1. 10-March-2003
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [The ParthusCeva Ultra Wideband PHY proposal]
Date Submitted: [03 Mar, 2003]
Source: [Michael Mc Laughlin, Vincent Ashe] Company [ParthusCeva Inc.]
Address [32-34 Harcourt Street, Dublin 2, Ireland.]
Voice:[ ], FAX: [-],
Re: [IEEE P Alternate PHY Call For Proposals. 17 Jan 2003]
Abstract: [Proposal for a a PHY]
Purpose: [To allow the Task Group to evaluate the PHY proposed]
Notice: This document has been prepared to assist the IEEE P 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 P
Michael Mc Laughlin, ParthusCeva

2. The ParthusCeva PHY Proposal
10-March-2003
The ParthusCeva PHY Proposal
Michael Mc Laughlin, ParthusCeva

3. Overview of Presentation
10-March-2003
Overview of Presentation
PHY packet contents
Coding
DSSS Coding scheme - biorthogonal coding
Ternary spreading codes
FEC scheme - rate 2/3 convolutional coding
Preamble
Preamble marker
Training sequence
Implementation Overview
Performance
Link margin
Test results
Michael Mc Laughlin, ParthusCeva

4. 10-March-2003
Packet Contents
Michael Mc Laughlin, ParthusCeva

5. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
10-March-2003
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
<author>, <company>

6. Ternary orthogonal sequences
10-March-2003
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

7. 10-March-2003
Good base binary set
Base set is a set of binary Golay-Hadamard sequences
Take a binary Golay complementary pair.
s116=[ ];
s216=[ ];
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

8. Creating Orthogonal Ternary Sequences
10-March-2003
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

9. Orthogonal Ternary Example
10-March-2003
Orthogonal Ternary Example
E.g
pairing 1 with 3 and 2 with 4 gives this orthogonal matrix
Michael Mc Laughlin, ParthusCeva

10. Finding good Ternary Golay Hadarmard codes
10-March-2003
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

11. 10-March-2003
Code comparison
Length 32 code chosen for aamf and best matching with bit rates.
Michael Mc Laughlin, ParthusCeva

12. Sample rate and pulse repetition frequency
10-March-2003
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

13. 10-March-2003
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

14. Convolutional coder + + + 10-March-2003 Map every 6 bits to one of 64
biorthogonal
codewords + +
2 bits in
Michael Mc Laughlin, ParthusCeva

15. Preamble The preamble used is as follows
10-March-2003
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

16. Make-up of the preamble marker PMn
10-March-2003
Make-up of the preamble marker PMn
Michael Mc Laughlin, ParthusCeva

17. 10-March-2003
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

18. Make-up of the PA sequence
10-March-2003
Make-up of the PA sequence
Michael Mc Laughlin, ParthusCeva

19. 10-March-2003
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 i.e. Two octets with the Data rate, number of payload bits and scrambler seed.
Michael Mc Laughlin, ParthusCeva

20. Scrambler/Descrambler
10-March-2003
Scrambler/Descrambler
The proposal uses the same scrambler and descrambler as used by IEEE
Michael Mc Laughlin, ParthusCeva

21. Typical Tx/Rx configuration
10-March-2003
Typical Tx/Rx configuration
Antenna
Channel Matched filter (Rake Receiver)
f) Data Decoder &
descrambler
RF front end
A/D (e.g. 7.7GHz, 1 bit)
Correlator Bank
Viterbi Decoder
Output data at Mbps
8-120M symbols/sec
Mchips/sec
Chip to Pulse Generator
Code Generator
Convolutional encoder
f) Scrambler & Data Encoder
Input data at Mbps
Michael Mc Laughlin, ParthusCeva

22. Possible RF front end configuration
10-March-2003
Possible RF front end configuration
Total Noise Figure = 7.0dB
NF= 0.2dB
(input referred)
NF= 2.0dB
NF= 4.0dB
Coarse Filter*
LNA
Fine Filter
NF= 0.8dB
To Rx
Tx/Rx switch / hybrid
Filter
From Tx
* Can be avoided with good LNA dynamic range
Michael Mc Laughlin, ParthusCeva

23. 10-March-2003
Michael Mc Laughlin, ParthusCeva

24. Packet Error Rate(PER) at 120Mbps, 10 metres
10-March-2003
Packet Error Rate(PER) at 120Mbps, 10 metres
Mean PER for best 90% = 1.8e-3
Michael Mc Laughlin, ParthusCeva

25. Packet Error Rate(PER) at 240Mbps, 4 metres
10-March-2003
Packet Error Rate(PER) at 240Mbps, 4 metres
Mean PER for best 90% = 0.0
Michael Mc Laughlin, ParthusCeva

26. PER at 240Mbps, 7 metres Mean PER for best 90% = 7.2e-3 10-March-2003
Sorted PER at 240Mbps d=7m
-0.5 -1
8% PER
Log10(PER)
-1.5 -2
-2.5 50
100
150
200
250
300
350
400
Channel
Michael Mc Laughlin, ParthusCeva

27. PER at 240Mbps, 6.5 metres Mean PER for best 90% = 2.0e-3
10-March-2003
PER at 240Mbps, 6.5 metres
Mean PER for best 90% = 2.0e-3
Michael Mc Laughlin, ParthusCeva

28. PER at 480Mbps, 3 metres Mean PER for best 90% = 7.9e-3 10-March-2003
Michael Mc Laughlin, ParthusCeva

29. } Summary of advantages Ternary spreading codes
10-March-2003
Summary of advantages
Ternary spreading codes
Better auto-correlation properties
Perfect PACF training sequence
1 bit A/D converter
No AGC required
No mixer required
Long matched filter possible
4 bit coefficients
1 bit data
no multipliers }
Low cost
Low power consumption
Michael Mc Laughlin, ParthusCeva

30. 10-March-2003
References
[Proakis1] John G. Proakis, Digital Communications 2nd edition. McGraw Hill. pp
[Proakis2] John G. Proakis, Digital Communications 2nd edition. McGraw Hill. pp
[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 , Oct
[Høholdt et al] Tom Høholdt and Jørn Justesen, “Ternary sequences with Perfect Periodic Autocorrelation”, IEEE Transactions on information theory.
Michael Mc Laughlin, ParthusCeva