Serial Concatenation of LDPC and Turbo Code for GPRS System under Different Fading Channels

Abstract

In wireless communication systems, error control coding is necessary to provide reliable communications over fading channels. Turbo code is used practically in third generation due to good error correcting capability. However, it has error floor at high signal-to-noise ratio (SNR). Concatenation of another code as an outer code is an alternative to reduce turbo codepsilas error floor. In this paper, we study the behavior of a general packet radio service (GPRS) system, under different scenarios. We propose a method for reducing transmitter energy versus bit error rate and eliminating the error floor via a serial concatenation of low density parity check (LDPC) and turbo codes instead of the convolutional coded system. Moreover, computer simulations were conducted to compare the overall system performances obtained with turbo coding to the serial concatenation coded and channel non coded systems. The performance of the coding scheme is discussed in a Rayleigh fading channel with correlated and non correlated fading amplitudes and an additive white Gaussian noise (AWGN). Evaluation of the proposed encoder has shown a performance improvement over fading channels.