Frequency hopped transmission with packet combining for satellite and terrestrial packet radio networks

A frequency-hopped spread spectrum packet radio network is considered. Instead of discarding the received packets which were unsuccessfully decoded, the receiver keeps and combines all received copies of the same packet to improve the throughput and reduce the delay necessary to transmit a packet successfully. It is shown that the throughput is substantially increased over a similar system where the uncorrectable packets are discarded. This system is equivalent to a fast frequency-hopped system where the diversity level is adapted according to the channel conditions. Reed-Solomon codes are used for error correction and detection. Exact analysis is given for calculating the symbol error probability and throughput when several copies of a symbol are combined together in the presence of multiple access interference. (Author)