Title :
Shaping gain for AWGN channel by non-uniform constellation in LDPC-Coded system
Author :
Xiaoqing Wang ; Fu, Jian ; Wang, Xiaoqing ; Pan, Changyong ; Yang, Zhixing
Author_Institution :
Dept. of Electron. Eng., Tsinghua Univ., Beijing, China
Abstract :
It is commonly believed that there is a gap between the channel capacity and the highest achievable rate of equiprobable uniform constellation. To achieve shaping gain, non-uniform constellation following a Gaussian distribution has been designed for the AWGN channel and discussed widely along with Turbo codes. In this paper, we investigate the effect of non-uniform constellation and propose a scheme to achieve shaping gain for AWGN channel and also multipath channel using low density parity check (LDPC) codes with different rates of 0.40.6 and 0.8. Simulation results show that, non-uniform 64-QAM or 8-PAM can offer shaping gain of approximately 0.23 dB for LDPC coding rate of 0.6 over AWGN channel in DTMB system.
Keywords :
AWGN channels; Gaussian distribution; channel capacity; channel coding; multipath channels; parity check codes; pulse amplitude modulation; quadrature amplitude modulation; turbo codes; AWGN channel; DTMB system; Gaussian distribution; LDPC-coded system; PAM; QAM; Turbo codes; channel capacity; low density parity check codes; multipath channel; AWGN channels; Channel capacity; Constellation diagram; Digital video broadcasting; Error correction codes; Gaussian distribution; Multimedia communication; Parity check codes; TV broadcasting; Turbo codes;
Conference_Titel :
Communication Systems, 2008. ICCS 2008. 11th IEEE Singapore International Conference on
Conference_Location :
Guangzhou
Print_ISBN :
978-1-4244-2423-8
Electronic_ISBN :
978-1-4244-2424-5
DOI :
10.1109/ICCS.2008.4737393
