Method of RF-based communication

• US 6,219,655 B1
• Filed: 09/02/1999
• Issued: 04/17/2001
• Est. Priority Date: 09/17/1997
• Status: Expired due to Fees

• Current Assignee: Cin Itron
• Original Assignee: Cin Itron
• Inventors: Myers, Gregory K., Schleich, Michael G.
• Primary Examiner(s): Trammell, James P.
• Assistant Examiner(s): Dixon, Thomas A.
• Application Number:
  US09/388,692
• Time in Patent Office: 593 Days
• Field of Search: 705/412, 705/413, 705/417, 705/418, 340/870.02, 340/870.03, 340/870.11, 340/870.07, 702/60, 702/61, 702/62, 702/64, 702/65, 324/114, 324/115, 324/116, 324/140.R, 324/142
• US Class Current: 705/412
• CPC Class Codes: G01D 4/006 Remote reading of utility meters to a non-fixed location, i.e. mobile location
• CPC Class Codes: G01R 21/133 by using digital technique
• CPC Class Codes: G01R 22/00 Arrangements for measuring time integral of electric power or current, e.g. electricity meters
• CPC Class Codes: G06Q 50/06 Energy or water supply
• CPC Class Codes: Y02B 90/20 Smart grids as enabling technology in buildings sector smart grids supporting the management or operation of end-user stationary applications in general, or like technologies with no associated climate change mitigation effect Y04S20/00
• CPC Class Codes: Y04S 20/30 Smart metering, e.g. specially adapted for remote reading

Abstract

An RF based communication system includes a transmitter for transmitting a signal. The transmitter is powered by an external power source and has a transmitter counter for generating a count. The count is linearly incremented over time. The transmitted signal includes the count at the time that the signal is transmitted. A receiver is communicatively coupled to the transmitter for receiving the signal transmitted by the transmitter. The receiver has a receiver counter, the receiver counter being asynchronous with respect to the transmitter counter.

Claims

1. A method for RF- based communication, comprising the steps of:

generating a first count that is linearly incremented over time, transmitting a signal by a transmitter, the signal including the count at the time that the signal is transmitted; and

receiving the transmitted signal by a receiver, and

generating a second count that is linearly incremented over time, the first count being asynchronous with respect to the second count.

2. The method of claim 1 including the step of the receiver calculating id the slope of the incrementally increasing first count.

3. The method of claim 2 including the step of the receiver calculating a predicted first count at a selected second count of the receiver.

4. The method of claim 3 including the step of passively time synchronizing the receiver and the transmitter by comparing the counts of the asynchronous second count and the first count.

5. The method of claim 3 including the step of calculating the difference between the predicted first count and the first count, the difference providing an indication of the occurrence of a power outage in the external power source and the duration of said power outage.

6. A method of metering communication for communicating data related to metered consumption of electrical energy to provide support for time-of-use and demand billing in the presence of at least one power outage event, the metering communication system being communicatively coupled to a sensor for sensing power consumption and for sensing power outage events, the sensor generating a sensor output signal having data related to at least the sensed power consumption and to power outage events, the metering communication system comprising the steps of:

communicating by means of an encoder device with the sensor for receiving the sensor output signal therefrom;

periodically generating an encoded RF signal for transmission by the encoder device;

including a power outage flag associated with the encoded RF signal,

setting the flag responsive to the sensor output signal and including data related to a power outage event;

decoding the encoded RF signal received from the encoder device by means of an interrogate/receiver device; and

transferring the decoded RF signal to a billing system by means of data transfer means.

7. The method of claim 6 including the steps of:

including a plurality of discrete components in he encoded RF signal, each of said components being related to electrical power consumption during a selected interval of time; and

associating a power outage flag with each discrete component.

8. The method of claim 7 including the step of powering the encoder device solely by the electrical power being metered.

9. The method of claim 8 including the step of incrementally increasing a count in the encoder device as a function of time.

10. The method of claim 9 including the step of incrementally increasing a count in the interrogate/receiver as a function of time, the interrogate/receiver count being asynchronous with respect to the encoder device count.

11. The method of claim 10 including the step of the interrogate/receiver device counting at a rate substantially equal to a real time counter.

12. The method of claim 11 including the step of flagging the decoded RF signal received from the encoder device prior to transmission to a billing system for each interval in which the consumption of electrical energy is estimated.

13. The method of claim 12 including the step of determining the difference between a predicted and an actual encoder count to predict a total power outage duration.

14. The method of claim 13 including the step of determining the IFS difference between a predicted and an actual encoder count to predict a total power outage duration of a plurality of power outages.

15. The method of claim 14 including the step of indicating a position in a buffer corresponding to a N-1 consumption value, the N-1 consumption value being a differentially encoded consumption value which occurred at a most recent consumption interval.

16. The method of claim 15 including the step of incrementing a pointer to identify a newly received N-1 consumption value.

17. The method of claim 16 including the steps of:

providing N-1 storage bins in the buffer;

storing a differential consumption value in each of said bins;

and

writing to each of said bins once every N-1 intervals.

18. The method of claim 17 including the steps of:

displacing the oldest consumption value in the buffer with the most recently received differential consumption value; and

incrementing the pointer by one to indicate the most recently received differential consumption value at the time of displacement.

19. The method of claim 18 including the step of writing the most recently arrived full consumption value and the buffer pointer to non-volatile memory at the time of a power outage.