Assessment of a gateway switching algorithm for Q/V-band smart diversity systems in the Q/V-LIFT project

The exploitation of Q/V-band will boost the capacity of High-Throughput Satellites (HTS) but, on the other side, it will prompt the adoption of innovative techniques, such as Smart Gateway Diversity (SGD) to cope with heavy propagation impairments. In this paper, feeder link operation is simulated assuming that an N+P SGD system (i.e. N active gateways and P backup gateways) is adopted to mitigate rain fades. Due to the non-negligible latency (~30 s) involved by gateway handover, a linear predictor of rain attenuation has been designed to operate before the switching decision block. In a gateway cluster (N = 9 and P = 1) with mid-latitude gateway stations, the above SGD set-up leads to a feeder link availability of about 99.66% of time with a small degradation compared to the case in which the attenuation is exactly known (99.79%). However, the number of predicted handovers significantly increases to an average of about 1200 events per year, which may result in critically short separations between consecutive events. The crucial trade-off involved is between number of handovers and probability to miss a fade.