Wakeup Receiver and Wakeup Signal Transmission

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.

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
• 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.

A base station operative in a wireless communication network, comprising:

• a transceiver;
• and
• processing circuitry operatively connected to the transceiver, and adapted to
• generate one or more wakeup signals, each including information related to a transmission frequency;
• and
• transmit the wakeup signals, each wakeup signal being transmitted on a corresponding carrier, on a frequency hopping pattern to increase robustness against interference, wherein each wakeup signal includes information related to the frequency location of a subsequent wakeup signal.