6 research outputs found
Generic low power reconfigurable distributed arithmetic processor
Higher performance, lower cost, increasingly minimizing integrated circuit components, and
higher packaging density of chips are ongoing goals of the microelectronic and computer
industry. As these goals are being achieved, however, power consumption and flexibility are
increasingly becoming bottlenecks that need to be addressed with the new technology in Very
Large-Scale Integrated (VLSI) design.
For modern systems, more energy is required to support the powerful computational capability
which accords with the increasing requirements, and these requirements cause the change of
standards not only in audio and video broadcasting but also in communication such as wireless
connection and network protocols. Powerful flexibility and low consumption are repellent, but
their combination in one system is the ultimate goal of designers.
A generic domain-specific low-power reconfigurable processor for the distributed
arithmetic algorithm is presented in this dissertation. This domain reconfigurable processor
features high efficiency in terms of area, power and delay, which approaches the
performance of an ASIC design, while retaining the flexibility of programmable platforms.
The architecture not only supports typical distributed arithmetic algorithms which can be
found in most still picture compression standards and video conferencing standards, but
also offers implementation ability for other distributed arithmetic algorithms found in
digital signal processing, telecommunication protocols and automatic control.
In this processor, a simple reconfigurable low power control unit is implemented with
good performance in area, power and timing. The generic characteristic of the architecture
makes it applicable for any small and medium size finite state machines which can be used
as control units to implement complex system behaviour and can be found in almost all
engineering disciplines. Furthermore, to map target applications efficiently onto the
proposed architecture, a new algorithm is introduced for searching for the best common
sharing terms set and it keeps the area and power consumption of the implementation at
low level. The software implementation of this algorithm is presented, which can be used
not only for the proposed architecture in this dissertation but also for all the
implementations with adder-based distributed arithmetic algorithms. In addition, some low
power design techniques are applied in the architecture, such as unsymmetrical design
style including unsymmetrical interconnection arranging, unsymmetrical PTBs selection
and unsymmetrical mapping basic computing units. All these design techniques achieve
extraordinary power consumption saving. It is believed that they can be extended to more
low power designs and architectures.
The processor presented in this dissertation can be used to implement complex, high
performance distributed arithmetic algorithms for communication and image processing
applications with low cost in area and power compared with the traditional
methods
Design and Implementation of Complexity Reduced Digital Signal Processors for Low Power Biomedical Applications
Wearable health monitoring systems can provide remote care with supervised, inde-pendent living which are capable of signal sensing, acquisition, local processing and transmission. A generic biopotential signal (such as Electrocardiogram (ECG), and Electroencephalogram (EEG)) processing platform consists of four main functional components. The signals acquired by the electrodes are amplified and preconditioned by the (1) Analog-Front-End (AFE) which are then digitized via the (2) Analog-to-Digital Converter (ADC) for further processing. The local digital signal processing is usually handled by a custom designed (3) Digital Signal Processor (DSP) which is responsible for either anyone or combination of signal processing algorithms such as noise detection, noise/artefact removal, feature extraction, classification and compres-sion. The digitally processed data is then transmitted via the (4) transmitter which is renown as the most power hungry block in the complete platform. All the afore-mentioned components of the wearable systems are required to be designed and fitted into an integrated system where the area and the power requirements are stringent. Therefore, hardware complexity and power dissipation of each functional component are crucial aspects while designing and implementing a wearable monitoring platform. The work undertaken focuses on reducing the hardware complexity of a biosignal DSP and presents low hardware complexity solutions that can be employed in the aforemen-tioned wearable platforms.
A typical state-of-the-art system utilizes Sigma Delta (Σ∆) ADCs incorporating a Σ∆ modulator and a decimation filter whereas the state-of-the-art decimation filters employ linear phase Finite-Impulse-Response (FIR) filters with high orders that in-crease the hardware complexity [1–5]. In this thesis, the novel use of minimum phase Infinite-Impulse-Response (IIR) decimators is proposed where the hardware complexity is massively reduced compared to the conventional FIR decimators. In addition, the non-linear phase effects of these filters are also investigated since phase non-linearity may distort the time domain representation of the signal being filtered which is un-desirable effect for biopotential signals especially when the fiducial characteristics carry diagnostic importance. In the case of ECG monitoring systems the effect of the IIR filter phase non-linearity is minimal which does not affect the diagnostic accuracy of the signals.
The work undertaken also proposes two methods for reducing the hardware complexity of the popular biosignal processing tool, Discrete Wavelet Transform (DWT). General purpose multipliers are known to be hardware and power hungry in terms of the number of addition operations or their underlying building blocks like full adders or half adders required. Higher number of adders leads to an increase in the power consumption which is directly proportional to the clock frequency, supply voltage, switching activity and the resources utilized. A typical Field-Programmable-Gate-Array’s (FPGA) resources are Look-up Tables (LUTs) whereas a custom Digital Signal Processor’s (DSP) are gate-level cells of standard cell libraries that are used to build adders [6]. One of the proposed methods is the replacement of the hardware and power hungry general pur-pose multipliers and the coefficient memories with reconfigurable multiplier blocks that are composed of simple shift-add networks and multiplexers. This method substantially reduces the resource utilization as well as the power consumption of the system. The second proposed method is the design and implementation of the DWT filter banks using IIR filters which employ less number of arithmetic operations compared to the state-of-the-art FIR wavelets. This reduces the hardware complexity of the analysis filter bank of the DWT and can be employed in applications where the reconstruction is not required. However, the synthesis filter bank for the IIR wavelet transform has a higher computational complexity compared to the conventional FIR wavelet synthesis filter banks since re-indexing of the filtered data sequence is required that can only be achieved via the use of extra registers. Therefore, this led to the proposal of a novel design which replaces the complex IIR based synthesis filter banks with FIR fil-ters which are the approximations of the associated IIR filters. Finally, a comparative study is presented where the hybrid IIR/FIR and FIR/FIR wavelet filter banks are de-ployed in a typical noise reduction scenario using the wavelet thresholding techniques. It is concluded that the proposed hybrid IIR/FIR wavelet filter banks provide better denoising performance, reduced computational complexity and power consumption in comparison to their IIR/IIR and FIR/FIR counterparts
Foundations of Security Analysis and Design III, FOSAD 2004/2005- Tutorial Lectures
he increasing relevance of security to real-life applications, such as electronic commerce and Internet banking, is attested by the fast-growing number of research groups, events, conferences, and summer schools that address the study of foundations for the analysis and the design of security aspects. This book presents thoroughly revised versions of eight tutorial lectures given by leading researchers during two International Schools on Foundations of Security Analysis and Design, FOSAD 2004/2005, held in Bertinoro, Italy, in September 2004 and September 2005. The lectures are devoted to: Justifying a Dolev-Yao Model under Active Attacks, Model-based Security Engineering with UML, Physical Security and Side-Channel Attacks, Static Analysis of Authentication, Formal Methods for Smartcard Security, Privacy-Preserving Database Systems, Intrusion Detection, Security and Trust Requirements Engineering