Prepayment energy metering system with two-way smart card communications

• US 6,529,883 B1
• Filed: 08/20/1999
• Issued: 03/04/2003
• Est. Priority Date: 08/20/1999
• Status: Expired due to Fees

• Current Assignee: Salt River Project (Sims Ltd.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Zucarelli, Philip John, Keller, Theodore Woolley, Bickley, Robert Henry, Yee, David Moon
• Primary Examiner(s): Cosimano, Edward R.
• Application Number:
  US09/378,357
• Time in Patent Office: 1,292 Days
• Field of Search: 705/17, 705/63, 705/400, 705/412
• US Class Current: 705/63
• CPC Class Codes: G06Q 20/127 Shopping or accessing services according to a time-limitation
• CPC Class Codes: G06Q 20/20 Point-of-sale [POS] network systems
• CPC Class Codes: G06Q 20/28 Pre-payment schemes, e.g. "pay before"
• CPC Class Codes: G06Q 30/0283 Price estimation or determination
• CPC Class Codes: G06Q 50/06 Energy or water supply
• CPC Class Codes: G07F 15/00 Coin-freed apparatus with meter-controlled dispensing of liquid, gas or electricity
• CPC Class Codes: G07F 17/0014 for vending, access and use of specific services not covered anywhere else in G07F17/00 meter-controlled dispensing of liquid, gas or electricity G07F15/00

Abstract

A pre-payment energy metering system uses two-way smart card communications. Secure power line carrier communications are provided at the consumer locations communication between a customer terminal and the utility meter. Two-way secure communication of data is provided through the use of a smart card or memory card which conveys data from the utility service provider to the customer'"'"'s terminal and also conveys information from the customer'"'"'s terminal back to the utility. The pre-payment power system of the present invention allows consumers to pay for electricity prior to consumption through the use of the smart card which is loaded with funds at a fully automatic point-of-sale (POS) terminal or at the utility service providers staffed customer service center. Back office software interfaces between the POS terminals and customer service centers, and utility service providers customer information systems.

Claims

1. A prepayment energy metering communication method comprising the steps of:

reading from a communication card at a customer terminal a first data set, the first data set comprising a digital signature, a credit amount, a meter identifier, and a transaction identifier;

the customer terminal formatting the first data set into first packetized data and transferring the formatted first data set over a power line carrier to a utility meter;

the utility meter verifying said digital signature, the transaction identifier and the meter identifier;

storing said credit amount in the utility meter;

the utility meter formatting a second data set into second packetized data and transferring the formatted second packetized data set over the power line carrier to the customer terminal, the second data set comprising power measurement data;

a meter read time;

a remaining credit amount, and a second digital signature;

the customer terminal depacketizing the second packetized data set and transferring the second data set onto the communication card.

2. The method as claimed in claim 1 further comprising the step of the utility meter digitally signing at least a portion of the second data set to produce the second digital signature.

3. The method according to claim 1 wherein the power measurement data of the second data set further comprises a cumulative power consumption measurement, a meter read time, and a key status.

4. The method according to claim 1 wherein the communication card is comprised of semiconductor memory and a plurality of external electrical contacts, and wherein the reading step, the first data set is provided through at least one of the external electrical contacts,

and wherein the transferring the second data set onto the communication card step further comprises the step, the second data set is provided through said at least one of the external electrical contacts.

5. The method according to claim 1 further comprising the steps of reading the second data set from the communication card by an automated teller machine (ATM) and the ATM transferring second data set to the utility service provider, said ATM accepting a credit amount, communicating the credit amount with the utility service provider, receiving an updated first data set, and writing the updated first data set to the communication card.

6. The method according to claim 1 wherein the reading step includes the step of reading advertising data stored on the communication card, and wherein the method further includes the step of displaying said advertising data at the consumer terminal in response to the reading step.

7. The method as claimed in claim 1 wherein the verifying the transaction identifier step comprises the step of the utility meter comparing the transaction identifier with prior transaction identifiers and wherein the method further comprises the step of refraining from performing the storing the credit amount step when the transaction identifier compares with one of the prior transaction identifiers.

8. The method according to claim 1 further comprising the steps of the utility meter monitoring electricity consumption, and decrementing the remaining credit amount in accordance with rate tables stored in the meter and the electricity consumption.

9. The method according to claim 8 wherein the first data set further comprises new rate information, and wherein the storing step further comprises the step of storing the new rate tables in the utility meter, and wherein the method further comprises the step of the utility meter decrementing the remaining credit amount in accordance with the electricity consumption and the new rate tables.

10. The method as claimed in claim 1 wherein further comprising the steps of the utility meter monitoring electricity consumption rate, decrementing the remaining credit amount in accordance with rate information and the electricity consumption rate, and calculating an estimated time remaining based on prior electricity consumption, and

wherein the customer terminal further comprises a display, and

wherein the method further comprises the steps of the utility meter transmitting a third data set over the power line carrier to the customer terminal for displaying on the display, the third data set comprising the remaining credit amount, the electricity consumption rate and the estimated time remaining.

11. A method as claimed in claim 10 wherein the reading step includes the step of reading advertising data stored on the communication card, storing the advertising data in the utility meter and including the advertising data in said third data set for displaying at the consumer terminal.

12. The method as claimed in claim 10 wherein the transmitting the third data set step is performed at least on a regular basis, the regular basis being at least once every fifteen minutes, and wherein the method further comprises the step of transmitting the third data set in response to changes in the electricity consumption rate.

13. The method as claimed in claim 10 wherein the customer terminal further comprises an input/output device for receiving input from a user, and wherein the transmitting the third data set step is performed in response to input from the user.

14. The method as claimed in claim 1 wherein the communication card comprises memory means for storing digitally signed fixed data, the fixed data comprising an account number, a utility service provider identifier, a customer identifier, and the meter identifier, and wherein the method further comprises the step of a utility service provider digitally signing the fixed data with a private key of the utility service provider, and storing said digitally signed fixed data on the communication card.

15. The method as claimed in claim 14 wherein the utility service provider digitally signs the fixed data with a private key of the utility service provider, and wherein the method further comprises the step of the utility meter verifying the signature of the digitally signed fixed data with a public key of the utility service provider, the public key being stored in the utility meter.

16. The method as claimed in claim 15 wherein the first data set further comprises a certificate containing the public key of the utility service provider, and wherein the method further comprises the step of the meter verifying a digital signature of the certificate.

17. The method as claimed in claim 16 wherein the first data set further comprises an effective date associated with the public key of the utility service provider, and wherein the method further comprising the steps of storing the public key and the effective date in a memory of the utility meter, and wherein the verifying the signature of the digitally signed fixed data step is performed with said public key of the utility service provider after the effective date.

18. The method as claimed in claim 4 wherein the public key of the utility service provider is a first public key, and wherein the first data set further comprises a second public key, and first and second effective dates associated respectively with the first and second public keys of the utility service provider, and wherein the method further comprises the steps of storing the first and second public keys and associated effective dates in a memory of the utility meter, and wherein the verifying the signature of the digitally signed fixed data step is performed with the first public key prior to the second effective date and the second public key after the second effective date,

and wherein the first and second public keys are stored on the communication card in encrypted form.

19. A prepayment energy metering communication system comprising:

a customer terminal; and

a utility meter,

wherein the customer terminal comprises;

a communication card reader for reading from a communication card a first data set, the first data set comprising a digital signature, a credit amount, a meter identifier, and a transaction identifier;

a terminal controller; and

a terminal communications interface for formatting the first data set into first packetized data and transferring the formatted first data set over a power line carrier to the utility meter,

wherein the utility meter comprises;

a meter controller for verifying said digital signature, the transaction identifier and the meter identifier;

a memory for storing said credit amount; and

a meter communications interface for formatting a second data set into second packetized data and transferring the formatted second packetized data set over the power line carrier to the customer terminal, the second data set comprising power measurement data, a meter read time, a remaining credit amount, and a second digital signature,

wherein the terminal communications interface receives and depacketizes the second packetized data set and the terminal controller transfers the second data set onto the communication card.

20. The system as claimed in claim 19 wherein the utility meter further comprises clocking circuitry having means for providing a clock signal to the meter controller, the clocking circuitry using an A/C cycle rate when A/C power is available to provide the clock signal, the clocking circuitry using a crystal to provide the clock signal when AC power is not available.

21. A system as claimed in claim 20 wherein the communication card comprises electronically erasable programmable read only memory (EEPROM) and a plurality of contacts for communicating clock, ground, power and data signals.

22. A method of communicating data using a smart cart comprising the steps of:

storing a digital signature, a credit amount, a meter identifier, and a transaction identifier on the smart card;

transferring the digital signature, the credit amount, the meter identifier, and the transaction identifier to a utility meter using power line carrier communications;

storing utility consumption information on the smart card from the utility meter; and

transferring the utility consumption information from the smart card to a service provider.