Adaptive resource sharing as a fade countermeasure for satellite radio networks

With increasing frequency the atmospheric attenuation of radio waves on Earth-space paths increases mainly because of absorption due to rain. To achieve operation of a 20/30-GHz satellite link with a high level of transmission quality, therefore, an effective measure to counteract distortion due to attenuation has to be established. Instead of implementing a high rain fade margin at each station, a fade countermeasure strategy is proposed combining up-link power control (UPC) and adaptive resource sharing (ARS) by allocating a common satellite-based back-up capacity to a link suffering from attenuation. Implementation of the common resource can be realised rather effectively within a TDMA network by allocating an extra time slot to the link(s) affected by attenuation. This additional time interval is used for transmission of redundant coding bits or for enabling utilisation of a lower transmission bit rate to meet the required transmission quality in case of degraded carrier-to-noise ratio. By proper allocation of the required resource with respect to the current attenuation level, economic use of the expensive satellite capacity can be obtained.