| Περίληψη: | Modern embedded systems complexity, performance and energy efficiency
has been increasing steeply the last few years. An explosive
growth in demand for wireless communication is observed as well
and modern wireless links are expected to deliver bit rates of several
gigabits while consuming even less energy.
In order to satisfy these needs new technologies emerge and novel
design approaches are put into practice. Communication at 60 GHz
is such a technology that is able to deliver high bit rates in short
range wireless links. A major motivation to use the 60 GHz spectrum
is the worldwide availability which makes exploitation economically
viable. Moreover, small wavelength of only 5 mm promises
high integration due to small antenna component size which is one
of the main bottlenecks for reducing the dimensions.
However, increased frequency comes with many disadvantages as
well. To increase the market potential of such a new technology the
chip design needs to be cheap and energy-efficient. Such cost and
energy constrains heavily impact the performance and the quality
of both the analog and the digital components of the chip.
In the current thesis the design possibilities of a component in the
digital baseband of the receiver of such a chip are explored. The
component under investigation is a Fast Fourier Transform (FFT)
that is used for frequency domain equalization. This part of the
receiver is used to reduce the effects of multipath in a non line-ofsight
communication environment and as this is a common case in
wireless communication the FFT block has been identified as one
of the 2 most computational intensive components of the receiver
in 60 GHz. This is the main reason why we explore possibilities to
further decrease the power consumption of the block while maintaining
the performance and the quality of service.
To achieve this reduction the possibilities of a new design concept
are explored. System Scenarios is a new design concept for embedded
systems operating in dynamic environments. Wireless communication
systems exhibit high dynamism during their operation on
highly varying data streams, providing the System Scenarios huge
xvi
capabilities.
The essential idea behind system scenarios is the classification of
the application under investigation from a cost perspective during
design time. Then, the classification is exploited during run time resulting
to an overall improved implementation of the application. To
achieve this the application is broken down to run-time situations
(RTS) which are distinguishable operation modes of the application.
Then RTSs with similar costs are clustered to form system scenarios.
Finally for each scenario a different mapping and scheduling of
the application is generated.
In the case of the current thesis the application is the FFT and the
cost perspective is the power consumption of the component. To exploit
the RTS clustering in run time different quantization schemes
have been produced. These schemes have been generated based on
various properties of the data waveforms in the input of the FFT.
The thesis explores the potential of the System Scenarios as well as
the application of a quantization methodology for the FFT. Different
options of the RTS clustering and the quantization of the FFT block
are evaluated in order to come up with a more efficient implementation.
|
|---|
