uwb radio: issues and opportunities
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UWB Radio: Issues and Opportunities
Jim Lansford, Ph.D.CTO, Alereon
jim.lansford@alereon.com
We’re not going to talk about the Rose Bowl today!
USC UWB Symposium - April 2006
2
Agenda
Issues• Is regulatory really solved?• What about standards?• What are the remaining design challenges?
Opportunities• What are the research opportunities?• What about 60GHz?
Wrapup
USC UWB Symposium - April 2006
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Is regulatory really solved?We are getting closer –
• US, Japan, and Korea are done…but DAA is an open issue• Europe is still a problem• China is in process
Detect and Avoid (DAA) is required, but not defined!CEPT Japan USA
- 40
- 45
- 50
- 55
- 60
- 65
- 70
- 75
- 80
- 85
- 90
- 95
UW
B EI
RP D
ensi
ty, d
Bm/M
Hz
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.510.0 12.512.011.511.0
Frequency, GHz
- 41.3 dBm/MHz
3.4 4.8 7.25 10.25
1.61
1.99 3.1 10.6
Korea
- 41.3 dBm/MHz
1.61
2.7
7.1 10.5 3.1 4.95 6
9
USC UWB Symposium - April 2006
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What about standards?
IEEE is dead…• But it doesn’t matter!• The race is essentially over…
There is a standard – WiMedia’s Multiband OFDM• WiMedia MB-OFDM was ratified as ECMA-368/369 in Dec 2005• ISO standard by the end of the summer• Recent WiMedia interop tests had six different interoperable
chipsets – not FPGAs, not second source, but true independent solutions
Certified Wireless USB uses ECMA-368/369• Products will go into production this summer
Bluetooth has adopted WiMedia UWB• Above 6GHz bands only• Software layers above the WiMedia MAC• Will enter market in 2007
USC UWB Symposium - April 2006
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What are the remaining design challenges?
Note: I’m only going to talk about WiMedia (MB-OFDM)
This is a “race to the bottom”• Lowest power• Lowest cost (this does not imply single die – reasonable people may
disagree)Hardware needs some evolution
• Better ADCs – 6 –bits, low power >528MHz sampling• Optimized FFT and Viterbi engines – pretty straightforward• 90nm solutions have the potential to be pretty good!
As usual, software is now important• Microsoft, Intel, etc. are engaged – Microsoft is way ahead of the
curve in wUSB compared to wired USB…Vista support is coming!The DAA goals are still not clear, so we will continue to have to put lots of general hooks in place
USC UWB Symposium - April 2006
6WiMedia/Certified Wireless USB/UWBoBT
ADC
DAC
FFT/IFFT
Filter/Decimate
Interp ./Filter
AGC
Detect
DespreadDemapDeinterleaveDepuncture
Viterbi
SpreadingMappingInterleavePuncture
Convo -lutionalCoder
MA
C/P
HY
Interface
Chan EstCFO
Equalize
ADC
DAC
FFT/IFFT
Filter/Decimate
Interp ./Filter
AGC
Detect
DespreadDemapDeinterleaveDepuncture
Viterbi
SpreadingMappingInterleavePuncture
Convo -lutionalCoder
MA
C/P
HY
Interface
Chan EstCFO
Equalize
Mixer &Filter
Mixer &Filter
90°
Baseband/MAC RF
10mm x 10mm5mm x 5mm
USC UWB Symposium - April 2006
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WiMedia MAC is flexible
The WiMedia MAC can support many protocol stacks over the same radio
PAL: Protocol Adaptation Layer
WiMedia MAC Convergence Architecture (WiMCA)
&/or
PAL PAL WiNET
&/or &/or
PAL
IP
WiMedia MACWiMedia PHY (MB-OFDM)
USC UWB Symposium - April 2006
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Here’s where we’re headed….
Coming to a retail store Coming to a retail store near you this fall!near you this fall!
USC UWB Symposium - April 2006
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What are the research opportunities?
Detect and Avoid (DAA)• Better power spectral shaping• Improved detection algorithms
Circuits• Improved ADCs – higher speed, lower power, scalable
– Future UWB may go to higher bandwidth– Converter power will always be critical issue
• Variable bias point RF – low power for benign environments, higher power for interference
• Optimal/scalable quantization for soft decision ViterbiAntennas/filters
• WLAN, UMTS supression• European 3-5GHz supression to -85dBm/MHz (hope not!)
USC UWB Symposium - April 2006
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DAA in a WiMedia TDMA MAC
WiMedia MAC is TDMASlots can be reserved for spectrum sampling
• All network Tx shut offLarger number of slots increases probability of detecting beacon
• But reduces UWB data throughputWork continues to explore cyclostationary signals
FFT bin number
FFT
fram
e nu
mbe
r
20 40 60 80 100 120
50
100
150
200
250
300
350
400
0 20 40 60 80 100 120 1400
0.5
1
1.5
2x 10
4
0 20 40 60 80 100 120 1400
5
10
15
20
25
Averaged
Instantaneous
WiMax beacons
256μS
USC UWB Symposium - April 2006
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Preview of DAA demo upstairs
USC UWB Symposium - April 2006
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What about 60GHz?
Complements existing UWB• Higher speeds than practical with UWB• More power allows increased range• Excellent support for “point and shoot” file transfers
– iPod, digital camera, other mobile devices
Will end up as part of the WPAN ecosystem over timeWon’t replace UWB, IMHO
• Some usage models (WPAN) aren’t well suited to 60GHz physics
• Dual radios will happen - someday
USC UWB Symposium - April 2006
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Wrapup…
Commercial deployment of UWB (MB-OFDM) is happening
• Multiple interoperable sources of silicon rushing to market• ISO standards• USB-IF and Bluetooth support
Regulatory will remain interestingPlenty of interesting research remains!Look for UWB products on the shelves this fall!
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