DVB-H offers reliable high data rate reception for mobile handheld and battery-powered devices. A... more DVB-H offers reliable high data rate reception for mobile handheld and battery-powered devices. A link layer with error correction is defined to work on top of the DVB-T physical layer. The DVB-H standard suggests to use Reed-Solomon coding combined with cyclic redundancy check error detection as the link layer forward error correction. However, there exist more powerful methods for decoding. In this paper, a detailed comparison of five different decoding strategies is presented of which all are compatible with the current standard. Comparison is based on frame error, IP packet error and byte error rates after decoding. Also, the effect of errors on visual experience of a video stream is analyzed
In this paper, we study the quality of the terrestrial digital video broadcasting (DVB-T) transmi... more In this paper, we study the quality of the terrestrial digital video broadcasting (DVB-T) transmission over the cable TV network. Usually, when terrestrial digital TV signals are distributed in the cable TV network a conversion is needed in the head-end, from DVB-T (OFDM) to DVB-C (single carrier). In this work we study the possibility of using the DVB-T signal without
The aim of this paper is to investigate the effects of impulsive noise on the performance of the ... more The aim of this paper is to investigate the effects of impulsive noise on the performance of the maximum likelihood symbol synchronization (MLSS) algorithm in OFDM systems. Limitations of the MLSS algorithm are shown. Simulations results of the timing offset mean squared error (MSE) in static and mobile channels are considered. Ideas to enhance the performance of the algorithm in these environments are also proposed.
Abstract In this paper, a blind carrier frequency offset (CFO) estimation method for multi-input ... more Abstract In this paper, a blind carrier frequency offset (CFO) estimation method for multi-input multi-output orthogonal frequency division multiplexing (MIMO-OFDM) systems is proposed. The proposed method is based on minimizing the power difference between all ...
In this paper, we present an enhanced least mean square (LMS) based feedback loop interference ca... more In this paper, we present an enhanced least mean square (LMS) based feedback loop interference canceller algorithm intended to be used in digital terrestrial broadcasting single frequency network (SFN) via single on-channel repeater system (OCR). The feedback loop interference is caused by the coupling that could exist between transmitting and receiving antennas. The performance of the method is evaluated in BER sense assuming a Rayleigh channel between the main transmitter and the repeater with multi-tap feedback loop having either Ricean or Rayleigh profile.
This work considers the effect of timing errors on the carrier frequency offset (CFO) estimation ... more This work considers the effect of timing errors on the carrier frequency offset (CFO) estimation for orthogonal frequency division multiplexing (OFDM) systems. In general, most of the research conducted on OFDM systems assume that a wide range of timing errors can be tolerated due to the use of cyclic prefix (CP). Although such assumption might be valid for bit error
This paper presents a new blind symbol timing offset (STO) estimation scheme for wireless orthogo... more This paper presents a new blind symbol timing offset (STO) estimation scheme for wireless orthogonal frequency division multiplexing (OFDM) systems with constant modulus constellation. In the proposed scheme, the STO estimation is performed by minimizing the power difference between either adjacent or consecutive subcarriers, which basically depends on the assumptions made on the channel conditions. Monte Carlo simulation is used to assess the two realizations of the proposed system. The system performance is evaluated by means of mean squared error (MSE) over additive white Gaussian noise (AWGN) and frequency selective mobile radio channels. The simulation results demonstrate that the MSE of the proposed system is well below the MSE of other well-established estimators reported in the literature.
This paper describes different techniques for mitigation of high power and long duration interfer... more This paper describes different techniques for mitigation of high power and long duration interference in terrestrial digital video broadcasting (DVB-T/H) systems. The interference is assumed to distort the DVB-T/H signal severely so that on average one fourth of the DVB-T/H symbol is lost. We investigate the use of long enough time interleaver in combination with simple soft bits scaling. Additional mitigation of the interference effects is also achieved using the pilots carried by the DVB-T/H signal. The mitigation schemes are evaluated in the case where the interference occurs in additive white Gaussian noise (AWGN) and static frequency selective channels.
We study the quality of terrestrial digital video broadcasting (DVB-T) transmission over a cable ... more We study the quality of terrestrial digital video broadcasting (DVB-T) transmission over a cable TV network. Generally, when terrestrial digital TV signals are distributed by cable TV, a conversion from DVB-T (OFDM) to DVB-C (single carrier) is needed in the head-end. In order to avoid this costly conversion and to transmit the DVB-T signal directly in the existent cable channel, many requirements have to be satisfied. It is known that phase noise represents the main limitation for OFDM based systems. In this contribution, we demonstrate the sensitivity of the OFDM system to phase noise effects by using a dynamic model for the CATV channel. We conclude by giving the specifications for a converter that should allow the DVB-T system to function in the CATV network
This paper presents an efficient blind symbol timing estimation scheme for orthogonal frequency-d... more This paper presents an efficient blind symbol timing estimation scheme for orthogonal frequency-division multiplexing (OFDM) systems with constant modulus constellation. The proposed technique is designed to estimate symbol timing offsets by minimizing the power difference between subcarriers with similar indices over two consecutive OFDM symbols based on the assumption that the channel slowly changes over time. The proposed power difference estimator (PDE) is totally blind because it requires no prior information about the channel or the transmitted data. Monte Carlo simulation is used to assess the PDE performance in terms of the probability of correct timing estimate Plock-in. Moreover, we propose a new performance metric denoted as the deviation from safe region (DSR). Simulation results have demonstrated that the PDE performs well in severe frequency-selective fading channels and outperforms the other considered estimators. The complexity of the PDE can be significantly reduced by incorporating a low-cost estimator to provide initial coarse timing information. The proposed PDE is realized using feedforward and early-late gate (ELG) configurations. The new PDE-ELG does not suffer from the self-noise problem inherent in other ELG estimators reported in the literature.
We introduce a new method to enhance the tolerability of the pilot based impulse noise canceller ... more We introduce a new method to enhance the tolerability of the pilot based impulse noise canceller presented in J. Rinne et al. (2002) in time and frequency selective environments. The method uses a quantized value of the carrier deviations caused by the presence of the impulsive interference to weight the soft bits in the digital terrestrial receiver. Hence more reliability against the impulse burst is achieved. The performance of the new method is compared to conventional receiver structures in different fading environments. Ricean and Rayleigh static channel cases are used to evaluate the system performance in bit error rate (BER) sense. Also a mobile channel case with moderate Doppler spread is considered.
This paper discusses the use of the autocorrelation method introduced in A. Hazmi et al. (2002) t... more This paper discusses the use of the autocorrelation method introduced in A. Hazmi et al. (2002) to cancel multi-tap loop interference with exponential profile in digital terrestrial broadcasting using relays. It was shown that the method can cancel efficiently the coupling between the transmitter and the receiver antennas in the relay station when one tap loop model is considered. Here we modify the autocorrelation method to deal with multi-tap loop with exponential profile. Analytical and experimental results are presented to verify the advantages and the limitations of the method in such environment. Bit error rate simulation results are also considered in AWGN and Rayleigh static channels cases
DVB-H offers reliable high data rate reception for mobile handheld and battery-powered devices. A... more DVB-H offers reliable high data rate reception for mobile handheld and battery-powered devices. A link layer with error correction is defined to work on top of the DVB-T physical layer. The DVB-H standard suggests to use Reed-Solomon coding combined with cyclic redundancy check error detection as the link layer forward error correction. However, there exist more powerful methods for decoding. In this paper, a detailed comparison of five different decoding strategies is presented of which all are compatible with the current standard. Comparison is based on frame error, IP packet error and byte error rates after decoding. Also, the effect of errors on visual experience of a video stream is analyzed
In this paper, we study the quality of the terrestrial digital video broadcasting (DVB-T) transmi... more In this paper, we study the quality of the terrestrial digital video broadcasting (DVB-T) transmission over the cable TV network. Usually, when terrestrial digital TV signals are distributed in the cable TV network a conversion is needed in the head-end, from DVB-T (OFDM) to DVB-C (single carrier). In this work we study the possibility of using the DVB-T signal without
The aim of this paper is to investigate the effects of impulsive noise on the performance of the ... more The aim of this paper is to investigate the effects of impulsive noise on the performance of the maximum likelihood symbol synchronization (MLSS) algorithm in OFDM systems. Limitations of the MLSS algorithm are shown. Simulations results of the timing offset mean squared error (MSE) in static and mobile channels are considered. Ideas to enhance the performance of the algorithm in these environments are also proposed.
Abstract In this paper, a blind carrier frequency offset (CFO) estimation method for multi-input ... more Abstract In this paper, a blind carrier frequency offset (CFO) estimation method for multi-input multi-output orthogonal frequency division multiplexing (MIMO-OFDM) systems is proposed. The proposed method is based on minimizing the power difference between all ...
In this paper, we present an enhanced least mean square (LMS) based feedback loop interference ca... more In this paper, we present an enhanced least mean square (LMS) based feedback loop interference canceller algorithm intended to be used in digital terrestrial broadcasting single frequency network (SFN) via single on-channel repeater system (OCR). The feedback loop interference is caused by the coupling that could exist between transmitting and receiving antennas. The performance of the method is evaluated in BER sense assuming a Rayleigh channel between the main transmitter and the repeater with multi-tap feedback loop having either Ricean or Rayleigh profile.
This work considers the effect of timing errors on the carrier frequency offset (CFO) estimation ... more This work considers the effect of timing errors on the carrier frequency offset (CFO) estimation for orthogonal frequency division multiplexing (OFDM) systems. In general, most of the research conducted on OFDM systems assume that a wide range of timing errors can be tolerated due to the use of cyclic prefix (CP). Although such assumption might be valid for bit error
This paper presents a new blind symbol timing offset (STO) estimation scheme for wireless orthogo... more This paper presents a new blind symbol timing offset (STO) estimation scheme for wireless orthogonal frequency division multiplexing (OFDM) systems with constant modulus constellation. In the proposed scheme, the STO estimation is performed by minimizing the power difference between either adjacent or consecutive subcarriers, which basically depends on the assumptions made on the channel conditions. Monte Carlo simulation is used to assess the two realizations of the proposed system. The system performance is evaluated by means of mean squared error (MSE) over additive white Gaussian noise (AWGN) and frequency selective mobile radio channels. The simulation results demonstrate that the MSE of the proposed system is well below the MSE of other well-established estimators reported in the literature.
This paper describes different techniques for mitigation of high power and long duration interfer... more This paper describes different techniques for mitigation of high power and long duration interference in terrestrial digital video broadcasting (DVB-T/H) systems. The interference is assumed to distort the DVB-T/H signal severely so that on average one fourth of the DVB-T/H symbol is lost. We investigate the use of long enough time interleaver in combination with simple soft bits scaling. Additional mitigation of the interference effects is also achieved using the pilots carried by the DVB-T/H signal. The mitigation schemes are evaluated in the case where the interference occurs in additive white Gaussian noise (AWGN) and static frequency selective channels.
We study the quality of terrestrial digital video broadcasting (DVB-T) transmission over a cable ... more We study the quality of terrestrial digital video broadcasting (DVB-T) transmission over a cable TV network. Generally, when terrestrial digital TV signals are distributed by cable TV, a conversion from DVB-T (OFDM) to DVB-C (single carrier) is needed in the head-end. In order to avoid this costly conversion and to transmit the DVB-T signal directly in the existent cable channel, many requirements have to be satisfied. It is known that phase noise represents the main limitation for OFDM based systems. In this contribution, we demonstrate the sensitivity of the OFDM system to phase noise effects by using a dynamic model for the CATV channel. We conclude by giving the specifications for a converter that should allow the DVB-T system to function in the CATV network
This paper presents an efficient blind symbol timing estimation scheme for orthogonal frequency-d... more This paper presents an efficient blind symbol timing estimation scheme for orthogonal frequency-division multiplexing (OFDM) systems with constant modulus constellation. The proposed technique is designed to estimate symbol timing offsets by minimizing the power difference between subcarriers with similar indices over two consecutive OFDM symbols based on the assumption that the channel slowly changes over time. The proposed power difference estimator (PDE) is totally blind because it requires no prior information about the channel or the transmitted data. Monte Carlo simulation is used to assess the PDE performance in terms of the probability of correct timing estimate Plock-in. Moreover, we propose a new performance metric denoted as the deviation from safe region (DSR). Simulation results have demonstrated that the PDE performs well in severe frequency-selective fading channels and outperforms the other considered estimators. The complexity of the PDE can be significantly reduced by incorporating a low-cost estimator to provide initial coarse timing information. The proposed PDE is realized using feedforward and early-late gate (ELG) configurations. The new PDE-ELG does not suffer from the self-noise problem inherent in other ELG estimators reported in the literature.
We introduce a new method to enhance the tolerability of the pilot based impulse noise canceller ... more We introduce a new method to enhance the tolerability of the pilot based impulse noise canceller presented in J. Rinne et al. (2002) in time and frequency selective environments. The method uses a quantized value of the carrier deviations caused by the presence of the impulsive interference to weight the soft bits in the digital terrestrial receiver. Hence more reliability against the impulse burst is achieved. The performance of the new method is compared to conventional receiver structures in different fading environments. Ricean and Rayleigh static channel cases are used to evaluate the system performance in bit error rate (BER) sense. Also a mobile channel case with moderate Doppler spread is considered.
This paper discusses the use of the autocorrelation method introduced in A. Hazmi et al. (2002) t... more This paper discusses the use of the autocorrelation method introduced in A. Hazmi et al. (2002) to cancel multi-tap loop interference with exponential profile in digital terrestrial broadcasting using relays. It was shown that the method can cancel efficiently the coupling between the transmitter and the receiver antennas in the relay station when one tap loop model is considered. Here we modify the autocorrelation method to deal with multi-tap loop with exponential profile. Analytical and experimental results are presented to verify the advantages and the limitations of the method in such environment. Bit error rate simulation results are also considered in AWGN and Rayleigh static channels cases
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