LDPC coded adaptive transmission over fading channels

Alireza Kobravi*, Mohammad Shikh-Bahaei, Mohamed Slim Alouini, Apostolos Georgakis

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Scopus citations


This paper first develops a simple closed form expression for the bit error rate (BER) of low density parity check coded (LDPC) M-ary quadrature amplitude modulation (MQAM) signals as a function of the signal constellation, received signal to noise ratio (SNR), and LDPC code parameters. Based on this new expression, joint optimization of the SNR target and transmission rate is studied for LDPC coded MQAM signals to maximize the average spectral efficiency (ASE) subject to an average transmit power constraint over Rayleigh flat fading channels. Total or truncated channel-inversion strategies are exploited for the inner-loop power control, since data rate and outer-loop SNR target are adapted either to coded BER (CBER) or to the SNR with instantaneous CBER constraint. It is shown that the use of BER-based adaptation instead of SNR-based adaptation is even more beneficial in coded systems than in un-coded systems in terms of ASE performance. Indeed some of our numerical examples show that adaptation based on CBER has up to 2-2.5 dB power saving over SNR-based adaptation on the ASE of coded systems.

Original languageEnglish (US)
Title of host publicationWCNC 2008 - IEEE Wireless Communications and Networking Conference, Conference Proceedings
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages6
ISBN (Print)9781424419968
StatePublished - 2008
Externally publishedYes
EventIEEE Wireless Communications and Networking Conference, WCNC 2008 - Las Vegas, NV, United States
Duration: Mar 31 2008Apr 3 2008

Publication series

NameIEEE Wireless Communications and Networking Conference, WCNC
ISSN (Print)1525-3511


OtherIEEE Wireless Communications and Networking Conference, WCNC 2008
Country/TerritoryUnited States
CityLas Vegas, NV

ASJC Scopus subject areas

  • General Engineering


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