doc.: ieee 802.15-06-0xxx-00-0ban submission july, 2007 john f.m. gerrits / john r. farserotu,...
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doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 1
Project:Project: IEEE P802.15 Working Group for IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Wireless Personal Area Networks (WPANs) 15-07-0778-00-0ban
Submission Title: FM-UWB: A Low Complexity Constant Envelope LDR UWB Communication System
Date Submitted: 16 July, 2007
Source: John F.M. GerritsCSEM Systems EngineeringJaquet Droz 1, CH2002 Neuchatel, SwitzerlandVoice: +41 32 720 56 52, FAX: +41 32 720 57 20, E-Mail: john.gerrits@csem.ch
Re: This document is CSEM’s response to the Call For Application from the IEEE P802.15 Interest Group on BAN.
Abstract: This document presents FM-UWB: a constant envelope LDR UWB air interface for short range BAN applications.
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.
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 2
FM-UWB: A Low Complexity Constant Envelope
LDR UWB Communication System
• John F.M. Gerrits & John R. Farserotu• Wireless Communication Department• CSEM Systems Engineering• Switzerland
http://www.csem.ch http://www.fmuwb.ch
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 3
Presentation Outline
• Definition of and Applications for UWB
• Principles and Performance of FM-UWB
• Conclusions
Aalborg University ACORDE CEA-LETI Lund University
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 4
Definition of UWB
• Bandwidth > 500 MHz for operation above 3.1 GHz
• No particular air interface or modulation scheme specified
• Signal needs to comply with the local spectral mask
Over time, UWB has become less and less wideband..
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 5
Potential for UWB
• High Data Rate MBOFDM 480 Mbps • Robust MDR, Localization/tracking Impulse Radio 1-10 Mbps
• Very Robust LDR FM < 250 kbps
Very promising Business Potential.
[http://www.techworld.com/mobility/]
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 6
• The low radiated power of a UWB transmitter in principle may also yield low power consumption. May yield, since power may be required to meet, e.g., phase noise specifications or to perform baseband processing.
• Usually, the receiver requires more power than the transmitter (LNA gain, filtering, dynamic range)
• A MB OFDM transceiver will never be the champion of the low power contest.
Low power consumption potential of UWB
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 7
Short range (1-10m) Wireless Sensor Networks for monitoring and control:
Applications:• Health monitoring BAN • Home automation• Security and alarms
Requirements:• Low cost, low power systems (W - mWs)• Portable (go anywhere)• Robust and reliable• Good coexistence with other RF systems• Fast access (short synchronization time)
Low-complexity UWB applications
[IMEC]
BAN
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 8
Robust constant–envelope UWB: analog spread-spectrum
FM-UWB is an analog implementation of a spread-spectrum system:
• Spreading in transmitter by analog wideband FM ( = 500)
• Despreading in receiver wideband FM demodulator, yielding bandwidth reduction from 500 MHz to 200 kHz
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 9
FM-UWB features
True Low-Compexity and Robustness to interference and multipath
- Relaxed hardware specs (phase noise) > very low power potential
- No carrier synchronization but instantaneous despreading
- CSMA techniques may enhance performance
- Antennas are not critical
- Steep spectral roll-off
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 10
Sub-carrier Oscillator
RF Oscillator
d(t) m(t) V(t)
Subcarrier
Analog spreading in transmitter
spreading
BW: 50 kHz 200 kHz >500 MHz
freq: baseband 1 -2 MHz 4.5 & 6-9 GHz
modulation
FSK FM
RF Data
An analog FM signal can have any bandwidth independent of modulation frequency or bit rate. This is analog spread spectrum, i.e., multiple () copies of the FSK subcarrier signal.
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 11
Data, subcarrier and FM-UWB signal in time domain
RF
Subcarrier
Data
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 12
Direct Digital Synthesis subcarrier generation
Pre- filtering
Interpolating
DACDDSdin(t)m(t)13 10
SCLKNTX AMPTXSCLKSCLK
DEVd(t) A
fSUB = 1 MHzfSUB = 50 kHz
No look-up tabe is required for the generation of a triangular waveformData pre-filtering lowers subcarrier sidelobes to an acceptable level.
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 13
Relaxed phase noise requirements
A Low-Power Ring Oscillator can do the job:
Unmodulated at 4.5 GHz FM-UWB with f = 250 MHz
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 14
FM-UWB spectrum and Regulations
FM-UWB fits everywhere;even in the European 4.2 – 4.8 and 6 – 9 GHz spectrum.
FM roll-off
TX phase noise
TX white noise
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 15
Instantaneous despreading in the receiver
instantaneous despreading
BW: >500 MHz 200 kHz 50 kHzfreq: 4.5 & 6-9 GHz 1 -2 MHz baseband
LNAd(t)Wideband
FMDemodulator
Sub-carrierFilter &
Demodulator
FSKdemodulation
RF Subcarrier Data
R1
f2log10
B
Blog10G
SUB
RF10
SUB
RF10PdB
GPdB = 34 dB @ 100 kbpsGPdB = 44 dB @ 10 kbps
1
250 MHz
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 16
Receiver processing gain
R1
f2log10
B
Blog10G
SUB
RF10
SUB
RF10PdB
GPdB = 34 dB @ R = 100 kbpsGPdB = 44 dB @ R = 10 kbps
1
250 MHz
Only noise/interference in the subcarrier banwidth is taken into account.This bandwidth reduction after the wideband FM demodulator yieldsreal processing gain:
Processing gain increases for lower bit rates:
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 17
Wideband FM demodulator
VI VO
C
21
O f
f
2Ncos
2
AfV
cf4
N
4
TN
FM>PM
Phase det.
[ECWT 2006]
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 18
Multiple RF and subcarrier signals in receiver
At receiver input: 3 - 5 GHz (no multipath)
After FM demod:FSK subcarriers: 1 – 2 MHz
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 19
Receiver synchronization time
Due to the instantaneous despreading, only bit synchronizationis required like in a narrowband FSK system!
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 20
Multiple-access techniques
Multiple users can be accommodated in a number of ways:
• IEEE 802.15.4 MAC (TDMA) for standard applications
• RF FDMA, highest for QOS (no multiple-access interference)
• Sub-carrier FDMA (“MAC-less”) for ultra low power applications
• Proprietary MAC (TDMA) for sensor networks, e.g., WISENET
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 21
RF FDMA techniques
• Multiple users use different RF and sub-carrier frequencies• Highest QOS, since no multiple-access interference occurs (no spectral overlap)
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 22
Subcarrier FDMA techniques
• Multiple users can share the same RF center frequency• And distinguish themselves using different subcarrier frequencies
Subcarrier filtering, multiple-access interference and phase noise determine the performance limits.
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 23
Some figures on FM-UWB robustness1
• Impulse Radio interference with SIR = -14 dB yields BER = 10-3
• MBOFDM interference with SIR = -15 dB yields BER = 10-3
• FM-UWB performs very well in frequency-selective channels as we will illustrate shortly.
1values mentioned are for a 100 kbps system
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 24
Channel impulse response (time domain)
Performance with frequency-selective fading
Channel transfer function (frequency domain)
CM4CM1
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 25
FM-UWB performs better with strong multipath
CM1 1000 channel realizations CM4
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 26
good flat bad
Good, flat and bad channels
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 27
Statistics with various channels
CHANNEL MIN MAX AVG MEDIAN
CM1 -3.6 +2.1 -0.05 +0.10
CM2 -2.9 +2.0 -0.01 +0.01
CM3 -3.0 +1.9 -0.03 +0.04
CM4 -2.4 +1,6 -0.02 +0.02
Variations in RF sensitivity [dB] based upon 1000 channel realizations
[More at ICUWB2007]
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 28
Conclusions
FM-UWB is a Low-Complexity LDR UWB radio for BAN Applications:
Constant-envelope: low-voltage, low power Analog spread-spectrum with instantaneous despreading
RX synchronization time only bit-sync. limited Robustness to interference and multipath Simple radio architecture
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 29
doc.: IEEE 802.15-06-0xxx-00-0ban
Submission
July, 2007
John F.M. Gerrits / John R. Farserotu, CSEMSlide 30
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