Power Control of Turbo Coded System in Rayleigh Fading Channel

Sung-Joon PARK  

IEICE TRANSACTIONS on Communications   Vol.E90-B   No.1   pp.144-147
Publication Date: 2007/01/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e90-b.1.144
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Fundamental Theories for Communications
power control,  turbo code,  power truncation,  channel estimation error,  

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We propose reallocating the power resource among the code symbols in such a way to minimize the post decoding error probability of turbo code. We consider several power reallocation policies and investigate their performance in slowly-varying Rayleigh flat fading channel. We show that the proposed scheme can reduce the post decoding error probability by two orders of magnitude and provide a power gain of 0.86 dB at BER=10-6 over the traditional equal power allocation among all code symbols. We also propose applying different power levels and cut-off thresholds on systematic and parity check bits depending on the channel gain, and investigate the effect of channel gain estimation error.