Method for managing communication channels within a wireless communication network, associated electronic object implementing the method and communication network

Abstract

The invention relates to a method (100) for managing wireless communication channels in order to allow, respectively, uplink communication (UL) to a hub / gateway device and downlink communication (DL) from the hub / gateway device. The method is intended to be implemented iteratively according to a predetermined activity period (T), by a processing unit specific to any electronic object belonging to a set of electronic objects forming a multi-hop communication network arbitrated by the hub / gateway device. Such a method (100) is designed such that phases of exclusive downlink (Ph1) and uplink (Ph2) communications are triggered during basic time units within the activity period (T) which are dependent on the rank (NR) of the electronic object within the communication network.

Description

[0001] Method for managing communication channels within a wireless communication network, electronic object implementing said method, and associated communication network

[0002] The invention relates to the field of wireless networks of communicating electronic objects designed for the "Internet of Things", a term associated with the acronym IoT, or better known under the English term "Internet of Things" and the acronym loT. This latter technology interconnects the internet to electronic objects, their environments. More specifically, the invention relates to a private wireless network protocol designed for such electronic objects to communicate with each other to form a communication network.

[0003] There are various communication networks that allow such data exchange between electronic devices. First, we can mention "broadband" cellular networks, similar to those ensuring communications between mobile phones. Such networks are dedicated to the exploitation of relatively large volumes of data exchanged. They require expensive licenses to be able to use specific frequency bands and are also particularly energy-intensive for the electronic devices to be connected.

[0004] Other communication networks for electronic objects are adapted to unit volumes of data exchanged lower than those permitted by a broadband cellular network. These networks are generally designated by the English acronym LPWAN (for "Low Power Wide Area Network"). These networks are low-power for electronic objects to be connected with respect to a cellular network and do not require any payment of frequency band operating licenses for some of them. Among these networks, we can cite Narrow Band loT or NB-loT (GSMA standard) derived from the cellular protocols LTE, Sigfox or LoRaWAN (trademarks registered respectively by Sigfox and Semtech Corporation) ensuring communications of a few dozen bytes per message. They do not allow independent two-way communications unlike a broadband cellular network.To limit their energy consumption, the objects to be connected can only be reached if they have previously sent a message to notify that they are listening for a limited period. LoRaWAN allows any operator to deploy its own network in exchange for the use of an electronic module ("chipset" in English terminology) delivered by the player Semtech. As shown in Figure 1, LoRaWAN is a communication protocol within a star communication network (each object communicates with one or more gateways) based on LoRa technology (a trademark registered and owned by Semtech Corporation). The latter, whose name is an acronym of the English expression "Long Range", allows low-speed communication between two points over long distances in the free frequency band of 868 MHz in Europe or 915 MHz in the USA.It is a radio modulation technology that serves as a physical medium for data transmissions according to different protocols such as LoRaWAN. LoRa uses the spread spectrum technique called CSS (acronym for "Chirp Spread Spectrum"). The available raw data rate depends on the choice of bandwidth (or "Channel Bandwidth" CB in English terminology), the spreading factor (or "Spreading Factor" SF in English terminology) and the coding rate (or "Coding Rate" CR in English terminology). The LoRaWAN protocol uses a fixed coding (CR = 4 / 5) and band (CB = 125KHz). The raw data rate varies from 15.625 Kbps (for SF = 5) to 0.293 Kbps (for SF = 12).In terms of geographical coverage, a gateway can receive messages from electronic objects within a radius of several kilometers (typically five to ten kilometers), for a radiated power of an electronic object of approximately twenty-five mW. The star-of-stars typology of a LoRaWAN network does not allow two objects of the network to communicate directly because they can only exchange with a gateway. As shown in Figure 1, such a protocol or network is called a "single-hop" or "single-hop" network. The geographical coverage of such a communication network is limited, not by the radio link budget, which is improved by the use of LoRa modulation, but by the number of objects at the edge of the radio range of the gateway.Many publications or studies highlight the saturation of the LoRaWAN network when the gateway has to manage too many objects using high spreading factors (SF > 10), which leads to an avalanche of collisions. To address this limitation, it is necessary to multiply the number of gateways in all directions to the detriment of the simplicity and cost of such a network. A LoRaWAN network, referenced NTW in Figure 1, thus comprises a plurality of sets of "low consumption" nodes referenced respectively N1-1 to N1-n, N2-1 to N2-m, Ng-1 to Ng-o, in the form of electronic objects in contactless links (represented by double white arrows) respectively with g gateways G1, G2, to Gg to communicate through the latter with application servers AS1, AS2, ..., ASs. The modulation technique used between the nodes and the gateways is LoRa.Communication between gateways and servers is established via the IP protocol using an Ethernet or cellular collection network symbolized by an NS server whose role is to arbitrate between gateways G1 to Gg. The "star" topology of the LoRaWAN network does not allow direct dialogue between two nodes N1-1 to N1-n, N2-1 to N2-m, Ng-1 to Ng-o, connected to the NTW network. If such a dialogue must take place, it is done through an application server among the servers AS1 to ASs. To overcome the saturation of a LoRaWAN network, scientific publications mention network typologies called "multi-hop" or "multi-hop" according to Anglo-Saxon terminology, based on LoRa modulation. Among these, we can cite the document by Zorbas Dimitrios and Fafoutis Xenofon, entitled "Time-Slotted Networks: Design Considerations, Implementations, and Perspectives", IEEE INTERNET OF THINGS MAGAZINE, IEEE, vol. 4, no.1, December 30, 2020, which explores different technical approaches based on LoRa modulation, seeking to compete with a LoRaWan network. This publication mentions a multi-hop solution based on LoRa radio modulation, called “Multi-hop LoRa” and described in more detail in the publication by Dinh Loc Mai and Myung Kyun Kim, entitled “MultiHop LoRa Network Protocol with Minimized Latency”, Energies, vol. 13 no. 6, March 15, 2020, XP093161054. However, Zorbas Dimitrios and Fafoutis Xenofon point out that this second publication does not clearly describe this multi-hop approach, in particular the management of communication channels or the activity ranges of the nodes in such a network. According to the said authors, such a solution seems to be based on an allocation of bidirectional communication channels by rank or according to the depth of the nodes within the network.The paper by Cong-Tan Duong and Myung Kyun Kim, entitled "Reliable Multihop Linear Network Based on LoRa", International Journal of Control and Automation, vol. 11 no. 4, April 30, 2028, XP093161060, describes an experiment in implementing a multi-hop communication network based on LoRa modulation in a surveillance or monitoring application. Such teaching seeks to reduce the risk of collision of messages sent by nodes within such a network, according to a purely ascending communication (monitoring), for which, after an initial stage of construction of the network and synchronization of the nodes of the latter, each node of said network remains mostly asleep and wakes up cyclically, to carry out a brief phase of activity consisting of listening and / or transmitting a message to nodes of lower ranks, the moment of such a wake-up of a node being a function of its rank and the depth of the network.Such teaching does not fit into an application combining competitive upward and downward communications.

[0005] The invention solves the previously mentioned drawbacks. Among the many advantages provided by a protocol according to the invention, we can mention:

[0006] - an implementation not requiring a pre-established infrastructure; - control of the reception of an electronic object applying to the communication network;

[0007] - a capacity granted to electronic objects that are members of a network to be able to organize themselves dynamically to implement a so-called multi-hop topology (multi-hop according to Anglo-Saxon terminology) allowing direct communication between objects and optimal communication towards a gateway;

[0008] - wide geographic coverage without risk of collision of messages from comparatively distant objects in the “one hop” sense of LoRaWAN;

[0009] - particularly optimized energy consumption allowing a long lifespan of communication within a network, particularly due to the fact that a concentrator / gateway device according to the invention can operate on batteries for much longer (i.e. by a factor of up to ten, for the same storage capacity) than the gateways of a LoRaWAN network;

[0010] - the ability to request any node or electronic object on the network at any time with very low latency (less than a minute) without an object having to send a message to indicate that it is listening for a predetermined period;

[0011] - a very advantageous implementation of LoRa technology.

[0012] To this end, the invention provides a method for managing communication channels to ensure low-speed wireless communication over long distances, respectively uplink to a hub / gateway device and downlink wirelessly from said hub / gateway device, said method being arranged to be implemented iteratively according to a predetermined activity period, by a processing unit specific to any first electronic object belonging to a set of electronic objects forming a multi-hop communication network arbitrated by said hub / gateway device and comprising:

[0013] - steps for opening and closing a first communication channel dedicated to downward communication;

[0014] - steps of opening and closing a second communication channel dedicated to upward communication, said first and second communication channels being distinct.

[0015] In order for the electronic objects of the communication network to be able to organize themselves dynamically and implement a so-called multi-hop topology allowing direct communication between said objects, such a method is designed so that the activity period is subdivided into a predetermined number Tlln of elementary time units and so that:

[0016] - the steps of opening the first communication channel and closing the second communication channel, mutually constituting an exclusive downward communication phase, are triggered during a first elementary time unit within the activity period whose index t1 is a function of the rank of said first electronic object and implemented for a first predetermined duration;

[0017] - the steps of closing the first communication channel and opening the second communication channel mutually constituting an exclusive ascending communication phase, are triggered during a second elementary time unit within the activity period whose index t2 is also a function of the rank of said first electronic object and implemented for a second determined duration, the sum of said first and second durations not exceeding the activity period.

[0018] According to an advantageous embodiment:

[0019] - the value of the index t1 can be between 0 and Tlln-1 and can be determined by the operation t1 = [A1 + (NR-1 ) * DLd / 2] modulo T, DLd being the first predetermined duration of implementation of the exclusive downlink communication phase, NR being the rank of said first electronic object within the communication network in the form of a strictly positive integer value and less than or equal to a predetermined maximum rank value NRmax, A1 being a first time offset in the form of a predetermined integer number of elementary time units greater than or equal to zero;

[0020] - the value of the index t2 can be between 0 and Tlln-1 and can be determined by the operation t2=[ A1 +(NR+1 )*DLd / 2+A2] modulo T, A2 being a second time shift in the form of a predetermined integer number of elementary time units greater than or equal to zero.

[0021] To meet European and North American telecommunications standards, one embodiment of a method according to the invention may consist of:

[0022] - the predetermined values ​​of said first and second time shifts A1 and A2 are zero;

[0023] - the predetermined value of the activity period T is equal to twenty seconds, said activity period T comprising a number Tlln equal to twenty elementary time units of one second each;

[0024] - the predetermined value of the first duration DLd is equal to four seconds;

[0025] - the predetermined value of the maximum rank NRmax of an electronic object part of the communication network (NTW) is equal to nine.

[0026] To circumvent European requirements in particular, the step of opening the first communication channel can advantageously consist of the exploitation, according to a technique called "duplex by time separation", of the first communication channel by the implementation:

[0027] - a first sub-method for selecting said first communication channel, listening to and receiving any message sent by a second electronic object of the set of electronic objects forming the communication network of rank immediately lower than the rank NR of the first electronic object;

[0028] - a second sub-method of transmission by said first communication channel of a message intended for all third electronic objects, the set of electronic objects forming the communication network of rank immediately higher than the rank NR of the first electronic object.

[0029] In this case, to avoid drawing unnecessarily on the energy resources of said very first electronic object, said second sub-method of transmission by said first communication channel of a message intended for all third electronic objects of the set of electronic objects forming the communication network may only be implemented if the rank NR of the first electronic object is strictly lower than the maximum rank NRmax of said network.

[0030] According to a preferred embodiment when the step of opening the first communication channel consists of the exploitation, according to a technique called “duplex by time separation”, of the first communication channel, said first and second sub-methods can be implemented one after the other, each for a duration equal to half of the first duration DLd.

[0031] Whatever the embodiment of a method for managing communication channels according to the invention, the step of opening the second communication channel of such a method may consist of the exploitation of the second communication channel by implementing:

[0032] - a first sub-method for selecting said second communication channel so that it is distinct from the first communication channel, for listening and transmitting by said second communication channel a message to a second electronic object of the set of electronic objects forming the communication network of rank immediately lower than the rank NR of the first electronic object, when such a message has been previously developed;

[0033] - a second sub-method: o listening to and receiving any message sent by third electronic objects of the set of electronic objects forming the communication network of rank immediately higher than the NR rank of the first electronic object, said message being addressed to said first electronic object and, o transmitting by said second communication channel a message to a second electronic object of the set of electronic objects forming the communication network of rank immediately lower than the NR rank of the first electronic object, when such a message has been previously prepared;

[0034] - a third sub-method for listening to and receiving any message sent by third electronic objects of the set of electronic objects forming the communication network of rank immediately higher than the rank NR of the first electronic object, said message being addressed to said first electronic object.

[0035] To avoid unnecessarily drawing on the energy resources of any first electronic object implementing a method for managing communication channels in accordance with the invention, it may be provided that the second and third sub-methods of the step of opening the second powerful communication channel consist of listening to and receiving any message sent by third electronic objects of the set of electronic objects forming the communication network of rank immediately higher than the rank NR of the first electronic object, said message being addressed to said first electronic object if and only if the value of the rank NR of the first electronic object is strictly lower than the predetermined value NRmax.

[0036] Whatever the embodiment of a method for managing communication channels in accordance with the invention, to synchronize all the electronic objects forming the communication network and thus “align” the activity periods T, such a method may include a processing operation for parameterizing the implementation of said method, said processing operation comprising:

[0037] - a step of detecting the reception of a BEAT-Mg message discriminable among all other messages transmitted via the first communication channel dedicated to downlink communication and reading said BEAT-Mg message to determine the rank of its transmitter, said BEAT-Mg message conveying said rank of said transmitter;

[0038] - a step of calculating the value of the rank NR of said first electronic object consisting of incrementing by one unit the value of the rank of the transmitter of the BEAT-Mg message read in the previous step;

[0039] - a step of triggering the initialization of the internal clock in the processing unit of the first electronic object and therefore of the period of activity.

[0040] According to this advantageous embodiment and in order to propagate such synchronization, a method for managing communication channels in accordance with the invention may comprise a step of relaying a BEAT-Mg message to any third object located within radio communication range and listening to a transmission on said first communication channel dedicated to downlink communication, said step consisting of developing a new BEAT-Mg message conveying the NR value of the rank of said first electronic object and causing the transmission of said message via the first communication channel dedicated to downlink communication.

[0041] Still with a view to preserving the energy resources of any first electronic object implementing a method for managing communication channels in accordance with the invention, said step of relaying a BEAT-Mg message may only be implemented if the rank NR of said first electronic object is strictly lower than the predetermined maximum rank value NRmax.

[0042] In addition to synchronizing the clocks of electronic objects in a communications network in accordance with the invention, the latter provides that:

[0043] - a BEAT-Mg message can convey a parameter for implementing the communication channel management method from among a set of parameters, said set of parameters comprising the activity period, the number Tlln of elementary time units of said activity period, the first duration of implementation of the steps of opening the first communication channel and closing the second communication channel mutually constituting an exclusive downward communication phase, the value of the maximum rank NRmax supported by the communication network (NTW), the first and / or second time offsets A1 and A2;

[0044] - the step of reading said BEAT-Mg message may further consist of reading the value of said parameter for implementing said method and recording said value of said parameter in a data memory of the first electronic object;

[0045] - said method may further comprise a step for reading the value of said parameter and configuring the implementation of said method on the basis of said value of the parameter read.

[0046] To propagate such a setting within the communication network, the step of relaying a BEAT-Mg message of a communication channel management method according to the invention may consist of developing a new BEAT-Mg message conveying the NR value of the rank of said first electronic object and of the implementation parameter of said method.

[0047] Regardless of the embodiment of a communication channel management method according to the invention, the invention provides for the ability to maximize the net useful throughput of a downlink communication within the communication network and prevent the risk of saturation of electronic objects acting as relay nodes. For this purpose, a communication channel management method according to the invention may include data aggregation processing implemented before any transmission along the first communication channel dedicated to a downlink communication. Such aggregation processing may include:

[0048] - a step of: o detecting the reception of said first communication channel, of an incoming message emanating from a second electronic object of a rank immediately lower than the NR rank of said first electronic object receiving said message; o reading said incoming message and developing data to be transmitted to a third electronic object of a rank immediately higher than the rank of said first electronic object;

[0049] - a step of aggregating all data intended for such a third electronic object so as to form an outgoing message of a size greater than or equal to a predetermined minimum threshold;

[0050] - a step of waiting for the opening of said first communication channel while it is closed;

[0051] - a step of triggering the transmission of the outgoing message as soon as said first communication channel is open.

[0052] According to this advantageous embodiment, for an object to also transmit measurement or operating data specific to it, such a method may include a step of producing data external to any message entering via said first communication channel, said data produced being intended to be transmitted to any third electronic object of a rank immediately higher than the NR rank of said first electronic object.

[0053] Still with a view to preserving the energy resources of any first electronic object implementing a communication channel management method in accordance with the invention, said aggregation processing may only be implemented if the rank of said first electronic object is strictly lower than the maximum rank NRmax supported by the communication network.

[0054] In the same way and whatever the embodiment of a method for managing communication channels according to the invention, the latter provides for being able to maximize the net useful flow rate of an uplink communication within the communication network and prevent the risk of saturation of electronic objects acting as relay nodes. For this, a method for managing communication channels according to the invention may comprise a data aggregation processing implemented before any transmission according to the second communication channel dedicated to an uplink communication. Such an aggregation processing may comprise:

[0055] - a step of: o detecting the reception via the second communication channel, of an incoming message emanating from a third electronic object of a rank immediately higher than the rank of said first electronic object receiving said message; o reading said incoming message and developing data to be transmitted to a second electronic object of a rank immediately lower than the rank of said first electronic object;

[0056] - a step of aggregating all data intended for such a second electronic object so as to form an outgoing message of a size greater than or equal to a predetermined minimum threshold;

[0057] - a step of waiting for the opening of said second communication channel while the latter is closed;

[0058] - a step of triggering the transmission of the outgoing message as soon as said second communication channel is open.

[0059] Like a downward communication possibly optimized by this aggregation technique, a method according to the invention may include a step of producing data exogenous to any incoming message via said second communication channel, said data produced being intended to be transmitted to a second electronic object of a rank immediately lower than the NR rank of said first electronic object.

[0060] According to a second object, the invention relates to an electronic object comprising:

[0061] - a processing unit comprising a clock;

[0062] - a data memory;

[0063] - a program memory;

[0064] - wireless means of communication with the outside world;

[0065] - a source of electrical energy in the form of one or more batteries.

[0066] To resolve all or part of the drawbacks of the state of the art, the processing unit can be arranged to implement a method for managing communication channels in accordance with the invention.

[0067] According to a third object, the invention relates to a communication network comprising a concentrator / gateway device and a plurality of electronic objects as defined previously.

[0068] According to a fourth subject, the invention relates to a computer program product comprising one or more program instructions interpretable by a processing unit of an electronic object which is a member of such a communication network, said program instructions being loadable into the program memory of said object and designed so that the execution of said instructions by said processing unit causes the implementation of a method for managing communication channels in accordance with the invention.

[0069] Finally, according to a fifth object, the invention relates to a computer-readable storage medium comprising the instructions of such a computer program product. Other characteristics and advantages will appear more clearly on reading the description which follows and on examining the figures which accompany it, among which:

[0070] - figure 1, already described, illustrates an example of a known communication network implementing a LoRaWAN type protocol or method;

[0071] - figure 2 illustrates an example of functional architecture of an electronic object forming such a communication network according to figure 1;

[0072] - figure 3 illustrates an example of a communication network implementing a protocol or method in accordance with the invention;

[0073] - figure 4 illustrates an example of a protocol implemented by a plurality of nodes of a network according to the invention ensuring upward and downward communications;

[0074] - figure 5 illustrates such an example of a protocol implemented by a plurality of nodes of a network according to the invention in the absence of upward communications;

[0075] - figure 6 illustrates a method for managing communication channels implemented by any electronic object adapted according to the invention to be one of the nodes of a multi-hop communication network according to figure 3;

[0076] - figure 7 illustrates an example of a service for opening a downlink communication channel of a protocol according to figure 6 implemented by a plurality of nodes of a multi-hop communication network according to figure 3;

[0077] - Figure 8 illustrates an example of a service for opening an upward communication channel of a protocol according to Figure 6 implemented by a plurality of nodes of a multi-hop communication network according to Figure 3;

[0078] - figure 9 illustrates an example of a synchronization service for the implementation of a communication channel management method according to the invention and illustrated by figure 6, said service being implemented by any node of a multi-hop network such as that illustrated by figure 3;

[0079] - figure 10 illustrates an example of a message aggregation service in accordance with the invention and implemented by any node of a network such as that illustrated by figure 3, to optimize the communication flows via the ascending and descending communication channels controlled according to a communication channel management method in accordance with figure 6.

[0080] Let us preferentially but not limitatively describe the invention through an example of arrangement of an electronic object Ni intended to be one of the nodes of a wireless communication network, such as a LoRaWAN network or a network in accordance with the invention, as described later in connection with figure 3.

[0081] As shown in Figure 1, any NTW communication network comprises a plurality of electronic entities, in this case electronic objects N1-1 to N1-n, N2-1 to N2-m, Ng-1 to Ng-o. Conventionally and as illustrated in a simplified manner in Figure 2, each of said electronic objects consists of an instance Ni of an object comprising a central processing unit 11 controlling, by signals routed by a communication bus symbolized in Figure 2 by double arrows in single lines, electronic elements including a memory. The latter comprises a data memory 12 and a program memory 13, said memories 12 and 13 being able to form a single physical entity. The term "memory" means any computer memory, whether volatile or not. A non-volatile memory is a computer memory whose technology retains its data in the absence of an electrical power supply.It can contain data resulting from inputs, calculations, measurements and / or program instructions. The main non-volatile memories currently available are electrically writable such as EPROM technology (Erasable Programmable Read-Only Memory) or electrically writable and erasable such as EEPROM technology (Electrically-Erasable Programmable Read-Only Memory), flash, SSD (Solid-State Drive), etc. Non-volatile memories are distinguished from so-called "volatile" memories, the data of which is lost in the absence of a power supply.The main volatile memories currently available use RAM (Random Access Memory), DRAM (dynamic random access memory, requiring regular updating), SRAM (static random access memory requiring such updating during a power shortage), DPRAM or VRAM (particularly suitable for video), etc. technologies. Such a data memory generally includes a unique identifier IDi distinguishing said electronic object from its peers. According to Figure 2, an electronic object Ni may also include one or more sensors 13 for measuring its environment, or even control an actuator not shown in Figure 2. Such an electronic object Ni includes means of communication 15 with the outside world in the form of an input unit and an output unit.Said communication means 15 cooperate with the processing unit 11 and ensure wireless proximity communication with any other electronic object Nn of a network according to the invention or with a gateway G1 to Gg according to the example of an NTW network described in connection with FIG. 1. To operate, such an electronic object Ni generally comprises an electrical energy source 16, external or internal in the form of one or more batteries for example. The processing unit 11 may also comprise control means 17 of an input and / or output human-machine interface 17. The term “output human-machine interface” means any device, used alone or in combination, making it possible to output or deliver a graphic, haptic, sound or, more generally, human-perceptible representation. Such an output human-machine interface may consist, in a non-exhaustive manner, of one or more screens, speakers or other suitable alternative means.The term "human-machine input interface" means a computer keyboard, a pointing device, a touch screen, a microphone or, more generally, any interface designed to translate gestures or instructions issued by a human into control or configuration data. Advantageously, the human-machine input and output interfaces may constitute a single physical entity.

[0082] A communication network can be adapted by loading into the program memory 13 of each electronic object Ni a computer program P comprising instructions to cause, during their execution, the implementation of a suitable method. This computer program P can use any programming language, and be presented in the form of source codes, object codes, or intermediate codes between source codes and object codes, such as in an interpreted, partially or fully compiled form, or in any other desirable form.

[0083] Figure 3 illustrates an example of an NTW communication network implementing a method or protocol according to the invention. As indicated in said figure 3, the NTW network is not necessarily a star network. Thus, two communicating nodes within the NTW network can establish direct uplink and downlink communications, i.e. without having to go via a gateway. For this, it is sufficient for them to be within radio communication range. When two nodes are physically too far from each other to establish direct radio communication, the latter can establish such indirect communication via one or more peer nodes relaying messages. The typology of a communication network according to the invention is therefore called "multi-hop" or "multi-hop" according to English terminology. Thus, an NTW communication network may comprise only one concentrator / gateway device CG and one application server AS1.Such a CG device consists of a microstation, advantageously portable and mobile, providing a dual function of gateway, stimulator and / or arbiter of the NTW network. Such a stimulator and / or arbiter function may consist of the propagation of a PNI (Private Network Identifier) ​​or any other attribute characterizing the membership of an electronic object to a specific family of nodes forming the NTW network or conversely in the verification of the effective membership to such a family of a node applying to join the NTW network. The electronic objects forming the NTW network have the capacity to self-organize to offer, dynamically because all or part of said objects may be mobile, an upward route solution to the CG concentrator / gateway device or downward route solution from the latter.Thus, at a given time, as shown in Figure 3, a node N1 -1 can communicate directly with the hub / gateway device CG and with two nodes N1 a-2 and N1 b-2 respectively. The latter can communicate directly with node N1 b-3 which can, in turn, communicate directly with node N1 b-4. The latter is considered a level 4 node in the NTW network tree with respect to the level 0 hub / gateway device CG. The same is true for node N1 a-2 which can communicate directly with node N1a-3 of level 3 in the NTW network tree.

[0084] Depending on the relative geographical location of the other nodes of the NTW network according to Figure 3, the hub / gateway device CG can establish direct communication with two other nodes N2-1 and N3-1. The node N2-1 located within radio communication range of the node N2-2 can communicate directly with the latter. On the other hand, the node N2-2 cannot communicate directly with the hub / gateway device CG because it is physically too far from the latter. Depending on certain conditions, the example in Figure 3 indicates that said node N2-2 can also communicate with the node N1 a-2. Thus, depending on the environmental conditions, such a node N2-2 can have a plurality of ascending or descending routes to communicate with the application server AS1 via the hub / gateway device CG by means of the relay node N2-1 or N1 a-2. Said node N2-2 can thus be considered alternatively as level 2 or level 3 in the NTW network tree.We will detail later the processing according to the invention of such a situation. According to said figure 3, the node N3-1 (level 1) can communicate directly with a second node N3-2 located within radio communication range, the latter being able in turn to communicate directly with two other nodes N3a-4 and N3b-4, geographically too far from the node N3-1 to establish direct communication with the latter. Finally, a node N3b5 can in turn communicate directly with the N3b-4. This last node N3b-5 is a level 5 node in the tree structure of the NTW network. Five hops or relays are necessary for it to communicate with the concentrator / gateway device CG and thus with the application server AS1. As previously stated, such an NTW network can have the capacity to modify its typology and therefore the ascending and descending routes, according to changes in the environment or relative movements of such or such nodes.Figure 3 is therefore a view that describes the communication routes between the nodes of the NTW network at a given time. There are different protocols for automatic route arrangement within a multi-hop contactless communication network. However, an NTW network according to the invention is arranged to meet many constraints which sets it apart from its peers.

[0085] Thus, from a node of an NTW network according to the invention, the radio coverage and the quality of service are similar to those offered by LPWANs, such as Sigfox or LoRaWAN for example, while inducing lower ownership and operating costs. Furthermore, any node of the NTW network can be interrogated by the CG concentrator / gateway device at any time with very low latency, i.e. less than a minute and finally the geographical coverage can be increased to a radius of around ten kilometers, or even more. Thus, thanks to a multi-hop typology, nine hops make it possible to reach a radius of nine kilometers for a radiated power of approximately twenty-five mW.

[0086] An NTW network in accordance with the invention is not limited to the implementation of LoRa technology. It is sufficient to rely on any radio technique or modulation capable of implementing low-speed communication over long ranges, as proposed by Sigfox, for example. However, an NTW network in accordance with the invention will favor a solution using unlicensed and authorized frequency bands in European and North American territories.

[0087] As such, an NTW network in accordance with the invention satisfies a double limitation arising from the operation of such frequency bands without an operating license. The first limitation concerns the maximum authorized transmission power. The operation of LoRa makes it possible to satisfy this first limitation since Semtech's electronic modules limit such power to twenty-five mW in Europe, for example. The second limitation imposed by the operation of such frequency bands concerns the maximum duration of use of a communication channel or a frequency band within a given time range. The European regulations in force require not to transmit on the same channel more than 1% of the time over a period of one hour.

[0088] Thus, according to the European Telecommunications Standards Institute (ETSI), it is not possible to operate a frequency band for more than thirty-six seconds over a one-hour period without having to change the communication channel (200kHz band). To circumvent this constraint, it is known to use the technique known as "LBT + AFA" (acronyms for "Listen Before Talk" and "Automatic Frequency Agility") so that the operating percentage is increased to 2.78% of the activity period. According to this technique, a transmitter listens to its radio environment before starting a transmission to ensure that it communicates via a free communication channel.To implement such a verification, the invention provides that the LBT function can be implemented according to the “Carrier Sense Multiple Access with Collision Avoidance” algorithm, also known by the acronym CSMA / CA, a distributed algorithm which allows sharing of a medium while reducing the probability of collisions, as used in Wi-Fi for example.

[0089] The Federal Communications Commission ("FCC") imposes a sliding activity period not exceeding twenty seconds (20dB band below 250kHz per channel).

[0090] To meet the requirements of the two regulations mentioned above, the invention advantageously provides for an activity period T of twenty seconds. Thanks to the implementation of the “LBT+AFA” technique, a channel or a frequency band can be occupied for up to four hundred milliseconds over said activity time range T of twenty seconds, i.e. 2% of said period T. After four hundred milliseconds, the invention provides for the use of another channel. The invention would not, however, be limited to this choice of parameterization of the activity period T (twenty seconds) and the maximum operating duration of a channel to 2% of the latter. Any other parameterization could be chosen according to the local regulations in force (for example, a maximum occupancy rate of a channel of 2.5% of an activity period of thirty-two seconds).

[0091] The electronic objects forming an NTW network according to the invention are advantageously based on LoRa technology. They therefore all operate in "half duplex" mode, i.e. they cannot transmit and receive at the same time. An NTW network according to the invention (as illustrated in Figure 3) allows a concentrator / gateway device CG to request a node of the network at any time. For this, a node receiving a request from said concentrator / gateway device CG must be listening when said request (possibly relayed) reaches it. As shown in Figure 4, each node of an NTW network arranged according to the invention systematically implements a downlink communication slot DL of a duration DLd at each activity period T. According to an advantageous embodiment, the duration DLd of such a downlink communication slot DL is four seconds for an activity period advantageously equal to twenty seconds.The rest of the time, in this case a duration ULd equal to sixteen seconds according to the example in Figure 4, the activity period T being twenty seconds, an ascending communication channel UL is opened, in a non-systematic manner. Indeed, a node of the NTW network is only required to communicate with a lower-ranking node if it has something to transmit or retransmit to it, as will be detailed later. In Figure 4, it appears that the activity period T is subdivided into twenty time units, of one second each, noted respectively TU0 to TU19. The time units TU dedicated to a descending communication slot DL appear in black background blocks including a vertical arrow pointing downwards in white, unlike the time units dedicated to an ascending communication UL which appear in white background blocks including a vertical arrow pointing upwards in black.

[0092] More specifically, the invention provides that a DL downlink communication slot reserved by a node of rank NR is subdivided into two parts or two sub-slots. The first part is dedicated to receiving a message sent by a node of lower rank NR-1. The second part is dedicated to sending all or part of said message received to any node of higher rank NR+1, located within radio communication range. According to the invention, the DL downlink communications are implemented by any node of rank NR of an NTW network in “broadcast” mode, i.e. to all nodes of higher rank NR+1 located within radio communication range of the transmitting node of rank NR.

[0093] For this, each electronic object Ni to become a node of a communication network according to the invention is adapted to implement a method for managing communications channels such as the method 100 illustrated by way of example in FIG. 6. Such a method 100 for managing communications channels to respectively ensure a wireless uplink communication UL to a concentrator / gateway device CG and a wireless downlink communication DL from said concentrator / gateway device CG, is arranged to be implemented iteratively according to a predetermined activity period T, by a processing unit 11 specific to any first electronic object belonging to a set of electronic objects forming the multi-hop communication network NTW arbitrated by said concentrator / gateway device CG.

[0094] Let a first node of rank NR=1 such as the node N1-1, N2-1 or N3-1 described in figure 3, said first node being an electronic object arranged such as the object Ni described previously in connection with figure 2. As indicated in figures 4 and 6, after a step 101 of initialization of an internal clock specific to said node and generally internal to the processing unit 11 of the latter (in response to the implementation of a synchronization service 200 specific to the invention and described later in connection with figure 9), a method of managing communication channels 100 comprises:

[0095] - steps of opening 111 and closing 121 of a first communication channel dedicated to downward communication DL;

[0096] - steps of opening 122 and closing 112 a second communication channel dedicated to upward communication UL, said first and second communication channels being distinct.

[0097] Step 112 is symbolized in Figure 6 by a step block comprising an oblique segment crossing out the word “UL”. The triggering of the implementations of steps 111 and 112 are concomitant and initiate a first phase referenced Ph1 in Figure 6 which extends over a first duration DLd predetermined as an operating parameter of the nodes Ni of the NTW network. In this case, in the example illustrated by Figure 4, such a first duration DLd is set at four seconds within an activity period T of twenty seconds.

[0098] The rest of the time (second duration ULd allocated to the upward communication, in this case in the example of figure 4, sixteen seconds), the method 100 consists of implementing the steps of opening 122 and closing 121 of the second communication channel dedicated to the downward communication DL. Step 121 is symbolized in figure 6 by a step block comprising an oblique segment crossing out the word "DL". The triggering of the implementations of steps 121 and 122 are concomitant, close the first phase Ph1 and initiate a second phase referenced Ph2 in figure 6. Such a method 100 thus alternates the phases Ph1 and Ph2 according to the activity period T. Such an alternating operation of two distinct communication channels respectively dedicated to an upward communication UL and a downward communication DL makes it possible in particular to prevent, or greatly reduce, the risks of message collisions between neighboring nodes in the same "communication space".Such a technical effect will become clear from the detailed description of the invention in connection with Figures 7 and 8.

[0099] So that, whatever a first node of rank NR within an NTW communication network, it is able to listen at opportune times and receive one or more messages emanating from peer nodes located within radio communication range, i.e. nodes of a rank immediately lower NR-1 or of a rank immediately higher NR+1 than the NR rank of said first node, a method for managing the communications channels 100 in accordance with the invention comprises steps 102 and 103 of respective triggering of the two phases Ph1 and Ph2 as mentioned previously which take into account the NR rank of said first node in the NTW communications network.

[0100] Thus, more precisely, the steps of opening 111 of the first communication channel and closing 112 of the second communication channel, mutually constituting a first exclusive downward communication phase Ph1, are triggered during a first elementary time unit TU within the activity period T whose index t1 is a function of the rank NR of said first electronic object, said first phase Ph1 extending over a first predetermined duration DLd.The value of said index t1, between 0 and TUn-1, TUn being the number of elementary time units TU within the activity period T, is determined by the operation t1 = [A1 + (NR-1 ) * DLd / 2] modulo T, DLd being the first predetermined duration of implementation of the exclusive downlink communication phase Ph1, the rank NR of said first electronic object being in the form of a strictly positive integer value and less than or equal to a predetermined maximum rank value NRmax and A1 being a first optional time offset, which we can express in the form of a predetermined integer number of elementary time units TU greater than or equal to 0. As a non-limiting example illustrated by Figure 6, the value of said time offset A1 is zero.For an activity period T of twenty seconds subdivided into TUn=20 elementary time units of one second each, phase Ph1 (steps 111 and 112) is triggered (link 102-y in figure 6) during:.

[0101] - the elementary time unit TUO, for any node of rank NR=1 such as the electronic object N3-1 in figure 3;

[0102] - the elementary time unit TU4 for any node of rank NR=2 such as the electronic object N3-2 in figure 3;

[0103] - the elementary time unit TU8 for any node of rank NR=5 such as the electronic object N3b-5 in figure 3, etc.

[0104] In the same way, the second exclusive phase Ph2 of upward communication UL corresponding to the steps of closing 121 of the first communication channel and opening 122 of the second communication channel are triggered during a second elementary time unit TU within the activity period T whose index t2 also depends on the rank NR of any first electronic object implementing a method 100 according to the invention. This second phase Ph2 extends over a second predetermined duration ULd, the sum of said first and second durations DLd, ULd not exceeding the activity period T. The second duration ULd can be reduced, for example, by exploiting a second time shift A2 triggered at the end of the implementation of the first phase Ph1, the two communication channels then remaining closed.Such a second time shift A2, like the first shift A1, can be expressed in the advantageous form of an integer number of elementary time units TU and is optional. Its value can therefore be zero as is the case in the example illustrated by figure 4.

[0105] The value of the index t2 is thus between 0 and TUn-1 and is determined by the operation t2=[ A1 +(NR+1 )*DLd / 2+A2] modulo T.

[0106] For a predetermined value of the first duration DLd of phase Ph1 equal to four seconds and a zero value A2, as indicated in figures 4 and 6, phase Ph2 (steps 121 and 122) can be triggered at the end of phase Ph1, during:

[0107] - the elementary time unit TU4, for any node of rank NR=1 such as the electronic object N3-1 in figure 3;

[0108] - the elementary time unit TU6 for any node of rank NR=2 such as the electronic object N3-2 in figure 3;

[0109] - the elementary time unit TU12 for any node of rank NR=5 such as the electronic object N3b-5 in figure 3, etc.

[0110] The invention provides that the steps of opening 111 and closing 121 of the first communication channel dedicated to a downward communication DL are systematically implemented, at each period of activity T or iteration of the method 100. On the other hand, the exploitation 122 of the second communication channel to receive RXO and / or transmit TXO a message according to an upward communication UL may not be systematic, that is to say that such a second channel is “open” for this operation at the discretion of the electronic object implementing the method 100 to optimize the energy consumption of said electronic object.

[0111] Figures 7 and 8 respectively describe the steps of opening a first communication channel dedicated to a downward communication DL and of opening a second communication channel dedicated to an upward communication UL. The steps 112 and 121 of closing a communication channel are symbolized by the English word "OFF" in Figure 4 during the elementary time units during which said channel is closed and do not merit being described in more detail.

[0112] On the other hand, in connection with Figure 7, let us study more precisely step 111 of the method for managing the communications channels 100 illustrated by way of example by Figures 4 and 6. As mentioned previously, the invention provides that a downlink communication slot DL reserved by a node of rank NR is subdivided into two parts or two sub-slots, respectively dedicated to the reception of a message transmitted by a node of lower rank NR-1 and to the transmission of all or part of said message received to any node of higher rank NR+1 if said node is located within radio communication range. Figure 7 illustrates, at each elementary time unit TU of the activity period T from the triggering (link 102-y in Figure 6) of the phase Ph1, the sub-steps implemented by the processing unit of any first electronic object among the set of electronic objects adapted according to the invention forming a wireless communication network NTW.

[0113] Step 111 of opening the first communication channel (or first frequency band) implemented by any first electronic object taken from the set of electronic objects forming the NTW communication network thus consists of the exploitation, according to a technique called “time division duplexing” or also known by the English terminology “Time Division Duplexing - TDD”, of the first communication channel by the implementation:

[0114] - a first sub-method for selecting said first communication channel, listening and receiving any message sent by a second electronic object of the set of electronic objects forming the NTW communication network of rank immediately lower NR-1 than the rank NR of the first electronic object;

[0115] - a second sub-method of transmission by said first communication channel of a message intended for all third electronic objects of the set of electronic objects forming the communication network NTW of rank immediately higher NR+1 than the rank NR of the first electronic object.

[0116] Thus, as shown in Figure 4 in connection with Figure 7, said second sub-method of transmission by said first communication channel of a message intended for all third electronic objects of the set of electronic objects forming the communication network NTW can advantageously only be implemented if (situation illustrated by the link 111 cn in Figure 7) the rank NR of the first electronic object is strictly lower than the maximum rank NRmax of said network NTW, in this case in the example illustrated by Figure 4, NRmax is predetermined as being equal to the value 9.

[0117] We can further note in this advantageous example that said first and second sub-processes are implemented one after the other, each for a duration equal to half the duration DLd of phase Ph1.

[0118] The first sub-process of step 111 (first phase Ph1 in Figure 6 and represented by elementary time units with a black background in Figure 4) consists first of all of a sub-step 111 a of selecting the first communication channel distinct from that which will be used for the ascending communications UL, and of listening and therefore of possible reception of any message emanating from a second electronic object of lower rank NR-1. Such listening by means of said first communication channel is referenced RX1 in Figures 7 and 4. The invention provides, in order to circumvent in particular the European requirements, as mentioned previously, that said first sub-process can advantageously comprise a sub-step 111 b (referenced RX in Figures 7 and 4) of receiving data by using the AFA technique (Automatic Frequency Agility according to English terminology).

[0119] The second sub-method of said step 111 consists of a sub-step 111 d of exploitation of said first communication channel, arranged no longer to receive data emanating from a second electronic object of lower rank NR-1, but to transmit all or part of the data received to third electronic objects (or nodes of the NTW network) of the rank immediately higher NR+1 than that of the first electronic object, if said third electronic objects are within radio communication range. Such a sub-step 111 d is referenced TX1 in figures 7 and 4. The second sub-method of step 111 can therefore advantageously comprise a sub-step 111 e (referenced TX in figures 7 and 4) of exploitation of the first communication channel in order to transmit data via said first communication channel by exploitation of the AFA technique (Automatic Frequency Agility according to English terminology).According to the invention, the downward communications TX1, TX are advantageously implemented by any node of the wireless communication network NTW of rank NR in “broadcast” mode, i.e. to all the nodes of the immediately higher rank NR+1 if the latter are obviously within radio communication range.

[0120] According to the example illustrated by Figures 4 and 7, the duration DLd is four seconds, split into two halves (two seconds each), each sub-step 111 a, 111 b, 111 d and 111 e being implemented for a quarter of the duration DLd, i.e. in this case one second or one elementary time unit TU each within the activity period T. Thus, as shown in Figure 7, sub-step 111 a is triggered immediately upon implementation of step 111. Sub-step 111 b is implemented at time t+DLd / 4, sub-step 111 d at time t+DLd / 2 and finally sub-step 111 e at time t+3DLd / 4.

[0121] As shown in Figure 4, the NTW network, when it is configured to operate according to an activity period of T of twenty seconds subdivided into twenty elementary time units TU, can comprise a large number of nodes (we will return to this later). On the other hand, it can only comprise nine hops at most. Thus, the maximum rank NRmax of a node of said NTW network is NRmax=9. The invention thus provides that sub-steps 111d and 111e are only executed if (situation illustrated by link 111 cy) said first electronic object is of a rank lower than said maximum rank NRmax within the NTW network. If not (situation illustrated by link 111 cn), said sub-steps 111d and 111e can be advantageously replaced by sub-steps 111f and 111g of closing said first communication channel as an energy-saving measure.The invention would not be limited to this single example of configuration of the NTW wireless communication network, limiting the latter to nine hops. For example, by granting a lower reactivity, an activity period T of thirty-two seconds, would allow, for a duration DLd maintained at four seconds, to authorize a maximum number of fifteen hops.

[0122] Said step 111 has also been described according to an exemplary implementation for which the duration DLd is split into two equal parts to respectively receive and transmit data according to the TDD technique, said halves of the duration DLd themselves each being split into two halves to exploit or not the AFA technique. The invention cannot be limited to this single exemplary implementation. Other duration values ​​for dividing DLd could instead be used, for example an activity period T of thirty seconds and a duration DLd of eight seconds, limiting the network to four hops.

[0123] As shown in Figure 5, the implementation of phase Ph1 is systematic. When during an activity period T, there is no downlink communication DL, the invention provides that sub-steps 111 d and 111 e are replaced by sub-steps of closing the first communication channel selected for such downlink communication DL, like sub-steps 111 f and 111 g. The elementary time units TU concerned by such a situation are shown hatched and bear the word "OFF" to indicate such a closing of the channel in Figure 5. Said time units are not used for implementing an uplink communication UL.

[0124] On this subject, let us now study step 122 of a method for managing communication channels 100 in accordance with the invention, in connection with FIGS. 4 and 8. This step 122 corresponds to the triggering and execution of an upward communication flow UL during the remainder ULd of the activity period T, i.e. immediately at the end of the downward communication phase Ph1, if no time shift A2 is provided.

[0125] Such a step 122 consists of selecting and operating a second communication channel (or a frequency band) distinct from the first channel dedicated to downlink communications DL. According to the example illustrated by FIG. 4, this uplink communication extends (duration ULd) over sixteen elementary time units TU within an activity period T of twenty seconds.

[0126] Figure 8 illustrates such an upward communication UL from the instant t of the triggering of the implementation of step 122 as well as at the discretion of the subsequent elementary time units TU, that is to say at times t+TU, up to t+T-DLd, modulo the number TUn of elementary time units TU within the activity period T. According to the rank NR of any first electronic object implementing the method 100, the time unit TU at the instant t is, in the example illustrated by Figure 4, TU4 for a node of rank NR=1, TU6 for a node of rank NR=2, ... TU18 for a node of rank NR=8, when the period T=20s and A1 and A2 (optional time offsets) are null.

[0127] The sub-steps 122a to 122n+2 (n=14 in the example of FIG. 4) correspond to steps of RXO receptions and / or TXO upward transmissions of data, steps implemented by the processing unit 11 of the first electronic object of rank NR within the NTW network and implementing the communication channel management method 100 according to the invention. Such a UL communication is done in unicast mode, that is to say to a second determined electronic object and of a rank immediately lower NR-1 than the rank NR of said first electronic object. It will be described later how said first electronic object can designate said second electronic object as the sole recipient.

[0128] If the first electronic object of rank NR implementing said method 100 (and therefore said step 122) does not have data to transmit, the second selected communication channel remains dedicated to listening to any messages sent by a third electronic object of immediately higher rank NR+1. Such an upward communication UL consisting of listening to and receiving RXO a message sent by a third electronic object of immediately higher rank NR+1 and / or consisting of transmitting TXO all or part of such data received, or even other data generated by the first electronic object, in this case the sub-steps 122c to 122n in FIG. 8, are illustrated by step blocks bearing the word "TXO / RXO" in said FIG. 8. In FIG. 4, said time units are represented by white blocks comprising a vertical arrow pointing upwards.

[0129] As shown in Figure 8, step 122 of opening the second communication channel consists of operating the second communication channel by implementing:

[0130] - a first sub-method (sub-steps 122a and 122b) for selecting said second communication channel so that it is distinct from the first communication, listening and transmission channel (TXO) by said second communication channel of a message intended for a second electronic object of the set of electronic objects forming the communication network NTW of rank immediately lower NR-1 than the rank NR of the first electronic object, when such a message has been previously developed;

[0131] - a second sub-method (sub-steps 122c to 122n): o listening and receiving (RXO) any message sent by third electronic objects of the set of electronic objects forming the NTW communication network of rank immediately higher NR+1 than the rank NR of the first electronic object, said message being addressed to said first electronic object and, o transmitting (TXO) by said second communication channel a message to a second electronic object of the set of electronic objects forming the NTW communication network of rank immediately lower NR-1 than the rank NR of the first electronic object, when such a message has been previously prepared;

[0132] - a third sub-process (sub-steps 122n+1 and 122n+2) of listening to and receiving (RXO) any message sent by third electronic objects of the set of electronic objects forming the NTW communication network of rank immediately higher NR+1 than the rank NR of the first electronic object, said message being addressed to said first electronic object.

[0133] The sub-steps 122a to 122b of the first sub-method of step 122 are illustrated by step blocks bearing the word “TXO” in said figure 8 which correspond to elementary time units TU during which the second communication channel is open to carry out only uplink transmissions TXO. In figure 4, the elementary time units TU associated with said sub-steps 122a and 122b are represented by white blocks bearing the word “TXO” associated with a vertical arrow pointing upwards. Indeed, said sub-steps 122a and 122b are dedicated to an exploitation of the second communication channel to transmit a message to a second electronic object of immediately lower rank NR-1.There is no need for the first electronic object of rank NR to implement listening on the second communication channel since any third electronic object of immediately higher rank NR+1 is busy with a downward communication DL. The latter cannot therefore send any message according to an upward communication.

[0134] The sub-steps 122n+1 and 122n+2 of the third sub-method of step 122 are dedicated to using the second communication channel to listen to and receive any messages from a third electronic object of immediately higher rank NR+1. Indeed, sending a message to a second electronic object of immediately lower rank NR-1 would be inept because the latter could not use said second communication channel to listen to and receive any message according to an upward communication since said second electronic object is busy at these times in a downward communication phase DL. In Figure 4, the elementary time units TU associated with said sub-steps 122n+1 and 122n+2 are represented by white blocks containing the word "RXO" associated with a vertical arrow pointing upwards.

[0135] Like step 111 described in connection with FIG. 7, step 122 can advantageously be arranged to prevent any unnecessary energy expenditure, in particular when the electronic object which implements a method 100 occupies the maximum rank NRmax supported by the NTW communication network. In this case, (situation illustrated by the link 122v-n in FIG. 8), the sub-steps 122c to 122n of the second sub-method of step 122 can be dedicated to simple TXO transmissions and not to RXO reception and / or TXO transmission phases because such a first electronic object of rank NRmax cannot receive a message via an ascending channel sent from an electronic object of higher rank. It would therefore be inept to listen to said second communication channel with a view to receiving a message sent from an electronic object of an immediately higher rank.Said sub-steps 122c to 122n are then illustrated by step blocks bearing the word “TXO” in said figure 8. In figure 4, said time units are represented by white blocks comprising a vertical arrow pointing upwards associated with the word “TXO”.

[0136] For the same reasons (situation illustrated by the link 122w-n in FIG. 8), step 122 can be arranged so that sub-steps 122n+1 to 122n+2 can consist of closing the operation of the second communication channel in place of RXO reception sub-steps for any other first electronic object of lower NR ranks. Said sub-steps 122n+1 to 122n+2 are then illustrated in said FIG. 8, by step blocks bearing the crossed-out word “UL”. In FIG. 4, said elementary time units TU associated with such sub-steps 122n+1 to 122n+2 are represented by blocks comprising hatching and the word “OFF”.

[0137] More synthetically, it is therefore advantageous to provide that the second and third sub-methods of step 122 of opening the second communication channel consisting of listening and receiving (RXO) any message sent by third electronic objects of the set of electronic objects forming the communication network NTW of rank immediately higher NR+1 than the rank NR of the first electronic object, said message being addressed to said first electronic object, can be implemented if and only if (situation illustrated by the link 122v-y in figure 8) the value of the rank NR of the first electronic object is strictly lower than the predetermined value NRmax.

[0138] Furthermore, the invention provides that an ascending UL communication consisting of listening and receiving RXO a message sent by an electronic object of immediately higher rank NR+1 and / or consisting of transmitting TXO all or part of such received data, or even other generated data to an electronic object of immediately lower rank NR-1, are advantageously implemented according to the CSMA / CA protocol as mentioned above. Thus, during an ascending UL communication, any electronic object arranged according to the invention listens periodically and briefly to the second communication channel and switches to transmission on it punctually if it has a message to transmit. Otherwise, only the RXO listening phase is implemented.The invention can rely for this on the ultra-low consumption WoR mechanism (“Wake on Radio” according to English terminology) allowing, by the exploitation of a long beacon preamble, that is to say greater than the listening period, to obtain a low energy cost for RXO listening compared to that of TXO transmission.

[0139] Unlike said upward communication UL, a downward communication DL according to the invention requires a minimum of synchronization between the different electronic objects of the assembly forming a multi-hop wireless communication network NTW. However, the drift of the internal clocks, generally quartz clocks, of the processing units 11 of such electronic objects forming an NTW network according to the invention is low, of the order of + / -180ms over one hour. Such synchronization of all the electronic objects to “align” the activity periods T does not require a high frequency.Figure 9 describes a synchronization service in the form of an iterative processing 200 for parameterizing the implementation of a communication channel management method 100 already mentioned in connection with Figure 6, implemented by the processing unit 11 of any first electronic object belonging to a set of electronic objects forming a wireless communication network NTW according to the invention. The implementation of such processing 200 is triggered in a step 201 of detecting the reception of a specific BEAT-Mg message that can be discriminated among the other messages circulating within said NTW network by the first communication channel dedicated to downlink communication DL orchestrated by the implementation of said method 100.Such a BEAT-Mg message is initially developed and sent according to a downward communication DL by the concentrator / gateway device CG arbitrating said NTW network to all the electronic objects forming said NTW network.

[0140] According to the invention, such a BEAT-Mg message conveys the rank of its transmitter. If we consider the very first electronic object Ni of the assembly forming a communication network according to the invention, the latter must reset its rank NR within the NTW network upon receipt of such a BEAT-Mg message. Such a transmitter of a BEAT-Mg message may be the concentrator / gateway device CG which occupies rank 0 within the NTW network or a second electronic object of rank higher than the zero rank of the concentrator / gateway device CG. Said step 201 of the processing 200 further consists of reading said BEAT-Mg message to determine the necessarily immediately lower rank of its transmitter with respect to that NR of said first electronic object.

[0141] Said processing 200 comprises a step 202 of calculating the value of the rank NR of said first electronic object consisting of incrementing by one unit the value of the rank (NR-1) of the transmitter of the BEAT-Mg message read in step 201. This value NR can advantageously be recorded in the data memory 12 of said first electronic object Ni.

[0142] The processing 200 further comprises a step 203 of triggering the initialization of the internal clock in the processing unit 11 of the first electronic object Ni and therefore of the activity period T. Such a processing 200 further comprises a step 205 of relaying a BEAT-Mg message to any third object located within radio communication range and listening to a transmission on said first communication channel dedicated to downlink communication DL. Such a step 205 consists of preparing a new BEAT-Mg message conveying the value NR of the rank of said first electronic object and causing the transmission TX1 or TX of said relayed BEAT-Mg message via the first communication channel dedicated to downlink communication DL.

[0143] Thus, upon receipt of such a BEAT-Mg message relayed on the first communication channel, any third electronic object may in turn determine by incrementation its rank NR+1 within the network by incrementing by one unit the rank of the object transmitting said relayed BEAT-mg message.

[0144] For the sake of energy saving, the invention provides that step 205 can only be implemented (situation illustrated by link 204-y in FIG. 9) if the first electronic object does not occupy the maximum rank NRmax supported by the NTW communication network. The value of such a maximum rank NRmax can be predetermined by construction and thus be fixed. The same applies to the activity period T, the number TUn of subdivisions TU in the form of elementary time units of said activity period T, the duration DLd of the phase Ph1, the time offsets A1 and A2, etc. Alternatively, all or part of these values ​​can constitute parameters for implementing the method for managing the communication channels of all the electronic objects forming an NTW communication network.The same applies to a PNI (Private Network Identifier in English terminology) or any other attribute characterizing the belonging of an electronic object to a specific family of nodes forming an NTW network as mentioned previously.According to this advantageous variant making it possible to dynamically parameterize the operation of the network for transmitting a BEAT-MG ​​message, such a message can convey, in addition to the rank of its transmitter, one or more parameters p for implementing said method 100 from a set of parameters comprising, in a non-exhaustive manner, the activity period T, the number Tlln of elementary time units of said activity period T, the first duration DLd of implementation of the steps of opening 111 of the first communication channel and closing 112 of the second communication channel mutually constituting an exclusive downlink communication phase Ph1, the value of the maximum rank NRmax supported by the communication network NTW, the first and / or second time offsets A1 and A2, etc.

[0145] In this case, step 201 of reading said BEAT-Mg message further consists of reading the value of said parameter(s) p for implementing said method 100 and recording in a data memory 12 of the first electronic object the value(s) of said parameter(s) p. To take into account such a parameter p (which may therefore be plural), a method 100 according to the invention comprises a step 101 for reading the value of said parameter p in the data memory 12 and for configuring the implementation of said method 100 on the basis of said value of the parameter p read. To propagate the value of said parameter p, step 205 of relaying a BEAT-Mg message consists of developing a new BEAT-Mg message conveying the value NR of the rank of said first electronic object and that of the parameter p for implementing said method 100.

[0146] The upward communication UL via the second communication channel is advantageously done in unicast mode, that is to say to a second determined electronic object and of a rank immediately lower NR-1 than the rank NR of said first electronic object. So that the latter can address a message to only the second electronic object, the invention provides that a BEAT-Mg message can also include the unique identifier of the transmitting electronic object. Thus, the steps 201 of reading such a BEAT-Mg message can be arranged to read this identifier and record the latter like any operating parameter p in the data memory 12 of the first electronic object receiving a BEAT-Mg message. Furthermore, the step 205 of relaying a BEAT-Mg message can consist of developing a new BEAT-Mg message also conveying the identifier IDi of the first electronic object to teach the third objects of higher rank.Any alternative technique could be implemented to inform any first electronic object drawn from the set of electronic objects forming an NTW network in accordance with the invention as to the unambiguous designation of a second electronic object of lower rank.

[0147] The nodes of known wireless communication networks such as the NTW network according to figure 1 of so-called "star" topology like LoRaWAN have various energy consumption points depending on the geographical distance or the environment separating them from the gateway G. Thus, the geographically most distant objects necessarily exploit a higher transmission power compared to that exploited for the nodes close to the gateway. The multi-hop topology of an NTW communication network according to the invention drastically limits the energy consumption of the nodes of an NTW network as presented by figure 3 compared to a star topology network, since the transmission power used by each node to communicate with the device CG is shared by the exploitation of relay nodes.However, such a multi-hop topology can induce a phenomenon known as the "tunnel effect" or "funneling effect". At constant transmission power, this phenomenon results from the relay activity conducted by any node of said network, except for the nodes occupying the maximum rank NRmax. As shown in Figure 3, it is easy to understand that there will always be more high-ranking objects than low-ranking objects. Thus, naturally, low-ranking electronic objects, i.e. those closest to the concentrator / gateway device CG, are more solicited to conduct the relay activity than their higher-ranking peers. To limit the impact of this tunnel effect, the invention provides an advantageous embodiment described in Figure 10.A method 100 according to the invention can thus use a technique that we can call "aggregation technique" on the uplink UL and downlink DL flows via the first and second communication channels. In this way, instead of sending a plurality of short messages on such a flow, the invention makes it possible to aggregate said plurality in the form of a single message or a smaller number of messages. It is thus possible, as mentioned previously, to share the energy cost of the long preamble of any uplink TXO or downlink TX1 / TX transmission. In addition to optimized energy consumption, this advantageous technique makes it possible to maximize the net useful throughput of the communication and prevents the risk of saturation of a relay node, which without the use of such a variant could no longer be able to evacuate messages faster than it receives them.

[0148] Thus, figure 10 describes an aggregation service or processing 300 implemented by the processing unit 11 of any first electronic object, such as the node Ni according to figure 2, taken from a set of electronic objects forming a plurality of nodes of a communication network according to the invention such as the NTW network described in connection with figure 3.

[0149] Thus, such a data aggregation processing 300 is implemented before any transmission TX1, TX according to the first communication channel dedicated to a downlink communication DL. Such an aggregation processing comprises a step 301 of detecting the reception RX1, RX, via the first communication channel, of an incoming message IN-Mg emanating from a second electronic object of a rank immediately lower than the rank NR of said first electronic object receiving said message. Said step 301 further consists of reading said incoming message IN-Mg and developing, from all or part of the data drawn from said incoming message, data to be transmitted to a third electronic object of a rank immediately higher than the rank of said first electronic object, if such a third object has the capacity to listen to and receive an incoming message via said first communication channel dedicated to a downlink communication DL.To combat the tunnel effect, such processing 300 comprises a step 303 of aggregating all data intended for such a third electronic object so as to form an outgoing message OUT-Mg of a size greater than or equal to (situation illustrated by the link 304-n in FIG. 10) a predetermined minimum threshold Ls. Such a step 303 is thus iterated as long as (situation illustrated by the link 304-y in FIG. 10) the useful data D to be transmitted would be a payload of an outgoing message of a size less than said threshold Ls. When such a threshold Ls is reached or exceeded (situation illustrated by the link 304-n in FIG. 10), an outgoing message OUT-Mg can be prepared to be transmitted to any third electronic object.However, the transmission as such, in this case in the form of a step 306 of triggering the transmission TX1, TX of said outgoing message OUT-Mg can only be implemented if (situation illustrated by the link 305-y in FIG. 10) said first communication channel is open (see phase Ph1 of the method 100). Said processing 300 can therefore comprise a step 305 of waiting for the opening of said first communication channel as long as (situation illustrated by the link 305-n in FIG. 10) it is closed.

[0150] Such data to be transmitted in the form of an outgoing message OUT-Mg may also result from a process independent of any prior reception of an incoming message. The processing 300 may thus include a step 302 of producing data exogenous to any incoming message. Such data may be the result of measurements of the immediate environment of said first electronic object, if the latter comprises or is linked to one or more measurement sensors. They may alternatively reflect an operating alert of said electronic object resulting for example from an electric battery level necessary for its operation when said level becomes lower than a predetermined threshold.

[0151] For reasons of saving such energy resources, the invention provides that such aggregation processing 300 is only implemented if the rank of said first electronic object is strictly lower than the maximum rank NRmax supported by the NTW communication network. Indeed, there is no need to communicate to an object of rank higher than said maximum rank NRmax.

[0152] The same aggregation processing 300 can be implemented to optimize the UL uplink communications from any first electronic object taken from a set of objects forming an NTW network according to the invention. Thus, such processing 300 comprises a first step 301 of detecting the RXO reception, via the second communication channel dedicated to UL uplink communication, of an incoming message IN-Mg emanating from a third electronic object of a rank immediately higher than the rank of said first electronic object receiving said message. Such a step 301 further consists of reading said incoming message IN-Mg and developing data intended for a second electronic object of a rank immediately lower than the rank of said first electronic object, if said second object has the capability of RXO listening and reception via said second communication channel dedicated to UL uplink communication.Such processing 300 comprises, like what has been mentioned in connection with a downward communication DL, a step of aggregation 303 of all data intended for such a second electronic object so as to form an outgoing message OUT-Mg of a size greater than or equal to (situation illustrated by the link 304-n in FIG. 10) a predetermined minimum threshold Ls.

[0153] Such processing 300 comprises a step 305 of waiting for the opening of said second communication channel as long as (situation illustrated by the link 305-n in FIG. 10) it is closed, then a step of triggering the transmission TX0 of the outgoing message OUT-Mg as soon as (situation illustrated by the link 305-y in FIG. 10) said second communication channel is open.

[0154] Such data to be transmitted to a second electronic object of a rank immediately lower than the rank NG of said first electronic object, may also result from a step 302 of producing data exogenous to any incoming message received via said second communication channel.

Claims

CLAIMS 1. Method (100) for managing communication channels to ensure low-speed wireless communication over long distances, respectively uplink (UL) to a hub / gateway device (CG) and downlink (DL) from said hub / gateway device (CG), said method (100) being arranged to be implemented iteratively according to a predetermined activity period (T), by a processing unit specific to any first electronic object belonging to a set of electronic objects forming a multi-hop communication network (NTW) arbitrated by said hub / gateway device (CG) and comprising: - steps of opening (111) and closing (121) a first communication channel dedicated to downlink communication (DL); - steps of opening (122) and closing (112) a second communication channel dedicated to upward communication (UL), said first and second communication channels being distinct; said method (100) being characterized in that the activity period (T) is subdivided into a predetermined number TUn of elementary time units and in that: - the steps of opening (111) the first communication channel and closing (112) the second communication channel, mutually constituting an exclusive downward communication phase (Ph1), are triggered during a first elementary time unit (TU) within the activity period (T) whose index t1 is a function of the rank (NR) of said first electronic object (Ni) and implemented for a first predetermined duration (DLd); - the steps of closing (121) the first communication channel and opening (122) the second communication channel mutually constituting an exclusive phase (Ph2) of ascending communication (UL), are triggered during a second elementary time unit (TU) within the activity period (T) whose index t2 is also a function of the rank (NR) of said first electronic object and implemented for a second determined duration (ULd), the sum of said first and second durations (DLd, ULd) not exceeding the activity period (T).

2. Method (100) according to the preceding claim, for which: - the value of the index t1 is between 0 and TUn-1 and is determined by the operation t1 = [A1 + (NR-1 ) * DLd / 2] modulo T, DLd being the first predetermined duration (DLd) of implementation of the exclusive downlink communication phase (Ph1 ), NR being the rank of said first electronic object (Ni) within the communication network (NTW) in the form of a strictly positive integer value and less than or equal to a predetermined maximum rank value NRmax, A1 being a first time offset in the form of a predetermined integer number of elementary time units (TU) greater than or equal to zero; - the value of the index t2 is between 0 and TUn-1 and is determined by the operation t2=[A1 +(NR+1)*DLd / 2+A2] modulo T, A2 being a second time shift in the form of a predetermined integer number of elementary time units (TU) greater than or equal to zero.

3. Method (100) according to the preceding claim, for which: - the predetermined values ​​of said first and second time shifts A1 and A2 are zero; - the predetermined value of the activity period T is equal to twenty seconds, said activity period T comprising a number Tlln equal to twenty elementary time units of one second each; - the predetermined value of the first duration DLd is equal to four seconds; - the predetermined value of the maximum rank NRmax of an electronic object part of the communication network (NTW) is equal to nine.

4. Method (100) according to any one of the preceding claims, for which the step (111) of opening the first communication channel consists of operating, according to a technique called “duplex by time separation”, the first communication channel by implementing: - a first sub-method (111a, 111b, RX1, RX) for selecting said first communication channel, listening to and receiving any message sent by a second electronic object of the set of electronic objects forming the communication network (NTW) of rank immediately lower than the rank NR of the first electronic object; - a second sub-process (111 d, 111 e, TX1, TX) for transmitting by said first communication channel a message to all third electronic objects, the set of electronic objects forming the network of communication (NTW) of rank immediately higher than the NR rank of the first electronic object.

5. Method (100) according to the preceding claim, for which said second sub-method (111 d, 111 e, TX1, TX) of transmission by said first communication channel of a message to all third electronic objects of the set of electronic objects forming the communication network (NTW) is only implemented if (111 cn) the rank NR of the first electronic object is strictly lower than the maximum rank NRmax of said network (NTW).

6. Method (100) according to any one of claims 4 and 5, for which said first and second sub-methods are implemented one after the other, each for a duration equal to half of the first duration DLd.

7. Method (100) according to any one of the preceding claims, for which the step (122) of opening the second communication channel consists of operating the second communication channel by implementing: - a first sub-method (122a, 122b, RX0) for selecting said second communication channel so that it is distinct from the first communication, listening and transmission channel (TX0) by said second communication channel of a message intended for a second electronic object of the set of electronic objects forming the communication network (NTW) of rank immediately lower than the rank NR of the first electronic object, when such a message has been previously developed; - a second sub-method (122c, 122n, TX0 / RX0): o listening and receiving (RXO) any message sent by third electronic objects of the set of electronic objects forming the communication network (NTW) of rank immediately higher than the NR rank of the first electronic object, said message being addressed to said first electronic object and, o transmitting (TXO) by said second communication channel a message to a second electronic object of the set of electronic objects forming the communication network (NTW) of rank immediately lower than the NR rank of the first electronic object, when such a message has been previously prepared; - a third sub-process (122n+1, 122n+2, RXO) for listening to and receiving (RXO) any message sent by third electronic objects of the set of electronic objects forming the communication network (NTW) of rank immediately higher than the rank NR of the first electronic object, said message being addressed to said first electronic object.

8. Method (100) according to the preceding claim when the latter depends on claim 2, for which the second and third sub-methods of the step (122) of opening the second communication channel consist of listening to and receiving (RXO) any message sent by third electronic objects of the set of electronic objects forming the communication network (NTW) of rank immediately higher than the rank NR of the first electronic object, said message being addressed to said first object electronic if and only if (122v-y) the value of the rank NR of the first electronic object is strictly less than the predetermined NRmax value.

9. Method (100) according to any one of the preceding claims, comprising a processing (200) for parameterizing the implementation of said method (100), said processing (200) comprising: - a step (201) of detecting the reception of a BEAT-Mg message discriminable among all other messages transmitted via the first communication channel dedicated to downlink communication (DL) and of reading said BEAT-Mg message to determine the rank (NR-1) of its transmitter, said BEAT-Mg message conveying said rank (NR-1) of said transmitter; - a step (202) of calculating the value of the rank NR of said first electronic object consisting of incrementing by one unit the value of the rank (NR-1) of the transmitter of the BEAT-Mg message read in the previous step (201); - a step (203) of triggering the initialization of the internal clock in the processing unit (11) of the first electronic object and therefore of the activity period (T).

10. Method (100) according to the preceding claim, comprising a step (205) of relaying a BEAT-Mg message to any third object located within radio communication range and listening to a transmission on said first communication channel dedicated to downlink communication (DL), said step (205) consisting of developing a new BEAT-Mg message conveying the NR value of the rank of said first electronic object and causing the transmission (TX1, TX) of said message via the first communication channel dedicated to downlink communication (DL).

11. Method (100) according to the preceding claim when the latter depends on claim 2, for which the step (205) of relaying a BEAT-Mg message is only implemented (204, 204-y) if the rank NR of said first electronic object is strictly lower than the predetermined maximum rank value NRmax.

12. Method (100) according to any one of claims 9 to 11 when they depend on claim 2, for which: - a BEAT-Mg message further carries a parameter (p) for implementing said method (100) from a set of parameters, said set of parameters comprising the activity period (T), the number Tlln of elementary time units of said activity period (T), the first duration of implementation of the steps of opening (111) the first communication channel and closing (112) the second communication channel mutually constituting an exclusive downlink communication phase (Ph1), the value of the maximum rank NRmax supported by the communication network (NTW), the first and / or second time offsets A1 and A2; - the step (201) of reading said BEAT-Mg message further consists of reading the value of said parameter (p) of implementation of said method (100) and recording in a data memory (12) of the first electronic object said value of said parameter (p); - said method (100) further comprises a step (101) for reading the value of said parameter (p) and configuring the implementation said method (100) on the basis of said value of the parameter (P) read.

13. Method (100) according to the preceding claim when it depends on claim 10, for which the step (205) of relaying a BEAT-Mg message consists of developing a new BEAT-Mg message conveying the NR value of the rank of said first electronic object and of the parameter (p) of implementation of said method (100).

14. Method (100) according to any one of the preceding claims, comprising a data (D) aggregation processing (300) implemented before any transmission (TX1, TX) according to the first communication channel dedicated to a downlink communication (DL), said aggregation processing (300) comprising: - a step (301) of: o detecting the reception (RX1, RX) via said first communication channel, of an incoming message (IN-Mg) emanating from a second electronic object of a rank immediately lower than the rank NR of said first electronic object receiving said message; o reading said incoming message (IN-Mg) and developing data to be transmitted to a third electronic object of a rank immediately higher than the rank of said first electronic object; - a step of aggregating (303) all data (D) intended for such a third electronic object so as to form an outgoing message (OUT-Mg) of a size greater than or equal (304-n) to a predetermined minimum threshold (Ls); - a step of waiting (305) for the opening of said first communication channel while (305-n) it is closed; - a step (306) of triggering the transmission (TX1, TX) of the outgoing message (OUT-Mg) as soon as (305-y) said first communication channel is open.

15. Method (100) according to the preceding claim, comprising a step (302) of producing data external to any incoming message via said first communication channel, said data produced being intended to be transmitted to any third electronic object of a rank immediately higher than the NR rank of said first electronic object.

16. Method (100) according to claim 14 or 15 when it depends on claim 2, for which said aggregation processing (300) is only implemented if the rank of said first electronic object is strictly lower than the maximum nd NRmax supported by the communication network (NTW).

17. Method (100) according to any one of the preceding claims, comprising a data aggregation processing (300) implemented before any transmission (TX0) according to the second communication channel dedicated to an upward communication (UL), said aggregation processing comprising: - a step (301) of: o detecting the reception (RX0) via the second communication channel, of an incoming message (IN-Mg) emanating from a third electronic object of a rank immediately higher than the rank of said first electronic object receiving said message; o reading of said incoming message (IN-Mg) and processing of data (D) to be transmitted to a second electronic object of a rank immediately lower than the rank of said first electronic object; - a step of aggregating (303) all data (D) intended for such a second electronic object so as to form an outgoing message (OUT-Mg) of a size greater than or equal (304-n) to a predetermined minimum threshold (Ls); - a step of waiting (305) for the opening of said second communication channel while (305-n) it is closed; - a step of triggering (306) the transmission (TXO) of the outgoing message (OUT-Mg) as soon as (305-y) said second communication channel is open.

18. Method (100) according to the preceding claim, comprising a step (302) of producing data external to any incoming message via said second communication channel, said data produced being intended to be transmitted to a second electronic object of a rank immediately lower than the NR rank of said first electronic object.

19. Electronic object comprising: - a processing unit (11) comprising a clock; - a data memory (12); - a program memory (13); - wireless means of communication (15) with the outside world; - an electrical energy source (16) in the form of one or more batteries; said electronic object being characterized in that the processing unit (11) is arranged to implement a method for managing communication channels (100) according to any one of the preceding claims.

20. Communication network (NTW) comprising a concentrator / gateway device (CG) and a plurality of electronic objects according to the preceding claim.

21. Computer program product comprising one or more program instructions interpretable by a processing unit (11) of an electronic object according to claim 19, said program instructions being loadable into the program memory (13) of said object and designed so that the execution of said instructions by said processing unit (11) causes the implementation of a method according to any one of claims 1 to 18.

22. Computer-readable storage medium comprising the instructions of a computer program product according to the preceding claim.

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