Patent ID: 11943713
Assignee: TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
Field: Digital communication (Electrical engineering)
Classification: CPC H  Y | IPC H

Claim 8:
9. A wireless device operative in a wireless communication network comprising:
a primary receiver circuit adapted to be suspended to conserve power;
a low-power wakeup receiver circuit adapted to receive and process one or more wakeup signals transmitted by the network, the wakeup receiver circuit comprising:
a digitally controlled oscillator adapted to generate a local oscillator signal;
a mixer receiving the local oscillator signal and the received one or more wakeup signals and adapted to frequency down-convert the received one or more wakeup signals;
a filter downstream of the mixer; and
a digitization and digital processing circuit downstream of the filter and adapted to demodulate and decode the one or more wakeup signals and extract frequency related information from the decoded one or more wakeup signals;

wherein the wakeup receiver is adapted to:
use the extracted frequency related information to correct the local oscillator signal frequency;
use the frequency-corrected local oscillator signal to frequency down-convert subsequent wakeup signals transmitted by the network;
perform narrowband filtering on the down-converted subsequent wakeup signals; and
demodulate and decode the filtered, down-converted, subsequent wakeup signals;

wherein the wakeup signals are transmitted on a frequency hopping pattern to minimize interference and each wakeup signal includes information related to a frequency location of a subsequent wakeup signal;
wherein each wakeup signal encodes data indicating the frequency of a carrier signal on which it was transmitted, and wherein the digital processing circuits are adapted to extract frequency related information from the received wakeup signals by decoding the carrier signal frequency data.