WO2020091637A1

WO2020091637A1 - Handling directions of receiver beam scanning of an antenna array

Info

Publication number: WO2020091637A1
Application number: PCT/SE2018/051103
Authority: WO
Inventors: Iana Siomina; Katrina Lau; Ramon DELGADO; Richard MIDDLETON; Torbjörn WIGREN
Original assignee: Telefonaktiebolaget LM Ericsson AB
Current assignee: Telefonaktiebolaget LM Ericsson AB
Priority date: 2018-10-29
Filing date: 2018-10-29
Publication date: 2020-05-07
Anticipated expiration: 2021-04-29
Also published as: EP3874617A4; EP3874617A1

Abstract

A method by a first network node (101), for handling directions of receiver beam scanning by an antenna array in a first radio network node (111). Both nodes operate in a wireless communications network (100). The first network node (101) determines (503), out of a set of directions in which the first radio network node (111) is capable of beam scanning, a subset of directions of beam scanning having a probability of detection above a threshold, of a signal received from a first wireless device (131). The determining (503) is based on data obtained from previous attempts of positioning one or more second wireless devices (132) using at least some of the directions. The first network node (101) also initiates (504) providing, to at least one of: the first radio network node (111) and a second network node (102) operating in the wireless communications network (100), an indication of the determined subset.

Description

Handling directions of receiver beam scanning of an antenna array

TECHNICAL FIELD

The present disclosure relates generally to a first network node and methods performed thereby for handling directions of receiver beam scanning of an antenna array in a first radio network node. Further particularly, the present disclosure relates generally to a first network node and methods performed thereby for handling directions of receiver beam scanning of an antenna array in a first radio network node, for the purpose of positioning a first wireless device.

BACKGROUND

Wireless devices within a wireless communications network may be e.g., User Equipments (UE), stations (STAs), mobile terminals, wireless terminals, terminals, and/or Mobile Stations (MS). Wireless devices are enabled to communicate wirelessly in a cellular communications network or wireless communication network, sometimes also referred to as a cellular radio system, cellular system, or cellular network. The

communication may be performed e.g., between two wireless devices, between a wireless device and a regular telephone and/or between a wireless device and a server via a Radio Access Network (RAN) and possibly one or more core networks, comprised within the wireless communications network. Wireless devices may further be referred to as mobile telephones, cellular telephones, laptops, or tablets with wireless capability, just to mention some further examples. The wireless devices in the present context may be, for example, portable, pocket-storable, hand-held, computer-comprised, or vehicle-mounted mobile devices, enabled to communicate voice and/or data, via the RAN, with another entity, such as another terminal or a server.

The wireless communications network covers a geographical area which may be divided into cell areas, each cell area being served by a network node, which may be an access node such as a radio network node, radio node or a base station, e.g., a Radio Base Station (RBS), which sometimes may be referred to as e.g., evolved Node B (“eNB”),“eNodeB”,“NodeB”,“B node”, gNB, Transmission Point (TP), or BTS (Base Transceiver Station), depending on the technology and terminology used. The base stations may be of different classes such as e.g., Wide Area Base Stations, Medium Range Base Stations, Local Area Base Stations, Home Base Stations, pico base stations, etc... , based on transmission power and thereby also cell size. A cell is the geographical area where radio coverage is provided by the base station or radio node at a base station site, or radio node site, respectively. One base station, situated on the base station site, may serve one or several cells. Further, each base station may support one or several communication technologies. The base stations communicate over the air interface operating on radio frequencies with the terminals within range of the base stations. The wireless communications network may also be a non-cellular system, comprising network nodes which may serve receiving nodes, such as wireless devices, with serving beams. In 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE), base stations, which may be referred to as eNodeBs or even eNBs, may be directly connected to one or more core networks. In the context of this disclosure, the expression Downlink (DL) may be used for the transmission path from the base station to the wireless device. The expression Uplink (UL) may be used for the transmission path in the opposite direction i.e., from the wireless device to the base station.

Positioning

UE positioning is recognized as an important feature for LTE networks due to its potential for massive user applications, for example, intelligent transportation,

entertainment, industry automation, robotics, remote operation, healthcare, smart parking and so on, as well as its relevance to the United States Federal Communications

Commission (US FCC) E91 1 requirements.

Positioning in LTE may be supported by the architecture in shown in Figure 1 , with direct interactions between a UE 10 and a location server, the Evolved Serving Mobile Location Center (E-SMLC) 1 1 , via the LTE Positioning Protocol (LPP) 12. Moreover, there may be also interactions between the location server and the eNodeB 13 via the LTE Positioning Protocol A (LPPa) 14, to some extent supported by interactions between the eNodeB 13 and the UE 10 via the Radio Resource Control (RRC) protocol 15. The eNodeB 13 and the E-SMLC 1 1 may also communicate with a Mobility Management Entity (MME) 16, which in turn communicates with a Gateway Mobile Location Centre (GMLC) 17.

In LTE, as described e.g., in 3GPP Technical Specification 36.305, v.14.1.0, several positioning techniques may be considered. A first technique is the Enhanced Cell Identity (ID). Through this technique, cell ID information may be used to associate the UE to the serving area of a serving cell, and then additional information may be used to determine a finer granularity position. Another technique is assisted Global Navigation Satellite System (GNSS). GNSS may be understood to encompass all systems that may provide worldwide positioning based on satellites, including, for example, the Global Positioning System (GPS), the Global Navigation Satellite System (GLONASS) and Galileo. In this technique, GNSS information may be retrieved by the UE, and it may be supported by assistance information provided to the UE from the E-SMLC.

Another technique is the Observed Time Difference of Arrival (OTDOA). In this technique, the UE may estimate the time difference of reference signals from different base stations and may send the result of the estimation to the Evolved Serving Mobile Location Center (E-SMLC) for multilateration.

Yet another technique is the Uplink TDOA (UTDOA). In this technique, the UE may be requested to transmit a specific waveform that may be detected by multiple location measurement units, e.g. an eNB, at known positions. These measurements may be forwarded to the E-SMLC for multilateration.

NR

The so-called 5G system, from a radio perspective started to be standardized in 3GPP, and the so-called New Radio (NR) is the name for the radio interface. NR architecture is being discussed in 3GPP. In the current concept, gNB denotes NR BS, where one NR BS may correspond to one or more transmission/reception points. In the coming 4G and in the emerging 5G cellular systems, beamforming and MIMO

transmission will be central technologies. The reason in the 4G case is a desire for increased capacity. This can be obtained by the introduction of advanced antenna systems (AAS) and running MIMO-schemes. In addition, spectral resources are running out at low carrier frequencies which leads to a gradual migration into higher frequency bands. As the low carrier frequency bands were already deployed with 2G, 3G and 4G wireless communication systems, NR will be deployed at relatively higher frequencies than LTE. In the 5G case, the millimeter wave (mmW) band will be used as well. There is e.g. plenty of available spectrum around 28 GHz and 39 GHz in the US and other areas. This spectrum may need to be exploited to meet the increasing capacity requirements. The 5G frequency migration is expected to start at 3.5 - 5 GHz, and then continue to these 28 GHz and 39 GHz bands that are expected to become available soon.

Communication at higher frequencies, e.g., above 6 GHz, is known to have more challenging propagation conditions such as a higher penetration loss. For wireless communication, the propagation loss may be roughly proportional to the square of the carrier frequency. Hence there may be coverage issues for wireless communication over high carrier frequencies. At high frequencies, beamforming and a use of massive antenna arrays may be needed to achieve a sufficient coverage.

Beamforming and MIMO

Multi-antenna techniques may significantly increase the data rates and reliability of a wireless communication system. The performance is in particular improved if both the transmitter and the receiver are equipped with multiple antennas, which results in a multiple-input multiple-output (MIMO) communication channel. Such systems and/or related techniques are commonly referred to as MIMO.

The 5th Generation (5G) technology, which is currently being developed, incorporates the use of beamforming. Beamforming may be understood as a signal processing technique which relies on combining elements in an array antenna in such a way that signals at particular angles experience constructive interference while others experience destructive interference. An array antenna may consist of many antenna elements to achieve a large array gain. Many antenna elements may participate in forming a beam, and the beams are typically highly directive, giving beamforming gains of 20 decibels (dB) or more. Each Transmission Point (TP) may, by use of an array antenna, generate transmission of a large number of beams having different pointing directions and/or polarizations. As the number of antennas increases, the energy may be focused with extreme precision into small regions in space. The result is spatial selectivity, such that beamforming may be understood as a way to transmit a signal with such narrow beams that it is intended for a single wireless device or a group of wireless devices in a similar geographical position. In 5G systems, the number of antenna elements at the transmitter and/or receiver side may be significantly increased compared to common 3G and 4G systems.

Figure 2 is a schematic diagram representing an antenna array that may be used for beamforming. The diagram of Figure 2 shows an idealized one-dimensional receiver beamforming case. In case it is assumed that an UE 20 is located far away from the antenna array 25 it follows that the difference in travel distance from the UE 20 to the base station where the array 25 is located, between adjacent antenna elements, is l = kl sin(f?), where ^ is the antenna element separation. Here ^ is the separation factor which may be 0.5-0.7 in a typical correlated antenna element arrangement. This means that if a reference signal S_UE is transmitted from the UE 20, it may be received at the i:th antenna element as the signal

Here w is the angular carrier frequency, h_t is the complex channel from the i:th antenna element, / is the time, and f_c is the carrier frequency. In the above equation Q and h_t are unknown. The above equation may be recognized to be very similar to the terms of a discrete Fourier transform. This may be understood to mean that if the weights of the downlink codebook are applied to the signal sample of each antenna element, and summed, a discrete Fourier transform may be carried out. As is well known, when the angles of the codebook correspond to an angle closest to Q in the codebook, the terms may interfere constructively and result in a Fourier transformed signal with high signal to noise ratio, which may be understood to mean that it may be detected e.g., in a Signal to Interference plus Noise Ratio (SINR) detector or a power detector. The above procedure may be known as a transformation to beamspace, from the antenna element signals.

When the UE pilot signal is received, the base station may thus apply the beamspace transformation for all entries of the codebook it may have stored and defined, and perform a search over all codebook entries to find a set of beams with high enough SINR, or simply the one with the highest SINR. This implies that the price paid in the base station in case there are many alternative beams to scan, may be search complexity. If the hardware resources are scarce, this may carry over to processing latency. The base station thus may need to search for all complex channel coefficients h_t and the unknown angle Q . For this reason, the standard defines a codebook of beams in different directions given by steering vector coefficients such as:

where m indicates a directional codebook entry. The UE 20 may then test each codebook and estimate the channel coefficients. The information rate achieved for each codebook entry m may be computed, and the best one may be understood to define the direction and channel coefficients. This may be possible since the signal S_UE is known. This may provide the base station with a best direction, that is, a codebook entry, and information that may allow it to build up a channel matrix H . This matrix may be understood to represent the channel from each of the transmit antenna elements to each of the receive antenna elements. Typically, each element of H is represented by a complex number. Reference signals supporting codebook based beamforming in downlink

The description of the present subsection is given in terms of the 3GPP terminology for the 4G LTE system. The 5G functionality may be understood to correspond to that provided in the 4G system. Codebooks may also be exploited to perform the beam space transform discussed above.

The Channel State Information Reference Signals (CSI-RS), which have been available since release 1 1 , may be assigned to a specific antenna port. These reference signals may be transmitted to the whole cell, or may be beamformed in a UE specific manner. In 3GPP from release 13, two classes of CSI-RS reporting modes have been0 introduced: class A CSI-RS may be understood to refer to the use of fixed-beam

codebook based beamforming, while a class B CSI-RS process may send beamformed CSI-RS in any manner.

A CSI-RS process in a UE may comprise detection of selected CSI-RS signals, measuring interference and noise on Channel State Information Interference

5 Measurement (CSI-IM), and reporting of the related CSI information, in terms of Channel Quality Indication (CQI), Pre-coder Matrix Index (PMI), and (channel matrix) Rank Indication (Rl), that is the selected codebook entry. A UE may report more than one set of CQI, Rl and PMI, that is, information for more than one codebook entry. Up to 4 CSI- RS processes may be set up for each UE, starting in 3GPP release 1 1.

0 2D codebooks and antenna port relations

The description of the present subsection is given in terms of the 3GPP terminology for the 4G LTE system. The 5G functionality may be understood to correspond to that provided in the 4G system.

As stated above, the codebook of the 3GPP standard is defined to represent certain5 directions. In release 13, directions in both azimuth and elevation are defined, thereby allowing 2D beamforming to be used. These 4G codebooks are specified in detail in 3GPP TR 36.897. A similar definition, but with finer granularity is expected for the 3GPP 5G standard.

To illustrate that the codebooks indeed define specific directions, it may be noted that the formula for the azimuth codebook is

It has the same structure as discussed above. Similarly, the vertical codebook in that document is given by

In the two above equations, it is only the structure that is needed here, the details of the involved quantities are of less importance and are not reproduced here, see 3GPP TR 36.897 for all details. Finally, it may be noted that a 2D beam may be obtained by a multiplication of the two above equations.

TDOA positioning methods

The major conceptual difference between uplink time difference of arrival (UTDOA) and observed time difference of arrival (OTDOA) may be understood to be that the latter may require multiple transmit points whilst the former may utilize multiple receive points at different locations, typically base stations, although the position calculation principle is the same.

UTDOA positioning measurements

In LTE, the UTDOA method may be based on the transmission of sounding reference signals (SRSs) by the UE, which may be measured on by multiple base stations or by so called Location Measurement Units (LMUs). Multiple samples may be typically needed at each measuring node to achieve an acceptable accuracy, which may require some time until the measurement may be considered to be complete. In, NR, the support for UTDOA is yet to be standardized, so it has not be yet decided which signals are to be used for UTDOA in NR.

Real time differences

The wireless network where UTDOA may be deployed may not be perfectly synchronized. The time differences between the base stations and between the UE and the base station may then need to be compensated for. The clock bias of the UE may be handled by forming differences of the time of arrival measurements in the UE or in the base stations. This implies that the UE clock bias with respect to the reference time system disappears from the positioning equations. The differences in time between the different base stations may be denoted real time differences. These may be obtained from so called Location Measurement Units (LMUs) that may be understood to be located at known positions with clocks aligned to the currently applied time base. By listening to the base stations, it may then become possible to compute and track the real time differences, by solving the positioning equations for the real time differences.

UTDOA positioning principle The major conceptual difference between uplink time difference of arrival (UTDOA) and observed time difference of arrival (OTDOA) is that the latter may require multiple transmit points, whilst the former may be understood to utilize multiple receive points at different locations, typically BS locations, although the position calculation principle is the same. To describe the position calculation of the UTDOA method, Figure 3 may be considered. Figure 3 is a schematic diagram illustrating a setup for the discussion herein of UTDOA position calculation methods. In Figure 3, a UE 30, which may be referred to herein as the“terminal”, and a number of base stations 35 are schematically represented, as well as a number of cells 37, served by the base stations 35. Each time difference of arrival equation is represented in Figure 3 as an hyperbole. The user location is resolved by finding the intersection of these hyperboles. The discontinued lines may represent the distance ||r1 -rterminal|| in the following equations. Since this distance is captured by the Time of arrival (TOA) measurements, the discontinued lines may be understood to also represent the TOA measurements. Assuming that the measurements are successful for a number of base stations 35, three of which are depicted in Figure 3, the following relations between the measured TOAs in the base stations 35 the transmission time from the UE 30, and the distances between the UE 30 and the measurement locations, typically the base stations 35, may follow:

^TOA,I Ί bclock transmit ,1 Ί ll^l ^terminal ll/^c t TOA,h + b, clock = T_t transmit, n Ί I n G terminal ll/c.

Here

i = l, . . . , n denotes the measured time of arrivals (TOAs) in the known measuring locations r, , i = I, . . , h , T_{transmit i} denotes the transmission time from the UE 30, and c is the speed of light. The boldface quantities are the (vector) locations of the base stations 35 and the UE 30. b_clock denotes the unknown clock bias of the UE 30 with respect to cellular system time. Now, in UTDOA positioning, time of arrival differences with respect to the own site may be formed according to:

In these n-1 equations, the left hand sides are known, with some additional measurement error, provided that the time of transmission difference between the network and UE time may be measured. It may be noted that real time differences, i.e. differences in the time base between the base stations are neglected here. These are normally measured with dedicated hardware, the so called location measurement units (LMUs), or by other procedures. In case of a synchronized network, the difference may be understood to be known. Further, the locations of the measurement locations, r, , i = 1

, may be surveyed to within a few meters and so they are known as well. What remains unknown is the location of the UE 30, that is,

In the more common case, a two-dimensional positioning may be performed, then the unknown position may be instead:

^Terminal y ^Terminal T Terminal )

It then follows that at least three time of arrival differences may be needed in order to find a 3D terminal position, and that at least two time of arrival differences may be needed in order to find a 2D terminal position. This, in turn, may be understood to mean that at least four sites may need to be detected for 3D terminal positioning and at least three sites may need to be detected for 2D terminal positioning. In practice, accuracy may be improved if more measurements are collected, and a maximum likelihood solution is introduced. There may also be multiple false solutions in cases where only a minimum number of sites may be detected.

A problem with all terrestrial time difference of arrival positioning methods may be to detect/be detected in a sufficient number of non-colocated locations. It may be noted that the theoretical minimum of three neighbor locations may not be enough in practice. In many situations, the number of neighbors may be twice this figure to obtain a reliable performance.

A challenge with the presently available existing positioning methods is that the wireless system is designed with cell ranges that are consistent with the maximum beam gain that may be obtained from an antenna array with N elements. Where each cell is designed to provide coverage to a certain geographical area, a cell range may be understood to refer to the maximum range at which a user may“hear” a given base station.. Therefore, unless the pilot signals are transmitted/received with a maximum beam gain, they may not be detectable at the cell edge, meaning that the ability to detect neighbor sites may be compromised unless high gain beamforming is used for all sites involved in the UTDOA positioning. Furthermore, since the UE is to be positioned, there is no knowledge about where to point the beams. This may be understood to mean that all possible beam directions need to be scanned, for each site. This scanning may quickly becomes troublesome when the number of involved positioning nodes increases, since the processing consumes resources. The processing that may be needed may alsoincrease the positioning latency.

SUMMARY

It is an object of embodiments herein to improve methods of determining a location of a wireless device in a wireless communications network. It is a particular object of embodiments herein to improve the handling of directions of receiver beam scanning of an antenna array in a wireless communications network for positioning purposes.

According to a first aspect of embodiments herein, the object is achieved by a method performed by a first network node. The method is for handling directions of beam scanning by an antenna array in a first radio network node. The first network node and the first radio network node operate in a wireless communications network. The first network node determines, out of a set of directions in which the first radio network node is capable of beam scanning, a subset of directions of beam scanning. The subset of directions of beam scanning have a probability of detection above a threshold, of a signal received from a first wireless device operating in the wireless communications network. The determining is based on data obtained from previous attempts of positioning one or more second wireless devices using at least some of the directions in the set of directions. The first network node further initiates providing, to at least one of: the first radio network node and a second network node operating in the wireless communications network 100, an indication of the determined subset.

According to a second aspect of embodiments herein, the object is achieved by the first network node, configured to handle directions of receiver beam scanning of an antenna array configured to be in the first radio network node. The first network node and the first radio network node are configured to operate in the wireless communications network. The first network node is further configured to determine, out of the set of directions in which the first radio network node is configured to be capable of beam scanning, the subset of directions of beam scanning. The subset is configured to have the probability of detection above the threshold, of the signal configured to be received from the first wireless device. The first wireless device is configured to operate in the wireless communications network. To determine is configured to be based on the data configured to be obtained from the previous attempts of positioning the one or more second wireless devices using at least some of the directions in the set of directions. The first network node is further configured to initiate providing, to at least one of: the first radio network node and the second network node configured to operate in the wireless communications network, the indication of the subset configured to be determined.

By the first network node determining the subset of directions of beam scanning having the probability of detection of the signal above the threshold, out of the set of directions in which the first radio network node is capable of beam scanning, and then providing the indication to the first radio network node, the radio network nodes may be enabled to refrain from beam scanning in many of the directions of the set. This enables substantial savings in terms of scan time, which in turn results in reduced processing time. Therefore, the latency, energy and processing resources of the system are reduced, while the capacity is increased, improving the performance of the wireless communications network.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of embodiments herein are described in more detail with reference to the accompanying drawings, according to the following description.

Figure 1 is a schematic diagram illustrating an LTE positioning architecture.

Figure 2 is a schematic diagram representing an antenna array that may be used for beamforming.

Figure 3 is a schematic diagram illustrating a setup of UTDOA position calculation

methods.

Figure 4 is a schematic diagram illustrating embodiments of a wireless communications network, according to embodiments herein.

Figure 5 is a flowchart depicting a method in a first network node, according to

embodiments herein.

Figure 6 is a schematic diagram illustrating cell geometry and user paths, according to an example of embodiments herein. Figure 7 is a beam direction histogram for a site position Figure 6.

Figure 8 is a schematic diagram illustrating the site locations and geometry of mmW

simulations, according to embodiments herein.

Figure 9 is a beam direction histogram for site position x=15, y=18 in Figure 8.

Figure 10 is a beam direction histogram for site position x=30, y=10 in Figure 8.

Figure 1 1 is a beam direction histogram for site position x=46, y=1 in Figure 8.

Figure 12 is a beam direction histogram for site position x=0, y=21 in Figure 8.

Figure 13 is a three-dimensional histogram of the joint likelihood of a first and second beam direction, according to embodiments herein.

Figure 14 is a two-dimensional histogram of the joint likelihood of a first and second beam direction, according to embodiments herein.

Figure 15 is a diagram depicting a second threshold, that is, a false alarm detection

threshold as a function of the dimension of the search space

Figure 16 is a schematic block diagram illustrating embodiments of a first network node, according to embodiments herein.

DETAILED DESCRIPTION

Before describing embodiments herein in detail, one or more terms used herein will first be described.

Embodiments herein address the problems of the existing solutions. To address these challenges, embodiments herein may be understood to relate to providing a beamforming learning method that reduces the scanning that may be needed for UTDOA positioning. At the same time, the sensitivity of the UTDOA position measurements may be understood to be improved. Embodiments herein may be understood to exploit beamforming opportunities that may arise in both the high mmW frequency bands and the lower 4G and 5G bands, below 6 GHz. The improved beam scanning provided may be integrated into an uplink time-difference-of-arrival (UTDOA) positioning method. In particular, embodiments herein disclose receiver beam scanning methods and search techniques that may significantly reduce the multi-site scanning complexity and thereby the latency, when applying UTDOA positioning. A further advantage of embodiments herein may be understood to be that the sensitivity of UTDOA detections may be improved.

In brief, embodiments herein may be understood to relate to UTDOA beam scanning methods using estimated beam scanning direction statistics. Embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which examples are shown. In this section, the embodiments herein will be illustrated in more detail by a number of exemplary embodiments. It should be noted that the exemplary embodiments herein are not mutually exclusive. Components from one embodiment may be tacitly assumed to be present in another embodiment and it will be obvious to a person skilled in the art how those components may be used in the other exemplary embodiments.

Note that although terminology from 3GPP NR has been used in this disclosure to exemplify the embodiments herein, this should not be seen as limiting the scope of the embodiments herein to only the aforementioned system. Other wireless systems, including LTE, supporting the functionality described, may also benefit from exploiting the ideas covered within this disclosure.

Figure 4 depicts an example of a wireless communications network 100, sometimes also referred to as a cellular radio system, cellular network or wireless communications system, in which embodiments herein may be implemented. The wireless communications network 100 may for example be a 5G system, 5G network, NR or Next Gen System or network. The wireless communications network 100 may support operation with other networks such as a Long-Term Evolution (LTE) network, e.g., LTE Frequency Division Duplex (FDD), LTE Time Division Duplex (TDD), LTE Half-Duplex Frequency Division Duplex (HD-FDD), LTE operating in an unlicensed band, Wideband Code Division Multiple Access (WCDMA), Universal Terrestrial Radio Access (UTRA) TDD, Global System for Mobile communications (GSM) network, GSM/Enhanced Data Rate for GSM Evolution (EDGE) Radio Access Network (GERAN) network, Ultra-Mobile Broadband (UMB), EDGE network, network comprising of any combination of Radio Access Technologies (RATs) such as e.g. Multi-Standard Radio (MSR) base stations, multi-RAT base stations etc., any 3rd Generation Partnership Project (3GPP) cellular network, WiFi networks, Worldwide Interoperability for Microwave Access (WiMax), or any cellular network or system, which may be younger than 5G, yet capable to perform the functionality described. Thus, although terminology from 3GPP NR/LTE may be used in this disclosure to exemplify embodiments herein, this should not be seen as limiting the scope of the embodiments herein to only the aforementioned system. The wireless communications network 100 comprises a plurality of network nodes whereof a first network node 101 , and a second network node 102 are depicted in Figure 4.

The first network node 101 is a network node that has a capability to analyze beamforming information. The first network node 101 may typically be a core network node, although in some examples, it may be a radio network node. The first network node 101 may itself have a capability to perform location services. In a typical example, the first network node 101 may be a location server, such as an E-SMLC in LTE, 4G eSMLC, or 5G eSMLC. In another example, the first network node 101 may be an RTK GNSS server or an MME. Yet in another example, the first network node 101 may be radio network node, e.g., a gNB, a 4G eNB, or a 5G eNB.

The second network node 102 may be understood as another network node or radio network node with a capability to process and/or forward the information provided by the first network node 101. Any of the first network node 101 and the second network node 102 may be implemented as one or more distributed nodes, one or more of which may be virtual nodes in the cloud. In some examples, any of the first network node 101 and the second network node 102 may be co-localized, partly co-localized, or be the same network node. In some particular examples, the second network node 102 may be a core network node, e.g. an MME. Each of the first network node 101 and the second radio network node 1 12 may be connected to different core networks and be operated by the same or different operators.

The wireless communications network 100 also comprises a plurality of radio network nodes whereof a first radio network node 111 , and a second radio network node 112, as well as a third radio network node out of one or more third radio network nodes 113 are depicted in Figure 4. Only one of the one or more third radio network nodes 1 13 is illustrated in the non-limiting example of Figure 4 to simplify the figure.

Each of the first radio network node 1 1 1 , the second radio network node 1 12, and the one or more third radio network nodes 1 13 may typically be a base station or Transmission Point (TP) with beamforming capability, or any other network unit capable to serve, with serving beam-formed beams, a wireless device or a machine type node in the wireless communications network 100. Each of the first radio network node 1 11 , the second radio network node 1 12, and the one or more third radio network nodes 1 13 may be e.g., a gNB, a 4G eNB, or a 5G eNB. Any of the first radio network node 1 1 1 , the second radio network node 1 12, and the one or more third radio network nodes 1 13 may be e.g., a Wide Area Base Station, Medium Range Base Station, Local Area Base Station and Home Base Station, based on transmission power and thereby also coverage size. Any of the first radio network node 1 1 1 , the second radio network node 1 12, and the one or more third radio network nodes 1 13 may be a stationary relay node or a mobile relay node. Any of the first radio network node 1 1 1 , the second radio network node 1 12, and the one or more third radio network node 1 13s may support one or several

communication technologies, and its name may depend on the technology and terminology used. Any of the first radio network node 1 1 1 , the second radio network node 1 12, and the one or more third radio network nodes 1 13 may be directly connected to one or more networks and/or one or more core networks.

The wireless communications network 100 covers a geographical area which may be divided into cell areas, wherein each cell area may be served by a network node, although, one radio network node may serve one or several cells. In the non-limiting example depicted in Figure 4, the first radio network node 1 1 1 serves a first cell 121 , the second radio network node 1 12 serves a second cell 122, and the third radio network node 1 13 serves a third cell 123. It may be understood that each of the one or more third radio network nodes 1 13 may serve a respective third cell.

The wireless communications network 100 comprises a first wireless device 131. The wireless communications network 100 may have also comprised in a past time period, or may comprise in a contemporaneous time period to the presence of the first wireless device 131 , one or more second wireless devices 132 and/or one or more third wireless devices 133. In the non-limiting example scenario of Figure 4, the one or more second wireless devices 132 and the one or more third wireless devices 133 have been comprised in the wireless communications network 100 in a previous time period, and are therefore represented with dotted lines. In the non-limiting example scenario of Figure 4 three second wireless devices 132, and three third wireless devices, respectively 133 are represented for illustrative purposes only. The number of one or more second wireless devices 132 and/or the one or more third wireless devices 133 may vary. Any of the first wireless device 131 , the one or more second wireless devices 132 and/or the one or more third wireless devices 133 may be also known as e.g., a UE, mobile terminal, wireless terminal and/or mobile station, mobile telephone, cellular telephone, or laptop with wireless capability, or a Customer Premises Equipment (CPE), just to mention some further examples. Any of the first wireless device 131 , the one or more second wireless devices 132 and/or the one or more third wireless devices 133 in the present context may be, for example, portable, pocket-storable, hand-held, computer-comprised, or a vehicle- mounted mobile device, enabled to communicate voice and/or data, via a RAN, with another entity, such as a server, a laptop, a Personal Digital Assistant (PDA), or a tablet computer, sometimes referred to as a tablet with wireless capability, or simply tablet, a Machine-to-Machine (M2M) device, a device equipped with a wireless interface, such as a printer or a file storage device, modem, Laptop Embedded Equipped (LEE), Laptop Mounted Equipment (LME), USB dongles, CPE or any other radio network unit capable of communicating over a radio link in the wireless communications network 100. Any of the first wireless device 131 , the one or more second wireless devices 132 and/or the one or more third wireless devices 133 may be wireless, i.e., it may be enabled to communicate wirelessly in the wireless communication network 100 and, in some particular examples, may be able support beamforming transmission. The communication may be performed e.g., between two devices, between a device and a network node, and/or between a device and a server. The communication may be performed e.g., via a RAN and possibly one or more core networks, comprised within the wireless

communications network 100.

In some examples, some or all of the one or more second wireless devices 132 may be the same as some or all of the one or more third wireless devices 133. They are named differently to denote the two groups do not necessarily refer to the same wireless devices. The one or more second wireless devices 132 may comprise one or more simulated wireless devices. In some particular examples, the one or more second wireless devices 132 may comprise the simulated device, or simulated devices, and the one or more third wireless devices 133.

The first network node 101 may communicate with the first radio network node 1 1 1 over a first link 141 , e.g., a radio link or a wired link. The first network node 101 may communicate with the second radio network node 1 12 over a second link 142, e.g., a radio link or a wired link. The first network node 101 may communicate with the third radio network node 1 13 over a third link 143, e.g., a radio link or a wired link. The first network node 101 may communicate with the third radio network node 1 13 over a respective third link, e.g., a radio link or a wired link. The first wireless device 131 may communicate with the first radio network node 1 1 1 over a fourth link 144, e.g., a radio link. The first wireless device 131 may communicate with the second radio network node 1 12 over a fifth link 145, e.g., a radio link. The first wireless device 131 may

communicate with the third radio network node 1 13 over a sixth link 146, e.g., a radio link. Each of the first link 141 , the second link 142, and the third link 143 may be a direct link or a comprise one or more links, e.g., via one or more other network nodes, radio network nodes or core network nodes.

Each of the one or more wireless devices 132, and/or the one or more third wireless devices 133 may communicate or have communicated with to any of the first radio network node 1 1 1 , the second radio network node 1 12, and any of the one or more third radio network nodes 1 13 with similar links to those described for the wireless device 131. These are not depicted in Figure 4 to simplify it.

In general, the usage herein of“first”,“second”,“third”,“fourth”,“fifth” and/or“sixth” may be understood to be an arbitrary way to denote different elements, and may be understood to not confer a cumulative or chronological character to the elements they modify.

Embodiments of a method, performed by the first network node 101 , will now be described with reference to the flowchart depicted in Figure 5. The method may be understood to be for handling directions of receiver beam scanning of an antenna array in a first radio network node 1 1 1. The first network node 101 and the first radio network node 1 1 1 operate in the wireless communications network 100.

In some embodiments, all the actions may be performed. In some embodiments, some actions may be performed. One or more embodiments may be combined, where applicable. All possible combinations are not described to simplify the description. It should be noted that the examples herein are not mutually exclusive. Components from one embodiment may be tacitly assumed to be present in another embodiment and it will be obvious to a person skilled in the art how those components may be used in the other exemplary embodiments. In Figure 5, optional actions are indicated with dashed lines. Some actions may be performed in a different order than that shown in Figure 5.

Action 501

In the course of communications within the wireless communications network 100, the first network node 101 may at some point need to determine a location of the first wireless device 131. As explained earlier, one of the methods that may be used to determine the location of the first wireless device 131 may rely on a detection of a signal that may be transmitted by the first wireless device 131. The signal may be, as described earlier e.g., an SRS.

It may be understood that“the signal” is used in the singular form to refer generically to a type of signal, but not necessarily to convey that a single signal, e.g., a single SRS, is received. The method may be understood to be UTDOA. In the embodiments described herein, it is assumed that UTDOA may be based on UL transmissions, which herein may be understood to comprise one or more of signals and/or channels transmitted by the first wireless device 131 whose transmissions may be used for positioning purpose, e.g., sounding reference signals, UL positioning reference signals, demodulation reference signals, DeModulation Reference Signal (DM-RS), phase-tracking reference signals, Phase Tracking Reference Signal (PT-RS), timing reference signal, Tracking Reference Signal (TRS), Physical Uplink Control Channel (PUCCH), Physical Uplink Shared Channel (PUSCH), Physical Random Access Channel (PRACH), etc. Herein, SRS are used as an example of any of these signals. Hence, any reference herein to the term SRS may be understood to equally applied to any of these UL transmissions. Note that the term“SRS”, as used herein, is therefore broader than the term“SRS” used to denote a specific UL reference signal in LTE. As described earlier, at least three radio network nodes, such as the first radio network node 1 1 1 , the second radio network node 1 12, and the third radio network node 1 13, may need to be used to for 2D terminal positioning of the first wireless device 131. Since the location of the first wireless device 131 to be positioned is not yet known at this stage, the first radio network node 1 1 1 , the second radio network node 1 12 and the third radio network node 1 13 may have no knowledge about where to perform receiver beam scanning in order to detect the signal that may be received from the first wireless device 131. The first radio network node 1 1 1 , for example, is capable of beam scanning in a set of directions. The method is described herein in relation to the first radio network node 1 1 1 to simplify the description. However, the method may be understood to similarly apply to each of the second radio network node 1 12 and the one or more third radio network nodes 1 13. To avoid having to perform beam scanning in all possible directions, and test which directions are capable of detecting the signal received from the first wireless device 131 , it would be helpful to narrow down the number of directions to scan, to a smaller number of directions, that is, to a subset of directions from the set of possible directions. For that purpose, the first network node 101 may use data obtained from previous attempts of positioning other wireless devices, that is, the one or more second wireless devices 132, as will be described in the following actions.

In some embodiments, according to embodiments herein, the first network node 101 may perform data simulations, to try to estimate what subset of directions may be detectable from transmission from the first wireless device 131 , based on computer simulations of the directional properties of beams caused by propagation geometry in a particular space. At high frequencies, e.g., mmW beams, which may be used in 5G networks, obstacles in the path of the beams may cause beam reflections, beam diffraction and beam shadowing, a strong function of the geometry of the space, e.g., the first cell 121 , where the transmissions of the signal may occur. Ray-tracing simulations may then be used using a computer simulated wireless device, referred to herein simply as a simulated wireless device, to estimate a probability of detection of any of: a) by the first radio network node 1 11 , of the signal received from simulated wireless device, in the set of directions, b) by the simulated wireless device, of beamformed beams transmitted by a simulated radio network node in the set of directions, and c) of both, a) and b). Ray- tracing may be understood as tracing of rays over a detailed map where the rays may interact with objects on the map, e.g., a 3D city map or a 2D building floor layout. These interactions may simulate the characteristics of radio waves at high frequencies, e.g., mmW band, and their interactions with the objects in a map.

According to the foregoing, in this Action 501 , the first network node 101 may obtain a first set of the data. The first set of the data may be understood as simulated data indicating an estimated probability of detection, of a simulated signal received from the simulated wireless device, by the first radio network node 1 1 1 in the set of directions, as estimated by ray-tracing simulations.

In some examples, the first set of the data may be understood as simulated data indicating an estimated probability of detection, by the simulated wireless device, of beamformed beams transmitted by the first radio network node 1 1 1 in a set of directions of transmission of beamformed beams, as estimated by ray-tracing simulations.

In yet other examples, the first set of data may comprise the simulated data based on both the estimated probability of detection by the simulated wireless device, and the estimated probability of detection by the first radio network node 1 1 1.

Obtaining may be understood as determining, calculating, generating, retrieving from a memory, or receiving from another network node in the wireless communications network 100, e.g., the second network node 102.

The probability of detection may be a probability of detecting at least one of: a Time of Arrival (TOA) measurement, and an Uplink Time Difference of Arrival (UTDOA) measurement. The detection may be understood as a successful detection.

The estimated probability of detection may be based on a simulated number of detected directions of the simulated signal received from the simulated wireless device, as based on the ray-tracing simulations. The first set of data may therefore be, for example, a first histogram, or a corresponding set of data, such as a first vector or matrix of directions and respective number of simulated detections. This will be now illustrated with an example.

Example

In order to describe the example, ongoing beam tracking processes at mmW frequencies in a cell is first assumed. The beam tracking may be understood to be, due to beam reflections, beam diffraction and beam shadowing, a strong function of the geometry of the cell, in this case an indoor cell depicted in Figure 6, together with simulated user trajectories. The physical barriers around and within the indoor cell of Figure 6 are illustrated with straight lines. The simulated trajectories of the third wireless device are illustrated with wiggle lines. The striped trajectories represent two examples of individual user trajectories.

The simulations here are first performed using an indoor scenario in which one base station, e.g., a gNB, which is not depicted in Figure 6, is connected with several users.

The purpose is to explain the buildup and origin of the first set of the data, e.g., the histogram information, and to illustrate the strong directional effects created by obstacles at high mmW carrier frequencies.

The carrier frequency in this example is 28 GHz, and it is assumed that the users transmit with equal power in all directions. The base station performs beam tracking for each user, processing up to ten beams at a given point in time. The beams are generated with an 8 x 8 planar array.

New users may turn up in a cell in a variety of ways. The mobile may be turned on in the cell, users may turn up entering the cells around a corner, or by opening a door. That means that some ways to generate initial beam directions may be partly random in terms of the location, while others may appear more regularly depending on the geometry of the cell. A probability map may therefore be built up by introducing a grid, where the initial angle of a first beam scan is added as an event to the first set of the data, in this example, a histogram, on the grid. A grid may be understood as follows. If the space of all possible directions of beam scanning is considered, e.g., azimuth from 0 degree to 360 degrees, the grid may be understood to be over this range of azimuth angles. The grid may also refer to a grid over azimuth and elevation angles.

An example of such a histogram is illustrated in Figure 7, where the x-axis covers directions in [-90 deg, +90 deg], however that range is by no means a necessity. The y axis shows the number of detections. In reference to the geometry of Figure 6, it may be expected that this histogram has a peak roughly at - 15 degrees, since the base station is located at x=0, y=22. Minus 15 (-15) degrees represents the angle where users get into line of sight of the gNB. There may be a background level of the histogram, corresponding to users that turn on the UEs anywhere in the cell. The level may be understood to refer to the bars in the histograms that are above a given threshold. In Figure 7, only a few directions of beam scanning have high occurrence over such threshold.

As may observed in Figure 7, for many directions, the likelihood of a user being found in that direction is very low.

As illustrated in this example, the first network node 101 may obtain the first set of the data, by building a model of the detailed propagation geometry of the signal received from the simulated wireless device, similar to the example depicted in Figure 6, followed by detailed ray-tracing propagation simulation. A detailed propagation geometry may be understood to require a map of the elements that may interact with the radio waves. This may comprise the location of objects that may produce reflections and/or shadowing, e.g., walls, trees, etc. Raytracing, as mention earlier, may be understood as a technique to simulate the characteristics of the radio waves at mmW frequencies. Thus, a map may be generated first, e.g., by the first node 101 , and then a simulation may be performed, e.g., by the first node 101 , of how the radio waves may be expected to propagate on the map. The model may later be used to narrow down the set of directions in which the first radio network node 1 1 1 is capable of beam scanning, in order to estimate the position of the first wireless device 131 .

The first set of the data may also be obtained per site, that is, per radio network node, or based on multi-site, that is, based on the simultaneous detection by more than one site at a time. Since some of the details on the obtaining of the first set of the data may also apply to the obtaining of a second set of data described in the next Action 502, these common further details on the performance of this Action 501 will be provided in the section entitled Phases of the obtaining of the first set of data and/or the second set of the data.

Action 502

The first network node 101 may not only use simulated data to try to estimate the subset of directions of beam scanning in which the first radio network node 1 1 1 may be able to detect the signal received from the first wireless device 131 , but also observed, real data. For example, the one or more third wireless devices 133 may be used as test UEs in the cell of interest, e.g., the first cell 121 for the first radio network node 1 1 1 . The UEs may be moved around the cell in a representative way, and allowed to perform UTDOA positionings, while their reported data is collected.

In this Action 502, the first network node 101 may obtain a second set of the data, e.g., a second histogram, a second matrix, or a second group of histograms, or a second group of matrices. The second set of the data may be understood to comprise historical data indicating an observed probability of detection, of the signal, received from the one or more third wireless devices 133 operating in the wireless communications network 100, in another subset of the set of directions.

In some examples, the second set of the data may be understood to comprise historical data indicating an observed probability of detection, by the first radio network node 1 1 1 , of the signal received from the one or more third wireless devices 133 operating in the wireless communications network 100, in another subset of the set of directions, being above a threshold.

In some examples, the another subset of the set of directions may be the same as the full set of directions. In other examples, the another subset of the set of directions may be understood to be different than the full set of possible directions, since the observed data may be obtained after having initialized the performance of the method with the simulated data obtained in Action 501 , which may be understood to have reduced the full set of directions to another, smaller, subset. That is, the historical data may have been collected based on the full set of directions in which the first radio network node 1 1 1 is capable of transmitting the beamformed beams.

In some examples, the second set of the data may be understood as historical data indicating an estimated probability of detection, by the one or more third wireless devices 133, of beamformed beams transmitted by the first radio network node 1 1 1 in a set of directions of transmission of beamformed beams.

Phases of the obtaining of the first set of data and/or the second set of the data.

The obtaining of either the first set of the data, the second set of the data, or both, may in itself comprise a first phase and a second phase. In the first phase, which is referred to herein as a baseline phase, a first subset of the any of the sets of the data may be obtained without taking advantage of historical data. In a second phase, a second subset of the any of the sets of the data may be obtained using historical data. In the first phase, the scanning performed by the first network node 101 may be, for some examples, a) UE-assisted, and/or b) UE-based. For the UE-assisted scanning, it may be assumed that the one or more second wireless devices 132 used may be able to report back separate TOA detections for each site, e.g., each of the first radio network node 1 1 1 , the second radio network node 1 12, and the third radio network node 1 13. For the UE-based scanning, the scanning may be understood to be performed without signalling of the successful TOA detections per site.

These two phases will now be described in further detail using histograms as an illustrative example of data sets, or data subset. Any of the description provided may be understood to apply to the simulated wireless device or to the one or more third wireless devices 133, unless otherwise specifically noted.

First phase of Action 501 and/or Action 502: Baseline scanning strategies

The following baseline beam scanning strategy may be understood to not take advantage of previous attempts of positioning, e.g., what will be later described as learned histogram information. The baseline beam scanning strategy may be, however, the starting point for the algorithms that analyse the information provided by the baseline strategies and that may exploit the patterns found within such information. In other words, the baseline scanning may be used to provide data for the histograms described herein.

When the first wireless device 131 transmits the signal, e.g., Sounding Reference Signal (SRS), for the purpose of UTDOA positioning, each involved base station, e.g., any of the first radio network node 1 1 1 , the second radio network node 1 12, and the third radio network node 1 13, may measure the impinging signals with its respective AAS system. Each of the first radio network node 1 1 1 , the second radio network node 1 12, and the third radio network node 1 13 may then perform beamspace transformations, and attempt to detect the TOA for each beam direction, e.g., as defined by the applied codebook. Each of the first radio network node 1 1 1 , the second radio network node 1 12, and the third radio network node 1 13 may then detect a number of TOAs, each with different SINR. It may also be the case that no TOA may be detected. The so detected TOAs and the corresponding SINRs may then be signalled on to the first network node 101 , the UTDOA position computation node, with or without further processing in the first radio network node 1 1 1 , the second radio network node 1 12, or the third radio network node 1 13.

2. Second phase of Action 501 and/or Action 502: Obtaining of the sets of the data using prior positionings

To illustrate the features of the obtaining of the sets of the data, histograms will be used here as an example of the sets of data. Obtaining the sets of the data, may therefore comprise generating one or more histograms. The histograms may be first initialized with, e.g., results of the baseline scanning data, and then updated as new data points for the sets of data may be obtained. In other words, embodiments herein allow to incorporate information of successful positioning requests beyond the information collected during the histogram initialization. The first network node 101 may continue to learn histogram information continuously with each new successful positioning request from any of the one or more second wireless devices 132, whenever the positioning information may be reported back to the network. This may be referred to as an“online histogram update”. 2.a) Data sources for online histogram update

When learning histograms to be used for positioning purposes such as the positioning of the first wireless device 131 may be built, the general directional information related to the UE tracking scenario described so far in relation to Action 501 , or to Action 502 may need to be restricted further. More precisely, the histograms may need to be based on directional data related only to previous positionings, or even UTDOA positionings.

Given the above baseline scanning strategy, the following sources of data may be used.

2. a i) The baseline scanning may result in per site directions, for which successful time of arrival detection was obtained. That is, in the first step, the probabilities for a given radio network node may be understood to not depend on the measurement from other radio network nodes. Then, successful time of arrival measurements may be reported by the UE, e.g., any of the second wireless devices 132, without taking into account measurements taken from other radio network nodes. It may be understood that there may be no need to save in the database the fact that the measurements from the first radio network node 1 1 1 are related to the measurement taken by the same UE from the second radio network node 1 12, or from the radio network node 1 13. The first method may therefore be understood to require less information from the any of the second wireless devices 132. 2. a ii) In later position computation steps, a successful position calculation may build on a number of time of arrival detections, each associated with a beam scanning direction of the involved site. In the second step, there may be understood to be a need that at least two radio network nodes report successful measurements from the same wireless device 132. These measurements may need to be taken from the same second wireless device 132 being at the same location. The difference between the two approaches may be understood to start from the moment that the measurements are taken and the data is collected. These beam scanning directions may be understood to provide a more accurate source of information that may be used to update a joint histogram for the detection probability by all involved sites for positioning in a specific cell. This information may serve to discriminate unlikely combination of TOAs in the UTDOA position calculation step, e.g., with Bayesian techniques, or to restrict the joint search space of the first radio network node 1 1 1 , the second radio network node 1 12, and the one or more third radio network nodes 1 13, when they perform beam space detection of TOAs.

2.b) Information sources for initialization of histogram information

When the method is started, it may be understood that no data has been collected and the histograms may not contain any information. At that point of time, the problems with existing methods discussed above remain. In order to improve performance from the start, other sources of prior information may be needed that may then be used to initialize the histograms. To initialize the histograms may be understood as to assign a value to the counters that may be stored in each of the elements in a multidimensional set of data, e.g. histograms, before these histograms may be used for the first time, to determine a subset of directions to scan. The baseline scanning described before may be used to provide information to initialize the histograms. According to embodiments herein, this other prior information may be generated based on one or more of the following sources:

2.b. i) The model of the detailed propagation geometry that may have been constructed as described above in relation to Figure 6, followed by detailed ray-tracing propagation simulations, as explained in relation to Action 501 . Then, simulated UEs, similar to the simulated wireless device, in that environment may be used to initialize the sets of data, e.g., histograms, assuming that UTDOA positionings may be performed. In order to obtain a more robust initialization, the same background value may be added to all histogram bins. Herein, the term bin may be understood to refer to a counter corresponding an event in a histogram. The background value may be understood to allow to assign an initial value, e.g., a count, to the each bin in the histograms. It may be understood as a mathematical way to indicate that all events represented by the histograms are assumed to be equally likely. Such assumptions may be made when no other prior information is available. This background value may need to be selected small enough so that the first radio network node 1 1 1 , the second radio network node 1 12 and any of the third radio network nodes 1 13 do not end up searching the whole space. That is, the space of all possible beam scanning directions.

2.b. ii) The second set of data obtained from some of the one or more second wireless devices 132, or similar test UEs in the cell of interest, may be used to initialize the histograms, moving around the cell in a representative way, and performing UTDOA positionings. In order to obtain a more robust initialization, the same background value may be added to all histogram bins. This background value may need to be selected small enough so that the first radio network node 1 1 1 , the second radio network node 1 12 and the any of the third radio network nodes 1 13 do not end up searching the whole space.

Below, any of the two above, or similar other initialization embodiments, are denoted“histogram initialization” in the non-limiting example algorithms below.

Example 1: UTDOA per site histogram generation

As a pre-requisite for the description of the histogram generation, it may be assumed that K base stations, similar to any of the first radio network node 1 1 1 , the second radio network node 1 12, and the third radio network node 1 13, are involved, and that each base station uses a beamspace / codebook with /_£ directions.

The algorithm for per-site histogram generation for the basic UTDOA scanning strategy may become the following, for each cell the UE is located in:

Histogram initialization

For all transmission/reception times of SRSs For i = I, . . , K For j = l, . . . , N_i

Do beamspace transformation if ( detected TO A in direction j ) HistogramQ. ,j) = Histogram ,j) + 1

End

End The cell identity (ID), and thereby the cell of the UE, may be assumed to be known when UTDOA positioning may be performed. Note that the histograms may be one dimensional, one per site. Note that in case of 2D beamforming, that is, azimuth and elevation, the index j may run over all possible 2D beam directions.

Figure 8 - Figure 12 show how this may turn out with a first set of the data, that is, simulated data, obtained according to Action 501 . The non-limiting examples depicted in Figure 8 - Figure 12, assume four different site locations in the geometry defined in Figure 6.

Figure 8 is a schematic diagram illustrating the site locations and geometry of the mmW simulations. The filled circles indicate the site positions. In each of Figure 9-Figure 12, the x axis represents the azimuth angle in degrees and the y axis represents the number of times a signal has been detected in the corresponding azimuth angle.

Figure 11 is a beam direction histogram for site position x=46, y=1 in Figure 8. Figure 12 is a beam direction histogram for site position x=0, y=21 in Figure 8.

The conclusion that may be drawn from the examples of Figure 8 - Figure 12 is that many directions seem to have very low probability, and may therefore be scanned with low priority, in the background. That is, that other directions may be scanned not as frequently as more used directions. Note that the histograms may easily be transformed to experimental discrete probability density functions, by a normalization of the histogram bins with the total number of detections for each histogram.

Example 2: Multi-site joint histogram generation In the multi-site case, the only source of information may be understood to be provided by the simultaneous detection of TOAs for multiple sites, which may be needed for position calculation.

This may be understood to mean that the final beam scanning direction used to produce the UTDOA position may be used for a joint histogram buildup.

To motivate the advantages of this feature from a physical point of view, the related but not equivalent single site UE tracking case of Figure 6 is revisited. There, the relationship between the angles of a first beam and the angles of secondary beams that were being tracked for the same user were studied. The simulation represented by Figure 6 was used to build up a two dimensional histogram that describes the joint likelihood of the azimuth directions of a first and secondary beam scan. The histogram that may be obtained is depicted in Figure 13 and Figure 14.

Figure 13 is a three-dimensional histogram of the joint likelihood of detection of a signal in a first and second beam scanning direction. In Figure 13, the right horizontal axis depicts azimuth angle of a second beam scan. The left horizontal axis depicts the azimuth angle of a first beam scan, and the vertical axis depicts the probability that the secondary beam scan is at a given angle conditioned to that the azimuth angle of the first beam scan is known. For representation purposes, in the example of Figure 13, the higher the probability, the denser the pattern in the bars represented, and therefore, the darker the color.

Figure 14 depicts the same values of the joint likelihood of a first and second beam scanning direction, in a two-dimensional histogram. For representation purposes, in the example of Figure 14, the higher the probability, the denser the pattern in the bins represented, and therefore, the darker the color.

Again, the buildup procedure may be as follows. The bin of the histogram may be increased by 1 , that is, the histogram counter associated with a respective event is increased by 1 , given, e.g., the registered azimuth angles of beam scan 1 and beam scan 2 of a signal, at each selected time instance of histogram update. It may be noted that, in case a first beam scan direction is available, then the histogram may show that it is a good strategy to search for new beam scanning directions primarily in the directions where the values in the bins of the histogram are large. It may be noted that in the example of Figure 13 and Figure 14, most of the histogram bins have very low values, meaning that only a small part of all beam scanning directions may need to be scanned. The procedure is straightforward to extend to more sites than 2, although that case is not possible to visualize. The algorithm for joint histogram generation for the UTDOA scanning strategy may now be defined. Exhaustive scanning may be understood to refer to a search over the space of all possible beam directions. In this case, the histogram has K dimensions. The updated algorithm may become the following, for each cell the UE, that is, any of the one or more second wireless devices 132, is located in:

Histogram initialization

For all successful positionings of the UE assisted scanning strategy For i = I, . . , K directional) = positioningDirection(i) end

Histogram[direction(l), ... . , direction(K ))

= Histogram(direction 1), . .. . , direction(K)) + 1

End End End

The cell ID, and thereby the cell of the UE, may be assumed to be known when TDOA positioning may need to be performed. It may be noted that in case of 2D beamforming, the direction variables may take values over all possible 2D beam scanning directions.

Action 503

In this Action 503, the first network node 101 determines, out of the set of directions in which the first radio network node 1 1 1 is capable of beam scanning, the subset of directions of transmission of the beamformed beams having the probability of detection above a threshold, of the signal received from the first wireless device 131 operating in the wireless communications network 100. The determining in this Action 503 is based on data obtained from previous attempts of positioning the one or more second wireless devices 132 using at least some of the directions in the set of directions. The data

The data used in the determination of Action 503 may comprise one or more sets of data, e.g., one or more histograms, one or more matrices, etc... Based on any, or both, of Action 501 and Action 502, the first network node 101 may have narrowed down the set of directions in which the first radio network node 1 1 1 is capable of beam scanning, to at least some of these directions. Therefore, the data the determining in this Action 503 is based on may comprise the first set of the data obtained in Action 501 , that is, simulated data, the second set of the data obtained in Action 502, that is, the real observed data, or both. As stated earlier, one or more second wireless devices 132 may the same as the one or more third wireless devices 133, or at least partially overlap with the one or more third wireless devices 133.

The threshold

The threshold may be understood to be configurable. The threshold may be understood to be set based on a probability that a beam direction may be useful for computation of the position of a user, such as the first wireless device 131. This threshold may be considered a first threshold which may indirectly define a“number” of detections over the threshold in the sets of data, e.g., the histograms. The threshold may be designed from a false alarm assumption, or determined from other information, such as a number of characteristics of the power of transmission, the type of radio network node, the type of the one or more third wireless devices 133, the geometric conditions of the first cell 121 , etc... A false alarm may correspond to detection of a signal when there is only noise present. Therefore, the first threshold, may in turn be established based on the probabilities of false alarm detections, that is, a second threshold, which will be discussed later, in relation to Figure 15. Both thresholds may be understood to be related by the number of beam directions to be scanned. Unless otherwise indicated, any reference herein to a threshold may be understood to refer to the first threshold. The subset

The subset of directions of beam scanning having the probability of detection above the threshold, may be understood to be a first subset, which may be referred to herein as the subset to directions to be used in a“priority scan”. That is, the subset of directions having the highest probability of detection, according to the chosen threshold, by the first radio network node 1 1 1 , and which may be used first when attempting to determine the position of the first wireless device 131. The determination of the first subset in this Action 503, may also be understood to result in the determination of a second set of directions out of the set of directions in which the first radio network node 1 1 1 is capable of beam scanning. That is, the remaining set of directions, which are not in the first subset. This second subset of directions may be understood to have the lowest probability of detection, according to the chosen threshold, by the first radio network node 1 1 1 , and may be referred to herein as the subset to directions to be used in a“background scan”, in which all directions may be used, but less frequently. The second subset of directions may, for example, be used when attempting to determine the position of the first wireless device 131 with the first subset does not succeed.

Repetition for each radio network node

So far, the description of the method has been provided in relation to the first radio network node 1 1 1. However, the same actions may be understood to be performed for each of the second radio network node 1 12 and any of one or more the third radio network nodes 1 13. Any of the radio network nodes may be considered“sites”.

The set of directions may be considered a first set of directions, the subset of directions may be considered a first subset of directions, the obtained data may be considered first obtained data, the probability of detection may be considered a first probability of detection, and the previous attempts may be considered first previous attempts. In some embodiments, the determining in Action 503 may further comprise determining one of the following. With respect to the second radio network node 1 12, out of a second set of directions in which a second radio network node 1 12 operating in the wireless communications network 100 may be understood to be capable of beam scanning, a second subset of directions of beam scanning having a second probability of detection of the signal above the threshold, by the second radio network node 1 12. The determining in Action 503 of the second subset may be based on second data obtained from second previous attempts of positioning the one or more second wireless devices 132 using at least some of the directions in the second set of directions.

With respect to the third radio network node 1 13, out of one or more third sets of directions in which one or more third radio network nodes 1 13 operating in the wireless communications network 100 may be understood to be capable of beam scanning, one or more third subsets of directions of beam scanning each having a third probability of detection of the signal above the threshold, by the one or more third radio network nodes 1 13. The determining in Action 503 of the one or more third subsets may be based on one or more third data obtained from one or more third previous attempts of positioning the one or more second wireless devices 132 using at least some of the directions in the one or more third sets of directions. The probability of detection

a) Per site

According to the description provided earlier, in some embodiments, any probability of detection may be a probability of detection by an individual network node, that is, may be per site, as described above. This may be referred to as per-site, or one- dimensional.

In some examples, any probability of detection may be a probability of detection by an individual network node, that is, may be e.g., per site, or per site per cell, or per site per cell per network node’s receive beam, combining information on angle of detection, over time.

b) Multi-site, or over two or more distinct locations

In other embodiments, the set of directions may be the first set of directions, and wherein the second radio network node 1 12 operating in the wireless communications network 100 may be the capable of beam scanning in the second set of directions of beam scanning, the probability of detection above the threshold by the network node 101 may comprise a probability of joint detection, by the first radio network node 1 1 1 and the second radio network node 1 12, in the subset of directions of beam scanning, of the signal in the second subset of directions of beam scanning of the second set of directions of beam scanning. That is, the probability of detection may be multi-site. In such embodiments, the previous attempts of positioning the one or more second wireless devices 132 may have further used at least some of the directions in the second set of directions, e.g., in case the second set has already been narrowed down, for example, by an initialization, as described above, and does not use all the possible directions the second network node is capable of transmitting in.

The joint detection may be understood to also be able to be based on joint detection by the first wireless device 131 of beamformed beams from three of more radio network nodes, e.g., the first radio network node 1 1 1 , the second radio network node 1 12 and the third radio network node 1 13. That is, in some embodiments, wherein the one or more third radio network nodes 1 13 operating in the wireless communications network 100 may be capable of beam scanning in the one or more third sets of directions of beam scanning, the probability of detection above the threshold by the first radio network node 1 1 1 may further comprise a further probability of joint detection, by the first radio network node 1 1 1 and the one or more third radio network nodes 1 13, in the subset of directions of beam scanning, of the signal in the one or more third subsets of directions of beam scanning of the one or more third sets of directions of beam scanning. In such embodiments the previous attempts of positioning the one or more second wireless devices 132 may have further used at least some of the directions in the one or more third sets of directions.

In such“multi-site” embodiments, the probability of detection above the threshold may be comprised in a set of probabilities, e.g., a joint histogram, wherein, each of the probabilities in the set of probabilities may be a respective probability of joint detection, by the first radio network node 1 1 1 and the second radio network node 1 12, of the signal received in a respective first direction and in a respective second direction, being above the threshold. b.1) Simulated data

In some embodiments, the first set of the data may be simulated data indicating an estimated probability of joint detection, by the first radio network node 1 1 1 and the second radio network node 1 12, of the simulated signal from the simulated wireless device, in the first set of directions and in the second set of directions, as estimated by ray-tracing simulations. b.1) Observed data

In some embodiments, the second set of the data may be historical data indicating an observed probability of joint detection, by the first radio network node 1 1 1 and the second radio network node 1 12, of the signal received from the one or more third wireless devices, in another first subset of the first set of directions and in another second subset of the second set directions, being above the threshold.

Action 504

In this Action 504, the first network node 101 initiates providing, to at least one of: the first radio network node 1 1 1 and the second network node 102 operating in the wireless communications network 100, an indication of the determined subset in Action 503.

To initiate providing may be understood as e.g., initiating sending. That is, to provide or send, e.g., via the first link 141 , or to trigger or enable another network node, e.g., the second network node 102, to provide or send, e.g., via the third link 143.

The indication may be, for example, an instruction to scan positioning reference signals in the determined subset e.g.,“perform beamspace transformation corresponding to bin_jkp. Action 505

In some embodiments, the first network node 101 may, in this Action 505, obtain, based on the signal received from the first wireless device 131 , at least one of: a Time of Arrival (TOA) measurement, and an Uplink Time Difference of Arrival (UTDOA) measurement, based on the determined subset of directions or, based on the determined first subset of directions, the determined second subset of directions, and the determined third subset of directions. That the obtaining of the TOA and/or the UTDOA

The obtaining in this Action 505 may be implemented by receiving the information, via the first radio network node 1 1 1 , e.g., via the first link 141 and the fourth link 144, via the second radio network node 1 12, e.g., via the second link 142 and the fifth link 145, and via the third radio network node 1 13, e.g., via the third link 143 and the sixth link 146.

Action 506

In this Action 506, the first network node 101 may determine a position of the first wireless device 131 based on the obtained at least one of: the TOA measurement and the UTDOA measurement, obtained in Action 505.

It may be noted that whenever a positioning attempt may be performed, the then available data, e.g., histogram information, about the likelihood of certain beam scanning direction may be used. At the same time, after the positioning attempt may have been performed, the data, e.g., histograms may be updated with the information learned in the positioning attempt. In that way, the first network node 101 may learn about directions over time. UTDOA multiple hypothesis positioning algorithms using joint histogram

information

Examples of scanning algorithms, according to Action 503, and TDOA positioning, according to Action 505, and Action 506

In the following examples, the numbering on the left hand margin refers to the

Actions described above, as performed by the first network node 101 . Action 504 is depicted on the right side to indicate that the indication is based on the outcome of the determination shown.

In case joint histogram information is available, and multiple TOAs/directions may be reported per site, the restrictions that may be imposed on beam directions by the joint histogram may provide the possibility to discriminate between the alternatives. The normal UTDOA positioning equations may then be solved as usual, however with additions according to any of the following:

i) TOA combinations with corresponding directions may be evaluated in the order of the likelihood of the joint histogram; and

ii) TOA combinations and corresponding directions that have a joint histogram likelihood below a threshold, e.g., the threshold, may be discarded.

Preconditions

As a prerequisite to the combined UTDOA positioning algorithms and scanning strategies that are outlined below, the threshold may first need to be computed. As stated earlier, the purpose of the threshold may be understood to be to enable a selection on if the directions corresponding to a bin may need to be scanned with priority, that is, in a first place given the higher probability of detection of the signal received from the first wireless device 131 , or not. The threshold is denoted th below. All histograms below are also assumed to be normalized by a division by the total number of entries in each histogram.

UOTDOA scanning based on per site, one-dimensional histograms

The algorithm is exemplified for 3 sites, i.e. for K = 3, e.g., the first radio network node 1 1 1 , the second radio network node 1 12, the third radio network node 1 13, denoted below, respectively, as base stations 1 , 2 and 3. The generalization to an arbitrary number of sites may be considered to be straightforward, by addition of more nested loops. This algorithm may be understood to exploit the one-dimensional histograms, built up separately for each site. It may be noted that other examples of the algorithm may exist. % Priority scan...

UE transmitted SRS signals are received in base stations 1, 2 and 3

For j= l,...,Ny

end For 1 = 1. N₃

end

0 5061 Attempt UTDO A position calculation

% Background scan...

For j = 1,...,N₁ bin_x = Histogram(l,j ) 5

Perform beamspace transformation and attempt detection of TO A if successful detection

store and send TO A to position calculation function end

0 end

For k = 1 ,...,N₂ bin₂ = Histogram(2,k )

Perform beamspace transformation and attempt detection of TO A5 if successful detection

store and send TO A to position calculation function end

end

Fori = 1 ,...,N₃

bin₃ = Histogram 3, l )

store and send TO A to position calculation function

end

Attempt UTDOA position calculation

UTDOA scanning based on estimated joint histogram

The algorithm is exemplified for 3 sites, i.e. for K = 3, e.g., the first radio network node 111 , the second radio network node 112, the third radio network node 113, denoted below, respectively, as base stations 1, 2 and 3. The generalization to arbitrary number of sites may be considered to be straightforward, by addition of more nested loops. This algorithm may be understood to exploit the multi-dimensional joint histogram, built up for all sites involved. % Priority scan...

UE transmits SRS

Sites receive joint histogram information

For j = 1,...,N₁

For k = 1 ,...,N₂

Fori = 1 ,...,N₃ m(j,k,l)

503

504 05 Sites attemp to detect TO A

Sites send detected TO As to positioning node

if successful detection in all sites

506 Attempt UTDO A position calculation

stop and exit end end end end end

% Background scan...

For k = 1,...,N₂

Fori = 1 ,...,N₃ bin_jki = Histogram(j,k,l )

Sites perform beam space transformation corresponding to bin_jki Sites attemp to detect TO A

Sites send detected TO As to positioning node

if successful detection in all sites

Attempt UTDOA position calculation

end end

end

As an overall summary of selected aspects of the foregoing, embodiments herein may be understood to enable the generation of sets of data, e.g., histograms, where the sets of data quantify the likelihood of UE presence per beam direction, where the beam directions are with respect to a set of receiving sites, and a specific cell.

Additionally, embodiments herein may also enable adjusting the scanning strategies according to said sets of data, e.g., histograms, with the purpose of performing UTDOA positioning.

Moreover, embodiments herein may also enable determining multiple hypotheses based on computing of an UTDOA based position estimate of a UE.

Based on the foregoing, embodiments herein may also be understood to be related to: i) Generation of histograms, expressing the likelihood of directions between TDOA positioning sites and UEs, said generation being performed using beam scanning direction data from previous TDOA positioning attempts; ii) TDOA positioning, wherein a first set of scanned beams for TDOA positioning may be restricted to beam scanning directions whose likelihood expressed by said histograms, exceeds a threshold ; and iii) TDOA background positioning, wherein the remaining set of beam scanning directions is used for TDOA positioning, when no successful TDOA position may have been determined in step ii).

One or more advantages of embodiments herein may be understood to be that they enable substantial savings in terms of reduced processing and processing time, in comparison with a method that does not use information according to embodiments herein, e.g., from the histograms. As may be appreciated in Figures 9-12, in some histograms, more than 75% of the bins have small values, while some histograms have small values in less than 25% of all bins. Hence, by setting a particular detection threshold, the radio network nodes may be enabled to refrain from beam scanning in many directions of their respective set of directions, e.g., first set, second set and/or third set of directions.

For the scanning strategy based on joint multi-site histograms, the gains appear to be much larger. This is evident from Figure 14 and Figure 15. Already in the illustrated 2- dimensional example, only about 10 % of the bins have large values. This directly translates into a reduction of the scanning processing and latency with a factor of 10. This is an extremely significant system gain. In addition, this gain is expected to increase with the number of involved sites.

Another advantage of embodiments herein is that by selecting the second threshold, the number of bins to search may be correspondingly reduced. To quantify a gain in the reduction of the number bins to search, the probability of false alarm, the second threshold may be considered with power detection. A false alarm may correspond to detection of a signal when there is only noise present. Assuming complex signals, the statistics may be Chi-2 distributed. This gives:

Here, P_/a denotes the false alarm probability, SNR is the signal to noise ratio and

N the number of bins to search. Computing the SNR for P_fa = 0.01 results in Figure 16, which shows the threshold with a line, as a function of the SNR and of the number of bins. Depending on the number of bins to search, the second threshold reduction may reach 1.5 dB for a reduction of the search space of a factor of 10.

Figure 15 is a diagram depicting a false alarm detection threshold, also named herein a second threshold, as a function of the dimension of the search space.

Figure 16 depicts two different examples in panels a) and b), respectively, of the arrangement that the first network node 101 may comprise to perform the method actions described above in relation to Figure 5, as e.g., further detailed in any of Figure 6-Figure 15. In some embodiments, the first network node 101 may comprise the following arrangement depicted in Figure 16a. The first network node 101 is configured to handle directions of receiver beam scanning of an antenna array configured to be in the first radio network node 1 1 1. The first network node 101 and the first radio network node 1 1 1 are further configured to operate in the wireless communications network 100.

Several embodiments are comprised herein. Components from one embodiment may be tacitly assumed to be present in another embodiment and it will be obvious to a person skilled in the art how those components may be used in the other exemplary embodiments. The detailed description of some of the following corresponds to the same references provided above, in relation to the actions described for the first network node 101 , and will thus not be repeated here. For example, the first network node 101 may be an E-SMLC and the first radio network node 1 1 1 may be a gNB.

In Figure 16, optional modules are indicated with dashed boxes.

The first network node 101 is configured to, e.g. by means of a determining module 1601 within the first network node 101 configured to, determine, out of the set of directions in which the first radio network node 1 1 1 is configured to be capable of beam scanning, the subset of directions of beam scanning configured to have the probability of detection above the threshold, of a signal configured to be received from the first wireless device 131 configured to operate in the wireless communications network 100. To determine is configured to be based on the data configured to be obtained from the previous attempts of positioning the one or more second wireless devices 132 using at least some of the directions in the set of directions.

The first network node 101 is further configured to, e.g. by means of an initiating module 1602 within the first network node 101 configured to, initiate providing, to at least one of: the first radio network node 1 1 1 and the second network node 102 configured to operate in the wireless communications network 100, the indication of the subset configured to be determined.

In some embodiments, the probability of detection may be configured to be the probability of performing at least one of: the TOA measurement, and the UTDOA measurement.

The first network node 101 may be further configured to e.g. by means of an obtaining module 1603 within the first network node 101 configured to, obtain the first set of the data, the first set of the data being configured to be the simulated data configured to indicate the estimated probability of detection, of a simulated signal configured to be received from the simulated wireless device, by the first radio network node 1 1 1 in the set of directions, as configured to be estimated by the ray-tracing simulations. In some embodiments, wherein the subset of directions is a first subset, the first network node 101 may be further configured to, e.g. by means of the obtaining module 1603 within the first network node 101 configured to, obtain the second set of the data. The second set of the data may be configured to be historical data configured to indicate the observed probability of detection, of the signal, configured to be received from the one or more third wireless devices 133 configured to operate in the wireless communications network 100, in the another subset of the set of directions.

In some examples, the second set of the data may be configured to be historical data configured to indicate the observed probability of detection, by the one or more third wireless devices 133 configured to operate in the wireless communications network 100, of the beamformed beams in the another subset of the set of directions, being above the threshold.

In some embodiments, wherein the set of directions is a first set of directions, the subset of directions is a first subset of directions, the obtained data is first obtained data, the probability of detection is a first probability of detection, and the previous attempts are first previous attempts, to determine may be configured to further comprise determining: a. out of the second set of directions in which a second radio network node 1 12 configured to operate in the wireless communications network 100 is configured to be capable of beam scanning, the second subset of directions of beam scanning being configured to have a second probability of detection of the signal above the threshold, by the second radio network node 1 12, the determining of the second subset being configured to be based on the second data configured to be obtained from the second previous attempts of positioning the one or more second wireless devices 132 configured to use at least some of the directions in the second set of directions; and

b. out of the third set of directions in which a third radio network node 1 13

configured to operate in the wireless communications network 100 is configured to be capable of beam scanning, the third subset of directions of beam scanning being configured to have the third probability of detection of the signal above the threshold, by the third radio network node 1 13, the determining of the third subset being configured to be based on third data configured to be obtained from third previous attempts of positioning the one or more second wireless devices 132 configured to use at least some of the directions in the third set of directions. In some embodiments, the first network node 101 may be further configured to, e.g. by means of the obtaining module 1603 within the first network node 101 , configured to obtain, from the first wireless device 131 configured to operate in the wireless

communications network 100 at least one of: the TOA measurement, and the UTDOA measurement, based on the first subset of directions configured to be determined, the second subset of directions configured to be determined and the third subset of directions configured to be determined.

The first network node 101 may be further configured to, e.g. by means of the determining module 1601 within the first network node 101 configured to, determine the position of the first wireless device 131 based on the configured to be obtained at least one of: the TOA measurement, and the UTDOA measurement.

In some embodiments, any probability of detection may be configured to be the probability of detection by an individual network node.

In some embodiments, the set of directions is a first set of directions, and the second radio network node 1 12 configured to operate in the wireless communications network 100 is configured to be capable of beam scanning in the second set of directions of beam scanning, the probability of detection above the threshold by the first network node 101 may be configured to comprise the probability of joint detection, by the first radio network node 1 1 1 and the second radio network node 1 12, in the subset of directions of beam scanning, of the signal in the second subset of directions of beam scanning of the second set of directions of beam scanning, and the previous attempts of positioning the one or more second wireless devices 132 may be configured to have further used at least some of the directions in the second set of directions.

In some embodiments, the probability of detection above the threshold may be configured to be comprised in a set of probabilities, each of the probabilities in the set of probabilities being the respective fourth probability of joint detection, by the first radio network node 1 1 1 and the second radio network node 1 12, of the signal configured to be received in the respective first direction and in the respective second direction, being above the threshold.

In some embodiments, the first set of the data may be configured to be simulated data configured to indicate the estimated probability of joint detection, by the first radio network node 1 1 1 and the second radio network node 1 12, of the simulated signal from the simulated wireless device, in the first set of directions and in the second set of directions, as configured to be estimated by the ray-tracing simulations. In some embodiments, the second set of the data may be configured to be historical data configured to indicate the observed probability of joint detection by the first radio network node 1 1 1 and the second radio network node 1 12, of the signal received from the one or more third wireless devices 133, in the another first subset of the first set of directions and in the another second subset of the second set directions, being above the threshold.

In some embodiments, wherein the third radio network node 1 13 configured to operate in the wireless communications network 100 is configured to be capable of beam scanning in the third set of directions of beam scanning, and wherein the probability of detection above the threshold by the first radio network node 1 1 1 is configured to further comprise the further probability of joint detection, by the first radio network node 1 1 1 and the third radio network node 1 13, in the subset of directions of beam scanning, of the signal in the third subset of directions of beam scanning of the third set of directions of beam scanning, the previous attempts of positioning the one or more second wireless devices 132 may be configured to have further used at least some of the directions in the third set of directions. In some of these embodiments, the first network node 101 may be further configured to, e.g. by means of the obtaining module 1603 within the first network node 101 configured to, obtain, from the first wireless device 131 configured to operate in the wireless communications network 100 at least one of: the UTDOA measurement, and the TOA measurement, based on the subset of directions configured to be determined. The first network node 101 may be further configured to, e.g. by means of the determining module 1601 within the first network node 101 configured to, determine the position of the first wireless device 131 based on the configured to be obtained at least one of: the UTDOA measurement, and the TOA measurement.

Other modules 1604 may be comprised in the first network node 101.

The embodiments herein in the first network node 101 may be implemented through one or more processors, such as a processor 1605 in the first network node 101 depicted in Figure 16a, together with computer program code for performing the functions and actions of the embodiments herein. A processor, as used herein, may be understood to be a hardware component. The program code mentioned above may also be provided as a computer program product, for instance in the form of a data carrier carrying computer program code for performing the embodiments herein when being loaded into the first network node 101 . One such carrier may be in the form of a CD ROM disc. It is however feasible with other data carriers such as a memory stick. The computer program code may furthermore be provided as pure program code on a server and downloaded to the first network node 101 .

The first network node 101 may further comprise a memory 1606 comprising one or more memory units. The memory 1606 is arranged to be used to store obtained information, store data, configurations, schedulings, and applications etc. to perform the methods herein when being executed in the first network node 101 .

In some embodiments, the first network node 101 may receive information from, e.g., the first radio network node 1 1 1 , the second radio network node 1 12, the third radio network node 1 13, or the second network node 102, through a receiving port 1607. In some embodiments, the receiving port 1607 may be, for example, connected to one or more antennas in first network node 101 . In other embodiments, the first network node 101 may receive information from another structure in the wireless communications network 100 through the receiving port 1607. Since the receiving port 1607 may be in communication with the processor 1605, the receiving port 1607 may then send the received information to the processor 1605. The receiving port 1607 may also be configured to receive other information.

The processor 1605 in the first network node 101 may be further configured to transmit or send information to e.g., the first radio network node 1 1 1 , the second radio network node 1 12, the third radio network node 1 13, or the second network node 102, or another structure in the wireless communications network 100, through a sending port 1608, which may be in communication with the processor 1605, and the memory 1606.

Those skilled in the art will also appreciate that the determining module 1601 , the initiating module 1602, the obtaining module 1603, and the other modules 1604 described above may refer to a combination of analog and digital modules, and/or one or more processors configured with software and/or firmware, e.g., stored in memory, that, when executed by the one or more processors such as the processor 1605, perform as described above. One or more of these processors, as well as the other digital hardware, may be included in a single Application-Specific Integrated Circuit (ASIC), or several processors and various digital hardware may be distributed among several separate components, whether individually packaged or assembled into a System-on-a-Chip (SoC).

Also, in some embodiments, the different modules 1601 -1604 described above may be implemented as one or more applications running on one or more processors such as the processor 1605.

Thus, the methods according to the embodiments described herein for the first network node 101 may be respectively implemented by means of a computer program 1609 product, comprising instructions, i.e., software code portions, which, when executed on at least one processor 1605, cause the at least one processor 1605 to carry out the actions described herein, as performed by the first network node 101. The computer program 1609 product may be stored on a computer-readable storage medium 1610. The computer-readable storage medium 1610, having stored thereon the computer program 1609, may comprise instructions which, when executed on at least one processor 1605, cause the at least one processor 1605 to carry out the actions described herein, as performed by the first network node 101. In some embodiments, the computer- readable storage medium 1610 may be a non-transitory computer-readable storage medium, such as a CD ROM disc, or a memory stick. In other embodiments, the computer program 1609 product may be stored on a carrier containing the computer program 1609 just described, wherein the carrier is one of an electronic signal, optical signal, radio signal, or the computer-readable storage medium 1610, as described above.

The first network node 101 may comprise a communication interface configured to facilitate communications between the first network node 101 and other nodes or devices, e.g., the first radio network node 1 1 1 , the second radio network node 1 12, the third radio network node 1 13, or the second network node 102. The interface may, for example, include a transceiver configured to transmit and receive radio signals over an air interface in accordance with a suitable standard.

In other embodiments, the first network node 101 may comprise the following arrangement depicted in Figure 16b. The first network node 101 may comprise a processing circuitry 1605, e.g., one or more processors such as the processor 1605, in the first network node 101 and the memory 1606. The first network node 101 may also comprise a radio circuitry 1611 , which may comprise e.g., the receiving port 1607 and the sending port 1608. The processing circuitry 1605 may be configured to, or operable to, perform the method actions according to Figure 5, and any of Figure 6 - Figure 15, in a similar manner as that described in relation to Figure 16a. The radio circuitry 161 1 may be configured to set up and maintain at least a wireless connection with the first node 101. Circuitry may be understood herein as a hardware component.

Hence, embodiments herein also relate to the first network node 101 operative to handle directions of receiver beam scanning of an antenna array in a first radio network node 1 1 1 , the first network node 101 being operative to operate in the wireless communications network 100. The first network node 101 may comprise the processing circuitry 1605 and the memory 1606, said memory 1606 containing instructions executable by said processing circuitry 1605, whereby the first network node 101 is further operative to perform the actions described herein in relation to the first network node 101 , e.g., in Figure 5, and any of Figure 6 - Figure 15.

Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and/or is implied from the context in which it is used. All references to a/an/the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any methods disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and/or where it is implicit that a step must follow or precede another step. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever appropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa. Other objectives, features and advantages of the enclosed embodiments will be apparent from the following description.

Claims

CLAIMS:

1. A method, performed by a first network node (101), for handling directions of receiver beam scanning of an antenna array in a first radio network node (1 1 1), the first network node (101) and the first radio network node (1 1 1) operating in a wireless communications network (100), the method comprising:

- determining (503), out of a set of directions in which the first radio network node (1 1 1) is capable of beam scanning, a subset of directions of beam scanning having a probability of detection above a threshold, of a signal received from a first wireless device (131) operating in the wireless communications network (100), the determining (503) being based on data obtained from previous attempts of positioning one or more second wireless devices (132) using at least some of the directions in the set of directions, and - initiating (504) providing, to at least one of: the first radio network node (1 1 1) and a second network node (102) operating in the wireless communications network (100), an indication of the determined subset.

2. The method according to claim 1 , wherein the probability of detection is a

probability of detecting at least one of: a Time of Arrival, TOA, measurement, and an Uplink Time Difference of Arrival, UTDOA, measurement.

3. The method according to any of claims 1 -2, wherein the method further comprises:

- obtaining (501) a first set of the data, the first set of the data being simulated data indicating an estimated probability of detection of a simulated signal received from a simulated wireless device, by the first radio network node (1 1 1), in the set of directions, as estimated by ray-tracing simulations.

4. The method according to any of claims 1 -3, wherein the subset of directions is a first subset, and wherein the method further comprises:

- obtaining (502) a second set of the data, the second set of the data being historical data indicating an observed probability of detection of the signal, received from one or more third wireless devices (133) operating in the wireless communications network (100), in another subset of the set of directions.

5. The method according to any of claims 1 -4, wherein the set of directions is a first set of directions, the subset of directions is a first subset of directions, the obtained data is first obtained data, the probability of detection is a first probability of detection, and the previous attempts are first previous attempts, and wherein the determining (503) further comprises determining (503):

a. out of a second set of directions in which a second radio network node (1 12) operating in the wireless communications network (100) is capable of beam scanning, a second subset of directions of beam scanning having a second probability of detection of the signal above the threshold, by the second radio network node (1 12), the determining (503) of the second subset being based on second data obtained from second previous attempts of positioning the one or more second wireless devices (132) using at least some of the directions in the second set of directions; and b. out of one or more third sets of directions in which one or more third radio network nodes (1 13) operating in the wireless communications network

(100) are capable of beam scanning, one or more third subsets of directions of beam scanning each having a third probability of detection of the signal above the threshold, by the one or more third radio network nodes (1 13), the determining (503) of the one or more third subsets being based on one or more third data obtained from one or more third previous attempts of positioning the one or more second wireless devices (132) using at least some of the directions in the one or more third sets of directions. 6. The method according to claim 5, wherein the method further comprises:

- obtaining (505), based on the signal received from the first wireless device (131) at least one of: a Time of Arrival, TOA, measurement, and an Uplink Time Difference of Arrival, UTDOA, measurement, based on the determined first subset of directions, the determined second subset of directions and the determined third subset of directions, and

- determining (506) a position of the first wireless device (131) based on the obtained at least one of: the TOA measurement, and the UTDOA

measurement. 7. The method according to any of claims 1 -6, wherein any probability of detection is a probability of detection by an individual network node.

8. The method according to any of claims 1 -4, wherein the set of directions is a first set of directions, and wherein a second radio network node (1 12) operating in the wireless communications network (100) is capable of beam scanning in a second set of directions of beam scanning, and wherein the probability of detection above the threshold by the first network node (101) comprises a probability of joint detection, by the first radio network node (1 1 1) and the second radio network node (1 12), in the subset of directions of beam scanning, of the signal in a second subset of directions of beam scanning of the second set of directions of beam scanning, and wherein the previous attempts of positioning the one or more second wireless devices (132) have further used at least some of the directions in the second set of directions.

9. The method according to claim 8, wherein the probability of detection above the threshold is comprised in a set of probabilities, each of the probabilities in the set of probabilities being a respective probability of joint detection, by the first radio network node (1 1 1) and the second radio network node (1 12), of the signal received in a respective first direction and a in a respective second direction, being above the threshold.

10. The method according to claims 3 and any of claims 8-9, wherein the first set of the data are simulated data indicating an estimated probability of joint detection, by the first radio network node (1 1 1) and the second radio network node (1 12), of the simulated signal from the simulated wireless device, in the first set of directions and in the second set of directions, as estimated by ray-tracing simulations.

1 1 . The method according to claim 4 any of claims 8-10, wherein the second set of the data are historical data indicating an observed probability of joint detection by the first radio network node (1 1 1) and the second radio network node (1 12), of the signal received from the one or more third wireless devices (133), in another first subset of the first set of directions and in another second subset of the second set directions, being above the threshold. 12. The method according to any of claims 8-1 1 , wherein one or more third radio

network nodes (1 13) operating in the wireless communications network (100) are capable of beam scanning in one or more third sets of directions of beam scanning, and wherein the probability of detection above the threshold by the first radio network node (1 1 1) further comprises a further probability of joint detection, by the first radio network node (1 1 1) and the one or more third radio network nodes (1 13), in the subset of directions of beam scanning, of the signal in a one or more third subsets of directions of beam scanning of the one or more third sets of directions of beam scanning, and wherein the previous attempts of positioning the one or more second wireless devices (132) have further used at least some of the directions in the one or more third sets of directions, and wherein the method further comprises:

- obtaining (505), based on the signal received from the first wireless device

(131), at least one of: an Uplink Time Difference of Arrival, UTDOA, measurement, and a Time of Arrival, TOA, measurement, based on the determined subset of directions, and

- determining (506) a position of the first wireless device (131) based on the obtained at least one of: the UTDOA, measurement, and the TOA

measurement.

13. A first network node (101) configured to handle directions of receiver beam

scanning of an antenna array configured to be in a first radio network node (1 1 1), the first network node (101) and the first radio network node (1 1 1) being configured to operate in a wireless communications network (100), the first network node (101) being further configured to:

- determine, out of a set of directions in which the first radio network node (1 1 1) is configured to be capable of beam scanning, a subset of directions of beam scanning configured to have a probability of detection above a threshold, of a signal configured to be received from a first wireless device (131) configured to operate in the wireless communications network (100), wherein to determine is configured to be based on data configured to be obtained from previous attempts of positioning one or more second wireless devices (132) using at least some of the directions in the set of directions, and

- initiate providing, to at least one of: the first radio network node (1 1 1) and a second network node (102) configured to operate in the wireless

communications network (100), an indication of the subset configured to be determined.

14. The first network node (101) according to claim 13, wherein the probability of detection is configured to be a probability of performing at least one of: a Time of Arrival, TOA, measurement, and an Uplink Time Difference of Arrival, UTDOA, measurement.

15. The first network node (101) according to any of claims 13-14, wherein the first network node (101) is further configured to:

- obtain a first set of the data, the first set of the data being configured to be simulated data configured to indicate an estimated probability of detection of a simulated signal configured to be received from a simulated wireless device, by the first radio network node (1 1 1), in the set of directions, as configured to be estimated by ray-tracing simulations.

16. The first network node (101) according to any of claims 13-15, wherein the subset of directions is a first subset, and wherein the first network node (101) is further configured to:

- obtain a second set of the data, the second set of the data being configured to be historical data configured to indicate an observed probability of detection of the signal, configured to be received from one or more third wireless devices (133) configured to operate in the wireless communications network (100), in another subset of the set of directions.

17. The first network node (101) according to any of claims 13-16, wherein the set of directions is a first set of directions, the subset of directions is a first subset of directions, the obtained data is first obtained data, the probability of detection is a first probability of detection, and the previous attempts are first previous attempts, and wherein to determine is configured to further comprise

determining:

a. out of a second set of directions in which a second radio network node (1 12) configured to operate in the wireless communications network (100) is configured to be capable of beam scanning, a second subset of directions of beam scanning being configured to have a second probability of detection of the signal above the threshold, by the second radio network node (1 12), the determining of the second subset being configured to be based on second data configured to be obtained from second previous attempts of positioning the one or more second wireless devices (132) configured to use at least some of the directions in the second set of directions; and

b. out of a third set of directions in which a third radio network node (1 13) configured to operate in the wireless communications network (100) is configured to be capable of beam scanning, a third subset of directions of beam scanning being configured to have a third probability of detection of the signal above the threshold, by the third radio network node (1 13), the determining of the third subset being configured to be based on third data configured to be obtained from third previous attempts of positioning the one or more second wireless devices (132) configured to use at least some of the directions in the third set of directions.

18. The first network node (101) according to claim 17, wherein the first network node (101) is further configured to:

- obtain, from the first wireless device (131) configured to operate in the wireless communications network (100) at least one of: a Time of Arrival,

TOA, measurement, and an Uplink Time Difference of Arrival, UTDOA, measurement, based on the first subset of directions configured to be determined, the second subset of directions configured to be determined and the third subset of directions configured to be determined, and

- determine a position of the first wireless device (131) based on the configured to be obtained at least one of: the TOA measurement, and the UTDOA measurement. 19. The first network node (101) according to any of claims 13-18, wherein any

probability of detection is configured to be a probability of detection by an individual network node.

20. The first network node (101) according to any of claims 13-19, wherein the set of directions is a first set of directions, and wherein a second radio network node

(1 12) configured to operate in the wireless communications network (100) is configured to be capable of beam scanning in a second set of directions of beam scanning, and wherein the probability of detection above the threshold by the first network node (101) is configured to comprise a probability of joint detection, by the first radio network node (1 1 1) and the second radio network node (1 12), in the subset of directions of beam scanning, of the signal in a second subset of directions of beam scanning of the second set of directions of beam scanning, and wherein the previous attempts of positioning the one or more second wireless devices (132) are configured to have further used at least some of the directions in the second set of directions.

21. The first network node (101) according to claim 20, wherein the probability of detection above the threshold is configured to be comprised in a set of

probabilities, each of the probabilities in the set of probabilities being a respective fourth probability of joint detection, by the first radio network node (1 1 1) and the second radio network node (1 12), of the signal configured to be received in a respective first direction and in a respective second direction, being above the threshold.

22. The first network node (101) according to claims 15 and any of claims 20-21 , wherein the first set of the data are configured to be simulated data configured to indicate an estimated probability of joint detection, by the first radio network node (1 1 1) and the second radio network node (1 12), of the simulated signal from the simulated wireless device, in the first set of directions and in the second set of directions, as configured to be estimated by ray-tracing simulations.

23. The first network node (101) according to claim 16 any of claims 20-22, wherein the second set of the data are configured to be historical data configured to indicate an observed probability of joint detection by the first radio network node (11 1) and the second radio network node (1 12), of the signal received from the one or more third wireless devices (133), in another first subset of the first set of directions and in another second subset of the second set directions, being above the threshold.

24. The first network node (101) according to any of claims 20-23, wherein a third radio network node (1 13) configured to operate in the wireless communications network (100) is configured to be capable of beam scanning in a third set of directions of beam scanning, and wherein the probability of detection above the threshold by the first radio network node (1 1 1) is configured to further comprise a further probability of joint detection, by the first radio network node (1 1 1) and the third radio network node (1 13), in the subset of directions of beam scanning, of the signal in a third subset of directions of beam scanning of the third set of directions of beam scanning, and wherein the previous attempts of positioning the one or more second wireless devices (132) are configured to have further used at least some of the directions in the third set of directions, and wherein the first network node (101) is further configured to:

- obtain, from the first wireless device (131) configured to operate in the wireless communications network (100) at least one of: an Uplink Time

5 Difference of Arrival, UTDOA, measurement, and a Time of Arrival, TOA, measurement, based on the subset of directions configured to be determined, and

- determine a position of the first wireless device (131) based on the configured to be obtained at least one of: the UTDOA measurement, and the TOA o measurement. 5