Multilevel Codes for Satellite Broadcasting under LMS Channels

Abstract

Abstract-We introduce the use of multidimensional (MD) constellations in a multilevel coding (MLC) scheme with multistage decoding (MSD) designed for broadcasting communications, where services with different quality of service (QoS) are desirable. We show that the number of different protection levels increases when using MD constellations. Besides, the appropriate block labeling (BL) partitioning for an MD constellation is found by applying the binary switching algorithm (BSA) as an efficient search algorithm. Two cost functions for the BSA are proposed based on the BL criterion. Some methods to construct an appropriate MD constellation are presented, including the use of uniform and non-uniform component constellations. The viability of the proposed MD constellations approach for broadcasting with different protection levels is evaluated analyzing the mutual information (MI) of each level. Finally, we present a comparison between a unidimensional and a multidimensional scheme which again demonstrates the benefits of the proposed scheme.

Effect of Satellite System Impairments on a Multilevel Coding System for Satellite Broadcasting

“…An MLC scheme suitable for satellite broadcasting communications has been proposed in [7] and further investigated in [8], where a typical bit-interleaved coded modulation (BICM) [9] scheme and an MLC scheme are compared. The MLC approach presents more flexibility when setting different levels of QoS, and the highly protected levels can operate at lower signal-to-noise ratios (SNRs) than the BICM approach.…”

“…In [7] and [8], a simple additive white Gaussian noise (AWGN) channel or a Land-Mobile-Satellite (LMS) channel model have been assumed, respectively. However, the impairments associated to satellite systems have not been taken into account so far.…”

“…SYSTEM MODEL MLC has been proposed for satellite broadcasting systems in [6] and [7], where only the effect of an AWGN channel has been analyzed. A more accurate channel description, based on 978-1-4244-8331-0/11/$26.00 ©2011 IEEE an LMS channel model [10], is considered in [8] to obtain more realistic performance results for MLC in a satellite broadcasting system. In this paper, we focus on different impairments associated to satellite communications: channel estimation errors, phase noise, and non-linearity of the satellite HPAs.…”