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Ad-hoc workgroup report on New Technologies

Ad-hoc workgroup report on New Technologies. TC-34 ad-hoc taskgroup Chair : David Case. Overview. This is report provides an overview of the current generation of technologies as well the SAR test procedures from the FCC to evaluate these product compliance.

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Ad-hoc workgroup report on New Technologies

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  1. Ad-hoc workgroup report on New Technologies TC-34 ad-hoc taskgroup Chair : David Case

  2. Overview • This is report provides an overview of the current generation of technologies as well the SAR test procedures from the FCC to evaluate these product compliance. • This discussion was to provide information for the TC34 and TC 106 workgroups to consider SAR measurement difficulties for today’s technology and to prepare for the next revision of the IEEE 1528 / EN 62209.2 standards. • The technologies addressed in this discussion are Wi-Fi, WiMAX, 3G as well as discussion on the FCC test guidelines for laptops

  3. 802.11 a/b/g/n bands • Bandwidths for DTS 20 MHz, 40 MHz • FH BW <1MHz to <5MHz • Transmitter power based on FCC or ETSI rules. • Frequency TX power Max EIRP • 2400-2483.5MHz 1W 4W EIRP* • 5150-5250 MHz 50mW 200mW EIRP • 5250-5350 MHz 250mW 1W EIRP** • 5470-5725MHz 250mW 1W EIRP • 5725 – 5850MHZ 1W 4W EIRP • * ETSI max is 100mW EIRP • **ETSI Max is 200mW EIRP

  4. 802.11 based devices • Frequency 4940- 4990 MHz Public Safety • Transmitter power +20dBm • +33dBm non 802.11 • BW Low TX power High TX 1MHz +7dBm +20dBm 5 MHz +14dBm +27dBm 10MHz +17dBm +30dBm 15MHz +18.8dBm +31.8dBm 20MHz +20dBm +33dBm

  5. 802.11Technical info • 802.11b/g modulations BPSK, QPSK, QAM, CCK , OFDM Data Rates 1- 54Mbps • 802.11a modulations BPSK, QPSK, OFDM Data Rates 6 – 54Mbps • 802.11n OFDM Modulations to 108Mbps • 4.9GHz OFDM • Proprietary turbo, half and quarter rate modes • Switched diversity antenna capability • Operating modes – ad-hoc and infrastructure • Dynamic communication protocols (varying power and Tx duty factor) • Module transmitters

  6. 802.11 Issues • Normal operating modes unsuitable for SAR testing • Test modes do not accurately reflect real operation modes • SAR of switched antenna diversity cannot easily be measured • Other complex antennas require additional SAR evaluation • Transmit duty cycle during normal use varies usage and traffic conditions. • Burst duty factor and burst crest factor corrections are random, compensation difficult. • Modules can be used in variety of hosts with different antenna configurations , making testing of stand alone modules more difficult to simulate results in variety of hosts.

  7. 802.11 SAR Test Recommendations • Test with transmitter set at highest output power for each modulation chosen. • Until duty cycle issue is resolved test at 100% duty cycle understanding that in normal operation duty factor could be greatly reduced. • Consider verifying output linearity and duty cycle • Lowest data transfer rate typically uses lower order modulation that require higher average output power but may need to verify SAR for higher order modulations according to output power requirements.

  8. 802.11 SAR Test Recommendations • Test at least one high order (OFDM) and one low order modulation (BPSK). If the maximum average TX power is more than 0.25dB higher for other modulations, additional testing of other modulations may be required • Testing of additional BW can be done according to the output power requirements for the various Bandwidths.. • Radio modules will require appropriate host platforms to conduct SAR tests : example laptop, PDA, etc for use as such platforms.

  9. Summary • 802.11 devices are becoming more pre valiant as standard equipment in devices such as wireless phones, laptops, handheld. • 802.11 devices are not just for use in the unlicensed band but now are being designed and deployed for licensed services as well. • FCC 802.11 SAR test procedure needs to be reviewed by the TC 34 committee to consider incorporating some of the requirements.

  10. FCC 3G Document

  11. Introduction to WWAN SAR • 3 main WWAN technologies dominate international markets: GSM, CDMA, WCDMA • Devices must be configured in an appropriately and consistent manners • Configurations must have acceptable PAR within SAR measurement equipment capabilities • Configurations must be repeatable • WWAN technologies are complicated, but fortunately wireless standards committees have test configurations that can be utilized for SAR testing • FCC has released guidelines for SAR testing in reference to US requirements • FCC documents can be referenced to create IEEE documents specifying technology configurations required for SAR testing

  12. Dominant WWAN Parameters Impacting SAR • Peak to Average (PAR) • Impact: PAR vs Probe linear response impacts SAR results accuracy • WWAN waveforms have PAR ranging from 1 dB to >5dB • Solution: Identify low PAR waveforms and mandate for SAR testing • Channel Configurations • Impact: Channel configuration can impact maximum output power and PAR • Variety of baseband physical channel types/configurations summed together and frequency up-converted to generate mobile transmit signal • Some channel configurations result in transmit power reduction defined by WWAN standards (ie high data rate configuration could reduce TX power to meet emissions requirements) • Solution: Mandate channel configurations that achieve maximum output power with low PAR • Configuring for max power • Impact: Mobile device may not be configured to transmit maximum power • Different WWAN technologies have different procedures to configure mobile devices to transmit at max power • Solution: Identify methods for configuring technologies for maximum output power and identify any problematic configurations/procedures • Transmitter Modulations • Impact: Effects PAR • Different technologies incorporate different modulations for the mobile transmitter • Solution: Identifying channel configurations with low PAR and consistent modulation schemes

  13. WWAN Technology Summary

  14. FCC 3G Document Status • Current FCC 3G Document defines CDMA/WCDMA test practices currently used by industry • Document defines test modes used for RF safety testing • Guidelines leverage from test modes defined by 3GPP and 3GPP2 standards bodies • Release of document has helped to bring consistency to WWAN SAR reports • Document needs some subtle changes to extend applicability of the document to future devices • Modification topics for discussion are in the following slides

  15. International WWAN Bands

  16. Addressing Configuration Requirements • WWAN standards identify channel configurations and procedures for configuring devices for RF conformance testing • Standards define many different configurations for diverse set of RF tests. • Max power and emissions test configurations can be used for SAR testing • Only a subset (or just one configuration) is applicable to SAR testing • Standards define procedures for configuring device to transmit at max power • WWAN power control schemes make configurations for maximum power easy • FCC’s 3G document has identified technologies configurations required FCC SAR testing based on the industry standards • FCC 3G document can be leveraged upon to generate IEEE configuration guidance document

  17. Suggested Modifications (3G Document) • Add some verbiage for multi mode devices (CDMA + GSM/GPRS/EDGE + WCDMA) limiting test data to highest TX power modes. • Increase power variance between modes beyond 0.25 dB to determine additional SAR test requirements if >75% margin • 0.25 dB is within the measurement error of test equipment • Address test software vs. call box call support

  18. Suggested Modifications (3G Document) Continued • Add some commentary about simultaneous TX (BT, WLAN) • Add tables with standards references • Change 1x RC3 reference to be consistently SO55 (remove TDSO/S32) • Refine appendix information • Reduce and clarify existing information

  19. FCC Notebook SAR Evaluation

  20. Introduction • Current SAR measurement procedures applicable to handset designs • Future/current wireless devices include embedded Notebook computers, Ultra Mobile PCs, cameras, TBD consumer electronic devices • No test measurement procedures exist • Future devices incorporating wireless transmitters is limitless and thus difficult to establish procedures

  21. Problem Statements • Absence of non-handset SAR procedures is causing problems for the wireless product industry • Wireless Industry has requirements for two types of guidance: • Measurement procedures for non-handset devices • Test requirements for devices with multiple technologies • These devices are in the market today, so these procedures need to be addressed quickly • Industry currently completes a large number of burdensome SAR test cases that result in very low SAR results (>10dB of margin)

  22. Factors for Consideration • Separation Distance from user: Some devices provide separation distance from user such that SAR testing may not be applicable • Is SAR really necessary for a 500mW transmitter with 10cm of separation distance? • Simultaneous transmission of multiple technologies: How does simultaneous transmission impact RF safety? • Depending on the separation distances and transmit power, SAR testing may not be applicable • If antennas are shared, separation distance to user must be considered • If different antennas, the separation distance between the antennas and the interaction between the antennas must be considered

  23. FCC Notebook Document • Released by FCC in Dec 2007 • Allows reduction in SAR test requirements depending on TX power and separation distances • Reduces test requirements for changes/variations in similar notebook models • Excellent first step in identify ways to reduce unnecessary testing • Current document only applies to very low power applications • Future work required to further reduce test cases

  24. Discussion points for Notebook Document • Need further discussion on antenna to antenna separation distances as they relate to impact on SAR measurement results • Support simulations? • Compare simulations with actual SAR measurement of notebook computers • Need further discussion on antenna to user separation distance • At what distance does SAR measurement become negligible vs. FCC and international SAR limits • Use test data of SAR measurements on actual notebook computer products as part of the equation

  25. Summary • Wireless transmitters are being incorporated into a diverse type of form factor end product • Guidelines defining test procedures are required to address RF safety testing • Future work is required to expand on FCC’s first attempt to address the test procedures and establish industry wide test practices

  26. SAR Test Complexities with WiMAX

  27. WiMAX Forum 802.16e Bands • OFDMA Signal with different FFT sizes and modulations available • Multiple Bandwidths Supported (5, 7, 8.75, 10 MHz & future may include 20 MHz) • Transmitter power based Device Power Class and Open loop and Closed Loop rules. Typical range 24 – 33 dBm • Frequency Chn BW(MHz) FFT Size • 2.3 – 2.4 GHz 5, 8.75, 10 512, 1024, 1024 • 2.496-2.69GHz 5,10(both must be supported) 512, 1024 • 3.3 – 3.4 GHz 5, 7, 10 512, 1024, 1024 • 3.4 – 3.8 GHz 5, 7, 10 512, 1024, 1024

  28. Dominant WiMAX Parameters Impacting SAR • Frame Configurations & Peak to Average (PAR) • Impact: Frame configuration can impact maximum output power and PAR • Variety of modulations, flexible allocation of number of sub-carriers in FFT, different coding available for each sub-carrier, flexible duty cycle. • Solution: Mandate frame configurations that achieve maximum output power with low PAR • Configuring for max power • Impact: Mobile device may not be configured to transmit maximum power • Lack of loop back testmode makes confirmation of power and frame control difficult. Test equipment with required level of frame and power control is still under development. • Solution: Identify methods for configuring technologies for maximum output power and identify any problematic configurations/procedures

  29. Other Issues Impacting SAR Measurements of WiMAX DUT • Current Probe Calibration methods may not address complexity of WiMAX signals. • Power measurement profiles on current equipment may not sense the frame correctly and miss the edges. New profiles or equipment may be needed.

  30. MIMO Technologies

  31. MIMO In Various Market • 802.11n- WLAN • 802.16 – WWAN • High Speed Downlink Packet Access (HSDPA) for W-CDMA UMTS (3GPP TS25-876): 28 Mbps peak rates in 5 MHz channel • 4MIMO-OFDM strong candidate for 4G systems: under investigation by 4G Mobile Forum and Wireless World Research Forum (source: Qualcomm MIMO presentation @TCBC workshop)

  32. MIMO Technologies • MIMO = Multiple-In; Multiple-Out • MIMO requires signal processing on transmitter and receiver • Multiple-In= Multiple Receiver Chains • Multiple-Out=Multiple Transmitter Chains • Chains= No. of RX or TX elements • 2x3 MIMO= 2 Transmitter chains and 3 receiver chains. • 2x2 MIMO= 2 Transmitter chains and 2 receiver chains.

  33. MIMO Technologies • MISO: Multiple-In (Multiple Receiver Chain); Single-Out (Single Transmitter Chain) • SISO: Single-In (One Receiver Chain); Single-Out (One Transmitter Chain) • CDD/ Legacy: Cyclic Delay Diversity: only applicable to OFDM (Orthogonal Frequency Division Multiplexing) modulation (802.11g and/or 802.11a)- 802.11b does not use OFDM modulation (CCK, DQPSK, DBPSK). • CDD/ Legacy: can increase frequency selectivity of the channel seen by the receiver, which results in cyclic delay diversity (CDD) and achieves spatial diversity. • STBC/Legacy : Space-Time Blocked Coding: to improve bit error performance of the whole wireless system • SDM/MIMO: Spatial Division Multiplexing : SDM spatially multiplexes multiple independent data streams, transferred simultaneously within one spectral channel of bandwidth. MIMO SDM can significantly increase data throughput as the number of resolved spatial data streams is increased.

  34. MIMO Antenna Locations

  35. MIMO Antenna Locations

  36. MIMO Power • 802.11b average power is higher than 802.11g legacy or 802.11g/40MHz (approxi. 3dB higher) • TX chain#0 and chain#2 average output power is within 0.5 dB • TX chain#0 and chain#2 peak output power is within 1 dB.

  37. MIMO Output Power 2.4GHz Band

  38. MIMO Power Proposed 802.11 WORST-CASE CONFIGURATION AND MODE (based upon measurement) • 802.11b mode, 20 MHz Channel Bandwidth, 1 Mb/s, CCK Modulation • 802.11g mode, 20 MHz Channel Bandwidth, 6 Mb/s, OFDM Modulation, Spatial Stream 1.(SAR is not required when the max. average output power is less than ¼ dB higher than the corresponding 802.11b channel) • 802.11a mode, 20 MHz Channel Bandwidth, 6 Mb/s, OFDM Modulation, Spatial Stream 1. • 802.11n HT20 mode, 20 MHz Channel Bandwidth, MCS0, 6.5 Mb/s, OFDM Modulation, Spatial Stream 1. • 802.11n HT40 mode, 40 MHz Channel Bandwidth, MCS0, 13.5 Mb/s, OFDM Modulation, Spatial Stream 1.

  39. MIMO Summary • Shall average output power measure with combiner? Or on individual TX chain? • Shall MIMO device be measured with both transmitting chains-ON or individual TX chain is enough? • Test Software provided can configure MIMO to transmit on one of chain or all chains simultaneously • When one of TX chain antenna is portable (<20cm) and the other TX chain antenna is mobile (>20cm), test mode shall be defined.

  40. New Taskgroup issues • Provide information on test procedure used to determine worst case modes for 802.11. • Develop plan for additional verification of proposed 802.11 modes SAR test requirements – • Develop plan for addressing WWAN / WiMAX technologies issues for SAR test standard. • Develop plan to start addressing non handheld devices with multiple radios • Recommendations for above due by April TC34 conference call.

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