TY - GEN
T1 - LDPC coded adaptive transmission over fading channels
AU - Kobravi, Alireza
AU - Shikh-Bahaei, Mohammad
AU - Alouini, Mohamed Slim
AU - Georgakis, Apostolos
PY - 2008
Y1 - 2008
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=51649127221&partnerID=8YFLogxK
U2 - 10.1109/wcnc.2008.23
DO - 10.1109/wcnc.2008.23
M3 - Conference contribution
AN - SCOPUS:51649127221
SN - 9781424419968
T3 - IEEE Wireless Communications and Networking Conference, WCNC
SP - 100
EP - 105
BT - WCNC 2008 - IEEE Wireless Communications and Networking Conference, Conference Proceedings
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - IEEE Wireless Communications and Networking Conference, WCNC 2008
Y2 - 31 March 2008 through 3 April 2008
ER -