Method for network optimization of cellular networks

Abstract

The present invention relates to a method for a first base station operating with a cellular network, the first base station covering a first cell area and being connectively coupled to a second base station supporting beamforming and covering a second cell area, wherein a plurality of user equipment are located in the first cell area, the method comprising the following steps: - sending a message representing an instruction to perform at least one automatic neighbor relation measurement to at least one user equipment among the plurality of user equipment located in the first cell area, - receiving at least one automatic neighbor relation message from the at least one user equipment, - omitting the at least one user equipment from further consideration for a further automatic neighbor relation evaluation in case the automatic neighbor relation message indicates that the user equipment is located outside the second cell area.

Description

Technical Field

[0001] The present invention relates to a method for a base station operating with a cellular network. The present invention also relates to a base station using said method. Background Art

[0002] In the field of wireless cellular communications, it is a well-established procedure that a base station of a cellular network maintains a neighbor list indicating which base stations are in the vicinity of the base station, which means in particular to which base stations a handover of a user equipment may occur. Although this neighbor list was originally configured by the network operator, in later generations of cellular technology standards a procedure called Self-Organizing Networks (SON) was introduced. This method consists in modifying the neighbor list with the help of signals from a user equipment operating with a base station (e.g. when camped on a base station or when in connected mode), measuring neighbor cell signals and providing decodable information from all other base stations. This results in a significant reduction in maintenance work and the neighbor list is quickly updated even when new base stations are installed on site. This method is also known as Automatic Neighbor Relation (ANR), correspondingly when performed in idle it is known as MDT (Minimization of Drive Tests), which consists in reporting all cells on which the user equipment camps once it has reconnected to a base station of said cellular network.

[0003] However, this approach is based on the concept that the area which the cellular network should cover is now more or less completely covered with the cell areas of the corresponding base stations and that all base stations perform essentially the same tasks in the same radio access network.

[0004] These claims no longer apply to 5G (New Radio, NR) in general, and in particular not to any 5G deployment above 6 GHz, i.e. in Frequency Range 2 (FR2).

[0005] FR2 is currently considered for indoors, hotspots or areas with a demand for high data throughput. Here the situation will be that base stations in the lower frequency area are available and are coverage-oriented, while base stations in the higher frequency area are more throughput-oriented, but do not permanently cover a larger area or cells in that range from a larger continuous coverage area so far, instead they usually use beamforming and cover a small area with several beams. In the currently defined non-standalone (NSA) 5G rollout, the first type of base station may even support 4G in this way.

[0006] For the first type of base stations, i.e. those in the low frequency range, also known as FR1, they can rely on well-known concepts developed for LTE, such as MDT (Minimization of Drive Tests), where the user equipment reports all the cell IDs on which the user equipment is camped at the same time at its next connection establishment. Or more such connection-oriented approaches, where a user equipment in dedicated mode receives dedicated measurement instructions for the intended neighbor cells to establish neighbor cell relations. These concepts are now also standardized for NR.

[0007] However, these methods are not sufficient for 5G deployed in FR2, as common ANR / SON methods are not feasible for this type of base station architecture. Since the low frequency base station maintains the registration of user equipment and then switches to the higher frequency base station for high throughput communication, it is necessary to receive measurements of the higher frequency neighbor base stations.

[0008] Therefore, when moving in idle, the user equipment will not always change its serving base station just for MDT reporting, because the user equipment will always need to hop back and forth, because continuous coverage is not guaranteed in FR2. In addition, base stations in FR2 cover their area via multiple beams, so for those base stations, it is important to evaluate which beams really attract or cover the users and which beams do not attract or cover the users.

[0009] Therefore, a method is needed to handle ANR messages and further improve the coverage of user equipment in FR2. Therefore, the object of the present invention is to overcome the mentioned disadvantages and propose a solution for improving the handling of Automatic Neighbor Relation Management of base stations in new scenarios of New Radio, respectively for higher frequency ranges (FR2).

[0010] Therefore, further alternative and advantageous solutions would be desirable in the art. Summary of the invention

[0011] To this end, according to a first aspect of the present invention, a method for a first base station according to claim 1 is proposed. According to a second aspect of the present invention, a base station according to claim 9 is further proposed.

[0012] According to a first aspect of the present invention, a method for a first base station operating with a cellular network is provided, the first base station covering a first cell area and being connectively coupled to a second base station supporting beamforming and covering a second cell area, wherein a plurality of user equipments are located in the first cell area, the method comprising the following steps:

[0013] - sending a message representing an instruction to perform at least one automatic neighbor relation measurement to at least one user equipment among a plurality of user equipments located in the first cell area,

[0014] - receiving at least one automatic neighbor relation message from said at least one user equipment,

[0015] - in case the automatic neighbor relation message indicates that the user equipment is located outside a second cell area, omitting the at least one user equipment from further consideration for a further automatic neighbor relation evaluation.

[0016] A first aspect of the invention relates to a first base station operating with a cellular network. The cellular network is a network supporting at least 4G and 5G technology standards.

[0017] The first base station is a base station designated for coverage-oriented services in a cell area. This means that the purpose of multiple base stations of the first base station type belonging to a cellular network is to seamlessly cover the coverage area of ​​the cellular network. Of course, coverage holes may exist, but this does not change the overall approach.

[0018] Such base stations of the first base station type are 4G base stations in the non-standalone (NSA) approach exhibited by 5G. For the later stages of standalone operation, the first base station is a 5G or higher base station of the first type designated to cover the entire cell area. Such base stations (gNB) are also called anchor cells or wide area base stations. Typically, they operate in a frequency range that is part of FR1, preferably even below 2GHz, which allows to perform full coverage with a reasonable number of base stations.

[0019] The first base station is communicatively connected to a second base station, which is supporting beamforming and is covering a second cell area. Beamforming is a known technology applied in NR for normal operation as a MIMO technology for overcoming increased MCL (minimum coupling loss) especially in higher frequency regions. Beam management of NR is studied in the context of Rel.14, and the most important beam management functionality is described in Section 6.1.6.1 Beam Management, such as TR38.802.

[0020] In NR, beam management is defined as follows:

[0021] - Beam management: A set of L1 / L2 procedures to acquire and maintain a set (one or more) of TRPs and / or UE beams that can be used for DL ​​and UL transmission / reception, which includes at least the following aspects:

[0022] - Beam determination: for (one or more) TRPs or UE to select its own (one or more) Tx / Rx beams;

[0023] - Beam Measurement: for (one or more) TRPs or UEs to measure the characteristics of the received beamformed signal;

[0024] - Beam reporting: information for the UE to report (one or more) beamformed signals based on beam measurements;

[0025] - Beam scanning: An operation covering a spatial area in which beams are transmitted and / or received in a predetermined manner during a time interval. It also includes measurements related to beams in the DL, which can be reported in the UL in the same or another beam. However, the measurements and the relationship between the UL / DL beams and the applied techniques are not the subject of the present invention, but it is considered that such mechanisms are known and can be applied here within the techniques. It is also known that a user equipment can measure not only one beam, but also neighbor beams. However, when only one beam is reported, the strongest beam, or no beam, or a group of beams above a certain level, or general beams above a certain level are reported in addition to the strongest beam, the techniques mentioned below can be applied. The essence is whether a user equipment in the potential coverage area, i.e. the second cell area, instantaneously receives at least one beam suitable for communication, or whether this can only be achieved after further adjustment of the beam.

[0026] In this sense, coverage does not mean that in every location of the second cell area, a connection link of the user equipment to the second base station is possible permanently or even most of the time. This is a throughput-oriented base station and it supports 5G or higher technical standards for the high frequency range (FR2).

[0027] The 5G technical standard is designed in such a way that a base station of a first base station type is available for user equipment to camp on, while - in particular depending on the requested throughput - a switch, a corresponding connection setup for switching, or a multi-carrier setup including said base stations of a second base station type is required.

[0028] This also requires that the first base station has accurate knowledge about which parts of the second cell area are covered by at least one second base station in the vicinity, in particular resident user equipment that may want to set up a connection have an opportunity to do so due to the current coverage.

[0029] This is where the present invention comes into play.

[0030] The general concept of automatic neighbor relation messages is known, but adaptation to this new scenario is required.

[0031] Therefore, according to a first aspect of the present invention, it is proposed that the first base station sends a message representing an instruction to perform at least one automatic neighbour relation measurement to all or a subset of those user equipments currently located in the first cell area.

[0032] In reality, these user equipments are camping on the first base station, so they are known at that time - if this should be required for sending the message.

[0033] Using the ANR message, the first base station should trigger such automatic neighbor relation measurement. Such automatic neighbor relation measurement at least includes receiving signals and measuring signal strength for one or more base stations. In particular, if necessary, it can include decoding the broadcast of system information of one or more neighbor base stations.

[0034] It is also contemplated that the first base station indicates with the sent message which base station or base stations the measurements should be carried out from.

[0035] Preferably, the user equipment carries out such measurements and, on the basis of the measurements, performs an assessment which indicates, inter alia, whether it will be strong enough to operate with it.

[0036] Ideally, such measurements and evaluations need to be done by all user equipments in the area, not just those currently connected. This already leads to an additional problem to be solved, namely that user equipments from different states may equally be involved in the method, even if this means that several of them also perform a state change.

[0037] Hence, the first base station receives at least one Automatic Neighbor Relation message from said user equipment.Preferably, it is a plurality of messages from all user equipments to which the first base station sends messages for instructing ANR measurements.

[0038] Such messages represent automatic neighbor relation measurements from user equipment, and in particular evaluations of such measurements.

[0039] The first base station evaluates the received ANR message for figuring out whether the sending user equipment is located outside the second cell area. The second cell area is a cell area that may be covered by the second base station, but this does not necessarily mean that the user equipment receives signals from the second base station.

[0040] In case the user equipment is outside the second cell area, the next request of the user equipment from ANR measurement for the second base station is omitted. This is particularly advantageous for such user equipment in stationary operation and it reduces the power consumption for carrying out measurements and sending ANR messages (completely in vain).

[0041] However, a step of taking into account said at least one user equipment in case the automatic neighbor relation message indicates that said user equipment is located inside the second cell area is proposed.

[0042] For further processing of the automatic neighbor relation evaluation, those user equipments indicating that they are located inside the second cell area are evaluated.Thus, for further ANR messages, only those user equipments found inside the second cell area of ​​the second base station are instructed to perform further ANR measurements after a certain period of time.

[0043] This separation requires figuring out whether the user equipment is located inside the second cell area. This is possible through several different operations or submitted data.

[0044] Preferably, when at least one of the following conditions is applicable, it is proposed that the automatic neighbor relation message indicates that the user equipment is located inside the second cell area:

[0045] - the automatic neighbor relation message includes a measurement result related to the second base station;

[0046] - the timing advance of the first base station is lower than a predefined threshold;

[0047] - The location value contained in the automatic neighbor relation message matches the estimated geographical boundaries of the second cell area.

[0048] The first option comprises receiving, at the respective user equipment, a measurement result from a signal transmitted from the second base station and reporting the measurement result with an ANR message from the user equipment. In particular, this is the case when the measurement result is above a certain threshold, such as a predefined suitability level. The measurement may take into account one beam, a group of beams or a plurality of beams received above a certain threshold, i.e. the user equipment may be located in an overlapping area of ​​two beams.

[0049] When the user equipment can receive the signal from the second base station well enough, it is located in the second cell area.

[0050] However, the opposite does not apply, and therefore, in the case where the user equipment does not supply measurement results, an additional option is needed to find out whether the user equipment is located in a cell area.

[0051] Therefore, a second option is that the timing advance (TA) value of the first base station is below a predefined threshold.This timing advance value is particularly relevant when the first base station and the second base station are located close together, in particular when mounted on the same tower.

[0052] To this end, at least optionally, the timing advance value will preferably be part of the automatic neighbor relation message from the user equipment.

[0053] With the timing advance value, a rough estimate of the distance to the first base station is available, which gives a good picture of whether the user equipment is located in the second cell area. Since NR applies the time-frequency grid to all resource allocations for dedicated user equipment, the user equipment needs to know the TA anyway during UL reporting. Therefore, the value can be included in the UL report without burden by some or all user equipment, or is known by the base station when the user equipment attempts to report.

[0054] However, it may be beneficial to provide measurement recommendations by broadcasting, as in particular in a first step reaching all user equipments. This is particularly useful for later discarding user equipments that have sent empty reports with too large a TA and thus reducing the number of user equipments to be considered in further steps to a smaller number.

[0055] It is proposed with a third option to provide a location value for the automatic neighbor relation message. This may be a geographical coordinate pair in terms of longitude / latitude, either as an absolute value or as a difference from a reference point in order to save bits. In addition, a geographic code (such as a spatial quadruple code), in particular a geographic code with adjustable resolution, can be used to provide a representation of the location value. Such a location value can then be matched within the geographic boundaries of the cell area. Typically, these geographic boundaries are defined by a vector of the center location longitude / latitude and a radius. Preferably, a tolerance value is added to the radius to cover good signaling conditions.

[0056] Thereby, an accurate calculation for answering the question whether the user equipment is located inside the second cell area can be reliably given, but it requires that the ANR message from the user equipment is enhanced by the value vector.

[0057] With regard to the relationship of the different options, it is provided in a further advantageous embodiment that, in case the automatic neighbor relation message does not comprise a measurement result of the second base station, said automatic neighbor relation message comprises only a location indication.

[0058] This embodiment preferably saves information and processing effort, because redundant information in the ANR message is avoided. If the measurement is received, the first base station knows that the user equipment is in the second cell area. Therefore, the first base station will not even look at the location indication (or timing advance value) for assessing whether the user equipment is in the second cell area.

[0059] Hence, this redundant information can be omitted and thus effort at the user equipment site is saved.

[0060] According to another preferred embodiment, the following steps are further proposed:

[0061] - analyzing whether the plurality of automatic neighbor relation messages include information related to the second base station,

[0062] - instructing the second base station to modify beamforming taking into account the position indications of the plurality of automatic neighbor relation messages.

[0063] With this embodiment, it is proposed not only to evaluate the current status of the cell area coverage through the second base station, but also to take measures in case the coverage does not conform to the spatial distribution of user equipment, especially those user equipment operating stationarily, such as certain types of IoT devices, such as metering equipment, house automation and security equipment, etc.

[0064] As part of this embodiment, it is therefore proposed that the first base station additionally analyzes a plurality of automatic neighbor relation messages acknowledged by the method step of receiving at least one automatic neighbor relation message.

[0065] As part of this, it is checked whether the ANR message includes information related to the second base station.

[0066] Such information related to the second base station specifically includes one of the following groups:

[0067] - a cell identifier of the second base station,

[0068] - a beam identifier associated with the second base station,

[0069] - a power measurement of the signal received from the second base station,

[0070] - Information related to the identity for which the instruction is measured.

[0071] Therefore, the information provided in the ANR message specifically covers the cell identifier of the second base station or one of the group of beam identifiers of the second base station. It is thus clear to the first base station that the user equipment is able to decode signals from at least one beam of the second base station. Therefore, the user equipment is located inside the second cell area.

[0072] The same finding applies to the case where a power measurement of the signal received from the base station is submitted together with the ANR message. This is the most preferred case, as this is where the ANR message is designed for. When the measurement is successful, and accordingly the signal is strong enough, then the user equipment is operating in the second cell area.

[0073] Finally, consider the information related to the identity for which the measurement is instructed. This involves a dedicated measurement instruction for the user equipment. Such a dedicated measurement instruction may involve measuring a certain value in a certain cell. When the certain value of the corresponding second base station is available, this indicates that the user equipment is located in the second cell area.

[0074] When it turns out that a large number of user equipments are located in the second cell area according to their locations, but cannot adequately measure the signals from the base station, the first base station can take measures to improve the situation.

[0075] Therefore, it sends instructions to the second base station for modifying the beamforming.Such instructions specifically take into account the position indication received in the ANR message and thus encourage the second base station to modify the beamforming to cover more user equipments.

[0076] Preferably, the user equipment indicates, for example in an ANR message or in particular during registration, through its capability information, whether they are interested (or allowed to obtain high throughput) in operating with the second base station for obtaining high throughput. If this is not the case, the user equipment, and accordingly its position, can be ignored for correcting the beamforming of the second base station. In particular, NSSAI, i.e., slice selection assistance information provided by the user equipment during initial registration, i.e., each user equipment provides the S-NSSAI (Single Network Slice Selection Assistance Information) of the HPLMN during registration, including QoS information (reference clause TS23.501 5.7): subscribed session-AMBR, default 5QI and default ARP. The 5QI includes an indication of the type of requested service that the user equipment may want to receive, and therefore it can also check whether the subscription complies with the requested service, and therefore if the service request is served by the second high throughput base station, check whether the user equipment will be a suitable candidate.

[0077] With the change of network optimization goals for NR deployments, especially NR deployments in FR2, it is no longer intended to achieve continuous coverage - as this is not possible, but to optimize and focus the beams of the user equipment that should be served in FR2 in such a way that the largest possible group of all user equipment present in the second cell can be served by the second base station, i.e. not to maximize the area but to maximize the number of served user equipment.

[0078] Preferably, the instructions for such measurements are implemented by dedicated instructions. It is proposed that the step of sending a message to at least one user equipment is implemented by means of at least one of broadcast or multicast signaling, the method further comprising the step of implementing a second step of signaling to said at least one user equipment in dedicated type signaling, said second step being further considered for a further automatic neighbor relation evaluation.

[0079] This embodiment means that for the first request of the ANR message, no dedicated signaling is used. All user equipments in the cell area are therefore instructed to send the first ANR message using a common broadcast, respectively multicast (for a group) instruction.

[0080] This broadcast method is not useful when several user equipments are found not to be located in the second cell area. It is therefore proposed that after a first evaluation on the first base station side, further instructions to the remaining user equipments are carried out in a dedicated type of signalling.

[0081] Such dedicated type of signaling is perceptible in particular during an open connection or via a dedicated downlink channel. This means that the user equipment can receive the second request via RRC signaling immediately after reporting the first measurement request. Or unless the preparation is completed, the user equipment remains connected and is then instructed accordingly. Such waiting time can be overcome by applying C-DRX, but it should not be a problem for high-end user equipment anyway. In a less preferred way, such user equipment can also be released to idle and paged after a certain time to get instructions.

[0082] Preferably, the step of sending a message to at least one user equipment by means of broadcast or multicast is carried out taking into account the fraction of user equipment that is within the reachable range of the second base station and within the reachable range of the first base station compared to all user equipment that is within the reachable range of the first base station and can communicate with the second base station.

[0083] This embodiment is directed to the question of when to switch back to broadcast / multicast instructions after implementing the first step of the method of the present invention. Obviously, after the first and / or second base station is installed or activated, the first step is implemented with broadcast instructions. However, especially in the scenario of modifiable beamforming of the mobile user equipment and the second base station, it is disadvantageous to never return to this method.

[0084] For example, when several users with user equipment are active in a certain area (eg, a restaurant terrace), then the beamforming of the second base station is preferably modified to match the terrace.

[0085] When the weather changes, most people will go inside the restaurant, find some cover, or leave the place altogether. Then it does not make sense to focus the beamforming on the terrace, and it does not make sense to request ANR measurements from the same group of user devices, even though they may have left the cell area of ​​the corresponding second base station while still staying in the first cell area around the first base station.

[0086] Therefore, it is proposed that the first base station evaluates received ANR messages, in particular those messages in response to dedicated signalling.

[0087] A simple method is to apply a time trigger, i.e. after a predetermined time of, for example, 1 hour, a broadcast / multicast message is sent to all user equipments residing on the first base station. In addition, when the topology changes, for example, a new base station of the first or second base station type near the first base station can be used as a trigger for the broadcast / multicast instruction signaling.

[0088] In a more detailed approach, it is proposed to consider the fraction of user equipment in the reachable range of the second base station compared to the user equipment located in the first cell area that can communicate with the second base station. Thus, the fraction represents the share of those in the reachable range of the second base station over those located in the first cell area and reachable by the second base station.

[0089] The latter condition relates to the fact that user equipment that is only capable of operating with 4G base stations may not be counted in the score.

[0090] If the user equipment is able to communicate with the second base station, the first base station knows the connected core elements, in particular the MME and the corresponding AMF.

[0091] Therefore, it is advantageous to define a certain threshold of this score for starting broadcasting again to reset the whole situation.

[0092] The score threshold may be fixed by setting a certain percentage (eg, less than 50%).

[0093] Preferably, the threshold is adaptive, because, depending on the need for reaction, the percentage reduction within the last period of time (e.g. 10 minutes or 1 hour) is taken into account to identify a drop as in the terrace example above. This adaptive threshold is advantageous because it automatically adapts to the current situation. Even when the restaurant terrace is full of people, the beam of the second base station may not reach a good share of the user equipment due to the uniform distribution over a fairly large area. Therefore, here in the case of a fixed threshold, a fairly low score can permanently restart the broadcast, although no improvement may be achieved, for example by correcting the beam.

[0094] Therefore, it is preferred to also note the drop in scores from lower overall levels.

[0095] According to a second aspect of the present invention, a base station operating with a cellular network is provided, which covers a first cell area and is connectively coupled to a second base station supporting beamforming and covering a second cell area, wherein a plurality of user equipments are located in the first cell area, the base station being configured to:

[0096] - sending a message representing an instruction to perform at least one automatic neighbor relation measurement to at least one user equipment among a plurality of user equipments located in the first cell area,

[0097] - receiving at least one automatic neighbor relation message from said at least one user equipment,

[0098] - in case the automatic neighbor relation message indicates that the user equipment is located outside a second cell area, omitting the at least one user equipment from further consideration for a further automatic neighbor relation evaluation.

[0099] The base station of this aspect of the present invention relates to the first base station of the first aspect of the present invention.

[0100] It is equipped with transmitting and receiving circuits, and at least one antenna. It further comprises processing circuits for controlling the transmitting and receiving circuits. Preferably, it further comprises volatile and permanent memories for storing at least operating software and configuration data.

[0101] The base station is further equipped with a communication circuit for communicating with a core network component (such as an MME or an AMF) of the cellular network to which it belongs. The communication circuit is particularly set up by wire.

[0102] The base station is configured to support the LTE (4G) technology standard for non-standalone operation, or New Radio (NR, 5G) or higher technology standards.

[0103] The base station further has, directly or indirectly, a communication circuit for communicating with a second base station.

[0104] Preferably, the second base station is installed at the same site, in particular at the same tower.It is further foreseen that the first and second base stations share hardware components, such as antennas, processing circuits and / or memories, for performing their tasks.

[0105] The first base station is configured to send an instruction to the second base station.

[0106] The second base station is additionally configured to perform beamforming, ie it is able to operate in a higher frequency region than the first base station and thus perform communication tasks with a higher throughput than the first base station.

[0107] Through transmit and receive circuits and antennas, the first base station is configured to serve a plurality of user equipments that can support the same technical standard as the first base station.

[0108] The second aspect of the present invention shares the advantages of the first aspect of the present invention.

[0109] As shown, the present invention advantageously solves the depicted problem and provides a solution that copes with the new scenarios of coverage-oriented and throughput-oriented base stations in 5G and beyond in an advantageous manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0110] The following description and drawings set forth certain illustrative aspects in detail and are indicative of only a few of the various ways in which the principles of the embodiments may be employed. The characteristics and advantages of the present invention will become apparent when reading the following description and drawings of advantageous embodiments given as illustrative and non-limiting examples.

[0111] Figure 1represents a base station of the type to which the present invention is applied as an embodiment of a user equipment in a cell area in combination with a second base station and a first base station;

[0112] Figure 2 represents a base station in the second exemplary embodiment;

[0113] Figure 3 A sequence diagram showing an exemplary embodiment of the method of the present invention for a base station is shown.

[0114] Figure 1 A first base station 2 of the type to which the present invention as an embodiment applies is schematically shown. The first base station 2 is communicatively coupled to a second base station 3. Both are part of a cellular network 1 comprising a plurality of base stations of the first 2 and second 3 types.

[0115] The first base station operates in particular in 4G or 5G and higher technical standards. It is a base station for coverage-oriented communications. It covers a first cell area 4. Since it is coverage-oriented, user equipment 7 located in the first cell area 4 can operate with the first base station as long as it has sufficient capacity.

[0116] The situation is different for the second base station 3. The second cell area 5 is the theoretical coverage area of ​​the second base station. In this exemplary case, the first and second base stations are installed on the same tower. Therefore, the first and second cell areas overlap. In this example, the second cell area is completely located in the first cell area.

[0117] As mentioned, the second cell area is the theoretical coverage area for user equipment 7 located in the second cell area. Instead, when the beam 6 is directed to the location where the user equipment 7 is currently located, only those user equipment can be served.

[0118] Therefore, for Figure 1 Different conditions apply to the various user equipment shown in. Under the assumption that all user equipment are capable of operating with both the first and second base stations, user equipment 7.1-7.9 all reside on the first base station.

[0119] When the first base station instructs the user equipment to send an automatic neighbor relation message to the first base station, the following shall apply:

[0120] The user equipments 7.6 and 7.7 do not receive a signal from the second base station. Therefore, they will provide a location indication, for example a geographical location in latitude / longitude, to the ANR message.

[0121] Thereby, the first base station 2 can deduce that they are located outside the second cell area 5 and can therefore be removed from the list of user equipments available for ANR messages with respect to the second base station 3 .

[0122] User equipment 7.5, 7.8 and 7.9 will deliver ANR messages with measurement results and / or additional information about the second base station 3. From this, the first base station 2 can derive that these user equipments are located within the second cell area 5 and that they are within the range of the beam 6 of the second base station 3 and can therefore operate with the second base station. Such operation can be a high data throughput communication session.

[0123] However, user equipments 7.1, 7.2, 7.3 and 7.4 will, like user equipments 7.6 and 7.7, send in their ANR messages an indication of their positions but no measurements due to the fact that they cannot receive signals due to the lack of beamforming covering these user equipment positions.

[0124] However, the first base station will not omit these user equipments as they are located inside the second cell area. A change in beamforming may result in a situation where they can indeed communicate with the second base station 3.

[0125] For subsequent instructions to send ANR messages, the first base station will therefore preferably send instructions in dedicated mode to all shown user equipments except user equipments 7.6 and 7.7.

[0126] Depending on the results of the ANR message received at the first base station 2, it may be preferable to take additional measurements to improve the coverage situation of the second base station 3. The results of such measurements are Figure 2 Shown in.

[0127] Here it is shown that the second base station 3 has modified its beamforming configuration based on the instructions received from the first base station 2. The first base station analyses the location information from the user equipment 7 and figures out that most of the user equipment are not covered by the beam 6.

[0128] Thus, with the correction of the beam, a greater share of the user equipment located in the second cell area is therefore covered. This is possible due to the ANR messages requested from the individual user equipments, which indicate that they are located in the second cell area. Information 7.6 and 7.7 from user equipments outside the second cell area can be omitted, since they will not be able to contribute to a better correction of beam 6. Therefore, it is preferred for both the user equipment involved and the first base station if they are not instructed to send ANR messages about the second base station 3.

[0129] exist Figure 3 In FIG. 1 , an exemplary sequence diagram between the first and second base stations and the selected user equipment 7.2, 7.5 and 7.6 is shown. The user equipment is supplemented with Figure 1 and Figure 2 Those shown in Figure 1beamforming configuration.

[0130] The message flow starts with an instruction message M1 from the first base station 2 to all user equipments residing on the first base station (including those shown in the sequence diagram). The instruction message is in particular sent via broadcast, for example with system information. Multicast to a group of user equipments is also included in this option.

[0131] With the instruction message, the receiving user equipment is instructed to carry out measurements with respect to at least one neighboring base station, in particular one of the second base station type.

[0132] Such measurements are performed by each receiving user equipment with messages M2-M4. The messages as shown are to be understood as attempts to measure signals from the second base station 3. However, if the user equipment 7.2, 7.5, 7.6 is not within the reach of the second base station, the beam of the respective second base station, the messages will not reach the second base station 3.

[0133] After the measurement attempt, the user equipment reports the result of the measurement report to the first base station 2 using Automatic Neighbor Relation (ANR) messages M5, M6, M7.

[0134] The ANR message M5 includes a signal strength value of the user equipment 7.5 located in the direction of one of the beams 6 of the second base station 3. Therefore, it can carry out a measurement and thus indicate a rather high measured signal value to the first base station. This indicates to the first base station that the user equipment 7.5 is operating in the second cell area and even in the beam and should be taken into account for further ANR message transmission.

[0135] The ANR message M6 comprises a position indication from the user equipment 7.2. This position indication is reported as the measurement attempt M3 resulting in no result. Of course, a measured signal value may additionally be reported together with the ANR message M6.

[0136] The ANR message M7 also comprises a location indication from the user equipment 7.6. The situation for the user equipment is similar to that for the user equipment 7.2, since the measurement attempt M4 resulted in no results.

[0137] In step M8, the first base station evaluates the received ANR messages M5, M6, M7. This evaluation step has the main task of clarifying which user equipments 7.2, 7.5, 7.6 are to be considered for further ANR instructions.

[0138] Clearly, user equipment 7.5 is to be retained since it provides a measurement of the signal strength.

[0139] However, for user equipment 7.2 and 7.6 the first base station has to distinguish from the received position indication whether the user equipment is located in the second cell area. This is not the case for user equipment 7.6, which is therefore not considered for further ANR operations.

[0140] The user equipment is located within the second cell area 5, and therefore the first base station continues to consider the user equipment for subsequent ANR operations.

[0141] Therefore, the next ANR request, preferably to be carried out after a certain time, is carried out with an instruction message M9 to the user equipment 7.5. This instruction message is carried out in dedicated signaling, meaning that only the user equipment 7.5 receives the instruction.

[0142] In response, the user equipment 7.5 again performs a measurement attempt (not shown) and reports the result to the first base station. In this case, the user equipment may again measure the signal strength of the second base station and thus provide an ANR message M10 with a value indicating the measured signal strength of the second base station 3.

[0143] Then, an ANR request M11 is sent in dedicated signaling to the user equipment 7.2. The user equipment 7.2 performs another measurement attempt, but still cannot measure the signal from the second base station.

[0144] The ANR request M9, M11 specifically instructs the receiving user equipment to perform specific measurements from a specific base station, in this case from the second base station 3. In case the user equipment 7.2 is in the cell area of ​​another base station of the second base station type it will not report a possible positive measurement result since it was not requested.

[0145] Therefore, in message M12, the user equipment 7.2 indicates that measurements cannot be carried out.

[0146] Optionally, another indication related to the location of the user equipment 7.2 is submitted together with the ANR message M12. However, in case the user equipment 7.2 has left the second cell area 5, it may be omitted from the next ANR message transmission.

[0147] Since this is not the case here, the operation continues, in this case with step M13. In this step, the first base station 2 evaluates the ANR messages received after the last set of ANR requests.

[0148] The result of this evaluation step is an instruction sent with a message M14 to the second base station 3 for modifying the beamforming based on the position information of the user equipment in the second cell area 5 not covered by the beam 6 .

[0149] The second base station 3 therefore carries out a change in beamforming with step M14.

[0150] In the next round of ANR requests, the first base station sends ANR requests to the user equipments 7.2 and 7.5 using messages M15 and M17. Because both are now covered by beams (e.g. Figure 2 ), so both user equipments will successfully perform measurement attempts based on the signals received from the second base station 3.

[0151] The result is thus reported to the first base station 2 using ANR messages M16 and M18.

[0152] Preferably, operation continues with this now fairly optimal beam configuration. However, this situation may change. Either in time or through movement of the user equipment 7.

[0153] Therefore, when further ANR request / message operation finds that the fraction of covered user devices compared to theoretically reachable has dropped significantly, then operation starts again with broadcast ANR request M1.

[0154] In the above detailed description, reference is made to the accompanying drawings, which illustrate by way of illustration specific embodiments in which the present invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the present invention. It is to be understood that the various embodiments of the present invention, although different, are not necessarily mutually exclusive. For example, a specific feature, structure or characteristic described herein in conjunction with an embodiment may be implemented in other embodiments without departing from the scope of the present invention. In addition, it is to be understood that the position or arrangement of individual elements in each disclosed embodiment may be modified without departing from the scope of the present invention. Therefore, the above detailed description is not to be understood in a restrictive sense, and the scope of the present invention is limited only by the appended claims properly interpreted together with the full range of equivalents to which the claims are assigned.

Claims

1. A method for a first base station (2) operating with a cellular network (1), the first base station (2) covering a first cell area (4) and being connectively coupled to a second base station (3) supporting beamforming and covering a second cell area (5), wherein a plurality of user equipments (7) are located in the first cell area (4), The method comprises the following steps: - sending a message representing an instruction to perform at least one automatic neighbor relation measurement to at least one user equipment (7) of a plurality of user equipments (7) located in said first cell area (4), - receiving at least one automatic neighbor relation message from said at least one user equipment (7), - in case the automatic neighbour relation message indicates that the user equipment (7) is located outside the second cell area (5), omitting the user equipment (7) located outside the second cell area (5) from further consideration for further automatic neighbour relation evaluation.

2. The method according to claim 1, Further comprising the step of considering said at least one user equipment (7) in case the automatic neighbor relation message indicates that said user equipment (7) is located inside the second cell area (5).

3. The method according to any one of claims 1 or 2, in, The automatic neighbor relation message indicates that the user equipment (7) is located inside the second cell area (5) if at least one of the following conditions applies: - the automatic neighbor relation message comprises a measurement result related to the second base station (3); - the timing advance of the first base station (2) is below a predefined threshold; - The location value contained in the automatic neighbor relation message matches the estimated geographical boundaries of the second cell area (5).

4. The method according to any one of claims 1 or 2, in, In the case where the automatic neighbor relation message does not include the measurement result of the second base station (3), the automatic neighbor relation message only includes the location indication.

5. The method according to any one of claims 1 or 2, Further comprising the steps of: - analyzing whether the plurality of automatic neighbor relation messages include information related to the second base station (3), - instructing the second base station (3) to modify the beamforming taking into account the position indications of the plurality of automatic neighbor relation messages.

6. The method according to claim 5, The information related to the second base station (3) is at least one of the following groups: - a cell identifier of the second base station (3), - a beam identifier associated with the second base station (3), - a power measurement of the signal received from the second base station (3), - Information related to the identity for which the measurement was ordered.

7. The method according to any one of claims 1 or 2, wherein the step of sending a message to at least one user equipment (7) is performed by means of at least one of broadcast or multicast signaling, The method further comprises the step of carrying out the second step of signalling to the at least one user equipment (7) in dedicated type signalling, the second step being further considered for a further automatic neighbour relation evaluation.

8. The method according to any one of claims 1 or 2, The step of sending a message to at least one user equipment (7) by means of broadcast or multicast is carried out taking into account the share of user equipment (7) that is within the reachable range of the second base station (3) and within the reachable range of the first base station (2) compared to all user equipment (7) that is within the reachable range of the first base station (2) and can communicate with the second base station (3).

9. A base station operating with a cellular network (1), the base station being a first base station (2), the first base station (2) covering a first cell area (4) and being connectively coupled to a second base station (3) supporting beamforming and covering a second cell area (5), wherein a plurality of user equipments (7) are located in the first cell area (4), The base station includes a transmitting circuit and a receiving circuit, and is configured to: - using a transmitting circuit to send a message representing an instruction to perform at least one automatic neighbor relation measurement to at least one user equipment (7) of the plurality of user equipments (7) located in the first cell area (4), - receiving at least one automatic neighbor relation message from said at least one user equipment (7) using a receiving circuit, - in case the automatic neighbour relation message indicates that the user equipment (7) is located outside the second cell area (5), omitting the user equipment (7) located outside the second cell area (5) from further consideration for further automatic neighbour relation evaluation.

10. The base station according to claim 9, Wherein the automatic neighbor relation message indicates that the user equipment (7) is located inside the second cell area (5) when at least one of the following conditions applies: - the automatic neighbor relation message includes the measurement result of the second base station (3); - the timing advance of the first base station (2) is below a predefined threshold; - The location value contained in the automatic neighbor relation message matches the estimated geographical boundaries of the second cell area (5).

11. The base station according to any one of claims 9 or 10, It is further configured as: - analyzing whether the plurality of automatic neighbor relation messages include information related to the second base station (3), - instructing the second base station (3) to modify the beamforming taking into account the position indications of the plurality of automatic neighbor relation messages.

12. The base station according to claim 11, The information related to the second base station (3) is at least one of the following groups: - a cell identifier of the second base station (3), - a beam identifier associated with the second base station (3), - a power measurement of the signal received from the second base station (3), - Information related to the identity for which the measurement was ordered.

13. The base station according to any one of claims 9 or 10, The invention is configured to carry out the sending of messages to at least one user equipment (7) by means of at least one of broadcast or multicast signalling, and to carry out a second step of signalling to the at least one user equipment (7) in dedicated type signalling, the second step being further considered for a further automatic neighbour relation evaluation.

14. The base station according to any one of claims 9 or 10, It is further configured to implement the sending of a message to at least one user equipment (7) by means of broadcast or multicast, taking into account the share of user equipment (7) that is within the reachable range of the second base station (3) and within the reachable range of the first base station (2) compared to all user equipment (7) that is within the reachable range of the first base station (2) and can communicate with the second base station (3).

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