Transcript Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANS) Submission Title: [TG3a Performance Considerations in UWB Multi-Band] Date Submitted: [May.

Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANS)
Submission Title: [TG3a Performance Considerations in UWB Multi-Band]
Date Submitted: [May 5, 2003]
Source: Naiel Askar Ph.D., Susan Lin, Ph.D., Jason Ellis, General AtomicsPhotonics Division, Advanced Wireless Group, 10240 Flanders Ct, San Diego,
CA 92121-2901, Voice +1 (858) 457-8700], Fax [+1 (858) 457-8740], E-mail
[[email protected], [email protected] , [email protected]}
Re: [Technical contribution]
Abstract: [This technical contribution looks at 2 approaches to UWB MultiBands and compares them]
Purpose: [Technical contribution to compare 2 approaches to UWB Multi-Bands]
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
or organization. The material in this document is subject to change in form and
content after further study. The contributor reserves 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.
May 2003
doc.: IEEE 802.15-03/208r0
TG3a Performance Considerations
in UWB Multi-Band
Naiel Askar, Ph.D. ([email protected])
Susan Lin, Ph.D. ([email protected])
Jason Ellis ([email protected])
www.ga.com/uwb
Submission
Slide 2
General Atomics – Naiel Askar
May 2003
doc.: IEEE 802.15-03/208r0
Outline
• Definition of UWB Multi-Bands
• Comparison of 2 Specific UWB Multi-Band Approaches
– Fixed Sequencing of Bands
– Variable Sequencing of Bands
– Comparison Criteria
• Modulation
• Energy Capture
• Pulse Repetition Frequency (PRF)
• Hardware Architecture
• Channelization
• Why we support a fixed sequencing approach!
Submission
Slide 3
General Atomics – Naiel Askar
May 2003
doc.: IEEE 802.15-03/208r0
UWB Multi-Band Defined
• The Multi-Band Coalition* defines UWB multi-bands as
– Partitioning 7,500 MHz of unlicensed UWB spectrum into
multiple bands (3-16 bands) occupying between 500 – 700 MHz
Example UWB Frequency Bands in a Mutiband Approach
0
0.8
-2
0.6
-4
0.4
-6
Amplitude (dB)
Amplitude
A multiband UWB Symbol
1
0.2
0
-0.2
-8
-10
-12
-0.4
-14
-0.6
-16
-0.8
-18
-1
0
2
4
6
8
Time (ns)
10
12
14
Time
16
-20
3
3.5
4
4.5
Frequency(GHz)
5
5.5
6
Frequency
* www.uwbmultiband.org
Submission
Slide 4
General Atomics – Naiel Askar
May 2003
doc.: IEEE 802.15-03/208r0
Comparison of Modulations
•
Typically for Fixed Sequencing; BPSK, QPSK and variations of PPM is
used on multiple bands for modulation
•
Spectral KeyingTM modulation allows varying the sequence of the
bands, in addition to potential usage of BPSK or QPSK on each band
– Allows encoding more information per band
– Lower PRF is possible
– High data rates achieved using fewer bands
• Because the set of allowable symbols increases with the factorial of the
number of bands
f6
f5
f4
f3
f2
f1
Fixed Sequencing
Variable Sequencing
(Spectral KeyingTM)
Submission
Slide 5
General Atomics – Naiel Askar
May 2003
doc.: IEEE 802.15-03/208r0
Energy Capture is Primarily a Function of Bandwidth
• Energy capture is important in severe multipath channels
• Determined by
– Bandwidth of transmitted pulse
– Number of Rake arms
Impact of Receive Bandwidth on Total Received Energy for CM1
1
0
-1
-2
-3
-4
-5
3 GHz BW
2 GHz BW
1 GHz BW
0.5 GHz
0.25 GHz BW
.125 GHz BW
-6
-7
-8
0
2
4
6
8
No. of Rake Arms
CM1
Submission
10
Received Power Relative to Total Available Power
Received Power Relative to Total Available Power
• Energy capture is almost independent of modulation
• Bandwidth of 500-700 MHz per band allows capture for a good
percentage of energy without severe fading
Impact of Receive Bandwidth on Total Received Energy for CM4
0
-2
-4
-6
-8
3 GHz BW
2 GHz BW
1 GHz BW
0.5 GHz
0.25 GHz BW
.125 GHz BW
-10
-12
-14
0
2
4
6
8
10
No. of Rake Arms
CM4
Slide 6
General Atomics – Naiel Askar
May 2003
doc.: IEEE 802.15-03/208r0
Multi-Band Approach Enables Variable PRF
•
Spectral KeyingTM achieves slightly lower PRF than Fixed Sequencing
•
Low PRF
– Reduces collisions between successive pulses of same frequency
– Enables off periods between transmissions which allow collection of more
energy with a serial Rake receiver
•
The variable PRF concept allows the optimization of the transmitted
waveform to channel properties and required range
Two Repetitions at Full PRF
1
0
-1
1.41
26.5 ns
One Repetition at Half PRF
0
-1.41
53 ns
Submission
Slide 7
General Atomics – Naiel Askar
May 2003
doc.: IEEE 802.15-03/208r0
Example Multi-Band Implementations
Serial arm receiver
– Suitable for fixed
sequence Multi-Band
solutions
– Can still collect multiple
rays from the same band
Parallel arm receiver
– Suitable for any
Multi-Band solution
– Allows collection of more
signal energy
– Needs ability to turn off
unused components
Submission
Slide 8
General Atomics – Naiel Askar
May 2003
doc.: IEEE 802.15-03/208r0
How a Single Arm Receiver Collects Energy
• Off period between multiple chips can be utilized to
collect more energy in all Multi-Band solutions by
implementing the variable PRF concept
• Improvements of range equivalent to 2-4 dB are
obtained in some channels
transm m ited signal
one sam ple receiver
f1
f4
f7
f 3
f 6
f1
sam pling clock
two sam ple receiver
f1
sam pling clock
Submission
General Atomics – Naiel Askar
Slide 9
f3
May 2003
doc.: IEEE 802.15-03/208r0
Multipath Performance Results Show Comparable Results
GA Tentative Multiband
Performance Results
SK Simulation Results
SK Best 90 Channels
Min Range (m)
Mean Range (m)
8.3
10.7
9.3
10.5
8.3
9.4
6.6
7.9
CM1
CM2
CM3
CM4
CM1
CM2
CM3
CM4
Min Range (m)
8.8
7.0
5.5
3.9
Mean Range (m)
10.8
9.0
7.4
6.2
Multiband Performance Results (Wisair Presentation)
Reference CM
CM1
CM2
CM3
CM4
Submission
90% Reliability
One Rx Path
9.8
7.3
7.1
6.1
Slide 10
90% Mean
One Rx Path
11.3
8.6
8.3
7.3
90% Reliability
Two Rx Paths
11.0
9.3
8.3
7.7
90% Mean
Two Rx Paths
12.5
10.7
9.4
8.6
General Atomics – Naiel Askar
May 2003
doc.: IEEE 802.15-03/208r0
Multiple Access for Multi-Band Schemes
• Multi-Bands have many options for multiple access
– Fixed Sequencing
• Time Frequency Codes
• FDM
• CDMA
• Time Interleaved
– Variable Sequencing (SK)
• FDM
• Time Interleaved
Submission
Slide 11
General Atomics – Naiel Askar
May 2003
doc.: IEEE 802.15-03/208r0
Multiple Access Performance Results
SK Multiple Access Results
Interference
AWGN N=1
CM1/6-10 N=1
CM3/6-10 N=1
CM4/6-10 N=1
AWGN N=2
AWGN N=3
SK Relative distance for 8% PER
User Channel
AWGN
CM1/1-5 CM2/1-5 CM3/1-5
0.6
0.8
0.8
0.9
0.5
0.7
0.7
0.7
0.4
0.6
0.6
0.6
0.4
0.6
0.6
0.6
1.0
1.4
1.3
1.4
1.3
1.7
1.6
1.8
CM4/1-5
1.0
0.8
0.7
0.7
1.5
2.0
Wisair Multiple Access Results
Reference CM
CM1
CM2
CM3
CM4
Submission
dint/dref
1 interferer
0.58
0.68
0.92
1.12
Slide 12
dint/dref
2 interferers
0.65
0.79
1.01
1.44
dint/dref
3 interferers
0.78
1.00
1.19
1.63
General Atomics – Naiel Askar
May 2003
doc.: IEEE 802.15-03/208r0
Conclusions – Fixed vs. Variable Sequencing
• Multi-Band Coalition has performed extensive performance
comparisons for both approaches
• General Atomics’ conclusion is that the 2 approaches can both
yield excellent results
• We are supporting the Fixed Sequencing approach for 802.15.3a
because
– It is a more open approach, which is more amenable to
including further concepts
– It supports early merge activities
• We are actively contributing to a merged UWB Multi-Band proposal
• We will continue to develop variable sequence technologies such
as Spectral KeyingTM for applications outside of 802.15.3a
Submission
Slide 13
General Atomics – Naiel Askar