Title :
Variable LDPC coding rate performances for multicarrier systems using HD decoding
Author :
Cances, J.-P. ; Meghdadi, V.
Author_Institution :
ENSIL Univ. of Limoges, France
Abstract :
An adaptive coding scheme minimising the BER of a bit-interleaved coded modulation OFDM system performing hard-decisions (HD) after the demodulation and ideal interleaving is proposed. The subcarrier code rate levels subject to a rate constraint are varied according to perfect channel state information at the transmitter. The derived adaptive scheme uses low-density parity-check codes. A modified bit-flipping algorithm provides HD decoding and can be applied either alone or combined with a power loading scheme. It is shown by Monte Carlo simulations that, for broadband systems with Rayleigh fading, the loading procedure provides a signal-to-noise ratio gain up to 3dB for an average BER level of 10-5.
Keywords :
Monte Carlo methods; OFDM modulation; Rayleigh channels; adaptive codes; broadband networks; channel coding; decision theory; decoding; demodulation; error statistics; interleaved codes; modulation coding; parity check codes; variable rate codes; BER; BICM; LDPC; Monte Carlo simulation; OFDM system; Rayleigh fading; adaptive coding scheme; bit error rate; bit-flipping algorithm; bit-interleaved coded modulation; broadband system; demodulation; hard-decision decoding; low-density parity-check code; multicarrier system; orthogonal frequency division multiplexing; perfect channel state information; power loading scheme; transmitter; variable rate codes;
Journal_Title :
Communications, IEE Proceedings-
DOI :
10.1049/ip-com:20045320