WIRELESS COMMUNICATIONS PROVIDING INTEROPERABILITY BETWEEN DEVICES CAPABLE OF COMMUNICATING AT DIFFERENT DATA RATES

• US 20110188516A1
• Filed: 12/20/2010
• Published: 08/04/2011
• Est. Priority Date: 01/29/2010
• Status: Active Grant

• Current Assignee: Elster Solutions LLC (Honeywell International Inc.)
• Original Assignee: Elster Solutions LLC (Honeywell International Inc.)
• Inventors: Brian, Brent, Borleske, Andrew J., Mason, Robert T. JR.
• Granted Patent: US 8,855,102 B2
• Time in Patent Office: Days
• US Class Current: 370/474
• CPC Class Codes: H04J 3/24 in which the allocation is indicated by an address the different channels being transmitted sequentiallyH04J3/17 takes precedence; in computers G06F12/00, G06F13/00 code multiplex systems H04J13/00; selecting techniques H04Q; relay systems H04B7/14
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate
• CPC Class Codes: H04W 28/22 Negotiating communication rate
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

A method, wireless mesh network and processor-readable storage medium for providing interoperability between devices that are capable of communicating at different data rates are disclosed herein. A start-of-frame delimiter token value in a synchronization header is used to indicate a data rate at which a device is capable of communicating. In certain embodiments, samples are collected around a bit transition and are used to adjust a bit timing of a receiving device to match a bit timing of a transmitting device using a coarse adjustment process and, in some embodiments, a fine adjustment process. In this way, compatibility can be maintained between new devices that can communicate at a relatively fast data rate and legacy devices that communicate at a lower data rate.

Claims

1. A method of operating a wireless network comprising a first device configured to communicate data at a first data rate and a second device configured to communicate data at a second data rate different from the first data rate, the method comprising:

receiving, in the first device, a signal comprising a synchronization header comprising a preamble waveform and a start-of-frame delimiter (SFD) token value that identifies an end of the synchronization header and a start of packet data; and

identifying a data rate of the packet data as one of the first data rate and the second data rate as a function of the start-of-frame delimiter token value.

2. The method of claim 1, further comprising:

comparing the start-of-frame delimiter token value to a plurality of entries in a table;

receiving a result from the table; and

identifying the data rate of the packet data based on the result received from the table.

3. The method of claim 1, further comprising:

collecting a plurality of samples of the signal;

determining a number of bit errors in the plurality of samples relative to an ideal waveform; and

adjusting a bit timing of the first device based on the determined number of bit errors.

4. The method of claim 3, further comprising, after adjusting the bit timing of the first device:

collecting a plurality of additional samples of the signal; and

adjusting the bit timing of the first device by a predetermined time period.

5. The method of claim 1, wherein the synchronization header further comprises an end of preamble waveform.

6. The method of claim 1, wherein the preamble waveform has a duration, and further comprising transmitting, from the first device, a reply having a preamble waveform having a duration equal to the duration of the preamble waveform of the received signal.

7. A wireless mesh network comprising:

a central node comprising a transceiver configured to transmit and receive data communications using selected frequency channels of a plurality of frequency channels; and

a plurality of bidirectional nodes in bidirectional wireless communication with the central node, each bidirectional node having a respective wireless communication path to the central node that is either a direct path or an indirect path through one or more intermediate bidirectional nodes serving as repeater nodes;

wherein the central node initiates a data communication from the central node to a particular bidirectional node of the plurality of bidirectional nodes, the data communication comprising a synchronization header comprising a preamble waveform and a start-of-frame delimiter (SFD) token value that identifies an end of the synchronization header and a start of packet data and that identifies a data rate selected from a plurality of data rates.

8. The wireless mesh network of claim 7, wherein the particular bidirectional node is configured to:

compare the start-of-frame delimiter token value to a plurality of entries in a table;

receive a result from the table; and

identify the data rate based on the result received from the table.

9. The wireless mesh network of claim 7, wherein the particular bidirectional node is configured to:

collect a plurality of samples of the signal;

determine a number of bit errors in the plurality of samples relative to an ideal waveform; and

adjust a bit timing of the first device based on the determined number of bit errors.

10. The wireless mesh network of claim 9, wherein the particular directional node is further configured to, after adjusting the bit timing of the first device:

collect a plurality of additional samples of the signal; and

adjust the bit timing of the first device by a predetermined time period.

11. The wireless mesh network of claim 7, wherein the synchronization header further comprises an end of preamble waveform.

12. The wireless mesh network of claim 7, wherein the plurality of bidirectional nodes comprises:

at least one first node communicating data at a first data rate of the plurality of data rates; and

at least one second node communicating data at a second data rate of the plurality of data rates, the second data rate being higher than the first data rate.

13. The wireless mesh network of claim 7, wherein the preamble waveform of the data communication initiated by the central node has a duration, and wherein the particular bidirectional node is configured to transmit a reply having a preamble waveform having a duration equal to the duration of the preamble waveform of the data communication initiated by the central node.

14. The wireless mesh network of claim 7, wherein the central node is configured to:

determine a maximum data rate at which the particular bidirectional node is capable of communicating; and

communicate with the particular directional node at the maximum data rate at which the particular bidirectional node is capable of communicating.

15. A processor-readable storage medium storing processor-executable instructions that, when executed by a processor, cause the processor to operate a wireless mesh network comprising a first device configured to communicate data at a first data rate and a second device configured to communicate data at a second data rate different from the first data rate by:

receiving, in the first device, a signal comprising a synchronization header comprising a preamble waveform and a start-of-frame delimiter (SFD) token value that identifies an end of the synchronization header and a start of packet data; and

identifying a data rate of the packet data as one of the first data rate and the second data rate as a function of the start-of-frame delimiter token value.

16. The processor-readable storage medium of claim 15, storing further processor-executable instructions that, when executed by a processor, cause the processor to:

compare the start-of-frame delimiter token value to a plurality of entries in a table;

receive a result from the table; and

identify the data rate of the packet data based on the result received from the table.

17. The processor-readable storage medium of claim 15, storing further processor-executable instructions that, when executed by a processor, cause the processor to:

collect a plurality of samples of the signal;

determine a number of bit errors in the plurality of samples relative to an ideal waveform; and

adjust a bit timing of the first device based on the determined number of bit errors.

18. The processor-readable storage medium of claim 17, storing further processor-executable instructions that, when executed by a processor, cause the processor to, after adjusting the bit timing of the first device:

collect a plurality of additional samples of the signal; and

adjust the bit timing of the first device by a predetermined time period.

19. The processor-readable storage medium of claim 15, wherein the synchronization header further comprises an end of preamble waveform.

20. The processor-readable storage medium of claim 15, wherein the preamble waveform has a duration, and wherein the processor-readable storage medium stores further processor-executable instructions that, when executed by a processor, cause the processor to transmit, from the first device, a reply having a preamble waveform having a duration equal to the duration of the preamble waveform of the received signal.