Method and server for determining map data to be transmitted to a vehicle via a wireless communication network in case of roaming

Abstract

This disclosure relates to a method (30) for determining, by a server, map data to be transmitted to a vehicle via a wireless communication network to which the vehicle is connected, comprising: a determination (S30) of a first set of map data associated with a geographic region, a obtaining (S31) of a single-operator network coverage map associated with a wireless communication network operator, a determination (S33), based on the single-operator network coverage map, of a second set of map data associated with a first geographic extension, a obtaining (S34) of a multi-operator network coverage map associated with a plurality of wireless communication network operators, a determination (S36), based on the single-operator network coverage map and the multi-operator network coverage map,of a third set of cartographic data associated with a second geographical extension. Figure accompanying the summary: Figure 3,

Description

Title of the invention: Method and server for determining map data to be transmitted to a vehicle via a wireless communication network during roaming. Technical field

[0001] The present invention belongs to the field of connected vehicles, and relates more particularly to a method and a server for determining map data to be transmitted to a vehicle via a wireless communication network, when approaching a geographical area insufficiently served by this wireless communication network. State of the art

[0002] Assisted driving functions require accurate and up-to-date road maps. Since traffic conditions vary, autonomous vehicles cannot rely solely on onboard road maps, but must instead continuously download up-to-date map data.

[0003] To enable the downloading of this map data, such vehicles are equipped with wireless communication means, generally a cellular communication interface. These wireless communication means allow a vehicle to connect, via a wireless communication network, to a map data server in order to download the map data of the road network on which the vehicle is traveling.

[0004] Unfortunately, network coverage in a given area is rarely uniform, in terms of access technology or signal strength. Consequently, during a journey, a vehicle does not benefit from a constant data rate for downloading map data from a server. In particular, there are geographical areas without network coverage, known as "white zones," from which it is impossible for a vehicle to contact a server to download map data.

[0005] One solution to this problem is to preload map data when approaching a coverage gap (see, for example, French patent application FR 3106686 A1). To this end, geographical areas without network coverage are referenced on a network coverage map so that all map data associated with the coverage gap is preloaded when the vehicle approaches it.

[0006] However, coverage gaps can vary from one operator to another. Thus, the vehicle may consider that it is about to enter a coverage gap for the operator of the wireless communication network to which it is connected, and so preloading a lot of map data, even though this geographical area is not a blank for another wireless communication network, operated by another operator, to which the vehicle can possibly connect in the case of roaming agreements (“roaming” in Anglo-Saxon literature).

[0007] For example, a vehicle may travel from one country to another, initially connected to the communication network of a first operator. If this first operator does not serve the second country, then the second country will be considered a large coverage dead zone by the vehicle, which will preload a large amount of map data. However, a second operator, with which roaming agreements may exist, may serve this second country and could provide the vehicle with map data in this second country without having to preload it via the first operator's wireless communication network. However, the switchover from the first operator to the second operator may take time, so access to map data for the second country is not immediate. Description of the invention

[0008] The present invention aims to overcome all or part of the limitations of prior art solutions, particularly those described above, by providing a solution that improves the handling of geographical areas without network coverage. In particular, the present invention aims to limit the amount of preloaded map data for geographical areas served by operators other than the standard operator of a communication network to which the vehicle is connected, while ensuring continuity in the availability of map data if a switch from one operator to another is necessary (roaming).

[0009] To this end, he proposed, according to a first aspect, a method for determining, by a server, cartographic data to be transmitted to a vehicle via a wireless communication network to which said vehicle is connected, said method comprising: - a determination of a first set of cartographic data associated with a geographical region around a point of interest for the vehicle, - obtaining a single-operator network coverage card associated with a wireless communication network operator to which the vehicle is connected, referred to as the "current operator", - the determination of a second set of cartographic data associated with an initial geographical extension of the geographical region and without network coverage according to the single-operator network coverage map, - obtaining a multi-operator network coverage map associated with a plurality of wireless communication network operators, - a determination of a third set of cartographic data associated with a second geographical extension of the first geographical extension and without network coverage according to the single-operator network coverage map and the multi-operator network coverage map.

[0010] Thus, the method for determining cartographic data uses two network coverage maps: - a single-operator network coverage map that provides network coverage indications for the vehicle's current operator's wireless communication network, - a multi-operator network coverage map that provides network coverage indications for wireless communication networks from several different operators.

[0011] Therefore, the single-operator network coverage map makes it possible to identify geographical areas without network coverage from the current operator, and the multi-operator network coverage map makes it possible to determine whether geographical areas without network coverage from the current operator are served by other operators that could be used to download map data (subject to roaming agreements).

[0012] It should be noted that, by "no network coverage" for a given wireless communication network, it is meant that it is not possible to connect to this wireless communication network, or that the connection is possible but that the connection which may be established is not suitable for downloading map data (for example due to insufficient bandwidth, or limited to making emergency calls, etc.).

[0013] In general, the method for determining cartographic data involves selecting a first set of cartographic data which corresponds to the basic cartographic data, chosen independently of any consideration of network coverage, which concern a geographical region around a point of interest.

[0014] The method for determining map data also involves selecting a second set of map data relating to a first geographical extension of the geographical region which, according to the single-operator network coverage map associated with the current operator, is without network coverage. The second set therefore corresponds to map data to be preloaded before the vehicle moves into the first geographical extension, which is a white zone (i.e., without network coverage) for the current operator. It should be noted This second set of map data is selected independently of the multi-operator network coverage map, meaning it is independent of whether another operator is available in the first geographic area. Such arrangements allow map data to be preloaded, even for a geographic area without network coverage for the current operator, where a switchover to another operator is likely to occur. Since such a switchover can take time, the map data for the geographic area where the switchover is taking place is preloaded in advance, before a connection can be established with the wireless network of that other operator.The availability of map data in the event of a switch from one operator to another is therefore improved, since the map data associated with the geographical area in which the switch is likely to occur can be pre-loaded before losing the connection with the current operator's wireless communication network and before establishing the connection with the other operator's wireless communication network.

[0015] The method for determining cartographic data also provides for selecting a third set of cartographic data relating to a second geographical extension of the first geographical extension if it turns out, according to the multi-operator (and single-operator) network coverage map, that the second geographical extension is also without network coverage for the other operators, so that it is unlikely that it will be possible to switch to another operator there.

[0016] Thus, the amount of selected map data is greater (due to the addition of the third set) if the probability of being able to re-establish a connection by switching to another operator is low, thereby increasing the service availability time. Conversely, the amount of selected map data is lower if the probability of switching to another operator is high, since in this case the third set of map data is not selected (or is empty).

[0017] Consequently, the method for determining map data improves the availability of map data in the event of a switchover from the current operator to another operator, since the second set of map data is selected as soon as the vehicle is likely to enter a geographical area without network coverage for the current operator. The amount of map data to be preloaded is also limited in the event of a switchover, since the third set of map data is not then selected.

[0018] In particular embodiments, the method for determining cartographic data may further include one or more of the the following optional features, taken individually or in all technically possible combinations.

[0019] In particular embodiments, the first geographical extension is obtained by grouping geographical areas, without network coverage according to the single-operator network coverage map, located outside the geographical region and within a first geographical neighborhood around the geographical region.

[0020] In particular embodiments, the second geographical extension is obtained by grouping geographical areas, without network coverage according to the single-operator network coverage map and the multi-operator network coverage map, located outside the geographical region and outside the first geographical neighborhood and inside a second geographical neighborhood around the first geographical neighborhood.

[0021] In particular embodiments, a geographical area is considered to be without network coverage according to the multi-operator network coverage map if no operator serves said geographical area.

[0022] In particular modes of implementation, a geographical area is considered to be without network coverage according to the multi-operator network coverage map if at least one major operator of a country to which said geographical area belongs does not serve said geographical area.

[0023] In particular modes of implementation, a geographical area is considered to be without network coverage according to the multi-operator network coverage map if no major operator of a country to which said geographical area belongs serves said geographical area.

[0024] In particular embodiments, an operator is considered a major operator in a country if it has network coverage in at least NT% of the country's tiles in which at least one operator has network coverage, NT% being equal to or greater than 60%, or equal to or greater than 70%. A tile corresponds to the map data associated with a given geographic area, and a country corresponds to the union of a plurality of such geographic areas.

[0025] In particular embodiments, the method for determining map data includes receiving an identifier from the current operator, issued by the vehicle, and the single-operator network coverage map is determined based on the identifier received.

[0026] In particular embodiments, the method of determining map data includes a transmission, via the wireless communication network and to the vehicle, of all or part of the map data from the first set, the second set and the third set.

[0027] In particular embodiments, the point of interest corresponds to a geographical position of the vehicle or to a geographical position of a point distant from the vehicle, for example located on a planned route of the vehicle.

[0028] In particular embodiments, the second set of map data is determined when the geographical region includes a border geographical area without network coverage according to the single-operator network coverage map, the first geographical extension extending the geographical region from this border geographical area without network coverage.

[0029] In particular embodiments, the third set of map data is determined when the first geographical extension includes a border geographical area (outside the border with the geographical region) without network coverage according to the single-operator network coverage map and the multi-operator network coverage map, the second geographical extension extending the first geographical extension from this border geographical area without network coverage.

[0030] According to a second aspect, a computer program product is proposed comprising instructions which, when executed by a server comprising at least one memory and at least one processor, configure said server to implement a method for determining map data according to any one of the implementation modes of this disclosure.

[0031] According to a third aspect, a computer-readable recording medium is proposed on which is recorded a set of instructions which, when executed by a server comprising at least one memory and at least one processor, configure said server to implement a method for determining map data according to any one of the implementation modes of this disclosure.

[0032] According to a fourth aspect, a server is proposed comprising at least one processor and at least one memory, configured to implement a method for determining map data according to any one of the implementation modes of this disclosure. Presentation of the figures

[0033] The invention will be better understood upon reading the following description, given by way of non-limiting example, and made with reference to the figures which represent: - [Fig. 1] [Fig. 1]: a schematic representation of a vehicle connected to a wireless communication network, - [Fig.2] [Fig.2]: a schematic representation of an example of a server implementation for determining cartographic data, - [Fig.3] [Fig.3]: a diagram illustrating the main steps of an example of implementing a method for determining cartographic data, - [Fig.4] [Fig.4]: a schematic representation of selected cartographic data in the case where there are no geographical areas without network coverage, - [Fig. 5] [Fig. 5]: a schematic representation of map data selected according to geographical areas without network coverage, in the case where a switch to another operator is considered possible, - [Fig.6] [Fig.6]: a schematic representation of map data selected according to geographical areas without network coverage, in the case where switching to another operator is not considered possible.

[0034] In these figures, identical reference numerals from one figure to another designate identical or analogous elements. For clarity, the elements shown are not to scale unless otherwise stated.

[0035] Furthermore, the order of steps shown in these figures is given only as a non-limiting example of this disclosure which may be applied with the same steps performed in a different order and / or with steps performed in parallel and / or jointly. Description of the implementation methods

[0036] Figure 1 schematically represents a vehicle 10, for example a motor vehicle, traveling on a road in a road network. The vehicle 10 is a connected vehicle comprising a wireless communication device (not shown in the figures) adapted to exchange data with a base station 11 of a wireless communication network, said wireless communication network typically comprising a plurality of geographically distributed base stations 11. The operator of the wireless communication network to which the vehicle 10 is connected is referred to hereafter as the "current operator". The wireless communication device of the vehicle 10 may implement one or more wireless communication protocols for exchanging data with the wireless communication network, and may be, for example, a 3G, 4G, 5G, WiFi, WiMAX, etc., wireless communication device.

[0037] In particular, the vehicle 10 can connect, via the wireless communication network and possibly via a network core 12, to a server 20, in order to obtain map data which can be used in particular for purposes of assisting the driving of the vehicle 10 (alert, navigation, autonomous guidance, etc.).

[0038] Fig. 2 schematically represents an example of the implementation of a server 20 for determining map data to be transmitted to the vehicle 10.

[0039] As illustrated in [Fig. 2], the server 20 also includes a processing circuit 21. The processing circuit 21 includes, for example, one or more processors 210 (CPU, DSP, GPU, FPGA, ASIC, etc.). In the case of several processors 210, these may be integrated into the same equipment and / or integrated into physically separate equipment communicating with each other. The processing circuit 21 also includes one or more memories 211 (magnetic hard drive, electronic memory, optical disc, etc.) in which, for example, a computer program product 212 is stored, in the form of a set of program code instructions to be executed by the processor(s) to implement all or part of the steps of a mapping data determination process 30, which will be described below.

[0040] As illustrated in [Fig. 2], the server 20 also includes a communication module 22 adapted to exchange data with other devices, in particular with the vehicle 10 (via the wireless communication network and, where applicable, the core network 12). The communication module 22 of the server 20 can implement one or more communication protocols, wired (Ethernet, optical, etc.) or wireless (3G, 4G, 5G, WiFi, WiMax, etc.).

[0041] Through the communication module 22, the server 20 is adapted to receive requests from the vehicle 10 and to transmit back information on map data considered relevant to the request from the vehicle 10.

[0042] Figure 1 also represents a geographical area 13 that is not covered by the current operator's wireless communication network. This geographical area is referred to hereafter as "no network coverage" or "white zone" for the current operator. As indicated above, a geographical area without network coverage (or white zone) for a given wireless communication network corresponds to a geographical area in which it is not possible to connect to that wireless communication network, or in which the connection is possible but not suitable for downloading map data.

[0043] If the vehicle 10 moves in the geographical area 13 without network coverage, it will not be possible to receive map data there, at least via the wireless communication network of the current operator, so the presence of this geographical area 13 without network coverage must be taken into account by the server 20 when determining map data to be transmitted to the vehicle 10.

[0044] Fig. 3 schematically represents the main steps of an example of implementation of a method 30 for determining cartographic data, which are implemented by the server 20.

[0045] In the example illustrated by [Fig.3], the determination method 30 aims to determine cartographic data relating to a point of interest for the vehicle 10.

[0046] For example, the point of interest corresponds to the geographic position of vehicle 10. In such a case, the request from vehicle 10 aims to obtain map data around its current geographic position. Regarding the current geographic position of vehicle 10, it is connected to the wireless communication network and is therefore within network coverage. In such a case, the point of interest is received, for example, by the server 20, for instance, in a map data request sent by vehicle 10 and received directly or indirectly by the server 20.

[0047] Following another example, the point of interest corresponds to a geographical position of a point distant from the vehicle 10, which is therefore not necessarily under network coverage. Such a distant point corresponds, for example, to a point located on a planned route of the vehicle 10. In such a case, the point of interest is received, for example, by the server 20, for example, in a map data request sent by the vehicle 10 and received directly or indirectly by the server 20. Following another non-limiting example, the point of interest can be determined by the server 20, for example, based on a planned route of the vehicle 10 received by the server 20, the point of interest being, for example, a point located on the route at a predetermined distance from the current geographical position of the vehicle 10.In some cases, the route can also be determined by server 20 if it receives the current geographic position of vehicle 10 and the geographic position of the desired destination of vehicle 10.

[0048] It should be noted that the determination of map data to be transmitted to the vehicle 10 is carried out, for example, in response to the receipt of a map data request issued by the vehicle 10 and received directly or indirectly by the server 20. However, it is also possible to determine such map data on a recurring basis, for example periodically, based, for example, on the geographical position of the vehicle 10 which can be provided to the server 20 by the wireless communication network.

[0049] As illustrated by [Fig.3], the determination method 30 includes a step S30 of determining a first set of cartographic data associated with a geographical region around the point of interest of the vehicle 10.

[0050] For example, map data is organized into tiles associated with different geographic areas, and the first set of map data may be formed by the tiles associated with the geographic areas located in a predetermined neighborhood of the point of interest. For example, the first set of map data may be formed by the tiles associated with the geographic areas located at a distance from the point of interest that is less than a predetermined maximum distance, and the associated geographic region corresponds to the union of these geographic areas (including the geographic area in which the point of interest is located). Following another example, the first set of map data may be formed by the tile associated with the geographic area in which the point of interest is located, and by the tiles located in a predetermined neighborhood of this tile.For example, if the tiles are indexed in abscissa (e.g., along longitude) and ordinate (e.g., along latitude) and if the tile associated with the geographical area in which the point of interest is located corresponds to the indexed tile ("o" mo) (n and being integers), then the first set of map data corresponds, for example, to the set of tiles whose indices (tl, m) (n and m being integers) are such that n0 - N < n < n0 + N. <m<m0 + M, expressions dans lesquelles N et M sont des entiers prédéterminés qui définissent le voisinage prédéterminé à considérer. Par exemple, dans le cas où une tuile est associée à une zone géographique sensiblement carrée de 2 km de côté, il est possible d’avoir N = M = 4, de sorte que la région géographique est sensiblement carrée de 18 km de côté et le premier ensemble de données cartographiques est constitué de 81 tuiles.

[0051] As illustrated by [Fig.3], the determination method 30 also includes a step S31 of obtaining a single-operator network coverage map associated with the current operator of the vehicle 10. In general, the single-operator network coverage map makes it possible to identify the geographical areas served by the current operator and the geographical areas which are without network coverage for the current operator.

[0052] In particular embodiments, the method 30 for determining map data includes a step in which the server 20 receives (not shown in the figures) a current operator identifier, and the single-operator network coverage map is determined based on the received identifier. For example, the current operator identifier is received in the form of an MCC / MNC pair (for "Mobile Country Code / Mobile Network Code"). However, any current operator identifier format may be implemented in this disclosure, and the choice of a particular format is only a non-limiting variant of the implementation of this disclosure. The operator identifier current is for example emitted by vehicle 10, or is emitted by the current operator's wireless communication network, in order to enable server 20 to obtain the single-operator network coverage card associated with the current operator of vehicle 10. More generally, any means of identifying the single-operator network coverage card to be used may be implemented and the choice of a particular means is only a non-limiting variant of implementation of this disclosure.

[0053] For example, the single-operator network coverage map is obtained from a memory 211 of the server 20, in which said single-operator network coverage map has been previously stored, or from a remote database of the server 20.

[0054] As illustrated by [Fig.3], the method 30 for determining cartographic data includes a step S33 for determining a second set of cartographic data associated with a first geographical extension of the geographical region, said first geographical extension being without network coverage according to the single-operator network coverage map.

[0055] In some cases, the S33 step of determining the second set of map data can be executed systematically, but may nevertheless result in a second set of map data which is empty, if no geographical area in the vicinity of the geographical region is considered to be without network coverage according to the single-operator network coverage map.

[0056] In the non-limiting example illustrated by [Fig.3], the step S33 of determining the second set of map data is carried out under conditions, and the method 30 of determining map data includes a step S32 of evaluating whether the geographical region intersects a geographical area without network coverage according to the single-operator network coverage map. In this example, step S33, which determines the second map dataset, is executed when it is determined that the geographic region (represented by the first map dataset) contains a border area without network coverage, according to the single-operator network coverage map (reference S32a in [Fig. 3]). If applicable, the first geographic extension is obtained, for example, by extending the geographic region from this border area without network coverage, grouping the adjacent areas without network coverage, and incorporating the associated tiles into the second map dataset. In this example, step S33, which determines the second map dataset, is not executed when the geographic region does not contain a border area. border without network coverage according to the single-operator network coverage map (reference S32b on [Fig.3]).

[0057] As its name indicates, the first geographic extension is obtained by grouping geographic areas, without network coverage according to the single-operator network coverage map, located outside the geographic region. In preferred embodiments, such a geographic extension of the geographic region is spatially limited in order to restrict the amount of map data to be included in the second set. As indicated above, the main objective of the second set is to allow the vehicle 10 to have map data for a geographic area without network coverage for the current operator, pending a switchover to another operator if this geographic area is served by another operator.The dimensions of the first geographical extension are therefore advantageously determined to allow vehicle 10 to have mapping data for the entire route it is likely to take in a geographical area without network coverage for the current operator before a switchover to another operator has time to occur.

[0058] For example, the first geographic extension is obtained by grouping geographic areas that are located outside the geographic region but within a predetermined first geographic neighborhood around the geographic region. For example, the first geographic neighborhood may be formed by geographic areas located at a distance from the point of interest that is less than a predetermined first maximum distance (where applicable, greater than the maximum distance considered for determining the geographic region and the first set of map data).Following another example, if the tiles are indexed on the x-axis and y-axis, as shown above, then the first geographical neighborhood corresponds, for example, to the set of geographical areas associated with the tiles whose indices (n, m) are such that (n0-NN^rKUQ-N) and (n0+N <n<nG+N+N{) et (m0-M et (mQ + M < m < mQ + M + Mexpressions dans lesquelles N] et Mj sont des entiers prédéterminés qui définissent le premier voisinage géographique prédéterminé à considérer. Par exemple, dans le cas où une tuile est associée à une zone géographique sensiblement carrée de 2 km de côté, il est possible d’avoir N} -Mx- 10. Suivant un autre exemple, il est possible d’étendre la région géographique, à partir d’une zone géographique frontalière sans couverture réseau de ladite région géographique, en propageant de manière itérative d’une zone géographique frontalière sans couverture réseau à chacune des zones géographiques sans couverture réseau qui lui sont voisines.In other words, the first geographical extension, initially empty, is enlarged. iteratively, for example, until a predetermined maximum number of iterations is reached (e.g., a maximum of 10 iterations). Thus, during the first iteration, the initial geographic extension is expanded by adding all the geographic areas without network coverage that are located outside the geographic region and are contiguous to the geographic area without network coverage bordering the geographic region. During the second iteration, the expansion continues in the same way, starting with the geographic areas without network coverage bordering the initial geographic extension obtained in the previous iteration, and so on.

[0059] It should be noted that, in certain implementations, it is also possible to include in the second set of map data tiles associated with geographic areas with network coverage that are located within the first geographic neighborhood around the geographic region and that are contiguous with geographic areas without network coverage. In other words, this amounts to propagating the first geographic extension until, where possible, a bordering geographic area with network coverage is obtained, according to the single-operator network coverage map. In this way, the second set of map data ensures continuity of service until the vehicle has crossed the coverage gap included in the first geographic extension.

[0060] As illustrated by [Fig.3], the method 30 for determining map data includes a step S34 of obtaining a multi-operator network coverage map associated with a plurality of wireless communication network operators.

[0061] In general, the multi-operator network coverage map provides network coverage information relating to the wireless communication networks of several different operators. As such, the multi-operator network coverage map is intended to enable the server 20 to assess whether, in a geographical area without network coverage for the current operator, there is at least one operator for whom that geographical area is covered by a network. The multi-operator network coverage map thus allows the server 20 to assess the probability that a switchover to another operator could occur in a geographical area without network coverage for the current operator. It should be noted, however, that such a switchover is generally only possible in the case of roaming agreements between the current operator and the other operator.If server 20 has information on existing roaming agreements, then it may be possible to determine with precision whether such a switchover is possible in a given geographical area. If server 20 does not have information on existing roaming agreements, but only on network coverage by other operators, then it is only... It is possible to assess whether other operators serve a geographical area without network coverage for the current operator, without determining with certainty whether such a switchover is actually possible there.

[0062] For example, the multi-operator network coverage map may contain a plurality of layers, each layer corresponding to a single-operator network coverage map associated with a given operator. Where applicable, the single-operator network coverage map of the current operator may, in some cases, be one of the layers of the multi-operator network coverage map. If the multi-operator network coverage map contains a plurality of layers associated with different operators, and if server 20 has information on roaming agreements, then it is possible to identify the layers corresponding to other operators that have a roaming agreement with the current operator. If server 20 does not have information on roaming agreements, then it is possible to consider all the layers associated with operators other than the current operator.

[0063] Following other examples, the multi-operator network coverage map may consist of an overlay that synthesizes the network coverage of different operators. In such a case, the multi-operator network coverage map does not allow for tracing back to the individual network coverage of each operator. In the following description, we consider, without limitation, the case where the multi-operator network coverage map provides, for each geographic area, a synthesis of the network coverage of different operators.

[0064] Following a first example, the multi-operator network coverage map is constructed such that a geographical area is considered to have no network coverage if no operator serves that geographical area. Consequently, such a geographical area is considered to have network coverage if it is served by at least one operator. Such an approach is optimistic with regard to assessing the probability of a switch from the current operator to another operator, since it assumes that a switch is possible as soon as the geographical area has network coverage for at least one operator.

[0065] Following another example, the multi-operator network coverage map is constructed such that a geographical area is considered to have no network coverage if at least one major operator in a country to which that geographical area belongs does not serve that geographical area. Consequently, such a geographical area is considered to have network coverage only if it is served by all the major operators in the country. Such an approach is pessimistic with regard to assessing the probability of a switch from the current operator to another operator, since it assumes that a switch is impossible as soon as the geographical area has no network coverage for a major operator in the country.

[0066] Following another example, the multi-operator network coverage map is constructed such that a geographical area is considered to have no network coverage if no major operator in the country to which that geographical area belongs serves that geographical area. Consequently, such a geographical area is considered to have network coverage if it is served by at least one major operator in the country in which that geographical area is located. Such an approach is therefore intermediate compared to previous approaches with regard to assessing the probability of a switch from the current operator to another operator, since it assumes that a switch is possible as soon as the geographical area has network coverage for at least one major operator in the country.

[0067] For example, server 20 can obtain the identifiers of the major operators in a country and construct the multi-operator (single-layer) network coverage map of that country based on the single-operator network coverage maps associated with said major operators of the country in question.

[0068] Following another example, server 20 can estimate which operators are the major operators in a country based on single-network network coverage maps for each operator. For example, server 20 can determine, for a given country, which geographical areas (tiles) correspond to that country. An operator can then be considered a major operator in that country if it has network coverage in many geographical areas of that country. To determine whether an operator is a major operator in a country, it is advantageous to exclude geographical areas (tiles) in which no operator has network coverage, and to consider only the geographical areas served by at least one operator.For example, an operator is considered a major operator in a country if it has network coverage in at least NT% of the tiles in the country where at least one operator has network coverage, NT% being, for example, equal to or greater than 60%, or equal to or greater than 70%.

[0069] It should be noted that such an approach, based on the major operators of a country, can also be implemented when the multi-operator network coverage map has a plurality of layers, each layer corresponding to a single-operator network coverage map associated with a given operator. If necessary, to verify whether a given geographical area is under network coverage according to the multi-operator network coverage map, the server 20 determines the layers associated with the major operators of the country in which said geographical area is located, and determines whether it is without network coverage for at least one major operator of the country (pessimistic approach above) or for all the major operators of said country (intermediate approach above).

[0070] For example, the multi-operator network coverage map is obtained from a memory 211 of the server 20, in which said multi-operator network coverage map has been previously stored, or from a remote database of the server 20.

[0071] As illustrated by [Fig.3], the method 30 for determining cartographic data includes a step S36 for determining a third set of cartographic data associated with a second geographical extension of the first geographical extension, said second geographical extension being without network coverage according to the single-operator network coverage map (of the current operator) and the multi-operator network coverage map.

[0072] In some cases, the S36 step of determining the third map data set can be carried out systematically, but may nevertheless result in a third map data set that is empty, if no geographical area in the vicinity of the first geographical extension is considered to be without network coverage according to the single-operator network coverage map and the multi-operator network coverage map.

[0073] In the non-limiting example illustrated in [Fig. 3], step S36 of determining the third set of map data is performed under certain conditions, and method 30 of determining map data includes an evaluation step S35 to determine whether the first geographic extension intersects a geographic area without network coverage according to the single-operator network coverage map and the multi-operator network coverage map. In this example, step S36 of determining the third set of map data is performed when it is determined that the first geographic extension (represented by the second set of map data) includes a bordering geographic area (outside the border with the geographic region) without network coverage according to the single-operator network coverage map and the multi-operator network coverage map (reference S35a in [Fig. 3]).If necessary, the second geographic extension is obtained, for example, by extending the first geographic extension from this border area without network coverage, grouping together the geographic areas without network coverage (which are neither in the geographic region nor in the first geographic extension), and incorporating the associated tiles into the third map dataset. In this example, step S36 for determining the third map dataset is not executed when the first geographic extension does not contain a border area without network coverage according to the single-operator network coverage map and the multi-operator network coverage map (reference S35b in [Fig. 3]).

[0074] As its name indicates, the second geographic extension is obtained by grouping geographic areas, without network coverage according to the single-operator network coverage map and the multi-operator network coverage map, located outside the first geographic extension (and outside the geographic region). Such a geographic extension of the first geographic extension is, in particular implementation modes, limited in space in order to limit the amount of map data to be included in the third set.

[0075] For example, the second geographical extension is obtained by grouping geographical areas that are located outside the geographical region and outside the first geographical extension, but within a second predetermined geographical neighborhood around the first geographical neighborhood. For example, the second geographical neighborhood may be formed by geographical areas located at a distance from the point of interest that is less than a second predetermined maximum distance (where applicable, greater than the first maximum distance considered for determining the first geographical extension).Following another example, if the tiles are indexed on the x-axis and y-axis, as shown above, then the second geographical neighborhood corresponds, for example, to the set of geographical areas associated with the tiles whose indices (fl,ni) are such that (nQ-N}-N2 <n<n0-N}) et (n0 + Nl< n<n0 + N j + N2) et (m0M2et (+ Mï <m<m(j + + M2) expressions dans . N2 and M2 are predetermined integers that define the second predetermined geographic neighborhood to be considered. For example, if a tile is associated with a roughly square geographic area of ​​2 km sides, N2 = M2 = 10. As another example, the first geographic area can be extended from a bordering geographic area without network coverage by iteratively propagating from a bordering geographic area without network coverage to each of its neighboring geographic areas without network coverage. In other words, the second geographic area, initially empty, is iteratively enlarged, for example, until it reaches a predetermined maximum number of iterations (e.g., a maximum of 10 iterations).Thus, during the first iteration, the second geographic extension is expanded by adding all geographic areas without network coverage that are located outside the first geographic extension (and outside the geographic region) and that are contiguous to the border geographic area without network coverage of the first geographic extension. During the second iteration, the expansion continues in the same way. in order to start from the border geographical areas without network coverage of the second geographical extension obtained in the previous iteration, etc.

[0076] It should be noted that in certain embodiments, it is also possible not to impose spatial constraints on the second geographic extension (i.e., not to limit it to a second predetermined geographic neighborhood around the first geographic neighborhood). If necessary, however, it is optionally possible to consider a constraint in terms of the quantity of map data, for example, by ensuring that the number of tiles determined does not exceed a predetermined maximum number.

[0077] It should be noted that, in certain implementations, it is also possible to include in the third set of map data tiles associated with geographic areas with network coverage that are located within the second geographic neighborhood around the first geographic neighborhood and that are contiguous with geographic areas without network coverage. In other words, this amounts to propagating the second geographic extension until, where possible, a bordering geographic area with network coverage is obtained, according to the single-operator or multi-operator network coverage map. In this way, the third set of map data ensures continuity of service until the vehicle has crossed the coverage gap included in the second geographic extension.

[0078] The map data determined by the server 20 (first set and, where applicable, the second set and possibly the third set) correspond to map data which the server 20 considers relevant to the point of interest, and which are therefore likely to be transmitted to the vehicle 10.

[0079] For example, the map data thus determined can be transmitted directly to the vehicle 10 by the server 20. As another example, the map data thus determined is, for instance, offered to the vehicle 10 before being transmitted. In other words, the server 20 can transmit to the vehicle 10, as a recommendation, a list of the determined map data, and the vehicle 10 can decide to download all the map data indicated in the list (the first set and, if applicable, the second and possibly the third set) or it can decide to reject them in whole or in part. For example, the vehicle 10 can decide to limit the number of tiles downloaded to a predetermined maximum number of tiles from among those recommended by the server 20.

[0080] In the non-limiting example illustrated in [Fig. 3], the method 30 for determining map data comprises a transmission step S37, via the network of Wireless communication to vehicle 10 of all or part of the specified map data (first set and, where applicable, second and possibly third set of map data). This transmission takes place via the current operator's wireless communication network before vehicle 10 enters a dead zone.

[0081] It should be noted that it is also possible, following other examples, to transmit to vehicle 10 a list of map data determined by server 20, and vehicle 10 can then retrieve all or part of the map data recommended by server 20 from a map database, without going through server 20.

[0082] In the case where the server 20 is responsible for transmitting map data to the vehicle 10, this data is obtained for example from a memory 211 of said server 20, in which said map data has been previously stored, or from a remote database of the server 20.

[0083] Fig. 4 schematically represents the geographical areas associated with the map data determined by server 20, in the case where there are no geographical areas without network coverage for the current operator.

[0084] In the example shown in [Fig. 4], the geographic area containing the point of interest is represented with a black fill, and the first set of map data corresponds to the tiles associated with the geographic areas surrounding the geographic area containing the point of interest (including the tile associated with the geographic area containing the point of interest). The grouping of these geographic areas forms the geographic region RG associated with the map data in the first set. In the example shown in [Fig. 4], the geographic region RG does not contain any geographic areas without network coverage, so step S33 for determining the second set and step S36 for determining the third set are not performed. The map data determined by server 20 is limited in this example to the data in the first set of map data.

[0085] Fig. 5 schematically represents the geographical areas associated with the map data determined by server 20, in the case where there are geographical areas without network coverage for the current operator but a switch to another operator is considered possible.

[0086] Part a) of [Fig. 5] schematically represents the geographic areas (tiles) of the geographic region RG associated with the cartographic data of the first set. As illustrated by part a) of [Fig. 5], the geographic region RG includes bordering geographic areas that belong to a white zone ZB for the current operator (said white zone ZB being represented by a hatched area on part a) of [Fig.5]). Therefore, step S33 of determining the second set is executed.

[0087] Part b) of [Fig. 5] schematically represents the geographic areas (tiles) of the geographic region RG associated with the map data of the first set, as well as the geographic areas (tiles) of the first geographic extension EG1 associated with the map data of the second set. In the example illustrated by part b) of [Fig. 5], the first geographic extension EG1 is, for example, defined within a predetermined first geographic neighborhood VG1 around the geographic region RG, and part of the white zone ZB for the current operator lies outside said first geographic neighborhood. However, in this example, the first geographic extension EG1 does not include any geographic areas without network coverage according to the multi-user network coverage map, so it is likely that a switch to another operator could occur.In this case, step S36 for determining the third set is not executed, and the map data determined by server 20 is limited to the data from the first and second map data sets.

[0088] Fig. 6 schematically represents the geographical areas associated with the map data determined by server 20, in the case where there are geographical areas without network coverage for the current operator and in the case where switching to another operator is not considered possible.

[0089] Part a) of [Fig. 6] schematically represents the geographic areas (tiles) of the geographic region RG associated with the cartographic data of the first set. As illustrated by part a) of [Fig. 6], the geographic region RG includes bordering geographic areas that belong to a white area ZB for the current operator (said white area ZB being represented by a hatched area in part a) of [Fig. 6]). Therefore, step S33 of determining the second set is executed.

[0090] Part b) of [Fig. 6] schematically represents the geographic areas (tiles) of the geographic region RG associated with the map data of the first set, as well as the geographic areas (tiles) of the first geographic extension EG1 associated with the map data of the second set. In the example illustrated by part b) of [Fig. 6], the first geographic extension EG1 is, for example, defined within a predetermined first geographic neighborhood VG1 around the geographic region RG, and a portion of the white zone ZB for the current operator lies outside this first geographic neighborhood. In this example, the white zone ZB is without network coverage not only for the current operator but also for the other operators considered in the map. multi-operator network coverage means that switching to another operator is not considered possible in the ZB white zone. Therefore, step S36, determining the third set, is executed.

[0091] Part c) of [Fig. 6] schematically represents the geographic areas (tiles) of the geographic region RG and the first geographic extension EG1 associated with the map data of the first and second sets, as well as those of the second geographic extension EG2 associated with the map data of the third set. In the example illustrated by part c) of [Fig. 6], the second geographic extension EG2 is determined to cover all geographic areas that are without network coverage according to the single-operator network coverage map and the multi-operator network coverage map. Thus, the white zone ZB is entirely included within the combination of the geographic region RG, the first geographic extension, and the second geographic extension EG2.However, following other examples, nothing precludes limiting the second geographic extension EG2 to a second predetermined geographic neighborhood around the first geographic neighborhood, in which case a large blank area ZB might not be entirely covered by the determined map data. Alternatively or in addition, it is also possible, in certain examples, to constrain the number of tiles that can be transmitted or recommended to vehicle 10 so that this number does not exceed a predetermined maximum number of tiles (for example, a maximum of 5000 tiles), in which case a large blank area ZB might not be entirely covered by the determined map data.

[0092] In the example illustrated by [Fig. 6], the cartographic data determined by Server 20 therefore includes the map data from the first set, the second set, and the third set.

[0093] Thus, the quantity of map data is greater (due to the addition of the third set) if the probability of being able to re-establish a connection by switching to another operator is low ([Fig. 6]). Conversely, the quantity of map data selected is lower if the probability of switching to another operator is high, since in this case the third set of map data is not selected ([Fig. 5]).

[0094] Even if the probability of switching to another operator is significant, map data are nevertheless determined (second set) to improve the availability of map data while the switchover can be carried out.

[0095] More generally, it should be noted that the implementation and realization methods considered above have been described as non-limiting examples, and that other variants are therefore conceivable.

Claims

1. Demands Method (30) for determining, by a server, map data to be transmitted to a vehicle via a wireless communication network to which said vehicle is connected, said method comprising: - a determination (S30) of a first set of cartographic data associated with a geographical region around a point of interest for the vehicle, - obtaining (S31) a single-operator network coverage card associated with a wireless communication network operator to which the vehicle is connected, referred to as the "current operator", - if the geographical region includes a bordering geographical area without network coverage according to the single-operator network coverage map: a determination (S33) of a second set of cartographic data associated with a first geographical extension of the geographical region and without network coverage according to the single-operator network coverage map, regardless of whether another wireless communication network operator is available in the first geographical extension, - obtaining (S34) a multi-operator network coverage map associated with a plurality of wireless communication network operators, - if the first geographical extension includes a border geographical area without network coverage according to the single-operator network coverage map and the multi-operator network coverage map: a determination (S36) of a third set of cartographic data associated with a second geographical extension of the first geographical extension and without network coverage according to the single-operator network coverage map and the multi-operator network coverage map, - a transmission, via the wireless communication network and to the vehicle, of all or part of the determined map data.

2. Method (30) according to claim 1, wherein the first geographical extension is obtained by grouping geographical areas, without network coverage according to the single-operator network coverage map, located outside the geographical region and within a first geographical neighborhood around the geographical region.

3. Method (30) according to claim 2, wherein the second geographical extension is obtained by grouping geographical areas, without network coverage according to the single-operator network coverage map and the multi-operator network coverage map, located outside the geographical region and the first geographical neighborhood and inside a second geographical neighborhood around the first geographical neighborhood.

4. A method (30) according to any one of the preceding claims, wherein a geographical area is considered to be without network coverage according to the multi-operator network coverage map if no operator serves said geographical area.

5. A method (30) according to any one of claims 1 to 3, wherein a geographical area is considered to be without network coverage according to the multi-operator network coverage map if at least one major operator in a country to which said geographical area belongs does not serve said geographical area.

6. A method (30) according to any one of claims 1 to 3, wherein a geographical area is considered to be without network coverage according to the multi-operator network coverage map if no major operator of a country to which said geographical area belongs serves said geographical area.

7. Method (30) according to claim 5 or 6, wherein an operator is considered a major operator of a country if it has network coverage in at least NT% of tiles of the country in which at least one operator has network coverage, NT% being equal to or greater than 60%, or equal to or greater than 70%.

8. A method (30) according to any one of the preceding claims, comprising receiving an identifier from the current operator, issued by the vehicle, and wherein the single-operator network coverage map is determined based on the identifier received.

9. A method (30) according to any one of the preceding claims, wherein the point of interest corresponds to a geographical position of the vehicle or to a geographical position of a point distant from the vehicle, located on a planned route of the vehicle.

10. Product computer program comprising instructions which, when executed by a server comprising at least one memory and at least one processor, configure said server to implement a method (30) for determining map data according to any one of the preceding claims.

11. A computer-readable recording medium on which is recorded a set of instructions which, when executed by a server comprising at least one memory and at least one processor, configure said server to implement a method (30) for determining map data according to any one of claims 1 to 9.

12. Server (20) comprising at least one processor and at least one memory, configured to implement a method (30) for determining map data according to any one of claims 1 to 9.

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