Rapid acquisition concept for voice activated CDMA communication

Rapid initial acquisition and rapid reacquisition are crucial for successful voice activated code division multiple access (CDMA) communication, posing a challenging problem if frequency uncertainties due to Doppler and/or local oscillator instabilities are expected. A maximum likelihood acquisition concept, using a novel receiver structure, is shown to meet these requirements. Signal-to-noise ratio and receiver operating characteristic considerations show the advantages of swiveling matched filter receivers. The performance of the suggested acquisition concept is evaluated by computing the time required to acquire the desired CDMA signal with 99% probability. The applicability of hard-limiting digital matched filters is briefly discussed