Agere Systems - Optimay GmbHMay, 2003

1
UMTS terminal testing A practical perspective

• Olaf Bergengruen
• May, 2003

2
We will not survive without a proper regression
test system, an Optimay engineer
3
Overview

• Virtual testing
• Logical view (what we want to test)
• Why virtual testing
• Requirements to the test system
• 3GPP approach
• Test model
• Test cases
• Optimays implementation
• GSM/GPRS virtual test system
• GSM/GPRS/UMTS virtual test system

4
Test environment / logical view(conformance
testing, FTA)
5
Test environment / logical view (2)
6
Why virtual test environment

• We need a SW only environment (no specific HW)
• HW is expensive or does not exist
• HW debugging is difficult and time consuming
• SW developers dont want to be bothered with HW
  issues or dont have the specific skills
• We need to be much faster than real time
• Developers want to use standard tools (compilers,
  editors, debuggers)

7
Requirements to the virtual test system

• Test system shall be much faster than real time
• Support the design of test scenarios at a high
  level of abstraction
• All test suites need to run over night
  GSM/GPRS tests (GSM 11.10), UMTS test (3GPP
  34.123), STK tests (GSM 11.10-4), MMI test cases
  and possibly other suites (TCP/IP, WAP, ...)
• Test system shall be available to anybody, at
  anytime, on any PC

8
GSM/GPRS test architecture
9
GSM/GPRS test architecture
10
Great approach L1 simulated interface

• Basic communication with the Tester via three
  functions RxRadioBlock, TxRadioBlock, TimerTick
• These functions can be extended as needed to
  simulate DSP code or other HW related
  functionality
• MS is the master of system ticks, about 100
  times faster than real time
• Tester and MS are tightly coupled which allows
  debugging using standard tools

11
Debugging GMM code ...

• static void GMMDoRoutingAreaUpdate (
  GM_IE_UPDATE_TYPE RauType, BOOLEAN FirstAttempt
  )
• MMRAUpdPending FALSE
• GMRauType RauType
• GMStopT3302( )
• GMStopT3311( )
• if ( ! FirstAttempt )
• GMT3330Expiries 0
• if ( GMActState GMActDetachInit )
• GMStopT3321( )
• GMDetachPending TRUE
• if ( GMTriggerAction GM_GS_ATTACH_COMP )
• / Reinitialise the trigger action
  variable. /
• GMTriggerAction GM_NO_TRIGGER_ACTION

12
Highlights of our GSM/GPRS virtual test system

• Extremely efficient performance (around 1300
  tests in 20 minutes)
• Includes testing of DSP code
• About 30 man-years development effort (including
  test case development)

13
Drawbacks of our GSM/GPRS simulation

• Tester uses proprietary (in house) test script
  languages and encoders which are difficult to
  maintain
• It is difficult to write test cases
• Tester is not nicely layered as shown in the
  previous slide, so it is difficult to extend and
  maintain
• Summarizing the system can not be extended to
  implement an UMTS System Simulator

14
3GPP test model(TS 34.123-3)
15
Why we need a Test Model

• Main reason for us If we comply with the 3GPP
  Test Model we can use the TTCN test cases
  developped here at ETSI / STF 160
• In general
• Clear and stable interfaces to the SS enables
  manufacturers to develop the test equipment
• It reduces ambiguities within test case scenarios
• It enables outsourcing of testing activities and
  SW re-use
• It provides a common consens or understanding of
  the complete system to manufacturers and operators

16
A test case (1/2) ...

• Configure SS
• Configure PHY / L1
• Configure MAC
• Configure RLC
• Schedule and send System Information Blocks
• Test case preamble
• Bring UE into initial state (e.g. CS and PS
  registration)
• Perform Location Update procedure
• Perform GPRS Attach procedure

17
A test case (2/2) ...

• Test case body
• Stimulate the UE, e.g.
• Send X message to the UE, or
• Change cell power levels, or
• Trigger the UE via AT command to initiate a call
• Verify responses
• Match messages from the UE to expected values
• Assign a verdict (PASS, FAIL, INCONC)
• Test case postamble
• Complete signalling to bring UE into stable state

18
So, how to design a Virtual Tester which matches
the 3GPP model and our requirements ?
19
Problems designing an overall GSM/GPRS/UMTS Test
Env.

• The clean 3GPP model is not enough for a complete
  MS test environment
• We need to re-use tools, tracers, and most of all
  test cases developed for GSM in the new
  environment
• We can not afford to develop the UMTS test suite
  in house, we need to re-use the 3GPP tests
• The L1 and DSP simulation strategies for GSM do
  not match those of UMTS

20
Current approach (a compromise)

• Multi-threaded system The proper MS, the GSM SS,
  the UMTS SS and the SIM simulator
• All communicating via shared buffers
• The tick-master is the MS, when all jobs for
  current frame are completed, it issues a tick
  and all System Simulators prepare data (radio
  blocks) for next frame.
• Each SS will send a tick-ack to the MS when it
  is ready for next frame
• When all SSs are done the MS L1 engine will
  fetch or store a radio block

21
GSM/GPRS/UMTS Test Environment
22
Summary

• A Virtual Test Environment is an essential tool
• for development
• for quality assurance
• 3GPP test model
• A rough overview of our implementation

23
Thank you.