Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Multi-band OFDM Physical Layer Proposal Update] Date Submitted: [10 May, 2004] Source: [Presenter 1:Charles Razzell] Company [Philips ] [[see page 2,3 for the complete list of company names, authors, and supporters] Address [1109, McKay Drive, San Jose, CA 95131, USA] Voice:[408-474-7243], FAX: [408-474-xxxx], E-Mail: [charles.razzell@philips.com] Re: [This submission is in response to the IEEE P802.15 Alternate PHY Call for Proposal (doc. 02/372r8) that was issued on January 17, 2003.] Abstract: [This document describes the Multi-band OFDM proposal for IEEE 802.15 TG3a.] Purpose: [To give proposal updates between March and May 04.] Notice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15.

2. Authors of the MB-OFDM Proposalfrom 17 affiliated companies/organizations Femto Devices: J. Cheah FOCUS Enhancements: K. Boehlke General Atomics:N. Askar, S. Lin, D. Furuno, D. Peters, G. Rogerson, M. Walker Institute for Infocomm Research: F. Chin, Madhukumar, X. Peng, Sivanand Intel:J. Foerster, V. Somayazulu, S. Roy, E. Green, K. Tinsley, C. Brabenac, D. Leeper, M. Ho Mitsubishi Electric:A. F. Molisch, Y.-P. Nakache, P. Orlik, J. Zhang Panasonic: S. Mo Philips: C. Razzell, D. Birru, B. Redman-White, S. Kerry Samsung Advanced Institute of Technology:D. H. Kwon, Y. S. Kim Samsung Electronics: M. Park SONY:E. Fujita, K. Watanabe, K. Tanaka, M. Suzuki, S. Saito, J. Iwasaki, B. Huang Staccato Communications:R. Aiello, T. Larsson, D. Meacham, L. Mucke, N. Kumar, J. Ellis ST Microelectronics:D. Hélal, P. Rouzet, R. Cattenoz, C. Cattaneo, L. Rouault, N. Rinaldi,, L. Blazevic, C. Devaucelle, L. Smaïni, S. Chaillou Texas Instruments:A. Batra, J. Balakrishnan, A. Dabak, R. Gharpurey, J. Lin, P. Fontaine, J.-M. Ho, S. Lee, M. Frechette, S. March, H. Yamaguchi Alereon: J. Kelly, M. Pendergrass, Kevin Shelby, Shrenik Patel, Vern Brethour, Tom Matheney University of Minnesota: A.H. Tewfik, E. Saberinia Wisair:G. Shor, Y. Knobel, D. Yaish, S. Goldenberg, A. Krause, E. Wineberger, R. Zack, B. Blumer, Z. Rubin, D. Meshulam, A. Freund

3. No Vote Responses • MB-OFDM authors have studied the no-vote responses • Most of the technical and performance issues have already been addressed in previous presentations. • We think the most important issue is the FCC certification • Summary of presentation • MB-OFDM solution advantages • Update on the FCC Regulatory approval • Update on Guard tones issue • Miscellaneous Questions

4. Multi-band OFDMAdvantages (1) • A mature solution that has been optimized by a large number of engineers from a number of companies • Inherent robustness in all the expected multipath environments. • Excellent robustness to ISM, U-NII, and other generic narrowband interference. • Ability to comply with world-wide regulations: • Bands and tones may be turned on/off to comply with changing regulations. • Coexistence with current and future systems: • Bands and tones may be turned on/off for enhanced coexistence with the other devices.

5. Multi-band OFDMAdvantages (2) • Scalability with process: • Digital section complexity/power scales with improvements in technology nodes (Moore’s Law). • Analog section complexity/power scales slowly with technology node • Suitable for CMOS implementation • Lower cost and power solution • Antenna and pre-select filter are easier to design (can possibly use off-the-shelf components). • Low cost, low power, and CMOS integrated solution leads to: • Early market adoption!

6. Multi-band OFDM System Parameters • System parameters for mandatory and optional data rates: * Mandatory information data rate, ** Optional information data rate

7. MB-OFDM Band plan • There are 5 Band Groups: • Band group #1 is mandatory, remaining (#2 – #5) are optional. • Define 4 Time-Frequency coded Logical Channels for Band groups #1 – #4. • Define 2 Time-Frequency coded Logical Channels for Band group #5. • This yields 18 potential Logical Channels  support for 18 piconets. • Can avoid Band group #2 when interference from U-NII is present.

8. TF Codes for Multiple Access • Mapping of TF Codes and Preambles to Logical Channels in a Band Group:

9. Link Budget and Receiver Sensitivity • Assumption: Logical channel 1, AWGN, and 0 dBi gain at TX/RX antennas.

10. Multipath Performance • The distance at which the Multi-band OFDM system can achieve a PER of 8% for a 90% link success probability is tabulated below: Notes: • Simulations includes losses due to front-end filtering, clipping at the DAC, DAC precision, ADC degradation, multi-path degradation, channel estimation, carrier tracking, packet acquisition, overlap and add of 32 samples (equivalent to 60.6 ns of multi-path protection), etc. • Increase in noise power due to overlap and add is compensated by increase in transmit power (1 dB) same performance as an OFDM system using a cyclic prefix.

11. Simultaneously Operating PiconetsPerformance with TF Codes • Assumptions: • operating at a data rate of 110 Mbps with Band Group #1. • Simultaneously operating piconet (SOP) performance as a function of the multipath channel environments: • Results incorporate SIR estimation at the receiver.

12. Signal Robustness/Coexistence • Assumption: Received signal is 6 dB above sensitivity. • Value listed below are the required distance or power level needed to obtain a PER  8% for a 1024 byte packet at 110 Mb/s and a Band Group #1 device • Coexistence with 802.11a/b and Bluetooth is relatively straightforward because these bands are completely avoided with Band group #1 devices

13. Complexity • Unit manufacturing cost (selected information): • Process: CMOS 90 nm technology node in 2005. • CMOS 90 nm production will be available from all major SC foundries by early 2004. • Die size for Band Group #1 device: * Component area.

14. Power Consumption • Active CMOS power consumption

15. FCC Certification Update

16. FCC Update • As mentioned in the last meeting, both the FCC and NTIA have decided to pursue their own testing to reconcile the claims from both sides • We have had continued discussions with FCC and ITS regarding their respective test plans • We are providing information as requested to aid in understanding of MB-OFDM waveform • Merged proposal #1 companies filed with the FCC a critique of the interference study previously filed by the Coalition of C-Band Constituents (ET Dockets 98-153 and 02-380) • We have confidence in the FCC’s intention to resolve the rules interpretation issue quickly and believe they are doing everything they can to progress in a timely manner.

17. Guard Tone Update

18. Previous Definition of Guard Tones • By using a contiguous set of orthogonal carriers, the transmit spectrum will always occupy a bandwidth greater than 500 MHz. • Total of 128 tones: • 100 data tones used to transmit information (constellation: QPSK). • 12 pilot tones used for carrier and phase tracking. • 10 user-defined pilot tones. • Remaining 6 tones including DC are NULL tones. • User-defined pilot tones: • Carry no useful information. • Energy is placed on these tones to ensure that the spectrum has a bandwidth greater than 500 MHz. • Can trade the amount of energy placed on tones for relaxing analog filtering specifications. • Ultimately, the amount of energy placed on these tones is left to the implementer. Provides a level of flexibility for the implementer.

19. Motivation for Change • Merged proposal #2 proponents have shown concern over the use of Guard Tones within the MB-OFDM system. • Exact comment: Previous "No" comments have pointed out the unacceptable approach of using PN-modulated guard tones to achieve the minimum 500 MHz bandwidth required by the FCC for operation under the UWB rules. Recent public documents emphasize that this approach would both be unacceptable to the NTIA and would violate FCC general technical requirements for Part 15 operations (for details see document 04/140r2 pages).

20. New Mapping onto Guard Tones • The Guard Tones can also be used in a manner that is similar to excess BW in single-carrier systems. • This is equivalent to spreading a fraction of the data tones. • We can map the tones at the edge of the 100 data tones onto the Guard tones. • The advantage of this approach is that the information on the Guard Tones can be coherently combined with the information on the Data Tones to improve the robustness at the end of the band. • This case may become more important when we have co-channel interference. • We can also relax the filter specifications by allowing different power levels on the Guard Tones. • Relaxing the exact power requirements on these tones would allow for trade-offs in the order and complexity of the TX and RX filters.

21. Mapping Specification • Below we provide an illustration of the mapping from the edge Data Tones to the Guard Tones: • The advantage of this mapping is ease of implementation and ease of combining information from Guard Tones and Data Tones.

22. Conclusions on Guard Tone • Specified an unique mapping onto the Guard Tones that is analogous to using excess BW in single-carrier systems. • The information contained on the Guard Tones can be used to make the information carried at the edge of the band more robust, especially in the presence of co-channel interference. • This approach should address the merged proposal #2 concerns.

23. Miscellaneous Questions

24. Sculpting the Spectrum (1) • Proponents of merged proposal #2 are concerned that it may not be possible to null out tones within the preamble and protect services such as the Radio Astronomy Bands within Japan. • Exact comment: In addition, although it seems possible to turn off one or more tones in an OFDM symbol by modulating one or more tones with a "zero" value, it seems this is only feasible for the PAYLOAD portion of the MB-OFDM signal transmission. Every single MB-OFDM packet also contains a PHY preamble that is specifically defined in the time domain according to a fixed time sequence of samples. This PREAMBLE occupies the entire OFDM channel for most of the 10-microsecond preamble. Thus, it is NOT POSSIBLE to "turn off" individual tones or groups of tones in the PREAMBLE portion of each transmission. How could this approach for “sculpting” the spectrum be used to meet a regulatory requirement for lower emissions in some band (for example, a radio astronomy band, as proposed in document 03/267r5, page 7) if every packet PREAMBLE still results in emissions across the whole band?

25. Sculpting the Spectrum (2) • The PREAMBLE is composed of three sections: • A packet synchronization sequence (time-domain). • A frame synchronization sequence (time-domain). • A channel estimation sequence (frequency-domain). It is possible to zero out tones and "sculpt the spectrum" for this portion of the sequence. • For the time-domain sequences, it is also possible to "sculpt the spectrum" when needed. • One obvious approach is to pass the sequence through a filter that has notches in the appropriate locations. • The preamble sequences are typically pre-stored, so we can pre-compute the modified preambles. • Question: Is it even possible to sculpt the DS-UWB scheme without using expensive off-chip analog filters or having to rely on the overly-complex and power hungry SSA technique?

26. CMOS Solutions • DS-UWB proponents do not believe companies are developing a CMOS solution for merged proposal #1. • Exact comment: Previous statements indicated that the MB-OFDM solution was specifically designed to enable a low power all-CMOS implementation (including the RF chip)-- [see document 03/267 r5, pages 39 and 41]. Is it still the case that MB-OFDM enables an all-CMOS implementation, given that all initial implementation efforts seem to be based on SiGe process technology? • We refer the DS-UWB camp to the following web site: http://www.staccatocommunications.com • Extracted quote from web page: The company is leading industry development of the first UWB [MB-OFDM] silicon in all-CMOS to enable universal wireless connectivity of high-speed devices using available UWB spectrum.

27. Overall Summary • MB-OFDM proposal has seen significant improvements since its inception • Updated band plan gives better SOP performance with total 18 piconet channels • Document 02/268 r3 provides all the information needed to build inter-operable PHY based on this proposal. • A number of companies are at advanced stages of developing chips based on this document • FCC appears to be making good progress towards addressing the interference issue • MB-OFDM authors and supporters are actively engaged with FCC to provide all requested information and resources