WO2023277744A1

WO2023277744A1 - Channel modelling

Info

Publication number: WO2023277744A1
Application number: PCT/SE2021/050656
Authority: WO
Inventors: Niklas JALDÉN; Magnus Thurfjell; Henrik Asplund
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2021-06-30
Filing date: 2021-06-30
Publication date: 2023-01-05

Abstract

Disclosed is a method (500) performed by a network node (110), the method (500) comprises transmitting (510), by an advanced antenna system, (200) of the network node (110), training sequences using a predetermined configuration (413) and receiving (520), from a first wireless device (120), a channel information report (410) indicative of a preferred configuration (415) of a plurality of different predetermined configurations (413). Further to this, the method (500) comprises determining (530) a channel model (425) associated with the first wireless device (120) by mapping (535) the received preferred configuration (415) to one or more historic reference signal reports (420), estimating (540), based on the determined channel model (425), an interference level between the first wireless device (120) and one or more additional wireless devices (120), and updating (550) a configuration of the network node (110) for subsequent transmissions to the first wireless device (120) based on the estimated interference level.

Description

CHANNEL MODELLING

TECHNICAL FIELD

The present invention relates to interference estimation in a wireless communications network and more precisely to interference estimation using improved channel modelling.

BACKGROUND Modern and future cellular system are becoming more and more advanced in order to improve throughput, coverage, capacity etc. Several techniques are available to improve cellular systems and one such technique is the use of advanced antenna systems, AAS. Generally, AAS offers improved coverage and capacity by providing features such as diversity, multiplexing and beamforming. The improvements with regards to e.g. throughput, coverage and/or capacity are dependent on how well the AAS is adapted to the spatial nature of a channel used for signaling. The level of adaptation of the AAS to the channel will determine the ability of the AAS to direct energy at the target (or source), and how well it avoids emitting energy that interfere with other users. One specific capacity boosting feature in a cellular system is the use of spatial multiplexing and joint transmission to multiple users at the same time. This is known as multi-user multiple inputs multiple outputs, MU-MIMO. MU-MIMO utilizes the diversity, multiplexing and beamforming features of the AAS. In order to do this reliably, MU-MIMO depends on accurate channel estimates or channel state information.

Generally, in MU-MIMO systems, channel state information is obtained by utilization of standardized codebooks. These codebooks specify a configuration of the AAS that is utilized by a base station when communicating with a single wireless device. However, as there are a limited number of entries in these codebooks, the granularity is coarse and albeit the entries of the codebook are orthogonal, due the complexity of the channel, there are situations where, due to e.g. poor channels, signals are not orthogonal at the wireless devices. SUMMARY

It is in view of the above considerations and others that the various embodiments of this disclosure have been made. The present disclosure therefor recognizes the fact that there is a need for improvement of the existing art described above.

An object of the present disclosure is to provide a new type of channel estimation which is improved over prior art and which eliminates or at least mitigates the drawbacks discussed above. More specifically, an object of the invention is to provide a channel estimation that is sufficiently accurate to estimate interference at a receiving wireless device. These objects are achieved by the technique set forth in the appended independent claims with preferred embodiments defined in the dependent claims related thereto.

In a first aspect, a method performed by a network node is presented. The method 500 comprises transmitting, by an advanced antenna system, AAS, of the network node, training sequences using a predetermined configuration. The method further comprises receiving, from a first wireless device, a channel information report indicative of a preferred configuration of a plurality of different predetermined configurations and determining a channel model associated with the first wireless device by mapping the received preferred configuration to one or more historic reference signal reports. Further to this, the method comprises estimating, based on the determined channel model, an interference level between the first wireless device and one or more additional wireless devices, and updating a configuration of the network node for subsequent transmissions to the first wireless device based on the estimated interference level.

In one embodiment, the method further comprises, for each of said one or more additional wireless devices, receiving a channel information report indicative of a preferred configuration of said plurality of different predetermined configurations; determining a channel model associated with the additional wireless device by mapping the preferred configuration received from the additional wireless device to one or more of the historic reference signal reports. Wherein the estimated interference level is further based on the channel model associated with the additional wireless device. This is beneficial as two accurate channel models are available and it is possible to accurately estimate an interference level at the first wireless device caused by a transmission to the additional wireless device - or vice versa.

In one embodiment, the method further comprises transmitting data to the first wireless device and transmitting data to at least one of said one or more additional wireless devices utilizing the updated configuration of the network node. This is beneficial as the detailed interference estimation on which the updated configuration is based reduces the risk of unwanted interference with increased throughput and reduced latency as a result.

In one embodiment of the method, the estimating of an interference level further comprises determining a first interference level indicative of an interference from a transmission by the network node to the first wireless device, to said at least one of said one or more additional wireless devices, and determining a second interference level indicative of an interference level from a transmission by the network node to said at least one of said one or more additional wireless devices, to the first wireless device. The accurately estimated interference levels may be used to decide whether or not to schedule e.g. MU-MIMO transmission to the wireless devices.

In one embodiment of the method, responsive to the estimated interference level being at or below an interference threshold, the updated configuration is such that the transmitting of data to the first wireless device and the transmitting of data to said at least one of said one or more additional wireless devices are performed simultaneously, or substantially simultaneously at a substantially same frequency. This is beneficial since it has been determined that the likelihood for interference is low, there is a high chance that the simultaneous transmission will result in an increased throughput and reduced latency for the wireless devices.

In one embodiment of the method, responsive to the determined interference level being above an interference threshold, the updated configuration is such that the transmitting of data to the first wireless device and the transmitting of data to said at least one of said one or more additional wireless devices are performed at different points in time and/or at different frequencies. This is beneficial as the transmissions, if done simultaneously, are likely to interfere at the receiving wireless devices causing missed or corrupted data packets increasing latency and decreasing throughput due to e.g. retransmissions and signaling overhead.

In one embodiment of the method, it further comprises receiving reference signal reports from one or more wireless devices connected to the network node, and for each of the received reference signal reports the method comprises determining an expected preferred configuration of said plurality of different predetermined configurations based on the received reference signal report, and storing at least a part of and/or a summary of the reference signal report and its associated expected preferred configuration as a historic reference signal report. This is beneficial as it enables the storage of reference signal reports with expected preferred configurations for future reference.

In one embodiment of the method, the determining of the expected preferred configuration comprises determining a direction of arrival of the reference signal report and mapping the determined direction of arrival to a direction of arrival of one of said plurality of different predetermined configurations. This is beneficial as there is a high likelihood that the direction of arrival of the reference signal report will be the same as a direction of arrival of a preferred configuration reported from the same wireless device as reported the reference signal report.

In one embodiment of the method, the received reference signal report is associated with an expected preferred configuration of said plurality of different predetermined configurations having substantially the same direction of arrival as the reference signal report. Further to this, the storing comprises grouping of the reference signal report and its associated expected preferred configuration based on their direction of arrival. This is beneficial as there is a high likelihood that the direction of arrival of the reference signal report will be the same as a direction of arrival of a preferred configuration reported from the same wireless device as reported the reference signal report. In addition to this, the grouping by direction of arrival makes it faster and more efficient to locate a historic reference signal report based on a received channel information report. In one embodiment of the method, the determining of an expected preferred configuration comprises calculation of a Precoding Matrix index, PMI, a Rank Indicator, RI, and/or a Channel Quality Indicator, CQI.

In one embodiment of the method, the reference signal reports are stored in the form of long term channel covariance data. This is beneficial as it reduces a size of the stored data.

In one embodiment of the method, it further comprises requesting a reference signal report from one or more wireless devices located at a direction from the network node from which a preferred configuration has been reported, but an associated reference signal report is missing or is obsolete. This is beneficial as it helps ensure that historic reference signal reports are up to date and available for substantially all channel information reports.

In one embodiment of the method, it further comprises updating the interference threshold based on positive and/or negative acknowledgements, ACK/NACK, received from the first wireless device and said one or more additional wireless devices in response to the data transmitted to the respective wireless device. This is beneficial as ACK/NACK data provides an indication of how much interference transmission cause and an adaptive threshold ensures an efficient method.

In one embodiment of the method, said plurality of different predetermined configurations are beamforming parameters for codebook-based beamforming.

In one embodiment of the method, the channel information report is a Channel State Information, CSI, report.

In one embodiment of the method, the network node is configured to operate in Time Division Duplex, TDD. This is beneficial as the reciprocity of the radio channel makes a signal reference report from a wireless device, i.e. an uplink channel estimate, accurate also for a downlink channel estimate.

In one embodiment of the method, the transmitting of data to the first wireless device is performed using one of said plurality of different predetermined configurations applied to the AAS, and transmitting of data to said one or more additional wireless devices is performed using another one of said plurality of different predetermined configurations applied to the AAS. This is beneficial as the configurations generally are orthogonal ensuring that a risk of interference is minimized.

In one embodiment of the method, it further comprises updating one or more of said plurality of different predetermined configurations based on the estimated interference level. This is beneficial as it makes it possible to actually update e.g. a GoB based on acquired information.

In one embodiment of the method, the channel models are reference signal reports relating to at least one of a Demodulation Reference Signal, DMRS, Phase Tracking Reference Signal, PTRS, Sounding Reference Signal, SRS and/or a Channel State Information Reference Signal, CSI-RS.

In a second aspect, a network node comprising an advanced antenna system, AAS, a controller and one or more memories is presented. The controller is operatively connected to the AAS and said one or more memories. The controller is configured to cause the AAS to transmit a training sequence using a plurality of different predetermined configurations and, receive, from a first wireless device, a channel information report indicative of a preferred configuration of said plurality of different predetermined configurations. Further to this the controller is configured to compare the received preferred configuration to a plurality of historic reference signal reports to determine a channel model associated with the first wireless device and to estimate, based on the determined channel model, an interference level between the first wireless device (120) and one or more additional wireless devices. Further to this, the controller is configured to update a configuring of the network node based on the estimated interference level.

In one embodiment of the network node, the controller is further configured to perform the method of any of the first aspect.

In a third aspect, a wireless network comprising at least one network node, a first wireless device and at least one additional wireless device. The network node is the network node according to the second aspect.

In a fourth aspect, a computer program is presented. The computer program comprises instructions which, when executed on at least one controller of network node, cause the at least one controller to carry out the method according to the first aspect. In a fifth aspect, a carrier comprising the computer program of the fourth aspect is presented. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects, features and advantages will be apparent and elucidated from the following description of various embodiments; references being made to the appended diagrammatical drawings which illustrate non-limiting examples of how the concept can be reduced into practice.

Fig. l is a schematic view of a wireless network according to some embodiments;

Fig. 2 is a schematic perspective view of an advanced antenna system according to some embodiments;

Fig. 3 is a schematic view of signal propagation according to some embodiments;

Figs. 4a-c are schematic illustrations of information flow according to some embodiments;

Fig. 5 is a schematic view of a method according to some embodiments;

Fig. 6 is a schematic view of a network node according to some embodiments;

Fig. 7 is a schematic view of a computer program product according to some embodiments;

Fig. 8 is a carrier for a computer program product according to some embodiments;

Fig. 9 schematically illustrates a telecommunication network connected via an intermediate network to a host computer;

Fig. 10 is a generalized block diagram of a host computer communicating via a base station with a user equipment over a partially wireless connection; and

Figs. 11 to 12 are flowcharts illustrating methods implemented in a communication system including a host computer, a base station and a user equipment. DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, certain embodiments will be described more fully with reference to the accompanying drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the invention, such as it is defined in the appended claims, to those skilled in the art.

The term "coupled" is defined as connected, although not necessarily directly, and not necessarily mechanically. Two or more items that are "coupled" may be integral with each other. The terms "a" and "an" are defined as one or more unless this disclosure explicitly requires otherwise. The terms "substantially," "approximately," and "about" are defined as largely, but not necessarily wholly what is specified, as understood by a person of ordinary skill in the art. The terms "comprise" (and any form of comprise, such as "comprises" and "comprising"), "have" (and any form of have, such as "has" and "having"), "include" (and any form of include, such as "includes" and "including") and "contain" (and any form of contain, such as "contains" and "containing") are open-ended linking verbs. As a result, a method that "comprises," "has," "includes" or "contains" one or more steps possesses those one or more steps, but is not limited to possessing only those one or more steps.

The inventors behind this disclosure have realized that, as codebook based feedback is provided to a network node by a wireless device; the network node will have no accurate information relating to how transmissions generated by the network node interfere at wireless devices. This will be further explained in the coming sections.

In Fig. 1, a wireless network 10 is schematically illustrated. The wireless network 10 comprises at least one network node 110 and a number of wireless devices 120. The network node 110 transmits information to the wireless devices in beams 130. Each beam 130 may comprise information, signals or transmissions for more than one wireless device 120, as is known from systems utilizing e.g. MU-MIMO. That is to say, the beam 130 may comprise a plurality of signals, each intended for different recipients, which may result in the plurality of signals interfering at the end of the recipient. Generally, the different signals are coded using orthogonal codes, and transmitted in a spatially orthogonal manner.

The forming of a beam 130, i.e. beamforming, may be provided by an advanced antenna system, AAS, 200 as illustrated in Fig. 2. The AAS 200 comprises a plurality of antenna segments 210 generally arranged in a matrix structure. Each antenna segment 210, when activated, forms a beam portion 135, and these beam portions combine into the beam 130. By providing, or receiving for that matter, signals to the antenna segments 210 at different phases, a direction of a beam portion 135 may be controlled. Consequently, the AAS 200 may be configured to simultaneously transmit multiple transmission at different direction in one beam 130. The network node 110 learns of a preferred configuration 415 (presented in Fig. 4) associated with a wireless device 120 for the AAS 200 by transmitting training sequences using predetermined configurations 413 (presented in Fig. 4) to the wireless device 120. That is to say, the network node 110 transmits a training sequence that the wireless devices 120 listen to in order to derive a good option for a downlink, DL, precoder, i.e. how to combine the antennas of the network node 110 when transmitting. Based on the training sequence, the wireless device 120 determines the preferred configuration 415, i.e. precoding, and signals this back to the network node 110. In order to keep the signaling overhead low, the codebooks contain a limited set of combinations of DL precoding options. The standardized codebooks typically provide a good balance of uplink, UL, signaling overhead versus DL single user beamforming gain, and thereby beamforming throughput gain. However, the codebook report sent from the wireless device 120 to the network node 110 or base station 110, provide little information of the real channel conditions other than the main direction of arrival/departure. Due to this, codebook- based beamforming, e.g. Type-I Grid of Beams, GoB, is not well suited for MU-MTMO transmissions. Extensive simulations made by the inventors has shown that there are cases where Type-I GoB based MU-MIMO provides a gain, but at equally many locations the increased interference results in a net loss. The core reason for this is the lack of detailed channel info for inter layer interference suppression.

Another option for obtaining channel information is to let the wireless device 120 send training sequences, e.g. sounding reference signals, SRS, to the network node 110. With this option, the network node 110 may estimate the UL channel and acquire a Channel State Information, CSI. By utilizing that wireless channels are reciprocal, the estimated UL channel may be used for DL precoding. SRS based channel information is typically well suited for time division duplexing, TDD, systems where the UL and DL occupy the same frequency bands, but are usable, albeit less accurate, also in frequency division duplexing FDD. An SRS based channel state information method typically provides richer information of the actual channel condition compared to the codebook based approach. Consequently, the SRS based approach is better suited for higher order MIMO transmissions and MU-MIMO. However, as the CSI acquisition, is based on uplink sounding, it is dependent on the uplink power and may therefore not be optimal in poor coverage situations. Further to this, the network resources, SRS resources, needed for a wireless device 120 to provide channel state information are limited, the SRS utilize the same frequency spectrum as the main data communication. In other words, increasing SRS resources will reduce other signaling resources used for e.g. control and data communication. Consequently, all wireless devices 120 may not be able to utilize the SRS based method.

Turning not to Fig. 3, a purely fictive example of how interference may occur in a MU-MIMO wireless system 10. In Fig. 3, a network node 110 transmits a beam 130 using a first configuration 137a and a second configuration 137b corresponding to predetermined configurations of a codebook, e.g. different precoders, GoB, in Type-I codebook based beamforming. The beam 130 is transmitted to a first wireless device 120a and a second wireless device 120b and result in different signal paths depending on the configuration 137a, 137b. The signal path of each configuration 137a, 137b is affected by objects 20, e.g. buildings, cars etc., causing reflections before the beams 130 arrive at the wireless devices 120a, 120b. The first wireless device 120a finds the first configuration 137a to be the most promising and informs the network node 110 of this by transmitting a channel information report 410 (see Fig. 4) indicating that the first configuration 137a is the preferred configuration 415. The second wireless device 120b finds the second configuration 137b to be the most promising and informs the network node 110 of this by transmitting a channel information report 410 indicating that the second configuration 137b is the preferred configuration 415. From the perspective of the network node 110, the configurations 137a, 137b are spatially orthogonal and seeing as the wireless devices 120a, 120b reported different configurations 137a, 137b as their preferred configuration 415, the network node 110 determines that the same beam 130 may be utilized when transmitting information to both wireless devices 120a, 120b. However, as seen in Fig. 3, the interpolation of the signal path of the second configuration 137b will arrive at the first wireless device 120a and cause interference at the first wireless device 120a. This means that simultaneously transmitting signals to the first and second wireless device 120a, 120b using the first and second configuration 137a, 137b will, at the first wireless device 120a, cause the signal for the second wireless device 120b to interfere with the signal for the first wireless device 120a. In other words, the first configuration 137a and the second configuration 137b are not spatially orthogonal at the first wireless device 120a. It should be mentioned that the example of Fig. 3 is greatly simplified, spatial orthogonality at the receiving wireless device 120 will be affected not only by the transmissions arriving at the same location, but also by e.g. the phase of the signals etc.

From Fig. 3, if the network node 110 had access to an SRS report from the first wireless device 120a, it may be configured to determine that the first configuration 137a and the second configuration 137b not are orthogonal at the first wireless device 120a and abstain from transmitting signal to the first wireless device 120a using the first configuration 137a in the same beam 130 as transmitting signal using the second configuration 137b. This means that in the example of Fig. 3, the network node would consider not to use MU-MIMO when communicating with the first and second wireless devices 120a, 120b.

Figs. 4a-c illustrates a schematic view of information flow for providing more accurate channel estimates. Starting with Fig. 4a, the network node 110 may receive channel information reports 410 and/or reference signal reports 425 from wireless devices 120 in communication with the network node 110. The channel information report 410 may be a report resulting from e.g. the Type-I GoB codebook approach. The channel information report 410 preferably comprise an indicating of a preferred configuration 415 of the wireless device 120 providing the channel information report 410. The preferred configuration 415 is preferably chosen as one configuration of a plurality of predetermined configurations 413. The reference signal report 420 may be sounding reports relating to one or more of e.g. a Demodulation Reference Signal, DMRS, Phase Tracking Reference Signal, PTRS, Sounding Reference Signal, SRS and/or a Channel State Information Reference Signal, CSI-RS.

Turning to Fig. 4b, based on a received reference signal report 425, the network node 110 preferably calculates an expected preferred configuration 417 as one configuration of a plurality of predetermined configurations 413. As an example, the expected preferred configuration 417 may be a precoding matrix indicator, PMI, which may be derived as a direction from which the majority of a received signal power come from. From extensive data mining of network logs, the inventors have realized that the strongest direction of the wide-band average angular direction coincides with the best PMI report form the wireless device 120 in a majority of measured locations. Additionally or alternatively, the expected configuration 417 may comprise calculation of a Rank Indicator, RI, and/or a Channel Quality Indicator, CQI. The expected preferred configuration 417 and its associated received reference signal report 425, or channel model 425, are stored in a storage 115 as a historic reference signal report 420. The storage 115 may be any suitable storage such as e.g. a database, a volatile or non volatile memory, a cloud storage operatively connected to the network node etc. The historic reference signal reports 420 may, in some embodiments, be grouped based on the expected preferred configuration 417, e.g. an expected angle of arrival.

In some embodiments, the determined expected preferred configuration 417 may be replaced with, or extended with, the network node 110 requesting the wireless device transmitting the reference signal report 425 to also transmit a preferred configuration 415. This would mean that both a preferred configuration 415 and a reference signal report 425 are received from the same wireless device 120. This data may be e.g. directly stored in the storage 115, utilized to evaluate an expected preferred configuration 417 associated with the reference signal report 425 and/or utilized to determine a quality of historic reference reports 425 etc.

In some embodiments, grouping of data in the storage 115 may, as previously indicated, be based on information related to a direction of arrival, e.g. an angle, a strongest beam, or similar. This means that reference signal reports 425 that have similar directions of arrival are pooled together. In a variant of this embodiment, also other characteristics of the wireless channel conditions are used, such as received power, timing advance, delay spread, polarization state, etc.

There may be situations wherein historic reference signal reports 420 in the storage 115 are missing or outdated. This could be the case if there have been no SRS transmissions, reference signal report 425, from a particular direction for some time, but wireless devices 120 are present in that direction and are reporting preferred configuration 415. Consequently, in some embodiments, the network node may be configured to schedule SRS resources to complete or fill out e.g. missing, outdated or uncertain information of historic reference signal reports 420 in the storage 115.

It should be mentioned that the received reference signal report 425, when stored as historic reference signal report 420, are not necessarily stored as a full log, but may in some embodiments rather be stored as groups of long term channel covariance information. The grouping may be done over channel characteristics resulting from calculated expected preferred configurations 417 being sufficiently similar. The benefit of such an embodiment is that a required size of the storage 115 is reduced and the storage 115 becomes much more manageable, as the covariance information is much more compact.

Having the database with historic reference signal reports 420 associated with expected preferred configurations 417 may be utilized as illustrated in Fig, 4c. When a wireless device 120 transmits a channel information report 410 indicating a preferred configuration 415 to the network node 110, the network node 110 may be configured to search the storage 115 to find an expected preferred configurations 417 that is similar to the preferred configuration 415 of the received channel information report 410. The expected preferred configurations 417 is, via the historic reference signal report 420, associated with a reference signal report 425, or channel model 425, which may be utilized when transmitting signals to the wireless device 120. The similarity between the preferred configuration 415 and the received channel information report 410 may be determined by comparing e.g. PMI, Rank Indicator, RI, and/or a Channel Quality Indicator, CQI between the two. It has been shown that there is a high probability that SRS reports, i.e. reference signal reports 425, giving rise to the expected preferred configuration 417, well matches spatial characteristics of a channel of a wireless device 120 providing the channel information report 410.

In further embodiments, the network node 110 may receive channel information reports 410 from a plurality of wireless devices 120, and based on these, the network node 110 may be configured to calculate an interference caused to each of the wireless devises 120 when e.g. co-scheduled in a MU-MIMO transmission. For example, the interference caused to a first wireless device 120 when co-scheduled with a second wireless device 120 may be assessed using the intended precoder, the indicated preferred configuration 415 for the second wireless device 120, and a correlation/covariance matrix obtained from the channel model 425 associated with the historic reference signal report 420 determined to be most similar to the channel information report 410 provided by the first wireless device 120. Similarly, the interference to the second wireless device 120 may be assessed based on the indicated preferred configuration 415 of the first wireless device 120 and a correlation/covariance matrix obtained from a channel model 425 associated with the historic reference signal report 420 determined to be most similar to the channel information report 410 provided by the second wireless device 120.

In a further embodiment, a first interference level is determined indicative of an interference from a transmission by the network node 110 to the first wireless device 120, caused to one or more additional wireless devices 120, such as the second wireless device 120. Additionally or alternatively, a second interference level is determined indicative of an interference from a transmission by the network node 110 to the second wireless device 120, caused to the first wireless device and/or one or more additional wireless devices 120. The determined interference(s) may in some embodiments be compared to an interference threshold. Further embodiments may comprise responsive to the determined interference(s) being below the interference threshold, scheduling transmission to the associated wireless devices 120 in the same beam 130.

Consequently, responsive to the determined interference(s) being above the interference threshold, the network node 110 may be configured to not schedule transmissions to the associated wireless devices 120 in the same beam 130. The interference threshold may be determined based on statistics such that, if the determined interference(s) are at or below the threshold, there is a high probability of an increased throughput when scheduling transmissions in the same beam 130 compared to scheduling transmissions in separate beams 130. If the interference is high, there signal quality will be poor causing bit error and retransmissions which will increase signaling overhead and consume signaling resources and thereby decreasing the overall throughput.

The interference threshold may in some embodiments be an adaptive threshold. The interference threshold may be updated based on positive / negative acknowledgements, ACK/NACK received by the network node 110. As an example, if transmissions are scheduled in the same beam 130 and one or both of the receiving wireless devices 120 responds with a NACK, the interference threshold may be increased such that the exemplified transmissions would not be scheduled in the same beam 130. Generally, the network node 110 may be configured to log ACK/NACK received from wireless devices 120 and to update the interference threshold values to tune it to a working level, as well as what wireless device 120 (PMI) pairs that follow the SINR expectations. This information may be attached to e.g. reference signal reports 425 when stored as historic reference signal reports 420 in the storage 115.

Alternatively or additionally, ACK/NACK data may even be used to prune entries from the storage 115 corresponding to pairs of wireless devices 120 or direction pairs that have poor MU-MIMO performance.

In one embodiment, the reference signal report 425 is an SRS report 425 and may be evaluated by comparing SRS channels resulting in the same, or substantially the same, estimated configuration 417. To exemplify, two positions with the same estimated configuration 417, e.g. GoB, may generally have channels equally fit for MU- MIMO transmissions. As a result, large channel differences within SRS reports mapped to the same estimated GoB may be used as an indicator that the threshold settings for MU-MIMO transmissions should be increased and vice versa.

It should be mentioned that the network node 110 may in some embodiments be configured to adapt precoders, i.e. AAS 200 configuration, for wireless devices 120 based on e.g. covariance information for other wireless devices 120. This may be provided by for example zero forcing, ZF, with or without degrees of regularization. An initial precoder may be determined using the indicated preferred configuration 415, e.g. PMI report information, only, or derived from reference signal reports 425 or a combination of both.

Turning now to Fig. 5, a method 500 performed by the network node 110 will be explained. The method 500 performs at least parts of the technical details and embodiments as listed in this disclosure, and it should be emphasized that albeit not all features of this disclosure are mentioned explicitly as part of the method 500, also these features are, as the skilled person will appreciate, to be considered workable and enabled for the method 500. The method 500 is preferably performed by the network node 110 which may be configured to operate in Time Division Duplex, TDD, but it should not be considered as limited to a network node 110 in any specific configuration.

The network node 110 transmits 510, by its AAS 200, training sequences using the previously explained predetermined configuration 413. For instance, in one optional embodiment of the method 500, the predetermined configurations 413 may be beamforming parameters for codebook-based beamforming. As a response to this, the network node 110 receives 520 the channel information report 410 from a first wireless device. In some embodiments of the method 500, the channel information report 410 is a CSI report. As mentioned, the channel information report 410 is indicative of a preferred configuration 415 of a plurality of the different predetermined configurations 413. By mapping 534 the received preferred configuration 415 to one or more of the previously presented historic reference signal reports 420, the network node 110 determines 530 a channel model 417 associated with the first wireless device 120.

Based on the determined channel model 417, the network node 110 estimates 540 an interference level between the first wireless device 120 and one or more additional wireless devices 120 in communication with the network node 110. Based on the estimated interference level, the network node 110 updates 550 a configuration that will be used for subsequent transmissions to the first wireless device 120. This configuration may, as will be clear to the skilled person, be e.g. a configuration to enable or disable MU-MIMO and/or adapting a GoB etc. In one embodiment, the method 500 further comprises the network node 110 transmitting 560 data to the first wireless device 120 and transmitting 560’ data to at least one of said one or more additional wireless devices 120 utilizing the updated configuration of the network node 110.

Optionally, the method 500 may further comprise the reception 520’ of a channel information report 410 from one or more other or additional wireless devices 120 in communication with the network node 110. The channel information report 410 is generally transmitted by the additional wireless devices 120 responsive to the previous detailed transmitting 510 of training sequences by the network node 110. As before, also this channel information report 410 is indicative of a preferred configuration 415 of the plurality of different predetermined configurations 413. Analogously to the process in relation to the first wireless device 120, the network node determines 530’ a channel model 425 associated with the additional wireless device 120 by mapping 535’ the preferred configuration 413 to one or more of the historic reference signal reports 420. This means that the estimated interference level may further be based on the channel model 425 associated with the additional wireless device 120. In one embodiment, the channel models 425 are signal reports 425 relating to at least one of a Demodulation Reference Signal, DMRS, Phase Tracking Reference Signal, PTRS, Sounding Reference Signal, SRS and/or a Channel State Information Reference Signal, CSI-RS.

In one embodiment, the step of estimating 540 an interference level further comprises the network node 110 determining 545 a first interference level indicative of an interference from a transmission by the network node 110 to the first wireless device 120, to said at least one of said one or more additional wireless devices 120. Further to this the method 500 may comprise the network node 110 determining 545’ a second interference level indicative of an interference level from a transmission by the network node 110 to said at least one of said one or more additional wireless devices 120, to the first wireless device 120. In other words, the network node 110 evaluates how transmission from the network node 110 to one wireless device 120 will affect other wireless devices 120 in communication with the network node 110. In a further embodiment of the method 500, if the estimated interference level is at or below the interference threshold, the network node 110 may update 550 the configuration such that the transmitting 560 of data to the first wireless device 120 and the transmitting 560’ of data to said at least one of said one or more additional wireless devices 120 are performed simultaneously, or substantially simultaneously at a substantially same frequency. This may be exemplified that the network node 110 schedules the first wireless device 120 and said one or more additional wireless devices 120 for MU- MIMO. Alternatively or additionally, if the interference level is above the threshold, the updated configuration may be such that the transmitting 560’ of data to the first wireless device 120 and said at least one of said one or more additional wireless devices 120 are performed at different points in time and/or at different frequencies.

In order to create the historic reference signal reports 420, the method 500 may in some embodiments comprise the network node 110 receiving 570 reference signal reports 425, such as SRS reports 425, from one or more wireless devices 120 connected to the network node 110. As previously explained, based on the received reference signal reports 425, an expected preferred configuration 417, of the plurality of different predetermined configurations 413, is determined 580 by the network node. The step of determining 580 may, in some embodiments comprises calculation of a Precoding Matrix index, PMI, a Rank Indicator, RI, and/or a Channel Quality Indicator, CQI. In one further embodiment, the step of determining 580 the expected preferred configuration 417 comprises determining 585 a direction of arrival of the reference signal report 420 and mapping 587 the determined direction of arrival to a direction of arrival of one of said plurality of different predetermined configurations 413. Further to this, the method 500 may comprise associating the received reference signal report 420 with an expected preferred configuration 417, which has substantially the same direction of arrival as the reference signal report 420. In addition to this, or as an option to this, the storing 590 may comprise grouping 595 the reference signal report 420 and its associated expected preferred configuration 417 based on their direction of arrival. In one embodiment, at least a part of the expected preferred configuration 417 is stored 590 together with at least a part of and/or a summary of the reference signal report as a historic reference signal report 420. In a further embodiment, the reference signal reports 425 are stored 590 in the form of long term channel covariance data. As explained before, the method 500 may further comprise the network node 110 requesting 515 a reference signal report 425 from one or more wireless devices 120. This may be the case when wireless devices 120 are located at a direction from the network node 110 from which a preferred configuration 415 has been reported, but an associated reference signal report 420 is missing or is obsolete. As previously mentioned, the network node 110 may further request a wireless device 120 transmitting a reference signal report 425 to also provide a preferred configuration 415.

As explained, the interference threshold may be adaptive or at least adjustable and in one optional embodiment the method 500 further comprises updating 547 the interference threshold based on ACK/NACK received from the wireless devices 120 in response to the data transmitted to the respective wireless device 120.

In one embodiment of the method 500, wherein the transmitting 560 of data to the first wireless device and to said one or more additional wireless devices 120 is performed using different predetermined configurations 413 applied to the AAS 200.

In one embodiment, the method 500 further comprises updating 549 one or more of said plurality of different predetermined configurations 413 based on the estimated interference level. As an example, a particular GoB 413 may be tweaked or reconfigured to decrease the estimated interference level.

Albeit the method 500 is explained as preferably performed by a network node 110, the skilled person will, after digesting the teachings herein, understand that the at least some part of the method 500 may very well be performed by other devices, apparatuses or equipment operatively connected to, or comprised in a wireless network 10. Some tasks of the method 500 may be distributed to e.g. cloud servers or other entities in a communications network.

Turning to Fig. 6, a schematic view of a network node 110 is shown. In this embodiment, the network node 110 comprises an AAS 200, a controller 114 and one or more memories 116. The controller 114 is preferably operatively connected to the AAS 200 and the memories 116. The controller 114 may be configured to cause the AAS 200 to transmit a training sequence using a plurality of different predetermined configurations 413. Further to this, the controlled 114 may be configured to cause the AAS to receive a channel information report 410 from a first wireless device 120, wherein the channel information report 410 is indicative of a preferred configuration 415 the plurality of different predetermined configurations 413. The preferred configuration 415 may be compared to the plurality of historic reference signal reports 420 to determine a channel model 425 associated with the first wireless device 120. Based on the determined channel model 425, the controller 114 may further be configured to estimate an interference level between the first wireless device 120 and one or more additional wireless devices 120. Based on the estimated interference level, the controller 114 may further be configured to update a configuring of the network node 110. The updated configuration is to be used for subsequent transmissions to the first wireless device 110.

It should be mentioned that in further embodiments of the network 110 of Fig. 6, the controller 114 may further be configured to cause the network 110 to perform any of the steps or features mentioned in reference to the method 500 or any other embodiments or examples presented within this disclosure.

The network node 110 of Fig. 6 may, in one embodiment be the network node 110 of Fig. 1, i.e. comprised in a wireless network 10 further comprising a first wireless device 120 and at least one additional wireless device 120.

In Fig. 7, a schematic view of a computer program 650 is shown. The computer program 650 may comprise instructions which, when executed on for instance, at least one controller 114 of the network node 110, cause the controller 114 to carry out the method 500 or any other feature or task as mentioned herein.

Turning to Fig. 8 will reveal a schematic view of a carrier 600 that may comprise the computer program 650 of Fig. 7. Although illustrated as a computer readable storage medium, the carrier 600 may be any one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium.

With reference to Fig. 9, in accordance with an embodiment, a communication system includes a telecommunication network 3210, such as a 3GPP-type cellular network, which comprises an access network 3211, such as a radio access network, and a core network 3214. The access network 3211 comprises a plurality of base stations 3212a, 3212b, 3212c, such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 3213a, 3213b, 3213c. Each base station 3212a, 3212b, 3212c is connectable to the core network 3214 over a wired or wireless connection 3215. A first user equipment (UE) 3291 located in coverage area 3213c is configured to wirelessly connect to, or be paged by, the corresponding base station 3212c. A second UE 3292 in coverage area 3213a is wirelessly connectable to the corresponding base station 3212a. While a plurality of UEs 3291, 3292 are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole UE is in the coverage area or where a sole UE is connecting to the corresponding base station 3212.

The telecommunication network 3210 is itself connected to a host computer 3230, which may be embodied in the hardware and/or software of a standalone server, a cloud-implemented server, a distributed server or as processing resources in a server farm. The host computer 3230 may be under the ownership or control of a service provider, or may be operated by the service provider or on behalf of the service provider. The connections 3221, 3222 between the telecommunication network 3210 and the host computer 3230 may extend directly from the core network 3214 to the host computer 3230 or may go via an optional intermediate network 3220. The intermediate network 3220 may be one of, or a combination of more than one of, a public, private or hosted network; the intermediate network 3220, if any, may be a backbone network or the Internet; in particular, the intermediate network 3220 may comprise two or more sub -networks (not shown).

The communication system of Fig. 9 as a whole enables connectivity between one of the connected UEs 3291, 3292 and the host computer 3230. The connectivity may be described as an over-the-top, OTT, connection 3250. The host computer 3230 and the connected UEs 3291, 3292 are configured to communicate data and/or signaling via the OTT connection 3250, using the access network 3211, the core network 3214, any intermediate network 3220 and possible further infrastructure (not shown) as intermediaries. The OTT connection 3250 may be transparent in the sense that the participating communication devices through which the OTT connection 3250 passes are unaware of routing of uplink and downlink communications. For example, a base station 3212 may not or need not be informed about the past routing of an incoming downlink communication with data originating from a host computer 3230 to be forwarded (e.g., handed over) to a connected UE 3291. Similarly, the base station 3212 need not be aware of the future routing of an outgoing uplink communication originating from the UE 3291 towards the host computer 3230.

Example implementations, in accordance with an embodiment, of the UE, base station and host computer discussed in the preceding paragraphs will now be described with reference to Fig. 10. In a communication system 3300, a host computer 3310 comprises hardware 3315 including a communication interface 3316 configured to set up and maintain a wired or wireless connection with an interface of a different communication device of the communication system 3300. The host computer 3310 further comprises processing circuitry 3318, which may have storage and/or processing capabilities. In particular, the processing circuitry 3318 may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The host computer 3310 further comprises software 3311, which is stored in or accessible by the host computer 3310 and executable by the processing circuitry 3318. The software 3311 includes a host application 3312. The host application 3312 may be operable to provide a service to a remote user, such as a UE 3330 connecting via an OTT connection 3350 terminating at the UE 3330 and the host computer 3310. In providing the service to the remote user, the host application 3312 may provide user data which is transmitted using the OTT connection 3350.

The communication system 3300 further includes a base station 3320 provided in a telecommunication system and comprising hardware 3325 enabling it to communicate with the host computer 3310 and with the UE 3330. The hardware 3325 may include a communication interface 3326 for setting up and maintaining a wired or wireless connection with an interface of a different communication device of the communication system 3300, as well as a radio interface 3327 for setting up and maintaining at least a wireless connection 3370 with a UE 3330 located in a coverage area (not shown in Fig. 10) served by the base station 3320. The communication interface 3326 may be configured to facilitate a connection 3360 to the host computer 3310. The connection 3360 may be direct or it may pass through a core network (not shown in Fig. 10) of the telecommunication system and/or through one or more intermediate networks outside the telecommunication system. In the embodiment shown, the hardware 3325 of the base station 3320 further includes processing circuitry 3328, which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The base station 3320 further has software 3321 stored internally or accessible via an external connection.

The communication system 3300 further includes the UE 3330 already referred to. Its hardware 3335 may include a radio interface 3337 configured to set up and maintain a wireless connection 3370 with a base station serving a coverage area in which the UE 3330 is currently located. The hardware 3335 of the UE 3330 further includes processing circuitry 3338, which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The UE 3330 further comprises software 3331, which is stored in or accessible by the UE 3330 and executable by the processing circuitry 3338. The software 3331 includes a client application 3332. The client application 3332 may be operable to provide a service to a human or non-human user via the UE 3330, with the support of the host computer 3310. In the host computer 3310, an executing host application 3312 may communicate with the executing client application 3332 via the OTT connection 3350 terminating at the UE 3330 and the host computer 3310. In providing the service to the user, the client application 3332 may receive request data from the host application 3312 and provide user data in response to the request data. The OTT connection 3350 may transfer both the request data and the user data. The client application 3332 may interact with the user to generate the user data that it provides.

It is noted that the host computer 3310, base station 3320 and UE 3330 illustrated in Fig. 10 may be identical to the host computer 3230, one of the base stations 3212a, 3212b, 3212c and one of the UEs 3291, 3292 of Fig. 9, respectively.

This is to say, the inner workings of these entities may be as shown in Fig. 10 and independently, the surrounding network topology may be that of Fig. 9.

In Fig. 10, the OTT connection 3350 has been drawn abstractly to illustrate the communication between the host computer 3310 and the use equipment 3330 via the base station 3320, without explicit reference to any intermediary devices and the precise routing of messages via these devices. Network infrastructure may determine the routing, which it may be configured to hide from the UE 3330 or from the service provider operating the host computer 3310, or both. While the OTT connection 3350 is active, the network infrastructure may further take decisions by which it dynamically changes the routing (e.g., on the basis of load balancing consideration or reconfiguration of the network).

The wireless connection 3370 between the UE 3330 and the base station 3320 is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to the UE 3330 using the OTT connection 3350, in which the wireless connection 3370 forms the last segment. More precisely, the teachings of these embodiments may improve the data rate, latency etc. and thereby provide benefits such as e.g. reduced user waiting time, better responsiveness etc.

A measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection 3350 between the host computer 3310 and UE 3330, in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring the OTT connection 3350 may be implemented in the software 3311 of the host computer 3310 or in the software 3331 of the UE 3330, or both. In embodiments, sensors (not shown) may be deployed in or in association with communication devices through which the OTT connection 3350 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which software 3311, 3331 may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 3350 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not affect the base station 3320, and it may be unknown or imperceptible to the base station 3320. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling facilitating the host computer’s 3310 measurements of throughput, propagation times, latency and the like. The measurements may be implemented in that the software 3311, 3331 causes messages to be transmitted, in particular empty or ‘dummy’ messages, using the OTT connection 3350 while it monitors propagation times, errors etc.

Fig. 11 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Figs. 9 and 10. For simplicity of the present disclosure, only drawing references to Fig.

11 will be included in this section. In a first step 3410 of the method, the host computer provides user data. In an optional substep 3411 of the first step 3410, the host computer provides the user data by executing a host application. In a second step 3420, the host computer initiates a transmission carrying the user data to the UE. In an optional third step 3430, the base station transmits to the UE the user data which was carried in the transmission that the host computer initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In an optional fourth step 3440, the UE executes a client application associated with the host application executed by the host computer.

Fig. 12 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Figs. 9 and 10. For simplicity of the present disclosure, only drawing references to Fig.

12 will be included in this section. In a first step 3510 of the method, the host computer provides user data. In an optional substep (not shown) the host computer provides the user data by executing a host application. In a second step 3520, the host computer initiates a transmission carrying the user data to the UE. The transmission may pass via the base station, in accordance with the teachings of the embodiments described throughout this disclosure. In an optional third step 3530, the UE receives the user data carried in the transmission.

Numbered embodiments I . A base station configured to communicate with a user equipment (UE), the base station comprising a radio interface, an advanced antenna system and processing circuitry configured to perform the method (500) as detailed herein.

5. A communication system including a host computer comprising: processing circuitry configured to provide user data; and a communication interface configured to forward the user data to a cellular network for transmission to a user equipment (UE), wherein the cellular network comprises a base station having a radio interface, an advanced antenna system and processing circuitry, the base station’s processing circuitry configured to perform the method (500) as detailed herein.

6. The communication system of embodiment 5, further including the base station.

7. The communication system of embodiment 6, further including the UE, wherein the UE is configured to communicate with the base station.

8. The communication system of embodiment 7, wherein: the processing circuitry of the host computer is configured to execute a host application, thereby providing the user data; and the UE comprises processing circuitry configured to execute a client application associated with the host application.

II. A method implemented in a base station, comprising the steps of transmitting (510), by an advanced antenna system, AAS, (200) of the network node (110), training sequences using a predetermined configuration (413), receiving (520), from a first wireless device (120), a channel information report (410) indicative of a preferred configuration (415) of a plurality of different predetermined configurations (413), determining (530) a channel model (425) associated with the first wireless device (120) by mapping (535) the received preferred configuration (415) to one or more historic reference signal reports (420), estimating (540), based on the determined channel model (425), an interference level between the first wireless device (120) and one or more additional wireless devices (120), and updating (550) a configuration of the network node (110) for subsequent transmissions to the first wireless device (120) based on the estimated interference level.

15. A method implemented in a communication system including a host computer, a base station and a user equipment (UE), the method comprising: at the host computer, providing user data; and at the host computer, initiating a transmission carrying the user data to the UE via a cellular network comprising the base station, wherein the base station: transmits (510), by an advanced antenna system, AAS, (200) of the network node (110), training sequences using a predetermined configuration (413), receives (520), from a first wireless device (120), a channel information report (410) indicative of a preferred configuration (415) of a plurality of different predetermined configurations (413), determines (530) a channel model (425) associated with the first wireless device (120) by mapping (535) the received preferred configuration (415) to one or more historic reference signal reports (420), estimate (540), based on the determined channel model (425), an interference level between the first wireless device (120) and one or more additional wireless devices (120), and update (550) a configuration of the network node (110) for subsequent transmissions to the first wireless device (120) based on the estimated interference level.

16. The method of embodiment 15, further comprising: at the base station, transmitting the user data.

17. The method of embodiment 16, wherein the user data is provided at the host computer by executing a host application, the method further comprising: at the UE, executing a client application associated with the host application. 21. A user equipment (UE) configured to communicate with a base station, the UE comprising a radio interface and processing circuitry configured to, responsive to receiving from an advanced antenna system, AAS, (200) of a network node (110), training sequences using a predetermined configuration (413), transmitting a channel information report (410) indicative of a preferred configuration (415) of a plurality of different predetermined configurations (413). 25. A communication system including a host computer comprising: processing circuitry configured to provide user data; and a communication interface configured to forward user data to a cellular network for transmission to a user equipment (UE), wherein the UE comprises a radio interface and processing circuitry, the UE’s processing circuitry configured to, responsive to receiving, from an advanced antenna system, AAS, (200) of a network node (110), training sequences using a predetermined configuration (413), transmitting a channel information report (410) indicative of a preferred configuration (415) of a plurality of different predetermined configurations (413).

26. The communication system of embodiment 25, further including the UE.

27. The communication system of embodiment 26, wherein the cellular network further includes a base station configured to communicate with the UE.

28. The communication system of embodiment 26 or 27, wherein: the processing circuitry of the host computer is configured to execute a host application, thereby providing the user data; and the UE’s processing circuitry is configured to execute a client application associated with the host application.

31. A method implemented in a user equipment (UE), comprising, responsive to receiving from an advanced antenna system, AAS, (200) of a network node (110), training sequences using a predetermined configuration (413), transmitting a channel information report (410) indicative of a preferred configuration (415) of a plurality of different predetermined configurations (413).

Claims

1. A method (500) performed by a network node (110), the method (500) comprising: transmitting (510), by an advanced antenna system, AAS, (200) of the network node (110), training sequences using a predetermined configuration (413), receiving (520), from a first wireless device (120), a channel information report (410) indicative of a preferred configuration (415) of a plurality of different predetermined configurations (413), determining (530) a channel model (425) associated with the first wireless device (120) by mapping (535) the received preferred configuration (415) to one or more historic reference signal reports (420), estimating (540), based on the determined channel model (425), an interference level between the first wireless device (120) and one or more additional wireless devices (120), and updating (550) a configuration of the network node (110) for subsequent transmissions to the first wireless device (120) based on the estimated interference level.

2. The method (500) of claim 1, further comprising, for each of said one or more additional wireless devices (120): receiving (520’) a channel information report (410) indicative of a preferred configuration (415) of said plurality of different predetermined configurations (413), determining (530’) a channel model (425) associated with the additional wireless device (120) by mapping (535’) the preferred configuration (413) received from the additional wireless device (120) to one or more of the historic reference signal reports (420), and wherein the estimated interference level is further based on the channel model (425) associated with the additional wireless device (120).

3. The method (500) of any of the preceding claims, further comprising: transmitting (560) data to the first wireless device (120) and transmitting (560’) data to at least one of said one or more additional wireless devices (120) utilizing the updated configuration of the network node (110).

4. The method (500) of any of the preceding claims, wherein estimating (540) an interference level further comprises: determining (545) a first interference level indicative of an interference from a transmission by the network node (110) to the first wireless device (120), to said at least one of said one or more additional wireless devices (120), and determining (545’) a second interference level indicative of an interference level from a transmission by the network node (110) to said at least one of said one or more additional wireless devices (120), to the first wireless device (120).

5. The method (500) of claim 3 or 4, wherein, responsive to the estimated interference level being at or below an interference threshold, the updating (550) of the configuration is such that the transmitting (560) of data to the first wireless device (120) and the transmitting (560’) of data to said at least one of said one or more additional wireless devices (120) are performed simultaneously, or substantially simultaneously at a substantially same frequency.

6. The method (500) of any of the claims 3 to 5, wherein, responsive to the determined interference level being above an interference threshold, the updating (550) of the configuration is such that the transmitting (560) of data to the first wireless device (120) and the transmitting (560’) of data to said at least one of said one or more additional wireless devices (120) are performed at different points in time and/or at different frequencies.

7. The method (500) of any of the preceding claims, further comprising: receiving (570) reference signal reports (425) from one or more wireless devices (120) connected to the network node (110), for at least one of the received reference signal reports (425): determining (580) an expected preferred configuration (417) of said plurality of different predetermined configurations (413) based on the received reference signal report (425), and storing (590) at least a part of and/or a summary of the reference signal report (425) and its associated expected preferred configuration (417) as a historic reference signal report (420).

8. The method (500) of claim 7, wherein the determining (580) of the expected preferred configuration (417) comprises determining (585) a direction of arrival of the reference signal report (425) and mapping (587) the determined direction of arrival to a direction of arrival of one of said plurality of different predetermined configurations (413).

9. The method (500) of claim 8, wherein the received reference signal report (425) is associated with an expected preferred configuration (417) of said plurality of different predetermined configurations (413) having substantially the same direction of arrival as the reference signal report (420), and the storing (590) comprises grouping (595) the reference signal report (425) and its associated expected preferred configuration (417) based on their direction of arrival.

10. The method (500) of any of the claims 7 to 9, wherein the determining (580) of an expected preferred configuration (417) comprises calculation of a Precoding Matrix index, PMI, a Rank Indicator, RI, and/or a Channel Quality Indicator, CQI.

11. The method (500) of any on the claims 7 to 10, wherein the reference signal reports (425) are stored (590) in the form of long term channel covariance data.

12. The method (500) of any on the claims 7 to 11, further comprising: requesting (515) a reference signal report (425) from one or more wireless devices (120) located at a direction from the network node (110) from which a preferred configuration (415) has been reported, but an associated reference signal report (425) is missing or is obsolete.

13. The method (500) of any of the claims 5 to 12, further comprising: updating (547) the interference threshold based on positive and/or negative acknowledgements, ACK/NACK, received from the first wireless device (120) and said one or more additional wireless devices (120) in response to the data transmitted to the respective wireless device (120).

14. The method (500) according to any of the preceding claims, wherein said plurality of different predetermined configurations (413) are beamforming parameters for codebook-based beamforming.

15. The method (500) according to any of the preceding claims, wherein the channel information report (410) is a Channel State Information, CSI, report.

16. The method (500) according to any of the preceding claims, wherein the network node (110) is configured to operate in Time Division Duplex, TDD.

17. The method (500) according to any of the claims 5 to 16, wherein the transmitting (560) of data to the first wireless device (120) is performed using one of said plurality of different predetermined configurations (413) applied to the AAS (200), and transmitting (560) of data to said one or more additional wireless devices (120) is performed using another one of said plurality of different predetermined configurations (413) applied to the AAS (200).

18. The method (500) of any of the preceding claims, further comprising updating (549) one or more of said plurality of different predetermined configurations (413) based on the estimated interference level. 19. The method (500) of any of the preceding claims, wherein the channel models (425) are reference signal reports (425) relating to at least one of a Demodulation Reference Signal, DMRS, Phase Tracking Reference Signal, PTRS, Sounding Reference Signal, SRS and/or a Channel State Information Reference Signal, CSI-RS.

20. A network node (110) comprising an advanced antenna system, AAS,

(200), a controller (114) and one or more memories (116), wherein the controller (114) is operatively connected to the AAS (200) and said one or more memories (116), wherein the controller (114) is configured to: cause the AAS (200) to transmit a training sequence using a plurality of different predetermined configurations (413), receive, from a first wireless device (120), a channel information report (410) indicative of a preferred configuration (415) of said plurality of different predetermined configurations (413), compare the received preferred configuration (415) to a plurality of historic reference signal reports (420) to determine a channel model (425) associated with the first wireless device (120), estimate, based on the determined channel model (425), an interference level between the first wireless device (120) and one or more additional wireless devices (120), and update a configuring of the network node (110) for subsequent transmissions to the first wireless device (120) based on the estimated interference level.

21. The network node (110) of claim 20, wherein the controller (114) is further configured to perform the method (500) of any of the claims 2 to 19.

22. A wireless network (10) comprising at least one network node (110), a first wireless device (120) and at least one additional wireless device (120), wherein the network node (110) is the network node (110) according to any of the claims 20 or 21. 23. A computer program (650) comprising instructions which, when executed by at least one controller (114) of network node (110), cause the at least one controller (114) to carry out the method (500) according to any of the claims 1 to 19. 24. A carrier (600) comprising the computer program (650) of claim 23 wherein the carrier (600) is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium.