Methods, control units and calculating units for determining channel information matrix of wireless communication channels between a user equipment and multiple antennas arranged on a vehicle

Abstract

A method performed by a control unit (180) arranged on a vehicle (130), for determining a channel information matrix of wireless communication channels between a User Equipment, UE (140) and multiple antennas (142, 144) arranged on the vehicle (130), the control unit (180) being arranged to make measurements of phase and amplitude of reference signals, received from the UE (140) by the multiple antennas (142, 144), the method comprises: making (204) a first measurement at a first measuring position (162, 166, 170); making (206) a second measurement at a second measuring position (164, 168, 172), wherein the first and second measurement positions (162, 166, 170, 164, 168, 172) spatially overlap in at least one antenna position (A1 ).

Description

METHODS, CONTROL UNITS AND CALCULATING UNITS FOR DETERMINING CHANNEL INFORMATION MATRIX OF WIRELESS COMMUNICATION CHANNELS BETWEEN A USER EQUIPMENT AND MULTIPLE ANTENNAS ARRANGED ON A VEHICLE TECHNICAL FIELD

[0001] The present disclosure relates generally to methods, control units and calculating units for determining channel information matrix of wireless communication channels between a user equipment and multiple antennas arranged on a vehicle. The present disclosure also relates to computer programs and carriers corresponding to the methods. BACKGROUND

[0002] Positioning has been a hot topic for 5G, and it is expected that positioning will remain important for 6G. One important aspect of positioning is the use of large antenna arrays at the base station, allowing for direction of arrival (DoA) estimation and / or time of arrival (ToA) estimation, so as to provide positioning of a single terminal, e.g., User Equipment (UE).

[0003] There are several algorithms for estimating DoA by using large antenna arrays, which comprises multiple antennas, e.g., Multiple Signal Classification (MUSIC) and Estimation of Signal Parameters via Rotational Invariant Techniques (ESPRIT), etc.

[0004] Generally speaking, the larger the base station antenna array is, i.e., the more antennas in the antenna array, the better the DoA estimation becomes. Furthermore, if the distance between the base station and UE becomes closer, the positioning becomes more accurate.

[0005] In some scenario, e.g., an avalanche situation involving a group of skiers, accurate positioning within short time is crucial to find and rescue the skiers buried in the snow. Many skiers, but not all, are therefore wearing avalanche transceivers when skiing. However, for a skier not wearing an avalanche transceiver, it is verylikely that the skier is equipped with a cell phone, i.e., a UE. This enables positioning utilizing the UE and base station nearby.

[0006] As mentioned above, one core aspect for accurate positioning of the UE is a large antenna array at the base station. However, large antenna arrays, and dense base station deployments, are most used today in dense urban areas to improve network capacity. It is unlikely that such systems will be deployed in more remote rural areas, e.g., a mountain which comprises a ski resort. Furthermore, even if base stations are deployed, the positioning resolutions may not be good enough due to insufficient antenna number in the antenna array in the base station. Inaccurate positioning of the UE results inaccurate rescue, which is dangerous to the skiers blocked by the snow.

[0007] Therefore, there is a need to provide a solution, so that an accurate and high-efficient positioning of a UE can be performed, even though the base station does not have a large antenna array. SUMMARY

[0008] It is an object of the invention to address at least some of the problems and issues outlined above. It is an object of embodiments of the invention to provide an accurate positioning of a UE without having a large antenna array in a base station. It is possible to achieve one or more of these objects and possibly others by using methods, control units and calculating units as defined in the attached independent claims.

[0009] According to an embodiment, a method performed by a control unit arranged on a vehicle, for determining a channel information matrix of wireless communication channels between a User Equipment, UE and multiple antennas arranged on the vehicle is disclosed, the control unit being arranged to make measurements of phase and amplitude of reference signals, received from the UE by the multiple antennas, the method comprises: making a first measurement at a first measuring position, making a second measurement at a second measuringposition, wherein the first and second measurement positions spatially overlap in at least one antenna position.

[0010] According to another aspect, a method performed by a calculating unit for determining a channel information matrix of wireless communication channels between a User Equipment, UE and multiple antennas arranged on a vehicle, the vehicle being arranged to make measurements of phase and amplitude of reference signals, received from the UE by the multiple antennas, the method comprises: obtaining a first and a second measurement from the vehicle; determining the channel information matrix based on the obtained first and second measurements, wherein the first and second measurements being made in a first and second measuring positions, the first and second measuring positions spatially overlap in an antenna position, wherein the determining of the channel information matrix comprises eliminating a phase error in channel information of the channel information matrix based on the first and second measurements.

[0011] According to another embodiment, a control unit arranged on a vehicle is disclosed. The control unit is operative for determining a channel information matrix of wireless communication channels between a User Equipment, UE and multiple antennas arranged on the vehicle, the control unit comprises a processing circuitry and a memory, the memory containing instructions executable by the processing circuitry, the control unit being arranged to make measurements of phase and amplitude of reference signals, received from the UE by the multiple antennas, whereby the control unit is operative for: making a first measurement at a first measuring position; making a second measurement at a second measuring position, wherein the first and second measurement positions spatially overlap in at least one antenna position.

[0012] According to another embodiment, a calculating unit for determining a channel information matrix of wireless communication channels between a User Equipment, UE and multiple antennas arranged on a vehicle is disclosed. The calculating unit comprises a processing circuitry and a memory, the memory containing instructions executable by the processing circuitry, the vehicle being arranged to make measurements of phase and amplitude of reference signals,received from the UE by the multiple antennas, whereby the calculating unit is operative for: a first and a second measurement from the vehicle; determining the channel information matrix based on the obtained first and second measurements, wherein the first and second measurements being made in a first and second measuring positions, the first and second measuring positions spatially overlap in an antenna position, wherein the determining of the channel information matrix comprises eliminating a phase error in channel information of the channel information matrix based on the first and second measurements.

[0013] According to other aspects, computer programs and carriers are also provided, the details of which will be described in the claims and the detailed description.

[0014] Further possible features and benefits of this solution will become apparent from the detailed description below. BRIEF DESCRIPTION OF DRAWINGS

[0015] The solution will now be described in more detail by means of exemplary embodiments and with reference to the accompanying drawings, in which:

[0016] Fig. 1 is a schematic diagram illustrating a system layout in which the embodiments of the present invention may be used.

[0017] Fig. 2 is a schematic block diagram illustrating a vehicle, according to possible embodiments.

[0018] Fig.3 is a flow chart of the method performed by a control unit arranged on the vehicle, according to possible embodiments.

[0019] Fig. 4 is a flow chart of the method performed by a calculating unit, according to possible embodiments.

[0020] Fig. 5 is a schematic diagram illustrating relationship between antenna positions and time, according to possible embodiments.

[0021] Fig.6, fig.7 and fig.8 show examples of vehicle movements, according to possible embodiments.

[0022] Fig. 9a and 9b are schematic block diagrams illustrating positioning arrangements, according to possible embodiments.

[0023] Fig.10 and fig.11 are schematic block diagrams illustrating the control unit and the calculating unit in detail, according to possible embodiments. DETAILED DESCRIPTION

[0024] Fig. 1 is a schematic diagram illustrating a system layout for positioning according to the present invention. A UE 140 is the UE which needs to be positioned. The UE 140 can be, for example, a mobile phone, smart phone or a tablet / laptop with wireless connectivity.

[0025] A vehicle 130 is arranged for positioning the UE 140. Two antennas 142, 144 are arranged on the vehicle 130 and the two antennas 142, 144 are operative for wirelessly communication with the UE 140, i.e., transmit / receive wireless signals to / from the UE 140. Please note that two antennas 142, 144 are shown in fig. 1, however the number of antennas arranged on the vehicle 130 can be another integer, as long as it is equal to or larger than two.

[0026] The UE 140 and the antennas 142, 144 can wirelessly communicate with any kind of wireless communication network. Example of such wireless communication networks are Global System for Mobile communication (GSM), Enhanced Data Rates for GSM Evolution (EDGE), Universal Mobile Telecommunications System (UMTS), Code Division Multiple Access 2000 (CDMA 2000), Long Term Evolution (LTE) Frequency Division Duplex (FDD) and Time Division Duplex (TDD), LTE Advanced, Wireless Local Area Networks (WLAN), Worldwide Interoperability for Microwave Access (WiMAX), WiMAX Advanced, as well as 5G wireless communication networks based on technology such as New Radio (NR), or even 6G.

[0027] The vehicle 130 can be any kind of vehicle, e.g., unmanned aerial vehicle (UAV) as shown in fig.1. The UAV is an aircraft without any human pilot on board.Any kind of UAV is applicable in this invention, as long as it is equipped with at least two antennas and can perform radio signal phase / amplitude measurement. For example, the UAV can be a helicopter, a search and rescue UAV or a parcel delivery UAV. The vehicle 130 can also be other kind of land vehicle or vessel, e.g., truck, car, boat, etc.

[0028] The vehicle 130 moves along a trajectory and receiving wireless signals, e.g., reference signals, from the UE 140 at different measuring positions 162, 164. The trajectory is known to the vehicle 130, e.g., a predefined trajectory. As shown in fig.2, a control unit 180 is arranged on the vehicle 130 and is operative for making measurements of phase and amplitude of the reference signals received by the antennas 142, 144 from the UE 140.

[0029] The basic idea of the invention is that the control unit 180 make measurements at different measuring positions 162, 164, wherein the measuring positions 162, 164 are overlapped at one antenna position A1, i.e., the position of the antenna 144 in the measuring position 162 is the same as the position of the antenna 142 in the measuring position 164. Therefore, at the antenna position A1, the reference signals are measured twice at two different time points. Meanwhile, the reference signals received by the antenna 142 at the position A2 and the reference signals received by the antenna 144 at the position A3 are also measured. The measurements of phase and amplitude of reference signals are sent to a calculating unit 190. The calculating unit 190 can be arranged on the vehicle 130, or arranged on an external device, e.g., a server, a cloud device, etc. The calculating unit 190 determines a channel information matrix based on the measurements, and the element number of the channel information matrix is equal to the number of unique spatial antenna positions, i.e., three in the scenario shown in fig. 1. Each channel information element in the channel information matrix relates to a wireless channel between the UE 140 and an antenna position, i.e., each of the three channel information element in the channel information matrix respectively relates to the wireless channel between the UE 140 and A1, the wireless channel between the UE 140 and A2, the wireless channel between UE 140 and A3.

[0030] When the channel information matrix is determined, it can be used to perform positioning algorithm. The channel information matrix works as a virtual antenna array, as if there is an antenna array with antennas elements in positions A1, A2 and A3. Therefore, DoA estimation can be performed based on the channel information matrix, the angle α can be determined precisely, even though there are only two physical antennas 142, 144 on the vehicle 130. Furthermore, ToA estimation can also be performed, and the distance d can be determined.

[0031] Fig.3 schematically shows a flow chart of the method performed by the control unit 180 arranged on the vehicle 130. A method performed by a control unit 180 arranged on a vehicle 130, for determining a channel information matrix of wireless communication channels between a User Equipment, UE 140 and multiple antennas 142, 144 arranged on the vehicle 130, the control unit 180 being arranged to make measurements of phase and amplitude of reference signals, received from the UE 140 by the multiple antennas 142, 144, the method comprises: making 204 a first measurement at a first measuring position 162, 166, 170; making 206 a second measurement at a second measuring position 164, 168, 172, wherein the first and second measurement positions 162, 164 spatially overlap in at least one antenna position A1.

[0032] Referring to fig.2, a vehicle 130 is utilized in this method. One control unit 180 and multiple antennas 142, 144 are arranged on the vehicle 130. In the example shown in fig. 2, two antennas 142, 144 are arranged on the vehicle 130. The antennas 142, 144 is operative for receiving wireless reference signals from the UE 140. The reference signals from the UE 140 can be e.g., sounding reference signal (SRS). The control unit 180 is operative for making measurements of phase and amplitude of the reference signals received by the antennas 142, 144.

[0033] In the step 204, the control unit 180 makes a first measurement at a first measuring position 162, 166, 170. Referring to the embodiment shown in fig.5 and fig.6, in the time t1, the vehicle 130 is positioned in the first measuring position 162. In this measuring position 162, the antenna 142 is located in the antenna position A2 and the antenna 144 is located in the antenna position A1. Therefore, the measuring position 162 is a combination of the antenna positions A2 and A1. Inother words, in the time t1, the control unit 180 makes the first measurement of the phase and amplitude of the reference signals received by the antenna 142 at the antenna position A2, and the phase and amplitude of the reference signals received by the antenna 144 at the antenna position A1.

[0034] Similarly, in the embodiment shown in fig.7, the control unit 180 makes the first measurement in the first measuring position 166. The first measuring position 166 is a combination of the antenna position A1 and the antenna position A2. The first measurement comprises the phase / amplitude of the reference signals received by the antenna 142 at the antenna position A1 and the phase / amplitude of the reference signals received by the antenna 144 at the antenna position A2. In the embodiment shown in fig.8, the control unit 180 makes the first measurement in the first measuring position 170. The first measuring position 170 is a combination of the antenna position A2 and the antenna position A1. The first measurement comprises the phase / amplitude of the reference signals received by the antenna 142 at the antenna position A2 and the phase / amplitude of the reference signals received by the antenna 144 at the antenna position A1.

[0035] In the step 206, the control unit 180 makes a second measurement at a second measuring position 164, 168, 172, wherein the first and second measurement positions 162, 166, 170, 164, 168, 172 spatially overlap in at least one antenna position A1.

[0036] In the embodiment shown in fig.5 and 6, the vehicle 130 moves along a trajectory 160, so that in the time t2, the vehicle 130 is located in a second measuring position 164. In the second measuring position 164, the antenna 142 is located in the antenna position A1 and the antenna 144 is located in the antenna position A3. Therefore, the measuring position 164 is a combination of the antenna positions A1 and A3. In the second measuring position 164, the control unit 180 makes a second measurement, the second measurement comprises the measurement of the phase / amplitude of the reference signal received by the antenna 142 at the antenna position A1 and the phase / amplitude of the reference signal received by the antenna 144 at the antenna position A3. The first and second measuring positions 162 and 164 are spatially overlapped in the antenna positionA1, i.e., the reference signal received at the antenna position A1 is received and measured twice: in the time t1, the reference signal is received by the antenna 144 at the antenna position A1, then measured by the control unit 180; in the time t2, the reference signal is received by the antenna 142 at the antenna position A1, then measured by the control unit 180. Besides, in the time t1, the reference signals received at the antenna position A2 by the antenna 142 is also measured. In the time t2, the reference signals received at the antenna position A3 by the antenna 144 is also measured.

[0037] In the embodiment shown in fig.7, after the first measurement in the first measuring position 166, the vehicle 130 moves along the trajectory 160, so that the vehicle 130 is located in the second measuring position 168. The second measuring position 168 is a combination of the antenna position A1 and the antenna position A3, so that the second measuring position 168 is overlapped with the first measuring position 166 in the antenna position A1. The control unit 180 makes the second measurement in the second measuring position 168, so that the second measurement comprises the measurement of phase / amplitude of the reference signal received by the antenna 142 at the antenna position A1 and the measurement of phase / amplitude of the reference signal received by the antenna 144 at the antenna position A3. The reference signals received at the antenna position A1 is received and measured twice: first time received by the antenna 142 in the antenna position A1 in the first measuring position 166 and measured, second time received by the antenna 142 in the antenna position A1 in the second measuring position 168.

[0038] In the embodiment shown in the fig.8, after the first measurement in the first measuring position 170, the vehicle 130 moves along the trajectory 160, so that the vehicle 130 is located in the second measuring position 172. The second measuring position 172 is a combination of the antenna position A1 and the antenna position A3, so that the second measuring position 172 is spatially overlapped with the first measuring position 170 in the antenna position A1. The control unit 180 makes the second measurement in the second measuring position 172, so that the second measurement comprises the measurement of phase / amplitude of thereference signal received by the antenna 144 at the antenna position A1 and the measurement of phase / amplitude of the reference signal received by the antenna 142 at the antenna position A3. The reference signals received at the antenna position A1 is received and measured twice: first time received by the antenna 144 in the antenna position A1 in the first measuring position 170 and measured, second time received by the antenna 144 in the antenna position A1 in the second measuring position 172.

[0039] By such an embodiment, the first and second measurements of the reference signals are obtained. The measurements are used for determining channel information matrix in the calculating unit 190. Since the first and second measurement positions spatially overlap in the antenna position A1, a phase error due to UE non-coherency can be estimated and eliminated in the channel information matrix, based on the two times measurements in the antenna position A1. The determination of channel information matrix by the calculating unit 190 will be discussed in the text below.

[0040] According to another embodiment, fig.4 schematically shows a flow chart of a method performed by a calculating unit 190 for determining a channel information matrix of wireless communication channels between a User Equipment, UE 140 and multiple antennas 142, 144 arranged on a vehicle 130, the vehicle 130 being arranged to make measurements of phase and amplitude of reference signals, received from the UE 140 by the multiple antennas 142, 144, the method comprises: obtaining 304 a first and a second measurement from the vehicle 130; determining 306 the channel information matrix based on the obtained first and second measurements, wherein the first and second measurements being made in a first and second measuring positions 162, 164, the first and second measuring positions 162, 164 spatially overlap in an antenna position A1, wherein the determining 306 of the channel information matrix comprises eliminating a phase error in channel information of the channel information matrix based on the first and second measurements.

[0041] In this embodiment, the method performed by the calculating unit 190 is defined. The calculating unit 190 can be arranged on the vehicle 130, or arrangedon other network entity, e.g., a server, a cloud device, etc. The calculating unit 190 obtains the first and second measurements from the control unit 180 of the vehicle 130. The first measurement and the second measurement are made by the control unit 180 of the vehicle 130 according to the methods defined above.

[0042] In the step 306, the calculating unit 190 defines a channel information matrix based on the first and second measurements. The number of elements of the channel information matrix is equal to the number of antenna positions, i.e., in the embodiments shown in figs.6-8, the number of elements of the channel information matrix is equal to the number of antenna positions A1, A2 and A3, so that there are 3 elements in the determined channel information matrix. The three elements of the channel information matrix respectively relate to the wireless channel between the UE 140 and the antenna position A1, the wireless channel between the UE 140 and the antenna position A2, the wireless channel between the UE 140 and the antenna position A3. When there are more antenna positions, the number of elements becomes more.

[0043] The determining 306 of the channel information matrix comprises eliminating a phase error in channel information of the channel information matrix based on the first and second measurements.

[0044] A standard 3GPP based UE 140 is typically not phase coherent between two separate reference signal transmissions. Thus, measuring the same wireless channel ℎ, at the exact same location, at two separate time instances, they will differwith an unknown phase rotation ^ as ℎ^(^^) = ℎ^(^ ^^^)^ , where ℎ^ denotes that it is ameasurement of ℎ. This phenomenon is UE non-coherency.

[0045] However, using the measurement process described in this embodiment, the overlapped measurements allow for estimating the phase error in the channel information due to the UE non-coherency.

[0046] We assume that the vehicle 130 movement between two measuring positions is exactly the same as the antenna separation.

[0047] Denoting the channel information measured by the vehicle 130 at time ^^ at vehicle location ^^ as ^^^^(^^) = ^^^(^^)^^^^^ + ^(^), where ^^^(^^) =^ is the true channel, ^(^) is noise, and w ( ))here ℎ^^^(^^) , ℎ^^^ ^^ is thechannel at antenna 142 and 144 respectively. We know that if the positions of the transmitter and receiver are essentially unchanged, the channel at antenna 144 at vehicle position P1 should be the same as the channel observed at antenna 142 at vehicle)

[0048] Thus, the unknown phase rotation between time ^^and ^^can be estimated as ^^^^ = ∠ ℎ^^^^(^^)ℎ^^^^(^^)∗. By phase compensating the measurement at vehicle position P2 given the phase offset ^^^^ as ^^^^(^^) = ^^^^(^^)^^^^^^, we obtain a channel information matrix which can be used to create a virtual antenna array with 3 elements: ) ))

[0049] This process is then repeated for all vehicle positions ^^ ∈ {^^, ^^, … , ^^^^}allowing creation of channel information matrix as if sampled form an antenna of ^^^^ + 1 elements:

[0050] It should be readily understood that the process above easily extends to arbitrary measurement antenna array sizes with more than 2 elements, and arbitrary measurement overlaps Ω = 1,2, … ^ − 1, where N is the number of antennas usedfor measurement.

[0051] By determining the channel information matrix based on the measurements, the channel information matrix is used as a virtual antenna array with three virtual antennas at the antenna positions A1, A2 and A3. The phase error due to UE non-coherency is estimated based on the two measurements at oneantenna position A1. Then the estimated phase error is eliminated in the channel information matrix so that the channel information matrix is more accurate. The virtual antenna array is larger than the antenna array on the vehicle 130, which only comprises two physical antennas 142, 144. In this way, the limit of the number of the physical antennas is broken, and a larger virtual antenna array is used for positioning the UE 140. The positioning of the UE 140 is more efficient and accurate.

[0052] According to another embodiment, the method further comprises: determining 308 a position of the UE 140 based on the determined channel information matrix.

[0053] By using the determined channel information matrix ^^^^, the position of the UE 140 can be determined.

[0054] According to another embodiment, the determining 308 of the position of the UE 140 comprises determining a Direction-of-Arrival, DoA based on the determined channel information matrix.

[0055] According to another embodiment, the referring to fig. 9a and 9b, the determining 308 of the position of the UE 140 further comprises determining the position of the UE 140 based on the DoA determination performed by the calculating unit 190 and a DoA determination performed by another calculating unit 200, wherein the another calculating unit 200 is operative for performing the method as defined above, or the determining 308 of the position of the UE 140 further comprise determining the position of the UE 140 based on at least two DoA determinations performed by the calculating unit 190 in at least two times.

[0056] In this embodiment, referring to fig. 9a, another vehicle 210 which is spatially separated from the vehicle 130 can also be used. For the vehicle 210, a calculating unit 200 obtains the measurements made by the vehicle 210, determines a channel information matrix and performs DoA based on the determined channel information matrix. The DoA performed by the calculating unit 200 is used together with the DoA performed by the calculating unit 190, so that the position of the UE140 is accurately determined. Similar as the calculating unit 190, the calculating unit 200 can be equipped on the vehicle 210, or equipped on another network entity.

[0057] Alternatively, referring to fig.9b, one vehicle can be used to perform the DoA determination for at least two times in at least two times. As an example, the vehicle starts at a position X1 in a time t1, then moves along the X1 trajectory for measurements. A DoA determination is performed by the method defined above, so that a coarse position Y1 of the UE is determined. Then the vehicle moves to a location, X2, which is suitable for location refinement measurements. Another DoA determination is performed by the method defined above, so that a fine position Y2 of the UE is determined. This process can of course be repeated for as many times as needed, until an accurate location of the UE is determined.

[0058] According to another embodiment, wherein the determining 306 of the channel information matrix further comprises determining multiple channel information in the antenna position A1 and averaging the multiple channel information.

[0059] By determining multiple channel information in the antenna position A1 and averaging the multiple channel information, the impact of noise can be eliminated and the channel information matrix is more accurate. There is also no limitation in creating a linear or plane virtual antenna array. The virtual antenna array may as well be curved as long as the direction difference between the overlapping antennas from two measurements are small enough to not significantly affect the directional properties of the antennas.

[0060] The solution described in this invention relies on that the wireless channel ℎ at the two separate time instances does indeed correspond to exactly the same locations of the transmitter and receiver, and that the environment is essentially static. “Essentially” means that the direct path used in the present invention should not be affected by any movement leading to time-dynamic blockage. The similarity of the vehicle antenna locations is usually rather well understood and controlled but it is possible that the UE 140 is not static, e.g. if the user of the UE 140 is struggling against the snow or moving during the measurement procedure. Such movementmay have a large impact on the phase of the channel between the two time instants which might be mistaken for a different direction to the UE 140. It is known that the phase variation in the wireless channel occurs at a rate of movement in relation to the carrier wavelength. For a transmission at 3GHz where the wavelength is 10 cm, the phase can vary rapidly even for a movement of only one or a few cm.

[0061] To mitigate errors introduced by UE 140 movement, the following methods can be used.

[0062] 1. Using a lower frequency for positioning. 3GPP-based networks and devices can communicate using a range of different frequency bands, and the lowest of the bands available should be selected for positioning to minimize the phase variation in the channel from a small movement.

[0063] 2. Configuring the speed of the vehicle 130 when moving along the trajectory and the frequency of the SRS transmissions from the UE 140, so that the time difference between the two separate time instances is minimized. The New Radio (NR) standard has a large flexibility for how often SRS transmissions may be configured where the most frequent SRS transmissions may be in the ms or even sub-ms periodicity. During such small time shifts the impact of a more slowly moving UE 140 can be minimal. However, the vehicle antenna 142 needs to move from A2 to A1 in the same time period, see fig.5. Hence, the SRS transmission periodicity and the vehicle movement pattern needs to be jointly configured. In essence, the solution is to use a very high vehicle speed, much higher than the expected speed of movement of UE 140.

[0064] 3. Instructing the user of the UE 140 through an app or similar to stay stationary while the measurement is ongoing.

[0065] 4. Letting the app report whether the UE 140 is stationary or moving, e.g., based on gyro sensors that are present in most smartphones, and perform the measurements opportunistically while the UE 140 is stationary.

[0066] According to another embodiment, a control unit 180 arranged on a vehicle 130 is disclosed. The control unit 180 is operative for determining a channelinformation matrix of wireless communication channels between a User Equipment, UE 140 and multiple antennas 142, 144 arranged on the vehicle 130, the control unit 180 comprises a processing circuitry 603 and a memory 604, the memory 604 containing instructions executable by the processing circuitry 603, the control unit 180 being arranged to make measurements of phase and amplitude of reference signals, received from the UE 140 by the multiple antennas 142, 144, whereby the control unit 180 is operative for: making a first measurement at a first measuring position 162, 166, 170; making a second measurement at a second measuring position 164, 168, 172, wherein the first and second measurement positions 162, 166, 170, 164, 168, 172 spatially overlap in at least one antenna position A1.

[0067] According to another embodiment, the vehicle 130 is an ariel vehicle, a land vehicle or a vessel.

[0068] According to another embodiment, a calculating unit 190 for determining a channel information matrix of wireless communication channels between a User Equipment, UE 140 and multiple antennas 142, 144 arranged on a vehicle 130 is disclosed. The calculating unit 190 comprises a processing circuitry 703 and a memory 704, the memory 704 containing instructions executable by the processing circuitry 703, the vehicle 130 being arranged to make measurements of phase and amplitude of reference signals, received from the UE 140 by the multiple antennas 142, 144, whereby the calculating unit 190 is operative for: obtaining a first and a second measurement from the vehicle 130; determining the channel information matrix based on the obtained first and second measurements, wherein the first and second measurements being made in a first and second measuring positions 162, 164, the first and second measuring positions 162, 164 spatially overlap in an antenna position A1, wherein the determining of the channel information matrix comprises eliminating a phase error in channel information of the channel information matrix based on the first and second measurements.

[0069] According to another embodiment, the calculating unit 190 is further operative for: determining a position of the UE 140 based on the determined channel information matrix.

[0070] According to another embodiment, the determining of the position of the UE 140 comprises determining a Direction-of-Arrival, DoA based on the determined channel information matrix.

[0071] According to another embodiment, the determining of the position of the UE 140 further comprises determining the position of the UE 140 based on the DoA determination performed by the calculating unit 190 and a DoA determination performed by another calculating unit 200, wherein the another calculating unit 200 is according to embodiment defined above, or the determining of the position of the UE 140 further comprise determining the position of the UE 140 based on at least two DoA determinations performed by the calculating unit 190 in at least two times.

[0072] According to another embodiment, the determining 306 of the channel information matrix further comprises determining multiple channel information in the antenna position A1 and averaging the multiple channel information.

[0073] According to another embodiment, the calculating unit 190 is arranged on the vehicle 130.

[0074] According to other embodiments, referring to fig.10, the control unit 180 may further comprise a communication unit 602, which may be considered to comprise conventional means for communication with external devices, such as a transceiver for transmission and reception of signals. The instructions executable by said processing circuitry 603 may be arranged as a computer program 605 stored e.g. in said memory 604. The processing circuitry 603 and the memory 604 may be arranged in a sub-arrangement 601. The sub-arrangement 601 may be a micro- processor and adequate software and storage therefore, a Programmable Logic Device, PLD, or other electronic component(s) / processing circuit(s) configured to perform the methods mentioned above. The processing circuitry 603 may comprise one or more programmable processor, application-specific integrated circuits, field programmable gate arrays or combinations of these adapted to execute instructions. The control unit 180 may also comprise a power supply, e.g., a battery.

[0075] The computer program 605 may be arranged such that when its instructions are run in the processing circuitry, they cause the control unit 180 to perform the steps described in any of the described embodiments of the control unit 180 and its method. The computer program 605 may be carried by a computer program product connectable to the processing circuitry 603. The computer program product may be the memory 604, or at least arranged in the memory. The memory 604 may be realized as for example a RAM (Random-access memory), ROM (Read-Only Memory) or an EEPROM (Electrical Erasable Programmable ROM). In some embodiments, a carrier may contain the computer program 605. The carrier may be one of an electronic signal, an optical signal, an electromagnetic signal, a magnetic signal, an electric signal, a radio signal, a microwave signal, or computer readable storage medium. The computer-readable storage medium may be e.g. a CD, DVD or flash memory, from which the program could be downloaded into the memory 604. Alternatively, the computer program may be stored on a server or any other entity to which the control unit 180 has access via the communication unit 602. The computer program 605 may then be downloaded from the server into the memory 604.

[0076] According to other embodiments, referring to fig.9, the calculating unit 190 may further comprise a communication unit 702, which may be considered to comprise conventional means for communication with external devices, such as a transceiver for transmission and reception of signals. The instructions executable by said processing circuitry 703 may be arranged as a computer program 705 stored e.g. in said memory 704. The processing circuitry 703 and the memory 704 may be arranged in a sub-arrangement 701. The sub-arrangement 701 may be a micro- processor and adequate software and storage therefore, a Programmable Logic Device, PLD, or other electronic component(s) / processing circuit(s) configured to perform the methods mentioned above. The processing circuitry 703 may comprise one or more programmable processor, application-specific integrated circuits, field programmable gate arrays or combinations of these adapted to execute instructions. The calculating unit 190 may also comprise a power supply, e.g., a battery.

[0077] The computer program 705 may be arranged such that when its instructions are run in the processing circuitry, they cause the calculating unit 190 to perform the steps described in any of the described embodiments of the calculating unit 190 and its method. The computer program 705 may be carried by a computer program product connectable to the processing circuitry 703. The computer program product may be the memory 704, or at least arranged in the memory. The memory 704 may be realized as for example a RAM (Random-access memory), ROM (Read-Only Memory) or an EEPROM (Electrical Erasable Programmable ROM). In some embodiments, a carrier may contain the computer program 705. The carrier may be one of an electronic signal, an optical signal, an electromagnetic signal, a magnetic signal, an electric signal, a radio signal, a microwave signal, or computer readable storage medium. The computer-readable storage medium may be e.g. a CD, DVD or flash memory, from which the program could be downloaded into the memory 704. Alternatively, the computer program may be stored on a server or any other entity to which the calculating unit 190 has access via the communication unit 702. The computer program 705 may then be downloaded from the server into the memory 704.

[0078] Although the description above contains a plurality of specificities, these should not be construed as limiting the scope of the concept described herein but as merely providing illustrations of some exemplifying embodiments of the described concept. It will be appreciated that the scope of the presently described concept fully encompasses other embodiments which may become obvious to those skilled in the art, and that the scope of the presently described concept is accordingly not to be limited. Reference to an element in the singular is not intended to mean "one and only one" unless explicitly so stated, but rather "one or more." Further, the term “a number of”, such as in “a number of wireless devices” signifies one or more devices. All structural and functional equivalents to the elements of the above- described embodiments that are known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed hereby. Moreover, it is not necessary for an apparatus or method to address each and every problem sought to be solved by the presently described concept, for it tobe encompassed hereby. In the exemplary figures, a broken line generally signifies that the feature within the broken line is optional.

Claims

CLAIMS 1. A method performed by a control unit (180) arranged on a vehicle (130), for determining a channel information matrix of wireless communication channels between a User Equipment, UE (140) and multiple antennas (142, 144) arranged on the vehicle (130), the control unit (180) being arranged to make measurements of phase and amplitude of reference signals, received from the UE (140) by the multiple antennas (142, 144), the method comprises: - making (204) a first measurement at a first measuring position (162, 166, 170), - making (206) a second measurement at a second measuring position (164, 168, 172), wherein the first and second measurement positions (162, 166, 170, 164, 168, 172) spatially overlap in at least one antenna position (A1).

2. A method performed by a calculating unit (190) for determining a channel information matrix of wireless communication channels between a User Equipment, UE (140) and multiple antennas (142, 144) arranged on a vehicle (130), the vehicle (130) being arranged to make measurements of phase and amplitude of reference signals, received from the UE (140) by the multiple antennas (142, 144), the method comprises: - obtaining (304) a first and a second measurement from the vehicle (130); - determining (306) the channel information matrix based on the obtained first and second measurements, wherein the first and second measurements being made in a first and second measuring positions (162, 164), the first and second measuring positions (162, 164) spatially overlap in an antenna position (A1), wherein the determining (306) of the channel information matrix comprises eliminating a phase error in channel information of the channel information matrix based on the first and second measurements.

3. The method according to claim 2, the method further comprises: - determining (308) a position of the UE (140) based on the determined channel information matrix.

4. The method according to claim 3, the determining (308) of the position of the UE (140) comprises determining a Direction-of-Arrival, DoA based on the determined channel information matrix.

5. The method according to claim 4, the determining (308) of the position of the UE (140) further comprises determining the position of the UE (140) based on the DoA determination performed by the calculating unit (190) and a DoA determination performed by another calculating unit (200), wherein the another calculating unit (200) is operative for performing the method as claimed in claim 4, or the determining (308) of the position of the UE (140) further comprises determining the position of the UE (140) based on at least two DoA determinations performed by the calculating unit (190) in at least two times.

6. The method according to any one of claims 2-5, wherein the determining (306) of the channel information matrix further comprises determining multiple channel information in the antenna position (A1) and averaging the multiple channel information.

7. A control unit (180) arranged on a vehicle (130), for determining a channel information matrix of wireless communication channels between a User Equipment, UE (140) and multiple antennas (142, 144) arranged on the vehicle (130), the control unit (180) comprises a processing circuitry (603) and a memory (604), the memory (604) containing instructions executable by the processing circuitry (603), the control unit (180) being arranged to make measurements of phase and amplitude of reference signals, received from the UE (140) by the multiple antennas (142, 144), whereby the control unit (180) is operative for: - making a first measurement at a first measuring position (162, 166, 170), - making a second measurement at a second measuring position (164, 168, 172), wherein the first and second measurement positions (162, 166, 170, 164, 168, 172) spatially overlap in at least one antenna position (A1).

8. The control unit (180) according to claim 7, wherein the vehicle (130) is an ariel vehicle, a land vehicle or a vessel.

9. A computer program (605) comprising instructions, which, when executed by a processing circuitry (603) of a control unit (180), for determining a channel information matrix of wireless communication channels between a User Equipment, UE (140) and multiple antennas (142, 144) arranged on the vehicle (130), the control unit (180) being arranged to make measurements of phase and amplitude of reference signals, received from the UE (140) by the multiple antennas (142, 144), causes the control unit (180) to perform the following steps: - making a first measurement at a first measuring position (162, 166, 170), - making a second measurement at a second measuring position (164, 168, 172), wherein the first and second measurement positions (162, 166, 170, 164, 168, 172) spatially overlap in at least one antenna position (A1).

10. A carrier containing the computer program (605) according to claim 9, wherein the carrier is one of an electronic signal, an optical signal, a radio signal, an electric signal, or a computer readable storage medium.

11. A calculating unit (190) for determining a channel information matrix of wireless communication channels between a User Equipment, UE (140) and multiple antennas (142, 144) arranged on a vehicle (130), the calculating unit (190) comprises a processing circuitry (703) and a memory (704), the memory (704) containing instructions executable by the processing circuitry (703), the vehicle (130) being arranged to make measurements of phase and amplitude of reference signals, received from the UE (140) by the multiple antennas (142, 144), whereby the calculating unit (190) is operative for: - obtaining a first and a second measurement from the vehicle (130); - determining the channel information matrix based on the obtained first and second measurements, wherein the first and second measurements being made in a first and second measuring positions (162, 164), the first and secondmeasuring positions (162, 164) spatially overlap in an antenna position (A1), wherein the determining of the channel information matrix comprises eliminating a phase error in channel information of the channel information matrix based on the first and second measurements.

12. The calculating unit (190) according to claim 11, the calculating unit (190) is further operative for: - determining a position of the UE (140) based on the determined channel information matrix.

13. The calculating unit (190) according to claim 12, the determining of the position of the UE (140) comprises determining a Direction-of-Arrival, DoA based on the determined channel information matrix.

14. The calculating unit (190) according to claim 13, the determining of the position of the UE (140) further comprises determining the position of the UE (140) based on the DoA determination performed by the calculating unit (190) and a DoA determination performed by another calculating unit (200), wherein the another calculating unit (200) is according to claim 13, or the determining of the position of the UE (140) further comprise determining the position of the UE (140) based on at least two DoA determinations performed by the calculating unit (190) in at least two times.

15. The calculating unit (190) according to any one of claims 11-14, wherein the determining (306) of the channel information matrix further comprises determining multiple channel information in the antenna position (A1) and averaging the multiple channel information.

16. The calculating unit (190) according to any one of claims 11-15, wherein the calculating unit (190) is arranged on the vehicle (130).

17. A computer program (705) for determining a channel information matrix of wireless communication channels between a User Equipment, UE (140) and multiple antennas (142, 144) arranged on a vehicle (130), the vehicle (130) being arranged to make measurements of phase and amplitude of reference signals, received from the UE (140) by the multiple antennas (142, 144), when executed by a processing circuitry (703) of a calculating unit (190), causes the calculating unit (190) to perform the following steps: - obtaining a first and a second measurement from the vehicle (130); - determining the channel information matrix based on the obtained first and second measurements, wherein the first and second measurements being made in a first and second measuring positions (162, 164), the first and second measuring positions (162, 164) spatially overlap in an antenna position (A1), wherein the determining of the channel information matrix comprises eliminating a phase error in channel information of the channel information matrix based on the first and second measurements.

18. A carrier containing the computer program (705) according to claim 17, wherein the carrier is one of an electronic signal, an optical signal, a radio signal, an electric signal, or a computer readable storage medium.

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