A. Vandana, C. Lisa, Nehru College of Engineering and Research Centre, Pampady, Thrissur.
DOI : 01.0401/ijaict.2014.01.19
International Journal of Advanced Information and Communication Technology
Received On : June 12, 2014
Revised On : July 20, 2014
Accepted On : August 15, 2014
Published On : September 05, 2014
Volume 01, Issue 05
Pages : 098-102
Abstract
Here an energy-efficient approach is presented for constellation shaping of a bit-interleaved low-density parity-check (LDPC) coded amplitude phase-shift keying (APSK) system. APSK is a modulation consisting of several concentric rings of signals, with each ring containing signals that are separated by a constant phase offset. APSK offers an attractive combination of spectral and energy efficiency, and is well suited for the nonlinear channels. A subset of the interleaved bits output by a binary LDPC encoder is passed through a nonlinear shaping encoder. An iterative decoder shares information among the LDPC decoder, APSK de-mapper, and shaping decoder. Information rates are computed for a discrete set of APSK ring radii and shaping bit probabilities, and here the additive white Gaussian noise (AWGN) channel is considered. In this paper, an adaptive equalizer is added in the iterative decoding path and its purpose is to reduce inter symbol interference to allow recovery of the transmit symbol. An adaptive equalizer one that automatically adapts to time-varying properties of the communication channel. The combination of shaping, use of LDPC codes, iterative decoding and with adaptive equalizer we can achieve a gain in excess of 1.18 dB in AWGN compared with a system that does not use shaping, uses an un optimized code from the DVB-S2 standard, and does not iterate between decoder and demodulator.
Keywords
APSK, LDPC, BICM-ID, DVB-S2, AWGN, Adaptive equalizer.
Cite this article
A. Vandana, C. Lisa, “A Review of Constellation Shaping and BICM-ID of LDPC Codes for DVB-S2 Systems” INTERNATIONAL JOURNAL OF ADVANCED INFORMATION AND COMMUNICATION TECHNOLOGY, pp.098-102, September 05, 2014.
Copyright
© 2014 A. Vandana, C. Lisa. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.