Oezdemir, Mehmet; Eliacik, A. Burak; Guenes, Ismail; Sasioglu, A. Betuel (National Research Institute of Electronics and Cryptology, Bilgem – Tuebitak, Gebze, Kocaeli, Turkey)
High frequency data communication has its own typical characteristics. In this type of communication, free space is used as transmission medium and data is carried with electromagnetic radio waves to beyond-line-of-sight. Comparing with guided media types such as metallic/fiber-optic cables, or higher frequency radio waves, HF’s bandwidth is considerably low. Also, HF radio waves are subjected to various types of noise and highly affected environmental changes. Hence, HF data communication requires special network protocols. STANAG 5066 is such a data link protocol which is designed to carry information efficiently between two or more HF nodes throughout the air. DMP is an application layer protocol and its objective is to transfer time-critical e-mails over several types of network at low bandwidths. In this paper, we discuss HF radio protocol stack implementations which involve DMP and STANAG 5066 for time-critical e-mail transfers. We compare usage of DMP over reliable and unreliable STANAG 5066. Also, we propose a “fragment size change” algorithm for DMP in order to enhance its usage over unreliable bearers for multicast and EMCON messages at high error rates.