Configuration of interference measurement resource

Abstract

Systems and methods are disclosed that relate to configuration of interference measurement resources in a wireless communications system. A method performed by a User Equipment (UE) comprises receiving, from a network node, downlink control information that schedules a downlink channel transmission to the UE, wherein a number (N≥1) of demodulation reference signal (DMRS) ports are allocated for the scheduled downlink channel transmission to the UE. The method further comprises receiving, from the network node, an indication that indicates either: a total number (T) of allocated DMRS ports for the scheduled downlink channel transmission to the UE and one or more additional scheduled downlink transmissions to one or more other UEs, if any, or a number (Y) of DMRS ports available for inter-cell interference estimation. The method further comprises determining, based on the received indication, a set of DMRS ports available to the UE for intra-cell interference estimation.

Description

[0001] CONFIGURATION OF INTERFERENCE MEASUREMENT RESOURCE

[0002] RELATED APPLICATIONS

[0003] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 689,813, filed September 2, 2024, the disclosure of which is hereby incorporated herein by reference in its entirety.

[0004] TECHNICAL FIELD

[0005] The present disclosure related to interference measurement in Radio Access Network (RAN) of a cellular communications system.

[0006] BACKGROUND

[0007] In the time domain, 3rdGeneration Partnership Project (3GPP) New Radio (NR) downlink (DL) and uplink (UL) transmissions are organized into equally sized subframes of 1 millisecond (ms) each. A subframe is further divided into multiple slots of equal duration. The slot length depends on subcarrier spacing. For 15 kilohertz (kHz) subcarrier spacing, there is only one slot per subframe. In general, for 15 ■ 2 kHz subcarrier spacing, where / / G {0,1, 2, 3, 4], there are 2 slots per subframe. Finally, each slot consists of 14 symbols (unless extended cyclic prefix is configured).

[0008] In the frequency domain, a system bandwidth is divided into Resource Blocks (RBs) each corresponding to twelve (12) contiguous subcarriers. One subcarrier during one symbol interval forms one Resource Element (RE).

[0009] Demodulation Reference Signal (DM-RS) for Physical Downlink Shared Channel (PDSCH) is an DL reference signal that consists of a pseudo-random Quadrature Phase-Shift Keying (QPSK) sequence Cyclic Prefix (CP)-Orthogonal Frequency Division Multiplexing (OFDM) or low-Peak-to-Average Power Ratio (PAPR) sequences for Discrete Fourier Transform (DFT) Spread OFDM (DFT-S-OFDM). DM-RS for PDSCH is used for demodulation of PDSCH such that the receiver (i.e., the User Equipment, UE) can handle time-varying and frequency- selective channels. DM-RS is confined to the scheduled PDSCH bandwidth and duration.

[0010] The mapping of DM-RS to REs is configurable in both frequency and time domain. In the frequency domain, there are two mapping types, namely, Type 1 (comb based) or Type 2 (noncomb based). In the time-domain, DM-RS can be either single symbol or double symbol, where the latter means that DM-RS is mapped in pairs of two adjacent symbols. Furthermore, a UE can be configured with one, two, three, or four single-symbol DM-RS and one or two double-symbol DM-RS. In low-Doppler scenarios, one DM-RS symbol may be sufficient whereas, in high- Doppler scenarios, additional DM-RS symbols are required.

[0011] Figures 1 A illustrates Type 1 single and double-symbol DM-RS, and Figure IB illustrates Type 2 single and double-symbol DM-RS. Figure 2 illustrates single-symbol DM-RS with two additional single-symbol DM-RS (left part of the figure) and double-symbol DM-RS with one additional double-symbol DM-RS (right part of the figure). Figure 2 is valid for DM-RS type 1 and front-loaded Physical Uplink Shared Channel (PUSCH) (i.e., PUSCH mapping type A) of duration 14 symbols.

[0012] 1.1.1.1

[0013] DM-RS for PDSCH is configured in Radio Resource Control (RRC) (see ASN code in 3GPP Technical Specification (TS) 38.331 version 16.1.0).

[0014] The DM-RS for PUSCH can be additionally and optionally configured with respect to scrambling identity (ID) 0 and 1, configured by RRC parameters scramblingIDO and scramblinglD 1 , respectively, which are used for generating the pseudo-random DM-RS sequence. 1.1.1.2

[0015] DM-RS ports are mapped to REs within one Code Division Multiplexing (CDM) group. DM-RS ports that belong to the same CDM group are separated by a length-2 Frequency Domain (FD)-Orthogonal Cover Code (OCC) (i.e., a FD-OCC-2) (and a length-2 Time Domain (TD)-OCC (i.e., a TD-OCC-2), for double-symbol DM-RS). In NR Release (Rel)-16, the DM-RS sequence is mapped to the following subcarriers (for DFT-S-OFDM, only DM-RS type 1 is supported): for type 1, for type 2.

[0016] Here, k is the subcarrier index (which starts / ends at the first / last subcarrier within the scheduled PUSCH bandwidth), n G {0,1,2, ... }, k' G {0,1}, and A is an offset that depends on the CDM group.

[0017] In Table 1 and Table 2 below, port-specific parameters for DM-RS type 1 and type 2 are shown. Here, wf(fc') , where k' G {0,1}, is the FD-OCC and wt(Z') , where V = 0 for singlesymbol DM-RS and I' G {0,1} for double-symbol DM-RS, is the TD-OCC. Note that DM-RS ports in different CDM groups are separated by different offsets and that DM-RS ports within the same CDM group are separated through coding.

[0018] Table 1 : Parameters for PUSCH DM-RS configuration type 1 (reproduced from Table

[0019] 6.4.1.1.3-1 of 3GPP TS 38.211). Here, p denotes the DM-RS port.

[0020] Table 2: Parameters DM-RS configuration type 2 (reproduced from PUSCH DMRS Table

[0021] 6.4.1.1.3-2 of 3GPP TS 38.211). Here, p denotes the DM-RS port. From the transmitter’s perspective, the number of DM-RS ports used for PDSCH transmission coincides with the transmission rank, i.e., one DM-RS port per transmitted layer. The DM-RS port mapping is signaled to the UE from the NR base station (i.e., the gNodeB, gNB) via Downlink Control Information (DCI). Table 3 and Table 4 below show what such indication looks like for DCI format 0 1, CP-OFDM, single-symbol DM-RS type 1, and for transmission rank 1 and 2, respectively. Similar tables can be found in 3GPP 38.212 for rank 3 and 4, double-symbol DM-RS, and for DM-RS type 2. subcarriers, which are associated with a CDM group, that are not used for DM-RS can be used for PUSCH. After layer mapping, the DM-RS and the associated PUSCH are mapped to physical antennas through precoding.

[0022] Table 3: Antenna ports for single-symbol DM-RS type 1, transform precoding is disabled, rank-1 transmission (reproduced from Table 7.3.1.1.2-8 of 3GPP 38.212).

[0023] Table 4: Antenna ports for single-symbol DM-RS type 1, transform precoding is disabled, rank-2 transmission (reproduced from Table 7.3.1.1.2-9 of 3GPP 38.212). When receiving PDSCH scheduled by DCI format 1 1, the UE assumes that the CDM groups indicated in the configured index from Tables 7.3.1.2.2-1 (reproduced below as Table 5 as an example), 7.3.1.2.2-2, 7.3.1.2.2-3, 7.3.1.2.2-4 of 3GPP TS 38.212 contain potential coscheduled downlink DM-RS and are not used for data transmission, where " 1 ", "2" and "3 " for the number of DM-RS CDM group(s) in Tables 7.3.1.2.2-1, 7.3.1.2.2-2, 7.3.1.2.2-3, 7.3.1.2.2-4 of 3GPP TS 38.212 correspond to CDM group 0, {0,1 }, {0,1,2}, respectively. For DM-RS configuration type 1, if a UE is scheduled with one codeword and assigned with the antenna port mapping with indices of {2, 9, 10, 11 or 30} in Table 7.3.1.2.2-1 and Table 7.3.1.2.2-2 of clause 7.3.1.2 of 3GPP TS 38.212, or if a UE is scheduled with two codewords, the UE may assume that all the remaining orthogonal antenna ports are not associated with transmission of PDSCH to another UE.

[0024] Table 5: Antenna port(s) (1000 + DMRS port), dmrs-Type= \ , maxLength= (reproduced from

[0025] Table 7.3.1.2.2-1 of 3GPP TS 38.212) In NR, an interference and noise estimation resource (aka an Interference Measurement

[0026] Resource, IMR) is defined for Channel Quality Index (CQI) calculations, for Channel State Information (CSI) reporting, (herein denoted CSI-IMR).

[0027] However, for PDSCH demodulation, such IMR (herein denoted PDSCH-IMR) does not exist in NR (or 3GPP Long Term Evolution (LTE)). How and based on what an LTE or NR UE estimates interference and noise for demodulation of data channel is undefined and up to UE implementation.

[0028] SUMMARY

[0029] Systems and methods are disclosed that relate to configuration of interference measurement resources in a wireless communications system. In one embodiment, a method performed by a User Equipment (UE) comprises receiving, from a network node, downlink control information that schedules a downlink channel transmission to the UE, wherein a number (N>1) of demodulation reference signal (DMRS) ports are allocated for the scheduled downlink channel transmission to the UE. The method further comprises receiving, from the network node, an indication that indicates either: a total number (T) of allocated DMRS ports for the scheduled downlink channel transmission to the UE and one or more additional scheduled downlink transmissions to one or more other UEs, if any, or a number (Y) of DMRS ports available for intercell interference estimation. The method further comprises determining, based on the received indication, a set of DMRS ports, other than the DMRS ports allocated for the scheduled downlink transmission to the UE, available to the UE for intra-cell interference estimation. Embodiments of the present disclosure avoid the need for blind detection of used DMRS ports for UE implementation, leading to lower complexity, lower UE power consumption, and much lower risk for misdetection and thereby better downlink throughput performance and latency.

[0030] In one embodiment, the received indication indicates the total number (T) of allocated DMRS ports for the UE and the one or more other UEs. In one embodiment, there are M available DMRS ports indexed as DMRS ports X to X+M-l where M>T, and the allocated DMRS ports for the UE and the one or more other UEs are DMRS ports X to X+T-l. In one embodiment, the determined set of DMRS ports available to the UE for intra-cell interference estimation consists of T-N DMRS ports from among DMRS ports X to X+T-l other than the N DMRS ports allocated for the scheduled downlink channel transmission to the UE. In one embodiment, the method further comprises determining that DMRS ports X+T to X+M-l can be used by the UE for intercell interference estimation.

[0031] In one embodiment, the received indication indicates the number (Y) of DMRS ports available for inter-cell interference estimation. In one embodiment, there are M available DMRS ports indexed as DMRS ports X to X+M-l, and the allocated DMRS ports for the UE and the one or more other UEs are DMRS ports X to X+M-Y-l. In one embodiment, the determined set of DMRS ports available to the UE for intra-cell interference estimation consists of M-Y-N DMRS ports from among DMRS ports X to X+M-Y-l other than the N DMRS ports allocated for the scheduled downlink channel transmission to the UE. In one embodiment, the method further comprises determining that DMRS ports X+M-Y to X+M-l can be used by the UE for inter-cell interference estimation.

[0032] In one embodiment, the received indication, N, and an indication of a first DMRS port allocated for the scheduled downlink channel transmission to the UE are jointly encoded.

[0033] In one embodiment, the method further comprises receiving, from the network node, additional information that indicates whether a DMRS sequence used for the DMRS port(s) allocated for the scheduled downlink channel transmission to the UE is the same as that used for the DMRS ports allocated for the one or more additional scheduled downlink channel transmissions for the one or more other UEs.

[0034] In one embodiment, determining the set of DMRS ports, other than the DMRS ports allocated for the scheduled downlink transmission to the UE, available to the UE for intra-cell interference estimation comprises determining the set of DMRS ports, other than the DMRS ports allocated for the scheduled downlink transmission to the UE, available to the UE for intra-cell interference estimation without blind DMRS decoding.

[0035] In one embodiment, the method further comprises performing intra-cell interference estimation using at least a subset of the determined set of DMRS ports.

[0036] In one embodiment, the UE assumes that, in the case of MU-MIMO, DMRS ports scheduled for the UE and any other UEs that are also scheduled for downlink transmission are indexed via consecutive DMRS number numbers and that a lowest numbered DMRS port is always used.

[0037] Corresponding embodiments of a UE are also disclosed. In one embodiment, a UE is configured to receive, from a network node, downlink control information that schedules a downlink channel transmission to the UE, wherein a number (N>1) of DMRS ports are allocated for the scheduled downlink channel transmission to the UE. The UE is further configured to receive, from the network node, an indication that indicates either: a total number (T) of allocated DMRS ports for the scheduled downlink channel transmission to the UE and one or more additional scheduled downlink transmissions to one or more other UEs, if any, or a number (Y) of DMRS ports available for inter-cell interference estimation. The UE is further configured to determine, based on the received indication, a set of DMRS ports, other than the DMRS ports allocated for the scheduled downlink transmission to the UE, available to the UE for intra-cell interference estimation.

[0038] In one embodiment, a UE comprises a communication interface comprising a transmitter and a receiver. The UE further comprises processing circuitry associated with the communication interface. The processing circuitry is configured to cause the UE to receive, from a network node, downlink control information that schedules a downlink channel transmission to the UE, wherein a number (N>1) of DMRS ports are allocated for the scheduled downlink channel transmission to the UE. The processing circuitry is further configured to cause the UE to receive, from the network node, an indication that indicates either: a total number (T) of allocated DMRS ports for the scheduled downlink channel transmission to the UE and one or more additional scheduled downlink transmissions to one or more other UEs, if any, or a number (Y) of DMRS ports available for inter-cell interference estimation. The processing circuitry is further configured to cause the UE to determine, based on the received indication, a set of DMRS ports, other than the DMRS ports allocated for the scheduled downlink transmission to the UE, available to the UE for intracell interference estimation.

[0039] Embodiments of a method performed by a network node are also disclosed. In one embodiment, a method performed by a network node comprises transmitting, to a UE, downlink control information that schedules a downlink channel transmission to the UE, wherein a number (N) of DMRS ports are allocated for the scheduled downlink channel transmission to the UE. The method further comprises transmitting, to the UE, an indication that indicates either: a total number (T) of allocated DMRS ports for the scheduled downlink channel transmission to the UE and one or more additional scheduled downlink transmissions to one or more other UEs, if any, or a number (Y) of DMRS ports available for inter-cell interference estimation.

[0040] Corresponding embodiments of a network node are also disclosed. In one embodiment, a network node is configured to transmit, to a UE, downlink control information that schedules a downlink channel transmission to the UE, wherein a number (N) of DMRS ports are allocated for the scheduled downlink channel transmission to the UE. The network node is further configured to transmit, to the UE, an indication that indicates either: a total number (T) of allocated DMRS ports for the scheduled downlink channel transmission to the UE and one or more additional scheduled downlink transmissions to one or more other UEs, if any, or a number (Y) of DMRS ports available for inter-cell interference estimation.

[0041] In one embodiment, a network node comprises processing circuitry configured to cause the network node to transmit, to a UE, downlink control information that schedules a downlink channel transmission to the UE, wherein a number (N) of DMRS ports are allocated for the scheduled downlink channel transmission to the UE. The processing circuitry is further configured to cause the network node is to transmit, to the UE, an indication that indicates either: a total number (T) of allocated DMRS ports for the scheduled downlink channel transmission to the UE and one or more additional scheduled downlink transmissions to one or more other UEs, if any, or a number (Y) of DMRS ports available for inter-cell interference estimation.

[0042] BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the disclosure, and together with the description serve to explain the principles of the disclosure.

[0044] Figure 1A illustrates Type 1 single and double-symbol Demodulation Reference Signal (DM-RS);

[0045] Figure IB illustrates Type 2 single and double-symbol DM-RS;

[0046] Figure 2 illustrates single-symbol DM-RS with two additional single-symbol DM-RS (left part of the figure) and double-symbol DM-RS with one additional double-symbol DM-RS (right part of the figure). Figure 2 is valid for DM-RS type 1 and front-loaded Physical Uplink Shared Channel (PUSCH) (i.e., PUSCH mapping type A) of duration 14 symbols

[0047] Figure 3 illustrates the operation of a User Equipment (UE) and a network node in accordance with embodiments of the present disclosure;

[0048] Figure 4 shows an example of a communication system in accordance with some embodiments of the present disclosure;

[0049] Figure 5 shows a UE in accordance with some embodiments of the present disclosure;

[0050] Figure 6 shows a network node in accordance with some embodiments of the present disclosure; and

[0051] Figure 7 is a block diagram illustrating a virtualization environment in which functions implemented by some embodiments may be virtualized in accordance with some embodiments of the present disclosure.

[0052] DETAILED DESCRIPTION

[0053] The embodiments set forth below represent information to enable those skilled in the art to practice the embodiments and illustrate the best mode of practicing the embodiments. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure. Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

[0054] There currently exist certain challenge(s). A wireless communication receiver, such as the User Equipment (UE) in 3rdGeneration Partnership Project (3GPP) New Radio (NR), needs to make an estimate of both the desired signal strength level and the noise and interference signal strength level for the channel decoder to function properly, e.g., for spatial interference suppression using multiple receive antennas.

[0055] In NR, the 3 GPP specification provides that the UE can, from the Physical Downlink Shared Channel (PDSCH) scheduling control message (i.e., the Downlink Control Information (DCI)), sometimes assume that some other Demodulation Reference Signal (DMRS) ports (i.e., ports not used for the scheduled PDSCH) potentially are used by the network (NW) in simultaneously (co-scheduled) transmission of PDSCH to other users, i.e., are potentially used by the NW for so called Multi-User Multiple Input Multiple Output (MU-MIMO) operation. The UE then needs to blindly detect whether other DMRS ports actually are used or not, which can be a complex task prone to misdetection which leads to suboptimal performance. This is a problem with the existing solution.

[0056] A straightforward alternative would be to explicitly and dynamically indicate which other ports are used, but this requires high overhead in DCI since the used DMRS ports need to be signaled to the UE, not only for the UE’s “own” PDSCH but also for every other co-scheduled PDSCH. It becomes a combinatorial problem with many alternatives.

[0057] Suppose a UE in NR is scheduled 1 port out of 8 possible ports. Then, there are X possible ways to select 0 up to 7 ports among the remaining ports and thus [log2X] bits = 7 bits (or equivalently a bitmap of 7 bits) is needed to indicate the combination of ports occupied by coscheduled users, using a “straightforward” approach, which causes a large overhead problem for DCI signaling. Here, or equivalently

[0058] X = 27= 128.

[0059] Certain aspects of the disclosure and their embodiments may provide solutions to these or other challenges. In a first general aspect, a restriction is introduced, known to the NW and the UE, that the numbers for DMRS ports associated with co-scheduled UEs are using consecutive integers and that the lowest numbered port is always used. In a second general aspect, information is signaled (e.g., in DCI) from the NW to the UE that informs the UE of the total number of scheduled DMRS ports for the co-scheduled UEs

[0060] In some embodiments, these two general aspects are used together to enable any coscheduled UE to know precisely which other DMRS ports are used without the need for blind detection.

[0061] In a further embodiment, additional information is signaled from the network to the UE that informs the UE whether the DMRS sequence of co-scheduled UEs can be assumed to be the same as the DMRS sequence of the scheduled PDSCH DMRS, or a different sequence.

[0062] Certain embodiments may provide one or more of the following technical advantage(s). Embodiments of the present disclosure avoid the need for blind detection of used DMRS ports for UE implementation, leading to lower complexity, lower UE power consumption, and much lower risk for misdetection and thereby better downlink throughput performance and latency. Embodiments of the solution disclosed herein provide low overhead signaling (e.g., in DCI), compared to the “straightforward” approach discussed above. The teachings of certain embodiments may improve downlink throughput performance and latency of the radio access network (RAN) and lower UE power consumption.

[0063] The aforementioned problem with the existing solution is solved by observing that the standardized DMRS antenna port indication table (e.g., used in NR) has a lot of flexibility that is not needed. For example, it is possible to schedule two UEs with rank 1 each, using port 3 and 6.

[0064] Embodiments the solution disclosed herein introduce a scheduling restriction that, in MU- MIMO, the scheduler at the network node should not select DMRS ports that are not adjacent for the UEs and the scheduler should always start from the lowest numbered DMRS port. For example, in a scenario in which there are M available DMRS ports numbered from DMRS port 0 to DMRS port M-l, the scheduler must select port 0 and 1 for the two co-scheduled UEs, in the example given here. Secondly, information is signaled (e.g., in DCI) from the network to the UE that informs the UE of the total number T of scheduled DMRS ports among all the co-scheduled UEs. If a DMRS port table with 8 entries is configured to the UEs (i.e., if there are M=8 available DMRS ports), then T has a value range from 1 to 8; hence, T can be conveyed in DCI using 3 bits.

[0065] By using the aforementioned scheduling restriction and the signaled information together, any co-scheduled UE knows precisely which other DMRS ports are used without the need for blind detection. In the example above, T=2 and ports 0 and 1 are scheduled for the two UEs respectively. UE#2 that uses port 1 thus knows that port 0 is used by a co-scheduled UE, and UE#2 can thus coherently estimate the channel for e.g., Minimum Mean Square Error (MMSE) interference suppression of the associated interference. If a UE is scheduled N ports (i.e. a PDSCH of rank N) and T=N is indicated, then the UE knows that there are no co-scheduled UEs.

[0066] If a UE is scheduled N ports and T>N is indicated while T is still less than the total number of available ports M, then the UE may use the resources of the remaining M-T ports to estimate inter-cell interference (or more generally non-MU-MIMO interference) since these ports clearly do not contain any intra-cell (i.e. co-scheduled UE) interference (i.e., MU-MIMO interference). The UE can take this estimate into account in the MMSE / receiver algorithm as well.

[0067] For example, consider two UEs scheduled rank 1 with port 0 and 1 respectively, where T=2 and M=8. Then, in this example, the remaining 8-2= 6 DMRS port resources can be used to (non-coherently) estimate inter-cell interference from non-co-scheduled UEs. Hence, in this example, both UE1 and UE2 perform coherent channel estimation of port 0,1 while UE#1 uses port 0 for desired channel estimate and port 1 for interference and vice versa for UE#2. Both UEs use port 2, 3, 4, 5, 6, 7 for inter-cell interference estimation.

[0068] Note that a UE is scheduled a number of DMRS ports that is equal to the rank N of the PDSCH, starting with port Nstart and ending with port Nstart +N-1 where only one of the coscheduled UEs is indicated to use Nstart=0.

[0069] In an alternative embodiment, it is observed that the total number of available DMRS ports M is divided into three subsets, where a first subset contains the S ports of the desired channel (for PDSCH), a second subset contains I ports of the co-scheduled UEs, and a third subset contains the Y ports to be used for intercell interference estimation. Here S+I+Y = M and where T=S+I in previous embodiments. Since M is known from DMRS configuration and S is known from scheduling of the PDSCH (i.e. the rank), it is possible to indicate Y instead of T. In both cases, all values S,I,Y becomes known. Hence, in this alternative embodiment, Y is indicated in the scheduling instead of T.

[0070] In some embodiments, the total number of ports T (or alternatively the number of ports to be used for intercell interference estimation Y), the UE rank N, and the first DMRS port allocated to the UE (i.e., Nstart) are jointly encoded for further compression. This joint encoding can be done by utilizing correlation between the parameters, e.g. that N <= T and Nstart - N <= T. The UE may also have a highest rank lower than T reducing the number of states. The encoding could be based on a table, a set of rules, for example expressed as example code indexing each possible state, or a formula.

[0071] As an example with T = 4 and max rank 4, 2 bits would be required for T, 2 bits for N, and 2 bits for Nstart, which gives a total of 6 bits if there is no joint encoding. With a joint encoding, 5 bits would be sufficient. Additional compression can be achieved by introducing additional rules. Examples of rules could be to always start even rank on an even port, or to pack the highest ranks on the lowest port index.

[0072] In NR, the scheduling DCI indicates one out of two pre-configured (using Radio Resource Control (RRC)) seeds used to generate the DMRS sequence. It is thus possible that two coscheduled UEs do not use the same seed for the DMRS, and in this case, the co-scheduled UE may not be able to coherently detect the channel of the interferer. However, it can still be useful for the UE to know that a certain antenna port is used by another UE; for example, it can use a noncoherent estimation of the interference power to enhance the reception.

[0073] Hence, in a further embodiment, additional information is signaled from the network to the UE (e.g., using DCI signaling) where this additional signaling informs the UE of whether the DMRS sequence of co-scheduled UEs can be assumed to be the same as the DMRS sequence of the scheduled PDSCH DMRS, or a different sequence. For example, one bit in scheduling DCI can be used for this indication.

[0074] There is a special case for which further attention and special handling may be desired. More specifically, there is a case in NR where co-scheduled UEs use different Code Division Multiplexing (CDM) groups. This has a slight advantage of better channel estimation in very frequency selective channels since Frequency Domain Orthogonal Cover code (FD-OCC) despreading is not needed to separate ports between UEs.

[0075] For example, UE#1 uses port 0 in CDM group 0 and UE#2 uses port 2 in CDM group 1. In this special case, if the NR or 6thGeneration (6G) specifications support it, the co-scheduled ports are not consecutive and some special rule needs to be developed.

[0076] • For UE#2 in this example, the port allocation of co-scheduled UEs can be known without any additional rules, in the case T=2 and UE is scheduled using port #2 since the only possible port used for the other UE is port 0.

[0077] • For UE#1 on the other hand, if T=2 and UE#1 is scheduled port 0, the UE cannot know that port #2 is used for the other UE since the fundamental rule in the present disclosure is that port #1 should have been used for UE#2.

[0078] One way to resolve this is to let the UE#1 decode both hypotheses, that port 1 and that port 2 is used. Due to the embodiments of the present disclosure, the UE knows that one of these two ports must be used, hence, the detection problem is easier and more robust compared to the original detection problem where the UE has no idea on the value T, i.e. how many DMRS ports are actually used. Figure 3 illustrates the operation of a UE 300 and a network node 302 (e.g., a Radio Access Network (RAN) node such as, e.g., a base station (e.g., a gNB) or a network node that performs part of the functionality of a base station (e.g., a gNB -Distributed Unit (DU) or gNB-Central Unit (CU)), in accordance with at least some of the embodiments described above. Note that optional actions are represented in Figure 3 by dashed lines / boxes. Further, while the actions in Figure 3 are shown in the figure as being in a particular order, the actions can be performed in any order and some of the actions may be performed partially or completely in parallel, unless otherwise explicitly stated or required. It should also be noted that while not all of the details from the description above are repeated here with respect to Figure 3, it is to be understood that the details given above are equally applicable to the corresponding actions of Figure 3.

[0079] As illustrated, the UE 300 receives, from the network node 302, DCI scheduling a DL channel transmission (e.g., a PDSCH transmission) to the UE 300 (action 304). The rank of the DL channel transmission, and thus the number of DMRS ports allocated for the DL channel transmission, is denoted herein as N, where N is an integer value greater than or equal to 1 and less than or equal to a predefined maximum rank. The UE 300 also receives, from the network node 302, an indication that indicates either: (a) a total number (T) of allocated DMRS ports for co-scheduled UEs (i.e., for the scheduled downlink channel transmission to the UE and one or more additional scheduled downlink transmissions to one or more co-scheduled UEs, if any) or (b) a number (Y) of DMRS ports that can be used (i.e., available) for inter-cell interference estimation (action 306). In one example embodiment, the indication of step 306 is included in the DCI of step 304. Optionally, in some embodiments, the UE 300 may also receive, from the network node 302 (e.g., in the DCI of step 304), another indication that indicates whether a DMRS sequence used for the DMRS port(s) allocated for the scheduled DL channel transmission to the UE 300 is the same as that used for the DMRS ports allocated for the one or more additional scheduled downlink channel transmissions for the one or more co-scheduled UEs (action 308).

[0080] The UE 300 determines, based on the received indication, a set of DMRS ports, other than the DMRS ports allocated for the scheduled downlink transmission to the UE, that can be used by (i.e., available to) the UE for intra-cell (e.g., MU-MIMO) interference estimation (action 310). In one embodiment, the received indication indicates the total number (T) of allocated DMRS ports for co-scheduled UEs. Further, in one embodiment, there are M available DMRS ports indexed as DMRS ports X to X+M-l (e.g., X=0), and the allocated DMRS ports for co-scheduled UEs are DMRS ports X to X+T-L Further, in one embodiment, the determined set of DMRS ports that can be used by the UE for intra-cell interference estimation consists of T-N DMRS ports from among DMRS ports X to X+T-l other than the N DMRS ports allocated for the scheduled downlink channel transmission to the UE. In one embodiment, the UE 300 may also determine (e.g., in action 314) that DMRS ports X+T to X+M-l can be used by the UE for inter-cell interference estimation.

[0081] In another embodiment, the received indication of action 306 indicates the number (Y) of DMRS ports to be used for inter-cell interference estimation. Further, in one embodiment, there are M available DMRS ports indexed as DMRS ports X to X+M-l (e.g., X=0), and the allocated DMRS ports for co-scheduled UEs are DMRS ports X to X+M-Y-L Still further, in one embodiment, the determined set of DMRS ports that can be used by the UE for intra-cell interference estimation consists of M-Y-N DMRS ports from among DMRS ports X to X+M-Y-l other than the N DMRS ports allocated for the scheduled DL channel transmission to the UE 300. In one embodiment, the UE 300 may also determine (e.g., in action 314) that DMRS ports X+M- Y to X+M-l can be used by the UE 300 for inter-cell interference estimation.

[0082] In one embodiment, the indication of action 306, an indication of the value of N, and an indication of a first DMRS port allocated for the scheduled downlink channel transmission to the UE are jointly encoded.

[0083] In accordance with embodiments of the present disclosure, the determining of action 310 is performed without the need for blind DMRS decoding.

[0084] The UE 300 perform intra-cell (e.g., MU-MIMO) interference estimation using at least a subset of the set of DMRS ports determined in action 310 (action 312).

[0085] The UE 300 may also determine, based on the received indication of action 306, another set of DMRS ports (e.g., the remaining DMRS ports other than those used for the scheduled DL channel transmissions to the UE and the co-scheduled UEs) that can be used by the UE 300 for inter-cell interference estimation (action 314) and may perform inter-cell interference estimation using at least a subset of this other set of DMRS ports (action 316).

[0086] Note that, as discussed above, scheduling of the DL channel transmissions to the UE 300 and the co-scheduled UEs is performed by a scheduler (e.g., a scheduler of the network node 302) based on a scheduling restriction (known by the network node 302 and the UE 300) that the DMRS port numbers of the DMRS ports allocated for the scheduled DL channel transmissions to the UE and the co-scheduled UEs are consecutive integer values (i.e., consecutive DMRS port numbers) and that a lowest numbered DMRS pot is always used, as described above.

[0087] Figure 4 shows an example of a communication system 400 in accordance with some embodiments. The UE 300 may, for example, be one of the UEs 412 of Figure 4. Likewise, the network node 302 may be, for example, one of the network nodes 410 of Figure 4. In the example, the communication system 400 includes a telecommunication network 402 that includes an access network 404, such as a Radio Access Network (RAN), and a core network 406, which includes one or more core network nodes 408. The access network 404 includes one or more access network nodes, such as network nodes 410A and 410B (one or more of which may be generally referred to as network nodes 410), or any other similar Third Generation Partnership Project (3GPP) access nodes or non-3GPP Access Points (APs). Moreover, as will be appreciated by those of skill in the art, a network node is not necessarily limited to an implementation in which a radio portion and a baseband portion are supplied and integrated by a single vendor. Thus, it will be understood that network nodes include disaggregated implementations or portions thereof. For example, in some embodiments, the telecommunication network 402 includes one or more Open-RAN (ORAN) network nodes. An ORAN network node is a node in the telecommunication network 402 that supports an ORAN specification (e.g., a specification published by the O-RAN Alliance, or any similar organization) and may operate alone or together with other nodes to implement one or more functionalities of any node in the telecommunication network 402, including one or more network nodes 410 and / or core network nodes 408.

[0088] Examples of an ORAN network node include an Open Radio Unit (O-RU), an Open Distributed Unit (O-DU), an Open Central Unit (O-CU), including an O-CU Control Plane (O- CU-CP) or an O-CU User Plane (O-CU-UP), a RAN intelligent controller (near-real time or non- real time) hosting software or software plug-ins, such as a near-real time control application (e.g., xApp) or a non-real time control application (e.g., rApp), or any combination thereof (the adjective “open” designating support of an ORAN specification). The network node may support a specification by, for example, supporting an interface defined by the ORAN specification, such as an Al, Fl, Wl, El, E2, X2, Xn interface, an open fronthaul user plane interface, or an open fronthaul management plane interface. Moreover, an ORAN access node may be a logical node in a physical node. Furthermore, an ORAN network node may be implemented in a virtualization environment (described further below) in which one or more network functions are virtualized. For example, the virtualization environment may include an O-Cloud computing platform orchestrated by a Service Management and Orchestration Framework via an O-2 interface defined by the O-RAN Alliance or comparable technologies. The network nodes 410 facilitate direct or indirect connection of User Equipment (UE), such as by connecting UEs 412A, 412B, 412C, and 412D (one or more of which may be generally referred to as UEs 412) to the core network 406 over one or more wireless connections.

[0089] Example wireless communications over a wireless connection include transmitting and / or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and / or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. Moreover, in different embodiments, the communication system 400 may include any number of wired or wireless networks, network nodes, UEs, and / or any other components or systems that may facilitate or participate in the communication of data and / or signals whether via wired or wireless connections. The communication system 400 may include and / or interface with any type of communication, telecommunication, data, cellular, radio network, and / or other similar type of system.

[0090] The UEs 412 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and / or operable to communicate wirelessly with the network nodes 410 and other communication devices. Similarly, the network nodes 410 are arranged, capable, configured, and / or operable to communicate directly or indirectly with the UEs 412 and / or with other network nodes or equipment in the telecommunication network 402 to enable and / or provide network access, such as wireless network access, and / or to perform other functions, such as administration in the telecommunication network 402.

[0091] In the depicted example, the core network 406 connects the network nodes 410 to one or more hosts, such as host 416. These connections may be direct or indirect via one or more intermediary networks or devices. In other examples, network nodes may be directly coupled to hosts. The core network 406 includes one more core network nodes (e.g., core network node 408) that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and / or hosts, such that the descriptions thereof are generally applicable to the corresponding components of the core network node 408. Example core network nodes include functions of one or more of a Mobile Switching Center (MSC), Mobility Management Entity (MME), Home Subscriber Server (HSS), Access and Mobility Management Function (AMF), Session Management Function (SMF), Authentication Server Function (AUSF), Subscription Identifier De-Concealing Function (SIDF), Unified Data Management (UDM), Security Edge Protection Proxy (SEPP), Network Exposure Function (NEF), and / or a User Plane Function (UPF).

[0092] The host 416 may be under the ownership or control of a service provider other than an operator or provider of the access network 404 and / or the telecommunication network 402, and may be operated by the service provider or on behalf of the service provider. The host 416 may host a variety of applications to provide one or more service. Examples of such applications include live and pre-recorded audio / video content, data collection services such as retrieving and compiling data on various ambient conditions detected by a plurality of UEs, analytics functionality, social media, functions for controlling or otherwise interacting with remote devices, functions for an alarm and surveillance center, or any other such function performed by a server.

[0093] As a whole, the communication system 400 of Figure 4 enables connectivity between the UEs, network nodes, and hosts. In that sense, the communication system 400 may be configured to operate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Long Term Evolution (LTE), and / or other suitable Second, Third, Fourth, or Fifth Generation (2G, 3G, 4G, or 5G) standards, or any applicable future generation standard (e.g., Sixth Generation (6G)); Wireless Local Area Network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (WiFi); and / or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, LiFi, and / or any Low Power Wide Area Network (LPWAN) standards such as LoRa and Sigfox.

[0094] In some examples, the telecommunication network 402 is a cellular network that implements 3 GPP standardized features. Accordingly, the telecommunication network 402 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network 402. For example, the telecommunication network 402 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing enhanced Mobile Broadband (eMBB) services to other UEs, and / or massive Machine Type Communication (mMTC) / massive Internet of Things (loT) services to yet further UEs.

[0095] In some examples, the UEs 412 are configured to transmit and / or receive information without direct human interaction. For instance, a UE may be designed to transmit information to the access network 404 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network 404. Additionally, a UE may be configured for operating in single- or multi-Radio Access Technology (RAT) or multi -standard mode. For example, a UE may operate with any one or combination of WiFi, New Radio (NR), and LTE, i.e. being configured for Multi-Radio Dual Connectivity (MR-DC), such as Evolved UMTS Terrestrial RAN (E-UTRAN) NR - Dual Connectivity (EN-DC).

[0096] In the example, a hub 414 communicates with the access network 404 to facilitate indirect communication between one or more UEs (e.g., UE 412C and / or 412D) and network nodes (e.g., network node 410B). In some examples, the hub 414 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, the hub 414 may be a broadband router enabling access to the core network 406 for the UEs. As another example, the hub 414 may be a controller that sends commands or instructions to one or more actuators in the UEs. Commands or instructions may be received from the UEs, network nodes 410, or by executable code, script, process, or other instructions in the hub 414. As another example, the hub 414 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data. As another example, the hub 414 may be a content source. For example, for a UE that is a Virtual Reality (VR) headset, display, loudspeaker or other media delivery device, the hub 414 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which the hub 414 then provides to the UE either directly, after performing local processing, and / or after adding additional local content. In still another example, the hub 414 acts as a proxy server or orchestrator for the UEs, in particular if one or more of the UEs are low energy loT devices.

[0097] The hub 414 may have a constant / persistent or intermittent connection to the network node 410B. The hub 414 may also allow for a different communication scheme and / or schedule between the hub 414 and UEs (e.g., UE 412C and / or 412D), and between the hub 414 and the core network 406. In other examples, the hub 414 is connected to the core network 406 and / or one or more UEs via a wired connection. Moreover, the hub 414 may be configured to connect to a Machine-to-Machine (M2M) service provider over the access network 404 and / or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with the network nodes 410 while still connected via the hub 414 via a wired or wireless connection. In some embodiments, the hub 414 may be a dedicated hub - that is, a hub whose primary function is to route communications to / from the UEs from / to the network node 410B. In other embodiments, the hub 414 may be a non-dedicated hub - that is, a device which is capable of operating to route communications between the UEs and the network node 410B, but which is additionally capable of operating as a communication start and / or end point for certain data channels.

[0098] Figure 5 shows a UE 500 in accordance with some embodiments. As used herein, a UE refers to a device capable, configured, arranged, and / or operable to communicate wirelessly with network nodes and / or other UEs. Examples of a UE include, but are not limited to, a smart phone, mobile phone, cell phone, Voice over Internet Protocol (VoIP) phone, wireless local loop phone, desktop computer, Personal Digital Assistant (PDA), wireless camera, gaming console or device, music storage device, playback appliance, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, Laptop Embedded Equipment (LEE), Laptop Mounted Equipment (LME), smart device, wireless Customer Premise Equipment (CPE), vehicle, vehicle-mounted or vehicle embedded / integrated wireless device, etc. Other examples include any UE identified by the 3 GPP, including a Narrowband Internet of Things (NB-IoT) UE, a Machine Type Communication (MTC) UE, and / or an enhanced MTC (eMTC) UE.

[0099] A UE may support Device-to-Device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, Dedicated Short-Range Communication (DSRC), Vehicle-to-Vehicle (V2V), Vehicle-to-Infrastructure (V2I), or Vehicle-to-Everything (V2X). In other examples, a UE may not necessarily have a user in the sense of a human user who owns and / or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or which may not initially, be associated with a specific human user (e.g., a smart sprinkler controller). Alternatively, a UE may represent a device that is not intended for sale to, or operation by, an end user but which may be associated with or operated for the benefit of a user (e.g., a smart power meter).

[0100] The UE 500 includes processing circuitry 502 that is operatively coupled via a bus 504 to an input / output interface 506, a power source 508, memory 510, a communication interface 512, and / or any other component, or any combination thereof. Certain UEs may utilize all or a subset of the components shown in Figure 5. The level of integration between the components may vary from one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.

[0101] The processing circuitry 502 is configured to process instructions and data and may be configured to implement any sequential state machine operative to execute instructions stored as machine-readable computer programs in the memory 510. The processing circuitry 502 may be implemented as one or more hardware-implemented state machines (e.g., in discrete logic, Field Programmable Gate Arrays (FPGAs), Application Specific Integrated Circuits (ASICs), etc.); programmable logic together with appropriate firmware; one or more stored computer programs, general purpose processors, such as a microprocessor or Digital Signal Processor (DSP), together with appropriate software; or any combination of the above. For example, the processing circuitry 502 may include multiple Central Processing Units (CPUs).

[0102] In the example, the input / output interface 506 may be configured to provide an interface or interfaces to an input device, output device, or one or more input and / or output devices. Examples of an output device include a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. An input device may allow a user to capture information into the UE 500. Examples of an input device include a touch-sensitive or presence-sensitive display, a camera (e.g., a digital camera, a digital video camera, a web camera, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like. The presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. A sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, etc., or any combination thereof. An output device may use the same type of interface port as an input device. For example, a Universal Serial Bus (USB) port may be used to provide an input device and an output device.

[0103] In some embodiments, the power source 508 is structured as a battery or battery pack. Other types of power sources, such as an external power source (e.g., an electricity outlet), photovoltaic device, or power cell, may be used. The power source 508 may further include power circuitry for delivering power from the power source 508 itself, and / or an external power source, to the various parts of the UE 500 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging of the power source 508. Power circuitry may perform any formatting, converting, or other modification to the power from the power source 508 to make the power suitable for the respective components of the UE 500 to which power is supplied.

[0104] The memory 510 may be or be configured to include memory such as Random Access Memory (RAM), Read Only Memory (ROM), Programmable ROM (PROM), Erasable PROM (EPROM), Electrically EPROM (EEPROM), magnetic disks, optical disks, hard disks, removable cartridges, flash drives, and so forth. In one example, the memory 510 includes one or more application programs 514, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 516. The memory 510 may store, for use by the UE 500, any of a variety of various operating systems or combinations of operating systems.

[0105] The memory 510 may be configured to include a number of physical drive units, such as Redundant Array of Independent Disks (RAID), flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, High Density Digital Versatile Disc (HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, Holographic Digital Data Storage (HDDS) optical disc drive, external mini Dual In-line Memory Module (DIMM), Synchronous Dynamic RAM (SDRAM), external micro-DIMM SDRAM, smartcard memory such as a tamper resistant module in the form of a Universal Integrated Circuit Card (UICC) including one or more Subscriber Identity Modules (SIMs), such as a Universal SIM (USIM) and / or Internet Protocol Multimedia Services Identity Module (ISIM), other memory, or any combination thereof. The UICC may for example be an embedded UICC (eUICC), integrated UICC (iUICC) or a removable UICC commonly known as a ‘SIM card.’ The memory 510 may allow the UE 500 to access instructions, application programs, and the like stored on transitory or non-transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system, may be tangibly embodied as or in the memory 510, which may be or comprise a device-readable storage medium.

[0106] The processing circuitry 502 may be configured to communicate with an access network or other network using the communication interface 512. The communication interface 512 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna 522. The communication interface 512 may include one or more transceivers used to communicate, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g., another UE or a network node in an access network). Each transceiver may include a transmitter 518 and / or a receiver 520 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, the transmitter 518 and receiver 520 may be coupled to one or more antennas (e.g., the antenna 522) and may share circuit components, software, or firmware, or alternatively be implemented separately.

[0107] In the illustrated embodiment, communication functions of the communication interface 512 may include cellular communication, WiFi communication, LPWAN communication, data communication, voice communication, multimedia communication, short-range communications such as Bluetooth, NFC, location-based communication such as the use of the Global Positioning System (GPS) to determine a location, another like communication function, or any combination thereof. Communications may be implemented according to one or more communication protocols and / or standards, such as IEEE 802.11, Code Division Multiplexing Access (CDMA), Wideband CDMA (WCDMA), GSM, LTE, NR, UMTS, WiMax, Ethernet, Transmission Control Protocol / Internet Protocol (TCP / IP), Synchronous Optical Networking (SONET), Asynchronous Transfer Mode (ATM), Quick User Datagram Protocol Internet Connection (QUIC), Hypertext Transfer Protocol (HTTP), and so forth.

[0108] Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface 512, via a wireless connection to a network node. Data captured by sensors of a UE can be communicated through a wireless connection to a network node via another UE. The output may be periodic (e.g., once every 15 minutes if it reports the sensed temperature), random (e.g., to even out the load from reporting from several sensors), in response to a triggering event (e.g., when moisture is detected, an alert is sent), in response to a request (e.g., a user initiated request), or a continuous stream (e.g., a live video feed of a patient).

[0109] As another example, a UE comprises an actuator, a motor, or a switch related to a communication interface configured to receive wireless input from a network node via a wireless connection. In response to the received wireless input the states of the actuator, the motor, or the switch may change. For example, the UE may comprise a motor that adjusts the control surfaces or rotors of a drone in flight according to the received input or to a robotic arm performing a medical procedure according to the received input.

[0110] A UE, when in the form of an loT device, may be a device for use in one or more application domains, these domains comprising, but not limited to, city wearable technology, extended industrial application, and healthcare. Non-limiting examples of such an loT device are a device which is or which is embedded in: a connected refrigerator or freezer, a television, a connected lighting device, an electricity meter, a robot vacuum cleaner, a voice controlled smart speaker, a home security camera, a motion detector, a thermostat, a smoke detector, a door / window sensor, a flood / moisture sensor, an electrical door lock, a connected doorbell, an air conditioning system like a heat pump, an autonomous vehicle, a surveillance system, a weather monitoring device, a vehicle parking monitoring device, an electric vehicle charging station, a smart watch, a fitness tracker, a head-mounted display for Augmented Reality (AR) or VR, a wearable for tactile augmentation or sensory enhancement, a water sprinkler, an animal- or item-tracking device, a sensor for monitoring a plant or animal, an industrial robot, an Unmanned Aerial Vehicle (UAV), and any kind of medical device, like a heart rate monitor or a remote controlled surgical robot. A UE in the form of an loT device comprises circuitry and / or software in dependence of the intended application of the loT device in addition to other components as described in relation to the UE 500 shown in Figure 5.

[0111] As yet another specific example, in an loT scenario, a UE may represent a machine or other device that performs monitoring and / or measurements and transmits the results of such monitoring and / or measurements to another UE and / or a network node. The UE may in this case be an M2M device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the UE may implement the 3 GPP NB-IoT standard. In other scenarios, a UE may represent a vehicle, such as a car, a bus, a truck, a ship, an airplane, or other equipment that is capable of monitoring and / or reporting on its operational status or other functions associated with its operation.

[0112] In practice, any number of UEs may be used together with respect to a single use case. For example, a first UE might be or be integrated in a drone and provide the drone’s speed information (obtained through a speed sensor) to a second UE that is a remote controller operating the drone. When the user makes changes from the remote controller, the first UE may adjust the throttle on the drone (e.g., by controlling an actuator) to increase or decrease the drone’s speed. The first and / or the second UE can also include more than one of the functionalities described above. For example, a UE might comprise the sensor and the actuator and handle communication of data for both the speed sensor and the actuators.

[0113] Figure 6 shows a network node 600 in accordance with some embodiments. As used herein, network node refers to equipment capable, configured, arranged, and / or operable to communicate directly or indirectly with a UE and / or with other network nodes or equipment in a telecommunication network. Examples of network nodes include, but are not limited to, APs (e.g., radio APs), Base Stations (BSs) (e.g., radio BSs, Node Bs, evolved Node Bs (eNBs), NR Node Bs (gNBs)), and O-RAN nodes or components of an O-RAN node (e.g., O-RU, O-DU, O-CU).

[0114] Base stations may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and so, depending on the provided amount of coverage, may be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units, distributed units (e.g., in an O-RAN access node), and / or Remote Radio Units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such RRUs may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a Distributed Antenna System (DAS).

[0115] Other examples of network nodes include multiple Transmission Point (multi-TRP) 5G access nodes, Multi -Standard Radio (MSR) equipment such as MSR BSs, network controllers such as Radio Network Controllers (RNCs) or BS Controllers (BSCs), Base Transceiver Stations (BTSs), transmission points, transmission nodes, Multi-Cell / Multicast Coordination Entities (MCEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g., Evolved Serving Mobile Location Centers (E-SMLCs)), and / or Minimization of Drive Tests (MDTs).

[0116] The network node 600 includes processing circuitry 602, memory 604, a communication interface 606, and a power source 608. The network node 600 may be composed of multiple physically separate components (e.g., a NodeB component and an RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which the network node 600 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NodeBs. In such a scenario, each unique NodeB and RNC pair may in some instances be considered a single separate network node. In some embodiments, the network node 600 may be configured to support multiple RATs. In such embodiments, some components may be duplicated (e.g., separate memory 604 for different RATs) and some components may be reused (e.g., a same antenna 610 may be shared by different RATs). The network node 600 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 600, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, Long Range Wide Area Network (LoRaWAN), Radio Frequency Identification (RFID), or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within the network node 600.

[0117] The processing circuitry 602 may comprise a combination of one or more of a microprocessor, controller, microcontroller, CPU, DSP, ASIC, FPGA, or any other suitable computing device, resource, or combination of hardware, software, and / or encoded logic operable to provide, either alone or in conjunction with other network node 600 components, such as the memory 604, to provide network node 600 functionality.

[0118] In some embodiments, the processing circuitry 602 includes a System on a Chip (SOC). In some embodiments, the processing circuitry 602 includes one or more of Radio Frequency (RF) transceiver circuitry 612 and baseband processing circuitry 614. In some embodiments, the RF transceiver circuitry 612 and the baseband processing circuitry 614 may be on separate chips (or sets of chips), boards, or units, such as radio units and digital units. In alternative embodiments, part or all of the RF transceiver circuitry 612 and the baseband processing circuitry 614 may be on the same chip or set of chips, boards, or units.

[0119] The memory 604 may comprise any form of volatile or non-volatile computer-readable memory including, without limitation, persistent storage, solid state memory, remotely mounted memory, magnetic media, optical media, RAM, ROM, mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD), or a Digital Video Disk (DVD)), and / or any other volatile or non-volatile, non-transitory device-readable, and / or computer-executable memory devices that store information, data, and / or instructions that may be used by the processing circuitry 602. The memory 604 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and / or other instructions capable of being executed by the processing circuitry 602 and utilized by the network node 600. The memory 604 may be used to store any calculations made by the processing circuitry 602 and / or any data received via the communication interface 606. In some embodiments, the processing circuitry 602 and the memory 604 are integrated.

[0120] The communication interface 606 is used in wired or wireless communication of signaling and / or data between a network node, access network, and / or UE. As illustrated, the communication interface 606 comprises port(s) / terminal(s) 616 to send and receive data, for example to and from a network over a wired connection. The communication interface 606 also includes radio front-end circuitry 618 that may be coupled to, or in certain embodiments a part of, the antenna 610. The radio front-end circuitry 618 comprises filters 620 and amplifiers 622. The radio front-end circuitry 618 may be connected to the antenna 610 and the processing circuitry 602. The radio front-end circuitry 618 may be configured to condition signals communicated between the antenna 610 and the processing circuitry 602. The radio front-end circuitry 618 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. The radio front-end circuitry 618 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of the filters 620 and / or the amplifiers 622. The radio signal may then be transmitted via the antenna 610. Similarly, when receiving data, the antenna 610 may collect radio signals which are then converted into digital data by the radio front-end circuitry 618. The digital data may be passed to the processing circuitry 602. In other embodiments, the communication interface 606 may comprise different components and / or different combinations of components.

[0121] In certain alternative embodiments, the network node 600 does not include separate radio front-end circuitry 618; instead, the processing circuitry 602 includes radio front-end circuitry and is connected to the antenna 610. Similarly, in some embodiments, all or some of the RF transceiver circuitry 612 is part of the communication interface 606. In still other embodiments, the communication interface 606 includes the one or more ports or terminals 616, the radio front-end circuitry 618, and the RF transceiver circuitry 612 as part of a radio unit (not shown), and the communication interface 606 communicates with the baseband processing circuitry 614, which is part of a digital unit (not shown).

[0122] The antenna 610 may include one or more antennas, or antenna arrays, configured to send and / or receive wireless signals. The antenna 610 may be coupled to the radio front-end circuitry 618 and may be any type of antenna capable of transmitting and receiving data and / or signals wirelessly. In certain embodiments, the antenna 610 is separate from the network node 600 and connectable to the network node 600 through an interface or port.

[0123] The antenna 610, the communication interface 606, and / or the processing circuitry 602 may be configured to perform any receiving operations and / or certain obtaining operations described herein as being performed by the network node 600. Any information, data, and / or signals may be received from a UE, another network node, and / or any other network equipment. Similarly, the antenna 610, the communication interface 606, and / or the processing circuitry 602 may be configured to perform any transmitting operations described herein as being performed by the network node 600. Any information, data, and / or signals may be transmitted to a UE, another network node, and / or any other network equipment.

[0124] The power source 608 provides power to the various components of the network node 600 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). The power source 608 may further comprise, or be coupled to, power management circuitry to supply the components of the network node 600 with power for performing the functionality described herein. For example, the network node 600 may be connectable to an external power source (e.g., the power grid or an electricity outlet) via input circuitry or an interface such as an electrical cable, whereby the external power source supplies power to power circuitry of the power source 608. As a further example, the power source 608 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail.

[0125] Embodiments of the network node 600 may include additional components beyond those shown in Figure 6 for providing certain aspects of the network node’s functionality, including any of the functionality described herein and / or any functionality necessary to support the subject matter described herein. For example, the network node 600 may include user interface equipment to allow input of information into the network node 600 and to allow output of information from the network node 600. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for the network node 600. In some embodiments providing a core network node, such as core network node 108 of FIG. 4, some components, such as the radio frontend circuitry 618 and the RF transceiver circuitry 612 may be omitted.

[0126] Figure 7 is a block diagram illustrating a virtualization environment 700 in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices, and networking resources. As used herein, virtualization can be applied to any device described herein, or components thereof, and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components. Some or all of the functions described herein may be implemented as virtual components executed by one or more Virtual Machines (VMs) implemented in one or more virtualization environments 700 hosted by one or more of hardware nodes, such as a hardware computing device that operates as a network node, a UE, a core network node, or a host. Further, in embodiments in which the virtual node does not require radio connectivity (e.g., a core network node or host), then the node may be entirely virtualized. In some embodiments, the virtualization environment 700 includes components defined by the O-RAN Alliance, such as an O-Cloud environment orchestrated by a Service Management and Orchestration Framework via an 0-2 interface. Virtualization may facilitate distributed implementations of a network node, a UE, a core network node, or a host.

[0127] Applications 702 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment 700 to implement some of the features, functions, and / or benefits of some of the embodiments disclosed herein.

[0128] Hardware 704 includes processing circuitry, memory that stores software and / or instructions executable by hardware processing circuitry, and / or other hardware devices as described herein, such as a network interface, an input / output interface, and so forth. Software may be executed by the processing circuitry to instantiate one or more virtualization layers 706 (also referred to as hypervisors or Virtual Machine Monitors (VMMs)), provide VMs 708A and 708B (one or more of which may be generally referred to as VMs 708), and / or perform any of the functions, features, and / or benefits described in relation with some embodiments described herein. The virtualization layer 706 may present a virtual operating platform that appears like networking hardware to the VMs 708.

[0129] The VMs 708 comprise virtual processing, virtual memory, virtual networking, or interface and virtual storage, and may be run by a corresponding virtualization layer 706. Different embodiments of the instance of a virtual appliance 702 may be implemented on one or more of VMs 708, and the implementations may be made in different ways. Virtualization of the hardware is in some contexts referred to as Network Function Virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers and customer premise equipment.

[0130] In the context of NFV, a VM 708 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, non-virtualized machine. Each of the VMs 708, and that part of the hardware 704 that executes that VM, be it hardware dedicated to that VM and / or hardware shared by that VM with others of the VMs, forms separate virtual network elements. Still in the context of NFV, a virtual network function is responsible for handling specific network functions that run in one or more VMs 708 on top of the hardware 704 and corresponds to the application 702.

[0131] The hardware 704 may be implemented in a standalone network node with generic or specific components. The hardware 704 may implement some functions via virtualization. Alternatively, the hardware 704 may be part of a larger cluster of hardware (e.g., such as in a data center or CPE) where many hardware nodes work together and are managed via management and orchestration 710, which, among others, oversees lifecycle management of the applications 702. In some embodiments, the hardware 704 is coupled to one or more radio units that each include one or more transmitters and one or more receivers that may be coupled to one or more antennas. Radio units may communicate directly with other hardware nodes via one or more appropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station. In some embodiments, some signaling can be provided with the use of a control system 712 which may alternatively be used for communication between hardware nodes and radio units.

[0132] Although the computing devices described herein (e.g., UEs, network nodes) may include the illustrated combination of hardware components, other embodiments may comprise computing devices with different combinations of components. It is to be understood that these computing devices may comprise any suitable combination of hardware and / or software needed to perform the tasks, features, functions, and methods disclosed herein. Determining, calculating, obtaining, or similar operations described herein may be performed by processing circuitry, which may process information by, for example, converting the obtained information into other information, comparing the obtained information or converted information to information stored in the network node, and / or performing one or more operations based on the obtained information or converted information, and as a result of said processing making a determination. Moreover, while components are depicted as single boxes located within a larger box, or nested within multiple boxes, in practice, computing devices may comprise multiple different physical components that make up a single illustrated component, and functionality may be partitioned between separate components. For example, a communication interface may be configured to include any of the components described herein, and / or the functionality of the components may be partitioned between the processing circuitry and the communication interface. In another example, non- computationally intensive functions of any of such components may be implemented in software or firmware and computationally intensive functions may be implemented in hardware.

[0133] In certain embodiments, some or all of the functionality described herein may be provided by processing circuitry executing instructions stored on in memory, which in certain embodiments may be a computer program product in the form of a non-transitory computer-readable storage medium. In alternative embodiments, some or all of the functionality may be provided by the processing circuitry without executing instructions stored on a separate or discrete device-readable storage medium, such as in a hard-wired manner. In any of those particular embodiments, whether executing instructions stored on a non-transitory computer-readable storage medium or not, the processing circuitry can be configured to perform the described functionality. The benefits provided by such functionality are not limited to the processing circuitry alone or to other components of the computing device, but are enjoyed by the computing device as a whole, and / or by end users and a wireless network generally.

[0134] Those skilled in the art will recognize improvements and modifications to the embodiments of the present disclosure. All such improvements and modifications are considered within the scope of the concepts disclosed herein.

[0135] Some exemplary embodiments of the present disclosure are as follows:

[0136] Group A Embodiments

[0137] Embodiment 1 : A method performed by a User Equipment, UE, (300) the method comprising:

[0138] • receiving (304), from a network node (302), downlink control information that schedules a downlink channel transmission to the UE, wherein a number (N) of DMRS ports are allocated for the scheduled downlink channel transmission to the UE;

[0139] • receiving (306), from the network node (e.g., in the DCI), an indication that indicates either: o a total number (T) of allocated DMRS ports for co-scheduled UEs (i.e., for the scheduled downlink channel transmission to the UE and one or more additional scheduled downlink transmissions to one or more co-scheduled UEs, if any); or o a number (Y) of DMRS ports that can be used for inter-cell interference estimation; and

[0140] • determining (310), based on the received indication, a set of DMRS ports, other than the DMRS ports allocated for the scheduled downlink transmission to the UE, that can be used by the UE for intra-cell (e.g., MU-MIMO) interference estimation.

[0141] Embodiment 2: The method of embodiment 1, wherein the received indication indicates the total number (T) of allocated DMRS ports for co-scheduled UEs.

[0142] Embodiment 3 : The method of embodiment 2, wherein there are M available DMRS ports indexed as DMRS ports X to X+M-l (e.g., X=0), and the allocated DMRS ports for co-scheduled UEs are DMRS ports X to X+T-l .

[0143] Embodiment 4: The method of embodiment 3, wherein the determined set of DMRS ports that can be used by the UE for intra-cell interference estimation consists of T-N DMRS ports from among DMRS ports X to X+T-l other than the N DMRS ports allocated for the scheduled downlink channel transmission to the UE. Embodiment 5: The method of embodiment 4, further comprising determining (314) that DMRS ports X+T to X+M-l can be used by the UE for inter-cell interference estimation.

[0144] Embodiment 6: The method of embodiment 1, wherein the received indication indicates the number (Y) of DMRS ports to be used for inter-cell interference estimation.

[0145] Embodiment 7: The method of embodiment 6, wherein there are M available DMRS ports indexed as DMRS ports X to X+M-l (e.g., X=0), and the allocated DMRS ports for co-scheduled UEs are DMRS ports X to X+M-Y-l .

[0146] Embodiment 8: The method of embodiment 7, wherein the determined set of DMRS ports that can be used by the UE for intra-cell interference estimation consists of M-Y-N DMRS ports from among DMRS ports X to X+M-Y-l other than the N DMRS ports allocated for the scheduled downlink channel transmission to the UE.

[0147] Embodiment 9: The method of embodiment 8, further comprising determining (314) that DMRS ports X+M-Y to X+M-l can be used by the UE for inter-cell interference estimation.

[0148] Embodiment 10: The method of any of embodiments 1 to 9, wherein the received indication, N, and an indication of a first DMRS port allocated for the scheduled downlink channel transmission to the UE are jointly encoded.

[0149] Embodiment 11 : The method of any of embodiments 1 to 10, further comprising receiving (308), from the network node, additional information that indicates whether a DMRS sequence used for the DMRS port(s) allocated for the scheduled downlink channel transmission to the UE is the same as that used for the DMRS ports allocated for the one or more additional scheduled downlink channel transmissions for the one or more co-scheduled UEs.

[0150] Embodiment 12: The method of any of embodiments 1 to 11, wherein determining (310) the set of DMRS ports, other than the DMRS ports allocated for the scheduled downlink transmission to the UE, that can be used by the UE for intra-cell interference estimation comprises determining (310) the set of DMRS ports, other than the DMRS ports allocated for the scheduled downlink transmission to the UE, that can be used by the UE for intra-cell interference estimation without blind DMRS decoding.

[0151] Embodiment 13: The method of any of embodiments 1 to 12, further comprising performing (312) intra-cell interference estimation using at least a subset of the determined set of DMRS ports.

[0152] Embodiment 14: The method of any of embodiments 1 to 13, wherein the UE assumes that, in the case of MU-MIMO, DMRS ports scheduled for the UE and any co-scheduled UEs are indexed via consecutive DMRS number numbers and that a lowest numbered DMRS port is always used. Group B Embodiments

[0153] Embodiment 15: A method performed by a network node (302), the method comprising:

[0154] • transmitting (304), to a UE (300), downlink control information that schedules a downlink channel transmission to the UE, wherein a number (N) of DMRS ports are allocated for the scheduled downlink channel transmission to the UE;

[0155] • transmitting (306), to the UE (e.g., in the DCI), an indication that indicates either: o a total number (T) of allocated DMRS ports for co-scheduled UEs (i.e., for the scheduled downlink channel transmission to the UE and one or more additional scheduled downlink transmissions to one or more co-scheduled UEs, if any); or o a number (Y) of DMRS ports that can be used for inter-cell interference estimation.

[0156] Embodiment 16: The method of embodiment 15, wherein the transmitted indication indicates the total number (T) of allocated DMRS ports for co-scheduled UEs.

[0157] Embodiment 17: The method of embodiment 16, wherein there are M available DMRS ports indexed as DMRS ports X to X+M-l (e.g., X=0), and the allocated DMRS ports for coscheduled UEs are DMRS ports 0 to T-l.

[0158] Embodiment 18: The method of embodiment 17, wherein a set of DMRS ports that can be used by the UE for intra-cell interference estimation consists of T-N DMRS ports from among DMRS ports X to X+T-l other than the N DMRS ports allocated for the scheduled downlink channel transmission to the UE.

[0159] Embodiment 19: The method of embodiment 18, wherein DMRS ports X+T to X+M-l can be used by the UE for inter-cell interference estimation.

[0160] Embodiment 20: The method of embodiment 15, wherein the transmitted indication indicates the number (Y) of DMRS ports to be used for inter-cell interference estimation.

[0161] Embodiment 21 : The method of embodiment 20, wherein there are M available DMRS ports indexed as DMRS ports X to X+M-l (e.g., X=0), and the allocated DMRS ports for coscheduled UEs are DMRS ports X to X+M-Y-l.

[0162] Embodiment 22: The method of embodiment 21, wherein a set of DMRS ports that can be used by the UE for intra-cell interference estimation consists of M-Y-N DMRS ports from among DMRS ports X to X+M-Y-l other than the N DMRS ports allocated for the scheduled downlink channel transmission to the UE.

[0163] Embodiment 23: The method of embodiment 22, wherein DMRS ports X+M-Y to X+M-l can be used by the UE for inter-cell interference estimation. Embodiment 24: The method of any of embodiments 15 to 23, wherein the transmitted indication, N, and an indication of a first DMRS port allocated for the scheduled downlink channel transmission to the UE are jointly encoded.

[0164] Embodiment 25: The method of any of embodiments 15 to 24, further comprising transmitting (308), to the UE, additional information that indicates whether a DMRS sequence used for the DMRS port(s) allocated for the scheduled downlink channel transmission to the UE as that used for the DMRS ports allocated for the one or more additional scheduled downlink channel transmissions for the one or more co-scheduled UEs.

[0165] Embodiment 26: The method of any of embodiments 15 to 25, wherein the network node performs scheduling of the UE and the one or more co-scheduled UEs based on a scheduling restriction that that, in the case of MU-MIMO, DMRS ports scheduled for the UE and any coscheduled UEs are indexed via consecutive DMRS number numbers and that a lowest numbered DMRS port is always used.

[0166] Group C Embodiments

[0167] Embodiment 27: A user equipment comprising: processing circuitry configured to perform any of the steps of any of the Group A embodiments; and power supply circuitry configured to supply power to the processing circuitry.

[0168] Embodiment 28: A network node comprising: processing circuitry configured to perform any of the steps of any of the Group B embodiments; and power supply circuitry configured to supply power to the processing circuitry.

[0169] Embodiment 29: A user equipment (UE) comprising: an antenna configured to send and receive wireless signals; radio front-end circuitry connected to the antenna and to processing circuitry, and configured to condition signals communicated between the antenna and the processing circuitry; the processing circuitry being configured to perform any of the steps of any of the Group A embodiments; an input interface connected to the processing circuitry and configured to allow input of information into the UE to be processed by the processing circuitry; an output interface connected to the processing circuitry and configured to output information from the UE that has been processed by the processing circuitry; and a battery connected to the processing circuitry and configured to supply power to the UE.

Claims

CLAIMS1. A method performed by a User Equipment, UE, (300) the method comprising:• receiving (304), from a network node (302), downlink control information that schedules a downlink channel transmission to the UE, wherein a number (N>1) of demodulation reference signal, DMRS, ports are allocated for the scheduled downlink channel transmission to the UE;• receiving (306), from the network node, an indication that indicates either: o a total number (T) of allocated DMRS ports for the scheduled downlink channel transmission to the UE and one or more additional scheduled downlink transmissions to one or more other UEs, if any; or o a number (Y) of DMRS ports available for inter-cell interference estimation; and• determining (310), based on the received indication, a set of DMRS ports, other than the DMRS ports allocated for the scheduled downlink transmission to the UE, available to the UE for intra-cell interference estimation.

2. The method of claim 1, wherein the received indication indicates the total number (T) of allocated DMRS ports for the UE and the one or more other UEs.

3. The method of claim 2, wherein there are M available DMRS ports indexed as DMRS ports X to X+M-l where M>T, and the allocated DMRS ports for the UE and the one or more other UEs are DMRS ports X to X+T-l .

4. The method of claim 3, wherein the determined set of DMRS ports available to the UE for intra-cell interference estimation consists of T-N DMRS ports from among DMRS ports X to X+T- 1 other than the N DMRS ports allocated for the scheduled downlink channel transmission to the UE.

5. The method of claim 4, further comprising determining (314) that DMRS ports X+T to X+M-l can be used by the UE for inter-cell interference estimation.

6. The method of claim 1, wherein the received indication indicates the number (Y) of DMRS ports available for inter-cell interference estimation.

7. The method of claim 6, wherein there are M available DMRS ports indexed as DMRS portsX to X+M-l, and the allocated DMRS ports for the UE and the one or more other UEs are DMRS ports X to X+M-Y-l .

8. The method of claim 7, wherein the determined set of DMRS ports available to the UE for intra-cell interference estimation consists of M-Y-N DMRS ports from among DMRS ports X to X+M-Y-l other than the N DMRS ports allocated for the scheduled downlink channel transmission to the UE.

9. The method of claim 8, further comprising determining (314) that DMRS ports X+M-Y to X+M-l can be used by the UE for inter-cell interference estimation.

10. The method of any of claims 1 to 9, wherein the received indication, N, and an indication of a first DMRS port allocated for the scheduled downlink channel transmission to the UE are jointly encoded.

11. The method of any of claims 1 to 10, further comprising receiving (308), from the network node, additional information that indicates whether a DMRS sequence used for the DMRS port(s) allocated for the scheduled downlink channel transmission to the UE is the same as that used for the DMRS ports allocated for the one or more additional scheduled downlink channel transmissions for the one or more other UEs.

12. The method of any of claims 1 to 11, wherein determining (310) the set of DMRS ports, other than the DMRS ports allocated for the scheduled downlink transmission to the UE, available to the UE for intra-cell interference estimation comprises determining (310) the set of DMRS ports, other than the DMRS ports allocated for the scheduled downlink transmission to the UE, available to the UE for intra-cell interference estimation without blind DMRS decoding.

13. The method of any of claims 1 to 12, further comprising performing (312) intra-cell interference estimation using at least a subset of the determined set of DMRS ports.

14. The method of any of claims 1 to 13, wherein the UE assumes that, in the case of MU- MIMO, DMRS ports scheduled for the UE and any other UEs that are also scheduled for downlink transmission are indexed via consecutive DMRS number numbers and that a lowest numbered DMRS port is always used.

15. A User Equipment, UE, (300) configured to :• receive (304), from a network node (302), downlink control information that schedules a downlink channel transmission to the UE, wherein a number (N>1) of demodulation reference signal, DMRS, ports are allocated for the scheduled downlink channel transmission to the UE;• receive (306), from the network node, an indication that indicates either: o a total number (T) of allocated DMRS ports for the scheduled downlink channel transmission to the UE and one or more additional scheduled downlink transmissions to one or more other UEs, if any; or o a number (Y) of DMRS ports available for inter-cell interference estimation; and• determine (310), based on the received indication, a set of DMRS ports, other than the DMRS ports allocated for the scheduled downlink transmission to the UE, available to the UE for intra-cell interference estimation.

16. The UE (300) of claim 15, further configured to perform the method of any of claims 2 to 14.

17. A User Equipment, UE, (300; 500) comprising:• a communication interface (512) comprising a transmitter (518) and a receiver (520); and• processing circuitry (502) associated with the communication interface (512), the processing circuitry (502) configured to cause the UE (300; 500) to: o receive (304), from a network node (302), downlink control information that schedules a downlink channel transmission to the UE, wherein a number (N>1) of demodulation reference signal, DMRS, ports are allocated for the scheduled downlink channel transmission to the UE; o receive (306), from the network node, an indication that indicates either:■ a total number (T) of allocated DMRS ports for the scheduled downlink channel transmission to the UE and one or more additional scheduled downlink transmissions to one or more other UEs, if any; or■ a number (Y) of DMRS ports available for inter-cell interference estimation; and o determine (310), based on the received indication, a set of DMRS ports, other than the DMRS ports allocated for the scheduled downlink transmission to the UE,available to the UE for intra-cell interference estimation.

18. The UE (300; 500) of claim 17, wherein the processing circuitry (502) is further configured to cause the UE (300; 500) to perform the method of any of claims 2 to 14.

19. A method performed by a network node (302), the method comprising:• transmitting (304), to a User Equipment, UE, (300), downlink control information that schedules a downlink channel transmission to the UE, wherein a number (N) of demodulation reference signal, DMRS, ports are allocated for the scheduled downlink channel transmission to the UE;• transmitting (306), to the UE (300), an indication that indicates either: o a total number (T) of allocated DMRS ports for the scheduled downlink channel transmission to the UE (300) and one or more additional scheduled downlink transmissions to one or more other UEs, if any; or o a number (Y) of DMRS ports available for inter-cell interference estimation.

20. The method of claim 19, wherein the transmitted indication indicates the total number (T) of allocated DMRS ports for the UE and the one or more other UEs.

21. The method of claim 20, wherein there are M available DMRS ports indexed as DMRS ports X to X+M-l, and the allocated DMRS ports for the UE and the one or more other UEs are DMRS ports 0 to T-l.

22. The method of claim 21, wherein a set of DMRS ports available to the UE for intra-cell interference estimation consists of T-N DMRS ports from among DMRS ports X to X+T-l other than the N DMRS ports allocated for the scheduled downlink channel transmission to the UE.

23. The method of claim 22, wherein DMRS ports X+T to X+M-l can be used by the UE for inter-cell interference estimation.

24. The method of claim 19, wherein the transmitted indication indicates the number (Y) of DMRS ports to be used for inter-cell interference estimation.

25. The method of claim 24, wherein there are M available DMRS ports indexed as DMRSports X to X+M-l, and the allocated DMRS ports for the UE and the one or more other UEs are DMRS ports X to X+M-Y-l .

26. The method of claim 25, wherein a set of DMRS ports available to the UE for intra-cell interference estimation consists of M-Y-N DMRS ports from among DMRS ports X to X+M-Y-l other than the N DMRS ports allocated for the scheduled downlink channel transmission to the UE.

27. The method of claim 26, wherein DMRS ports X+M-Y to X+M-l can be used by the UE for inter-cell interference estimation.

28. The method of any of claims 19 to 27, wherein the transmitted indication, N, and an indication of a first DMRS port allocated for the scheduled downlink channel transmission to the UE are jointly encoded.

29. The method of any of claims 19 to 28, further comprising transmitting (308), to the UE, additional information that indicates whether a DMRS sequence used for the DMRS port(s) allocated for the scheduled downlink channel transmission to the UE as that used for the DMRS ports allocated for the one or more additional scheduled downlink channel transmissions for the one or more other UEs.

30. The method of any of claims 19 to 29, wherein the network node performs scheduling of the UE and the one or more other UEs based on a scheduling restriction that in the case of Multiuser Multiple Input Multiple Output, MU-MIMO, DMRS ports scheduled for the UE and any other UEs that are also scheduled for downlink transmission are indexed via consecutive DMRS number numbers and that a lowest numbered DMRS port is always used.

31. A network node (302) configured to:• transmit (304), to a User Equipment, UE, (300), downlink control information that schedules a downlink channel transmission to the UE, wherein a number (N) of demodulation reference signal, DMRS, ports are allocated for the scheduled downlink channel transmission to the UE;• transmit (306), to the UE (300), an indication that indicates either: o a total number (T) of allocated DMRS ports for the scheduled downlink channeltransmission to the UE (300) and one or more additional scheduled downlink transmissions to one or more other UEs, if any; or o a number (Y) of DMRS ports available for inter-cell interference estimation.

32. The network node (302) of claim 31, further configured to perform the method of any of claims 20 to 30.

33. A network node (302; 600) comprising processing circuitry (602) configured to cause the network node (302; 600) to:• transmit (304), to a User Equipment, UE, (300), downlink control information that schedules a downlink channel transmission to the UE, wherein a number (N) of demodulation reference signal, DMRS, ports are allocated for the scheduled downlink channel transmission to the UE;• transmit (306), to the UE(300), an indication that indicates either: o a total number (T) of allocated DMRS ports for the scheduled downlink channel transmission to the UE (300) and one or more additional scheduled downlink transmissions to one or more other UEs, if any; or o a number (Y) of DMRS ports available for inter-cell interference estimation.

34. The network node (302; 600) of claim 33, wherein the processing circuitry (602) is further configured to cause the network node (302; 600) to perform the method of any of claims 20 to 30.

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