1. Tuesday, May 09, 2006Elcoteq Presentation / Jussi Savolainen1 S-38.3310 Tietoverkkotekniikan diplomityöseminaari 09.05.2006 Title: Automatic Bluetooth Radio Frequency Measurement System Author: Jussi Savolainen Supervisor: Prof. Sven-Gustav Häggman Instructor: Petteri Yrjälä, M.Sc. Work carried out at: Elcoteq Design Center Oy, Salo

2. Tuesday, May 09, 2006Elcoteq Presentation / Jussi Savolainen2 Presentation outline Background Research problem Research methods Bluetooth essentials Bluetooth RF measurements System setup Software implementation Conclusions and further work

3. Tuesday, May 09, 2006Elcoteq Presentation / Jussi Savolainen3 Background Bluetooth RF conformance testing by far the most expensive (time and cost) of the conformance tests, because –off-the-shelf test systems > 1 M€ (cost) –response time using external test houses too long (time) Projects need a heap of test data in a short amount of time for statistical analysis, etc. Failing in type approval tests is expensive

4. Tuesday, May 09, 2006Elcoteq Presentation / Jussi Savolainen4 Research problem How to automatically perform the Bluetooth RF conformance tests according to Bluetooth Test Specification version 2.0+EDR in prequalification phase of the design How to perform the tests simultaneously for a number of devices How to support different Bluetooth products and product types

5. Tuesday, May 09, 2006Elcoteq Presentation / Jussi Savolainen5 Research methods Literary study (Bluetooth RF specification, Bluetooth test specification, measurement device vendor application notes, etc.) Vendor audits/interviews HW Designer interviews UI usability study Data storage study

6. Tuesday, May 09, 2006Elcoteq Presentation / Jussi Savolainen6 Bluetooth essentials Bluetooth connects portable or fixed equipment, and it is a cable replacing technology, which is cheap and robust with low power consumption Technology initially developed at Ericsson in 1994 Bluetooth SIG established in 1998, first version of specification out same year Most recent version 2.0+EDR came out in 2004 with support to higher data rates than previously Operates on unlicensed (but not unregulated!) 2.4GHz ISM band M S S S M/S S piconet 1 piconet 2 psps sbsb psps Scatternet with two piconets

7. Tuesday, May 09, 2006Elcoteq Presentation / Jussi Savolainen7 Bluetooth essentials – protocol stack Bluetooth protocol stack is a fuzzy structure Controller and Host can be separated using HCI, chipset and applications implemented separately Thesis discusses mainly radio layer RADIO BASEBAND AND LINK CONTROLLER LINK MANAGER L2CAP HOST CONTROLLER INTERFACE RFCOMM OBEXWAP TCS SDP APPLICATIONS two- way voice control data HOST CONTROLLER

8. Tuesday, May 09, 2006Elcoteq Presentation / Jussi Savolainen8 Bluetooth essentials – packet structure Basic rate 1Mb/s Enhanced Data Rate 2Mb/s or 3Mb/s in EDR packets modulation is changed during the burst from 2FSK to PSK (backwards compatible) EDR mostly affects radio layer LSB ACCESS CODE HEADER MSB PAYLOAD 68/72b54b0-2745b LSB ACCESS CODE HEADER MSB PAYLOAD 72b54b16-8200b GUARDSYNC 5 µs11 µs 2FSK PSK General basic rate packet format General enhanced data rate packet format

9. Tuesday, May 09, 2006Elcoteq Presentation / Jussi Savolainen9 Bluetooth RF measurements - basics Device Under Test (DUT) can be placed to test mode, which allows configuration and control of the DUT Some tests must be performed under extreme temperature and voltage conditions Tests divided in transmitter (TX), receiver (RX) and transceiver (TRC) measurements TX and RX tests according to Bluetooth RF test specification TRC tests according to ETSI EN 300 328

10. Tuesday, May 09, 2006Elcoteq Presentation / Jussi Savolainen10 Bluetooth RF measurements – TX tests MeasurementDescription Output powerMaximum peak and average power of the burst Power densityMaximum RF-output power density Power controlVerification of power control Frequency rangeEmissions inside the operating frequency within limits 20dB bandwidthEmissions inside the operating frequency within limits Adjacent channel powerEmissions inside the operating frequency within limits Modulation characteristicsModulation index Initial carrier frequency toleranceTransmitter carrier frequency accuracy Carrier frequency driftTransmitter centre frequency drift within a packet EDR relative transmit powerDifference in power during 2FSK and PSK portions of packet EDR carrier frequency stability and modulation accuracy Carrier frequency stability and modulation accuracy EDR differential phase encodingDifferential phase encoded data correctness EDR in-band spurious emissionsUnwanted signal levels on adjacent channels TX tests either power measurement as function of frequency or frequency as function of time

11. Tuesday, May 09, 2006Elcoteq Presentation / Jussi Savolainen11 Bluetooth RF measurements – RX tests RX tests are BER measurements performed under different stimulus conditions MeasurementDescription Sensitivity – Single slot packetsRequired sensitivity with non-ideal signal Sensitivity – Multi slot packetsRequired sensitivity with non-ideal signal C/I performanceSensitivity in presence of co-/adjacent channel interference Blocking performanceSensitivity in presence of out-of-band interference Intermodulation performanceVerification of receiver’s intermodulation characteristics Maximum input levelReceiver performance in presence of high power signal EDR sensitivityRequired sensitivity with non-ideal signal EDR BER floor performanceReceiver performance for 10^-5 BER EDR C/I performanceSensitivity in presence of co-/adjacent channel interference EDR maximum input levelReceiver performance in presence of high power signal

12. Tuesday, May 09, 2006Elcoteq Presentation / Jussi Savolainen12 Bluetooth RF measurements – TRC tests Out-of-band spurious emissions measured according to ETSI EN 300 328 Does not belong to Bluetooth conformance tests Measures harmonics of the carrier signal, cabinet radiation and modulation products

13. Tuesday, May 09, 2006Elcoteq Presentation / Jussi Savolainen13 System setup All Bluetooth RF conformance tests and out-of-band spurious emission measurement must be performed automatically with one setup 12 DUTs measured simultaneously Capable of measuring any Bluetooth device which implements at minimum the controller Relay box RF Shield Multiplexer 1x12 Climate chamber Multiplexer 1x4 IQ CW Spectr An BT tester Multiplexer 1x12 GSM Signaling GSM Multiplexer 1x4 Multiplexer 1x4 ATT

14. Tuesday, May 09, 2006Elcoteq Presentation / Jussi Savolainen14 System setup - equipment DeviceDescription BT testerBluetooth signaling tester capable of performing EDR measurements RF shieldAttenuates interfering RF signals Temperature chamberUsed in extreme temperature conditions (typ. -20ºC and +55 ºC) Relay boxUsed to filter unwanted frequencies e.g. in out-of-band spurious measurement IQSignal generator capable of producing Bluetooth modulated interfering signals CWSignal generator capable of producing continuous wave signals Spectr anSpectrum analyzer capable of gating GSM signalingGSM & 3G signaling tester for coexistence testing Altogether ~ 200 k€ Calibration of the transmission paths from 30MHz to 13GHz with 1MHz steps

15. Tuesday, May 09, 2006Elcoteq Presentation / Jussi Savolainen15 Software implementation - UI

16. Tuesday, May 09, 2006Elcoteq Presentation / Jussi Savolainen16 Software implementation – data storage System creates ~50Mb/day of data  text files or excel sheets are not an option Writer (test system/test engineer) and reader (customer project/RF designer) are separated Graphs and reports must be easily extractable from database Short response time for new graphs and reports

17. Tuesday, May 09, 2006Elcoteq Presentation / Jussi Savolainen17 Conclusions and further work This type of system is never finished as interface to a new DUT must be built every time and data storage is updated Error handling updates Calibration Measurement equipment SW updates

18. Tuesday, May 09, 2006Elcoteq Presentation / Jussi Savolainen18 ¿Questions? DANKE!

19. Tuesday, May 09, 2006Elcoteq Presentation / Jussi Savolainen19 World’s leading EMS provider to communications technology customers