Performance of a synchronous ALE system on several short range HF links

This paper details the design, simulation, implementation, and on-air testing of a prototype synchronous ALE system which has been developed at Harris Corporation. This ALE system utilizes extremely robust burst serial tone waveforms to perform all channel linking, frequency evaluation, and link termination functions. The prototype system has been used as a test-bed to both measure the robustness of the waveforms and to explore a number of different linking techniques. A number of linking techniques have been examined including a single channel 3-way link set up (LSU) as well as a number of different multi-channel techniques. The multi-channel techniques include calling on the next available frequency, calling on a specified frequency, calling on the best frequency (with implied channel sounding) and calling on the first frequency to provide a specified level of performance. The paper begins with a discussion of the advantages and disadvantages of synchronous ALE systems or networks. This is followed by an explanation on the methods utilized to generate the presented results, both software simulation and on-air testing. Next is a discussion of the burst serial tone waveform utilized by the prototype system, including simulated performance. This is followed by the presentation of a simple single frequency link-set-up (LSU) technique. Simulated and on-air performance data is presented for this technique. Next, the operation of the synchronous, multi-channel ALE system is presented, along with some on-air performance data. The paper concludes with a summation of the results.