TRAFFIC COLLISION AVOIDANCE IN WIRELESS COMMUNICATION SYSTEMS

• US 20140333423A1
• Filed: 07/23/2014
• Published: 11/13/2014
• Est. Priority Date: 05/27/2004
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Nest Labs Incorporated (Alphabet Inc.)
• Inventors: Kates, Lawrence
• Granted Patent: US 9,286,788 B2
• Time in Patent Office: Days
• US Class Current: 340/309.16
• CPC Class Codes: G06F 1/3209 Monitoring remote activity, e.g. over telephone lines or network connections
• CPC Class Codes: G08B 1/08 using electric transmission ; transformation of alarm signals to electrical signals from a different medium, e.g. transmission of an electric alarm signal upon detection of an audible alarm signal
• CPC Class Codes: G08B 13/04 by breaking of glass
• CPC Class Codes: G08B 17/00 Fire alarms; Alarms responsive to explosion
• CPC Class Codes: G08B 17/10 Actuation by presence of smoke or gases , e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means
• CPC Class Codes: G08B 21/14 Toxic gas alarms G08B21/16 takes precedence
• CPC Class Codes: G08B 21/182 Level alarms, e.g. alarms responsive to variables exceeding a threshold
• CPC Class Codes: G08B 25/001 Alarm cancelling procedures or alarm forwarding decisions, e.g. based on absence of alarm confirmation
• CPC Class Codes: G08B 25/007 Details of data content structure of message packets; data protocols
• CPC Class Codes: G08B 25/009 Signalling of the alarm condition to a substation whose identity is signalled to a central station, e.g. relaying alarm signals in order to extend communication range
• CPC Class Codes: G08B 25/10 using wireless transmission systems G08B25/009 takes precedence
• CPC Class Codes: H04Q 9/00 Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom
• CPC Class Codes: H04Q 9/02 Automatically-operated arrangements
• CPC Class Codes: H04W 52/0225 using monitoring of external events, e.g. the presence of a signal
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: Y02B 70/30 Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
• CPC Class Codes: Y02D 30/70 in wireless communication networks

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.

Claims

1. A method of avoiding transmission collisions within a wireless sensor system, comprising:

programming a delay value into each of one or more wireless repeater units;

waiting for said delay value by each of said one or more wireless repeater units before forwarding communications from a base unit to one or more wireless sensor units; and

waiting for said delay value by each of said one or more wireless repeater units before forwarding communications from said one or more wireless sensor units to said base unit.

2. The method of avoiding transmission collisions within a wireless sensor system of claim 1, wherein the delay value is programmed into the one or more wireless repeater units by the base unit.

3. The method of avoiding transmission collisions within a wireless sensor system of claim 1, wherein the delay value for the one or more wireless repeater units is randomly chosen by each of the one or more wireless repeater units.

4. The method of avoiding transmission collisions within a wireless sensor system of claim 1, wherein the one or more wireless repeater units each randomly chooses a delay value for each forwarded packet of said communications.

5. The method of avoiding transmission collisions within a wireless sensor system of claim 1, wherein each of said one or more wireless repeater units is configured to begin transmission on different frequency channels, such that if two repeaters attempt to begin transmission at the same time, the transmissions will begin on different channels.

6. The method of avoiding transmission collisions within a wireless sensor system of claim 1, further comprising:

forwarding communications from the base unit to the one or more wireless sensor units on a first frequency channel; and

forwarding communications from said one or more wireless sensor units to said base unit on a different frequency channel, such that if two repeaters attempt to begin transmission at the same time, the transmissions will begin on different channels.

7. The method of avoiding transmission collisions within a wireless sensor system of claim 1, wherein each of said one or more wireless repeater units is configured to listen to a frequency channel, wherein the waiting for said delay value by each of said one or more wireless repeater units is in response to a determination that there is activity on the frequency channel.

8. The method of avoiding transmission collisions within a wireless sensor system of claim 7, wherein the delay value for the one or more wireless repeater units is randomly chosen by each of the one or more wireless repeater units and the delay value for a first one of the one or more wireless repeater units is different than the delay value for a second one of the one or more wireless repeater units.

9. A wireless repeater unit, comprising:

a wireless transceiver capable of wirelessly transmitting and receiving information to and from electronic devices located remotely from the wireless repeater unit;

a power source for powering operation of the wireless repeater unit; and

a controller operatively coupled to the wireless transceiver and the power source and configured to;

program a delay value into the wireless repeater unit;

cause the wireless repeater unit to wait for said delay value before forwarding communications, via the wireless transceiver, from a base unit to one or more wireless sensor units; and

cause the wireless repeater unit to wait for said delay value before forwarding communications, via the wireless transceiver, from said one or more wireless sensor units to said base unit.

10. The wireless repeater unit of claim 9, further comprising memory wherein the controller is configured to program a delay value by storing a randomly-chosen delay value into the memory of the wireless repeater unit.

11. The wireless repeater unit of claim 9, wherein the controller is configured to program the delay value by wirelessly receiving the delay value via the wireless transceiver.

12. The wireless repeater unit of claim 9, further comprising a list of sensor units, wherein the controller is configured to cause the wireless repeater unit to forward communications from the base unit to one or more wireless sensor units only when the one or more wireless sensor units are on the list of sensor units.

13. The wireless repeater unit of claim 9, further comprising a unique identifier associated with the wireless repeater unit for uniquely identifying the wireless repeater unit within a network, wherein the controller is further configured to:

receive a communication from the base unit;

determine whether the communication includes the unique identifier;

when it is determined that the communication includes the unique identifier, forward the communication to the one or more wireless sensor units after waiting for the delay value; and

when it is determined that the communication does not include the unique identifier, ignore the communication.

14. The wireless repeater unit of claim 13, wherein the communication includes a command for instructing at least one of the one or more wireless sensor units to perform an operation.

15. The wireless repeater unit of claim 14, wherein the command is selected from the group consisting of:

wake up, report status, and change wake-up interval.

16. A method of avoiding transmission collisions within a wireless sensor system, comprising:

determining at least one delay value for a wireless repeater unit;

waiting for a first delay value of the at least one delay value before forwarding communications from a base unit to one or more wireless sensor units via the wireless repeater unit; and

waiting for a second delay value of the at least one delay value before forwarding communications from said one or more wireless sensor units to said base unit via the wireless repeater unit.

17. The method of avoiding transmission collisions within a wireless sensor system of claim 16, wherein each of the at least one delay value is a random value, the first delay value is a random value, the second delay value is a random value, and the first delay value is different than the second delay value.

18. The method of avoiding transmission collisions within a wireless sensor system of claim 16, wherein the communications forwarded from the base unit to the one or more wireless sensor units are sent by the wireless repeater unit until an acknowledgement message is received by the wireless repeater unit from the one or more wireless sensor units.

19. The method of avoiding transmission collisions within a wireless sensor system of claim 16, further comprising:

receiving, at the wireless repeater unit and from the one or more wireless sensor units for forwarding to the base unit, communications at programmed intervals; and

receiving, at the wireless repeater unit and from the one or more wireless sensor units for forwarding to the base unit, communications at intermittent periods of time that are representative of a dangerous condition, the dangerous condition indicating that an ambient environmental condition exceeds at least one threshold of at least one sensor included in the one or more wireless sensor units.

20. The method of avoiding transmission collisions within a wireless sensor system of claim 16, wherein the communications received at intermittent periods of time that are representative of a dangerous condition include a message indicative of an ambient environmental condition exceeding a threshold of a sensor included in one of the one or more wireless sensor units, a unique identifier that uniquely identifies the one of the one or more wireless sensor units within the wireless sensor system, and an integrity portion for verifying the integrity of the message, and the method further comprises forwarding the message and the unique identifier to the base unit after waiting for the second delay value.