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OTA „ O ver T he A ir“ Test System Solutions for Wireless Devices

OTA „ O ver T he A ir“ Test System Solutions for Wireless Devices. Agenda. Part 1: OTA OTA performance standards Covered wireless standards CTIA RF-Tests and parameters System Solutions “Rohde & Schwarz TS9970” Part 2: EMC EMC-Tests of 3G mobile communication products

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OTA „ O ver T he A ir“ Test System Solutions for Wireless Devices

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  1. OTA „Over The Air“Test System Solutions for Wireless Devices

  2. Agenda • Part 1: OTA • OTA performance standards • Covered wireless standards • CTIA RF-Tests and parameters • System Solutions “Rohde & Schwarz TS9970” • Part 2: EMC • EMC-Tests of 3G mobile communication products • Overview of Wireless standards • EMC RF-Tests and parameters • System Solutions “Rohde & Schwarz TS9976/TS9982”

  3. USA Europe OTA Performance-Standards CTIA 2.1 OTA Performance for GSM, CDMA COST 273 SWG 2.2 OTA Performance for GSM / UMTS

  4. International America International GSM • GSM 850 • GSM 900 • E-GSM • R-GSM • GSM 1800 • GSM 1900 TDMA [IS-136] D-AMPS [IS-54] cdmaOne [IS-95] 1xEV-DV WCDMA- 3GPP/FDD [UTRA TDD HCR] cdma2000 1xEV-DO WCDMA- 3GPP/TDD International Bluetooth IEEE 802.11a/e/h/i IEEE 802.11b/e/i IEEE 802.11g IEEE 802.15.3a [UWB] IEEE 802.15.4 [ZIGBEE] IEEE 802.16 [Wireless MAN] IEEE 802.16a [WIMAX] Covered Wireless Standards Digital Cellular Phones / Data Wireless LAN & Broadband Wireless Access

  5. OTA RF Performance Parameters OTA Over The Air TRP Total Radiated Power MEG Mean Effective Gain MERP Mean Effective Radiated Power TIS Total Isotropic Sensitivity 3D Radiation Pattern MERS Mean Effective Radiated Sensitivity

  6. CTIA RF-Tests and parameters CTIA Tests Overview Section 1: Introduction Section 2: Scope of measurements Section 3: Test site characteristics & quiet zone accuracy (Chamber performance) Section 4: Range reference measurement (path loss of test system with calibrated antenna) Section 5: Test procedure radiated power (TRP) Section 6: Test procedure receiver performance (TIS) Section 7: Measurement Uncertainty

  7. TRP Parameters • 3D Integration of radiated power over sphere • Measured with 15° steps without Theta θ= 0° and 180° • 264 measurements per polarization • TRP is the single figure of merit • EUT Mode is stand-alone without any cables CTIA RF-Tests and parameters

  8. CTIA RF-Tests and parameters TIS Parameters • 3D Integration of receiver sensitivity over sphere • TIS, is utilizing BER or FER (Frame Error Rate) • TIS has to measured in 30° steps without Theta θ= 0° and 180° • 60 measurements per polarization • TIS is a single figure of merit • EUT Mode is stand-alone without any cables

  9. CTIA RF-Tests and parameters • Two methods are used for scanning the UT • Conical Cut • Great Circle Cut • Conical Cut: The UT rotates on the long axis (azimuth phi Φ) and the measurement antenna moves (elevation theta θ), above and below the level of the UT for each rotation. • Great Circle Cut: The measurement antenna is fixed and the UT rotates in two axes (azimuth phi Φ and elevation theta θ) in sequential order.

  10. CTIA RF-Tests and parameters Typical Setup for a Conical Cut

  11. CTIA RF-Tests and parameters Typical Setup for a Great Circle Cut

  12. CTIA RF-Tests and parameters • Measurement antenna: • must be capable of two orthogonal linear polarizations, • simultaneous measurement recommended (repositioning errors) • Conditions: • Free Space • Simulated use (with SAM head phantom) • left and right ear • Extended and retracted EUT antenna (if applicable) • Phantom • completely filled (bubble size Ø < 25 mm) • weekly checks of liquid • Measurements on all EUT configurations (i.e. battery packs) unless demonstrated, that effect is negligible • FER / BER reported from mobile to base station generator (if applicable)

  13. CTIA RF-Tests and parameters • EUT antenna positioned at the centre of the sphere. • Rotation around Ear reference point, alternative: rotation point centre of phantom (additional uncertainty → CTIA G.7.1) • Polar coordinates - independent from test procedure • Measurement data weighed by sin θ Great Circle Cut: • TIS: 6 Theta-cuts (T0, T30, …, T150) • T0: Test ear closest to the ground (Reason: Definitively no air bubble) • TRP: 10 Theta-cuts T0, T15, …, T165

  14. CTIA RF-Tests and parameters Test site characteristics: • Minimum test distance from antenna phase centre, (alternative: tip of antenna): • Cellular (824 – 894 MHz) > 1,09 m • PCS (1850 – 1990 MHz) > 1,19 m • The strictest of the 3 Far field criteria's should be taken • Near field measurements will be considered, when they have demonstrated to be adequate.

  15. CTIA RF-Tests and parameters Test site accuracy: Ripple test • Verification of system performance, especially reflectivity of chamber inclusive all installations (e.g. Positioner) • All equipment used for normal testing shall be in place • Two different tests: • Theta axis ripple test • Phi axis ripple test • Ripple test value should be < 1 dB

  16. CTIA RF-Tests and parameters Test site accuracy, test equipment: • Sleeve Dipole and Loop antenna optimized for: • Test frequencies 836,5 1MHz, 1880 1MHz • asymmetry <  0,1 dB in azimuth • Low dielectric supportstructure (for positioning the probe antennas) • Measurement antenna (e.g. Horn or dipole used during antenna measurements) • Signal Generator / Spectrum Analyzer or Network Analyzer

  17. CTIA RF-Tests and parameters Test site accuracy, test equipment: • Probe symmetry test: • Qualification of the symmetry of the probe antennas • With azimuth scan of 2° step size The probe symmetry is not part of the ripple test but a certification step to ensure that the probe satisfy the ripple test.

  18. CTIA RF-Tests and parameters Test site accuracy, test procedure: • Phi Φaxis ripple test: • Quiet zone cylinder 300 mm Ø and 300 mm long • Positions Phi Φ axis: -150, 0, + 150 mm • Offset: centre and circle 150 mm (6 positions) • Azimuth rotation, measurement every 2°, Theta θ= 90° constant • Measurement antenna co polarized • low permittivity dielectric support • signal > 40 dB over noise floor • file export to excel

  19. CTIA RF-Tests and parameters Test site accuracy, test procedure: • Phi Φaxis test geometry:

  20. CTIA RF-Tests and parameters Test site accuracy, test procedure: • Theta θ axis test: • Offset 150 mm in each axis (Seven positions) • Theta θ rotation -165° - 165° • Step size 2° • Phi Φ=0°

  21. CTIA RF-Tests and parameters Test site accuracy, test procedure: • Theta θ axis test geometry:

  22. CTIA RF-Tests and parameters Test site accuracy, test procedure: • Allowances and adjustments to Phi Φ axis: • Several exceptions for other measurement points, angular stepping etc.

  23. CTIA RF-Tests and parameters Test site accuracy, test procedure: • Allowances and adjustments to Phi Φ axis:

  24. CTIA RF-Tests and parameters Range reference measurements: • Reference measurement precondition for TRP, EIRP, TIS or EIS • Typically dipole or standard gain horn as Substitution Antenna Under Test (AUT) • Measurement for each polarisation and possible signal path • Repeated at least annually (recommendation monthly or quarterly) and in case of site changes • Recommendations: • Low uncertainty precision calibrated sleeve dipole < 2,5 GHz • Standard gain horn > 2,5 GHz, other antennas possible • Cable, ferrite bead treated and routed, to minimize effects • Attenuators (3 to 10 dB) to reduce VSWR effects

  25. CTIA RF-Tests and parameters Range reference measurements: • Test frequencies (at least):

  26. PRA PTE PSG PRX Spectrum analyzer Signal Generator clSG-RA clTE-RX PL Total Path Loss PRA PTE PMA r clTE-RX clMA-TE clSG-RA PISO GMA GRA PRX PSG Spectrum analyzer Signal Generator CTIA RF-Tests and parameters Range reference measurements: • Test procedure: • Two steps Reference calibration • Cable • Range Reference Test

  27. CTIA RF-Tests and parameters Range reference measurements: • Improved accuracy by use of power meter (uncertainty) • TRP: correction of receiver value • TIS: Absolute measurement of received power Remarks: max. 4752 measurement points

  28. CTIA RF-Tests and parameters • Radiated power (TRP): • All evaluations will be performed: • In “conversational” mode • At maximum transmit power • Products supporting multiple air-interface technologies will be tested in accordance with all relevant test procedures • Test results will be provided for each test performed in the format defined

  29. CTIA RF-Tests and parameters Radiated power (TRP) AMPS: • Three channel pairs • Free space and simulated use with SAM (phantom head) • Antenna extended and retracted • Power at antenna connector measured (if applicable) • Base station parameters are defined

  30. CTIA RF-Tests and parameters Radiated power (TRP) CDMA: • Three channel pairs each band • Free space and simulated use with SAM (phantom head) • Antenna extended and retracted • Power at antenna connector measured (if applicable) • Base station parameters are defined

  31. CTIA RF-Tests and parameters Radiated power (TRP) TDMA: • Three channel pairs each band • Free space and simulated use with SAM (phantom head) • Antenna extended and retracted • Power at antenna connector measured (if applicable) • Base station parameters are defined

  32. CTIA RF-Tests and parameters Radiated power (TRP) GSM: • Three channel pairs each band • Free space and simulated use with SAM (phantom head) • Antenna extended and retracted • Power at antenna connector measured (if applicable) • Base station parameters are defined

  33. CTIA RF-Tests and parameters Radiated power (TRP) GSM: • GPRS: • Maximum number of uplink time slots supported by the EUT shall be utilized • coding scheme CS-1Test as GSM • head adjacent testing only, if GPRS is supported by the device in this mode (e.g. VoIP) • EGPRS: • Maximum number of uplink time slots supported by the EUT shall be utilized • coding scheme MCS-5Test as GSM • head adjacent testing only, if EGPRS is supported by the device in this mode (e.g. VoIP)

  34. CTIA RF-Tests and parameters Receiver performance (TIS): • Complete measurement at 3 channels as TRP • Relative measurement on intermediate channels (some channels may be omitted, as long as spacing < 500 kHz) • All measurements for free space and against phantom, antenna extended and retracted • Sufficient number of bits or frames for confidence interval  95 % • 30° steps (due to less accurate measurement procedure, goal: TIS accuracy < 2 dB with 95% certainty)

  35. CTIA RF-Tests and parameters Receiver performance (TIS): • No TIS measurement forAMPS • CDMA: • FER ≤ 0,5% with 95% confidence • Also measurement at antenna connector (if applicable) • Communication tester setup same as TRP • forward power for 0% FER • power control closed loop • If test point is in a null, forward power have to be raised • Near the sensitivity level:  500 frames(≤ 2000 frames limit possible), power step ≤ 0,5 dB • For final measurement: • Power control “Always Up”

  36. CTIA RF-Tests and parameters CDMA Receiver performance (TIS): • Forward link power and power control set back to default for the next measurement point • The measurement range should be 30 dB above the lowest sensitivity level • Measurement of alternate points in the sensitivity curve are allowed, if the curve is calibrated (no interpolation allowed). • Relative sensitivity on intermediate channels: • Choose position and polarization for best radiated sensitivity (= Reference channel; one position for all 3 bands, if within 3dB for the best channel) • Base station signal raised by 5 dB • FER measurement

  37. CTIA RF-Tests and parameters CDMA Receiver performance (TIS): • Relative sensitivity on intermediate channels:

  38. CTIA RF-Tests and parameters TDMA Receiver performance (TIS): • For TDMA TIS is not required • The procedure is for information only • The Mobile must be set into loop back mode. • The base station power has to be lowered until a 3% BER (± 0,1%) with a bit rate of 100 kbit is measured.

  39. CTIA RF-Tests and parameters GSM Receiver performance (TIS): • Class II Residual Bit Error Rate (RBER) 2,44% with 95% confidence level • Communication tester setup same as TRP, • forward power for 0% RBER, • power control level (PCL) high enough for no communication errors (no need for maximum power at each point) • loop back mode • If test point is in a null, the forward power has to be raised • Near the sensitivity level: • IF  135 frames (≤ 1000 frames limit possible) • power step ≤ 0,5 dB • Final measurement: • Power level control maximum power (also for BER reference curve) • set back to default for next test point

  40. CTIA RF-Tests and parameters GSM Receiver performance (TIS): • Measurement range of 30 dB above the lowest sensitivity level is acceptable. • Measurement of alternate points in the sensitivity curve are allowed, if the curve is calibrated (no interpolation). • Relative sensitivity on intermediate channels: • Choose position and polarization for best radiated sensitivity (= Reference channel; one position for all 3 bands, if within 3dB for the best channel) • Base station signal should be raised by 5 dB • RBER measurement

  41. CTIA RF-Tests and parameters GPRS/EGPRS Receiver performance (TIS): • The Block Error Rate (BLER) 10% is based on 2000 received blocks with 95% confidence level. • Communication tester setup same as TRP • but forward power for 0% BLER at CS-1 • power control level (PCL) high enough for no communication • errors (no need for maximum power at each point) • loop back mode • If test point is in a null, forward power have to be raised • Near the sensitivity level:  200 blocks (≤ 2000 frames limit possible), power step ≤ 0,5 dB

  42. CTIA RF-Tests and parameters GPRS/EGPRS Receiver performance (TIS): • Final measurement: • Power level control maximum power (also for BER reference curve) • set back to default for next test point • Measurement range of 30 dB above the lowest sensitivity level is allowed • Measurement of alternate points in the sensitivity curve is allowed, if the curve is calibrated (no interpolation). • Relative sensitivity on intermediate channels: • Choose position and polarization for best radiated sensitivity (= Reference channel; one position for all 3 bands, if within 3dB for the best channel) • Base station signal raised by 5 dB • BLER measurement

  43. CTIA RF-Tests and parameters Alternative Procedure for multi-protocol DUT: • Requirement: More than one protocol in the same frequency band • Procedure • Complete TRP (or TIS) measurement of 1st protocol (voice digital protocol preferred) • Set DUT to worst case position and polarization • Repeat measurement with 1st protocol at this point • Switch without any change to 2nd (or further) protocols • Measure value of second protocol • Result for 2nd protocol : Extrapolate TRP (or TIS) value by the difference between the two measurements

  44. CTIA RF-Tests and parameters Measurement uncertainty: • Uncertainty is based on the ISO Guide • It is recommended to use same setup for measurement as for reference calibration (no individual calibration factors on single components) • Detailed lists for the different contributions • Expanded uncertainty must not exceed ± 2dB at 95% confidence level

  45. CTIA RF-Tests and parameters

  46. Facts of TRP Measurements • 264 Measurments per DUT • 425 Samples / GSM-Burst ( 300 requested), FSP internal measurement routine • Test time for complete scan, 2 polarisations, 3 channels: typ. 20 min (3 bands, 3 channels typ. 40 min.) • Complete measurement for GSM: • 3 bands • 2 polarizations • 2 configurations (antenna extended and retracted) • 3 modes (free space and simulated mode (left / right ear) Result = 240 min  (4 h)

  47. Facts of TRP Measurements • 4 h Test time per GSM DUT causes problems to the system stability: • 264 points per TRP measurement • 2 configurations (antenna inside and retracted) • 3 modes (free space and simulated mode (left / right ear) • 2 polarizations Result = 3168 number of switch cycles (without band handovers) Dual Analyzer systems will not increase the measurement speed tremendously but the system stability will be highly improved

  48. Facts of TIS Measurements Problem: Long measurement time for BER-Measurements • Measurement methode (fast leveling to RxLev): • RxLev (reception level of DUT) to requested BER of previous measurement point is known • Fast leveling to the same RxLev (only power measurement) • BER-Measurement with 200 Frames (duration approx. 1s / measurement; CTIA-request min. 135 Frames) • Leveling to requested BER-Value • Total measurement time for TIS (GSM, 1 chanel): 4 to 6 h In total 3 channels with 2 configuration (antenna in and retracted), 3 conditions (FreeSpace / simulation mode) are necessary.

  49. Facts of TIS Measurements New technique by R&S TS9970: Alternative test procedure statistical BER-Measurement with 95% confidence level • Early pass / fail decision • Measurement will be extremly fast if the level is far away from the target level. (please see Fig. 1) • If close to target BER then extended measurement time for 95% confidence level necessary • fast leveling to the target level = reduction of measurement time.

  50. Facts of TIS Measurements Fig.1 single limit confidence BER

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