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PBCC-22

PBCC-22. Chris Heegard, Ph.D., Sean Coffey, Ph.D., Anuj Batra, Ph.D., Srikanth Gummadi and Matthew Shoemake, Ph.D. Home and Wireless Networking. Texas Instruments 141 Stony Circle, Suite 130 Santa Rosa California 95401 (707) 521-3060, heegard@ti.com. Outline. History

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PBCC-22

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  1. PBCC-22 Chris Heegard, Ph.D., Sean Coffey, Ph.D., Anuj Batra, Ph.D.,Srikanth Gummadi and Matthew Shoemake, Ph.D.Home and Wireless Networking Texas Instruments 141 Stony Circle, Suite 130 Santa Rosa California 95401 (707) 521-3060,heegard@ti.com Chris Heegard, Texas Instruments

  2. Outline • History • Discovery of a New Code • PBCC-22 Properties and Performance • Conclusion Chris Heegard, Texas Instruments

  3. Short History of PBCC • Alantro Communications incorporated, August 1997 Blending the Theory of Information with the Art of Silicon • PBCC-11 introduced in IEEE 802.11 • 64 State Binary Convolutional Code + Signal Scrambler • Introduced in March 1998 meeting • Adapted as “High Performance” option • Although it provided a more robust solution, +3dB C.G., it was deemed “too complex” • Time to market was a major factor in selection of CCK • Harris semiconductor had a working MBOK chip Chris Heegard, Texas Instruments

  4. Movitation for Higher Performance Chris Heegard, Texas Instruments

  5. History (cont) • PBCC-22 developed beginning in summer of 1998 • Constraints • Interoperability with IEEE 802.11b networks • Translate coding gain advantage to “double the data rate” • 22 Mbps • Compatibility with IEEE 802.11b radios • 8-PSK, 11 MHz symbol rate, short preamble • Operate in the same environment as CCK-11 • 64 state code --->> 256 state code • A good engineering solution: cost versus performance • Satisfy FCC Requirements Chris Heegard, Texas Instruments

  6. Discovery of a New Code • Problem: Find optimal • (k=2, n = 3) 256 state code matched to 8PSK • Solution discovered in January 1999 • The new code has many interesting features • Optimal Distance Spectrum for 8-PSK • Optimal Free Distance in many scenarios • 8-PSK, Digital-8PSK • Hamming distance (Binary coding) • Underboeck 8-way partition (Trellis Coded QAM) Chris Heegard, Texas Instruments

  7. Packet Binary Convolutional Coding • Combines Binary Convolutional Coding with Codeword Scrambling • PBCC-22Rate k=2, n=3 encoder • 256 state • Digital-8PSK modulation • Dfree^2/Es = 704/98 = 8.6 dB • Reference: 16QAM+Interleaved (k=1,n=2) 64 state BCC • Dfree^2/Es = 40/10 = 6.0 dB (-2.6 dB) Chris Heegard, Texas Instruments

  8. PBCC Components Chris Heegard, Texas Instruments

  9. BCC Encoder for 22Mbps • PBCC-22: Chris Heegard, Texas Instruments

  10. The “s” Sequence • A length 256 sequence generated from a length 16 sequence • [c0,c1,…,c15] = [0011001110001011] • Periodically extended for >256 Chris Heegard, Texas Instruments

  11. Digital 8-PSK Chris Heegard, Texas Instruments

  12. Cumulative Distribution with Upper Bound 50 40 30 Number of States: 256 Average Number G: 21 2 12 20 10 25 12 10 0 350 360 370 380 390 400 Distance Cumulative Distribution with Upper Bound 600 500 400 Number of States: 256 Average Number G: 21 2 12 300 10 25 12 200 100 0 350 400 450 500 Distance Distance Bound Chris Heegard, Texas Instruments

  13. Distance Spectrum with Cumulative Distribution 8 7 6 5 Number of States: 256 G: 21 2 12 Average Number 10 25 12 4 3 2 1 0 350 360 370 380 390 400 Distance Average Distance Spectrum Chris Heegard, Texas Instruments

  14. AWGN Performance Chris Heegard, Texas Instruments

  15. Chris Heegard, Texas Instruments

  16. Chris Heegard, Texas Instruments

  17. Conclusions • PBCC is an innovative new code that solves a real problem • Backward compatible with IEEE 802.11b standard • Backward compatible with radio and regulatory requirements • “Doubles the Data Rate” in the same environment • Patent pending Chris Heegard, Texas Instruments

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