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Project: IEEE P802.11b Working Group for Wireless Local Area Networks (WLANs)

Project: IEEE P802.11b Working Group for Wireless Local Area Networks (WLANs) Submission Title: [Summary of SG Proposal to TGg] Date Submitted: [ 12 March 2001 ] Source: [ T. O’Farrell, L.E. Aguado & C. Caldwell] Company [Supergold Communication Ltd. ]

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Project: IEEE P802.11b Working Group for Wireless Local Area Networks (WLANs)

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  1. Project: IEEE P802.11b Working Group for Wireless Local Area Networks (WLANs) Submission Title: [Summary of SG Proposal to TGg] Date Submitted:[ 12 March 2001 ] Source: [ T. O’Farrell, L.E. Aguado & C. Caldwell] Company [Supergold Communication Ltd. ] Address [ 2-3 Sandyford Village, Sandyford, Dublin 18, Ireland ] Voice:[ +44 113 233 2052 ], FAX: [ +44 113 2332032 ], E-Mail:[ tim.ofarrell@supergold.com ] Re: [ Physical layer modulation proposal for the Higher Rate Extension to 802.11b Standard] Abstract: [ This contribution is a summary presentation of Supergold’s MBCK proposal for the Higher Rate Extension to 802.11b Standard] Purpose: [ Proposal for the Higher Rate Extension to 802.11b Standard] Notice: This document has been prepared to assist the IEEE P802.11. 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 P802.11. O'Farrell, Aguado & Caldwell, Supergold Comm. Ltd.

  2. Outline of the Presentation • Comparison Criteria • Performance Evaluation • MBCK Attributes • Soft Decision Decoding • Conclusions O'Farrell, Aguado & Caldwell, Supergold Comm. Ltd.

  3. Comparison Criteria • The following new results have been included in documents 336r48G and 1017r28G • MBCK Performance with an DFE equaliser • Timing off-set performance • Jamming test completed for PER=10-2 O'Farrell, Aguado & Caldwell, Supergold Comm. Ltd.

  4. Comparison Criteria – Cont. • Anomalies addressed • PA back-off figures • ISI only multipath performance at 25 ns rms delay spread O'Farrell, Aguado & Caldwell, Supergold Comm. Ltd.

  5. Performance Evaluation Note: performance of reference systems from IEEE 802.11-01/064r1, “Comparison of 802.11g Proposals” PER vs Eb/No (1000B) O'Farrell, Aguado & Caldwell, Supergold Comm. Ltd.

  6. Performance Evaluation Note: performance of reference systems from IEEE 802.11-01/064r1, “Comparison of 802.11g Proposals” PER vs SNR (1000B) O'Farrell, Aguado & Caldwell, Supergold Comm. Ltd.

  7. Performance Evaluation Note: performance of reference systems from IEEE 802.11-01/064r1, “Comparison of 802.11g Proposals” PER vs SNR (1000B) O'Farrell, Aguado & Caldwell, Supergold Comm. Ltd.

  8. M-ary Bi-Code Keying • Supergold’s solution is a concatenated coding scheme consisting of: • Inner MBCK 64 state quaternary block code • Maps to 16 QAM constellation and spans 4 symbols. • Outer Reed Solomon (63,k) code • k=41 for 22 Mb/s and k=57 for 30 Mb/s O'Farrell, Aguado & Caldwell, Supergold Comm. Ltd.

  9. 1 DATA IN 8 xI I OUT Select1 of 64Sequences 1 6 c d RSEncoder 1 xQ Q OUT 32 Sequences + Complements 1 rI Rx I IN 1 Greatest PeakDetector 32-Correlator Bank 6 c’ y RSDecoder 1 rQ DATAOUT Rx Q IN 64-ary Bi-Code Keying • MBCK-RS Encoding Chain O'Farrell, Aguado & Caldwell, Supergold Comm. Ltd.

  10. MBCK Attributes • Thorough evaluation of MBCK according to the comparison criteria completed: (ref. 336r48G and 1017r28G). • Good coding gain • PA non-linearity effects are constrained for back-offs > 4 dB • MBCK waveform ameanable to equalisation by all the key equalisation techniques O'Farrell, Aguado & Caldwell, Supergold Comm. Ltd.

  11. MBCK Attributes - Cont • Supports 22 and 30 Mb/s modes • Tolerant to 10% rms timing jitter • Tolerant to 4o rms phase noise O'Farrell, Aguado & Caldwell, Supergold Comm. Ltd.

  12. MBCK Attributes - Cont • MBCK is a robust coding scheme that meets the TGg comparision criteria • Low complexity code (7 kgates for MBCK and 7 kgates for Reed Solomon Code) • Works with the same radio as 802.11b • Low cost solution • Readily implementable giving short time to market (RTL code for MBCK available) O'Farrell, Aguado & Caldwell, Supergold Comm. Ltd.

  13. Soft Decision Decoding with MBCK • A soft metric can be readily obtained from the MBCK signal set using common symbol-to-bit mapping techniques • Allows the use of binary convolutional codes (bcc) with MBCK; two codes investigated • Rate 2/3 Punctured [133 171] – p133171 • Rate 2/3 bcc (64 state trellis code) O'Farrell, Aguado & Caldwell, Supergold Comm. Ltd.

  14. Soft Decision Decoding with MBCK • Rate 2/3 code supports 22 and 29 Mb/s rates • 22 Mb/s mode uses 64-ary BCK • 29 Mb/s mode uses 256-ary BCK • Both MBCK codes span 4 symbols • No change in clocks, radio or baseband processor. O'Farrell, Aguado & Caldwell, Supergold Comm. Ltd.

  15. Soft Decision Decoding with MBCK BER vs. Eb/N0 in the AWGN for bcc O'Farrell, Aguado & Caldwell, Supergold Comm. Ltd.

  16. Soft Decision & MBCK – 22 Mb/s BER vs. SNR for MBCK in the AWGN for p133171 and bcc (100 B/Pk) BER vs. SNR for MBCK in the AWGN for p133171 and bcc (100 B/Pk) O'Farrell, Aguado & Caldwell, Supergold Comm. Ltd.

  17. Soft Decision & MBCK – 29 Mb/s BER vs. SNR for MBCK in the AWGN for p133171 and bcc (100 B/Pk) O'Farrell, Aguado & Caldwell, Supergold Comm. Ltd.

  18. Soft Decision & MBCK – Summary • 22 Mb/s mode gives 1.25 dB coding gain over RS at 10-2 PER • 29 Mb/s mode gives 2.25 dB coding gain over RS at 10-2 PER • 64 state code offers enhanced PER performance for reasonable complexity O'Farrell, Aguado & Caldwell, Supergold Comm. Ltd.

  19. MBCK-BCC Encoding Chain 1 DATA IN xI 8 I OUT Select1 of 64Sequences 1 6 c d BCCEncoder 1 xQ Q OUT 32 Sequences + Complements 1 rI Rx I IN 1 Soft Decision Metric 6 c’ y ViterbiDecoder 1 rQ DATAOUT Rx Q IN M-ary Bi-Code Keying O'Farrell, Aguado & Caldwell, Supergold Comm. Ltd.

  20. I/Q Tx Waveform Quaternary Code LUT Data LUT 20-20 1 3-1-3 3-1-3 1 1 3 1 3 3-1 3-1 Greatest Peak Detector & Sign 1 3 1 3 3-1 3-1 1 3-1-3 3-1-3 1 -1-3-1-3 -3 1-3 1 -1-3 1 3 -3 1 3-1 I&D I&D I&D I&D 0 0 0 0 0 1 0 1 0 0 1 1 1 0 0 1 0 1 1 1 0 1 1 1 00 000100 000 100 1 3 1 3-1-3-1-3 00 00 Tx Function Rx Function 8-ary BCK Example using Length 4 Quanternary Codes O'Farrell, Aguado & Caldwell, Supergold Comm. Ltd.

  21. Conclusions • MBCK is a low complexity code that • Meets the WLAN robustness criteria • Is a mature concept based on MBOK • Uses same radio as 802.11b • Can be used with all equaliser types • Can use Hard & Soft Decision FEC • Is an inexpensive solution for WLANs • A road map exists to achieve even higher data rates with MBCK O'Farrell, Aguado & Caldwell, Supergold Comm. Ltd.

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