Markku Renfors - Academia.edu (original) (raw)

Papers by Markku Renfors

1999 IEEE Pacific Rim Conference on Communications, Computers and Signal Processing (PACRIM 1999). Conference Proceedings (Cat. No.99CH36368), 1999

Polynomial-based interpolation techniques are an attractive approach for discrete-time processing... more Polynomial-based interpolation techniques are an attractive approach for discrete-time processing of continuous-time signals. These techniques are employing discrete time filters for enabling arbitrary resampling of a time series, and have been used in several applications. In this contribution we investigate and analyze some new design methods and possible applications of this polynomial-based interpolation utilizing the Farrow structure

The 13th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, 2002

The problem of closely-spaced paths in DS-CDMA systems is a challenging task at the baseband rece... more The problem of closely-spaced paths in DS-CDMA systems is a challenging task at the baseband receiver for applications such as mobile location and RAKE receivers. Previously, we introduced a method based on Teager-Kaiser (1990) operator for resolving paths spaced at less than one chip distance. We compare the performance of TK operator with that of the subspace based MUSIC (multiple

This paper describes the design and implementa- tion of a single chip 32 channel PCM transmit fil... more This paper describes the design and implementa- tion of a single chip 32 channel PCM transmit filter. The processing elements are time-shared between 32 input signals, which are sampled at 32 kHz. The filter decimates the sampling rate to 8 kHz and performes the required spectrum shaping. The unique stability properties of wave digital filters are utilized to insure correct

2008 IEEE 19th International Symposium on Personal, Indoor and Mobile Radio Communications, 2008

This work presents a new technique for blind and joint estimation of symbol timing and carrier fr... more This work presents a new technique for blind and joint estimation of symbol timing and carrier frequency offset in wireless orthogonal frequency division multiplexing (OFDM) systems. The joint estimation is achieved by sensing the interference introduced at the fast Fourier transform (FFT) output when a carrier frequency or timing offsets exist. The synchronization parameters are selected such that the interference is minimized. The proposed joint estimator is highly efficient because it does not require any overhead or channel state information. Simulation results show that the system is effective and robust even at low signal-to-noise ratios.

This paper concentrates on an efficient prototype filter de- sign in the context of filter bank b... more This paper concentrates on an efficient prototype filter de- sign in the context of filter bank based multicarrier (FBMC) transmission. An advantage of the chosen method, frequency sampling technique, is that near perfect reconstruction pro- totype filters can be expressed using a closed-form represen- tation with only a few adjustable parameters. The perfor- mance of various designs are analyzed using

In I/Q processing receivers, matching the amplitudes and phases of the I- and Q-branches is of ma... more In I/Q processing receivers, matching the amplitudes and phases of the I- and Q-branches is of major concern. In practise, matching can n ever be perfect i n the analog front-end which results in insufficient rejection of the image frequency band. As a c onsequence, the desired channel signal i s interfered b y up to 50 -100 dB stronger

International Conference on Acoustics, Speech, and Signal Processing, 1986

This paper introduces a new class of uniform digital filter banks based on DFT and recursive Nth-... more This paper introduces a new class of uniform digital filter banks based on DFT and recursive Nth-band filters. We consider both even and odd types of channel stacking arrangements. Due to the use of the DFT, the basic filter bank is complex. Real filter banks are obtained by adding the output signals from two symmetrically located complex channels. The filter

IEEE Transactions on Acoustics, Speech, and Signal Processing, 1988

The implementation of digital filter structures of all-pass subfilters using modern high-speed si... more The implementation of digital filter structures of all-pass subfilters using modern high-speed signal processors is investigated. The focus is on digital all-pass filters realized as a cascade of first- and second-order all-pass sections. Wave digital all-pass sections are considered, with special emphasis on developing two-port adaptor structures that are suitable for signal processor implementation. Explicit formulas are developed for scaling

2004 IEEE International Symposium on Circuits and Systems (IEEE Cat. No.04CH37512), 2004

The non-uniform sampling of the signal can be product of an intentional or unintentional process.... more The non-uniform sampling of the signal can be product of an intentional or unintentional process. For example jitter sampling is an unintentional process which is a consequence of time error of sampling circuits. In many DSP applications it is very important to reconstruct the signal from its non-uniformity distributed samples, especially to obtain a uniformly sampled sequence. This paper presents

1991., IEEE International Sympoisum on Circuits and Systems, 1991

... From Eq. (4) it also follows that the transfer functions G2(z) and H2(z) are magnitudecomplem... more ... From Eq. (4) it also follows that the transfer functions G2(z) and H2(z) are magnitudecomplementary, ie the sum of their magnitude responses is a constant. ... These fil-ters can also be used for the design of improved magnitude complementary filter pairs. Acknowledgements ...

Proceedings of ICC/SUPERCOMM'94 - 1994 International Conference on Communications, 1994

This paper presents an investigation of orthogonal frequency division multiplexing (OFDM) signal ... more This paper presents an investigation of orthogonal frequency division multiplexing (OFDM) signal distortion in an amplitude limited channel. In the presence of both limiter distortion and channel noise, the back-off can be optimized to give maximum signal-to-noise ratio for a given system

International Conference on Digital Signal Processing, 2002

The current emphasis in radio transceiver design is on technologies suitable for integration on a... more The current emphasis in radio transceiver design is on technologies suitable for integration on a single silicon chip. In order to simplify the receiver analog front-end and, thus, to enhance the receiver integrability, I/Q signal processing has received growing research interest. In practical analog implementations, the main barrier is vulnerability to amplitude and phase mismatches. We discuss the possibilities of

2004 IEEE International Symposium on Circuits and Systems (IEEE Cat. No.04CH37512), 2004

Interpolation filters are used to interpolate new sample values at arbitrary points between exist... more Interpolation filters are used to interpolate new sample values at arbitrary points between existing discrete-time samples. An interesting class of such filters is polynomial-based interpolation filter. These filters can be efficiently implemented using the Farrow structure and its modifications. Traditionally, the polynomial based interpolation filters have been implemented by using Farrow structure with finite impulse response (FIR) subfilters of even

2000 IEEE International Conference on Communications. ICC 2000. Global Convergence Through Communications. Conference Record, 2000

2002 IEEE International Symposium on Circuits and Systems. Proceedings (Cat. No.02CH37353), 2002

This paper explores subband processing of complex (I/Q) signals which finds various important app... more This paper explores subband processing of complex (I/Q) signals which finds various important applications especially in communications signal processing. Instead of using traditional DFT based systems, the filter bank based systems are very interesting choices when high selectivity in the subchannels is required. We present a novel efficient complex modulated critically sampled filter bank structure which is based on a

ICECS'99. Proceedings of ICECS '99. 6th IEEE International Conference on Electronics, Circuits and Systems (Cat. No.99EX357), 1999

In this paper we apply the idea of cosine-modulated perfect reconstruction filter banks to develo... more In this paper we apply the idea of cosine-modulated perfect reconstruction filter banks to develop efficient transmultiplexers for multicarrier VDSL transmission systems of the Discrete Wavelet Multitone type. The effects of the design parameters (number of channels, roll-off, filter lengths) on the implementation complexity are evaluated through design examples. Based on a simplified interference model, criteria are developed for evaluating the reduction in data transmission rate due to nonideal filter bank design, i.e, finite number of channels and nonzero roll-off. The cosine-modulated transmultiplexer is also analyzed from the data modulation point-of-view and similarity of the critically sampled filter bank approach to other approaches known in the literature is discussed.

IEEE Vehicular Technology Conference, 2006

... With a two layer ARQ concept, each flow can have a separate ARQ entity allowing that ARQ ... ... more ... With a two layer ARQ concept, each flow can have a separate ARQ entity allowing that ARQ ... provided in this section lead to the following ARQ concept proposal for LTE: • HARQ handles ... a transport block that may contain data from more than one radio bearer (MAC multiplexing ...

1998 URSI International Symposium on Signals, Systems, and Electronics. Conference Proceedings (Cat. No.98EX167), 1998

A new all-digital technique for clock and carrier phase synchronization of digital receivers was ... more A new all-digital technique for clock and carrier phase synchronization of digital receivers was introduced by the authors. This technique is based on a polynomial approximation of the likelihood function and utilizes the Farrow (1988) structure for symbol interpolation. In this article, we analyze the effect of frequency offset or Doppler shift on the performance of the receiver while adjusting

ISCAS'99. Proceedings of the 1999 IEEE International Symposium on Circuits and Systems VLSI (Cat. No.99CH36349), 1999

1999 IEEE Pacific Rim Conference on Communications, Computers and Signal Processing (PACRIM 1999). Conference Proceedings (Cat. No.99CH36368), 1999

Polynomial-based interpolation techniques are an attractive approach for discrete-time processing... more Polynomial-based interpolation techniques are an attractive approach for discrete-time processing of continuous-time signals. These techniques are employing discrete time filters for enabling arbitrary resampling of a time series, and have been used in several applications. In this contribution we investigate and analyze some new design methods and possible applications of this polynomial-based interpolation utilizing the Farrow structure

The 13th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, 2002

The problem of closely-spaced paths in DS-CDMA systems is a challenging task at the baseband rece... more The problem of closely-spaced paths in DS-CDMA systems is a challenging task at the baseband receiver for applications such as mobile location and RAKE receivers. Previously, we introduced a method based on Teager-Kaiser (1990) operator for resolving paths spaced at less than one chip distance. We compare the performance of TK operator with that of the subspace based MUSIC (multiple

This paper describes the design and implementa- tion of a single chip 32 channel PCM transmit fil... more This paper describes the design and implementa- tion of a single chip 32 channel PCM transmit filter. The processing elements are time-shared between 32 input signals, which are sampled at 32 kHz. The filter decimates the sampling rate to 8 kHz and performes the required spectrum shaping. The unique stability properties of wave digital filters are utilized to insure correct

2008 IEEE 19th International Symposium on Personal, Indoor and Mobile Radio Communications, 2008

This work presents a new technique for blind and joint estimation of symbol timing and carrier fr... more This work presents a new technique for blind and joint estimation of symbol timing and carrier frequency offset in wireless orthogonal frequency division multiplexing (OFDM) systems. The joint estimation is achieved by sensing the interference introduced at the fast Fourier transform (FFT) output when a carrier frequency or timing offsets exist. The synchronization parameters are selected such that the interference is minimized. The proposed joint estimator is highly efficient because it does not require any overhead or channel state information. Simulation results show that the system is effective and robust even at low signal-to-noise ratios.

This paper concentrates on an efficient prototype filter de- sign in the context of filter bank b... more This paper concentrates on an efficient prototype filter de- sign in the context of filter bank based multicarrier (FBMC) transmission. An advantage of the chosen method, frequency sampling technique, is that near perfect reconstruction pro- totype filters can be expressed using a closed-form represen- tation with only a few adjustable parameters. The perfor- mance of various designs are analyzed using

In I/Q processing receivers, matching the amplitudes and phases of the I- and Q-branches is of ma... more In I/Q processing receivers, matching the amplitudes and phases of the I- and Q-branches is of major concern. In practise, matching can n ever be perfect i n the analog front-end which results in insufficient rejection of the image frequency band. As a c onsequence, the desired channel signal i s interfered b y up to 50 -100 dB stronger

International Conference on Acoustics, Speech, and Signal Processing, 1986

This paper introduces a new class of uniform digital filter banks based on DFT and recursive Nth-... more This paper introduces a new class of uniform digital filter banks based on DFT and recursive Nth-band filters. We consider both even and odd types of channel stacking arrangements. Due to the use of the DFT, the basic filter bank is complex. Real filter banks are obtained by adding the output signals from two symmetrically located complex channels. The filter

IEEE Transactions on Acoustics, Speech, and Signal Processing, 1988

The implementation of digital filter structures of all-pass subfilters using modern high-speed si... more The implementation of digital filter structures of all-pass subfilters using modern high-speed signal processors is investigated. The focus is on digital all-pass filters realized as a cascade of first- and second-order all-pass sections. Wave digital all-pass sections are considered, with special emphasis on developing two-port adaptor structures that are suitable for signal processor implementation. Explicit formulas are developed for scaling

2004 IEEE International Symposium on Circuits and Systems (IEEE Cat. No.04CH37512), 2004

The non-uniform sampling of the signal can be product of an intentional or unintentional process.... more The non-uniform sampling of the signal can be product of an intentional or unintentional process. For example jitter sampling is an unintentional process which is a consequence of time error of sampling circuits. In many DSP applications it is very important to reconstruct the signal from its non-uniformity distributed samples, especially to obtain a uniformly sampled sequence. This paper presents

1991., IEEE International Sympoisum on Circuits and Systems, 1991

... From Eq. (4) it also follows that the transfer functions G2(z) and H2(z) are magnitudecomplem... more ... From Eq. (4) it also follows that the transfer functions G2(z) and H2(z) are magnitudecomplementary, ie the sum of their magnitude responses is a constant. ... These fil-ters can also be used for the design of improved magnitude complementary filter pairs. Acknowledgements ...

Proceedings of ICC/SUPERCOMM'94 - 1994 International Conference on Communications, 1994

This paper presents an investigation of orthogonal frequency division multiplexing (OFDM) signal ... more This paper presents an investigation of orthogonal frequency division multiplexing (OFDM) signal distortion in an amplitude limited channel. In the presence of both limiter distortion and channel noise, the back-off can be optimized to give maximum signal-to-noise ratio for a given system

International Conference on Digital Signal Processing, 2002

The current emphasis in radio transceiver design is on technologies suitable for integration on a... more The current emphasis in radio transceiver design is on technologies suitable for integration on a single silicon chip. In order to simplify the receiver analog front-end and, thus, to enhance the receiver integrability, I/Q signal processing has received growing research interest. In practical analog implementations, the main barrier is vulnerability to amplitude and phase mismatches. We discuss the possibilities of

2004 IEEE International Symposium on Circuits and Systems (IEEE Cat. No.04CH37512), 2004

Interpolation filters are used to interpolate new sample values at arbitrary points between exist... more Interpolation filters are used to interpolate new sample values at arbitrary points between existing discrete-time samples. An interesting class of such filters is polynomial-based interpolation filter. These filters can be efficiently implemented using the Farrow structure and its modifications. Traditionally, the polynomial based interpolation filters have been implemented by using Farrow structure with finite impulse response (FIR) subfilters of even

2000 IEEE International Conference on Communications. ICC 2000. Global Convergence Through Communications. Conference Record, 2000

2002 IEEE International Symposium on Circuits and Systems. Proceedings (Cat. No.02CH37353), 2002

This paper explores subband processing of complex (I/Q) signals which finds various important app... more This paper explores subband processing of complex (I/Q) signals which finds various important applications especially in communications signal processing. Instead of using traditional DFT based systems, the filter bank based systems are very interesting choices when high selectivity in the subchannels is required. We present a novel efficient complex modulated critically sampled filter bank structure which is based on a

ICECS'99. Proceedings of ICECS '99. 6th IEEE International Conference on Electronics, Circuits and Systems (Cat. No.99EX357), 1999

In this paper we apply the idea of cosine-modulated perfect reconstruction filter banks to develo... more In this paper we apply the idea of cosine-modulated perfect reconstruction filter banks to develop efficient transmultiplexers for multicarrier VDSL transmission systems of the Discrete Wavelet Multitone type. The effects of the design parameters (number of channels, roll-off, filter lengths) on the implementation complexity are evaluated through design examples. Based on a simplified interference model, criteria are developed for evaluating the reduction in data transmission rate due to nonideal filter bank design, i.e, finite number of channels and nonzero roll-off. The cosine-modulated transmultiplexer is also analyzed from the data modulation point-of-view and similarity of the critically sampled filter bank approach to other approaches known in the literature is discussed.

IEEE Vehicular Technology Conference, 2006

... With a two layer ARQ concept, each flow can have a separate ARQ entity allowing that ARQ ... ... more ... With a two layer ARQ concept, each flow can have a separate ARQ entity allowing that ARQ ... provided in this section lead to the following ARQ concept proposal for LTE: • HARQ handles ... a transport block that may contain data from more than one radio bearer (MAC multiplexing ...

1998 URSI International Symposium on Signals, Systems, and Electronics. Conference Proceedings (Cat. No.98EX167), 1998

A new all-digital technique for clock and carrier phase synchronization of digital receivers was ... more A new all-digital technique for clock and carrier phase synchronization of digital receivers was introduced by the authors. This technique is based on a polynomial approximation of the likelihood function and utilizes the Farrow (1988) structure for symbol interpolation. In this article, we analyze the effect of frequency offset or Doppler shift on the performance of the receiver while adjusting

ISCAS'99. Proceedings of the 1999 IEEE International Symposium on Circuits and Systems VLSI (Cat. No.99CH36349), 1999