DE102018219592A1 - Procedure for creating a coverage map - Google Patents

Abstract

The invention relates to a method for creating a coverage map in a mobile device, the coverage map being divided into tiles (12, 14) and passive data for at least some of the tiles (12, 14) being measured for at least one signal characteristic for at least one service, and using a model, the passive data is converted into information relating to a data rate of the respective service, this information being connected to the assigned card.

Description

The invention relates to a method for creating a cover card and an arrangement for performing the method.

State of the art

A coverage map is a map of a specific geographic area that contains network coverage information. This information provides information as to whether and if so to what extent services that are offered wirelessly are available. A breakdown by different services can be given. These services can then be assigned data rates or statistical distributions of data rates. Ambient conditions such as weather conditions can also be taken into account.

The coverage map is typically divided into so-called tiles. These usually represent areas in the region shown by the map that lie next to each other and do not overlap. Each tile is then assigned at least one data rate or at least one statistical distribution of a data rate for at least one service in the coverage map. On the basis of this cover map, the user can then estimate or even determine in which of the geographical areas he can use which services. If necessary, this can also be taken into account when choosing the route.

From the publication US 2006 021 142 A a method for determining the transmission quality at different locations within geographic areas covered by the transmission signal is known. Data is generated in a mobile device that represents a relative signal quality at different locations within the geographical area. The data is stored and processed in the device to define areas of poor signal quality in at least a portion of the geographic area in which the device is moving. The data that is stored is transmitted from time to time to a central transmission system.

The publication US 2015 020 140 A describes a digital transceiver with a receiving unit that receives a signal. A signal strength detection unit is also provided, which detects the strength of the received signal.

A disadvantage of existing approaches is that user data is saved from a central database and therefore protection of the user's privacy cannot be fully guaranteed. In addition, the user or his movements can be easily tracked. Known methods furthermore require that a detected signal strength be connected to the detected locations. This requires a large amount of memory.

Disclosure of the invention

Against this background, a method for creating a cover map according to claim 1 and an arrangement for performing the method according to claim 11 are presented. Embodiments result from the dependent claims and from the description.

The method presented provides for the cover map to be stored or stored exclusively on the part of the user, for example in the vehicle, so that it is ensured that user information, for example information that indicates where the user is or is located are moved, secured and no one is aware of it. The coverage map is therefore not stored in or with a central database, where a large number of stores or data are stored.

This change compared to known methods requires that a new type of connection of the acquired passive data, for example the acquired signal strength information, must be found with the acquired location, since the current methods require a large amount of memory for this. These passive data relate to a signal characteristic and can, for example, relate to the signal strength but also to a bandwidth. The signal strength is dealt with in the following, although this is not intended to limit the method to these passive data.

Passive data or parameters are parameters for the determination of which no data transmission is necessary. These are, in particular, parameters that can be read by a cellular modem, such as signal strengths (e.g. SINR, RSRP, ...).

1. 1. Speichern nur eines Werts für jeden Dienstanbieter in Abhängigkeit von Modellen, andere Variablen können berechnet werden.
2. 2. Ähnliche Kacheln werden miteinander verbunden, wenn sie ein ähnliches Verhalten haben.
3. 3. Es ist nicht erforderlich, dass ein Wert für jeden Dienstanbieter in jeder Kachel für den Fall gespeichert wird, dass eine Relation zwischen den zuvor gespeicherten Werten für die verschiedenen Dienstanbieter in benachbarten Kacheln hergestellt werden kann.
4. 4. Es ist nicht erforderlich, einen Wert zu speichern, für den Fall von ländlichen und städtischen Bereichen, wo Signalausbreitungsmodelle existieren. Indem die Modelle verwendet werden, können die erwarteten und berechneten Werte für eine Kachel verglichen werden, wenn die Werte gleich sind; keine Werte für die Kachel müssen gespeichert werden, lediglich die Information, dass für diese Kachel das physikalische Modell anwendbar ist, ist zu speichern.

The connection mentioned can be carried out, for example, in the following steps:

1. 1. Store only one value for each service provider depending on models, other variables can be calculated.
2. 2. Similar tiles are connected if they behave in a similar way.
3. 3. It is not necessary to store a value for each service provider in each tile in case there is a relation between the previously saved values for the different service providers can be produced in neighboring tiles.
4. 4. There is no need to store a value in the case of rural and urban areas where signal propagation models exist. By using the models, the expected and calculated values for a tile can be compared if the values are the same; no values for the tile have to be saved, only the information that the physical model can be used for this tile has to be saved.

1. 1. einen mobilen Signalstärkedetektor,
2. 2. ein Modell, das die erfassten Signalstärkeparameter zu einer verfügbaren Datenrate wandelt, wobei mit Hilfe des Modells Netzwerkqualitätsindikatoren geschätzt werden,
3. 3. einen Positions- bzw. Lagedetektor,
4. 4. ein Verbinden der erfassten Werte der Signalstärkeparameter mit dem erfassten Ort.

The mobile signal coverage card requires four main steps or components:

1. 1. a mobile signal strength detector,
2. 2. a model which converts the recorded signal strength parameters to an available data rate, network quality indicators being estimated with the aid of the model,
3. 3. a position or position detector,
4. 4. connecting the detected values of the signal strength parameters to the detected location.

The model mentioned is based on the idea of applying a type of machine learning to a large amount of data that cannot easily be stored in the vehicle in order to generate the model. The model is then stored in the vehicle and used there to obtain data rates for measurements of passive parameters.

The model can be, for example, an already trained neural network. Alternatively, CCDFs (Complementary Cumulative Distribution Functions) can be used. This gives you a kind of look-up table for mapping signal strengths to data rates.

• Im Vorfeld wird eine große Menge passiver Parameter zusammen mit Datenraten gesammelt. Diese sind notwendig, um das Modell aufzustellen.

A brief summary of the model based on CCDFs is given below:

• In advance, a large amount of passive parameters are collected together with data rates. These are necessary to set up the model.

1. 1. Die passiven Parameter werden in Wertebereiche unterteilt.
2. 2. Für jeden der Bereiche wird eine CCDF der in dem Bereich enthaltenen Datenraten erstellt.
3. 3. Als Modell werden die Bereiche mit zugeordneten CCDFs gespeichert. Alternativ: Statt den CCDFs selbst wird eine Funktion ermittelt, die die CCDF näherungsweise beschreibt.

Determination of the model:

1. 1. The passive parameters are divided into value ranges.
2. 2. A CCDF of the data rates contained in the area is created for each of the areas.
3. 3. The areas with assigned CCDFs are saved as a model. Alternatively: Instead of the CCDFs themselves, a function is determined that describes the CCDF approximately.

1. 1. Der Wertebereich, in dem die Signalstärke liegt, wird bestimmt und die zugehörige CCDF ausgewählt.
2. 2. Ein bestimmtes Perzentil, z. B. 0.75, wird verwendet, um von der ausgewählten CCDF eine Datenrate abzulesen.
3. 3. Die somit bestimmte Datenrate wird als geschätzte Datenrate für den Signalstärkewert verwendet.

Using the model to get a data rate for a signal strength:

1. 1. The range of values in which the signal strength lies is determined and the associated CCDF is selected.
2. 2. A certain percentile, e.g. B. 0.75 is used to read a data rate from the selected CCDF.
3. 3. The data rate thus determined is used as the estimated data rate for the signal strength value.

If there are several measured signal strengths for a tile, a prediction is made for each signal strength and the median is formed from the predictions.

To vary how likely the prediction is exceeded, the percentile can be varied. The goal is to predict a data rate that will be exceeded as often as possible, since an exact forecast is not possible. The higher the percentile, the more pessimistic the prediction and the higher the probability that the actually achievable data rate is higher than the prediction.

The coverage map required for this purpose, especially with current methods, requires a large amount of memory, which is not feasible when all the data is stored in the vehicle. Another way of storing signal strength data is therefore required. A new procedure for connecting the detected signal strength to the detected location of the user is thus also presented, which requires less storage space.

The method presented aims to represent the location map in tiles, so that the map is divided into a number of tiles. It is also possible to control the number of tiles required depending on how large the tile should be to cover a convenient area for the cover card. A mobile device is also provided that continuously measures the signal strength as it moves to an active interface. The data is then passed to a data rate determination model, which is a predefined model that is responsible for covering the acquired signal strength parameters in an available data rate value. The mobile device includes a position or location detection component, which is responsible for informing the vehicle in which tile it is currently located. Then the acquired signal strength parameter value is stored in this specific tile under this specific interface.

• Die Privatsphäre des Nutzers kann besser geschützt werden und es wird schwieriger, den Nutzer nachzuverfolgen. Die erforderliche Speicherkapazität wird verringert, so dass sie in eine verfügbare mobile Vorrichtung bzw. eine Fahrzeug-Hardware passt.

The method presented has the following advantages over known methods:

• The user's privacy can be better protected and it becomes more difficult to track the user. The required storage capacity is reduced so that it fits into an available mobile device or vehicle hardware.

Further advantages and refinements of the invention result from the description and the accompanying drawings.

It goes without saying that the features mentioned above and those yet to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own without departing from the scope of the present invention.

Figure list

• 1 shows tiles in a world map according to NDS (Navigation Data Standard).
• 2nd shows a map, which is divided into tiles.
• 3rd shows a possible execution of the presented method in a flow chart.

Embodiments of the invention

The invention is shown schematically in the drawings using embodiments and is described in detail below with reference to the drawings.

1 shows a world map, the total with the reference number 10th is designated and which is in a number of tiles 12 , 14 is divided. The map complies with the NDS, a widely used standard for map display. The map shows two different levels of tiles 12 , 14 , namely level 0 Tiles 12 and level 1 Tiles 14 , where level 0 Tiles 12 a larger area than level 1 Tiles 14 cover and are therefore less detailed.

2nd shows a map 20th that come in a variety of tiles 22 is divided. Each of these tiles 22 can be assigned a statistical distribution of a data rate to one service or statistical distributions to data rates of several services. This then results in the coverage map, which can be created according to the method presented herein. 2nd shows information similar to 1 , only with the exact sizes of the different tile levels.

3rd shows in a flowchart a possible sequence of the described method. In a first step 50 starts the process. Then in a second step 52 carried out a position detection and in a third step 54 , substantially simultaneously, a signal strength detection is carried out. Then there is a further step 56 connecting the current position to a map tile. Then takes place in one step 58 checking whether a value has already been saved for this tile. If this is not the case, then in one step 60 the value stored in the database. If this is the case, then in one step 62 an EMA (Exponential Moving Average) applied. With one step 64 the procedure ends.

• Wenn eine digitale Sende-Empfangsvorrichtung bewegt wird, wird sie Bereiche durchqueren, in denen ein ausreichendes mobiles Signal zu empfangen ist, und auch Bereiche, in denen das Signale nicht ausreichend oder sogar überhaupt kein mobiles Signal verfügbar ist. Es ist dann unmöglich, ein mobiles Signal zu empfangen, wenn diese Schnittstelle bzw. dieser Kanal verwendet wird. Es wird daher eine Vorgehensweise dargestellt, bei der eine Abdeckungskarte entwickelt werden kann, die Informationen zu den Zuständen des mobilen Signals an verschiedenen Orten trägt, was vorab zeigen kann, wie der Signalzustand für die spezifische Schnittstelle sein wird. Die Signalzustandsinformation kann dann von der mobilen Einrichtung bzw. dem Fahrzeug verwendet werden, um automatisch die optimale Schnittstelle an diesem Ort auszuwählen. Es wird hier angenommen, dass die mobile Einrichtung bzw. das Fahrzeug verschiedene Schnittstellen zur selben Zeit unterstützt, bspw. WLAN 3G, 4G, 5G oder dieselbe Mobiltechnologie, aber von zwei oder mehreren verschiedenen Dienstanbietern zur selben Zeit.

The method presented for creating a coverage map and the described arrangement for carrying out the method are discussed in more detail below:

• When a digital transceiver is moved, it will traverse areas where a sufficient mobile signal can be received, as well as areas where the signal is insufficient or even no mobile signal is available. It is then impossible to receive a mobile signal if this interface or channel is used. A procedure is therefore presented in which a coverage map can be developed which carries information on the states of the mobile signal at different locations, which can show in advance what the signal state will be for the specific interface. The signal status information can then be used by the mobile device or the vehicle to automatically select the optimal interface at this location. It is assumed here that the mobile device or the vehicle supports different interfaces at the same time, for example WLAN 3G, 4G, 5G or the same mobile technology, but from two or more different service providers at the same time.

The information provided by the coverage map serves to increase the experience and the quality of the service by constantly trying to select the optimal interface for the current location.

The method described here is based on a representation of the location map in tiles. For example, the world map can be divided into a number of tiles. The number of tiles required depends on how large the tile should be to cover an appropriate area for the coverage map.

Instead of making a single large image, a tile map will divide the image into several smaller images, that is, tiles of a fixed size. When the map is displayed, only the images covering the current geographic area are required. With a map divided into tiles there is a limited but possibly very high number of possible tiles. This means that all tiles can be prepared in advance and can be temporarily saved if requested. The processing can be carried out very efficiently.

It is not necessary to show the map of the whole world. The current country or state can be sufficient and then one can start dividing the map of this limited area into a specific number of tiles of similar size based on the possible storage space.

A tiled map consists of a number of magnification levels, each magnification level being a map of the same geographic area but drawn at different scales, divided into tiles, each tile being the same size regardless of the magnification level. Increasing the scaling thus means increasing the size of the map in pixels, which in turn increases the number of tiles in the degree of enlargement. The size of the tile can be controlled based on the available memory and on the amount of details or data covered per tile, so that a balance must be weighed between the available memory and the maximum covered area per tile. The smaller the tile, the more accurate the coverage map information, but the higher the storage requirements.

The procedure of dividing the map into a specific number of tiles is also used in the Navigation Data Standard (NDS), which is a standardized format for navigation databases in the automotive sector and was developed jointly by vehicle manufacturers and suppliers.

• - Die Welt ist rekursiv unterteilt in Hälften, wobei in Level 0 2 * 1 Kacheln enthalten sind (östlich und westlich von Greenwich) und jede Kachel 180 * 180 Grad enthält.
• - Level 1 enthält 4*2 Kacheln, wobei jede der 2 Level-0-Kacheln in 4 Teile unterteilt ist.
• - Bei Level N umfasst jede Kachel 180.0/(2^level) Grade in jede Richtung.
• - NDS verwendet Level zwischen 1 und 15. In Level 15 ist bspw. die Kachelgröße 393 m * 305 m.
• - Für Kodierungskoordinaten wird ein Skalierungsfaktor angewendet, so dass 360° 2³² entspricht, um den gesamten Bereich von 32 Bit mit Vorzeichen versehenen ganzen Zahlen auszuschöpfen. n reichen von -180° bis +180° und Breiten von -90° bis +90°. Somit sind Koordinatenwerte im Bereich von -2³¹ <= × < 2³¹ für Längen und -2³⁰ <= y < 2³⁰ für Breiten. Dies bedeutet, dass für Breiten 31 Bit ausreichend sind, wobei der Schnittpunkt von Nullmeridian und Äquator fest ist bei der Koordinate X, Y = 0.0, wie dies in 1 gezeigt ist.
• - Für jedes niedrigere NDS-Level wird die Kachelanzahl um zwei Bits erhöht.
• - NDS definiert eine Kachel wie folgt: Wenn (x1, y1) die Süd-West-Ecke einer Kachel ist und (x2, y2) deren Nord-Ost-Ecke ist, dann sind alle Punkte (x, y) mit x1 <= x < x2 und y1 <= y < y2 eindeutig dieser Kachel zugeordnet.
• - Die Kachel-Kennung besteht aus der Levelzahl gefolgt von der Kachelzahl. Das physische Kodieren einer Kachel-Kennung packt beide Komponenten zusammen in einen 32-Bit-Wert.

This system provides:

• - The world is recursively divided into halves, with level 0 containing 2 * 1 tiles (east and west of Greenwich) and each tile containing 180 * 180 degrees.
• - Level 1 contains 4 * 2 tiles, whereby each of the 2 Level 0 tiles is divided into 4 parts.
• - At level N, each tile has 180.0 / (2 ^level ) degrees in each direction.
• - NDS uses levels between 1 and 15. In level 15, for example, the tile size is 393 m * 305 m.
• A scaling factor is used for coding coordinates, so that 360 ° 2 corresponds to ^{32 in} order to utilize the entire range of 32-bit signed integers. n range from -180 ° to + 180 ° and latitude from -90 ° to + 90 °. Thus coordinate values are in the range of -2 ³¹ <= × <2 ³¹ for longitudes and -2 ³⁰ <= y <2 ³⁰ for latitudes. This means that 31 bits are sufficient for latitudes, the intersection of the prime meridian and the equator being fixed at the coordinate X, Y = 0.0, as shown in 1 is shown.
• - For each lower NDS level, the number of tiles is increased by two bits.
• - NDS defines a tile as follows: If (x1, y1) is the south-west corner of a tile and (x2, y2) is its north-east corner, then all points (x, y) with x1 <= x <x2 and y1 <= y <y2 clearly assigned to this tile.
• - The tile identifier consists of the level number followed by the tile number. The physical encoding of a tile identifier packs both components together into a 32-bit value.

• - Kachelgröße = 180°/2^level [Grad]
• - Kachel y = Betrag ((Breite + 90°)/Kachelgröße)
• - Kachel x = Betrag ((Länge + 180°)/Kachelgröße)

The number of tiles can be calculated based on a given coordinate and the level:

• - tile size = 180 ° / 2 ^level [degrees]
• - Tile y = amount ((width + 90 °) / tile size)
• - Tile x = amount ((length + 180 °) / tile size)

In the presented method, a system can be used that is similar to NDS, but with minor changes, in order to adapt it to the goals aimed at here. As explained above, the smallest level is given by NDS level 15, at which the tile size is 393 mx 305 m, which can be very large for the purposes aimed at here. After testing different tile sizes, a tile with a tile size of 50 mx 50 m shows reliable results because measurements at this distance have similar properties. This means that more than 15 levels may be required in the process. NDS uses a maximum of 32 bits, which supports up to 2 ³² different tiles. If the entire world is represented with a tile of 50 mx 50 m, more than 32 bits are required.

As mentioned above, the approach can only be used for a limited area. If, for example, Germany is represented with approximately 360,000 square meters, this includes Tile size 28 bits sufficient. As mentioned above, when smaller tile sizes are required, the system will zoom to the next lower level, which means that the tile number will increase by two bits. For example, two lower levels of magnification can be used with the 32-bit system.

Thus, the use of a specific magnification level means that a tile size of 50 mx 50 m ensures that a certain number of tiles is used and that each tile has a label. This identification identifies the tile and in particular which area is covered by the tile. The mobile device or vehicle knows in advance the degree of magnification used, and while it is moving, the current coordinates indicate longitude and latitude. The marking of the tile can be calculated accordingly.

1. 1. Referenzmessungen, die bereits in der Karte, geliefert von dem Kartenanbieter enthalten sind.
2. 2. Die Ausgangs- bzw. Anfangs-Karte wird mit Informationen geliefert, die den Ort bzw. die Position der Basisstationen und deren Sendeleistungsinformationen betreffen. Werden diese beiden Parameter verwendet, kann die Empfangsleistung bei verschiedenen Kacheln näherungsweise als Anfangswert berechnet werden.

As mentioned above, the method presented depends on storing information about the coverage map by the mobile device or the vehicle and not by a database of the service provider. This means that initially no signal condition measurements, ie measured by the vehicle, will be stored in the coverage map, but reference values can be stored in one of the two following ways:

1. 1. Reference measurements that are already included in the card supplied by the card provider.
2. 2. The initial or initial card is supplied with information relating to the location or position of the base stations and their transmission power information. If these two parameters are used, the reception power can be calculated approximately as an initial value for different tiles.

The card provider delivers the card with the initial tile distribution, with initial information being included for each tile. This information can relate to the exact location of the various base stations in relation to the tiles in addition to the transmission power of each of these base stations.

The initial information can also directly be the expected reception power for each tile. The card provider can have a reference vehicle that drives through different tiles and collects the reception power at different locations. The measurements vary from time to time, even at the exact locations, due to weather conditions, different degrees of reflection and due to a different number of users. Accordingly, the measurements collected by the card provider are only initial values that are used by the vehicle when it first drives through a certain tile.

If the base station location for the reference vehicle used by the card provider to collect the measurements is not exactly known, triangulation can be used to determine the base station location. A triangulation means that three measurements are made within the same tile and based on the variation in three measurements, and the location of the base station can be determined.

Triangulation can also be used to predict the received power measurement in the following tile if the following tile is covered by the same base station.

The mobile device or the vehicle starts moving while different interfaces are available to it, for example 4G from two different service providers and a WLAN interface. The mobile device continuously measures the various signal strength parameters as it moves for the current active interface. Signal strength parameters that are required for 4G are received power of the reference signal (RSRP), received reference signal qualities (RSRQ) and signal to interference noise ratios (SINR). Received signal code power (RSCP) is required for 3G and Rx level and Rx quality are required for 2G.

The required parameters are measured once each time the vehicle drives through the tile. These measurements are updated continuously every time the vehicle drives through the tiles. In one version, the measured values are not saved directly, but the mean value and the variance of the measurements are saved. Each time the vehicle drives through the tile, the stored mean and variance are updated with the new measurements. The mean and the variance of the signal strength parameters are then stored for each of the available interfaces for each location or tile. In this example, three sets of values are required for each location (tile) because there are two 4G interfaces and one WLAN interface.

For example, 4G, RSRP, RSRQ, and SINR can be directed to a data rate estimation model, which is a predefined model that is responsible for translating these parameters into available data rate values.

When a tile is visited for the first time and no measurements are included for that tile, the data can be easily saved for that tile as explained above. However, if a measurement for the tile already exists, either previously measured from the vehicle or already included in the initial map, then new measurements are merged with the previous measurements, e.g. a moving average algorithm, e.g. an exponential moving algorithm Average value algorithm (EMA: Exponential Moving Average) is used.

As mentioned above, only the mean and variance of the measurements are stored in execution and these are the values processed by the exponential moving average algorithm.

wobei y'(t) die neue Abschätzung ist, y(t) der gegenwärtig gemessene Wert ist, y'(t-1) die vorherige Aschätzung ist, α und β Gewichtungen sind, um die Gewichtung der gegenwärtigen und vergangenen Abschätzungen zu gewichten. Die Verwendung eines solchen gleitenden Durchschnittswerts erfordert, lediglich einen Wert für jede Abschätzung und nicht die vollständige Historie zu speichern. Weiterhin haben gegenwärtige Messungen eine höhere Gewichtung als vergangene Messungen und die Werte passen sich automatisch an neue Bedingungen an.An exponential moving average algorithm is a type of moving average algorithm according to which the current measurements are more important than historical measurements, ie: $$\text{y}\text{'}\left(\text{t}\right)=\mathrm{\alpha }\text{y}\left(\text{t}\right)*\mathrm{\beta }\text{y}\text{'}\left(\text{t-}1\right),$$

where y '(t) is the new estimate, y (t) is the currently measured value, y' (t-1) is the previous estimate, α and β are weights to weight the weight of the current and past estimates. Using such a moving average requires only storing one value for each estimate and not the full history. Furthermore, current measurements have a higher weighting than previous measurements and the values automatically adapt to new conditions.

The system can also measure the signal strength for the inactive interfaces while moving to obtain one or more reliable coverage cards. After a few measurements, the data stored within the coverage map becomes more robust due to the moving average concept. A relationship between the stored signal parameter values can then be created under the various interfaces within a tile, which means that after only measuring the values for one interface, this can be sufficient for the other interfaces so that they can be updated accordingly based on the previously created model between the different interfaces for this specific tile.

Initially, the map is divided into tiles with a size of approximately 50 mx 50 m, tiles in the area of 50 mx 100 m show similar properties, as tests have shown, so that the size in this area can be adapted, for example to the NDS Format to match.

A simple approach can be to set all values to 0 and fill them when accessing the tile with metrics.

A geographic area should be used to determine the signal strength at a given location before a vehicle hits a tile. The expected signal strength can be calculated by using the position of the base stations, environmental information such as buildings, city, rural area and related models for further signal propagation such as free space, Rayleigh fading, a distance to a road and a transmission power . These initial values are updated when a vehicle hits a tile and measures values that are more accurate.

The use of a database provided by telecommunications providers or openly available data can also be combined with the previous approach to estimate free spaces for which no information is available in the database.

The initial values are updated when a vehicle hits a tile and measures more values that are accurate.

1. 1. Wenn die Messwerte ähnlich sind, d. h. wenn der Mittelwert und die Varianz ähnlich sind, können Kacheln zu einer Kachel zusammengefasst werden.
   1. a) angenommen eine normale Verteilung von gemessenen Werten,
   2. b) eine Varianz ist kleiner als 0,5 für benachbarte Kacheln,
   3. c) der Mittelwert einer benachbarten Kachel im Bereich plus/minus Varianz des Mittelwerts der gegenwärtigen Kacheln, Kacheln werden kombiniert und lediglich ein Mittelwert und eine Varianz werden gespeichert für die zusammengefassten Kacheln. Der neue Mittelwert und die Varianz sind der geometrische Mittelwert der zusammengefassten Werte.
   4. d) Wenn die Varianz der Kacheln groß wird, wird die Kachel in mehrere Kacheln unterteilt, bis das kleinste Level erreicht ist. Wenn bspw. die Varianz über 0,75 gelangt, wird die Kachel geteilt.
   5. e) Daher ist ein Zusammenfassen und ein Teilen ein iterativer Prozess basierend auf der Varianz. Die Schwellwerte der Varianz können angepasst werden.
   6. f) Die Zusammenfassung kann bei allen benachbarten Kacheln oder nur bei Kacheln in longitudinaler oder latitudinaler Richtung angepasst werden.
2. 2. Ein Zusammenfassen basierend auf physikalischen Modellen:
   • In ländlichen oder städtischen Bereichen existieren physikalische Modelle für eine Signalausbreitung. Werden die Modelle verwendet, können die erwarteten und gemessenen Werte für eine Kachel verglichen werden, wenn die Werte gleich sind, keine Werte für die Kachel müssen gespeichert werden, nur die Informationen, die für diese des physikalischen Modells angewendet werden, müssen gespeichert werden. Wenn das Modell auf benachbarte Kacheln angewendet wird, können diese Kacheln wiederum zusammengefasst werden.

Tiles can be grouped together to reduce memory usage if they are similar. A tile size of 50 mx 50 m is required for locations where conditions change quickly, e.g. in urban areas. In rural areas with fewer buildings, conditions are stable over longer distances. Therefore, these places can be summarized. There are two ways to summarize them:

1. 1. If the measured values are similar, ie if the mean and the variance are similar, tiles can be combined to form a tile.
   1. a) assuming a normal distribution of measured values,
   2. b) a variance is less than 0.5 for neighboring tiles,
   3. c) the average of a neighboring tile in the range plus / minus variance of the average of the current tiles, tiles are combined and only an average and a variance are stored for the combined tiles. The new mean and the variance are the geometric mean of the combined values.
   4. d) If the variance of the tiles becomes large, the tile is divided into several tiles until the smallest level is reached. If, for example, the variance exceeds 0.75, the tile is divided.
   5. e) Therefore, summarizing and sharing is an iterative process based on the variance. The threshold values of the variance can be adjusted.
   6. f) The summary can be adjusted for all neighboring tiles or only for tiles in the longitudinal or latitudinal direction.
2. 2. A summary based on physical models:
   • In rural or urban areas, physical models for signal propagation exist. If the models are used, the expected and measured values for a tile can be compared if the values are the same, no values for the tile need to be saved, only the information that is used for them of the physical model has to be saved. If the model is applied to neighboring tiles, these tiles can be combined again.

In order to adapt a measurement of parameters to a single tile, the measurement should be finished while crossing the tile. Ideally, a measurement starts at the beginning of a tile and ends before leaving this tile. Measurements should also be carried out quickly.

• Eine Information der Kachel wird gelöscht, wenn diese nicht kontinuierlich aktualisiert wird, so dass die Speicherkapazität freigegeben wird und alte Daten entfernt werden.

Some additional features can be added to the system, which increases its capabilities, such as:

• Information on the tile is deleted if it is not continuously updated, so that the storage capacity is released and old data are removed.

To further optimize the use of the memory, only tiles with meaningful data are used. Only tiles that cover areas that can be reached by the vehicle or the mobile device are included, so that tiles that cover, for example, the sea or a desert will not be included, since these places are not mobile or Provide WiFi signal.

Tiles with similar signal characteristics, indicated by the same mean and less variance, can be grouped together to reduce memory requirements. An increase to a higher degree of enlargement means that the number of tiles is reduced by two bits. More details are given below.

The system presented can also be made available to smartphone users, including all positions, for example also positions in buildings.

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• US 2006021142 A [0004]
• US 2015020140 A [0005]

Claims (12)

Method for creating a coverage map in a mobile device, the coverage map being divided into tiles (12, 14, 22) and passive data for at least some of the tiles (12, 14, 22) being measured for at least one signal characteristic for at least one service, and with the aid of a model, the passive data is converted into information relating to a data rate of the respective service, this information being connected to the assigned card. Procedure according to Claim 1 , in which the signal characteristic relates to a signal strength. Procedure according to Claim 1 , in which the signal characteristic relates to a bandwidth. Procedure according to one of the Claims 1 to 3rd , in which the information relating to the data rate relates to a statistical distribution of the data rate. Procedure according to Claim 4 , in which a mean value and a variance are determined as information. Procedure according to one of the Claims 1 to 5 , in which initial information on the at least one data rate is used. Procedure according to Claim 6 , in which the initial information is linked to information based on measured signal strengths. Procedure according to Claim 7 , which uses an exponential average algorithm when linking. Procedure according to one of the Claims 1 to 8th , in which tiles (12, 14, 22) are combined. Procedure according to one of the Claims 1 to 9 , which also takes environmental conditions into account. Arrangement for creating a cover map, which is used to carry out a method according to one of the Claims 1 to 10th is set up. Order after Claim 11 which comprises a mobile signal strength detector, a model which converts the acquired signal strength values into information on a data rate, and a position detector.

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