Abstract:
One embodiment of the present invention sets forth a dual mode smart grid meter configured to operate within both an automatic meter reading (AMR) system and an advanced metering infrastructure (AMI) system. An AMR transmitter periodically transmits metrology data for interoperation with AMR reading operations. An AMI transceiver responds to AMI queries and commands for interoperation with AMI requirements. The disclosed dual mode smart grid meter beneficially enables utility operators to deploy or upgrade metering devices within an existing AMR network without disruption meter reading operations, while simultaneously preparing for an overall upgrade to reading operations based on AMI protocols.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims benefit of U.S. provisional patent application Ser. No. 61/697,086, filed Sep. 5, 2012 which is hereby incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    Embodiments of the present invention relate generally to digital smart grid systems and, more specifically, to a dual mode smart grid meter. 
         [0004]    2. Description of the Related Art 
         [0005]    Utility companies typically measure customer consumption of a commodity, such as electrical power or water, via a utility meter located at a customer premise. Historically, an individual would travel to the customer premise and visually inspect the utility meter to record an indicated consumption value. A subsequent generation of utility meter employs a radio communications technology known in the art as an automatic meter reading (AMR), which enables utility meters to be read via a wireless meter reader. An AMR utility meter periodically transmits a consumption value, and the wireless meter reader typically listens for asynchronously arriving transmissions from AMR utility meters. In a typical usage scenario, a wireless meter reader is disposed within a motor vehicle, which drives slowly along different customer streets to allow the wireless meter reader to accumulate customer consumption data. 
         [0006]    While utility meters employing AMR wireless transmission technology are an improvement in both meter reading accuracy and efficiency, a person still needs to travel near each utility meter to take a reading from the meter, potentially introducing human error in the process. Advanced metering infrastructure (AMI) technology enables utility meters to form bidirectional mesh networks, enabling a reader system to access a distant utility meter without needing to be in near physical proximity to the distant utility meter. A utility network built out to exclusively implement AMI meters enables tremendous efficiency and accuracy because each utility meter within the network may be read from a central location with little opportunity for human error. However, many utility operators have already invested significant resources to upgrade manually-read utility meters to meters with AMR technology. AMR systems and AMI systems may employ orthogonal communication protocols and architectures, and therefore do not conventionally interoperate. As a consequence, the conventional upgrade path from AMR meters to AMI meters requires a substantial system overhaul, which many utility operators are reluctant to implement. 
         [0007]    As the foregoing illustrates, what is needed in the art is a wireless utility meter system architecture that enables efficient use of both AMR to AMI technologies. 
       SUMMARY 
       [0008]    One embodiment of the present invention sets forth a computer-implemented method for transmitting metrology data, the method comprising determining whether an automatic meter reading (AMR) data packet should be transmitted or an advanced metering infrastructure (AMI) data packet should be transmitted, and if the AMR data packet should be transmitted, then transmitting the AMR data packet, or if the AMI data packet should be transmitted, then transmitting the AMI data packet. 
         [0009]    One advantage of the disclosed technique is that a utility meter may be deployed to operate within an AMR system, but later operate beneficially within an AMI system without requiring a service interruption or physical upgrade. 
         [0010]    Other embodiments include, without limitation, a computer-readable medium that includes instructions that enable a processing unit to implement one or more aspects of the disclosed methods as well as a system configured to implement one or more aspects of the disclosed methods. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. 
           [0012]      FIG. 1  illustrates a wireless network, configured to implement one or more aspects of the present invention; 
           [0013]      FIG. 2  is a block diagram of a dual mode smart grid meter, according to one embodiment of the present invention; 
           [0014]      FIG. 3  illustrates a digital radio subsystem, according to one embodiment of the present invention; and 
           [0015]      FIG. 4  is a flow diagram of method steps for providing metrology data via two orthogonal protocols, according to one embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    In the following description, numerous specific details are set forth to provide a more thorough understanding of the present invention. However, it will be apparent to one of skill in the art that the present invention may be practiced without one or more of these specific details. In other instances, well-known features have not been described in order to avoid obscuring the present invention. 
         [0017]      FIG. 1  illustrates a wireless network  100 , configured to implement one or more aspects of the present invention. Wireless network  100  may include an automatic meter reading (AMR) meter reader  116 , an advanced metering infrastructure (AMI) meter reader  118 , a dual mode smart grid meter  110 , an AMR meter  112 , and an AMI meter  114 . 
         [0018]    As shown, AMR meter reader  116  may passively accumulate meter readings from AMR meter  112  and dual mode smart grid meter  110  via wireless channel  120 , which conforms to AMR wireless protocol standards. Additionally, AMI meter reader  118  may query or control AMI meter  114  and dual mode smart grid meter  110  via wireless channel  122 , which conforms to AMI wireless protocol standards. 
         [0019]    Persons skilled in the art will recognize that a conventional AMI meter  114  is not readable via a conventional AMR meter reader  116 , while a conventional AMI meter reader  118  may not be operable within an AMR system. Dual mode smart grid meter  110  is configured to beneficially operate according to both AMR and AMI protocols. Dual mode smart grid meter  110  may be deployed within an existing AMR network without requiring operational changes by a utility operator. The utility operator may therefore incrementally upgrade their AMR networks by installing dual mode smart grid meters  110  at an appropriate pace without disrupting their existing AMR reading operations. The utility operator may then switch over to reading operations based on AMI when appropriate, such as after a certain region has been completely or substantially upgraded to AMI utility meters. In one embodiment, dual mode smart grid meter  110  is configured to operate as an AMR reader and an AMI meter. Here, the AMI meter functionality enables dual mode smart grid meter  110  to participate within an AMI network, such as a wireless AMI mesh network. In such an embodiment, dual mode smart grid meter  110  reads data from a collection of one or more AMR meters and presents the data to the AMI network. In this way, dual mode smart grid meter  110  may act as a bridge between the collection of one or more AMR meters and the AMI network. Any technically feasible technique may be implemented to represent the collection of one or more AMR meters to the AMI network without departing the scope and spirit of the present invention. 
         [0020]      FIG. 2  is a block diagram of dual mode smart grid meter  110  of  FIG. 1 , according to one embodiment of the present invention. Dual mode smart grid meter  110  comprises a processing unit, such as microprocessor unit (MPU)  260 , a digital radio subsystem  262 , a power subsystem  264 , an antenna  266 , a non-volatile memory  254 , volatile memory  256 , and a metrology subsystem  250 . Certain embodiments also comprise one or more additional elements, such as a control subsystem  252 . 
         [0021]    MPU  260  includes a processor core configured to retrieve and execute programming instructions from non-volatile memory  254 . In one embodiment, the instructions cause MPU  260  to perform as both an AMR meter and an AMI meter, as described below in  FIG. 4 . During the course of executing the programming instructions, the processor core may also store and retrieve data residing within the volatile memory  256 . Digital radio subsystem  262  comprises a radio receiver circuit  270 , configured to demodulate and digitize incoming RF electrical signals. Digital radio subsystem  262  also comprises a radio transmitter circuit  272 , configured to modulate a digital signal to generate RF electrical signals for transmission. In one embodiment, receiver circuit  270  and transmitter circuit  272  are implemented using a single RF conversion stage, and a digital signal processor, as described below in  FIG. 3 . 
         [0022]    Antenna  266  converts incident electromagnetic energy into the incoming RF electrical signals and also converts the RF electrical signals for transmission into radiated electromagnetic energy. Power subsystem  264  comprises regulation and power conversion circuitry configured to provide electrical voltage sources to each circuit and subsystem within dual mode smart grid meter  110 . Power subsystem  264  may also include an energy source such as a photovoltaic system, a battery, or fuel cell. In one embodiment, mode smart grid meter  110  includes a local area network interface configured to enable external devices to communicate to MPU  260 . 
         [0023]    Metrology subsystem  250  comprises circuitry configured to perform one or more measurements, such as voltage, current, power, accumulated power, flow rate, accumulated flow, temperature, humidity, vibration, or any other quantifiable physical value or metric. Metrology subsystem  250  quantizes measured results into corresponding digital values for processing and storage by MPU  260 . In one embodiment, metrology subsystem  250  comprises a power meter for measuring accumulated utilization of power. The control system  252  comprises one or more switches for controlling electrical signals. In one embodiment, control system  252  is a power switch for turning electrical power on or off, such as to enable service interruption and service continuation functionality within dual mode smart grid meter  110 . 
         [0024]      FIG. 3  illustrates digital radio subsystem  262  of  FIG. 2 , according to one embodiment of the present invention. Digital radio subsystem  262  may include, without limitation, a digital signal processor (DSP)  314 , digital to analog converters (DACs)  320 ,  321 , analog to digital converters (ADCs)  322 ,  323 , analog mixers  324 ,  325 ,  326 ,  327 , a phase shifter  332 , an oscillator  330 , a power amplifier (PA)  342 , a low noise amplifier (LNA)  340 , an antenna switch  344 , and antenna  266 . 
         [0025]    In one embodiment, the MPU  260  implements procedures for processing data packets transmitted or received as payload data by digital radio subsystem  262 . The procedures for processing the data packets may include, without limitation, wireless routing, encryption, authentication, protocol translation, and routing between and among different wireless and wired network ports. 
         [0026]    DSP  314  implements signal processing procedures for modulating a serialized representation of payload data comprising packets, such as data packets conforming to AMR transmission protocols or AMI transmission protocols. The serialized representation may encode one or more bits of payload data per modulation symbol or less than one bit per modulation symbol. A receiver may demodulate each modulation symbol to recover the one or more bits of payload data. In one embodiment the one or more bits of payload data are used to generate a corresponding data packet. 
         [0027]    DSP  314  may implement multi-channel modulation for simultaneous transmission of independent units of payload data via multiple, independent channels. Each independent channel occupies a different frequency range in a frequency domain representation of a transmitted radio signal. DSP  314  may also implement corresponding signal processing procedures for receiving payload data. The procedures may include, without limitation filtering, energy detection, signal characterization, and simultaneous demodulation of multiple, independent channels. 
         [0028]    In one embodiment, DSP  314  is configured to modulate data within a given channel using a particular modulation technique that is selected form a set of different modulation techniques. For example, DSP  314  may modulate data according to AMR specifications to generate a periodic data packet including metrology data. DSP  314  may also demodulate a signal from a given channel according to AMR specifications to act as an AMR receiver. Additionally, DSP  314  may be configured to perform modulation and demodulation signal processing according to AMI specifications to act as an AMI utility meter. DSP  314  or MPU  260  may be configured to translate AMR data read from a different utility meter into an equivalent representation for transmission via AMI protocols. Any technically feasible modulation, demodulation, filtering, energy detection, and signal characterization techniques may be implemented by DSP  314  without departing the scope and spirit of embodiments of the present invention. 
         [0029]    DSP  314  is coupled to DAC  320  and DAC  321 . Each DAC  320 ,  321  is configured to convert a stream of outbound digital values into a corresponding analog signal. The outbound digital values are computed by the signal processing procedures for modulating one or more channels. DSP  314  is also coupled to ADC  322  and ADC  323 . Each ADC  322 ,  323  is configured to sample and quantize an analog signal to generate a stream of inbound digital values. The inbound digital values are processed by the signal processing procedures to demodulate and extract payload data from the inbound digital values. 
         [0030]    In one embodiment, DSP  314  generates two modulated streams of outbound digital values, which are converted to corresponding analog quadrature signals by DACs  320 ,  321 . The analog quadrature signals are separately mixed with a radio frequency (RF) carrier signal by analog mixers  324 ,  325  to generate corresponding quadrature RF signals, each having a frequency domain image centered about the frequency of the RF carrier signal. Oscillator  330  generates the RF carrier signal and phase shifter  332  generates a 90-degree shifted representation of the RF carrier signal for generating quadrature RF signals. PA  342  combines the quadrature RF signals to generate a modulated RF signal, which is coupled through antenna switch  344  to the antenna  266 . Antenna  266  converts the modulated RF signal from an electrical representation to an electromagnetic representation for wireless transmission. 
         [0031]    Antenna  266  may convert an incoming electromagnetic RF signal to an electrical RF signal, which is coupled through the antenna switch  344  to the LNA  340 . LNA  340  amplifies the electrical RF signal and couples the amplified RF signal to analog mixers  326  and  327 . The amplified RF signal is characterized as having a signal image centered about an RF carrier frequency. The analog mixer  327  shifts the signal image down in frequency to an in-phase baseband component of the signal image. The signal is in-phase with respect to the RF carrier signal generated by oscillator  330 . Analog mixer  326  shifts the signal image down in frequency to a 90-degree shifted baseband component of the signal image. The in-phase and 90-degree shifted baseband signals comprise a quadrature representation of one or more channels within the electrical RF signal. A plurality of different frequency channels may be represented within the baseband signals. DSP  314  is configured to map the stream of inbound digital values, comprising a time domain representation of the baseband signals, to a frequency domain representation of the baseband signals. Persons skilled in the art will recognize that the frequency domain representation may be used to efficiently isolate one data bearing signal within one channel from a signal within a different channel. Similarly, the frequency domain representation may be used to detect noise and interfering transmissions within a given channel. 
         [0032]    In one embodiment, oscillator  330  can be programmed to generate one selected frequency from a plurality of possible frequencies. Each of the plurality of frequencies corresponds to a different channel. The selected frequency determines a center channel for a range of channels that are concurrently available for processing by DSP  314  to receive or transmit data. For example, if a frequency range of 4 MHz defines ten channels, then each channel is allocated a bandwidth of 400 kHz. In this example, a frequency range of 2,000 kHz representing five channels is processed by DSP  314  for transmitting or receiving data on one or more of the five channels. If oscillator  330  is programmed to generate a different selected frequency, then a different set of five concurrently available channels may be used for transmitting or receiving data. The center channel may be changed arbitrarily by programming oscillator  330  independently of DSP  314  operating on the concurrently available channels. Digital radio subsystem  262  may be configured with an arbitrary number of concurrently available channels, each having an arbitrary bandwidth without departing the scope and spirit of embodiments of the present invention. 
         [0033]      FIG. 4  is a flow diagram of method steps for providing metrology data via two orthogonal protocols, according to one embodiment of the invention. Although the method steps are described in conjunction with the systems of  FIGS. 1-3 , persons of ordinary skill in the art will understand that any system configured to perform the method steps, in any order, is within the scope of the invention. 
         [0034]    As shown, a method  400  begins in step  410 , where a dual mode smart grid meter, such as dual mode smart grid meter  110  of  FIG. 1 , performs an initialization procedure. The initialization procedure is implementation dependent and may include setting default values for subsequent operation, calibration steps, authentication steps, hardware configuration steps, and the like. When performed by dual mode smart grid meter  110 , the initialization procedure should include configuring digital radio subsystem  262  to receive AMI data packets. In alternative embodiments, dual mode smart grid meter  110  may implement a dedicated AMI receiver. 
         [0035]    If, in step  420 , an AMR transmission is needed then the method proceeds to step  424 . In one configuration, an AMR transmission timer indicates that an AMR metrology transmission is needed, when a specified time duration has lapsed. The AMR transmission timer may be implemented using any technically feasible technique. In step  424 , the dual mode smart grid meter transmits metrology data via an AMR protocol. Step  424  may include procedures that read metrology data from a measurement instrument and configure digital radio subsystem  262  for operation as an AMR transmitter. If, in step  440 , the method should terminate, then the method terminates, otherwise the method returns to step  420 . 
         [0036]    Returning now to step  420 , if an AMR transmission is not needed, then the method proceeds to step  430 . If, in step  430 , an AMI transmission is needed, then the method proceeds to step  432 . An AMI transmission may be required, for example, in response to AMI data being received via digital radio subsystem  262 . Such received AMI data may comprise a data packet to be forwarded from one AMI meter to another. Other received AMI data may comprise a read request from an AMI meter reader, such as AMI meter reader  118 . In another example, dual mode smart grid meter  110  is configured to read data from one or more AMR meters and transmit the data to an AMI wireless network. In such an example, an AMI transmission is needed to transmit data read from a remote AMR meter. In step  432 , the dual mode smart grid meter transmits outbound AMI data according to well-known AMI specifications. The outbound AMI data may comprise a data packet received via digital radio subsystem  262  to be forwarded to another AMI receiver. The outbound AMI data may also comprise a data packet generated as a response to a read request from the AMI meter reader. Step  432  may include procedures that read metrology data from a measurement instrument, and procedures that configure transmitter  272  within digital radio subsystem  262  to operate as an AMI transmitter to transmit the outbound AMI data. The outbound AMI data may also comprise a data packet generated in response to a control command, such as a command for operating a service interruption relay. The service interruption relay may turn power on or turn power off for a downstream client. The service interruption relay may also turn gas or water service on or off for a downstream client. 
         [0037]    Returning now to step  430 , if AMI data has not been received, then the method proceeds to step  440 , as previously described herein. 
         [0038]    In alternative embodiments, steps  420  and  430  may be performed in reverse priority so that responding to an AMI data packet received priority over periodic AMR metrology transmissions. 
         [0039]    In sum, a technique for implementing a dual mode smart grid meter is disclosed. The dual mode smart grid meter is configured to transmit AMR metrology data and to perform as an AMI smart grid meter. The technique involves determining whether to transmit a packet of AMR metrology data or to respond to an AMI request. A digital radio subsystem may be configured to transmit AMR data, transmit AMI data, and receive AMI data. 
         [0040]    One advantage of the disclosed technique is that a utility meter may be deployed to operate within an AMR system, but later operate beneficially within an AMI system without requiring a service interruption or physical upgrade. 
         [0041]    While the forgoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. For example, aspects of the present invention may be implemented in hardware or software or in a combination of hardware and software. One embodiment of the invention may be implemented as a program product for use with a computer system. The program(s) of the program product define functions of the embodiments (including the methods described herein) and can be contained on a variety of computer-readable storage media. Illustrative computer-readable storage media include, but are not limited to: (i) non-writable storage media (e.g., read-only memory devices within a computer such as CD-ROM disks readable by a CD-ROM drive, flash memory, ROM chips or any type of solid-state non-volatile semiconductor memory) on which information is permanently stored; and (ii) writable storage media (e.g., floppy disks within a diskette drive or hard-disk drive or any type of solid-state random-access semiconductor memory) on which alterable information is stored. Such computer-readable storage media, when carrying computer-readable instructions that direct the functions of the present invention, are embodiments of the present invention. 
         [0042]    In view of the foregoing, the scope of the present invention is determined by the claims that follow.