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A method and apparatus of assigning fingers in a rake receiver for incorporation in a receiver of a CDMA communications system is disclosed herein. The method includes measuring the multipath profile of a received spread-spectrum radio-frequency (RF) signal to obtain a sequence of measurements, iden

A method and apparatus of assigning fingers in a rake receiver for incorporation in a receiver of a CDMA communications system is disclosed herein. The method includes measuring the multipath profile of a received spread-spectrum radio-frequency (RF) signal to obtain a sequence of measurements, identifying the best candidate path of the RF signal to demodulate by determining which measurement within the sequence has the highest signal strength, deriving a timing offset for the best candidate path as a function of the measurement for the best candidate path and its adjacent measurements, and assigning a finger processing element to the best candidate path using the derived timing offset. The measurements are taken using a searcher having a predetermined timing resolution (e.g., 1/2 chip), and the resolution of the timing offset is higher (e.g., 1/8 chip). The best candidate path to demodulate is identified using the measurement having the highest amplitude or correlation function. The function used to derive the timing offset is a quadratic passing through the measurement for the best candidate path and adjacent measurements. A correction factor can be applied to the estimated timing offset to correct for non-quadratic multipath profiles. The assignment can be made for an available finger, or a finger can be re-assigned where the best candidate path is better than a path currently being demodulated. This approach can also be used to update and instantaneously adjust the timing of fingers to track on-time samples of the received multipaths during operation of the rake receiver.

대표청구항 ▼

[ I claim:] [1.]1. A method of assigning finger processing elements in a rake receiver for use in a CDMA communications system, comprising the steps of:receiving a spread-spectrum radio-frequency (RF) signal having a plurality of multipath signal components forming a multipath profile;measuring the

[ I claim:] [1.]1. A method of assigning finger processing elements in a rake receiver for use in a CDMA communications system, comprising the steps of:receiving a spread-spectrum radio-frequency (RF) signal having a plurality of multipath signal components forming a multipath profile;measuring the multipath profile of the RF signal to obtain a sequence of measurements, wherein adjacent measurements within the sequence are separated by a predetermined timing resolution, and each measurement has an amplitude indicative of signal strength;identifying the best candidate path of the RF signal to demodulate by determining which measurement within the sequence of measurements has the highest signal strength;deriving a timing offset for the best candidate path as a function of at least the measurement for the best candidate path and the measurements adjacent thereto, wherein the derived timing offset has a resolution higher than the predetermined timing resolution; andassigning a finger processing element of the rake receiver to the best candidate path using the derived timing offset.