Method and device for the automatic deployment of a communication network

Abstract

The invention relates to a device and a method for the automatic deployment of a communication network between a mobile vehicle (MV) and a rear base (RB), the mobile vehicle moving from an initial position along a trajectory T. The deployment consists of positioning a plurality of communication relay devices along the MV's trajectory to form a bidirectional, linear, meshed wireless communication network between the MV and the rear base, such that communications between the mobile vehicle and the rear base maintain a communication link quality Q equal to or greater than a threshold value S. Each communication relay device is an autonomous mobile device, called an Autonomous Robotic Communication Relay (ARCR), capable of moving autonomously and positioning itself along the trajectory T followed by the MV to maintain the communication link quality. See Fig. 2a for the abstract.

Description

Title of the invention: Method and device for automatic deployment of a communications network Field of invention

[0001] The invention is in the technical field of telecommunications networks, and more particularly relates to a method for automatically deploying a mesh wireless communication network in order to maintain wireless connectivity between a moving mission vehicle and a rear base. State of the Art

[0002] The technical problem addressed by the present invention is that of the degradation or loss of wireless connectivity between a rear base (RB) and a moving mission vehicle (VM). A distance that becomes too great between a rear base and a moving VM may no longer preserve quality connectivity between the BR and the VM when the only connection between the two objects is a direct wireless connection, for example a radio connection of the WiFi, LiFi or other transmission technology type.

[0003] In practice, such situations may arise when, for the purposes of a mission to be carried out, the VM must be required to move over a fairly large area (for example in the case of inspecting an open area outdoors) or when the VM must move in environments limiting the propagation of wireless communications (for example in highly metallic environments which restrict the propagation of the radio signal, such as a building with reinforced concrete walls or the like).

[0004] The applications are numerous, and require maintaining sufficient quality of wireless connectivity between the moving VM and its rear base, to be able to route data required by the VM's mission bidirectionally between the VM and the BA, despite the movement of the VM.

[0005] Solutions approach this problem by proposing to build a multi-hop wireless interconnection network between a rear base and a moving vehicle. Thus, the Applicant's patent application WO2015 / 086331 proposes to set up communication relay nodes between the BA and the VM as the VM moves. The communication relays constituting the relay nodes of the multi-hop network between the VM and the BA are communicating objects transported by the VM, the latter being able to deploy them, i.e. place them on the ground, when necessary. The disadvantage of this solution is that it requires a hardware adaptation of the VM which must transport the relays to ensure their deployment. deployment. Furthermore, communicating objects deployed by the VM do not have the ability to adapt their location once deposited.

[0006] Also, there is a need for a solution that overcomes the drawbacks of known solutions and that makes it possible to maintain quality wireless connectivity between a Rear Base (RB) and a Mission Vehicle (MV) on the move, without restricting the VM's movement capabilities.

[0007] The present invention meets these needs. Summary of the invention

[0008] An object of the present invention is a method for automatically deploying a telecommunications network, with a view to maintaining wireless connectivity between a moving mission vehicle (VM) and a rear base (BA).

[0009] Generally speaking, the invention is based on a set of equipment called “Autonomous Robotic Communication Relay” (RCRA), each equipment being capable of moving autonomously along a trajectory followed by a VM and a set of equipment deployed along the trajectory of the VM forming a linear mesh wireless communication network (or “mesh” in English or multi-hop), between the VM and the rear base.

[0010] Advantageously, the method of the invention makes it possible to automatically control the positioning of each RCRA along the trajectory of a VM, as well as the addition, if necessary, of any new RCRA, so as to preserve the wireless connectivity between the VM and the BA, and to ensure that the connectivity is of sufficient quality to route bidirectionally between the VM and the BA, the data required within the framework of the mission of the VM, despite the movement of the VM.

[0011] Advantageously, the method of the invention allows a VM, via the automatic deployment of RCRAs along its trajectory, to remain connected to a BA even if direct connectivity between the VM and the BA is lost (for example, at the limit of radio signal coverage).

[0012] Thus, thanks to the method of the invention, a VM can travel greater distances or penetrate more hostile environments, such as highly metallic environments which constrain the propagation of the radio signal, while preserving quality connectivity with a BA for data transmission.

[0013] In one embodiment, the invention comprises a so-called fallback mode which allows, when a VM turns back along its initial trajectory, an automatic fallback of the RCRAs which have been deployed along this same trajectory, and a progressive dismantling of the mesh network formed by the deployed RCRAs, as the RCRAs are withdrawn from the mesh network as soon as they are no longer necessary for preserve quality connectivity between the VM and a BA.

[0014] The fallback mode is particularly advantageous because it makes it possible to limit the number of RCRAs to be deployed in order to allow a VM to return to its initial point at the end of the mission (typically it makes it possible to halve this number compared to a configuration without fallback mode).

[0015] Furthermore, the fallback mode is particularly interesting when a VM is circulating in an extremely confined environment (for example a corridor) which does not physically allow a VM and an RCRA to cross paths.

[0016] Advantageously, the present invention does not require any adaptation of a VM to ensure the deployment of RCRA relay nodes, these relay nodes being robotic equipment capable of moving autonomously in the environment. In addition, the mobile robotic relay nodes (RCRAs) automatically adapt their location when the VM moves in order to preserve quality connectivity between the VM and the BA.

[0017] Advantageously, the device of the invention does not require any hardware adaptation of the VM, its implementation is greatly facilitated as well as its applicability to any type of application scenario. An implementation of the invention can be in the form of a generic wireless connectivity extension system capable of interfacing simply and very quickly with any type of VM.

[0018] The fields of industrial application of the invention are multiple and cover without limitation solutions for inspection, surveillance, robotic intervention for security, defense, first aid needs, or more specific industrial needs such as for example nuclear dismantling.

[0019] To obtain the desired results, a method is proposed for automatically deploying a communication network between a mobile vehicle VM and a rear base BA, the mobile vehicle moving from an initial position along a trajectory T, the deployment consisting of positioning a plurality of communication relay devices along the trajectory of the VM to form between the VM and the rear base a bidirectional, linear wireless mesh communication network, such that the communications between the mobile vehicle and the rear base have a communication link quality Q equal to or greater than a threshold value S, each communication relay device being an autonomous mobile device called an Autonomous Robotic Communication Relay RCRA, capable of moving autonomously and positioning itself along the trajectory T followed by the VM, the method comprising steps consisting of:

[0020] (a) determining when the quality of communication link between the rear base and a last RCRA(N) communication relay positioned on trajectory T, is lower than the threshold value S, said RCRA(N) being considered as the Father of the base back BA such that Father(BA) = N;

[0021] (b) position a new RCRA(N+1) communication relay along the tra jectory T, between the rear base BA and the last communication relay RCRA(N), the position of the new communication relay RCRA(N+1) being determined to establish a quality of communication link between the RCRA(N+1) and the BA at a value equal to or greater than the threshold value S;

[0022] (c) configure the network's RCRAs communication relays positioned on the tra jectory T, the rear base BA and the mobile vehicle VM, to define that the new communication relay RCRA(N+1) becomes the Father of the BA such that Father(BA) = (N+1) and define that the linear wireless mesh network between the VM and the rear base BA is updated with the addition of the new communication relay RCRA(N+1) positioned between the BA and the RCRAN; and

[0023] (d) repeat steps (a) to (c).

[0024] According to alternative or combined embodiments:

[0025] - the step of positioning a new RCRA(N+1) communication relay comprises a first step consisting of activating the movement of the new RCRA(N+1) communication relay from a reserve zone to the initial position of the trajectory T, the reserve zone grouping together a plurality of communication relays.

[0026] - the step of configuring the RCRAs communication relays of the network positioned on trajectory T, includes configuration steps for the new RCRA(N+1) communication relay consisting of:

[0027] - reconfigure a routing table (406) of the RCRA(N+1) to indicate that the RCRA(N) is directly reachable and is the next relay to reach all other RCRAs in the network and the VM;

[0028] - identify that the Father of the RCRA(N+1) is the RCRA(N), and (708-3) that the Son of the RCRA(N+1) is the BA;

[0029] - activate a module (414) for receiving the trajectory T of the VM from the RCRA(N)

[0030] - activate a module (416) for transmitting the trajectory of the VM towards the BA; and

[0031] - activate a module (418) for monitoring the quality of the direct link with its Father the RCRA(N).

[0032] - the step of configuring the network communication relays positioned on the trajectory T, includes steps for configuring the last RCRA(N) communication relay positioned on trajectory T, consisting of:

[0033] - reconfigure a routing table (406) of the RCRA(N) to indicate that the RCRA(N+1) can be reached directly and the BA can be reached via the new RCRA(N+1) communication relay;

[0034] - identify that the Son of the RCRA(N) is the RCRA(N+1); and

[0035] - reconfigure a VM trajectory transmission module (416) to activate the transmission of the trajectory to the new RCRA(N+1) Son of the RCRA(N).

[0036] - the step of configuring the rear base BA, comprises steps consisting of:

[0037] - add the new RCRA(N+1) communication relay to a list 'L' of RCRAs integrated into the linear wireless mesh network;

[0038] - reconfigure a routing table (306) of the BA to indicate that all RCRAs included in list 'L', other than the new RCRA(N+1) communication relay, are reachable via the new RCRA(N+1) communication relay, and that the mobile vehicle VM is reachable via the new RCRA(N+1) communication relay;

[0039] - identify that the BA rear base father is the new communication relay RCRA(N+1); and

[0040] - configure a module (310) for receiving the VM trajectory to activate the reception of the trajectory from the new RCRA Father (N+1).

[0041] - the configuration step of the new RCRA(N+1) communication relay further includes a step consisting of transmitting the entire trajectory T of VM to the new communication relay.

[0042] - the step of configuring the RCRA communication relays of the wireless network linear mesh, also includes steps allowing each relay positioned along the trajectory T of the VM to:

[0043] - monitor the quality of the communication link between him and his Father; and

[0044] - advance autonomously on the trajectory T when the quality of the link is in lower than the threshold value S.

[0045] - the monitoring step further comprises a step of monitoring the distance between him and his Father, and the advancement step consists of advancing when the quality of the link is lower than the threshold value S and the distance between him and his Father is greater than a safety distance ds.

[0046] - the method further comprises a step consisting of calculating a new value S of the quality threshold before the configuration step.

[0047] - the method further comprises steps allowing a progressive and automation of communication relays positioned on the trajectory T of the mobile vehicle VM, when a VM turns back along its initial trajectory, the withdrawal of the communication relays leading to a dismantling of the linear mesh wireless network.

[0048] The invention also relates to a device for the automatic deployment of a communication network between a mobile vehicle VM and a rear base BA, the mobile vehicle moving from an initial position along a trajectory T, the deployment consisting of positioning a plurality of communication relay equipment communication along the trajectory of the VM to form between the VM and the rear base a bidirectional, linear wireless mesh communication network, such that the communications between the mobile vehicle and the rear base have a communication link quality Q equal to or greater than a threshold value S, each communication relay equipment being an autonomous mobile equipment called Autonomous Robotic Communication Relay RCRA, capable of moving autonomously and positioning itself along the trajectory T followed by the VM, the device comprising means for implementing the steps of the method of the invention.

[0049] According to alternative embodiments of the device of the invention, the mobile vehicle is a land or air or amphibious or aquatic vehicle, said vehicle being piloted or remotely piloted or self-piloted.

[0050] In an advantageous embodiment, the bidirectional, linear wireless mesh communication network is implemented according to an SDN “Software Defined Networking” oriented architecture comprising an SDN controller having a North Interface and a South Interface, set up at the rear base BA. The SDN controller is able to control via its South Interface the configurations of SDN equipment constituted by the BA, the VM and all the RCRAs, and able to implement in the form of an SDN Service via its North Interface the steps of the method of the invention.

[0051] The invention also relates to a computer program product which comprises code instructions making it possible to carry out the steps of the method of the invention, when the program is executed on a computer. Description of figures

[0052] Other characteristics and advantages of the invention will appear with the aid of the following description and the figures of the appended drawings in which:

[0053] [Fig.l] illustrates different examples of application context of the invention, implementing communication between a Mission Vehicle (VM) and a Rear Base (BA);

[0054] [Fig.2a] illustrates a set of RCRAs deployed on the trajectory of a VM in one embodiment;

[0055] [Fig.2b] illustrates the addition of an RCRA to the linear mesh wireless communication network between the BA and the VM of [Fig.2a];

[0056] [Fig.3] illustrates the main functional characteristics of a rear base (BA) in one embodiment;

[0057] [Fig.4] illustrates the main functional characteristics of an autonomous robotic communication relay (ARCR) in one embodiment;

[0058] [Fig.5] illustrates the main functional characteristics of a mission vehicle (MV) in one embodiment;

[0059] [Fig.6a] is a flowchart of the steps performed by an RCRA integrated into a linear wireless mesh communication network between a BA and a VM;

[0060] [Fig.6b] is a flowchart of a variant of the method of [Fig.6a];

[0061] [Fig.7] is a flowchart of the steps taken by a BA to integrate a new RCRA into a linear mesh wireless communication network between a BA and a VM;

[0062] [Fig.8a] and [Fig.8b] are flowcharts detailing steps of the method of [Fig.7];

[0063] [Fig.9] is a flowchart of the steps performed by an RCRA in fallback mode; and

[0064] [Fig. 10a] and [Fig. 10b] are flowcharts detailing steps carried out by a BA to dismantle a network of RCRAs in fallback mode. Detailed description of the invention

[0065] [Fig.l] illustrates different examples of application context of the invention, implementing communication between a Mission Vehicle (VM) and a Rear Base (BA).

[0066] In the context of the invention, the expression “mission vehicle” (VM) is to be taken in its broadest sense and can designate any mobile machine, whether it be a land vehicle (102), maritime vehicle (104, 106), air vehicle (108), a civil or military vehicle, etc., which moves to carry out a mission.

[0067] A mission carried out by a VM can be without limitation:

[0068] - a rescue mission: such as the inspection of an area which has suffered an incident (for example a fire, a flood, an earthquake...), the search for and location of victims...;

[0069] - a security mission: such as the surveillance of an area (for example a border...), the detection and localization of security alerts (for example, unauthorized entries into an area...);

[0070] - an industrial mission: such as taking charge of the dismantling of an ins critical facility (e.g. a nuclear site); or

[0071] - any other type of mission.

[0072] Furthermore, a vehicle in the context of the invention may be a vehicle piloted by a person (104, 106) or remotely operated (108) or even an autonomous vehicle (102) capable of moving alone in its environment according to a mission objective (for example following a predefined trajectory in a given area).

[0073] Thus without limitation, a VM can be:

[0074] - a flying vehicle such as a drone (remotely operated or autonomous), an airplane, etc.;

[0075] - a land vehicle, whatever its mode of locomotion (for example equipped with wheels, tracks, etc.), such as a mobile inspection robot, etc.;

[0076] - a floating vehicle such as a boat, a drone, etc.;

[0077] - an underwater vehicle, ...

[0078] In the context of the invention, a “rear base” (RB) can designate any system configured to be in communication with a mission vehicle.

[0079] The communication between a BA and one or more VM(s) can be based on any type of wireless transmission technology, such as for example radio transmissions in any type of RF band (for example ad-hoc WiFi transmission), transmissions on the visible part of the electromagnetic spectrum (for example LiFi transmissions) or even acoustic transmissions (for example underwater).

[0080] A BA may be fixed (110, 112) or mobile (114), e.g. such as a boat responsible for communicating with submarines.

[0081] Thus a BA can take different forms such as for example:

[0082] - a server in the internet or a “cloud” platform in charge of receiving (and potentially store and / or process) the data collected and transmitted by the VM during its movement;

[0083] - a control center, supervision center for example in charge of supervising one or several autonomous drones (for example a fleet of drones); in this context, the data exchanges between the BA and the VM(s) may be, for example, mission instructions (for example, a trajectory to follow) transmitted to the drone(s) or data (for example, videos, photos, event detection alerts, etc.) collected by the drone(s) and transmitted to the BA;

[0084] - a control console (or remote control) for tele-operation of a drone or robot allowing the drone / robot to be remotely piloted and a video stream captured by the drone / robot to be viewed;

[0085] - etc.

[0086] Thus, the present invention can be implemented with variants of these configurations and can be applied to the multiple scenarios mentioned or to others defined by new missions.

[0087] [Fig.2a] illustrates an example of a communication network established between a VM (202) and a BA (204) by the installation of several “Autonomous Robotic Communication Relays or RCRA” (206) deployed on the trajectory of the VM during its movement.

[0088] Advantageously, the method for deploying a communication network according to the invention allows automatic configuration of a linear wireless mesh communication network between the VM and the BA, this network being able to be made up of a plurality of RCRAs, thus making it possible to extend the wireless coverage between the VM and the BA and allowing the two entities to remain connected without constraining the VM in its movements.

[0089] An RCRA device according to the invention is an entity capable of moving autonomously along the trajectory followed by the VM and stationing at a position which is calculated to allow establishing, as a communication relay, a multi-hop linear wireless communication between the VM and the rear base. An RCRA according to the applications can be a terrestrial device, an aerial device performing a stationary flight such as a drone, a floating or underwater device.

[0090] According to alternative embodiments, the RCRAs can be equipped with any type of sensors or actuators potentially useful to the VM in carrying out its mission. The VM can then, thanks to the linear wireless network, collect information from these additional sensors, thus enabling it to “increase” its perception along its past trajectory. In the same way, the VM can then, again thanks to the linear wireless network, control the actuators of the RCRAs and thus “increase” its capacity for action along its past trajectory.

[0091] Thus, [Fig.2a] shows a situation where the VM which has already evolved on its trajectory since its departure where it was in direct communication with the BA, required the deployment of three communication relays RCRA(l) (206-1), RCRA(2) (206-2), RCRA(3) (206-3) in order to maintain quality wireless connectivity between itself and the BA (204).

[0092] The method according to the invention makes it possible to automatically calculate the positioning of each RCRA to be deployed along the trajectory of the VM, as well as the addition if necessary of a new RCRA, so as to preserve the wireless connectivity between the VM and the BA and to ensure that it is of sufficient quality to route the data exchanges between the VM and the BA bidirectionally despite the movement of the VM.

[0093] [Fig.2b] illustrates a situation subsequent to [Fig.2a] where the VM having moved, it was determined that in order to maintain a sufficient level of quality of communications, a new RCRA (206-4) had to be added to the linear mesh-hop wireless communication network established between the VM (202) and the BA (204).

[0094] The example taken for figures 2a and 2b is simplified to allow the principles of the invention to be described, but those skilled in the art understand that any other deployment of RCRAs in number and position on the trajectory of a VM is not limited by this example.

[0095] In one embodiment, the RCRAs are grouped in a zone called the reserve zone (208) from which they can leave to position themselves autonomously at the planned position which is calculated during the movement of the VM. Thus according to the examples illustrated, the reserve zone (208) contains three RCRAs waiting in [Fig.2a], and only contains two in [Fig.2b] after sending the RCRA(4) to the position which was calculated for it.

[0096] [Fig.3] illustrates a module (300) of the main functional characteristics of a rear base (BA) making it possible to implement the method of the invention in one embodiment.

[0097] The functional module (300) of a BA comprises a communication interface (ifc) associated with an IP address (IPv4 or IPv6) called “@BA” (304). This communication interface (302) allows the BA to communicate:

[0098] - with the RCRAs located in the reserve zone and which are within wireless range direct from the BA (i.e. not requiring relaying of communications);

[0099] - with a VM at the start of the mission (when the BA and the VM are in range direct wireless);

[0100] - with an RCRA positioned at the end of the queue (the last RCRA added to the wireless network- linear mesh wire) and which is also in direct wireless range with the BA.

[0101] The functional module (300) of a BA also comprises a routing table (306) for routing data flows from the BA to a VM, as well as the control commands for VM configurations and RCRAs. The routing table makes it possible to indicate for a given destination address (for example the address of a VM), whether it can be reached directly via the ifc interface (302) or whether communications must be routed via a relay, which can be indicated by a mention of "NextHop" in the routing table.

[0102] The routing table (306) may also include a default entry that allows routing all flows to an IP address for which the routing table does not contain a specific routing entry.

[0103] When starting a mission, the routing table of a BA is configured in “default” mode, as follows:

[0104] NextHop Default = <vide>via ifc

[0105] Thus, all RCRAs in the reserve zone and the VM can be reached in direct wireless range via the BA ifc interface upon initialization.

[0106] The functional module (300) of a BA also comprises a sub-module (308) designated by the “Father” field (308) making it possible to trace the connectivity relationship of the BA to a VM, via the possible multiple RCRAs, through the linear mesh wireless communication network. At the start of a mission, the “Father” field is configured with the identifier of the VM (for example the IP address of VM: @VM), then is updated as the VM moves with the identifier of the last RCRA (for example the IP address of this RCRA) added to the linear wireless network, the last RCRA constituting the first relay point for communications addressed to VM, and is therefore the “Father” of the BA.

[0107] The functional module (300) of a BA also comprises a sub-module (310) for receiving the trajectory of the VM (the trajectory being transmitted by the VM). The module trajectory reception (310) allows the BA to store the trajectory (T) of the VM from the initial starting point of the VM and throughout its movement. The trajectory data which are stored are transmitted by the BA to a new RCRA (initially in the reserve zone) to configure it for integration into the linear wireless network. In one embodiment, the trajectory T of a VM can be materialized in the form of a temporal sequence of successive positions of the VM determined at regular time intervals (for example every 100 milliseconds). The trajectory T of the VM is not necessarily predefined, it can be adaptive according to the needs and constraints of the mission to be accomplished by the VM. A VM, whether driven, remote-controlled, or autonomous, can for example adapt its trajectory to avoid an obstacle or simply because the objective of its mission (for example a target area to reach, to inspect, etc.) has changed.

[0108] The functional module (300) of a BA also comprises a sub-module (312) for monitoring the quality of the direct wireless communication link between the BA and its “Father”. This module (312) makes it possible to anticipate the loss or imminent degradation of this direct link by analyzing the quality of the communication link, in order to allow the addition of an additional RCRA to the linear wireless network when the quality falls below a certain threshold S.

[0109] In one embodiment, the threshold S is predefined at the start of the mission, it is the same for all the equipment of the linear wireless network (the BA, the RCRAs, the VM) and it remains constant throughout the mission.

[0110] In an alternative embodiment, the threshold S is predefined at the start of the mission, it is the same for all the equipment of the linear wireless network (the BA, the RCRAs, the VM), but it is (1) dynamically recalculated by the BA each time an RCRA is added or removed from the linear wireless network and (2) dynamically pushed to the equipment still present in the linear wireless network (the BA, the RCRAs, the VM) during their reconfigurations. In this alternative, the calculation of the new threshold S to be applied can be determined on the basis of an end-to-end communication quality objective between a VM and the BA (for example a throughput or latency objective, etc.) and the number of RCRAs present in the linear wireless network.

[0111] As an illustration of this variant, adding an RCRA, and therefore an additional level of relaying of communications between a BA and a VM, can reduce the maximum available end-to-end throughput between the BA and the VM if the threshold S is not adjusted. On the other hand, by adjusting the threshold S so as to improve the quality of the connectivity of the direct link between each Son and its Father within the linear wireless network (for example by imposing a higher quality of the radio signal between the Son and the Father, and therefore potentially a shorter maximum distance between the two) it is possible to increase the throughput available between each Son and its Father, and therefore the throughput available end-to-end between the BA and the VM, and thus counterbalance the addition of an RCRA. Each of the RCRAs in the linear wireless network will readjust its position along the VM's trajectory T to respect this new threshold S once it has been configured.

[0112] The functional module (300) of a BA also comprises a sub-module (314) for controlling the configurations of the BA, of each of the RCRAs (located in the reserve zone or integrated into the linear wireless network) and of the VM.

[0113] The configuration control module (314) includes code instructions for executing operations to integrate, when necessary, a new RCRA into the linear mesh wireless communication network between the VM and the BA (method described with reference to [Fig.7]), and for executing operations to gradually dismantle the RCRA network between the BA and the VM in fallback mode (method described with reference to Figures 10a and 10b).

[0114] [Fig.4] illustrates a module (400) of the main functional characteristics of an autonomous robotic communication relay (RCRA) making it possible to implement the method of the invention in one embodiment.

[0115] The functional module (400) of an RCRA comprises a communication interface (ifc) associated with an IP address (IPv4 or IPv6) called “@RCRA” (404). This communication interface (402) allows an RCRA to communicate:

[0116] - with a BA at the start of the mission when it is in the reserve zone (the BA being in direct wireless range);

[0117] - with its neighbors (the BA, the VM or other RCRA) according to its position in the network linear wireless once RCRA was added to the network.

[0118] The RCRA functional module (400) further comprises a routing table (406) for routing communications between a BA, a VM and the other RCRAs possibly present in the linear wireless network.

[0119] At the start of a mission, the routing table of an RCRA (which is then in the reserve zone) is configured to indicate that the BA can be reached within direct wireless range via the RCRA's ifc interface, as follows:

[0120] @BA NextHop = <vide>via ifc

[0121] The functional module (400) of an RCRA also includes two sub-modules (408, 410) designated by the fields "Father" (408) and "Son" (410) which are used to trace the connectivity relationship from a BA to a VM through the linear mesh wireless communication network when the RCRA is integrated into the network.

[0122] At the start of the mission, the Father (408) and Son (410) fields of each RCRA (which are then in the reserve zone) are empty. As soon as an RCRA must be integrated into the linear wireless network, its Father and Son fields are completed with the identifiers of its neighbors in the network. The Father field is filled with the identifier of the RCRA which is the upstream neighbor RCRA to the VM (or be filled with the identifier of the VM itself if the RCRA is the first integrated into the network), and the Son field is filled with the identifier of a neighbor RCRA which will be the downstream neighbor RCRA to the BA (or be filled with the identifier of the BA itself).

[0123] The functional module (400) of an RCRA also comprises a location system (412) (which may be identical to that of a VM), allowing it to know at any time its position in the environment in which it is evolving. Advantageously in the context of the invention, the location system allows the RCRA to be able to position itself along the trajectory T which it receives from the VM via a “VM trajectory reception” sub-module (414).

[0124] At the start of a mission, all the RCRAs being in the reserve zone, none of them receives the trajectory T of the VM. As soon as an RCRA is integrated into the linear wireless network, it can then receive the trajectory T of the VM and progress autonomously along this trajectory following the implementation of sub-processes described with reference to figures 6a and 9.

[0125] The functional module (400) of an RCRA also comprises a sub-module (416) for transmitting the trajectory T of a VM to its “Son” (the BA or the previous neighboring RCRA to the BA in the linear wireless network). The module (416) for transmitting the trajectory T of a VM is used when the RCRA is integrated into the linear wireless network.

[0126] The functional module (400) of an RCRA further comprises a sub-module (418) for monitoring the quality of the direct wireless communication link between itself and its “Father”. This module (418) is used as soon as the RCRA is integrated into the linear wireless network, thus allowing this RCRA to anticipate the imminent loss or degradation of the direct communication link with its “Father” and to adjust its position on the VM trajectory T accordingly (mainly with a view to getting closer to its Father) so as to preserve quality connectivity between the RCRA and its Father. This module is used in the method described with reference to [Fig.6a],

[0127] The functional module (400) of an RCRA further comprises a sub-module (420) for “receiving the RCRA configuration” transmitted by the BA. This module is activated by the method described in [Fig.7] of the operations of a BA to integrate a new RCRA into the linear mesh wireless communication network between the VM and the BA, when necessary. It is also activated by the method described in figures 10a and 10b of the operations of a BA to gradually dismantle the RCRA network between the BA and the VM in fallback mode.

[0128] It should be noted that a change in the configuration of an RCRA is necessary as soon as it is inserted into the linear wireless network (from the reserve zone), or when it is removed from the linear wireless network (to re-enter the reserve area) or that another RCRA directly adjacent to this RCRA must be integrated into or removed from the linear wireless network.

[0129] In one embodiment, an RCRA may also be equipped with obstacle detection or anti-collision systems to prevent it from hitting obstacles during its autonomous navigation. Such systems may rely on different types of environmental perception sensors such as cameras, radars, lidars or others...

[0130] [Fig.5] illustrates a module (500) of the main functional characteristics of a mission vehicle (VM) making it possible to implement the method of the invention in one embodiment.

[0131] The functional module (500) of a VM comprises a communication interface (ifc) associated with an IP address (IPv4 or IPv6) called “@VM” (504). This communication interface (502) allows a VM to communicate:

[0132] - with a BA at the start of the mission, the BA and the VM being in wireless range direct;

[0133] - with the RCRA lead (the first added to the linear wireless mesh network) in direct wireless range with the VM, since moving the VM no longer allows the BA and the VM to communicate in direct wireless range.

[0134] The functional module (500) of a VM further comprises a routing table (506) for routing data flows from the VM to the BA. This routing table makes it possible to indicate, for a given destination address (for example that of the BA), whether it can be reached directly via the ifc interface or whether communications must be routed via a relay (indicated as “NextHop” in the routing table).

[0135] When starting a mission, the routing table of a VM is configured to indicate that the BA can be reached in direct wireless range via the ifc interface of the VM, as follows:

[0136] @BA NextHop = <vide>via ifc

[0137] The functional module (500) of a VM also comprises a sub-module (508) designated by the “Sons” field making it possible to trace the connectivity relationship from the BA to a VM, via the possible multiple RCRAs, through the linear mesh wireless communication network.

[0138] At the start of a mission, the “Son” field is configured with the identifier of the BA (for example the IP address of the BA: @BA), then it is updated by the identifier of the first RCRA (for example the IP address of this RCRA) added to the linear wireless network and constituting the first relay point for communications addressed to BA (this RCRA is the “Son” of the VM).

[0139] The functional module (500) of a VM also comprises a location system (510) allowing it to know its position in the environment at any time. which it evolves.

[0140] A location system (510) equipping a VM (but also an RCRA) can be for example:

[0141] - a satellite location system: GPS, Galileo, Glonass, etc. In this case the VM position information can be an absolute position coordinate relative to the terrestrial reference frame (for example a triplet: longitude, latitude, altitude, etc.).

[0142] - a location system via a radio infrastructure deployed on the ground such as a UWB (Ultra Wide Band) localization infrastructure.

[0143] - a vision localization system using one or more cameras, in particular via SLAM (“Simultaneous Localization And Mapping”) techniques. In this case, the VM position information may be relative position information with respect to a point of origin (for example the position of the VM at the start of the mission); this information may possibly be converted into absolute position information as soon as the position at the point of origin according to an absolute location reference is known (for example the GPS coordinates of the position at the origin).

[0144] - a hybrid system mixing several localization techniques such as satellite systems, SLAM, or systems using other types of sensors (inertial units, compasses, accelerometers, odometers, etc.).

[0145] Thus, different localization systems and techniques can be used in a complementary manner depending on the environment in which the VM operates, for example by directly exploiting a GPS system in an outdoor environment (where GPS coverage is available) and by switching to a SLAM localization system (possibly coupled with other sensors) in an indoor environment (where GPS coverage is not available).

[0146] The functional module (500) of a VM further comprises a module (512) for calculating and transmitting its trajectory T to its “Son” (the BA or the first RCRA added to the linear wireless network).

[0147] In one embodiment, the trajectory T of a VM is materialized in the form of a temporal sequence of successive positions of the VM, which are determined at regular time intervals (for example every 100 milliseconds).

[0148] In the case of a GPS location system, the trajectory of a VM may consist of a time sequence of triplets (longitude, latitude, altitude) determined at regular time intervals (for example, intervals of 100 milliseconds) from the initial position point of the VM at the start of the mission.

[0149] The functional module (500) of a VM further comprises a module (514) for receiving the VM configuration transmitted by the BA. This module is activated by the method described in [Fig.7] of the operations of a BA to integrate a new RCRA into the linear wireless mesh communication network between the VM and the BA, when necessary.

[0150] This module is also activated by the method described in Figures 10a and 10b of the operations of a BA to gradually dismantle the RCRA network between the BA and the VM in fallback mode.

[0151] [Fig.6a] is a flowchart of the steps (600) operated by an RCRA already integrated into a linear mesh wireless communication network, established between a BA and a VM, along the trajectory of a VM.

[0152] The method (600) is described for an RCRA 'N' which can be any RCRA of the linear wireless network. The operations allow the RCRA 'N' to anticipate the upcoming loss or degradation of the direct communication link with its Father and to adjust accordingly its position on the trajectory T of the VM (in order to get closer to its Father) so as to preserve quality connectivity between it and its Father, and therefore preserve the quality of the connectivity between the BA and the VM.

[0153] By default, the RCRA is stopped (602). Thanks to its module (418) for monitoring the quality of the direct wireless communication link between itself and its “Father”, the RCRA evaluates (604) the quality Q of the direct connectivity between itself and its Father, for example at regular time intervals. If this falls below a predefined threshold S (Yes branch of 606), then the RCRA starts moving (608) and progresses along the trajectory T of the VM in order to get closer to its Father, otherwise the RCRA remains in the state (604) of monitoring the quality of the connectivity (No branch of 606). The trajectory T of the VM is known to the RCRA because it receives it from its Father via the “VM trajectory reception” module (414).

[0154] Several variants are possible concerning the step (606) of determining the exceeding of a threshold S, relative to the quality of the direct link between the RCRA 'N' and its Father. Thus, for example, the determination can be made:

[0155] - Based on a single quality measurement directly compared to the threshold S;

[0156] - Based on several consecutive measurements (e.g. at time intervals regular) and the calculation of an average of this quality, with then a comparison of this average calculated at the threshold S;

[0157] - Based on several consecutive measurements (e.g. 10 measurements at intervals regular times) and the number of times these measurements exceed the threshold S: if this number itself exceeds a predefined threshold (for example 7 times out of 10) then it is considered that the quality of the link exceeds the threshold S. This approach has the advantage of overcoming any possible variabilities in the signal propagation channel between the RCRA and its Father.

[0158] During its movement along the trajectory T, the method allows the RCRA to continue to evaluate (610) the quality of its direct connectivity between itself and its Father, and as soon as the quality Q returns above the threshold S, the RCRA stops again (612).

[0159] Thus, the RCRA dynamically adapts its position along the trajectory T of the VM so as to preserve quality connectivity between itself and its Father.

[0160] Different and several quality indicators Q of the link between an RCRA and its Father can be used such as for example:

[0161] - Quality indicators associated with the level of the transmission signal (e.g. example a radio signal or an acoustic signal): the strength of the signal received from the Father, the RSSI (Received Signal Strength Indication);

[0162] - Connectivity quality indicators related to link performance, such as For example : - The MCS (“Modulation and Coding Index”) allowing the theoretical flow rate of the link to be estimated; - Evaluation of the available application throughput taking into account the MCS and the transmitted (TX) and received (RX) data indicators on the link between the RCRA and its Father; - The measurement of latency (for example the measurement of the “Round Trip Time” (RTT)) between the RCRA and its Father; - Etc. - Or any combination of these indicators.

[0163] Each RCRA of the linear wireless network applying this same method (600), the linear wireless network made up of all of these RCRAs then makes it possible to maintain quality connectivity between a BA and a VM, as long as the last RCRA added to the mesh wireless network (i.e. closest to the BA) is not too far from the BA.

[0164] If the last RCRA added to the network becomes too far from the BA due to its movement, the method of the invention then makes it possible to trigger a procedure (700) to add a new RCRA to the linear wireless network.

[0165] [Fig.6b] is a flowchart of a variant of the method of [Fig.6a] where identical steps have the same references and are not described in detail.

[0166] The variant in the method (601) of [Fig.6b] consists of an optional extension which makes it possible, in addition to ensuring the quality of the link between an RCRA and its Father, to ensure that the RCRA respects at all times a minimum safety distance (ds) between itself and its Father.

[0167] The monitoring step (605) consists of the RCRA monitoring the quality Q of the link but also the distance between it and its Father.

[0168] An RCRA only starts moving (608) if the quality of the link falls below the predefined threshold S and the distance between it and its Father is greater than the predefined safety distance 'ds' (Yes branch of step 607), otherwise the RCRA remains in the state double quality and distance monitoring (605).

[0169] In this embodiment, each of the RCRAs broadcasts its own position (Pos) to its Son, for example at regular intervals, in addition to transmitting the trajectory T of the VM to its Son.

[0170] Thus each RCRA of the linear wireless network can calculate the distance between itself and its Father by knowing the position of its Father (received from the latter) and its own position, determined using the location system (412) integrated into the RCRA.

[0171] During its movement along the trajectory T, the method allows the RCRA to continue to evaluate (609) the quality of the direct connectivity between this RCRA and its Father as well as the minimum safety distance (ds) between it and its Father. When the quality Q returns above the predefined threshold S, or when the minimum safety distance 'ds' is no longer respected, the RCRA stops again (612).

[0172] [Fig.7] is a flowchart of the steps (700) performed by a BA to integrate a new RCRA (stored in a reserve area) into a linear mesh wireless communication network established between a BA and a VM.

[0173] The method (700) is described by assuming that the linear wireless network already integrates a plurality 'N' of RCRAs, designated by RCRCA(l), RCRA(2), RCRA(N), and positioned in this order 1 to N from a VM to a BA along the trajectory T of the VM.

[0174] The operations (700) carried out by a BA (i.e. the method operated by a BA) to decide whether a new RCRA(N+1) must be integrated, and to integrate it if necessary into the linear wireless mesh communication network between the VM and the BA, consist of:

[0175] Steps (702, 704): the BA monitors (702) the quality of the link with its Father (RCRA(N) in the example) and if this falls below a certain predefined threshold S (Yes branch of 704), making it possible to anticipate a loss or a degradation of the quality of the connectivity with the RCRA(N), the BA then carries out the following steps:

[0176] Step (706): position the new RCRA(N+1) (initially located in the reserve zone) by activating its movement towards the initial position of the trajectory T of the VM (the initial position of the trajectory T of the VM being the starting point of the VM at the start of the mission). This initial position is known to the BA which receives it via its VM trajectory reception module (310).

[0177] Step (708): when the RCRA(N+1) has arrived autonomously from the reserve zone at the initial position of the VM trajectory, the BA carries out a first step of configuring the RCRA(N+1) with a view to integrating it into the linear wireless network between the BA and the RCRA(N).

[0178] [Fig.8a] details an embodiment of the first configuration step (708) of the RCRA(N+1), and which consists of:

[0179] - Step (708-1): reconfigure the routing table (406) of the RCRA(N+1) by indicating that :

[0180] - The RCRA(N) (currently the Father of the BA) can be contacted directly via its ifc interface; and

[0181] - The RCRA(N) is the "default nexthop" to reach all other RCRAs in the network and the VM.

[0182] - Step (708-2): Configure the module (408) by indicating that the Father of the RCRA(N+1) is the RCRA(N).

[0183] - Step (708-3): Configure the module (410) by indicating that the Son of the RCRA(N+1) is the BA.

[0184] - Step (708-4): Activate at RCRA(N+1) level the module (414) for receiving the trajectory of the VM from the RCRA(N).

[0185] - Step (708-5): Activate at the RCRA(N+1) level the module (416) for transmitting the trajectory of the VM towards the BA.

[0186] - Step (708-6): Activate the monitoring module (418) at RCRA(N+1) level of the quality of the direct link with his Father RCRA(N).

[0187] Thus, at this stage the RCRA(N+1) is ready to integrate the linear wireless network but it is not yet truly integrated since the reconfigurations of the RCRA(N) (the current father of the BA) and the BA have not yet been put in place.

[0188] Returning to [Fig.7], the method continues after step (708), with a step (710) allowing the BA to reconfigure the RCRA(N) (its current father) to indicate to it that a new RCRA(N+1) (the future Father of BA) is now to be taken into account between the BA and the RCRA(N).

[0189] [Fig.8b] details an embodiment of step (710) which consists of:

[0190] - Step (710-1): Reconfigure the RCRA(N) routing table (406) by indicating that :

[0191] - The RCRA(N+1) can be directly reached via its ifc interface;

[0192] - The BA is now reachable via the RCRA(N+1) (NextHop)

[0193] - Step (710-2): Configure the module (410) by indicating that the Son of the RCRA(N) is theRCRA(N+l).

[0194] - Step (710-3): Reconfigure the VM trajectory transmission module (416) (initially transmitted to BA) to now transmit it to its new Son, i.e. the RCRA(N+1).

[0195] Returning to [Fig.7], the method continues after step (710), with a step (712) allowing the BA to reconfigure itself.

[0196] [Fig.8b] details an embodiment of step (712) which consists of:

[0197] - Step (712-1): add the RCRA(N+1) to a list 'L' of RCRAs integrated into the network linear mesh wireless.

[0198] - Step (712-2): reconfigure the BA routing table (306) by indicating that:

[0199] - for all RCRAs other than RCRA(N+1) included in list 'L' (i.e. included in the linear wireless network), these can be reached via the RCRA(N+1) (NextHop);

[0200] - the VM is now reachable via the RCRA(N+1) (NextHop).

[0201] - Step (712-3): Configure the module (308) by indicating that the Father of BA is now the RCRA(N+1).

[0202] - Step (712-4): Configure the VM trajectory reception module (310) (initially transmitted from RCRA(N)) to receive the trajectory now from its new Father, RCRA(N+1).

[0203] Returning to [Fig.7], the method continues after step (712), with a step (714) allowing the BA to carry out a second step of configuring the RCRA(N+1) which is now added to the linear wireless network. As illustrated in [Fig.8b], this second step of configuring the new RCRA(N+1) consists of pushing towards (i.e. sending to; transmitting to) this RCRA(N+1) the entire trajectory of VM which has already been received by the BA. Thanks to this information and to the next updates of the location of VM which will be received directly by the RCRA(N+1) (thanks to its activated reception of the trajectory of VM from its Father RCRA(N)), the RCRA(N+1) will have knowledge of the entire trajectory of VM from the start of the mission until time 't'.

[0204] Once the process (700) operated by a BA is completed, the linear wireless network between the BA and the VM has been updated with the addition of an RCRA(N+1) which has come to position itself between the BA and the RCRA(N). The RCRA(N+1) is now the Father of the BA (716).

[0205] [Fig.9] is a flowchart of the steps performed by an RCRA integrated into a network, in fallback mode.

[0206] In an advantageous embodiment, the present invention also comprises a fallback mode allowing, when a VM turns back along its initial trajectory, an automatic fallback of the RCRAs positioned along this same trajectory and a dismantling of the mesh network formed by the RCRAs. The dismantling is progressive via the removal of the RCRAs from the mesh network as and when they are no longer necessary to preserve quality connectivity between the VM and the BA.

[0207] This mode is particularly interesting since it makes it possible to limit the number of RCRAs to be deployed (typically halve this number) in order to allow the VM to reach its initial point at the end of the mission. In addition, it is particularly interesting when the VM is moving in an extremely cramped environment (such as a corridor) which does not physically allow a VM and an RCRA to cross paths.

[0208] The fallback mode is triggered at the initiative of a BA when a VM must turn back along its initial trajectory. The BA then transmits to each of the RCRAs of the linear wireless network a “fallback order”, which will then initiate at each of the RCRAs receiving this message the method (900) described with reference to [Fig.9].

[0209] The method (900) begins upon receipt (902) by an RCRA(N) integrated into the linear wireless network, of a message signifying an order to fall back along the trajectory T of a VM, the RCRA(N) then being stopped or stopping if it was in motion.

[0210] In a following step (904), the method allows the RCRA(N) to deactivate its module (418) for monitoring the quality of the link with its Father, then continues with a step (906) allowing the RCRA(N) to activate the module (412) for transmitting its location to its Son.

[0211] In a following step (908), the method makes it possible to activate the reception of the location of the Father of RCRA(N), and on the basis of this information and of its own location of RCRA(N), to make (910) a regular calculation of the distance between itself RCRA(N) and its Father.

[0212] As soon as this distance falls below the threshold of a predefined fallback distance (dr), the method allows (912) the RCRA(N) to start (move) in the opposite direction, according to the trajectory T previously received from VM, and to begin its fallback towards the point of origin of the trajectory T. When the RCRA(N) moves, it continues its monitoring of the distance between itself RCRA(N) and its Father and stops its movement as soon as this distance returns above the fallback distance (dr); the method then loops back to step 910.

[0213] The method allows the RCRA(N) to determine (914) when it has reached the original position of the trajectory T of VM, and to stop (916).

[0214] The removal of the linear wireless network from an RCRA is implemented by the BA in accordance with the method (1000) described with reference to Figures 10a and 10b.

[0215] [Fig. 10a] and [Fig. 10b] are flowcharts detailing steps taken by a BA to dismantle a network of RCRAs in fallback mode, according to the steps consisting of:

[0216] Step 1002: the BA verifies that the linear wireless network contains at least one RCRA (i.e. it verifies that the list L is not empty). If this is not the case, no dismantling is required and the process ends immediately.

[0217] Step 1004: If the list L is not actually empty, the BA transmits a fallback order to each of the RCRAs of the linear wireless network to initiate their fallbacks, the latter initiating the process of [Fig.9].

[0218] Step 1006: The BA then activates the reception of the location of its Father (RCRA_current, in fallback mode according to the trajectory T of the VM).

[0219] Steps 1008, 1010: the BA monitors (1008) the location information until detecting (1010) that its Father has arrived at the origin point of the trajectory T of VM.

[0220] Step 1012: the BA then triggers the reconfiguration of the Father of its Father (i.e. Father(RCRA_current)) by steps:

[0221] - 1012-1: reconfiguration of the routing table of Father(RCRA_current) for indicate that the BA is now reachable in direct range via its ifc interface;

[0222] - 1012-2: reconfiguration of the Son of Father field (RCRA_current) to indicate that his Son is now the BA; and

[0223] - 1012-3: reconfiguration of the emission of the trajectory of VM towards its new Son (ie the BA, replacing the current RCRA).

[0224] The method continues with a step (1014) allowing the BA to reconfigure itself, by the steps:

[0225] - 1014-1: to remove the RCRA_courant from the list L of RCRAs included in the network linear wireless;

[0226] - 1014-2: to reconfigure its routing table (that of BA) to indicate that:

[0227] - now all RCRAs remaining in the linear wireless network (i.e. present in list L) and others than the Father(RCRA_courant) can be reached via the Father(RCRA_courant);

[0228] - the VM is now reachable via the Father(RCRA_courant) (NextHop);

[0229] - the Father(RCRA_current) can be reached in direct wireless range via the ifc interface of BA, as follows:

[0230] “@VM NextHop = Father(RCRA_current) via ifc” and “@Father(RCRA_current) NextHop = <vide>via ifc ».

[0231] - 1014-3: to reconfigure his Father field to indicate that his Father is now Father(RCRA_current); and

[0232] - 1014-4: to reconfigure the reception of the VM trajectory from its new Father (=Father(RCRA_current)).

[0233] The method continues with a step (1016) allowing the BA to reconfigure the current RCRA, to move it to the reserve zone, by the steps:

[0234] - Step 1016-1: resetting the RCRA_current routing table, in deleting all entries except the one indicating that the BA can be reached directly via its ifc interface;

[0235] - Step 1016-2: deactivation of the reception of the VM trajectory from the Father(RCRA_current);

[0236] - Step 1016-3: deactivation of the transmission of the VM trajectory towards the Son(RCRA_current);

[0237] - Steps 1016-4, 1016-5: resetting to “empty” the Father and Son fields of the RCRA_current; and

[0238] - Step 1016-6: activation of the movement of the RCRA_current to a point specific to the reserve area.

[0239] The method continues with a step (1018) allowing the BA to check whether the list L of the RCRAs included in the network is empty or not, and to loop back to the dismantling steps (around 1006) as long as there remains an RCRA in the linear wireless network (i.e. as long as the BA Father is not the VM), or to terminate when the list is empty.

[0240] Advantageously, at any time a BA can interrupt the fallback mode and switch back to normal mode by transmitting an “end of fallback order” to all the RCRAs still present in the linear wireless network (i.e. still present in the list L). Upon receipt of this “end of fallback order”, each of the RCRAs reconfigures itself to switch from fallback mode to normal mode, and the BA also reconfigures itself in the same way.

[0241] In a variant of the invention, the fallback mode can be initiated by a BA even if a VM does not have to return to its initial position. This can for example occur in a scenario where a VM has reached a final position and the communication link between the BA and the VM is no longer necessary. In this case, the BA can decide to proceed with the fallback of the different RCRAs of the linear wireless network according to the methods of figures 9 and 10a-10b, considering that the head RCRA (the one which was in direct range of the VM) then plays the role of VM.

[0242] In an alternative embodiment, the BA, the VM and the RCRAs integrated into the linear wireless network can implement an additional functionality so as to reinforce the robustness of the network in the face of a failure of one or more RCRAs, and thus to allow an automatic reconfiguration of the linear wireless network in order to preserve quality connectivity between the VM and the BA.

[0243] A failure of an RCRA rendering the network inoperable can be due to various causes such as, for example, a breakdown or destruction of the RCRA (e.g., in a military / defense application scenario).

[0244] This additional sub-process of automatic reconfiguration of the linear wireless network, in the event of failure of one or more RCRAs, is implemented by each of the equipment (BA, VM and RCRAs) forming part of the linear wireless network. The RCRAs have been integrated into the linear wireless network in an order corresponding to their identification number, such that RCRA(l) is the Son of the VM, RCRA(2) is the Son of RCRA(l), etc., and the IP address of each RCRA can be directly calculated / derived from its identifier.

[0245] With these prerequisites, the sub-process for reconfiguring the network in the event of a failure can be implemented completely autonomously locally by each piece of equipment in the linear wireless network (the BA, the VM and the RCRAs) because each is able to determine the identifiers of its second-level neighbors, and on this basis to self-reconfigure according to the sub-process which consists of:

[0246] - Each of the equipments monitors the presence of its Father (ie if the field is not empty) and its Son (i.e. if the field is not empty) within the linear wireless network, in order to detect a possible failure of these. To do this, the equipment (for example an RCRA(N)) can transmit at regular time intervals a presence test message (for example an "ICMP Echo Request" type message) to its Father and to its Son, and wait in return for a response message to this test from each of them (for example an "ICMP Echo Reply" type response message). If the equipment receives no response from one of its direct neighbors (Father or Son) over a predetermined period of time, typically longer than the interval for sending test messages, the equipment can deduce that the neighbor in question is faulty.

[0247] - As soon as a piece of equipment (for example a RCRA(N)) detects that one of its direct neighbors (for example its Father, a RCRA(Nl)) is faulty, it initiates a self-reconfiguration procedure so as to now consider that its second-level neighbor in the direction of the faulty equipment (in our example this second-level neighbor is therefore the Father of the Father of RCRA(N), i.e. the RCRA(N-2)) comes to replace the faulty node. The RCRA(N) then considers that its new Father must now be the RCRA(N-2) and no longer the RCRA(Nl). In the example, the RCRA(N) self-reconfigures by the following steps:

[0248] - Updated its Father field to indicate that its Father is the RCRA(N-2);

[0249] - Reconfiguration of its routing table by replacing the IP address of the RCRA(Nl) by that of the RCRA(N-2) in all entries where this first appears;

[0250] - Reconfiguration of the reception of the VM trajectory so that it is made from the RCRA(N-2) and no longer from the RCRA(Nl); and

[0251] - Reconfiguration of the direct link quality monitoring so that it is done now with his Father RCRA(N-2) and no longer with the RCRA(Nl).

[0252] It is important to note that the RCRA(N-2) which will also apply this same sub-process, and therefore will also detect the failure of the RCRA(N1), i.e. its Son, will then also self-reconfigure in such a way as to consider that RCRA(N) becomes its new Son in replacement of RCRA(N1) which is faulty. Thus the linear wireless network has self-reconfigured automatically, with the exclusion of the faulty RCRA(N1), in such a way as to maintain quality connectivity between BA and VM.

[0253] In the particular case where the faulty equipment is the last RCRA added to the linear wireless network (for example an RCRAX), which is therefore the Father of the BA, then the RCRA(Xl), i.e. the Father of the faulty node, can detect the failure of the RCRAX, but it is not aware of the fact that the BA is in fact the Son of the faulty node. It will reconfigure itself autonomously according to the assumption that its new Son must be the RCRA(X+1) while this RCRA is not yet integrated into the linear wireless network. Also, within the framework of this sub-process, the BA adopts an additional behavior consisting, when it also detects the failure of its Son (RCRAX) to add (from the reserve zone) the new RCRA(X+1) to the linear wireless network, according to the process described with reference to [Fig.7]. Thus the global connectivity is preserved between the BA and the VM via this addition of the RCRA(X+1) and the reconfiguration of the RCRA(Xl).

[0254] In the particular case where the faulty equipment is the first RCRA (i.e. the RCRA(l)) added to the linear wireless network, its Son the RCRA(2) when it detects this fault, will understand that its new Father must now be the VM, since the RCRAO does not exist.

[0255] An advantageous embodiment of the invention is based on a software-defined networking (SDN) oriented architecture. This architecture is based on an SDN controller implemented at the BA level and capable of controlling, via its South Interface, the configurations of a set of SDN equipment, which are then within the scope of the invention (see [Fig.2a]), the BA (204), the VM (202) and all the RCRAs (206).

[0256] In this SDN implementation, the methods described previously with reference to figures 7 and 10a-10b, implemented by the BA can thus be implemented in the form of an SDN Service (at the BA level) interfacing with the SDN Controller via its North Interface, so as to control the configurations of the different SDN equipment reachable via the South interface of the SDN controller.

[0257] This SDN service is thus responsible for detecting that a reconfiguration of the linear wireless network is necessary and then controlling this reconfiguration, via the implementation of reconfigurations on the BA, the VM and the various RCRAs concerned, in order to:

[0258] - BA operations to integrate a new RCRA into the communication network linear wireless mesh communication between the VM and the BA, when necessary;

[0259] - BA operations to gradually dismantle the RCRA network between the BA and the VM in fallback mode.

[0260] In this SDN implementation, the methods described previously with reference to figures 6a, 6b and 9, implemented by an RCRA integrated into the linear wireless network, either in normal mode (figures 6a or 6b) or in fallback mode ([Fig.9]), can be implemented in two different ways:

[0261] - either via a software module at the level of each RCRA;

[0262] - either in the form of an SDN Service at the BA level, this SDN service interfacing with the SDN controller via its North interface so as to be able to control the behavior of the RCRAs integrated into the linear wireless network (these RCRAs being SDN equipment reachable via the South interface of the SDN controller). This control of the behavior of the RCRAs then makes it possible to carry out the operations of the aforementioned methods.< / vide> < / vide> < / vide> < / vide>

Claims

Claims

1. Method (700) for automatically deploying a bidirectional, linear wireless mesh communication network between a mobile vehicle VM and a rear base BA, the mobile vehicle moving from an initial position along a trajectory T, the deployment consisting of creating a queue of communication relay equipment along the trajectory T of the VM, such that the communications between the mobile vehicle and the rear base maintain a communication link quality Q equal to or greater than a threshold value S during the movement of the VM, each communication relay equipment N of the queue being an autonomous mobile equipment called Autonomous Robotic Communication Relay and noted RCRA(N), capable of moving autonomously, the method comprising steps consisting of: a. determining (702, 704) when the quality of the communication link between the rear base and an autonomous robotic communication relay RCRA(N) positioned at the end of the line on the trajectory T, is lower than the threshold value S, the position at the end of the line being that closest to the BA and said RCRA(N) being considered in a father / son connectivity relationship as being the father of the rear base BA; b. sending (706) a new autonomous robotic communication relay noted RCRA(N+1) to position itself along the trajectory T, between the rear base BA and the autonomous robotic communication relay RCRA(N) positioned at the back of the line, the position of the new autonomous robotic communication relay RCRA(N+1) being determined to establish a quality of communication link between said new autonomous robotic communication relay RCRA(N+1) and the BA at a value equal to or greater than the threshold value S; c. configure (708, 710, 712, 714): the autonomous robotic communication relays noted RCRAs already positioned on the trajectory T; the rear base BA; and the mobile vehicle VM; in order to define that the new autonomous robotic communication relay RCRA(N+1) becomes the father of the BA, and define that the linear wireless mesh network between the VM and the rear base BA is updated with the addition of the new autonomous robotic communication relay RCRA(N+1).

2. The method according to claim 1 wherein the step of sending a new autonomous robotic communication relay RCRA(N+1) comprises a first step of activating the movement of the new autonomous robotic communication relay RCRA(N+1) from a reserve zone to the initial position of the trajectory T, the reserve zone grouping a plurality of autonomous robotic communication relays.

3. The method according to claim 1 or 2 wherein the step (708) of configuring the autonomous robotic communication relays RCRAs of the network positioned on the trajectory T, comprises steps of configuring the new autonomous robotic communication relay RCRA(N+1) consisting of: - reconfiguring (708-1) a routing table (406) of the RCRA(N+1) to indicate that the RCRA(N) is directly reachable and that it is the next relay to reach all the other RCRAs of the network and the VM; - identifying (708-2) that the parent of the RCRA(N+1) is the RCRA(N), and (708-3) that the son of the RCRA(N+1) is the BA; - activating (708-4) a module (414) for receiving the trajectory T of the VM from the RCRA(N); - activate (708-5) a module (416) for transmitting the trajectory of the VM towards the BA; and - activate (708-6) a module (418) for monitoring the quality of the direct link with its Father the RCRA(N).

4. The method according to any one of claims 1 to 3 wherein the step (710) of configuring the autonomous robotic communication relays of the network positioned on the trajectory T, comprises steps of configuring the last autonomous robotic communication relay RCRA(N) positioned on the trajectory T, consisting of: - reconfiguring (710-1) a routing table (406) of the RCRA(N) to indicate that the RCRA(N+1) is directly reachable and that the BA is reachable via the new autonomous robotic communication relay RCRA(N+1); - identifying (710-2) that the child of the RCRA(N) is the RCRA(N+1); and - reconfiguring (710-3) a module (416) for transmitting the VM trajectory to activate the transmission of the trajectory to the new child RCRA(N+1) of the RCRA(N).

5. The method according to any one of claims 1 to 4 wherein the step (712) of configuring the rear base BA, comprises steps consisting in: - adding (712-1) the new autonomous robotic communication relay RCRA(N+1) to a list 'L' of the RCRAs integrated into the linear wireless mesh network; - reconfiguring (712-2) a routing table (306) of the BA to indicate that all the RCRAs included in the list 'L', other than the new autonomous robotic communication relay RCRA(N+1), are reachable via the new autonomous robotic communication relay RCRA(N+1), and that the mobile vehicle VM is reachable via the new autonomous robotic communication relay RCRA(N+1); - identifying (712-3) that the parent of the rear base BA is the new autonomous robotic communication relay RCRA(N+1); and - configure (712-4) a VM trajectory reception module (310) to activate the reception of the trajectory from the new RCRA(N+1) parent.

6. The method according to claim 5 wherein the step of configuring the new autonomous robotic communication relay RCRA(N+1) further comprises a step of transmitting to the new autonomous robotic communication relay the entire trajectory T of VM.

7. The method according to any one of claims 1 to 6 wherein the step of configuring the autonomous robotic communication relays RCRAs of the linear mesh wireless network further comprises steps allowing each relay positioned along the trajectory T of the VM to: - monitor (604) the quality of the communication link between it and its parent; and - advance (608) autonomously on the trajectory T when the quality of the link is lower than the threshold value S.

8. The method according to claim 7 wherein the monitoring step further comprises a step (605) of monitoring the distance between it and its father, and the advancing step (608) of advancing when the quality of the link is lower than the threshold value S and the distance between it and its father is greater than a safety distance ds.

9. The method according to any one of claims 1 to 8 further comprising a step of calculating a new value S of the threshold of quality before the configuration stage.

10. The method according to any one of claims 1 to 9 further comprising steps (900) allowing a progressive and automatic withdrawal of the autonomous robotic communication relays positioned on the trajectory T of the mobile vehicle VM, when a VM turns back along its initial trajectory, the withdrawal of the autonomous robotic communication relays leading to a dismantling of the linear mesh wireless network.

11. A computer program product, said computer program comprising code instructions for carrying out the steps of the method according to any one of claims 1 to 10, when said program is executed on a computer.

12. A device for the automatic deployment of a communication network between a mobile vehicle VM and a rear base BA, the device comprising means for implementing the steps of the method according to any one of claims 1 to 10.

13. The device according to claim 12 where the mobile vehicle is a land or air or amphibious or aquatic vehicle, said vehicle being piloted or remotely piloted or self-piloted.

14. An SDN “Software Defined Networking” controller having a North Interface and a South Interface, said SDN controller being capable of controlling via its South Interface the configurations of SDN equipment and of implementing in the form of an SDN Service via its North Interface the steps of the method according to any one of claims 1 to 10, and where said SDN equipment being constituted by the rear base BA, the mobile vehicle VM and all of the autonomous robotic communication relays RCRAs.

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