Sep 19, 2002 ... The most over-hyped wireless technology in the past few years ... Difficult for
small companies with new technologies to break into ..... Cellonics.
IEEE Oakland/East Bay Communications Society
Ultra-Wideband (UWB) Technology for Communication Applications Sep 19, 2002 Roberto Aiello
[email protected]
Sep 19, 2002
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What is UWB? ?
The most over-hyped wireless technology in the past few years!!!! BUT……….
? ?
7,500MHz of available unlicensed spectrum Great opportunity for ? ?
low bit rate, low power networks (low duty cycle) very high bit rate short range networks (large bandwidth)
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Summary ? ? ? ? ?
Definition and characteristics Performance in the real world UWB receivers Potential advantages Commercial opportunities
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FCC Regulatory Proceedings
1998
1999
FCC initiates UWB approval process with NOI (Sept ’98) Over 50 public comments on NOI filed (Fall ‘98)
Sep 19, 2002
2000
2001
NPRM issued (May ’00)
2002
NTIA tests completed and released (Jan ‘01)
Over 250 public comments on NPRM filed (Summer ‘00)
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UWB R&O (Feb 14 ‘01)
~780 filings submitted to FCC (Dec ’01)
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Few Lessons Learned from Regulatory Process
?
FCC filings (docket# 98-153) ? ? ?
? ?
?
Difficult to develop technologies with private equity funding without ? ?
?
Lot of material submitted to the FCC Technical and non-technical material mixed in the submissions Extremely difficult to separate valid technical arguments from marketing claims (on both supporting and opposing sides) Very few refereed and scientific papers presented EVERY company will support ANY argument that will further their case
regulatory approval deterministic regulatory process
Difficult for small companies with new technologies to break into the establishment Sep 19, 2002
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Definition of UWB fH ? fL ? ? 2 ? 20% fH ? fL
? A radio signal with fractional bandwidth (? ) larger than 20%. ? Examples:
Amplitude (dB)
0
-3
(802.11a,
-6
Channel 36)
-> 0.4%,
?
3-4 GHz
-> 29%,
?
2-5 GHz
-> 86%
fL
fH
-10 -3dB or -10dB or -20dB point
0
0.5
1
2
Frequency (GHz) Sep 19, 2002
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UWB definitions* ?
7,500MHz available spectrum for unlicensed use ? US operating frequency: 3,100 – 10,600 MHz ? Emission limit: -41.3dBm/MHz EIRP ? Indoor and handheld systems ? Other restrictions and measurement procedures in Report & Order
?
UWB device defined as ? Fractional bandwidth greater than 20% ? Occupies more than 500 MHz
?
UWB device NOT defined as ? Modulation or pulsed modulation ? Carrierless ? Impulse radio
*Source: FCC 02-48, UWB Report & Order, released 22 April 02 Sep 19, 2002
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FCC spectral mask (indoor)
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FCC spectral mask (outdoor)
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XtremeSpectrum
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PPM (source: Time Domain)
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Transmit signal
Think at a UWB signal as a very short RF burst (gaussian shaped in this case) Sep 19, 2002
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UWB Channel Characteristics
?
Signal bandwidth much greater than coherence bandwidth => Frequency-selective channel
?
Symbol duration much smaller than coherence time (Doppler spread much smaller than signal bandwidth) => Slow-fading channel Sep 19, 2002
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Multipath (1 of 4)
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Multipath (2 of 4)
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Multipath (3 of 4)
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Multipath (4 of 4)
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Source: Time Domain
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Source: Time Domain
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Source: Time Domain
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UWB Classification (source: GA) ?
PRF ? ? ?
The rate at which pulses are transmitted, i.e. # pulses/second PRF represents the average rate if pulses are transmitted aperiodically Implies a specific Power/Pulse • FCC limits impose power/pulse as a function of PRF • Drops 3dB with each doubling of PRF
?
Duty Cycle
?
Ton is dominated by Delay Spread ? ?
Amplitude
Ton (Ton + Toff)
Ton + Toff = 1/PRF Duty Cycle ? Delay Spread * PRF
T off
T on 1/PRF
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Mutual Interference of UWB Systems (source: GA) Impact of High PRF on:
Power
Power
Impact of Low PRF on:
High PRF
Pulse Period
Time Pulse Period
Time
Variable Impact (function of coding)
Power
Power
Tricky!
Low PRF
Time
Power
Pulse Period
Pulse Period Pulse Period
Low Impact (function of duty cycle)
Sep 19, 2002
Time
Time
Low Impact (noise like)
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Analog front-end comparison Antenna
r Typical QAM analog front-end Front-End Bandpass Filter
Low Noise Amplifier
Bandpass Filter
Bandpass Filter
Lowpass Filter
Analog to Digital Converter
Lowpass Filter
Analog to Digital Converter
I Output
Gain Controlled Amplifier
Q Output
I/Q Local Oscillator
Local Oscillator
r UWB analog front-end Bandpass Filter
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Low Noise Amplifier
Baseband Detector
Gain Controlled Amplifier
Analog to Digital Converter
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Simple receiver Antenna Output
LNA Output
non-coherent detector output THRESHOLD
BB Amplifer Output
COMPVAL
Peak Detect and Dump Output
STROBE
Patent: US 6,275,544 More information in: “A UWB Architecture for Wireless Video Networking”, G.R.Aiello, L. Taylor, M. Ho (ICCE 2001) Sep 19, 2002
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PHY Partitioning Baseband Bits
RF Symbols
Coded Bits
Code/Decode
Mod/Demod
PMD
Gain Control
Antenna
Sync
Power Control
Generic Radio PMD - Physical Medium Dependent
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Potential advantages What
Why
Low cost
Baseband radio architecture
Low power
Low transmit duty cycle
Co-existence
Low power spectral density
Interference robust
Large bandwidth (processing gain)
High capacity
Large bandwidth
Multipath robust
Large bandwidth (frequency diversity)
Communication/location
Large bandwidth (fast rise time)
NOT ALL AT THE SAME TIME!!! Sep 19, 2002
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Multipath fading Pulse Repetition Interval (PRI)
Amplitude
??
Time
Gating Width (T)
?
? T ~ T or PRI for multipath interference
Narrow pulse widths ? ?
Less likelihood of constructive/destructive summation Less margin required for multipath fading
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Capacity ?
Capacity basically ? ?
C ? W log 2 (1 ? SNR )
?
Alternative channel model ? ? ?
?
Sep 19, 2002
Proportional to bandwidth W LOG proportional to SNR
Multipath fading Perfect channel information Few dominant paths
Capacity approaches AWGN capacity as bandwidth increases
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Example link budget Transmitter parameters Bandwidth Number of frequency channels Center frequency Pulse repetition frequency Total bit rate Transmitter FCC limit Tx voltage/pulse (pk-pk) into 50Ohm Receiver parameters Rx antenna gain Noise figure Ep/No Receiver parameters Available SNR (signal pk/noise rms) Range (d = 2)
Sep 19, 2002
0.5 15 3.5 20 300
2.5 3 3.5 20 60
GHz GHz MHz Mbps
-41.25 -41.25 dBm/MHz 0.61 3.06 V 4 7 8
4 dBi 7 dB 8 dB
35.41 177
42.40 dB 395 ft
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Market comparison 802.11a 802.11g 802.11b
1,000 Power [mW] 100
Bluetooth 2.0
802.15.3
802.15.3a
Bluetooth 1.1
Discrete Time Intel General Atomics Time Domain Wisair Xtreme Spectrum
10
ZigBee 1
Discrete Time
0.1 0.01
0.1
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1
10
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Bit rate [Mb/s]
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IEEE 802.15.3a Summary Requirements ? ? ? ? ? ? ?
Bit rate: 110-200Mbps, option to 480Mbps Range: 30ft Power consumption: 100mW BER (top of the PHY): 10e-5 Co-located piconets: 4 Cost: similar to Bluetooth Co-existent with 802.11a
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IEEE 802.15.3a Original Schedule November (2001) December January (2002) March July October November
Today
January (2003) March (2003) May (2003) July (2003) September (2003)
Sep 19, 2002
Approve 15.3a Study Group Issue Call For Applications Application Presentations Application Presentations Channel Model Presentations Issue Call For Proposals Approval of PAR by ExCom Approval of PAR and 5 Criteria by WG Proposal Presentations Proposal Presentations Proposal Presentations Proposal Selection Voting Generation and acceptance of baseline draft text Presentation and approval of Alt PHY draft text Approval to conduct a letter ballot
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UWB Companies* Company
Location
Initial market
Bay Area Bay Area DC Alabama DC
VC Capital raised N/A N/A N/A ~$50M ~$27M
Localizers Radar Military WLAN WPAN
Time to market ? Now Now 2002 2002
Aetherwire LLNL Multispectral Time Domain Xtreme Spectrum General Atomics Intel Pulselink Pulsicom
San Diego Bay Area San Diego Israel
N/A N/A Two rounds Seed
WPAN WPAN Wireless Nwks Location
2003 N/A 2003 ?
Cellonics Discrete Time Comm. I-tech Wisair
Singapore Bay Area Slovenia Israel
? Seed ? $4.2M
IP licensing (?) Low power, WPAN Discrete TX/RX WPAN/WLAN
Now 2003 Now ?
*information derived from companies’public announcements and websites
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Conclusions ? ? ? ? ? ?
UWB is 7,500MHz of available unlicensed spectrum Exciting opportunity for new technologies Performance in real world is tricky Coordination of UWB vendors useful to increase interoperability and co-existence UWB industry focused on high bit rate WPANs (IEEE 802.15.3a) Market opportunity for ? ?
low bit rate, low power networks (low duty cycle) very high bit rate short range networks (large bandwidth)
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