Power-Efficient Adaptive-and-Robust Link OFDM (PEARL-OFDM)

Key obstacles to extending OFDM to wireless links and networks at high-frequencies and dynamic channels are inherent low performance to Doppler and power amplifiers operation with high back-off. Other significant obstacles are multipath and impulsive noise. PEARL-OFDM combines a layered architecture with technologies that mitigate such obstacles and enable full-range rates that maximizes connectivity, add unparallel robustness to Doppler over dynamic channels, has inherent robustness to narrowband fading and impulsive noise that drastically reduces “adaptation rates” and maximizes connectivity, and achieves near-optimum power conditioning of typical variable envelope signals enabling power amplifiers operation at saturation. PEARL provides a solid infrastructure for incremental addition of relevant capabilities including TRANSEC and LPD/LPI. For this, PEARL integrates two chirp OFDM technologies with different Truly Shift Orthogonal Codes (TSOC): one with randomly chirped codes and intrinsic TRANSEC characteristics dedicated to “variable rates” and another with linearly chirped codes and intrinsic robustness to Doppler. A novel Split-Phase Shift-Keying modulation overlay “makes’ resulting OFDM signals suitable for saturated power amplifiers. Applied Radar proposes to design, develop and simulated the performance of the combined PEARL technologies during Phase I, and develop a software-define-radio testbed and demonstrate PEARL’s performance over relevant military channels during Phase II.