Method and apparatus for compensation of Doppler induced error in a mobile handset

1. A method for correcting for Doppler shift in signals at a mobile unit in communication with a base station comprising:

detecting a rate of change of position of the mobile unit in relation to the base station;

deriving a Doppler correction from a rate of change, wherein said deriving comprises determining a larger of a stored timer value and a current timer value,

wherein, if said larger of a stored timer value and a current timer value is the stored timer value, it is an indicia of acceleration and if said larger of a stored timer value and a current timer value is the current timer value, it is an indicia of deceleration; and

applying the Doppler correction to a timebase.

2. The method according to claim 1 , wherein the mobile unit is a dual band unit, further comprising:

using the Doppler correction to calculate the synchronization with the timebase of a second system when the mobile unit is operating in a network of a first system.

3. The method according to claim 1 , wherein said deriving a Doppler correction

is dependent upon: the speed of the mobile unit,

a direction of movement of the mobile unit with respect to closer to or farther from the base station,

selecting a larger timer value from a stored timer value and a current timer value,

and an interval since a last timebase synchronization.

4. The method according to claim 1 , wherein said change of position is detected by a change in timing advance value.

5. An apparatus for correcting for Doppler shift in signals at a mobile unit in communication with a base station comprising:

detecting a rate of change of position of the mobile unit in relation-to the base station,

means for deriving a Doppler correction from a rate of change, said means for deriving a Doppler correction comprising means for determining the larger of a stored timer value and a currently read timer value, determining a larger of a stored timer value and a current timer value,

wherein, if said larger of a stored timer value and a current timer value is the stored timer value, it is an indicia of acceleration and if said larger of a stored timer value and a current timer value is the current timer value, it is an indicia of deceleration; and

means for applying the Doppler correction to a timebase.

6. The apparatus according to claim 5 , wherein the mobile unit is a dual band unit, further comprising:

means for using the Doppler correction to calculate the synchronization with the timebase of a second system when the mobile unit is operating in a network of a first system.

7. An apparatus for correcting for Doppler shift in signals at a mobile unit in communication with a base station comprising:

a controller for detecting a rate of change of position of the mobile unit in relation to the base station;

a calculator for deriving a Doppler correction based in part on a rate of change, said calculator capable of determining a larger of a stored timer value and a currently read timer value,

wherein, if said larger of a stored timer value and a current timer value is the stored timer value, it is an indicia of acceleration and if said larger of a stored timer value and a current timer value is the current timer value, it is an indicia of deceleration; and

an applicator for applying the Doppler correction to a timebase.

8. The apparatus according to claim 7 , wherein the mobile unit is a dual band unit, and said apparatus further comprises means for using the Doppler correction to synchronize the mobile unit with the timebase of a second system when the mobile unit is operating in a network of a first system.