Asymptotic throughput of the FED-STD-1052 data link protocol

There has been a rapid evolution of data communication technologies specially adapted to the challenges of HF skywave channels. The 1980s saw the development of advanced HF modems that achieve significant processing gains through adaptive equalization and advanced coding. The standardized HF data link link protocol of FED-STD-1052 and MIL-STD-187-721C effectively uses the capabilities of these new modems to achieve reliable data delivery at rates well above those previously attainable. This paper presents a straightforward mathematical model for predicting the throughput of user data that can be achieved by the HF data link protocol (HFDLP) and the single-tone HF data modem over a wide range of channel conditions. This model is based upon measurements of modem performance, and is validated by measurements of protocol throughput. The model can be implemented in a spreadsheet so that HF system designers can easily predict and optimize the performance of their systems. Measurements of other popular HF protocols are included for comparison.