Robust Acquisition of Hybrid Direct Sequence-Slow Frequency Hopping Spread-Spectrum under Multi-Tone and Gaussian Interference in Fading Channels

This paper proposes new techniques for acquisition of hybrid DS-SFH spread-spectrum systems in the presence of partial-band interference in fading channels. The proposed techniques include differential detection followed by maximizing the circular cross correlation with a known PN sequence. This is extremely robust against tone interference. An interference rejection method is used to improve the performance for interference with high power and small bandwidth occupancy by detecting anomalies in metric amplitudes caused by peaked interference and eliminating such metrics from the decision process. Finally, an adaptive method is used to select the best processing for either Gaussian or tone interference. The performance of the proposed acquisition techniques are compared to the conventional FH acquisition technique in AWGN and fading channels and superior performance is demonstrated for narrowband Gaussian and multi-tone interference.