March 3, 2003
doc.: IEEE 802.15-<03147r0>
Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [Multicarrier-UWB]
Date Submitted: [3 March 2003]
Source: [Ahmed H Tewfik] Company [University of Minnesota]
Address [Dept. of Electrical and Computer Engineering, Room 4-174 EECS Bldg.,Minneapolis, MN
55455]
Voice:[612-625-6024], FAX: [612-625-4583], E-Mail:[tewfik@ece.umn.edu]
Re: [n/a]
Response to a Call for Contributions Task Group 3a Call For Intent and Proposals, November 2002,
updated January 2003, 02371r0P802-15_SG3a-5_Criteria.doc
Abstract: [We propose a multi-carrier UWB system for WPAN communications. We describe system
design issues and proposed transmitter and receiver structures. We also provide a self-evaluation of the
proposed system.]
Purpose: [For consideration by 802.15.3a task group.]
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
Tewfik/Saberinia, U. of MN
March 3, 2003
doc.: IEEE 802.15-<03147r0>
Multicarrier-UWB
A. H. Tewfik and E. Saberinia
University of Minnesota
Submission
Slide 2
Tewfik/Saberinia, U. of MN
March 3, 2003
doc.: IEEE 802.15-<03147r0>
Overview
•
•
•
•
•
Unified view of UWB
Multicarrier-UWB
Proposed system
N-tone sigma-delta modulators
Self-evaluation
Submission
Slide 3
Tewfik/Saberinia, U. of MN
March 3, 2003
doc.: IEEE 802.15-<03147r0>
Unified View of UWB
• General form
x(t )   br (t ) p(t  rTp )
r
• Special cases
– TM-UWB
– DS-UWB

 b ( t )u
N 1
p(t )   s(t  nT  cnTc )
k 
k
Tp
x
(t  kTp )

 p(t  rT )
n 0
r 
N 1
p(t )   cn s(t  nT )
n 0
N 1
– MC-UWB
Info. signal
p(t )   s(t  nT )e
j
pulse train
2 cn t
Tc
uTp(t)
n 0
Tp
Submission
Slide 4
Tewfik/Saberinia, U. of MN
p
March 3, 2003
doc.: IEEE 802.15-<03147r0>
Unified View of UWB
Info. signal

 b ( t )u
k 
k
Tp
x
x
(t  kTp )
N 1
  s(t  nT  c T
r
n 0
n c
N 1
 rTp )
pulse train
  u
r
n 0
n T
(t  nT  rTp )
FH or DS
Spreading sequence
• Advantageous to view p(t) as:
p(t)= [pulse train]x[spreading sequence]
Submission
Slide 5
Tewfik/Saberinia, U. of MN
March 3, 2003
doc.: IEEE 802.15-<03147r0>
Desirable Attributes
p (t ) 
Baseband signal
replicas around
Fourier components at

 s(t  nT )
Shaping due
to s(t)
n 
pulse train
fk= k/T
x
Info. signal
u(t)

1/NT
 ak u(t  kNT )
k 
NT
1/T
• Replication in time and frequency domains needed for
reliable communications
• Poor spectral use
– Spectral gaps
– Spectral shaping due to S(f)
Submission
Slide 6
Tewfik/Saberinia, U. of MN
March 3, 2003
doc.: IEEE 802.15-<03147r0>
Desirable Attributes
p (t ) 
Fill the gaps
between spectral
lines at fk= k/T

 s(t  nT )
Shaping due
to s(t)
n 
pulse train
x
Info. signal
u(t)
 N 1
j 2 lt / NT 
a
e

 u(t  kNT )


k ,l

k   l 0

1/NT
NT
1/T
• Fill the gaps between the spectral lines
Submission
Slide 7
Tewfik/Saberinia, U. of MN
March 3, 2003
doc.: IEEE 802.15-<03147r0>
Desirable Attributes
K
 b p(t  rT )e
r
k 1
r
k
j 2 kf 0 ( t  rT p )
p
L 1
h ( t )    l ( t   l )
p ( t ) e
 j 2 mf 0t
rm ( i )
l 0
MC-UWB
Matched filter
channel
L 1
rm ( i )   bm  l e j 2 mf0 ( i  l ) X p  i   l ,0 
l 0
N 1 L 1
   bkl e j 2 mf0 ( i  l ) X p  i   l ,( m  k ) f 0 
k 0 l 0
k m
 wm ( i ).
Submission
Slide 8
Tewfik/Saberinia, U. of MN
March 3, 2003
doc.: IEEE 802.15-<03147r0>
Desirable Attributes
• Ambiguity function of p(t)
C p ( , f ) 


p(t ) p* (t   )e  j 2 ft dt,

• Would like:
Cp(,f)  0
except for the origin (,f) =(0,0)
Submission
Slide 9
Tewfik/Saberinia, U. of MN
March 3, 2003
doc.: IEEE 802.15-<03147r0>
Multicarrier UWB
• Elemental signal
N 1
p(t )   s(t  nT )e
j
2 c ( n ) t
Tc
,
n 0
• c(n): Costas’ sequence
• Time resolution: Tc/N
• Frequency resolution:
1/NT
Submission
Slide 10
Tewfik/Saberinia, U. of MN
March 3, 2003
doc.: IEEE 802.15-<03147r0>
Multicarrier UWB
• Advantages
– Good time and frequency resolution
– Time resolution decoupled from
• elementary pulse duration
• inter-pulse separation
 More flexibility for design
Submission
Slide 11
Tewfik/Saberinia, U. of MN
March 3, 2003
doc.: IEEE 802.15-<03147r0>
Design Approach
• Select elementary pulse duration based
on peak power and pulse length
limitations and desired sidelobe
behavior in frequency domain
• Select inter-pulse separation and
number of pulse based on channel
spread and average power limitation
• Select TC to fill available bandwidth
Submission
Slide 12
Tewfik/Saberinia, U. of MN
March 3, 2003
doc.: IEEE 802.15-<03147r0>
Proposed System
MC-UWB signal
data
TCM-QAM
10 tone IFFT
1 bit
D/A
x
• System parameters:
– N=30, T=9nsec,
Ts=1nsec, Tc=4.5nsec
– 8 subcarriers with TCM
32-ary QAM
– 2 Pilots
Submission
Slide 13
Modulation:
Carrier + FH spreading
Tewfik/Saberinia, U. of MN
March 3, 2003
doc.: IEEE 802.15-<03147r0>
Transmitter
Re( )
TCMQAM
FH
c(n)
I
FF
T
1 bit
D/A
X
VCO
S
/2
Im( )
Submission
N-Tone
S D
N-Tone
S D
Slide 14
1 bit
D/A
X
Tewfik/Saberinia, U. of MN
March 3, 2003
doc.: IEEE 802.15-<03147r0>
Proposed System
Demodulator
1 bit
A/D
10 tone FFT
Costas
sequence
modulated
filterbank
Pilot
correlation
Decision
AGC
S
data
Submission
Slide 15
Tewfik/Saberinia, U. of MN
March 3, 2003
doc.: IEEE 802.15-<03147r0>
Traditional Sigma Delta
X(n)
+
+
1
1  z 1
1 bit
quantizer
-
y(n)
z 1
Y ( z 1 )  X ( z 1 )  (1  z 1 ) E ( z 1 ) .
quantization
error
Submission
Slide 16
Tewfik/Saberinia, U. of MN
March 3, 2003
doc.: IEEE 802.15-<03147r0>
Traditional Sigma Delta D/A
X(t)
+
oversample
+
1 bit
quantizer
1
1  z 1
-
Lowpass
Filtering and
downsampling
Multibit
X(n)
z 1
Analog switched capacitor implementation
Submission
Slide 17
Tewfik/Saberinia, U. of MN
March 3, 2003
doc.: IEEE 802.15-<03147r0>
Traditional Sigma Delta D/A
X(n)
+
L
upsample
+
1
1  z 1
1 bit
quantizer
1 bit
D/A
Analog
Lowpass
Filtering
-
X(t)
z 1
• Higher order SD preferred:
– Better noise shaping
– Eliminate spuriousSlidetones
Submission
18
Tewfik/Saberinia, U. of MN
March 3, 2003
doc.: IEEE 802.15-<03147r0>
N Tone Sigma Delta
X(n)
(e.g., output of
N point IFFT)
+
+
1
1  zN
1 bit
quantizer
-
y(n)
zN
Y ( z 1 )  X ( z 1 )  (1  z  N ) E ( z  N ).
zeros at
e j2 k/N
Submission
Slide 19
quantization
error
Tewfik/Saberinia, U. of MN
March 3, 2003
doc.: IEEE 802.15-<03147r0>
N Tone Sigma Delta
600
2.5
2
500
1.5
1
Amplitude
Output of filters
400
0.5
0
300
-0.5
200
-1
-1.5
100
-2
-2.5
0
0
100
200
300
Time
400
500
600
0.05
0.1
0.15
0.2
0.25
0.3
Fractional frequency offset
0.35
0.4
0.45
0.5
“Instantaneous” Frequency spectrum
Filter outputs
Submission
0
Slide 20
Tewfik/Saberinia, U. of MN
March 3, 2003
doc.: IEEE 802.15-<03147r0>
N Tone Sigma Delta
600
500
Amplitude
400
300
200
100
0
Submission
0
0.05
0.1
0.15
0.2
0.25
0.3
Fractional frequency offset
0.35
0.4
Average Frequency
Slide 21 spectrum
0.45
0.5
Tewfik/Saberinia, U. of MN
March 3, 2003
doc.: IEEE 802.15-<03147r0>
Multiple Piconets
• Simultaneous operation achieved by
proper selection of:
– Pulse train p(t)
• Costas sequence c(n)
• Time hopping
– Carrier frequencies
Submission
Slide 22
Tewfik/Saberinia, U. of MN
March 3, 2003
doc.: IEEE 802.15-<03147r0>
Self-Evaluation
Parameter
Value
Value
Value
Throughput (Rb)
> 110 Mb/s
> 200 Mb/s
Average Tx power ( PT )
dBm
dBm
> 480 Mb/s
(optional)
dBm
Tx antenna gain (GT )
0 dBi
0 dBi
0 dBi
Hz
Hz
DB
dB
f 
f min f max : geometric center frequency of Hz
waveform ( f min and f max are the -10 dB edges
'
c
of the waveform spectrum)
'
Path loss at 1 meter ( L1  20 log 10 ( 4f c / c) )
c  3  10 m/s
dB
8
Path loss at d m (
L2  20 log 10 ( d )
)
G
Rx antenna gain ( R )
P  PT  GT  G R  L1  L2
Rx power ( R
(dB))
dBm
DBm
dBm
Average
noise
N  174
 10power
* log 10per
( Rbbit
)
(
)
dBm
DBm
dBm
Rx Noise Figure
N F 1 Referred to the Antenna
Terminal (
)
P NN
dB
DB
dB
dBm
DBm
dBm
dB
DB
dB
ImplementationMLoss
 PR(I) PN  S  I
dB
DB
dB
Link Margin (
dB
DB
dB
dBm
DBm
dBm
N
Average noise power per bit (
F
)
Minimum E b/N0 (S)
2
)
Proposed Min. Rx Sensitivity Level3
Submission
20 dB at d=10 12 dB at presenter
meters
d=4 meters specified
0 dBi
0 dBi
0 dBi
Slide 23
Tewfik/Saberinia, U. of MN
March 3, 2003
doc.: IEEE 802.15-<03147r0>
Self-Evaluation
CRITERIA
Unit Manufacturing
Complexity (UMC)
REF.
IMPORTANCE
LEVEL
3.1
B
Interference And
Susceptibility
3.2.2
A
Coexistence
3.2.3
A
Manufacturability
3.3.1
A
Time To Market
3.3.2
A
Regulatory Impact
3.3.3
A
Scalability (i.e. Payload Bit
3.4
A
3.5
C
PROPOSER RESPONSE
Signal Robustness
Technical Feasibility
Rate/Data Throughput,
Channelization – physical or coded,
Complexity, Range, Frequencies of
Operation, Bandwidth of Operation,
Power Consumption)
Location Awareness
Submission
Slide 24
Tewfik/Saberinia, U. of MN
March 3, 2003
doc.: IEEE 802.15-<03147r0>
Self-Evaluation
CRITERIA
Size And Form Factor
REF.
IMPORTANCE
LEVEL
5.1
B
PROPOSER RESPONSE
PHY-SAP Payload Bit Rate & Data Throughput
Submission
Payload Bit Rate
5.2.1
A
PHY-SAP Data Throughput
5.2.2
A
Simultaneously Operating
Piconets
5.3
A
Signal Acquisition
5.4
A
Link Budget
5.5
A
Sensitivity
5.6
A
Multi-Path Immunity
5.7
A
Power Management Modes
5.8
B
Power Consumption
5.9
A
Antenna Practicality
5.10
B
Slide 25
Tewfik/Saberinia, U. of MN
March 3, 2003
doc.: IEEE 802.15-<03147r0>
Self-Evaluation
December, 2002
CRITERIA
MAC Enhancements And
Modifications
Submission
IEEE P802.15-03/031r5
REF.
IMPORTANCE
LEVEL
4.1.
C
Slide 26
PROPOSER RESPONSE
Tewfik/Saberinia, U. of MN
March 3, 2003
doc.: IEEE 802.15-<03147r0>
Conclusion
• Multi-carrier UWB offers ability to use
traditional baseband modulation
schemes and achieve desired
performance
• Implementation simplified by use of Ntone sigma-delta modulators
Submission
Slide 27
Tewfik/Saberinia, U. of MN