UMTS Performance Trouble Shooting and Optimization Guidelines Ericsson Accessibility

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UMTS RAN Performance

Trouble Shooting Guidelines –

Ericsson UMTS Accessibility

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Introduction

Purpose & Scope

The intent of this document is to provide UMTS Trouble Shooting and Optimization from KPI and Counter perspectives for Ericsson (E///) Accessibility and provide detailed analysis strategies for identifying reason for the KPI trends and offering guidelines for improving performance by Key Optimization techniques.

The KPI/Counters described here are applicable to the P6 release of Ericsson UTRAN.

This document is not all inclusive and is only intended to provide a quick cook book to understand available E/// for trouble shooting and optimization best practices Guideline Document. For any information not covered here, Ericsson product documentation (CPI/ALEX Libraries) should be referenced.

Definitions for this Document

Term or

Acronym Definition

3GPP Third Generation Partnership Project

AS Active Set

BSIC Base Station Identity Code BTS Base Transceiver Station

CN Core Network

CPICH Common Pilot Channel DCH Dedicated Channel

DL Downlink

DPCCH Dedicated Physical Control Channel DPCH Dedicated Physical Channel

DRNC Drift Radio Network Controller FACH Forward Access Channel FIFO First In First Out

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Term or

GSM Global CommunicationsSystem for Mobile HCS Hierarchical Cell Structure

HSDPA High Speed Data Packet Access IAF Intra Frequency

IE Information Element IEF Inter Frequency

IFHO Inter Frequency Handover Inter-RAT Inter Radio Access Technology IRAT Inter Radio Access Technology Iur Interface between two RNC’s KPI Key Parameter Indicator

LA Location Area

LAI Location Area Indicator NBAP Node B Application Part Node B

Logical node responsible for radio transmission and reception in one or several cells

OCNS Orthogonal Channel Noise Simulator PLMN Public Land Mobile Network

RA Routing Area

RAB Radio Access Bearer RAI Routing Area Indicator RAN Radio Access Network RAT Radio Access Technology

RB Radio Bearer

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Term or

RF Radio Frequency

RL Radio Link

RNC Radio Network Controller RRC Radio Resource Control RSCP Received Signal Code Power RSSI Received Signal Strength Indicator SIB System Information Block

SIR Signal to Interference Ratio

TRX Transceiver

TX Transmit

UE User Equipment

UL Uplink

UMTS Universal Mobile Telecommunication Services UTRAN UMTS Terrestrial Radio Access Network WCDMA Wideband Code Division Multiple Access

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Accessibility

Accessibility is defined as the ability of a user to access the UMTS network

successfully to utilize the available services. The metrics within Ericsson RNC and OSS provide counters and KPI’s that describe the behaviors and experience of the

subscribers while accessing the UMTS network.

This is divided up into a number of areas, CS and PS, as well as being divided on an RRC and RAB basis.

The services which have counters for Accessibility are:

• CS Voice

• CS Data

• SRB

• Video

• PS Streaming & Interactive

• HSDPA Streaming & Interactive

• EUL (HSUPA)

In the following sections, CS Voice, PS Interactive and HSDPA will be discussed in detail.

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Troubleshooting Flowchart

The following flowchart may be useful for troubleshooting accessibility issues based on the problem areas

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Flow chart in PowerPoint

Microsoft Office

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Voice Access Failure Rate

The metrics measures user ability to access the mobile network for circuit switched voice calls. The metrics consists of two components of CS Access call, RRC and RAB. RRC part of the equation measures Conversational (originating and terminating) and Emergency calls. The RAB part of the equation measures Speech RAB and is pegged on the best cell in the active set in Serving RNC. The RRC measures Conversational Voice and Data (CSV+CSD) while RAB part measures only Speech for both originating and terminating causes. The non-access stratum (signaling) part of the access call flow is not included in this KPI.

KPI’s Formula & stats availability: KPI’s are based on following formulae.

Voice Access Failures = Voice RRC Failures + Voice RAB failures

Voice Access Failure Rate (%) = 100 *

(

1 – (Voice RRC Failure Rate* Voice RAB Failure Rate)

)

Voice Access failures Breakdown

These metrics can be used to determine the breakdown of access failures on an RNC, Market or Region level and can be shown as following to identify the distribution of RRC / RAB failures to total Voice access failures.

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This chart helps us to analyze issues impacting Voice accessibility showing the breakdown between RRC & RAB failures and accordingly troubleshoot the prominent failures with help of corresponding counters listed for RRC & RAB failures.

CS Voice RRC Accessibility

The counters for CS Voice RRC Accessibility are extensively available for the UMTS Services in Ericsson OSS; however RRC access failures formula is based on two counters. These metrics can be run on Cell /RNC/Market/Region level.

This is made up of the following counters:

Counter Description Condition MO Class

pmTotNoRrcConnectReqCs (CS RRC connection requests) Total number of Conversation al Call (originating and terminating) and Emergency Call RRC Connection attempts

The counter is increased when the RRC Connection Request message

is received with Establishment Cause ’Originating

Conversational Call’ or ’Terminating Conversational Call’.

Note: This counter does not count repeated RRC connection requests. UtranCell pmTotNoRrcConnectReqCsS ucc (CS RRC connection successes) Total number of Successful Conversation al Call (originating and terminating) and Emergency Call RRC Connection attempt

The counter is increased when an RRC Connection Setup Complete message is received following an attempt to setup an originating or terminating conversational call.

UtranCell

This KPI shows the percentage of RRC access failures by the total number of RRC attempts. Following formula is used for these KPI:

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To understand clearly the causes for CS RRC access failures, we would divide it in two main categories:

a)

CS RRC Setup Failures:

These failures are mainly associated with RRC rejections due to MP load, Node-B / Transport network congestion or configuration errors, Cell Congestion (Admission Control) and insufficient licensed capacity. b)

CS RRC Access (Radio reasons) Failures

:

These failures are mainly due to

radio reasons. By subtracting RRC setup failures from Total RRC access failures, we can get the numbers for RRC access failures due to radio reasons.

In Ericsson RNC, counters are available to breakdown RRC Setup failures to aid troubleshooting of such access issues. These single counter based KPIs are available in the same Accessibility report.

CS RRC Setup Failures Counters:

(Pegged for CS calls only)

Counter Description Condition MO

Class pmNoRrcConnReqBlockTnCs (CS RRC fails - TN Congestion/Blocking) # RRC Connection Setup attempts for Circuit Switched calls that fail due to Transport Network blocking.

This counters is stepped if the establishment of an RRC Connection Request with Establishment Cause = Originating/Terminating

Conversational or Emergency, fails due to congestion on the user plane (AAL2) or control plane (UniSaal or SCTP) of the transport network as a result of user dimensioned

transport network resource shortages. UtranC ell pmNoRrcConnReqBlockNode Cs (CS RRC Fails - NodeB Blocking) # RRC Connection Setup attempts for Circuit Switched calls that fail due to node blocking.

This counter is stepped if the establishment of an RRC Connection Request - with Establishment Cause equal to Originating/Terminating

Conversational or Emergency - fails due to node configuration error, node limitations or transport

network layer service unavailability.

UtranC ell pmNoRrcCsReqDeniedAdm (CS RRC rejects due to Admission control) # CS calls denied by admission control.

Counter is triggered when an RRC CONNECTION REQUEST with the cause; “Originating Conversational Call”, “Terminating Conversational Call”, or “Emergency call” is denied by Admission Control. UtranC ell pmNoFailedRrcConnectReqC sHw (CS RRC denied - Insufficient Licensed Capacity) # CS calls denied by admission control due to insufficient licensed capacity in

Incremented by one when an RRC connection request with cause Originating Conversational Call, Terminating Conversational call, or emergency call is denied by

admission control due to

insufficient licensed capacity in the

UtranC ell

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Counter Description Condition MO Class the RBS. RBS.

RRC Setup Failures Counters:

(Pegged for CS & PS calls together)

Class pmNoRejRrcConnMpLoadC (RRC reject due to MP load control) # of rejected RRC connections due to module MP load control (includes incoming Inter-RAT CC)

Sending of the RRC message RRC connection Reject with rejection cause congestion when the congestion cause has been indicated by internal load control.

Please Note This counter

is pegged for CS & PS

services.

UtranC ell

Above mentioned counters can be used to determine the access failures caused by Setup issues in the cell. These counters can also be used in conjunction with the Total RRC failures for the trend analysis on the RNC/Market or Region level.

Subtracting their value from total RRC failures can give us the Voice RRC access failures due to radio reasons –

Radio Reasons CS RRC access failures = (Total CS RRC access failures)–(CS RRC Setup failures)

A special attention must be paid for using (RRC reject due to MP load control) counter as this is pegged for both CS & PS calls, so contribution from CS & PS RRC access failures to this counter value must be decided based on CS & PS total RRC failures.

There are two additional counters available also which are pegged for both CS + PS calls and Setup + Radio access failures together. So, these counters can be used more for information & trending instead of troubleshooting.

RRC Failures Counters:

(Pegged for CS + PS calls and Setup + Radio

Access failures together)

Class pmTotNoUtranRejRrcConnRe q (Total RRC rejects by UTRAN) Total number of UTRAN rejected RRC Connection

When an RRC Connection Request is received and no internal UE identity

is available in the RNC, or MP load

UtranC ell

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Counter Description Condition MO Class Requests control function, or Admission

Control

function does not grant permission to proceed, or any internal

parameter

retrieving or calculations fail, or a DL channelization code fails to be allocated,

A connection fails to be setup to the RBS, this counter is increased. Note: This counter is never stepped if there is inter-frequency loadsharing. pmNoFailedAfterAdm (RRC+RAB) Failures after Admission Control

(Please note this

counter also counts

RAB failures)

# RRC or RAB establishmen t requests failed after being admitted by admission control.

The counter is increased if a function that has been granted admission for

a UE fails after being admitted due to a problem in the RRC or RAB Setup

procedure. Then the admission control function must be informed about the

release of previously requested resources due to the failed procedure and this counter is increased. The counter is increased in the cell or cells where the UE is located. This counter is stepped for all cells if UE is in macrodiversity.

Note: The counter is not stepped for D-RNC cells or at failure of repeated RRC connection requests.

UtranC ell

RNC/Market/Region Level Reporting

This section covers analysis of Accessibility % for Ericsson and identification of issues using the available Ericsson accessibility counters.

CS RRC Access failures Breakdown

These metrics can be used to determine the breakdown of drops on an RNC, Market or Region level and can be shown as following.

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0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

1/1/2009 1/2/2009 1/3/2009 1/4/2009 1/5/2009 1/6/2009 1/7/2009 1/8/2009 1/9/2009 1/10/2009 1/11/2009 1/12/2009 1/13/2009 1/14/2009 1/15/2009 1/16/2009 1/17/2009 1/18/2009 1/19/2009 1/20/2009 1/21/2009 1/22/2009 1/23/2009 1/24/2009 1/25/2009 1/26/2009 1/27/2009 1/28/2009 1/29/2009 1/30/2009 1/31/2009 2/1/2009 2/2/2009 2/3/2009 2/4/2009 2/5/2009 2/6/2009 2/7/2009 2/8/2009 2/9/2009 2/10/2009 2/11/2009

Voice RRC Failures Distribution

CS RRC Failures_Radio Access CS RRC Failures_Setup

Figure : CS RRC’s accessibility mostly influenced by Radio Access Failures, however on certain days, RRC setup failures have also increased significantly to 60%, for example on 1/1/2009)

In the next chart, we would break up the causes for these setup failures to identify the prominent cause for such failures:

Figure : “RRC rejects due to MP Load” is the main cause for CS RRC setup failures increasing as high as 100% on certain days.

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Although this chart provides an overview of Setup issues impacting CS RRC accessibility, yet the highlighting point of this chart is CS RRC failures due to - NodeB Blocking (failures due to node configuration error, node limitations or transport network layer service unavailability) which increased up to 95+% on 1/31/2009. This is where optimizers must focus their attention also to ensure Node-B’s configuration is appropriate to meet traffic demand.

Since the counter for “RRC rejects due to MP Load” is stepped up for all network access causes (CS call, PS call, SMS, Location update), hence appropriate estimation should be made during analysis to count CS RRC failures due to this reason. This has been done in to plot the values for RRC reject due to Mp load (CS calls) in graphs for figure 3 & 4.

Following methodology was used

i) Ratio (%) for CS RRC attempts to total RRC attempts was calculated.

ii) Same ratio was then applied to “RRC rejects due to MP Load” counter value to calculate the value for RRC reject due to Mp load (CS calls) used in this graph.

Plotting the same causes in Bar format graph to show number of failures per reason.

Figure “RRC rejects due to MP Load” is the main cause for RRC setup failures increasing as high as 100% on certain days.

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Cell Analysis

CS RRC Setup Phase Failure Causes

a) CS RRC rejects due to Admission control

This counter is pegged when the RNC decides to reject the RRC connection request because of the Admission control on the cell.

This admission control can be initiated generally due to lack of downlink power or lack of downlink channelization codes as seen in the Northeast network until now since commercial launch. Problem can be due to uplink causes also but downlink ideally gets congested before uplink.

However, before concluding this admission control has been triggered due to increased traffic in the cell, please verify following 3 main points:

i) OCNS is deactivated on the cell.

ii) Feeder length attenuation & TMA parameters are set correctly as per CIQ. iii) Admission control parameters (Power Adm, power offset, dlcodeAdm…) are

consistent to Baseline values.

b) CS RRC Fails - NodeB Blocking

This counter is stepped up fails due to node configuration error, node limitations or transport network layer service unavailability. So, please check Transport network availability (T1 related issues which can be checked from T1 error counters) to identify the main cause for these failures.

c)

CS RRC Fails – Transport Network Blocking

This counter is stepped up fails due to congestion on the user plane (AAL2) or control plane (UniSaal or SCTP) of the transport network as a result of user dimensioned transport network resource shortages. So, please verify IuB link AAl2 path (ATM cells) configuration to identify the main cause for these failures.

d)

CS RRC denied - Insufficient Licensed Capacity

This counter value is stepped due to potential hardware, configuration or resource issue in the Node-B.

Resource congestions can be verified from the Channel Element usage counters. If traffic is low and CE usage is high, it may be due to hanging resources. However, If traffic is high, it might be due to shortage of license keys for CE. (Compare the max CE used counters with installed license keys in the Node-B).

Also check the number of users in Compressed Mode. Current parameter settings allow maximum 16 users in Compressed Mode. If the number of users in compressed

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mode is high when there is no traffic in the cell it is also indicates that there is hanging resources in the cell.

A site reset normally corrects these problems, if the problem does not clear or repeats a ticket should be open with the field technicians to investigate. Potential issues on the site that can cause this problem can be:

• Incorrect configuration data (audit the commissioning file for any discrepancies) • Corrupt files in the NodeB (Recommissioning should resolve this problem)

• Corrupt software in the NodeB (Software upgrade/ downgrade can be used to reload the software in the site)

• Faulty hardware (System module).

e)

RRC rejects due to High MP Load

This counter value is generally stepped whenever the issue is RNC wide or multiple sites connected to Main / Extension sub-Rack of RNC. It is unlikely that this will step up for a cell specific issue.

So, please check for Core network (MSS/SGSN) outages if this counter value is exceptionally high on any given day. MP load counters are available from Capacity 1 report to correlate these rejections with high load.

For the regularly reported values of this counter, please check sites configuration on Main & Extension sub-racks of the RNC. As this may require, rehoming of sites from one rack to another or addition of new Extension Sub-rack to decrease MP load on all sub-racks.

0.0.0.1. CS RRC Radio Access Phase Failure Causes

a)

CS RRC Connections Access Failure due to Radio Reasons

These failures are mostly RF related and can be split between:

• Bad Coverage (Low RSCP)

• Interference (Low Ec/No)

Route cause analysis will in most cases require WMRR/drive test analysis.

Also verify that the uplink RTWP value for these sites is within acceptable range to isolate the problem due to uplink issues.

b)

CS RRC Connections Access Failure due to UE Failures

The cause for this counter can be coverage even though L1 synchronization has been achieved it can still be that a sudden loss in coverage was experienced. If only one site is showing a high count for this counter the most likely cause is that it is coverage related. If this is an RNC wide problem it needs to be determine if it

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is a specific Ue type that is causing the problem, this will require advance analysis with the help of K18 and potentially the Xmine team.

Also verify that the uplink RTWP value for these sites is within acceptable range to isolate the problem due to uplink issues.

c)

CS RRC Connections Access Failure due to RNC Failures

If the counter is showing a step change it might be related to a new software load that was loaded on the RNC or core network side. To trouble shoot these problem it will require in-depth analysis on the RNC which should be done by Tier 2. If only particular sites are showing a high count for this counter investigate if there is any common point of failure for these cells ( Same RNC, same Transmission path/ hardware) Also investigate if the T1 for these sites are error free (Look at the cell availability and BER for T1)

Worst Cells Analysis

All of the mentioned metrics are pegged on Cell level. The Worst Offenders in an RNC/Market/Region level should be ranked by the following metrics:

• CS RRC access failures

• CS Radio Reasons RRC access failures

• CS RRC access failures due to Admission control

• CS RRC access fails –Node B/ TN Congestion

CS Voice RAB Accessibility

The metrics for CS Voice RAB Accessibility are extensively available also and similar to RRC accessibility, CS .KPIs are based on following two counters:

pmNoRabEstablishAttemptS peech (CS Voice RAB connection requests) Number of RAB establishmen ts attempts (Speech) referred to the Best Cell in the Active Set.

The counter is incremented after successful RAB Mapping when when a

RANAP RAB Assignment Request message is received from the CN with RABs to be setup or modified. The counters shall be reported per single RAB state on Best Cell level for each RAB that is established

Note: This counter is only incremented in the SRNC.

UtranCell

pmNoRabEstablishSuccessS peech (CS Voice RAB connection success) Number of successful RAB establishmen ts (Speech)

This counter is incremented after successful RAB

Establishment (on DCH or common channel) before sending the RANAP RAB

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referred to the Best Cell in the Active Set.

Assignment Response message to the CN.

Formula:

Following formulas are used for these KPIs:

Similar to CS RRC access failures breakdown, CS RAB access failures are also broken down in two main categories:

c)

CS RAB Setup Failures:

These failures are mainly associated with RRC rejections due to MP load, Node-B / Transport network congestion or configuration errors, Cell Congestion (Admission Control), Lack of hardware resources, lack of ASE and UE capability.

d)

CS RAB Access (Radio reasons) Failures

:

These failures are mainly due to radio reasons. By subtracting RRC setup failures from Total RRC access failures, we can get the numbers for RRC access failures due to radio reasons.

CS RAB Setup Failures Counters:

(Pegged for CS calls only)

pmNoOfNonHoReqDeniedSp eech (Voice RAB Failures due to Admission Control)

Number of Speech RAB establishments rejected by admission control. Note: The counter is applicable to all Speech RAB establishments including establishment on a Speech

/Interactive multi RAB configuration.

The counter is increased in the cell where admission is rejected.

Note: The counter is not stepped when admission is rejected in a D-RNC cell. UtranCell pmNoRabEstBlockTnSpeech Best (Speech RAB Block - TN Congestion/Failure (Best Cell) Number of RAB establishment attempts for RAB-type Speech that are blocked due to TN congestion or TN failure, counted on the best cell.

This counter is stepped when the establishment of a Speech RAB fails due to UNI-SAAL or AAl2 congestion, IP

resource limitations or blocking as a result of

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Counter Description Condition MO Class user dimensioned

transport network configured capacity.

The counter is stepped for the best cell in the active set but only if the cell is in the SRNC.

pmNoRabEstBlockTnSpeech (Speech RAB Block - TN Congestion/Failure (Blocked cell)

Number of RAB

establishment attempts for RAB-type Speech that are blocked due to TN congestion or TN failure, counted on the blocking cell.

This counter is stepped when the establishment of a Speech RAB fails due to congestion on the user plane (AAL2) or control plane (UniSaal or SCTP) of the transport network as a result of user dimensioned transport network resource shortages. UtranCell pmNoRabEstBlockNodeSpee chBest (Speech RAB Block - Node

Congestion/Failure (Best Cell)

Number of RAB

establishment attempts for RAB-type CS Speech that are blocked due to node congestion or node failure, counted on the best cell.

This counter is stepped when the establishment of a CS Speech RAB fails due to node configuration error, node limitation, or transport network layer service

unavailability.

UtranCell

CS RAB Setup Failures Counters:

(Pegged for CS & PS calls)

Class PmNoFailedRabEstAttemptLackDlPwr

(RAB failures - Lack of DL power)

Number of failed RAB establishment attempts due to lack of DL power

Counter is stepped when admission control fails with reject reason lack of DL power.

UtranCel l

pmNoFailedRabEstAttemptLackDlCh nlCode (RAB failures - Lack of DL Channelization code)

Number of failed RAB establishment attempts due to lack of DL channelization codes. Number of failed RAB establishment attempts due to lack of DL channelization codes. UtranCel l

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Counter Description Condition MO Class PmNoFailedRabEstAttemptLackDlAse

(RAB failures - Lack of DL ASE)

Number of failed RAB establishment attempts due to lack of DL ASE

Counter is stepped when admission control fails with reject reason lack of DL ASE.

UtranCel l

pmNoFailedRabEstAttemptLackUlAse (RAB failures - Lack of UL ASE)

Number of failed RAB establishment attempts due to lack of UL ASE Number of failed RAB establishment attempts due to lack of UL ASE. UtranCel l pmNoFailedRabEstAttemptLackUlHw Best (RAB failures - Lack of UL hardware resources- Best cell)

Number of failed RAB establishment attempts due to lack of UL hardware resources, for the best cell in the active set.

The counter is stepped for the IubLink containing the best cell in the active set.

UtranCel l

pmNoFailedRabEstAttemptLackDlHw Best (RAB failures - Lack of DL hardware resources- Best cell)

Number of failed RAB establishment attempts due to lack of DL hardware resources, for the best cell in the active set.

UtranCel l

pmNoFailedRabEstAttemptLackUlHw (RAB failures - Lack of UL hardware resources)

Number of failed RAB establishment attempts due to lack of UL hardware resources.

The counter is stepped for the IubLink containing the first cell to fail admission in the active set

UtranCel l

pmNoRabEstablishFailureUeCapabilit y (RAB failures due to UE Capability) Number of failed RAB establishments due to insufficient UE capabilities When the Ue Capability check fails for the state to which it is established, the counter is incremented. UtranCel l

Above mentioned counters can be used to determine the access failures caused by Setup issues in the cell. These counters can also be used in conjunction with the Total CS RAB failures for the trend analysis on the RNC/Market or Region level.

Subtracting their value from total RRC failures can give us the CS RAB access failures due to radio reasons –

Radio Reasons CS RAB access failures = (Total CS RAB access failures)–(CS RAB Setup failures)

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A special attention must be paid for using counters pegged for both CS & PS calls. Contribution from CS & PS RAB access failures to this counter value must be decided based on ratio of CS & PS total RAB failures.

There 1 more counter available also which are pegged for both CS + PS calls and Setup + Radio access failures together. So, this counter can be used more for information & trending instead of troubleshooting. (already mentioned in CS RRC access failure part of this report)

RAB Failures Counter:

(Pegged for CS + PS calls and Setup + Radio

Access failures together)

Class pmNoFailedAfterAdm

(RRC+RAB) Failures after Admission Control

(Please note this

counter also counts

RAB failures)

release of previously requested resources due to the failed procedure and this

counter is increased. The

counter is increased in the cell or cells where the UE is located. This counter is stepped for all cells if UE is in

macrodiversity.

UtranC ell

CS RAB Access failures Breakdown

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0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

1/1/2009 1/2/2009 1/3/2009 1/4/2009 1/5/2009 1/6/2009 1/7/2009 1/8/2009 1/9/2009 1/10/2009 1/11/2009 1/12/2009 1/13/2009 1/14/2009 1/15/2009 1/16/2009 1/17/2009 1/18/2009 1/19/2009 1/20/2009 1/21/2009 1/22/2009 1/23/2009 1/24/2009 1/25/2009 1/26/2009 1/27/2009 1/28/2009 1/29/2009 1/30/2009 1/31/2009 2/1/2009 2/2/2009 2/3/2009 2/4/2009 2/5/2009 2/6/2009 2/7/2009 2/8/2009 2/9/2009 2/10/2009 2/11/2009

Voice RAB Access Failures

Voice RAB Radio Access Failures Voice RAB Setup Failures

Figure : New Jersey RAB’s accessibility mostly influenced by Radio Access Failures. Everyday ~90% of the failures are reported due to Radio Reasons.

In the next chart, we would break up the causes for these setup failures to identify the prominent cause for such setup failures:

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

1/1/2009 1/2/2009 1/3/2009 1/4/2009 1/5/2009 1/6/2009 1/7/2009 1/8/2009 1/9/2009 1/10/2009 1/11/2009 1/12/2009 1/13/2009 1/14/2009 1/15/2009 1/16/2009 1/17/2009 1/18/2009 1/19/2009 1/20/2009 1/21/2009 1/22/2009 1/23/2009 1/24/2009 1/25/2009 1/26/2009 1/27/2009 1/28/2009 1/29/2009 1/30/2009 1/31/2009 2/1/2009 2/2/2009 2/3/2009 2/4/2009 2/5/2009 2/6/2009 2/7/2009 2/8/2009 2/9/2009 2/10/2009 2/11/2009

Voice RAB Setup Failures Distribution

CS RAB Block -Node Congestion/Failure(Best Cell) CS RAB Failures_Adm Control

CS RAB Block -TN Congestion/Failure(Blocked cell) CS RAB Block -TN Congestion/Failure(Best Cell)

Figure 6: “CS RAB failures due to – Node Congestion” is the main cause for CS RAB setup failures.

Although Figure 6 chart provides an overview of setup issues impacting CS RAB accessibility, yet the highlighting point of this chart is CS RAB failures due to Admission Control which has increased from 2/1/2009 . This site has high traffic but

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verifying the parameter settings before concluding these rejects are caused due to increased traffic.

0 200 400 600 800 1,000 1,200 1,400

1/1/2009 1/2/2009 1/3/2009 1/4/2009 1/5/2009 1/6/2009 1/7/2009 1/8/2009 1/9/2009 1/10/2009 1/11/2009 1/12/2009 1/13/2009 1/14/2009 1/15/2009 1/16/2009 1/17/2009 1/18/2009 1/19/2009 1/20/2009 1/21/2009 1/22/2009 1/23/2009 1/24/2009 1/25/2009 1/26/2009 1/27/2009 1/28/2009 1/29/2009 1/30/2009 1/31/2009 2/1/2009 2/2/2009 2/3/2009 2/4/2009 2/5/2009 2/6/2009 2/7/2009 2/8/2009 2/9/2009 2/10/2009 2/11/2009

Voice RAB Setup Failures Distribution

CS RAB Block -Node Congestion/Failure(Best Cell) CS RAB Failures_Adm Control

CS RAB Block -TN Congestion/Failure(Blocked cell) CS RAB Block -TN Congestion/Failure(Best Cell)

Figure : “CS RAB failures due to – Node Congestion” is the main cause for CS RAB setup failures.

Following flowchart also explains how Capacity management system works in E/// OSS system.

This flowchart helps us to understand Downlink/Uplink power, channelization codes, ASE, Hardware resources and UTRAN parameters are the key aspects we must look at before concluding congestion in the cell is due to increased traffic.

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The following set of system resources are relevant within the Capacity Management scope:

Per Cell:

 Downlink channelization codes

 Downlink transmitted carrier power, non-HS part and HS-required part  Air Interface Speech Equivalents (ASE) in uplink and downlink

 Uplink Received Total Wideband Power (RTWP)

 The number of radio links per DL Spreading Factor (not including the codes (spreading factor = 16) reserved for or used by HSDPA connections)

 The number of radio links per UL Spreading Factor (not including codes used by EUL)

 The number of radio links in compressed mode  The number of serving HS connections

 The number of serving EUL connections  The number of non-serving EUL connections

Per Hardware Pool:

 RBS hardware utilization in uplink (both DCH and EUL) and downlink (both DCH and MTCH)

To monitor the system resources, Capacity Management performs periodic and event based measurements and keeps track of every radio connection setup, deletion and modification in a cell.

Since the counter for RAB failures due to lack of Tx Power/channelization codes/ASE/Hardware resources are stepped up for CS & PS calls, hence appropriate estimation should be made during analysis to count CS RAB failures due to this reason.

In the next chart, counters for Downlink path has been shown for clear visibility in the graph as RAB setup failures due to admission control are only in downlink & not in uplink.

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0 500 1,000 1,500 2,000 2,500 3,000

1/1/2009 1/2/2009 1/3/2009 1/4/2009 1/5/2009 1/6/2009 1/7/2009 1/8/2009 1/9/2009 1/10/2009 1/11/2009 1/12/2009 1/13/2009 1/14/2009 1/15/2009 1/16/2009 1/17/2009 1/18/2009 1/19/2009 1/20/2009 1/21/2009 1/22/2009 1/23/2009 1/24/2009 1/25/2009 1/26/2009 1/27/2009 1/28/2009 1/29/2009 1/30/2009 1/31/2009 2/1/2009 2/2/2009 2/3/2009 2/4/2009 2/5/2009 2/6/2009 2/7/2009 2/8/2009 2/9/2009 2/10/2009 2/11/2009

RAB Setup Failures Distribution

RAB failures - Lack of DL power RAB failures - Lack of DL Channelization code RAB failures - Lack of DL ASE RAB failures - Lack of DL hardware resources

Figure : “CS RAB setup failures due to lack of Downlink Tx power” is the main cause for CS RAB setup failures.

Although this chart highlights lack Downlink Tx Power is the prominent cause triggering admission control in this market, however attention must be paid to RAB setup failures due to lack of channelization code.

In the next section, root causes for such failures have been explained.

CS RAB Setup Failure Causes

a)

CS RAB Setup Failure Due to Admission Control

Same as CS RRC admission control

b)

CS RAB Failures - NodeB Blocking (Best Cell)

Same as CS RRC NodeB Blocking

c)

CS RRC Fails – Transport Network Blocking(Best cell) / (Blocked

cell)

Same as CS RRC Transport Network Blocking

d)

CS RAB Setup Failure Due to lack of DL/UL Tx power

e)

CS RAB Failures Due to lack of DL Channelization Codes

Same as CS RRC admission control . However, along with checking Admission control parameters & OCNS activation status, channelization code (code tree) utilization trend must be checked to confirm the lack of resources.

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f)

CS RAB Failures Due to lack of DL / UL ASE

Uplink / Downlink ASE admission policy provides a way to limit excessive interference in the respective direction (UL / DL) avoiding large variations in cell breathing. Hence, whenever RAB failures are reported due to lack of ASE, high interference should be observed in that cell for the respective link asking for UMTS radio network optimization.

However, current baseline settings has disabled DL & UL ASE admission policy, hence counters for

CS RAB Failures Due to lack of DL/UL should not be

pegged.

g)

CS RAB Setup Failure Due to lack of DL/ UL Hardware Resources

Whenever the hardware utilization in uplink and downlink by means of Channel Elements (CE) usage for dedicated channels is higher than utilization thresholds (separate for UL and DL), this counter is stepped up indicating towards the need of additional hardware in RBS to support traffic demand.

Thresholds for CE usage are related to the HW cost-model of the RBS. There may be different cost models for different channels types and for different RBSs (depending on HW type used), and therefore the HW cost-model in uplink may differ.

h)

CS RAB Setup Failure Due to UE Capability

RAB Failure due to Non-supported Request. RAB setup attempt is not started due to requested parameters are not supported by the RNC. (e.g. CS data calls) It should be looked into if this is a specific device that is requesting the unsupported RAB configuration, this investigation can only be done with the help of K18 or similar advance tracing equipment.

Voice RAB Radio Access Failure Causes

a)

Voice RAB Access Failure Due to Radio Reasons

Same as CS RRC access failures due to MS

b)

Voice RAB Access Failure Due to UE failures

c) Voice RAB Access Failure Due to RNC Internal Failures

Same as CS RRC setup failures due to RNC

Worst Cells Analysis

• Voice RAB access failures

(27)

• Voice RAB access failures – Admission Control

• Voice RAB access failures –Node B/ TN Congestion

Packet Interactive Access Failure Rate

This metrics measures user ability to access the mobile network for PS (interactive) including HSDPA. The metrics consists of two components of PS Access call, RRC and RAB. The RRC part of the equation measures PS (Interactive) for both originating and terminating calls. For multiple RRC connection request only one is considered corresponding to one call. The RAB part of the equation measures PS interactive (R99 and HS) RAB and is pegged on the best cell in the active set in Serving RNC. The non-access stratum (signaling) and PDP non-access part of the non-access call flow for Streaming is not included in this KPI.

After RRC setup, PS interactive RAB type depends on service requested by the UE, resources availability and features enabled in UTRAN network, e.g. R99 interactive RAB, HSDPA interactive, R99 streaming, HSDPA streaming, EUL (HSUPA) etc.

Since R99 streaming, HSDPA streaming, EUL features are not currently activated in the network, hence we are only covering R99 interactive RAB & HSDPA interactive RAB accessibility in this document.

For easier understanding and clarity, R99 interactive access failure section has been separated from the HSDPA interactive access failure’s section in this report. Hence, PS Interactive Access failures are now classified in 3 sub sections for detailed discussion.

a) Packet Interactive RRC Access Failure Rate (common for both R99 & HSDPA) b) R99 Interactive RAB Access Failure Rate

c) HSDPA Interactive RAB Access Failure Rate KPI’s Formula & stats availability:

2 KPI’s are available in T-PIM accessibility detailed report and these KPI’s are based on following formulae.

PS Interactive Access Failures = PS Int RRC Failures + PS Int RAB failures

PS Interactive Access Failures (%) = 100 *

(

1 – (PS Int RRC Failure Rate* PS Int RAB Failure Rate)

)

(28)

PS Interactive Access failures Breakdown

These metrics can be used to determine the breakdown of access failures on an RNC, Market or Region level and can be shown as following.

Figure : “PS RRC Access Failures” are the main cause for PS Access failures.

This chart helps us to analyze issues impacting Packet Interactive accessibility showing the breakdown between RRC & RAB failures and accordingly troubleshoot the prominent failures with help of corresponding counters listed these failures. Contrary to Voice Access failures trend, PS RRC failure rate is higher PS RAB failure rate.

Cell/RBS Analysis

PS access failure metrics are pegged on Cell level. The Worst Offenders in an RNC/Market/Region level could be ranked by the following metrics:

• PS Interactive access failures

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• PS Interactive RAB access failures

Now in the next 3 sub sections, we would discuss in detail the following 3 main KPIs. a) Packet Interactive RRC Access Failure Rate (common for both R99 & HSDPA) b) R99 Interactive RAB Access Failure Rate

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PS Interactive RRC Accessibility

The KPI for PS Int RRC access failures is the PS Interactive RRC Access Failure Rate%. This KPI is cumulative for R99 Interactive + HSDPA interactive.

Following counters are directly making up these PS interactive RRC access failures:

pmTotNoRrcConnectReqPs (PS RRC connection requests) Total number of 'Originating Interactive Call', 'Terminating Interactive Call', 'Originating Background Call', 'Terminating Background Call' or 'Originating Subscribed Traffic Call', RRC connection attempts. Counter is increased when the RRC Connection Request message is received with Establishment Cause 'Originating Interactive Call', 'Terminating Interactive Call', 'Originating Background Call', 'Terminating Background Call', or 'Originating Subscribed Traffic Call'. UtranCell pmTotNoRrcConnectReqPsS ucc (PS RRC connection successes) Total number of Successful 'Originating Interactive Call', 'Terminating Interactive Call', 'Originating Background Call', 'Terminating Background Call', or 'Originating Subscribed Traffic Call' RRC connection setups. The counter is increased when an RRC Connection Setup Complete message is received following an attempt to setup Originating Interactive Call', 'Terminating Interactive Call', 'Originating Background Call', 'Terminating Background Call' or 'Originating Subscribed Traffic Call'. UtranCell

Above mentioned counters can be used in the following formulae to calculate PS RRC access failures & Failure rate (%):

To understand clearly the causes for PS RRC access failures, we would divide it in two main categories:

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a) PS RRC Setup Failures:

These failures are mainly associated with RRC rejections due to MP load, Node-B / Transport network congestion or configuration errors, Cell Congestion (Admission Control) and insufficient licensed capacity.

b)

PS RRC Access (Radio reasons) Failures

:

These failures are mainly

due to radio reasons. By subtracting RRC setup failures from Total RRC access failures, we can get the numbers for RRC access failures due to radio reasons.

PS RRC Setup Failures Counters:

(Pegged for PS calls only)

pmNoRrcConnReqBlockTnPs (PS RRC fails - TN Congestion/Blocking) Number of RRC Connection Setup attempts for Packet Switched calls that fail due to Transport Network blocking.

This counters is stepped if the establishment of an RRC Connection Request with Establishment Cause = Originating/Terminating Interactive or Background or Originating Subscribed Traffic Call, fails due to congestion on the user plane (AAL2)or control plane (UniSaal or SCTP) of the transport network as a result of user dimensioned transport network resource shortages.

UtranCell pmNoRrcConnReqBlockNode Ps (PS RRC Fails - NodeB Blocking) Number of RRC Connection Setup attempts for Packet Switched calls that fail due to node blocking.

This counter is stepped if the establishment of an RRC Connection Request - with Establishment Cause equal to Originating/Terminating Interactive, or Background or Originating Subscribed Traffic Call - fails due to node

configuration error, node limitations or transport network layer service unavailability.

UtranCell pmNoRrcPsReqDeniedAdm (PS RRC rejects due to Admission control) Number of PS calls denied by admission control.

Counter is stepped after denied admission after an RRC

CONNECTION REQUEST with any of the cause values 'Originating Interactive Call', 'Terminating Interactive Call', 'Originating Background Call', 'Originating Subscribed Traffic Call' or 'Terminating

Background Call' has been received. UtranCell pmNoFailedRrcConnectReqP sHw (PS RRC denied - Insufficient Licensed Capacity) Number of PS calls denied by admission control due to insufficient licensed capacity in the RBS.

Incremented by one when an RRC connection request with cause Originating

Conversational Call,

Terminating Conversational call, or emergency call is denied by admission control

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RRC Setup Failures Counters:

(Pegged for CS & PS calls together)

Class pmNoRejRrcConnMpLoadC (RRC reject due to MP load control) # of rejected RRC connections due to module MP load control (includes incoming Inter-RAT CC)

Sending of the RRC message RRC Connection Reject with rejection cause congestion when the congestion cause has been indicated by internal

load control.

Please Note

This counter is pegged for

CS & PS services.

UtranC ell

Above mentioned counters can be used to determine the PS RRC access failures caused by Setup issues in the cell. These counters can also be used in conjunction with the Total RRC failures for the trend analysis on the RNC/Market or Region level. Subtracting their value from total RRC failures can give us the PS RRC access failures due to radio reasons –

Radio Reasons PS RRC access failures = (Total PS RRC access failures)–(PS RRC Setup failures)

A special attention must be paid for using (RRC reject due to MP load control) counter as this is pegged for both CS & PS calls, so contribution from CS & PS RRC access failures to this counter value must be decided based on CS & PS total RRC failures.

There are two additional counters available also which are pegged for both CS + PS calls and Setup + Radio access failures together. So, these counters can be used more for information & trending instead of troubleshooting.

RRC Failures Counters:

(Pegged for CS + PS calls and Setup + Radio

Access failures together)

Class pmTotNoUtranRejRrcConnRe q (Total RRC rejects by UTRAN) Total number of UTRAN rejected RRC Connection Requests

When an RRC Connection Request is received and no internal UE identity

is available in the RNC, or MP load control function, or Admission Control

function does not grant permission to proceed, or any internal

parameter

retrieving or calculations fail, or a DL channelization code fails to be allocated,

UtranC ell

(33)

Counter Description Condition MO Class a connection fails to be setup to the

RBS, this counter is increased. Note: This counter is never stepped if there is inter-frequency loadsharing. pmNoFailedAfterAdm (RRC+RAB) Failures after Admission Control

(Please note this

counter also counts

RAB failures)

release of previously requested resources due to the failed procedure and this

counter is increased. The

counter is increased in the cell or cells where the UE is located. This counter is stepped for all cells if UE is in

macrodiversity.

UtranC ell

PS RRC Access failures Breakdown

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Figure : PS RRC’s accessibility mostly influenced by Radio Access Failures, however on certain days, RRC setup failures have also increased significantly to 60%, for example on 1/1/2009)

In the next chart, we would break up the causes for these setup failures to identify the prominent cause for such failures:

Figure : “RRC rejects due to MP Load” is the main cause for PS RRC setup failures increasing as high as 99% on certain days,

(35)

Although this chart provides an overview of Setup issues impacting CS RRC accessibility, yet the highlighting point of this chart is CS RRC failures due to - NodeB Blocking (failures due to node configuration error, node limitations or transport network layer service unavailability) which increased up to 100+% on 1/31/2009. This is where optimizers must focus their attention also to ensure Node-B’s configuration is appropriate to meet traffic demand.

Since the counter for “RRC rejects due to MP Load” is stepped up for all network access causes (CS call, PS call, SMS, Location update), hence appropriate estimation should be made during analysis to count PS RRC failures due to this reason. This has been done in to plot the values for RRC reject due to Mp load (PS calls) in graphs for figure 3 & 4. Following methodology was used

iii) Ratio (%) for PS RRC attempts to total RRC attempts was calculated.

iv) Same ratio was then applied to “RRC rejects due to MP Load” counter value to calculate the value for RRC reject due to Mp load (PS calls) used in this graph.

0 500,000 1,000,000 1,500,000 2,000,000 2,500,000 3,000,000

1/1/2009 1/2/2009 1/3/2009 1/4/2009 1/5/2009 1/6/2009 1/7/2009 1/8/2009 1/9/2009 1/10/2009 1/11/2009 1/12/2009 1/13/2009 1/14/2009 1/15/2009 1/16/2009 1/17/2009 1/18/2009 1/19/2009 1/20/2009 1/21/2009 1/22/2009 1/23/2009 1/24/2009 1/25/2009 1/26/2009 1/27/2009 1/28/2009 1/29/2009 1/30/2009 1/31/2009 2/1/2009 2/2/2009 2/3/2009 2/4/2009 2/5/2009 2/6/2009 2/7/2009 2/8/2009 2/9/2009 2/10/2009 2/11/2009

PS RRC Setup Failures Distribution

RRC reject due to MP load control (PS Calls) PS RRC rejects due to Admission control PS RRC denied - Insufficient Licensed Capacity PS RRC fails - TN Congestion/Blocking PS RRC Fails - NodeB Blocking

Figure : “RRC rejects due to MP Load” is the main cause for RRC setup failures increasing as high as 99% on certain days; e.g. 1/31/2009

(36)

Cell Analysis

PS RRC Setup Phase Failure Causes

a) PS RRC Setup Failure Due to Admission Control

b) PS RAB Failures - NodeB Blocking (Best Cell)

Same as CS RRC NodeB Blocking

d)

PS RRC Fails – Transport Network Blocking(Best cell) / (Blocked

cell)

d)

PS RRC denied - Insufficient Licensed Capacity

e)

PS RRC rejects due to High MP Load

f)

PS RRC Setup Failures Due to lack of DL/UL Tx power

g)

PS RRC Failures Due to lack of DL Channelization Codes

Same as CS RRC admission control . However, along with checking Admission control parameters & OCNS activation status, channelization code (code tree) utilization trend must be checked to confirm the lack of resources.

PS RRC Radio Access Failure Causes

a)

PS RRC Connections Access Failure due to Radio Reasons

Same as CS RRC access failures due to Radio Reasons

b) PS RRC Access Failure Due to UE Failures

c) PS RRC Access Failure Due to RNC Internal Failures

(37)

Worst Cells Analysis

• PS RRC access failures

• PS Radio Reasons RRC access failures

• PS RRC access failures due to admission control

• PS RRC access fails –Node B/ TN Congestion

R99 Interactive RAB Accessibility

In Ericsson OSS, same metrics for R99 interactive RAB Accessibility are available as for CS RAB accessibility. R99 interactive RAB accessibility is also based on two counters which are pegged on the best cell in the active set in Serving RNC. These metrics can be run on Cell/RNC/Market/Region level. The counters are as follows:

pmNoRabEstAttemptPsIntN onHs (R99 Interactive RAB connection requests) Number of RAB establishment attempts for the PS Interactive RAB in a non-HS configuration (that is on DCH or FACH). Reported on the best cell in the active set.

Incremented by one when a RANAP RAB Assignment Request message is received from the CN with RABs to be set up or modified, after successful RAB mapping to PS Interactive. The counter is reported per single RAB state for each RAB that is attempted, on the best cell in the active set, only when the last reattempt is on a non-HS configuration (that is on DCH/DCH or RACH/FACH). UtranCell PmNoRabEstSuccessPsIntN onHs (R99 Interactive RAB connection successes) Number of successful RAB establishment s for the PS Interactive RAB in a non-HS configuration (that is on DCH or FACH). Reported on the best cell in the active set.

Incremented by one after sending the RANAP RAB

Assignment Response message to the CN, indicating a

successful PS Interactive RAB establishment. The counter is reported per single RAB state for each RAB that is established, on the best cell in the active set, only if the last reattempt is on a non-HS configuration (that is on DCH/DCH or RACH/FACH).

(38)

Formula:

However, this formula is not implemented in XPM and we only get the values of PS R99 Interactive RAB access failures based on following formula and not the failure rate (%).

In Ericsson RNC, there are counters available that breakdown some of R99 interactive RAB Access failures to aid the troubleshooting of issues. All these single counter based KPI’s are available in T-PIM Accessibility detailed report.

R99 Interactive RAB Setup Failures Counters:

(Pegged for PS calls

only)

Class pmNoOfNonHoReqDeniedSpe ech (PS Interactive RAB Failures due to Admission Control) Number of Interactive RAB establishments rejected by admission control.

Note: The counter is applicable to all Interactive RAB establishments including establishment on a Speech/Interactive multi RAB configuration. Incremented by one when admission is rejected.

Note: The counter is not incremented when admission is rejected in a DRNC cell.

UtranC ell

pmNoRabEstBlkNodePsIntNo HsBest (R99 Int RAB Block - Node Congestion/Failure (Best Cell) Number of RAB establishment attempts for RAB-type PS

Interactive that are blocked due to node congestion or node failure, counted on the best cell.

This counter is stepped when the establishment of a PS Interactive RAB, excluding PS Interactive for HS, RAB fails due to node configuration error, node limitation or

transport network layer service unavailability. UtranC ell pmNoRabEstBlockTnPsIntNon Hs (R99 Int RAB Block - TN Number of RAB establishment attempts for RAB-type PS

This counter is stepped when the establishment of a PS Interactive RAB,

UtranC ell

(39)

Counter Description Condition MO Class

Congestion/Failure (Blocking cell)

Interactive that are blocked due to TN congestion or TN failure, counted on the blocking cell.

not including PS Interactive for HS, fails due to congestion on the user plane (AAL2) or control plane (UniSaal or SCTP) of the transport network layer as a result of user dimensioned transport network capacity.

pmNoRabEstBlockTnPsIntNo HsBest (R99 Int RAB Block - TN Congestion/Failure (Best Cell) Number of RAB establishment attempts for RAB-type PS

Interactive that are blocked due to TN congestion or TN failure, counted on the best cell.

Step counter when the establishment of a PS Interactive (excluding HS) RAB fails due to UNI-SAAL or AAl2 congestion, IP resource limitations or blocking as a result of user dimensioned transport network configured capacity. The counter is

stepped for the best cell in the active set but only if the cell is in the SRNC.

UtranC ell

pmNoFailedREstAttExcConnLi mit (PS RAB failures - Exceeded connection limit) Number of failed PS RAB establishment attempts due to exceeding the configured connection limit when allocating Spreading Factor ('SF Histogram' in

Admission Reject signal)

Counter is stepped when admission control fails with reject reason value SF8, SF16, or SF32.

UtranC ell

Since, there is no direct counter available for R99 Interactive RAB Failures due to Admission Control, so we can calculate it by using the following formula based on other 2 KPIs from this accessibility report (listed as # 1 & #2 in the table shown above).

R99 Int RAB Failures due to Admission Control =

(PS Int RAB Failures due to Admission Control) – (HSDPA Int RAB Failures due to Admission Control)

To calculate the values for R99 RAB failures due to radio reasons, we can use the following formula

(40)

R99 RAB access failures (Radio Reasons) =

(Total R99 RAB access failures) –(R99 RAB setup failures)

Additional counters are also available to provide insight on R99 RAB accessibility failures but these are pegged for both CS & PS RABS, hence a fair estimation is required to correlate these reasons to R99 Interactive RAB access failures.

RAB Setup Failures Counters:

(Pegged for CS & PS calls together)

Class PmNoFailedRabEstAttemptLackDl

Pwr (RAB failures - Lack of DL power)

Number of failed RAB establishment

attempts due to lack of DL power

Counter is stepped when admission control fails with reject reason lack of DL power.

UtranC ell

pmNoFailedRabEstAttemptLackDl ChnlCode

(RAB failures - Lack of DL Channelization code)

attempts due to lack of DL channelization codes.

Number of failed RAB establishment attempts due to lack of DL channelization codes.

UtranC ell

PmNoFailedRabEstAttemptLackDl Ase (RAB failures - Lack of DL ASE)

attempts due to lack of DL ASE

Counter is stepped when admission control fails with reject reason lack of DL ASE.

UtranC ell

pmNoFailedRabEstAttemptLackUl Ase (RAB failures - Lack of UL ASE)

attempts due to lack of UL ASE

Number of failed RAB establishment attempts due to lack of UL ASE.

UtranC ell pmNoFailedRabEstAttemptLackUl

HwBest (RAB failures - Lack of UL hardware resources- Best cell)

attempts due to lack of UL hardware resources, for the best cell in the active set.

UtranC ell

pmNoFailedRabEstAttemptLackDl HwBest (RAB failures - Lack of DL hardware resources- Best cell)

attempts due to lack of DL hardware resources, for the best cell in the active set.

The counter is stepped for the IubLink containing the best cell in the active set. UtranC ell pmNoFailedRabEstAttemptLackUl Hw (RAB failures - Lack of UL hardware resources)

attempts due to lack of UL hardware resources.

The counter is stepped for the IubLink containing the first cell to fail admission in the

UtranC ell

(41)

Counter Description Condition MO Class active set

pmNoRabEstablishFailureUeCapa bility (RAB failures due to UE Capability)

Number of failed RAB establishments due to insufficient UE

capabilities

When the Ue

Capability check fails for the state to which it is established, the counter is incremented. UtranC ell

RNC/Market/Region Level Reporting

These plots should be used as an indication of issues that should be investigated further on a Cell/RBS basis.

R99 RAB Access failures Breakdown

These metrics can be used to determine the breakdown of drops on an RNC, Market or Region level. However, counters reporting R99 RAB Access failures are not being reported correctly by T-PIM currently, hence graphs to show this breakdown could not be prepared.

Worst Cells Analysis

• R99 interactive RAB access failures

• R99 interactive RAB access failures – Radio Reasons

• R99 interactive RAB access failures – Admission Control

• R99 interactive RAB failures - Exceeded connection limit

(42)

HSDPA Interactive RAB Accessibility

HSDPA interactive RAB accessibility is also based on two counters which are pegged on the cell level in Serving RNC. These metrics can be run on Cell/RNC/Market/Region level. The counters are as follows:

pmNoRabEstablishAttemptPacketInter activeHs (HS Interactive RAB connection requests) The number of attempted RAB establishmen ts for PS Interactive RAB mapped on HS-DSCH. The counter is incremented after successful RAB Mapping when a RANAP RAB Assignment Request message is received from the CN with RABs to be setup or modified. The counters are

reported per single RAB state after successful HS-DSCH selection on Serving HS-DSCH cell at RAB establishment for HS.

UtranCell

pmNoRabEstablishSuccessPacketInter activeHs (HS Interactive RAB connection successes) The number of successful RAB establishmen ts for PS Interactive RAB mapped on HS-DSCH.

The counter is stepped for the selected Serving HS-DSCH cell at RAB establishment after the successfully transition SRB-DCH to PS Interactive 64/HS - HS-DSCH. UtranCell Formula:

In Ericsson RNC, counters are available to breakdown some of HS interactive RAB Access failures to aid the troubleshooting of issues. All these single counter based KPI’s are available in T-PIM Accessibility detailed report.

HSDPA Interactive RAB Setup Failures Counters:

(Pegged for HSDPA

calls only)

pmNoOfNonHoReqDeniedHs (HSDPA Interactive RAB

Number of Interactive RAB establishments

Incremented by one when admission is

(43)

Counter Description Condition MO Class Failures due to Admission Control) on a (High Speed) HS configuration rejected by admission control. rejected.

Note: The counter is not incremented when admission is rejected in a DRNC cell.

pmNoRabEstBlockNodePsInt HsBest (HS Int RAB Block - Node Congestion/Failure (Best Cell) Number of RAB establishment attempts for RAB-type PS

Interactive for HS that are blocked due to node congestion or node failure, counted on the best cell.

This counter is stepped when the establishment of a PS Interactive RAB for HS RAB fails due to node configuration error, node limitation or transport network layer service unavailability. UtranCell pmNoRabEstBlockTnPsIntHs (HS Int RAB Block - TN Congestion/Failure (Blocking cell)

Number of RAB

establishment attempts for RAB-type PS

Interactive for HS that are blocked due to TN congestion or TN failure, counted on the blocking cell.

This counter is stepped when the establishment of a PS Interactive RAB for HS, fails due to congestion on the user plane (AAL2) or control plane (UniSaal or SCTP) of the transport network layer as a result of user dimensioned transport network capacity. UtranCell pmNoRabEstBlockTnPsIntHsB est (HS Int RAB Block - TN Congestion/Failure (Best Cell)

Number of RAB

establishment attempts for RAB-type PS

Interactive for HS that are blocked due to TN congestion or TN failure, counted on the best cell.

This counter is stepped when the establishment of a PS Interactive RAB fails due to UNI-SAAL or AAl2 congestion, IP resource limitations or blocking as a result of user dimensioned transport network configured capacity. The counter is stepped for the best cell in the active set but only if the cell is in the SRNC.

UtranCell

pmNoFailedREstAttExcConnLi mit (PS RAB failures - Exceeded connection Number of failed PS RAB establishment attempts due to exceeding the Counter is stepped when admission control fails with reject reason value