The spectral/power emciency and performance of the π/4-QPSK modems (American and Japanese digital cellular emerging standards)is studied and briefly compared to GMSK modems(proposed for European DECT and GSM cellular standards).Improved filtering strategies and digital pilot aided (digital channel sounding)techniques are considered for π/4-QPSK and for other digital modems.More spectrally efficient modem trends and UC Davis research results for future cellular/mobile(land mobile)and satellite communication systems applications are also highlighted.
展开▼
