| CPC H04W 52/0229 (2013.01) [H04W 72/0453 (2013.01)] | 32 Claims |
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1. A method of operating a wireless device operative in a wireless communication network, comprising a primary receiver circuit and a low-power wakeup receiver, the method comprising:
suspending operation of the primary receiver circuit to conserve power;
operating the low-power wakeup receiver circuit;
receiving one or more wakeup signals transmitted by the network;
down-converting the one or more wakeup signals using an uncalibrated local oscillator signal;
demodulating and decoding the down-converted one or more wakeup signals;
extracting frequency related information from the decoded one or more wakeup signals;
using the extracted frequency related information to correct the local oscillator signal frequency;
receiving subsequent wakeup signals transmitted by the network in a frequency hopping pattern, wherein each wakeup signal includes information related to the frequency location of a subsequent wakeup signal;
using the frequency-corrected local oscillator signal to down-convert subsequent wakeup signals transmitted by the network;
performing narrowband filtering on the down-converted, subsequent wakeup signals and
demodulating and decoding the filtered, down-converted, subsequent wakeup signals.
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