Patent ID: 6804503
Filing Date: 2004-10-12
Classification: H04W,Y02D

Abstract:
A system for operating a battery operated communication device with reduced power consumption wherein the communication device is adapted to receive radio signals containing intermittently scheduled digital messages, the communication device comprisingreceiver means for frequency downconversion of said radio signals and demodulation of said digital messages; a dual mode timer for continually maintaining system time while operating in one of two modes, said modes comprising an active mode and a sleep mode; controller data processing means for data processing of the demodulated message data to extract the messages; a reference oscillator for generating a reference clock, wherein the frequency of said reference clock is high enough to serve as clocking requirements for digital processing in the receiver and controller during the active mode, and wherein the frequency of said reference clock is responsive to input of an automatic frequency control word to the reference oscillator; a sleep oscillator for generating a frequency which is low relative to the frequency of the reference clock and wherein power consumption of the sleep oscillator is very low relative to the power consumption of the reference oscillator; and controller means for supervising operation of the communication device, wherein said supervision is executed by a microprocessor operation with program memory contained in a storage register, the controller means including: controller scheduling means for scheduling commands for supervision of the communication device, event scheduler means for receiving scheduling commands, the event scheduler means including registers for records of scheduled events, each scheduled event comprising a command word that initiates a processing event and the scheduled system time for execution of said command, the event scheduler continually monitoring system time for a match with the scheduled time in any of the records, said match causing execution of the command in the record for which the match occurs; and controller frequency tracking means for providing for automatic frequency control wherein received downconverted signals are processed to generate a frequency control word for the reference oscillator at the rate of once per message reception such that the frequency of the reference oscillator clock is frequency-locked to the received signal.