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

Key obstacles to extending OFDM to wireless links and networks at high frequencies with dynamic channels are inherent low performance to Doppler and power amplifier operation with high backoff. Other significant obstacles are multipath and impulsive noise. PEARL provides a solid communications infrastructure with support for incremental relevant capabilities including TRANSEC and LPD/LPI. For this, PEARL integrates two layers of 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 layer"makes"resulting OFDM signals suitable for saturated power amplifiers. PEARL-OFDM multi-layer architecture enables full-range rates that maximizes connectivity, adds unparalleled robustness to high-rate Doppler, has inherent robustness to narrowband fading and impulsive noise and achieves near-optimum power conditioning of typical variable envelope signals enabling power amplifiers operation at near saturation. In Phase I Applied Radar designed, developed the algorithms and simulated the performance of the combined PEARL technologies. In Phase II we will build a software-define-radio testbed including channel emulators, port algorithms, demonstrate the PEARL practical feasibility and performance and initiate its transition to an actual JTRS radio platform.