Abstract
The signal scintillation effects at UHF represent a significant design challenge for the future military mobile user objective system (MUOS) satellite communications. An adaptive soft output demodulator for GMSK signaling with very small value is investigated in MUOS narrowband applications. Without any performance loss, significant complexity reduction is achieved by using differential precoding, the Laurent (1986) signal representation and sampling the received symbols at the end of the symbol duration. The performance of the GMSK demodulator over six typical MUOS flat scintillation channels, particularly over the worst-case scintillation channel among them, are studied through simulations in both uncoded and convolutional coded systems.