Unequal error protection by partial superposition transmission using low-density parity-check codes

• Published in: IET communications Vol. 8; no. 13; pp. 2348 - 2355
• Main Authors: Huang, Kechao, Liang, Chulong, Ma, Xiao, Bai, Baoming
• Format: Journal Article
• Language: English
• Published: Stevenage The Institution of Engineering and Technology 01.09.2014; John Wiley & Sons, Inc
• Subjects: additive white Gaussian noise channels; AWGN channels; channel coding; Channels; codeword; Criteria; Density; Digital Video Broadcasting; digital video broadcasting system; discretised density evolution; Error correcting codes; error correction codes; error statistics; Errors; Gaussian; information sequence; LDPC coded modulation systems; less important data; LID; low density parity check; MID; Modulation; modulation coding; more important data; parity check codes; partial superposition transmission; Rayleigh channels; UEP approach; UEP‐by‐PST system; uncorrelated Rayleigh fading channels; unequal error protection; less important data; discretised density evolution; modulation coding; unequal error protection; error correction codes; channel coding; codeword; UEP-by-PST system; parity check codes; LID; Rayleigh channels; MID; low density parity check; LDPC coded modulation systems; UEP approach; partial superposition transmission; information sequence; AWGN channels; uncorrelated Rayleigh fading channels; digital video broadcasting; digital video broadcasting system; additive white Gaussian noise channels; more important data; error statistics
• ISSN: 1751-8628; 1751-8636; 1751-8636
• DOI: 10.1049/iet-com.2013.1168

In this study, the authors consider designing low-density parity-check (LDPC) coded modulation systems to achieve unequal error protection (UEP). They propose a new UEP approach by partial superposition transmission (PST) called UEP-by-PST. In the UEP-by-PST system, the information sequence is distinguished as two parts, the more important data (MID) and the less important data (LID), both of which are coded with LDPC codes. The codeword that corresponds to the MID is superimposed on the codeword that corresponds to the LID. The system performance can be analysed by using discretised density evolution. Also proposed in this study is a criterion from a practical point of view to compare the efficiencies of different UEP approaches. Numerical results show that, over both additive white Gaussian noise channels and uncorrelated Rayleigh fading channels, (i) UEP-by-PST provides higher coding gain for the MID compared with the traditional equal error protection approach, but with negligible performance loss for the LID; and (ii) UEP-by-PST is more efficient with the proposed practical criterion than the UEP approach in the digital video broadcasting system.