Author/Authors :
MOSTARI, Latifa University of Hassiba BENBOUALI - Faculty of Technology - Department of Electronics, Algeria , TALEB-AHMED, Abdelmalik University of Valenciennes and Hainaut Combrésis - LAMIH UMR CNRS 8201, France
Abstract :
Given the increasing number of applications requires high data transmission without increasing the channel bandwidth, this is the reason for the use of high order constellations such as QAM (Qaqdrature Amplitude Modulation). In order to eliminate inter symbols interferences, introduced for high data rate over multi-paths channels, with less complexity, we use OFDM (Orthogonal Frequency Division Multiplexing) Modulations. However, OFDM modulation using QAM requires a high signal to noise ratio. To overcome this disadvantage, it is interesting to combine high error correction codes such as LDPC codes with QAM using OFDM. Binary LDPC (Low-Density Parity-Check) code shows performance weakness when higher order constellations is used. To avoid this weakness, non-binary LDPC code is investigated. In this work, we show, under Gaussian, Rayleigh and Rician channels, with high order constellations (16-QAM, 64-QAM and 256 -QAM) using OFDM modulations, that binary LDPC code is a good errors correcting code. Also, we illustrate that its non-binary version, with highorder constellations, increases the system performance. We show that the performance of LDPC codes can be improved with the increasing of the iterations number.
NaturalLanguageKeyword :
LDPC codes , OFDM modulation , Gaussian channel , Rician channel , Rayleigh channel
