January 2005 Molisch et al., Preliminary Proposal doc.: 15-05-0005-00-004a Submiss ion Project: IEEE P802.15 Working Group for Wireless Personal Area Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Networks (WPANs) Submission Title: Mitsubishi-electrics-time-hopping-impulse-radio- standards-presentation Date Submitted: November 15, 2004 Source: Andreas F. Molisch et al., Mitsubishi Electric Research Laboratories Address MERL, 201 Broadway Cambridge, MA, 02139, USA Voice: +1 617 621 7558, FAX: +1 617 621 7550 , E-Mail: [email protected]Re: [Response to Call for Proposals] Abstract: Purpose: [Proposing a PHY-layer interface for standardization by 802.15.4a] 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.
Transcript
January 2005
Molisch et al., Preliminary Proposal
doc.: 15-05-0005-00-004a
Submission
Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: Mitsubishi-electrics-time-hopping-impulse-radio-standards-presentation Date Submitted: November 15, 2004Source: Andreas F. Molisch et al., Mitsubishi Electric Research LaboratoriesAddress MERL, 201 Broadway Cambridge, MA, 02139, USA Voice: +1 617 621 7558, FAX: +1 617 621 7550 , E-Mail: [email protected]
Re: [Response to Call for Proposals]
Abstract:
Purpose: [Proposing a PHY-layer interface for standardization by 802.15.4a]
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.
January 2005
Molisch et al., Preliminary Proposal
doc.: 15-05-0005-00-004a
Submission
Ultra WideBand
Mitsubishi Electric Proposal
Impulse Radio
A. F. Molisch, Z. Sahinoglu, P. Orlik, J. ZhangMitsubishi Electric Research Lab
M. Z. WinMassachusetts Institute of Technology
S. GeziciPrinceton University
Y. G. LiPrinceton University
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Molisch et al., Preliminary Proposal
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Submission
Contents
– Proposal overview – Goals
– Impulse radio basics
– Proposed hybrid modulation
– Physical-layer details
– Ranging
– Simulation results
– Summary and conclusions
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Molisch et al., Preliminary Proposal
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Submission
Goals• Provide a system that can work with different
modulation and detection methodsAllows trade-offs among transmitter and receiver
complexity/cost/performance Works with a variety of signaling (modulation) methods
and pulse shapesEnables different receiver structures: coherent,
differential, incoherent
• Specific proposal built on novel technologies for impulse radio transceivers
• Share ideas with other 4a members in the hope of working together.
January 2005
Molisch et al., Preliminary Proposal
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Submission
Impulse Radio Basics
January 2005
Molisch et al., Preliminary Proposal
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Submission
Time Hopping Impulse Radio (TH-IR)
Ts
Tc
Tf
+1
-1
• Each symbol represented by sequence of very short pulses
• Each user uses different sequence (Multiple access capability)
•Bandwidth mostly determined by pulse shape
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Molisch et al., Preliminary Proposal
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Submission
TH-IR Coherent RAKE Receiver
Rake ReceiverFinger Np
AGC
Rake ReceiverFinger 2
Rake ReceiverFinger 1
SummerConvolutional Decoder Data
Sink
Optimum receiver for multipath channels
January 2005
Molisch et al., Preliminary Proposal
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Submission
Transmitted Reference
Ts
TcTf
Td
+1
-1
•First pulse serves as template for estimating channel distortions
•Second pulse carries information
•Drawback: Waste of 3dB energy on reference pulses
• Different applications require different performance
• Vendors want to differentiate themselves• 802.15.4 already has different device types
• We provide proposal that allows trade-offs among complexity/capability/cost and performance– Enables simple receivers without penalizing more complex
•Addition of Matched Filter prior to delay and correlate operations improves output signal to noise ratio and reduces noise-noise cross terms
SNR of decision statistic
January 2005
Molisch et al., Preliminary Proposal
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Submission
Proposed RAKE -- Coherent Receiver
Rake ReceiverFinger Np
Demultiplexer Rake ReceiverFinger 2
Rake ReceiverFinger 1
Summer
Channel Estimation
Convolutional Decoder Data
Sink
Sequence Detector
• Addition of Sequence Detector – Proposed modulation may be viewed as having memory of length 2• Main component of Rake finger: pulse generator• A/D converter: 3-bit, operating at symbol rate• No adjustable delay elements required
January 2005
Molisch et al., Preliminary Proposal
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Submission
Channel Estimation
• Swept delay correlator
• Principle: estimating only one channel sample per symbol. Similar concept as STDCC channel sounder of Cox (1973).
• Sampler, AD converter operating at SYMBOL rate
• Requires longer training sequence
• Two-step procedure for estimating coefficients:– With lower accuracy: estimate at which taps energy is significant
– With higher accuracy: determine tap weights
• “Silence periods”: for estimation of interference
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Molisch et al., Preliminary Proposal
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Submission
Multiple Access
• Multiple access:– Combination of pulse-position-hopping and polarity
hopping for multiple access
– More degrees of freedom for design of good hopping sequence than pure pulse-position-hopping
– Short or long hopping sequences possible
• Long hopping sequence == period of sequence > Number of frames in a symbol.
– In TR: also increased interference from reference pulse to data pulse
– Depends on
• Solution: adaptive frame duration– Feed back delay spread and interference to transmitter
– Depending on those parameters, TX chooses frame duration
January 2005
Molisch et al., Preliminary Proposal
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Submission
PER Performance Coherent Reception
608 Kbps, Td = 20ns, 20 Frames per symbol
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Molisch et al., Preliminary Proposal
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Submission
PER Performance Differential Reception
608 Kbps, Td = 20ns, 20 Frames per symbol
January 2005
Molisch et al., Preliminary Proposal
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Submission
P a r a m e t e r V a l u e ( T R -I R R e c e i v e r )
V a l u e ( T H -I R R e c e i v e r )
T h r o u g h p u t ( R b ) 6 0 8 K b / s 6 0 8 K b / s
A v e r a g e T x p o w e r ( TP ) - 4 . 3 d B m - 4 . 3 d B m
T x a n t e n n a g a i n ( TG ) 0 d B i 0 d B i
maxmin' fff c : g e o m e t r i c c e n t e r f r e q u e n c y o f
w a v e f o r m ( minf a n d maxf a r e t h e - 1 0 d B e d g e s
o f t h e w a v e f o r m s p e c t r u m )
5 . 7 3 G H z 5 . 7 3 G H z
P a t h l o s s a t 1 m e t e r ( )/4(lo g2 0 '1 01 cfL c )
81 03 c m / s
4 7 . 6 d B 4 7 . 6 d B
P a t h l o s s a t d m ( )(lo g2 0 1 02 dL ) 2 9 . 5 4 d B a t d = 3 0 m e t e r s
2 9 . 5 4 d B a t d = 3 0 m e t e r s
R x a n t e n n a g a i n ( RG ) 0 d B i 0 d B i
R x p o w e r (21 LLGGPP RTTR ( d B ) ) - 8 1 . 4 d B m - 8 1 . 4 d B m
A v e r a g e n o i s e p o w e r p e r b i t ( )(lo g*1 01 7 4 1 0 bRN )
- 1 1 6 . 2 d B m - 1 1 6 . 2 d B m
R x N o i s e F i g u r e R e f e r r e d t o t h e A n t e n n a T e r m i n a l (
FN ) 1 7 d B 7 d B
A v e r a g e n o i s e p o w e r p e r b i t ( FN NNP ) - 1 0 9 . 2 d B m - 1 0 9 . 2 d B m
M i n i m u m E b / N 0 ( S ) 1 2 d B 6 d B
I m p l e m e n t a t i o n L o s s 2 ( I ) 3 d B 3 d B
L i n k M a r g i n ( ISPPM NR ) 1 2 . 8 d B 1 8 . 8 d B
P r o p o s e d M i n . R x S e n s i t i v i t y L e v e l 3 - 9 4 . 2 d B m - 1 0 0 . 2 d B m
Link Budget
January 2005
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Submission
Ranging
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Submission
Two Step Ranging Algorithm
• Step-I: – Estimate rough TOA of the incoming signal in a time
window by detecting received signal energy
• Step-II:– Determine the arrival time of the first signal path by
using hypothesis testing (change detection)
January 2005
Molisch et al., Preliminary Proposal
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Submission
Step-I: Energy Detection
TRF TRB
1 2 … NB 1 2 … NB 1 2 … NBi =
1 2 N1j =
Y2,1 Y2,2 Y2,N1
2|)(| tr 2|)(| tr 2|)(| tr
Y2Y1 YNB
max
Block decisionStep-II
i = Ranging Block index
j = Ranging Frame index
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Step-II: Chip Detection
• TOA is estimated at chip resolution– Once a ranging block is detected, the chips in that block plus M1 extra chips
prior to the ranging block (to prevent errors due to multipath) are searched
– Correlations of the received signal with time delayed versions of a template signal are considered
– Correlation output is obtained over N2 frames to have sufficient SNR
– Solution of first arriving path found by hypothesis testing methods on zi
r(t), received signal
s(t-TC), shifted template signal
FC
C
TNiT
iT
2
(.) zi
January 2005
Molisch et al., Preliminary Proposal
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Submission
Ranging System Settings
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Submission
Ranging Results
• Residential LOS
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Ranging Results
• AWGN
January 2005
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Submission
Two-way Ranging Protocol
• Developed for transceivers that can first detect the coarse TOA of a signal and then determine the offset (error) of the coarse estimation
• No need to transmit extra information to correct the timing offset or the processing delay
• Each node switches between receive and transmit mode every T seconds until the ranging is complete
January 2005
Molisch et al., Preliminary Proposal
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Submission
Conventional Two-way Ranging Protocol
Enhanced Two-way Ranging Protocol
TOA estimation error
TOA estimation error
T
Second transmission may help filter out clock drifts, if the Tx has a more reliable clock
January 2005
Molisch et al., Preliminary Proposal
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Submission
Acquisition
• The first step of the TOA estimation algorithm is also suitable for acquisition
• For the second step of the acquisition, a conventional serial search algorithm, or the hypothesis testing based approach can be applied, depending on the complexity and performance constraints
• If ranging is performed no separate acquisition step is necessary
January 2005
Molisch et al., Preliminary Proposal
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Submission
Summary and Conclusions
• Impulse radio based standards proposal– UWB signaling achieves accurate ranging.
• Offers trade-off of cost/complexity/performance– Coherent and differentially coherent receivers suppress interference
• More users
• Innovative ways to manage spectrum– Meet FCC requirements– Improve performance in interference environment– Decrease interference to other systems
• Allows cheap implementation– All digital operations at symbol rate, not chip rate
January 2005
Molisch et al., Preliminary Proposal
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Submission
References
• Proposal content has been reviewed and published in various technical journals and conferences
– S. Gezici, F. Tufvesson, and A. F. Molisch, “On the performance of transmitted-reference impulse radio”, Proc. Globecom 2004,
– F. Tufvesson and A. F. Molisch, “Ultra-Wideband Communication using Hybrid Matched Filter Correlation Receivers“, Proc. VTC 2004 spring
– A. F. Molisch, Y. G. Li, Y. P. Nakache, P. Orlik, M. Miyake, Y. Wu, S. Gezici, H. Sheng, S. Y. Kung, H. Kobayashi, H.V. Poor, A. Haimovich,and J. Zhang, „A low-cost time-hopping impulse radio system for high data rate transmission“, Eurasip J. Applied Signal Processing, special issue on UWB
– S. Gezici, Z. Tian, G. B. Giannakis, H. Kobayashi, A. F. Molisch, H. Vincent Poor and Z. Sahinoglu, "Localization via Ultra-Wideband Radios," IEEE Signal Processing Magazine, invited paper (special issue)
– S. Gezici, E. Fishler, H. Kobayashi, H. V. Poor, and A. F. Molisch, “Performance Evaluation of Impulse Radio UWB Systems with Pulse-Based Polarity Randomization in Asynchronous Multiuser Environments”, Proc. WCNC 2004,
– S. Gezici, E. Fishler, H. Kobayashi, H. V. Poor, and A. F. Molisch, “Effect of timing jitter on the tradeoff between processing gains, Proc. ICC 2004, in press. F. Tufvesson and A. F. Molisch, “Ultra-Wideband Communication using Hybrid Matched Filter Correlation Receivers“, Proc. VTC 2004 spring
January 2005
Molisch et al., Preliminary Proposal
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Submission
References (Cont)
– Z. Sahinoglu, A. Catovic, "A Hybrid Location Estimation Scheme for Wireless Sensor Networks, IEEE ICC'04, June 2004, Paris
– S. Gezici, Z. Sahinoglu, H. Kobayashi, H. Vincent Poor, Book Chapter: Ultra Wideband Geolocation, Ultra Wideband Wireless Communications by H. Arslan and Z. N. Chen, John Wiley & Sons, Inc. , February 2005.
– S. Gezici, Z. Sahinoglu, H. Kobayashi, H. Vincent Poor, "Impulse Radio Systems with Multiple Types of UWB Pulses," submitted to ICASSP'05.
– A. Catovic, Z. Sahinoglu, "The Cramer-Rao Bounds of TOA/RSS and TDOA/RSS Location Estimation Schemes", IEEE Comm. Letters, October 2004
– H. Sheng, A. Haimovich, A. F. Molisch, and J. Zhang, “Optimum combining for time-hopping impulse radio UWB Rake receivers”, Proc. UWBST 2003, in press
– Li, Y.G.; Molisch, A.F.; Zhang, J., "Channel Estimation and Signal Detection for UWB", International Symposium on Wireless Personal Multimedia Communications (WPMC), October 2003
– Nakache, Y-P; Molisch, A.F., "Spectral Shape of UWB Signals - Influence of Modulation Format, Multiple Access Scheme and Pulse Shape", IEEE Vehicular Technology Conference (VTC), April 2003
