WO2023033690A1

WO2023033690A1 - Providing network coverage to a vehicle

Info

Publication number: WO2023033690A1
Application number: PCT/SE2021/050850
Authority: WO
Inventors: Niklas JALDÉN; Peter ÖKVIST; Svante Bergman
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2021-09-03
Filing date: 2021-09-03
Publication date: 2023-03-09

Abstract

A method (400) for use in providing network coverage to a vehicle (191, 192). The method includes obtaining (s402) first position information indicating a first position of the vehicle. The method also includes using (s404) the first position information to obtain first directional information indicating a first direction to the vehicle from a first transmitting and receiving point, TRxP (105), of or connected to a first network node (104). And the method further includes triggering (s406) the first network node to use the first TRxP to transmit a signal in the indicated first direction.

Description

PROVIDING NETWORK COVERAGE TO A VEHICLE

TECHNICAL FIELD

[001] This disclosure relates to providing network coverage to a vehicle (e.g., an aircraft, a water vehicle, a ground vehicle, etc.).

BACKGROUND

[002] Today’s Mobile Network Operators (MNOs) supply network coverage well in densely populated areas. Several ideas are being discussed for how to develop economically feasible options for providing network coverage in less populated areas (e.g., rural areas, areas covered by large bodies of water, etc.). With such ubiquitous coverage, new services for remote monitoring using for example drones will likely increase rapidly. Given this, it is expected that future deployments will be used to supply connectivity in the air as well as on land. One of the key aspects in developing economically feasible options is to use large cells, and one enabler for this is large advanced antenna systems (AAS) and beamforming for coverage improvements.

SUMMARY

[003] Certain challenges presently exist. For instance, currently, to utilize the benefits of a multi-antenna system though beamforming, a user equipment (UE) must provide the network (e.g., the base station serving the UE) with channel state information (CSI) to enable the network to, for example, direct transmissions to the UE, but such information is typically not provided by the UE until after the UE has already established a connection (e.g., a Radio Resource Control (RRC) connection) with the network, which normally occurs after the UE has acquired certain system information (SI) provided by the network and performed the random access (RA) procedure, and/or is problematic to receive for an ongoing session for the UEs most distant from the network where the beamforming gain is needed the most.

[004] This disclosure aims at avoiding or at least mitigating the above problems. Accordingly, in one aspect there is provided a method for use in providing network coverage to a vehicle. The method includes obtaining first position information indicating a first position of the vehicle. The method also includes using the first position information to obtain first directional information indicating a first direction to the vehicle from a first transmitting and receiving point (TRxP) of or connected to a first network node. And the method further includes triggering the first network node to use the first TRxP to transmit a signal in the indicated first direction.

[005] In another aspect there is provided a computer program comprising instructions which when executed by processing circuitry of a network node causes the network node to perform any of the methods disclosed herein. In one embodiment, there is provided a carrier containing the computer program wherein the carrier is one of an electronic signal, an optical signal, a radio signal, and a computer readable storage medium.

[006] In another aspect there is provided a network node that is configured to obtain first position information indicating a first position of a vehicle and use the first position information to obtain first directional information indicating a first direction to the vehicle from a first TRxP. The network node is further configured to trigger the first TRxP to transmit a signal in the indicated first direction. In some embodiments, the network node is configured to trigger the first TRxP to transmit the signal in the indicated direction by triggering another network node (e.g., a base station or a component of a base station) to trigger the TRxP to transmit the signal in the indicated direction. In one embodiment, the network node includes memory and processing circuitry coupled to the memory.

[007] An advantage of the embodiments disclosed herein is that they improve coverage and capacity of the network, with a reduced need of uplink (UL) and downlink (DL) CSI signaling. Another advantage is that they increase coverage thereby allowing more sparse and cost-efficient deployments. A further advantage is that they reduce the signaling overhead, hence reducing the energy consumption. Yet another advantage is that they enable shorter delays in connection establishments in that beam sear ch/s weeping mechanism may be omitted since plausible (LoS) direction may be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS

[008] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate various embodiments.

[009] FIG. 1 illustrates an example environment in which a network function may be deployed. [0010] FIG. 2 illustrates an example message flow.

[0011] FIG. 3 illustrates a procedure for calculating directional information.

[0012] FIG. 4 is a flowchart illustrating a process according to some embodiments.

[0013] FIG. 5 is a block diagram of a network node according to some embodiments.

DETAILED DESCRIPTION

[0014] FIG. 1 illustrates a network function 102, according to an embodiment, that operates within an example environment 100. Environment 100 includes two network nodes 104 and 106 that are connected to at least first transmission and reception point (TRxP) 105 and a second TRxP 107, respectively. Network node 104 (denoted “NN1” in FIG. 1) may be a base station or component of a base station, such as a baseband unit (BBU) or a control unit (CU). Similarly, network node 106 (denoted “NN2” in FIG. 1) may be base station or a component of base station. Environment 100 also includes a radar system 112 for tracking the positions of aircraft (e.g., airplane 191 and airplane 192) and an location information server (LIS) 113 (e.g., an air traffic control (ATC) system) that receives position information from radar system 112 and stores the position information in a database 114. That is, for example, database 114 may store first position information identifying a current position of airplane 191 and second position information identifying a current position of airplane 192.

[0015] Advantageously, network function 102 is configured to obtain position information of vehicles (e.g., aircrafts 191 and 192) from LIS 113 or from the vehicles themselves. The obtained position information for a vehicle is used by network function 102 to obtain directional information (e.g., two angles: azimuth 0 and elevation (|>) indicating a direction to the vehicle from at least a first TRxP (e.g,. a TRxP selected by the network function based on, for example, the position of the TRxP and the position of the vehicle). Once the directional information is obtained, the network function 102 can trigger a network node (e.g., the network node that includes the TRxP or that is connected to the TRxP) to employ the TRxP transmit in the indicated first direction at least one signal (e.g., a signal containing system information that a UE in the vehicle requires to establish a logical connection with the network node, such as an RRC connection). In this manner, network function can improve the network coverage for UE’s in the vehicle because the network can use beamforming to generate a beam that covers the vehicle (see, e.g., beam 121 that provides coverage to airplane 191 and beams 122 and 123 that provide coverage to airplane 192) before the network receives any message (e.g., CSI report or random access preamble) from any of the UEs.

[0016] FIG. 2 is a message flow diagram illustrating a process according to one embodiment.

[0017] As shown in FIG. 2, LIS 113 (e.g. an ATC system) receiving from radar system 112 position information (PI) for each aircraft detected by radar system 112. Accordingly, the position information may include first position information for plane 191 and second position information for plane 192. LIS 113 may use information from radar system 112 to determine the velocity of each aircraft. The position and velocity information for each aircraft may be stored in database 114.

[0018] As further shown in FIG. 2, network function 102 may receive a message 202 (e.g., an access request message) transmitted by aircraft 191. In one embodiment, message 202 includes position information aircraft 191 (e.g., the message contains information specifying the current position of aircraft 191 or specifying a predicted position of aircraft 191). Message 202 may also contain velocity information for aircraft 191. In another embodiment, message 202 triggers network function to send to LIS 113 a request 203 for information for aircraft 191, which responds to the request by transmitting to network function 102 a response message 204 containing the requested information for aircraft 191, which information may contain position information indicating a current position of the aircraft and velocity information indicating the aircrafts velocity.

[0019] After obtaining the position information for aircraft 191, network function, in one embodiment, selects, from among a group of candidate TRxPs, at least one TRxP to serve aircraft 191. A variety of factors can go into the selection process. For example, network function 102 can simply select the TRxP(s) that is/re closest to aircraft 191. As another example, network function 102 can select the TRxP(s) that is/are closest to aircraft 191 and has/have a load below a threshold. As another example, network function 102 can select the TRxP(s) based on their capabilities, such as, the frequency bands in which the operate. For instance, the UEs on aircraft 191 may only be able to communicate using a certain frequency band, thus network function 102 will exclude from consideration any TRxP that is not capable of operating in that certain frequency band. For this example, assume that network function 102 has selected at least TRxP 105 (if network function has selected another TRxP in addition to TRxP 105, then the steps described below would also be performed for the other selected TRxP).

[0020] After selecting TRxP 105, network function 102 uses the position information indicating the position of aircraft 191 and position information indicating the position of TRxP 105 to obtain directional information (e.g., two angles: an azimuth angle 0 and an elevation angle <|)) indicating a direction from TRxP 105 to aircraft 191. And after obtaining the direction information, network function 102 triggers network node 104 to use TRxP 105 to transmit a signal in the indicated direction (e.g., transmit a synchronization signal that allows for any UE on the aircraft to attach and maintain connection to the network).

[0021] In some embodiments, network function 102 generates a precoding vector using the obtained directional information and network function 102 performs the above mentioned triggering step by triggering network node 104 to: i) precode the signal using the first precoding vector and ii) transmit the precoded signal using TRxP 105. Additionally, using the position information indicating the position of aircraft 191 and the position information indicating the position of TRxP 105, network function can calculate a distance from TRxP 105 to aircraft 191 and configure network node 104 to transmit the signal using a power level determined based on the calculated distance.

[0022] In one embodiment, TRxP 105 comprises an antenna array 150 comprising N antenna elements, radio ports, or subarrays, and the precoding vector comprises N weights, Wn for n=l to N, one for each one of the N antenna elements, radio ports, or subarrays.

[0023] In one embodiment, in the case of rank one or rank 2 transmission/reception, without spatial interference suppression, the DL/UL antenna precoder weight w_n for antenna element n, located at position (x_n, y_n, z_n) will is determined using a single (or dual) polarized linear phase front precoder according to:

where 0 and <|> are angular directions (relative to the z-axis, and rotation in x-y plane respectively) to the areal device and may be calculated using the position information indicating position of aircraft 191 and position information indicating position of TRxP 105. The coefficient X is the wavelength of the carrier signal. In a no scattering scenario, this precoder will be optimal for a rank 2 (orthogonal polarization precoding) transmission. [0024] In one embodiment, the position of aircraft 191 is provided to at least one neighboring cell, in which the position is considered in calculation of a null direction. The null direction is used by the network node to impose nulls in any transmit precoder calculated to limit the interference. As an example, consider FIG. 1, where network node 104 serves at least aircraft 191 and network node 106 serves aircraft 192. network node 106 is fed position of aircraft 191 and can thus decrease (null) interference transmitted in the direction of aircraft 191 (indicated by the X over direction 124). Interference mitigation is a key enabler for increasing capacity of a wireless system with multiple spatial data streams. Hence, interference mitigation to aircraft 191 may only be considered if aircraft 192 is scheduled for receiving data from network node 106.

[0025] In one embodiment the precoding weights for interference suppression is calculated as: w_n = w₀ - (1 - P)Sw_oe~^inS,

and 8 is the direction to be suppressed, where said direction information may obtained from LIS 113, and (i is a tuning factor determining the depth (magnitude) of the nulling.

[0026] Another option is to let the interference limiting precoder be defined as the eigenvector w that maximizes the generalized eigenvalue problem: Rw = Qw, where R is the covariance matrix dependent on the intended signal direction, determined by 9, <p, and Q is the covariance matrix for the signal direction to which interference suppression should be made, dependent on 6. This allows for easy extension of suppressing multiple directions as

a_nQ_n is the where Q_n is the covariance matrix for direction n, and a_t are scaling factors for each direction.

[0027] In an embodiment related to usage of more than one TRxP to provide coverage to a vehicle (e.g. a distributed MIMO embodiment), aerial position, speed and future estimated position, etc. can be shared between multiple network nodes to achieve coherent signal reception at the receiving point.

[0028] In one embodiment, radar system 112 and LIS 113 is integrated in one or more of network node 104 and network node 106. In one embodiment, the LIS 113 receives position information from a source other than radar system 112, such as, for example, from the aircrafts themselves which the aircraft may obtain through GPS, or similar. [0029] In one embodiment, LIS 113 fetches information from radar system 112 or other information source.

[0030] In one embodiment, aircraft 191 comprises network node (e.g., a base station) having a TRxP and the direction and beam refinement approach described herein may be considered for backhaul links.

[0031] While FIG. 1 illustrates the use of network function 102 with respect to aircraft (manned or unmanned), this disclosure is not so limited as network function 102 may also be used in maritime environments where the vehicles are water vehicles (boats, ships, etc.). Because water vehicles travel in the surface plane the space of possible angular directions 9,

as a function of the positions of the vehicle and TRxP may be reduced to the surface plane.

[0032] In one embodiment, aircraft 191 contacts network function 102 requesting network connection and reports its location. Network function then feeds the position or derived directional information to the closest network node (in the sense of expected radio signal strength) that supplies the connectivity for the area in which aircraft 191 is currently located. The position of the aircraft, position and orientation of TRxP antennas, as well as information about the corresponding antennas radiation pattern, carrier frequency, and transmit power can be utilized to predict the expected signal strength. In turn facilitating the selection of the closest TRxP in an expected radio signal sense.

[0033] In one embodiment, the predicted received signal strength is determined through geometrical relations such as the use of free space path loss (FSPL). With this, the fraction of received power P_r to the transmitted P_t can be expressed as:

where D_t and D_r are the antenna directivity (antenna gain), A the wavelength at transmitting frequency and d the distance between the transmitter and receiver.

[0034] In one embodiment, information about the velocity of the areal device is provided to network function 102 or network node 104 allowing for downlink signaling and uplink measurements to be shifted in frequency to compensate for the doppler shift in down link and uplink respectively. In one embodiment, network node 104 searches for Physical Random Access Channel (PRACH) preambles with the spatial profile and doppler shift that can be expected. [0035] In one embodiment, a handover procedure is initiated from one network node (e.g., 5G base station (gNB)) to another based on projected changes in signal strengths derived from the position and velocity vectors.

[0036] As an example for how to derive the directional information (i.e., elevation and azimuth angles) indicating the direction to the vehicle form the selected TRxP, consider the simplified 2-dimensional trigonometrical problem depicted in FIG. 3. Extensions to three dimensions, as well as taking earth curvature and terrain profile should be straight forward to anyone skilled in the art. The TRxP is located at (xi,yi), the radar system 112 is located at (x2,y2), and the aircraft is located at (x3,ys). It is assumed that the location of the radar and TRxP are known. A radar typically measures the distance, r2, and angle, 012, to the aircraft. Based on this, the location for the aircraft may be determined as: x₃ = x₂ + r₂cos(a₂) 73 = 72 + r₂sin(a₂)

[0037] Given the location of the aircraft together with the location of the TRxP, the distance and angle form theTRxP to the vehicle may be determined as:

[0038] FIG. 4 is a flowchart illustrating a process 400 performed by network function 102 for use in providing network coverage to a vehicle (e.g., aircraft 191 or aircraft 192), according to some embodiments. Process 400 may begin in step s402. Step s402 comprises network function 102 obtaining first position information indicating a first position of the vehicle (e.g., a current position of the vehicle and/or a predicted position of the vehicle at a future point in time). Step s404 comprises network function 102 using the first position information to obtain first directional information (e.g., one or two angles: an azimuth angle 0 and/or an elevation angle <|>) indicating a first direction to the vehicle from a first TRxP (e.g., TRxP 105), where the first TRxP is connected to or a component of a first network node. Step s406 comprises network function 102 triggering the first network node to use the first TRxP to transmit a signal in the indicated first direction. In some embodiments, the signal is a synchronization signal for enabling UEs in the vehicle to acquire time and frequency synchronization with a cell served by the network node and to detect the Physical layer Cell ID, PCI, of the cell. [0039] In some embodiments, process 400 further includes network function 102 generating a first precoding vector using the first directional information, wherein triggering the first network node to use the first TRxP to transmit the signal in the indicated first direction comprises triggering the first network node to: i) precode the signal using the first precoding vector and ii) transmit the precoded signal using the first TRxP.

[0040] In some embodiments, the network function is a component of the first network node. In some embodiments, the network function is a component of a server, the server is remote from the first network node.

[0041] In some embodiments, triggering the first network node to: i) precode the signal using the first precoding vector and ii) transmit the precoded signal using the first TRxP comprises: providing to the first network node the first precoding vector, or providing to the first network node the directional information to enable the first network node to generate the first precoding vector.

[0042] In some embodiments, the first TRxP comprises an antenna array comprising N antenna elements, radio ports, or subarrays, an the first precoding vector comprises N weights, Wn for n=l to N, one for each one of the N antenna elements, radio ports, or subarrays. In some embodiments, the first network node transmits the signal using a carrier frequency the first directional information comprises an azimuth angle value 0 and an elevation angle value cp, and generating the first precoding vector comprises calculating: w_n =

X is the wavelength of the carrier frequency, x_n is a first coordinate of the n-th antenna element of the antenna array, y_n is a second coordinate of the n-th antenna element of the antenna array, and z_n is a third coordinate of the n-th antenna element of the antenna array.

[0043] In some embodiments, process 400 further includes network function 102 receiving a message transmitted by the vehicle or a location information server, wherein the network function obtains the first position information in response to receiving the message.

[0044] In some embodiments, the vehicle is an aircraft or water vehicle, an obtaining the first position information comprises the network function transmitting to a location information server a request message requesting the first position information. [0045] In some embodiments, obtaining the first position information comprises receiving a message transmitted by the vehicle, wherein the message comprises the first position information.

[0046] In some embodiments, process 400 further includes network function 102 using the first position information to obtain second directional information indicating a second direction to the vehicle from a second TRxP of a second network node; and network function 102 using the second directional information to limit interference caused by transmissions from the second TRxP of the second network node. In some embodiments, using the second directional information to limit interference caused by transmissions from the second TRxP of the second network node comprises: generating a second precoding vector using the second directional information, and transmitting to the second network node a message comprising the second precoding vector.

[0047] In some embodiments process 400 further includes network function 102 using the first position information to obtain second directional information indicating a second direction to the vehicle from a second TRxP of a second network node; and network function 102 triggering the second network node to use the second TRxP to transmit a signal in the second direction indicated by the second directional information.

[0048] In some embodiments the location information server obtains the first position information from a radar system for tracking flying objects (e.g., radar system 112).

[0049] In some embodiments process 400 further includes obtaining velocity information indicating a velocity of the vehicle; and shifting in frequency uplink and/or downlink measurements to compensate for Doppler shift.

[0050] In some embodiments process 400 further includes, after obtaining the first position information, obtaining second position information indicating a second position of the vehicle (current position or predicted position); using the second position information to obtain second directional information indicating a second direction to the vehicle from the first TRxP; and using the first TRxP to transmit the signal in the indicated second direction.

[0051] In some embodiments process 400 further includes, after obtaining the first position information and before using the first position information to obtain first directional information, selecting, based on one or more criteria, at least the first TRxP from a set of available TRxPs. [0052] FIG. 5 is a block diagram of a network node 504, according to some embodiments, for use in implementing network function 102. As shown in FIG. 5, network node 504 may comprise: processing circuitry (PC) 502, which may include one or more processors (P) 555 (e.g., a general purpose microprocessor and/or one or more other processors, such as an application specific integrated circuit (ASIC), field-programmable gate arrays (FPGAs), and the like), which processors may be co-located in a single housing or in a single data center or may be geographically distributed (i.e., network node 504 may be a distributed computing apparatus); at least one network interface 548 comprising a transmitter (Tx) 545 and a receiver (Rx) 547 for enabling network node 504 to transmit data to and receive data from other nodes connected to a network 110 (e.g., an Internet Protocol (IP) network) to which network interface 548 is connected (directly or indirectly) (e.g., network interface 548 may be wirelessly connected to the network 110, in which case network interface 548 is connected to an antenna arrangement); and a storage unit (a.k.a., “data storage system”) 508, which may include one or more non-volatile storage devices and/or one or more volatile storage devices. In an alternative embodiment the network interface 548 may be connected to the network 110 over a wired connection, for example over an optical fiber or a copper cable. In embodiments where PC 502 includes a programmable processor, a computer program product (CPP) 541 may be provided. CPP 541 includes a computer readable medium (CRM) 542 storing a computer program (CP) 543 comprising computer readable instructions (CRI) 544. CRM 542 may be a non-transitory computer readable medium, such as, magnetic media (e.g., a hard disk), optical media, memory devices (e.g., random access memory, flash memory), and the like. In some embodiments, the CRI 544 of computer program 543 is configured such that when executed by PC 502, the CRI causes network node 504 to perform steps of the methods described herein (e.g., steps described herein with reference to one or more of the flow charts). In other embodiments, network node 504 may be configured to perform steps of the methods described herein without the need for code. That is, for example, PC 502 may consist merely of one or more ASICs. Hence, the features of the embodiments described herein may be implemented in hardware and/or software.

[0053] While various embodiments are described herein, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of this disclosure should not be limited by any of the above-described exemplary embodiments. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.

[0054] Additionally, while the processes described above and illustrated in the drawings are shown as a sequence of steps, this was done solely for the sake of illustration. Accordingly, it is contemplated that some steps may be added, some steps may be omitted, the order of the steps may be re-arranged, and some steps may be performed in parallel.

Claims

1. A method (400) for use in providing network coverage to a vehicle (191, 192), the method comprising: obtaining (s402) first position information indicating a first position of the vehicle; using (s404) the first position information to obtain first directional information indicating a first direction to the vehicle from a first transmitting and receiving point, TRxP (105), of or connected to a first network node (104); and triggering (s406) the first network node to use the first TRxP to transmit a signal in the indicated first direction.

2. The method of claim 1, further comprising generating a first precoding vector using the first directional information, wherein triggering the first network node to use the first TRxP to transmit the signal in the indicated first direction comprises triggering the first network node to: i) precode the signal using the first precoding vector and ii) transmit the precoded signal using the first TRxP.

3. The method of claim 1 or 2, wherein the method is performed by a network function (102) that is a component of the first network node.

4. The method of claim 1 or 2, wherein the method is performed by a network function (102), the network function is a component of a network node (504), and the network node (504) is remote from the first network node.

5. The method of any one of claims 2-4, wherein triggering the first network node to: i) precode the signal using the first precoding vector and ii) transmit the precoded signal using the first TRxP comprises: providing to the network node the first precoding vector, or providing to the network node the directional information to enable the network node to generate the first precoding vector.

6. The method of any one of claims 2-5, wherein the first TRxP comprises an antenna array comprising N antenna elements, radio ports, or subarrays, and the first precoding vector comprises N weights, w_n for n=l to N, one for each one of the N antenna elements, radio ports, or subarrays.

7. The method of claim 6, wherein the first network node transmits the signal using a carrier frequency, the first directional information comprises an azimuth angle value 0 and an elevation angle value cp, and generating the first precoding vector comprises calculating:

Z is the wavelength of the carrier frequency, x_n is a first coordinate of the nth antenna element of the antenna array, and y_n is a second coordinate of the nth antenna element of the antenna array.

8. The method of any one of claims 1-7, further comprising a network function (102) receiving a message transmitted by the vehicle or a location information server (113), wherein the network function obtains the first position information in response to receiving the message.

9. The method of any one of claims 1-8, wherein the vehicle is an aircraft or water vehicle, and obtaining the first position information comprises transmitting to a location information server a request message requesting the first position information.

10. The method of any one of claims 1-7, wherein obtaining the first position information comprises receiving a message transmitted by the vehicle, wherein the message comprises the first position information.

11. The method of any one of claims 1-10, wherein the signal is a synchronization signal for enabling user equipments, UEs, in the vehicle to acquire time and frequency synchronization with a cell served by the network node and to detect the Physical layer Cell ID, PCI, of the cell.

12. The method of any one of claims 1-11, further comprising: 15 using the first position information to obtain second directional information indicating a second direction to the vehicle from a second TRxP of a second network node; and using the second directional information to limit interference caused by transmissions from the second TRxP of the second network node.

13. The method of claim 12, wherein using the second directional information to limit interference caused by transmissions from the second TRxP of the second network node comprises: generating a second precoding vector using the second directional information, and transmitting to the second network node a message comprising the second precoding vector.

14. The method of any one of claims 1-11, further comprising: using the first position information to obtain second directional information indicating a second direction to the vehicle from a second TRxP of a second network node; and triggering the second network node to use the second TRxP to transmit a signal in the second direction indicated by the second directional information.

15. The method of claim 9, wherein the location information server obtains the first position information from a radar system (112) for tracking flying objects.

16. The method of any one of claims 1-15, further comprising: obtaining velocity information indicating a velocity of the vehicle; and shifting in frequency uplink and/or downlink measurements to compensate for Doppler shift.

17. The method of any one of claims 1-16, further comprising: after obtaining the first position information, obtaining second position information indicating a second position of the vehicle (current position or predicted position); using the second position information to obtain second directional information indicating a second direction to the vehicle from the first TRxP; and using the first TRxP to transmit the signal in the indicated second direction.

18. The method of any one of claims 1-17, further comprising: 16 after obtaining the first position information and before using the first position information to obtain first directional information, selecting, based on one or more criteria, at least the first TRxP from a set of available TRxPs.

19. A computer program (543) comprising instructions (544) which when executed by processing circuitry (502) of an network node (504) causes the network node (504) to perform the method of any one of claims 1-18.

20. A carrier containing the computer program of claim 19, wherein the carrier is one of an electronic signal, an optical signal, a radio signal, and a computer readable storage medium (542).

21. A network node (504) for use in providing network coverage to a vehicle (191, 192), the network node being configured to: obtain (s402) first position information indicating a first position of the vehicle; use (s404) the first position information to obtain first directional information indicating a first direction to the vehicle from a first transmitting and receiving point, TRxP (105); and trigger (s406) the first TRxP to transmit a signal in the indicated first direction.

22. The network node of claim 21, wherein the network node is further configured to perform the method of any one of claims 2-18.

23. The network node of claim 21 or 22, wherein the network node is configured to trigger the first TRxP to transmit the signal in the indicated first direction by triggering a second network node to trigger the first TRxP to transmit the signal in the indicated direction.

24. A network node (105), the network node (105) comprising: processing circuitry (502); and a memory (542), the memory containing instructions (544) executable by the processing circuitry, wherein the network node is configured to: obtain (s402) first position information indicating a first position of the vehicle; 17 use (s404) the first position information to obtain first directional information indicating a first direction to the vehicle from a first transmitting and receiving point, TRxP (105), of or connected to a first network node (104); and trigger (s406) the first TRxP to transmit a signal in the indicated first direction.