Beam management procedures for network nodes and terminal devices

Abstract

Mechanisms for performing a beam management procedure are provided. A method is performed by a network node. The method includes obtaining, from a terminal device to which the network node provides network access, configuration information, wherein the configuration information specifies that the terminal device needs to evaluate different polarization states at different time units during a beam management procedure. The method includes performing, with the terminal device, the beam management procedure. The beam management procedure involves the network node transmitting a reference signal per time slot according to a reference signal transmission scheme. The reference signal transmission scheme depends on the obtained configuration information.

Description

TECHNICAL FIELD

[0001] Embodiments presented herein relate to a method, a network node, a terminal device, a computer program, and a computer program product for performing a beam management procedure. BACKGROUND

[0002] In a communication network, there can be challenges to obtain good performance and capacity for a given communication protocol, its parameters, and the physical environment in which the communication network is deployed.

[0003] For example, for future mobile communication networks, there can be a need for bands of many different carrier frequencies. For example, there can be a need for lower frequency bands to enable sufficient network coverage for wireless devices, and higher frequency bands (e.g., in millimeter wavelengths (mmW), i.e., close to and above 30 GHz) to reach a required network capacity. Generally, at high frequencies, the propagation properties of the radio channel are more challenging, and beamforming at both the network node and the wireless device of the network can be needed to reach sufficient link budget.

[0004] At such high frequencies, a narrow-beam transmission and reception scheme can be needed to compensate for the expected high propagation loss. For a given communication link, a respective beam pair link (BPL) can be applied at both the network side (as represented by a network node or its transmission and reception point, TRP) and the terminal (as represented by a terminal device). The BPL (i.e., both the beam used by the network node and the beam used by the terminal device) is expected to be discovered and monitored by the network using measurements on downlink reference signals for beam management, such as channel state information reference signals (CSI-RS) or synchronization signal block (SSB) signals.

[0005] A beam management procedure can be used for the discovery and maintenance of a beam pair link. In some aspects, the beam management procedure is defined in terms of a P-1 sub-procedure, a P-2 sub-procedure, and a P-3 sub-procedure.

[0006] CSI-RS for beam management can be transmitted periodically, semi-persistently or aperiodically (event triggered) and they can be shared between multiple terminal devices or device specific. SSBs are transmitted periodically and shared by all terminal devices. In order for a terminal device to find a suitable network node beam, during the P-1 sub-process, the network node transmits reference signals in different transmit (TX) beams which the terminal device performs measurements on, such as Reference Signal Received Power (RSRP), and reports back N best TX beams (where N can be configured by the network). Furthermore, the transmission of reference signals on a given TX beam can be repeated to allow the terminal device to evaluate a suitable receive (RX) beam. The reference signals shared between all terminal devices served by a TRP can be used to determine a first coarse direction for the terminal device. Such periodic TX beam sweeping at the TRP can be applicable using SSBs as reference signals. One reason for this is that SSBs are anyway transmitted periodically (for initial access / synchronization purposes) and furthermore SSBs are expected to be beamformed at higher frequencies to overcome the above mentioned higher propagation losses.

[0007] Further, a more fine-grained beam sweeping in narrower beams can be performed at the network node during the P-2 sub-process compared to what is used during the P-1 sub-process to determine a more detailed direction for each terminal device. Here, CSI-RS can be used as reference signals. For the P-1 sub-process, the terminal device performs measurements such as Reference Signal Received Power (RSRP) and reports back N best TX beams (where N can be configured by the network).

[0008] Furthermore, the CSI-RS transmission in the transmit beams selected during the P-2 sub-process can be repeated in the P-3 sub-process to allow the terminal device to evaluate a suitable RX beam at the terminal device.

[0009] However, in some aspects, which beam in the respective beam management sub-process that is reported and / or selected by the terminal device as the best beam (e.g. in terms of RSRP) depends to some extent on the antenna architecture at the terminal device. These aspects are not considered during the current beam management procedures.

[0010] Hence, there is still a need for improved beam management procedures. SUMMARY

[0011] It is an object of embodiments herein to provide a beam management procedure taking into account the antenna architecture at the terminal device.

[0012] According to a first aspect, a method for performing a beam management procedure is presented. The method is performed by a network node. The method comprises obtaining, from a terminal device to which the network node provides network access, configuration information, wherein. The configuration information specifies that the terminal device needs to evaluate different polarization states during the beam management procedure with different time units. The method comprises performing, with the terminal device, a beam management procedure. The beam management procedure involves that the network node transmits reference signals per time slot according to a reference signal transmission scheme. The reference signal transmission scheme depends on the obtained configuration information.

[0013] According to a second aspect, a network node for performing a beam management procedure is presented. The network node comprises processing circuitry. The processing circuitry is configured to cause the network node to obtain, from a terminal device to which the network node provides network access, configuration information, wherein. The configuration information specifies that the terminal device needs to evaluate different polarization states during the beam management procedure with different time units. The processing circuitry is configured to cause the network node to perform, with the terminal device, a beam management procedure. The beam management procedure involves that the network node transmits reference signals per time slot according to a reference signal transmission scheme. The reference signal transmission scheme depends on the obtained configuration information.

[0014] According to a third aspect, a network node for performing a beam management procedure is presented. The network node comprises an obtaining module configured to obtain, from a terminal device to which the network node provides network access, configuration information, wherein. The configuration information specifies that the terminal device needs to evaluate different polarization states during the beam management procedure with different time units. The network node comprises a beam management module configured to perform, with the terminal device, a beam management procedure. The beam management procedure involves that the network node transmits reference signals per time slot according to a reference signal transmission scheme. The reference signal transmission scheme depends on the obtained configuration information.

[0015] According to a fourth aspect, a computer program for performing a beam management procedure is presented. The computer program comprises computer program code which, when run on processing circuitry of a network node, causes the network node to perform the method according to the first aspect.

[0016] According to a fifth aspect, a method for performing a beam management procedure is presented. The method is performed by a terminal device. The method comprises providing, to a network node, configuration information, the network node providing network access to the terminal device. The configuration information specifies that the terminal device needs to evaluate different polarization states during the beam management procedure with different time units. The method comprises performing, with the network node, a beam management procedure. The beam management procedure involves that the terminal device receives reference signals per time slot from the network node according to a reference signal reception scheme. The reference signal reception scheme depends on the provided configuration information.

[0017] According to a sixth aspect, there is presented a terminal device for performing a beam management procedure. The terminal device comprises processing circuitry. The processing circuitry is configured to cause the terminal device to provide configuration information to a network node, which provides network access to the terminal device. The configuration information specifies that the terminal device needs to evaluate different polarization states at different time units during the beam management procedure. The processing circuitry is configured to cause the terminal device to perform a beam management procedure with the network node. The beam management procedure involves the terminal device receiving reference signals from the network node per time slot according to a reference signal reception scheme. The reference signal reception scheme depends on the provided configuration information.

[0018] According to a seventh aspect, there is presented a terminal device for performing a beam management procedure. The terminal device comprises a providing module configured to provide configuration information to a network node, which provides network access to the terminal device. The configuration information specifies that the terminal device needs to evaluate different polarization states at different time units during the beam management procedure. The terminal device comprises a beam management module configured to perform a beam management procedure with the network node. The beam management procedure involves the terminal device receiving reference signals from the network node per time slot according to a reference signal reception scheme. The reference signal reception scheme depends on the provided configuration information.

[0019] According to an eighth aspect, there is presented a computer program for performing a beam management procedure, the computer program comprising computer program code which, when run on processing circuitry of a terminal device, causes the terminal device to perform the method according to the fifth aspect.

[0020] According to a ninth aspect, there is presented a computer program product comprising a computer program according to at least one of the fourth and eighth aspects and a computer readable storage medium on which the computer program is stored. The computer readable storage medium can be a non-transitory computer readable storage medium.

[0021] Advantageously, these aspects enable a beam management procedure to take into account antenna architectures at the terminal device.

[0022] Advantageously, these aspects improve a beam management procedure.

[0023] Advantageously, these aspects improve a beam management procedure by enabling improvements in beam selection at the terminal device.

[0024] Other objectives, features and advantages of the enclosed embodiments will be apparent from the following detailed disclosure, from the attached claims as well as from the accompanying drawings.

[0025] In general, unless otherwise expressly defined herein, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field. Unless expressly stated otherwise, all references to "a / an / the element, device, component, part, module, step, etc." should be interpreted openly to refer to at least one instance of an element, device, component, part, module, step, etc. Unless expressly stated otherwise, the steps of any method disclosed herein do not have to be performed in the exact order disclosed. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will now be described by way of example with reference to the accompanying drawings, in which:

[0027] Figure 1 is a schematic diagram illustrating a communication network according to an embodiment;

[0028] Figure 2 schematically illustrates an antenna architecture of a terminal device according to an embodiment;

[0029] Figure 3 schematically illustrates a beam management process according to an embodiment;

[0030] Figure 4 and Figure 5 is a flow chart of a method according to an embodiment;

[0031] Figure 6 and Figure 7 is a schematic illustration of transmission of a reference signal in an OFDM symbol of a time slot according to an embodiment;

[0032] Figure 8 is a schematic diagram illustrating functional units of a network node according to an embodiment;

[0033] Figure 9 is a schematic diagram of functional modules of a network node according to an embodiment;

[0034] Figure 10 is a schematic diagram showing functional units of a terminal device according to an embodiment;

[0035] Figure 11 is a schematic diagram showing functional modules of a terminal device according to an embodiment;

[0036] Figure 12 An example of a computer program product including computer readable means according to an embodiment is shown;

[0037] Figure 13 is a schematic diagram illustrating a telecommunications network connected to a host computer via an intermediary network according to some embodiments; and

[0038] Figure 14is a schematic diagram illustrating a host computer communicating via a radio base station with a terminal device over a partially wireless connection, in accordance with some embodiments. DETAILED DESCRIPTION

[0039] The present inventive concepts will now be described more fully hereinafter with reference to the accompanying drawings, in which some embodiments of the present inventive concepts are shown. The present inventive concepts 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 present inventive concepts to those skilled in the art. Like numbers refer to like elements throughout the description. Any step or feature illustrated by dashed lines should be regarded as optional.

[0040] Figure 1 is a schematic diagram illustrating a communication network 100 in which embodiments presented herein can be applied. The communication network 100 can be a third generation (3G) telecommunication network, a fourth generation (4G) telecommunication network, a fifth generation (5G) telecommunication network, or any evolution thereof, and support any 3GPP telecommunication standard, where applicable.

[0041] The communication network 100 comprises a network node 200 configured to provide network access to terminal devices, as represented by a terminal device 300, in a radio access network 110. The radio access network 110 is operatively connected to a core network 120. The core network 120 is in turn operatively connected to a service network 130, such as the Internet. Thereby, the terminal device 300 is enabled to access services of, and exchange data with, the service network 130 via the network node 200.

[0042] The network node 200 comprises a transmission and reception point (TRP) 150 co-located with, integrated with, or in operative communication with. The network node 200 (via its TRP 140) and the terminal device 300 are configured to communicate with each other in beams, one of which is illustrated with reference sign 150. In this regard, a beam that can be used as both a TX beam and an RX beam will hereinafter be simply referred to as a beam.

[0043] Examples of the network node 200 are a radio access network node, a radio base station, a base transceiver station, a Node-B, an evolved Node-B, a gNB, an access point, an access node, and a backhaul node. Examples of the terminal device 300 are a wireless device, a mobile station, a mobile phone, a handset, a wireless local loop phone, a user equipment (UE), a smart phone, a laptop computer, a tablet computer, a network-equipped sensor, a network-equipped vehicle, and a so-called Internet of Things device.

[0044] Different types of antenna arrangements can exist that are provided for the terminal device 300 in order for the terminal device 300 to effectively communicate with the TRPs 140. In this regard, an antenna panel can be defined as a rectangular array of dual-polarized antenna elements, typically with one transmit / receive unit (TXRU) per polarization. An analog distribution network with phase shifters can be used to steer the directional beams generated at each such antenna panel. Alternatively, the terminal device 300 is configured for digital wideband (time-domain beamforming) beamforming that mimics the operation and functionality of an analog distribution network. Multiple antenna panels can be stacked next to each other and digital beamforming can be performed across the antenna panels. For the terminal device 300, signals can arrive and be emitted from all different directions depending on its physical orientation. Therefore, in addition to high-gain narrow directional beams, it can be beneficial to have an antenna implementation at the terminal device 300 that enables the terminal device 300 to generate a quasi-omni coverage for the terminal device 300. One way to increase the omni coverage at the terminal device 300 is to provide the terminal device 300 with multiple antenna panels, wherein at least two of these antenna panels have different pointing directions.

[0045] Figure 2 An example antenna architecture of the terminal device 300 is schematically illustrated. According to the illustrated antenna architecture, the terminal device 300 is equipped with at least one antenna array 340a, 340b. Each antenna array 340a, 340b has dual-polarized antenna elements. In the illustrated example, each antenna array 340a, 340b has eight dual-polarized antenna elements, but as understood by the skilled person, each antenna array 340a, 340b can have less than eight dual-polarized antenna elements or more than eight dual-polarized antenna elements. The antenna arrays 340a, 340b can be connected to a baseband chain 350 in the terminal device 300 (via a switch 360). In some examples, the terminal device 300 is equipped with more than one antenna array 340a, 340b. In turn, two or more antenna arrays 340a, 340b can be selectively connected to the same baseband chain 350, one antenna array at a time. This enables the terminal device 300 to include only one single baseband chain 350, despite including two or more antenna arrays 340a, 340b. In other examples, the terminal device 200 includes two or more baseband chains 350, wherein each baseband chain 350 can be connected to one or more antenna arrays 340a, 340b. This enables each antenna array 340a, 340b to have its own baseband chain 350. The antenna architecture can be part of the communication interface 320 of the terminal device 300. Thus, in some embodiments, the terminal device 300 is equipped with an antenna array 340a, 340b with dual-polarized antenna elements, wherein the antenna array 340a, 340b is connected to a baseband chain 350 in the terminal device 300.

[0046] As disclosed above, there is still a need for improved beam management procedures. Therefore, reference is made to Figure 3 , Figure 3 The beam management procedure is schematically illustrated as consisting of three sub-procedures, referred to as P-1, P-2 and P-3 sub-procedures. The three sub-procedures will now be disclosed in more detail.

[0047] One main purpose of the P-1 sub-procedure is for the network node 200 to find a coarse direction towards the terminal device 300 by transmitting reference signals in wide but sector-narrower beams that sweep over the entire angular sector. For the P-1 sub-procedure, the TRP 140 is expected to use beams with a fairly large beamwidth according to the spatial beam pattern 160a. During the P-1 sub-procedure, the reference signals are typically transmitted periodically and shared between all terminal devices 300 served by the network node 200 in the radio access network 1 10. According to the spatial beam pattern 170a, the terminal device 300 uses a wide (or even omni-directional) beam during the P-1 sub-procedure for receiving the reference signals. The reference signals can be CSI-RSs (or formally, CSI-RS resources) or SSBs that are transmitted periodically. In turn, the terminal device 300 can report N > 1 best beams and their corresponding quality values, such as reference signal received power (RSRP) values, to the network node 200. The beam reporting from the terminal device 300 to the network node 200 can be performed rarely (in order to save overhead) and can be periodic, semi-persistent, or aperiodic.

[0048] One main purpose of the P-2 sub-procedure is to refine the beam selection at the TRP 140 by the network node 200 transmitting reference signals when performing a new beam sweep with narrower (compared to those used during the P-1 sub-procedure) directional beams according to the spatial beam pattern 160b, wherein the new beam sweep is performed around the coarse direction or beam reported during the P-1 sub-procedure. During the P-2 sub-procedure, the terminal device 300 typically uses the same beams as during the P-1 sub-procedure according to the spatial beam pattern 170b. In turn, the terminal device 300 can report N > 1 best beams and their corresponding quality values, such as reference signal received power (RSRP) values, to the network node 200. One P-2 sub-procedure can be performed per terminal device 300 or per terminal device 300 group. The reference signals can be CSI-RSs (or formally, CSI-RS resources) that are transmitted aperiodically or semi-persistently. In order to track the movement of the terminal device 300 and / or changes in the radio propagation environment, the P-2 sub-procedure can be performed more frequently than the P-1 sub-procedure.

[0049] One main purpose of the P-3 sub-process is for the terminal device 300 to find the best beam using analog beamforming or digital wideband (time-domain beamforming) beamforming. During the P-3 sub-process, while the terminal device 300 performs beam sweeping according to the spatial beam pattern 170c, the reference signal is transmitted in the best reported beam according to the spatial beam pattern 160c of the P-2 sub-process. In order for the terminal device 300 to be able to compensate for blockage and / or rotation, the P-3 sub-process can be performed at least as frequently as the P-2 sub-process.

[0050] Due to the physical radio environment, which beam is reported as the best beam can differ for different polarizations. For example, for certain non-line-of-sight (NLOS) radio propagation environments, a beam reported as the strongest beam in one polarization can correspond to the weakest beam in the orthogonal polarization. One way to mitigate this is to switch the polarization of the beams at the TRP 140 between successive SSB transmissions. However, such switching can cause problems for automatic gain control (AGC) as performed by the terminal device 300. One reason for this is that the received power of the two reference signals transmitted for the two orthogonal polarizations can differ too much, e.g., by more than 10 dB.

[0051] Instead of using the P-3 sub-process, one alternative way for the terminal device 300 to find its best beam is for the terminal device 300 to evaluate different beams during periodic SSB transmissions after initial network access. Since each SSB consists of four orthogonal frequency-division multiplexing (OFDM) symbols, up to four beams can be evaluated during each SSB burst transmission. One benefit of doing this is that there is no additional CSI-RS transmission overhead. However, one drawback of determining the beam to use at the terminal device 300 based on SSB transmissions is that SSBs only have one TRP port and are therefore transmitted through only one polarization (per each unique direction), which means that the terminal device 300 can only be able to evaluate suitable beams for one polarization. However, as disclosed above, if the RSRP differs significantly for different polarizations, there is a risk that a non-optimal beam is selected at the terminal device 300.

[0052] Accordingly, embodiments disclosed herein relate to mechanisms for performing a beam management procedure. To obtain such mechanisms, there is provided a network node 200, a method performed by the network node 200, a computer program product comprising code e.g. in the form of a computer program that, when run on processing circuitry of the network node 200, causes the network node 200 to perform the method. To obtain such mechanisms, there is further provided a terminal device 300, a method performed by the terminal device 300, and a computer program product comprising code e.g. in the form of a computer program that, when run on processing circuitry of the terminal device 300, causes the terminal device 300 to perform the method.

[0053] Reference will now be made to Figure 4 , Figure 4 Fig. illustrates a method for performing a beam management procedure as performed by a network node 200 according to embodiments.

[0054] The network node 200 will perform a beam management procedure that depends on the information of the terminal device 200. Accordingly, the network node 200 is configured to perform step S102:

[0055] S102: The network node 200 obtains configuration information from terminal devices 300 to which the network node 200 provides network access. The configuration information specifies that different polarization states need to be evaluated by the terminal devices 300 at different time units during the beam management procedure.

[0056] Further, the obtained information is used when performing the beam management procedure. In particular, the network node 200 is configured to perform step S104:

[0057] S104: The network node 200 performs a beam management procedure with the terminal device 300. The beam management procedure involves that the network node 200 transmits reference signals per time slot according to a reference signal transmission scheme. The reference signal transmission scheme depends on the obtained configuration information.

[0058] Embodiments relating to further details of performing a beam management procedure as performed by a network node 200 will now be disclosed.

[0059] Each reference signal can correspond to a respective CSI-RS resource or SSB.

[0060] There can be different types of reference signal transmission schemes. In some aspects, the reference signal transmission scheme defines where in a time slot the reference signals are to be transmitted. In particular, in some embodiments where each of the different time units corresponds to a respective OFDM symbol, the reference signal transmission scheme defines at which OFDM symbols of each time slot the reference signals are to be transmitted.

[0061] Some embodiments will now be disclosed according to which the amount of reference signals to be transmitted can be adapted according to configuration information. In some aspects, these embodiments can easily be combined with the P-2 sub-process described above. Reference is also made to Figure 6 Other aspects related thereto are disclosed.

[0062] In some aspects, the total amount of reference signals to be transmitted per time slot is equal to twice the number of beams in which the reference signals are to be transmitted at the TRP 140. That is, according to embodiments, the reference signals are to be transmitted in beams according to the beam management procedure, and each reference signal is to be transmitted in each beam twice per time slot according to the reference signal transmission scheme.

[0063] The embodiments described above enable the terminal device 300 to measure the RSRP of each beam at the terminal device 300 for both polarizations during the beam sweeping of the P-2 sub-process. This can be achieved by transmitting the CSI-RS resources twice in each beam at the TRP 140.

[0064] Some embodiments will now be disclosed according to which the positions in time slots in which the reference signals are placed can be adapted according to configuration information. In some aspects, these embodiments can easily be combined with the P-3 sub-process described above. Reference is also made to Figure 7 Other aspects related thereto are disclosed.

[0065] In some aspects, the terminal device 300 is configured to use N > 1 beams per polarization. Thus, in some embodiments, the configuration information further specifies that the terminal device 300 is configured to generate N > 1 beams per polarization of antenna elements. However, this does not mean that the terminal device 300 is actually to generate all N beams during the beam management procedure, only that the terminal device 300 is configured to generate these beams.

[0066] In some aspects, the number of reference signals to be transmitted per time slot as part of the beam management procedure depends on the value of N. Specifically, in some embodiments, how many reference signals are to be transmitted per time slot depends on the value of N. In this regard, according to a first example, the total number of reference signals to be transmitted per time slot as part of the beam management procedure is less than 2 · N. That is, in some embodiments, according to the reference signal transmission scheme, less than 2 · N reference signals are to be transmitted per time slot. According to a second example, the total number of reference signals to be transmitted per time slot as part of the beam management procedure is equal to N + 2. That is, in some embodiments, according to the reference signal transmission scheme, exactly N + 2 reference signals are to be transmitted per time slot.

[0067] In some aspects, two of the reference signals are spaced apart in time from the remaining reference signals in the time slot. That is, in some embodiments, two of the reference signals are spaced apart from the remaining N reference signals in the time slot by at least one OFDM symbol according to the reference signal transmission scheme, and the two reference signals are to be transmitted before the remaining N reference signals.

[0068] There are different ways to temporally separate two of the reference signals from the remaining reference signals in a time slot. In some aspects, the two reference signals are placed first in a time slot, while the remaining reference signals are placed last in the same time slot. That is, in some embodiments, two of the reference signals are placed to be transmitted as early as possible in a time slot, and the remaining N reference signals are placed to be transmitted as late as possible in the same time slot, depending on the reference signal transmission scheme.

[0069] In some aspects, all reference signals are sent using the same beam. That is, in some embodiments, all reference signals per time slot are sent using the same beam (as generated at TRP 140).

[0070] The above embodiment enables the terminal device 300 to first evaluate the preferred polarization during the beam scanning of the P-3 sub-process, and then evaluate the preferred narrow beam for the preferred polarization. This can be achieved by adapting the position of the CSI-RS resource in the time slot at the network node 200.

[0071] Now refer to Figure 5 , Figure 5 A method for performing a beam management procedure as performed by the terminal device 300 according to an embodiment is illustrated.

[0072] As disclosed above, the network node 200 will perform a beam management process that depends on the information of the terminal device 200. Therefore, the terminal device 300 is configured to perform step S202:

[0073] S202: The terminal device 300 provides configuration information to the network node 200, and the network node 200 provides network access to the terminal device 300. The configuration information specifies that the terminal device 300 needs to evaluate different polarization states in different time units during the beam management process.

[0074] The provided information is then used when performing the beam management process. Specifically, the terminal device 300 is configured to perform step S204:

[0075] S204: The terminal device performs a beam management procedure with the network node 200. The beam management procedure involves the terminal device 300 receiving reference signals from the network node 200 per time slot according to a reference signal reception scheme. The reference signal reception scheme depends on the provided configuration information.

[0076] Although the reference signal reception scheme can be considered to be prescribed based on information received from the network node 200, the reference signal reception scheme itself need not be signalled from the network node 200 to the terminal device 300. Instead, the reference signal reception scheme is defined by the way in which the terminal device 300 operates.

[0077] Embodiments relating to further details of performing a beam management procedure, as performed by the terminal device 300, will now be disclosed.

[0078] There can be different types of reference signal reception schemes. In some aspects, the reference signal reception scheme defines where in a time slot reference signals are to be received. In particular, in some embodiments in which each of the different time units corresponds to a respective OFDM symbol, the reference signal reception scheme defines which OFDM symbols per time slot reference signals are to be received at.

[0079] Some embodiments according to which the amount of reference signals to be transmitted, and thus the amount of reference signals to be received by the terminal device 300, can be adapted according to the configuration information will now be disclosed. In some aspects, these embodiments can easily be combined with the P-2 sub procedure described above. Reference is also made to the above description of the P-2 sub procedure. Figure 6 Further aspects relating thereto are disclosed.

[0080] As disclosed above, in some aspects, the total amount of reference signals to be transmitted per time slot is equal to twice the number of beams in which reference signals are to be transmitted at the TRP 140. Thus, half of the reference signals can be received in each polarization. That is, in some embodiments, when performing the beam management procedure, half of the reference signals are received using a first polarization, while the remaining half of the reference signals are received using a second polarization. Furthermore, as disclosed above, according to the beam management procedure, reference signals can be transmitted in beams. In turn, according to the reference signal reception scheme, each reference signal per beam and per time slot can be received once using a first polarization and once using a second polarization. In this regard, the terminal device 300 can be informed about which reference signals are transmitted in the same beam and which reference signals are transmitted in different beams.

[0081] The above-described embodiments enable the terminal device 300 to measure the RSRP for each beam at the terminal device 300 for both polarizations during the beam sweeping of the P-2 sub procedure.

[0082] Now, some embodiments will be disclosed according to which it can be adapted according to the configuration information which positions of the reference signals in the time slot are placed. In some aspects, these embodiments can easily be combined with the above described P-3 sub-process. Reference is also made to Figure 7 Other aspects related thereto are disclosed.

[0083] As disclosed above, in some embodiments, the configuration information further specifies that the terminal device 300 is configured to generate N > 1 beams per polarization of antenna elements.

[0084] As disclosed above, in some embodiments, how many reference signals per time slot are to be received depends on N.

[0085] As disclosed above, according to the first example, the total number of reference signals per time slot to be transmitted as part of the beam management procedure is less than 2-N. Thus, in some embodiments, according to the reference signal reception scheme, less than 2-N reference signals per time slot are to be received. As further disclosed above, according to the second example, the total number of reference signals per time slot to be transmitted as part of the beam management procedure is equal to N+2. Thus, in some embodiments, according to the reference signal reception scheme, exactly N+2 reference signals per time slot are to be received.

[0086] As disclosed above, two of these reference signals can be spaced in time from the remaining reference signals in the time slot. Thus, in some embodiments, according to the reference signal reception scheme, two of these reference signals are spaced at least one OFDM symbol from the remaining N reference signals in the time slot, and these two reference signals are to be received before the remaining N reference signals.

[0087] As disclosed above, the two reference signals can be placed first in the time slot, while the remaining reference signals can be placed last in the same time slot. Thus, in some embodiments, according to the reference signal reception scheme, two of these reference signals are placed to be received as early as possible in the time slot, and wherein the remaining N reference signals are placed to be received as late as possible in the same time slot.

[0088] In some aspects, the terminal device 300 first evaluates the preferred polarization, and then uses the best polarization when receiving the remaining reference signals. When evaluating the preferred polarization, the terminal device 300 can use one or more beams that are wider compared to the one or more beams used for receiving the remaining reference signals. This is also in line with the above described P-3 sub-process. Figure 7Specifically, in some embodiments, when performing a beam management process, the RSRP of a first reference signal received using a first polarization among two of the reference signals is compared with the RSRP of a second reference signal received using a second polarization among the two of the reference signals, and the remaining N reference signals are received using the polarization (of the first polarization and the second polarization) that yields the highest RSRP.

[0089] The above-described embodiment enables the terminal device 300 to first evaluate the preferred polarization during the beam scanning of the P-3 sub-process, and then evaluate the preferred narrow beam for the preferred polarization.

[0090] Now, one example of how some embodiments disclosed herein can be easily combined with the above-described P-2 sub-process will be disclosed.

[0091] Since the network node 200 obtains configuration information from the terminal device 300, wherein the configuration information specifies that the terminal device 300 needs to evaluate different polarization states at different time units during the beam management process, the network node 200 can schedule a P2 sub-process according to which beam scanning is performed so that the terminal device 300 can evaluate the reference signal sent in each beam for both the first polarization and the second polarization at the terminal device 300. This can be achieved, for example, by the network node 200 scheduling the transmission of the reference signal in the beam (by repeating the CSI-RS resource transmission twice in each beam). This enables the terminal device 300 to receive the reference signal sent in each beam first using the first polarization and then using the second polarization (or vice versa). This is in Figure 6 In more detail, Figure 6 The diagram illustrates the transmission of reference signals in OFDM symbols of a time slot 600, as well as beams 630 used by the TRP 140 to transmit reference signals and beams 640 used by the terminal device 300 to receive reference signals. The time slot 600 consists of 14 OFDM symbols 610, 620. The last six OFDM symbols (one of which is identified by reference numeral 620) contain CSI-RS resources (used for beam management), while the remaining OFDM symbols (one of which is identified by reference numeral 610) do not contain any CSI-RS resources (used for beam management). Figure 6 , enabling the terminal device 300 to evaluate three different beams in which reference signals are transmitted. These reference signals are transmitted twice per beam, so that each of the three beams can be evaluated in each of the first and second polarizations at the terminal device 300. This improves beam selection at the TRP 140 because the risk of polarization mismatch is reduced.

[0092] Now, one example will be disclosed how some of the embodiments disclosed herein can easily be combined with the above described P-3 sub-process.

[0093] As the network node 200 obtains configuration information from the terminal device 300, wherein the configuration information specifies that the terminal device 300 needs to evaluate different polarization states at different time units during the beam management procedure, the network node 200 can schedule the P3 sub-process according to which the terminal device 300 is enabled to first evaluate the preferred polarization state and in turn perform beam sweeping for the preferred polarization state. This is schematically illustrated in Figure 7 Fig. 6. In more detail, Figure 7 transmission of reference signals in OFDM symbols of a time slot 700 and beams 730, 740 used by the terminal device 300 for receiving the reference signals are illustrated. The time slot 700 consists of 14 OFDM symbols 710, 720. The first two OFDM symbols and the last four OFDM symbols, one of which is identified with reference 720, contain CSI-RS resources (for beam management), while the remaining OFDM symbols, one of which is identified with reference 710, do not contain any CSI-RS resources (for beam management). For the reception of the first two CSI-RS resources, the terminal device 300 generates two wide beams 730 which are polarized orthogonal to each other (defined by a first polarization and a second polarization). Based on the RSRP measurements of the first two CSI-RS resources, the terminal device 300 determines which polarization is preferred. In Figure 7 the illustrative example of Fig. 6, it is assumed that the first polarization yields the highest RSRP and thus represents the preferred polarization. When receiving the last four OFDM symbols containing CSI-RS resources, the terminal device 300 sweeps through four narrow beams 740 in this preferred polarization.

[0094] Figure 8 The components of the network node 200 according to an embodiment are schematically illustrated in terms of a number of functional units. The processing circuitry 210 is provided using any combination of one or more of a suitable central processing unit (CPU), multiprocessor, microcontroller, digital signal processor (DSP), etc., capable of executing software instructions stored in a computer program product 1210a (for example in the form of a storage medium 230). The processing circuitry 210 can further be provided as at least one application-specific integrated circuit (ASIC), or field programmable gate array (FPGA). Figure 12

[0095] ​In particular, the processing circuitry 210 is configured to cause the network node 200 to perform a set of operations or steps as disclosed above. For example, the storage medium 230 can store the set of operations, and the processing circuitry 210 can be configured to retrieve the set of operations from the storage medium 230 to cause the network node 200 to perform the set of operations. The set of operations can be provided as a set of executable instructions. Thus, the processing circuitry 210 is thereby arranged to perform the methods as herein disclosed.

[0096] The storage medium 230 can further include a permanent storage, which, for example, can be any one or combination of a magnetic storage, optical storage, solid state storage, or even remotely mounted storage.

[0097] The network node 200 can further include a communication interface 220 for communicating with other entities, functions, nodes and devices of the communication network 100, and with entities, functions, nodes and devices operably connected to or served by the communication network 100. The communication interface 220 can thereby include one or more transmitters and receivers, including analog and digital components.

[0098] The processing circuitry 210 controls the general operation of the network node 200, e.g. by sending data and control signals to the communication interface 220 and the storage medium 230, receiving data and reports from the communication interface 220, and retrieving data and instructions from the storage medium 230. Other components and the related functionality of the network node 200 are omitted in order not to obscure the concepts presented herein.

[0099] Figure 9 The components of the network node 200 according to embodiments are schematically illustrated in relation to a number of functional modules. Figure 9 The network node 200 of Fig. 2 comprises a number of functional modules: an obtaining module 210a configured to perform step S102, and a beam management module 210b configured to perform step S104. Figure 9 The network node 200 of Fig. 2 can further comprise a number of optional functional modules, such as represented by functional module 210c. In general terms, each functional module 210a-210c can be implemented in hardware or in software. Preferably, one or more or all functional modules 210a-210c can be implemented by the processing circuitry 210, possibly in cooperation with the communication interface 220 and / or the storage medium 230. The processing circuitry 210 can thereby be arranged to retrieve instructions from the storage medium 230 as provided by the functional modules 210a-210c and execute these instructions, thereby performing any of the steps of the network node 200 as herein disclosed.

[0100] The network node 200 can be provided as a standalone device or as part of at least one other device. For example, the network node 200 can be provided in a node of the radio access network 110 or in a node of the core network 120. Alternatively, the functionality of the network node 200 can be distributed between at least two devices or nodes. The at least two nodes or devices can be part of the same network, such as the radio access network 110 or the core network 120, or can stretch across at least two such networks. Generally, instructions that need to be executed in real-time can be executed in a device or node that is operationally closer to the cell compared to instructions that do not need to be executed in real-time. In this regard, at least part of the network node 200 can reside in the radio access network, such as in a radio access network node, for cases when the instructions as disclosed herein are executed in real-time.

[0101] Thus, a first part of the instructions executed by the network node 200 can be executed in a first device and a second part of the instructions executed by the network node 200 can be executed in a second device; the embodiments disclosed herein are not limited to any particular number of devices on which the instructions executed by the network node 200 can be executed. Thus, the methods according to the embodiments disclosed herein are applicable to be executed by the network node 200 residing in a cloud computing environment. Thus, although a single processing circuit 210 is illustrated in Figure 8 The processing circuit 210 can be distributed between multiple devices or nodes. The same applies to the functional modules 210a-210c of the network node 200 and the computer program 1220a of the network node 200. Figure 9 The processing circuit 210 can be distributed between multiple devices or nodes. The same applies to the functional modules 210a-210c of the network node 200 and the computer program 1220a of the network node 200. Figure 12 The processing circuit 210 can be distributed between multiple devices or nodes. The same applies to the functional modules 210a-210c of the network node 200 and the computer program 1220a of the network node 200.

[0102] Figure 10 The components of the terminal device 300 according to the embodiments are schematically illustrated in terms of a number of functional units. One or more of any combination of suitable central processing units (CPUs), multiprocessors, microcontrollers, digital signal processors (DSPs), etc., using software instructions stored in the computer program product 1210b, e.g. in the form of a storage medium 330, are provided for the processing circuit 310. The processing circuit 310 can further be provided as at least one application-specific integrated circuit (ASIC), or field-programmable gate array (FPGA). Figure 12 The processing circuit 310 can be distributed between multiple devices or nodes. The same applies to the functional modules 310a-310c of the terminal device 300 and the computer program 1220b of the terminal device 300.

[0103] In particular, the processing circuitry 310 is configured to cause the terminal device 300 to perform a set of operations or steps as disclosed above. For example, the storage medium 330 can store the set of operations, and the processing circuitry 310 can be configured to retrieve the set of operations from the storage medium 330 to cause the terminal device 300 to perform the set of operations. The set of operations can be provided as a set of executable instructions. Hence, the processing circuitry 310 is thereby arranged to perform methods as disclosed herein.

[0104] The storage medium 330 can further include a persistent storage, which, for example, can be any one or combination of a magnetic storage, optical storage, solid state storage, or even remotely mounted storage.

[0105] The terminal device 300 can further include a communication interface 320 for communicating with the network node 200 at least via the TRP 140. Hence, the communication interface 320 can comprise one or more transmitters and receivers, comprising analog and digital components. In this regard, the communication interface 320 can comprise, or be operatively connected to, an antenna architecture as described above with reference to the network node 200. Figure 2

[0106] The processing circuitry 310 controls the general operation of the terminal device 300, e.g. by sending data and control signals to the communication interface 320 and the storage medium 330, by receiving data and reports from the communication interface 320, and by retrieving data and instructions from the storage medium 330. In order not to obscure the concepts presented herein, no further details of the terminal device 300 and its components are given.

[0107] Figure 11 The components of the terminal device 300 according to embodiments are schematically illustrated in terms of a number of functional modules. Figure 11 The terminal device 300 of Fig. 2 comprises a number of functional modules: a providing module 310a configured to perform step S202; and a beam management module 310b configured to perform step S204. Figure 11 The terminal device 300 of Fig. 2 can further comprise a number of optional functional modules, as represented by functional module 310c. In general terms, each functional module 310a-310c can be implemented in hardware or in software. Preferably, one or more or all functional modules 310a-310c can be implemented by the processing circuitry 310, possibly in cooperation with the communication interface 320 and / or the storage medium 330. The processing circuitry 310 can thus be arranged to retrieve instructions provided by the functional modules 310a-310c from the storage medium 330 and execute these instructions, thereby performing any steps of the terminal device 300 as disclosed herein.

[0108] Figure 12 ​One example of a computer program product of a computer program 1210a, 1210b comprising computer readable storage medium 1230 is shown. On this computer readable medium 1230, a computer program 1220a can be stored, which computer program 1220a can cause the processing circuitry 210 and thereto operatively coupled entities and devices, such as the communication interface 220 and the storage medium 230, to execute methods according to embodiments described herein. The computer program 1220a and / or computer program product 1210a can thus provide means for performing any steps of methods of a network node 200 as disclosed herein. On this computer readable medium 1230, a computer program 1220b can be stored, which computer program 1220b can cause the processing circuitry 310 and thereto operatively coupled entities and devices, such as the communication interface 320 and the storage medium 330, to execute methods according to embodiments described herein. The computer program 1220b and / or computer program product 1210b can thus provide means for performing any steps of methods of a terminal device 300 as disclosed herein.

[0109] In Figure 12 The computer program product 1210a, 1210b is in the examples shown embodied as a disc, such as a CD (compact disc) or a DVD (digital versatile disc) or a Blu-Ray disc. The computer program product 1210a, 1210b can also be embodied as a memory, such as a random access memory (RAM), a read only memory (ROM), an erasable programmable read only memory (EPROM), or an electrically erasable programmable read only memory (EEPROM) and more particularly a nonvolatile memory in an

[0110] Figure 13 is a schematic diagram illustrating a telecommunication network connected via an intermediate network 420 to a host computer 430, according to some embodiments. The communication system includes a telecommunication network 410, such as a 3GPP-type cellular network, which comprises an access network 411, such as a Figure 1 wireless access network 110 in Figure 1 wireless access network 110 in Figure 1wireless access points, each radio access network node defining a corresponding coverage area or cell 413a, 413b, 413c. Each radio access network node 412a, 412b, 412c can be connected to a core network 414, either directly or via wired or wireless connection 415. A first UE 491 located in coverage area 413c is configured to wirelessly connect to, or be paged by, the corresponding network node 412c. A second UE 492 in coverage area 413a is wirelessly connected to the corresponding network node 412a. While a plurality of UEs 491, 492 are illustrated in this example, the disclosed embodiments are equally applicable to a situation where only a single UE is in a coverage area or where a single terminal device is connecting to a corresponding network node 412. UEs 491, 492 correspond to Figure 1 terminal device 300.

[0111] The telecommunication network 410 is itself connected to a host computer 430, which can be embodied in hardware and / or software and can be embodied as a standalone server, a cloud-implemented server, a distributed server, or a combination thereof. The host computer 430 can be controlled by a service provider or be operated by a service provider. Connections 421 and 422 between the telecommunication network 410 and the host computer 430 can be direct or indirect connections. The intermediate network 420 can be one of, or a combination of, public, proprietary, or host-based networks. The intermediate network 420 can be a backbone network or the Internet. In particular, the intermediate network 420 can include one or more wired and / or wireless networks, one or more private networks, and / or one or more public networks. Connections 421 and 422 can be optical, wired, and / or wireless connections.

[0112] Figure 13The communication system as a whole enables connectivity between the connected UEs 491, 492 and the host computer 430. The connectivity can be described as an over-the-top (OTT) connection 450. The host computer 430 and the connected UEs 491, 492 are configured to communicate data and / or signaling over the OTT connection 450 using the access network 411, the core network 414, any intermediate network 420 and possible further infrastructure (not shown) as intermediaries. The OTT connection 450 can be transparent in the sense that the participating communication devices through which the OTT connection 450 passes are unaware of the routing of uplink and downlink communications. For example, a network node 412 can not or need not be informed about the past routing of an incoming downlink communication with data originating from a host computer 430 to be forwarded (e.g., handed over) to a connected UE 491. Similarly, the network node 412 need not be aware of the future routing of an outgoing uplink communication originating with the UE 491 to be forwarded (e.g., handed over) to the host computer 430.

[0113] Figure 14 is a schematic diagram illustrating a host computer communicating via a radio access network node with a UE over a partially wireless connection, in accordance with some embodiments. An example implementation, in accordance with an embodiment, of the UE, the radio access network node, and the host computer discussed in the preceding paragraph will now be described with reference to Figure 14 The communication system 500 in Figure 5 hosts the UE 530, the radio access network node 412, and the host computer 510 involved in the OTT connection 550. These three entities can be unaware of each other and can not directly interact with each other. For instance, they can not be in the same network or operated by the same operator. They can interact with each other via the OTT connection 550 using the Internet as intermediary. Figure 1 The host computer 510 can comprise a processing system 515 configured to provide services to the UE 530 via the OTT connection 550. The processing system 515 can be implemented in hardware, software, or a combination thereof. The host computer 510 further comprises a communication interface 516 that is configured to set up and maintain the OTT connection 550 with the UE 530. The host computer 510 further comprises a storage medium 517 that is configured to store data and / or instructions used by the processing system 515, such as for example a host application 512 that provides services to the UE 530. The host computer 510 further comprises a scheduler 519 that is configured to perform scheduling of services to be provided to the UE 530.

[0114] The communication system 500 further comprises a radio access network node 520 provided in the telecommunication system and comprising hardware 525 enabling it to communicate with the host computer 510 and the UE 530. The radio access network node 520 corresponds to Figure 1 The hardware 525 may include a communication interface 526 for establishing and maintaining a wired or wireless connection with different communication devices of the communication system 500, and a communication interface 526 for establishing and maintaining a connection with at least a network device located in a coverage area served by the radio access network node 520 (not in the coverage area). Figure 14 The communication interface 526 may be configured to facilitate a connection 560 to the host computer 510. The connection 560 may be direct, or it may pass through a core network (not shown in FIG. 1 ) in the telecommunications system. Figure 14 ) and / or through one or more intermediate networks external to the telecommunications system. In the illustrated embodiment, the hardware 525 of the radio access network node 520 further includes processing circuitry 528, which may include one or more programmable processors, application specific integrated circuits, field programmable gate arrays, or a combination of these components (not shown) suitable for executing instructions. The radio access network node 520 further has software 521 that is stored internally or accessible via an external connection.

[0115] The communication system 500 further includes the aforementioned UE 530. Its hardware 535 may include a radio interface 537 configured to establish and maintain a wireless connection 570 with a radio access network node serving the coverage area currently located by the UE 530. The hardware 535 of the UE 530 further includes processing circuitry 538, which may include one or more programmable processors, application-specific integrated circuits, field-programmable gate arrays, or a combination of these components (not shown) suitable for executing instructions. The UE 530 further includes software 531, which is stored in or accessible by the UE 530 and executable by the processing circuitry 538. The software 531 includes a client application 532. The client application 532 may be operable with the support of the host computer 510 to provide services to human or non-human users via the UE 530. In the host computer 510, the executing host application 512 may communicate with the executing client application 532 via an OTT connection 550 terminated between the UE 530 and the host computer 510. When providing services to users, client application 532 can receive request data from host application 512 and provide user data in response to the request data. OTT connection 550 can transmit both the request data and the user data. Client application 532 can interact with the user to generate the user data it provides.

[0116] It should be noted that the host computer 510, the radio access network node 520, and the UE 530 illustrated in Figure 14 may be similar or identical to the host computer 430, one of the network nodes 412a, 412b, 412c, and one of the UEs 491, 492 of Figure 13 , respectively. This is to say, the inner workings of these entities can be as shown in Figure 14 and independently, the surrounding network topology can be as shown in Figure 13 .

[0117] In Figure 14 , the OTT connection 550 has been drawn abstractly to illustrate the communication between the host computer 510 and the UE 530 via the network node 520, without explicit reference to any intermediary devices and the precise routing of messages via these devices. Network infrastructure can determine the routing, which it can be configured to hide from the UE 530 or from the service provider operating the host computer 510, or both. While the OTT connection 550 is active, the network infrastructure can further take decisions that cause it to dynamically change the routing (e.g., on the basis of load balancing consideration or reconfiguration of the network).

[0118] The wireless connection 570 between the UE 530 and the radio access network node 520 is in accordance with the teachings of the embodiments described in this disclosure. One or more of the various embodiments can improve the performance of OTT services provided to the UE 530 using the OTT connection 550 of which the wireless connection 570 forms the last segment. More precisely, the teachings of these embodiments can reduce interference due to improved categorization capabilities of the on-board UE.

[0119] A measurement procedure can be provided for the purpose of monitoring the data rate, the latency, and other factors on which one or more embodiments have impact. There can further be an optional network functionality for reconfiguring the OTT connection 550 between the host computer 510 and the UE 530, in response to variations in the measurement results. The measurement procedure and / or the network functionality for reconfiguring the OTT connection 550 can be implemented in the software 511 and the hardware 515 of the host computer 510 or in the software 531 and the hardware 535 of the UE 530, or both. In embodiments, sensors (not shown) can be deployed in or in association with communication devices through which the OTT connection 550 passes; the sensors can participate in the measurement procedure by providing values of the monitored quantities exemplified above, or providing values of other physical quantities from which the software 511, 531 can compute or estimate the monitored quantities. The reconfiguring of the OTT connection 550 can include message format, retransmission settings, preferred routing, etc.; the reconfiguring need not affect the radio access network 520, and it can be unknown or invisible to the radio access network 520. Such procedures and functionalities can be known and practiced in the art. In certain embodiments, the measurements can involve proprietary UE signaling facilitating the host computer's 510 measurements of throughput, propagation times, latency, and the like. The measurements can be implemented at least in part by the software 511, 531 causing messages to be transmitted, in particular empty or 'dummy' messages, using the OTT connection 550, and measuring propagation times, errors, and so on.

[0120] The inventive concept has mainly been described above with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the inventive concept, as defined by the appended claims.

Claims

1. A method for performing a beam management process, the method being performed by a network node (200), the method comprising: obtaining (S102) configuration information from a terminal device (300) to which the network node (200) provides network access, wherein the configuration information specifies that the terminal device (300) needs to evaluate different polarization states at different time units during the beam management process; and Performing (S104) the beam management process with the terminal device (300), wherein the beam management process involves the network node (200) transmitting a reference signal per time slot according to a reference signal transmission scheme, and wherein the reference signal transmission scheme depends on the obtained configuration information.

2. The method according to claim 1, wherein Each of the different time units corresponds to a respective OFDM symbol, and wherein the reference signal transmission scheme defines at which OFDM symbols per slot the reference signal is to be transmitted.

3. The method according to claim 1 or 2, wherein: According to the beam management procedure, the reference signals are to be transmitted in beams, and wherein, according to the reference signal transmission scheme, each reference signal is to be transmitted twice in each beam per time slot.

4. The method according to claim 1 or 2, wherein: The configuration information further specifies that the terminal device (300) is configured to generate N>1 beams for each polarization of the antenna elements.

5. The method according to claim 4, wherein The number of reference signals to be sent per slot depends on N.

6. The method according to claim 4, wherein: According to the reference signal transmission scheme, less than 2N reference signals will be transmitted per time slot.

7. The method according to claim 4, wherein: According to the reference signal transmission scheme, exactly N+2 reference signals will be transmitted per time slot.

8. The method according to claim 4, wherein According to the reference signal transmission scheme, two of the reference signals are separated from the remaining N reference signals in the time slot by at least one OFDM symbol, and wherein the two of the reference signals are to be transmitted before the remaining N reference signals.

9. The method according to claim 8, wherein According to the reference signal transmission scheme, two of the reference signals are placed to be transmitted as early as possible in the time slot, and wherein the remaining N reference signals are placed to be transmitted as late as possible in the time slot.

10. The method according to claim 4, wherein: All the reference signals in each time slot will be sent using the same beam.

11. A method for performing a beam management process, the method being performed by a terminal device (300), the method comprising: providing (S202) configuration information to a network node (200) that provides network access to the terminal device (300), wherein the configuration information specifies that the terminal device (300) needs to evaluate different polarization states at different time units during the beam management process; and Performing (S204) the beam management process with the network node (200), wherein the beam management process involves the terminal device (300) receiving a reference signal from the network node (200) per time slot according to a reference signal reception scheme, and wherein the reference signal reception scheme depends on the provided configuration information.

12. The method according to claim 11, wherein Each of the different time units corresponds to a respective OFDM symbol, and wherein the reference signal reception scheme defines at which OFDM symbols per time slot the reference signal is to be received.

13. The method according to claim 11 or 12, wherein: When the beam management process is performed, half of the reference signals are received using a first polarization, and the remaining half of the reference signals are received using a second polarization.

14. The method according to claim 13, wherein According to the beam management procedure, the reference signal is to be transmitted in a beam, and wherein, according to the reference signal reception scheme, each reference signal per beam is to be received once per time slot using the first polarization and once per time slot using the second polarization.

15. The method according to claim 14, wherein The terminal device (300) is informed about which reference signals are transmitted in the same beam and which reference signals are transmitted in different beams.

16. The method according to claim 11 or 12, wherein: The configuration information further specifies that the terminal device (300) is configured to generate N beams for each polarization of an antenna element.

17. The method according to claim 16, wherein The number of reference signals to be received per time slot depends on N.

18. The method according to claim 16, wherein According to the reference signal reception scheme, fewer than 2N reference signals will be received per time slot.

19. The method according to claim 16, wherein According to the reference signal reception scheme, exactly N+2 reference signals will be received per time slot.

20. The method according to claim 16, wherein According to the reference signal reception scheme, two of the reference signals are separated from the remaining N reference signals by at least one OFDM symbol in the time slot, and wherein the two of the reference signals are to be received before the remaining N reference signals.

21. The method according to claim 20, wherein According to the reference signal reception scheme, two of the reference signals are placed to be received as early as possible in the time slot, and wherein the remaining N reference signals are placed to be received as late as possible in the time slot.

22. The method according to claim 20 or 21, wherein When performing the beam management procedure, a reference signal received power (RSRP) of a first reference signal received using a first polarization among the two reference signals is compared with an RSRP of a second reference signal received using a second polarization among the two reference signals, and wherein the remaining N reference signals are received using the polarization that produces the highest RSRP.

23. The method according to claim 11 or 12, wherein The terminal device (300) is equipped with an antenna array having dual-polarized antenna elements, and wherein the antenna array is connected to a baseband chain in the terminal device (300).

24. A network node (200) for performing a beam management procedure, the network node (200) comprising a processing circuit (210) configured to cause the network node (200) to: Configuration information is obtained from a terminal device (300) to which the network node (200) provides network access, wherein: The configuration information specifies that the terminal device (300) needs to evaluate different polarization states at different time units during the beam management process; as well as The beam management procedure is performed with the terminal device (300), wherein the beam management procedure involves the network node (200) transmitting a reference signal per time slot according to a reference signal transmission scheme, and wherein the reference signal transmission scheme depends on the obtained configuration information.

25. The network node (200) according to claim 24, wherein The processing circuit is further configured to cause the network node (200) to perform the method according to any one of claims 2 to 10.

26. A network node (200) for performing a beam management procedure, the network node (200) comprising: an obtaining module (210a) configured to obtain configuration information from a terminal device (300) to which the network node (200) provides network access, wherein the configuration information specifies that the terminal device (300) needs to evaluate different polarization states at different time units during the beam management process; and A beam management module (210b) is configured to perform the beam management process with the terminal device (300), wherein the beam management process involves the network node (200) transmitting a reference signal per time slot according to a reference signal transmission scheme, and wherein the reference signal transmission scheme depends on the obtained configuration information.

27. The network node (200) according to claim 26, further configured to perform the method according to any one of claims 2 to 10.

28. A terminal device (300) for performing a beam management process, the terminal device (300) comprising a processing circuit (310) configured to cause the terminal device (300) to: Providing configuration information to a network node (200), the network node (200) providing network access to the terminal device (300), wherein: The configuration information specifies that the terminal device (300) needs to evaluate different polarization states at different time units during the beam management process; as well as The beam management procedure is performed with the network node (200), wherein the beam management procedure involves the terminal device (300) receiving a reference signal from the network node (200) per time slot according to a reference signal reception scheme, and wherein the reference signal reception scheme depends on the provided configuration information.

29. The terminal device (300) according to claim 28, wherein: The processing circuit is further configured to cause the terminal device (300) to perform the method according to any one of claims 12 to 23.

30. A terminal device (300) for performing a beam management process, the terminal device (300) comprising: A providing module (310a) configured to provide configuration information to a network node (200) that provides network access to the terminal device (300), wherein the configuration information specifies that the terminal device (300) needs to evaluate different polarization states at different time units during the beam management process; and A beam management module (310b) is configured to perform the beam management process with the network node (200), wherein the beam management process involves the terminal device (300) receiving a reference signal from the network node (200) per time slot according to a reference signal reception scheme, and wherein the reference signal reception scheme depends on the provided configuration information.

31. The terminal device (300) according to claim 30, further configured to perform the method according to any one of claims 12 to 23.

32. A computer program (1220a) for performing a beam management procedure, the computer program comprising computer code which, when executed on a processing circuit (210) of a network node (200), causes the network node (200) to: Configuration information is obtained (S102) from a terminal device (300) to which the network node (200) provides network access, wherein: The configuration information specifies that the terminal device (300) needs to evaluate different polarization states at different time units during the beam management process; as well as Performing (S104) the beam management process with the terminal device (300), wherein the beam management process involves the network node (200) transmitting a reference signal per time slot according to a reference signal transmission scheme, and wherein the reference signal transmission scheme depends on the obtained configuration information.

33. A computer program (1220b) for performing a beam management process, the computer program comprising computer code which, when executed on processing circuitry (310) of a terminal device (300), causes the terminal device (300) to: Providing (S202) configuration information to a network node (200), wherein the network node (200) provides network access to the terminal device (300), wherein: The configuration information specifies that the terminal device (300) needs to evaluate different polarization states at different time units during the beam management process; as well as Performing (S204) the beam management process with the network node (200), wherein the beam management process involves the terminal device (300) receiving a reference signal from the network node (200) per time slot according to a reference signal reception scheme, and wherein the reference signal reception scheme depends on the provided configuration information.

34. A computer program product (1210a, 1210b), comprising: A computer program (1220a, 1220b) according to at least one of claims 32 and 33, and a computer-readable storage medium (1230) on which the computer program is stored.

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