September 2004
doc.: IEEE 802.15-04-0492-00-004a
Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: PHY Recommendation—Ternary AM DSB-SC with partial response pulse shaping
Date Submitted: 10 September 2004
Source: Chandos A. Rypinski
Company: consultant
Address: Tiburon, CA 94920 USA
Voice: +1 415 435 0642 FAX: none E-Mail: chanryp@sbcglobal.net
Re: TG4A Call for contributions, Jason Ellis, August 2004
Abstract: The proposed PHY is ternary amplitude modulation transmitted double sideband suppressed
carrier with partial response pulse shaping. The demodulation process does not use or need
synchronization of a local oscillator with the transmitter. The side lobes are at least 30 dB down at the
defined channel bandwidth continuing to decrease down to 50 dB.
Purpose: This proposal is a candidate for entry into the down-selection process for the TG4A]
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.
Submission
Slide 1
Chandos A. Rypinski, Consultant
September 2004
doc.: IEEE 802.15-04-0492-00-004a
PHY Recommendation—
Ternary AM DSB-SC
(with partial response pulse shaping)
Chandos A. Rypinski, consultant
with Bob Ritter and John Armanini
MicroTech Specialist
Submission
Slide 2
Chandos A. Rypinski, Consultant
September 2004
doc.: IEEE 802.15-04-0492-00-004a
Summary of Desired Properties
An uncommon digital modulation technique is recommended for
short-reach, scalable data rate personal area as an
alternative to widely used GMSK, BPSK, DPSK and OQPSK
modulations. The targeted applications are those requiring a
combination of properties which include:
high like-signal interference resistance to enable extensive
frequency reuse over a large area,
low sidelobe levels to enable better use of adjacent channels and
the flexibility to trade off channel coding schemes and occupied
bandwidth for the best fit to the specific application
Submission
Slide 3
Chandos A. Rypinski, Consultant
September 2004
doc.: IEEE 802.15-04-0492-00-004a
Summary of Proposal
The recommended baseband modulation is amplitude
modulated ternary (three amplitude levels) DSB-SC
(double-sideband suppressed carrier) with partial
response type pulse shaping.
The specific unit-pulse shape (now referred to as
“Sym-pulse”) used provides minimized use of low
frequencies with zero dc component and low levels of
side lobes.
Submission
Slide 4
Chandos A. Rypinski, Consultant
September 2004
doc.: IEEE 802.15-04-0492-00-004a
Advantage Summary A
Zero dc and reduced low frequency energy density
below 10% of the high edge frequency of the power
density spectrum enables baseband amplification with
video rather than dc amplifiers.
Independence of rf phase/frequency at demodulation:
1) great tolerance to motion of the user station
2) decreased susceptibility to phase reversal errors
with frequency dependent time domain fades.
Low adjacent channel and second channel emissions
are the result of using the right pulse shape in the first
place, rather than filtering a high side lobe signal.
Submission
Slide 5
Chandos A. Rypinski, Consultant
September 2004
doc.: IEEE 802.15-04-0492-00-004a
Advantage Summary B
Copper pairs can transport the baseband waveform
large distances without equalization.
Overhead time used for acquisition is greatly reduced
by the absence of the need for rf synchronization.
Twice the average power allowed for BPSK may be
used with the specified channel coding. Half the bits
are 0's transmitted at zero amplitude creating a 50%
duty cycle.
Submission
Slide 6
Chandos A. Rypinski, Consultant
September 2004
doc.: IEEE 802.15-04-0492-00-004a
Property Summary for Ternary DSB-SC
Feasible data rates:
10 Kbps to 32 Mbps
Spectrum zero’s:
Zero’s at 0, 0.8 x bit-rate, 1.0 x bit-rate
Occupied bandwidth: @ -10 dB
@ -20 dB
@ -30 dB
Acquisition time:
Submission
0.16 to 1.28 x bit-rate
0.08 to 1.4 x bit-rate
0.04 to 1.5 x bit rate
zero time for rf synchronization
120 bits for AGC setting, bit clock
acquisition and start delimiting
Slide 7
Chandos A. Rypinski, Consultant
September 2004
doc.: IEEE 802.15-04-0492-00-004a
The Unit Pulse
Duobinary Pulse, Scaled Duobinary Pulse and First Derivative
1
The unit pulse defines the spectral
characteristics. A number of
concatenated, overlapping pulse
make up the bit stream. The
composite stream has about the same
spectrum as the unit pulse.
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
dav
0
0.1
0.2
The length of the space between zero
crossings at the center is equal to one
bit. The unit pulse may be upright or
inverted or zero.
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0
40
80
120
160
200
240
280
320
btv
Submission
Slide 8
Chandos A. Rypinski, Consultant
X2b  Vb10.5  Vb11.9  Vb12.98  Vb13.82  Vb14.46  Vb15.13  Vb16 .1  Vb17 .16  Vb18.1
Xb  V2004
Vb7.91
 Vb8802.15-04-0492-00-004a
.6  X2b
September
IEEE
b .09  Vb1 .16  Vb2 .12  Vb3 .1  Vb4 .42  Vb5 .78  Vb6 .98  doc.:
X
The Serial Data Stream at Video Baseband
Xd  aa ( V  LU) d2
2
Vd
0
2
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95 100 105 110 115 120 125 130
70
75
80
85
90
95 100 105 110 115 120 125 130
d12
20
10
Xd
0
10
20
0
5
10
15
20
25
30
35
40
45
50
55
60
65
d
Upper: 130 bits of psuedo random source data
Lower: Corresponding Sym-pulse video waveform
Submission
Slide 9
Chandos A. Rypinski, Consultant
September 2004
doc.: IEEE 802.15-04-0492-00-004a
“Eye diagram”
1.2
1
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1
-1.2
The “Eye” diagram shows all transition trajectories between
consecutive states. There are two eyes and two decision
thresholds (one after squaring) for the Sym-pulse modulation.
Submission
Slide 10
Chandos A. Rypinski, Consultant
M  a
Averaging using Moving Average "FIR" Filter
N  22004
LU
September
m  0  M  1
n  a  N
hm 
doc.: IEEE 802.15-04-0492-00-004a
1
M
M1
FIR moving average Filter
Power Density
Data Burst

  Spectrum for
qn 
hm( n  m  0) ( n  m  N  1) Enm
m0
0
This PSD is for the previously
shown video data stream
operating at 25 Mbps. This is
a mathematical simulation
20
qn 16 40
60
80
0
5
10
15
20
25
30
35
40
45
50
n 125
a
The X-axis is in steps of 5 MHz. The
Y-axiz is in steps of 20 dB
2 4
The first non-zero null is at 20.5 MHz and the second at 25-26 MHz
Submission
Slide 11
Chandos A. Rypinski, Consultant
September 2004
doc.: IEEE 802.15-04-0492-00-004a
Power Density Spectrum
from Analyzer Screen Capture
This figure is the DSB radio signal at 5.25 GHz. The X-axis
grid is in steps of 10 MHz. The Y-axis is is steps of 10 dB.
Submission
Slide 12
Chandos A. Rypinski, Consultant
September 2004
doc.: IEEE 802.15-04-0492-00-004a
Power Density Spectrum from System Simulation
DSB-SC at 25 Mbps
X-axis: 20 MHz/div
Y-axis: 10 dB/div
CF: 5.250 GHz
Submission
Slide 13
Chandos A. Rypinski, Consultant
September 2004
doc.: IEEE 802.15-04-0492-00-004a
Radio Implementation Block Diagram
5.25 GHz Signal Frequency
Video baseband data processing
376-424 MHz IF (DSB) amplifiers
Automatic Gain Control
BPF
LNA
A
Signal =
0.400 GHz
Antenna ports
BPF
A
PA
376-424
MHz
BPF
4.850
GHz
BSL
LPF
+
BSL
LPF
T
T
Transmit level control
peak
detector
^ 2
R
^ 2
Reference
threshold
A
LPF
strobe in
C
Data
out
analog
amplitude
out
bit clock
generator
synchronized
/2
Data
clock
BSL
LPF
T out
BPF
A
+
BSL
LPF
T AGC
5 GHz Synthesizer
10 MHz master
frequency reference
BPF
preamble
memory
2X LO in
Transmit signal Processor
A
Video
Data
Stream
800 MHz Synthesizer
PROM
bit clock
waveform &
clock pulse
generator
Data
in
FIFO in and
FIFO out
Data
in
incoming data buffer
This radio operates
5.25
GHz withCarrier
a firstAM
IFData
of 400
MHz. ItDiagram
is double
5.25 GHzatDSB
Suppressed
Radio--Block
Mbps
in 48 MHz bandwidth
sideband suppressed carrier.30The
modulator-demodulator-detector
function
is shown in the central blue box. The data rate is up to 32 Mbps in 50 MHz.
C. A. Rypinski
File: AM DSBSCchip_e3u
Submission
Slide 14
Chandos A. Rypinski, Consultant
September 2004
doc.: IEEE 802.15-04-0492-00-004a
The Value of Phase/frequency
Independent AM Modulation
A typical room coverage appears to contain coverage holes due to cancellation of
the predominant path rays. When a cancellation fade is traversed in time
frequency or space, the rf phase is usually reversed between entering and leaving.
While increased transmitter power will moderately decrease the hole size, it rarely
will make the hole disappear.
An rf phase reversal can shake loose a PLL which will then take many bit times to
recover causing a “hit” type data error. A similar difficult can exist in a
mathematical de-rotator.
When a cancellation null is encountered, there may be a substantial recovery time
if PLL loops are use to recover virtual carrier (e.g., Costas loop). This difficult can
be overcome by using differential QPSK where the phase reference for the current
pulse is the preceding pulse. Since the reference has the same noise as the signal
there is a small loss S/N threshold, but many have thought it worthwhile for the
reduction in size of hit errors.
Submission
Slide 15
Chandos A. Rypinski, Consultant
September 2004
doc.: IEEE 802.15-04-0492-00-004a
Frequency Independent Amplitude Demodulation (1)
The amplitude detector is based on using an vector (I-Q)
demodulator which may be at an intermediate or signal
frequency. The output processing is based on the identity:
sin²(θ)+cos²(θ) = 1
The I and Q outputs are separately squared and the two
results summed to obtain a phase-independent measure of the
signal amplitude. The squaring operation yields a single
positive output for either phase in the source signal, and it
provides an amplitude indication proportional to signal
power and independent of phase angle.
Submission
Slide 16
Chandos A. Rypinski, Consultant
September 2004
doc.: IEEE 802.15-04-0492-00-004a
Frequency Independent Amplitude Demodulation (2)
The data demodulator assumes use of an approximate AGC which is set
at the start of the burst preamble and refreshed during the message. A
second forward acting level compensator sets the threshold in relation to
the peak signal level. The threshold is set at about 70% of the reference
level for a comparator device which at sampling time determines the level
to be above or below threshold.
There is an integrate-and-dump circuit which sums the areas of the central
half of the incoming bit-pulse. The integration capacitor is sampled at the
end of the charge interval and it is discharged during the non-integrate
interval.
The block diagram of this type of demodulator appears in the radio block
diagram of Figure 8. This block diagram has been simulated end-toantenna-path-antenna-to-end in same simulator as used for Figure 5.
Submission
Slide 17
Chandos A. Rypinski, Consultant
September 2004
doc.: IEEE 802.15-04-0492-00-004a
Closing Summary (1)
We propose that the TG4A committee accept Ternary AM DSB-SC with
partial response pulse shaping as a candidate for the opening PHY layer
selection.
Anyone can propose, but only a majority constituency can select. Any
opening recommendation is likely to be substantially modified before it
is acceptable for incorporation in the standards document.
If selected, we will do everything necessary to enable a multi-vendor
environment according to IEEE Standards Rules.
We plan to build a small number of technology demonstrator’s which
are now being designed. These could be available for independent
verification of properties in December 2004 or soon after.
Submission
Slide 18
Chandos A. Rypinski, Consultant
September 2004
doc.: IEEE 802.15-04-0492-00-004a
Closing Summary (2)
This proposal offers a competent function, implemented with
smallest and simplest circuit function. It is one of the best for:

transmitter power utilization

resistance to like and foreign signal interference

minimal out-of-band side lobe levels

resistance to errors from multipath including moving reflectors
(one of only a few modulations with this property)

accurate transmission without forward error correction

fast and simple clock acquisition
Please join us in supporting the choice of this modulation
Submission
Slide 19
Chandos A. Rypinski, Consultant