Multilevel coded FSK/PSK modulation

In this paper, based on the multilevel coding and multistage decoding techniques, new multilevel systems are introduced for 2FSK/4PSK modulation. This type of modulation is very suitable for multilevel coding due to the large Euclidean distance at the first step of the mapping by the set partitioning method. The proposed systems are compared to the Padovani and Wolf´s 2FSK/4PSK trellis codes (1986) in terms of asymptotic coding gains, decoding complexities, decoding delays and it is shown that our systems have error performance and decoding complexity advantages. We also give a generalized error weight profile expression for the multilevel coded schemes.