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Spectrum efficient A/J waveform for 21st century HF communications

The concept of spectrum efficient, anti-jam (A/J), high frequency (HF) communications is discussed. The HF concept is intended for mobile, beyond line of sight (BLOS) military communications for use in the 21st century. Spectrum efficiency and fast frequency hopping offer opportunities for high data rates and A/J capability. This system concept is referred to as HF 4 21. The concept employs a new high density modulation waveform-discrete trellis-coded modulation (d-TCM), Reed-Solomon code, and fast frequency hopping (3 or 6 kilohops/s), to achieve: high spectrum efficiency, frequency reuse, and A/J. These features are desirable for future army tactical communications, but unachievable in a single system with current HF technology. The technical feasibility and system performance are also presented.