Fatma Rouissi

Coupling interface circuit design for experimental characterization of the narrowband power line communication channel

This paper presents the design of an appropriate coupling interface circuit for measuring indoor power line transmission channel characteristics in CENELEC/FCC/ARIB low-frequency bands. This coupling circuit prevents the powerful and damaging 50 Hz/220 V current from entering sensitive measurement equipments while allowing narrowband PLC signals reception. It also guarantees impedance matching and instruments protection from very large voltage spikes and fast transients. Tests following EN 50065-2-3 standard [1] are done to verify that the proposed coupling interface provides a high safety level and is in compliance with immunity requirements.

Precoded OFDM for power line broadband communication

In this paper we investigate high data rate communication over Power Line Channel (PLC). PLC model is based on multipath propagation which leads to considerable magnitude degradations in some frequency ranges. This gives rise to the well known phenomena of spectral nulls. Conventional coding schemas fail in recovering data in such an environment and several new methods are proposed to improve Bit Error Rate (BER) performance. In our work, the use of precoding technique to combat the power line channel spectral nulls is investigated, we show that the channel transfer function could be decomposed in two terms with no spectral nulls. The precoding gain is then analysed.

Adaptive technique for impulsive noise cancellation in broad-band power line communication system

The object of this work is to address impulsive noise cancellation for digital broadband power line communication scheme. This paper presents details of impulsive noise model based on its statistical properties and defined broadband OFDM technique. By adding a noise power (SINR) estimator a new adaptive noise canceller based on Matsuo algorithm is proposed. Presented simulation results show that the new proposed adaptive technique permits an improvement, not only in BER, but also in reducing processing time and so implementation complexity of the noise canceller.

Impulsive Noise Modelling Using Markov Chains in Indoor - Environment - Comparison With Stochastic Model

The object of this work is to investigate measurements and modelling of impulsive noise over in-house power lines. This paper presents details of impulsive noise characteristics determined from experiments. Statistical study helps to propose a noise model based on Markov theory. The comparison of the model, first to measures, and secondly to a previous validated model, prove the validation of the proposed Markov model to be used for optimizing transmission schemes.

Low amplitude impulsive noise in vehicular power line network

Low amplitude impulsive noise measurements have been carried out in the time domain on a vehicle power line network. These measurements were made on a stationary vehicle and the motor idling. The characteristics of the measured low amplitude pulses were studied in terms of amplitude, frequency, duration and time interval between successive pulses. Stochastic models based on mathematical distribution functions and fitting the experimental distribution of the various pulse characteristics are proposed.

Performances of switching algorithm methods in MIMO-OFDM systems

In this paper, we propose two methods to perform a switching between spatial multiplexing and MIMO diversity in order to improve performances of a 2×2 OFDM-MIMO system. Each method is defined depending on the granularity of the spatial processing. The comparison of BER performances of the two schemes leads to the choice of the sub-carrier based switching processing which gives the most significant improvement.

Impulsive noise cancellation based on zero insertion technique for high bit rate powerline communication system

This paper presents a technique for maintaining good broadband transmission quality in the face of impulsive noise in OFDM- PLC systems. The proposed technique is based on adding one zero between two signal samples in order to estimate the noise power in every transmitted signal sample. Simulation results of complete PLC system highlight good improvement in BER and correction ability performances for low power noise pulses independently from its types and durations.

Improvement technique of channel estimation in OFDM-MIMO systems

This paper presents an extra processing added to conventional LS estimation to improve its performances in OFDM-MIMO systems. The new technique is based on the knowledge of the power delay profile. The application of the improved estimator is useful when employing advanced MIMO adaptation techniques such switching algorithms and leads to significant improvement in decision criterion precision and consequently in terms of BER.

RS turbo codes with erasures for broad-band power line communication

This paper presents a novel coding procedure to correct error bursts generated by impulsive noise corruption in broad-band PLC systems. The coding technique is based on a turbo code structure that uses RS coding and hard decision iterative decoding with erasure process in the decoder. The application of the new coding technique instead of simple RS in the HomePlug 1.0 FEC stage leads to significant improvement in terms of BER.

Adaptive beamforming technique combined to ppSNR based switching in multi-user MIMO systems

This paper investigates adaptive Beamforming techniques used in concatenation with a ppSNR-based switching algorithm in multi-user MIMO OFDM systems. The performances equivalence of SM adaptive beamforming and STBC adaptive one is shown analytically and by simulation, and a complexity study is carried out and allows selecting the beamforming adapted to SM. The effect of the MIMO architecture (with or without Eigen modes selection) is also explored when the switching algorithm is combined to SM adaptive beamforming, and simulation results leads to significant improvement in terms of BER in comparison with MIMO diversity and spatial multiplexing when applied separately.