Transcript 10-March-2003 doc.: IEEE 802.15 - Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [The ParthusCeva Ultra Wideband.

10-March-2003
doc.: IEEE 802.15 - <03123r1>
Project: IEEE P802.15 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:[+353-1-402-5809], FAX: [-], E-Mail:[[email protected]]
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.
PHY proposal
Slide 1 of 30
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
The ParthusCeva PHY
Proposal
PHY proposal
Slide 2 of 30
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
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
PHY proposal
Slide 3 of 30
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
Packet Contents
PMn
Preamble
marker
PHY proposal
PAn
Preamble
Channel
Identification
PHY Header
15 Mbps
biorthogonal coding
Slide 4 of 30
Payload Data
30 - 480 Mbps
biorthogonal coding
& convolutional coding
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
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
PHY proposal
Slide 5 of 30
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
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.
PHY proposal
Slide 6 of 30
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
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
PHY proposal
Slide 7 of 30
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
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
PHY proposal
Slide 8 of 30
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
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
•
•
•
•
PHY proposal
2
2
0
0
0
0
2
-2
0 2
0 -2
2 0
2 0
Slide 9 of 30
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
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
PHY proposal
Slide 10 of 30
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
Code comparison
Code
Length mean aamf min aamf
Best Ternary Golay Hadamard
40
5.90
4.54
Best Ternary Golay Hadamard
32
5.52
3.26
Best Binary Golay Hadamard
32
4.43
2.21
Best Binary Golay Hadamard
64
4.72
3.50
Orthogonal Gold
32
2.37
1.29
Orthogonal Gold
64
2.11
1.06
• Length 32 code chosen for aamf and best matching
with bit rates.
PHY proposal
Slide 11 of 30
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
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)
PRF
60Mbps
120Mbps
240Mbps
480Mbps
0.48 Gpps
0.96 Gpps
1.92 Gpps
3.86Gpps
30 Msym/sec
60 Msym/sec
120 Msym/sec
8
4
2
Symbol rate 15 Msym/sec
Samples
/pulse
PHY proposal
16
Slide 12 of 30
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
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
PHY proposal
Slide 13 of 30
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
Convolutional coder
+
+
Map every 6 bits to
one of 64
biorthogonal
codewords
+
2 bits in
PHY proposal
Slide 14 of 30
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
Preamble
•
The preamble used is as follows
PMn
PAn
•
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.
PHY proposal
Slide 15 of 30
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
Make-up of the preamble marker PMn
LCCn
Siln
LCCn
Siln
LCCn
……..
LCCn
Siln
LCCn
LCCn is one of four 64 bit binary sequences with good auto correlation
properties and low cross correlation with the other three. Each channel
uses a different sequence. It is sent 16 times at a pulse rate of 7.7GHz.
LCCn is the same sequence inverted. The transition to this from LCC
provides a time marker for the rest of the packet. It is sent 4 times.
Siln is a silent period . The length is slightly different for each channel
but is approximately 33ns. This reduces the cross correlation between
multiple sequences and reduces spectral peaks.
PHY proposal
Slide 16 of 30
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
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:
•
•
•
•
--+-++--+-++---++--+++--++--+--+-++++------+-++++++-++++++-+-+-+
-+++++++-++--+++++--+----++-++--++++-+---+++--+-+-+-+--+-++-+-++
---+----+------++++-+++-+---+-+-+-+--+++-+--++--++--+-++-+--+--+
++-++---++++-+-++-+++-+++-++-++-++-+---+-+-+---+---+++++++-++---
These codes
Mean aamf
Min aamf
Max cross correlation
PHY proposal
7.4
6.6
0.23
Slide 17 of 30
Best 4 of 63 chip
Gold codes
3.1
2.9
0.30
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
Make-up of the PA sequence
PACFn
PACFn
PACFn
……..
PACFn
PACFn
PA consists of up to 144 repetitions of PACF.
PACFn is a ternary sequence with perfect periodic autocorrelation properties. It comes
from a family of such sequences discovered by Valery Ipatov [Ipatov],[Høholdt et al].
There are many sequences in this family, e.g. lengths 381,553,651,757,871,993. The
length 553 one was chosen as a compromise between complexity and the length of
impulse response that can be resolved. There are four such length 553 sequences used, a
different one for each channel. i.e. each piconet operates with a different length 553
PACF.
PHY proposal
Slide 18 of 30
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
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.
PHY proposal
Slide 19 of 30
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
Scrambler/Descrambler
• The proposal uses the same scrambler and
descrambler as used by IEEE 802.15.3
PHY proposal
Slide 20 of 30
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
Typical Tx/Rx configuration
Antenna
RF front
end
A/D (e.g.
7.7GHz, 1 bit)
Channel
Matched filter
(Rake Receiver)
256 - 3800
Mchips/sec
Chip to Pulse
Generator
PHY proposal
Code Generator
Slide 21 of 30
Correlator
Bank
Viterbi
Decoder
f) Data
Decoder &
descrambler
Output data at
30 - 480 Mbps
8-120M
symbols/sec
Convolutional
encoder
f) Scrambler &
Data Encoder
Input data at
30- 480 Mbps
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
Possible RF front end configuration
• Total Noise Figure = 7.0dB
NF= 2.0dB
NF= 4.0dB
Coarse Filter*
Fine Filter
NF= 0.8dB
LN
A
Tx/Rx
switch /
hybrid
NF= 0.2dB
(input referred)
To Rx
Filter
From Tx
* Can be
avoided with
good LNA
dynamic range
PHY proposal
Slide 22 of 30
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
Link Budget
Parameter
Value
Value
Value
Throughput (Rb)
120 Mb/s
240 Mb/s
480 Mb/s
Tx power (PT ) (Allows -6.9dBm
for 1.5dB margin)
0 dBi
Tx antenna gain ( GT )
-6.9dBm
-6.9dBm
0 dBi
0 dBi
Centre frequency
5.48GHz
5.48GHz
5.48GHz
Loss at 1 metres
47.1dB
47.1dB
47.1dB
Loss at d metres
20 dB (10m)
12 dB (4m)
9.5 dB (3m)
Rx antenna gain
0 dBi
0 dBi
0 dBi
Rx power
-74dBm
-66.1dBm
-63.6dBm
Noise power/bit
-93.2dBm
-90.2dBm
-87.2dBm
Rx Noise Figure
7dB
7dB
7dB
Noise power/bit
-86.2dBm
-83.2dBm
-80.2dBm
Min Eb/N01 (S)
4.6dB
4.8dB
5.3dB
Imp. Loss (I)
2.2dB
2.4dB
2.5dB
Link Margin
4.7dB
9.9dB
8.8dB
2
Rx Sens. Level
-78.7dBm
-76.0dBm
-69.0dBm
Notes:
1 - Minimum Eb/No for 8% PER with “ideal” ADC and Matched Filter
2 - Average implementation loss for 1 bit ADC and 553 tap matched filter with 4 bit coefficients
PHY proposal
Slide 23 of 30
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
Packet Error Rate(PER) at 120Mbps, 10 metres
•
Mean PER for best 90% = 1.8e-3
Sorted PER at 120Mbps d=10m
0
Log10(PER)
-0.5
-1
-1.5
-2
-2.5
PHY proposal
0
50
100
150
200
Channel
250
Slide 24 of 30
300
350
400
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
Packet Error Rate(PER) at 240Mbps, 4 metres
•
Mean PER for best 90% = 0.0
Sorted PER at 240Mbps d=4m
0
Log10(PER)
-0.5
-1
-1.5
-2
-2.5
PHY proposal
0
50
100
150
200
Channel
250
Slide 25 of 30
300
350
400
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
PER at 240Mbps, 7 metres
•
Mean PER for best 90% = 7.2e-3
Sorted PER at 240Mbps d=7m
0
Log10(PER)
-0.5
-1
8% PER
-1.5
-2
-2.5
PHY proposal
0
50
100
150
200
Channel
250
Slide 26 of 30
300
350
400
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
PER at 240Mbps, 6.5 metres
•
Mean PER for best 90% = 2.0e-3
Sorted PER at 240Mbps d=6.5m
0
Log10(PER)
-0.5
-1
-1.5
-2
-2.5
PHY proposal
0
50
100
150
200
Channel
250
Slide 27 of 30
300
350
400
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
PER at 480Mbps, 3 metres
•
Mean PER for best 90% = 7.9e-3
Sorted PER at 480Mbps d=3m
0
Log10(PER)
-0.5
-1
-1.5
-2
-2.5
PHY proposal
0
50
100
150
200
Channel
250
Slide 28 of 30
300
350
400
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
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
PHY proposal
Slide 29 of 30
Michael Mc Laughlin, ParthusCeva
10-March-2003
doc.: IEEE 802.15 - <03123r1>
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.
PHY proposal
Slide 30 of 30
Michael Mc Laughlin, ParthusCeva