Continuous phase modulation for the indoor wireless channel

Continuous phase modulation achieves a good power-bandwidth efficiency while maintaining a constant envelope signal. This research investigates the degradation in performance when a CPM system is operated over an indoor wireless channel that is characterized by slow frequency selective Rician fading and multiple cochannel interferers. The cochannel interferers operate with the identical modulation as the desired signal. Various magnitudes of interference powers and fading are examined.; The performance of a partially coherent receiver with interference is investigated and the ideal modulation index for minimum error performance is found. The optimum maximum likelihood test statistic is derived for operation in AWGN and is applied to the combined interference and multipath of an indoor channel. The probability of bit error is obtained for this maximum likelihood sequence estimating receiver. The error expression is a function of all possible trellis paths and the noise variance, averaged over the random components of the interference and fading. The noise variance is comprised of the AWGN and multipath components and an exact expression is derived for it, in order to study the error behavior.; Four candidate CPM modulation index values are plotted for various levels of multipath fading, number of interferers, and powers of the interferers. The Monte-Carlo numerical integration method is used to obtain the error performance for a larger number of interferers. Comparisons with the MC method and the regular numerical integrations are performed, to verify the validity of the results. The performance in fading with numerous multipaths is examined, using two models of the multipath profile; constant power and exponentially decaying. The error performance differences between the constant power and the exponentially decaying multipath profiles are discussed. A comparison of the CPM results to Gaussian filtered minimum shift keying (GMSK), a modulation in the Global System Mobile (GSM) international telecommunication standard and part of the CPM family of modulations, is performed. The superior probability of error performance of certain CPM indices is demonstrated.