Processing gain for wireless communication, such as in automatic data collection systems for public utility data collection

• US 20050078631A1
• Filed: 09/27/2004
• Published: 04/14/2005
• Est. Priority Date: 09/26/2003
• Status: Active Grant

• Current Assignee: Itron, Inc.
• Original Assignee: Itron, Inc.
• Inventors: Cornwall, Mark K.
• Granted Patent: US 7,346,030 B2
• Time in Patent Office: Days
• US Class Current: 370/330
• CPC Class Codes: H04Q 2209/40 using a wireless architecture
• CPC Class Codes: H04Q 2209/50 using a mobile data collecting device, e.g. walk by or drive by
• CPC Class Codes: H04Q 2209/60 for transmitting utility meters data, i.e. transmission of data from the reader of the utility meter
• 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

Abstract

Several embodiments are described that increase processing gain. Under one embodiment, a wireless receiver quickly and accurately determines a particular frequency hopping table employed by a transmitter. Under another embodiment, the wireless receiver accumulates packets, such as packets containing utility meter data, and employs a mathematical process on the packets to generate an improved, decodable packet. Other embodiments are described in detail.

Claims

1. A wireless communication system for processing utility consumption data, the system comprising:

multiple transmitting nodes, each configured to wirelessly transmit a substantially similar message multiple times and according to one of multiple different frequency hopping tables, wherein each of the transmitting nodes receives utility consumption data from an associated utility meter; and

a mobile receiving node configured to wirelessly receive at least one of the transmitted messages on one frequency from one of the transmitting nodes, and to perform a first routine at least twice to determine which one of the multiple different frequency hopping tables the one transmitting node is employing, wherein the routine includes;

guessing a next frequency on which the one transmitting node will next transmit a message, and

listening at the next frequency for the next transmission of a message, and

wherein the mobile receiving node wirelessly receives and stores at least two of the transmitted messages after determining the one frequency hopping table employed by the one transmitting node, and wherein the receiving node performs a second routine to decode the at least two received and stored messages, wherein the second routine comprises;

applying a mathematical operation to the two received and stored messages to produce an improved message, and

decoding at least a portion of the improved message.

2. The method of claim 1 wherein the mobile receiving node performs a third routine, before the second routine, wherein the third routine comprises:

determining a time gap between pairs of received messages to determine at least first and second differing time gaps;

comparing the first and second differing time gaps to multiple time dithering tables to identify one of the tables having the first and second differing time gaps; and

identifying the one transmitting node, at least in part, on the identified table.

3. In an automatic utility meter reading system, a wireless communication method between at least one transmitting node associated with a utility meter, and a receiving node, the method comprising:

at the transmitting node associated with the utility meter, wirelessly transmitting a substantially similar message multiple times, wherein at least some of the messages include data related to consumption of a utility; and

at the receiving node;

wirelessly receiving and storing at least two of the transmitted messages,

applying a mathematical operation to the received and stored messages to produce an improved message, and

decoding at least a portion of the improved message to retrieve at least some of the data related to consumption of the utility.

4. The method of claim 3 wherein the transmitting node is configured to communicate with a utility meter, wherein the mathematical operation is summation or integration, wherein the mathematical operation is performed only if a received message cannot be accurately decoded, and wherein only messages substantially separated by a predetermined time period are summed or integrated.

5. The method of claim 3 wherein the mathematical operation is summation or integration, and wherein only messages substantially separated by a predetermined time period are summed or integrated.

6. The method of claim 3 wherein the mathematical operation is summation or integration, and wherein the mathematical operation is performed only if a received message cannot be accurately decoded.

7. The method of claim 3 wherein the mathematical operation is averaging, and wherein the receiving node filters received messages before the averaging.

8. The method of claim 3 wherein the receiving node determines an algorithmically determined time interval between messages before performing the mathematical operation.

9. The method of claim 3 wherein the receiving node stores, for each received message, a time stamp and at least one of the following:

a received signal strength, a hopping pattern, or a message preamble.

10. The method of claim 3 wherein the receiving node stores, for each received message, a message preamble, wherein the message preamble is a hexadecimal number or a pseudo-random number that relates to a utility meter system having a transmitter.

11. The method of claim 3, further comprising determining whether a trigger channel has been crossed before wirelessly receiving and storing.

12. The method of claim 3 wherein multiple transmitting nodes exist, wherein after a power outage, the receiving node stores received messages from at least some of the multiple transmitting nodes, and wherein the receiving node decodes stored messages from geographically closer transmitting nodes before decoding stored messages from geographically farther transmitting nodes.

13. The method of claim 3 wherein the receiving node is located on a vehicle, and wherein the transmitting node is coupled to a utility meter.

14. The method of claim 3 wherein the receiving node includes a correlator to detect a predetermined preamble in received messages.

15. The method of claim 3 wherein the receiving node stores, for each received message, an analog waveform of the received message.

16. A wireless communication method between a transmitting node and a receiving node, the method comprising:

at the transmitting node, wirelessly transmitting messages according to one of multiple different frequency hopping tables, wherein the transmitting node is associated with a utility meter for gathering data associated with consumption of a utility, and wherein at least some of the transmitted messages contain data associated with consumption of a utility; and

at the receiving node, wirelessly receiving at least one of the transmitted messages on one frequency and performing a routine at least twice to determine which of the multiple different frequency hopping tables the transmitting node is employing, wherein the routine includes;

guessing a next frequency on which the transmitting node will next transmit a message, and

listening at the next frequency for the next transmission of a message to determine which of the multiple different frequency hopping tables the transmitting node is employing.

17. The method of claim 16, further comprising listening on a hailing channel before guessing the next frequency.

18. The method of claim 16 wherein the receiving node includes a multi-channel receiver, and wherein the method further comprises wirelessly receiving signals on multiple frequencies substantially simultaneously.

19. The method of claim 16, further comprising:

determining a time gap between pairs of received messages to determine at least first and second differing time gaps;

comparing the first and second differing time gaps to multiple time dithering tables to identify one of the tables having the first and second differing time gaps; and

identifying the transmitting node, at least in part, on the identified table.

20. The method of claim 16, further comprising:

determining first and second time differences between two different pairs of received messages; and

identifying the transmitting node, at least in part, on the determined first and second time differences.

21. A computer-readable medium whose contents cause at least one mobile wireless receiver to perform a method to determine an identity of one of multiple transmitting nodes, and wherein each of the multiple transmitting nodes wirelessly transmit messages according to one of multiple different frequency hopping tables, the method comprising:

wirelessly receiving at least one of the transmitted messages on one frequency and performing a routine at least twice to determine which of the multiple different frequency hopping tables the one transmitting node is employing, wherein each of the multiple transmitting nodes are associated with a respective one utility meter that gathers utility consumption data, and wherein at least some of the transmitted messages contain utility consumption data;

guessing a next frequency on which the one transmitting node will next transmit a message; and

listening at the next frequency for the next transmission of a message to determine the identity of the one transmitting nodes from an identified one of multiple different frequency hopping tables the one transmitting node is employing.

22. The computer-readable medium of claim 21 wherein the computer-readable medium is a memory of a mobile wireless utility data collection device.

23. The computer-readable medium of claim 21 wherein the computer-readable medium is a logical node in a computer network receiving the contents.

24. The computer-readable medium of claim 21 wherein the computer-readable medium is a computer-readable disk.

25. The computer-readable medium of claim 21 wherein the computer-readable medium is a data transmission medium carrying a generated data signal containing the contents.

26. The computer-readable medium of claim 21 wherein the computer-readable medium is a memory of a computer system.

27. The computer-readable medium of claim 21, further comprising:

determining first and second time differences between two different pairs of received messages; and

identifying the transmitting node, at least in part, on the determined first and second time differences.

28. In a utility data collection system having multiple transmitting endpoints, wherein each transmitting endpoint is associated with a respective utility meter and is configured to receive utility consumption data from the respective one utility meter, and wherein each transmitting endpoint is further configured to wirelessly transmit substantially similar packets of utility consumption data at multiple times, an apparatus for decoding the utility consumption data packets, comprising:

means for wirelessly receiving data, wherein the means for wirelessly receiving data is mobile, and includes;

means for storing at least two of the transmitted utility consumption data packets from one of the transmitting endpoints,

means, coupled to the means for storing, for applying a mathematical operation to the received and stored utility consumption data packets to produce an improved utility consumption data packet, and

means, coupled to the means for applying a mathematical operation, for decoding at least a portion of the improved utility consumption data packet.