Correction of timing errors to enable long sleep times
AssigneeMarvell International Ltd.
InventorsDaniel Yellin, Ronen Mayrench, Yona Perets
Life of this patent
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Abstract
A mobile user equipment includes a user equipment clock and a dual mode time tracker. The clock periodically wakes up the user equipment. The dual mode time tracker uses a serving cell reference signal to correct timing errors of the user equipment clock with respect to a network clock while timing errors remain minimal and otherwise uses a serving cell synchronization signal to correct timing errors of the user equipment clock. The dual mode time tracker also sets a next wakeup time as a function at least of the size of the timing errors.
Claims18
A method for synchronizing a user equipment clock in a cellular telecommunications user equipment, the method comprising:
- periodically waking up the user equipment to receive signals transmitted on a cellular telecommunications network;
- selecting a synchronization mode to synchronize the user equipment clock to a network clock, based at least on one or more signals received by the user equipment while the user equipment is awake to receive signals in a first instance, wherein a first synchronization mode uses a first type of signals and a second synchronization mode uses at least a second type of signals that is different from the first type of signals;
- in response to selecting the first synchronization mode to synchronize the user equipment clock to the network clock, in a second instance that is subsequent to the first instance, waking up the user equipment for a first period of time to receive signals;
- and
- in response to selecting the second synchronization mode to synchronize the user equipment clock to the network clock, in the second instance that is subsequent to the first instance, waking up the user equipment for a second period of time to receive signals, such that the second period of time is different from the first period of time.
A user equipment comprising:
- a clock configured to generate a clock signal and periodically wake up the user equipment to receive signals transmitted on a cellular telecommunications network;
- and
- a dual mode time tracker configured to select a synchronization mode to synchronize the user equipment clock to a network clock, based at least on one or more signals received by the user equipment while the user equipment is awake to receive signals in a first instance, wherein a first synchronization mode uses a first type of signals and a second synchronization mode uses at least a second type of signals that is different from the first type of signals,
- wherein the clock is further configured to, in a second instance that is subsequent to the first instance,
- (i) in response to the selection of the first synchronization mode, wake up the user equipment for a first period of time to receive signals, and
- (ii) in response to the selection of the second synchronization mode, wake up the user equipment for a second period of time to receive signals, such that the second period of time is different from the first period of time.
Dependencies are inferred from the claim text.