1. 1 © 2007 Nokia Masters Thesis Seminar.ppt / 2007-03-07 / CK Automated testing of congestion within the UMTS cellular network Masters’ Thesis Seminar Claes Kaarni Prof Riku Jäntti 7.3.2007 Tietoliikennelaboratorion neuvotteluhuone SE208b

2. 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

3. 3 © 2007 Nokia Masters Thesis Seminar.ppt / 2007-03-07 / CKa 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?

4. 4 © 2007 Nokia Masters Thesis Seminar.ppt / 2007-03-07 / CKa 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

5. 5 © 2007 Nokia Masters Thesis Seminar.ppt / 2007-03-07 / CKa Network architecture – Release 99

6. 6 © 2007 Nokia Masters Thesis Seminar.ppt / 2007-03-07 / CKa 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

7. 7 © 2007 Nokia Masters Thesis Seminar.ppt / 2007-03-07 / CKa 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

8. 8 © 2007 Nokia Masters Thesis Seminar.ppt / 2007-03-07 / CKa What was done2/2 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

9. 9 © 2007 Nokia Masters Thesis Seminar.ppt / 2007-03-07 / CKa 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

10. 10 © 2007 Nokia Masters Thesis Seminar.ppt / 2007-03-07 / CKa 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. 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