Effect of satellite system impairments on a multilevel coding system for satellite broadcasting

In this paper, we evaluate a multilevel coding (MLC) scheme with multistage decoding (MSD) designed for satellite broadcasting communications. The impact of three different satellite system impairments on the decoding performance is analyzed. First, the influence of errors introduced by the channel estimation is discussed, assuming a typical data-aided (DA) channel estimator with different pilot lengths. Second, the impact of the residual phase noise present after the phase recovery is investigated using a model based on a normal distribution. Finally, the degradation introduced by the non-linearities of the satellite power amplifiers is also analyzed. The impact of these effects is investigated via the mutual information. Besides, bit error rate (BER) simulations are performed for each impairment effect. The considered MLC scheme is compared to a classical bit-interleaved coded modulation (BICM) scheme, showing that the MLC scheme provides different grades of robustness for each level

Window design for non-orthogonal interference reduction in OFDM receivers

For conventional orthogonal frequency-division multiplexing (OFDM) systems, the guard interval is disregarded in the receiver and rectangular shaped windows are used implicitly due to the discrete Fourier transform (DFT). We consider a Nyquist-shaped window in the receiver, so that the transmit signal does not need to be modified, and optimize the window shape in order to suppress interference from non-orthogonal single carrier interferer signals. For the window coefficients, a closed form solution is derived. This type of interference usually occurs in OFDM radio systems like Digital Radio Mondiale (DRM) that are operating in low frequency bands. (Disturbance is given for instance by harmonics of switched-mode power supplies.)

Single carrier interference cancellation for digital radio mondiale (DRM)

We consider cancellation of a single carrier interferer for the Digital Radio Mondiale (DRM) system. The interferer is fully described by its frequency, amplitude, and phase. These parameters can be estimated in a maximum-likelihood sense using the pilot symbols in the orthogonal frequency division multiplexing (OFDM) signal. Subsequently, the interference may be reconstructed and subtracted from the received signal. Alternatively, the knowledge of the interferer frequency may be exploited for the design of a notch filter, nulling out the interference. Results show that the reconstruction and substraction method outperforms the notch filtering approach only if an accurate estimate of the interferer frequency is available. Otherwise, notch filtering has better performance

Minimum Probability of Error-Based Equalization Algorithms for Fading Channels

Novel channel equalizer algorithms are introduced for wireless communication systems to combat channel distortions resulting from multipath propagation. The novel algorithms are based on newly derived bounds on the probability of error (PE) and guarantee better performance than the traditional zero forcing (ZF) or minimum mean square error (MMSE) algorithms. The new equalization methods require channel state information which is obtained by a fast adaptive channel identification algorithm. As a result, the combined convergence time needed for channel identification and PE minimization still remains smaller than the convergence time of traditional adaptive algorithms, yielding real-time equalization. The performance of the new algorithms is tested by extensive simulations on standard mobile channels