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: [The ParthusCeva Ultra Wideband PHY proposal] Date Submitted: [05 May, 2003] Source: [Michael Mc Laughlin, Vincent Ashe] Company [ParthusCeva Inc.] Address [32-34 Harcourt Street, Dublin 2, Ireland.] Voice:[+353-1-402-5809], FAX: [-], E-Mail:[michael.mclaughlin@parthusceva.com] Re: [IEEE P802.15 Alternate PHY Call For Proposals. 17 Jan 2003] Abstract: [Proposal for a 802.15.3a PHY] Purpose: [To allow the Task Group to evaluate the PHY proposed] 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. Michael Mc Laughlin, ParthusCeva

2. The ParthusCeva PHYProposal Michael Mc Laughlin, ParthusCeva

3. Overview of Presentation • PHY packet contents • Coding • DSSS Coding scheme - biorthogonal coding • Ternary spreading codes • Reed Solomon FEC code • Optionally concatenated with convolutional code • Preamble • Implementation Overview • Performance • Link margin • Test results • Throughput, Multiple piconet performance • Complexity Michael Mc Laughlin, ParthusCeva

4. Packet Contents Michael Mc Laughlin, ParthusCeva

5. Symbol coding • 64 biorthogonal signals [Proakis1] • 64 signals from 32 orthogonal sequences • Ternary sequences chosen for their auto-correlation properties • Code constructed from binary Golay-Hadamard sequences Michael Mc Laughlin, ParthusCeva

6. Code comparison • Length 32 code chosen for aamf and best matching with bit rates. Michael Mc Laughlin, ParthusCeva

7. Sample rate and pulse repetition frequency • Signal bandwidth chosen is 3.85GHz to 7.7GHz • Sampling rate chosen is 7.7Ghz • 32 chips per codeword, 6 channel bits / symbol Michael Mc Laughlin, ParthusCeva

8. FEC Scheme • Concatenated code for 110 and 220Mbps • Reed Solomon outer code (235,255) • Convolutional rate 4/6 inner code • Reed Solomon code (43,63) for 490Mbps. Michael Mc Laughlin, ParthusCeva

9. FEC scheme - inner code • A 0.667 rate (rate 4/6) convolutional code was chosen for the inner code at 110 and 200 Mbps. [Proakis2] • Very low complexity 16 state code, constraint length 2, Octal generators 27, 75, 72. • Each of 16 states can transition to any other state, outputting 16 of 64 possible codewords. • Provides 3dB of gain over uncoded errors at a cost of 50% higher bit rate Michael Mc Laughlin, ParthusCeva

10. Rate 4/6 Convolutional coder + 3 bits out Map every 6 bits to one of 64 biorthogonal codewords + 1 of 64 + 2 bits in Michael Mc Laughlin, ParthusCeva

11. Preamble Sequence Michael Mc Laughlin, ParthusCeva

12. PAC properties • Because of the perfect autocorrelation property, the channel impulse response can be obtained in the receiver by correlating with the sequence and averaging the results. • Because the sequence consists of mostly 1, -1 with a small number of zeros, correlation can be economically implemented. (a length 553 PAC has 24 0’s) Michael Mc Laughlin, ParthusCeva

13. Preamble properties • Very good detect rate and false alarm probability. Pfa and Pmd < 10-4 for CM1 to CM4 test suite at 10 metres. Detected in 2s using correlator. • Different length sequences means other piconets won’t trigger detection i.e. Pfa still < 10-3 for a different piconets PACn, even at 0.3m separation. • Preamble length varies from ~5s to ~15s depending on the bit rate. Lower bitrates use longer preambles (Longer distances need more training time) Michael Mc Laughlin, ParthusCeva

14. PHY Header • The PHY header is sent at an uncoded 45Mbps rate, but with no convolutional coding. It is repeated 3 times. • The PHY header contents are the same as 802.15.3 i.e. Two octets with the Data rate, number of payload bits and scrambler seed. Michael Mc Laughlin, ParthusCeva

15. Scrambler/Descrambler • It is proposed that the PHY uses the same scrambler and descrambler as used by IEEE 802.15.3 Michael Mc Laughlin, ParthusCeva

16. Typical Tx/Rx configuration Antenna Single Chip Possible Output data at 30 - 960 Mbps Channel Matched filter (Rake Receiver) Fine/ Band Reject Filter Band Pass Filter* A/D 7.7GHz, 1 bit Viterbi Decoder Correlator Bank Switch / Hybrid LNA Descramble 8-240M symbols/sec 256 - 3800 Mchips/sec Input data at 30- 960 Mbps Band Pass Filter Chip to Pulse Generator Code Generator Band Reject Filter Convolutional encoder Scramble * Can be avoided with good LNA dynamic range Michael Mc Laughlin, ParthusCeva

17. Filter Possible RF front end configuration • Total Noise Figure = 6.6dB NF= 0.3dB (input referred) NF= 2.0dB NF= 3.5dB Fine Filter** BP Filter* LNA To Rx NF= 0.8dB Tx/Rx switch / hybrid Band reject Filter ** From Tx ** Depending on Local National or User requirements * Can be avoided with good LNA dynamic range Michael Mc Laughlin, ParthusCeva

18. Matched Filter configuration Cn 4 1 Di Cn+N Di-N Cn+1 4 1 Di-1 Di-N-1 Cn+N+1 ….. ….. 4x 4x 4x 4x 4 4 4 4 ….. 4 bit adder 4x 4x + 5 bit adder + ….. ….. Michael Mc Laughlin, ParthusCeva

19. Matched Filter configuration • Structure repeated 16 times e.g. a 500 tap filter with 4 bit coefficients would have 500 x 16 x 4 AND gates in first stage • Calculates 16 outputs in parallel, each runs at (480/mps) MHz. • e.g. 120MHz for 220Mbps • Multiplier is 4 AND gates. • First adder stage is 4 OR gates. Very little performance loss. (0dB for CM1-3, 0.23dB for CM4). • Coefficients are pre-processed to remove smallest if two clash. • mps is max pulses/sample. = 1440/(channel bit rate (Mbps)) Michael Mc Laughlin, ParthusCeva

20. Matched filter • 560 tap filter takes 135k gates or 0.82 sq mm in 0.13 standard cell CMOS • Worst case power consumption = 120mW ( at 490Mbps ), proportional to data rate. Much lower for CM1 because of fewer taps. • Matched filter re-used for correlation with training sequence during training phase • All simulations were carried out with this filter/correlator structure Michael Mc Laughlin, ParthusCeva

21. Michael Mc Laughlin, ParthusCeva

22. Distance achieved for mean packet error rate of best 90% = 8% Michael Mc Laughlin, ParthusCeva

23. Distance achieved for at worst packet error rate of best 90% = 8% Michael Mc Laughlin, ParthusCeva

24. 110 Mbps average PER Michael Mc Laughlin, ParthusCeva

25. 220 Mbps average PER Michael Mc Laughlin, ParthusCeva

26. 490 Mbps average PER Michael Mc Laughlin, ParthusCeva

27. Multiple Piconet Interferers • Tests were done according to the Multiple Piconet interference procedure outlined in the latest revision of the selection criteria (03031r11). • The distance to the receiver under test was set at 0.707 of the 90% link success probability distance. • Tests results were obtained for 1,2 and 3 interfering piconets Michael Mc Laughlin, ParthusCeva

28. Single adjacent piconet Michael Mc Laughlin, ParthusCeva

29. Two adjacent piconets Michael Mc Laughlin, ParthusCeva

30. Three adjacent piconets Michael Mc Laughlin, ParthusCeva

31. Co-channel interference • Different piconets use exactly the same data mode codes as each other. • Separation is achieved because • a) a different piconet will have a different impulse response and thus will not correlate with the matched filter which has been trained for the piconet of interest. • b) Codes won’t be synchronised • Co-channel data mode interference is exactly the same as adjacent channel interference. • Training to the preamble will be affected more markedly by co-channel interference. Difficult to simulate. Michael Mc Laughlin, ParthusCeva

32. Co existence • Out of band signals (< 3.1GHz and >10.6GHz) are always filtered out. • Any desired in band energy can be filtered out, with minimal effect on performance because the whole band is used to transfer data. • Only adverse effect is the transmit power reduction (e.g. Dropping 400MHz for 802.11a loses <0.5dB) Michael Mc Laughlin, ParthusCeva

33. Interference and susceptibility • As for co existence, out of band signal are always filtered out. • Again, any desired in band energy can be filtered out, with minimal effect on performance because the whole band is used to transfer data. • Only adverse effect is the receive power reduction (e.g. Dropping 400MHz for 802.11a loses <0.5dB), its just a part of the channel. Michael Mc Laughlin, ParthusCeva

34. Narrowband interference • Immunity to narrowband interference • With no filtering • With digital notch filter Michael Mc Laughlin, ParthusCeva

35. PHY-SAP Data Throughput • At higher bit rates, a 1024 byte frame is very short. • The channel will be stationery for more than one frame so it is possible to send multiple frames for each preamble. • T_MIFS=1μs, T_SIFS=5μs, T_PHYHDR=1.1μs,T_HCS=0.29μs, T_MACHDR=1.45μs Michael Mc Laughlin, ParthusCeva

36. Scalable solution • 55 - 980 Mbps. Gate count depends on maximum bit rate and power consumption of baseband PHY is proportional to bit rate. • 980Mbps mode works well over 2 metres, 880Mbps works even better • Short range solution possible with much smaller matched filter gate count/consumption for smaller delay spread. e.g. if poorer performance acceptable on CM4 type channels • Receiver here 3.85 - 7.7GHz. +2.5dB extra performance gain if full band used. Michael Mc Laughlin, ParthusCeva

37. Complexity - Area/Gate count, Power consumption • These figure are for a standard cell library implementation in 0.13µm CMOS Michael Mc Laughlin, ParthusCeva

38. How can it be so good? • Where does this large Performance/Cost/Power advantage come from • Compare with two proposals other proposals - TFI OFDM and Multiband • These two were chosen because of their prominence and fairly comprehensive results available Michael Mc Laughlin, ParthusCeva

39. Performance- How much better? • All similar under AWGN, i.e. 20 odd metres at 110Mbps. • 200/220/240 Mbps • ~50% farther than either TFI-OFDM or Multiband over CM1 • 92% farther than TI-OFDM and 230% farther than Multiband over CM4 • 110/120 Mbps • 22/25% farther over CM1 • 22% farther than TFI-OFDM and 75% farther than Multiband over CM4 • 480 Mbps -86% fartherthan TFI-OFDM over CM1, no CM4 or Multiband figures available. Michael Mc Laughlin, ParthusCeva

40. Performance - Why is it better? • Gap is small with no multipath at low rates, larger as the multipath increases and speed increases. • Multiband approach only gathers a small amount of multipath energy. 16ns at 120Mbps and 8ns at 240Mbps. CM4 channels have significant energy spread over 100ns • ParthusCeva PHY - has equivalent of a 230 finger rake. • Ternary codes were chosen for their multipath immunity Michael Mc Laughlin, ParthusCeva

41. Power • 110/120Mbps Rx @ 0.13 • This approach up to 145mW • Multiband approach 170-200mW • TFI - OFDM 205mW • Why so good? • Simple analog Rx section • Single bit ADC • No AGC • No mixer • No FFT in the receiver. Matched filter with 1 bit inputs. Low complexity decoders Michael Mc Laughlin, ParthusCeva

42. Cost • Comparison at 0.13µ • This approach 4.25mm2 • Multiband approach 7.3mm2 • TFI - OFDM approach 6.9mm2 • Why the difference ? • Same reasons as power, low complexity digital and analog requirements Michael Mc Laughlin, ParthusCeva

43. Summary of advantages • Ternary spreading codes • Better auto-correlation properties • Perfect PAC training sequence • Simple RF section • 1 bit A/D converter • No AGC required • No Rx mixers required • Long rake possible - near multipath immunity • 4 bit coefficients • 1 bit data • no multipliers • Cost and Power very similar to Bluetooth } Low cost Low power consumption Low Noise figure Michael Mc Laughlin, ParthusCeva

44. The ParthusCeva PHY Faster Michael Mc Laughlin, ParthusCeva

45. The ParthusCeva PHY Faster Smaller Michael Mc Laughlin, ParthusCeva

46. The ParthusCeva PHY Faster Smaller Cooler Michael Mc Laughlin, ParthusCeva

47. Backup Slides Michael Mc Laughlin, ParthusCeva

48. Self evaluation : General Criteria Michael Mc Laughlin, ParthusCeva

49. Self evaluation : PHY protocol Michael Mc Laughlin, ParthusCeva

50. Self evaluation : MAC enhancements Michael Mc Laughlin, ParthusCeva