Patent ID: 8509721

Claim:
A method of non-linear frequency control tracking of a control loop of a voltage controlled oscillator (VCO) in a wireless mobile device receiver, the method comprising: determining a channel metric based on one or more channel quality indicators determined from a received radio frequency channel and is a function of one or more channel quality indicators selected from a signal-to-noise ratio of the received channel, bit-error rate of the received channel, a received signal strength measurements, and carrier-to-interference-plus-noise ratios (C/I+N) wherein each of the one or more channel quality indicators has an associated weighting in determining the channel metric; determining a state metric associated with the current operating state of the control loop, the state metric comprises a function of a frequency error between the frequency of the received radio frequency channel and an output frequency of the VCO and at least one of: a weighted function of the current channel metric; and one or more previous operating state metrics weighted by a time parameter, wherein the time parameter decreases the weighting of the previous operating state metric; determining one or more state metric threshold values associated with the determined channel metric, the one or more state metric threshold values selected from a plurality of state metric threshold values each associated with a transition to a possible operating state of the control loop, from the current operating state; determining if one of the one or more state metric threshold values has been exceeded based upon the determined state metric, wherein the state metric threshold values is defined for each transition between each of operating states; transitioning from the current operating state to the operating state associated with the exceeded state metric threshold value; and providing at least one coefficient to an adaptive loop filter of the control loop, the at least one coefficient associated with the transitioned operating state: wherein the state metric threshold values associated with the operating states provide overlapping region between common operating states to provide hysteresis for operating state transitions.