A new efficient ARQ scheme for satellite communications

A new efficient ARQ scheme, Virtual Multiple Data Links (VMDL), is proposed which is based on the philosophy of the go-back-N ARQ. In a go-back-N system, the transmitting side does not wait for a response after sending a data block, but instead immediately sends successive new data blocks. However, as soon as there is a NAK, or a time out caused by the absence of either a NAK or a ACK, the transmitting side immediately stops sending new data blocks in order to retransmit the previous N data blocks. As a result of the retransmission of these N data blocks, the communication throughput efficiency is eroded. On satellite channels, in particular, where the data transmission rate is high and the round trip delay is large, the communication throughput efficiency deteriorates rapidly as the error rate of the channel increases. The aim of the VMDL protocol is to meet the following functional requirements on satellite communications: to establish and terminate plural logical connections; provide a reliable data communications with a simple method to implement recovery procedure for transmission errors; conform to a commonly used international standards, especially CCITT X.25/X.75; and to achieve a high data transmission efficiency on high speed and large round trip delay circuits such as those in satellite communications