Patent ID: 11917569
Assignee: LANDIS+GYR TECHNOLOGY, INC.
Field: Digital communication (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A method performed by an endpoint device in a mesh network for adjusting a frequency of a crystal oscillator of the endpoint device, the method comprising:
while operating in an initial communication mode,
receiving a reference timing signal over a mesh network from a reference device in the mesh network, wherein the reference device is synchronized to a clock with a frequency of higher accuracy and stability than the frequency of the crystal oscillator;
obtaining a current value of a frequency of the crystal oscillator of the endpoint device;
determining a frequency difference between a reference frequency of the reference timing signal and the current value of the frequency;
generating a control signal based on the frequency difference;
adjusting the frequency of the crystal oscillator according to the control signal; and
determining that an error of the frequency of the crystal oscillator satisfies a pre-determined condition;

in response to determining that an error of the frequency of the crystal oscillator satisfies a pre-determined condition, switching to a narrowband or ultra-narrowband communication mode, wherein a data rate of the narrowband or ultra-narrowband communication mode is lower than a data rate of the initial communication mode; and
transmitting to and receiving communication signals from another device in the mesh network using an oscillating signal generated by the crystal oscillator while operating in the narrowband or ultra-narrowband communication mode.