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

Abstract

The present 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: determining (S30) a first set of map data associated with a geographical region, obtaining (S31) a single-operator network coverage map associated with an operator of the wireless communication network, determining (S33), based on the single-operator network coverage map, a second set of map data associated with a first geographical extension, obtaining (S34) a multi-operator network coverage map associated with a plurality of wireless communication network operators, determining (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 abstract: 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 in the event of roaming Technical field

[0001] The present invention belongs to the field of connected vehicles, and more particularly relates to a method and a server for determining cartographic 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. Because traffic conditions vary, autonomous vehicles cannot rely solely on on-board road maps, but must instead continuously download up-to-date map data.

[0003] In order 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 enable 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 territory is rarely homogeneous, in terms of access technology or signal strength. Consequently, during a journey, a vehicle does not benefit from a constant flow rate to download map data from a server. In particular, there are geographical areas without network coverage, called "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 white zone (see for example patent application FR 3106686 A1). To do this, the geographical areas without network coverage are referenced on a network coverage map so that all the map data associated with the white zone are preloaded when the vehicle approaches it.

[0006] However, white zones may vary from one operator to another. Thus, the vehicle may consider that it is about to enter a white zone for the operator of the wireless communication network to which it is connected, and thus preload a lot of map data, while this geographical area is not white for another wireless communication network, operated by another operator, to which the vehicle can possibly connect in the case of roaming agreements.

[0007] For example, a vehicle may travel from a first country to a second country, initially being connected to the communications network of a first operator. If this first operator does not serve the second country, then the second country will be considered as corresponding to a large white zone by the vehicle which will preload a large amount of map data whereas a second operator, with which there may be roaming agreements, may serve this second country and could provide the vehicle with map data in this second country without having to preload it via the wireless communications network of the first operator. However, the switch from the first operator to the second operator may take time, so that access to the map data for the second country is not immediate. Disclosure of the invention

[0008] The present invention aims to overcome all or part of the limitations of the solutions of the prior art, in particular those set out above, by proposing a solution which makes it possible to improve the consideration of geographical areas without network coverage. In particular, the present invention aims to make it possible to limit the quantity of preloaded map data for geographical areas served by operators other than a current operator of a communication network to which the vehicle is connected, while ensuring continuity in the availability of the map data if a switch from one operator to another is necessary (roaming).

[0009] To this end, it proposes according to a first aspect a method of 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 map associated with an operator of the wireless communications network to which the vehicle is connected, known as the “current operator”, - a determination of a second set of cartographic data associated with a first geographical extension of the geographical region and without network coverage based on 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 based on 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 information for the vehicle's current operator's wireless communications 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 of the current operator, and the multi-operator network coverage map makes it possible to determine whether geographical areas without network coverage of the current operator are served by other operators which could be used to download map data (subject to roaming agreements).

[0012] It should be noted that, by "without 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 possibly established is not suitable for downloading map data (for example due to insufficient throughput, or limited to making emergency calls, etc.).

[0013] Generally, the method for determining cartographic data provides for selecting a first set of cartographic data which corresponds to the basic cartographic data, chosen independently of any consideration of network coverage, which concerns a geographic region around a point of interest.

[0014] The method for determining cartographic data also provides for selecting a second set of cartographic 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 cartographic data to be preloaded before the vehicle moves in the first geographical extension which is a white zone (i.e. without network coverage) for the current operator. It should be noted that this second set of map data is selected independently of the multi-operator network coverage map, i.e. independently of whether another operator is available in the first geographical area. Such arrangements make it possible to preload map data including for a geographical area, without network coverage for the current operator, in which a switch to another operator is likely to occur. Since such a switch can take time, the map data for the geographical area in which the switch occurs are therefore preloaded in advance, before a connection can be established there with the wireless communication network of this 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 preloaded before losing connection with the current operator's wireless communication network and before establishing 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 also has no network coverage for the other operators, so that it is unlikely to be able to switch to another operator there.

[0016] Thus, the quantity of selected map data is greater (due to the addition of the third set) if the probability of being able to reestablish a connection by switching to another operator is low, which makes it possible to increase the duration of availability of the service. Conversely, the quantity 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 makes it possible to improve the availability of the map data in the event of a switch 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 quantity of map data to be preloaded is also limited in the event of a switch, since the third set of map data is then not selected.

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

[0019] In particular embodiments, 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 and within a first geographic neighborhood around the geographic region.

[0020] In particular embodiments, 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 geographic region and outside the first geographic neighborhood and inside a second geographic neighborhood around the first geographic neighborhood.

[0021] In particular embodiments, a geographic area is considered to be without network coverage according to the multi-operator network coverage map if no operator serves said geographic 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 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%. A tile corresponds to the cartographic data associated with a given geographical area, and a country corresponds to the union of a plurality of such geographical areas.

[0025] In particular embodiments, the method for determining cartographic data comprises receiving an identifier of the current operator, transmitted by the vehicle, and the single-operator network coverage map is determined as a function of the identifier received.

[0026] In particular embodiments, the method for determining cartographic data comprises a transmission, via the wireless communication network and to the vehicle, of all or part of the cartographic data of 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 geographic region includes a border geographic area without network coverage according to the single-operator network coverage map, the first geographic extension extending the geographic region from this border geographic area without network coverage.

[0029] In particular embodiments, the third set of cartographic data is determined when the first geographic extension comprises a border 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, the second geographic extension extending the first geographic extension from this border geographic area without network coverage.

[0030] According to a second aspect, there is provided a computer program product 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 cartographic data according to any one of the embodiments of the present disclosure.

[0031] According to a third aspect, there is provided 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 for determining cartographic data according to any of the embodiments of the present 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 cartographic data according to any one of the implementation modes of the present disclosure. Presentation of figures

[0033] The invention will be better understood on 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 realization of a server 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 cartographic data selected in the event that there are no geographical areas without network coverage, - [Fig.5] [Fig.5]: a schematic representation of cartographic data selected based on geographical areas without network coverage, in the event that a switch to another operator is considered possible, - [Fig.6] [Fig.6]: a schematic representation of cartographic data selected based on geographic areas without network coverage, in the event that a switch to another operator is not considered possible.

[0034] In these figures, identical references from one figure to another designate identical or similar elements. For reasons of clarity, the elements shown are not to scale, unless otherwise indicated.

[0035] Furthermore, the order of steps shown in these figures is given solely as a non-limiting example of the present 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 embodiments

[0036] [Fig. 1] schematically represents a vehicle 10, for example a motor vehicle, which is moving on a road of 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 hereinafter referred to 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 core network 12, to a server 20, in order to obtain cartographic data which can be used in particular for the purposes of assisting in driving the vehicle 10 (alert, navigation, autonomous guidance, etc.).

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

[0039] As illustrated by [Fig. 2], the server 20 also comprises a processing circuit 21. The processing circuit 21 comprises, 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 hardware-distinct equipment communicating with each other. The processing circuit 21 also comprises one or more memories 211 (magnetic hard disk, electronic memory, optical disk, 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 method 30 for determining cartographic data which will be described below.

[0040] As illustrated by [Fig. 2], the server 20 also comprises a communication module 22 adapted to exchange data with other devices, in particular with the vehicle 10 (via the wireless communication network and, where appropriate, 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] Via the communication module 22, the server 20 is adapted to receive requests from the vehicle 10 and to transmit in return information on cartographic data considered to be relevant to the request from the vehicle 10.

[0042] [Fig. 1] also represents a geographical area 13 which is not covered by the wireless communication network of the current operator. This geographical area is hereinafter referred to as “without network coverage” or “white zone” for the current operator. As indicated above, a geographical area without network coverage (or white) for a given wireless communication network corresponds to a geographical area in which it is not possible to connect to this wireless communication network, or in which the connection is possible but is 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 that 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 geographical position of the vehicle 10. In such a case, the request from the vehicle 10 aims to obtain cartographic data around its current geographical position. Regarding the current geographical position of the vehicle 10, the latter is connected to the wireless communication network and the current geographical position of said vehicle 10 is therefore under network coverage. In such a case, the point of interest is for example received by the server 20, for example in a request for cartographic data sent by the vehicle 10 and received directly or indirectly by the server 20.

[0047] According to another example, the position 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 for example received by the server 20, for example in a request for cartographic data sent by the vehicle 10 and received directly or indirectly by the server 20. According to another non-limiting example, the point of interest can be determined by the server 20, for example as a function of 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 may also be determined by the server 20 if it receives the current geographic position of the vehicle 10 and the geographic position of the desired destination of the vehicle 10.

[0048] It should be noted that the determination of cartographic data to be transmitted to the vehicle 10 is for example carried out in response to the reception of a request for cartographic data sent by the vehicle 10 and received directly or indirectly by the server 20. However, it is also possible to determine such cartographic data in a recurring manner, for example periodically, depending 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 comprises a step S30 of determining a first set of cartographic data associated with a geographic region around the point of interest of the vehicle 10.

[0050] For example, the 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). According to 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 (for example according to longitude) and ordered (for example according to latitude) and if the tile associated with the geographic area in which the point of interest is located corresponds to the indexed tile ( and mo being integers), then the first set of map data graphics corresponds for example to the set of tiles whose indexes ( / 2, m ) (n and m being integers) are such that n®-N < n < n0 + N and -M <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 comprises 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 cartographic data comprises a step of reception (not shown in the figures), by the server 20, of an identifier of the current operator and the single-operator network coverage map is determined as a function of the identifier received. For example, the identifier of the current operator is received in the form of an MCC / MNC pair (for “Mobile Country Code / Mobile Network Code”). However, any format of identifier of the current operator can be implemented in the present disclosure, and the choice of a particular format constitutes only a variant, in no way limiting, of implementation of the present disclosure.The identifier of the current operator is for example emitted by the vehicle 10, or is emitted by the wireless communication network of the current operator, in order to allow the server 20 to obtain the single-operator network coverage map associated with the current operator of the vehicle 10. More generally, any means making it possible to identify the single-operator network coverage map to be used can be implemented and the choice of a . This particular means constitutes 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 database remote from the server 20.

[0054] As illustrated by [Fig.3], the method 30 for determining cartographic data comprises 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, step S33 of determining the second set of map data may be executed systematically, but may however 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], step S33 of determining the second set of map data is executed under conditions, and the method 30 for determining map data comprises a step S32 for evaluating whether the geographic region intersects a geographic area without network coverage according to the single-operator network coverage map. In this example, the step S33 for determining the second set of map data is executed when it is determined that the geographic region (represented by the first set of map data) has a border geographic area without network coverage according to the single-operator network coverage map (reference S32a in [Fig. 3]).Where appropriate, the first geographic extension is for example obtained by extending the geographic region from this border geographic area without network coverage, by grouping together the geographic areas without network coverage and by incorporating the associated tiles into the second set of cartographic data. In this example, step S33 of determining the second set of cartographic data is not executed when the geographic region does not include a border geographic area without network coverage according to the single-operator network coverage map (reference S32b in [Fig. 3]).

[0057] As its name indicates, the first geographical extension is obtained by grouping together geographical areas, without network coverage according to the single-operator network coverage map, located outside the geographical region. Such a geographical extension of the geographical region is, in preferred embodiments of implementation, limited in space in order to limit 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 geographical area without network coverage for the current operator, while waiting for a switch to another operator to be carried out if this geographical area is served by another operator. The dimensions of the first geographical extension are therefore advantageously determined to allow the vehicle 10 to have map data for the entire journey that it is likely to make in a geographical area without network coverage for the current operator before a switch 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 first predetermined geographic neighborhood around the geographic region. For example, the first geographic neighborhood may be formed by the geographic areas located at a distance from the point of interest that is less than a first predetermined maximum distance (where appropriate greater than the maximum distance considered to determine the geographic region and the first set of cartographic data). According to another example, if the tiles are indexed on the abscissa and ordered, as presented above, then the first geographic neighborhood corresponds for example to the set of geographic areas associated with the tiles whose indexes ( / 7, / 77 ) are such that ( - N - <n< Hq - N ) et (nQ + N <n< / Iq + N + Nl) et (mQ-M-Ml < m < m0-M ) et ( m{y + M < m < + M + M] ) expressions in which N 1 and Mj are integers predetermined that define the first predetermined geographic neighborhood to be considered. For example, in the case where a tile is associated with a substantially square geographic area of ​​2 km on each side, it is possible to have Ny — M} = 10. According to another example, it is possible to extend the geographic region, starting from a border geographic area without network coverage of said geographic region, by propagating iteratively from a border geographic area without network coverage to each of the neighboring geographic areas without network coverage. In other words, the first geographic extension, initially empty, is enlarged iteratively, for example until reaching a predetermined maximum number of iterations (for example 10 iterations maximum).So, during the first iteration, the first geographic extent is enlarged by adding all the geographic areas without network coverage that are located outside the geographic region and that are contiguous to the border geographic area without coverage. network of the geographic region. During the second iteration, the extension continues in the same way from the border geographic areas without network coverage of the first geographic extension obtained in the previous iteration, etc.

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

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

[0061] Generally, the multi-operator network coverage map provides network coverage indications that relate to the wireless communication networks of several different operators. As such, the multi-operator network coverage map aims to enable the server 20 to assess whether there exists, in a geographical area without network coverage for the current operator, at least one operator for which this geographical area is under network coverage. The multi-operator network coverage map therefore enables the server 20 to assess the probability that a switch to another operator may occur in a geographical area without network coverage for the current operator. It should be noted, however, that such a switch is generally only possible in the case of roaming agreements between the current operator and the other operator.If the server 20 has information on existing roaming agreements, then it may be possible to determine precisely whether such a switch is possible in a given geographical area. If the server 20 does not have information on existing roaming agreements, but only on network coverage by other operators, then it is only possible to evaluate whether other operators serve a geographical area without network coverage for the current operator, without determining with certainty whether such a switch is actually possible there.

[0062] For example, the multi-operator network coverage map may comprise a plurality of layers, each layer corresponding to a network coverage map. single-operator network coverage map associated with a given operator. Where appropriate, the single-operator network coverage map of the current operator may, in certain cases, be one of the layers of the multi-operator network coverage map. In the case where the multi-operator network coverage map comprises a plurality of layers associated with different operators, and if the server 20 has information on roaming agreements, then it is possible to identify the layers corresponding to the other operators having a roaming agreement with the current operator. If the 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] According to other examples, the multi-operator network coverage map may consist of a layer that synthesizes the network coverages of different operators. In such a case, the multi-operator network coverage map does not allow the individual network coverages of each operator to be traced back. In the remainder of the description, the case where the multi-operator network coverage map provides, for each geographical area, a summary of the network coverages of different operators is considered in a non-limiting manner.

[0064] According to a first example, the multi-operator network coverage map is constructed so that a geographical area is considered to be without network coverage if no operator serves this geographical area. Consequently, such a geographical area is considered to be under network coverage if it is served by at least one operator. Such an approach is optimistic with respect to the evaluation of 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 is under network coverage for at least one operator.

[0065] According to another example, the multi-operator network coverage map is constructed so that a geographical area is considered to be without network coverage if at least one major operator of a country to which said geographical area belongs does not serve said geographical area. Consequently, such a geographical area is considered to be under network coverage only if it is served by all the major operators of the country. Such an approach is pessimistic with respect to the evaluation of 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 is without network coverage for a major operator of the country.

[0066] According to another example, the multi-operator network coverage map is constructed so that a geographical area is considered to be without network coverage if no major operator of the country to which said geographical area belongs serves this geographical area. Consequently, such a geographical area is considered to be under network coverage if it is served by at least one operator major operator of the country in which the said geographical area is located. Such an approach is therefore intermediate compared to the previous approaches with regard to the evaluation of 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 is under network coverage for at least one major operator in the country.

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

[0068] According to another example, the server 20 can estimate which operators are the major operators in a country from single-network network coverage maps of each operator. For example, the server 20 can determine for a given country, which geographical areas (tiles) correspond to this country. Then an operator can be considered to be a major operator in this country if it has network coverage in many geographical areas of this country. To determine whether an operator is a major operator in a country, it is advantageous to discard the 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 tiles in the country in which 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 comprises a plurality of layers, each layer corresponding to a single-operator network coverage map associated with a given operator. Where appropriate, to check 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 database remote from the server 20.

[0071] As illustrated by [Fig.3], the method 30 for determining cartographic data comprises a step S36 for determining a third set of map data associated with a second geographic extension of the first geographic extension, said second geographic 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, step S36 of determining the third set of map data may be executed systematically, but may however result in a third set of map data which 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 by [Fig. 3], step S36 of determining the third set of map data is executed under conditions, and the method 30 for determining map data comprises a step S35 of evaluating whether the first geographical extension intersects a geographical 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 executed when it is determined that the first geographical extension (represented by the second set of map data) comprises 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 (reference S35a in [Fig. 3]).Where appropriate, the second geographic extension is for example obtained by extending the first geographic extension from this border geographic area without network coverage, by grouping together the geographic areas without network coverage (which are neither in the geographic region nor in the first geographic extension) and by incorporating the associated tiles into the third set of map data. In this example, step S36 of determining the third set of map data is not executed when the first geographic extension does not include a border geographic 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 geographical extension is obtained by grouping together geographical areas, without network coverage according to the single-operator network coverage map and the multi-operator network coverage map, located outside the first geographical extension (and outside the geographical region). Such a geographical extension of the first geographical extension is, in particular modes of implementation, limited in space in order to limit the amount of map data to be included in the third set.

[0075] For example, the second geographic extension is obtained by grouping geographic areas that are located outside the geographic region and outside the first geographic extension, but within a second predetermined geographic neighborhood around the first geographic neighborhood. For example, the second geographic neighborhood may be formed by the geographic areas located at a distance from the point of interest that is less than a second predetermined maximum distance (where appropriate greater than the first maximum distance considered to determine the first geographic extension). According to another example, if the tiles are indexed on the abscissa and ordered, as presented above, then the second geographic neighborhood corresponds for example to the set of geographic areas associated with the tiles whose indexes ( n.m ) are such that ( - N - N-, < n < Hq - N ( ) and ( n0 + Æj < n < n0 + N{ + N2 ) and ( m() - - M2 < m < mQ - M i ) and . ( m0 + M^ < m < + M2 ) expressions in which and M2 are predetermined integers that define the second predetermined geographical neighborhood to be considered. For example, in the case where a tile is associated with a substantially square geographical area of ​​2 km on each side, it is possible to have N2 = M2 =10. According to another example, it is possible to extend the first geographical extension, starting from a border geographical area without network coverage of said first geographical extension, by propagating iteratively from a border geographical area without network coverage to each of the geographical areas without network coverage which are neighbors to it. In other words, the second geographical extension, initially empty, is enlarged iteratively, for example until reaching a predetermined maximum number of iterations (for example 10 iterations maximum).Thus, during the first iteration, the second geographic extent is enlarged by adding all the geographic areas without network coverage that are located outside the first geographic extent (and outside the geographic region) and that are contiguous to the border geographic area without network coverage of the first geographic extent. During the second iteration, the extension continues in the same way from the border geographic areas without network coverage of the second geographic extent obtained in the previous iteration, etc.

[0076] It should be noted that it is also possible, in certain embodiments, 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). Where appropriate, it is however possible to optionally consider a constraint in terms of the quantity of map data graphics, for example ensuring that the number of tiles determined does not exceed a predetermined maximum number.

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

[0078] The cartographic data determined by the server 20 (first set and, where appropriate, the second set and possibly the third set) correspond to cartographic data that the server 20 considers to be relevant with respect 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 may be directly transmitted to the vehicle 10 by the server 20. According to another example, the map data thus determined are for example proposed to the vehicle 10 before being transmitted. In other words, the server 20 may transmit to the vehicle 10, as a recommendation, a list of the determined map data, and the vehicle 10 may decide to download all the map data indicated in the list (first set and, where appropriate, the second set and possibly the third set) or it may decide to reject them in whole or in part. For example, the vehicle 10 may decide to limit the quantity of tiles downloaded to a predetermined maximum number of tiles among the tiles recommended by the server 20.

[0080] In the non-limiting example illustrated by [Fig. 3], the method 30 for determining cartographic data comprises a step S37 of transmitting, via the wireless communication network and to the vehicle 10, all or part of the determined cartographic data (first set and, where appropriate, second set and possibly third set of cartographic data). This transmission is carried out via the wireless communication network of the current operator, before the vehicle 10 enters a white zone.

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

[0082] In the case where the server 20 is responsible for the transmission of cartographic data to the vehicle 10, these are for example obtained from a memory 211 of said server 20, in which said cartographic data have been previously stored, or from a database remote from the server 20.

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

[0084] In the example illustrated by [Fig. 4], the geographical area in which the point of interest is located is represented with a black fill, and the first set of map data corresponds to the tiles associated with the geographical areas located around the geographical area in which the point of interest is located (including the tile associated with the geographical area in which the point of interest is located). The grouping of these geographical areas forms the geographical region RG associated with the map data of the first set. In the example illustrated by [Fig. 4], the geographical region RG does not include a geographical area without network coverage, so that step S33 of determining the second set and step S36 of determining the third set are not executed. The map data determined by the server 20 are in this example limited to the data of the first set of map data.

[0085] [Fig.5] schematically represents the geographical areas associated with the cartographic data determined by the 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 geographical areas (tiles) of the geographical region RG associated with the cartographic data of the first set. As illustrated by part a) of [Fig.5], the geographical region RG comprises border geographical areas which 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]). Consequently, step S33 of determining the second set is executed.

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

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

[0089] Part a) of [Fig.6] schematically represents the geographical areas (tiles) of the geographical region RG associated with the cartographic data of the first set. As illustrated by part a) of [Fig.6], the geographical region RG comprises border geographical areas which 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.6]). Consequently, step S33 of determining the second set is executed.

[0090] Part b) of [Fig. 6] schematically represents the geographical areas (tiles) of the geographical region RG associated with the cartographic data of the first set, as well as the geographical areas (tiles) of the first geographical extension EG1 associated with the cartographic data of the second set. In the example illustrated by part b) of [Fig. 6], the first geographical extension EG1 is for example determined in a first predetermined geographical neighborhood VG1 around the geographical region RG, and a part of the white zone ZB for the current operator is located outside of said first geographical 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 multi-operator network coverage map, so that a switch to another operator is not considered possible in the white zone ZB.Therefore, step S36 of determining the third set is executed.

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

[0092] In the example illustrated by [Fig.6], the cartographic data determined by the server 20 therefore includes the cartographic data of 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 reestablish 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, cartographic data is nevertheless determined (second set) to improve the availability of the cartographic data while the switch can be carried out.

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

Claims

Claims

1. Method (30) 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 (S30) of a first set of cartographic data associated with a geographical region around a point of interest for the vehicle, - an obtaining (S31) of a single-operator network coverage map associated with an operator of the wireless communication network to which the vehicle is connected, called the "current operator", - a determination (S33) of a second set of cartographic data associated with a first geographical extension of the geographical region and without network coverage based on the single-operator network coverage map, - an obtaining (S34) of a multi-operator network coverage map associated with a plurality of wireless communication network operators,- 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.,

2. The method (30) of claim 1, wherein 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 and within a first geographic neighborhood around the geographic region.

3. The method (30) of claim 2, wherein 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 geographic region and the first geographic neighborhood and inside a second geographic neighborhood around the first geographic neighborhood.

4. A method (30) according to any preceding claim, wherein a geographic area is considered to be without network coverage based on the multi-operator network coverage map if no operator serves said geographic area.

5. 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 of a country to which said geographical area belongs does not serve said geographical area.

6. 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. The method (30) of 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. Method (30) according to any one of the preceding claims, comprising a reception of an identifier of the current operator, transmitted by the vehicle, and in which the single-operator network coverage map is determined as a function of the identifier received.

9. Method (30) according to any one of the preceding claims, comprising a transmission, via the wireless communication network and to the vehicle, of all or part of the map data of the first set, the second set and the third set.

10. A method (30) according to any preceding claim, wherein the point of interest corresponds to a geographic position of the vehicle or to a geographic position of a point remote from the vehicle, located on a planned path of the vehicle.

11. Computer program product 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 cartographic data according to any one of the preceding claims.

12. A computer-readable recording medium having recorded thereon 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 cartographic data according to any one of claims 1 to 10.

13. Server (20) comprising at least one processor and at least one memory, configured to implement a method (30) for determining cartographic data according to any one of claims 1 to 10.

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