Patent Publication Number: US-2023162298-A1

Title: Method for reconnecting a smart electricity meter and smart electricity meter implementing said method

Description:
TECHNICAL FIELD 
     The present invention relates to powerline or radio-frequency communication networks for automated meter management (AMM) systems. More particularly, at least one embodiment relates to a method for reconnecting a smart electricity meter in a powerline or radio-frequency communication network for automated metering management in the context of an electrical distribution service. 
     PRIOR ART 
     Powerline communication systems for automated metering management AMM systems have made their appearance during the past few years, in particular in the context of electrical distribution services. The G3-PLC standard specified in the ITU-T recommendation G.9903 can for example be cited. In such powerline communication networks, communications are established between electricity meters, referred to as smart electricity meters, and a concentrator node, sometimes referred to as a data concentrator or base node or coordinator, to allow in particular a remote automated reading of electrical consumption measurements made by said smart electricity meters and in general to allow remote control of the smart electricity meters. A plurality of data concentrators are then geographically deployed to distribute the load of collecting meter readings from the smart electricity meters. Each data concentrator then serves as a relay between a set of smart electricity meters and a management entity of the automated metering management AMM system that is responsible for processing the meter readings in a centralised manner. 
     For several years, communication networks have also been able to operate in hybrid powerline/radio-frequency mode so as to make it possible to increase the collecting performances. The G3-PLC standard specified in the ITU-T recommendation G.9903 as from the 2021 version, which incorporates hybrid mode, can for example be cited. 
     In the case where a data concentrator breaks down, it is known that the smart electricity meters that were attached to it attempt to connect to data concentrators located in their geographical neighbourhood. However, such a solution creates imbalances in the network, some data concentrators being able to find themselves managing the reading of electrical consumption measurements of a large number of smart electricity meters whereas other data concentrators, on the contrary, are managing the reading of electrical consumption measurements only for a very small number of smart electricity meters. 
     It is then desirable to overcome these drawbacks of the prior art. It is in particular desirable to provide a solution that makes it possible to distribute the load of collecting meter readings in a balanced manner between the various data concentrators. 
     DISCLOSURE OF THE INVENTION 
     A first embodiment relates to a method for reconnecting a smart electricity meter connected to a data concentrator, referred to as the current data concentrator, in a powerline or radio-frequency communication network for automated metering management in the context of an electrical distribution service. The method comprises the following steps implemented by said smart electricity meter:
     disconnecting from the current data concentrator in the case where said current data concentrator is posing a problem,   connecting to a neighbouring data concentrator different from said current data concentrator,   listening to the frames containing an identifier of said current data concentrator,   disconnecting from the neighbouring data concentrator and reconnecting to a data concentrator using the same identifier as the current data concentrator when at least N frames containing the identifier of said current data concentrator are received, with N an integer greater than or equal to 1.   

     The method allows a rebalancing of the load of collecting metering readings between the various data concentrators, following for example a breakdown of the current data concentrator, and allowing in particular an automatic reconnection to a replacement data concentrator using the same identifier as the broken-down data concentrator. 
     In a particular embodiment, disconnecting from the neighbouring data concentrator and reconnecting to a data concentrator using the same identifier as the current data concentrator when at least N frames containing the identifier of said current data concentrator are received comprises disconnecting from the neighbouring data concentrator and reconnecting to a data concentrator using the same identifier as the current data concentrator when at least N frames containing the identifier of said current data concentrator are received and a quality of link between said smart electricity meter and said data concentrator using the same identifier as the current data concentrator is above a predefined threshold value. 
     In a particular embodiment, the method comprises a step consisting in determining that said current data concentrator is posing a problem when said smart electricity meter has received no frame from said current data concentrator during a predefined time T0. 
     In a particular embodiment, the method comprises a step consisting in determining that said current concentrator is posing a problem when said smart electricity meter has received no frame from said current data concentrator during a predefined time T0 or the quality of exchanges of frames between said smart electricity meter and the current data concentrator is insufficient, and provided that said smart electricity meter is listening to a neighbouring data concentrator different from said current data concentrator. 
     In a variant, the method comprises a step consisting in determining that said current data concentrator is posing a problem when a time elapsed since the last reception by said smart electricity meter of a specific frame representing an activity of the current data concentrator is greater than or equal to a predefined time T0. 
     According to a particular feature, T0 is equal to 24 hours. 
     In a particular embodiment, said current data concentrator is a data concentrator for which the connection with said smart electricity meter has functioned without anomaly for a predefined time T. 
     According to a particular feature, T is equal to one week. 
     In a particular embodiment, the smart electricity meter establishes an ordered list L of data concentrators to which to potentially connect, the smart electricity meter reorganises the list L by placing the favourite data concentrator at the start of the list if the value of a counter of failures of connection to said favourite data concentrator is below a predefined threshold T7, and the smart electricity meter reorganises the list L by placing the neighbouring data concentrator from which said smart electricity meter has disconnected at the end of the list. 
     According to a particular characteristic, T7 is equal to 3 
     In a particular embodiment, connecting to a neighbouring data concentrator comprises:
     putting the identifier of the current data concentrator on a blacklist for a predefined time T1;   starting a process of connection to a data concentrator of the network to connect to a neighbouring data concentrator different from said current data concentrator.   

     According to a particular feature, T1 is equal to 24 hours. 
     At least one embodiment relates to a smart electricity meter connected to a data concentrator, referred to as the current data concentrator, in a powerline or radio-frequency communication network for automated metering management in the context of an electrical distribution service. The smart electricity meter comprises:
     means for disconnecting from the current data concentrator in the case where said current data concentrator is posing a problem;   means for connecting to a neighbouring data concentrator different from said current data concentrator;   means for listening to frames containing the identifier of said current data concentrator,   means for disconnecting from the neighbouring data concentrator and for connecting to a data concentrator using the same identifier as the current data concentrator when at least N frames are received, with N an integer greater than or equal to 1.   

     A computer program product is also described that comprises instructions for implementing the reconnection method according to any one of the preceding embodiments, when said program is executed by a processor. 
     A storage medium is also described that stores a computer program comprising instructions for implementing the reconnection method according to any one of the preceding embodiments, when said program is executed by a processor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The features of the invention mentioned above, as well as others, will emerge more clearly from the reading of the following description of an example embodiment, said description being made in relation to the accompanying drawings, among which: 
         FIG.  1    illustrates schematically an example of a communication system supporting an automated metering management AMM in the context of electrical distribution services; 
         FIG.  2    illustrates schematically an example of hardware architecture of a smart electricity meter used in the communication system of  FIG.  1   ; 
         FIG.  3    illustrates schematically a method for connecting a smart electricity meter to a data concentrator according to the prior art; 
         FIG.  4    illustrates schematically a method for connecting a smart electricity meter to a data concentrator according to a particular embodiment; 
         FIG.  5    illustrates schematically a method for connecting a smart electricity meter to a data concentrator according to a particular embodiment. 
         FIG.  6    illustrates schematically a method for managing connection of a smart electricity meter to a data concentrator according to a particular embodiment; 
         FIG.  7    illustrates schematically a method for selecting and connecting a smart electricity meter to a data concentrator in the context of the management method of  FIG.  6   ; 
         FIG.  8    illustrates schematically a method for seeking a favourite data concentrator in the context of the management method of  FIG.  6   ; 
         FIG.  9    illustrates schematically a method for detecting an alternative data concentrator in the context of the management method of  FIG.  6   ; 
         FIG.  10    illustrates schematically a method for detecting inactivity in the context of the management method of  FIG.  6   ; and 
         FIG.  11    illustrates schematically a method for evaluating a current data concentrator in the context of the management method of  FIG.  6   . 
     
    
    
     DETAILED DISCLOSURE OF EMBODIMENTS 
       FIG.  1    thus illustrates schematically an example of a communication system supporting an automated metering management AMM in the context of electrical distribution services, wherein the present invention is implemented. 
     The communication system comprises at least one powerline communication network PLCN  100 , simply referred to as PLCN network  100  hereinafter, deployed logically on an electrical supply network. The PLCN network  100  allows the establishment of an automated metering management AMM system in the context of the electrical distribution services. In a variant of the powerline communication network PLCN, the communication system may comprise a radio-frequency communication network. For example, the communication system implements a hybrid mode wherein the automated metering management AMM relies on a powerline communication network PLCN or on a radio-frequency communication network. Hereinafter, the invention is described more particularly in a context of a powerline communication network PLCN, but applies in a similar manner in a radio-frequency communication network context. 
     The communication system comprises a plurality of particular node devices, referred to as data concentrators DC 1 10 and  112 . The PLCN network  100  is intended to make it possible to connect a plurality of node devices to the data concentrators DC  110  and  112 . The node devices that the PLCN network  100  aims to connect to the data concentrators DC  110  and  112  are smart electricity meters SEM  121 ,  122 ,  123 ,  124 ,  131 ,  132 ,  133 ,  134 ,  135 ,  136 . More precisely, the smart electricity meters  121  to  124  are connected to the data concentrator  110  and the smart electricity meters  131  to  136  are connected to the data concentrator  112 . The data concentrators implement coordination functions and grant the smart electricity meters access to the network after authentication. The PLCN network  100  thus makes it possible to establish powerline communications so that the data concentrators DC  110  and  112  can in particular automatically proceed with operations of collecting electrical consumption metering readings, said metering being effected by the smart electricity meters with regard to electrical installations that said smart electricity meters are respectively responsible for monitoring. The PLCN network  100  furthermore enables the data concentrators DC 1 10 and  112  to proceed with application updating operations with smart electricity meters, and in general terms to remotely control said smart electricity meters. The powerline communications via the PLCN network  100  are for example in accordance with the G3-PLC protocol. In a variant, the powerline communications via the PLCN network  100  are in accordance with the PRIME specifications (“PoweRline Intelligent Metering Evolution”, as defined in the ITU normative document G.9904). These protocols construct a logic communication network PAN (the English acronym for “Personal Area Network”), superimposed on the physical electrical network. 
     The communication system furthermore comprises an entity SI (not shown on  FIG.  1   ) for managing the automated metering management AMM system, which is in particular responsible for processing the metering readings in a centralised manner. The management entity SI of the automated metering management AMM system takes for example the form of a server, or a set of servers, to which the data concentrators DC  110  and  112  are connected via cable or wireless communication links, for example of the GPRS (“General Packet Radio Service”), UMTS (“Universal MMobile Telecommunication System”) or LTE (“Long-Term Evolution”) type. 
     The data concentrators DC  110  and  112  perform the operations of collecting metering readings on behalf of the management entity SI with which they are identified by means of a network identifier PAN-ID (the English acronym for “Personal Area Network IDentifier”), e.g. in 16 bits, which is particular to them and which is attributed to them statically by the end user. In other words, the data concentrator DC  110  collects the metering readings from the smart electricity meters that are connected thereto (i.e. the smart electricity meters  121  and  124  of the PLCN network  100 , and then supplies said readings to the management entity SI for processing. 
     In the same way, the data concentrator DC  112  collects the metering readings from the smart electricity meters that are connected thereto (i.e. the smart electricity meters  131  to  136  of the PLCN network  100 ), and then supplies said readings to the management entity SI for processing. The data concentrators DC  110  and  112  manage any retransmission requirements in the PLCN network  100  to ensure that the operations of collecting the metering readings take place correctly. It should be noted that a smart electricity meter may be connected to a data concentrator by means of other meters then serving as relays. This is because the size of the electricity network and its characteristics do not make it possible for all the smart electricity meters to transmit a message directly to a data concentrator. It is therefore necessary to use some meters as relays. 
     In the remainder of the document, the terms “connected” and “attached” are used interchangeably. 
       FIG.  2    illustrates schematically an example of hardware architecture of a smart electricity meter  200  used in the communication system of  FIG.  1   . 
     According to the example of hardware architecture shown in  FIG.  1   , the smart electricity meter  200  then comprises, connected by a communication bus  210 : a processor or CPU (“central processing unit”)  201 ; a random access memory RAM  202 ; a read only memory ROM  203 ; a storage unit  204  such as a hard disk or such as a storage medium reader, e.g. an SD (Secure Digital) card reader; at least one communication interface  205  enabling the smart electricity meter to send information to a data concentrator or, where applicable, to receive therefrom. 
     The processor  201  is capable of executing instructions loaded in the RAM  202  from the ROM  203 , from an external memory (not shown), from a storage medium (such as an SD card), or from a communication network. When the smart electricity meter  200  is powered up, the processor  201  is capable of reading instructions in the RAM  202  and executing them. These instructions form a computer program causing the implementation, by the processor  201 , of all or some of the methods and steps described here. 
     The methods and steps described here can be implemented in software form by executing a set of instructions by a programmable machine, for example a DSP (digital signal processor) or a microcontroller, or be implemented in hardware form by a machine or a dedicated component, for example an FPGA (field-programmable gate array) or an ASIC (application-specific integrated circuit). 
     Thus the smart electricity meter  200  comprises electronic circuitry configured for implementing the methods and steps described here. 
       FIG.  3    illustrates schematically a method for connecting a smart electricity meter to a data concentrator according to the prior art. 
     In a step S 300 , the smart electricity meter seeking to connect to a data concentrator broadcasts at least one beacon frame BeaconRequest in order to discover its near environment. This beacon frame BeaconRequest indicates that it wishes to connect to a data concentrator. This beacon frame BeaconRequest is received by neighbouring smart electricity meters and data concentrators, i.e. devices in a position to successfully receive and decode the beacon requests sent. They respond thereto by in their turn sending a beacon frame BeaconResponse that comprises the PAN-ID and the short MAC address (i.e. a temporary 16-bit address (the complete MAC address making 64 bits) attributed by the DC) that were attributed to them. It should be noted that the smart electricity meters already authenticated with a data concentrator are also able to respond to the BeaconRequest. They offer their services as “agent” for relaying the authentication request to the data concentrator to which they are attached. 
     In a step S 302 , the smart electricity meter receives a response BeaconResponse from at least some of the neighbouring smart electricity meters or data concentrators that received the beacon frame BeaconRequest. It should be noted that some neighbouring smart electricity meters or data concentrators that have received the beacon frame BeaconRequest may have sent a response that never reached the smart electricity meter. 
     Thus the responses received enable the meter to know its near environment and in particular to know the neighbouring data concentrators to which it is able to connect either directly or by means of a smart electricity meter intervening as “agent”, i.e. serving as a relay between the smart electricity meter that sent the BeaconRequest and the data concentrator. 
     In a step S 304 , the smart electricity meter selects one of the neighbouring smart electricity meters or data concentrators from which it received a response. For example, the smart electricity meter selects the neighbouring smart electricity meter or data concentrator with which the quality of signal received, estimated on the BeaconResponse, is the best. 
     In a step S 306 , the smart electricity meter connects to the neighbouring data concentrator selected. This step generally comprises the authentication of the smart electricity meter by exchange of identification data between the smart electricity meter and the data concentrator, if necessary through smart electricity meters serving as relays. For example, in the case of the G3-PLC standard, the EAP-PSK authentication protocol is used. Once the smart electricity meter has been authenticated, the data concentrator gives it access to the network that it is coordinating and the smart electricity meter can then exchange data with it. 
     An example of such a connection method is for example described in the document of the G3-PLC alliance published in March 2017 and entitled “NarrowbandOFDMPLC specifications for G3-PLC networks”. 
     With reference to  FIG.  1   , considering that the data concentrator  110  breaks down at an instant t, generally at least one period tmin elapses, e.g. tmin = 24 h, and less than tmax, e.g. tmax = 5 days, before it is replaced. The durations of tmin and tmax mentioned above are given by way of indication and are configurable. Generally, after 24 h, i.e. at (t + 24 h), there are no longer any frames comprising the identifier of the data concentrator  110  that has broken down circulating in the PLCN network  100 , said frames emanating from the smart electricity meters previously connected to the data concentrator  110 . Thus, after 24 h, the smart electricity meters previously connected to the data concentrator  110  are de facto disconnected therefrom. The smart electricity meters  121  to  124  that were connected to the data concentrator  110  will then seek to connect to a neighbouring data concentrator, e.g. to the data concentrator  112 . In the prior art, the smart electricity meters  121  to  124 , once connected to the data concentrator  112 , remain connected thereto even when the data concentrator  110  is replaced by a new data concentrator. This creates imbalances in the network. On the other hand, according to the method of  FIGS.  4  and  5   , the data concentrator  112  serves as an attachment data concentrator for the smart electricity meters  121  to  124  in a transient manner, i.e. the time for which the broken-down data concentrator  110  is replaced by a new data concentrator or, if it is a case of a transient breakdown, when it begins to function correctly again. According to this embodiment, the new data concentrator is attributed the same identifier PAN-ID 110  as the data concentrator  110  that it is intended to replace. 
     Moreover, the new data concentrator is configured for broadcasting “ping” messages. In a variant, the new data concentrator is configured for broadcasting “ping” messages as long as the number of smart electricity meters that are connected to it is below a predefined threshold value, e.g. 10. These “ping” messages do not contain a payload but comprise the identifier of the new data concentrator, which is the same as the identifier PAN-ID 110  of the data concentrator  110  that it is intended to replace. The “ping” messages thus broadcast are listened to by the smart electricity meters previously connected to the data concentrator that the new DC replaces and which are at one hop from said new smart electricity meter, referred to as “1 st  hop” smart electricity meters. Thus the “1 st  hop” smart electricity meters implement the connection method described in relation to  FIG.  4    or  FIG.  5    in order to disconnect from any neighbouring DC and to connect to the new DC. By means of these “1 st  hop” smart electricity meters connected to the new DC, other smart electricity meters (previously connected to the data concentrator that the new DC replaces) will in their turn be able to listen to frames containing the PAN-ID of the old DC transmitted by said “1 st  hop” smart electricity meters, and undertake the method for connection to this new DC described in relation to  FIG.  4    or  FIG.  5   . A variant embodiment is also described below in relation to  FIG.  6    et seq, in the context of a management of connection of a smart electricity meter to a data concentrator according to a particular embodiment. 
       FIG.  4    illustrates schematically a method for connecting a smart electricity meter  122  following a problem, e.g. a breakdown, of the data concentrator  110  to which the smart electricity meter  122  is currently connected according to a particular embodiment. The method described in relation to the smart electricity meter  122  is implemented by all the smart electricity meters connected to the data concentrator  110 . 
     In a step S 400 , the smart electricity meter  122  determines whether the data concentrator  110  to which it is connected is posing a problem, e.g. is broken down. In one embodiment, the smart electricity meter  122  determines that the data concentrator  110  is posing a problem when it has not received a frame from the data concentrator  110  during a predefined time T0, e.g. T0 = 24 h (in agreement with the aforementioned time tmin). 
     In a variant embodiment, the meter  122  determines that the data concentrator  122  is posing a problem when it has not received a frame from the data concentrator  110  during a predefined time T0, e.g. T0 = 24 h, or when it notes that the quality of frame exchanges at the application level with the data concentrator to which it is connected is insufficient and that it is listening to a neighbouring data concentrator, i.e. it is listening to the frames containing the identifier PAN-ID of the neighbouring data concentrator, to which it is not connected. The quality of frame exchanges at the application level is insufficient when, for example, the success level of frame exchanges at the application level is below a predefined threshold value TH, e.g. TH = 90%. The success level of frame exchanges at the application level is equal to the level Tx of correct reception by the data concentrator  110  of the frames sent by the smart electricity meter  122 . In other words, Tx = number of frames received correctly by the data concentrator/number of frames sent by the smart electricity meter. Optionally Tx is expressed as a percentage. In the case of the DLMS (the English acronym of “Device Language Message Specification”) communication protocol, which functions by data block, it suffices for the data concentrator to request a data block from the smart electricity meter so that the latter knows that the preceding data block (or frame) was received correctly. On the other hand, if the data concentrator resumes the sequence at the very start, i.e. it requests the first data block again, whereas the sequence had not ended, a failure is detected by the smart electricity meter. The smart electricity meter can thus determine the number of frames received correctly by the data concentrator and consequently determine the level Tx. 
     In a step S 402 , the meter  122  disconnects from the data concentrator  110  to which it is connected in the case where said data concentrator  110  is posing a problem. This step consists of a disconnection of the logic links between the smart electricity meter  122  and the data concentrator  110 . 
     In a step S 406 , the smart electricity meter  122  attaches itself to a neighbouring data concentrator, e.g. the data concentrator  112 . For this purpose, the smart electricity meter  122  implements the method described with reference to  FIG.  3   . In particular it sends at least one beacon frame, selects a data concentrator, e.g. the data concentrator  112 , from the neighbouring data concentrators that responded and attaches itself to the neighbouring data concentrator selected. 
     In a step S 410 , the smart electricity meter  122  once again listens to the frames (including the “ping” messages) containing the identifier PAN-ID 110  and waits (step S 412 ) to receive at least N thereof, N being an integer greater than or equal to 1, e.g. N = 10. In a variant embodiment, the smart electricity meter  122  waits to receive at least N thereof, with an LQI (the English acronym of “Link Quality Indicator”) at least equal to LQI min , e.g. LQI min  = 64. If N frames are received then the method continues at the step S 414 , otherwise it resumes at the step S 410 . 
     In the step S 414 , the smart electricity meter  122  disconnects from the neighbouring data concentrator  112  and reconnects to the replacement data concentrator identified by the PAN-ID 110 . For this purpose it implements the method described with reference to  FIG.  3   . 
     Thus the method described makes it possible automatically to rebalance the network by avoiding data concentrators, e.g. the data concentrator  112 , having a large number of smart electricity meters that are connected thereto whereas other data concentrators, e.g. the new data concentrator replacing the data concentrator  110  that is posing a problem, has no or few smart electricity meters connected. 
       FIG.  5    illustrates schematically a method for connecting a smart electricity meter  122  to a data concentrator following a problem, e.g. a breakdown, with the data concentrator  110  to which the smart electricity meter  122  is currently connected according to another particular embodiment. The method described in relation to the smart electricity meter  122  is implemented by all the smart electricity meters connected to the data concentrator  110 . On this figure, the term DC is used for signifying data concentrator. 
     In a step S 500 , variables NB ECH and X are initialised: NB ECH = 0 and X = T2, e.g. T2 = 15 minutes. NB_ECH is a positive or zero integer that represents a number of attempts at connection to a replacement data concentrator (the identifier of which is identical to the identifier PAN-ID 110  of the data concentrator that it replaces) that have failed. T2 represents a time. 
     In a step S 502 , the smart electricity meter determines that there is a problem on the data concentrator  110  to which it has been connected without a communication anomaly since a predefined time T. For example, T is equal to 1 week. Such a data concentrator is called the favourite data concentrator or favourite DC. For each smart electricity meter, the favourite data concentrator or favourite DC therefore corresponds to the last data concentrator to which it was connected without any problem during the time T. 
     If the smart electricity meter determines that there is a problem on the favourite data concentrator  110 , the method continues to the step S 504 , otherwise it resumes at the step S 502 . 
     In a particular embodiment, the smart electricity meter  122  determines that the favourite data concentrator  110  is posing a problem when it has not received a frame from the data concentrator  110  during the predefined time T0, e.g. T0 = 24 h. In a variant embodiment, the smart electricity meter  122  determines that the favourite data concentrator  110  is posing a problem when it has not received a frame from the data concentrator  110  during a predefined time T0, e.g. T0 = 24 h or when it notes that the quality of frame exchanges at the application level with its favourite data concentrator  110  is insufficient, and provided that it is listening to a neighbouring data concentrator to which it is not connected. In other words, if the smart electricity meter  122  notes that the quality of frame exchanges at the application level with its favourite data concentrator  110  is insufficient but that it is not listening to a neighbouring data concentrator to which it is not connected, the method resumes at the step S 502 . This is because in this case it is preferable to remain connected to the favourite data concentrator  110  even if the quality of frame exchanges is insufficient rather than risking being without a neighbouring data concentrator to which to connect. 
     In a step S 504 , the smart electricity meter  122  disconnects from the favourite data concentrator  110  to which it is connected. This step consists of a disconnection of the logic links between the smart electricity meter  122  and the data concentrator  110 . 
     In a step S 506 , the smart electricity meter  122  puts the identifier PAN-ID 110  of the favourite data concentrator  110  on a blacklist for a predefined time T1, e.g. T1 :::: 24 h. In other words, during the time T1, the smart electricity meter  122  ignores the frames containing the identifier PAN-ID 110 that it receives. In other words, it stops listening to the favourite data concentrator  110 . 
     In a step S 508 , the smart electricity meter  122  starts a process of connection to a data concentrator of the PLCN network  100 , e.g. the data concentrator  112 . For this purpose, the smart electricity meter  122  implements the method described with reference to  FIG.  3   . In particular, it sends at least one beacon frame BeaconRequest, selects a data concentrator, e.g. the data concentrator  112 , from the data concentrators that responded and attaches itself to the data concentrator selected. 
     In a step S 510 , the smart electricity meter  122  checks whether the connection to a neighbouring data concentrator has functioned. If such is the case, then the method continues at the step S 518 , otherwise it continues at the step S 512 . 
     At the step S 512 , if the time T1 has elapsed, the method continues at the step S 514 , otherwise it continues at the step S 516 . 
     At the step S 514 , the smart electricity meter  122  checks whether it has succeeded in connecting to a replacement data concentrator with the same identifier PAN-ID 110  as the data concentrator that posed a problem. If it has succeeded then the method resumes at the step S 500 , the replacement data concentrator automatically becoming the new favourite DC, otherwise it continues at the step S 516 . At the step S 516 , the smart electricity meter  122  waits for a predefined time X where X is a random value between two predefined values T2 and T4, e.g. T2 = 15 minutes and T4 = 2 hours. X increases gradually at each new performance of the step S 516  until it reaches T4, in which case X remains random and between T4-30 minutes and T4 and does not increase further. At the end of the waiting the method resumes at the step S 508 . 
     At the step S 518 , the smart electricity meter  122  checks whether at least one of the following conditions is met, and it remains at the step S 518  as long as none of the conditions is met (in which case the smart electricity meter  122  remains connected to the neighbouring DC):
     COND1 (C1): NB ECH is equal to NBE, e.g. NBE = 3;   COND2 (C2): a predefined time TT has elapsed as from the moment when the smart electricity meter  122  is seen connected to the neighbouring DC in the step S 510 , e.g. TT is equal to one week;   COND3 (C3): the smart electricity meter  122  has received at least N frames comprising the identifier of the DC that posed a problem, i.e. PAN-ID 110;     COND4 (C4), which is tested last: the neighbouring DC is posing a problem (situation identical to that of the step S 502  with the neighbouring DC instead of the favourite DC, i.e. when the smart electricity meter  122  has not received a frame from the neighbouring DC to which it is connected during a predefined time T0, e.g. T0 = 24 h, or when it notes that the quality of frame exchanges at the application level with its neighbouring data concentrator is insufficient, and provided that it is listening to another neighbouring data concentrator to which it is not connected).   

     In a variant embodiment, the third condition COND3 is defined as follows: the smart electricity meter  122  has received at least N frames comprising the identifier, i.e. PAN-ID 110 , of the DC that posed a problem with an LQI at least equal to LQI min , e.g. LQI min  = 64. The LQI is a value representing the quality in terms of signal-to-noise ratio of a link between two nodes of the network. 
     If COND1 or COND2 is met the method resumes at the step S 500 , the neighbouring data concentrator becoming the new favourite DC. If COND3 is met the method continues at the step S 520 . If COND4 is met, the method continues at the step S 519 . 
     In the step S 520 , the smart electricity meter  122  disconnects from the neighbouring DC to which it was connected and starts a process of connection to a DC, referred to as replacement DC, with the same identifier PAN-ID 1   10  as the DC that posed a problem. For this purpose, the smart electricity meter  122  implements the method described with reference to  FIG.  3   . In a step S 522 , it checks whether the connection has functioned. If such is the case, the method resumes at the step S 500 , the replacement DC becoming the new favourite DC. Otherwise NB_ECH is incremented by 1 in a step S 524 . In a step S 526 , NB_ECH is compared with NBE. If NB _ ECH is equal to NBE, the method resumes at the step S 508  after having reinitialised the variable X to the value T2 in a step S 528 , otherwise it resumes at the step S 518 . 
     In a step S 519 , the smart electricity meter  122  disconnects from the neighbouring DC to which it is connected. Then the method continues at the step S 528 . 
     In the particular case where a meter is ejected, e.g. by the sending of a “Kick” message, by its favourite DC, it then attempts to connect to a data concentrator by implementing the method described with reference to  FIG.  3   . The reasons for such an ejection are varied. It may be the case, for example, of forcing the smart electricity meter to connect to a DC with a different PAN-ID, or forcing the “reset” of certain communication contexts in order, after re-registration, to return to a known initial state. Consequently, this smart electricity meter does not implement the method described with reference to  FIG.  5    except when the new DC to which it attaches itself becomes its favourite DC, i.e. at the end of a time T of connection without a problem. 
     The method described with reference to  FIG.  5    also takes into account the case where the favourite DC was in transient breakdown and has restarted again, either following a reboot (remotely or on site), or by itself without its having needed a reboot, or following the disappearance of a network disturbance that prevented a connection to this DC. 
       FIG.  6    illustrates schematically a method for managing connection of a smart electricity meter  122  to a data concentrator (DC) according to a particular embodiment. The method described in relation to the smart electricity meter  122  is implemented by all the smart electricity meters in the PLCN network  100 . In a step S 600 , the smart electricity meter  122  detects an occurrence of an event. For example, the event is a periodic triggering of the algorithm of  FIG.  6   . According to another example, the event is a disconnection of said smart electricity meter  122 . 
     In a step S 602 , the smart electricity meter  122  checks that it is connected, or attached, to a DC. If such is the case, a set of steps S 606 , S 608  and S 610  is performed; otherwise a step S 604  is performed. 
     In the step S 604 , the smart electricity meter  122  implements a selection and connection method, as detailed below in relation to  FIG.  7    in a particular embodiment, in order to select and connect (or attach) to a DC, optionally by means of another smart electricity meter. 
     In the step S 606 , the smart electricity meter  122  implements an inactivity detection method, as detailed below in relation to  FIG.  10    in a particular embodiment, in order to detect whether the DC to which said smart electricity meter  122  is connected is still active from the point of view of said smart electricity meter  122 . 
     In the step S 608 , the smart electricity meter  122  implements an alternative DC detection method, as detailed below in relation to  FIG.  9    in a particular embodiment, in order to detect whether an alternative DC exists to optionally take over from the DC to which said smart electricity meter  122  is connected. 
     In the step S 610 , the smart electricity meter  122  checks whether a favourite DC exists for said smart electricity meter  122 , that is to say whether a favourite DC has been defined for said smart electricity meter  122  (see in particular a step S 1118  described below in relation to  FIG.  11   ). If such is the case, a step S 614  is performed, otherwise a step S 612  is performed. 
     In the step S 612 , the smart electricity meter  122  implements a method for evaluating the DC to which said smart electricity meter  122  is connected, as detailed below in relation to  FIG.  11    in a particular embodiment. In order to evaluate the relevance of defining this DC as favourite DC (if such is not already the case) and if required disconnecting from this DC to reconnect to an alternative DC (if such an alternative DC exists). 
     In the step S 614 , the smart electricity meter  122  checks whether the DC to which said smart electricity meter  122  (current DC) is connected is the favourite DC of said smart electricity meter  122 . If such is the case, a step S 616  is performed; otherwise a set of steps S 618  and S 620  is performed. 
     In the step S 616 , the smart electricity meter  122  implements the method for evaluating the DC to which said smart electricity meter  122  is connected, as already mentioned with regard to the step S 612 . 
     In the step S 618 , the smart electricity meter  122  implements the method for evaluating the DC to which said smart electricity meter  122  is connected, as already mentioned with regard to the steps S 612  and S 616 . 
     In the step S 620 , the smart electricity meter  122  implements a method for seeking the favourite DC, as detailed below in relation to  FIG.  8    in a particular embodiment, in order to reconnect to the favourite DC, more particularly in the case where a replacement DC has been introduced into the PLCN network  100  to replace a DC that has posed a problem and which was the favourite DC of said smart electricity meter  122 . 
       FIG.  7    illustrates schematically a method for selecting and connecting a smart electricity meter  122  to a data concentrator (DC) in the context of the management method of  FIG.  6   . The method of  FIG.  7    starts in a step S 700 . 
     In a step S 702 , the smart electricity meter  122  awaits a potential delay. For example, the potential delay is of a random value between 0 and an upper bound. For example, the upper bound is a multiple of a value of a counter of attempts at connection to a DC each time the algorithm of  FIG.  7    is implemented. In a particular embodiment, when the step S 702  is first performed at each implementation of the algorithm of  FIG.  7   , the smart electricity meter  122  applies a zero delay. 
     In a step S 704 , the smart electricity meter  122  performs a scan in order to discover its near environment. More precisely, the smart electricity meter  122  transmits BeaconRequest beacon frames, to which said smart electricity meter or data concentrator (DC) receiving them responds. The smart electricity meter  122  is thus capable of determining which candidate DC or DCs exist for connecting to. 
     In a step S 706 , the smart electricity meter  122  checks whether at least one DC has been detected following the scan. If such is the case, a step S 708  is performed; otherwise the step S 702  is repeated, potentially forcing the application of a non-zero delay. 
     In the step S 708 , the smart electricity meter  122  performs an ordered sorting of a list L of the DCs detected (in the case where a plurality of DCs have been detected during the scan) according to a quality of communication for each DC (or PAN) detected. In a particular embodiment, the smart electricity meter  122  retains in the list L a single smart electricity meter or data concentrator PAN, typically for one having the best communication conditions (e.g. LQI). 
     In a step S 710 , the smart electricity meter  122  potentially organises the list L according to a counter of failures of connection to the favourite DC. More precisely, if the following criteria are met:
     the favourite DC is defined for said smart electricity meter  122 ;   the favourite DC is identified in the associated list L (e.g. by its associated PAN-ID identifier); and   the value of the counter of failures of connection to the favourite DC is below a predefined threshold T7 (for example T7 is equal to 3);   
 then the favourite DC is placed at the start of the list L. Thus a connection to the favourite DC will be attempted first.
     In a step S 712 , the smart electricity meter  122  potentially reorganises the list L according to information indicating from which DC said smart electricity meter  122  has disconnected last, for example as indicated in a variable DisconnectedPANId. More precisely, if the DC in question is identified in the list L (e.g. by its associated identifier PAN-ID), then the DC in question is placed at the end of the list L. Thus a connection to any other DC will be attempted before the smart electricity meter  122  has had to reconnect to the DC from which said smart electricity meter  122  has just disconnected. 
     In a step S 714 , the smart electricity meter  122  selects a DC in the list L. At each iteration of the step S 714 , the smart electricity meter  122  selects a DC in the order of the list L. 
     In a step S 716 , the smart electricity meter  122  makes an attempt at connection (or attachment) to the DC selected at the step S 714 . As already mentioned, this step generally comprises the authentication of the smart electricity meter by exchanging identification data between the smart electricity meter and the DC as required through smart electricity meters serving as relays. 
     In a step S 718 , the smart electricity meter  122  checks whether the attempt at connection of the step S 714  has taken place successfully. If such is the case, a step S 722  is performed; otherwise a step S 720  is performed. 
     In the step S 720 , the smart electricity meter  122  checks whether at least one DC remains in the list L for which no attempt at connection has been made, if such is the case, the step S 714  is repeated by selecting another DC remaining in the list L; otherwise the step S 702  is repeated, potentially by increasing the waiting time. 
     In the step S 722 , the smart electricity meter  122  checks whether the DC to which said smart electricity meter  122  has connected is the favourite DC of said smart electricity meter  122 . If such is the case, a step  726  is performed; otherwise a step S 724  is performed. 
     In the step S 724 , the smart electricity meter  122  increments by one unit the counter of failures of connection to its favourite DC. Then a step S 728  is performed, in which the algorithm of  FIG.  7    is ended. 
     In the step S 726 , the smart electricity meter  122  resets and reactivates the counter of failures of connection to its favourite DC. Then the step S 728  is performed. 
       FIG.  8    illustrates schematically a method for seeking the favourite DC in the context of the management method of  FIG.  6   . The method of  FIG.  8    starts in a step S 800 . 
     In a step S 802 , the smart electricity meter  122  determines a time elapsed since the last search with a favourite DC. 
     In a step S 804 , the smart electricity meter  122  checks whether the elapsed time in question is greater than or equal to a predefined time T8. For example, the predefined threshold time T8 is equal to 3 hours. If such is the case, a step S 806  is performed; otherwise a step S 814  is performed, wherein the method of  FIG.  8    is ended. 
     In the step S 806 , the smart electricity meter  122  checks whether a quantity of frames received from a DC other than the one to which said smart electricity meter  122  is connected (or attached), where this other DC is the favourite DC of said smart electricity meter  122 , is sufficient for reconnecting to said favourite DC. For example, the smart electricity meter  122  checks whether said quantity of frames is greater than or equal to a predefined threshold quantity QFF (e.g. QFF = 100). If such is the case, a step S 808  is performed; otherwise a step S 812  is performed. 
     In the step S 808 , the smart electricity meter  122  records information indicating from which DC said smart electricity meter  122  has last disconnected. Thus, for example, the smart electricity meter  122  records an identifier representing said DC (typically its associated identifier PAN-ID) in the variable DisconnectedPANId. Then, in a step S 810 , the smart electricity meter  122  disconnects from the DC in question, and the step S 812  is next performed. Then, by applying the algorithm of  FIG.  6   , the smart electricity meter  122  will reconnect to its favourite DC. Thus, when the favourite DC of the smart electricity meter  122  has encountered a problem and has been replaced, the smart electricity meter  122  will reconnect to the replacement DC that was introduced into the PLCN network  100 . 
     In the step S 812 , the smart electricity meter  122  resets a frame counter (the one used for determining the aforementioned quantity of frames at the step S 806 ) and reactivates it (or activates it for the very first performance of the step S 812 ). Then the algorithm in  FIG.  8    is ended in the step S 814 . 
       FIG.  9    illustrates schematically a method for seeking (or detecting) an alternative DC in the context of the management method of  FIG.  6   . The method of  FIG.  9    starts in a step S 900 . 
     In a step S 902 , the smart electricity meter  122  determines a time elapsed since the last seeking of an alternative DC. 
     In a step S 904 , the smart electricity meter  122  checks whether the elapsed time in question is greater than or equal to a predefined threshold time T9. For example, the predefined threshold time T9 is equal to 6 hours. If such is the case, a step S 906  is performed; otherwise a step S 914  is performed, in which the method of  FIG.  9    is ended. 
     In the step S 906 , the smart electricity meter  122  checks whether a quantity of frames received from a DC other than the one to which said smart electricity meter  122  is connected (or attached) is sufficient for reconnecting, if required, to this other DC (alternative DC). For example, the smart electricity meter  122  checks whether said quantity of frames if greater than or equal to a predefined threshold quantity QFA (e.g. QFA = 100). It should be noted that there may be a plurality of other DCs that meet the above condition, in which case a plurality of alternative DCs are available. If at least one other DC is thus detected, a step S 908  is performed; otherwise a step S 910  is performed. 
     In the step S 908 , the smart electricity meter  122  records that there is at least one alternative DC to which said smart electricity meter  122  has the possibility of attaching. For example, the smart electricity meter  122  records this information by means of a Boolean AlternatePANPresent with the value “TRUE”. Then a step S 912  is performed. 
     In the step S 910 , the smart electricity meter  122  records that there is not an alternative DC to which said smart electricity meter  122  has the possibility of attaching. For example, the smart electricity meter  122  records this information by means of the Boolean AlternatePANPresent with the value “FALSE”. Then a step S 912  is performed. 
     In the step S 912 , the smart electricity meter  122  resets at least one frame counter (the one or the ones used for determining the aforementioned quantity of frames at the step S 906 ) and reactivates it or them (or activates it or them for the very first performance of the step S 912 ). Then the algorithm in  FIG.  9    is ended in the step S 914 . 
       FIG.  10    illustrates schematically a method for detecting inactivity in the context of the management method of  FIG.  6   . The method of  FIG.  10    starts in a step S 1000 . In a step S 1002 , the smart electricity meter  122  determines a time elapsed since the last reception of a specific frame representing an activity of the DC to which the smart electricity meter  122  is connected (or attached). The specific frame in question is for example a frame in accordance with the DLMS communication protocol or a frame in accordance with the ICMP communication protocol (the English acronym for “Internet Control Message Protocol”). 
     In a step S 1004 , the smart electricity meter  122  checks whether the elapsed time in question is greater than or equal to a predefined threshold time T10 (equivalent to T0 in the context of  FIGS.  4  and  5   ). For example, the predefined threshold time T10 is equal to 24 hours. If such is the case, the smart electricity meter  122  considers that the DC in question is posing a problem, and a step S 1006  is performed; otherwise this means that the DC in question is still active and is not posing a problem, and a step S 1010  is performed, in which the method of  FIG.  10    is ended. 
     In the step S 1006 , the smart electricity meter  122  records information indicating from which DC said smart electricity meter  122  has last disconnected. Thus, for example, the smart electricity meter  122  records an identifier representing said DC (typically its associated identifier PAN-ID) in the variable DisconnectedPANId. Then, in a step S 1008 , the smart electricity meter  122  disconnects from the DC in question, and the method in  FIG.  10    is ended in the step S 1010 . Then, by applying the algorithm in  FIG.  6   , the smart electricity meter  122  will reconnect to an alternative DC. This case can in particular arise when the smart electricity meter  122  was connected to its favourite DC and the latter must be replaced following a problem encountered. 
     The approach described in relation to  FIG.  10    for determining that the DC in question is posing a problem can be applied in the context of the methods described above in relation to  FIGS.  4  and  5   . 
       FIG.  11    illustrates schematically a method for evaluating the DC to which the smart electricity meter  122  (current DC) is connected (or attached) in the context of the management method of  FIG.  6   . The method in  FIG.  11    starts in a step S 1100 . 
     In a step S 1102 , the smart electricity meter  122  determines a time elapsed since the last evaluation of the DC to which the smart electricity meter  122  is connected (or attached). 
     In a step S 1104 , the smart electricity meter  122  checks whether the elapsed time in question is greater than or equal to a predefined threshold time T11. For example, the predefined threshold time T11 is equal to 6 hours. If such is the case, a step S 1106  is performed; otherwise a step S 1124  is performed, in which the algorithm in  FIG.  11    is ended. 
     In the step S 1106 , the smart electricity meter  122  checks whether the quality of the data blocks received in frames (potentially relayed) coming from the DC to which the smart electricity meter  122  is connected (or attached) is insufficient. For example, the smart electricity meter  122  checks whether incomplete data blocks are received in frames (potentially relayed) coming from the DC to which the smart electricity meter  122  is connected (or attached) in a quantity greater than or equal to a predefined threshold quantity T12. For example, in the context of transfer of data blocks in accordance with the DLMS communication protocol, T12 = 6. An error rate can also be considered. If the quality of the data blocks received is insufficient, a step S 1106  is performed; otherwise a step S 1116  is performed. 
     In the step S 1108 , the smart electricity meter  122  resets a block counter (the one used, in a particular embodiment, for determining the quantity of incomplete blocks at the step S 1106 ) and reactivates it. Then a step S 1110  is performed. In the step S 1110 , the smart electricity meter  122  checks whether an alternative DC exists. For example, as already mentioned, this information can be stored in the Boolean AlternatePANPresent, with the value “TRUE” in the case of the presence of an alternative DC or with the value “FALSE” in the case of absence of an alternative DC. If an alternative DC exists, a step S 1112  is performed; otherwise a step S 1124  is performed, in which the algorithm in  FIG.  11    is ended. 
     In the step S 1112 , the smart electricity meter  122  records information indicating from which DC said smart electricity meter  122  last disconnected. Thus, for example, the smart electricity meter  122  records an identifier representing said DC (typically its associated identifier PAN-ID) in the variable DisconnectedPANId. Then, in a step S 1114 , the smart electricity meter  122  disconnects from the DC in question, and the step S 1124  is next performed. Then, in application of the algorithm of  FIG.  6   , the smart electricity meter  122  will seek to reconnect to a DC having a better quality of communication, and preferably to its favourite DC. 
     In the step S 1116 , the smart electricity meter  122  checks whether the DC to which said smart electricity meter  122  is connected (or attached) has sufficient stability to become the favourite DC of said smart electricity meter  122  (if the DC in question is not already the favourite DC of said smart electricity meter  122 ). For example, the smart electricity meter  122  checks whether a time elapsed since the last error in communication with the DC in question is greater than or equal to a predefined threshold time T13. In other words, the smart electricity meter  122  checks whether a time elapsed without communication anomaly with the DC in question is greater than or equal to the predefined threshold time T13 (equivalent to the predefined time T mentioned in relation to  FIGS.  4  and  5   ). For example, T13 is equal to 1week. If such is the case, a step S 1118  is performed; otherwise a step S 1122  is performed. 
     In a step S 1118 , the smart electricity meter  122  declares the DC to which said smart electricity meter  122  is connected (or attached) are favourite DC. Thus, for example, the smart electricity meter  122  records an identifier representing said DC (typically its associated identifier PAN-ID) in a variable UsualPANId. Then, in a step S 1120 , the smart electricity meter  122  resets and reactivates (or activates in the case of first declaration of a favourite DC for said smart electricity meter  122 ) the counter of failures of connection to its favourite DC. Then the step S 1122  is performed. 
     In the step S 1122 , the smart electricity meter  122  resets the block counter (the one used, in a particular embodiment, for determining the quantity of incomplete blocks at the step S 1106 ) and reactivates it (or activates it for the very first performance of the step S 1122 ). Then the step S 1124  is performed.