Download UMTS Optimization Guideline PDF

TitleUMTS Optimization Guideline
TagsHigh Speed Packet Access Network Congestion Computer Network General Packet Radio Service Electrical Engineering
File Size1.2 MB
Total Pages84
Table of Contents
                            Basic Tuning
	KPIs and Service Requirements
		IRAT Performance
		CS Performance
			CS Requirements
		PS Performance
			PS Requirements
	Tools
		Tools Requirements
			RF Measurements
			Throughput Measurements
			Call Performance
		Tools Currently Available to Capture / Process data
			Drive Test Equipment and Software
			Post-Processing Software
	Pre-Launch Optimization Process
		Database Verification
		Drive Test Route Selection
		Drive Test Data Collection
		Data Post-processing and Root-Cause Analysis
		Root Cause Analysis and Recommendation
			High Downlink Interference
			Pilot Pollution
			Out of Pilot Coverage
			Insufficient received UL DPCH power
			High UE TX Transmit Power
			Swapped feeders
			Low data throughput
			Handover Event Detection Failure
			No Suitable Cell
		Assessing Success of Recommended Change
OMC Statistics Based Tuning
	KPIs
		IRAT - Inter Radio Access Technology (IRAT) performance
		CS Performance additional information
		PS Performance additional information
	Tools
		Tools Requirements
		Tools Currently Available to Capture / Process Data
	Post-Launch Optimization Process
		Data Post-processing and Root-Cause Analysis
		Optimization Strategy per Root-cause and/or Problem Category/Type/Area
		Assessing Success of Recommended Change
                        
Document Text Contents
Page 1

UMTS Optimization Guideline Page 1 of 84

UMTS Optimization Guideline

BASIC TUNING ............................................................................................................................................. 2

KPIS AND SERVICE REQUIREMENTS .................................................................................................................... 2
IRAT Performance .................................................................................................................................. 2
CS Performance ...................................................................................................................................... 2

CS Requirements .............................................................................................................................................. 3
PS Performance ...................................................................................................................................... 4

PS Requirements ............................................................................................................................................... 5
TOOLS ............................................................................................................................................................ 8

Tools Requirements ................................................................................................................................ 8
RF Measurements ........................................................................................................................................... 11
Throughput Measurements .............................................................................................................................. 12
Call Performance ............................................................................................................................................ 13

Tools Currently Available to Capture / Process data .......................................................................... 15
Drive Test Equipment and Software ............................................................................................................... 18
Post-Processing Software ................................................................................................................................ 22

PRE-LAUNCH OPTIMIZATION PROCESS ............................................................................................................... 24
Database Verification ........................................................................................................................... 25
Drive Test Route Selection .................................................................................................................... 27
Drive Test Data Collection ................................................................................................................... 29
Data Post-processing and Root-Cause Analysis .................................................................................. 30
Root Cause Analysis and Recommendation ......................................................................................... 31

High Downlink Interference ........................................................................................................................... 31
Pilot Pollution ................................................................................................................................................. 33
Out of Pilot Coverage ..................................................................................................................................... 34
Insufficient received UL DPCH power ........................................................................................................... 34
High UE TX Transmit Power ......................................................................................................................... 35
Swapped feeders ............................................................................................................................................. 36
Low data throughput ....................................................................................................................................... 38
Handover Event Detection Failure .................................................................................................................. 40
No Suitable Cell .............................................................................................................................................. 42

Assessing Success of Recommended Change ....................................................................................... 42

OMC STATISTICS BASED TUNING ....................................................................................................... 43

KPIS ............................................................................................................................................................ 43
IRAT - Inter Radio Access Technology (IRAT) performance .............................................................. 51
CS Performance additional information .............................................................................................. 52
PS Performance additional information ............................................................................................... 52

TOOLS .......................................................................................................................................................... 53
Tools Requirements .............................................................................................................................. 53
Tools Currently Available to Capture / Process Data .......................................................................... 54

POST-LAUNCH OPTIMIZATION PROCESS ............................................................................................................. 57
Data Post-processing and Root-Cause Analysis .................................................................................. 58
Optimization Strategy per Root-cause and/or Problem Category/Type/Area ...................................... 68
Assessing Success of Recommended Change ....................................................................................... 84

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Page 43

UMTS Optimization Guideline Page 43 of 84

Drive test and performance statistics are often used to assess success of

the recommended changes. Drive test conducted in the same problematic

area can verify whether these changes improve the performance in the

problematic area. Performance statistic in the following few days can be

used to check whether there is any side effect to other areas or other

cells.

OMC Statistics Based Tuning

KPIs

Differentiated Performance Monitoring

The QoS of differentiated packet switched (PS) and circuit switched (CS)

services can be assessed through counters collected and classified in the

RNS. The analytical approach assumes that the network topology where

the service performances are analysed is already defined (or selected

within a wider scope) together with the measurement period (history), and

user satisfaction criteria.

The identified area may encompass radio network controllers (RNC), base

stations (BSs) or Node Bs, cells and the interface between the base

station and the radio network controller (Iub). Our target is to define

essential counters and key performance indicators (KPIs) that need to be

retrieved, and/or derived from measurements in NEs, for a capacity and

QoS status view in the RNS and/or a detailed performance analysis. In the

latter case, for example, performance results may be compared directly to

the target values or, since only the QoS perceived by end-user matter,

expressed in terms of satisfied users. The network administrator may then

compare the number of satisfied users to the related target thresholds

defined a priority.

inCode CONFIDENTIAL and PROPIETARY

Page 83

UMTS Optimization Guideline Page 83 of 84

set to 9 for e1a and to 14 for e1a’. The event e1a’ inherits the settings of

event e1a except for the triggering threshold defined as follow:

Re1a’ = Re1a – Roffset, with Re1a’ ≥ 0

Description of the problem

The parameter Roffset was initially set to 0dB such that e1a and e1a’ have

the same triggering threshold.

With this original setting events e1a and e1a’ are sent at the same time

resulting in a release of the radio links in case of SHO addition failure.

Indeed, as the e1a’ is sent to release the call in case of SHO failure.

Therefore, all e1a are pre-empted by e1a’ events.

à This behaviour is suspected to create additional drops.

Implemented modification

The value of Roffset will be set to 3dB thus setting. Indeed, With the new

setting, the event e1a’ is delayed by 3dB compared to e1a which is

equivalent to extra time allowed to perform the HO. Eventually, when the

best SC of the neighbour set reaches the level of the best cell of the active

set within the range of 1dB (Re1a’) then the call is released (for CS only –

for PS there are different procedures).

Expected gains and behaviors

à Reduction of the number of e1a’ and at the same time an increase of

the number of e1a

As the e1a’ is delayed we allow more attempts of e1a and therefore this

number should increase. But we should also decrease the number of e1a’

since there will be fewer situations triggering this event. We will verify that

this delta between these two events does not increase so much that it may

overload the RNC in term of signalling.

à Lower CDR

inCode CONFIDENTIAL and PROPIETARY

Page 84

UMTS Optimization Guideline Page 84 of 84

As the system is more resistant to SHO failures there should be

improvements on the call drop rates.

Assessing Success of Recommended Change

The effect of the recommended changes should be analyzed for its

success. This can be verified through,

• Drive Test – real time throughput performance

• Statistics - KPI improvements against Baseline

• QoS Performance – from Statistics or Protocol Analyzer

inCode CONFIDENTIAL and PROPIETARY

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