Finite Mixture Distributions

Orthogonal frequency division multiplexing (OFDM) is a technique used for terrestrial digital video broadcasting (DVB-T) and many other modern applications. The longer OFDM symbol duration provides an advantage in a presence of weak impulsive noise, because impulsive noise energy is spread among simultaneously transmitted OFDM sub-carriers. However, it has been recently recognized that this advantage turns into a disadvantage if the impulsive noise energy exceeds certain threshold. In this paper the algorithm for impulsive noise suppression in OFDM receivers is proposed and investigated. Whereas traditional methods for impulsive noise suppression are implemented in a time domain before OFDM demodulation, proposed algorithm compensates impulsive noise in a frequency domain after OFDM demodulation and channel equalization. The method is applied to DVB-T and its performance is studied by means of simulation.

Impulsive noise suppression in OFDM-based communication systems

Non-parametric likelihood based channel estimator for Gaussian mixture noise

This paper presents an efficient technique to jointly mitigate the severe bit error rate (BER) performance degradation caused by impulsive noise (IN) and multipath fading in broadband transmission systems The proposed system is based on a low complexity interleaving process applied after the inverse fast Fourier transform (IFFT) in orthogonal frequency division multiplexing (OFDM) systems, hence it is denoted as time-domain interleaving (TDI) The proposed TDI introduces both time and frequency diversity, which can be used to effectively combat impairments such as IN and frequency-selective fading In addition to its substantial BER reduction capability, the TDI does not degrade the spectral efficiency and has low computational complexity In frequency-selective fading channels, the BER of the proposed system is mathematically equal to that of Walsh-Hadamard precoded OFDM systems [1] In presence of IN, analytical and simulation results show that TDI can remarkably reduce the level of the error floors that are commonly observed Specifically, TDI can achieve a BER of 10-5 for less than 1 dB difference from the IN-free case

BER Reduction of OFDM Based Broadband Communication Systems over Multipath Channels with Impulsive Noise

Cubic phase function

This paper proposes a suitable method for simulating impulses with appropriate amplitude, spectral, and inter-arrival characteristics. The statistics used to develop the parameters of this model are based on statistics derived from observations of impulse noise on the telephone networks of British Telecom (BT) and Deutsche Telekom (DT). This paper initially reviews the former DT approach to impulse noise generation for testing digital subscriber line systems, so called xDSL systems. Some problems are highlighted and an alternative technique is suggested that is capable of generating impulses with both appropriate amplitude an spectral characteristics.

I. Mann

Papers

Impulse generation with appropriate amplitude, length, inter-arrival, and spectral characteristics