Time synchronized networks of wireless nodes and the wireless nodes

Patent metadata

Field	Value
Publication number	US-10958249-B2
Application number	US-201916681675-A
Country	US
Kind code	B2
Filing date	Nov 12, 2019
Priority date	Feb 26, 2016
Publication date	Mar 23, 2021
Grant date	Mar 23, 2021

Abstract

A wireless network includes a tunable RF transmitter in wireless communication with a master node to transmit at a first slave frequency; a tunable RF receiver in wireless communication with the master node to receive at a second slave frequency; and an RF oscillator to communicate with the RF receiver and the RF transmitter an RF oscillator frequency to determine and tune the first and second slave frequencies. The RF oscillator is configured to receive calibration information including time information or frequency information, or both, from a reference node. The RF oscillator frequency of the RF oscillator is tuned based on the calibration information from the reference node to enable communication between the slave node and the master node at the tuned RF oscillator frequency.

First claim

We claim:

1. A wireless slave node for a wireless network system, comprising:
a tunable radiofrequency (RF) receiver configured to be in wireless communication with a master node and to receive at a slave frequency, the master node being configured to transmit at a master frequency;
an RF oscillator configured to communicate with the tunable RF receiver, the RF oscillator being configured to communicate an RF oscillator frequency to the RF receiver to determine and tune the slave frequency;
a signal processor configured to communicate with said tunable RF receiver;
wherein said signal processor is further configured to provide instructions to said tunable RF receiver to search for reception of a signal from said master node by tuning said slave frequency of said tunable RF receiver within a predetermined search band of frequencies, to provide an initial detected master frequency,
wherein said signal processor is further configured to instruct said tunable RF receiver to receive a calibration signal at said initial detected master frequency from said master node, said calibration signal containing time information or frequency information, or both,
wherein said signal processor is further configured to provide a frequency error of said RF oscillator frequency relative to said calibration signal by comparing information from said calibration signal to a corresponding signal from said RF oscillator to tune the RF oscillator frequency to the frequency of the master node to enable communication between said slave node and said master node at said tuned RF oscillator frequency, and
wherein said tunable RF receiver and said RF oscillator are structured as a single-chip semiconductor device on one semiconductor die.

2. The wireless slave node of claim 1 , wherein said RF oscillator comprises a relaxation oscillator circuit or a LC circuit, or both.

3. The wireless slave node according to claim 1 , wherein the slave node further comprises an antenna electrically connected to said tunable RF receiver.

4. The wireless slave node according to claim 1 , wherein said slave node further comprises a source of electrical energy in electrical connection with said tunable RF receiver and said RF oscillator to power said slave node, and
wherein said source of electrical energy comprises an energy scavenging structure that extracts energy from a local environment of said wireless slave node.

5. The wireless slave node according to claim 4 , further comprising an energy storage structure in electrical connection with said source of electrical energy.

6. The wireless slave node according to claim 1 , further comprising a memory device configured to communicate with said signal processor to store said tuned RF oscillator frequency.

7. The wireless slave node according to claim 1 , further comprising a tunable RF transmitter configured to be in wireless communication with said master node and to transmit at a slave frequency.

8. The wireless slave node according to claim 7 , wherein said slave frequency of said tunable RF receiver is substantially the same as said slave frequency of said tunable RF transmitter.

9. The wireless slave node according to claim 8 , wherein the RF oscillator comprises a first RF oscillator configured to communicate with the tunable RF receiver and a second RF oscillator configured to communicate with the tunable RF transmitter, the first and second RF oscillators being configured to communicate frequency information to the tunable RF transmitter and to the tunable RF receiver to determine and tune the slave frequency of the tunable RF receiver and the slave frequency of the tunable RF transmitter.

10. The wireless slave node according to claim 1 , wherein said signal processor is further configured to compute a frequency error of said RF oscillator by comparing information from said calibration signal from said master node to a corresponding signal from said RF oscillator to calculate a communicating frequency that more closely matches said master frequency than said initial detected master frequency.

11. The wireless slave node according to claim 1 , wherein the slave node further comprises a local clock configured to communicate with said tunable RF receiver to provide timing information to said tunable RF receiver.

12. The wireless slave node according to claim 11 , wherein the local clock is configured to receive a calibration signal from the master node, said calibration signal containing time information or frequency information, or both, to tune the local clock to a master clock of the master node.

13. The wireless slave node according to claim 11 , wherein the local clock comprises a low frequency oscillator having a lower frequency than the RF oscillator frequency of the RF oscillator.

14. The wireless slave node according to claim 1 , wherein said calibration signal contains at least two beacon signals transmitted from the master node to the slave node at two distinct points in time.

15. A method of tuning a communication frequency of a slave node to a communication frequency of a master node, the master node comprising a master radio frequency (RF) transmitter configured to transmit at a master frequency, the master frequency being generated by the master node using a master clock, the method comprising:
searching, by the slave node, for reception of a signal from the master node by tuning a slave frequency of a tunable RF receiver of the slave node within a predetermined search band of frequencies to provide an initial detected master frequency, the slave frequency corresponding to an RF frequency provided by an RF oscillator in the slave node;
receiving, by the slave node, a calibration signal at the initial detected master frequency from said master node, the calibration signal containing time information or frequency information, or both;
determining, by the slave node, a frequency error between the calibration signal containing the time information or frequency information, or both, and the slave frequency; and
tuning, by the slave node, the slave frequency to the frequency of the master node based on the frequency error to enable communication between the slave node and the master node at the tuned slave frequency.

16. The method according to claim 15 , wherein determining the frequency error between the calibration signal and the slave frequency comprises computing a frequency error of said RF oscillator by comparing information from the calibration signal from the master node to a corresponding signal from the RF oscillator to calculate a communicating frequency that more closely matches the master frequency than the initial detected master frequency.

17. The method according to claim 15 , wherein tuning the slave frequency to the frequency of the master node comprises correcting for the frequency error between the calibration signal and the slave frequency.

Assignees

• Univ California

Inventors

• Khan Osama
• Pister Kristofer

Classifications

• H04W56/0035 Primary

  detecting errors in frequency or phase · CPC title

• H04W84/20

  Leader-follower arrangements · CPC title

• H04W56/0015

  one node acting as a reference for the others · CPC title

• H04L7/00

  Arrangements for synchronising receiver with transmitter {(synchronisation of generators of electric oscillations or pulses H03L7/00)} · CPC title

• H03J1/0025

  in a remote control unit (remote control tuning in general H03J9/00) · CPC title