Signal strength-based routing of network traffic in a wireless communication system

Patent metadata

Field	Value
Publication number	US-9286787-B2
Application number	US-201414338592-A
Country	US
Kind code	B2
Filing date	Jul 23, 2014
Priority date	May 27, 2004
Publication date	Mar 15, 2016
Grant date	Mar 15, 2016

Abstract

A low cost, robust, wireless sensor that provides an extended period of operability without maintenance is described. The wireless sensors are configured to communicate with a base unit or repeater. When the sensor unit detects an anomalous ambient condition (e.g., smoke, fire, water, etc.) the sensor communicates with the base unit and provides data regarding the anomalous condition. The sensor unit receives instructions to change operating parameters and/or control external devices.

First claim

What is claimed is:

1. A method of routing communication traffic in a wireless sensor system, comprising:
measuring a signal strength of wireless signals received by a first wireless repeater unit from one or more wireless sensor units, one or more wireless base units, and one or more other wireless repeater units;
wirelessly communicating, from the first wireless repeater unit, a first message indicative of the signal strengths measured by the first wireless repeater unit;
updating, at a second wireless repeater unit and based on the first message, a first list comprising wireless sensor units with which the second wireless repeater unit can communicate;
measuring a signal strength of wireless signals received by the second wireless repeater unit from one or more wireless sensor units, one or more wireless base units, and one or more other wireless repeater units;
wirelessly communicating, from the second wireless repeater unit, a second message indicative of the signal strengths measured by the second wireless repeater unit;
updating, at the first wireless repeater unit and based on the second message, a second list comprising wireless sensor units with which the first wireless repeater unit can communicate;
relaying, by the first wireless repeater unit, in accordance with the second list, a first sensor measurement made by a first wireless sensor unit of the one or more wireless sensor units, by transmitting a third message that comprises the first sensor measurement in encrypted form, an address portion, an integrity portion comprising a checksum, and an authentication portion for use in verifying authenticity of the third message, wherein relaying the first sensor measurement comprises:
analyzing, by the first wireless repeater unit, the authentication portion to verify the authenticity of the third message;

ignoring, by the second wireless repeater unit, in accordance with the first list, the first sensor measurement made by the first wireless sensor unit;
relaying, by the second wireless repeater unit, in accordance with the first list, a second sensor measurement made by a second wireless sensor unit of the one or more wireless sensor units, by transmitting a fourth message that comprises the second sensor measurement in encrypted form, an address portion, an integrity portion comprising a checksum, and an authentication portion for use in verifying authenticity of the fourth message, wherein relaying the second sensor measurement comprises:
analyzing, by the second wireless repeater unit, the authentication portion to verify the authenticity of the third message; and

ignoring, by the first wireless repeater unit, in accordance with the second list, the second sensor measurement made by the second wireless sensor unit.

2. The method of routing communication traffic in a wireless sensor system of claim 1 , wherein the first and second wireless repeater units respectively communicate the first and second messages only once, without retransmitting the first and second messages.

3. The method of routing communication traffic in a wireless sensor system of claim 1 , further comprising causing the first and second wireless repeater units to respectively communicate the first and second messages as part of respective periodic transmissions.

4. The method of routing communication traffic in a wireless sensor system of claim 3 , further comprising:
causing the first wireless repeater unit to delay communicating the first message by a first random delay time, and
causing the second wireless repeater unit to delay communicating the second message by a second random delay time.

5. The method of routing communication traffic in a wireless sensor system of claim 1 , further comprising causing each of the first and second wireless repeater units to, prior to respectively communicating the first and second messages:
determine whether a radio frequency channel is in use;
transmit the message over the radio frequency channel when it is determined that the radio frequency channel is not in use; and
switch to a different radio frequency channel when it is determined that the radio frequency channel is in use.

6. The method of routing communication traffic in a wireless sensor system of claim 1 , further comprising:
causing the first wireless repeater unit to retransmit the first message until the first wireless repeater unit receives a first acknowledgement message, and
causing the second wireless repeater unit to retransmit the second until the second wireless repeater unit receives a second acknowledgement message.

7. The method of routing communication traffic in a wireless sensor system of claim 1 , further comprising causing, for each of the first and second wireless repeater units, the wireless repeater unit to include an identifier of the wireless repeater unit in messages communicated by the wireless repeater unit.

8. The method of routing communication traffic in a wireless sensor system of claim 7 , wherein the first message includes the identifier of the first wireless repeater unit and the second message includes the identifier of the second wireless repeater unit.

9. A method of routing communication traffic in a wireless communication system, comprising:
measuring a signal strength of wireless signals received by a first wireless repeater unit from one or more wireless sensor units, one or more wireless base units, and/or one or more other wireless repeater units;
wirelessly communicating, from the first wireless repeater unit, a first message indicative of the signal strength measured by the first wireless repeater unit;
measuring a signal strength of wireless signals received by a second wireless repeater unit from one or more wireless sensor units, one or more wireless base units, and/or one or more other wireless repeater units;
wirelessly communicating, from the second wireless repeater unit, a second message indicative of the signal strength measured by the second wireless repeater unit;
selecting routing paths for communication within the wireless communication system based on the first message and the second message;
relaying, by the first wireless repeater unit, based on the selected routing paths, a first sensor measurement made by a first wireless sensor unit of the one or more wireless sensor units, by transmitting a third message that comprises the first sensor measurement in encrypted form, an address portion, an integrity portion comprising a checksum, and an authentication portion for use in verifying authenticity of the first message;
ignoring, by the second wireless repeater unit, in accordance with the first list, the first sensor measurement made by the first wireless sensor unit;
relaying, by the second wireless repeater unit, based on the selected routing paths, a second sensor measurement made by a second wireless sensor unit of the one or more wireless sensor units, by transmitting a fourth message that comprises the second sensor measurement in encrypted form, an address portion, an integrity portion comprising a checksum, and an authentication portion for use in verifying authenticity of the second message; and
ignoring, by the first wireless repeater unit, in accordance with the second list, the second sensor measurement made by the second wireless sensor unit.

10. The method of routing communication traffic in a wireless sensor system of claim 9 , wherein the first and second wireless repeater units each have a respective list of sensors and the method further comprises, for each of the first and second wireless repeater units:
causing the wireless repeater unit to forward a fifth message addressed to a sensor on the wireless repeater unit's list of sensors

Assignees

• Google Inc

Inventors

• Kates Lawrence

Classifications

• G08B25/10 Primary

  using wireless transmission systems {(G08B25/009 takes precedence)} · CPC title

• G08B17/10

  Actuation by presence of smoke or gases {, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means} · CPC title

• G08B13/04

  by breaking of glass · CPC title

• H04Q9/02

  Automatically-operated arrangements · CPC title

• G08B25/007

  Details of data content structure of message packets; data protocols · CPC title