high rate - ultra wide band (uwb) background ecma/ga/2005/038
TRANSCRIPT
High Rate - Ultra Wide Band (UWB)Background
Ecma/GA/2005/038
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Promise of a UWB Physical Layer
Data rates:• Scalable data rates from 55 Mb/s to 480 Mb/s.• 110 Mb/s at 10 meters in realistic multi-path environments.• 200 Mb/s at greater than 4 meters in realistic multi-path environments.• 480 Mb/s at 2 meters in realistic multi-path environments.
Low cost solutions.
Low power PHY solutions:
Integrated CMOS solution Single chip solutions Small form factors.
Coexistence with current and future devices.
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Overview of Multi-band OFDM
Central Idea #1:
• Divide the spectrum into bands that are 528 MHz wide.
Advantages:
• Transmitter and receiver process smaller bandwidth signals.
• Instantaneous processing BW = 528 MHz.
f3432MHz
3960MHz
4488MHz
5016MHz
5544MHz
6072MHz
6600MHz
7128MHz
7656MHz
8184MHz
8712MHz
9240MHz
9768MHz
Band #1
Band #2
Band #3
Band #4
Band #5
Band #6
Band #7
Band #8
Band#9
Band #10
Band #11
Band #12
Band #13
10296MHz
Band #14
Band Group #1 Band Group #2 Band Group #3 Band Group #4 Band Group #5
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Exploiting the Band Plan
Exploit range of band group’s to separate applications:
Longer Range Apps Use BG #1 and #2
f3432MHz
3960MHz
4488MHz
5016MHz
5544MHz
6072MHz
Band #1
Band #2
Band #3
Band #4
Band #5
Band #6
Band Group #1 Band Group #2
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Exploiting the Band Plan
Exploit range of band group’s to separate applications:
` Shorter Range Apps Use BG #3 and #4
f3432MHz
3960MHz
4488MHz
5016MHz
5544MHz
6072MHz
6600MHz
7128MHz
7656MHz
8184MHz
8712MHz
9240MHz
9768MHz
Band #7
Band #8
Band#9
Band #10
Band #11
Band #12
10296MHz
Band Group #3 Band Group #4
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Overview of Multi-band OFDM
Central Idea #2:
• Interleave OFDM symbols across all bands.
Advantages:
• Exploits frequency diversity.
• Provide robustness against multi-path / interference.
• Same transmit power as if the entire band is used.
TimeFreq (MHz)
3168
3696
4752
4224
Band # 1
Band # 2
Band # 3
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Transmitter Architecture
Block Diagram:
Architecture is similar to that of a conventional/proven OFDM system.
Major Differences:
1. Time-Frequency kernel specifies the frequency for next OFDM symbol.
2. Constellation size is limited to QPSK (limits size of IFFT/FFT, DAC/ADC).
3. For rates less than 80 Mb/s, the input to the IFFT is conjugate symmetric.• Need to only implement the “I” portion of TX analog chain. • As a result, only half the analog die size of a full “I/Q” transmitter is needed.
4. Zero-padded prefix instead of cyclic prefix.
ScramblerInputData FEC Interleaver Mapper IFFT DAC
exp(j2fct)
Time-FrequencyKernel
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Conclusions
Inherent robustness to multi-path in all expected environments.
Excellent robustness to U-NII and other generic narrowband interference.
Ability to comply with worldwide regulations:
• Channels and tones can be turned on/off dynamically to comply with changing regulations.
• Can arbitrarily shape spectrum because the tones resolution is ~4 MHz.
Example: Radio-astronomy bands in Japan.
• Only need to zero out a few tones in order to protect these services.
Channel #1 Typical OFDM waveform Channel #1 Waveform with J apaneseradioastronomical bands protected.
3260 -3267 MHz3332 - 3339 MHz3345.8 -3352.5 MHz
-f
-f
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Rue du Rhône 114CH-1204 GenevaT: +41 22 849 6000 F: +41 22 849 6001
www.ecma-international.org