doc.: IEEE 802.15-09/0005r1 Submiss ion January 2009 Slide 1 Slide 1 Project: IEEE P802.15 Working Group for Wireless Personal Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Area Networks (WPANs) Submission Title: Frequency Shifted Reference UWB Physical Layer Date Submitted: January 12, 2008 Source: Dennis L. Goeckel, PhD; Qu Zhang, PhD; Robert Jackson, PhD; Zhiguo Lai, PhD,; Department of Electrical and Computer Engineering, University of Massachusetts at Amherst, Amherst, Massachusetts Contact: Fanny Mlinarsky Voice: +1 (978) 376-5841, E-Mail: [email protected]Abstract: FSR-UWB based PHY layer for BAN Networks Purpose: Overview of the FSR-UWB technology developed at University of Massachusetts at Amherst 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 contributors reserve 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 Fanny Mlinarsky, [email protected]
Transcript
doc.: IEEE 802.15-09/0005r1
Submission
January 2009
Slide 1Slide 1
Project: IEEE P802.15 Working Group for Wireless Personal Area Networks Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)(WPANs)
Submission Title: Frequency Shifted Reference UWB Physical Layer
Date Submitted: January 12, 2008
Source: Dennis L. Goeckel, PhD; Qu Zhang, PhD; Robert Jackson, PhD; Zhiguo Lai, PhD,; Department of Electrical and Computer Engineering, University of Massachusetts at Amherst, Amherst, Massachusetts
Abstract: FSR-UWB based PHY layer for BAN Networks
Purpose: Overview of the FSR-UWB technology developed at University of Massachusetts at Amherst
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 contributors reserve 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 in March’08 it would be made publicly available by P802.15.
Time-frequency Interleaving (TFI) or Fixed Frequency Interleaving (FFI) is used to spread the transmit power among the three sub-bands thereby increasing the peak transmit power and optimizing the range.
Multi-Band
doc.: IEEE 802.15-09/0005r1
Submission
January 2009
TR-UWB• TR-UWB was a strong candidate signaling scheme in the original
effort of 802.15.4a (location and low data rate applications), but a major implementational issue – delay line – killed this approach– Eventually the group adapted burst mode PPM (pulse position
modulation)
• In the TR-UWB systems [3] each frame consists of two pulses– The first is a reference pulse and has a fixed polarity
– The second is the data pulse and follows the reference pulse with some known delay, D
– The reference pulse provides a template to which to match the data pulse
)2cos( 0tf Delay line replaced by oscillator/mixer
[4]-[6] outline challenges
[7]-[8]
Frequency Shifted Reference
doc.: IEEE 802.15-09/0005r1
Submission
January 2009
Complexity of TR-UWB vs. Simplicity of FRS-UWB
• The General Electric team developed a testbed for the standard TR-UWB that required a 20-foot coaxial cable in the receiver because of the need for a 20ns wideband analog delay element [11].
• The proposed FSR-UWB system is simple enough to have been implemented by University of Massachusetts at Amherst undergraduates.
– The prototype operates with at up to10 kbps in the 600 MHz-7 GHz range
• Our simulations based on the latest BAN channel models demonstrate feasibility of 10 Mbps operation
• FSR-UWB system uses a reference that is a slightly frequency-shifted version of the data-bearing signal.
• The reference signal and data signal are orthogonal over a symbol interval.
• For low data rates, the frequency shift between the reference signal and data signal is small compared to the channel coherence bandwidth. The reference goes through approximately the same
• A symbol interval Ts = Nf * Tf ; Nf frames, each of duration Tf
• Nf can be increased until either:
– The gains from the increased average energy are offset by the degradation due to interframe interference (IFI), or…
– The FCC spectral limit is reached
• FSR-UWB requires only 1 pulse per frame, vs. TR-UWB that requires 2 pulses per frame, which means that Nf can be higher for FSR-UWB, improving signal integrity
• FSR-UWB is also more tolerant of IFI and, thus, can employ a higher Nf to improve average energy aggregation;
• With the FCC constraint Nf,FSR=5.83*Nf,TR
• Over a wide range of error probabilities and constraints, FSR-UWB offers a 1.0 to 1.5 dB gain over TR-UWB
FSR-UWB System Considerations• In the FSR-UWB, a frequency offset between the reference impulse train and
data impulse train is the inverse of the symbol period.
• Pulse shaping waveform is half the frequency of the data rate and this frequency, f0 = 1/(2*TS), must be below the frequency coherence of the channel
• Frequency coherence of the channel – the bandwidth over which the channel is roughly constant – is described by the channel models
• Symbol timing, δ, must also be synchronized [symbol clock]– This can be achieved using adaptive algorithms to minimize Е[Λ2(δ)] versus δ
The delay element of the standard TR-UWB scheme has been replaced by a mixer in (a). Since multiplication is commutative, the receiver in (a) can be drawn in the more convenient form given in (b).
References (1 of 3)[1] IEEE 802.15 WPAN Low Rate Alternative PHY Task Group 4a (TG4a),
“http://www.ieee802.org/15/pub/TG4a.html.”
[2] M. Z. Win and R. A. Scholtz, “On the energy capture of ultra-wide bandwidth signals in dense multipath environments,”IEEE Commun. Lett., vol. 2, pp. 245–247, Sept. 1998.
[3] R. Hoctor and H. Tomlinson, An overview of delay-hopped, transmittedreference RF communications, General Electric Technical Report 2001CRD198, Jan. 2002.
[4] M. Casu and G. Durisi, “Implementation aspects of a transmittedreference UWB receiver,” Wireless Communications and Mobile Computing, Vol. 5: pp. 537-549, May 2005.
[5] L. Feng and W. Namgoong, “An oversampled channelized UWB receiver with transmitted reference modulation,” to appear in the IEEE Transactions on Wireless Communications.
[6] S. Bagga, S. Haddad, W. Serdijn, J. Long and E. Busking, “A delay filter for an IR-UWB front-end,” Proceedings of the IEEE International Conference on Ultra-wideband, pp. 323-327, Sept., 2005.
References (2 of 3)[7] D. Goeckel and Q. Zhang, “Slightly frequency-shifted reference ultrawideband
(UWB) radio: TR-UWB without the delay element,” Proceedings of the Military Communication Conference, Oct., 2005.
[8] D. Goeckel and Q. Zhang, “Slightly frequency-shifted reference ultrawideband (UWB) radio”, revision submitted to the IEEE Transactions on Communications.
[9] Q. Zhang and D. Goeckel, “Multi-Differential Slightly Frequency-Shifted Reference Ultra-Wideband (UWB) Radio,” Proceedings of the Conference on Information Sciences and Systems, March 2006.
References (3 of 3)[10] A. Stigliari, “Design and characterization of a planar ultra-wide band
antenna”, MS dissertation, Electrical and Computer Engineering, University of Massachusetts Amherst, Feb., 2005.
[11] N. van Stralen, A. Dentinger, K. Welles II, R. Gaus Jr., R. Hoctor, and H. Tomlinson, ”Delay hopped transmitted reference experiemental results”, Proceedings of UWBST, pp. 93-98, May 2002.
[12] J. Proakis and D. Manolokis, Digital signal processing, Prentice-Hall, third edition, 1996.
[13] A. Batra, J. Balakrishnan, G. Aiello, J. Foerster, and A. Dabak, “Design of a Multiband OFDM System for Realistic UWB Channel Environments,” IEEE Transactions on Microwave Theory and Techniques, Vol. 52: pp. 2123-2138, September 2004.
