Development and application of M-ary Gaussian minimum phase shift keying modulation

GMSK´s narrow spectrum and constant envelope account for its widespread acceptance in the cellular market. However, the current GMSK modulation exhibits two major flaws: (1) the ISI associated with GMSK´s multiple-symbol pulse shape necessitates complex processing at the receiver; and, (2) the lack of a higher-order version of GMSK precludes incorporation of bandwidth-efficient coding to enhance link quality. This paper describes a technique used to improve BER performance of GMSK on fading and non-fading channels, and realize high-order GMSK. The availability of high-order GMSK enables the combination of constant-envelope modulation with trellis-coded modulation schemes specifically designed to operate on fading channels