RU2772978C2 - Reduction in interference created by aircrafts - Google Patents

Abstract

FIELD: communication.

SUBSTANCE: group of inventions relates to communication technology; it can be used in mobile communication systems created by aircrafts, in particular unmanned aerial vehicles. A method includes control of direction of a radio transmission of an aircraft in the air, at which vertically downward direction of the transmission is provided.

EFFECT: increase in noise immunity of communication due to the compensation of effects caused by changing inclination angles of a drone during the flight and impacting on the direction of the axis of a directional diagram of directed antennas.

15 cl, 8 dwg

Description

Technical field

The present invention relates to methods for reducing interference in a mobile communication system caused by aircraft, in particular unmanned aerial vehicles, commonly referred to as "drones".

State of the art

At the 3GPP RAN Plenary Meeting #75 in March 2017, a new subject of study for the RAN working groups, "Enhanced Support for Aircraft", was considered and approved. The feasibility of including this subject of study in the scope of 3GPP is associated with the growth in the number of drones (or unmanned aerial vehicles, UAVs) that are (or can be equipped) with mobile communication devices (user devices, (UE, user equipment)). This trend is driven by the existence of two types of drones, namely drones that can mount regular cell phones on them, and drones available on the market that are equipped with built-in cellular modems.

Drones are expected to grow particularly rapidly in package delivery, search and rescue, critical infrastructure monitoring, wildlife conservation, video surveillance, and as flying cameras. Most likely, these use cases will continue to appear in the coming years. In many of the use cases mentioned above, there may be some benefit from connecting drones to cellular systems (eg, LTE networks) as UE devices. As a result, in the future, a large fleet of drones with cellular modems may be added to the existing fleet of UEs operating on the earth's surface (or near it). Therefore, some mobile network operators (MNOs, Mobile Network Operators) feel the need to better prepare their existing cellular networks for the upcoming increase in data traffic caused by the proliferation of drones equipped with cellular modems.

For example, at low altitudes, a UE-equipped drone usually behaves like a traditional UE, but at high altitudes, the radio wave propagation characteristics change and the drone uplink signal may cause problems because it can be received by a large number of cells due to line-of-sight radio wave propagation. .

The uplink signal transmitted by such a flying drone significantly increases the interference to the uplink signals received in neighboring cells, as shown in FIG. 1. Thus, the drone's uplink signal has a negative impact on other UEs located or installed on the surface of the earth (for example, a smartphone, an IoT device, etc.).

The main difference between the uplink signals transmitted by flying drones and the signals transmitted by traditional UEs at zero altitude is the significant difference in their radiation pattern, and for this reason, the radiation patterns used in the network planning stage are not applicable. This is mainly due to the fact that when the UE (drone) is located at a higher altitude, there are fewer obstacles between it and neighboring cells that weaken the signal. It may well be that a flying drone served by a single cell creates interference in a cell of the second or third range level that is considered impossible for UEs at zero altitude. In other words, the prediction of interference in a cell from UEs served by other cells is quite different for flying UEs compared to UEs at zero altitude. As a result, cell scheduling becomes sub-optimal and uplink connections are highly vulnerable to interference from UEs operating at high altitude. These facts have been studied and served as the basis for the development of the mentioned 3GPP documents, so the impact described here should be taken seriously by network operators.

In addition, a highly visible drone uplink signal can create problems for direct device connection (SL, sidelink), for example, D2D (device-to-device) or V2V (vehicle-to-vehicle) communication, since all interface traffic PC5 (of the UE-to-UE interface) is allocated to the uplink resources, i.e. the same uplink carrier frequencies that are intended for transmission in the uplink of LTE-FDD systems, and the same uplink subframes that are intended to be transmitted in uplink of LTE-TDD systems. In FIG. 2 shows interference from drone uplink signals in the SL channel established between two UEs engaged in D2D (or V2V) communication in a neighboring cell.

Currently, LTE base stations (eNBs) have two means of limiting or eliminating uplink interference from UEs served by a neighbor cell, an overload indicator (OI, Overload Indicator) and a high interference indicator (HII, High Interference Indication).

An eNB that detects a high level of interference on any uplink resource may transmit an "Overload Indicator" (OI) to neighboring cells. The message includes an indication of the affected radio resources. The neighbor cells should then try to provide other resources to the UE that is currently using such a resource.

An eNB wishing to allocate resources to the uplink to transmit high power signals may transmit a high interference indicator (HII) to neighbor cells with the affected radio resource identifier. Neighbor cells that have received it should try to avoid allocating these resources.

Another modern means of preventing the influence of interference is the use of methods for forming an appropriate radiation pattern, i.e. beam orientation when transmitting signals of the UE installed on the drone towards the eNB of the serving cell. This is a more complex method that requires frequent reconfiguration of the adaptive antennas, as the direction of the beam axis must constantly be adjusted as the aircraft moves. In addition, periodic exchange of control information between the UE and the eNB is required. When forming the radiation pattern, the following definitions are used:

- eNB-Tx-beam: high-gain antenna configuration for directional downlink (DL, downlink) transmission in the eNB station, used to transmit signals from the tower to the mobile phone;

- eNB-Rx-beam: high-gain antenna configuration for directional uplink (UL, uplink) reception in an eNB station, used to receive signals transmitted from a mobile phone to a tower;

- UE-Tx-beam: uplink directional antenna gain configuration in the UE used to transmit signals from the mobile phone to the tower;

- UE-Rx-beam: Antenna up-gain configuration for downlink directional transmission in the UE used to receive signals transmitted from the tower to the mobile phone;

- directional downlink: downlink connection with TRP-Tx-beam and UE-Rx-beam configurations;

- directed uplink: uplink connection with UE-Tx-beam and TRP-Rx-beam configurations.

From the patent literature, methods are known for controlling the angle of inclination of the antenna axis (US 20120015684 A1) and the width of the antenna pattern (JP 2004229220 A) of the base station depending on the height of either the base station antenna itself or the terminal (UE device). Antenna adaptation is performed to orient the antenna beam axis to the UE and to reduce interference to other devices or cells. There is no information in the patent literature about adapting the beamwidth autonomously in the UE, i.e. without specially provided signaling by the base station. In addition, the expected cell size is not taken into account when calculating beamwidth. Also, the order of the step-by-step configuration is unknown.

From patent document EP 2994958 A1 a method is known in which the width of the radiation pattern, the axis of which is directed towards the ground, is dynamically adjusted depending on the height of the aircraft (balloon) on which the communication device is installed. This patent also does not take into account the expected size of the serving cell when calculating beamwidth.

US 20070161347 A1 describes an aircraft-mounted mobile communication system that acts as a relay for UEs on board an aircraft. The antenna is mounted on the underside of the aircraft fuselage and is oriented vertically downwards in level flight, but its orientation is not controlled relative to the orientation of the aircraft. The radio direction control is not performed.

US Pat. No. 5,699,069 describes an aircraft-mounted communication system. This system includes several antennas oriented in different directions and provides for the formation of electromagnetic radiation patterns with different orientations to provide a wide coverage area. Information about the possibility of controlling individual radiation patterns is not given.

Patent document WO 2016028767A1 describes an aeronautical communication system comprising several airborne nodes providing coverage for users on the earth's surface. These airborne nodes are indicated to transmit vertically downwards, but there is no indication that this is achieved by beam steering rather than by proper orientation of the transmitting antenna.

US 20170013476 A1 describes a drone carrying a radio station that functions as a mobile cellular communications node. The drone has a directional antenna that can be pointed towards the ground, but there is no indication that the radiation pattern is controllable.

Disclosure of invention

One aspect of the present invention relates to compensating for effects caused by changes in aircraft pitch angles during flight that affect the direction of the beam axis of directional antennas. The lateral position and/or speed of the aircraft can be controlled by maintaining and/or varying the power of one or more of the aircraft's propulsion systems. The rotation speed of one or more of the aircraft propellers can affect the lateral movement of the aircraft. For example, in order for the aircraft to move in a certain direction, it can be tilted in that direction, while the speed of rotation of the drone's propellers can affect the lateral speed and/or the trajectory of movement. When the aircraft tilts to change its lateral position and/or speed, the antenna system of the UE attached to or integrated in the aircraft also tilts in most cases such that the beam axis orientation is directly on the ground (i.e., perpendicular to the ground). ground) is violated. Therefore, another aspect of the present invention is a function of autonomously controlling a UE to adjust its uplink beam pattern orientation (i.e. UE-Tx-beam) and/or its downlink beam orientation (i.e. UE-Rx-beam ).

Currently available interference mitigation tools (OI and HII) are not able to solve this problem with respect to interference from UEs operating at high altitude, since it is likely that the nearby neighboring cells are not serving the interfering UEs. And this UE can be served by a neighbor cell of the second or third (etc.) range order, and therefore neither OI nor HII signals are received by the serving cell. The obvious solution to the problem by transmitting OI and HII to cells of the next range order unnecessarily complicates existing interference suppression techniques.

Another reason for the inoperability of OI and HII technologies is the difference between the power level of UE drones and the power level of UE devices at zero altitude, which can cause interference. In some cases, the uplink transmit power of the UE drone is below the threshold above which the HII signal is transmitted. Therefore, the HII signal is not transmitted while this UE drone is interfering. The affected eNB can then use the OI signal, but interference has already occurred and data may already be lost with a high probability.

Due to the nature of drones, uplink interfered cells and direct-connect interfered UEs are dynamically replaced by others. Therefore, a large amount of signaling is required for the transmission of HII and OI signals.

In addition to these problems in uplink interference suppression, HII and OI signals are not suitable for direct-connect channel interference suppression.

Using beamforming techniques reduces interference but comes at a cost: adjusting the direction of the beam axis requires periodic transmission of control signals between the UE and its serving eNB. At the same time, the speed of such adaptation must be increased with increasing drone speed. Therefore, this option is not suitable in cases where the aircraft is moving quickly, but even if the aircraft is not moving at all, a large amount of calculation and signaling is required to maintain the correct direction of the beam axis.

Known solutions that use a downward-facing UE-Tx-beam (eg EP 2994958 A1) do not adapt the beamwidth according to the radius of the serving cell. Therefore, after handover to a new serving cell, the selected beamwidth is not optimal. This results in either an increase in interference power if the beam pattern is too wide, or a deterioration in the quality of the link if the beam pattern is too narrow.

The present invention implements a method for reducing interference generated by an aircraft in a mobile communication system. The method includes organizing radio transmission control in an airborne aircraft, in which the direction of transmission is adjusted so that it is carried out vertically downwards.

It is advisable to use a stand-alone device to control the orientation of the radiation pattern, which does not require the transmission of signals from the base station.

The UE attached to the aircraft is equipped with adaptive antennas that allow the width and direction of the UE-Tx-beam (and/or UE-Rx-beam) to be autonomously adjusted without transmitting control signals to the base station, while the direction of the beam axis is adjusted so that it was facing the ground perpendicular to it, regardless of the tilt of the aircraft, using the plumb function, and the beamwidth is calculated based on the estimated radius of the serving cell to provide coverage equal to the radius of the serving cell on the ground.

The advantage of adaptive beamforming is that interference caused by high altitude operation of the UE is suppressed because the received signal strength in neighboring cells is reduced. Therefore, the user and the network benefit from improved connection reliability and increased system throughput. In addition, the amount of signaling and the composition of the corresponding actions for generating messages for network interference suppression methods using OI and HII signals are significantly reduced and, therefore, computing and communication resources are saved. In most cases, UE drones no longer require OI and HII signals.

It is proposed to actively stabilize the beam axis in the vertical direction towards the ground. This method is very easy to implement and has no impact on the mobile communication network and eNBs. Signaling is not required. Therefore, this method saves battery and radio resources.

The beamwidth can be controlled based on a height measurement above the ground and based on the footprint range (FPR) of the serving cell. The antenna system of a UE drone can be controlled so that the beamwidth during transmission (and, if necessary, also during reception) gradually decreases as the aircraft's flight altitude increases. Here, the goal is to limit the coverage area on the earth's surface provided by the uplink beam pattern of the drone. Similarly, as the aircraft's height above ground level decreases, the uplink (and downlink, if necessary) beam pattern of the aircraft can gradually widen.

Height can be determined by the drone in many ways, for example:

- based on the analysis of images taken by the camera mounted on the drone, which in most cases is still filming from the drone, and therefore only a small amount of additional calculations are required to determine the height from these images;

- based on data from one or more echolocation sensors commonly used by drones;

- based on signals or information from terrestrial communication systems, for example by measuring the angle of reception of signals from transmitters (including cellular base stations, such as eNB stations) with a known location;

- based on the measurement of air pressure drop. To do this, an air pressure sensor is attached to the drone, which measures the pressure at ground level (for example, before launch or when propellers are launched) and periodically during flight. Altitude can be calculated from the "barometric formula", assuming that the pressure drops by approximately 11.3 Pa per meter at altitudes up to 1000 meters above sea level;

- based on data from satellite navigation systems, such as GPS, GLONASS, Galileo or Beidou.

Summary of drawings

Hereinafter, by way of example only, preferred embodiments of the invention are described with reference to the accompanying drawings.

In FIG. 1 shows a situation where a drone can interfere with a neighboring cell.

In FIG. 2 shows a situation where a drone may interfere with a direct connection channel for UEs operating in a neighboring cell.

In FIG. 3 shows the change in beamwidth as a function of altitude.

In FIG. Figure 4 shows the control of the drone coverage area depending on the cell radius.

In FIG. Figure 5 shows the control of the drone's coverage area depending on the maximum transmission distance.

In FIG. 6 shows the change in beamwidth depending on the power parameter of the received signal.

In FIG. 7 shows the steps taken to implement the method according to the present invention.

In FIG. 8 shows the change in the direction of the axis of the radiation pattern depending on the angular position of the drone.

Implementation of the invention

In the first embodiment of the invention, the coverage area radius (FPR) is calculated using the indication of the transmission range of the serving cell (equal to the cell radius) as shown in FIG. 4. The beamwidth is then adjusted based on the aircraft's altitude to provide a coverage radius nearly equal to that of a cell. For example, in an LTE system, the cell radius can be estimated from the "reference signal power" (P _Ref ). This parameter represents the transmission power of the reference signals in the downlink of a particular cell. It is broadcast by every cell in the System Information Block (SIB) type 2, and the power range is from 60 dBm to +50 dBm. Equation (1) can be used to calculate the FPR value. It takes into account the propagation loss calculated from a propagation loss model such as that described at www.wirelesscommunication.nl/reference/chaptr03/pel/loss.htm:

where

FPR is the radius of the coverage area defined by the transmitting radiation pattern of the UE drone;

D ₀ - constant coefficient equal to 748 1/m ² *MHz;

P _ref is the power of the reference signal broadcast by the eNB;

f _c is the downlink carrier frequency in MHz indicated by the eNB;

B _DL - downlink data transmission energy balance at 24 dBm transmission power, calculated according to the method described in the LTE online encyclopedia at https://sites.google.com/site/lteencyclopedia/lte-radio-link-budgeting- and-rf-planning. Typically, the UE does not know all the parameters needed to calculate the channel energy balance. In this case, the missing parameters are taken equal to those used in the example given in the LTE encyclopedia. If no parameter is known, or a rough estimate is considered sufficient for simplicity, a value of 165.5 dBm may be used for B _DL (see Table 1);

C _DL is a constant factor ranging from 0.1 to 10 used to adapt the FPR value to the cell radius. A value of "1" means that the FPR value is equal to the cell radius. This value is either preset in the UE or transmitted to the UE by the mobile network.

In the second embodiment of the invention, the coverage area radius (FPR) of the drone is calculated to be less than or equal to the maximum transmission range of the UE at zero altitude, as shown in FIG. 5. The maximum transmission range of the UE at zero altitude for a given serving cell can be estimated, for example, in the LTE system, based on the parameter P _MAX . This is the maximum transmit power of the UE for a particular cell. It is broadcast by every cell in SIB1. Equation (2) can be used to calculate the FPR value. It takes into account the propagation loss calculated from a propagation loss model such as the one described at www.wirelesscommunication.nl/reference/chaptr03/pel/loss.htm:

where

FPR is the radius of the coverage area defined by the transmitting radiation pattern of the UE drone;

D ₀ - constant coefficient equal to 748 1/m ² *MHz;

P _MAX is the maximum transmission power of the UE broadcast by the eNB;

f _c is the uplink carrier frequency in MHz indicated by the eNB;

B _UL is the energy balance of data transmission in the uplink at a transmission power of 24 dBm, calculated according to the method described in the above-mentioned LTE encyclopedia. Typically, the UE does not know all the parameters needed to calculate the channel energy balance. In this case, the missing parameters are taken equal to those used in the example given in the LTE encyclopedia. If no parameter is known, or a rough estimate is considered sufficient for simplicity, a value of 149.5 dBm can be used for B _UL (see Table 2, where data rate 64 kbit/s is used instead of 64 kbit/s to create conditions similar to those for the downlink. 1 Mbps);

C _UL is a constant factor between 0.1 and 10 used to adapt the FPR value to the maximum transmission range of the UEs at zero altitude. The value "1" means that the FPR is equal to the transmission range of the UEs at zero altitude. This value is either preset in the UE or transmitted to the UE over the mobile network.

In the first and second embodiments of the invention, the FPR value is calculated individually for each cell. In the third embodiment of the invention, the FPR radius has a semi-static value, which is known in advance by the UE drone and which can be further configured over the network. Beam width (BW) can be calculated according to equation (3). This principle is illustrated in Fig. 3.

The first three embodiments of the invention are characterized by a rather low rate of change in the beamwidth of the adaptive antenna system. For example, if the flight altitude of the drone remains constant, then after handover to another cell, if it uses a different cell radius, only one beamwidth adaptation cycle may be required. Alternatively, adaptation is not required until the aircraft leaves a certain altitude corridor. This applies to the case where no cell-specific beamwidth adaptation is used, or when the cell radius remains the same in the new cell. Therefore, this method is best suited for drones that usually fly at a constant altitude, such as delivery drones, but it also works for all other types of drones. The overhead (eg, battery power consumption and processor resources) for implementing this method is very small.

In the fourth embodiment of the invention, the beamwidth of the UE-Tx-beam is adjusted according to the strength of the signal received from the serving cell or neighboring cells. Therefore, the UE drone performs a signal strength measurement received from the selected base station. In the case of an LTE base station (eNB), Reference Signal Received Power (RSRP) can be used (see 3GPP TS 36.214). In the case of using a neighbor cell, it selects the best neighbor cell (eg, the cell with the highest RSRP value). For this measurement, the UE drone first uses a wide UE-Rx-beam, which ensures that the cell that is being measured falls within this beam. The UE drone then repeats the measurement in the selected cell with decreasing beamwidth. It performs further measurements with a corresponding reduction in beamwidth until the difference between the measured RSRP value and the result of the initial measurement (in which a wide beam was used) is less than some predetermined value (for example, 3 dB). The UE-Rx-beam beamwidth of the last measurement is also used for the UE-Tx-beam beam of the UE drone, provided that reception at the serving base station is not affected (this can be ensured by making these measurements very quickly, for example, within a few seconds). The measurement of the RSRP value is performed periodically and allows the beamwidth to be adapted accordingly. If it is necessary to make measurements in neighboring cells, they must be made using a wide radiation pattern. In addition, a fixed or adjustable ratio R (for example, in the range from 0.6 to 1.0) between the width of the beams UE-Tx-beam and UE-Rx-beam can be determined, for example, in accordance with formula (4):

In the fifth embodiment of the invention, beamwidth control and change is performed similarly to the previous embodiments of the invention. In this case, the axis of the radiation pattern is not oriented vertically towards the ground, but is directed towards the base station. This ensures that the maximum antenna gain is used for communication with the base station, which reduces the required transmit power and thus reduces the interference generated in other cells. The deflection angle can be estimated by measuring the reception angle or by estimating the geographic location of the UE relative to the base station.

In one embodiment of the present invention, the drone is equipped with means to autonomously maintain the vertical direction of the ground plane during various maneuvers in flight, compensating for the tilting movements that the drone may make during acceleration or deceleration, or, in general, lateral movement. This function, called the "plumb line" function, used to stabilize the direction of the axis of the radiation pattern, can be implemented using inertial sensors, gyroscopes, magnetometers or other types of sensors, while drones can keep the angle α between the direction of orientation of the antenna system and downward virtual plumb line, as shown in FIG. eight.

It should be noted that the beamwidth discussed above refers to antennas used for transmission, i.e. for UE-Tx-beam beamforming. In most cases, the same antenna characteristic can be used for reception, i.e. the computed parameters can be used to tune the antennas at the UE's receiver (for UE-Rx-beam beamforming). If different base stations are used for uplink and downlink at different locations, and in some cases if the downlink and uplink carrier frequency spacing is very large, this approach may not be useful. In addition, performing downlink measurements using the directional response of the antenna may lead to unexpected results. Therefore, for measurement purposes, it is recommended to use a non-directional characteristic.

In the example below, it is assumed that the UE drone is served by a mobile network based on an LTE system. However, the principles of the present invention are applicable to another type of mobile communication system such as GSM, UMTS or any new type such as 5G.

The aircraft is equipped with a UE device, and its antennas are designed for directional signal transmission down to the ground. The tunable radiation pattern can be 10° to 180° wide, or it can be omnidirectional.

The beamwidth adjustment procedure is described below. The drone flight path for this example is shown in Fig. 7. The circled numbers in the figures correspond to the numbering of the steps below.

1. Drone (including UE drone) turns on. The UE drone connects to the mobile communication network through eNB A. It receives a P _Ref power reference signal from eNB A and uses an omnidirectional antenna for transmission and reception.

2. Drone takes off. It starts tracking altitude (for example, with an acoustic sensor). It is pre-configured to the altitude threshold Alt _min (pre-stored in the UE or configured over the network). In this example, eNB A sends Alt _{min, cell_A} =20 m to the UE drone. This means that in this example, each cell can select a UE drone setting with a different Alt _min parameter value. As long as this threshold is not exceeded, the UE drone will operate with an omnidirectional antenna.

3. The drone is gaining altitude. Upon detecting that the altitude has exceeded Altmin, it turns on the beamwidth control function, i.e. calculates the FPR value according to formula (1), which is valid within the current serving cell, i.e. no additional calculations are required until the next handover. Next, it calculates the beamwidth of BW _{cell A} given the current height and the FPR value according to equation (3). This is done either periodically (for example, once per second) or on an event, when the difference between the current altitude and the altitude used for the previous calculation exceeds a certain value. The latter is most effective if the drone is at a constant altitude.

4. During the flight, the UE drone performs neighbor cell measurements in the usual manner for the UE device. Such measurements are made with an omnidirectional antenna.

5. At some point in time, these measurements indicate the need to handover to cell B. Then the UE drone performs a handover to cell B as usual. In addition, the drone UE receives P _Re f and Alt _{min, cell_B} from eNB B.

6. The drone UE uses the newly received parameter P _Ref to calculate the FPR value and beamwidth BW _{cell B} . In the example in FIG. 7, the value of P _Ref of cell B, and hence the radius of this cell, is much larger than the value of P _Ref of cell A. Therefore, after handover, the FPR value will be much larger.

7. The aircraft approaches the landing area and begins to descend.

8. The UE drone detects that the current height is less than Alt _{min, cell_B} . Therefore, it turns off the beamwidth control function. It now uses the non-directional antenna characteristic.

9. Drone lands and turns off.

Downlink Energy Balance (or "Maximum Propagation Loss") at 1 Mbps in the case of a terminal receiver with two antennas (from "LTE Encyclopedia").

Uplink Energy Balance (or "Maximum Propagation Loss") at 64 kbps in the case of a base station receiver with two antennas (from "LTE Encyclopedia").

Claims (15)

1. A method for reducing interference generated by an aircraft in a mobile communication system, which includes controlling the directionality of a radio transmission of an aircraft in the air to compensate for the inclination of the aircraft, in which the direction of transmission is adjusted in a vertically downward direction and the aircraft adapts the beamwidth of the radio transmission , controlling the ground coverage radius for that radiation pattern relative to the cell size of the base station communicating with that aircraft. 2. The method of claim 1, wherein the beamwidth is adapted based on the measured height of the aircraft above the ground and depending on the size of the cell. 3. The method of claim 1 or 2, wherein the received power parameter of the reference signal is used to determine the cell size. 4. The method of claim 1, wherein the aircraft comprises a user device module equipped with an adaptive antenna and a self-contained device for controlling the antenna pattern and controlling the width of the radio transmission pattern such that the radius of the coverage area on the earth's surface for that pattern is adjusted relative to the estimated transmission range of a user device operating at ground level. 5. The method of claim 4, wherein the received maximum transmit power parameter is used to determine the estimated transmission range value. 6. The method of claim 1, wherein the aircraft comprises a user device module equipped with an adaptive antenna and a self-contained device for controlling the antenna pattern and controlling the width of the radio transmission pattern such that the radius of the coverage area on the earth's surface for that pattern is adjusted relative to preset value. 7. The method of claim 1, wherein the aircraft comprises a user device module equipped with an adaptive antenna and a self-contained device for controlling the antenna pattern and controlling the width of the radio transmission pattern such that the radius of the coverage area on the earth's surface for that pattern is adjusted relative to the strength of the received signal from the selected base station of the mobile communication system. 8. The method of claim 7, wherein the aircraft comprises a user device module equipped with an adaptive antenna and a self-contained antenna beam steering device that measures received signal strength from a selected base station and changes the selected receive beamwidth until the received signal strength will not fall below a predetermined threshold, and the receive beamwidth at which the received signal power falls below a predetermined threshold is used as the beamwidth when transmitting radio signals from the aircraft. 9. The method according to any one of paragraphs. 1-8, which uses the measured height of the aircraft above the ground to control beamwidth. 10. A method according to any one of the preceding claims, wherein the measured position of the aircraft in flight is used to control the direction of the transmission. 11. A method according to any one of the preceding claims, wherein the directionality control of the radio transmission is initiated when the height of the aircraft above the ground exceeds a predetermined value. 12. An aircraft comprising a user device module equipped with an adaptive antenna and a self-contained device for controlling the antenna pattern and configured to implement the method of any one of claims 1-11. 13. A method for reducing interference generated by an aircraft in a mobile communication system, including controlling the direction of a radio transmission of an aircraft in the air to compensate for the inclination of the aircraft, in which the transmission direction is adjusted in a vertically downward direction. 14. The method of claim 13, wherein the aircraft comprises a user device module equipped with an adaptive antenna and a self-contained device for controlling the antenna pattern and controlling the width of the radio transmission pattern such that the coverage radius on the earth's surface for that pattern is adjusted relative to the estimated transmission range of a user device operating at ground level. 15. The method of claim 13, wherein the aircraft comprises a user device module equipped with an adaptive antenna and a self-contained device for controlling the antenna pattern and controlling the width of the radio transmission pattern such that the coverage radius on the earth's surface for that pattern is adjusted relative to set value.

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