Call Drop Ratio on TCH) Keywords Call drop ratio on TCH. 2 Formula of the BSC6000 Call Drop Ratio on TCH (Including Handover) = (Call Drops due to ERR IND Received on TCHF (TCH) in Stable State (T200 Expired) + Call Drops due to ERR IND Received on TCHF (TCH) in Stable State (Unsolicited DM Response) + Call Drops due to ERR IND Received on TCHF (TCH) in Stable State (Sequence Error) + Call Drops due to ERR IND Received on TCHH (TCH) in Stable State (T200 Expired) + Call Drops due to ERR IND Received on TCHH (TCH) in Stable State (Unsolicited DM Response) +Call Drops due to ERR IND Received on TCHH (TCH) in . The following formula is recommended for it: Call drops on TCH / Successful TCH seizures. 1. The “current version” described hereinafter refers to the following: BSC32: G3BSC32V300R007C01 BSC6000: BSC6000V900R001 1.3 Recommended Formula The call drop ratio on TCH is mostly obtained through the traffic measurement results or through the drive test. One is to assess the probability of call drops on all established TCHs in the cell and the other is to assess the probability of call drops on TCHs during call establishment of the cell.1 Formula of the BSC32 Call Drop Ratio on TCH (including handover) = (Call Drops on TCH + Call Drops on TCH in Very Early Assignment) / Successful TCH Seizures (All) × 100% Call Drop Ratio on TCH (excluding handover) = Call Drops on TCH / (Successful TCH Seizures + Successful Incoming Internal Inter-Cell Handovers + Successful Incoming External Inter-Cell Handovers .Successful Outgoing Internal Inter-Cell Handovers . It indicates the probability of failure to normally end the conversation due to various reasons after the MS normally accesses the TCH. The call drop ratio on TCH is an important index of the call hold type. It can be assessed from two aspects. Because the BSC32 and the BSC6000 have difference only in the index names used in the specific calculation formula and do not have any difference in the measurement time points.1 About KPI Definition The KPI is determined by the name.Successful Outgoing External Inter-Cell Handovers) × 100% 1.3“Recommended Formula” gives the calculation formulas of the BSC32 and the BSC6000.3.2 KPI Meaning The call drop ratio on TCH reflects the ratio of call drops to successful TCH seizures after the BSC successfully assigns a TCH to the MS.3. A too high call drop ratio on TCH will directly influence subscribers’ feeling. section 1. meaning and definition. 1. The other contents are the same for both.1 KPI Name Call drop ratio on TCH 1. Channel Type Unchangeable) + Assignment Requests (TCHF or TCHH. Channel Type Unchangeable) + Assignment Requests (TCHH Preferred. Channel Type Changeable) + Assignment Requests (TCHF or TCHH. Channel Type Changeable) + Assignment Requests (TCHH Preferred. Channel Type Unchangeable) + Assignment Requests (TCHF Preferred.Stable State (Sequence Error) +Call Drops due to ERR IND Received on TCHF (TCH) in Stable State (Radio Link Failure) + Call Drops due to ERR IND Received on TCHF (TCH) in Stable State (HO Access Failure) + Call Drops due to ERR IND Received on TCHF (TCH) in Stable State (OM Intervention) + Call Drops due to ERR IND Received on TCHF (TCH) in Stable State (Radio Resource Unavailable) + Call Drops due to ERR IND Received on TCHF (TCH) in Stable State (Other Causes) + Call Drops due to ERR IND Received on TCHH (TCH) in Stable State (Radio Link Failure) + Call Drops due to ERR IND Received on TCHH (TCH) in Stable State (HO Access Failure) + Call Drops due to ERR IND Received on TCHH (TCH) in Stable State (OM Intervention) + Call Drops due to ERR IND Received on TCHH (TCH) in Stable State (Radio Resource Unavailable) + Call Drops due to ERR IND Received on TCHH (TCH) in Stable State (Other Causes) + Call Drops due to REL IND Received on TCHF (TCH) + Call Drops due to REL IND Received on TCHH (TCH) + Call Drops due to Abis Terrestrial Link Failure (TCHF) (TCH) + Call Drops due to Abis Terrestrial Link Failure (TCHH) (TCH) + Failed Internal Intra-Cell Handovers (Timer Expired) (TCHF) (Traffic Channel) + Failed Internal Intra-Cell Handovers (Timer Expired) (TCHH) (Traffic Channel) + Failed Outgoing Internal Inter-Cell Handovers (Timer Expired) (TCHF) (Traffic Channel) + Failed Outgoing Internal Inter-Cell Handovers (Timer Expired) (TCHH) (Traffic Channel) + Failed Outgoing External Inter-Cell Handovers (T8 Expired) (TCHF) (Traffic Channel) + Failed Outgoing External Inter-Cell Handovers (T8 Expired) (TCHH) (Traffic Channel) + Call Drops due to No MRs from MS for a Long Time (TCHF) (TCH) + Call Drops due to No MRs from MS for a Long Time (TCHH) (TCH) + Call Drops due to Equipment Failure (TCHF) (TCH) + Call Drops due to Equipment Failure (TCHH) (TCH) + Call Drops due to Forced Handover (TCHF) (TCH) + Call Drops due to Forced Handover (TCHH) (TCH)) / (Channel Activation Attempts in Immediate Assignment Procedure (TCHF) + Channel Activation Attempts in Immediate Assignment Procedure (TCHH)) – (CHAN ACTIV NACK Messages Sent by BTS in Immediate Assignment Procedure (TCHF) + CHAN ACTIV NACK Messages Sent by BTS in Immediate Assignment Procedure (TCHH) + Channel Activation Timeouts in Immediate Assignment Procedure (TCHF) + Channel Activation Timeouts in Immediate Assignment Procedure (TCHH)) + (Assignment Requests (Signaling Channel) + Assignment Requests (TCHF Only) + Assignment Requests (TCHH Only) + Assignment Requests (TCHF Preferred. Channel Type Changeable)) (Failed Assignments during MOC on the A Interface (Including Directed Retry) + Failed Assignments during MTC on the A Interface (Including Directed Retry) + Failed Assignments during Emergency Call on the A Interface (Including Directed Retry) + Failed Assignments during Call Re-establishment on the A Interface (Including Directed Retry) + Failed Mode Modify Attempts (MOC) (TCHF) + Failed Mode Modify Attempts (MTC) (TCHF) + Failed Mode Modify Attempts (Emergency Call) (TCHF) + Failed Mode Modify Attempts (Call Re-establishment) (TCHF) + Failed Mode Modify Attempts (MOC) (TCHH) + Failed Mode Modify Attempts (MTC) (TCHH) + Failed Mode Modify Attempts (Call Re-establishment) (TCHH) + Failed Assignments (Signaling Channel)) + (Internal Intra-Cell Handover Detection Messages Received by BSC (TCHF) + Internal Intra-Cell Handover Detection Messages Received by BSC (TCHH) + Incoming Internal Inter-Cell Handover Detection Messages Received by BSC (TCHF) + Incoming Internal Inter-Cell Handover Detection Messages Received by BSC (TCHH) + Incoming External InterCell Handover Detection Messages Received by BSC (TCHF) + Incoming External Inter-Cell Handover Detection Messages Received by BSC (TCHH))) × 100% Call Drop Ratio on TCH (Excluding Handover) = (Call Drops due to ERR IND Received on TCHF (TCH) in Stable State (T200 Expired) + Call Drops due to ERR IND Received on TCHF (TCH) in Stable State (Unsolicited DM Response) + Call Drops due to ERR IND Received on TCHF (TCH) in Stable State (Sequence Error) + Call Drops due to ERR IND Received on TCHH (TCH) in Stable State (T200 Expired) + Call Drops due to ERR IND Received on TCHH (TCH) in Stable State (Unsolicited DM Response) +Call Drops due to ERR IND Received on TCHH (TCH) in Stable State (Sequence Error) +Call Drops due to ERR IND Received on TCHF (TCH) in Stable . Channel Type Unchangeable) + Assignment Requests (TCHF or TCHH.Failed Incoming Internal Inter-Cell Handovers (TCH) (1800/1900-1800/1900) . Channel Type Unchangeable) + Assignment Requests (TCHF Preferred. Channel Type Changeable) + Assignment Requests (TCHH Preferred.Failed Incoming Internal InterCell Handovers (SDCCH) (900/850-1800/1900) .Failed Incoming Internal Inter-Cell Handovers (SDCCH) (1800/1900-900/850) .Failed Incoming Internal Inter-Cell Handovers (TCH) (900/850-1800/1900) .Failed Incoming Internal Inter-Cell Handovers (SDCCH) (1800/1900-1800/1900) .State (Radio Link Failure) + Call Drops due to ERR IND Received on TCHF (TCH) in Stable State (HO Access Failure) + Call Drops due to ERR IND Received on TCHF (TCH) in Stable State (OM Intervention) + Call Drops due to ERR IND Received on TCHF (TCH) in Stable State (Radio Resource Unavailable) + Call Drops due to ERR IND Received on TCHF (TCH) in Stable State (Other Causes) + Call Drops due to ERR IND Received on TCHH (TCH) in Stable State (Radio Link Failure) + Call Drops due to ERR IND Received on TCHH (TCH) in Stable State (HO Access Failure) + Call Drops due to ERR IND Received on TCHH (TCH) in Stable State (OM Intervention) + Call Drops due to ERR IND Received on TCHH (TCH) in Stable State (Radio Resource Unavailable) + Call Drops due to ERR IND Received on TCHH (TCH) in Stable State (Other Causes) + Call Drops due to REL IND Received on TCHF (TCH) + Call Drops due to REL IND Received on TCHH (TCH) + Call Drops due to Abis Terrestrial Link Failure (TCHF) (TCH) + Call Drops due to Abis Terrestrial Link Failure (TCHH) (TCH) + Failed Internal Intra-Cell Handovers (Timer Expired) (TCHF) (Traffic Channel) + Failed Internal Intra-Cell Handovers (Timer Expired) (TCHH) (Traffic Channel) + Failed Outgoing Internal Inter-Cell Handovers (Timer Expired) (TCHF) (Traffic Channel) + Failed Outgoing Internal Inter-Cell Handovers (Timer Expired) (TCHH) (Traffic Channel) + Failed Outgoing External Inter-Cell Handovers (T8 Expired) (TCHF) (Traffic Channel) + Failed Outgoing External Inter-Cell Handovers (T8 Expired) (TCHH) (Traffic Channel) + Failed Incoming External Inter-Cell Handovers (Timer Expired) (TCH) (Traffic Channel) + Call Drops due to No MRs from MS for a Long Time (TCHF) (TCH) + Call Drops due to No MRs from MS for a Long Time (TCHH) (TCH) + Call Drops due to Equipment Failure (TCHF) (TCH) + Call Drops due to Equipment Failure (TCHH) (TCH) + Call Drops due to Forced Handover (TCHF) (TCH) + Call Drops due to Forced Handover (TCHH) (TCH)) / ( (Assignment Requests (Signaling Channel) + Assignment Requests (TCHF Only) + Assignment Requests (TCHH Only) + Assignment Requests (TCHF Preferred. Channel Type Changeable)) .(Failed Assignments during MOC on the A Interface (Including Directed Retry) + Failed Assignments during MTC on the A Interface (Including Directed Retry) + Failed Assignments during Emergency Call on the A Interface (Including Directed Retry) + Failed Assignments during Call Reestablishment on the A Interface (Including Directed Retry) + Failed Mode Modify Attempts (MOC) (TCHF) + Failed Mode Modify Attempts (MTC) (TCHF) + Failed Mode Modify Attempts (Emergency Call) (TCHF) + Failed Mode Modify Attempts (Call Re-establishment) (TCHF) + Failed Mode Modify Attempts (MOC) (TCHH) + Failed Mode Modify Attempts (MTC) (TCHH) +Failed Mode Modify Attempts (Call Re-establishment) (TCHH) + Failed Assignments (Signaling Channel) + (Incoming Internal Inter-Cell Handover Requests (SDCCH) (900/850-900/850) + Incoming Internal Inter-Cell Handover Requests (SDCCH) (1800/1900-1800/1900) + Incoming Internal Inter-Cell Handover Requests (SDCCH) (900/850-1800/1900) + Incoming Internal InterCell Handover Requests (SDCCH) (1800/1900-900/850) + Incoming Internal Inter-Cell Handover Requests (TCH) (900/850-900/850) + Incoming Internal Inter-Cell Handover Requests (TCH) (1800/1900-1800/1900) + Incoming Internal Inter-Cell Handover Requests (TCH) (900/8501800/1900) + Incoming Internal Inter-Cell Handover Requests (TCH) (1800/1900-900/850) Failed Incoming Internal Inter-Cell Handovers (SDCCH) (900/850-900/850) . Channel Type Changeable) + Assignment Requests (TCHF or TCHH.Failed Incoming Internal Inter-Cell Handovers (TCH) (900/850900/850) .Failed Incoming Internal Inter-Cell Handovers (TCH) (1800/1900-900/850)) + (Incoming External Inter-Cell Handover Requests (SDCCH) (900/850-900/850) + Incoming External Inter-Cell Handover Requests (SDCCH) (1800/1900-1800/1900) + Incoming External Inter-Cell Handover Requests (SDCCH) (900/850-1800/1900) + Incoming External Inter-Cell Handover Requests (SDCCH) (1800/1900900/850) + Incoming External Inter-Cell Handover Requests (TCH) (900/850-900/850) + Incoming External Inter-Cell Handover Requests (TCH) (1800/1900-1800/1900) + Incoming External Inter-Cell Handover Requests (TCH) (900/850-1800/1900) + Incoming External Inter- . Channel Type Unchangeable) + Assignment Requests (TCHH Preferred. Cell Handover Requests (TCH) (1800/1900-900/850)) .(Failed Outgoing Internal Inter-Cell Handovers (SDCCH) (Excluding Directed Retry) (900/850-900/850) + Failed Outgoing Internal Inter-Cell Handovers (SDCCH) (Excluding Directed Retry) (1800/19001800/1900) + Failed Outgoing Internal Inter-Cell Handovers (SDCCH) (Excluding Directed Retry) (900/850-1800/1900) + Failed Outgoing Internal Inter-Cell Handovers (SDCCH) (Excluding Directed Retry) (1800/1900-900/850) + Failed Outgoing Internal Inter-Cell Handovers (TCHF) (Excluding Directed Retry) (900/850-900/850) + Failed Outgoing Internal Inter-Cell Handovers (TCHF) (Excluding Directed Retry) (1800/1900-1800/1900) + Failed Outgoing Internal Inter-Cell Handovers (TCHF) (Excluding Directed Retry) (900/850-1800/1900) + Failed Outgoing Internal Inter-Cell Handovers (TCHF) (Excluding Directed Retry) (1800/1900-900/850) + Failed Outgoing Internal Inter-Cell Handovers (TCHH) (Excluding Directed Retry) (900/850-900/850) + Failed Outgoing Internal Inter-Cell Handovers (TCHH) (Excluding Directed Retry) (1800/19001800/1900) + Failed Outgoing Internal Inter-Cell Handovers (TCHH) (Excluding Directed Retry) (900/850-1800/1900) + Failed Outgoing Internal Inter-Cell Handovers (TCHH) (Excluding Directed Retry) (1800/1900-900/850) + Failed Outgoing Internal Inter-Cell Handovers (Directed Retry) (900/850-900/850) + Failed Outgoing Internal Inter-Cell Handovers (Directed Retry) (1800/1900-1800/1900) + Failed Outgoing Internal Inter-Cell Handovers (Directed Retry) (900/850-1800/1900) + Failed Outgoing Internal Inter-Cell Handovers (Directed Retry) (1800/1900-900/850)).(Failed Incoming External Inter-Cell Handovers (SDCCH) (900/850-900/850) + Failed Incoming External Inter-Cell Handovers (SDCCH) (1800/1900-1800/1900) + Failed Incoming External Inter-Cell Handovers (SDCCH) (900/850-1800/1900) + Failed Incoming External Inter-Cell Handovers (SDCCH) (1800/1900900/850) + Failed Incoming External Inter-Cell Handovers (TCH) (900/850-900/850) + Failed Incoming External Inter-Cell Handovers (TCH) (1800/1900-1800/1900) + Failed Incoming External Inter-Cell Handovers (TCH) (900/850-1800/1900) + Failed Incoming External Inter-Cell Handovers (TCH) (1800/1900-900/850)) – (Outgoing Internal Inter-Cell Handover Requests (SDCCH) (Excluding Directed Retry) (900/850-900/850) + Outgoing Internal Inter-Cell Handover Requests (SDCCH) (Excluding Directed Retry) (1800/1900-1800/1900) + Outgoing Internal InterCell Handover Requests (SDCCH) (Excluding Directed Retry) (900/850-1800/1900) + Outgoing Internal Inter-Cell Handover Requests (SDCCH) (Excluding Directed Retry) (1800/1900-900/850) + Outgoing Internal Inter-Cell Handover Requests (TCHF) (Excluding Directed Retry) (900/850900/850) + Outgoing Internal Inter-Cell Handover Requests (TCHF) (Excluding Directed Retry) (1800/1900-1800/1900) + Outgoing Internal Inter-Cell Handover Requests (TCHF) (Excluding Directed Retry) (900/850-1800/1900) + Outgoing Internal Inter-Cell Handover Requests (TCHF) (Excluding Directed Retry) (1800/1900-900/850) + Outgoing Internal Inter-Cell Handover Requests (TCHH) (Excluding Directed Retry) (900/850-900/850) + Outgoing Internal Inter-Cell Handover Requests (TCHH) (Excluding Directed Retry) (1800/1900-1800/1900) + Outgoing Internal Inter-Cell Handover Requests (TCHH) (Excluding Directed Retry) (900/850-1800/1900) + Outgoing Internal Inter-Cell Handover Requests (TCHH) (Excluding Directed Retry) (1800/1900900/850) + Outgoing Internal Inter-Cell Handover Requests (Directed Retry) (900/850-900/850) + Outgoing Internal Inter-Cell Handover Requests (Directed Retry) (1800/1900-1800/1900) + Outgoing Internal Inter-Cell Handover Requests (Directed Retry) (900/850-1800/1900) + Outgoing Internal Inter-Cell Handover Requests (Directed Retry) (1800/1900-900/850) .(Outgoing External Inter-Cell Handover Requests (SDCCH) (Excluding Directed Retry) (900/850-900/850) + Outgoing External Inter-Cell Handover Requests (SDCCH) (Excluding Directed Retry) (1800/1900-1800/1900) + Outgoing External Inter-Cell Handover Requests (SDCCH) (Excluding Directed Retry) (900/850-1800/1900) + Outgoing External InterCell Handover Requests (SDCCH) (Excluding Directed Retry) (1800/1900-900/850) + Outgoing External Inter-Cell Handover Requests (TCHF) (Excluding Directed Retry) (900/850-900/850) + Outgoing External Inter-Cell Handover Requests (TCHF) (Excluding Directed Retry) (1800/19001800/1900) + Outgoing External Inter-Cell Handover Requests (TCHF) (Excluding Directed Retry) (900/850-1800/1900) + Outgoing External Inter-Cell Handover Requests (TCHF) (Excluding Directed Retry) (1800/1900-900/850) + Outgoing External Inter-Cell Handover Requests (TCHH) (Excluding Directed Retry) (900/850-900/850) + Outgoing External Inter-Cell Handover Requests (TCHH) (Excluding Directed Retry) (1800/1900-1800/1900) + Outgoing External Inter-Cell Handover Requests (TCHH) (Excluding Directed Retry) (900/850-1800/1900) + Outgoing External Inter-Cell Handover Requests (TCHH) (Excluding Directed Retry) (1800/1900-900/850) . CH313 . we can find that the formula for the call drop ratio on TCH (excluding handover) is the same for the BSC32 and the BSC6000.(A312Aa + A312Ca + A312Da + A312Ea + A3127A + A3127C + A3127D + A3127E + A3128A + A3128C + A3128D + A3128E + (H3047 + H3048 + H3247 + H3248 + H3447 + H3448)) × 100% Call Drop Ratio on TCH (Excluding Handover) = (M3100A + M3100B + M3100C + M3200A + M3200B + M3200C + M3101A + M3101B + M3101C + M3101D + M3101E + M3201A + M3201B + M3201C + M3201D + M3201E + M3102 + M3202 + M313 + M323 + H3027Ca + H3028Ca + H3127Ca + H3128Ca + H3327Ca + H3328Ca + H3429Ca + M312 + M322 + M314 + M324 + M315 + M325 ) / ( (R3307A + R3308A) . Because there are few call drops on TCH in very early .+Outgoing External Inter-Cell Handover Requests (Directed Retry) (900/850-900/850) + Outgoing External Inter-Cell Handover Requests (Directed Retry) (1800/1900-1800/1900) + Outgoing External Inter-Cell Handover Requests (Directed Retry) (900/850-1800/1900) + Outgoing External Inter-Cell Handover Requests (Directed Retry) (1800/1900-900/850) . There is an index in the numerator of the formula for the call drop ratio on TCH (including handover) of the BSC32: Call drops on TCH in very early assignment. but the call drop ratio on TCH (including handover) of the BSC32 is different from the call drop ratio on TCH (excluding handover) of the BSC6000.(R3307B + R3308B + R3307C + R3308C) + (A3100A + A3100B + A3100C + A3100D + A3100E + A3100F + A3100G + A3100H + A3100I) .(Failed Outgoing External Inter-Cell Handovers (SDCCH) (900/850-900/850) + Failed Outgoing External Inter-Cell Handovers (SDCCH) (1800/1900-1800/1900) + Failed Outgoing External Inter-Cell Handovers (SDCCH) (900/850-1800/1900) + Failed Outgoing External Inter-Cell Handovers (SDCCH) (1800/1900-900/850) + Failed Outgoing External Inter-Cell Handovers (TCHF) (900/850-900/850) + Failed Outgoing External Inter-Cell Handovers (TCHF) (1800/1900-1800/1900) + Failed Outgoing External Inter-Cell Handovers (TCHF) (900/850-1800/1900) + Failed Outgoing External Inter-Cell Handovers (TCHF) (1800/1900-900/850) + Failed Outgoing External Inter-Cell Handovers (TCHH) (900/850-900/850) + Failed Outgoing External Inter-Cell Handovers (TCHH) (1800/1900-1800/1900) + Failed Outgoing External Inter-Cell Handovers (TCHH) (900/8501800/1900) + Failed Outgoing External Inter-Cell Handovers (TCHH) (1800/1900-900/850) + Failed Outgoing External Inter-Cell Handovers (Directed Retry) (900/850-900/850) + Failed Outgoing External Inter-Cell Handovers (Directed Retry) (1800/1900-1800/1900) + Failed Outgoing External Inter-Cell Handovers (Directed Retry) (900/850-1800/1900) + Failed Outgoing External Inter-Cell Handovers (Directed Retry) (1800/1900-900/850))))) × 100% Formula of the BSC6000 with short index names: Call Drop Ratio on TCH (Including Handover) = (M3100A + M3100B + M3100C + M3200A + M3200B + M3200C + M3101A + M3101B + M3101C + M3101D + M3101E + M3201A + M3201B + M3201C + M3201D + M3201E + M3102 + M3202 + M313 + M323 + H3027Ca + H3028Ca + H3127Ca + H3128Ca + H3327Ca + H3328Ca + H3429Ca + M312 + M322 + M314 + M324 + M315 + M325 ) / ( (R3307A + R3308A) .(A312Aa + A312Ca + A312Da + A312Ea + A3157A + A3157C + A3157D + A3157E + A3158A + A3158C + A3158D + A3158E) + CH323 + CH343 .(R3307B + R3308B + R3307C + R3308C) + (A3100A + A3100B + A3100C + A3100D + A3100E + A3100F + A3100G + A3100H + A3100I) .CH333 ) × 100% Summary formula of the BSC6000: Call Drop Ratio on TCH (including handover) = Call Drops on TCH / (Successful TCH Seizures (Signaling Channel) + Successful TCH Seizures (Traffic Channel) + Successful TCH Seizures in TCH Handovers (Traffic Channel)) × 100% = CM33 / (K3023 + K3013A + K3013B) × 100% Call Drop Ratio on TCH (excluding handover) = Call Drops on TCH / Successful TCH Seizures (Traffic Channel) × 100% = CM33 / K3013A After comparing the formulas of the BSC32 and those of the BSC6000 given above. there is slight difference between the call drop ratio (including handover) of the BSC32 and that of the BSC6000. 1. Because there are few call drops on TCH in very early assignment. the call drop ratio on TCH (including handover) has slight difference from the call drop ratio on TCH (excluding handover) in the numerator.assignment. Therefore.3 Measurement Time Points Figure 1 Channel seizure in the immediate assignment procedure Figure 2 Channel seizure in the assignment procedure .3. the value of the call drop ratio on TCH (including handover) is smaller than the value of the call drop ratio on TCH (excluding handover). but the denominator of the call drop ratio on TCH (including handover) has one more index than that of the call drop ratio on TCH (excluding handover): Successful TCH Seizures in TCH handovers. the BTS sends an ERROR INDICATION message to the BSC because of TCH radio link layer connection exceptions.Figure 3 Channel seizure in the internal handover procedure of the BSC Figure 4 Channel seizure in the incoming BSC handover procedure Where: TCH-SUCC+TCH-SUCC-A+TCH-SUCC-B+TCH-SUCC-C: Successful TCH seizures (all) TCH-SUCC-A: Successful TCH seizures TCH-SUCC: Successful TCH seizures in very early assignment Measurement time points of the call drop ratio on TCH: When the TCH serving as the traffic channel is seized. . 1 KPI Definition of Ericsson 1. The target cell sends the Inter Clear Request (cause value: Handover Failure) message to the source cell. We count the number of CLEAR REQUEST messages sent by the BSC to the MSC after ASSIGNMENT COMPLETE or HANDOVER COMPLETE is sent. the BTS sends a CONNECTION FAILURE INDICATION message to the BSC because of TCH radio link failure or hardware failure or other reasons. The BSC starts to measure the call drop ratio on TCH.1 Definition of the Formula The call drop ratio on TCH is defined as follows in the document R12 Radio Network Statistics of Ericsson: . a call drop will occur. a call drop occurs. When the TCH serves as the traffic channel and the system initiates BSC internal handover.4 Other Definition Modes of the KPI The following competitor analysis is based on the following version information: Ericsson: R12 Radio Network Statistics Nokia: Radio Network monitoring formulas for Phase 8th S9 BSC-Measurement Siemens: SBS Key Performance Indicators for 6. the handover fails and the MS returns to the old channel. AM/CM network communication fails for the target cell or the AM/CM network communication times out. When the TCH serves as the traffic channel. When the TCH serves as the traffic channel and the system initiates incoming BSC handover. When the TCH serves as the traffic channel and the system initiates BSC internal handover.4. Upon receipt of the message. the non-Directed Retry source cell does not receive the Inter Clear Request message (Cause value: HANDOVER COMPLETE) from the target cell within the specified time. When the TCH serves as the traffic channel and the system initiates BSC internal handover. When the TCH serving as the traffic channel is seized. As a result. The BSC starts to measure the call drop ratio on TCH in the source cell.1. The BSC starts to measure the call drop ratio on TCH after the timer expires. When the TCH serves as the traffic channel and the system initiates outgoing BSC handover. As a result. The BSC starts to measure the call drop ratio on TCH in the source cell. When the TCH serves as the traffic channel and the system initiates BSC internal handover. the radio resources of the calls with a lower priority on the TCH may be preempted by the calls with a higher priority. There is no response for AM/CM network communication upon timeout or the AM/CM network communication fails to be executed.4. The BSC starts to measure the call drop ratio on TCH. 1. If both the BSC and the MSC support pre-emption when the TCH serves as the traffic channel. the BSC starts the TREESTABLISH timer. the BSC starts the TREESTABLISH timer. the source cell does not receive the Clear Command message (cause value: HANDOVER COMPLETE) from the MSC (T8 expires). The BSC starts to measure the call drop ratio on TCH. The BSC starts to measure the call drop ratio on TCH. The BSC starts to measure the call drop ratio on TCH in the source cell. the target cell does not receive the HANDOVER COMPLETE message within the specific time. the target cell does not receive the HANDOVER COMPLETE message within the specified time and so sends the Inter Clear request message (cause value: Handover Failure) to the source cell. Upon receipt of the message. The BSC starts to measure the call drop ratio on TCH after the timer expires.0 Motorola: R7 MAINTENANCE INFORMATION GSM STATISTICS APPLICATION 1. The source cell releases the terrestrial connection and then starts AM/CM network communication again. the RSL link of the TRX where the TCH resides is broken. 4. If the BSC has already sent the CLEAR REQUEST message before receiving the CLEAR COMMAND message.4.1. 1. 1.4.Where: T_DR_S: Call drop ratio on TCH TN_DROP: The number of call drops on TCH.4. The denominator is the same as the denominator of our formula for the call drop ratio on TCH (excluding handover). Therefore. 1.1 Definition of the Formula The call drop ratio on TCH is defined as follows in the document Radio Network monitoring formulas for Phase 8th S9 BSC-Measurement of Nokia: Where: . the CLEAR COMMAND message will not be counted in the number of call drops on TCH.2 Analysis In the formula of Ericsson.2 KPI Definition of Nokia 1. the numerator covers more sub-indexes than that of our formula. The call drop ratio on TCH calculated with our formula will be lower than that calculated with the formula of Ericsson under the same network conditions. N_CALLS: The number of calls successfully initiated in the current cell. the numerator also includes the CLEAR COMMAND message that carries a cause value other than “Call Control” or “Handover Success” from the MSC. The measurement starts when the BSC sends a CLEAR REQUEST message or receives a CLEAR COMMAND message that carries a cause value other than “Call Control” or “Handover Success” from the MSC.3 Substitute Formula of Huawei Because the call drop ratio on TCH calculated with our formula will be lower than that calculated with the formula of Ericsson under the same network conditions. we can directly use the recommended formula in comparing our call drop ratio with that of Ericsson.2.1. It includes the number of directed retries initiated by the current cell to other cells and does not include the number of directed retries initiated by other cells to the current cell. The denominator of Siemens formula (1) is the same as that of our formula for the call drop ratio on TCH (including handover). Comparatively.2 Analysis In the formula of Nokia.4. 1. The sub-indexes include the channel activation attempts in call establishment and the TCH activation attempts in incoming cell handover.3. In the formulas of Siemens. while the denominator in Siemens formula (2) contains an additional index “Successful Incoming Cell Handovers” and does not have the index “Successful Outgoing Cell Handovers” as compared with our formula for the call drop ratio on TCH (excluding handover). When the number of successful outgoing cell handovers is equivalent to the number . The numerator in the formula of Nokia counts all the failed TCH seizures after channel activation and the call drops after TCH seizure.4. the formulas of Siemens exclude the call drops in the incoming BSC handover procedure.1. 1.3. and the call drops in the outgoing BSC handover procedure. the call drops in the internal handover procedure of the BSC.2 Analysis The definition in Siemens formula (1) is similar to our formula for the call drop ratio on TCH (including handover). the call drops in the intra-cell handover procedure. the system starts measuring the sub-indexes in the denominator after the BSC sends the TCH activation command to the BTS. but exclude the number of outgoing cell handovers.3 Substitute Formula of Huawei Because the call drop ratio on TCH calculated with our formula will be lower than that calculated with Nokia formula. the numerator “TCHDrop” covers the call drops in stable state.3 KPI Definition of Siemens 1. The call drops in the outgoing BSC handover procedure are calculated as follows: Outgoing BSC handover commands .4. the call drop ratio on TCH (excluding handover) calculated with our formula will be lower than that calculated with the formula of Nokia.4. Because the failed TCH seizures after channel activation are also counted as call drops. but excludes the call drops in incoming BSC handover. the number of call drops on TCH counted by Nokia is more than the actual number of CLEAR REQUEST messages sent by the BSC. Compared with our formula. we can use the recommended formula in comparing our call drop ratio on TCH with the formula of Nokia.4. while the definition in Siemens formula (2) is similar to our formula for the call drop ratio on TCH (excluding handover).2.2.1 Definition of the Formula Siemens has two methods to define the call drop ratio on TCH: (1) (2) Where: TCHDropRate: Call drop ratio on TCH CallDropRate: Call drop ratio TCHDrop: Call drops on TCH SUCTCHSE: Successful TCH seizures (All) IntraCellHOSucc: Successful intra-cell handovers InterCellHOSucc: Successful outgoing cell handovers InterBSCHOSucc: Successful outgoing BSC handovers 1.Successful outgoing BSC handovers – The times of reconnection to old channels in the case of outgoing BSC handover failure. we can utilize software parameter control to exclude the call drops in the incoming BSC handover procedure from the measurement. In sum. the call drop ratio calculated with Siemens formula (1) will be slightly lower than that calculated with our formula for the call drop ratio on TCH (including handover). They are defined as follows: Cell level: BSC level: .3. This formula is equivalent to Siemens formula (2). 1. In this way.4. our recommended formula for the call drop ratio on TCH (including handover) is equivalent to Siemens formula (1). The call drop ratio calculated with Siemens formula (2) will also be slightly lower than that calculated with our formula for the call drop ratio on TCH (excluding handover) when the number of successful outgoing cell handovers is equivalent to or less than the number of successful incoming cell handovers.4 KPI Definition of Motorola 1.of successful incoming cell handovers. BSC level and network level. the denominator of Siemens formula (2) is equivalent to the denominator of our formula for the call drop ratio on TCH (excluding handover). because the call drops in Siemens formula (1) do not cover the call drops in the incoming BSC handover procedure. we can use this formula: Call Drops on TCH / (Successful TCH Seizures + Successful Incoming Internal Inter-Cell Handovers + Successful Incoming External Inter-Cell Handovers .4.1 Definition of the Formula There are three levels for the call drop ratio on TCH as defined in the document R7 MAINTENANCE INFORMATION GSM STATISTICS APPLICATION of Motorola: Cell level. 1.4. When the call drops in the incoming BSC handover procedure are excluded from the measurement through software parameter control.4.Successful Outgoing Internal Inter-Cell Handovers Successful Outgoing External Inter-Cell Handovers).3 Substitute Formula of Huawei When comparing our call drop ratio with that of Siemens. for the networks of mobile communication companies. The denominator in the network-level formula of Motorola only measures successful TCH seizures in the assignment procedure including those in Directed Retry. Motorola only counts the CLEAR REQUEST messages following the ASSIGNMENT COMMPLETE message as call drops on TCH in the networks of mobile communication companies. It does not cover successful TCH seizures in the intra-cell handover procedure. the BSC will send a CLEAR REQUEST message to the BTS during L2 connection release of the MS. The value calculated with the cell-level formula should be the smallest. when the BSC does not send CLEAR REQUEST message to the BTS upon receipt of the Handover Command or Clear Command message during the connection release of the MS. It does not cover successful TCH seizures in the internal handover procedure of the BSC. . we cannot judge whether the call drop statistics of Motorola are falsified by simply checking whether the number of call drops on TCH is equal to the number of CLEAR REQUEST messages in the traffic statistics of Motorola. That is.Network level: Where: DROP_CALL_RATE: Call drop ratio on TCH RF_LOSSES_TCH: Call drops on TCH due to RF reasons. BSC-level and network-level formulas of Motorola for the call drop ratio on TCH. As can be seen from the cell-level. including all the call drops in the stable state due to RF reasons INTRA_CELL_HO[INTRA_CELL_HO_LOSTMS]: Call drops in the intra-cell handover procedure OUT_INTRA_BSS_HO[OUT_INTRA_BSS_HO_LOSTMS]: Call drops in the outgoing internal inter-cell handover procedure OUT_INTER_BSS_HO[OUT_INTER_BSS_HO_LOSTMS]: Call drops in the outgoing external inter-cell handover procedure TOTAL_CALLS: Successful assignments IN_INTRA_BSS_HO[IN_INTRA_BSS_HO_SUCC]: Successful incoming internal inter-cell handovers IN_INTER_BSS_HO[IN_INTER_BSS_HO_SUCC]: Successful incoming external inter-cell handovers ASSIGNMENT_REDIRECTION: Successful directed retries 1. However. Therefore. On the contrary. the statistics of call drops on TCH of Motorola only exclude the call drops in the incoming BSC handover procedure as compared with us. but Motorola does not count this message as a call drop.2 Analysis The call drops on TCH of Motorola do not correspond one to one with CLEAR REQUEST messages.4. so as to satisfy the evaluation requirements of mobile communication companies. The denominator in the BSC-level formula of Motorola covers successful TCH seizures in the assignment procedure and successful TCH seizures in the incoming BSC handover procedure. For instance. Motorola will count it as a call drop. The denominator in the cell-level formula of Motorola covers successful TCH seizures in the assignment procedure and successful TCH seizures in the incoming cell handover procedure.4. the call drop ratio on TCH calculated with the network-level formula of Motorola should be higher than that calculated with its cell-level and BSC-level formulas. For the network-level KPI. We can simply judge whether the call drop statistics provided by a competitor are falsified through signaling tracing and the measurement method of the competitor. For the BSC-level KPI.Successful internal inter-cell handovers of the BSC). We must determine the formula to be used according to the actual formula used for the network. we can use the following formula for the cell-level KPI: Call drops on TCH / (Successful TCH seizures (all) – Successful TCH seizures in very early assignment). The substitute formula should be consistent with the formula of Motorola for the call drop ratio on TCH for the networks of mobile communication companies. At present. In the existing version. Compare the number of CLEAR REQUEST messages among the A interface messages with the number of call drops in the traffic statistics of the competitor. At present different equipment manufacturers and operators have different definitions for the calculation formula of this KPI (see sections 1. 2 KPI Test Method The call drop ratio on TCH is a traffic measurement index and can be obtained by registering or reporting the relevant traffic measurement task. the samples obtained in the drive test are limited and the test route is not allinclusive.5 Suggestions on KPI Optimization After comparing our measurement method with the measurement methods of competitors for the call drop ratio on TCH. we can use this formula: Call drops on TCH / (Successful TCH seizures (all) – Successful TCH seizures in very early assignment .1. because in the drive test the call drop ratio is measured through sampling. a comparison between our call drop ratio and that of our competitors is needed in many network relocation cases. we can exclude the call drops in the incoming BSC handover procedure from the measurement through software parameter control or traffic statistic customization.3 Substitute Formula of Huawei When comparing our call drop ratio on TCH with that of Motorola. But the call drop ratio on TCH obtained through the drive test is for reference only and greatly differs from the actual call drop ratio. register as detailed sub-indexes as possible during the actual test and then combine the sub-indexes into the most favorable formula. .4. Therefore.3“Recommended Formula” and 1. and the KPI may vary with the specific calculation formula. we can use the recommended formula.4. For the call drop rate that reflects subscribers’ feeling. we cannot determine which substitute formula should be used because we cannot determine the specific measurement method of Motorola for the call drop ratio on TCH. If the two have obvious difference. The method is given as follows: Trace the A interface messages in a measurement interval and count the CLEAR REQ messages in the statistics. we can use the formula: Call drops on TCH / (Successful TCH seizures + Successful incoming cell handovers – Successful outgoing cell handovers. 1.4“Other Definition Modes of the KPI” for details). This formula places an emphasis on the probability of call drops on the established TCH in the cell and is better than the recommended formula when the successful incoming cell handovers are more than the successful outgoing cell handovers. When comparing our call drop ratio on TCH with that of Motorola for the networks of mobile communication companies. we recommend that the call drops in the incoming BSC handover procedure be excluded from the call drops on TCH. then possibly the traffic statistics are falsified. It can also be obtained by the drive test method. 3“Recommended Formula”.Note: Because different competitors have different measurement methods.57% 1. 3 KPI Baseline 3.15% 1.90% 1. 3.3“Recommended Formula”.57% 1.2 Test Environment Constraints Ensure that the network optimization has been completed and that there is no engineering construction error before the test. The difference between the two values does not necessarily mean that the traffic statistics are falsified. the baseline of the BSC32 is used as the reference baseline. .64% Note: The above baseline data is based on the version BSC6000V9R1 and the calculation results are obtained by using the recommended calculation formula given in section 1.2 Baseline of Call Drop Ratio on TCH of the BSC6000 KPI Name Class A Network Class B Network Class C Network Class D Network Call drop ratio on TCH (including handover) 0.51% 0.15% 1.68% 0.1 Test Method Constraints 4. the call drops on TCH do not necessarily correspond one to one with the CLEAR REQUEST messages.1 Baseline of Call Drop Ratio on TCH of the BSC32 KPI Name Class A Network Class B Network Class C Network Class D Network Call drop ratio on TCH (including handover) 0. 4 Constraint Analysis 4. Because at present there are few BSC6000 sites.51% 0.24% 0.77% Call drop ratio on TCH (excluding handover) 0. This method only provides a way for us to make preliminary judgment.68% 0.64% Note: The above baseline data is based on the version G2BSC32V300R007C01 and the calculation results are obtained by using the recommended calculation formula given in section 1. The relevant data will be updated later along with the increase of sites.24% 0.77% Call drop ratio on TCH (excluding handover) 0.90% 1. Equipment Plenty of terrestrial resources are unavailable or a lot of equipment fails during the test. Antenna and feeder system Traffic The coverage is poor because of different pitch angles of the two antennas when single-polarized antenna is used.4“Other Definition Modes of the KPI” for details.Data Configuration Reference -. The actual network traffic is unevenly distributed in the test environment. or high frequency reuse due to frequency resource shortage. 4.3 KPI Definition Constraints Because competitors and operators may have different requirements for the calculation formula of the call drop ratio on TCH from us. There is obvious cross coverage in the test environment.4 Parameter Constraints Whether the relevant parameter settings of the call drop ratio on TCH are reasonable will directly influence the network indexes. Refer to sections 1.3“Recommended Formula” and 1. The voltage standing wave ratio (WSWR) is high due to factors of the feeder itself. 4. we should carefully analyze the formula differences during the bid answering process and give an analysis of the possible impact of such differences on the call drop ratio on TCH. This will lower the transmit power and receiving sensitivity. and such problems cannot be solved by network optimization. Transmission Poor quality of transmission lines such as Abis interface links and A interface links or instable transmission links due to various reasons in the test environment. and cause poor coverage and call drops. The following parameters will influence the call drop ratio on TCH: . which inevitably causes severe internal interference to the network. Interference There is inevitable interference from other networks or repeater stations in the test environment. low coverage level or cross coverage in the test environment.Network Planning Parameters for the specific parameter setting ranges.The committed baseline values cannot be guaranteed in the following cases when the above prerequisite is satisfied: Test Environment Coverage Problem Description There are problems such as blind spots. Refer to M900/M1800 Base Station Controller -. If the set value is too large. we can view the available call drop signaling to look for the signaling flows containing the Disconnect. we can reduce the number of call drops in the traffic statistics. If we cannot view the data on the MSC side. call drops will occur when the Rx level of the MS suddenly fades a lot due to reasons such as geographical conditions. Cell attribute table: SACCH multiframe count Its function is the same as the radio link invalidity counter. If we change the values of T305 and T308 to smaller ones.5 Function Constraints The following functions will influence the call drop ratio on TCH: . The two timers are located on the MSC side. and RACH busy threshold T305 & T308 These indexes relate to coverage and the balance between the uplink and the downlink. the MSC will send a CLEAR COMMAND message to the BSC before the CLEAR REQUEST message is sent. unbalance between the uplink and the downlink will occur and call drops are also likely to occur if they are unreasonably set. the system will count this as a call drop.Parameter Configuration Requirements System message parameter table: Radio link invalidity counter If the set value is too small. the frequency utilization will be lowered. If the CLEAR REQUEST message sent by the BSC already reaches the MSC before T305 and T308 expire. so we should ensure that the cell adjacency definition is complete. BA2 table Handover failure will occur to cause call drops if the cell adjacency definition is incomplete. the call is regarded as being normally released). the network will be unable to release relevant resources until the radio link times out. We can set this counter to a larger value for the border areas with little traffic and set it to a smaller value for the areas with high traffic during the parameter setting. Refer to the following attachment for other parameter constraints: GSM BSS TCH掉话率参数控制策略 4. As a result. However. RACH minimum Rx level. till the MSC gets a response from the BSC. till the MSC gets a response from the BSC. T308 starts when the MSC sends a RELEASE message to the BSC. Release and Clear Command messages continuously sent by the MSC to the BSC (the error cause value of the Disconnect and Release messages is “Recovery on Timer Expiry”). Subscribers under poor coverage can easily access the network and thus call drops are likely to occur if these indexes are set to too small values. In this way. Then we can calculate the values of T305 and T308 according to the time difference of the records. even if the speech quality is far more unacceptable. System message parameter table: MS minimum Rx level. so as to forcibly release the connection (in this case. T305 starts when the MSC sends a DISCONNECT message to the BSC. Intelligent overlay cell underlay- When the intelligent underlay-overlay cell function is enabled. We recommend that this function be enabled in areas where the traffic is high. On the contrary. Where the coverage is poor. However. This function may bring certain interference. PBT. We recommend that these functions be enabled according to the local coverage state. if we adjust the settings of coverage-related parameters so as to reduce call drops on TCH. This can obviously reduce the possibility of call drops during the handover in areas where the traffic is high but the effect is not obvious for areas where the traffic is low. At present. these functions can be used to improve the call drops caused by coverage. transmit diversity. We recommend that attention be paid to call drops and appropriate cell parameters be selected when this function is enabled. this function is only implemented by the BSC32. the subscribers under poor coverage will hardly be able to access the network and respond to paging and so the paging success ratio will decrease. . we recommend that the frequency hopping function be enabled when the frequency resources are scarce. Frequency hopping When the frequency resources are scarce. the system will raise the power before initiating the handover. the probability of call drops in areas with poor coverage will increase and thus the call drop ratio on TCH will deteriorate. so that the subscribers under poor coverage can also respond to paging and make conversation. Power raising before handover When this function is enabled. call drops will easily occur due to inconsistent coverage between the overlay and the underlay. We recommend that these functions be enabled so as to reduce the call drop ratio on TCH. 4. frequency hopping can flatten the interference and thus reduce the call drops caused by interference. For this reason. we should reduce the values of coverage-related parameters such as RACH minimum access threshold.Function Requirements Power control and DTX These functions can reduce the interference to the whole network and thus reduce the call drops caused by interference. four-diversity reception and tower-top amplifier These functions help enhance the coverage.6 Inter-KPI Constraints The following KPI and the call drop ratio on TCH can influence each other: KPI Paging success ratio Possible Mutual Influence To improve the paging success ratio. 1 Baseline Commitments There are two scenarios in the GSM network: Network relocation and new construction of a network. The worsening of the call drop ratio on TCH caused by bursty bulky traffic should be separately considered. The worsening of this KPI caused by accidental equipment failure. Assess the influence of the difference on the final KPI.4. Almost all equipment in the network is products of Huawei. Analyze the calculation formulas given by other vendors for the call drop ratio on TCH and the measurement time points of various sub-indexes. the following preparations should be made before the relocation: 1) 2) 3) 4) Analyze the differences between the calculation formula provided by the operator and our calculation formula. Compare them with our calculation formula and measurement time points for the call drop ratio on TCH. this document gives the commitments for the two scenarios separately. The specific influence is listed below: Version TRX and FRU versions of the BTS Influence The version inconsistency of the two can cause a high call drop ratio. Refer to the description of baseline constraints if the above conditions cannot be satisfied. The specific conditions that may influence the KPI commitments include but are not limited to the following: The definition method of the KPI is consistent with that of Huawei. 5. The test method of the KPI. .1 Baseline Commitments in the Event of Network Relocation In the event of network relocation. is consistent with that of Huawei. The network environment conforms to the requirements of Huawei. The call drop ratio on TCH is a KPI measured after the network is ultimately delivered and normally put into operation. 5 Baseline Commitments The KPI baseline is the commitments of Huawei to the KPI for various types of networks defined by Huawei according to the above KPI definition when the network uses totally Huawei products and the default parameters. As the requirements of operators for the KPI are not completely the same. including the test tools. so as to find the differences.7 Version Constraints Unreasonable matching of some versions will also cause the call drop ratio on TCH to rise. 5. Then analyze and evaluate the differences between the evaluation formula provided by the operator and our baseline formula.1. Evaluate the statistical result deviations caused by the differences and compare the differences according to the actual conditions of the network to be relocated. natural environment factors or man-made factors should be excluded. Select a calculation formula with the least difference to match the calculation formula provided by the operator. test steps and calculation methods. the traffic statistics are not authentic. interference. 6 KPI Optimization Means To be supplemented. Compare the number of CLEAR REQUEST messages in the signaling with the number of call drops in the traffic statistics. we should commit the KPI with reference to the KPI baseline when the network type and scenario basically match the actual ones. . The factors that will influence this KPI include coverage. and handover.1. If there is obvious difference between the two.2 Baseline Commitments in the Event of New Network Construction In the event of new network construction.5) Analyze if the traffic statistics provided by other vendors are authentic if the call drop ratio of the network is particularly low. provided that the committed KPI baseline is not higher than the baseline for the specific type of the network. Trace the A interface signaling of one measurement interval and count the number of CLEAR REQUEST messages sent after the assignment is complete in the signaling. balance between the uplink and the downlink. and ensuring reasonable setting of handover relations and handover parameters when the KPI required by the operator is superior to the baseline value. We should add restrictive conditions and optimize the calculation formula. guaranteeing the balance between the uplink and the downlink. 5. we should first consider improving coverage.3 Risk Analysis Risk analysis needs to be performed for the bid in which the committed baseline exceeds our baseline capability.1. Therefore. reducing interference. 5. Combine the corresponding influencing factors on the above basis to make the corresponding KPI commitments.
Report "1. Baseline Specifications for GSM BSS Network Performance KPIs (Call Drop Ratio on TCH)"