Polarized reception of reference signals at a terminal device

Abstract

A mechanism for polarized reception of reference signals is provided. A method is performed by a terminal device. The terminal device is equipped with an antenna array having dual polarized antenna elements. The antenna array is connected to a baseband chain in the terminal device. The method includes receiving two reference signals sent in an OFDM symbol during a beam management process with a TRP, each reference signal coming from the same TRP port within a time slot. The two reference signals are received using a filter having a first polarization for a first of the two reference signals and a second polarization for a second of the two reference signals. The second polarization is orthogonal to the first polarization.

Description

Technical Field

[0001] The embodiments presented herein relate to methods, terminal devices, computer programs, and computer program products for polarization reception of reference signals. Background Art

[0002] In a communication network, it may be challenging to achieve 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, it may be necessary to operate in frequency bands of many different carrier frequencies. For example, it may be necessary to lower such frequency bands to achieve sufficient network coverage for wireless devices, and higher frequency bands (e.g., at millimeter wavelengths (mmW), i.e., close to and above 30 GHz) may be required to achieve the desired network capacity. Generally, at high frequencies, the propagation characteristics of wireless channels are more challenging, and beamforming may be required at both network nodes and wireless devices of the network to achieve sufficient link budgets.

[0004] At such high frequencies, narrow beam transmission and reception schemes may be required to compensate for the expected high propagation losses. For a given communication link, corresponding beams can be applied at both the network side (represented, e.g., by a network node or its transmission and reception point TRP) and the terminal (represented, e.g., by a terminal device), which are generally referred to as beam pairs for a link (BPL). It is expected that the BPL (i.e., both the beam used by the network node and the beam used by the terminal device) will be discovered and monitored by the network using measurements of downlink reference signals for beam management, such as channel state information reference signals (CSI-RS) or synchronization signal block (SSB) signals.

[0005] The beam management process can be used for the discovery and maintenance of beam pairs for a link. In some aspects, the beam management process is defined according to P-1 sub-process, P-2 sub-process, and P-3 sub-process.

[0006] CSI-RS for beam management can be sent periodically, semi-persistently, or aperiodically (event-triggered), and they can be shared among multiple terminal devices or be device-specific. SSBs are sent periodically and shared by all terminal devices. To enable a terminal device to find a suitable network node beam, during the P-1 sub-process, the network node sends reference signals in different transmit (TX) beams, and the terminal device performs measurements such as reference signal received power (RSRP) on them and reports back the N best TX beams (where N can be configured by the network). Additionally, the reference signal can be repeatedly sent on a given TX beam to allow the terminal device to evaluate a suitable receive (RX) beam. The reference signal shared among all terminal devices served by the TRP can be used to determine a first rough direction for the terminal device. Such a periodic TX beam scan at the TRP using the SSB as a reference signal can be applicable. One reason is that the SSB is anyway sent periodically (for initial access / synchronization purposes), and in addition, it is expected that the SSB will be beamformed at higher frequencies to overcome the aforementioned higher propagation losses.

[0007] Furthermore, a finer beam scan in a narrower beam can be performed at the network node during the P-2 sub-process compared to that used during the P-1 sub-process to determine a more detailed direction for each terminal device. Here, CSI-RS can be used as the reference signal. For the P-1 sub-process, the terminal device performs measurements such as reference signal received power (RSRP) and reports back the N best TX beams (where N can be configured by the network).

[0008] Additionally, the CSI-RS transmission in the transmit beam 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 corresponding beam management sub-process 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 process.

[0010] Therefore, there is still a need for an improved beam management process. Summary of the Invention

[0011] An object of embodiments herein is to provide a beam management process that takes into account the antenna architecture at the terminal device.

[0012] According to a first aspect, a method for polarimetric reception of reference signals is proposed. The method is performed by a terminal device. The terminal device is equipped with an antenna array having dual-polarized antenna elements. The antenna array is connected to a baseband chain in the terminal device. The method includes receiving, during a beam management procedure with a TRP, two reference signals transmitted in one Orthogonal Frequency Division Multiplexing (OFDM) symbol, each reference signal from the same TRP port within a time slot. The two reference signals are received using a filter having a first polarization for a first reference signal of the two reference signals and a second polarization for a second reference signal of the two reference signals. The second polarization is orthogonal to the first polarization.

[0013] According to a second aspect, a terminal device for polarimetric reception of reference signals is proposed. The terminal device is equipped with an antenna array having dual-polarized antenna elements. The antenna array is connected to a baseband chain in the terminal device. The terminal device further includes a processing circuit. The processing circuit is configured to cause the terminal device to receive, during a beam management procedure with a TRP, two reference signals transmitted in one OFDM symbol, each reference signal from the same TRP port within a time slot. The two reference signals are received using a filter having a first polarization for a first reference signal of the two reference signals and a second polarization for a second reference signal of the two reference signals. The second polarization is orthogonal to the first polarization.

[0014] According to a third aspect, a terminal device for polarimetric reception of reference signals is proposed. The terminal device is equipped with an antenna array having dual-polarized antenna elements. The antenna array is connected to a baseband chain in the terminal device. The terminal device further includes a receiving module configured to receive, during a beam management procedure with a TRP, two reference signals transmitted in one OFDM symbol, each reference signal from the same TRP port within a time slot. The two reference signals are received using a filter having a first polarization for a first reference signal of the two reference signals and a second polarization for a second reference signal of the two reference signals. The second polarization is orthogonal to the first polarization.

[0015] According to a fourth aspect, a computer program for polarimetric reception of reference signals is provided. The computer program includes computer program code which, when running on a terminal device equipped with an antenna array having dual-polarized antenna elements and connected to a baseband chain in the terminal device, causes the terminal device to perform the method according to the first aspect.

[0016] According to a fifth aspect, a computer program product is provided, which includes the computer program according to the fourth aspect and a computer-readable storage medium on which the computer program is stored. The computer-readable storage medium may be a non-transitory computer-readable storage medium.

[0017] Advantageously, these aspects enable the beam management process to take into account the antenna architecture at the terminal device.

[0018] Advantageously, these aspects improve the beam management process.

[0019] Advantageously, these aspects improve the beam management process by enabling improvements in beam selection at the terminal device.

[0020] Other objects, features, and advantages of the appended embodiments will become apparent from the following detailed disclosure, from the appended dependent claims, and from the drawings.

[0021] In general, unless otherwise clearly defined herein, all terms used in the claims shall be interpreted according to their ordinary meaning in the technical field. Unless otherwise clearly stated, all references to "an / the element, device, component, part, module, step, etc." shall be interpreted openly as referring to at least one instance of the element, device, component, part, module, step, etc. Unless clearly stated, the steps of any method disclosed herein need not be performed in the exact order disclosed. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The inventive concept will now be described by way of example with reference to the drawings, in which:

[0023] Figure 1 is a schematic diagram illustrating a communication network according to an embodiment;

[0024] Figure 2 schematically illustrates the antenna architecture of a terminal device according to an embodiment;

[0025] Figure 3 schematically illustrates a beam management process according to an embodiment;

[0026] Figure 4 is a flowchart of a method according to an embodiment;

[0027] Figure 5 schematically illustrates spatial beam patterns in different polarizations as generated by a terminal device according to an embodiment;

[0028] Figure 6 is a schematic diagram showing functional units of a terminal device according to an embodiment;

[0029] Figure 7is a schematic diagram showing functional modules of a terminal device according to an embodiment;

[0030] Figure 8 shows an example of a computer program product including a computer-readable storage medium according to an embodiment;

[0031] Figure 9 is a schematic diagram illustrating a telecommunication network connected to a host computer via an intermediate network according to some embodiments; and

[0032] Figure 10 is a schematic diagram illustrating a host computer communicating with a terminal device via a radio base station through a partial wireless connection according to some embodiments. Detailed Description

[0033] Now, the inventive concept will be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the inventive concept are shown. However, the inventive concept may 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 inventive concept to those skilled in the art. The same numbers refer to the same elements throughout the description. Any steps or features shown by dashed lines should be considered optional.

[0034] Figure 1 is a schematic diagram illustrating a communication network 100 in which the embodiments proposed herein may be applied. The communication network 100 may be a third-generation (3G) telecommunication network, a fourth-generation (4G) telecommunication network, a fifth-generation (5G) telecommunication network, or any evolution thereof, and supports any 3GPP telecommunication standard where applicable.

[0035] The communication network 100 includes a network node 140 configured to provide network access to a terminal device (represented by the terminal device 200) 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 200 is enabled to access services of the service network 130 via the network node 140 and exchange data with the service network 130.

[0036] The network node 140 includes a transmit and receive point (TRP) 150, collocated with, integrated with, or in operative communication with it. The network node 140 (via its TRP 150) and the terminal device 200 are configured to communicate with each other in a beam, one of which is illustrated by reference numeral 160. 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.

[0037] Examples of the network node 140 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 200 are a wireless device, a mobile station, a mobile phone, a cellular phone, 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.

[0038] There may be different types of antenna arrangements provided for the terminal device 200 so that the terminal device 200 can communicate effectively with the TRP 150. In this regard, an antenna panel may be defined as a rectangular antenna array of dual-polarized antenna elements, typically having one transmit / receive unit (TXRU) per polarization. An analog distribution network with phase shifters may be used to steer the directional beams generated at each such antenna panel. Alternatively, the terminal device 200 is configured for digital broadband (time-domain beamforming) beamforming that mimics the operation and function of the analog distribution network. Multiple antenna panels may be stacked adjacent to each other, and digital beamforming may be performed across the antenna panels. For the terminal device 200, depending on its physical orientation, signals may arrive and depart from all different directions. Therefore, in addition to high-gain narrow directional beams, it may be beneficial to have an antenna implementation at the terminal device 200 that enables the terminal device 200 to generate an omni-directional-like coverage for the terminal device 200. One way to increase the omni-directional coverage at the terminal device 200 is to provide the terminal device 200 with multiple antenna panels, where at least two of these antenna panels have different pointing directions.

[0039] Figure 2Schematically illustrates an example antenna architecture of a terminal device 200. According to the illustrated antenna architecture, the terminal device 200 is equipped with at least one antenna array 240a, 240b. Each antenna array 240a, 240b has dual-polarized antenna elements. In the illustrated example, each antenna array 240a, 240b has eight dual-polarized antenna elements, but as will be understood by those skilled in the art, each antenna array 240a, 240b may have fewer than eight or more than eight dual-polarized antenna elements. The antenna arrays 240a, 240b may be connected to a baseband chain 250 in the terminal device 200 (via a switch 260). In some examples, the terminal device 200 is equipped with more than one antenna array 240a, 240b. Further, two or more antenna arrays 240a, 240b may be selectively connected to the same baseband chain 250, one antenna array at a time. This enables the terminal device 200 to include only a single baseband chain 250, although it includes two or more antenna arrays 240a, 240b. In other examples, the terminal device 200 includes two or more baseband chains 250, where each baseband chain 250 may be connected to one or more antenna arrays 240a, 240b. This enables each antenna array 240a, 240b to have its own baseband chain 250. The antenna architecture may be part of a communication interface 220 of the terminal device 200.

[0040] As described above, there is still a need for improved beam management procedures. Therefore, referring to Figure 3 , Figure 3 schematically illustrates a beam management procedure consisting of three sub-procedures (referred to as P-1, P-2, and P-3 sub-procedures). These three sub-procedures will now be disclosed in more detail.

[0041] A main purpose of the P-1 subprocedure is for network node 140 to find a rough direction towards terminal device 200 by transmitting reference signals in wide but sector-narrower beams that scan across the entire corner sector. For the P-1 subprocedure, it is expected that TRP 150 uses beams with a relatively large beamwidth according to spatial beam pattern 160a. During the P-1 subprocedure, the reference signals are typically transmitted periodically and shared among all terminal devices 200 served by network node 140 in radio access network 110. According to spatial beam pattern 170a, terminal device 200 uses a wide (or even omnidirectional) beam for receiving the reference signals during the P-1 subprocedure. The reference signals can be channel state information reference signals (CSI-RS) or synchronization signal blocks (SSB) that are transmitted periodically. Furthermore, the terminal device can report N≥1 best beams and their corresponding quality values, such as reference signal received power (RSRP) values, to network node 140. The beam reporting from terminal device 200 to network node 140 can be performed rarely (to save overhead) and can be periodic, semi-persistent, or aperiodic.

[0042] A main purpose of the P-2 subprocedure is to refine the beam selection at TRP 150 by network node 140 transmitting reference signals when performing a new beam scan with narrower (compared to those used during the P-1 subprocedure) directional beams according to spatial beam pattern 160b, where the new beam scan is performed around the rough direction or beam reported during the P-1 subprocedure. During the P-2 subprocedure, according to spatial beam pattern 170b, terminal device 200 typically uses the same beams as during the P-1 subprocedure. Furthermore, terminal device 200 can report N≥1 best beams and their corresponding quality values, such as reference signal received power (RSRP) values, to network node 140. A P-2 subprocedure can be performed per terminal device 200 or per group of terminal devices 200. The reference signals can be CSI-RS transmitted aperiodically or semi-persistently. To track the movement of terminal device 200 and / or changes in the radio propagation environment, the P-2 subprocedure can be performed more frequently than the P-1 subprocedure.

[0043] A main purpose of the P-3 subprocedure is for terminal device 200 to find the best beam using analog beamforming or digital broadband (time-domain beamforming) beamforming. During the P-3 subprocedure, when terminal device 200 performs a beam scan according to spatial beam pattern 170c, reference signals are transmitted in the best reported beams of the P-2 subprocedure according to spatial beam pattern 160c. To enable terminal device 200 to compensate for blocking and / or rotation, the P-3 subprocedure can be performed at least as frequently as the P-2 subprocedure.

[0044] Due to the physical radio environment, which beam is reported as the best beam can vary for different polarizations. For example, for some non-line-of-sight (NLOS) radio propagation environments, the 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 beam at the TRP 150 between consecutive SSB transmissions. However, such a switch may cause problems with the automatic gain control (AGC) performed by the terminal device 200. One reason is that the received power of the two SSBs transmitted for two orthogonal polarizations may differ too much, e.g., by more than 10 dB.

[0045] Instead of using the P-3 subprocedure, an alternative way for the terminal device 200 to find its best beam is for the terminal device 200 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 so is that no additional CSI-RS transmission overhead is required. However, one drawback of determining the beam to be used at the terminal device 200 based on SSB transmissions is that the SSB only has one TRP port and thus is transmitted only through one polarization (per unique direction), which means the terminal device 200 may only be able to evaluate suitable beams for one polarization. But as mentioned above, if the RSRP is significantly different for different polarizations, there is a risk of selecting a non-optimal beam at the terminal device 200.

[0046] Accordingly, embodiments disclosed herein relate to a mechanism for polarization reception of reference signals. To obtain such a mechanism, there is provided a terminal device 200, a method performed by the terminal device 200, and a computer program product that includes code in the form of a computer program, for example, which when run on the terminal device 200 causes the terminal device 200 to perform the method.

[0047] Figure 4 FIG. is a flowchart illustrating an embodiment of a method for polarization reception of a reference signal. These methods are performed by the terminal device 200. These methods are advantageously provided as a computer program 820.

[0048] During a beam management procedure, the terminal device 200 receives two reference signals within the same time slot using two different polarizations. Specifically, the terminal device 200 is configured to perform step S102:

[0049] S102: During the beam management procedure between the terminal device 200 and the TRP 150, the terminal device 200 receives two reference signals transmitted in one OFDM symbol, with each reference signal coming from the same TRP port within a time slot. The two reference signals are received using a filter that has a first polarization for the first reference signal among the two reference signals and a second polarization for the second reference signal among the two reference signals. The second polarization is orthogonal to the first polarization.

[0050] The beam management procedure thus takes into account the antenna architecture at the terminal device 200.

[0051] Now, embodiments related to other details of the polarization reception of reference signals as performed by the terminal device 200 will be disclosed.

[0052] If dual-polarization beamforming is used, the polarizations will be different in different directions, so there will not be a single polarization in all directions. As long as the first polarization and the second polarization are orthogonal to each other, this is not too important.

[0053] In some aspects, the terminal device 200 may be configured to determine whether it has been rotated and by how much (if it has been rotated). The terminal device 200 may further be configured to re-evaluate the polarization state if it is determined that the terminal device 200 has been rotated. Thus, a rotation criterion may be applied by the terminal device 200 for evaluating its polarization state. Specifically, according to an embodiment, each of the first polarization and the second polarization is defined by its own polarization state, and the polarization states defining each of the first polarization and the second polarization depend on the rotational orientation of the terminal device 200. Moreover, as long as the terminal device 200 is not rotated, there may be no need to evaluate different polarization states because the polarization state may not change as long as the terminal device 200 maintains its orientation. Specifically, according to an embodiment, as long as the rotational orientation of the terminal device 200 remains unchanged, the polarization states defining each of the first polarization and the second polarization remain unchanged.

[0054] Now, some embodiments will be disclosed according to which the polarization is changed at the terminal device 200 when receiving a reference signal in order to reduce the risk of polarization mismatch. In some aspects, these embodiments can be easily combined with the above-mentioned P-1 subprocedure.

[0055] In some aspects, the terminal device 200 calculates a quality value, such as RSRP, based on the reference signals received in two OFDM symbols. That is, according to an embodiment, the terminal device 200 is configured to perform (optional) step S104:

[0056] S104: The terminal device 200 determines a common RSRP value from measurements performed by the terminal device 200 on both of these reference signals.

[0057] In this regard, a separate RSRP value can be determined first for each of the two reference signals. A common RSRP value can then be determined as the highest of these two separate RSRP values. Alternatively, a common RSRP value can then be determined as the average of these two separate RSRP values.

[0058] As disclosed above, the reference signals transmitted by the network node 140 can be of different types. In some examples, the two reference signals are received in the SSB. Additionally, in this case, the SSB can include a total of four reference signals transmitted in one OFDM symbol, each reference signal from the same TRP port within a time slot. A common RSRP value can then be determined from measurements performed by the terminal device 200 on all four of these reference signals. The RSRP of the SSB can be calculated, for example, based on the primary synchronization signal (PSS), the secondary synchronization signal (SSS), the demodulation reference signal (DMRS) frequency multiplexed with the physical broadcast channel (PBCH) signaling, or even using the control information symbol of the PBCH. This means that 3 or 4 OFDM symbols of the SSB can be used by the terminal device 200 to determine the RSRP of the SSB.

[0059] When the embodiments disclosed herein are combined with the above P-1 subprocedure, the steps of receiving the reference signals and determining the RSRP value can be repeated for each beam in the beam sweep. Thus, according to an embodiment, during the beam management procedure with the TRP 150, two other reference signals transmitted in one OFDM symbol are received, each other reference signal from the same TRP port. These two other reference signals are received using a filter having a first polarization for the first other reference signal of the two other reference signals and a second polarization for the second other reference signal of the two other reference signals. A common RSRP value is determined from measurements performed by the terminal device 200 on both of these other reference signals.

[0060] Compared with the two reference signals mentioned above, these two other reference signals can be transmitted at the TRP 150 in different beams. According to an embodiment, these two other reference signals are received in other SSBs.

[0061] The terminal device 200 can then report back to the network node 140 via the TRP 150 the SSB received with the highest RSRP value (or the highest other type of quality value). That is, according to an embodiment, the terminal device 200 is configured to perform (optional) step S106:

[0062] S106: The terminal device 200 reports to the TRP 150 the SSB among these SSBs that is received with the highest RSRP.

[0063] In some examples, all reference signals are received at the terminal device using the same beam. That is, according to the embodiment, these two reference signals are received at the terminal device 200 using the same beam.

[0064] Now, a non-limiting example of how these embodiments can be easily combined with the above P-1 sub-process will be disclosed.

[0065] Assume that the P-1 sub-process is based on the transmission of reference signals in the form of SSBs. In this case, the terminal device 200 will perform RSRP measurements on all different SSBs in the SSB burst and report the SSB indices and the corresponding RSRPs of N (1 ≤ N < 5) SSBs with the highest RSRP. Since polarization mismatch may cause an abrupt drop in the received power, the terminal device 200 switches the polarization of the beam used to receive the SSB during one SSB so that the RSRP is calculated for each of the two orthogonal polarizations in at least one OFDM symbol. In this way, the SSB beam selection reported to the TRP will be more reliable. For example, assume that there is a polarization mismatch between the TRP 150 and the terminal device 200 such that the received power becomes very poor, then the RSRP measurement may be very unreliable. Another example is that the terminal device 200 may experience a line-of-sight (LOS) condition towards the TRP 150, but due to polarization mismatch, the RSRP of the LOS beam may result in a very poor RSRP, while the RSRP of the NLOS beam (e.g., the beam reflected onto another object) reaching the terminal device 200 with a changed polarization may result in a better RSRP. This may cause the terminal device 200 to select the NLOS beam even though the LOS beam would result in a much higher RSRP in the case where there is no polarization mismatch between the TRP 150 and the terminal device 200.

[0066] Now, some embodiments will be disclosed according to which the terminal device 200 evaluates the reference signals received in different polarizations in different ways so as to select not only the best beam but also the polarization state for that beam. In some aspects, these embodiments can be easily combined with the above P-3 sub-process.

[0067] For the P-3 sub-process, when the network node 140 transmits a reference signal (in terms of CSI-RS), by using two-port CSI-RS resources, there can be two reference signals in each OFDM symbol.

[0068] The terminal device 200 can have different ways to evaluate beams for different polarizations in different manners.

[0069] In some aspects, when receiving reference signals with different polarizations, different spatial beam patterns are used. Specifically, according to an embodiment, the first reference signal among the two reference signals and the second reference signal among the two reference signals are received using different spatial beam patterns. In this regard, the first reference signal among the two reference signals can be received using a first spatial beam pattern, and the second reference signal among the two reference signals can be received using a second spatial beam pattern, where the second spatial beam pattern is different from the first spatial beam pattern. As described above, the first polarization is used when receiving the first reference signal among the two reference signals, and the second polarization is used when receiving the second reference signal among the two reference signals. Therefore, the first spatial beam pattern is used for the first polarization, and the second spatial beam pattern is used for the second polarization.

[0070] Herein, reference is made in parallel Figure 5 which illustrates at (a), (b), and (c) three examples of the spatial beam patterns 180a, 180b, 180c generated by the terminal device 200 for different polarizations P1 and P2. In Figure 5 (a) and Figure 5 (b), the spatial beam patterns for different polarizations are different from each other, but are the same in Figure 5 (c). Taking Figure 5 (a) as an example, a narrow beam is generated, where the polarization changes from beam to beam such that the polarization is orthogonal between adjacent beams. As long as there is some angular spread around the terminal device 200, even if there is a polarization mismatch between the TRP 150 and one of the polarizations of the beam in Figure 5 (a), it is very likely that the RSRP will be high enough for some of the beams in the other polarization well (depending on, for example, the density of the beams in the angular dimension). If the beams are generated from a two-fold oversampled discrete Fourier transform (DFT) grid of the beams, the drop in RSRP is quite small. It is also expected that the UE can report in the UE capability signaling how many UE beams it wants to evaluate during the beam management process, and in this case, the UE can signal a number that gives a good enough distance between the beams. Figure 5 (b)'s example can correspond to a scenario where the terminal device 200 has earlier determined a preferred polarization state, and thus most of the narrow beams are generated with this (first) polarization. However, in order to evaluate whether the previous best polarization is still preferred, the terminal device 200 generates a wider beam in the orthogonal (second) polarization. For example, if the RSRP of the wide beam is almost the same as that of the strongest narrow beam, it is very likely that the polarization of the wide beam is preferred because the beam has a lower gain. TakingFigure 5 (c) For example, the terminal device 200 generates a beam that is slightly wider compared to Figure 5 (a) and 4(b), and receives reference signals in each beam for both polarizations. In this way, the terminal device 200 can determine the preferred direction and polarization.

[0071] In some aspects, the spatial beam patterns are different from each other by having different pointing directions. That is, according to an embodiment, the first spatial beam pattern has a first pointing direction, the second spatial beam pattern has a second pointing direction, and the second pointing direction is different from the first pointing direction. Figure 5 (a) and part Figure 5 (b) are examples of this case.

[0072] In some aspects, the spatial beam patterns are different from each other by having different beam widths. That is, according to an embodiment, the first spatial beam pattern has a first beam width, the second spatial beam pattern has a second beam width, and the second beam width is different from the first beam width. Figure 5 (b) is an example of this case.

[0073] In some aspects, the spatial beam patterns are different from each other by having different numbers of beams. That is, according to an embodiment, the first spatial beam pattern is defined by a first set of beams, the second spatial beam pattern is defined by a second set of beams, and there are unequal numbers of beams in the first set of beams and the second set of beams. Figure 5 (b) is an example of this case.

[0074] Now, a non - limiting example of how these embodiments can be easily combined with the above - mentioned P - 3 sub - process will be disclosed.

[0075] During beam scanning (based on reference signals such as CSI - RS or SSB transmitted in the same beam at the TRP 150) that is part of the P - 3 process, the terminal device 200 performs beam scanning in two orthogonal polarizations. As previously mentioned, some different variants of how this beam scanning can be performed are illustrated at Figure 5 (a), (b), and (c).

[0076] Figure 6 The components of the terminal device 200 according to an embodiment are schematically illustrated according to multiple functional units. Using those capable of performing in (as Figure 8The processing circuitry 210 is provided by any combination of one or more of a suitable central processing unit (CPU), multi-processor, microcontroller, digital signal processor (DSP), etc. for software instructions stored in a computer program product 810 (e.g., in the form of a storage medium 230). The processing circuitry 210 may further be provided as at least one application specific integrated circuit (ASIC) or field programmable gate array (FPGA).

[0077] Specifically, the processing circuitry 210 is configured to cause the terminal device 200 to perform a set of operations or steps as disclosed above. For example, the storage medium 230 may store the set of operations, and the processing circuitry 210 may be configured to retrieve the set of operations from the storage medium 230 to cause the terminal device 200 to perform the set of operations. The set of operations may be provided as a set of executable instructions.

[0078] Accordingly, the processing circuitry 210 is thus arranged to perform the method as disclosed herein. The storage medium 230 may further include a permanent storage device, which may be, for example, any one or a combination of a magnetic memory, an optical memory, a solid-state memory, or even a remotely mounted memory. The terminal device 200 may further include a communication interface 220, which is at least configured for communication with the network node 140 via the TRP 150. Accordingly, the communication interface 220 may include one or more transmitters and receivers, including analog and digital components. In this regard, the communication interface 220 may include or be operatively connected to an antenna architecture as described above with reference to Figure 2 the antenna architecture described.

[0079] The processing circuitry 210 controls the general operation of the terminal device 200, for example, 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. To avoid obscuring the concepts presented herein, other components of the terminal device 200 and related functions are omitted.

[0080] Figure 7 The components of the terminal device 200 according to an embodiment are schematically illustrated in accordance with a plurality of functional modules. Figure 7 The terminal device 200 includes a receiving module 210a configured to perform step S102. Figure 7The terminal device 200 may further include a plurality of optional functional modules, such as any one of the determination module 210b configured to execute step S104 and the reporting module 210c configured to execute step S106. Generally, each of the functional modules 210a - 210c may be implemented only in hardware in one embodiment, and may be implemented by means of software in another embodiment, that is, the latter embodiment has computer program instructions stored on the storage medium 230, and when these computer program instructions run on the processing circuit, the terminal device 200 executes the corresponding steps described above in conjunction with Figure 6 The corresponding steps mentioned. It should also be noted that even though these modules correspond to parts of a computer program, they do not need to be separate modules therein, and the way they are implemented in software depends on the programming language used. Preferably, one or more or all of the functional modules 210a - 210c may be implemented by the processing circuit 210 (possibly in cooperation with the communication interface 220 and / or the storage medium 230). Thus, the processing circuit 210 may be configured to retrieve instructions provided by the functional modules 210a - 210c from the storage medium 230 and execute these instructions, thereby performing any step disclosed herein.

[0081] Figure 8 An example of a computer program product 810 including a computer - readable storage medium 830 is shown. A computer program 820 may be stored on this computer - readable storage medium 830, and the computer program 820 may cause the processing circuit 210 and entities and devices operably coupled thereto (such as the communication interface 220 and the storage medium 230) to execute the methods according to the embodiments described herein. Thus, the computer program 820 and / or the computer program product 810 may provide components for performing any step disclosed herein.

[0082] In Figure 8 the example, the computer program product 810 is illustrated as an optical disc, such as a CD (compact disc) or a DVD (digital versatile disc) or a Blu - ray disc. The computer program product 810 may 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 as a non - volatile storage medium in an external memory of the device (such as a USB (universal serial bus) memory) or a flash memory (such as a compact flash). Thus, although the computer program 820 is schematically shown as a track on the depicted optical disc, the computer program 820 may be stored in any manner suitable for the computer program product 810.

[0083] Figure 9FIG. is a schematic illustration of a telecommunications network connected to a host computer 430 via an intermediate network 420, according to some embodiments. According to an embodiment, the communication system includes a telecommunications network 410 such as a cellular network of the 3GPP type, which includes an access network 411 (such as Figure 1 the radio access network 110 in Figure 1 and a core network 414 (such as Figure 1 the core network 120 in Figure 1 ). The access network 411 includes a plurality of radio access network nodes 412a, 412b, 412c, such as NB, eNB, gNB (each corresponding to

[0084] the network node 140 of

[0085] Figure 9 Figure 1 or other types of wireless access points, and each radio access network node defines a corresponding coverage area or cell 413a, 413b, 413c. Each radio access network node 412a, 412b, 412c can be connected to the core network 414 by a wired or wireless connection 415. A first UE 491 located in the coverage area 413c is configured to be wirelessly connected to or paged by the corresponding network node 412c. A second UE 492 in the coverage area 413a can be wirelessly connected to the corresponding network node 412a. Although multiple UEs 491, 492 are illustrated in this example, the disclosed embodiments are equally applicable to cases where the only UE is in the coverage area or where the only terminal device is connected to the corresponding network node 412. The UEs 491, 492 correspond to Figure 1 the terminal device 200 of

[0084] The telecommunications network 410 itself is connected to the host computer 430, and the host computer 430 can be embodied in the hardware and / or software of a stand-alone server, a cloud-implemented server, a distributed server, or as processing resources in a server farm. The host computer 430 can be under the ownership or control of a service provider, or can be operated by or on behalf of a service provider. The connections 421 and 422 between the telecommunications network 410 and the host computer 430 can extend directly from the core network 414 to the host computer 430, or can be connected via an optional intermediate network 420. The intermediate network 420 can be one of a public, private, or managed network or a combination of more than one of them; the intermediate network 420 (if any) can be a backbone network or the Internet; specifically, the intermediate network 420 can include two or more sub-networks (not shown).

[0085] Figure 9The communication system as a whole enables a connection between the connected UEs 491, 492 and the host computer 430. This connection can be described as an over-the-top (OTT) connection 450. The host computer 430 and the connected UEs 491, 492 are configured to transmit data and / or signaling via the OTT connection 450, using the access networks 411, the core network 414, any intermediate network 420, and possibly other 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 not aware of the routing of the uplink and downlink communications. For example, the past routing of incoming downlink communications, which has data originating from the host computer 430 and destined to be forwarded (e.g., handed over) to the connected UE 491, may not be or need not be notified to the network node 412. Similarly, the network node 412 need not know the future routing of outgoing uplink communications originating from the UE 491 and destined for the host computer 430.

[0086] Figure 10 is a schematic diagram illustrating a host computer communicating with a UE via a radio access network node through a partial wireless connection. An exemplary implementation according to embodiments of the UE, radio access network node, and host computer discussed in the previous paragraphs will now be described with reference to Figure 10 In the communication system 500, the host computer 510 includes hardware 515, which includes a communication interface 516 configured to establish and maintain a wired or wireless connection with different communication devices of the communication system 500. The host computer 510 further includes a processing circuit 518, which may have storage and / or processing capabilities. Specifically, the processing circuit 518 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 host computer 510 further includes software 511, which is stored in or accessible by the host computer 510 and executable by the processing circuit 518. The software 511 includes a host application 512. The host application 512 may be operable to provide services to remote users, such as the UE 530 connected via the OTT connection 550 terminating at the UE 530 and the host computer 510. The UE 530 corresponds to Figure 1 the terminal device 200. When providing services to remote users, the host application 512 may provide user data transmitted using the OTT connection 550.

[0087] The communication system 500 further includes a radio access network node 520, which is provided in the telecommunication system and includes 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 network node 140. The hardware 525 may include a communication interface 526 for establishing and maintaining a wired or wireless connection for interfaces with different communication devices of the communication system 500, and a radio interface 527 for at least establishing and maintaining a wireless connection 570 with the UE 530 located in a coverage area (not shown in Figure 10 ) served by the radio access network node 520. The communication interface 526 may be configured to facilitate the connection 560 to the host computer 510. The connection 560 may be direct, or it may pass through a core network (not shown in Figure 10 ) in the telecommunication system and / or through one or more intermediate networks external to the telecommunication system. In the illustrated embodiment, the hardware 525 of the radio access network node 520 further includes a processing circuit 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 stored internally or accessible via an external connection.

[0088] 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 where the UE 530 is currently located. The hardware 535 of the UE 4530 further includes a processing circuit 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 UE530 further includes software 531, which is stored in or accessible by the UE 530 and executable by the processing circuit 4538. 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 a human or non-human user 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 terminating at the UE 530 and the host computer 4510. When providing services to the user, the client application 532 may receive request data from the host application 512 and, in response to the request data, provide user data. The OTT connection 550 may transmit both the request data and the user data. The client application 532 may interact with the user to generate the user data it provides.

[0089] Note that the host computer 510, radio access network node 520, and UE 530 illustrated in Figure 10 may be similar or identical to, respectively, the host computer 430, one of the network nodes 412a, 412b, 412c, and one of the UEs 491, 492 of Figure 9 . That is, the internal workings of these entities may be as shown in Figure 10 , and, independently, the surrounding network topology may be as shown in Figure 9 .

[0090] In Figure 10 , the OTT connection 550 has been abstractly drawn to illustrate communication between the host computer 510 and the UE 530 via the network node 520, without explicitly referring to any intermediate devices and the exact message routing via these devices. The network infrastructure may determine the routing, which may be configured to be hidden from the UE 530 or the service provider operating the host computer 510, or both. When the OTT connection 550 is active, the network infrastructure may further make a decision by which it dynamically changes the routing (e.g., based on load balancing considerations or reconfiguration of the network).

[0091] 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 the present disclosure. One or more of the various embodiments may improve the performance of the OTT service provided to the UE 530 using the OTT connection 550, where the wireless connection 570 constitutes the last leg. More precisely, the teachings of these embodiments may reduce interference, as the improved classification capabilities of the on-board UE generate significant interference.

[0092] For purposes of monitoring data rate, latency, and other factors that are improved in one or more embodiments, a measurement process may be provided. There may also be optional network functions for reconfiguring the OTT connection 550 between the host computer 510 and the UE 530 in response to changes in the measurement results. The measurement process and / or network functions for reconfiguring the OTT connection 550 may be implemented in the software 511 and hardware 515 of the host computer 510 or the software 531 and hardware 535 of the UE 530, or both. In an embodiment, sensors (not shown) may be deployed in or associated with communication devices through which the OTT connection 550 passes; the sensors may participate in the measurement process by providing values of the monitored quantities illustrated above, or by providing values of other physical quantities from which the software 511, 531 may calculate or estimate the monitored quantities. Reconfiguration of the OTT connection 550 may include message format, retransmission settings, preferred routing, etc.; the reconfiguration need not affect the network node 520 and may be unknown or imperceptible to the radio access network node 520. Such processes and functions may be known and practiced in the art. In some embodiments, the measurement may involve proprietary UE signaling that facilitates measurement by the host computer 510 of throughput, propagation time, latency, etc. These measurements may be implemented when the software 511 and 531 that cause messages, particularly empty messages or "dummy" messages, to be sent over the OTT connection 550 monitor propagation time, errors, etc.

[0093] The inventive concept has been mainly described above with reference to several embodiments. However, as will be readily understood by those skilled in the art, other embodiments are equally possible within the scope of the inventive concept as defined in the appended patent claims, in addition to the embodiments disclosed above.

Claims

1. A method for polarization reception of a reference signal, the method being performed by a terminal device (200), the terminal device (200) being equipped with an antenna array, the antenna array having dual-polarization antenna elements, the antenna array being connected to a baseband chain in the terminal device (200), the method include: During a beam management process with a transmission and reception point TRP (150), two reference signals transmitted in one OFDM symbol are received (S102), each reference signal coming from the same TRP port within a time slot, the two reference signals belonging to a synchronization signal block SSB consisting of four OFDM symbols, the SSB being transmitted with one polarization, wherein the two reference signals are received using a filter, the filter having a first polarization for a first reference signal of the two reference signals and a second polarization for a second reference signal of the two reference signals, and wherein the second polarization is orthogonal to the first polarization.

2. The method according to claim 1, further comprising: include: A common reference signal received power, RSRP, value is determined (S104) from measurements performed by the terminal device (200) on both reference signals.

3. The method according to claim 1, in, The SSB includes a total of four reference signals sent in one OFDM symbol, each reference signal coming from the same TRP port within the time slot.

4. The method according to claim 3, in, The one common RSRP value is determined from measurements performed by the terminal device (200) on all four reference signals.

5. The method according to any one of claims 1, 3 and 4, in, During the beam management procedure with the TRP (150), two other reference signals transmitted in one OFDM symbol are received, each other reference signal coming from the same TRP port, wherein the two other reference signals are received using the filter having a first polarization for a first of the two other reference signals and a second polarization for a second of the two other reference signals, and wherein a common RSRP value is determined from measurements performed by the terminal device (200) on both of the two other reference signals.

6. The method according to claim 2, in, During the beam management procedure with the TRP (150), two other reference signals transmitted in one OFDM symbol are received, each other reference signal coming from the same TRP port, wherein the two other reference signals are received using the filter having a first polarization for a first of the two other reference signals and a second polarization for a second of the two other reference signals, and wherein a common RSRP value is determined from measurements performed by the terminal device (200) on both of the two other reference signals.

7. The method according to claim 5, in, Receive the two other reference signals in other Synchronization Signal Blocks (SSBs).

8. The method according to claim 6, wherein, Receive the two other reference signals in other Synchronization Signal Blocks (SSBs).

9. The method according to claim 8, further comprising: Report (S106) the SSB with the highest RSRP received in the SSBs to the TRP (150).

10. The method according to any one of claims 1 to 4, wherein, Receive the two reference signals at the terminal device (200) using the same beam.

11. The method according to claim 1, wherein, Receive the first reference signal of the two reference signals and the second reference signal of the two reference signals using spatially different beam patterns.

12. The method according to claim 11, wherein, Receive the first reference signal of the two reference signals using a first spatial beam pattern, receive the second reference signal of the two reference signals using a second spatial beam pattern, and wherein the second spatial beam pattern is different from the first spatial beam pattern.

13. The method according to claim 12, wherein, The first spatial beam pattern has a first pointing direction, the second spatial beam pattern has a second pointing direction, and wherein the second pointing direction is different from the first pointing direction.

14. The method according to claim 12, wherein, The first spatial beam pattern has a first beam width, the second spatial beam pattern has a second beam width, and wherein the second beam width is different from the first beam width.

15. The method according to claim 12, wherein, The first spatial beam pattern is defined by a first set of beams, the second spatial beam pattern is defined by a second set of beams, and wherein there is an unequal number of beams in the first set of beams and the second set of beams.

16. The method according to any one of claims 1 to 4, wherein, Each of the first polarization and the second polarization is defined by its own polarization state, and wherein the polarization states defining each of the first polarization and the second polarization depend on the rotational orientation of the terminal device (200).

17. The method according to claim 16, wherein, As long as the rotational orientation of the terminal device (200) remains unchanged, the polarization states defining each of the first polarization and the second polarization remain unchanged.

18. A terminal device (200) for polarization reception of reference signals, the terminal device (200) being equipped with an antenna array having dual-polarized antenna elements, the antenna array being connected to a baseband chain in the terminal device (200), the terminal device (200) further comprising processing circuitry (210) configured to cause the terminal device (200) to: During the beam management process with the transmit and receive point TRP (150), two reference signals transmitted in one OFDM symbol are received, each reference signal from the same TRP port within a time slot, and the two reference signals belong to a synchronization signal block SSB consisting of four OFDM symbols, and the SSB is transmitted through one polarization. Wherein, The two reference signals are received using a filter that has a first polarization for a first reference signal of the two reference signals and a second polarization for a second reference signal of the two reference signals, and wherein the second polarization is orthogonal to the first polarization.

19. The terminal device (200) according to claim 18, Wherein, The processing circuit is further configured to cause the terminal device (200) to perform the method according to any one of claims 2 to 17.

20. A terminal device (200) for polarized reception of reference signals, the terminal device (200) being equipped with an antenna array having dual-polarized antenna elements, the antenna array being connected to the baseband chain in the terminal device (200), and the terminal device (200) further comprises: A receiving module (210a) configured to, during the beam management process with the transmit and receive point TRP (150), receive two reference signals transmitted in one OFDM symbol, each reference signal from the same TRP port within a time slot, and the two reference signals belong to a synchronization signal block SSB consisting of four OFDM symbols, and the SSB is transmitted through one polarization, wherein the two reference signals are received using a filter that has a first polarization for a first reference signal of the two reference signals and a second polarization for a second reference signal of the two reference signals, and wherein the second polarization is orthogonal to the first polarization.

21. The terminal device (200) according to claim 20, further configured to perform the method according to any one of claims 2 to 17.

22. A computer-readable storage medium (830) having stored thereon computer code that, when run on the processing circuit (210) of a terminal device (200), the terminal device (200) being equipped with an antenna array having dual-polarized antenna elements, the antenna array being connected to the baseband chain in the terminal device (200), causes the terminal device (200) to: During the beam management process with the transmit and receive point TRP (150), receive (S102) two reference signals transmitted in one OFDM symbol, each reference signal from the same TRP port within a time slot, and the two reference signals belong to a synchronization signal block SSB consisting of four OFDM symbols, and the SSB is transmitted through one polarization. Wherein, A filter is used to receive the two reference signals, the filter having a first polarization for a first reference signal of the two reference signals and a second polarization for a second reference signal of the two reference signals, and wherein the second polarization is orthogonal to the first polarization.

23. A computer program product (810) comprising a computer program (820) which, when run on a processing circuit (210) of a terminal device (200), the terminal device (200) being equipped with an antenna array having dual polarization antenna elements, the antenna array being connected to a baseband chain in the terminal device (200) causes the terminal device (200) to perform the method according to any one of claims 1 to 17.

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