In this article, block and convolutional coding for Gaussian minimum shift keying (GMSK) in additive white Gaussian noise (AWGN) channels is investigated. The performance improvement that can be obtained without an increase in bandwidth is found for block and convolutional codes with various block lengths and constraint lengths, respectively, when a simple suboptimal demodulation scheme is used. For a fixed system transmission bandwidth, the tradeoff between the percentage of bandwidth to use for coding and the percentage to use for modulation is examined and optimized for various values of bandwidth.

Unequal error-protection (UEP) codes that are designed using trellis-coded modulation (TCM) are proposed for use with a single data stream consisting of information with two levels of importance. To achieve UEP, the proposed scheme encodes the data according to the importance of the information by switching between two codes which use different signal constellations. Using simple trellis codes, it is shown that the error rate of the important information is lower than the error rate for an equivalent equal error-protection scheme.

In this paper, the problem of signal design for continuous phase modulation is examined. Using the performance measures of effective bandwidth and minimum distance, "optimal" signal shapes are calculated for various receiver observation intervals for full and partial response signalling. For the partial response case, the optimization could only be done for receiver observation interval of one symbol due to the difficulty of the optimization. Therefore, a family of signals based on previously calculated optimal signals is introduced. The tradeoffs that result between bandwidth and bit error rate are then compared as a function of the receiver observation interval and as a function of the memory length of the signalling scheme. Then, the signals introduced in this paper are compared to well known signals in terms of their effective bandwidth-minimum distance tradeoffs, power spectra and percent-in-band-power. The signals obtained by the optimization process are found to have good spectral properties in relation to well known signals.>