UWB Radio: Issues and Opportunities

UWB Radio: Issues and Opportunities

Jim Lansford, Ph.D.CTO, Alereon

[email protected]

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


3

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


4

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


5

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


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


7

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)


8

Here’s where we’re headed….

Coming to a retail store Coming to a retail store near you this fall!near you this fall!


9

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!)


10

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


11

Preview of DAA demo upstairs


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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


13

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!

UWB Radio: Issues and Opportunities

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