Importance

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Abstract

Reduced current drain is effected by cycling off non-essential circuits within the radiotelephone during periods of inactivity. The period of inactivity is dynamically allocated using data update messages sent over the analog control channel. Each data update message consists of an update index and a data message. The mobile radiotelephone receives the update index to determine if there has been any change to the data message. If there has been no change to the message, the mobile radiotelephone turns off non-essential circuits during the duration of the data message. In this manner, the mobile radiotelephone may be quiescent for as long as the data message, e.g., 20 words, or 950 milliseconds of each full second. This corresponds to a 5% duty cycle. The duration of the quiescent period allows components with a slow response time, such as the frequency synthesizer, to be deactivated further reducing battery drain. The length of the data message may also be dynamically changed to optimize stand-by time relative to paging activity.

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First Claim