Radio telephone and method for operating a radiotelephone in slotted paging mode
First Claim
1. A method for operating a Code Division Multiple Access (CDMA) radiotelephone in a slotted paging mode, the CDMA radiotelephone operable in a CDMA radiotelephone system, the method comprising the steps of:
- (a) determining a wakeup time;
(b) synchronizing a sleep clock signal to a received pseudorandom noise (PN) rollover boundary, thereby synchronizing the sleep clock signal with a system time of the radiotelephone system, and storing the system time and a future linear sequence generator (LSG) state;
(c) entering a sleep mode, interrupting communication;
(d) in the sleep mode, simulating system timing until end of the wakeup time; and
(e) resuming communication using the future LSG state.
4 Assignments
0 Petitions
Accused Products
Abstract
Prior to entry into a low-power sleep mode, a radiotelephone (104) in a radiotelephone system (100) calculates in advance the timing required to wake up selected portions of the radiotelephone and stores the calculated wakeup times in registers (216). Also prior to entry into sleep mode, local timing of the radiotelephone is synchronized to received PN roll boundaries from the radiotelephone system. In the sleep mode, the radiotelephone uses a sleep timer (210) to simulate system timing. When the sleep timer (210) matches the stored wakeup times, the radiotelephone re-activates the selected portions of the radiotelephone, such as an oscillator (116) and a radio frequency portion (109) of an analog front end (108), to exit the sleep mode and reacquire communication with the system. This also permits an early exit from sleep mode, for example to service an interrupt, while maintaining system timing.
119 Citations
17 Claims
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1. A method for operating a Code Division Multiple Access (CDMA) radiotelephone in a slotted paging mode, the CDMA radiotelephone operable in a CDMA radiotelephone system, the method comprising the steps of:
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(a) determining a wakeup time; (b) synchronizing a sleep clock signal to a received pseudorandom noise (PN) rollover boundary, thereby synchronizing the sleep clock signal with a system time of the radiotelephone system, and storing the system time and a future linear sequence generator (LSG) state; (c) entering a sleep mode, interrupting communication; (d) in the sleep mode, simulating system timing until end of the wakeup time; and (e) resuming communication using the future LSG state. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for operating a radiotelephone in a slotted paging mode in a Code Division Multiple Access (CDMA) radiotelephone system, the radiotelephone including a processor, a pseudorandom noise (PN) generator, and a receiver configured for communication with a base station, the method comprising the steps of:
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receiving a CDMA signal from the base station; identifying a wakeup time; detecting PN rollover boundaries in the CDMA signal; in response to a PN rollover boundary, resetting a sleep timer to synchronize the sleep timer with a system time; inactivating the processor, the PN generator, and the receiver, interrupting communication with the base station; generating local timing in response to a timing signal from the sleep timer to simulate system timing and synchronize local timing to the system time; when local timing corresponds to the wakeup time, activating the processor; aligning the PN generator to a current system time using a system timing offset; and upon reacquisition of the CDMA signal, resuming communication with the base station. - View Dependent Claims (8, 9, 10, 11)
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12. A radiotelephone operable in a slotted paging mode, the radiotelephone comprising:
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a modem for detecting pseudorandom noise (PN) roll boundaries in system timing; a call processor for controlling entry to a sleep mode by the radiotelephone, the call processor configured to calculate one or more wake up times for exiting the sleep mode; a timing controller including; registers for storing the one or more wakeup times; a sleep timer for generating local timing, the sleep timer synchronizing the local timing to system timing using the PN roll boundaries; a comparator for comparing local timing and the one or more wakeup times; and select logic for restarting portions of the radiotelephone when local timing matches a wakeup time. - View Dependent Claims (13, 14, 15)
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16. A method for operating a radiotelephone system which includes at least one base station and at least one radiotelephone, the method comprising the steps of:
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at a base station, maintaining a system time; transmitting a code division multiple access (CDMA) signal including periodically timed PN rollover boundaries; at a radiotelephone, receiving the CDMA signal; detecting the PN rollover boundaries in the CDMA signal; in response to a PN rollover boundary, resetting a sleep timer to synchronize local timing with the system time; inactivating a portion of the radiotelephone, interrupting communication with the base station; generating local timing to simulate system timing; when local timing corresponds to the wakeup time, activating the portion of the radiotelephone; aligning local timing to a current system time using a system timing offset; and upon reacquisition of the CDMA signal, resuming communication with the base station. - View Dependent Claims (17)
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Specification