Parallel acquisition of multicarrier direct-sequence spread-spectrum signals in fading and partial-band interference

The frequency diversity of multicarrier direct-sequence signaling can potentially offer robust performance in frequency-selective channels. The paper focuses on the acquisition of multicarrier signals in channels containing fading and partial-band interference. The maximum-likelihood decision rule for parallel acquisition in frequency-selective fading and partial-band interference is derived. Several simpler, near-optimal decision rules are also discussed. The performance of these decision rules is compared to that of equal-gain combining for multicarrier acquisition. Results show that the decision rules designed specifically for partial-band interference give significantly better performance. Methods of acquisition with a limited number of correlators are also discussed. Finally, the potential benefits of estimating the signal strength on each subcarrier prior to acquisition are examined.