1 © 2007 nokia masters thesis seminar.ppt / 2007-03-07 / ck automated testing of congestion within...

1 © 2007 Nokia Masters Thesis Seminar.ppt / 2007-03-07 / CK

Automated testing of congestion within the UMTS cellular network

Masters’ Thesis SeminarClaes Kaarni

Prof Riku Jäntti7.3.2007 Tietoliikennelaboratorion neuvotteluhuone SE208b

2 © 2007 Nokia Masters Thesis Seminar.ppt / 2007-03-07 / CKa

Agenda

•Introduction

•Current Situation

•Network architecture

•Congestion Areas

•What was done?

•Conclusions

•Next Steps


Introduction

• As the amount of 3G subscribers grow, grows the need for more accurate network dimensioning and more efficient congestion control in UMTS cellular networks

→ congested situations will be unavoidable in dense population areas

• operators want to optimize their network dimensioning to minimize costs

→ effective congestion control functions and mechanisms

→ direct savings for the operators

• Verification of congestion control functions and mechanisms is demanding

• Can implementation of this be tested with automation?


Current Situation

• We have an automated system capable of many network scenarios

• Automated system capable of repetitive test case execution

• The automation tool has several interfaces with several elements acting in a testing environment

• Interface with testing UE

• Interface with the RNC

• Interface with attenuator system

• Interface with a Load Generator

• The focus of the thesis was to study what is needed for testing congestion control with this tool


Network architecture – Release 99


Congestion Areas within the scope of the thesis• Code Tree congestion

• Shortage of spreading codes in the Code Tree

• BTS HW congestion• Shortage of BTS internal processing resources

• Iub transmission capacity congestion• Shortage of transmission capacity between BTS and RNC

• Air interface congestion• Shortage of interference capacity in the air interface


What was done? 1/2

• In the thesis it was studied what is needed for testing congestion control with the automation tool in particular

• The work was carried out by studying two congestion control features• One for real-time traffic management

• One for non-real-time traffic management

• The main principle of the congestion control features:• Downgrading or releasing NRT users

• Releasing lower priority RT users


What was done 2/2

• The testing was concluded possible in a following manner:• The automation tool verifies test case wanted to be executed

• The automation tool might perform precondition changes into the test environment

• A specific load is created into a cell with the load generator

• The automation tool starts to penetrate defined connections into the congested network

• After execution logs are collected and analyzed


Conclusions

• Testing of congestion control possible with the automation tool• Testing possible to some extent but not at same detail as in manual testing

• Testing of congestion control of real-time traffic was possible on a high level of detail

• Real-time services have stringent requirements → Simple and clear procedures

• Testing of congestion control of non-real-time traffic was possible but is considered as more demanding

• Scheduling flexible

• A big challenge to verify that correct connection is chosen as candidate for making room for the higher priority connection wanted to be established


Next Steps

• The work was focused on stationary mobile scenarios Mobility issues a great area of interest

Soft and softer handovers Inter-RNC handovers, Inter-frequency handovers, Inter-system handover

• The work relies on searching for errors from user-perspective and network internal signaling

Monitoring of network counters should be developed as a new dimension for testing

11 © 2007 Nokia Masters Thesis Seminar.ppt / 2007-03-07 / CK

Thank you !

References:

Review of RNC Interfaces and Architecture, by Mikko Nieminen, training material, 2006

Internal document about automation system, 2006

1 © 2007 nokia masters thesis seminar.ppt / 2007-03-07 / ck automated testing of congestion within...

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