Method and system for providing an energy efficient exchange of information in wireless networks

• US 7,536,194 B2
• Filed: 09/30/2005
• Issued: 05/19/2009
• Est. Priority Date: 09/30/2005
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Srinivasan, Bhaskar, Venkatraman, Lakshmi, Manjeshwar, Arati
• Primary Examiner(s): Eisen; Alexander
• Assistant Examiner(s): LEE, JUSTIN YE
• Application Number:
  US11/239,837
• Publication Number:
  US 20070077951A1
• Time in Patent Office: 1,327 Days
• Field of Search: 370/503, 370/507, 370/509, 370/512, 370/514, 370/520, 370/525, 340/825.2, 340/525.21, 375/356
• US Class Current: 455/515
• CPC Class Codes: G04G 7/02 by radio

Abstract

A method and system to synchronize a first device and a second device includes generating a first tone by the first device, the first tone one of including an identity of the second device and generated at a predefined time, receiving the first tone by the second device, setting a clock of the second device based on the received first time, and sending an acknowledgment by the second device to the first device.

Claims

1. A method of synchronizing a first device and a second device, comprising:

generating a first tone by the first device, the first tone one of (a) including an identity of the second device and (b) generated at a predefined time;

receiving the first tone by the second device;

setting a clock of the second device based on the received first tone;

sending an acknowledgment by the second device to the first device;

(i) waiting for a predefined period of time by the second device for an indication of acknowledged receipt of the acknowledgement;

(ii) waking up in a subsequent supervision time slot to receive the indication of acknowledged receipt of the acknowledgement if the indication is not received within the predefined period of time;

repeating steps (i) and (ii) for a predefined number of times; and

transmitting a poll by the second device to the first device if the indication of acknowledged receipt is not received.

2. The method of claim 1, further comprising:

generating a second tone by the first device for the indication of acknowledged receipt of the acknowledgement;

receiving the second tone by the second device; and

entering into sleep mode by the second device.

3. The method of claim 2, wherein the first tone and the second tone are distinguishable via a single bit.

4. The method of claim 2, wherein the second device enters the sleep mode in response to receipt, by the second device, of the second tone.

5. The method of claim 1, wherein the first and second devices are wireless communication devices.

6. The method of claim 5, wherein the tone is used to ensure a connectivity status between the communication devices.

7. The method of claim 5, wherein the tone is used to supervise the second drive.

8. The method of claim 5, wherein the tone includes a short pulse.

9. The method of claim 1, wherein the tone includes the identity of the second device.

10. The method of claim 1, wherein the second device is an energy-constrained device.

11. The method of claim 1, wherein the tone is transmitted in a predefined time slot allocated for supervision.

12. The method of claim 11, further comprising:

waking up, by the second device, in the predefined time slot to receive the tone.

13. The method of claim 1, wherein the predefined time is known to the second device and wherein the clock is set based on the predefined time known to the second device.

14. The method of claim 1, further comprising:

transmitting, by the first device, another tone in a default frequency if a predefined supervision interval expires and the acknowledgement and the poll is not received.

15. The method of claim 1, further comprising:

entering into sleep mode by the second device in response to receiving, by the second device, the indication of acknowledged receipt of the acknowledgement.