17-03-2014, 12:44 PM
Abstract
By sharing building blocks between different
applications and standards, portable wireless devices
gain advantage over their predecessors: they use a
smaller chip area, consume less power, and have a
potential for lower overall cost. This requires the
development of adaptive circuits and systems that are
able to trade off power consumption for performance
on the fly. Realization of the adaptivity function
requires scaling of circuit parameters to the demands
of the signal-processing task. Basic aspects of the
mechanisms underlying the operation of adaptive
receivers and adaptive circuits will be examined in this
paper, and methodologies for their synthesis discussed.
1. Introduction
Progress in silicon integrated circuit (IC) technology
and innovations in IC design have enabled mobility of
wireless consumer products and services. Having
started out with limited performance capabilities
beyond simple telephony, mobile communications
technologies are now entering all aspects of our lives.
The communication devices of both today and the
future will have not only to allow for a variety of
applications, ranging from simple characters, via
speech, audio, and graphics to video, but they will also
have to maintain connection with many other devices
rather than with a single base station, in a variety of
environments. Moreover, to provide various services
from different wireless communication standards with
higher capacities and higher data-rates, fully integrated
and multifunctional wireless devices will be required.
However, extension of capabilities of wearable and
wireless devices depends critically on battery
endurance, as batteries continue to determine both the
lifetime and size of mobile equipment.
A combination of multiple functional requirements
and a small energy supply is an argument for the
design of adaptive low-power hardware and software.
Realization of the adaptivity functions requires new
design methodologies for transceiver circuits that trade
performance for power consumption in an adaptive
way. This eventually results in transceiver designs that
either consume less average power for a given
performance or offer better performance for a given
average power compared to conventional designs.
For adaptive low-noise amplifiers and mixers,
adaptivity relates to trading off dynamic range for
power consumption. For adaptive oscillators a trade-off
between phase noise, oscillation frequency and power
consumption matters, whereas for frequency
synthesizers we look at a trade-off between phaselocked
loop in-band noise and its settling time.
Adaptive multifunctional low-pass filters need to
compromise between the bandwidth, center frequency,
selectivity, while optimizing dynamic range and power
consumption. Analogue-to-digital converters must be
able to quantize signals belonging to various
communication standards, tailoring different sample
rate, dynamic range, and linearity requirements.
This paper describes relationships and trade-offs
between the performance parameters of adaptive
systems and their circuits. Some background on
multifunctional low-power wireless communication
circuits and systems is given in Section 2. Application
of adaptivity to multifunctional circuits and systems is
discussed in Section 3. The design of the adaptive
receiver circuits used in a multifunctional experimental
implementation is described in Section 4. Section 5 is
left for conclusions.
By sharing building blocks between different
applications and standards, portable wireless devices
gain advantage over their predecessors: they use a
smaller chip area, consume less power, and have a
potential for lower overall cost. This requires the
development of adaptive circuits and systems that are
able to trade off power consumption for performance
on the fly. Realization of the adaptivity function
requires scaling of circuit parameters to the demands
of the signal-processing task. Basic aspects of the
mechanisms underlying the operation of adaptive
receivers and adaptive circuits will be examined in this
paper, and methodologies for their synthesis discussed.
1. Introduction
Progress in silicon integrated circuit (IC) technology
and innovations in IC design have enabled mobility of
wireless consumer products and services. Having
started out with limited performance capabilities
beyond simple telephony, mobile communications
technologies are now entering all aspects of our lives.
The communication devices of both today and the
future will have not only to allow for a variety of
applications, ranging from simple characters, via
speech, audio, and graphics to video, but they will also
have to maintain connection with many other devices
rather than with a single base station, in a variety of
environments. Moreover, to provide various services
from different wireless communication standards with
higher capacities and higher data-rates, fully integrated
and multifunctional wireless devices will be required.
However, extension of capabilities of wearable and
wireless devices depends critically on battery
endurance, as batteries continue to determine both the
lifetime and size of mobile equipment.
A combination of multiple functional requirements
and a small energy supply is an argument for the
design of adaptive low-power hardware and software.
Realization of the adaptivity functions requires new
design methodologies for transceiver circuits that trade
performance for power consumption in an adaptive
way. This eventually results in transceiver designs that
either consume less average power for a given
performance or offer better performance for a given
average power compared to conventional designs.
For adaptive low-noise amplifiers and mixers,
adaptivity relates to trading off dynamic range for
power consumption. For adaptive oscillators a trade-off
between phase noise, oscillation frequency and power
consumption matters, whereas for frequency
synthesizers we look at a trade-off between phaselocked
loop in-band noise and its settling time.
Adaptive multifunctional low-pass filters need to
compromise between the bandwidth, center frequency,
selectivity, while optimizing dynamic range and power
consumption. Analogue-to-digital converters must be
able to quantize signals belonging to various
communication standards, tailoring different sample
rate, dynamic range, and linearity requirements.
This paper describes relationships and trade-offs
between the performance parameters of adaptive
systems and their circuits. Some background on
multifunctional low-power wireless communication
circuits and systems is given in Section 2. Application
of adaptivity to multifunctional circuits and systems is
discussed in Section 3. The design of the adaptive
receiver circuits used in a multifunctional experimental
implementation is described in Section 4. Section 5 is
left for conclusions.