A turbo-coded hybrid ARQ for low earth orbit microsatellite communications

A proposed turbo-coded hybrid ARQ designed for improving the throughput of UoSAT/SSTL LEO microsatellite downlink communications is presented. The flexibility and robust error correcting capability of turbo codes are incorporated adaptively into the existing ARQ protocol. The proposed scheme optimizes the increment of coding parity and schedules the decoding iterations to take place during intervals between microsatellite passes. Simulations show a remarkable improvement over the existing protocol, giving more than 84% gross throughput or 69% net throughput at channel bit error rate of 5 x 10(-3), whereas with the current protocol the throughput would be close to zero. Copyright (C) 1999 John Wiley & Sons, Ltd.