HK1247024B - Communication method within a dynamic-depth cluster of communicating electronic devices, communicating electronic device and system - Google Patents

Description

Communication method in dynamic deep clustering for electronic communication devices, electronic communication devices, and systems

Technical Field

The present invention relates to a method for joining a cluster of communicating electronic devices, the method being implemented by a processing unit of one of the electronic devices communicating in pair via a wireless communication network.

The invention furthermore relates to a system comprising a plurality of electronic communication devices implementing such a joining method.

Background Art

As a preferred but non-limiting example application, the present invention is described using an example application related to the collection of physical quantities, such as temperature, humidity, light intensity, vibration frequency, shock, etc., associated with containers of goods or cargo, or more generally, the internal and/or external environment of the container. According to this example application, the containers are stacked and/or piled on a storage site or traveling on a transport platform, such as a container ship, a freight train, or any other suitable transport platform. Each container collaborates with one of the electronic communication devices. These electronic communication devices are responsible for collecting the quantities and transmitting them via service messages to a pair of devices acting as a "cluster head," or, as the English terminology suggests, a "head end." One of the tasks of the electronic communication device acting as a cluster head, hereinafter referred to as a head end, is to implement a specified service. Such a service may, for example, involve aggregating the data collected by the communication devices and transmitting the aggregated data to a remote entity via a long-range or long-distance connection, such as a satellite connection or a wireless telephone connection. However, the present invention is not limited to this single example application. More generally, the headend is responsible for implementing a given service associated with the data collected and sent through its pairing, which can involve monitoring or alarm management, either instead of or in addition to communication with a remote entity.

There are numerous types or configurations of networks of communicating objects. Figure 1 schematically illustrates a wireless communication network N1. Regardless of the network in which it operates, each electronic communication device (also and generally designated a "node" of the network) implements a communication method, enabling it to exchange data and/or service messages with a third node or paired nodes. Thus, network N1 comprises forty communicating electronic devices, labeled in Figure 1 as: a1 to a8, b1 to b8, c1 to c8, d1 to d8, and e1 to e8.

Such networks are generally characterized as multi-hop networks or, in English, as "multi-hop networks". According to this typology, a first node, which we will call "source", formulates a service message, represented in FIG1 by a double arrow, containing data associated with (as a non-limiting example) a quantity measured by a sensor cooperating with the first node, destined for a second "recipient" node.

In contrast to the necessarily direct communication between two nodes in a single-hop network (or "single-hop network" in English), in a multi-hop network, such as network N1 in Figure 1 , communication between the first and second nodes can be direct or indirect. Thus, according to indirect communication, a message addressed to a source node can be relayed via one or more third or intermediate nodes, each of which functions to relay the message originating from the source node so that it is ultimately sent to and received by a recipient node. Such nodes form a cluster (or, in English, a cluster). As an example, cluster C1 is represented by a dashed line and a circle in Figure 1 . The path that a service message originating from a source node follows, via one or more relay nodes, from its destination to the recipient node, is generally referred to as a "route." Thus, according to Figure 1 , a message originating from node a4 and destined for node d2 is relayed successively via intermediate nodes b4 and c3.

Communication in multi-hop communication networks is typically carried out via radio. Communication is generally short-range, meaning on the order of a few to tens of meters, so that service messages are transmitted between different nodes. If the data is destined for a server or, more generally, a remote entity, a second communication mode is implemented, for example, via GSM (Global System for Mobile Communications) or GPRS (General Packet Radio Service), or even via satellite connections.

As indicated by way of example in FIG2 , a node typically and primarily consists of an electronic communication device 10 comprising a processing unit 11, for example in the form of a microcontroller, cooperating with a data memory 12 and possibly a program memory 14, which may be separate. The processing unit 11 interacts with these memories 12 and 14 via an internal communication bus (indicated in FIG2 by a single double arrow). Typically, the electronic communication device 10 includes one or more sensors 15 for measuring physical quantities associated with the environment of the device 10. Such sensors may measure ambient temperature, humidity, or the presence/absence of light. The device 10 also includes a first communication device 13 that cooperates with the processing unit 11 and ensures wireless proximity communication with any other electronic communication device 10i within communication range. It may also include a second communication device 16 of the "long-range" type, also cooperating with the processing unit 11. These second communication means enable such a device 10 to transmit data to a remote entity, such as an RS server, by means of MC messages, which are distributed via an RR network using, for example, GSM, GPRS or satellite technology. In order to operate, that is to say, in order for the processing unit 11 to implement the method resulting from the execution or interpretation by said processing unit of the instructions of the program P recorded in the program memory 14, the device 10 comprises an electrical energy source 17, for example in the form of one or more batteries. The ability of a node to communicate or simply to operate is directly related to the remaining and available energy capacity of said node. In fact, the exchanges between nodes, the processing or calculations carried out by said nodes using the data exchanged, and the possible and remote travel of the data collected in a cluster or network of electronic communication devices are also actions that consume electrical energy.

Some constructors or operators have sought to optimize the network or communication methods implemented by the nodes in a network or cluster in order to globally preserve the electrical energy capacity of the network or cluster. Generally speaking, the first approach is to distribute the energy overhead from the exchanges between nodes to the entire network or cluster's nodes. The second approach is to distribute the energy consumption from the processing performed on the collected data, such as long-distance transmission, to a majority of the nodes, thereby sharing the electrical consumption across multiple nodes. Therefore, whether the contactless communication network is configured via a single hop or multi-hop, a node can be arbitrarily designated or promoted as a "network head" node or at least as a cluster head, i.e., a head-end node. In association with Figure 1, the device acting as the head-end is represented by a circle drawn with a group of lines. This relates to node d2 for network N1. Node d2 therefore acts as the head-end of cluster C11. In this way, the energy consumed, especially the energy consumed for the long-distance transmission of the data collected in the network, is shared across multiple nodes. As a variant, the headends may be designated randomly, or more precisely may each randomly designate itself as a headend, provided that these headends possess sufficient software and/or material components for implementing the determined service.

As an example, the "LEACH" method, such as described in particular in the document "An Application-Specific Protocol Architecture for Wireless Microsensor Networks" (W. Heinzelman, A. Chandrakasan, H. Balakrishnan – IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, VOL. 1, NO. 4, October 2002), allows for the random assignment of a node in a single-hop network to become the headend. The other nodes of the cluster belonging to the headend, which we will accordingly designate as "members" or, as the English terminology suggests, "members," address their service messages to the cluster head, and therefore to the headend. In connection with FIG. 1 , each member node is represented by a circle drawn with a thin line. Thus, in network N1, headend d2 communicates directly with nodes c1 to c4, d1, d3, and d4, as well as with nodes e1 to e4. Via member c1, headend d2 communicates with member b1, which can in turn relay messages to member a1 or to destination a1. Headend d2 collects the data emitted by the different member nodes, processes it, aggregates it, and even merges it, and triggers, for example, a long-range transmission to a remote destination entity, such as the server RS described in connection with FIG. According to this known technique, once a node has assumed the role of headend, it cannot assume this role again before a certain period of time has expired. A new member node is then randomly designated as headend, thereby ensuring continuity of service. In order to enable nodes, which we designate as "free" or, in English, "loose" (indicated in conjunction with FIG. 1 by a double-lined circle), to "join" a headend and thus form a new cluster or rejoin an existing cluster, such free nodes within the radio range of a node promoted or designated as headend are configured to receive a recruiting message MH originating from the headend, typically in the form of an indiscriminate transmission (also known by the English term "broadcast") of a recruiting message MH destined for any node within the radio range of the headend. FIG. 1 illustrates, via network N1, the results of a transmission of a message MH transmitted from node d2, designated to function as headend, according to a short-range broadcast mode to nodes within communication range. Upon receiving such a recruiting message MH, a free node, such as node e2, updates its data memory, which, in cooperation with its processing unit, stores therein the coordinates or identification value of the headend, i.e., the identification of node d2 in conjunction with FIG. 1 . The previously free device e2 becomes a member of cluster Cl 1. It is therefore represented in FIG1 by a circle drawn with a thin line. Device d2, which acts as a head end, becomes the recipient of any service message MS including the data collected by device e2, which has newly become a member of cluster Cl 1, like the other member devices of the cluster. The transmission of messages MH by node d2 is limited in range. Moreover, nodes located outside the range do not receive the message MH as an intelligible message or even receive it at all. Nodes outside the range of d2, such as nodes a5 to a8 or nodes b5 to b8, continue to be free nodes, represented by circles drawn with double lines. Cluster Cl 1 only includes node d2 acting as a head end and member nodes, that is, it has accepted the recruitment of head end d2.

The LEACH teaching, when implemented within a multi-hop network, such as network N1 described in conjunction with FIG. 1 , allows for the assumption that a node becoming a member of a cluster including a node acting as a headend records in its respective data store the routing information, namely, the identification value of the node acting as the headend and at least the identification value of the node that relayed the headend's recruit message, or even, as a variant, the identification values of relays or intermediate nodes that are separate from the headend. Thus, as an example, node c2 records the identification value of headend d2, having directly received a recruit message MH from node d2. Node b2, in addition to the identification value of node d2, also records the identification value of node c2, having relayed d2's recruit message MH for node b2.

While such an approach theoretically, or at least according to a perfect application model, allows for the conservation of global energy resources of a communication network comprising a plurality of communication nodes, in practice or in reality, and particularly depending on the use or application area of such a communication network associated with the transport of containers cooperating with electronic communication devices, such a solution remains inappropriate, or at least less effective.

In fact, the following is taken as a preferred and non-limiting application example: the utilization of a wireless communication network whose nodes store, collect, and transmit metrics associated with multiple containers, such as containers of supplies or cargo. It is assumed that each container is associated with an electronic communication device that implements a communication method such as LEACH or an equivalent multi-hop method. According to this assumption, each electronic communication device associated with a container functions as a node in a wireless network, such as the network N1 described in connection with FIG. It is assumed that the communication mode between the nodes is carried out via a radio path. Besides the fact that the LEACH-type communication method implies a single-hop path, thus specifying that each node can communicate directly with the headend, the relative arrangement of the containers, for example on a ship, at a storage facility, or on any road or rail transport platform, creates an application context in which a node designated as the headend may be unable or no longer able to fulfill its task, such as transmitting aggregated data to a destination remote unit, simply due to its location in a stack of containers. Indeed, many obstacles are posed by transport platforms and/or storage spaces, resulting from the compartmentalization or partial confinement imposed by the container's receiving structure or the interactions between the containers themselves. Stacking the containers themselves can lead to degradation or even loss of the ability to transmit data over long distances on behalf of the headend. The risk is significant: data loss, slow data transmission, and the wasteful and inappropriate expenditure of energy to "activate" a cluster whose headends are unable to effectively ensure their functionality or services. This risk is even greater in situations where the random selection of successive headends manifests itself as a less-than-productive "selection." To address these inconveniences, the applicant has devised a particularly innovative and high-performance wireless communication network that operates regardless of the relative arrangement of nodes, the network's utilization or scope of application, or whether it is a single-hop or multi-hop network. Such a network optimizes the network's overall ability to ensure services based on data collected by different nodes. It primarily relies on a method for joining a cluster of communication devices based on the headend's ability to assume this role, for example, for transmitting data in a long-distance communication mode, as a non-limiting example. Each node implementing such a method can decide to act as a headend if it is capable of doing so. Conversely, any free node can decide to join or not join a cluster, depending on the headend's capabilities, advantageously designating itself as a cluster head or headend. In addition, the applicant has devised a particularly innovative and robust wireless communication network, including when the nodes comprising the network are mobile relative to one another or when the network's topology exhibits particularly fluctuating behavior. According to this innovation, any free node can, when necessary, request a joining procedure from a member of a cluster. This joining procedure can be derived from an adaptation of a network such as the one previously described and illustrated in connection with FIG1 . A joining request by a free node is represented by a double-barred arrow. In this case, it involves free node a4, previously free, requesting to join node b4, a member of cluster C11 whose headend is node d2. Node a4's becoming a member of cluster C11 is represented by an interrupted circle. Thus, although a4 is not in a position to receive a recruitment message MH originating from headend d2, it can rejoin cluster C11 upon its request. Each node implementing such a joining process can, more generally, apply to join the members of the cluster at its request and independently of the recruitment policy of the headend, and thus transmit service messages to the headend via, in particular, the member nodes that have accepted the joining process. It is thus possible to expand the formed cluster after the recruitment process, and even transform a single-hop network into a "pseudo-multihop network," or more precisely, to adapt a single-hop network, wherein the cluster of the single-hop network becomes a multi-hop structure, in which the member nodes that have accepted the joining request act as relay nodes for the nodes admitted to the recruitment process, for transmitting service messages.

Regardless of the type of network being operated, the respective capabilities of nodes implementing methods of joining a cluster and/or admitting membership in a cluster evolve over time.

While offering significant progress, this solution, like the aforementioned competing solutions, presents certain limitations or inconveniences, particularly when such a communication network is used in application scenarios where the network's topology is particularly variable. In fact, regardless of the chosen communication network, the network's routing or topology, that is, the formation or destruction of clusters, is not updated with sufficient regularity or frequency to account for the network's dynamics. With known solutions, if such updates were implemented at a high frequency, the number of recruitment messages, cluster destruction messages, or service messages would multiply, defeating the primary purpose of conserving energy consumption at network nodes.

Furthermore, the formation of clusters with significant depth (i.e., whereby members can be located at significant distances in terms of hop counts) can generate significant message traffic inherent in the relaying of, for example, recruitment messages MH or service messages MS through repeater members. Such relaying, which is repeated at high frequency, and increasingly through numerous members, can overwhelm the energy capacity of the repeater members required to collect data, formulate, and transmit the appropriate service messages to the headend. For single-hop networks, the depth is fixed at one hop. For multi-hop networks, there are no known methods for appropriately limiting the cluster depth or even dynamically adjusting it in a uniform and controlled manner.

Summary of the Invention

The present invention makes it possible to respond to all or part of the inconveniences proposed by the known solutions. By constituting a particularly innovative and high-performance wireless communication network, regardless of the relative arrangement of the nodes and regardless of the scope of utilization or application of said network, the invention makes it possible to optimize the global capacity of the network to ensure services determined on the basis of data collected by the different nodes. The main originality of the method for joining a cluster of electronic communication devices lies in the selected modality of the head end and/or in the ability given to any node to accept or adjust the functionality of its repeater members. Each node implementing the method according to the invention can decide to act as a head end by specifying the depth of the cluster it wishes to have. Each node can furthermore, for example, maintain or limit this action according to its ability to contribute its share of resources to the relaying of recruitment or service messages. The effect of such a limitation is to reduce the depth of the cluster of which the node is a member or at least to limit the downlink routes to which said node belongs.

Among the numerous advantages brought about by the present invention, it may be mentioned that it enables:

- regulating the energy expenditure at the nodes of the network in an appropriate manner, thereby extending the network's ability to render services unmatched by prior art;

- envisages a network of nodes or at least a node structure which is automatically adaptable and functional, for example during the dispatch, storage or transport of containers each associated with an electronic device according to the invention, as required by changes in the relative positioning of the nodes or by the evolution of the conditions of utilization of said nodes;

Prioritizing the robustness of services, such as data transmission over long distances, which gives each node according to the invention the opportunity to determine its role in the network.

To this end, the present invention firstly relates to a method for communication in a network comprising a plurality of electronic communication devices, said method being implemented by a processing unit of a first electronic communication device among said electronic communication devices in the network, said first electronic communication device comprising, in addition to said processing unit, a data memory, a first communication device ensuring wireless proximity communication with a third electronic communication device of the network located within communication range, said data memory and said first communication device cooperating with said processing unit, said data memory comprising a value for an identification specific to said first electronic communication device and a record for storing the current value of an identification of a second electronic communication device acting as a cluster head. Such a method comprises:

- a step for receiving, via the first communication means, an incoming message made and transmitted by an electronic communication device in the network, said incoming message encoding an identification of a second electronic communication device acting as cluster head;

- a step for decoding the incoming message and deducing therefrom the value of the identification of the second electronic communication device acting as cluster head and, where appropriate, the value of the identification of the third electronic communication device which has relayed the incoming message;

- a step for updating the record so that the record stores the value of the identification of the second device acting as cluster head inferred from the decoded recruitment message as the current value of the identification of the device acting as cluster head and, where appropriate, the record further stores the value of the identification of the third electronic communication device as an uplink route towards the second electronic communication device acting as cluster head.

In order to control the depth of the cluster, the present invention provides:

- the incoming message further encodes TTL data, said TTL data reflecting the capability of the electronic communication device receiving the incoming message to relay the incoming message;

- a step for decoding the incoming message and, moreover, deducing therefrom the value of the TTL data;

- The step for updating a record is adapted such that said record stores a current value of said TTL data previously decremented by one unit.

The present invention further provides that the communication method according to the present invention comprises:

- a step for producing a relayed recruiting message, said message comprising:

A first field encoding the current value of the identity of the device acting as cluster head recorded in the record;

a second field characterizing an upstream route towards a second electronic communication device acting as a cluster head and encoding an identification of the first electronic communication device;

A third field encoding the current value of the TTL data entered in the record;

- a step for triggering the transmission of said relayed message by the first communication means if a previous step consisting in comparing the current value of the TTL data entered in the record with a determined bottom value proves that said current value of TTL is strictly greater than said bottom data.

To advantageously verify that the second electronic communications device is well-capable of functioning as a cluster head:

- the received recruiting message may comprise data reflecting the capability of the second electronic communication device acting as cluster head to ensure a given service;

- the step of decoding said recruiting message may furthermore deduce said data representing said capabilities from said recruiting message;

The step for updating the record may furthermore consist in entering in said record the value of said data reflecting the capability of the device to act as cluster head.

According to this advantageous embodiment, a first electronic communication device can decide to rejoin the cluster of a second electronic communication device based on certain capabilities of the second electronic communication device. To this end, the step of updating the record and entering therein the current value of the identification of the electronic communication device acting as cluster head can be advantageously implemented only if the data reflecting the capabilities is greater than or equal to a determined required minimum threshold.

In order to reduce the cluster depth, the communication preparation method of the present invention may include:

- a step for receiving a relay end message formulated and transmitted by a third electronic communication device, said relay end message including an identification of said third electronic communication device;

- a step for decoding said relay end message and for deducing therefrom the value of said identification;

- a step for updating a record comprising a current value of the identification of the device acting as the cluster-head, for erasing said current value or replacing said current value by a predetermined value reflecting the absence of the identification of the device acting as the cluster-head, said updating of the record being performed only if the value of the identification inferred from the relay end message is included in the record as an upstream route towards said device acting as the cluster-head.

In order to allow a cluster member to terminate its role as a repeater and thus preserve its ability to generate and transmit service messages to a destination device acting as a cluster head, the step of comparing the current value of the TTL data entered in the record with a determined bottom value may further comprise generating a relay message based on functional parameters of an electronic communication device in favor of the capabilities of the electronic communication device in the downstream route from the first electronic communication device, and comparing the generated capabilities with a predetermined minimum functionality threshold. The step of triggering the transmission of the relayed message by the first communication device is then carried out only if the generated capabilities are strictly greater than the predetermined minimum functionality threshold.

In order to adjust the depth of a cluster caused by the reception of an incoming message encoding TTL data that is less than the TTL data of a previous incoming message, the present invention provides a first embodiment according to which the step of updating the record after decoding the incoming message may further consist in triggering, concurrently with the updating of the record, means for measuring the duration, the communication method comprising the steps of comparing the duration with a predetermined maximum waiting period and updating the record and erasing the current value of the identification of the electronic communication device acting as a cluster head or replacing it with a predetermined value reflecting the absence of the identification of the electronic communication device acting as a cluster head.

According to a second embodiment, an incoming message may include a field encoding TTL-e data indicating the maximum depth of the cluster desired by the second electronic communication device acting as a cluster head, and a field encoding DST data indicating the distance separating the electronic communication device transmitting the incoming message from the electronic communication device acting as the cluster head (d2) on the downstream route. According to this second embodiment, the step of decoding the incoming message can infer the values of the TTL-e and DST data from the incoming message. The step of updating the record can also be adapted so that the record stores the value of the TTL-e data and the DST data pre-incremented by one unit. The present invention thus provides that the communication method may further include the steps of comparing the TTL-e and DST values entered in the record and updating the record by erasing the current value of the identifier of the electronic communication device acting as the cluster head or replacing it with a predetermined value reflecting the absence of the identifier of the device acting as the cluster head.

Regardless of the embodiment of the communication method according to the invention, the first electronic communication device can dynamically determine the relevant depth of the cluster in which it wishes to act as a cluster head. To this end, the communication method according to the invention can advantageously include:

- a step for determining, based on operational parameters of the first electronic communication device, the maximum depth of the cluster in which the first electronic communication device wishes to act as cluster head;

- a step for encoding an incoming message and triggering the transmission of said message by the first communication means, said message comprising a first field encoding the identification of said first electronic communication device and a second field encoding TTL data, said TTL data being initialized to the value of the maximum depth of the generated cluster.

As a variant, such communication methods may include:

- a step for determining, from operating parameters of the first electronic communications device, the maximum depth of the cluster of which said device wishes to act as cluster head;

- a step for encoding an enrolment message and triggering the transmission of said message by the first communication device, said message comprising fields respectively encoding:

the identification of the device;

TTL data whose value is recorded in the record;

TTL-e data whose value is initialized to the value of the maximum depth of the determined cluster;

DST data whose value is initialized to a value indicating a distance where the number of hops is zero.

In order not to trigger the transmission of a recruiting message when the first electronic communication device may not be able to fully ensure the role of cluster head, the communication method according to the invention can advantageously include a step for evaluating the ability of the first electronic communication device to assume the determined service, said step consisting in estimating the operating parameters of said device and in generating data reflecting the ability of said device to ensure said determined service, and for this purpose, the step for encoding the recruiting message consists in preparing in said recruiting message a field encoding said data reflecting said ability before triggering the transmission of said message by the first communication device.

Such a method may comprise a step for comparing the data reflecting the capability with a required minimum functional threshold and, for this purpose, performing a step for triggering the transmission of an enlistment message only if the data reflecting the capability is greater than or equal to the required minimum functional threshold.

According to a second object, the present invention relates to a computer program product comprising program instructions causing the implementation of the communication method according to the invention when said program instructions:

- is previously recorded in a program memory of an electronic communication device, said electronic communication device further comprising a processing unit, first communication means ensuring wireless proximity communication with any other electronic device located within the communication range, a data memory for recording the value of an identification specific to said device and for recording the current value of the identification of the device acting as cluster head, said memory and said first communication means cooperating with said processing unit;

- is executed or interpreted by said processing unit.

According to a third aspect, the present invention relates to an electronic communication device comprising a processing unit, a data memory, a program memory, a first communication device for ensuring wireless proximity communication with any other electronic communication device located within the communication range, said memory and said first communication device cooperating with the processing unit, said data memory comprising a record of values for an identification specific to said electronic communication device and for a current value for an identification of a device acting as a cluster head. Such an electronic communication device comprises in its program memory a computer program product such as described above and according to the present invention.

According to a fourth object, the invention relates to a system comprising a plurality of electronic communication devices also according to the invention.

According to a preferred mode of application, such a system can advantageously comprise a plurality of containers for materials, solid, fluid or liquid cargo, said containers correspondingly cooperating with electronic communication devices, each of which comprises a sensor cooperating with a processing unit for measuring and collecting quantities associated with the internal and/or external environment of said container.

BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics and advantages will appear more clearly on reading the description that follows in relation to an example of implementation given as indicative and non-limiting, and on examining the accompanying figures, in which:

- FIG. 1 described previously illustrates an example of a multi-hop configuration of a wireless communication network;

- FIG. 2 , already partially described, presents the functional architecture of an electronic communication device according to the invention and an electronic communication device according to the prior art when the device is adapted for implementing a method for joining a cluster of devices communicating in pairs via a wireless communication network, said method according to the invention;

- Figures 3 and 4 respectively depict two scenarios according to which the depth of the cluster can be dynamically adjusted according to the invention;

- Figure 5 presents a functional description of such an joining method according to the invention.

DETAILED DESCRIPTION

The electronic communication device according to the present invention is similar to known devices 10 , such as the device previously described in association with FIG. 2 .

To this end, the electronic communication device according to the present invention includes a processing unit 11, which comprises one or more microcontrollers, which are responsible for, inter alia, performing data processing. The data is advantageously stored, in whole or in part, in one or more data memories 12, which are generally electrically erasable and writable. The data memories 12 may advantageously include non-erasable sections that are physically isolated or simply arranged so that access by writing or erasing is prohibited. Such access may, as a variant, require compliance with an authentication procedure. Such advantageous sections of the data memory 12, to which access is restricted by modification, allow for the storage of identification values, inter alia, specific to the electronic communication device. Advantageously, but not necessarily, the device 10 may also include one or more program memories 14 for storing one or more programs P, or more generally, one or more sets of program instructions, which are understandable by the processing unit 11. The execution or interpretation of these instructions by the processing unit results in the operation of the device 10 or the implementation of the data processing method. The device 10 also includes first communication means 13 that ensure wireless proximity communication with any other electronic device, such as device 10i, as long as the other electronic device is within communication range. Via these first communication means 13, the device 10, or more precisely its processing unit 11, can transmit and/or receive messages to or from third devices located within the communication range. Such messages can be of any nature. Among the different types of messages, we can mention, in a non-exhaustive manner, data messages MS associated with a specific service S, recruitment messages MH, and group teardown messages MR.

Some communication devices can benefit from the electromagnetic field created by the network, drawing sufficient electrical energy from it to ensure their operation, albeit only for a short period of time. However, to ensure continuous operation and/or perform processes that require more energy, the electronic communication device 10 according to the present invention may advantageously include a suitable electrical energy source 17, which powers, in particular, the processing unit 11 and any other components of the device that may require it. Such a source 17 typically consists of one or more batteries. Depending on the preferred application context, particularly related to monitoring containers, although this specific context does not limit the scope of the present invention, the electronic communication device 10 may include one or more sensors 15 that cooperate with the processing unit 11. Such sensors can measure one or more quantities associated with the internal and/or external environment of the container and generate data therefrom. By way of example, as illustrated in FIG2 , the sensors 15 can measure the temperature and/or humidity prevailing in the container, the darkness or loss of darkness in the housing to indicate an unexpected opening of the container, or even vibrations. If necessary, the one or more sensors may cooperate with a processing unit of the device via a conductor layer or probes, in particular in the case where the device 10 is placed against the outer wall of a container and it is desired to monitor the internal environment of the container with the help of the device 10. Such a device 10 may also include a clock, which is not represented in FIG2 , so that it can time the collected measurements.

Depending on the service or services that are desired to be operated with the aid of the electronic communication device according to the invention, these electronic communication devices may comprise additional and optional means. As a preferred and non-limiting example, the services may be:

- collecting data in the vicinity of a network node of an electronic communication device according to the invention, for example related to quantities measured by said node;

- Aggregating said data collected in the vicinity of a plurality of nodes and then crafting a message MC encoding the merged service data destined for a remote entity such as a server RS.

To transmit such messages MC, the device 10 advantageously includes a second long-distance communication device 16 that cooperates with the processing unit 11. Such communication can be achieved via the RR network, via GPRS or satellite, or even via any other suitable communication path. The various internal components of the electronic device cooperate with the processing unit 11, advantageously via a wired bus or by coupling. The device 10 may include a housing that protects the components, said housing advantageously including fixing means for placing the device 10 on a support for which monitoring is desired, in this case a container according to a preferred application example.

In order to implement the present invention, it is necessary to act on the operation of the processing unit, more precisely on the communication method implemented by the processing unit. Such a method will be described later in conjunction with Figure 5. The preferred adaptation mode is to prepare a program or more generally program instructions, which are arranged to implement the method when the program instructions are executed or interpreted by the processing unit. Advantageously, the program P is loaded into the program memory 14 during the assembly of the device, or after the assembly stage of the device by downloading the program into the memory 14.

The invention consists essentially in implementing an advantageously multi-hop network, for which each node consists in an electronic communication device, such as the device 10 previously described.

The nodes of such a network are generally adapted or arranged to implement methods for joining and/or granting admission to a cluster of devices. The data memory 12 comprises, in addition to the values of the identification ID specific to the electronic communication device, a record RH provided for containing the current value of the identification IDHc of the electronic communication device acting as a headend, such as the node d2 according to FIG. 1 .

When a device chooses to join a cluster where one of its nodes functions as a headend, this joining is typically exclusive. In other words, a node cannot be a member of different clusters (i.e., each with a different headend node) for the same service. This is why we talk about clusters without coverage. A node joining a cluster selects the "best" headend for the service in question. This selection can be made, for example, based on specific capabilities to ensure the service being determined.

However, a node may also be connected to multiple headends if the headends are assigned to implement different services, such as for example a first headend for long distance data transmission (service Si) and a second headend for implementing alarm management services on site (service Sj).

To this end, as in the previously presented solution LEACH, a cluster of electronic communication devices, such as cluster C11 of network N1 described in conjunction with FIG. 1 , includes a device acting as a headend, such as node d2 described in conjunction with FIG. Other devices act as members of the cluster, such as, in a non-exhaustive manner, node c2 described in conjunction with FIG. The role of the members is primarily to collect information, such as, for example, measurements of environmental quantities, convert them into data, and then encode these data in the form of service messages MS destined for a headend capable of providing a specific service. This headend recognizes these service messages MS and then implements the specified service S. For example, such a service could consist in aggregating data transmitted from multiple members to the headend via messages MS and then implementing the long-distance transmission of these aggregated, or even merged, data in the form of messages MC to a destination remote entity RS.

A service message MS addressed from a cluster member to the destination headend is structured so as to include:

- information characterizing the type of message;

- the value of the source node's (generally a member node's) identifier;

- the value of the identity of the recipient node (in this case the headend), or even the identity of a relay member node in case of a multi-hop network;

- data, e.g. about quantities measured by device sensors;

- Possibly a redundancy code, even a cipher, or any other control information enabling a node receiving such a service message MS to decode it, utilize it or relay it.

Messages MS, like any other message circulating in the network, can trigger a receipt confirmation message MACK, which is transmitted by the message recipient to the destination source node. If no MACK message is received at the end of a specified period, or "timeout" in English, a new message MS is triggered for transmission. This is repeated for a limited number of iterations, at which point the source node considers the "route" or communication with the recipient node unavailable or no longer possible. Such a source node may decide to abandon the cluster and return to free node status, or seek to join another cluster.

The joining of a free node to a node acting as a headend is similar to the joining implemented according to the LEACH solution. However, the selection modalities of the headend and the joining modalities of the free node for becoming a cluster member can be very different, as foreseen, for example, in the variant jointly proposed by the applicants. According to this variant, only nodes that can reliably guarantee the specified service can self-designate as headends. On their side, the other nodes are free to arbitrate the competition for headends and select the headend that appears to be the best candidate for implementing the service to which they contribute.

Regardless of the selected mode of the headend, a first conceptual mode of communication devices can consist in continuously maintaining them listening to radio communication frequencies to test for the presence of messages originating from the paired device. This approach can result in significant energy consumption and burden the autonomy of the entire network. A second approach, known in English as "Wake-On-Radio (WOR)", consists in putting the nodes into relative sleep for most of their respective operating time. Radio communication is particularly deactivated, as it consumes a lot of electrical energy. However, such nodes can continue to perform less energy-intensive internal processing. In a cyclical manner, such nodes are awakened to listen for possible messages from the paired device or to transmit, in particular, recruitment messages, service messages, and the like.

FIG. 5 illustrates a communication method P100 implemented by a device according to the invention, such as, by way of example, the device 10 described in conjunction with FIG. 2 .

Such a communication method results from the implementation of a first process 100 by the processing unit 11 of the device 10 in response to the reception of an incoming message MH.

As indicated in Figure 5, the recruiting message MH includes a first field MH-1 encoding the identification IDH of the device selected to function as the headend. Such a recruiting message may also include a field MH-3 encoding CH data reflecting the headend's ability to ensure the determined service S. The message may also include a field MH-7 encoding various attributes or additional data AD, where, as a non-limiting and optional example, the data characterizes the service S to which possible CH data is associated.

In the context of a multi-hop network, structure or cluster, an incoming message can be relayed by a member. When such an incoming message has since been propagated by a member (the relaying of such a message will be studied later, in particular in connection with step 106), this means that a new incoming message has been formulated and then transmitted by a repeater member. The incoming message to be relayed is marked MH' in order to distinguish it from the original incoming message MH transmitted by the head end. Such a message MH' can include a field MH-2, which encodes data Ru characterizing the upstream route, that is to say at least the identifier ID' of the transmitter of the message MH' and the repeater member. As a variant, the route Ru can include the identifiers of different repeater members upstream, which successively separate the receiver node of the message MH' from the head end node at the origin of the original incoming message MH.

To control the depth of the cluster the head end wishes to form, the present invention provides for a message MH or MH' to include a field MH-4 encoding TTL data indicating the ability (in terms of hops) of the recipient member of the message MH or MH' to relay the message and thus propagate the incoming message within the network. The formulation of an incoming message MH by a device designated as the head end, such as device 10 according to the present invention in accordance with FIG. 2 , will be discussed later in connection with process 110 of method P100. The TTL data of the message MH or MH' can advantageously be an integer value. Thus, when the head end transmits a message MH encoding a TTL value equal to one, this means that the desired maximum depth is a maximum of one hop. A TTL value equal to three means that two different members on the downstream route can successively relay the incoming message within the network. Process 100 according to the present invention thus comprises a first step 101 of receiving an incoming message MH or MH' formulated and transmitted by an electronic communications device, such as node d2 or node c3 described in connection with FIG. 1 . Process 100 further includes a step 102 for decoding the incoming message MH or MH' and deducing from it the headend identifier IDH and possibly the member repeater identifier ID'. Step 102 further involves deducing the TTL data and decrementing it by one unit. If the decoded message MH or MH' includes CH data (which indicates the headend's ability to provide a given service S), step 102 for decoding the incoming message MH or MH' deduces from it the CH data and possibly any other useful data encoded in the message.

The process 100 further comprises a step 103 for updating a record RH arranged in the data memory 12 of a device, such as the device 10 described in connection with FIG. 2 . The record RH is prepared for storing the value of the identifier IDH, which is the current value IDHc of the identifier of the device selected to function as a headend, such as the device d2 illustrated in FIG. 1 . When the incoming message MH′ comprises the field MH-2, the uplink route Ru including the identifier ID′ of the device already functioning as a repeater member is entered in the record RH. During the updating 103 of the record RH, the value of the CH data reflecting the ability of the transmitter device to ensure the service S can also be entered in the record RH. The recorded value is marked CHc and is used to reflect the current ability of the headend to ensure the service. In a network, such as the network N1 described in connection with FIG. 1 , the device 10 that has just implemented such a method P100 becomes a member of the cluster in which the transmitter of the message MH functions as a headend. This is the case, for example, for devices acting as member nodes c1 to c3, d1, d3, and e1 to e3 of cluster C11 described in connection with FIG1 . Possibly storing the head end's capabilities in the record RH enables, when necessary, a comparison of the current head end's capabilities with those of new candidates upon receipt of a new message MH or MH' from another transmitter device. The case of contention between head ends, either free or arbitrated by the member nodes, will be considered later.

The invention further provides that nodes which are henceforth members of the cluster and/or free can join a cluster of which the node which has transmitted the message MH is a member. Therefore, according to a preferred variant, step 103 of the process 100 of the communication method P100 provided for updating the record RH can only be implemented if the CH data reflecting the capabilities of the node which wishes to act as the head end are greater than or equal to a determined required minimum threshold. The process 100 therefore comprises a step 104 for comparing the data reflecting the capabilities inferred by 102 of the message RH with the minimum required threshold. Thus, the nodes 10 which are candidates for joining the cluster can be more demanding or selective than the minimum selection criterion of the head end. The minimum required threshold is advantageously recorded in the data memory 12 or even constitutes a predefined and fixed constant in the program memory 14. It can advantageously be identical for all nodes.

As mentioned previously, recruiting messages MH may be regularly transmitted by one or more communication devices located within radio communication range, such as the device 10i described in connection with Figure 2. A device 10 acting as a member of a cluster may therefore be in a position to receive and decode a recruiting message MH or MH', which device 10 is then a member of the cluster initiated by the head end.

Two situations thus arise. According to the first scenario, the device 10 has already used a recruitment message MH or MH' originating from the same device acting as a headend. The value of the identifier IDH of this headend is therefore equal to the value IDHc stored in the record RH stored in the data memory 12 of the device 10. According to the second scenario, the value of the identifier IDH derived from the message MH or MH' is different from the value IDHc. In this case, the member device is in a situation of arbitration between two third devices that can undertake the same service.

In the case where the network provision according to the present invention indicates the head end's ability to effectively assume its role in a message MH or MH', method P100 advantageously includes step 105 after step 102 of decoding the incoming message MH and before step 103 of updating the record RH containing the current IDHc value of the device identifying the cluster head. Step 105 may advantageously consist of reading the current IDHc value from the record RH at step 1051. Step 105 may then consist of comparing the current IDHc value with the IDH value of the device identifying the transmitter of the incoming message MH decoded at step 102 at step 1052. In the first scenario mentioned above, the IDHc value and the IDH value are identical (symbolized by the connection 1052-y in FIG5 ). The record RH can therefore be updated at step 103. This action, in particular, enables the updating of the CH data in the record RH. Indeed, depending on the evolving operational context of the head end, its ability to provide services may evolve. It may be degraded, for example due to reduced energy reserves. It may be improved due to the removal of the barrier that penalizes signal transmission power via the GPRS path.

Conversely, in the case where the IDH and IDHc values differ (as indicated by the symbol 1052-n in FIG. 5 ), the device capable of functioning as a headend enters into contention with the device that, in the eyes of the members, is effectively functioning as the cluster head. Preliminary step 105 of the present invention can include step 1053 for comparing the CH data reflecting the capabilities of the device transmitting the incoming message MH with the CHc data stored in the record RH and reflecting the capabilities of the device effectively functioning as the headend to undertake the same service S. According to an advantageous embodiment, if the value of the CH data derived from the new incoming message is greater than the CHc value (as indicated by the symbol 1053-y), step 103 is implemented to update the record RH. The IDHc value assumes the value of the identifier of the transmitter of the incoming message. Device 10 thus leaves the previous cluster in order to join a cluster for which the device transmitting the message MH functions as the headend. Service messages crafted by device 10 will now be addressed to the new headend. In the opposite case, if the value of the CH data inferred from the new recruiting message is less than or equal to the CHc value (the case symbolized by connection 1053-n), then step 103 is not implemented because the transmitter of the recruiting message is not as good as the actual cluster head.

In order to limit the frequency of joining different competing head-ends and thus preserve the global energy capacity of the network, especially when the CH data and CHc data reflecting the respective capabilities of undertaking the same service are very close, the present invention provides for a certain "loyalty," albeit a very relative one, that favors the device actually acting as the head-end, even if this latter device exhibits inferior performance compared to the device entering the competition. Therefore, if the values of the identifiers IDH and IDHc differ (as indicated by the symbolic connection 1052-n), step 103 of updating the record RH is only performed if there is a significant deviation (as indicated by the symbolic connection 1053-y in FIG5 ) equal to a non-zero predetermined constant in favor of the device transmitting the incoming message. Step 1053 can thus be adapted so that the record RH is updated 103 only if the CH data reflecting the capabilities of the device transmitting the incoming message MH is greater than or equal to the data stored in the record RH plus the said deviation.

To enable relaying of recruiting messages MH beyond the transmission range of the device designated as headend, the present invention's provisioning method P100 may include a step 106, following step 103 for updating the record RH of the device implementing method P100. This additional step 106 consists in encoding a recruiting message MH', which includes, in field MH-1, the identification IDH of the device whose IDHc value is entered in the record RH, and transmitting it via communication means 13. Advantageously, if CHc data indicating the device's ability to provide a specified service S are entered in RH, such a message also encodes data indicating this capability CH in field MH-3. The message MH' generated by 106 also encodes (field MH-2, Ru) the identification ID of the device implementing method P100 and acting as a member of the repeater cluster originating from the recruiting message MH from the device acting as headend. Before the possible implementation of such a step 106 , the process 100 comprises a step 109 aimed at verifying that the device implementing the method P100 is capable of relaying the message MH or MH′ previously decoded by 102 .

Such a step 109 involves comparing the current value of the TTL data with a determined bottom value, such as zero. The current value of the TTL corresponds to the MH-4 field of the message MH or MH', advantageously decoded and decremented in advance at step 102. If the current value of the TTL is strictly greater than the bottom value (the situation represented by connection 109y in FIG. 5 ), the incoming message can be relayed. The previously described step 106 can then be implemented. In the opposite case (the situation represented by connection 109n in FIG. 5 ), step 106 is not implemented, and the incoming message is therefore not relayed by the device.

In order to adjust the depth of the cluster caused by the reception of a message MH or MH' encoding TTL data that is smaller than the TTL data of the previous incoming message, the present invention provides for a number of embodiments.

A first embodiment consists in comparing, together with the processing implemented by 109, the duration of which the starting point coincides with the updating of the record RH at step 103 with a predetermined maximum waiting period during which no other recruitment message is received. Such a duration can be measured, for example, by triggering a timer or initializing a counter that is incremented at each predetermined unit of time. If the duration is greater than or equal to the predetermined maximum waiting period, the invention prepares the device for a situation in which it is no longer in a position to transmit service messages to the current head-end, given its silence. The device then implements step 107, which consists in restoring the free node state. Such a step consists in, in particular, erasing the data associated with the current old head-end in the record RH.

Figures 1 and 4 illustrate this first embodiment. In conjunction with Figure 1 , the first recruiting message MH transmitted from node d2 includes an initial TTL value of three. This original message MH is therefore relayed in the form of a message MH' by member nodes at most two hops away from headend d2. Nodes a1 to a4, located three hops away from headend d2, have been able to join cluster Cl1 thanks to the actions of relay members b1 to b4, respectively. Figure 4 illustrates the situation in the same network N1 after the situation illustrated in Figure 1 . This situation results from the new transmission of the message MH by node d2, which now encodes a TTL value of two. According to the first embodiment of the present invention, the recruiting message MH can only be relayed in the form of a message MH' by nodes at most one hop away from headend d2. Nodes a1 to a4, previously members of cluster Cl1, which no longer receive recruiting messages MH' from nodes b1 to b4 during a predetermined maximum waiting period, resume free node status. A new cluster Cl3, in which node d2 acts as the headend, is created, replacing cluster Cl1.

As a variant or supplement, the present invention provides a second embodiment, which encodes a message MF indicating the end of message relaying and then transmits it to a device within radio communication range. This message MF is intended for nodes belonging to a downstream route. Process 130 of method P100 according to the present invention will be discussed later in conjunction with Figures 3 and 5 . According to this process, a member utilizes this message MF to restore free node status. This message MF includes the identifier of the transmitter device (denoted by IDF) and information identifying the message MF as a relay end message. Process 100 thus includes step 107 for encoding and triggering the transmission of this message MF, advantageously in a broadcast-type mode via the device's communication device 13, under the control of processing unit 11 implementing method P100. This message MF is represented in Figure 3 by a double-bar arrow. In this example, member c3 transmits this message to nodes within communication range, particularly to nodes b3 and b4, which are destinations of c3's downstream route. Cluster C11, illustrated in Figure 1, is thus created, replacing cluster C12.

Thus, in accordance with the first and second embodiments described previously, the present invention provides a first mode for limiting the depth of a cluster by regulating the propagation of such recruit messages. Furthermore, it can be observed that this regulation is fully dynamic. Indeed, as already mentioned in connection with Figures 3 and 4 , the head end can transmit a new recruit message with a smaller TTL data if it wishes to reduce the depth of the cluster of which it is the cluster head. Conversely, it can transmit a new recruit message with an increased TTL data in order to increase the depth. This mode will be discussed later in connection with process 110 of communication method P100 according to the present invention.

The present invention provides for a second mode aimed at regulating cluster depth. According to this second mode, a node implementing method P100 according to the present invention does not perform the temporal comparison with respect to the maximum waiting duration previously provided in step 109. To avoid the repeated management of the transmission of recruiting messages and thus conserve the energy consumption inherent in the utilization of such messages MH or MH' by the network, the present invention provides for recruiting messages MH or MH' to include a first supplementary field MH-5 encoding TTL-e data that explicitly indicates the maximum depth desired by the transmitter head-end. This data advantageously contains an integer value. Thus, a TTL-e value equal to one means that the head-end does not wish to propagate (or relay) the recruiting message. TTL-e therefore describes the maximum distance, in terms of hops, for a node to attempt to become a member of a cluster. In other words, a TTL-e value incremented by one unit describes the maximum number of relays permitted by one or more member repeaters on the same downstream route. The present invention provides for the inclusion of a second additional field MH-6 in the original incoming message MH and/or the relayed incoming message MH', as a supplement to field MH-5. This field encodes DST data representing the distance, in number of hops, separating the transmitter of the incoming message MH or MH' from the headend that issued the original incoming message MH on the downstream route. Thus, according to this variant, if the message MH is relayed once, the DST value of the information in the relayed message MH' is "1." If the incoming message is relayed three times, the DST value of the information in the incoming message relayed by the most distant member is "3." For this purpose, the process 100 of the communication method P100 according to the present invention can advantageously be adapted to the previously described step 102, consisting in deducing the TTL-e data and the DST value from the decoded message MH or MH'. Likewise, the previously described step 103 of updating the record RH associated with the current headend and located in the data memory 12 of the device that has received the incoming message MH or MH′ can advantageously include in addition the entry in said record RH of the values of the DST data and the TTL-e data, pre-incremented by one unit. Thus, thanks to the contents of the record RH, each device of the network knows the distance in hops that separates it from the headend on a given upstream route Ru.

To adjust the depth of the cluster initiated by the headend, step 109 of process 100 of communication method P100 according to the present invention, as in the previous mode, involves comparing the current value of the TTL data with a predetermined bottom value, such as zero. The current value of the TTL corresponds to field MH-4 of message MH or MH', which was advantageously previously decoded and decremented in step 102. If the current value of the TTL is strictly greater than the bottom value (as indicated by connection 109y in FIG5 ), the incoming message can be relayed. Step 106, previously described, can be performed. In the opposite case (as indicated by connection 109n in FIG5 ), step 106 is not performed, and the incoming message is not relayed by the device. Step 109 now involves comparing the corresponding values of the TTL-e data and the DST data recorded in record RH. If the value of the DST data is greater than the value of the TTL-e data, this means that the device is no longer in a position to transmit service messages to the current headend because it is too far away from the headend in terms of hops relative to its desired maximum depth. This situation corresponds to a reduction in the depth of the cluster initiated by the current head end. Process 100 also consists in triggering the previously described step 107, which consists in restoring the free node state. The data associated with the old current head end in the record RH are thus erased. Step 107 can also consist in encoding a message MF and then triggering its transmission, which is advantageously carried out in a broadcast-type mode by the communication means 13 of the device under the stimulation of the processing unit 11 implementing the method P100. Such a situation is also described by Figure 3, according to which the node c3 transmits a relay end message MF. The actions performed by the electronic communication device according to the invention, which is self-designated as a cluster head end, will now be described. To this end, the communication method P100 according to the invention includes a process 110. This process 110 can advantageously, but not necessarily, include a first evaluation step 111 for the device 10 to ensure the ability of the determined service S to be self-designated or self-elected as a cluster head or head end when necessary. Such a step 111 may first involve evaluating one or more operating parameters of the device 10 at 1111 to test its ability to properly provide the service. As a preferred example, assume that the service involves aggregating data collected and inferred from service messages MS, combining this data, encoding a message MC, and transmitting this message MC via long-distance communication device 16 to a destination remote server, whose task is to track containers cooperating with the communication device. To be able to provide this service, the device must obviously include an adapted communication device, such as device 16. Furthermore, such communications, for example of the GPRS type, utilize a significant amount of electrical energy, even simply to initiate a connection. Therefore, it is essential that the device acting as the headend possess sufficient energy reserves to support such a load. Furthermore, it is also preferred that the signal transmission power via the GPRS channel be optimal. In fact, weak transmission power results in slowness, thus increasing transmission duration and significantly consuming electrical energy, or even in the event of failure, requiring subsequent new transmission attempts, or simply losing the message MC.

Step 1111 may also consist of a self-test or self-assessment step for the device, for example, regarding the level of battery 17 or even the power of signal transmission via GPRS. Step 1111 may also allow for the evaluation of other functional parameters of the device, such as, for example, the number of transmitted MC messages. To this end, a transmission counter for MC messages may be implemented by processing unit 11, and the value of the counter may be recorded in data memory 12. Estimation of the load of device 10 acting as headend may thus consist of reading this counter from data memory 12.

Process 110 advantageously includes a step 1112 for generating CH data reflecting the ability of the device 10 to ensure the determined service S. For example, the generation of such CH data by the processing unit may consist in evaluating a predefined equation or function that generates a metric that integrates the estimated parameters, which are weighted accordingly, if necessary, to prioritize the parameters relative to one another. For example, the estimation of the GPRS transmission power may consist in calculating the ratio corresponding to the estimated transmission power of the test signal divided by a constant describing the typical maximum power (that is, during optimal transmission conditions).

In association with the battery level or more generally with the energy source 17 of the device, step 1112 may force the processing unit to calculate a ratio corresponding to the estimated available energy relative to the energy of the full load.

More generally, such a metric CH characterizing the ability of a device to function as a cluster head may be calculated in a non-limiting manner by evaluating an equation such as:

For it, i is an integer greater than or equal to 1, K1, K2, ..., Ki constitute weights, different if necessary, are calculation functions that may be different, for example the evolution of the ratio, and are functional parameters of the device, which as non-limiting examples are the electrical energy level of the source 17, the long-distance transmission power, the size of the memory available for recording data, computing power, etc.

The CH data can thus be similar to real values. They can also be complex, that is to say structured data, comprising every functional parameter of the device or, instead of one of the functional parameters, a determined function of one of the functional parameters.

At 1112, CH data may be generated. The method according to the present invention includes step 112 for comparing the CH data with a required minimum functional threshold value. In the case where the CH data is structured, this is also true for the threshold value. Comparison 112 can then also consist of an independent comparison of the functional parameter with a specific required minimum functional threshold value, to which combinational logic (of the AND, OR, etc. type) is applied.

If step 112 confirms that the CH data is greater than or equal to the required minimum functional threshold (connection labeled 112-y in FIG. 3 ), method P100 advantageously includes step 113 for encoding and transmitting a recruiting message MH. Prior to such transmission, the present invention provides for step 112 for determining the maximum depth of the cluster for which the device wishes to act as headend. This determination, like the capability CH generated in step 1112, can be derived from a relationship that takes into account one or more functional parameters of the device, such as, for example, i is an integer greater than or equal to 1, Q1, Q2, ..., Qi, which may be different if necessary, and may be different calculation functions, such as the evolution of a ratio, and are functional parameters of the device. Alternatively, the value of the depth Dp can be predetermined and stored in device 12 or generated from a parameterization. However, as with nodes in a LEACH-type network, a device implementing communication method P100 according to the present invention can, in violation of steps 111 and 112, self-designate, even automatically or arbitrarily, as a headend independently of its ability to effectively secure this role. However, in contrast to the prior art, the head-end according to the invention controls the depth of the clusters it initiates via data Dp.

As previously discussed in connection with the non-limiting example illustrated in FIG5 and process 100, the recruitment message MH encoded via 113 includes a first field MH-1 encoding the identification of the device, which we will label IDH, as the identification of the device selected to function as the headend. It may also include a field MH-3 encoding CH data reflecting the device's ability to ensure the determined service S, if such capability has been generated via 1112. The message MH may also include a field MH-7 encoding various attributes or additional data AD, including, as a non-limiting and optional example, data characterizing the service S to which the possible CH data is associated.

To control the depth Dp of the cluster the head end wishes to form, such a message MH includes, via field MH-4, TTL data indicating the ability of the recipient member of the incoming message to relay the incoming message and, therefore, to propagate the incoming message in the network in terms of hops. As previously mentioned in connection with process 100 described as a non-limiting example in FIG5 , such TTL data can advantageously be an integer value. Thus, when the head end transmits a message MH encoding a TTL value equal to one, this means that the desired maximum depth is a maximum of one hop. A TTL value of three means that two different members on the downstream route can successively relay the incoming message.

According to the first mode described in connection with process 100, the TTL value encoded in field MH-4 at step 113 is initialized to the value Dp. The original message MH generated at step 113 is disseminated, for example, "broadcasted," by the first communication means 13 of the device under the action of the processing unit 11 implementing method P100. Any communication device within communication range, such as device 10i depicted in FIG. 2 , can receive the message MH.

To comply with the predetermined maximum waiting period tested by 109, process 110 is iteratively implemented with a periodicity less than the predetermined maximum waiting period. When process 100 advantageously includes step 111 for estimating the capability to ensure a given service S, the capability CH can be modified, encoded, and then transmitted by 113. It can be increased to reflect a better capability or reduced in the opposite case. If comparison 112 proves at 112 that the functional parameters of the device do not meet the functional minimum, no recruitment message MH is transmitted. Therefore, any electronic device that cannot ensure a given service, even if it theoretically possesses the material or logical means for achieving this, cannot be designated as a headend or form a cluster of low-amplitude or low-depth communication devices. The cluster depth Dp, which can be modified, increased or decreased as previously mentioned, is virtually the same. The TTL data encoded in field MH-4 of each original message MH transmitted by 113 can therefore be initialized to different values from one iteration of process 110 to another. As mentioned above in connection with process 100 , the information TTL of the various messages MH acts as a regulator for the maximum depth of the cluster and intervenes by virtue of the consequences of the energy consumption of the network caused by the processing of messages exchanged in the network.

Process 110 may include step 114, optionally coupled to step 112, for comparing the CH data generated in step 1112 with a functional minimum value, which indicates insufficient capability to ensure the service. Such a minimum threshold value may be predetermined and recorded (as with the threshold value used in step 112) in data memory 12. Step 114, and, if necessary, the resulting step 115, may advantageously follow the transmission 113 of the recruitment message MH. If comparison 114 confirms (connection 114-y in FIG. 5 ) that the device can no longer ensure the service S, process 110 of communication method P100 according to the present invention may advantageously include step 115 for encoding and transmitting a cluster removal message MR, which is advantageously broadcast. This transmission of message MR may be accomplished by the device's communication device 13 under the control of processing unit 11 implementing communication method P100. Like recruitment message MH, the cluster removal message MR, transmitted by a device that previously functioned as a headend but is no longer in a position to effectively ensure the determined service S, includes the device's identification, designated as an IDR. It may also include CH data indicating the ability to guarantee service, or in this case, the inability to guarantee service. Alternatively, such a message MR may simply be associated with the transmitter device's identification, which identifies the message MR as a cluster teardown message. Such a message MR may also consist of a recruitment message MH including a TTL data equal to zero. This step 115 can advantageously be triggered only if the transmitter device previously functioned as a headend, so as to prevent the unnecessary issuance of inappropriate cluster teardown messages and prevent any unauthorized use of such messages by receiving nodes. To enable the device according to the present invention to detect that it previously served as a headend, the device's processing unit 11 may, for example, record in the data memory 12 the value Dp reflected in the MH-4 (TTL data) field of the last message MH transmitted via 113. This recording occurs concurrently with the triggering of the transmission of the message MH. The non-zero value of the value Dp recorded in the data memory 12 indicates that the device functioned as a headend during the previous iteration of process 110. During the encoding and transmission of the cluster teardown message at step 115, such a value is advantageously reinitialized to zero, or alternatively to any other predetermined value representing a zero cluster depth. Alternatively or additionally, processing unit 11 may utilize a counter for the transmission of messages MC, which, as previously mentioned, is recorded in data memory 12. During comparison 114, a value of the counter greater than its initial value indicates that the device was functioning as a headend. Upon completion of the transmission of message MR, the counter may be reset to its initial value. However, any other action may be performed by processing unit 11 to verify the implementation of step 115, instead of utilizing the transmission counter of message MC. As a non-limiting example, such an action may result from the reception by a device functioning as a headend of an incoming message originating from a third device, which itself also functions as a headend and for which the data reflecting its ability to provide the same service is greater than that of the device itself. In this case, processing unit 11 of the device implementing method P100 triggers step 115, thereby being withdrawn in the face of a superior comparison. According to this latter variant, the present invention provides for limiting the number of messages MR that are transmitted to break up a cluster. This is a direct consequence of the particularly dynamic and oscillatory evolution of a node's ability to function as a headend, which leads to very persistent competition among numerous headends. Such a situation might be encountered, for example, during rail transport of multiple containers, each of which is associated with a communication device according to the present invention and for which the service determined consists of regularly transmitting information associated with the container's contents via GPRS. The ability of a headend to transmit over long distances can be highly variable. To address this difficulty, the present invention provides for integrating a "contention factor" into the implementation of step 114, e.g., a positive real number greater than 1, whose value can be recorded in the memory 12 of the various nodes. Consequently, a headend receiving a recruiting message MH originating from a third node does not strictly compare, at step 114, the CH data reflecting the respective capabilities to ensure the same service. Step 114 involves comparing the CH data derived from the recruiting message MH, multiplied by the competition factor. Therefore, if the factor is greater than 1, e.g., 1.25, the node implementing step 114 is penalized relative to its competitors by utilizing the factor. Thus, even though the CH data of the node in question represent better capabilities than those of the headend that has issued the message MH, the application of the contention factor potentially improves the capabilities of the competitor. In this case, the node implements step 115, transmits a message MR to dismantle the cluster, and rejoins the competitor's cluster as a member. Such a solution makes it possible to limit the creation and/or dismantling of clusters that are too numerous and burden the network's energy capacity. It also makes it possible to limit the number of nodes that can act as headends simultaneously. In fact, depending on the envisaged service S (which, for example, includes long-distance transmission), an excessive number of nodes acting in concert as headends could, for example, draw too much from the network's energy reserves. The contention factor can therefore be considered a dynamic adjustment parameter for the number of headends and the adaptability of the network to its environment.

To implement the second mode of regulation previously mentioned in connection with process 100 described in conjunction with FIG. 5 , the message encoded via 113 includes a first supplemental field MH-5 encoding TTL-e data that explicitly indicates the maximum cluster depth desired by the headend transmitting the incoming message. Such TTL-e data advantageously represents an integer value. Thus, a TTL-e value equal to one means that the headend does not wish to propagate (or relay) the incoming message. Values strictly greater than one describe the number of relays permitted by one or more repeater members on the same downstream route, by increasing the number of hops by one. The present invention provides for the inclusion of a second additional field MH-6 in the original incoming message MH as a supplement to field MH-5. This field encodes DST data indicating the distance, in hops, separating the transmitter of the incoming message MH or MH′ from the headend on the downstream route from the headend that issued the original incoming message MH. Therefore, according to this variant, if message MH is relayed once, the DST value of the information in the relayed message MH' is "1." If the recruiting message is relayed three times, the DST value in the recruiting message relayed by the farthest member takes on the value "3." To implement this second mode, step 113 initializes the TTL-e value encoded in field MH-5 to the value Dp generated by 112. The TTL data is initialized using the value entered in data memory 12. It corresponds to the maximum depth of the cluster generated before the transmission of the recruiting message triggered during the previous iteration of process 110. The TTL value is thus encoded in field MH-4 of the message MH to be transmitted by the device. As for the DST data encoded in field MH-6 of the message MH, it is initialized to zero or any other predetermined value indicating zero distance. In effect, the headend is zero hops away from itself. At the conclusion of the triggering of the transmission of message MH, the current value of Dp is updated in data memory 12. As previously mentioned in connection with process 100 described in FIG5 , the coexistence of fields MH-4, MH-5, and MH-6 in message MH makes it possible to propagate the recruitment message within the cluster by means of the relayed message MH′. Thus, members receiving such a message MH or MH′ can verify that they are capable of relaying, in particular, service messages or of recovering free node status. The present invention thus makes it possible to easily adjust the depth of a cluster under the instigation of its headend. It is thus possible to maintain, increase, or reduce the depth through a combination of TTL data, TTL-e, and DST.

The present invention also enables cluster members to adjust their possible functionality as repeaters based on their energy or communication capacity. Fully adhering to the headend's rules, by implementing processes 100 and 110 according to the first or second modalities, a member's relay functionality can be limited to benefit other member nodes belonging to the downstream route or nodes permitted to join. To this end, the present invention's preliminary step 109 can generate a relay service message or other capability CR for benefiting third devices belonging to the downstream route, similar to the possible steps 111 and 112 for generating the capability CH and cluster depth Dp, respectively, from the designated headend. Such a capability CR can advantageously be calculated, for example, where i is an integer greater than or equal to 1, R1, R2, ..., Ri constitute weights, which may be different, and are possibly different calculation functions, such as the evolution of ratios, and are functional parameters of the member devices. Based on the contents of the CR and by comparison with one or more predetermined minimum functionality thresholds, for example, recorded in data storage 12, steps 106 or 107 are implemented. Thus, upon receiving a message MH or MH' from the headend of the cluster to which it belongs, a repeater member, while not automatically propagating the incoming message, will be instructed by the elements decoded by 102 (TTL, even TTL-e and DST). Preference is given to the previously mentioned first or second modalities, and the present invention ensures continuity of unequal services by automatically influencing the roles associated with different nodes of a network of electronic communication devices. The robustness of such a network according to the present invention is thereby multiplied.

To transmit service messages originating from member nodes or nodes admitted to membership, method P100 further includes a process 120, which is triggered, as non-limiting examples, upon receipt of a service message transmitted by a third device or in response to environmental measurements taken by the device. In the record RH recorded in data storage 12, the identification pair of the cluster head (headend) and a cluster member device constitutes the routing information necessary for the headend to relay the service message MS to its destination. In practice, such process 120 includes a step 123 for transmitting the service message MS to the destination device acting as the headend for the determined service S. Such a step 123 is performed after a prior step, for example, for collecting measurements from sensors 15 related to the temperature prevailing in the container against which the device 10 implementing communication method P100 is positioned. Obviously, such a step 123 also depends on the presence of a record RH (step 122 in FIG. 5 ), which includes the IDHc value of the identification of the node or device acting as the headend (a situation indicated in FIG. 3 by the symbol 122-y). Depending on whether the record RH includes a direct upstream route Ru, ie only the identification value of the head end is present in the record RH, or an indirect upstream route, ie the record RH also includes the identification value of a repeater member, the message MS is transmitted directly to the head end or the repeater member.

As previously mentioned, such transmission 123 of a service message MS can also be triggered by the reception 121 of a service message MS originating from a member of the same cluster and addressed to a device 10 implementing the joining method P100 and acting as a repeater member. Following the reception of such a service message MS originating from a member of the same cluster, step 121 can thus include a step for receiving and decoding such a message MS, and even for temporarily recording the data contained in the decoded service message MS in the data memory 12. The relaying of the message MS can thus be represented by retransmission at different times.

The communication method P100 according to the invention further comprises a process 130 for utilizing a cluster teardown message MR, such as the one previously mentioned, transmitted from the headend, and/or for interpreting a relay end message MF transmitted from a member that is no longer in a situation where its relay functionality is guaranteed due to appropriate capabilities CR or due to strict application of the cluster depth reduction requirements originating from the headend that has transmitted the recruitment message MH according to the invention. Such a process 130 of the communication method P100 according to the invention comprises a first step 131 for receiving a cluster teardown message MR or a relay end message MF formulated and transmitted by a third electronic communication device, for example the device 10i, which has previously qualified itself to function as a headend or a repeater member.

As previously discussed in connection with steps 114 and 115, the cluster teardown message MR includes the identifier IDR of the device that transmitted it. Process 130 then includes a step 132 for decoding the cluster teardown message MR and deducing from it the value of the identifier IDR of the device that transmitted it. Receipt of such a message MR by a device that is a member of the cluster to which the teardown message relates signifies the abandonment of the strict mandate of the cluster, with the member reverting to the status of a free node. To this end, process 130 of method P100 according to the present invention advantageously includes a step 133 for updating the record RH containing the current value IDHc of the identifier of the device that is acting as the headend, erasing it or replacing it with a predetermined value that reflects the absence of the identifier of the device that is acting as the headend. Obviously, this updating 133 of the record RH is only performed if (as indicated by the connection 134-y in connection with FIG. 5 ) the value of the identifier IDR deduced from the cluster teardown message MR is equal to the current value IDHc written in the record RH. The process 130 therefore comprises a step 134 , prior to step 133 , for carrying out said comparison of the value of the identifier IDR with IDHc.

Within the scope of the utilization of multi-hop networks, the message MR for tearing down the cluster can advantageously be relayed by the member made free by the implementation of step 133, just like the recruitment message MH, while triggering the transmission of such a message MR which is thus relayed to possible other member destinations of the cluster during the tearing down process.

Regarding the relay end message MF, step 131 involves deducing the identity of the transmitter device (denoted by IDF) and detecting information that characterizes the message MF as a relay end message. Receipt of such a message MF by a device that is a member of the same cluster and that is part of a downstream route from the transmitter device of the message MF represents a strict order to abandon the cluster, resuming free node status. Step 133 then involves updating the record RH in the data memory 12, specifically erasing the current value of IDHc or replacing it with a predetermined value that reflects the absence of the identity of the device acting as the headend. Obviously, this updating 133 of the record RH is only performed (as symbolized by connection 134-y in connection with FIG. 5 ) if the value of the identity IDF deduced from the relay end message MF is included in the upstream route Ru entered in the record RH (step 134).

Regardless of the configuration of the communication method P100 according to the present invention, the preferred adaptation mode of an electronic communication device, such as the device 10 for implementing such a method P100 described in association with Figure 2, consists in recording or downloading a computer program P through a program memory 14, said computer program P comprising a plurality of program instructions which, when executed or interpreted by the processing unit 11 of said device 10, cause the implementation of said communication method P100.

The invention has been described by means of a preferred application example associated with the monitoring of containers of goods, solid, fluid or liquid, said containers correspondingly cooperating with electronic communication devices, such as the devices 10 and 10i according to FIG. 2 , which implement a communication method, such as the method P100 illustrated by FIG. 5 , said devices each comprising a sensor 15 cooperating with a processing unit 11 for measuring and collecting quantities associated with the internal and/or external environment of said container.

Such devices can be used for any other application than that aimed at transmitting the collected data along long-distance links. As a variant or in addition, they can also ensure one or more other services. To this end, as we have already mentioned, the data memory 12 of each device 10, 10i can include not only a single record RH dedicated to the determined service S, but also a plurality of records RHn, forming, for example, a table, each dedicated to a specific service Sn. According to this variant, the recruitment message MH or MH', the service message MS, and even the message MR for tearing down the cluster or the relay end message MF will include information making it possible to identify the service Sn determined and involved by each of the said messages.

Furthermore, the present invention relates to any system comprising a plurality of electronic communication devices according to the present invention. More particularly, the present invention relates to any system for the traceability of containers on storage sites or transport platforms, said system also comprising a remote entity for collecting and utilizing messages MC transmitted from one or more of said devices when said devices function as headends. Such a system exhibits performance characteristics in terms of energy autonomy, robustness, and adaptability to utilization conditions that are unequal and incomparable to those imposed by known solutions, such as the LEACH method, for example. Indeed, thanks to the present invention, the utilization of the headend, from its selection to the implementation of one or more actions involved in the determined service, is optimized, preventing any unnecessary or ineffective communications within the network or to third-party destinations.

Claims (15)

1. A communication method (P100) in a network (N1) comprising multiple electronic communication devices (10, 10i, a1, ..., a8, b1, ..., b8, ..., e1, ..., e8), the method (P100) being implemented by a processing unit (11) of a first electronic communication device (10) in the network (N1), the first electronic communication device including, in addition to the processing unit (11), a data storage (12) and a first communication device (13), the first communication device (13) ensuring wireless proximity communication with a third electronic communication device (10i) of the network (N1) located within the communication range, the data storage (12) and the first communication device (13) cooperating with the processing unit (11), the data storage (12) including a value dedicated to the identifier of the first electronic communication device (10) and a record for storing the current value IDHc of the identifier of a second electronic communication device (d2) acting as a cluster head, the method (P100) comprising: - Step (101) is used to receive, via a first communication device (13) an invitation message created and transmitted by a third electronic communication device (10i) in the network (N1), the invitation message encoding an identifier of a second electronic communication device (d2) acting as a cluster head; - Step (102) is used to decode the recruitment message and infer from it the value of the identifier of the second electronic communication device (d2) acting as the cluster head and the value of the identifier of the third electronic communication device (10i) that has relayed the recruitment message in the appropriate case; - Step (103) is used to update the record such that the record stores the value of the identifier of the second electronic communication device acting as the cluster head, inferred from the decoded inbound message, as the current value IDHc of the identifier of the device acting as the cluster head, and, where appropriate, the record further stores the value of the identifier of the third electronic communication device (10i) as the uplink route Ru toward the second electronic communication device (d2) acting as the cluster head; The method (P100) is characterized by: - The recruitment message is further encoded with TTL data, which reflects the ability of the electronic communication device receiving the recruitment message to relay the recruitment message; - Step (102) for decoding the recruitment message and further inferring the value of the TTL data therefrom; - The step (103) for updating the record is adapted to store the current value of the TTL data that has been pre-decreased by one unit; And the method (P100) is characterized in that it includes: - A step for creating a relayed recruitment message, the message including: • The first field MH-1 encodes the current value IDHc of the identifier of the second electronic communication device (d2) that acts as the cluster header recorded in the record; • The second field MH-2 represents the uplink route Ru toward the second electronic communication device that acts as the cluster head, and encodes the identifier of the first electronic communication device (10); • The third field, MH-4, encodes the current value of the TTL data recorded in the record; - Step (106) is used to trigger the transmission of the relayed message through the first communication device (13) if the current value of the TTL data recorded in the comparison record is proved by the preliminary step (109) of the determined base value to be strictly greater than the base value. 2. The communication method (P100) according to claim 1, wherein: - The received recruitment message includes the following data CH: the data CH reflects the ability of the second electronic communication device, which acts as the cluster head, to ensure a given service; - The step (102) for decoding the recruitment message further infers the data CH embodying the capability from the recruitment message; - The step (103) for updating the record further includes recording in the record the value CHc of the data CH, which embodies the capability of the second electronic communication device (d2) acting as the cluster head. 3. The communication method (P100) according to claim 2, wherein step (103) for updating the record and recording therein the current value IDHc of the identifier of the electronic communication device acting as the cluster head is implemented only if the data CH embodying the capability is greater than or equal to the determined minimum threshold requirement. 4. The communication method (P100) according to any one of claims 1 to 3, comprising: - Step (131) is used to receive a relay termination message MF formulated and transmitted by a third electronic communication device (10i), the relay termination message MF including the identifier of the third electronic communication device (10i); - Steps for decoding the relay termination message MF and for inferring the value of the identifier from it; - Step (133) is used to update the record containing the current value IDHc of the identifier of the device acting as the cluster head, either to erase the current value IDHc or to replace the current value by a predetermined value reflecting the absence of the identifier of the device acting as the cluster head. The update of the record is only performed if the value of the identifier inferred from the relay end message MF is included in the record as an uplink route Ru toward the second electronic communication device (d2) acting as the cluster head. 5. The communication method (P100) according to any one of claims 1 to 3, wherein: -The preliminary step (109) involves comparing the current value of the TTL data recorded in the record with the determined base value. In addition, it involves generating a relay capability CR that is beneficial to the electronic communication device based on the functional parameters of the device, the electronic communication device belonging to the downlink route from the first electronic communication device (10), and comparing the generated capability CR with a predetermined minimum functional threshold. - The step (106) for triggering the transmission of the relayed message via the first communication device (13) is performed only if the generated capability CR is strictly greater than the predetermined minimum functional threshold. 6. The communication method (P100) according to any one of claims 1 to 3, wherein the step (103) for updating the record after the decoding of the incoming message further comprises, concurrently with the update of the record, triggering a means for measuring the duration, the communication method (P100) comprising the step (107) of comparing the duration with a predetermined maximum waiting period and for updating the record and erasing the current value IDHc of the identifier of the electronic communication device acting as a cluster head or replacing it with a predetermined value, the predetermined value reflecting the absence of an identifier of the electronic communication device acting as a cluster head. 7. The communication method (P100) according to claim 1, wherein: - The recruitment message includes a field MH-5 encoding TTL-e data and a field MH-6 encoding DST data, wherein the TTL-e data represents the maximum depth of the cluster desired by the second electronic communication device (d2) acting as the cluster head, and the DST data represents the distance that separates the transmitter electronic communication device of the recruitment message from the second electronic communication device (d2) acting as the cluster head in the downlink route. - Step (102) used to decode the recruitment message infers the values of the TTL-e and DST data from it; - The step (103) for updating the record is adapted to store the value of TTL-e data and the value of DST data that is pre-incremented by one unit; The method (P100) further includes the following step (107): the step is used to compare the values of TTL-e and DST recorded in the record and to update the record and erase the current value IDHc of the identifier of the electronic communication device that acts as the cluster head or replace it with a predetermined value, the predetermined value reflecting the absence of an identifier of a device that acts as the cluster head. 8. The communication method (P100) according to claim 1, comprising: -A step for determining the maximum depth Dp of the cluster that the first electronic communication device (10) wishes to serve as the cluster head, based on the operating parameters of the first electronic communication device (10); - Step (113) for encoding an admission message and triggering the transmission of the message by the first communication device (13), the message including a first field MH-1 and a second field MH-2, the first field MH-1 encoding the identifier of the first electronic communication device, the second field MH-2 encoding TTL data, the value of the TTL data being initialized to the maximum depth of the generated cluster. 9. The communication method (P100) according to claim 7, comprising: -A step for determining the maximum depth Dp of the cluster that the first electronic communication device (10) wishes to serve as the cluster head, based on the operating parameters of the first electronic communication device (10); - Step (113) for encoding an admission message and triggering the transmission of the message by the first communication device (13), the message including fields MH-1, MH-4, MH-5, MH-6 respectively encoded as follows: a. The identification of the device; b. Its value is recorded as TTL data in the record; c. Its value is initialized to the TTL-e data of the maximum depth Dp of the determined cluster; d. Its value is initialized to the DST data indicating the distance with zero hop count. 10. The communication method (P100) according to claim 8 or 9, comprising a step (111) for evaluating the capability of a first electronic communication device (10) to undertake a determined service, the step (111) being to estimate (1111) the operating parameters of the device (10) and to generate (1112) data CH, the data CH reflecting the capability of the device (10) to ensure the determined service, and for this purpose, the step for encoding an invitation message is to prepare a field MH-3 in the invitation message that encodes the data CH reflecting the capability prior to triggering the transmission (113) of the message by the first communication device (13). 11. The communication method according to claim 10 (P100) includes a step (112) for comparing data CH representing the capability with a required minimum functional threshold, and wherein the step (113) for triggering the transmission of an admission message is performed only if the data representing the capability is greater than or equal to the required minimum functional threshold. 12. A storage medium for a computer program including program instructions, said program instructions causing execution of the communication method (P100) according to any one of claims 1 to 11 upon experiencing any of the following: - Pre-recorded in the program memory (14) of the electronic communication device, which further includes a processing unit (11), a first communication device (13) for ensuring wireless proximity communication with any other electronic device within the communication range, and a data memory (12) for recording values dedicated to the identifier of the device and records including the current value of the identifier of the device acting as a cluster head, the memory (12, 14) and the first communication device (13) cooperating with the processing unit (11); -Executed or interpreted by the processing unit (11). 13. An electronic communication device comprising a processing unit (11), a data memory (12), a program memory (14), and a first communication device (13) for ensuring wireless proximity communication with any other electronic communication device within communication range, the memory (12, 14) and the first communication device (13) cooperating with the processing unit (11), the data memory (12) including values dedicated to the identification of the electronic communication device and records for including current values of the identification of the device acting as a cluster head, the electronic communication device being characterized in that it includes instructions for a storage medium for a computer program according to claim 12 in the program memory (14). 14. A system comprising a plurality of electronic communication devices according to claim 13. 15. The system of claim 14, comprising a plurality of containers for materials, solid, fluid or liquid cargo, the containers correspondingly cooperating with electronic communication devices, each of which includes a sensor (15) cooperating with a processing unit (11) for measuring and collecting quantities associated with the internal and/or external environment of the containers.