An adaptive equalizer for reliable transmissions in DVB-S2 satellite communications under ISI

This paper presents a proposal of an Adaptive Equalizer based on DFE, and its implementation in FPGA, to make DVB-S2 transmission reliable under ISI (specially for wideband transmissions) and to make possible the mobile reception over satellite links for QPSK modulation. The Equalizer also presents the potential to reduce the nonlinear distortion effects, which are typically found in the satellite link and is caused by the satellite power amplifiers. This mainly affects high order modulations. The implementation is very flexible because it can make use of CMA and DD algorithms as well as the DVB-S2 header and embedded pilots as training sequences. Its adaptation is performed using the LMS algorithm. The paper presents the proposed architecture and algorithms, the VHDL simulations for AWGN channels and ISI, and the FPGA implementation resource usage. This is the initial step towards an implementation in VLSI.