Wireless communications providing interoperability between devices capable of communicating at different data rates

• US 8,855,102 B2
• Filed: 12/20/2010
• Issued: 10/07/2014
• 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: Borleske, Andrew J., Brian, Brent, Mason, Robert T. Jr.
• Primary Examiner(s): Moore, Ian N
• Assistant Examiner(s): Smith, Eric P
• Application Number:
  US12/972,826
• Publication Number:
  US 20110188516A1
• Time in Patent Office: 1,387 Days
• Field of Search: None
• US Class Current: 370/350
• 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) value that identifies an end of the synchronization header and a start of packet data;

identifying a data rate of the packet data as one of the first data rate or the second data rate as a function of the start-of-frame delimiter value;

collecting a plurality of samples of the signal;

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

performing an adjustment to a bit timing of the first device based on the determined number of bit errors;

after adjusting the bit timing of the first device, collecting a plurality of additional samples of the signal; and

performing an additional adjustment to the bit timing of the first device, wherein the additional adjustment is limited to a configurable allowed amount.

2. The method of claim 1, further comprising:

comparing the start-of-frame delimiter 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, wherein the synchronization header further comprises an end of preamble waveform.

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

5. A wireless 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;

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) 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, and

wherein the particular bidirectional node is configured to collect a plurality of samples of the data communication, determine a number of bit errors in the plurality of samples relative to an ideal waveform, perform an adjustment to a bit timing of the particular bidirectional node based on the determined number of bit errors, collect a plurality of additional samples of the data communication after adjusting the bit timing of the particular bidirectional node, and perform an additional adjustment to the bit timing of the particular bidirectional node, wherein the additional adjustment is limited to a configurable allowed amount.

6. The wireless network of claim 5, wherein the particular bidirectional node is configured to:

compare the start-of-frame delimiter 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.

7. The wireless network of claim 5, wherein the synchronization header further comprises an end of preamble waveform.

8. The wireless network of claim 5, 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.

9. The wireless network of claim 5, 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 reply preamble waveform having a reply preamble waveform duration equal to the duration of the preamble waveform of the data communication initiated by the central node.

10. The wireless network of claim 5, 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 bidirectional node at the maximum data rate at which the particular bidirectional node is capable of communicating.

11. A processor-readable storage memory storing processor-executable instructions that, when executed by a processor, cause the processor to operate 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 by:

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

identifying a data rate of the packet data as one of the first data rate or the second data rate as a function of the start-of-frame delimiter value;

collecting a plurality of samples of the signal;

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

performing an adjustment to a bit timing of the first device based on the determined number of bit errors;

after adjusting the bit timing of the first device, collecting a plurality of additional samples of the signal; and

performing an additional adjustment to the bit timing of the first device, wherein the additional adjustment is limited to a configurable allowed amount.

12. The processor-readable storage memory of claim 11, storing further processor-executable instructions that, when executed by the 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.

13. The processor-readable storage memory of claim 11, wherein the synchronization header further comprises an end of preamble waveform.

14. The processor-readable storage memory of claim 11, wherein the preamble waveform has a duration, and wherein the processor-readable storage memory stores further processor-executable instructions that, when executed by the processor, cause the processor to transmit, from the first device, a reply having a reply preamble waveform having a reply preamble waveform duration equal to the duration of the preamble waveform of the received signal.