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Status of BWRC Jan 2000 Retreat

The Center Goal. Develop methods for specifying, optimizing, simulating, verifying and implementing all aspects of wireless systemsApplication definitionCommunication algorithm and protocol designAnalog and digital architectural optimizationIC implementation and test. Center activities. Tw

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Status of BWRC Jan 2000 Retreat

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    1. Status of BWRC Jan 2000 Retreat http://bwrc.eecs.berkeley.edu

    2. The Center Goal Develop methods for specifying, optimizing, simulating, verifying and implementing all aspects of wireless systems Application definition Communication algorithm and protocol design Analog and digital architectural optimization IC implementation and test

    3. Center activities Two basic center application drivers Universal spectrum sharing PicoRadios Investigate tradeoffs between various implementation architectures with respect to flexibility, power and area Develop a rapid implementation design flow from the high level specifications to an integrated realization.

    4. Application Drivers 1) Universal Spectrum Sharing An approach to channel utilization which allows uncoordinated use of spectra without loss in capacity Extensible over time to exploit advances in technology and support new applications 2) PicoRadio System on a chip implementation supporting all functions up to external interface (sensors, transducers) Total power dissipation in the 100’s of microwatts achieved through optimization of protocols and architectures

    5. Architectural Choices

    6. The Automated Design Environment

    7. Research Contract Drivers Design Environment for Single Chip Radios (DARPA) - 1 M/Yr - 9/2000 Intercom Design flow PicoNode (DARPA) - 1 M/Yr - 9/2002 Power Aware Computing Program Communications for arrays of sensors Ultra Wideband Radios (ONR) – 100k/Yr –1/2003

    8. Center Activities

    9. Outline Introduction Algorithms Design Methodology Baseband Analog and RF design

    10. Approach to Spectrum Sharing Three “types” of dimensionality in signal space Time Frequency Physical Space Need to exploit all these degrees of freedom to maximize the number of users and to minimize their interference with each other

    11. Time dimension TDMA and CDMA are ways to exploit this dimension Divide up Tsymbol into Nt =Tsymbol/ Tchip segments Nt degrees of freedom in available bandwidth, fBW

    12. Direct Sequence Spread Spectrum Receiver can distinguish between each code providing CDMA (Code Division Multiple Access) However there is interference if there is multipath, so ….

    13. CDMA with MUD Multiuser detection reduces the interference between codes due to multipath and thus improves the capacity of CDMA

    14. Frequency dimension How about using the frequency dimension? Simple method is FDM (Frequency Division Multiplexing), one frequency per user OFDM uses all frequencies for each user, like DSSS uses all time slots (Nf degrees of freedom)

    15. Both together Obtain NfNt degrees of freedom Many options in combining the two dimensions…

    16. Now what about physical space? Another set of options that can be used in many ways: Increase efficiency so that less signal space is used per user (BLAST like algorithms) Increase energy in useful directions so that signal to noise improves Provide isolation between users However requires multiple antennas to be flexible enough for mobile users

    17. Another option – Ultra Wideband Effort starting up to investigate the issues in transmitting data over extremely wide bandwidths Data modulated onto extremely fast transitions (CMOS is great for that) Wideband antenna design is critical – antenna basically sets the bandwidth From information theory standpoint, inefficient use of spectrum is best for lowest energy transmission

    18. Shannon likes UWB!

    19. This mornings algorithm session Spatial processing: Describes the close relationship of various multi antenna array algorithms (Beamforming, BLAST and SVD) Frequency domain processing: OFDM and its sensitivity to impairments Frequency/time domain options: MC CDMA, COFDM, … Proposed frequency/time/spatial design

    20. Outline Introduction Algorithms Design Methodology BEE

    21. The Automated Design Environment

    22. Simulink description of radio system

    23. Baseband equivalent analog modeling

    24. This afternoon : The protocol/radio interface

    25. Tuesday morning – digital design flow

    26. Analog Design (Tuesday Morning)

    27. Center Activities

    28. The BEE - Bigascale Emulation Engine) Sufficient processing capability to support real time operation of complex baseband algorithms, with attached analog frontends Arrays of FPGA’s and potentially DSP’s Same input description as chip design The goal is to provide a realtime testbed for the advanced algorithm development

    29. The BEE Hardware (G. Wright)

    30. BEE and the BWRC Design Flow

    31. Accomplishments System defined which exploits all the signal space dimensions Time: Direct Sequence Frequency: OFDM Space: Multi Element Arrays First test circuit almost through the automed design flow First test circuits of .25 micron direct conversion analog front end in measurement Multistandard radio test chip in testing

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