Optimization Guidelines ACCESSIBILITY Ericsson Rev01

 

  ptimization Guidelines: Accessibility in Ericsson

C NTENTS 1 INTRODUCTION.................................................... ...................................................................................................... .......................................................... ............... .............. ........ 3 . 3 2 ACCESSIBILITY................................................... .......................................................................................................... .............................................................. .............. ............. ...... 4  4 2.1 Idle Mode.................................... ...................................................... ..................................... ..................................... .................................... .................................... ..................................... ................... 4  4 2.2 Call Establishment Process......... .................. .................. .................. .................. .................. .................. .................. .................. .................. ................ ........... ......... .......... .......... ...... 4  .4

3 ACCESSIBILITY KPIs (Key Performance Performance Indicators) Indicators).................................................... ................................................................... ............... 5  5 3.1 High Level KPIs......... .................. .................. .................. .................. .................. .................. .................. .................. .................. .................. ................. ................. ................. ............ ........ ....... ... 5  5 3.1.1 Call Setup Success Rate - CSSR (%)............. ........................... ............................. ............................. ............................ ............................ ........................... ................... ............ ........... ..... 5  5 3.1.1.1 CS CSSR (%)............ ........................... ............................. ............................ ............................ ............................ ............................. ............................. ............................ ........................ ........... 5 . 5 3.1.1.2 PS CSSR (%).............. ............................. ............................. ............................ ............................ ............................ ............................. ............................. ........................ ................ ........... ....... .. 5  5 3.1.1.3 CS CSSR (%) –from P7.1-.............. ............................ ............................ ............................. ............................. ............................ .......................... ................. .......... .......... ......... .... 6  6 3.1.1.4 PS CSSR (%) – from P7.1-............. ........................... ............................. ............................. ............................ ............................ ............................ ........................... .................. ..... 6  6 3.1.2 Overall Service Accessibility - OSAC (%).............. ............................ ............................ ............................ ............................ ............................. ..................... ........... .......... ......... .... 7  7

3.2 Medium Level KPIs........ ................. .................. .................. .................. .................. .................. .................. .................. .................. .................. .................. ................ ........... ......... .......... ...... 8  .8 3.2.1 RRC Connection Success Rate (%)............. ........................... ............................ ............................. ............................. ............................ ............................ ............................ ................... ..... 8  8 3.2.1.1 RRC Connection Success Rate CS (%).............. ............................ ............................. ............................. ............................ ............................ ................... .......... ....... .. 8  8 3.2.1.2 RRC Connection Success Rate PS (%).............. ............................. ............................. ............................ ............................ ..................... ............ .......... .......... ......... .... 8  8 3.2.2 Iu Signalling Establishment Success Rate (%)............. ........................... ............................ ............................ ............................ ............................. ........................... ................ .... 8  8 3.2.2.1 Iu-CS Signalling Establishment Success Rate (%).............. ............................ ............................ ............................ ............................. ........................ ......... 9  9 3.2.2.2 Iu-PS Signalling Establishment Establishmen t Success Rate (%).............. ............................ ............................. ............................. ........................ ................ ........... ....... .. 9  9 3.2.3 NAS Signalling Signalling Establishment Establis hment Success Rate (%) –from P7.1-.............. ............................ ............................ ............................ ............................ ................... ..... 9  9 3.2.3.1 NAS CS Signalling Establishment Establ ishment Success Rate (%) – from P7.1-.............. ............................ ............................ ................... .......... ....... .. 9  9 3.2.3.2 NAS PS Signalling Establishment Establi shment Success Rate (%) – from P7.1P7.1- .............. ............................ ..................... ............ .......... .......... ......... .... 9  9 3.2.4 (RAB) Establishme Establishment nt Success Rate (%).............. ............................. ............................. ............................ ............................ ............................ ............................. ......................... ..........  9  9 3.2.5 Sending Paging Failure Rate (%) ............................. ............... ............................ ............................ ............................ ............................ ............................. ..................... ............ ............ ...... 10  10 3.2.6 Blocking Probabili Probability ty............. ........................... ............................ ............................ ............................ ............................ ............................. ............................. ............................ ........................ ............ .. 10  10 3.2.6.1 GoS Speech (%)............. ........................... ............................ ............................ ............................ ............................ ............................. ............................. ............................ ................... ..... 10  10 3.2.6.2 GoS PS (%).............. ............................ ............................ ............................ ............................ ............................. ............................. ............................ ............................ ...................... ........... ... 10  10

3.3 Failures after Admission Rate (%):......... .................. .................. .................. .................. .................. .................. .................. ................. ................. ................ ............ ...... 11  .11

4 PERFORMANCE ANALYSIS.................................................... ................................................................................. .................................... .............. ............... ........ 12 4.1 Admission Control......... .................. .................. .................. .................. .................. .................. .................. .................. .................. .................. .................. .............. .......... .......... .......... ...... 12  .12 4.1.1 Admission Policy............... ............................. ............................ ............................ ............................ ............................. ............................. ............................ ............................ ............................ ............... 12 . 12 4.1.2 Resources to be monitored ............. ........................... ............................. ............................. ............................ ............................ ............................ ......................... ................ ........... ........... ........ ... 13  13 4.1.2.1 RF Power............... ............................. ............................ ............................ ............................ ............................ ............................. ............................. ......................... ................ .......... ........... ...... 13  13 4.1.2.2 Code Tree Consumptio Consumption n.............. ............................ ............................ ............................ ............................ ............................ ............................. ........................ .............. .......... ..... 13  13 4.1.2.3 DL and UL ASE............. ............................ ............................. ............................ ............................ ............................ ............................. ........................... ................. .......... .......... ......... .... 13  13 4.1.2.4 SF Code Limit Limit (Code Hystogram) ............. ........................... ............................ ............................ ............................. ............................. ............................ ................... ..... 13  13 4.1.2.5 HSDPA and EUL connectio connections ns Limit Limit.............. ............................ ............................ ............................ ............................ ............................. ........................... .............. .. 13  13 4.1.2.6 UL and DL Channel Elements.............. ............................ ............................. ............................. ............................ ............................ ............................ ....................... .......... 13 . 13 4.1.3 RRC Admission Blocks ............... ............................. ............................ ............................ ............................ ............................ ............................. ............................. ............................ ................... ..... 13  13 4.1.4 RAB Admission Blocks............. ........................... ............................ ............................. ............................. ............................ ............................ .......................... ................. .......... .......... ........... ....... 14 . 14

 

4.2 MP Load (High processor Load)......... .................. .................. .................. .................. .................. .................. .................. .................. .............. .......... .......... .......... .......... ..... 14  14 4.3 After Admi Admission ssion........................... ............................................. .................................... .................................... ..................................... ................................................. ................................. ... 14  14 4.3.1 Failure after Admission: Iub Congestion .............. ............................. ............................. ............................ ............................ .......................... ................. .......... .......... ........... ....... 15 . 15 4.3.1.1 Low Low RRC Success Rate............... ............................. ............................ ............................ ............................ ............................ ............................. ......................... ............... ......... .... 15  15 4.3.1.2 Low Low RAB Success Rate.............. ............................ ............................ ............................ ............................ ............................ ............................. ............................. .................... ...... 15  15 4.3.2 Failure after Admission: Core Transport Network Congestion.......... .................... ..................... ..................... ........................................ .............................. 15  15 4.3.3 Failure after Admission: Hardware Usage (Channel Elements).............. ............................ ............................. ........................ ............... ............ ............ ...... 16  16 4.3.4 Failure after Admission: Channeliz Channelization ation Codes............. ........................... ............................ ............................ ............................ ............................ ...................... ............ .... 16  16 4.3.5 Failure after Admission: Others.............. ............................ ............................ ............................ ............................ ............................. ............................. .................... ............ ........... ........ ... 16  16

4.4 Accessibility issuesinnot detected by............................. counters .................. ......... .................. .................. .................. .................. ................ ........... ......... .......... .......... .......... ....... .. 17   17 4.4.1 HW HW Problems the RBS ............................. .............. ............................ ............................ ............................ ............................. ............................. ......................... ................ .....  17 17 4.4.2 4.4.3 4.4.4 4.4.5

UL Interferenc Interferencee.............. ............................ ............................. ............................. ............................ ............................ ............................ ............................ ......................... ................ .......... .......... .......... ...... 17 . 17 RACH misconfigu misconfiguration ration .............. ............................ ............................ ............................ ............................ ............................ ............................. ............................. ............................ ................... ..... 17  17 Cell Unavailabi Unavailability lity............. ........................... ............................ ............................ ............................ ............................. ............................. ............................ ............................ ............................ ............... 17 . 17 Node Blocking ............. ........................... ............................ ............................ ............................ ............................ ............................. ............................. ............................ ............................ .................... ....... 17 . 17

5 REFERENCES................................................ ................................................................................................. ......................................................... ............... ............... ............... ....... 18 6 ANNEX I: UE Idle Mode Procedures....................................................... ......................................................................... .......................... ............... ........... .... 19 6.1 PLMN Selection and Reselection........ ................. .................. .................. .................. .................. .................. .................. .................. .................. .............. ......... ......... ........ ... 19  19 6.2 Reading System Information........ ................. .................. .................. .................. .................. .................. .................. .................. ............... ........... .......... .......... .......... .......... ...... 20  .20 6.3 Cell Selection and Reselection......... .................. .................. .................. .................. .................. .................. .................. .................. .................. .................. .............. .......... ....... .. 21  21 6.3.1 Cell Selection ............. ........................... ............................ ............................ ............................. ............................. ............................ ............................ ............................ ............................. ....................... ........ 21  21 6.3.2 Cell Reselection ............. ........................... ............................ ............................ ............................. ............................. ............................ ............................ ............................ ........................... ................... ...... 21  21 6.3.3 Location/Ro Location/Routing uting Area Update.............. ............................ ............................. ............................. ............................ ............................ ............................ ............................. ....................... ........ 22  22 6.3.4 Paging Procedure ............. ........................... ............................. ............................. ............................ ............................ ............................ ............................. ............................. ......................... ................ ..... 23  23

7 ANNEX II: Call Establishmen Establishmentt Procedure..... ........... ............ ........... ........... ........... ........... ............ ........... ........... ........... ......... ........ ....... ....... ........ ........ .... 24 7.1 Voice Call Estab Establishm lishment ent .................. ..................................... ..................................... .................................... .................................... .................................... ........................... ......... 24  24 7.2 PS Data Call Establishment Establishment ................. .................................... ..................................... .................................... ........................................................... ......................................... 24  24 7.3 Radio Resource Contr Control ol (RRC (RRC)) ................. .................................... ..................................... .................................... ..................................................... ................................... 24  24 7.3.1 RRC connectio connection n Request & Setup.............. ............................ ............................ ............................ ............................ ............................ ......................... ................ .......... .......... .......... ...... 25 . 25

7.4 Core Netwo Network rk Nego Negotiati tiation on ................. ................................... .................................... ..................................... ..................................... .................................... .......................... ........ 27  27 7.5 Radio Access Bearer (RAB) Setup and Reconfiguration Reconfiguration........ ................. .................. .................. .................. ................ ............ .......... .......... ....... .. 27  27

 

1 I N T R D UC UC TI TI N This series of Optimization Guidelines covers all the main topics regarding

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Performance Monitoring & Analysis Configuration settings Troubleshooting Refer to the internal Claro document “Optimization Process” (DEO.OTM.IOP3000), for a summary of 3G WCDMA Radio  Access Network Optimization Basics. This specific document focuses on ACCESSIBILITY and its specifics within ERICSS N  infrastructure (Release P7.1). Target users for this document are all personnel requiring a detailed description of this process (Accessibility Optimization), as well as configuration managers who require details to control the functions and optimize parameter settings. It is assumed that users of this document have a working knowledge of 3G telecommunications and are familiar with WCDMA.

Document Revision Control R ev i s io n Draft 01

D at e 13-Nov-2009

A u t ho r QCES/Ericsson

C h ang e s First Release of the document Update from P7 to P7.1: NAS signalling phase counters added, both to CSSR KPIs and Medium Level KPIs

•

Corrections/Additions::

01

12-Mar-2010

QCES/Ericsson

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pmNoLoadSharingRrcConnCs/Ps pmNoLoadSharingRrcConnC s/Ps added to CSSR KPIs Iu Signalling connection phase added to CSSR KPIs CS and PS CSSR now correctly expressed in terms of SUM of all CS / PS RAB types  Additional formulas formulas for GoS metrics New sections added in Annex for Core Negotiation and RAB Setup and Reconfiguration phases

 

2 ACCE ACCESS SSIB IBIL ILIT ITY Y  Accessibility is the ability of a service to be obtained within specific tolerances and other given conditions, when requested by the user. In other words, the ability of a user to obtain the requested service from the system.

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Target is to get a 100% Accessibility, i.e., all users always get the service they request. Poor Accessibility is typically due to some form of congestion (before or after Admission Control?) hardware/software fault (Check ALARMS, Cells Downtime, tickets in REMEDY…)

misconfiguration (AUDIT the settings in RNC) other reasons (for instance, it is also possible that there is some external source of interference (such as a microwave link on the same frequency) affecting the accessibility)

•

 Accessibility is to be monitored independently independently for the different RAB types (e.g. Speech, CS Video, PS Interactive R99, PS Interactive HSDPA, etc.) as in certain situations only one of the RAB types will be affected.

2 .1 .1 I d lle e M od ode  Accessibility issues may occur related related to the UE idle mode behavior.

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The UE in Idle mode performs next 5 main tasks [Refer to ANNEX to  ANNEX I for I for a brief review]: PLMN selection and reselection

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Reading system information (MIB, SIB)

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Cell selection and reselection Location area (LA) and routing area (RA) registration/update Paging procedure Settings should guarantee that the UE in idle mode is always in the best conditions to access the network (i.e., to initiate a Mobile Originated call, MO) and be reached by the network (i.e., to receive a Mobile Terminated call, MT).

2.2 Call Call Est Establ ablish ishmen mentt Proces Processs Each step in the Call Establishment process should be monitored in order to clearly identify where the accessibility issue is located. For a more complete review of the Call Establishment Process, refer to ANNEX to  ANNEX II. II.

 

3 ACCESSI ACCESSIBILI BILITY TY KPIs (Key (Key Performan Performance ce Indicato Indicators) rs) Below the main metrics used for Accessibility Monitoring of a 3G WCDMA/UMTS Network, and their implementation with Ericsson  counters.

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Refer to “SMART Documentation” for further details on the actual implementation of these KPIs in the tool, together with the additional considerations regarding: Treatment of zeros in the denominators Cell Reselection during RRC Establishment Phase RRC Redirections (Load Sharing feature) RRC Repetitions Incoming HHO and SRNS Relocations RAB Load Sharing features (Inter-frequency and Directed Retry to gsm)

3.1 High High Le Leve vell KP KPIs Is

3.1.1 3.1 .1

Cal Calll Set Setup up Su Succe ccess ss Rate Rate - CSS CSSR R (% (%))

This is the first “overall” metric we are considering to monitor Accessibility as a whole. Up to P7.1, this KPI was typically calculated by considering just 2 steps in Call Establishment: RRC Connection Setup and RAB Establishment. They are assumed to be independent processes, and therefore CSSR was hence calculated as product of the Success Rates of each of these 2 phases (described later in section 3.2): 3.2): CS/PS_CSSR = 100 * CS/PS_RRC_SSR CS/PS_RRC_SSR   * CS/PS_RAB_ESR

where: CS/PS_RRC_SSR = RRC Setup Success Rate  (with CS/PS Establishment Causes) = ( # CS/PS RRC Connection Setup Complete / # CS/PS RRC Connection Request) CS/PS_RAB_ESR  CS/PS_RAB_ESR  = RAB Establishment Success Rate (for CS/PS RABs, both R99 and HS) = ( # CS/PS RAB Assignment Complete / # CS/PS RAB Assignment Request)   3.1. 3.1.1. 1.1 1 CS CS CSSR SR (%) (%) (For CS connection requests)

   ∑ pmNoRabEstablishAttempt(RAB)] - pmNoDirRetryAtt   (pmTotNoRrcConnectReqCs - pmNoLoadSharingRrcConnCs)  [(RAB) 

 100 * 

pmTotNoRrcConnectReqCsSucc 

 *

∑ pmNoRabEstablishSuccess(RAB)

(RAB)

where (RAB) = Speech, Cs64, Cs57 Low value (e.g.