Use of ALE and packet radio for HF networks

The paper includes a brief description of current ALE (automatic link establishment) and packet radio techniques. ALE integrates selective calling, automatic linking, and link quality analysis to provide reliable `telephone-like´ service for HF voice and data users. Standardization and federal acceptance have recently been accomplished through the release of MIL-STD-188-141A and FED-STD-1045. In contrast, packet radio has evolved from line-of-sight applications, and its use on HF links has been pioneered by the amateur radio community. The authors focus on the use of packet radio and MIL-STD-188-141A techniques in HF networks. Many of the shortcomings of existing fixed channel HF packet radio systems can be overcome by the use of the robust ALE waveform described in the MIL-STD. Receive scan and selective call are shown to be effective tools for contacting both individual and multiple network members. Design examples are given. Packet structures are described which will support higher level network functions, such as internetting, routing, and store-and-forward switching. The areas currently under consideration for standardization in the higher level FED-STD-104X documents are discussed