Quaternary LDPC Codes on OFDM Systems

This paper evaluates the performance of quaternary LDPC codes associated to OFDM systems. The LDPC codes are based on a ring Z4 of integers modulo-4. Each OFDM subcarrier is modulated using a 4-PSK modulation, and each output symbol of the encoder is mapped onto that modulation. The performance is evaluated, in terms of BER versus Eb/N0, for AWGN and frequency-selective fading channels. The results show good performance when compared to the channel encoding process of the Brazilian Digital Television System (SBTVD).