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 ParthusCevaUltra Wideband PHY proposal] Date Submitted: [03 Mar, 2003] Source: [Michael Mc Laughlin, Vincent Ashe] Company [ParthusCeva Inc.] Address [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. Packet Contents Michael Mc Laughlin, ParthusCeva

4. The coding scheme • 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

5. Ternary orthogonal sequences • From any base set of 32 orthogonal binary signals, can generate 32C16 sets of 32 orthogonal ternary sequences. • Generate by adding and subtracting any 16 pairs. • Generally, if the base set has good correlation properties, so will a generated set. Michael Mc Laughlin, ParthusCeva

6. Good base binary set • Base set is a set of binary Golay-Hadamard sequences • Take a binary Golay complementary pair. • s116=[1 1 1 1 1 1 -1 -1 -1 1 1 -1 -1 1 -1 1]; • s216=[1 1 1 1 -1 -1 1 1 -1 1 1 -1 1 -1 1 -1]; • if A=circulant(s116) and B=circulant(s216) • and G32= A B BT -AT • then G32 is a Hadamard matrix. [Seberry] • This type has particularly good correlation properties[Seberry] • Detector can use the Fast Hadamard Transform Michael Mc Laughlin, ParthusCeva

7. Creating Orthogonal Ternary Sequences • Take a matrix of binary orthogonal sequences • Add any two rows to get a ternary sequence. • Sum of any other two rows is orthogonal to this. • Continue till all rows used. • Repeat but subtracting instead of adding Michael Mc Laughlin, ParthusCeva

8. Orthogonal Ternary Example • E.g. 1 1 1 1 • 1 -1 1 -1 • 1 -1 -1 1 • 1 1 -1 -1 • pairing 1 with 3 and 2 with 4 gives this orthogonal matrix • 2 0 0 2 • 2 0 0 -2 • 0 2 2 0 • 0 -2 2 0 Michael Mc Laughlin, ParthusCeva

9. Finding good Ternary Golay Hadarmard codes • Large superset of orthogonal sequence sets to test • Define aperiodic autocorrelation merit factor (aamf) as the ratio of the peak power of the autocorrelation function to the RMS of the offpeak values divided by the length of the code. • Random walk used to find set with best aamf Michael Mc Laughlin, ParthusCeva

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

11. Sample rate and pulse repetition frequency • Signal bandwidth chosen is 3.8GHz to 7.7GHz • Sampling rate chosen is 7.7Ghz • 32 chips per codeword, 4 bits / symbol (6 bits less 2 for convolutional code) Michael Mc Laughlin, ParthusCeva

12. FEC scheme • A rate 2/3 convolutional code was chosen for the FEC. [Proakis2] • 64 state code, constraint length 3, Octal generators 27, 75, 72. • Each of 64 states can transition to 16 new states. All 64 possible codewords mapped to all possible 64 output codewords • Provides 3dB of gain over uncoded errors at a cost of 50% higher bit rate Michael Mc Laughlin, ParthusCeva

13. Convolutional coder + Map every 6 bits to one of 64 bi-orthogonal codewords + + 2 bits in Michael Mc Laughlin, ParthusCeva

14. Preamble • The preamble used is as follows • PMn is a sequence used to mark the preamble for channel n and provide timing information. • PAn is a sequence used by the receiver to calculate the channel impulse response. Michael Mc Laughlin, ParthusCeva

15. Make-up of the preamble marker PMn Michael Mc Laughlin, ParthusCeva

16. LCC properties • The LCCs used have very good cross and auto correlation properties. (e.g. much better Auto correlation and better cross correlation than Gold codes, better ACF than Kasami codes) and were generated by a random walk. These codes are: • --+-++--+-++---++--+++--++--+--+-++++------+-++++++-++++++-+-+-+ • -+++++++-++--+++++--+----++-++--++++-+---+++--+-+-+-+--+-++-+-++ • ---+----+------++++-+++-+---+-+-+-+--+++-+--++--++--+-++-+--+--+ • ++-++---++++-+-++-+++-+++-++-++-++-+---+-+-+---+---+++++++-++--- Michael Mc Laughlin, ParthusCeva

17. Make-up of the PA sequence Michael Mc Laughlin, ParthusCeva

18. 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

19. Scrambler/Descrambler • The proposal uses the same scrambler and descrambler as used by IEEE 802.15.3 Michael Mc Laughlin, ParthusCeva

20. Typical Tx/Rx configuration Antenna Channel Matched filter (Rake Receiver) f) Data Decoder & descrambler A/D (e.g. 7.7GHz, 1 bit) Correlator Bank Viterbi Decoder Output data at 30 - 480 Mbps RF front end 8-120M symbols/sec 256 - 3800 Mchips/sec Chip to Pulse Generator Code Generator Convolutional encoder f) Scrambler & Data Encoder Input data at 30- 480 Mbps Michael Mc Laughlin, ParthusCeva

21. NF= 0.2dB NF= 4.0dB NF= 2.0dB LNA NF= 0.8dB Crude Filter Fine Filter Filter Tx/Rx switch / hybrid From Tx Possible RF front end configuration • Total Noise Figure = 7.0dB Michael Mc Laughlin, ParthusCeva

22. Michael Mc Laughlin, ParthusCeva

23. Packet Error Rate(PER) at 120Mbps, 10 metres • Mean PER for best 90% = 1.8e-3 Michael Mc Laughlin, ParthusCeva

24. Packet Error Rate(PER) at 240Mbps, 4 metres • Mean PER for best 90% = 0.0 Michael Mc Laughlin, ParthusCeva

25. PER at 240Mbps, 7 metres • Mean PER for best 90% = 7.2e-3 Sorted PER at 240Mbps d=7m 0 -0.5 -1 8% PER Log10(PER) -1.5 -2 -2.5 0 50 100 150 200 250 300 350 400 Channel Michael Mc Laughlin, ParthusCeva

26. PER at 240Mbps, 6.5 metres • Mean PER for best 90% = 2.0e-3 Michael Mc Laughlin, ParthusCeva

27. PER at 480Mbps, 3 metres • Mean PER for best 90% = 7.9e-3 Michael Mc Laughlin, ParthusCeva

28. References • [Proakis1] John G. Proakis, Digital Communications 2nd edition. McGraw Hill. pp 224-225. • [Proakis2] John G. Proakis, Digital Communications 2nd edition. McGraw Hill. pp 466-470. • [Seberry et al] J. Seberry, B.J. Wysocki and T.A. Wysocki, Golay Sequences for DS CDMA Applications,University of Wollongong • [Ipatov] V. P. Ipatov,“Ternary sequences with ideal autocorrelation properties”Radio Eng. Electron. Phys., vol. 24, pp. 75-79, Oct. 1979. • [Høholdt et al] Tom Høholdt and Jørn Justesen, “Ternary sequences with Perfect Periodic Autocorrelation”, IEEE Transactions on information theory. Michael Mc Laughlin, ParthusCeva