K-BAND LAND-MOBILE SATELLITE CHANNEL CHARACTERIZATION USING ACTS

K-band pilot tone data collected by the Advanced communications technology satellite (ACTS) mobile terminal (AMT) during 1994 are used to characterize the K-band land-mobile satellite channel. The characterization is twofold: a probability density model is derived which shows that the fade exceedance levels at K-band are much higher than those at lower frequencies, particularly at L-band. Furthermore, the fade statistics are very dependent on the geometry of the surrounding environment. The difference between good and bad environments is much more pronounced at K-band than at L-band. A discrete time model is used to provide insight into the bursty nature of the errors induced by propagation effects on the channel. For a data rate of 9600 bps, the average fade duration for a fade threshold of 6 dB is of the order of a few thousand bits, which corresponds to a fade duration of 2—5 ms. The fade durations are typical of those at L-band which suggests that whereas the K-band fades are more severe than those at L-band, the durations are approximately the same.