Pragmatic unequal error protection coded schemes for satellite communications

Unequal error protection designs based on multilevel coded modulation are presented for digital satellite transmission. Due to channel nonlinearity, the signal constellations chosen must have constant envelope, so that signaling schemes derived from PSK should be used. Four schemes of limited complexity are chosen for investigation. They are based on the same “pragmatic” approach used by Viterbi et al. (see IEEE Commun. Magazine, vol.27, no.7, p.11-19, July 1989). Their performance is analyzed over the AWGN and Rician fading channel. An asymptotic analysis based on a modified transfer function and dealing with different bit classes is proposed. The schemes found to be asymptotically best are further studied by simulation to assess their performance at intermediate bit error rates