Abstract:
A method and system are provided to transmit a meter power status. The method includes recognizing a power status change at a meter. The method includes, if the meter is scheduled to transmit first, transmitting a notification message to at least one neighboring meter towards a mesh gate, wherein the notification message includes a power status indicator and a meter identifier. The method includes, if the meter is not scheduled to transmit first, waiting a predetermined time period to receive a notification message from at least one neighboring meter. The method includes, responsive to receiving a notification message, adding a meter identifier to the received notification message before retransmitting the modified notification message to at least one neighboring meter. The method includes retransmitting the notification message.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority to the following United States provisional patent applications which are incorporated herein by reference in their entirety:
         Ser. No. 60/989,957 entitled “Point-to-Point Communication within a Mesh Network”, filed Nov. 25, 2007;   Ser. No. 60/989,967 entitled “Efficient And Compact Transport Layer And Model For An Advanced Metering Infrastructure (AMI) Network,” filed Nov. 25, 2007;   Ser. No. 60/989,958 entitled “Creating And Managing A Mesh Network Including Network Association,” filed Nov. 25, 2007;   Ser. No. 60/989,964 entitled “Route Optimization Within A Mesh Network,” filed Nov. 25, 2007;   Ser. No. 60/989,950 entitled “Application Layer Device Agnostic Collector Utilizing ANSI C12.22,” filed Nov. 25, 2007;   Ser. No. 60/989,953 entitled “System And Method For Real Time Event Report Generation Between Nodes And Head End Server In A Meter Reading Network Including From Smart And Dumb Meters,” filed Nov. 25, 2007;   Ser. No. 60/989,956 entitled “System and Method for False Alert Filtering of Event Messages Within a Network”, filed Nov. 25, 2007;   Ser. No. 60/989,975 entitled “System and Method for Network (Mesh) Layer And Application Layer Architecture And Processes,” filed Nov. 25, 2007;   Ser. No. 60/989,959 entitled “Tree Routing Within a Mesh Network,” filed Nov. 25, 2007;   Ser. No. 60/989,961 entitled “Source Routing Within a Mesh Network,” filed Nov. 25, 2007;   Ser. No. 60/989,962 entitled “Creating and Managing a Mesh Network,” filed Nov. 25, 2007;   Ser. No. 60/989,951 entitled “Network Node And Collector Architecture For Communicating Data And Method Of Communications,” filed Nov. 25, 2007;   Ser. No. 60/989,955 entitled “System And Method For Recovering From Head End Data Loss And Data Collector Failure In An Automated Meter Reading Infrastructure,” filed Nov. 25, 2007;   Ser. No. 60/989,952 entitled “System And Method For Assigning Checkpoints To A Plurality Of Network Nodes In Communication With A Device Agnostic Data Collector,” filed Nov. 25, 2007;   Ser. No. 60/989,954 entitled “System And Method For Synchronizing Data In An Automated Meter Reading Infrastructure,” filed Nov. 25, 2007;   Ser. No. 61/025,285 entitled “Outage and Restoration Notification within a Mesh Network”, filed Jan. 31, 2008;   Ser. No. 60/992,312 entitled “Mesh Network Broadcast,” filed Dec. 4, 2007;   Ser. No. 60/992,313 entitled “Multi Tree Mesh Networks”, filed Dec. 4, 2007;   Ser. No. 60/992,315 entitled “Mesh Routing Within a Mesh Network,” filed Dec. 4, 2007;   Ser. No. 61/025,279 entitled “Point-to-Point Communication within a Mesh Network”, filed Jan. 31, 2008, and which are incorporated by reference.   Ser. No. 61/025,270 entitled “Application Layer Device Agnostic Collector Utilizing Standardized Utility Metering Protocol Such As ANSI C12.22,” filed Jan. 31, 2008;   Ser. No. 61/025,276 entitled “System And Method For Real-Time Event Report Generation Between Nodes And Head End Server In A Meter Reading Network Including Form Smart And Dumb Meters,” filed Jan. 31, 2008;   Ser. No. 61/025,282 entitled “Method And System for Creating And Managing Association And Balancing Of A Mesh Device In A Mesh Network,” filed Jan. 31, 2008;   Ser. No. 61/025,271 entitled “Method And System for Creating And Managing Association And Balancing Of A Mesh Device In A Mesh Network,” filed Jan. 31, 2008;   Ser. No. 61/025,287 entitled “System And Method For Operating Mesh Devices In Multi-Tree Overlapping Mesh Networks”, filed Jan. 31, 2008;   Ser. No. 61/025,278 entitled “System And Method For Recovering From Head End Data Loss And Data Collector Failure In An Automated Meter Reading Infrastructure,” filed Jan. 31, 2008;   Ser. No. 61/025,273 entitled “System And Method For Assigning Checkpoints to A Plurality Of Network Nodes In Communication With A Device-Agnostic Data Collector,” filed Jan. 31, 2008;   Ser. No. 61/025,277 entitled “System And Method For Synchronizing Data In An Automated Meter Reading Infrastructure,” filed Jan. 31, 2008;   Ser. No. 61/025,285 entitled “System and Method for Power Outage and Restoration Notification in An Automated Meter Reading Infrastructure,” filed Jan. 31, 2008; and   Ser. No. 61/094,116 entitled “Message Formats and Processes for Communication Across a Mesh Network,” filed Sep. 4, 2008.       

     This application hereby references and incorporates by reference each of the following United States nonprovisional patent applications filed contemporaneously herewith:
         Ser. No. 12/275,236 entitled “Point-to-Point Communication within a Mesh Network”, filed Nov. 21, 2008;   Ser. No. 12/275,305 entitled “Efficient And Compact Transport Layer And Model For An Advanced Metering Infrastructure (AMI) Network,” filed Nov. 21, 2008;   Ser. No. 12/275,238 entitled “Communication and Message Route Optimization and Messaging in a Mesh Network,” filed Nov. 21, 2008;   Ser. No. 12/275,242 entitled “Collector Device and System Utilizing Standardized Utility Metering Protocol,” filed Nov. 21, 2008;   Ser. No. 12/275,245 entitled “System and Method for False Alert Filtering of Event Messages Within a Network,” filed Nov. 21, 2008;   Ser. No. 12/275,252 entitled “Method and System for Creating and Managing Association and Balancing of a Mesh Device in a Mesh Network,” filed Nov. 21, 2008; and   Ser. No. 12/275,257 entitled “System And Method For Operating Mesh Devices In Multi-Tree Overlapping Mesh Networks”, filed Nov. 21, 2008.       

    
    
     FIELD OF THE INVENTION 
     This invention pertains generally to methods and systems for providing power outage and restoration notifications within an Advanced Metering Infrastructure (AMI) network. 
     BACKGROUND 
     A mesh network is a wireless network configured to route data between nodes within a network. It allows for continuous connections and reconfigurations around broken or blocked paths by retransmitting messages from node to node until a destination is reached. Mesh networks differ from other networks in that the component parts can all connect to each other via multiple hops. Thus, mesh networks are self-healing: the network remains operational when a node or a connection fails. 
     Advanced Metering Infrastructure (AMI) or Advanced Metering Management (AMM) are systems that measure, collect and analyze utility usage, from advanced devices such as electricity meters, gas meters, and water meters, through a network on request or a pre-defined schedule. This infrastructure includes hardware, software, communications, customer associated systems and meter data management software. The infrastructure allows collection and distribution of information to customers, suppliers, utility companies and service providers. This enables these businesses to either participate in, or provide, demand response solutions, products and services. Customers may alter energy usage patterns from normal consumption patterns in response to demand pricing. This improves system load and reliability. 
     A meter may be installed on a power line, gas line, or water line and wired into a power grid for power. During an outage, the meter may cease to function. When power is restored, meter functionality may be restored. 
     SUMMARY 
     A method and system provide power outage and restoration notifications within an AMI network. Mesh networks are used to connect meters of an AMI in a geographical area. Each meter may communicate with its neighbors via the mesh network. A mesh gate links the mesh network to a server over a wide area network (WAN). When a power outage occurs among the meters of a mesh network, leaf meters transmit outage messages first. Parent meters add a parent identifier before forwarding the outage messages. This reduces the number of transmitted outage messages within the mesh network. Similarly, restoration messages are transmitted from the leaf nodes first, while parent nodes piggy-back parent identifiers when forwarding the restoration messages from the leaf meters. 
     In one aspect, there is provided a system and method for power outage and restoration notification in an advanced metering infrastructure network. 
     In another aspect, there is provided a method of transmitting a meter power status, including: recognizing a power status change at a meter; if the meter is scheduled to transmit first, transmitting a notification message to at least one neighboring meter towards a mesh gate, wherein the notification message includes a power status indicator and a meter identifier; if the meter is not scheduled to transmit first, waiting a predetermined time period to receive a notification message from at least one neighboring meter; responsive to receiving a notification message, adding a meter identifier to the received notification message before retransmitting the modified notification message to at least one neighboring meter; and retransmitting the notification message. 
     In another aspect, there is provided a method of transmitting a network power status, including: receiving at least one notification message from a meter, wherein the notification message includes a power status indicator and at least one meter identifier; aggregating the received meter identifiers into a composite notification message, the composite notification message including a power status indicator and at least one meter identifier; transmitting the composite notification message to a server over a wide area network; and retransmitting the composite notification message. 
     In another aspect, there is provided a system for transmitting a network power status, including: (A) a mesh network; (B) a wide area network separate from the mesh network; (C) at least one meter in communication with the mesh network, the meter configured to: recognize a power status change at a meter, if the meter is scheduled to transmit first, transmit a notification message to at least one neighboring meter towards a mesh gate, wherein the notification message includes a power status indicator and a meter identifier, if the meter is not scheduled to transmit first, wait a predetermined time period to receive a notification message from at least one neighboring meter, responsive to receiving a notification message, adding a meter identifier to the received notification message before retransmitting the modified notification message to at least one neighboring meter, and retransmitting the notification message; (D) a mesh gate in communication with the meter over the mesh network and in communication with the wide area network, the mesh gate configured to: receive at least one notification message from a meter, wherein the notification messages include a power status indicator and at least one meter identifier, aggregate the received meter identifiers into a composite notification message, the composite notification message includes a power status indicator and at least one meter identifier, transmit the composite notification message to a server over a wide area network, and retransmitting the composite notification message; and (E) a server in communication with the mesh gate over the wide area network, the server configured to receive the composite notification message. 
     In another aspect, there is provided a system for transmitting a network power status, including: a mesh network; a wide area network separate from the mesh network; at least one meter in communication with the mesh network; a mesh gate in communication with the meter over the mesh network and in communication with the wide area network; and a server in communication with the mesh gate over the wide area network, the server configured to receive the composite notification message. 
     In another aspect, there is provided a computer program stored in a computer readable form for execution in a processor and a processor coupled memory to implement a method of transmitting a meter power status, the method including: recognizing a power status change at a meter; if the meter is scheduled to transmit first, transmitting a notification message to at least one neighboring meter towards a mesh gate, wherein the notification message includes a power status indicator and a meter identifier; if the meter is not scheduled to transmit first, waiting a predetermined time period to receive a notification message from at least one neighboring meter; responsive to receiving a notification message, adding a meter identifier to the received notification message before retransmitting the modified notification message to at least one neighboring meter; and retransmitting the notification message. 
     In another aspect, there is provided a computer program stored in a computer readable form for execution in a processor and a processor coupled memory to implement a method of transmitting a network power status, including: receiving at least one notification message from a meter, wherein the notification message includes a power status indicator and at least one meter identifier; aggregating the received meter identifiers into a composite notification message, the composite notification message including a power status indicator and at least one meter identifier; transmitting the composite notification message to a server over a wide area network; and retransmitting the composite notification message. 
     In another aspect, there is provided a method of transmitting a meter power status, including: recognizing a power status change at a meter; if the meter is scheduled to transmit first, transmitting a notification message from the meter to at least one neighboring meter towards a mesh gate, wherein the notification message includes a power status indicator and a meter identifier; if the meter is not scheduled to transmit first, waiting a predetermined time period to receive a notification message from at least one neighboring meter; responsive to receiving a notification message, adding a meter identifier to the received notification message before retransmitting the modified notification message to at least one neighboring meter, wherein the notification message includes a power status indicator and at least one meter identifier; aggregating the received meter identifiers into a composite notification message, the composite notification message including a power status indicator and at least one meter identifier; transmitting the composite notification message to a server over a wide area network; and retransmitting the composite notification message. 
     In another aspect, there is provided a computer program stored in a computer readable form for execution in a processor and a processor coupled memory to implement a method of transmitting a meter power status, the method including: recognizing a power status change at a meter; if the meter is scheduled to transmit first, transmitting a notification message from the meter to at least one neighboring meter towards a mesh gate, wherein the notification message includes a power status indicator and a meter identifier; if the meter is not scheduled to transmit first, waiting a predetermined time period to receive a notification message from at least one neighboring meter; responsive to receiving a notification message, adding a meter identifier to the received notification message before retransmitting the modified notification message to at least one neighboring meter, wherein the notification message includes a power status indicator and at least one meter identifier; aggregating the received meter identifiers into a composite notification message, the composite notification message including a power status indicator and at least one meter identifier; transmitting the composite notification message to a server over a wide area network; and retransmitting the composite notification message. 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an example system for providing AMI communications over a mesh network. 
         FIG. 2A  illustrates an example meter for use within a mesh network. 
         FIG. 2B  illustrates an example mesh gate for use within a mesh network. 
         FIG. 3  illustrates an example network stack for use within a mesh radio. 
         FIG. 4A  illustrates an example procedure for transmitting outage and restoration notifications from a meter within a mesh network. 
         FIG. 4B  illustrates an example procedure for transmitting outage and restoration notifications from a mesh gate within a wide area network. 
         FIG. 5A  illustrates a first timing of transmitting outage notifications from a meter within a mesh network. 
         FIG. 5B  illustrates a second timing of transmitting outage notifications from a meter within a mesh network. 
         FIG. 5C  illustrates a third timing of transmitting outage notifications from a meter within a mesh network. 
         FIG. 6  illustrates a timing of transmitting restoration notifications from a meter within a mesh network. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates an example system for providing AMI communications over a mesh network. A mesh network A  100  may include a mesh gate A  102  and a plurality of meters: meters A  104 , B  106 , C  108 , D  110 , E  112 , and F  114 . A mesh gate may also be referred to as a NAN-WAN gate or an access point. The mesh gate A  102  may communicate to a server  118  over a wide area network  116 . Optionally, a mesh gate B  120  and a mesh network B  122  may also communicate with the server  118  over the wide area network (WAN)  116 . Optionally, a mesh gate C  124  and a mesh network C  126  may also communicate with the server  118  over the wide area network  116 . 
     In one example embodiment, the server  118  is known as a “head end.” The mesh gate may also be known as a collector, a concentrator, or an access point. 
     It will be appreciated that a mesh device association can include a registration for application service at the mesh gate A  102  or the server  118 . The mesh gate A  102  and the server  118  can maintain a table of available applications and services and requesting mesh devices. 
     The mesh network A  100  may include a plurality of mesh gates and meters which cover a geographical area. The meters may be part of an AMI system and communicate with the mesh gates over the mesh network. For example, the AMI system may monitor utilities usage, such as gas, water, or electricity usage and usage patterns. 
     The mesh gate A  102  may provide a gateway between the mesh network A  100  and a server, discussed below. The mesh gate A  102  may include a mesh radio to communicate with the mesh network A  100  and a WAN communication interface to communicate with a WAN. 
     The mesh gate A  102  may aggregate information from meters within the mesh network A  100  and transmit the information to the server. The mesh gate A  102  may be as depicted below. It will be appreciated that while only one mesh gate is depicted in the mesh network A  100 , any number of mesh gates may be deployed within the mesh network A  100 , for example, to improve transmission bandwidth to the server and provide redundancy. A typical system will include a plurality of mesh gates within the mesh network. In a non-limiting embodiment for an urban or metropolitan geographical area, there may be between 1 and 100 mesh gates, though this is not a limitation of the invention. In one embodiment, each mesh gate supports approximately 400 meters, depending on system requirements, wireless reception conditions, available bandwidth, and other considerations. It will be appreciated that it is preferable to limit meter usage of bandwidth to allow for future upgrades. 
     The meters A  104 , B  106 , C  108 , D  110 , E  112 , and F  114  may each be a mesh device, such as a meter depicted below. The meters may be associated with the mesh network A  100  through direct or indirect communications with the mesh gate A  102 . Each meter may forward or relay transmissions from other meters within the mesh network A  100  towards the mesh gate A. It will be appreciated that while only six meters are depicted in the mesh network A  100 , any number of meters may be deployed to cover any number of utility lines or locations. 
     As depicted, only meters A  104  and D  110  are in direct communications with mesh gate A  102 . However, meters B  106 , E  112  and F  114  can all reach mesh gate A  102  through meter D  110 . Similarly, meter C  108  can reach mesh gate A  102  through meter E  112  and meter D  110 . 
     The wide area network (WAN)  116  may be any communication medium capable of transmitting digital information. For example, the WAN  116  may be the Internet, a cellular network, a private network, a phone line configured to carry a dial-up connection, or any other network. 
     The server  118  may be a computing device configured to receive information from a plurality of mesh networks and meters. The server  118  may also be configured to transmit instructions to the mesh networks, mesh gates, and meters. 
     It will be appreciated that while only one server is depicted, any number of servers may be used in the AMI system. For example, servers may be distributed by geographical location. Redundant servers may provide backup and failover capabilities in the AMI system. 
     The optional mesh gates B  120  and C  124  may be similar to mesh gate A  102 , discussed above. Each mesh gate may be associated with a mesh network. For example, mesh gate B  120  may be associated with mesh network B  122  and mesh gate C  124  may be associated with mesh network C  126 . 
     The mesh network B  122  and the mesh network C  126  may be similar to the mesh network A  102 . Each mesh network may include a plurality of meters (not depicted). 
     Each mesh network may cover a geographical area, such as a premise, a residential building, an apartment building, or a residential block. Alternatively, the mesh network may include a utilities network and be configured to measure utilities flow at each sensor. Each mesh gate communicates with the server over the WAN, and thus the server may receive information from and control a large number of meters or mesh devices. Mesh devices may be located wherever they are needed, without the necessity of providing wired communications with the server. 
       FIG. 2A  illustrates an example meter for use within a mesh network. A meter  200  may include a radio  202 , a communication card  204 , a metering sensor  206 , and a battery or other power or energy storage device or source  208 . The radio  202  may include a memory  210 , a processor  212 , a transceiver  214 , and a microcontroller unit (MCU)  216  or other processor or processing logic. 
     A mesh device can be any device configured to participate as a node within a mesh network. An example mesh device is a mesh repeater, which can be a wired device configured to retransmit received mesh transmissions. This extends a range of a mesh network and provides mesh network functionality to mesh devices that enter sleep cycles. 
     The meter  200  may be a mesh device communicating with a mesh gate and other mesh devices over a mesh network. For example, the meter  200  may be a gas, water or electricity meter installed in a residential building or other location to monitor utilities usage. The meter  200  may also control access to utilities on server instructions, for example, by reducing the flow of gas, water or electricity. 
     The radio  202  may be a mesh radio configured to communicate with a mesh network. The radio  202  may transmit, receive, and forward messages to the mesh network. Any meter within the mesh network may thus communicate with any other meter or mesh gate by communicating with its neighbor and requesting a message be forwarded. 
     The communication card  204  may interface between the radio  202  and the sensor  206 . Sensor readings may be converted to radio signals for transmission over the radio  202 . The communication card  204  may include encryption/decryption or other security functions to protect the transmission. In addition, the communication card  204  may decode instructions received from the server. 
     The metering sensor  206  may be a gas, water, or electricity meter sensor, or another sensor. For example, digital flow sensors may be used to measure a quantity of utilities consumed within a residence or building. Alternatively, the sensor  206  may be an electricity meter configured to measure a quantity of electricity flowing over a power line. 
     The battery  208  may be configured to independently power the meter  200  during a power outage. For example, the battery  208  may be a large capacitor storing electricity to power the meter  200  for at least five minutes after a power outage. Small compact but high capacity capacitors known as super capacitors are known in the art and may advantageously be used. One exemplary super capacitor is the SESSCAP 50 f 2.7 v 18×30 mm capacitor. Alternative battery technologies may be used, for example, galvanic cells, electrolytic cells, fuel cells, flow cells, and voltaic cells. 
     It will be appreciated that the radio  202 , communication card  204 , metering sensor  206  and battery  208  may be modular and configured for easy removal and replacement. This facilitates component upgrading over a lifetime of the meter  200 . 
     The memory  210  of the radio  202  may store instructions and run-time variables of the radio  202 . For example, the memory  210  may include both volatile and non-volatile memory. 
     The memory  210  may also store a history of sensor readings from the metering sensor  206  and an incoming queue of server instructions. 
     The processor  212  of the radio  202  may execute instructions, for example, stored in memory  210 . Instructions stored in memory  210  may be ordinary instructions, for example, provided at time of meter installation, or special instructions received from the server during run time. 
     The transceiver  214  of the radio  202  may transmit and receive wireless signals to a mesh network. The transceiver  214  may be configured to transmit sensor readings and status updates under control of the processor  212 . The transceiver  214  may receive server instructions from a server, which are communicated to the memory  210  and the processor  212 . 
     In the example of  FIG. 2A , the MCU  216  can execute firmware or software required by the meter  200 . The firmware or software can be installed at manufacture or via a mesh network over the radio  202 . 
     In one embodiment, any number of MCUs can exist in the meter  200 . For example, two MCUs can be installed, a first MCU for executing firmware handling communication protocols, and a second MCU for handling applications. 
     It will be appreciated that a mesh device and a mesh gate can share the architecture of meter  200 . The radio  202  and the MCU  216  provide the necessary hardware, and the MCU  216  executes any necessary firmware or software. 
     Meters may be located in geographically dispersed locations within an AMI system. For example, a meter may be located near a gas line, an electric line, or a water line entering a building or premise to monitor a quantity of gas, electricity, or water. The meter may communicate with other meters and mesh gates through a mesh network. The meter may transmit meter readings and receive instructions via the mesh network. 
       FIG. 2B  illustrates an example mesh gate for use within a mesh network. The mesh gate  230  may include a mesh radio  232 , a wide area network interface  234 , a battery  236 , and a processor  238 . The mesh radio  232  may include a memory  242 , a processor  244 , and a transceiver  246 . 
     The mesh gate  230  may interface between mesh devices (for example, meters) in a mesh network and a server. For example, meters may be as discussed above. The mesh gate  230  may be installed in a central location relative to the meters and also communicate with a server over a WAN. 
     The mesh radio  232  may be a mesh radio configured to communicate with meters over a mesh network. The radio  232  may transmit, receive, and forward messages to the mesh network. 
     The WAN interface  234  may communicate with a server over a WAN. For example, the WAN may be a cellular network, a private network, a dial up connection, or any other network. The WAN interface  234  may include encryption/decryption or other security functions to protect data being transmitted to and from the server. 
     The battery  236  may be configured to independently power the mesh gate  230  during a power outage. For example, the battery  236  may be a large capacitor storing electricity to power the mesh gate  230  for at least five minutes after a power outage. A power outage notification process may be activated during a power outage. 
     The processor  238  may control the mesh radio  232  and the WAN interface  234 . Meter information received from the meters over the mesh radio  232  may be compiled into composite messages for forwarding to the server. Server instructions may be received from the WAN interface  234  and forwarded to meters in the mesh network. 
     It will be appreciated that the mesh radio  232 , WAN interface  234 , battery  236 , and processor  238  may be modular and configured for easy removal and replacement. This facilitates component upgrading over a lifetime of the mesh gate  230 . 
     The memory  242  of the mesh radio  232  may store instructions and run-time variables of the mesh radio  232 . For example, the memory  242  may include both volatile and non-volatile memory. The memory  242  may also store a history of meter communications and a queue of incoming server instructions. For example, meter communications may include past sensor readings and status updates. 
     The processor  244  of the mesh radio  232  may execute instructions, for example, stored in memory  242 . Instructions stored in memory  242  may be ordinary instructions, for example, provided at time of mesh gate installation, or special instructions received from the server during run-time. 
     The transceiver  246  of the mesh radio  232  may transmit and receive wireless signals to a mesh network. The transceiver  246  may be configured to receive sensor readings and status updates from a plurality of meters in the mesh network. The transceiver  246  may also receive server instructions, which are communicated to the memory  242  and the processor  244 . 
     A mesh gate may interface between a mesh network and a server. The mesh gate may communicate with meters in the mesh network and communicate with the server over a WAN network. By acting as a gateway, the mesh gate forwards information and instructions between the meters in its mesh network and the server. 
       FIG. 3  illustrates an example network stack for use within a mesh radio. A radio  300  may interface with an application process  302 . The application process  302  may communicate with an application layer  304 , which communicates with a transport layer  306 , a network layer  308 , a data link layer  310  and a physical layer  312 . 
     The radio  300  may be a mesh radio as discussed above. For example, the radio  300  may be a component in a meter, a mesh gate, or any other mesh device configured to participate in a mesh network. The radio  300  may be configured to transmit wireless signals over a predetermined frequency to other radios. 
     The application process  302  may be an executing application that requires information to be communicated over the network stack. For example, the application process  302  may be software supporting an AMI system. 
     The application layer  304  interfaces directly with and performs common application services for application processes. Functionality includes semantic conversion between associated application processes. For example, the application layer  304  may be implemented as ANSI C12.12/22. 
     The transport layer  306  responds to service requests from the application layer  304  and issues service requests to the network layer  308 . It delivers data to the appropriate application on the host computers. For example, the layer  306  may be implemented as TCP (Transmission Control Protocol), and UDP (User Datagram Protocol). 
     The network layer  308  is responsible for end to end (source to destination) packet delivery. The functionality of the layer  308  includes transferring variable length data sequences from a source to a destination via one or more networks while maintaining the quality of service, and error control functions. Data will be transmitted from its source to its destination, even if the transmission path involves multiple hops. 
     The data link layer  310  transfers data between adjacent network nodes in a network, wherein the data is in the form of packets. The layer  310  provides functionality including transferring data between network entities and error correction/detection. For example, the layer  310  may be implemented as IEEE 802.15.4. 
     The physical layer  312  may be the most basic network layer, transmitting bits over a data link connecting network nodes. No packet headers or trailers are included. The bit stream may be grouped into code words or symbols and converted to a physical signal, which is transmitted over a transmission medium, such as radio waves. The physical layer  312  provides an electrical, mechanical, and procedural interface to the transmission medium. For example, the layer  312  may be implemented as IEEE 802.15.4. 
     The network stack provides different levels of abstraction for programmers within an AMI system. Abstraction reduces a concept to only information which is relevant for a particular purpose. Thus, each level of the network stack may assume the functionality below it on the stack is implemented. This facilitates programming features and functionality for the AMI system. 
       FIG. 4A  illustrates an example procedure for transmitting outage and restoration notifications from a meter within a mesh network. A mesh device, such as a meter, may include a sensor for measuring utilities and receive power from a power grid. At times, the power grid may fail during a power outage. The power grid may also be restored after an outage. The meter may include a battery configured to power the meter for a period of time, during which the meter executes a power outage notification procedure to inform a mesh gate and a server of the power outage. Similarly, the meter may execute a power restoration notification when functionality is restored after power is restored to the power grid. 
     In  400 , the meter may detect a power status change. For example, the meter may include an electric sensor sensing a power, current, or voltage of an electric line powering the meter from a power grid. When the sensor senses a cut-off in electricity, the meter may wait a predetermined recognition period before determining that a power outage has occurred. 
     When a meter&#39;s power is restored after an outage, the meter may also wait a predetermined recognition period before determining that the power outage has ended and power has been restored. Using a recognition period before an outage or a restoration has occurred prevents the meter from trigging the notification procedure for brief outages and restorations. 
     In  402 , the meter tests whether it is the first to transmit. For example, the meter may look up a neighborhood table to determine whether it is a leaf meter. A leaf meter may have no children meters, and is thus the last meter on its associated branch. For example,  FIG. 1  depicts meters A  104 , B  106 , C  108 , and F  114  as leaf meters. Meter F  114  is a leaf meter because no child meter would transmit through it to reach mesh gate A  102 , even though meter F  114  has two alternate paths to the mesh gate A  102  (F  114  to E  112  to D  110  to mesh gate or F  114  to D  110  to mesh gate). 
     A one-hop device, which can be a device in direct communications with the mesh gate, may transmit immediately. 
     Alternatively, the meter may look up the neighborhood table to determine a number of hops to the mesh gate. If it is farthest from the mesh gate on its branch, it will transmit first. If the meter determines yes, the meter proceeds to  404 . If no, the meter proceeds to  410 . The neighborhood table can be built during association requests and subsequent neighbor exchanges. 
     In  404 , the meter may transmit a notification message. The notification message may include a nature of the notification (whether a power outage or restoration has occurred, as determined in  400 ) and a meter identifier. The meter identifier may be a globally unique identifier assigned to the meter at manufacture or installation that identifies the meter to the mesh gate and the server. 
     If the notification message has previously been transmitted, the meter may attempt a retry transmission. Retries may be attempted until an acknowledgement is received or a predetermined number of retry attempts has been exceeded. 
     Information transmitted in the transmission may include a device identifier, a time of outage, and any other necessary information. In one embodiment, a number of transmitted neighbor information may be restricted. For example, only a predetermined maximum number of parents, siblings, and children node information can be transmitted to limit message size. Neighbors can be selected based on a preferred route ratio. Neighbors that are on a preferred route of a meter&#39;s path to the mesh gate may be prioritized. The preferred route ratio can be used to select routes with a minimum of hops over a best minimum signal quality link to the mesh gate. 
     In  406 , the meter may test whether it has exceeded a predetermined retry attempts. The meter may increment a counter for a number of retries after every attempt to transmit a notification message in  404 . The predetermined retry attempts may be set to limit network congestion, both within the mesh network and over a WAN from a mesh gate to the server during a power outage and restoration. 
     Alternatively, the meter may continually attempt to transmit until its battery is drained during a power outage notification procedure. This may be used in an AMI system where it is important to receive as many accurate outage notifications as possible, or where network bandwidth is of lesser concern. If the predetermined retry attempts have been exceed, the procedure ends. If no, the meter procedures to  408 . 
     In  408 , the meter optionally delays a random time period. For example, the delay may allow other meters in the mesh network to transmit and reduce collisions. Further, the delay may improve battery life after a power outage. 
     The random time period may be associated with a predetermined floor value, below which it cannot be set. This may be an exclusion period during which no retransmission may be attempted by the meter. 
     In  410 , the meter tests whether a child message has been received. For example, a non-leaf meter will not transmit during a first attempt, and may receive notification messages from child meters. If yes, the meter proceeds to  412 . If no, the meter proceeds to  404 . In one embodiment, if the meter determines it has missed the child messages, it may immediately transmit its message. 
     In  412 , the meter may insert a meter identifier in the notification message. The notification message received from the child meter in  410  may include a status (whether the notification is for a power outage or restoration) and at least one meter identifier associated with children meters. The meter may insert its own identifier into the message before forwarding the message in  404 . 
     By executing the procedure above, leaf meters transmit notification messages first. Each meter waits to receive a notification message from children meters before adding its identifier and forwarding the notification to its parent meter. This reduces message congestion in the mesh network during a notification procedure. 
     In an alternative example, each parent meter may determine how many children meters it has, and wait for notification messages from all children meters before compiling the messages into one message to be forwarded. Alternatively, the parent meter may wait for a predetermined period of time, because only some children meters may be affected by a power outage. 
     It will be appreciated that if a meter has not suffered a power outage, it would simply forward any received notification messages to its parent without adding its identifier into the message. Similarly, if a parent meter has not had a power restoration; it will remain off and be unable to forward notification messages. In this example, children meters may attempt alternative routes to transmit notification messages, as discussed below. 
       FIG. 4B  illustrates an example procedure for transmitting outage and restoration notifications from a mesh gate within a wide area network. A mesh gate and its associated mesh devices, such as meters, may receive power from a power grid. At times, the power grid may fail during a power outage. The power grid may also be restored after an outage. The mesh gate may include a battery configured to power the mesh gate for a period of time, during which the mesh gate executes a power outage notification procedure to inform a server of the outage and affected meters. Similarly, the mesh gate may execute a power restoration notification when power is restored to the power grid. 
     In  450 , the mesh gate may receive a notification message from a meter within its mesh network. For example, the notification message may include a status indicating whether it is an outage or restoration notification and at least one meter identifier. The notification message may be as discussed above. 
     In  452 , the mesh gate may test whether it has finished receiving notification messages from the mesh network. For example, the mesh gate may continually receive notification messages until its battery drops to a critical level during an outage. The critical level may be set to where enough power remains in the battery to allow the mesh gate to transmit its composite notification message to the server, as discussed below, along with a predetermined number of retries. 
     Alternatively, the mesh gate may wait for a predetermined time period after receiving a first notification message. For example, the predetermined time period may be determined, in part, based on the size of the mesh network, the maximum number of hops to reach a leaf meter, the link quality of the mesh network, etc. 
     Alternatively, the mesh gate may proceed as soon as message notifications from all children meters within the mesh network have been received. If all children meters are accounted for, the mesh gate does not need to wait for further notification messages. 
     If the mesh gate has finished receiving notification messages, it may proceed to  454 . If no, it may proceed to  450  to await more notification messages. 
     In  454 , the mesh gate may select a power reporting configuration. For example, two power reporting configurations may be available: one used for minor outage, such as one affecting only a few meters, and one used for major outages, such as one affecting many meters. The power reporting configuration may affect the retry attempts and delay periods discussed below. 
     For example, it may be very important to inform the server of a major outage. Thus, a high number of retry attempts may be set. It may be likely that a major outage has affected other mesh networks. Thus, a longer delay period may be used to reduce transmission collisions over the WAN. In addition, a longer window may be set to wait for notification messages from meters. 
     In  456 , the mesh gate may aggregate all the notification messages into a composite notification message. For example, the mesh gate may create the composite notification message containing a status indicating whether an outage or restoration has occurred in the mesh network and a list of meter identifiers associated with the notification. For example, the list of meter identifiers may be received in  452  from one or more meters. 
     In one example, the mesh gate may receive both an outage and a restoration notification message. The mesh gate may aggregate a first notification message, for example, all received outage notification messages, for transmission. Then, the mesh gate may aggregate a second notification message, for example, the restoration notification message for transmission. 
     In  458 , the mesh gate may transmit the composite notification message to the server over a WAN. For example, the WAN may be a cellular network, a wired network, or another network configured to carry information. In one example, the WAN used to transmit the composite notification message may be a secondary communications medium. A primary wired network may fail during a power outage, and therefore a backup network may be used. For example, the backup network may be a battery-powered network, cellular network, a battery-powered wired network, or another network configured to operate during an outage. 
     If the composite notification message has previously been transmitted, the mesh gate may attempt a retry transmission. Retries may be attempted until an acknowledgement is received or a predetermined number of retry attempts has been exceeded. 
     In  460 , the mesh gate may test whether a predetermined number of retry attempts has been exceeded. The mesh gate may increment a counter for a number of retries after every attempt to transmit a notification message in  458 . The predetermined retry attempts may be set to limit network congestion over the WAN to the server during a power outage and restoration. 
     Alternatively, the mesh gate may continually attempt to transmit until its battery is drained during a power outage notification procedure. This may be used in an AMI system where it is important to receive as many accurate outage notifications as possible, or where network bandwidth is of lesser concern. 
     For example, the predetermined number of retry attempts may be set in part based on the power reporting configuration selected in  454 . If the predetermined number of retry attempts has been exceeded, the mesh gate may end the procedure. If no, the mesh gate may proceed to  462 . 
     In  462 , the mesh gate may optionally delay a random time period. For example, the delay may allow other mesh gates in the WAN to transmit and reduce collisions. Further, the delay may improve battery life after a power outage. 
     For example, the delay period may be set in part based on the power reporting configuration selected in  454 . The random time period may be associated with a floor value, below which it cannot be set. This may be an exclusion period during which no retransmission may be attempted. 
     The mesh gate may aggregate all notification messages sent to it by meters over the mesh network. The composite notification message consists of a power status and a list of meter identifiers identifying the meters affected by the power status. The composite notification message may be transmitted over an outage-resistant communications link to a server. 
       FIG. 5A  illustrates a first timing of transmitting outage notifications from a meter within a mesh network. A power outage notification process allows orderly transmission of power outage notification from one or more mesh devices (such as a meter) in a mesh network to a mesh gate. The mesh gate aggregates the notifications and transmits a composite message to a server. Because the mesh network may include a large number of meters, transmitting individual notifications from each meter may cause network congestion, especially because other meters within the mesh network are also likely affected by the same outage and will also be sending outage notifications. 
     A recognition period (e.g., RECOGNITION_PERIOD) may elapse between an occurrence of a power outage and time T 1 , when the power outage is recognized by the meter. The recognition period may prevent minor power fluctuations or outages from triggering the outage notification procedure. 
       FIG. 5B  illustrates a second timing of transmitting outage notifications from a meter within a mesh network. The meter may wait for a first random period before a first attempt to send a power outage notification at time T 2 . A first attempt wait period (e.g., PO_RND_PERIOD) may represent a maximum random delay in seconds used before the first attempt. This random delay starts after recognition period (RECOGNITION_PERIOD) elapses at time T 1 . The first attempt is reserved for leaf meters. A meter which is not a leaf meter will not transmit during the first attempt. 
     The meter may wait for a retry random period before a retry attempt at time T 3 . A retry wait period (e.g., PO_RETRY_RND_PERIOD) may represent a maximum random delay in seconds used for each retry. This random delay starts after time T 2 , when a first transmission attempt occurs. 
     Using a random delay before the first and retry attempts prevents colliding transmission from multiple meters and reduces network congestion. If a meter attempts to transmit but a transmission is already in progress, the meter may wait for the transmission in progress to end before attempting to transmit. 
     If a meter receives a notification from a child meter, its transmission includes the child&#39;s notification plus the meter&#39;s identifier. By piggy-backing the meter&#39;s identifier in a child&#39;s notification and forwarding the notification, the number of individual notifications and messages are reduced in the mesh network. 
     The meter may continually retry to transmit an outage notification until the meter&#39;s battery is drained. In addition, there may be a predetermined maximum number retries. In addition, there may be a minimum period for the first delay and the subsequent retry delays. The minimum delay periods may eliminate the possibility of immediate retransmissions and guarantee a minimum delay between attempts. 
     The mesh gate may receive all the power outage notification messages and compile the information into a message for transmission to a server over a WAN. The mesh gate may also retransmit the compiled notification as necessary, until its battery is drained. 
     Child meters in a mesh network transmit outage notifications first, and parent meters piggy-back meter identifiers into the child notifications before forwarding the child notifications. A number of messages and notifications transmitted in the mesh network during an outage are thereby reduced. 
       FIG. 6  illustrates a timing of transmitting restoration notifications from a meter within a mesh network. A power restoration notification process allows orderly transmission of power restoration notification messages from one or more mesh devices (such as a meter) in a mesh network to a mesh gate. The mesh gate aggregates the notifications and transmits a composite message to a server. Because the mesh network may include a large number of meters, transmitting individual notifications from each meter may cause network congestion, especially because other meters within the mesh network are also likely affected by the restoration and will also be sending restoration notifications. 
     When power is restored at a meter, the meter may first wait for a recognition period before deciding the power has been restored. The recognition period may prevent triggering restoration notifications when power returns for a brief moment before the outage continues. 
     A first random period, PR_RND_PERIOD, may represent a maximum random delay used before a first attempt is made to send a power restoration notification. This first random period may begin after the power restored recognition period, PR_RECOGNITION_PERIOD. A first notification may be transmitted. Only leaf meters transmit during the first attempt. 
     A retry random period, PR_RETRY_RND_PERIOD, may represent a maximum random delay before a retry to send a power restoration notification. The retry random period begins after the first random period. 
     Using a random delay before the first and retry attempts reduces colliding transmission from multiple meters. If a meter attempts to transmit but a transmission is already in progress, the meter may wait for the transmission to end before attempting to transmit. 
     Referring to  FIG. 5C , after the first attempt to transmit has been made, the mesh gate may wait a minimum delay (e.g., MIN_DELAY) to time T 4  and an additional random period (e.g., RAND_PERIOD) to time T 5  before retrying transmission. Each retry attempt may be preceded by a retry random period (e.g., RETRY_RND_PERIOD) to time T 6 , and a maximum number of retry attempts may be set at maximum retries (e.g., MAX_RETRIES). The procedure may stop at time T 7 , after all retry attempts have been made. 
     If a meter receives a notification from a child meter, its transmission includes the child&#39;s notification plus the meter&#39;s identifier. By piggy-backing the meter&#39;s identifier in a child&#39;s notification and forwarding the notification, the number of individual notifications and messages are reduced in the mesh network. 
     The mesh gate may receive all power restoration notification messages and compile the information into a composite message for transmission to a server over a WAN. Similarly, the mesh gate may also repeatedly attempt to transmit the composite restoration message until a maximum number of retries have been made or the server acknowledges the transmission. 
     Child meters in a mesh network transmit restoration notifications first, and parent meters piggy-back meter identifiers into the child notifications before forwarding the child notifications. A number of messages and notifications transmitted in the mesh network during a restoration are thereby reduced. 
     If a child meter attempts to forward a message to a parent meter that is not functional (for example, the parent meter&#39;s power has not been restored); the child meter may wait a predetermined period of time. If the parent meter remains non-functional, the child meter may attempt to send its notification via an alternative path through the mesh network stored in its memory. If that fails, the child meter may attempt to discover a new route through the mesh network to the mesh gate. If that fails, the child meter may attempt to associate with a new mesh network in order to transmit its restoration notification message. 
     Although the above embodiments have been discussed with reference to specific example embodiments, it will be evident that the various modification, combinations and changes can be made to these embodiments. Accordingly, the specification and drawings are to be regarded in an illustrative sense rather than in a restrictive sense. The foregoing specification provides a description with reference to specific exemplary embodiments. It will be evident that various modifications may be made thereto without departing from the broader spirit and scope as set forth in the following claims. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense.