Enhanced Notch Depth with Modified Adjacent Frequency Coding

1. Modified Adjacent Frequency Coding For Increased Notch Depth under DAA/Spectral SculptingKevin A. Shelby, Johann Chiang, Dr. Jim LansfordAlereon Inc.CrownCom MykonosJune 2006

2. Outline • Objectives • Regulatory Outlook • System Overview • System Design Considerations • Simulation Results • Closing Remarks WiMedia Confidential

3. Objectives • Extend adjacent frequency coding to include some form of multi-carrier modulation: • Reuse antipodal signaling aimed at canceling sidelobe contributions in adjacent carriers; • Introduce multi-carrier modulation to minimize the impact on the existing WiMedia PHY Specification: • Preserve the existing time/frequency spreading characteristics in order to maintain system performance in the presence of a variety of channel impairments, SOP interference most notably; • Preserve the existing tone mapping to minimize the impact on the interleave and cyclic shift structures. WiMedia Confidential

4. DAA Requirement Postponed in Europe until June 30, 2010 Band Group 1 Band Group 2 Band Group 3 Band Group 4 Band Group 5 1 2 3 4 5 6 7 8 10 11 12 14 9 13 Increased Rolloff DAA Required DAA Required Current Regulatory Outlook WiMedia Confidential

5. Adjacent Sidelobe Contributions • AFC leverages the observation that sidelobe contributions in adjacent tones are similar in amplitude: WiMedia Confidential

6. Sidelobe Cancellation • The achievable notch depth can be increased by canceling adjacent sidelobe contributions: WiMedia Confidential

7. Existing DCM Mechanism • Dual Carrier Modulation as originally conceived can be described in terms of a linear transformation, M, as follows: • Where the indices {a,b,c,d} represent a mapping from the interleaved transmit bitstream, • and M={mij}; i,j=[1:2] constitutes a linear mapping of tones in the transmit OFDM symbol. WiMedia Confidential

8. Modified AFC • Building directly on the original AFC proposal, a linear mapping resembling that employed by DCM can be identified, aimed at canceling mutual interference in adjacent subcarriers: • Where ck=xk +jyk corresponds to the output of the symbol mapper, QPSK or DCM encoded, depending on the selected data rate.* *The extent to which M-AFC can be applied at rates above 200Mb/s is still under investigation. WiMedia Confidential

9. Preamble DACs Baseband Transmitter Guard Pilots Coding/ Puncturing Zero DC Scrambler Interleaver Symbol Mapper ()* Tone Nulling IFFT 2X Analog Filters Add Zero Suffix P/S WiMedia Confidential

10. System Design Considerations WiMedia Confidential

11. Achievable Notch Depth WiMedia Confidential

12. TX Constellation(=8/16) WiMedia Confidential

13. Equalizer Output DeMapper Output DeSpread Output RX Constellation WiMedia Confidential

14. System Simulation Simulation results were compiled using the following system configuration: • WiMedia compliant 1.0 PHY • Mandatory rates (53.3-200Mb/s)[1] • M-AFC, = 0.5 • ~20MHz tone notching (3.6-3.8GHz) • Incumbent service passive during link tests [1]The applicability of M-AFC to higher data rates is still under investigation WiMedia Confidential

15. DAA Spectral Scultping Simple Tone Notching Modified AFC WiMedia Confidential

16. Link Performance WiMedia Confidential

17. Closing Remarks • M-AFC applies a linear transformation at the symbol mapper output leaving tone assignment and existing interleaver structure unchanged; • Resembling DCM, M-AFC achieves antipodal signaling without sacrificing the time/frequency spreading present in the existing spec; • The resulting notch depth approaches that demonstrated with the original AFC, less ~5dB once considerations affecting link performance are taken into account; • The rate of OOB rolloff also increases similarly to the original AFC proposal over that without antipodal signaling. WiMedia Confidential