PARALLEL INTERFERENCE CANCELLATION AND DETECTION OVER A LAND MOBILE SATELLITE CHANNEL

Abstract

A land mobile satellite communication channel has been modeled based on the physical phenomena of multipath fading and signal shadowing. This is used for software fading simulation. The most important parameter of this model is the time-share of shadowing S, ranging from less than 1% on highways to 89% in cities. A parallel interference cancellation scheme has been used for detection over the channel. A maximum-likelihood based multiuser channel estimation scheme requiring the transmission of a training sequence has been redesigned from an implementation perspective for reduced complexity. Once a composite channel-impulse response of each user is estimated, it is directly used in the estimation process instead of first extracting the individual channel parameters, such as path delays and attenuation factors. A reduced-complexity, bit-streaming multiuser detection algorithm •that avoids the need for multishot detection has been implemented. The system has been tested under different environments characterized by the shadowing parameter S.