Coordinating power distribution line communications

COORDINATION OF COMMUNICATIONS ON AENERG1EL ™ DISTRIBUTION LINES

ELECTRICAL

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This patent document claims the priority of US patent application 13/334502, filed on December 22, 2011, the content of which is fully included by reference.

TECHNICAL STAGE

Service providers use distributed networks in order to provide services to customers placed across large geographical areas. For example, electricity companies use electricity distribution lines to transport electricity from one or more power stations (power plants) to customers in residential or commercial complexes alike. Power stations use alternating current (AC) to transmit electricity over long distances through power distribution lines. Long distance transport can be achieved by using a relatively high voltage level. Substations located near the locations where the customers are located lower the voltage level, more precisely the high voltage transforms it into low voltage (for example, using transformers). Electricity distribution lines carry this low alternating voltage from substations to consuming devices in locations where customers are.

Communications providers may use a distributed communications network to provide customer communications services. Similarly, energy companies use power grid lines, measuring devices, and other network elements to provide electricity to customers across an entire geographic area and to receive data from customer locations (for example, including , but not limited to, data representing the degree of utilization of the measured utility). A system can provide reporting functions using a set of data collection devices (collectors) that are designed to communicate with nearby consumer devices. However, data communication between the command center, collectors and many thousands of consuming devices along power distribution lines can be a particular problem.

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difficult. The large number of consumer devices account ύ \ "2 0 14-0 Ο 47 6

4 “12- 2fli2 problems, including synchronization, communication bandwidth and cost concerns. Other issues that may arise are related to signal interference and coordination between communicating devices.

BRIEF PRESENTATION OF THE INVENTION

BACKGROUND OF THE INVENTION The present invention relates to systems and methods that can be used in conjunction with coordinated data communications between devices and through power distribution lines. These and other aspects of the present invention are exemplified by illustrating a number of examples of implementations and applications, some of which are presented in figures and characterized in the following claims chapter.

Coordination of data communications between a device that distributes data, such as a collector device, and many other devices that represent end points of consumption, through power distribution lines can be a very difficult problem. For some applications, the large number of consuming devices can contribute to a number of issues, including synchronization, communication bandwidth and cost concerns. These and other aspects may be appreciated in connection with one or more embodiments discussed herein.

Concrete embodiments of the present invention may include different methods and devices. In accordance with the present disclosure, certain embodiments are directed to a method used to coordinate data communications between multiple consumer devices and multiple collectors. The communications between these consuming devices and the collectors are made through the lines of distribution of electricity (lines that carry electricity using alternating current (AC)). Within this method of coordinating communications, the data are communicated along the lines of distribution of electricity, from the devices responsible for collecting the data (collecting devices) to the devices representing the end points of consumption, by using a protocol that is defined by a first and two synchronization. The first and second synchronization can be used to indicate the time when the frames will be transmitted, respectively, the time when the symbols in the frames will be transmitted. Furthermore, the method includes generating a

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CY2 O 1 4 - OO 47 6 i 4 -U- 2012 local) and, using the clock of the collector device as a time base, maintaining a network collection time. In certain embodiments, the first synchronization is determined by the collection time corresponding to the network (from the level of each collector device). In addition, at the level of each collector device, the frequency of the alternating current transported through the electricity distribution lines can be monitored. The second synchronization is determined based on the monitored frequency. In addition, the method, in the present embodiment, includes adjusting a network time corresponding to the end point of consumption, at the level of each device representing an end point of consumption, in accordance with the time indicated by the data packets received from a device collecting.

In certain embodiments of the present invention, this method may be used to coordinate data communications which may include further steps. For example, the method may also include calculating the time between the end of a first data frame (determined by the second synchronization) and the beginning of a second data frame (determined by the first synchronization). An additional step of determining the number of synchronization symbols that can be transmitted before the start of the second frame is also included in the time calculation step between the end of the first frame and the beginning of the second. The number of synchronization symbols is determined based on the transmission rate of the symbols for the first frame and the calculated time. Network times, used in this method, can be periodically adjusted according to a standard maintained external time.

In other embodiments of the invention, the first synchronization defines the time when the data frames are transmitted and then the data symbols are transmitted according to the alternating current (for example, the periodicity of a symbol is adjusted based on a frequency corresponding to the alternating current. ). The data symbols used in this method can be encoded using, as a non-limiting example, quadrature phase shift keying (QPSK). For embodiments using QPSK or other encoding protocols, AC may be used as a time basis for periodic / repeated execution of a software code module, such as an interrupt service routine (ISR). , which monitors an alternating current signal value. This code / ISR can be run repeatedly at a fast enough speed

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4 -β- 2012 synchronization for QPSK encoded symbols, the synchronization being relatively a consumer device that uses another interrupt routine to generate a time base corresponding to the alternating current used to decode the symbols.

Embodiments of the present disclosure are also directed to a method that includes maintaining a transmission period characterized by a start time and an end time synchronized with the network time. In addition, this method, in response to the start time, begins the transmission of a frame, which includes a plurality of symbols. The transmission takes place along some distribution lines that carry electricity using alternating current. This method also includes synchronizing a transmission time for each symbol in the plurality of symbols with a signal transition corresponding to the alternating current. In response to reaching the end of the frame, a period of symbol synchronization is determined for a synchronized adjusted symbol, based on transmission times, for the plurality of symbols, and the time between the end of the frame and the end of time. The adjusted synchronization symbol is then transmitted through the power distribution lines.

In certain specific embodiments of this method, each symbol in the plurality of symbols has a common symbol period. In addition, the symbol period of the synchronization symbol is shorter than the common symbol period. The symbol, from the plurality of symbols, in certain embodiments of this method, are further defined as having a common symbol period. In these cases, a symbol synchronization period is determined based on a number of symbols of the common symbol period that can be transmitted between the end of the frame and the end of time.

Embodiments of the present invention are also directed to a device that includes a network time clock circuit, a system time clock circuit and a processing circuit. The network clock circuit of this device is sensitive to a daily network time and the system time clock circuit is sensitive to an AC frequency that crosses the power distribution lines. The processing circuit is designed to determine a transmission period provided with start and end times determined using the network time clock. Furthermore, the processing circuit is configured to start transmission of a frame, which includes a plurality of symbols, in response to the start time, through the lines / '/' r 'f ·' '⁴

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4 -12- 2012 distribution of electricity that transports energy using AC power. The processing circuit is designed to synchronize a transmission time for each symbol in the plurality of symbols with the system time clock. In response to reaching the end of the frame, the processing circuit is designed to determine the symbol length for the synchronization symbol based on the time between the end of the frame and the final time as well as the transmission times for the plurality of symbols. The processing circuit is configured to then transmit the synchronization symbol through the power distribution lines.

The above brief presentation of the invention is not intended to describe each embodiment or each implementation of the present invention. The following figures and detailed description, including what is presented in the claims chapter, set out in more detail some of these embodiments.

BRIEF DESCRIPTION OF THE FIGURES

Various embodiments of the present invention may be better understood by considering the detailed description which follows with the accompanying figures, which represent:

FIG. 1 is a block diagram of an example network environment in which the devices representing the endpoints of consumption communicate data with the data collection units, in accordance with the embodiments of the invention set forth in the present description;

FIG. 2 shows a block diagram of a communications coordination device for the electricity distribution lines, in accordance with the embodiments of the invention set out in the present description;

FIG. 3 shows a time diagram for frames transmitted through the power distribution lines, in accordance with the embodiments of the invention set out in the present description;

FIG. 4 shows a time diagram for coordinated data transmissions, according to the embodiments of the invention set forth in the present description;

FIG. 5 shows a flow chart for an ISR, according to the embodiments of the invention set forth in the present description;

FIG. 6 shows a flow chart for an ISR, corresponding to an alternating current transmission line, which can be used to determine the frequency ^

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4 -12 · 2012 average of the AC line, according to the embodiments of the invention set out in the present description.

Although the description can be improved with various modifications and alternative forms, examples of them have been presented through the embodiments in the figures and will be described in detail. It should be understood that, however, the intention is not to limit the disclosure of the invention to the particular embodiments of the invention presented and / or described. On the contrary, the intention is to cover all the modifications, equivalences and alternatives that fall within the spirit and purpose of the disclosure of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Aspects of the present disclosure are considered to be applicable to a variety of different types of devices, systems and arrangements for coordinating data communications between multiple levels of devices that use electricity distribution lines as information carriers. While this description is not necessarily limited to such applications, different aspects of the disclosure can be appreciated through discussion of different examples using this context.

A particular use of communications with electricity lines refers to applications for reading utility meters. In utility meter reading applications (as well as in other applications), there may be millions of endpoints that offer coordinated readings. Downstream communication to so many end points of consumption is a difficult task that is made difficult by the communication constraints caused by the use of electricity distribution lines. For example, there may be constraints related to the interference introduced by the harmonics caused by the AC (AC) in the power distribution lines. For reporting utility consumption and the associated billing function, time spent over a day can be an important element. In addition, the communication protocols between the different communication levels specific to the communication devices may require time-dependent coordination between devices.

Requests for coordinating system synchronization can be significant with increasing bandwidth (for example, due, at least in part, to constraints caused by the use of electricity distribution lines). Aspects of the presentU - // jl &lt;_£ uX '\ v6; '&gt;! * J (' r

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The descriptions, although not necessarily limited to the characterizations and problems mentioned above, are directed directly to the coordination of communications towards the final points of consumption. These communications can use different time bases and can modify the communication protocol according to these differences.

Aspects of the present disclosure take into account that transmitting the symbols based on a local oscillator may prevent the reception of a downstream signal at the level of a final consumption point. This may also cause intermodular harmonics in relation to the carrier frequency. Other aspects of the present disclosure take into account the fact that the use of a clock symbol based solely on the frequency of the alternating current can create a series of communication problems related to time when coordinating the communications between a plurality of final consumption points.

Examples of embodiments of the present invention include various methods, devices and systems. In accordance with the present description, certain embodiments are directed to a method used to coordinate communications between multiple devices that represent endpoints of consumption and multiple devices responsible for data collection. The communications between these devices that represent the end points of consumption and the devices responsible for the data collection take place through the electricity distribution lines (which transport electricity using AC power). Within this method for coordinating communications, data is transmitted through power distribution lines, from data collection devices to devices representing endpoints of consumption, using a protocol that is defined by a first and a second synchronization. . The first synchronization indicates the time corresponding to the transmission of the data frames and the second synchronization defines the time when the symbols in the data frames are transmitted. Moreover, at each data collector device, the method includes generating a clock (for example, using a local oscillator circuit) and, using the clock of the collector device as a time base, maintaining a network collection time. The first synchronization is determined by the collection time corresponding to the network (from the level of each collector device). In addition, at the level of each collector device, the frequency of the alternating current transmitted through the electricity distribution lines can be monitored. The second synchronization is determined based on the monitored frequency. in addition, the method, / 'ÎL'⁷ / Î'fi

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4 -12- 2012 example of this embodiment, includes the adjustment of a network time corresponding to the end point of consumption, at the level of each device representing an end point of consumption, in accordance with the time indicated by the data packets received from a collector device.

In certain embodiments, the method may also include the calculation of the time between the end of a first data frame (determined by the second synchronization) and the beginning of a second data frame (determined by the first synchronization). An additional step of determining the number of synchronization symbols that can be transmitted before the beginning of the second frame is also included in the step of calculating the time between the end of the first frame and the beginning of the second frame. The number of synchronization symbols is determined based on a symbol transmission rate for the first frame and based on the calculated time. The network time can be adjusted according to an external time maintained standard, in certain embodiments.

In other embodiments of the invention, the first synchronization defines the time frame at which the data frames are transmitted and then the data symbols are transmitted according to a time-dependent parameter characteristic of the alternating current (for example, in response at a detected frequency of the alternating current). The data symbols used in this method, useful for coordinating communications, in other embodiments are coded using the QPSK quadrature phase shift keying technique. For embodiments using QPSK, the frequency of the alternating current can be monitored by repeatedly (or periodically) executing a code (for example, by running an interrupt routine or a selection routine) in order to detect a signal value. alternative current. The signal value may include, but is not limited to, a voltage switch case (by zero value / by a non-zero value), a rising / falling edge, or sensing a peak value (minimum / maximum). For simplicity, this repetitive code will be referred to as an interrupt routine. This interrupt routine is called with a frequency large enough to provide synchronization for the QPSK encoded symbols to be decoded at the endpoint of consumption which uses its own interrupt routines to detect an alternate current signal value. The final point of

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4 -12- 2012 consumption can be used to detect the value of the signal in order to determine the frequency of the alternating current.

Embodiments of the present invention are also directed to a method that includes maintaining a transmission period characterized by a start time and a closing time, both synchronized with the network time. Moreover, this method, depending on the start time, begins the transmission of a data frame that includes a plurality of symbols. This transmission takes place through the distribution lines that transport electricity using AC power. This method also includes synchronizing a transmission time for each symbol in the plurality of symbols with an appropriate transition of the AC signal. In response to reaching the end of the data frame, a symbol synchronization period is determined for an adjusted synchronization symbol, based on transmission times, for the plurality of symbols and according to the time between the end of the frame and the end of time. The adjusted timing symbol is then transmitted through the power distribution lines.

In certain embodiments of the present method, each symbol in the plurality of symbols has a common symbol period. In addition, the symbol period of the adjusted synchronization symbol is different (smaller or greater) than the common symbol period. In these cases, this method includes determining the symbol synchronization period by determining a number of symbols of the common symbol period that can be transmitted in the time elapsed between the end of the frame and the end of time. Therefore, the adjusted timing symbol can be used in combination with the set number of symbols in the common symbol period.

Embodiments of the present invention are also directed to a device that includes a network time clock circuit, a system time clock circuit and a processing circuit. The network clock circuit of this device is sensitive to a daily network time and the system time clock circuit is sensitive to an AC frequency that crosses the power distribution lines. The processing circuit is designed to determine a transmission period provided with start and end times determined using the network time clock. Furthermore, the processing circuit is configured to start transmission of a frame, which includes a θ 1 z

fi * 7 0 1 /, - 00. &lt;7 5 î -12- 201ι a multitude of symbols, in response to the start time, through the power distribution lines that carry useful energy using alternating current (AC). The processing circuit is designed to synchronize a transmission time for each symbol in the plurality of symbols with the system time clock. In response to reaching the end of the frame, the processing circuit is designed to determine the symbol length for the synchronization symbol based on the time between the end of the frame and the final time as well as the transmission times for the plurality of symbols. The processing circuit is configured to then transmit the synchronization symbol through the power distribution lines.

In accordance with various embodiments of the present invention, the power distribution lines may transport electricity from the power station or more power stations (power stations) to customers in residential or commercial complexes alike. Power stations use alternating current (AC) to transmit electricity over long distances through power distribution lines. Long distance transport can be achieved by using a relatively high voltage level. Substations located near the locations where the customers are located lower the voltage level, more precisely the high voltage transforms it into low voltage (for example, using transformers). Electricity distribution lines carry this low alternating voltage from substations to consuming devices in locations where customers are. Depending on the distribution network, the exact voltages and frequencies of alternating current may vary. For example, voltage values ​​can generally be between 100-240 V (expressed as square root mean voltage values) with two commonly used frequencies of 50 Hz and 60 Hz. In the United States, for example, a distribution network can provide customers with a voltage of 120 V and / or 240 V at a frequency of 60 Hz.

FIG. 1 is a block diagram of an example network environment 100 in which the devices representing the endpoints of consumption communicate data with the data collection units 104, in accordance with the embodiments of the invention set forth in the present description. The network environment 100 includes a service network in which a plurality of final consumption points 102a-102f (for example, communicatively coupled) are coupled with the data collection devices 104a, 104b. According to the embodiments of the present invention.

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description, the final consumption points 102 can provide data from the utility meters (measuring devices). For example, data from power meters, gas meters and water meters that are installed in the gas and water distribution networks can be provided. Moreover, while the present description refers to the general mode of consumption endpoints 102 as elements that can provide data related to utilities (for example, power) recorded from a power distribution network, they may be communicated and other types of data.

The final consumption points 102 can be implemented in such a way as to monitor and report various operating characteristics of the service network. For example, within an electricity distribution network, meters can monitor power consumption characteristics in the network. Examples of features that define network power consumption include average or total power consumption, voltage drops, and load changes, among others. In gas and water distribution networks, meters can measure similar characteristics that are related to gas and water consumption (for example, total flow and pressure).

The final consumption points 102 report the operating characteristics of the network through the communication channels. Communication channels are portions of the spectrum through which data is transmitted. The central frequency and bandwidth of each communication channel may depend on the communications system in which it is implemented. In some implementations, the communication channels for utility meters (e.g., energy meters, gas and / or water) can be transmitted using communications networks that use electricity transmission lines that allocate the available bandwidth between endpoints according to a spectrum allocation technique based on multiple access with orthogonal division of frequency (OFDMA - orthogonal frequency division multiple access) or depending on another channel allocation technique.

When the final consumption points 102 are implemented in connection with the energy meters in an electricity distribution network, the final consumption points report data that updates the information coming from the meters and which may include amounts of the total consumed power, power over a specific period of time, energy consumption corresponding to peak hours, instantaneous voltage, peak voltage, minimum voltage and

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power consumption and power management quantities (for example, charging information). Each endpoint may also transmit other types of data, such as status data (for example, operating in a normal mode of operation, in emergency power mode, or another state such as be a state of recovery following a power failure).

In some implementations, symbols (representing one or more bits representing reporting and / or status data) are transmitted through the power distribution lines over a specific symbol period. A symbol period is a period of time during which each symbol is communicated. A number of symbols is contained within a frame period, representing the time when a complete frame is transmitted, in which each frame provides synchronization for the symbols of the same data frame.

In FIG.1 the final consumption points 102a-102c and 102d-102f transmit symbols along the communication channels to the data collection devices 104a and 104b, respectively. Data collection devices 104 may include circuits (for example, may include one or more data processors) configured and arranged so as to communicate with the end points of consumption through the power distribution lines. Data collection devices 104 may also include circuits for interfacing with a command center 112. The interface with command center 112 may be implemented using a variety of different types of data communication networks that include, but are not limited to, at, a wide area network (WAN) using Ethernet protocol.

According to embodiments of the present invention, the data collection devices are installed in substations and are used to control two-way communication with both the command center 112 (for example, located at a utility office) and the end points of consumption. (for example, located in customer monitoring locations). This exchange of messages with the end points of consumption can be sent individually only to a final point of consumption or it can be broadcast simultaneously to a group of end points of consumption connected with the data collection devices 104. According to certain embodiments of the invention, the data collection devices 104 are designed in compliance with industrial specifications in order to withstand the harsh environmental conditions that are present within a substation.

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4 -12- 20 »In certain embodiments of the present invention, the device (s) 104 may receive data from several final consumption points 102 while storing the data in a local database. A data collection device may also make decisions based on the data received from the end points of consumption and transmit the data received from the end points of consumption to a command center 112. For example, in a PLC network, command center 112 may receive data indicating power consumption that is significantly higher in certain portions of the power grid than in other portions of it. Based on this data, the command center 112 may allocate additional resources to that particular portion of the energy grid (eg, the load-loading ratio) or provide data that specifies that there is an increase in energy consumption in that specific portion of the energy network. power.

According to certain embodiments of the invention, the control center 112 provides an interface that allows user devices 118 to access the data received from endpoints 102. For example, user devices can be owned by the operator providing the utilities. , by maintenance personnel and / or utility utility customers. For example, the data signaling an increase in energy consumption, described above, may be provided to a user device 118 accessible through the network operator, which may instead determine the appropriate action to be taken regarding the increase in consumption. . In addition, data signaling a size related to operating time and / or a size indicating an additional voltage request, corresponding to peak hours, may also be provided to user devices 118. Similarly, if a power outage occurs, the command center 112 may provide data to user devices 118 that can be accessed by customers to provide information about a power outage and possibly provide estimation information. duration of interruption.

The data networks 110a and 110b can each be a large area network (WAN), a local area network (LAN), the Internet, or any other communication network. The data networks 110 can be implemented in the form of wireless or wireless networks. Wired networks may include any networks with media content restrictions that include, but are not limited to, networks deployed using wires from metal wires, fiber optic materials or waveguides. Wireless networks include all space propagation networks libejȚ © rF ~ - '&gt;.

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4 -12 '2012 including, but not limited to, networks implemented using radio waveforms and optical networks through free space. In certain embodiments, the data networks 110 overlap. In some embodiments, they may represent the same data network.

For example, each network 110 can provide data, at least in part, through the Internet.

Symbols that come from a certain end point of consumption can be transmitted through any of the thousands of communication channels in a PLC system. For example, each endpoint can be assigned to a particular channel using OFDMA or any other channel allocation technique. The channel allocations for final consumption points 102a-102c, 102d-102f communicating with certain data collection devices 104a, 104b can be stored, for example, in a communication database that is accessible to a command center 112 and / or data collection devices 104a, 104b.

According to the embodiments presented herein, each data collector device 104 may be configured to communicate with thousands of endpoints 102 and there may be thousands of data collection devices 104 connected to the command center 112. For example, a single data collection device can be configured to communicate with over 100,000 devices representing endpoints of consumption and a command center can be configured to communicate with over 1,000 data collection devices. Thus, there may be millions of total final consumption points and many thousands of these final consumption points can communicate with a common data collection device through a common electricity distribution line. Accordingly, the embodiments described in the present description are directed to the coordination of communications using protocols specially designed according to time and taking into account considerations related to this aspect.

As part of the present description, there is presented a method used to coordinate the communication between the devices representing the final consumption points 102a-102f and the data collection devices 104a-104b. The coordinated communications between the devices representing the final consumption points 102a-102f and the data collection devices 104a-104b take place along the distribution lines that transport the electricity using alternating current (AC). This method includes data communication, through power distribution lines, from data collection devices 104a-104b to devices representing final consumption points 102a-102f using a protocol defined by 14 ^ -2014-00476

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a first and second synchronization. The first synchronization indicates the time when the data frames are to be transmitted and the second synchronization indicates the time when the symbols in the data frames are to be transmitted. In certain embodiments, the first synchronization may be coordinated with an externally provided time, such as the standardized time provided by a Coordinated Universal Time server 120. For example, devices that collect data 104 can get standardized time by directly accessing the UTC server 120 from Intemet. In other situations, the command center 112 can access the UTC server and then provide this standardized time to the data collection devices 104. At each data collection device 104, the method additionally generates a clock corresponding to the collector device (for example, from a local oscillator circuit) and maintains a collection network time using the collector clock as the time base. The data collection device determines the first synchronization based on the network collection time (from the level of each data collection device 104). In addition, at the level of each data collection device 104, the frequency of the alternating current, which circulates on the electricity distribution lines, can be monitored or detected. Furthermore, the method includes determining a second synchronization based on the frequency of the alternating current. The method may also include adjusting the network time of the end point of consumption, at the level of each end point of consumption 102a-102f, in response to the time indicating packets / data received from a data collection device 104a-104b.

The method used to coordinate communications may include additional steps. For example, the method may also include the calculation of time elapsed between the end of the first frame and the beginning of the second frame. The end of the first frame is determined on the basis of the second synchronization, and the beginning of the second frame is determined on the basis of the first synchronization. In these embodiments of the invention, a further step of determining the number of synchronization symbols that can be transmitted before the beginning of the second frame is also included in the step of calculating the time between the end of the first frame and the beginning of the second. the second frame. The number of synchronization symbols is determined by the transmission rate of the symbol for the first frame and by the calculated time. In certain embodiments, the network time is adjusted according to a standard time provided from the outside.

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As used here, the term metrological / standardized time denotes a clock that keeps time exactly daily. For example, the International Bureau of Measures and Weights (BIPM) is responsible for maintaining accurate time worldwide. It combines, analyzes and achieves the average of the official atomic time standards of the member countries to create a single and officially Coordinated Universal Time. Such a clock is based on a time interval that is designed based on the Earth's rotational time. Such a concept may include compensating for any differences between the (slowed) rotation of the Earth and a certain time interval. Although aspects of this description are not necessarily based on certain specific organizations that maintain such metrological time, a particular example of this may be useful in discussing various aspects of this description.

The first synchronization defines the time corresponding to the transmission of the data frames and the data symbols are transmitted in response to the detection of the alternating current phases, subsequently, in other embodiments. In other embodiments, the data symbols used in this method may be useful for coordinating communications using quadrature phase shift keying (QPSK). Embodiments of this method using QPSK or other encoding protocols (for example, amplitude shift modulation, phase differential modulation, or frequency shift modulation) may track the frequency of alternating current by periodically executing a routing service. interrupts (ISR interrupt service routine) that monitors a detected signal value of the alternating current. This ISR can be executed with a frequency large enough to allow a terminal point to decode QPSK symbols using another interrupt routine to detect the value of an AC signal.

FIG. 2 shows a block diagram of a communications coordination device for the electricity distribution lines, according to the embodiments of the invention set forth in the present description. A device 206 is configured to transmit data on the power distribution lines 216 using data from the processing circuit 212 to the transmit-receive apparatus 218. In particular embodiments of the present invention, the device 206 is a data collection device 104 which is configured to transmit to

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4 -12- 2012 devices representing final consumption points 102. Processing circuit 212 generates data encoded in symbols in which several symbols form a data frame. Each symbol represents one or more bits of data which are in turn represented by a modulation carrier signal transmitted by the transmitting - receiving apparatus 218 on the power distribution lines. For example, the transceiver 218 can transmit symbols on the energy distribution lines 216 by modulating the phase of a carrier wave. This special modulation is based on the data encoded in the symbol, determined on the basis of the data to be transmitted, and on the particular coding scheme.

Aspects of the present disclosure take into account that alternating current transmission on power distribution lines may be used to maintain synchronization between a data collection device and multiple devices representing end points of consumption. Therefore, the data collection device can be configured to use the times corresponding to the alternating current 208 as part of the second synchronization operation (the first operation is discussed below) 210. For example, the frequency / period of the symbol 222 used for the encoding of the symbols transmitted on the energy distribution lines it can be set according to the times corresponding to the alternating current. In some cases, the end points of consumption can also be configured to monitor the (local) AC signal and to use the times corresponding to the AC as a basis for the respective decoding operations. The times corresponding to the alternating current can be provided by monitoring the occurrences, such as the zero signal of the alternating current. Zero crossing is just one example being possible, and others, such as detecting a particular non-zero signal value, signal limit values ​​and / or maximum / minimum signal values.

Other aspects of the present invention acknowledge that a time reference of the system may be beneficial in coordinating communications between endpoints of consumption and data collection devices. For example, operations such as meter reading are based on daily (metrological) time (for example, it is relevant for billing and / or other reporting issues). Thus, aspects of the present description are directly directed to the data collection device being configured to use another clock source 202 (for example, a daily time clock, using a local crystal oscillator) in connection with a first synchronization operation.

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204. The first synchronization operation 204 can be used to determine the start time of the data frames 220, where the data frames contain symbols using the second synchronization operation 210. The clock source 202 can be maintained using a local oscillator ( or another synchronization source) while also being updated occasionally based on information received from a UTC server (either directly or through a command center 112).

Aspects of the present disclosure are also directly directed at compensating for the differences between the second synchronization operation 210 and the first synchronization operation 204. For example, the data collection device 206 can be configured and designed to transmit data using data frames that use at least one synchronization symbol, having a predetermined period of the symbol, to be transmitted before the start of the data frame. For example, a communication protocol may define several synchronization symbols. These synchronization symbols will be detected by a decoder and used to generate synchronization information which will be used to decode the subsequently transmitted data carrier symbols. The data carrier symbols are then transmitted. Both the synchronization symbol (s) and data carrier symbols use the second synchronization operation 210; however, the start of the data transmission is set using the first synchronization operation 204. At the end of the data frame, the collector device determines the appropriate time before the data transport portion of the next frame using the first synchronization operation 204. Based on this determination, the data collection device calculates a synchronization time in which the synchronization symbols are transmitted. The data collection device then transmits a number of synchronization symbols corresponding to the synchronization time.

Particular embodiments of the present invention are directly directed to the communication protocols for which a symbol period includes multiple signal situations that may occur on the AC line. For example, a symbol may be transmitted during a corresponding symbol period of 4 zeroes. In such a case, the data collection device determines how many synchronization symbols to transmit based on the number of zeroes that are expected to occur during the calculated synchronization duration and symbol period. Several particular examples of embodiment of the invention determine situations where the expected number of zero crossings is not uniformly distributed along ^ ·

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I

0*2014-00476

4 -12- 2012 a period of symbol. For example, a symbol period corresponding to 4 zero passes will not be evenly distributed relative to an expected number of zero passes of 17. In such a situation, there may be 4 symbols (16 zero passes) leaving one Zero out. Therefore, embodiments presented in the present description adjust the symbol period for a symbol to accommodate the additional zero crossing. This adaptation may include either the extension or the shortening of the symbol period.

Certain embodiments of the present invention allow the adjustment of the symbol period to be independent of the final consumption point configuration. Thus, the final consumption point does not have to be configured to decode a symbol that has the adjusted symbol period. However, subsequent sync symbols can be transmitted using the correct / common symbol period and can therefore be decoded by the endpoints.

FIG. 3 shows a time diagram for frames transmitted through the power distribution lines, according to the embodiments of the invention set out in the present description. Transmission period 300 includes a data portion 310 and a synchronization portion 320. As shown in FIG. 3, the beginning of the data portion 310 is synchronized according to the network time, which will correspond to a first synchronization. The particular symbols 302 contained in data portion 310 are synchronized according to the system time. In certain embodiments of the invention, the system synchronization is based on the frequency of the alternating current of the energy distribution lines (for example, obtained from the monitoring of the zero crossing). The symbol period is set according to, and varies with, the frequency of the alternating current (for example, defined as a certain number of zeroes). Each data symbol 302 can therefore be transmitted via AC as a time reference.

When the end of the data portion 310 is reached, the synchronization length 330 can be determined based on the current time and the start time for the data portion of the next data frame 308. This start time is based on network synchronization (e.g., local oscillator and metrological time). A certain number of synchronization symbols 306 is determined to be capable of being transmitted during the synchronization duration 330. The data collection device

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OU - Ο Ο 4 7 6 ί 4 -12- 2012 can also determine if an adjusted synchronization period for one of the symbols 304 could provide better synchronization.

FIG. 4 shows a time diagram for the coordinated data transmissions, according to the embodiments of the invention set out herein. In a particular embodiment of the present invention, the data collection device calculates the duration until the start of the minute of the network time clock. Thus, communications from data collection devices to endpoints are synchronized to provide a frame per minute. Other time intervals than minutes can be used. Then, the data collection device estimates how many line crossings will take to get to the beginning of the minute. Alternative embodiments of the invention may not expressly calculate the number of line crossings. For example, the timing can be based on an estimated symbol period adjusted for the AC frequency. This estimation can be made, for example, by using an average frequency of last-minute line crossings (or for another period of time). The estimated number of line crossings is then correlated with the number of line crossings per symbol (symbol period). If the result is an integer, the data collection device is configured to output the appropriate number of symbols to reach the beginning of the next minute. If the calculations lead to a number of symbols exceeding the beginning of the minute, the first symbol of the synchronization period is reduced by the corresponding number of zeroes in order to transmit a synchronization period that ends as close as possible to the beginning of the minute. Alternatively, if the calculations lead to a number of symbols ending before the beginning of the minute, an additional symbol is added, which contains the appropriate number of zeroes in order to transmit a synchronization period that ends as close as possible to the the beginning of the minute. In any case, the modified symbol may be transmitted before the unmodified symbol (or at any time possible before a minimum number of synchronization symbols used as part of the communication protocol).

According to certain embodiments, the synchronization symbols may be followed by a start bit. An endpoint that receives a series of synchronization symbols will wait for a start bit to indicate the beginning of the data carrier portion of the frame. in the diagram of FIG. 4 this start bit will be provided at the beginning of the minute - network time.

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4 -12- 20) 2 [β / \ In accordance with the embodiments of the present invention, the data collection device includes a processing circuit that is configured and designed based on software programmed instructions. These software programmed instructions may include, but are not limited to, an interrupt service routine (ISR) or a query routine that can be called / run at a frequency sufficient to be able to synchronize actions with the AC frequency. For example, the call frequency of the ISR can be 10 kHz. This frequency is not limiting and different other frequencies can be implemented depending on factors such as AC signal fidelity and processing circuit processing speed, for example, including, but not limited to, frequencies of 1 kHz or higher. . For example, the frequency can be set based on the ISR's ability to properly check alternating current zeroing situations, in one embodiment, a line crossing indicator can be set independently of the ISR whenever a line crossing is detected. The ISR then checks this indicator bit to determine the appropriate action. For example, the ISR can count the number of indicator bits detected from the previous modulation of the symbol. Once the counter reaches a set number (the transmitter symbol period), the next frame symbol can be modulated.

FIG. 5 shows a flow chart for an ISR, according to the embodiments of the invention set forth in the present description. The algorithm corresponding to this flow chart may be useful for describing certain aspects of the present description. However, the algorithm is a specific example and does not necessarily limit the scope of other embodiments discussed here. For example, a query routine (periodic or triggered by a particular event) can be used.

within block 502, ISR is introduced. In certain embodiments of the present invention, SSI may be introduced periodically, for example in response to a temporal event. In block 506, the processing circuit can determine whether a line crossing event (alternating current) has occurred since the last ISR was introduced. This can be achieved, for example, by reading, at the level of block 504, an indicator or register that is set in response to a line crossing event. A line crossing event can be a zero crossing event, or other non-zero crossing points. Alternatively, other phase-related detections may be

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4 2012

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used, such as min-max detection, to detect peaks of the AC signal.

If no line crossing event (or equivalent) has occurred, then a current value for the transmitted signal (sample) can be transmitted to a digital-to-analog converter (CDA for transmission over a distribution line). For example, the protocol communication can work by modulating one or more carrier waves. The current state of the carrier wave (for example, the current phase for a protocol using frequency shift modulation) determines the sample that is sent to the CDA converter. Block 508 is therefore a situation where there is no need for modulation of the carrier wave (for example, the next period of the symbol has not been reached). You can exit the ISR at block 510.

If an event has occurred involving the line crossing, then the line interrupt frequency counter can be increased and the line crossing indicator can be deleted, as shown in block 512. The line interrupt frequency counter keeps track of the number of line crossings that occurred throughout the current period of the symbol. Therefore, block 514 represents a check whether or not the interrupt frequency counter indicates that the next period of the symbol has been reached (for example, by comparing the interrupt frequency counter with a representative threshold value for the symbol period). As an example, the symbol period can be set to 10 line-crossing events. The frequency counter of the interrupt should then increase 10 times before the threshold value of the symbol is reached. If the current period of the symbol is not indicated as complete, then the ISR moves to block 508. If, however, the current period of the symbol is indicated as complete, then the ISR moves to block 516.

In block 516, the ISR checks whether the transmission is in a portion / period of synchronization or in a portion / period of data of the current frame. In certain embodiments, this verification may be accomplished by reading an indicator or register that is set when a synchronization period begins.

If the current period is not determined to be a synchronization period, the ISR advances to block 518. If the current period is determined as a synchronization period, then the ISR advances to block 524.

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4 -12- 2012

In block 518 the ISR checks whether or not the end of the data frame of the current frame has been reached (for example, by checking a frame counter for a threshold value). If not, then the ISR will advance to block 520 in order to provide the following data symbol. In block 520, the ISR determines the modulation for the next data symbol. For example, a frequency shift modulation scheme may involve determining a new phase for a carrier wave. The ISR will also keep track of the current location in the frame (for example, by incrementing the frame counter). Once the modulation (phase) is determined, the resulting sample is then provided the CDA at block 508.

In block 522, the ISR determines the synchronization length. This determination can be a function of the network time, the symbol period, the average alternating current frequency corresponding to the previous frame (s) and the network time corresponding to the desired start for the data portion of the next frame. FIG. 6 and future explanations based on it provide more details of examples of synchronization calculation algorithms for determining the average frequency of the alternating current.

In block 524, the ISR determines whether the current synchronization period has reached the end (for example, by checking a value of the synchronization period counter or by checking a frame indicator of the start data). If the period has not been reached, then the modulation for the next synchronization symbol (for example the actual phase) in block 526 is determined and, if necessary, a value of the symbol counter is incremented to represent that the next period of time. symbol synchronization was introduced. The resulting sample is then sent to the CDA converter at block 508.

In block 528, the ISR determined that the period of synchronization of the current ended and that the next period began. consequently, the timing indicator can be reset / set to false. The modulation for starting the data period can also be determined, for example, by determining the value for a start bit that will be recognized by the downstream endpoints. The sample corresponding to this modulation can be supplied to the CDA converter at block 508.

FIG. 6 shows a flow chart for an ISR frequency, corresponding to an alternating current transmission line, which can be used to determine the average frequency of the alternating current line, in accordance with the embodiments of the invention set forth herein. in accordance with

<img file="RO130019A2_D0026.tif" />

CX-2O14-0047⁶ »T 4 -8- 2012 J« 'From this description, the data collection device is configured to take into account the variations in time of the frequency of the alternating current in the transport line and / or the lack of synchronization between the frequency of the alternating current and the network time. . For example, the data collection device can estimate the number of events corresponding to the line crossing that will occur in the period between the end of the current data frame and the beginning of the next data frame (determined based on network time). This estimate uses the frequency of the AC voltage previously determined to estimate the future frequency of the AC. For example, the ISR frequency of the AC line is introduced in block 602 in response to the line crossing detection event (or equivalent event). In block 604, the ISR frequency of the AC line determines the length of time that has elapsed since the last line crossing event that took place. In certain embodiments, this determination can be made by accessing a high resolution timer. For example, the high resolution timer can run freely relative to alternating current synchronization and the current value can be compared to a value that corresponds to a previous line crossing event to determine elapsed time. The high resolution timer can also be reset to a valid line crossing event.

Block 606 determines whether or not a line crossing event is valid, for example, if the line crossing event does not fall within an acceptable range, this may indicate that the line crossing event was caused by noise or other unwanted interference. In such a case, the ISR frequency of the AC line may go to block 610 and not use the (invalid) zero-pass event in calculating the AC frequency. If, however, the line crossing current event falls within an acceptable time interval, the ISR frequency of the alternating current continues at block 608. In block 608, the ISR frequency of the alternating current line updates the frequency of the alternating current line using the time of the current line crossing event. This information can be used in a number of ways including, but not necessarily limited to, the calculation of the sliding mean frequency of the AC line frequency. More sophisticated averaging algorithms can also be used.

The signals and associated logic and functionality described in relation to the figures

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4 -12- 2612'

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Processor-based systems and / or logic circuits (sometimes referred to as software modules or logic modules) can be used in conjunction with programs, as described in the present invention, or may prove to be more convenient to build. a more specialized apparatus to implement the desired method. For example, according to the present disclosure, one or more methods may be implemented using wired circuits by programming a general-purpose processor, in another complete or semi-programmable logic circuit, and / or by a combination of such hardware. and a general purpose processor configured with software.

It is recognized that aspects of the description may be implemented using computer / processor based system configurations, other than those expressly described herein. The structure required for a variety of these systems and circuits is evident depending on the applications envisaged and the above description.

People with experience in the field will use different terms and techniques above to describe communications, protocols, applications, implementations, mechanisms, etc. An example of such a technique is the description of the implementation of a technique expressed in terms of an algorithm or a mathematical expression. That is, while the technique may, for example, be implemented in the form of executable code on a computer, the expression of that technique may be succinctly transmitted and communicated, more precisely, in the form of a formula, algorithm or algorithm. mathematical expressions.

Thus, it is known that a block indicates "C = A + B" as an assembly function whose implementation in hardware and / or software involves two inputs (A and B) and returns an output (C), as in - a combinatorial logic circuit. Thus, the use of mathematical formulas, algorithms or expressions as descriptive elements must be understood as having a physical embodiment in at least one hardware (such as a processor in which the techniques of the present disclosure can be implemented and implemented. in the form of an embodiment).

In certain embodiments, the machine executable instructions may be stored for execution in a manner compatible with one or more of the methods set forth in this specification. The instructions can be used to make a general purpose processor or dedicated processor running the instructions perform the steps of the methods. Alternatively, the steps can be performed by

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4 “12- 2012 hardware components that contain wired hardware logic dedicated to performing the steps or by any combination of programmed computer components and dedicated hardware components.

In some embodiments, aspects of the present description may be provided in the form of a computer program product, which may include a machine or computer read environment on which instructions may be used to program a computer (or other devices). electronic) for the purpose of carrying out a process, according to the present description. Accordingly, the computer-readable environment includes any type of computer-readable media / information medium suitable for storing electronic instructions.

The various embodiments of the invention described above are presented by way of example only and should not be interpreted with the purpose of limiting disclosure. Based on those discussed and presented above, persons skilled in the art will readily acknowledge that different modifications and changes may be made to this description without strictly respecting the examples of embodiments and the applications set forth and described herein. For example, such changes may include variants regarding synchronization mechanisms with (and / or monitoring) the frequency of the AC line frequency. Such modifications and changes do not depart from the true spirit and the scope of the present invention, set forth in the following claims.