An efficient form of error control coding applied to HF skywave links

The author describes the design and performance of an efficient data transmission protocol for use on low data rate (150 baud) HF skywave links. The protocol maximises data throughput by adjusting the amount of redundancy in transmissions to suit the channel conditions, using the technique of parity re-transmission. Little redundancy is added when few errors occur during transmission, but more is added when conditions deteriorate, enabling errors to be corrected. It is well suited to links where errors are bursty, and long error free paths (a sequence of consecutive bits where no bit is in error) exist, but will also operate when errors occur randomly.<
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