Device, method and computer program for frequency band selection

Abstract

Device (2, 3) for influencing the selection of a frequency band for wireless communication with a mobile station (1), comprising - Transmitting circuit (10) configured to transmit a beacon signal with a first transmit power in the frequency band; - Detection circuit (11) designed to detect a connection request from a mobile station in the frequency band; - Control circuit (12) configured to cause the beacon signal to be transmitted with a second transmission power different from the first transmission power when a connection request is made, if the mobile station (1) is unknown to the device (2, 3), and - that the control circuit (10) is further developed to maintain the second transmission power for a predetermined time and then initiate the first transmission power again.

Description

[0001] Exemplary embodiments of the present invention generally relate to the control of a frequency band selection and, in particular, the control of the frequency band selection for existing devices, provided they support at least two frequency bands. This control system can also be installed in motor vehicles.

[0002] Wireless local area networks (WLANs) can also be deployed inside vehicles. Such networks can be established between mobile stations and base stations, which can be permanently installed in vehicles. Base stations are also referred to as devices in this context. Common frequency bands for WLANs are 2.4 GHz and 5 GHz. For efficient operation of WLANs, it is advantageous to assign specific frequency bands to participating stations. This allows for efficient use of the available radio spectrum and bandwidth. For ease of use, it is beneficial to use the same Service Set Identification (SSID) in both frequency bands, so that they appear to the user as a single network.The frequency band selection is assigned to the mobile station in the WLAN standard. Therefore, the base station has only limited influence on this selection.

[0003] Known base station control methods for prioritizing a frequency band alter the base station's behavior towards mobile stations. For example, association confirmation messages from the base station to the mobile station can be delayed or even not sent at all by the vehicle-mounted base station if the mobile station attempts to establish association on the non-preferred frequency band. On the preferred frequency band, however, the corresponding confirmation can be sent immediately by the base station. However, such methods are unreliable and dependent on the specific circumstances, the environment, and the device implementations. Furthermore, the performance of the respective band is reduced, at least temporarily.

[0004] Arnold, A.; Decision aid; c't Magazine for Computer Technology, Issue 24, pp.196-198, 2012, teaches a client control for better load balancing in WLAN using situation-dependent probe response commands from the access points.

[0005] US 2007 / 182643 A1 teaches an antenna system comprising a first, second, and third antenna arranged on a printed circuit board (PCB). These include an arc-shaped element with a concave side and a convex side, and a conducting element extending substantially radially from the center of the concave side.

[0006] LANCOM Systems: Techpaper WLAN Band Steering. 2012 - This company publication explains the advantages of band steering, such as increased transmission rates for 5GHz clients, as well as the principles of operation and configuration options for LANCOM access points.

[0007] US 2012 / 224483 A1 teaches the provision of good quality of service (QoS), corresponding service level agreements (SLAs), and a reliable connection of wireless devices with good signal strength, a good signal-to-noise ratio (SNIR), and sufficient usable bandwidth. For this to happen, the devices must ensure bandwidth-efficient reception of data packets over the air and be able to handle bottlenecks in the air interface.

[0008] US 2012 / 275320 A1 teaches a signal-strength-dependent band control. It demonstrates a system and a method that receives a current request from a client and responds taking into account the signal strength of the previous request.

[0009] US 2013 / 155949 A1 teaches a method and a device for compensating for band performance. The device is designed for communication with various wireless devices and includes two antennas for different frequency bands. The signal strength in the first frequency band is greater than the signal strength in the second frequency band.

[0010] US 2012 / 300759 A1 teaches support for an operational band in a wireless local area network (WLAN). A relative priority of a frequency band is provided to guide a WLAN device in choosing a preferred frequency band.

[0011] US 2005 / 250528 A1 teaches a system for a wireless network based on transmit power control and a method for controlling the transmit power. Newly emerging stations can easily associate themselves with a base station and communicate via the base station.

[0012] Therefore, it would be desirable to offer alternative selection options that, without changing the WLAN standard, influence the selection of existing mobile stations with the possibility of using multiple frequency bands.

[0013] This is achieved by a device, a method, and a computer program, each with the features of the independent patent claims. Advantageous embodiments and further developments are the subject of the dependent claims.

[0014] The core idea of ​​the invention is to influence the frequency band selection of mobile stations by making the non-preferred frequency band "invisible". Thus, the mobile station automatically switches to other, visible frequency bands, provided they are within its range.

[0015] According to a first aspect, exemplary embodiments provide a device for influencing the selection of a frequency band for wireless communication with a mobile station. The device comprises a transmitting circuit configured to send a beacon signal with a first transmit power in the frequency band. Furthermore, the device comprises a detection circuit configured to detect a connection request from a mobile station in the frequency band. Finally, the device comprises a control circuit configured to initiate the transmission of the beacon signal with a second transmit power different from the first upon a connection request if the mobile station is unknown to the device. Thus, it is advantageously possible to influence the frequency band selection for all mobile stations that support at least two frequency bands.

[0016] Optionally, the control circuit can be further developed to set the second transmit power lower than the first. This advantageously supports the selection effect while simultaneously conserving radio resources in the non-preferred frequency band.

[0017] In some embodiments, the control circuit can be further developed to maintain the second transmission power for a predetermined time and then resume the first transmission power. Advantageously, this only temporarily reduces the association capability of the non-preferred frequency band.

[0018] In some embodiments, the control circuit can be further developed to maintain the initial transmit power when a connection request is made by a mobile station known to the device in the frequency band. This advantageously supports association with the non-preferred frequency band if the mobile station's association attempt with the preferred frequency band fails.

[0019] Optionally, the control circuit can be further developed to store a unique terminal identifier in the device when an unknown mobile station requests a connection in the frequency band. This allows for the advantageous detection of repeated association attempts by the mobile station in the frequency band.

[0020] In some embodiments, the control circuit can be further developed to check, with each connection request in the frequency band, whether the individual terminal identifier is stored. This can advantageously facilitate further association attempts of the mobile station in this frequency band.

[0021] In some embodiments, the control circuitry can be further developed to delete the individual terminal identifier after a connection is terminated or after a predetermined time has elapsed. This advantageously allows for the re-influencing of the mobile station's frequency band selection during a subsequent association attempt.

[0022] Optionally, the transmission circuitry can be further developed to accommodate the 2.4 GHz frequency band and another frequency band at 5 GHz, and / or to be configured as a Wireless Local Area Network (WLAN) frequency band. This advantageously allows a large number of standardized mobile stations to associate with the base station.

[0023] In some embodiments, the device may further include a transmitting circuit configured to send a beacon signal in another frequency band with a transmit power specific to that additional frequency band. The device may also include a detection circuit configured to detect a connection request from a mobile station in that additional frequency band. Furthermore, the device may include a control circuit configured to acknowledge the mobile station's connection request. Advantageously, this enables the mobile station to associate itself with the preferred frequency band.

[0024] Optionally, a motor vehicle may be equipped with a device according to one of the aforementioned embodiments, wherein the device is arranged in such a way that the entire interior of the motor vehicle is available for spatial positioning of the mobile station for communication with the device.

[0025] In some embodiments, a method is used to influence the selection of a frequency band for wireless communication between a device and a mobile station. This method includes transmitting a beacon signal with a first transmission power in the frequency band. Furthermore, the method includes detecting a connection request from a mobile station in the frequency band and transmitting the beacon signal with a second transmission power different from the first if the mobile station is unknown to the device. Thus, it is advantageously possible to influence the frequency band selection for all mobile stations that support at least two frequency bands.

[0026] In some embodiments, a method can be used in which a connection request from an unknown mobile station in the frequency band is rejected. Advantageously, an initial connection request in the non-preferred frequency band can thus be rejected.

[0027] Optionally, a method can be used in which a beacon signal is transmitted in another frequency band, and the mobile station's connection request is confirmed in that additional frequency band. This allows the preferred frequency band to be used, which is advantageous.

[0028] In some embodiments, a method can be used in which the second transmission power is maintained in the frequency band for a predetermined time and then transmission resumes at the first power. This advantageously limits the reduced availability for establishing a connection in the frequency band to a specific time period.

[0029] In some embodiments, a method can be used in which, when an unknown mobile station makes a connection request in the frequency band, a unique terminal identifier is stored to announce the mobile station. This advantageously allows detection of repeated connection attempts by the mobile station in that frequency band.

[0030] Optionally, a procedure can be used whereby a known mobile station confirms the connection request when it is made in the same frequency band. This advantageously enables a connection between the mobile station and the base station even if the use of the preferred frequency band has failed.

[0031] In some embodiments, a computer program can be used to perform at least one step of the above-mentioned method, wherein the computer program runs on a programmable hardware component.

[0032] In some embodiments of a further exemplary embodiment, a device can control frequency band selection for wireless communication with a mobile station in a Wireless Local Area Network (WLAN), in which at least a first and a second frequency band are selectable, the first and second frequency bands each comprising a plurality of transmission channels. The device includes a transmit circuit for sending at least one command to the mobile station, instructing the mobile station to switch from the first to the second frequency band or vice versa. Advantageously, this enables reliable switching between compatible devices.

[0033] Optionally, the device can include a provisioning circuit to provide the results of authentication and / or association between the mobile station and the device, and / or a dynamic host configuration protocol (DHCP) procedure, determined before switching from the first to the second frequency band or vice versa, which continue to be used after the switch. This advantageously conserves radio resources.

[0034] In some embodiments, the device can include a control circuit for establishing a Media Access Control (MAC) between the mobile station and the device after switching from the first to the second frequency band or vice versa. Advantageously, reference can be made to the existing IEEE 802.11 standard.

[0035] In some embodiments, the device may include a switching circuit to maintain the agreed association between the device and the mobile station when switching from the first to the second frequency band or vice versa is not possible. This advantageously prevents disassociation.

[0036] In further embodiments, the mobile station corresponding to the device can be equipped according to the features of the device. Furthermore, corresponding processes can take place between the mobile station and the device.

[0037] Optionally, embodiments of the first and the further embodiment can also be combined. For example, embodiments of frequency band selection via beacon lowering can be followed by embodiments of frequency band selection via command later in the connection. Advantageously, this allows changing conditions of an air interface between the stations to be taken into account over time without requiring an interruption of the connection.

[0038] Some exemplary embodiments of the present invention are explained in more detail below with reference to the accompanying figures. These show: Fig. Figure 1 shows a schematic diagram of a WLAN setup with mobile station and base station Fig. Figure 2 shows a possible arrangement of a WLAN base station in a car Fig. Figure 3 shows a schematic diagram of a WLAN base station Fig. Figure 4 shows a first example of a signaling sequence. Fig. Figure 5 shows a second example of a signaling sequence.

[0039] Several embodiments are now described in more detail with reference to the accompanying drawings, in which some of these embodiments are illustrated. For the sake of clarity, the thickness dimensions of lines, layers, and / or regions may be exaggerated in the figures.

[0040] In the following description of the accompanying figures, which merely show some exemplary embodiments, the same reference numerals can denote identical or comparable components. Furthermore, collective reference numerals can be used for components and objects that appear multiple times in an embodiment or in a drawing, but are described jointly with respect to one or more features. Components or objects described with the same or collective reference numerals can be identical with respect to one, several, or all features, such as their dimensions, but may also differ, unless the description explicitly or implicitly indicates otherwise.

[0041] Although embodiments can be modified and altered in various ways, they are shown in the figures as examples and are described in detail herein. It should be clarified, however, that the intention is not to limit embodiments to the forms disclosed, but rather that they are intended to cover all functional and / or structural modifications, equivalents, and alternatives within the scope of the invention. The same reference numerals throughout the figure description denote identical or similar elements.

[0042] The terminology used herein serves only to describe specific embodiments and is not intended to limit the embodiments. As used herein, the singular forms "a," "an," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise. Furthermore, it should be clarified that expressions such as "includes," "containing," "exhibits," and / or "indicating," as used herein, indicate the presence of the aforementioned features, integers, steps, processes, elements, and / or components, but do not preclude the presence or addition of one or more features, integers, steps, processes, elements, components, and / or groups thereof.

[0043] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning that an average person skilled in the field to which the examples of implementation belong would ascribe to them. Furthermore, it should be clarified that expressions, e.g., those defined in commonly used dictionaries, are to be interpreted as having the meaning consistent with their meaning in the context of the relevant technology, and not in an idealized or overly formal sense, unless expressly defined herein.

[0044] The Fig. Figure 1 shows a schematic diagram of a WLAN setup with a mobile station and a base station. Both devices are connected via an wireless interface according to the aforementioned WLAN standard. This standard is also known as IEEE 802.11, which has various versions with different performance characteristics. Devices conforming to one of these versions can communicate with all other devices of the same version without requiring any separate device configuration. Furthermore, the standard is characterized by direct communication between the two devices, thus avoiding the need for switching equipment or similar intermediaries. Mobile station 1 can therefore exchange data directly with base station 2. Base station 2 transmits a recognition signal, the so-called beacon, which identifies it and communicates its characteristics.If a mobile station 1 detects a suitable beacon, it can establish a connection to the base station 2 using appropriate protocol elements.

[0045] The Fig. Figure 2 shows a possible arrangement of a WLAN base station 3 in a passenger car 4. Base stations of the WLAN standard are usually installed in a fixed location. This installation depends on the requirements and can be for both private and public transport. In this invention, the base station is arranged in a motor vehicle, which can include all common types such as cars, trucks, etc. This arrangement can be implemented as a permanent installation or a temporary installation and also includes the possibility of factory installation by the vehicle manufacturer. For example, the base station can be installed in the rearview mirror, in the console, or connected to an interior lighting system.The base station is positioned in such a way that essentially the entire interior of the vehicle is available for the placement of the mobile station, ensuring good connection quality to the base station. Optionally, a connection near the vehicle can also be included.

[0046] The Fig. Figure 3 shows a schematic diagram of a WLAN base station 2. The base station shown includes the means for WLAN standard-compliant communication over two frequency bands: the 2.4 GHz band and the 5 GHz band. The latter was added in a later version of the standard. Consequently, some mobile stations can only communicate in the 2.4 GHz band. Newer mobile stations can communicate in both bands. The 5 GHz band has a significantly increased channel bandwidth and a higher-quality modulation technique. Therefore, the channel capacity in this frequency band is considerably higher compared to the 2.4 GHz band. For this reason, it is advantageous to route data traffic to the 5 GHz band whenever possible. This also helps to keep the 2.4 GHz band free for older mobile stations.

[0047] Base station 2 can communicate on both frequency bands. It has a symmetrical design for both frequency bands. The components for the 2.4 GHz band include a transmit circuit 10, a detection circuit 11, and a control circuit 12. The transmit circuit 10 is connected to a transmit / receive antenna 15 and is designed to transmit a power of up to 20 dBm (100 mW) EIRP (equivalent isotropically radiated power). Since a high degree of antenna directivity, which can also be understood as the orientation of the antenna's effective direction, is to be expected in the vehicle, the power fed into the antenna is typically around 14 dBm (25 mW).As previously explained, this beacon signal serves mobile stations 1 to detect the presence of a base station 2 and simultaneously includes various pieces of information from base station 2, such as the network name (Service Set Identifier, SSID), a list of supported data rates, and / or the type of encryption. The initial transmission power is set so that mobile stations 1 that detect the signal can exchange data with base station 2 with a presumably sufficient quality. The transmission circuit is also designed to transmit a beacon signal at reduced power. A significant reduction is possible, for example, by 20 dB. However, smaller or larger reductions can also be set, depending, among other things, on the installation location in the vehicle (which can also be understood as the intended location for a base station inside the vehicle) or other environmental parameters.A beacon with this reduced transmission power can no longer be detected by many mobile stations. Accordingly, mobile station 1 will not attempt to establish a connection or association on this frequency band, but will instead turn to other frequency bands if possible. The transmitting circuit 10 is connected to the detection circuit 11. This detects a connection request from mobile station 1 to base station 2 in the assigned 2.4 GHz frequency band. The connection circuit 10 is also connected to the control circuit 12. Among other things, this circuit controls the transmission power of the beacon signal. To do this, it determines whether the mobile station 1 currently requesting an association is still unknown to base station 2. If so, it instructs the transmitting circuit 10 to significantly reduce the transmission power of the beacon signal.However, if the requesting mobile station 1 is already known to the base station 2, the control circuit 10 refrains from reducing the transmission power of the beacon signal.

[0048] For the 5 GHz band, corresponding components with essentially similar functions are provided in base station 2: transmit circuit 20, detection circuit 21, and control circuit 22. However, the 5 GHz band circuits are not equipped with a power reduction function for the beacon signal, as the 5 GHz frequency band is the preferred frequency band. Accordingly, transmit circuit 20 does not exhibit a reduction function for the transmit power of the beacon signal, and control circuit 22 does not have a corresponding transmit power control. Transmit circuit 20 can be connected to a separate antenna 25. Alternatively, both transmit circuits 10 and 20 can be connected to both antennas 15 and 25.

[0049] The Fig. Figure 4 shows a first example of a signaling sequence between a mobile station 1 and a base station 2 in a WLAN system 100. The base station 2 includes a 2.4 GHz circuit block 101, which, for example, contains circuits 10-12. Fig. 3. Furthermore, base station 2 includes a 5GHz circuit block 102, which, for example, includes circuits 20-22 from the Fig. It can comprise 3. Circuit blocks 101 and 102 are shown as examples, each connected to separate antennas.

[0050] The circuit blocks for 2.4 GHz (101) and 5 GHz (102) each transmit a beacon signal at the power specified in the standard. At least the 2.4 GHz beacon signal is detected by mobile station 1, which then attempts to establish a connection with base station 2. Mobile station 1 subsequently sends an association request (110) to base station 2 in the 2.4 GHz band. Circuit block 101 then checks whether an identifier for this mobile station is already stored in base station 2 (not shown). This identifier can be a Media Access Control (MAC) address in the WLAN standard. If the identifier is not stored, the association request from mobile station 1 is rejected, and a corresponding message, which might be formatted as "Association Response: NOK 120", is sent back. The identifier for mobile station 1 is then stored in base station 2.The transmission power of the beacon signal for 2.4 GHz is further reduced. Mobile station 1 is additionally equipped with the 5 GHz frequency band and receives the corresponding beacon signal on this frequency. Mobile station 1 then sends an association request 110 in the 5 GHz band to base station 2. Circuit block 102 accepts the association request and initiates the transmission of a corresponding message 130, the Association Response: OK. Thus, mobile station 1 is successfully associated with base station 2, and user data can be exchanged.

[0051] The Fig. 5 shows the arrangement of Fig. 4 for another embodiment. The upper operation 110 (Association Request) and the negative response 120 (Association Response: NOK) correspond to the operations in the Fig.4. Description. The (not shown) identification process also takes place in base station 2. However, in this embodiment, mobile station 1 is unable to operate on the 5 GHz band. Alternatively, mobile station 1 may also be unable to receive the 5 GHz beacon. The same applies to the 2.4 GHz beacon, whose transmit power is reduced. Accordingly, no connection is possible at this time. After a predetermined time, typically 3 seconds, circuit block 101 reduces the transmit power of the 2.4 GHz beacon signal back to its nominal power in process 105. The time after which the power is reduced can also be shorter if the scan times of the mobile stations decrease due to technological improvements. Mobile station 1 then recognizes the 2.4 GHz beacon and attempts to re-associate with base station 2.In this case, circuit block 101 already knows the identifier of mobile station 1 and now accepts the association request from mobile station 1. Accordingly, base station 1 sends back an Association Response: OK 140. Data exchange between mobile station 1 and base station 2 can now take place in the 2.4 GHz band.

[0052] Once the connection is established, or after a predetermined time has elapsed if the connection attempt fails, the identifier of mobile station 1 is deleted from base station 2. This restores the input conditions for subsequent connection attempts.

[0053] In further embodiments, the beacon signal can be reduced to a transmission power inaudible to the mobile station for a predetermined period or, alternatively, switched off completely. The invention can be summarized as follows. Studies with various mobile stations have shown that rudimentary band control can be achieved by adjusting the signal strength in the 2.4 GHz and 5 GHz bands. If the 5 GHz band uses a much higher power than its 2.4 GHz counterpart, the mobile stations connect significantly more often in the 5 GHz band than in the 2.4 GHz band. Laboratory tests with a typical base station have shown that the difference in transmission power should be at least 14 dBm. To avoid disrupting normal operation, only the beacons and probe response frames have their transmission power reduced.

[0054] Wi-Fi coverage in the vehicle interior should be provided via both the 5 GHz and 2.4 GHz bands. Since the capacity in the 5 GHz band is significantly higher (due to channel bandwidth and superior modulation technology), it is desirable for end devices to preferentially connect to the 5 GHz Wi-Fi network – if available on the device. A reduction in the power output of the 2.4 GHz beacons is proposed to simulate better network quality for the 5 GHz network.

[0055] In another embodiment, frequency band change commands can be used to initiate a frequency band change. These frequency band change commands can, for example, be based on the standardized methods of the WLAN standard IEEE 802.11-2012 for channel switching, where an access point, also referred to as a base station in this description, mandates a channel change for its clients, which may be implemented in mobile stations. This is necessary for Dynamic Frequency Selection (DFS), where clearing a channel becomes necessary, for example, if radar interference is detected on the channel. Such channel change commands can be implemented within the frequency bands (5 GHz and / or 2.4 GHz).

[0056] A frequency band change command can be used to switch frequency bands. Unlike a channel change command, simply sending the corresponding frequency band change command from the base station to the mobile station is not sufficient for a frequency band change. Additionally, it should be noted that the switch must be made from one media access control MAC address (e.g., for 2.4 GHz) to another MAC address (e.g., for 5 GHz / GO). Furthermore, the frequency band change should be seamless. Such a seamless transition avoids, for example, the need for new authentication, a connection interruption, and / or a dynamic host configuration procedure (DHCP) in the new frequency band.In the event that the mobile station does not support the new frequency band (for example, the 5GHz frequency band), a band change procedure could ensure that the mobile station's connection is not completely disconnected from the network, but that the connection can remain in the previous frequency band (for example, the 2.4GHz frequency band).

[0057] The features disclosed in the foregoing description, the following claims and the accompanying figures can be important and implemented individually or in any combination for the realization of an embodiment in its various configurations.

[0058] Although some aspects have been described in connection with a device, it is understood that these aspects also constitute a description of the corresponding process, so that a block or component of a device can also be understood as a corresponding process step or as a feature of a process step. Similarly, aspects described in connection with or as a process step also constitute a description of a corresponding block, detail, or feature of a corresponding device.

[0059] Depending on specific implementation requirements, embodiments of the invention can be implemented in hardware or in software. The implementation can be carried out using a digital storage medium, for example a floppy disk, DVD, Blu-ray disc, CD, ROM, PROM, EPROM, EEPROM or FLASH memory, hard disk or other magnetic or optical storage medium, on which electronically readable control signals are stored that can interact with, or interact with, a programmable hardware component in such a way that the respective method is carried out.

[0060] A programmable hardware component can be a processor, a computer processor (CPU = Central Processing Unit), a graphics processor (GPU = Graphics Processing Unit), a computer, a computer system, an application-specific integrated circuit (ASIC = Application-Specific Integrated Circuit), an integrated circuit (IC = Integrated Circuit), a system-on-a-chip (SOC = System on Chip), a programmable logic element, or a field-programmable gate array with a microprocessor (FPGA = Field Programmable Gate Array).

[0061] In general, embodiments of the present invention can be implemented as a program, firmware, computer program, or computer program product with program code or as data, wherein the program code or data is / are effective in carrying out one of the methods when the program runs on a processor or a programmable hardware component. The program code or data can, for example, also be stored on a machine-readable medium or data carrier. The program code or data can be in the form of, among other things, source code, machine code, bytecode, or other intermediate code.

[0062] Another embodiment is a data stream, a signal sequence, or a sequence of signals that represents the program for carrying out one of the methods described herein. The data stream, signal sequence, or sequence of signals can be configured, for example, to be transferred via a data communication link, such as the Internet or another network. Other embodiments include signal sequences representing data that are suitable for transmission via a network or a data communication link, where the data represents the program.

[0063] The embodiments described above merely illustrate the principles of the present invention. It is understood that modifications and variations of the arrangements and details described herein will be obvious to other people skilled in the art. Therefore, it is intended that the invention be limited only by the scope of protection set forth in the following claims and not by the specific details presented herein by way of description and explanation of the embodiments.

Claims

[1] Device (2, 3) for influencing the selection of a frequency band for wireless communication with a mobile station (1), comprising - Transmitting circuit (10) configured to transmit a beacon signal with a first transmit power in the frequency band; - Detection circuit (11) designed to detect a connection request from a mobile station in the frequency band; - Control circuit (12) configured to cause the beacon signal to be transmitted with a second transmission power different from the first transmission power when a connection request is made, if the mobile station (1) is unknown to the device (2, 3), and - that the control circuit (10) is further developed to maintain the second transmission power for a predetermined time and then initiate the first transmission power again. [2] Device (2, 3) according to claim 1, characterized by, that the control circuit (10) is further developed to set the second transmit power lower than the first transmit power. [3] Device (2, 3) according to one of the preceding claims, characterized by , that the control circuit (12) is further designed to maintain the first transmit power when a connection request is made by a mobile station (1) known to the device (2, 3) in the frequency band and / or that the control circuit (12) is further designed to store an individual terminal identifier in the device when a connection request is made by an unknown mobile station in the frequency band. [4] Device (2, 3) according to claim 1, characterized by , that the control circuit (12) is further developed to check, on every connection request in the frequency band, whether the individual terminal identifier is stored. [5] Device (2, 3) according to claim 4, characterized by, that the control circuit (12) is further designed to delete the individual terminal identifier after a connection is terminated or after a further specified time has elapsed. [6] Device (2, 3) according to any one of claims 1-5, characterized by , that the transmitting circuit (10) is further developed to arrange the frequency band at 2.4GHz and another frequency band at 5GHz and / or to design it as a wireless local area network - WLAN - frequency band. [7] Device (2, 3) according to any one of claims 1-6, characterized by , that the device (2, 3) further comprises: - Transmitting circuit (20) configured to transmit a beacon signal in the wider frequency band with a transmit power specific to the wider frequency band; - Detection circuit (21) configured to detect the connection request of a mobile station in the wider frequency band; and - Control circuit (22) which is configured to acknowledge the connection request of the mobile station. [8] Motor vehicle (4) with a device (3) according to one of claims 1-4, wherein the device (2,3) is arranged such that the entire interior of the motor vehicle (4) is available for spatial positioning of the mobile station (1) for communication with the device (2, 3). [9] Method for influencing the selection of a frequency band for wireless communication between a device and a mobile station, comprising: - Emitting a beacon signal with an initial transmission power in the frequency band; - Detect a connection request (110) from a mobile station in the frequency band; and - Transmission of the beacon signal with a second transmission power different from the first transmission power if the mobile station of the device is unknown, and - to maintain the second transmission power for a specified time and then to resume the first transmission power. [10] Method according to claim 9, characterized by , that the connection request (110) from the unknown mobile station in the frequency band is rejected. [11] Method according to claim 9 or 10, characterized by , that a beacon signal is sent in another frequency band and the connection request (110) of the mobile station is confirmed in that other frequency band. [12] Method according to any one of claims 9 to 11, characterized by , that in the frequency band the second transmission power is maintained for a predetermined time and then transmission resumes with the first transmission power. [13] Method according to any one of claims 9 to 12, characterized by , that when an unknown mobile station makes a connection request (110) in the frequency band, an individual terminal identifier is stored to announce the mobile station. [14] Computer program for carrying out at least one step of the above-mentioned method according to claims 9-13, wherein the computer program runs on a programmable hardware component.

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