Communication device, system and method for communication between a communication device and at least two base stations

Abstract

Method for communication between a communication device and at least one first (10) and one second (20) base station, comprising the steps of: a) establishing a voice and / or data connection between the communication device and the first base station (10); b) determining / receiving position data (PosData) of the communication device (40), wherein the position data (PosData) includes street data (StrData); c) determining / receiving handover parameters based on the street data (StrData), wherein the handover parameters are a handover trigger time interval, namely at least a TTT value, and radio quality information, namely at least a HOM value; d) handing over a voice / data connection to the second base station (20) taking into account the determined / determined handover parameters;and storing a modified TTT value and a modified HOM value together with transfer qualities that specify the quality of the transfer from the first (10) to the second base station (20), wherein the modification of the TTT value and the HOM value includes an optimization, minimizing a data loss rate (Rout(&thgr;)) for a given number of ping-pong transfers (Rpp(&thgr;)).

Description

The invention relates to a communication device for communication with at least two base stations, a system for providing communication between a communication device and at least two base stations, and a corresponding method. In mobile telecommunications networks, such as GSM (Global System for Mobile Communications), UMTS (Universal Mobile Telecommunications System), or LTE (Long Term Evolution), it is necessary for mobile devices to be able to switch from one cell to another during a call or data connection without interrupting the connection. This process is called connection handover. The handover process can be evaluated using key performance indicators (KPIs). These can include data regarding radio link failure (RLF) or the frequency of handovers (HPR). HPR describes the frequency of consecutive handovers between two remote communication cells. The KPIs depend on several parameters that control the handover process. These include, for example, the time-to-trigger (TTT) value, which specifies the time interval that must elapse before a handover is actually executed. Another relevant parameter is the handover offset margin (HOM).This HOM value represents the difference between the signal strength measured at the end device of the currently serving cell tower and that of the future cell tower. A handover is only initiated if the signal strength of the current cell tower is weaker by at least this difference value over a predefined time interval (e.g., TTT value). The current state of the art regarding handover procedures is based on assigning handover parameters (TTT value and HOM value) globally or on a cell-specific basis. Accordingly, only cell-specific handover parameters are assigned to a cell, so that the aforementioned handover ping-pong effects or radio link failures, i.e., radio link errors, can still occur. From DE 10 2008 003 639 A1 a method for operating a communication system is known which is designed in such a way as not to establish unnecessary network connections to new networks if, for example, a motor vehicle would only stay briefly in the new network. In WO 2009 / 058 069 A1, a method for adjusting mobility parameters in a wireless communication network is described, wherein two speed estimates are carried out for a user device at a base station, and an adjustment of at least one mobility parameter is made based on a comparison of the first and second speed estimates. From WO 2005 / 027 556 A1, a method is known for deciding whether to transfer a communication link between a mobile device and a current network to an available network. This method involves determining connection parameters for each candidate network, which describe the communication link between the mobile device and each candidate network after the transfer. A target network is selected from the candidate networks based on a comparison of the connection parameters of each candidate network. The communication link is then transferred from the current network to the target network. WO 2001 / 191 08 A1 discloses a method that is carried out by a mobile telecommunications terminal located in a vehicle. A trajectory of the vehicle within a mobile network is determined in advance, and the coverage quality along the trajectory is determined based on the information available in the mobile telecommunications terminal regarding the geographical distribution of coverage quality. The object of the present invention is to improve handover. In particular, a communication device is to be provided which enables efficient and uninterrupted communication with at least two base stations, especially for the 3GPP LTE standard. Furthermore, a corresponding system and a corresponding method are to be specified. The problem is solved by a method for communication between a communication device and at least one first and at least one second base station. This method can be implemented with communication devices as described below. The first and second base stations preferably belong to a system as described below. The method comprises the following steps: a) establishing a voice and / or data connection between the communication device and the first base station; b) determining / receiving position data from the communication device, wherein the position data includes street data; c) determining / receiving transfer parameters based on the street data; d) transferring the voice and / or data connection to the second base station, taking into account the determined / transmitted transfer parameters. Optionally, in one step, the movement speed data and / or the movement direction data of the communication device are acquired / received, whereby this speed or direction data is taken into account when determining the transfer parameters. The transfer parameters in step c) are a trigger time interval for the transfer, namely a TTT value, and a radio quality indication, namely a HOM value, which are determined / received. Furthermore, the inventive method provides that a modified TTT value and a modified HOM value are stored together with transfer qualities that indicate the quality of the transfer from the first to the second base station. Some of the data required for communication between at least one communication device and at least two base stations (position data, street data, transfer parameters) can be stored decentrally or centrally. In one embodiment, the street data and transfer parameters are stored in the base stations. A system-wide storage location is also theoretically conceivable. Accordingly, the procedure may further include the following steps: f) transmission of the TTT value and / or the HOM value from a base station to a communication device and g) modification of the TTT value and / or the HOM value by the communication device. The TTT and HOM values ​​transmitted to a communication device can be modified, for example, based on the speed and / or direction of travel. The speed of travel refers to the road on which the communication device is located, and the average and / or maximum speed of the road can be taken into account when modifying the values. The direction of travel can be determined from the course of the road on which the communication device is located. The modified values ​​and the transfer qualities can be stored in a memory of the communication device, in a memory of one or more base stations, and / or in a higher-level memory. The procedure may further include the following steps: i) Quality measurement of the handover performed from the communication device to a second remote communication cell of a second base station using a modified TTT value and / or a modified HOM value; j) Comparison of the measured handover quality with stored handover qualities to optimize future handovers. If the measured handover quality is better than the stored handover qualities, or if the measured handover quality does not deviate from the achieved handover qualities, the modified TTT value and / or the modified HOM value that led to or is related to improved handover quality can be saved. This saving must be done in conjunction with the associated position data and / or road data and / or speed or direction data. Saving can be performed in the communication device and / or in the base station and / or at a higher level. In a further embodiment of the invention, a threshold value can be defined for a first input value, and a second input value can be modified as desired and compared with stored input qualities. For example, a threshold value is defined for a modified TTT value, and the HOM value is modified as desired and compared with stored input qualities. Consequently, one input value can be optimized or modified based on the condition of another input value. According to the invention, the modification of the TTT value and the HOM value is an optimization whereby Rout(θ) is minimized under the condition Rpp(θ) ≤ R. That is, the data loss rate Rout(θ) is minimized for a given number of ping-pong transfers Rpp(θ). R represents the desired ping-pong ratio. θ is a vector of m pairs of parameters {H, T} such that θ := (H1, ..., Hm, T1, ..., Tm). In the following, θ is defined as a set {H, T} such that θ is a concrete pair of parameters with respect to a street j, {Hj, Tj} for i = 1, ..., 2m, j = i mod m. Rout is the proportion of communication channel outages (Channel Outage Ratio). Rpp, on the other hand, is the proportion of handover ping-pong events (Handover Ping-pong Ratio). According to the invention, both ratios can be measured or collected by the base stations, wherein Nslots denotes the number of all counted timeslots after the occurrence of the A3 event, where this A3 event is the point in time when a base station of a neighboring long-distance communication cell provides a better signal with a difference strength of HOM than the base station currently being used. Nout is the number of timeslots that provide a signal that is too weak, such that the condition according to Γmin is not met within the fully counted timeslots. Nppund Nhobetreffen den Nummer den Zahlen Pingpong-Handovers oder das Nummer allen Handover oder Verbindungsüberlassung / Überlassungs. A transfer state A3 typically occurs when δ(t) > H, where δ(t) = pn(t) - ps(t). The probabilities with respect to Rout and Rpp are denoted by Pout and Ppp, where and and The handover period, on the other hand, is defined as [t0 + 1, t0 + T], where t0 = time slot when A3 occurs. A3, with respect to a ping-pong handover, will occur at time t1. This relates to the probability of a ping-pong handover, where can have an approximate value with respect to the probability of A3 occurring at time t1, where the handover is triggered after time T has elapsed. δ(t) relates to the RSRP difference (Reference Signal Received Power), where M(t+r) depends on the speed and direction of travel of the communication device or vehicle. C, on the other hand, is a constant that represents the variance of the RSRP difference and is based on a machine learning algorithm. Since the probability calculations according to formulas (4) and (6) cannot be explicitly calculated, the first two time points are used to derive the upper limits of and : where and where µ and σ are the mean and variance of δ(t0+r) and where µ' and σ' are the mean and variance of δ(t1+r). The optimization parameters are based on the parameters H and T, as well as the parameter M, which in turn incorporates the vehicle speed and direction of travel into the optimization values. Regarding M(t), see: and . Here, y(t) and φ(t) each refer to the signal strength at the communication device according to a wave propagation model at time t and a random signal at time t, respectively. For the calculation of y(t), the vehicle speed and direction of travel are required, whereby the maximum and average speeds and the direction of travel of the road on which the communication device is located can be selected. Furthermore, Δy(t) and Δp(t) are y(t) - y(t-1) and φ(t) - φ(t-1), respectively. The subscripts s and n denote the operating cell and the intended cell, respectively. Based on formulas (9) and (10), a heuristic approach can be chosen according to the invention to optimize the input parameters (T; H). Preferably, a road-specific optimization of the input parameters is carried out. This optimization can be performed according to the invention using the following pseudo-algorithm. The described devices can store transfer parameters that follow this optimization or perform this optimization to improve the handover. Likewise, the described methods can access and / or generate appropriately optimized values. The aforementioned problem is further solved by the communication device according to claim 5, which is designed for communication according to a method according to the invention. In particular, the task is solved by a communication device, preferably a (mobile) terminal device, which includes: - at least one position determination unit for determining position data of the communication device; - at least one radio transmitting / receiving unit for communication with at least one first and at least one second base station; - at least one transfer parameter determination unit for determining transfer parameters. According to the invention, the transfer parameter determination unit determines the position data for one of the base stations and / or the transfer parameters are identifiable in a memory based on the position data using the transfer parameter determination unit, wherein the position data are linked with street data. The transfer parameter determination unit can be configured such that it requests the required transfer parameters from a base station. The transfer parameters can be determined by or from the base station and transmitted to the communication device. Preferably, this communication device is mobile and / or part of a mobile system (e.g., a vehicle). The communication device can therefore be a mobile communication device, such as a mobile phone, or an on-board computer of a vehicle with appropriate interfaces. The positioning unit can receive data from an external device to determine its position or derive the corresponding position data independently. Such a positioning unit can be a module belonging to a global navigation satellite system, i.e., a GNSS module such as a GPS module, a GLONASS module, or a compass module according to the Chinese standard, which is either integrated into the communication device or provides corresponding data to the communication device. The position data can be, for example, geographical data or data identifying a specific street, a specific section of a street, a specific city, and / or a specific country. The radio transceiver unit is used for communication with at least two base stations. This communication with at least two geographically separated base stations is preferably uninterrupted, i.e., sequentially without any gaps in time. Therefore, a handover from a first base station to a second base station is necessary. The handover is performed based on handover parameters. At least one handover parameter determination unit is provided to determine these parameters. According to the invention, the transfer parameter determination unit transmits the position data to one of the base stations and / or identifies the transfer parameters in a memory based on the position data. The position data is in turn linked to street data, whereby the transfer parameters can be identified, for example, based on the depicted street data. In a further embodiment of the invention, the communication device can include a detection unit for acquiring the movement speed data and / or the movement direction data of the communication device. The movement speed data and / or movement direction data of the communication device are taken into account when determining the transfer parameters. Accordingly, the detection unit for acquiring the aforementioned data is signal-connected to the transfer parameter determination unit, so that the data acquired by the detection unit can be transmitted to the transfer parameter determination unit. If, for example, the communication device is part of a vehicle, the movement speed data is the speed of the vehicle. The movement direction data therefore corresponds to the direction of travel of the vehicle. Thus, when determining orDetermining the transfer parameters will for the first time include speed and direction data. According to the invention, the transfer parameter determination unit takes into account, for example, the following data when determining the transfer parameters: - data relating to a road course and / or - data relating to the radio wave propagation of at least one of the base stations and / or - data relating to a maximum speed associated with a road on which the communication device is located and / or - data relating to an average speed associated with a road on which the communication device is located. In one possible embodiment of the invention, data relating to the radio wave propagation of at least the currently operating base station and the intended future base station are taken into account when determining the transfer parameters. A memory can therefore store the average vehicle speeds and / or the maximum speeds applicable to a specific road or road segment, as determined for that road or road segment. If the communication device is located at a specific position on a particular road, this position is uniquely assigned to an average speed and / or maximum speed stored in the memory. Furthermore, data regarding the radio wave propagation of one or more base stations can be assigned to each position or position data record. Information regarding the road's course is therefore very useful, as it allows for the calculation of the likely position a communication device located on a road will reach. The handover parameters determined using the handover parameter determination unit are the trigger time interval, namely the TTT value, and radio quality information, namely the HOM value. The HOM value describes a difference in signal strength between the currently serving radio cell and the future radio cell. A handover is only initiated if the signal strength of the current radio cell is weaker by at least this difference value over a predefined time interval (e.g., TTT value). Preferably, the handover data consists of sets of TTT and HOM values; that is, a specific set of handover parameters (T; H) is assigned to a specific position or position data set, taking into account road data and, optionally, speed and direction data. In a further embodiment of the invention, the communication device includes a measuring unit for measuring quality data of a communication with the first base station and / or at least one signal of the first base station, wherein the communication device initiates a change of primary communication from the first to the second base station when the quality data, preferably over a trigger time interval, falls below a radio quality indication according to the transfer parameters. Due to the determination of the transfer parameters using position data, taking into account road data and optionally using movement direction data and speeds, a satisfactory determination of transfer parameters is possible for the first time, such that ping-pong effects and RLF effects are largely reduced. Furthermore, the transfer parameter determination unit is preferably signal-connected to the position determination unit and the radio transmitting / receiving unit, so that the transfer parameters can be transmitted to the radio transmitting / receiving unit. The above-mentioned task is further solved by a system comprising at least two base stations, each providing at least two remote communication cells or radio communication cells and equipped for radio communication with at least one communication device. The described system comprises at least one base station with a receiver unit for receiving position data from the communication device. Accordingly, the position data of the communication device, determined by the position detection unit, can be transmitted to the base station. Furthermore, the system according to the invention comprises at least one storage unit for storing a plurality of transfer parameters depending on position data, wherein the system is configured to select transfer parameters for the at least one communication device based on the position data. In a further embodiment of the invention, the system can take into account, when selecting the transfer parameters, data relating to a road course and / or data relating to the radio wave propagation of at least one of the base stations and / or data relating to a maximum speed and / or average speed associated with a road on which the communication device is located. In a further embodiment of the invention, data relating to the radio wave propagation of at least the currently operating base station and the intended future base station are taken into account when selecting the transfer parameters. This allows a communication device to determine its position, retrieve the corresponding street data from its memory, and derive the transmission parameters from this information. Conversely, the base station can use the transmitted position data and street data to determine the communication device's transmission parameters and then communicate these parameters to the device. Accordingly, at least one base station or the base station can have a transmitting unit for sending transfer parameters to the at least one communication device depending on the position data. Furthermore, it is conceivable that the data recorded by the detection unit regarding the speed and / or direction of movement of the communication device can be transmitted to one or more base stations. In summary, it is theoretically possible for the transfer parameters to be transmitted centrally or decentrally. In a centralized embodiment of the aforementioned system or communication device, at least one base station (eNB) has a memory for storing a digital map containing the transfer parameters. The communication device (UE) transmits the position or GNSS data to the base station, enabling the base station to select the transfer parameters based on the position data and the associated street data. The transfer parameters, specifically the TTT value and / or the specific HOM value, are then transmitted from the base station to the communication device using a transmitter. In a decentralized embodiment of the invention, a base station transmits the digital map, including the stored transfer parameters, to the (mobile) terminal device or communication device. Using the transfer parameter determination unit, the optimal transfer parameters can be determined based on the position data acquired by the position determination unit and the associated street data. The aforementioned task is further accomplished by a vehicle equipped with a communication device, as previously described. This vehicle may include a navigation system that determines and provides the position data. Similar advantages arise as those already described in connection with the system or the communication device. The invention is described below by means of several exemplary embodiments, which are explained in more detail with reference to illustrations. Figure 1 shows a system with a first and a second base station and a communication device, wherein the communication device is designed such that communication between the communication device and both base stations is possible; Figure 2 shows components of a communication device; Figure 3 shows a schematic representation of two base stations and two extended remote communication cells with a communication device located in one of the remote communication cells; and Figure 4 shows an assignment table that assigns transfer parameters to each position in conjunction with recorded speed and direction data. In the following description, the same reference numbers are used for identical and equivalent parts. Figure 1 shows a system with a first base station 10 and a second base station 20. A vehicle 30 is also provided. The vehicle 30 is located on a road within a radio cell 11 established by the base station 10. The second base station 20 also establishes a radio cell 21. The vehicle 30 is designed to communicate with both the first base station 10 and the second base station 20. In the embodiment shown in Fig. 1, communication – a data and / or voice connection – is currently established between the first base station and the vehicle 30. The vehicle 30 is located on a road leading towards the second base station 20 and thus towards the second radio cell 21. According to the communication device or method according to the invention, handover parameters must be defined or determined so that a handover of the vehicle 30 from the first radio cell 11 to the second radio cell 21 can be carried out. This handover does not necessarily have to take place at the boundary 25 between the two radio cells.Rather, the invention uses knowledge of the road's course and / or the vehicle's speed and / or the maximum and / or average speed of the road to perform an optimal handover. According to Fig. 2, the vehicle 30 is shown, which, according to the invention, has a communication device 40 comprising, as shown, a radio transmitter / receiver unit 41, a transfer parameter determination unit 42, and a memory 43. This memory 43 can also be located in the base station 10 or 20 or in a higher-level system. The vehicle 30 also has a GNSS module 50 that supplies position data (PosData) to the communication device 40. This position data (PosData) could, for example, be an identification number that specifies a particular section of a specific street in a particular city in a particular country. According to the invention, a road data mapping table is stored in the storage device 43, which makes it possible to link the position data with road data. The road data can be data relating to the road course and / or data relating to the radio wave propagation of the base station(s) and / or the maximum speed and / or the average speed assigned to the road on which the communication device 40 or the vehicle 30 is located and / or road map data. Accordingly, each position on a section of a road is assigned both a prescribed maximum speed and a statistically determined average speed. The road layout or road map data can also be stored in the memory 43. Optionally, the vehicle 30 can have a detection unit 60 for recording the vehicle's current speed 61 and its direction of travel 62. The data from the detection unit are transmitted to the communication device 40, in particular to the transfer parameter determination unit 41, so that the transfer parameters (T; H) can be determined depending on the position and the associated road data, as well as the vehicle's current speed and direction of travel.In a preferred embodiment of the invention, optimized transfer parameters for the respective road and / or road segment are already stored in the memory 43. These transfer parameters can be calculated or determined in an iterative process. In one embodiment, the communication device 40 performs the task of determining the characteristic data of the road 71 (route, average speed, etc.). In another embodiment, a navigation system provides all or some of the characteristic data. Theoretically, it would also be conceivable that the digital road map of a navigation system contains the transfer parameters (H, T) and provides these to the communication device 40 continuously or on request. As shown in Fig. 3, the vehicle 30 is located on a road 70, which leads from a first radio cell 11 to a second radio cell 21. Also shown are the first base station 10 and the second base station 20, as well as another road 71 located within radio cell 11. The depicted position (PosData) of the vehicle 30 is linked to road data (StrData). Accordingly, the maximum speed at this position is 100 km / h. The statistically determined average speed, however, is 82 km / h. Furthermore, road data relating to the road's course and the radio wave propagation or radio wave strength of the base stations are stored in the respective base station memories 13 and 23. In the described embodiment, both the road data (StrData) and the transfer parameters are stored in the base station memories 13 and 23.As already explained, it is also conceivable to store some or all of this information locally in the respective vehicle 30 or in a central database used by several base stations. In the described embodiment, the position data (PosData) is determined by the GNSS module 50. Theoretically, however, it is also conceivable that the base station determines the position data of the vehicle 30. For example, the position data can be determined by triangulation using several base stations. The vehicle 30 according to Fig. 3 includes a detection unit 60 for detecting the current speed 61 and the direction of movement 62 of the vehicle. The direction 62 therefore indicates that the vehicle 30 is moving eastwards on road 70 in the direction of the long-distance radio cell 21. Fig. 4 shows a corresponding allocation table for determining the transfer parameters, which determines at what time the vehicle 30 is transferred from the first radio cell 11 to the second radio cell 21, whereby this transfer does not necessarily have to take place at the boundary 25 between the two radio cells. The assignment table illustrates that eleven position data points can result in connection with radio cell 11, in which vehicle 30 is located. In this case, position 3 is occupied within the radio cell. This position 3 indicates that the vehicle is located on state road 70 in long-distance communication cell 11. Specifically, the vehicle is on road 70 in section 2. The maximum permitted speed in this section is 100 km / h, with an average speed of 82 km / h. Using the detection unit 60, the direction of travel 62 "East" was determined. The current speed 61 is 95 km / h, so the handover parameters TTT value = 1.7 and HOM value = 3.0 are determined. The handover parameters (1.7; 3.0) are transmitted to the radio transceiver unit so that an optimized handover can be carried out. Theoretically, it would be conceivable to perform a quality measurement regarding the handover of vehicle 30 to the second radio cell 12 of the second base station 20, whereby the handover was carried out based on the modified TTT value of 1.7 and the modified HOM value of 3.0. Theoretically, it is conceivable that a comparison of the measured handover quality with a stored handover quality could then be carried out to optimize future handovers. The individual embodiments described can be combined in various ways according to the invention. Reference symbol list 10 First Base Station 11 First Cell 13 Memory 20 Second Base Station 21 Second Cell 23 Memory 25 Boundary 30 Vehicle 40 Communication Device 41 Radio Transmit / Receive Unit 42 Transfer Parameter Determination Unit 43 Memory 50 GNSS Module 60 Acquisition Unit 61 Current Speed ​​62 Direction 70 / 71 Road

Claims

Method for communication between a communication device and at least one first (10) and one second (20) base station, comprising the steps of: a) establishing a voice and / or data connection between the communication device and the first base station (10); b) determining / receiving position data (PosData) of the communication device (40), wherein the position data (PosData) includes street data (StrData); c) determining / receiving handover parameters based on the street data (StrData), wherein the handover parameters are a handover trigger time interval, namely at least a TTT value, and radio quality information, namely at least a HOM value; d) handing over a voice / data connection to the second base station (20) taking into account the determined / determined handover parameters;and storing a modified TTT value and a modified HOM value together with transfer qualities that specify the quality of the transfer from the first (10) to the second base station (20), wherein the modification of the TTT value and the HOM value includes an optimization, minimizing a data loss rate (Rout(θ)) for a given number of ping-pong transfers (Rpp(θ)). Method according to claim 1, characterized by,e) capturing / receiving the movement speed data and / or movement direction data of the communication device, wherein this data is taken into account when determining the transfer parameters. Method according to one of claims 1 - 2, characterized by f) transmission of the TTT value and / or the HOM value from a base station to a communication device and g) modification of the TTT value and / or the HOM value from the communication device. Method according to one of claims 1-3, characterized by, i) quality measurement with regard to the handover of the communication device to a second radio cell of a second base station based on a / the modified TTT value and / or a / the modified HOM value; j) comparison of the measured handover quality with stored handover qualities to optimize future handovers. Communication device (40), in particular a (mobile) terminal device, for communication according to a method according to one of claims 1 to 4, comprising: - at least one position determination unit (50) for determining position data (PosData) of the communication device; - at least one radio transmitting / receiving unit (41) for communication with at least one first (10) and at least one second (20) base station; - at least one transfer parameter determination unit (42) for determining transfer parameters, characterized in that the transfer parameter determination unit (42) transmits the position data (PosData) to one of the base stations and / or identifies the transfer parameters in a memory based on the position data (PosData), wherein the position data (PosData) are linked with street data (StrData). Communication device according to claim 5, characterized by a detection unit for detecting (60) the movement speed data (61) and / or movement direction data (62) of the communication device, wherein this data is taken into account when determining the transfer parameters. Communication device according to claim 5 or 6, characterized in that the transfer parameter determination unit (42) takes into account, when determining the transfer parameter data relating to a road course and / or data relating to the radio wave propagation of at least one of the base stations and / or data relating to a maximum speed and / or data relating to an average speed associated with a road on which the communication device is located. Communication device according to one of claims 5 to 7, characterized in that the transfer parameters are the trigger time interval, in particular at least one TTT value, and / or radio quality information, in particular at least one HOM value. Communication device according to one of claims 5 to 8, characterized by a measuring unit for measuring quality data of a communication with the first base station and / or at least one signal of the first base station, wherein the communication device initiates a change of primary communication from the first to the second base station when the quality data, preferably over a trigger time interval, falls below a radio quality specification according to the transfer parameters. System for carrying out a method according to one of claims 1 to 4, comprising: - at least two base stations (10; 20) which span at least two radio cells (11; 21) and are configured for radio communication with at least one communication device (40), in particular according to one of the preceding claims; - at least one receiving unit for receiving position data (PosData) from the communication device; - at least one storage unit for storing a plurality of transfer parameters depending on position data, wherein the system is configured to select transfer parameters for the at least one communication device based on the position data (PosData). System according to claim 10, characterized in that the system, when selecting the transfer parameters, takes into account data relating to a road course and / or data relating to the radio wave propagation of at least one of the base stations and / or data relating to a maximum speed and / or data relating to an average speed associated with a road on which the communication device is located. System according to one of claims 10 or 11, in particular according to claim 11, characterized in that at least one base station has a transmitting unit for sending transfer parameters to the at least one communication device depending on the position data. Vehicle (30) with a communication device (40) according to one of claims 5 to 9, wherein the position determination unit is a navigation system.

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