PARQ-a system supporting information networking over HF radio links

The use of narrowband HF as a medium for information transfer in a networked environment has traditionally been viewed as limited due to the inherent problems of relatively high bit-error rates and low data throughputs. This paper provides a description of the Physical-layer Automatic Repeat reQuest (PARQ) protocol which addresses these two fundamental problems. Errors in delivered data are effectively eliminated by the ARQ component of the protocol, while the throughput is maximised by selecting the optimal raw channel data rate. Details of PARQ´s design parameters and implementation are given along with initial laboratory and field testing results. The paper concludes with a brief discussion of future system enhancements