METHOD AND APPARATUS FOR ACQUIRING AND TRACKING PILOTS IN A CDMA COMMUNICATION SYSTEM

摘要

Techniques to acquire and track pilots in a CDMA system. In an aspect, frequency acquisition of a number of signal instances (i.e., multipaths) in a received signal may be achieved concurrently based on a frequency control loop (RAFC) maintained for each finger processor of a rake receiver. Upon successful acquisition, frequency tracking of acquired multipaths may be achieved based on a combination of a frequency control loop (VAFC) maintained for an oscillator used for downconverting the received signal and the RAFCs for the finger processors. In a tracking mode, the VAFC tracks the average frequency of the acquired multipaths by adjusting the frequency of the oscillator. The RAFC of each finger processor tracks the residual frequency error (e.g., due to Doppler frequency shift) of the individual acquired multipath by adjusting the frequency of a complex sinusoidal signal used in a rotator within the finger processor.