Use of HF for extended-range Combat Net Radio (CNR) communications

In recent years military forces have become more mobile to meet contemporary mission requirements, and are frequently required to cover much larger geographic areas. As a result, they frequently outrun the transmission range of traditional VHF and UHF line-of-sight communication systems. Similar issues can arise in non-military situations such as border security, drug interdiction, or natural disaster response. An emerging solution to the range problems is the use of HF radios for extended-range Combat Net Radio (CNR) applications. HF signals have the ability to propagate to and over the horizon using either sky wave or ground wave modes. This unique ability has allowed HF radio to address the coverage gaps not served by VHF/UHF radio and other Beyond Line of Sight (BLOS) media. A key issue to be considered when designing and using an HF radio network for this purpose is that of network traffic capacity, due to the delivery latency and transmission overhead of HF voice communications waveforms and techniques. This paper discusses this issue and presents some potential solutions.