Multilevel codes show better performance compared with trellis codes o
n Rayleigh fading channels at comparable decoder complexity and bandwi
dth. However, they suffer from performance degradation due to error pr
opagation in the multistage decoder. The authors, with a view to minim
ising the error propagation, compare three multilevel coded 16-QAM sch
emes which are four-level codes, I/Q separated two-level codes and I/Q
separated two-level codes with a new set partitioning.