1 research outputs found
Unequal Error Protection by Partial Superposition Transmission Using LDPC Codes
In this paper, we consider designing low-density parity-check (LDPC) coded
modulation systems to achieve unequal error protection (UEP). We propose a new
UEP approach by partial superposition transmission 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
analyzed by using discretized density evolution. Also proposed in this paper 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 (AWGN) channels and uncorrelated Rayleigh fading channels, 1)
UEP-by-PST provides higher coding gain for the MID compared with the
traditional equal error protection (EEP) approach, but with negligible
performance loss for the LID; 2) UEP-by-PST is more efficient with the proposed
practical criterion than the UEP approach in the digital video broadcasting
(DVB) system