TITLE:
Opportunistic Error Correction for OFDM-Based DVB Systems
AUTHORS:
Xiaoying Shao, Cornelis H. Slump
KEYWORDS:
DVB-T2; LDPC; BCH; Convolutional; Reed-Solomon Codes; OFDM; Fountain Codes
JOURNAL NAME:
Communications and Network,
Vol.5 No.4,
November
28,
2013
ABSTRACT: DVB-T2 (second generation terrestrial digital video
broadcasting) employs LDPC (Low Density Parity Check) codes combined
with BCH (Bose-Chaudhuri-Hocquengham) codes, which has a better performance in
comparison to convolutional and Reed-Solomon codes used in other OFDM-based
DVB systems. However, the current FEC layer in the DVB-T2standard is still not
optimal. In this paper, we propose a novel error correction
scheme based on fountain codes for OFDM-based DVB systems. The key
element in this new scheme is that only packets are processed by the receiver
which has encountered high-energy channels. Others are discarded. To achieve a
data rate of 9.5 Mbits/s, this new approach has a SNR gain of at least 10 dB with perfect
channel knowledge and 11 dB with non-perfect channel knowledge in
comparison to the current FEC layer in the DVB-T2standard. With a
low-complexity interpolation-based channel estimation
algorithm, opportunistic error correction offers us a QEF (Quasi
Error Free) quality with a maximum DF (Doppler Frequency) of 40 Hz
but the current DVB-T2 FEC layer can only provide a BER of 10?7 quality after BCH decoding with a maximum DF of 20 Hz.