Transmitting radio signals using simultaneous retransmission

• US 9,307,509 B1
• Filed: 05/16/2013
• Issued: 04/05/2016
• Est. Priority Date: 05/16/2013
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Heninwolf, Paul, Marringa, Menno
• Primary Examiner(s): Shivers, Ashley
• Application Number:
  US13/895,462
• Time in Patent Office: 1,055 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H04L 45/16 Multipoint routing
• CPC Class Codes: H04L 47/806 Broadcast or multicast traffic
• CPC Class Codes: H04L 51/226 Delivery according to priorities
• CPC Class Codes: H04L 51/234 for tracking messages
• CPC Class Codes: H04W 56/002 Mutual synchronization
• CPC Class Codes: H04W 56/0045 compensating for timing error by altering transmission time
• CPC Class Codes: H04W 56/005 compensating for timing error by adjustment in the receiver

Abstract

Disclosed is a simulcast approach to broadcasting a message from each device, or node, of a network. A source device, such as a wall switch, may broadcast a message that may be received by a plurality of devices, such as light bulbs, in a network. Each of the plurality of devices may receive the message at substantially the same time. In response to the message, the receiving devices may determine if the message is to be retransmitted. If the message is to be retransmitted, it may generate a modified message. Each of the plurality of devices may transmit the modified message substantially simultaneously. To maintain timing to the source device between the devices in the network, the message may be configured to facilitate synchronization of the clocks to a timing signal in the message.

Claims

1. A method comprising:

receiving by a first device a first message from a source device, the message including data identifying a destination device from among a plurality of devices in a wireless network;

determining that the first device is an intermediary device;

determining a timing of the reception of the first message;

determining a time period for transmitting a modified message, after the determined timing of the reception of the first message, by summing a predefined duration of the first message with a predefined synchronization time period;

synchronizing a clock of the first device to a predefined timing signal included with the first message; and

transmitting, by the first device, a first modified message based upon the synchronized clock and the identified time period.

2. The method of claim 1, wherein the predefined timing signal is appended to the first message.

3. The method of claim 1, further comprising:

modifying the first message by changing a predetermined number of message retransmissions included in the first message.

4. The method of claim 3, wherein the changing comprises decrementing the number of message retransmissions.

5. The method of claim 1, further comprising:

receiving the first message by a second device simultaneously with the first device;

determining that the second device is an intermediary device;

identifying a time period for transmitting a modified message;

synchronizing a clock of the second device to a predefined timing signal included with the first message; and

transmitting, by the second device, a second device modified message based upon the synchronized clock and the identified time period.

6. The method of claim 5, wherein the second device modified message is transmitted simultaneously with the modified message sent by the first device.

7. The method of claim 6, further comprising:

synchronizing a clock in each respective device of the plurality of devices to the predefined timing signal in the message.

8. The method of claim 1, further comprising:

in response to a determination that the first device is an intended recipient of the first message, transmitting regardless of the timing signal by the first device an acknowledgement signal indicating that the signal was received by the first device.

9. The method of claim 1, further comprising:

in response to a determination that the message is to be retransmitted, transmitting the modified message based on the timing signal.

10. The method of claim 1, wherein the first modified message includes the data identifying the destination device as the intended recipient of the device.

11. The method of claim 1, wherein the message includes an indicator that signals a timer needs to start so the identified time period for transmitting the modified message can begin.

12. A method comprising:

receiving, by a first device of a plurality of devices in a wireless network, a first message from a source device, the message including a retransmission value and a destination device identifier that identifies a destination device from among the plurality of devices;

receiving a predefined timing signal from the source device, wherein the predefined timing signal is appended to the first message, the timing signal comprising a series of bits that change in value at a frequency similar to the frequency of a native clock in the receiving device;

based upon a result of a comparison of the destination device identifier with a first device identifier, performing a sequence of actions selected from the group consisting of;

(i) determining that the first device is not the sole destination device;

decrementing the retransmission value; and

transmitting, by the first device, a first modified message based upon the first message and the predefined timing signal, the first modified message comprising the decremented retransmission value; and

(ii) determining that the first device is a destination device; and

transmitting an acknowledgement signal indicating that the first message was received by the destination device, the acknowledgement signal being transmitted after a period of time corresponding to a remaining expected retransmissions.

13. The method of claim 12, further comprising:

comparing a first device identifier to the destination device identifier.

14. The method of claim 12, wherein the first modified message includes the first device identifier.

15. The method of claim 12, further comprising:

synchronizing a clock to the predefined timing signal.

16. The method of claim 12, further comprising:

receiving at a second device the first message and the predefined timing signal;

comparing the device identifier to a second device identifier of the second device;

in response to a determination that the second device is an intermediary device, decrementing the retransmission value in the first message; and

transmitting, by the second device, a second modified message based upon the first message and the predefined timing signal, the second modified message including the decremented retransmission value.

17. The method of claim 12, further comprising:

in response to a determination that the second device is a destination device, transmitting an acknowledgement signal indicating that the first message was received by the destination device, the acknowledgement signal being broadcast at a time selected without regard to the timing signal.

18. A method, comprising:

generating a data frame based on input signals received at a processor, wherein the data frame includes data identifying a destination device and a retransmission value;

appending a timing signal to the end of the data frame to form a message including the data frame and the timing signal, the timing signal comprising a series of bits that change in value at a frequency similar to the frequency of a native clock in the receiving device;

broadcasting the message to a plurality of devices;

receiving the message by a plurality of intermediary devices of the plurality of devices that are not the destination device;

processing the message at all of the intermediary devices that receive the message to determine if the message is to be retransmitted based on the retransmission value;

substantially synchronizing a native clock of all the intermediary devices that received the message to the timing signal appended to the message;

generating a modified message at the intermediary devices that received the message by changing the retransmission value in the message; and

transmitting the modified message substantially simultaneously by each of the respective intermediary devices that received the message according to the intermediary device'"'"'s synchronized clock.

19. The method of claim 18, further comprising:

in response to a determination that the receiving device is a destination device, modifying the message to indicate the number of times the message was retransmitted.

20. The method claim 18, further comprising:

processing the message at all of the intermediary devices that receive the message to determine if the intermediary device is a destination device.

21. A method comprising:

receiving by a first device a first message from a source device, the message including data identifying a destination device from among a plurality of devices in a wireless network;

determining that the first device is an intermediary device;

determining a time at which a last data frame of the first message ends;

determining a time period for transmitting a modified message, the time period being equal to a predefined synchronization time period;

synchronizing a clock of the first device to a predefined timing signal included with the first message; and

transmitting, by the first device, a first modified message based upon the synchronized clock and the identified time period.

22. The method of claim 21, wherein the predefined timing signal is appended to the first message.

23. The method of claim 21, further comprising:

modifying the first message by changing a predetermined number of message retransmissions included in the first message.

24. The method of claim 23, wherein the changing comprises decrementing the number of message retransmissions.

25. The method of claim 21, further comprising:

receiving the first message by a second device simultaneously with the first device;

determining that the second device is an intermediary device;

identifying a time period for transmitting a modified message;

synchronizing a clock of the second device to a predefined timing signal included with the first message; and

transmitting, by the second device, a second device modified message based upon the synchronized clock and the identified time period.

26. The method of claim 25, wherein the second device modified message is transmitted simultaneously with the modified message sent by the first device.

27. The method of claim 26, further comprising:

synchronizing a clock in each respective device of the plurality of devices to the predefined timing signal in the message.

28. The method of claim 21, further comprising:

in response to a determination that the first device is an intended recipient of the first message, transmitting regardless of the timing signal by the first device an acknowledgement signal indicating that the signal was received by the first device.

29. The method of claim 21, further comprising:

in response to a determination that the message is to be retransmitted, transmitting the modified message based on the timing signal.

30. The method of claim 21, wherein the first modified message includes the data identifying the destination device as the intended recipient of the device.

31. The method of claim 21, wherein the message includes an indicator that signals a timer needs to start so the identified time period for transmitting the modified message can begin.