Dynamic temperature compensation and stage selection in pilot signal acquisition

A temperature compensated pilot searcher, comprising:

• a temperature sensor for measuring the temperature of a mobile phone;
• means for periodically measuring the frequency of a mobile phone local oscillator;
• a temperature compensation table for storing the measured local oscillator frequencies corresponding to the measured mobile phone temperature;
• a temperature array of lesser size than the temperature compensation table for storing the measured local oscillator frequencies corresponding to the measured mobile phone temperature;
• wherein a most recent measured frequency overwrites a first location corresponding to the same temperature if said first location exists or wherein the most recent measured frequency and a most recent measured temperature overwrite corresponding oldest locations of frequency and temperature if said first location does not exist;
• means for calculating an estimated frequency at an arbitrary temperature based upon the previously saved values in the temperature compensation table and the temperature array;
• wherein the estimated frequency is equal to a frequency value in the temperature array at the arbitrary temperature if that location exists or wherein the estimated frequency is equal to a weighted sum of a frequency value in the temperature compensation table at the arbitrary temperature plus the frequencies in the temperature array at temperatures within a predetermined distance from the arbitrary temperature;
• a plurality of pilot searcher stages;
• means for activating one of the plurality of pilot searcher stages based upon the estimated frequency.

A method of choosing a pilot searcher stage within a wireless communication device comprising:

• measuring a current temperature;
• estimating a local oscillator frequency at the measured temperature, the estimating involving:
• (a) defining a temperature compensation table having locations for storage of a frequency entry for each of a plurality of temperature settings;
• (b) defining a temperature array, containing less elements than the temperature compensation array, having a plurality of locations for the storage of frequency readings corresponding to temperature settings;
• (c) measuring periodically a frequency of a local oscillator and a device temperature;
• (d) writing the value of the measured frequency into the temperature compensation table;
• (e) writing the value of the measured frequency into a least current location in the temperature array or into a location within the temperature array corresponding to the same temperature when the location exists;
• (f) estimating the local oscillator frequency at a particular temperature to be a frequency saved in the temperature array at the particular temperature when that temperature exists in the temperature array;
• and
• (g) when the temperature does not exist, estimating the local oscillator frequency at the particular temperature to be a weighted sum of the frequency stored in the temperature compensation table at the particular temperature and the frequencies in the temperature array at temperatures within a predetermined distance from the particular temperature;
• calculating a frequency error based upon the estimated local oscillator frequency and a predetermined receive frequency;
• and
• choosing one of a plurality of pilot searcher stages based upon the value of the calculated frequency error.