Design and implementation of digital filters with very high frequency response flexibility for multi-standard wireless communication receivers

Variable digital filters and reconfigurable filter banks (the filters and filter banks whose frequency response can be changed on-the-fly, based on the desired specifications) find application in multi-standard wireless communication receivers for channelization and spectrum sensing. Realization of...

Full description

Saved in:
Bibliographic Details
Main Author: Dhabu, Sumedh Somnath
Other Authors: Vinod Achutavarrier Prasad
Format: Theses and Dissertations
Language:English
Published: 2016
Subjects:
Online Access:http://hdl.handle.net/10356/66077
Tags: Add Tag
No Tags, Be the first to tag this record!
Institution: Nanyang Technological University
Language: English
id sg-ntu-dr.10356-66077
record_format dspace
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic DRNTU::Engineering::Electrical and electronic engineering::Electronic systems::Signal processing
DRNTU::Engineering::Electrical and electronic engineering::Wireless communication systems
spellingShingle DRNTU::Engineering::Electrical and electronic engineering::Electronic systems::Signal processing
DRNTU::Engineering::Electrical and electronic engineering::Wireless communication systems
Dhabu, Sumedh Somnath
Design and implementation of digital filters with very high frequency response flexibility for multi-standard wireless communication receivers
description Variable digital filters and reconfigurable filter banks (the filters and filter banks whose frequency response can be changed on-the-fly, based on the desired specifications) find application in multi-standard wireless communication receivers for channelization and spectrum sensing. Realization of area- and power-efficient, dynamically reconfigurable digital filters and filter banks is a challenging task. This thesis proposes area-efficient variable digital filters and reconfigurable filter bank architecture suitable for multi-standard wireless communication receivers. Proposed reconfigurable architectures offer different trade-offs between filter complexity and frequency response flexibility. In the first work, a low complexity design technique, termed as ‘improved coefficient decimation-interpolation-masking (IDIM)’ technique, is proposed to design low complexity, highly flexible variable filter and reconfigurable filter bank. The IDIM technique provides only discrete (coarse) control over the cutoff frequency. In multi-standard wireless communication receivers, it is desirable to have very fine or continuous (unabridged) control over the cutoff frequency of the variable filter. Fractional delay structure based filters provide very fine control over the cutoff frequency, at the cost of higher complexity. In the second work, fractional delay structure based variable filter designs using a novel fractional delay element are proposed. When compared to the existing fractional delay structure based filter, the proposed fractional delay structure based filters provide wider cutoff frequency range along with variable lowpass, bandpass, and highpass filter responses. The fractional delay structure based filters provide very fine control over the cutoff frequency, but in disjoint ranges. Also, they possess linear-phase property only in the passband region. Frequency transformation based filters provide a continuous control and have linear phase; but have very limited cutoff frequency range. The proposed modified second-order frequency transformation based filter provides a continuous control over the cutoff frequency on much wider range without increasing the transition bandwidth. Further, by integrating the second-order frequency transformation and interpolation techniques, a variable filter, termed as interpolated second-order frequency transformations based filter (ISFT filter), is proposed which can provide variable lowpass responses with narrow transition bandwidth over the entire Nyquist band. This design of variable lowpass filter is then extended to a bandpass filter with continuous and independent control over both the cutoff frequencies. The proposed transposed Taylor structure reduces the complexity of this bandpass filter and makes it suitable for designing reconfigurable filter banks. Spectral parameter approximation (SPA) based filters provide a continuous control over the cutoff frequency and offer trade-off between area and group delay with the frequency transformation based filters. Therefore, it is of interest to design low complexity SPA based filters which can provide similar cutoff frequency range as the proposed ISFT filter. A new time-domain approach is proposed in this thesis to design the SPA filters with reduced filter complexity. This time-domain approach is shown to result in lower filter complexity compared to the conventional design approach. Finally, the interpolation and SPA techniques based filter (ISPA filter) is proposed, which overcomes all the limitations of all the existing SPA based filters. Similar to the ISFT filter, the ISPA filter can provide a continuous control over the cutoff frequency in the entire Nyquist band along with narrow transition bandwidth. The viability and area-efficiency are also verified by the FPGA implementations of these proposed variable filters and it is shown that the ISPA and ISFT filters offer trade-offs between area, group delay and operating speed.
author2 Vinod Achutavarrier Prasad
author_facet Vinod Achutavarrier Prasad
Dhabu, Sumedh Somnath
format Theses and Dissertations
author Dhabu, Sumedh Somnath
author_sort Dhabu, Sumedh Somnath
title Design and implementation of digital filters with very high frequency response flexibility for multi-standard wireless communication receivers
title_short Design and implementation of digital filters with very high frequency response flexibility for multi-standard wireless communication receivers
title_full Design and implementation of digital filters with very high frequency response flexibility for multi-standard wireless communication receivers
title_fullStr Design and implementation of digital filters with very high frequency response flexibility for multi-standard wireless communication receivers
title_full_unstemmed Design and implementation of digital filters with very high frequency response flexibility for multi-standard wireless communication receivers
title_sort design and implementation of digital filters with very high frequency response flexibility for multi-standard wireless communication receivers
publishDate 2016
url http://hdl.handle.net/10356/66077
_version_ 1759853126911787008
spelling sg-ntu-dr.10356-660772023-03-04T00:34:41Z Design and implementation of digital filters with very high frequency response flexibility for multi-standard wireless communication receivers Dhabu, Sumedh Somnath Vinod Achutavarrier Prasad School of Computer Engineering Centre for High Performance Embedded Systems DRNTU::Engineering::Electrical and electronic engineering::Electronic systems::Signal processing DRNTU::Engineering::Electrical and electronic engineering::Wireless communication systems Variable digital filters and reconfigurable filter banks (the filters and filter banks whose frequency response can be changed on-the-fly, based on the desired specifications) find application in multi-standard wireless communication receivers for channelization and spectrum sensing. Realization of area- and power-efficient, dynamically reconfigurable digital filters and filter banks is a challenging task. This thesis proposes area-efficient variable digital filters and reconfigurable filter bank architecture suitable for multi-standard wireless communication receivers. Proposed reconfigurable architectures offer different trade-offs between filter complexity and frequency response flexibility. In the first work, a low complexity design technique, termed as ‘improved coefficient decimation-interpolation-masking (IDIM)’ technique, is proposed to design low complexity, highly flexible variable filter and reconfigurable filter bank. The IDIM technique provides only discrete (coarse) control over the cutoff frequency. In multi-standard wireless communication receivers, it is desirable to have very fine or continuous (unabridged) control over the cutoff frequency of the variable filter. Fractional delay structure based filters provide very fine control over the cutoff frequency, at the cost of higher complexity. In the second work, fractional delay structure based variable filter designs using a novel fractional delay element are proposed. When compared to the existing fractional delay structure based filter, the proposed fractional delay structure based filters provide wider cutoff frequency range along with variable lowpass, bandpass, and highpass filter responses. The fractional delay structure based filters provide very fine control over the cutoff frequency, but in disjoint ranges. Also, they possess linear-phase property only in the passband region. Frequency transformation based filters provide a continuous control and have linear phase; but have very limited cutoff frequency range. The proposed modified second-order frequency transformation based filter provides a continuous control over the cutoff frequency on much wider range without increasing the transition bandwidth. Further, by integrating the second-order frequency transformation and interpolation techniques, a variable filter, termed as interpolated second-order frequency transformations based filter (ISFT filter), is proposed which can provide variable lowpass responses with narrow transition bandwidth over the entire Nyquist band. This design of variable lowpass filter is then extended to a bandpass filter with continuous and independent control over both the cutoff frequencies. The proposed transposed Taylor structure reduces the complexity of this bandpass filter and makes it suitable for designing reconfigurable filter banks. Spectral parameter approximation (SPA) based filters provide a continuous control over the cutoff frequency and offer trade-off between area and group delay with the frequency transformation based filters. Therefore, it is of interest to design low complexity SPA based filters which can provide similar cutoff frequency range as the proposed ISFT filter. A new time-domain approach is proposed in this thesis to design the SPA filters with reduced filter complexity. This time-domain approach is shown to result in lower filter complexity compared to the conventional design approach. Finally, the interpolation and SPA techniques based filter (ISPA filter) is proposed, which overcomes all the limitations of all the existing SPA based filters. Similar to the ISFT filter, the ISPA filter can provide a continuous control over the cutoff frequency in the entire Nyquist band along with narrow transition bandwidth. The viability and area-efficiency are also verified by the FPGA implementations of these proposed variable filters and it is shown that the ISPA and ISFT filters offer trade-offs between area, group delay and operating speed. Doctor of Philosophy (SCE) 2016-03-09T02:07:36Z 2016-03-09T02:07:36Z 2016 Thesis http://hdl.handle.net/10356/66077 en 221 p. application/pdf