SYP349050WO01 1 E39500WO SN D E S C R I P T I O N MULTI-DEVICE TRANSMISSION AT COVERAGE ENHANCING DEVICE USING MULTI- PLE POLARIZATIONS TECHNICAL FIELD Various examples of the disclosure generally pertain to communication, via a coverage en- hancing device, between a transmitter communication device and multiple receiver communi- cation devices, as well as communication, via a coverage enhancing device, between multi- ple transmitter communication devices and a receiver communication device. BACKGROUND To increase a coverage area for wireless communication, it is envisioned to use coverage enhancing devices (CEDs), such as Network Controlled Repeaters (NCRs) or re-configura- ble relaying devices (RRD). CEDs can also be referred to as network enhancement devices, since they generally enhance coverage, rank, and/or localizations. One example of RRDs are re-configurable reflective devices, sometimes also referred to as reflecting large intelli- gent surfaces (LISs). See, e.g., Huang, C., Zappone, A., Alexandropoulos, G. C., Debbah, M., & Yuen, C. (2019). Reconfigurable intelligent surfaces for energy efficiency in wireless communication. IEEE Transactions on Wireless Communications, 18(8), 4157-4170. An RRD can be implemented by an array of antennas that can reflect incident electromag- netic waves/signals. The array of antennas can be semi-passive. Semi-passive can corre- spond to a scenario in which the antennas can impose a variable phase shift and typically provide no signal amplification. In contrast, NCRs can amplify a signal for each antenna element of a respective array. An NCR can implement one of reflection for coverage enhancement, amplify-forward for cover- age enhancement, or decode-forward for coverage enhancement. Each antenna element may impose an antenna-element-specific amplitude gain and phase shift (i.e., provide signal amplification and variable phase shift). Oftentimes, operation of an NCR may be restricted to analog domain; i.e., digital forward error correction may not be provided. An NCR may in- clude multiple antenna arrays, e.g., one for receiving and one for transmitting. There may be signal processing in the baseband in between receiving and transmitting. For a CED, an input spatial direction (or simply, input direction) from which incident signals on a radio link are accepted by a CED and an output spatial direction (or simply, output direc- tion) into which the incident signals are redirected by the CED can be re-configured by changing a phase relationship (and, where possible, amplitude relationship) between the an- tennas. This corresponds to configuring a spatial filter at the CED. An access node (AN) may transmit signals to a wireless communication device (UE); some- times also referred to as terminal) via a CED. The CED may accept or receive the incident signals from an input spatial direction and forward or transmit the incident signals in an out- put spatial direction to the UE. The AN may transmit the signals using a beam directed to the CED. Scenarios are possible where multiple UEs are served by the AN via a CED. See WO 2021 109345 A1. SYP349050WO01 2 E39500WO SN SUMMARY There is a need for advanced techniques of communicating via a CED. Specifically, there is a need for techniques which facilitate communicating contemporaneously with multiple com- munication devices via a CED. This need is met by the features of the independent claims. The features of the dependent claims define embodiments. Various techniques disclosed herein facilitate communicating between a first communication device (CD) and multiple second CDs via a CED. This can be referred to as multi-device transmission (MDT). Different data streams can be provided by the first CD to the multiple second CD. For instance, multiple UEs can be served by an AN via a CED. Uplink and/or downlink transmission of data is possible using MDT. According to various examples, multiple data streams are transmitted by the AN using two polarizations of the transmitted signals and then forwarded at the CED. Precoding at the AN takes the overall channel towards the UEs into account, this channel also being dependent on the spatial filter applied at the CED. The spatial filter at the AN can be determined jointly with the precoder at the AN, to facilitate efficient precoding. This allows forwarding of one data stream to a first UE and forwarding of a second data stream to a second UE, e.g., with low or no interference at the UEs. Various techniques pertain to scheduling strategies at the AN. According to examples, scheduling is based on polarization indications of the UEs. The UEs can indicate how their receiver operates with respect to polarization of incident signals. Different receiver types can be co-scheduled. According to examples, a method of operating an AN is disclosed. The AN is associated with a communications network, e.g., a cellular network (in which case the AN would be referred to as base station, BS). The AN communicates wirelessly with a plurality of UEs via a CED. The method includes requesting, from each UE of the plurality of UEs, a respective polariza- tion indication. The polarization indication is indicative of whether the respective UE includes a first rank-1 receiver or transmitter type or a second rank-1 receiver or transmitter type. Rank-1 indicates that the UE can only receive or transmit a single data stream at a time. The first rank-1 receiver or transmitter type is configured to receive or transmit a linear polari- zation. The second rank-1 receiver or transmitter type is configured to receive or transmit a circular polarization. It is to be understood that the features mentioned above and those yet to be explained below may be used not only in the respective combinations indicated, but also in other combina- tions or in isolation without departing from the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG.1 schematically illustrates a rank-1 linear polarized receiver according to various exam- ples. FIG.2 schematically illustrates a rank-1 circular polarized receiver according to various ex- amples. SYP349050WO01 3 E39500WO SN FIG.3 schematically illustrates the probability of a certain power required for zero-forcing precoding at the BS for random realizations of relative orientations of UEs with respect to a CED according to various examples, wherein in FIG.3 pairs of UEs are co-scheduled that both have rank-1 linear polarized receiver types. FIG.4 schematically illustrates the probability of a certain power required for zero-forcing precoding at the BS for random realizations of relative orientations of UEs with respect to a CED according to various examples, wherein in FIG.4 pairs of UEs are co-scheduled which include one UE having rank-1 linear polarized receiver type and another UE having rank-1 circular polarized receiver type, respectively. FIG.5 illustrates a communication system including a BS and a UE according to various ex- amples. FIG.6 schematically illustrates further details with respect to the BS and the UE according to various examples. FIG.7 schematically illustrates communication between multiple UEs in the BS via a CED. FIG.8 schematically illustrates details with respect to a CED. FIG.9 is a flowchart of a method according to various examples. FIG.10 is a signaling diagram according to various examples. FIG.11 is a signaling diagram according to various examples. DETAILED DESCRIPTION Some examples of the present disclosure generally provide for a plurality of circuits or other electrical devices. All references to the circuits and other electrical devices and the function- ality provided by each are not intended to be limited to encompassing only what is illustrated and described herein. While particular labels may be assigned to the various circuits or other electrical devices disclosed, such labels are not intended to limit the scope of operation for the circuits and the other electrical devices. Such circuits and other electrical devices may be combined with each other and/or separated in any manner based on the particular type of electrical implementation that is desired. It is recognized that any circuit or other electrical de- vice disclosed herein may include any number of microcontrollers, a graphics processor unit (GPU), integrated circuits, memory devices (e.g., FLASH, random access memory (RAM), read only memory (ROM), electrically programmable read only memory (EPROM), electri- cally erasable programmable read only memory (EEPROM), or other suitable variants thereof), and software which co-act with one another to perform operation(s) disclosed herein. In addition, any one or more of the electrical devices may be configured to execute a program code that is embodied in a non-transitory computer readable medium programmed to perform any number of the functions as disclosed. In the following, examples of the disclosure will be described in detail with reference to the accompanying drawings. It is to be understood that the following description of examples is not to be taken in a limiting sense. The scope of the disclosure is not intended to be limited by the examples described hereinafter or by the drawings, which are taken to be illustrative only. The drawings are to be regarded as being schematic representations and elements illus- trated in the drawings are not necessarily shown to scale. Rather, the various elements are SYP349050WO01 4 E39500WO SN represented such that their function and general purpose become apparent to a person skilled in the art. Any connection or coupling between functional blocks, devices, compo- nents, or other physical or functional units shown in the drawings or described herein may also be implemented by an indirect connection or coupling. A coupling between components may also be established over a wireless connection. Functional blocks may be implemented in hardware, firmware, software, or a combination thereof. Techniques are described that facilitate wireless communication between CDs. A wireless communication system includes one or more transmitter CDs and one or more receiver CDs. In some examples, the wireless communication system can be implemented by nodes of a wireless communication network, e.g., a radio-access network (RAN) of a 3GPP-specified cellular network (NW). In such a case, a Transmitter (TX) CD or a Receiver (RX) CD can be implemented by a BS of the RAN. According to various examples, a BS provides DL transmission to multiple UEs. In other ex- amples, multiple UEs provide UL transmissions to a given BS. For the sake of simplicity, various examples will be primarily disclosed in the context of a DL transmission from a BS of a cellular NW to multiple UEs. However, such techniques are equally applicable to UL transmission from multiple UEs to a BS. According to the disclosure, the wireless communication system may, in some scenarios, in- clude a CED. The CED supports, e.g., UL and/or DL transmission or SL transmission. According to various examples, MDT is employed. This means that the BS contemporane- ously transmits two data streams to two UEs and the CED forwards one data stream to a first UE and another data stream to a second UE. For UL, each UE transmits a data stream and the data stream is multiplexed at the CED and then de-multiplexed at the BS. According to examples, this de-multiplexing at the CED or at the BS is implemented using multiple polarizations, e.g., two orthogonal linear polarizations (H-POL and V-POL) or two or- thogonal circular polarization (LHCP and RHCP). Examples will be primarily disclosed in the context of an implementation of the CED by an RRD that is capable to adjust the phase of incident signals individually for each one of the multiple polarizations, but is not capable of adjusting the amplitude. However, the techniques disclosed herein could be also applied to an implementation of the CED by an NCR that can adjust, individually for both polarizations, the phase and amplitude of incident signals. In the disclosure, MDT for UEs that have a rank-1 receiver or transmitter type is considered. These UEs may be referred to as single-polarized UEs. While dually polarized UEs is the dominant case, single polarized UEs can find applications in low-cost-device type of sys- tems, e.g., Internet of Things (IoT), sensors, etc. Such single-polarized UEs have a compara- tively simple radio frequency (RF) hardware configuration. A single polarized UE includes a receiver (or a transmitter) that has a single baseband pro- cessing RF circuitry. For instance, a rank-1 receiver type has a single analog-to-digital con- verter; and a rank-1 transmitter type has a single digital-to-analog converter. A rank-2 re- ceiver type would include two RF processing chains to separately process two data streams. For illustration, FIG.1 illustrates a rank-1 receiver 551 of a first type that is configured to re- ceive a linear polarization (hereinafter, rank-1 linear polarized receiver type). For this, the SYP349050WO01 5 E39500WO SN rank-1 receiver 551 includes an antenna element 501 that is sensitive to a given polarization direction, e.g., either H-POL or V-POL. In a conventional manner, the rank-1 linear polarized receiver 551 includes RF processing circuitry such as a filter 511, an amplifier 512, a mixing stage 513 to mix with an intermediate frequency 514 and finally an ADC 515. FIG.2 illustrates a rank-1 receiver 552 of a second type that is configured to receive a circu- lar polarization (hereinafter, rank-1 circular polarized receiver type). For this, the rank-1 re- ceiver 552 includes two antenna elements 501, 502 that are sensitive to orthogonal polariza- tions (H-POL and V-POL, arbitrarily defined). There is a 90-degree phase shifter 505 provi- sioned before combining the two signals (this can be referred to as a “linear combiner”). This makes the receiver 552 sensitive to circular polarization, e.g., LHCP or RHCP, depending on the direction of the phase shift. Thus, a linear combination of a dually polarized field is ob- served by the receiver 552. The individual polarization components H-POL and V-POL are not resolved. Such receivers 551, 552 as illustrated in FIG.1 and FIG.2 are only capable of receiving a single data stream at a time, because there is only a single RF processing chain; accord- ingly, they are called rank-1 receivers. In examples, a large number of such single polarized UEs is served by a BS via a CED. Via the CED, the BS can serve two of these single polarized UEs simultaneously since the BS has two polarizations. Thus, pairs of UEs to be simultaneously served using polarization MDT are selected. According to examples, pairs of UEs are co-scheduled to shared blocks of time-frequency resources on an UL or DL shared channel. Techniques are disclosed hereinafter to determine suitable CED spatial filters to serve pairs of UEs using polarization MDT. Techniques are disclosed that enable the CED to de-multi- plex two incoming data streams from the BS on shared time-frequency resources (and same spatial resource), for DL transmission. For UL transmission, the CED can multiplex two in- coming data streams, one from each UE. Investigating the ensuing throughputs reveals that the type of UE receiver or transmitter (for example rank-1 circular polarized type or rank-1 lin- ear polarized type as discussed above) significantly impacts the achievable rates. There are three options for co-scheduling pairs of UEs to employ the polarization MDT. These options are summarized below in TAB.1. TAB.1: Three options for co-scheduling pairs of UEs to shared time-frequency resources employing a polarization-based MDT via a CED. SYP349050WO01 6 E39500WO SN Various techniques are based on the finding that co-scheduling pairs of UEs in option III of TAB.1 can increase data throughput and/or reduce required transmit power when compared to options I and II in TAB.1. Such pairing of rank-1 linear polarized UE and rank-1 circular polarized UE gains, on aver- age, at least 0.7dB signal-to-noise ratio (SNR) over a pairing involving two rank-1 circular UEs, cf. option I of TAB.1. In order to harvest this gain, the BS must be aware of the polarization type per UE. There- fore, signaling from the UEs to the BS is employed, said signaling being indicative of their po- larizations. According to examples, the BS can request from the served UEs a polarization indication that is indicative of whether the respective UE is a rank-1 linear polarized UE or a rank-1 circular polarized UE (i.e., has a rank-1 linear polarized receiver or transmitter type or has a rank-1 circular polarized receiver or transmitter type). This request can be triggered by a scheduling procedure. These findings of option III being superior to options I and II of TAB.1 are motivated by a system model analysis below. The system model analysis is for DL transmission from a BS to two UEs (UE-1, UE-2) via a CED. Dually polarized BS and a dually polarized CED are assumed. This means that the BS can transmit and receive individually for two different polarizations, e.g., H-POL and V-POL or LHCP and RHCP. The CED has two separate antenna arrays, i.e., for H-POL and V-POL or LHCP and RHCP (the coordinate system of CED is rotated with respect to the coordinate system of the BS). It is assumed that three beam directions (i) BS to CED, (ii) CED to UE-1, and (iii) CED to UE- 2 are all known. These could be determined using positioning techniques such as triangula- tion, angle of departure, angle of arrival, etc. It is alternatively or additionally possible to use a beam-sweep procedure. The CED then performs a beam split per polarization, i.e., polarization-based MDT is em- ployed. The polarization precoder (i.e., antenna weights – amplitude and phase – for both polariza- tions) at the BS can be selected freely. Each UE (UE-1, UE-2) is rotated with respect to the coordinate system of the CED. Each UE (UE-1, UE-2) has as rank-1 receiver type, e.g., rank-1 circular polarized receiver type or rank-1 linear polarized receiver type. The path losses between the CED and the two UEs (UE-1, UE-2) are identical and are omit- ted from the system model. With that the received signals at the two UEs read where “∘” denotes Hadamard product (i.e., elementwise matrix multiplication), ^ _^ is the signal arriving at the CED horizontally polarized antennas within the receive part of the CED beam, ^ _^ is the signal arriving at the CED’s vertically polarized antennas within the receive part of SYP349050WO01 7 E39500WO SN the CED beam, ^ _^^ is the fraction of the signal ^ _^ reflected to UE ^, ^ _^^ is the fraction of the signal ^ _^ reflected to UE ^, ^ _^^ is the fraction observed at UE ^ of the signal reflected from the horizontally polarized CED antennas, ^ _^^ is the fraction observed at UE ^ of the signal reflected from the vertically polarized CED antennas. ^ ∈ {1,2} for UE-1 and UE-2, respec- tively. ^ _^/^^ thus denote beam-splitting ratios for the RRD for the two channels between the BS and UE-1 and the BS and UE-2, respectively. ^ _^^ , ^ _^^ thus denotes the channels for the two polarizations between the CED and the re- spective UE (^ = 1 or ^ = 2 for UE-1 and UE-2, respectively). The vector ^{[^} ^^ ^{^} ^^ ^] can be characterized as follows. Let ^(^ _^ ) be the rotation matrix rep- resenting the coordinate transformation between the CED and UE ^ (this depends on the rel- ative orientation between each UE and the CED, respectively). Further, let ^ _^ be the linear combiner by which UE ^ observes that horizontal and vertical parts of the arriving signal. Then, [ ^{^} _^^ ^{^} _^^ ^] _{= ^^^} ⁽ _^^ ⁾ _. (2) According to examples, UEs provide a polarization indication that is indicative of ^ _^ . In fact, it is only necessary to indicate the relative phase between the two entries. An ^-array CED (i.e., having ^ antenna elements) naturally introduces an array gain of ^ ^{^} ; however, as neither path-losses nor noise are incorporated into the system model, the array gain can be ignored. With that, it follows that there are restrictions / constraints on the elements ^, (stated for the ^ _^ variables, but can be verbatimly repeated for ^ _^ ), as outlined in TAB.2. These con- straints are derived for the asymptotic regime ^ → ∞, and hold true, with probability one, for CED-UE directions independently and randomly drawn from the set of all directions accord- ing to continuous probability distributions. SYP349050WO01 8 E39500WO SN TAB.2: constraints for the CED to implement beam-splitting ratios. These constraints are rooted in the physical operational limitations of the CED, e.g., power conservation, etc. On the other hand, the phases of both ^ _^^ and ^ _^^ can be freely, and independently, chosen. In Eq. (1), the channel between the BS and the RRD is omitted. This is considered next. Let ^ _^ and ^ _^ denote the data symbols intended for UE-1 and UE-2, respectively (these define the data stream). Then Eq. (1) can be rewritten as where ^ is a 2 × 2 matrix representing the precoder operations at the BS, and ^ ⁽ ^ _^ ⁾ repre- sents a coordinate transformation between the BS and the RRD. P can mix the data streams associated with the two individual UEs. It is possible to further decompose ^ as ^ = ^ ^{^^(} ^ _^ ⁾ ^ _^ , which gives To analyze the performance of this model, it suffices to study the channel dependent part, that is, the properties of the matrix are studied: ^ ^ ^ ^^ _^^ ^ _^^ ^ _{^^ ^^} ^ _^^ ^ _^^ ∘ ^ ^ _^^ ^ _^^ ^^. (5) Assuming zero-forcing precoding applied at the BS, it follows that the beam-splitting ratios at the CED (^-variables) are to be optimized as the solution to In other words: this is the minimum power necessary at the BS to invert the channel. The ar- guments solving Equation 6 represent the CED configuration that minimizes the necessary transmit power at the BS to create interference free reception at the two UEs and equal re- ceive power at the two UEs. Equation 6 poses an optimization problem that can be solved using a numerical optimization that varies the beam-splitting ratios. It also yields the transmit precoders at the BS, because the channel is inverted according to zero-forcing precoder. The numerical optimization in- cludes the constraints according to TAB.2. SYP349050WO01 9 E39500WO SN The optimization problem according to the goal function of Equation 6 is only one example. This example rewards a low transmit power at the BS. Other goal functions are conceivable, e.g., rewarding overall data throughput between the BS and the UEs (UE-1, UE-2). The optimization problem of Equation 6 has no closed form solution, and a numerical optimi- zation is thus used. This numerical optimization is sensitive to the starting position. In all sim- ulations to be presented, a single randomly chosen starting position is used. By using more advanced optimizations, all simulated results can be improved upon. When discussing the various gains below, the reported gains are the minimum gains that are possible; hence, the wording “at least 0.7dB gain” used above. There are two options for selecting the vectors ^ _^ that could be claimed to be standard choices for UE implementations, namely, circular and linear polarization (cf. TAB.1). This corresponds to rank-1 circular UEs and rank-1 linear UEs. The BS has different options to co-schedule UEs based on their polarization indications that are indicative of ^ _^ , considering that some are rank-1 circular UEs and some are rank-1 lin- ear UEs, cf. TAB.1. The performance of these options is discussed next. CO-SCHEDULING TWO RANK-1 CIRCULAR POLARIZED UEs (TAB.1: OPTION I) A scenario is considered in which two rank-1 circular UEs are co-scheduled. With rank-1 cir- cular UEs, ^ _^ ∈ { ^[ 1 ^ ^] , ^[ 1 − ^ ^] }, ^ = 1,2. This can be achieved by the phase shifter 505 in FIG. 2. Note that it is not precluded that ^ _^ = ^ _^ , and further, the vectors have not been normal- ized. The two vectors { ^[ 1 ^ ^] , ^[ 1 − ^ ^] } are eigenvectors of rotation matrices, which implies that [ ^{^} _^^ ^{^} _^^ ] = e ^{^^^} ^ _^ (7) for some value ^ _^ (which depends on ^ _^ and which of the two vectors that was chosen as ^ _^ ). However, as the terms e ^{^^^} can be absorbed into the ^-variables, it is possible to ignore the presence of e ^{^^^} for performance analysis. Without loss of generality, assume that ^ _^ = [1 ^]. Then, Equation 3 can be rewritten as: It is not hard to see that it is optimal (for an optimization considering zero-forcing precoders optimizing the transmit power, cf. Equation 6) to select the ^-variables as, e.g., ^| ^ _^^ ^| = ^| ^ _^^ ^| = 1, which implies that ^| ^ _^^ ^| = ^| ^ _^^ ^| = 0. In other words, this means that there is no beam splitting performed at the RRD. The horizontally polarized RRD antennas serve UE-1 and the vertical antennas serve UE-2. Altogether, this gives ^ ^ _^ ^ = ^1 0 ^ _^ ^ _^ ^ ^ ^ 0 1 ^ _^ (9) achieved with the BS precoder ^ _^ = ^, which corresponds to a power to invert the channel |^ _^ | ^{^} = 2. The data streams of the two UEs are not mixed. I.e., transmit signal components at SYP349050WO01 10 E39500WO SN the BS for H-POL only include signals for UE-1 and transmit signal components at the BS for V-POL only include signals for UE-2. Such a scenario may be beneficial where a certain power budget needs to be met. The be- havior is fully deterministic. CO-SCHEDULING TWO RANK-1 LINEAR POLARIZED UEs (TAB.1: OPTION II) The linear polarization is defined as any real-valued vectors ^ _^ . As the rotation matrices are assumed random, one may select = ^ _^ = [√20] (cf. FIG.1 where only H-POL or V-POL is received); the radical is to normalize the energy to the same as is used in circular polariza- tion. With that: In this case (different to Equation 8) optimization of the ^-variables (beam-splitting ratios)) is not straightforward, but can be done via numerical optimization. Furthermore, the perfor- mance now depends on the particular angles ^ _^ . In FIG.3, the resulting power ^| ^ _^ ^{|^} , neces- sary to invert the channel for zero-forcing precoding, is illustrated. This is calculated for the ^-variables leading to the minimum such power. In detail, FIG.3 illustrates the frequency of occurrence of the respective power ^| ^ _^ ^{|^} assuming different angles ^ _^ (3000 random realiza- tions). In FIG.3, the vertical dashed lines refers to the power required to invert the channel ( ^| ^ _^ ^{|^} ) for the case of co-scheduling two rank-1 circular UEs (cf. TAB.1: option I; Equation 9). As illustrated in FIG.3, in about 65% of the cases, co-scheduling two rank-1 linear UEs is su- perior to co-scheduling two rank-1 circular polarized UEs (the mass to the left of the dashed line). Not shown in FIG.3 is that some realizations of the angles ^ _^ result in super-large power when co-scheduling two rank-1 linear UEs. The maximum in the 3000 realizations of the angles ^ _^ was a power of about ^| ^ _^ ^{|^} = 700. The implication is that the blue curve actu- ally extends far, far, to the right in the plot of FIG.3 (arrow in FIG.3). Accordingly, the aver- age power required to invert the channel when co-scheduling to rank-1 linear UEs is, in fact, about 4. This is more than for co-scheduling to rank-1 circular UEs. Summarizing these findings of FIG.3, in a communication system including two rank-1 polar- ized UEs and a dually polarized RRD capable of performing beam splitting, the beam split- ting pattern (spatial filter, beam splitting ratios) at the RRD should be optimally configured. If the BS can do arbitrary precoding, the optimal RRD configuration depends on (i) the rota- tions between UEs and the RRD, and (ii) the polarization profile at the UEs. As illustrated above, the performance of co-scheduling two rank-1 circular polarized UEs is deterministic and there is no beam split at the RRD. Further, the rotations between the UEs and the RRD do not matter. There are scenarios possible where this is conceivable, e.g., for highly mobile UEs. On the other hand, when co-scheduling two rank-1 linear polarized UEs, there is active beam split at the RRD, the rotations between the UEs and the RRD matter (cf. FIG.3), and in most cases the performance improves. But in some cases, the performance is extremely SYP349050WO01 11 E39500WO SN bad with linear polarization. This oftentimes prevents TAB.1: option II being the preferred choice over TAB.1: option I. CO-SCHEDULING RANK-1 LINEAR UE WITH RANK-1 CIRCULAR UE (TAB.1: OPTION III) When a rank-1 linear polarized UE is co-scheduled with a rank-1 circular polarized UE, this gives = [1 ^] and ^ _^ = [√20]. Employing the optimization of Equation 6, a performance ac- cording to FIG.4 is obtained (FIG.4 also corresponds to the optimization results of 3000 ran- dom realizations of angles ^ _^ ). From a comparison of FIG.3 with FIG.4, it follows that the performance of TAB.1: option III is considerably better than TAB.1: option II, as the curve is well concentrated to the left of the red line. In fact, in 88% of the cases the required power is less than 2. The maximum power observed is 3.2 (i.e., there are no extremely high powers necessary as in FIG.3). The mean power is 1.7. FIG.5 schematically illustrates a communication system 100. The communication system 100 includes two CDs 101, 102 that are configured to communicate with each other via a ra- dio link 112. In the example of FIG.5, the CD 101 is implemented by a BS 101 of a cellular NW and the CD 102 is implemented by a UE 102. The UE 102 could be, e.g., a smartwatch, a smart TV, a smart meter, to give just a few ex- amples. The UE 102 is a rank-1 linear or circular polarized UE, cf. FIG.1 or FIG.2. As a general rule, the techniques described herein could be used for various types of com- munication systems, e.g., also for peer-to-peer communication, etc. For the sake of simplic- ity, however, hereinafter, various techniques will be described in the context of a communica- tion system that is implemented by an BS 101 of a cellular NW and a UE 102. As illustrated in FIG.5, there can be DL communication, as well as UL communication. Ex- amples described herein particularly focus on the DL communication, but similar techniques may be applied to UL communication and/or sidelink communication. While in the scenario of FIG.5 only a single UE is shown, as a general rule, multiple UEs can be present in a respective communication system 100 and MDT transmission is possible, be- tween the BS 101 and the multiple UEs. FIG.6 illustrates details with respect to the BS 101. The BS 101 implements an access node of a communications network, e.g., a 3GPP-specified cellular network. The BS 101 includes control circuitry that is implemented by a processor 1011 and a non-volatile memory 1015. The processor 1011 can load program code that is stored in the memory 1015. The proces- sor 1011 can then execute the program code. Executing the program code causes the pro- cessor to perform techniques as described herein, e.g.: transmitting and/or receiving (com- municating) payload data on the data link 112 on the data carrier 111, e.g., via a CED (not shown in FIG.6); performing an optimization to determine precoders based on zero-forcing a channel; obtaining an indication of a receiver or transmitter type from the UE 102; etc. FIG.6 also illustrates details with respect to the UE 102. The UE 102 includes control cir- cuitry that is implemented by a processor 1021 and a non-volatile memory 1025. The proces- SYP349050WO01 12 E39500WO SN sor 1021 can load program code that is stored in the memory 1025. The processor can exe- cute the program code. Executing the program code causes the processor to perform tech- niques as described herein, e.g.: transmitting and/or receiving (communicating) payload data on the data link 112 (cf. FIG.1) on the data carrier 111, e.g., via an CED (not shown in FIG. 6); providing an indication of a receiver or transmitter type to the cellular NW, etc. FIG.6 also illustrates details with respect to communication between the BS 101 and the UE 102 on the data carrier 111. The BS 101 includes an interface 1012 that can access and con- trol multiple antennas 1014. Likewise, the UE 102 includes an interface 1022 that can access and control an antenna 1024. For instance, the interface 1022 could be implemented as de- scribed in connection with FIG.1 or FIG.2. The interface 1012 can each include one or more TX chains and one or more RX chains (the UE 102 may include only a single TX chain and/or only a single RX chain). For instance, such RX chains can include low noise amplifiers, analogue to digital converters, mixers, etc. Analog and/or digital beamforming would be possible. Thereby, phase-coherent transmitting and/or receiving (communicating) can be implemented across the multiple antennas 1014. Multi-antenna techniques can be implemented. By using a TX beam, the direction of signals transmitted by a transmitter of the communica- tion system is controlled. Energy is focused into a respective direction or even multiple direc- tions, by phase-coherent superposition of the individual signals originating from each an- tenna 1014. Thereby, a spatial data stream can be directed. The spatial data streams trans- mitted on multiple beams can be independent, resulting in spatial multiplexing multi-antenna transmission; or dependent on each other, e.g., redundant, resulting in diversity multi-input multi-output (MIMO) transmission. As a general rule, alternatively or additionally to such TX beams, it is possible to employ RX beams. According to examples, rank-1 communication is employed, i.e., only a single data stream per UE. FIG.7 illustrates a variant of the communication system 100. FIG.7 illustrates aspects with respect to communicating via a CED 109. A UE 102 is served by the BS 101 via the CED 109. Another UE 105 (that can be configured as the UE 102, cf. FIG.1, FIG.2, FIG.5, FIG.6) is also served by the BS 101 via the CED 109. Different steering vectors at the CED define TX and RX beams 671-672; only beam 671 is directed towards the UE 102. Beam 672 is directed towards the UE 105. Respective TX or RX beamformers are used at the CED 109. Also illustrated is a beam 679 of the CED 109 that is directed towards the BS 101 and can be accessed by respective RX or TX beamformers. In the disclosure it is assumed that the angles ^, ^ _^ are known and respective beam man- agement can be implemented at the nodes 101, 102, 105, 109. The BS 101 can co-schedule two UEs such as the UEs 102, 105 that are both rank-1 circular UEs, i.e., that both have a rank-1 circular polarized receiver or transmitter type (cf. TAB.1: option I; FIG.2). In such case, the BS 101 transmits, using H-POL on the beam 679, a data SYP349050WO01 13 E39500WO SN stream directed to the UE 102; and the BS 101 transmits, using V-POL on the beam 679, an- other data stream directed to the UE 105. Then, a first sub array of H-POL antenna elements of the CED 109 serves the UE 102 and a second sub-array of V-POL antenna elements of the CED 109 serves the UE 105, respectively employing the beam 671 of the beam 672. This is different when co-scheduling rank-1 linear and rank-1 circular UEs (cf. TAB.1: option III). Here, the BS 101 transmits signals that include a superposition of first signals intended for the first UE 102 and second signals intended for the second UE 105. In other words, a first component of transmit signals transmitted using H-POL includes a mixture / superposi- tion of signals for both UEs; likewise a second component of the transmit signals transmitted using V-POL includes another mixture of signals for both UEs 102, 105. Also illustrated in FIG.7 is a control node 108 that can communicate with the CED 109 on a control link 199. The control node 108 is generally optional. While the control node 108 is shown as a separate device, it would be possible that the control node 108 is implemented as a functionality of the BS 101 or one of the UEs 102, 105. FIG.8 illustrates aspects in connection with the CED 109. The CED 109 includes an array 690 of antenna elements 1094 each imposing a respective configurable antenna-element- specific phase shift when transmitting or receiving incident electromagnetic waves and op- tionally an antenna-element-specific amplification; this defines a respective spatial filter. The array 690 includes two subarray 691, 692, one for H-POL and one for V-POL. Typically, the CED 109 includes multiple antenna arrays (albeit in FIG.8 only a single array is illustrated), e.g., separate antenna arrays for TX and RX (TX array and RX array) The role of the multiple antenna arrays can be switched; e.g., one array may operate as TX array first and then as RX array, or vice versa. Also illustrated is an RF/IF signal processing module 670. At the RF/IF signal processing module 670, the RF signals associated with each antenna element 1094 can be processed, e.g., up- and/or down-converted from/to the baseband, combined with each other, split up, phase shifts can be applied, amplification can be applied, etc. The order of these signal pro- cessing steps can vary, depending on the implementation. It is possible that the signal pro- cessing is restricted to the analog domain. The CED 109 may not include an analog-to-digital converter for processing the received sig- nals. Digital-domain forward-error correction may not be provided for. The (re-)configuration of antenna elements 1094 defines respective TX or RX beamformers and accordingly the corresponding beams (cf. FIG.7). The re-configuration of the antenna elements 1094 also defines the beam-splitting ratios (A-values). The CED 109 includes an antenna interface 1095 and a processor 1091 that can set respec- tive antenna weights, i.e., antenna-element-specific amplitude gains and phase shifts. Further, there is a communication interface 1092 such that communication on a control link 199 can be established between the CED 109 and a remote device, e.g., the BS 101 or the control node 108 (cf. FIG.3). The processor 1091 can load program code from a non-volatile memory 1093 and execute the program code. Executing the program code causes the processor to per-form techniques as described herein, e.g.: re-configuring each one of the antenna elements 1094 to activate SYP349050WO01 14 E39500WO SN one of multiple spatial filters, i.e., to activate a certain TX or RX beamformer, e.g., based on beam-splitting ratios (A-values), etc. While FIG.8 illustrates an CED 109, as a general rule, similar techniques may be applied with other types of CEDs. FIG.9 is a flowchart of a method according to various examples. For instance, the method of FIG.9 can be executed by a BS of a cellular network, e.g., by the BS 101. For instance, the method of FIG.9 may be executed by the processor 1011 of the BS 101 upon loading pro- gram code from the memory 1015 and upon executing the program code. At box 3005, the BS requests from all UEs currently served via a CED respective polarization indications that are indicative of whether the respective UE includes a rank-1 linear polarized receiver or transmitter type, or whether the respective UE rather includes a rank-1 circular polarized receiver or transmitter type. Respective aspects of different receiver types have been disclosed above in connection with FIG.1 and FIG.2. The polarization indication is thus indicative of ^ _^ . For instance, box 3005 may be triggered by a scheduling procedure for scheduling these UEs that are currently served via the CED to a time-frequency resources of a shared chan- nel, e.g., a downlink or uplink shared channel. It is optionally possible at box 3010 to reconfigure the receiver or transmitter types at at least one of the UEs. For instance, it would be possible, as part of box 3010, to request from the UEs a respective capability indication that is indicative of whether the respective UE is capa- ble of switching between different rank-1 receiver or transmitter types, e.g., from rank-1 linear polarized receiver type to rank-1 circular polarized receiver type (e.g., from FIG.1 configura- tion to FIG.2 configuration or vice versa). Then, based on such capability indications and as part of the scheduling procedure, it would be possible to request at least one of the UEs to switch to a different rank-1 receiver or transmitter type. By such techniques, it would be pos- sible to have the same number of rank-1 linear polarized receiver types and rank-1 circular polarized receiver types, which enables co-scheduling of respective pairs. Thereby, the over- all transmission efficiency across the ensemble of UEs can be increased. At box 3015, it is then possible to co-schedule pairs of UEs to respective shared blocks of time-frequency resources based on the polarization indications obtained at box 3005 or op- tionally taking into account the reconfiguration at box 3010. Specifically, it is possible to co- schedule pairs of UEs that include one rank-1 linear polarized UE and one rank-1 circular po- larized UE; or two rank-1 circular polarized UEs. Next, at box 3020, the channels between the CED and each one of the UEs of a given pair are estimated. This includes determining the relative orientation of the UEs with respect to the CED; i.e., in other words, the g-values of Equation 6 are determined. There are various options for estimating the channels. For instance, a channel sounding pro- cedure may be employed. This can include communication of reference signals in the uplink or in the downlink when a respective spatial filter is activated at the CED 109 that uses a beam to one of the two UEs, respectively (cf. FIG.7: the CED 109 could be configured to use a spatial filter that uses the beam 671 for H-POL and V-POL; then reference signals can be communicated using H-POL and V-POL between the BS 101 and the UE 102 to determine SYP349050WO01 15 E39500WO SN ^ _^ , ^ _^ for that UE, respectively; the same can be repeated for the UE 105 using the beam 672). It would also be possible to obtain respective orientation indications from the UEs that are indicative of a relative orientation of the respective UE with respect to the CED. Then, the g-values can be calculated based on these orientation indications. Then, at box 3025, it is possible to determine the transmit precoders for transmitting of sig- nals at the BS, based on these channels that have been determined at box 3020. For in- stance, zero-forcing precoders can be determined. Dirty paper precoders can be determined. Minimum mean square error (MMSE) vector precoding, vector perturbation are further exam- ples of precoders. Likewise receive precoders can be determined. At box 3025, the beam splitting ratios of the CED are also determined, based on the esti- mates of the channel between the CED and the UEs of a given pair of UEs. These beam- splitting ratios impact the overall signal arriving at each UE and, accordingly, the transmit precoders can be determined based on the beam-splitting ratios. More specifically, the transmit precoders in the beam-splitting ratios can be determined based on a numerical optimization that varies the beam-splitting ratios, as explained above in connection with Equation 6. This numerical optimization can include constraints that are as- sociated with the physical limitations of the CED to implement the beam splitting ratios. Ex- ample constraints have been disclosed in connection with TAB.2. The numerical optimiza- tion includes a goal function that rewards, e.g., the low transmit power as explained in con- nection with Equation 6 and/or the overall data throughput between the BS and the UEs that are co-scheduled. Once the beam-splitting ratios have been determined, it is possible to configure the CED 3030 to implement the beam-splitting ratios. For this, spatial filters for both polarizations of the CED can be determined. I.e., the antenna weights for all antenna elements of the two an- tenna arrays can be determined. There prior art techniques known to determine the spatial filters of the CED based on the beam-splitting ratios. Some techniques are reproduced in An- nex 1 at the end of the disclosure. The determination of the spatial filters of the CED based on the beam-splitting ratios can be executed at the BS; in which the BS would then provide the spatial filters to the CED once determine. Alternatively, it would also be possible that the CED or a control node thereof de- termines the spatial filters in which the BS would provide the beam-splitting ratios to the CED or its control node to determine the spatial filters. Then, at box 3035, once the CED has been configured appropriately and the precoders of the BS have been determined, it is possible to transmit, on a shared block of time-frequency resources and towards the CED, transmit signals that include a superposition of signals for the paired UEs. In detail, a first component of the transmit signals has a first transmit polari- zation and a second component of the transmit signals has a second transmit polarization that is different than the first transmit polarization. The first component includes a mixture of the first signals and the second signals and the second component includes a further mixture of the first signals and the second signals (cf. Equation 3).Likewise, assuming reciprocity, it would be possible to receive such receive signals that include a superposition of signals from the paired UEs. SYP349050WO01 16 E39500WO SN FIG.10 is a signaling diagram of communication between the CED 109, the BS 101 and mul- tiple UEs 102, 105, 106 according to various examples. While in the scenario of FIG.10 the CED 109 participates in the communication, in other examples, a control node 108 associ- ated with the CED 109 may participate in the communication (cf. FIG.7). At 5005, the CED 109 indicates its capability to implement polarization-based MDT. For in- stance, this can be associated with the capability to implement respective spatial filters. This can be associated with the capability of determining the spatial filters based on the beam- splitting ratios (A-values). This can correlate with the CED 109 including multiple sub-arrays that are associated with different the oriented polarizations. At 5010, the BS 101 requests the UEs 102, 105, 106 to provide an indication indicated for of whether the respective UE includes a certain rank-1 receiver type, e.g., linear polarized or circular polarized. At 5020, the UEs 102, 105, 106 provide the respective indication 4015 to the BS 101. Accordingly, 5010 and 5020 implement 3005 of the method of FIG.9. Then, the BS 101 co-schedules pairs of UEs, so that – e.g. (cf. TAB.1: option III) – each pair includes a first rank-1 receiver type and a second rank-1 receiver type, e.g., linear polarized and circular polarized UEs. This corresponds to box 3015. Once the pairs of UEs have been co-scheduled, the subsequent operation is illustrated in the signaling diagram of FIG.11. In connection with FIG.11, it is assumed that all nodes are aware of their spatial beams. How the spatial beams are aligned is out of scope of this dis- closure. This means, in particular, that the BS 101 determines a transmit or receive beam di- rected towards the CED 109. This also means that each one of the UEs 102, 105 – here forming a pair 199 – determine respective transmit and receive beams towards the CED 109. Also, the CED beams linking the BS 101 to the UE 102 and the BS 101 to the UE 105, re- spectively, are determined. Accordingly, at 5105, the BS 101 can provide a configuration 4105 to the CED 109, wherein this configuration is indicative of the corresponding beams 671, 672, 679 (cf. FIG.7). The corresponding spatial filter can be applied at the CED 109. Then, at 5110, channel sounding signals 4110 can be communicated. This can include, e.g., downlink reference signals, for the different configurations of the CED 109 (pointing towards the UE 102 and pointing towards the UE 105, respectively); an uplink report provided by the UEs 102, 105 to the BS 101. Based on this, the BS can then determine, at 5111, the precod- ing and the beam-splitting ratios (A-variables); this corresponds to box 3025. At 5115, a further configuration 4115 can be provided to the CED 109. This configuration 4115 can be either indicative of the beam-splitting ratios so that the CED 109 can determine the appropriate spatial filters on its own; or the spatial filters can be predetermined and the BS 101 and then indicated to the CED 109 using the configuration 4115. At 5120, it is then possible to transmit signals 4120 from the BS 101 to the UE 102 and the UE 105; or vice versa uplink signals 4120 from the UEs 102, 105 to the BS 101. The signals can be transmitted in time-frequency resources are shared channel such as the physical downlink shared channel the physical uplink shared channel. SYP349050WO01 17 E39500WO SN Although the invention has been shown and described with respect to certain preferred em- bodiments, equivalents and modifications will occur to others skilled in the art upon the read- ing and understanding of the specification. The present invention includes all such equiva- lents and modifications and is limited only by the scope of the appended claims. ANNEX I: DETERMINING SPATIAL FILTER FOR BEAM SPLITTING We consider a CED with ^ elements and let ^ → ∞. Further, we assume beam splitting in two randomly selected directions drawn from a uniform power density function over the half sphere. Let ^ _^ and ^ _^ denote steering vectors in said two directions. If the CED has a rectangular shape, then the elements in the two steering vectors traverse the said rectangular shape in a particular order which is not relevant for subsequent derivations. The steering vector from the CED to the BS is denoted by ^ _^ . Define ^ _^ = ∘ ^ _^ and ^ _^ = ^ _^ ∘ ^ _^ , where ∘ is Hadamard product. The CED applies a beamforming vector ^. Then, the signal arriving at UE-1 and UE-2 reads ^ ^ ^^ _^ = ^ ^ _^ ^ _^,^ and ^^ _^ = ^ ^ _^ ^ _^,^ . ^^^ ^^^ Our goal is to select ^ such that we can obtain desired phases and amplitudes of ^^ _^ and ^^ _^ . We separate this into two cases, (i) phase control only at the CED, i.e., ^| ^ _^ ^| = 1, ∀^, and (ii) phase and relative amplitude control, i.e., ^‖ ^ ^{‖^} = ^. We start off with (i) We can achieve this by using the beam splitting formula In this formula, 0 ≤ ^ ≤ 1. This defines the spatial filter Let us now consider the normalized signals ^ _^ = ^{^^} _^ ^ emanating from this beam split formula. We can write these as where we explicitly denoted the dependency on ^. As ^ → ∞ and the directions are drawn randomly from a uniform power density function over the half-sphere we can show, after lengthy but standard manipulations, ^ _^ (^) → ^ _^ ^ _^ (^) → ^ _^ (^) ^ _^ (^) → ^ _^ (^) where ^ _^ ⁽ _^ ⁾ _{= ^^} ⁽ _{1 − ^} ⁾ SYP349050WO01 18 E39500WO SN In the above, ^ ⁽ ^ ⁾ is the complete elliptic integral of the first kind and ^(^) is the complete elliptic integral of the second kind. I.e., Let ^^ = ^ ^ ^ ^ ^ ^ ^ _^ (^) and ^ _^ = ^ _^ (^). We can then express ^ _^ as function of ^ _^ as with where ^ ^{^^} ⋅ is the inverse of ^^ = ^^(^) (the function ^ ^ ^{( )} _{^ ^} ^ _^ (⋅) is injective over 0 ≤ ^ ≤ 1). Next, we move to (ii) We can achieve this by using the beam splitting formula Using the same notation and assumptions as for case (i), and after lengthy derivations, one can show that for this case, ^^ ^ = 1 − ^^ ^ . In particular, the following EXAMPLEs have been disclosed herein: EXAMPLE1. A method of operating an access node (101) of a communications network, the access node (101) communicating wirelessly with a plurality of wireless communication devices (102, 105, 106) via a coverage enhancing device (109), wherein the method comprises: - requesting (3005), from each wireless communication device (102, 105, 106) of the SYP349050WO01 19 E39500WO SN plurality of wireless communication devices (102, 105, 106), a respective polarization indica- tion (4015) indicative of whether the respective wireless communication device (102, 105, 106) comprises a first rank-1 receiver (551) or transmitter type or a second rank-1 receiver (552) or transmitter type, the first rank-1 receiver or transmitter type being configured to re- ceive or transmit a linear polarization, the second rank-1 receiver or transmitter type being configured to receive or transmit a circular polarization. EXAMPLE 2. The method of EXAMPLE 1, wherein said requesting (3005) is triggered by a scheduling procedure for scheduling the plurality of wireless communication devices (102, 105, 106) to time-frequency resources of a downlink or uplink shared channel. EXAMPLE 3. The method of EXAMPLE 1 or 2, further comprising: - based on the polarization indications, co-scheduling (3015) pairs (199) of wireless communication devices (102, 105) of the plurality of wireless communication devices (102, 105, 106) to respective shared blocks of the time-frequency resources. EXAMPLE 4. The method of EXAMPLE 3, wherein each pair (199) comprises a respective first wireless communication device comprising the first rank-1 receiver or transmitter type and a second wireless communication device comprising the second rank-1 receiver or transmitter type. EXAMPLE 5. The method of EXAMPLE 3, wherein each pair (199) comprises a respective first wireless communication device comprising the second rank-1 receiver or transmitter type and a second wireless communica- tion device comprising the second rank-1 receiver or transmitter type. EXAMPLE 6. The method of any one of the preceding EXAMPLEs, further comprising: - transmitting, on a shared block of time-frequency resources and towards the cover- age enhancing device, transmit signals (4120) comprising a superposition of first signals for a first wireless communication device of the plurality of wireless communication devices and second signals for a second wireless communication device of the plurality of wireless com- munication device, wherein the first wireless communication device comprises the first rank-1 receiver type, wherein the second wireless communication device comprises the second rank-1 re- ceiver type. EXAMPLE 7. The method of EXAMPLE 6, wherein a first component of the transmit signals (4120) has a first transmit polariza- tion, wherein a second component of the transmit signals has a second transmit polariza- tion different than the first transmit polarization, wherein the first component comprises a mixture of the first signals and the second signals, wherein the second component comprises a further mixture of the first signals and the second signals. SYP349050WO01 20 E39500WO SN EXAMPLE 8. The method of EXAMPLE 6 or 7, further comprising: - estimating (3020) a first channel between the coverage enhancing device (109) and the first wireless communication device (102, 105), - estimating (3020) a second channel between the coverage enhancing device (109) and the second wireless communication device (102, 105), and - determining transmit precoders for said transmitting of the signals based on the first channel and the second channel. EXAMPLE 9. The method of EXAMPLE 8, further comprising: - determining (3025) beam-splitting ratios for the coverage enhancing device based on the first channel and the second channel, the beam-splitting ratios defining a relationship between output signals forwarded by the coverage enhancing device to the first wireless communication device and the second wireless communication device respectively, and inci- dent signals arriving at the coverage enhancing device having a first receive polarization and a second receive polarization respectively, wherein the transmit precoders are determined based on the beam-splitting ratios. EXAMPLE 10.The method of EXAMPLE 9, further comprising: - providing the beam-splitting ratios to the coverage enhancing device (109) or an as- sociated control node (108), to enable the coverage enhancing device or the control node to determine spatial filters (671, 672) for the first polarization and the second polarization. EXAMPLE 11.The method of EXAMPLE 9, further comprising: - based on the beam-splitting ratios, determining a first spatial filter and a second spa- tial filter for the coverage enhancing device, the first spatial filter being associated with the first receive polarization and the second spatial filter being associated with second receive polarization, and - providing the first spatial filter (671, 672) and the second spatial filter (671, 672) to the coverage enhancing device (109) or an associated control node (108). EXAMPLE 12.The method of any one of EXAMPLEs 9 to 11, wherein the transmit precoders and the beam-splitting ratios are determined based on a numerical optimization that varies the beam-splitting ratios. EXAMPLE 13.The method of EXAMPLE 12, wherein the numerical optimization comprises one or more constraints associated with physical limitations of the coverage enhancing device (109) to implement the beam-split- ting ratios. EXAMPLE 14.The method of EXAMPLE 12 or 13, wherein the numerical optimization comprises a goal function that rewards at least one of low transmit power at the access node (101) or overall data throughput between the access node (101) and the first and second wireless communication devices (102, 105, 106). EXAMPLE 15.The method of any one of EXAMPLEs 8 to 14, wherein said estimating of the first channel and said estimating of the second channel is based on a channel sounding procedure (4110). EXAMPLE 16.The method of any one of EXAMPLEs 8 to 15, further comprising: - obtaining, for the first wireless communication device (102, 105) and the second SYP349050WO01 21 E39500WO SN wireless communication device(102, 105), a respective orientation indication indicative of a relative orientation of the respective wireless communication device (102, 105) with respect to the coverage enhancing device (109), wherein said estimating of the first channel and said estimating of the second channel is based on the orientation indications. EXAMPLE 17.The method of any one of the preceding EXAMPLEs, further comprising: - requesting (3010), from each wireless communication device (102, 105, 106) of the plurality of wireless communication devices (102, 105, 106), a respective capability indication indicative of whether the respective wireless communication device (102, 105, 106) is capa- ble to switch between different rank-1 receiver (551, 552) or transmitter types. EXAMPLE 18.The method of EXAMPLE 17, further comprising: - based on the capability indications and as part of a scheduling procedure for sched- uling the plurality of wireless communication devices (102, 105, 106) to time-frequency re- sources of a shared channel, requesting (3010) at least one wireless communication device (102, 105, 106) of the plurality of wireless communication devices (102, 105, 106) to switch to a different rank-1 receiver (551, 552) or transmitter type. EXAMPLE 19.An access node (101) of a communications network, the access node (101) being configured to communicate wirelessly with a plurality of wireless communication de- vices (102, 105, 106) via a coverage enhancing device (109), wherein the access node comprises at least one processor and a memory, wherein the at least one processor, upon loading program code from the memory and upon executing the program code, is configured to: - request (3005), from each wireless communication device (102, 105, 106) of the plu- rality of wireless communication devices (102, 105, 106), a respective polarization indication (4015) indicative of whether the respective wireless communication device (102, 105, 106) comprises a first rank-1 receiver (551) or transmitter type or a second rank-1 receiver (552) or transmitter type, the first rank-1 receiver or transmitter type being configured to receive or transmit a linear polarization, the second rank-1 receiver or transmitter type being configured to receive or transmit a circular polarization. EXAMPLE 20.The access node of EXAMPLE 19, wherein the at least one processor, upon executing the program code, is further configured to perform the method of any one of EX- AMPLEs 1 to 18.