ROBI 3G Optimization Project- KPI Verification

Transcription

1 ROBI 3G Optimization Project- KPI Verification Copyright 2014 TEOCO Corporation - All rights reserved. No part of this work, which is protected by copyright, may be reproduced in any form or by any means - graphic, electronic or mechanical, including photocopying, recording, taping or storage in an information retrieval system - without the written permission of the copyright owner.

2 KPI Verification Network Performance ROBI 3G Optimization Project KPI Verification Page 2 of 17

3 Contents 1 Document Control History Reviewers Document Acceptance Signature Block Objective Input Data Verification Process Introduction Capabilities Radio Network KPI Introduction Quality of Service RAN Performance Observability Model Definitions and Explanations KPI Area Information KPI Formulas Accessibility Retainability Mobility Integrity of 17

4 1 Document Control 1.1 History Version Date Name Revision 1 16-Dec Dec Jan Chandan Kr Singh Chandan Kr Singh Chandan Kr Singh Section 2, 3 & 4 added 1.2 Reviewers Reviewer Date Feedback Fouad Benallal 30-Dec Document Acceptance Signature Block This Statement of Work is accepted by <Client> in full without amendments and exclusions Signatory Organization Role Signature Date 3 of 17

5 2 Objective This document describes the Performance Statistics functionality in the WCDMA RAN. It explains the Radio Network Formulas. The description of the statistics counters is not given in this document. It can be found in the node CPI Managed Object Model RNC, Performance Statistics - Flowcharts for Counters, Performance Statistics and Performance Statistics - Flowcharts for Counters. This document is written for the following group of personnel: engineers working with mobile network optimization, operation and maintenance personnel and management. It is assumed that users of this document are familiar with the basic concepts and principles of the Ericsson WCDMA Systems. Basic knowledge of Radio Network functions is recommended. 3 Input Data S No Input Data Date Remarks 1 KPI Global Formula 2 ROBI KPI formula from BO 16-Dec Dec- 14 For comparison with ROBI Formula For comparison with Global formula 4 Verification Process

6 The process followed for Verification:- Observation/Discrepancy share with ROBI Need to verify again after correction, if any Conclusion Form Global standard formula to BO formula for all respevtive KPI's KPI Formula Verification Global standard KPI formula (Ericsson Standard) KPI formula used by ROBI in BO Data Collection 5 Introduction This user description presents the Key Performance Indicators (KPI) for WCDMA RAN for the purpose of measuring the subscriber perceived quality. These quality metrics are divided into four areas: Accessibility, Retainability, Integrity and Mobility.

7 6 Capabilities Monitoring the RAN performance is a very important task for different categories of users, such as operation and maintenance personnel, network engineers, and management. The Radio network KPI can be used for the following tasks: Rapidly detecting unacceptable performance in the network, enabling the operator to take immediate actions to preserve the quality of the network Troubleshooting on cell clusters of interest Monitoring and optimizing the radio network performance to have a better subscriber-perceived quality or a better use of the installed resources Providing radio network planners with the detailed information needed for the dimensioning and configuration of the network for optimal use 7 Radio Network KPI 7.1 Introduction

8 This chapter provides, the Key Performance Indicators (KPI) for WCDMA RAN. These quality metrics are divided into four areas: Accessibility, Retainability, Integrity and Mobility Quality of Service Accessibility The ability of a service to be obtained, within specified tolerances and other given conditions, when requested by the user. It is the percentage of call attempts made by the end-user that are successful. Call setup failures can be blocked calls due to lack of network resources on various levels, for example Transmission Network, Channel Elements, DL Power and so on, or other reason that prevented a successful call setup, for example radio link problem, signaling failure and so on. Retainability The probability that a service, once obtained, will continue to be provided under given conditions for a given time duration. The percentage of the successfully call setups that were retained during the whole conversation (session) and terminated by the user. The standard KPI for retainability is the Dropped Call Rate. On cell level it is defined as the number of dropped calls in the cell divided by the total number of calls terminated (by end-user or dropped) in the cell. Integrity The degree to which a service is provided without excessive impairments, once obtained The Service Integrity represents the quality experienced by the user during the call or session. This is very difficult to measure from a system point-of-view and rough measures have to be used, based on RBS and UE measurements. BLER is used as an indication of the service integrity for CS services, but do not show the quality experienced by the enduser. For PS services are BLER and throughput used as service quality indicators RAN Performance Observability Model The RAN Performance Observability model used by Ericsson is described below. The three ITU-T areas Accessibility, Retainability and Integrity are complemented with Mobility. These are the main four areas for performance monitoring on macro or KPI level of an UTRAN network and

9 should be fulfilled by counters in PM. The statistics will be given per service when applicable. UTRAN Observability Model 8 Definitions and Explanations In the following sections, the majority of the equations are written per UtranCell. The user may choose to aggregate the counters over a group of cells and use the same equations to calculate the KPI over a cluster of cells, one RNC, or multiple RNCs. Basically, the user should replace UtranCell.pmXYZ with the following in each equation to get the metric over a larger area: pmxyz(group) = Σ(UtranCell Group) UtranCell.pmXYZ

10 The same aggregation can be performed over time. Each counter is reported every 15 minutes. The user may choose to aggregate them over an hour, 24 hours, or as the user wishes. In that case, the user can replace the pmxyz(utrancell) with its time aggregated sum. Sum-samples counters are aggregated over time as: Σ(MeasPeriod ) pmsumxyz pmxyz(time)= Σ( MeasPeriod) pmsamplesxyz All 15 minute periods for counter pmsumxyz are added together and divided with the sum for counter pmsamplexyz for the same time period. Sum-sample counters are object aggregated as: Utran Cell. pmsamplesxyz Average(UtranCell Group) Σ(UtranCell Group)UtranCell. pmsumxyz pmxyz (Group )= The counter pmsumxyz is added together for a group of cells (for the same 15 minutes period) and divided with the average for counter pmsamplesxyz for the same group of cells. If Sum-samples counters are both time and object aggregated, the following formula should be used: pmxyz (Time Group )= Σ(UtranCell Group) Σ( MeasPeriod)UtranCell. pmsumxyz A verage (UtranCell Group )[Σ ( MeasPeriod )UtranCell pmsamplesxyz] The counter pmsumxyz is summed up for the time period for each cell, then time aggregated values are added for all cells in the group. The sum is divided with the average of the time aggregated counters pmsamplesxyz, that is the counter pmsamplesxyz is summed up for the time period for each cell, then the average is taken for the cells in the group. When performing time and object aggregation it is important to first do time aggregation and then do object aggregation. Soft/Softer Handover Overhead The Handover Reduction Factor (HRF) is defined as the ratio of downlink code channel utilization for speech and the average number of users served. This metric shows how much of the radio resources (code and power) are used to support soft/softer handover in a given cell. HRF can be also calculated per RNC.

11 Xy can be any type of service, for example Speech (Sp) or Circuit- Switched 57 (CS57). Tot User Xy 100 Xy Xy HRF = Definition of PERLEN PERLEN denotes the measurement time in minutes. It is the resolution in the query PERLEN=15 for a 15-minute ROP resolution. Definition of PM_COUNT pm_count = the number of ROPs multiplied by the number of objects. It can be checked for a given counter by count (pmcountername). 9 KPI Area Information Accessibility

12 In the Accessibility area equations, RRC connection attempts are not corrected for redirections due to emergency calls. The counter pmnoofredirectedemergencycalls can be used to estimate the percentage of emergency call redirections on RNC level. To consider redirections due to inter-frequency load sharing, when the functionality is enabled, an example of equation is given in the Circuit-Switched (CS) Speech Accessibility equation. A correction is then made to eliminate duplicated CS RRC connection attempts resulting from load sharing redirection orders. An equivalent formula can be defined to calculate all services. The two first formulas below for Iu signaling success rate can be calculated on RNC level only and they can be added to PS and CS Accessibility formulas on RNC level to include also the signaling set-up success rate to the total Accessibility. All the accessibility KPIs using the pmtotnorrcconnectreqcs or pmtotnorrcconnectreqps counters do not count RRC rejections because of the flow control between the CC SP and the Module MP. The number of rejections for all RRC establishment causes is given in the pmnorejrrcconnspflowctrl counter. Mobility Soft/Softer Handover Overhead Calculation In this section, various statistics for different soft/softer handover state is calculated. These statistics could be used to measure the overhead due to soft/softer handover that have impact on cell dimensioning. The formulas does not give the amount of Ues in Soft/Softer HO in relation to total amount of Ue connections. The following table shows the radio link counters per soft/softer status of a given UtranCell. It should be noted that these counters have a low sampling rate of 1 minute and the counters should be aggregated over a sufficiently long period for statistical validity. The columns of Table 1 and Table 2 show the counters that step when the number of radio link sets is equal to the heading number. The rows of Table 1 and Table 2 show the counters that step when the number of radio links is equal to the row heading. Basically, the gauge counter corresponding to these sum and sample counters increment when the active set size is equal to the number of radio links in the counter name and the number of radio link sets in the active set is equal to the number of radio link sets in the counter name. Note: The term radio link is equivalent to a cell. The term radio link set is equivalent to the number of Iub connections or the number of node B's involved in call processing.

13 10 KPI Formulas 10.1 Accessibility 1. RRC Setup Success Rate (%) 100 pmtotnorrcconnectreqsuccess pmtotnorrcconnectreq pmnoloadsharingrrcconn 2. RAB Establishment Success Rate Speech (%) 100 pmnorabestablishsuccessspeech pmnorabestablishattemptspeech pmnodirretryat 3. RAB Establishment Success Rate PS Interactive (%) 100 pmnorabestablishsuccesspacketinteractive pmnorabestablishattemptpacketinteractive 4. RAB Establishment Success Rate PS Interactive HS (%) 100 pmnorabestablishsuccesspacketinteractivehs pmnorabestablishattemptpacketinteractivehs 5. RAB Establishment Success Rate PS Interactive EUL (%) 100 pmnorabestablishsuccesspacketinteractiveeul pmnorabestablishattemptpacketinteractiveeul

14 10.2 Retainability 1 Speech Drop Rate (%) 100 pmnosystemrabreleasespeech pmnosystemrabreleasespeech+ pmnonormalrabreleasespeech 2 Packet_HS Drop Rate (%) 100 pmnosystemrbreleasehs pmnonormalrbreleasehs+ pmnosystemrbreleasehs + pmnosuccrbreconfpsintdch + pmpsinthstofachsucc+ pmchswitchsucchsura 3 RAB Drop Rate PS Interactive EUL (%) 100 pmnosystemrbreleaseeul pmnonormalrbreleaseeul + pmnosystemrbreleaseeul+ pmnosuccrbreconfpsinteul + pmpsinthstofachsucc + pmchswitchsucceulura 10.3 Mobility 1 Speech IRAT HO Success Rate (%) 100 pmnosuccessoutirathospeech+ pmnosuccessoutirathomulti pmnoattoutirathospeech + pmnoattoutirathomulti 2 Soft HO Success Rate (%) 100 pmnotimesrladdtoactset pmnotimesrladdtoactset + pmnotimescellfailaddtoactset 3 PS IRAT (UMTS to GSM) Success Rate (%) 100 pmnooutiratccsuccess pmnooutiratccatt

15 10.4 Integrity HSDPA USER THROUGHPUT pmsumnonemptyuserbuffersspi 00>+ pmsumnonemptyuserbuffersspi 01>+ < pmsumnonemptyu EUL USER THROUGHPUT pmnoactive 2 msframeseul> 0.01 pmnoactive 10 msframeseul> + pmsumackedbitscelleultti 10>+ pmsumackedbitscelleultti 2>

16 End of Document KPI Verification