WO2016164009A1

WO2016164009A1 - Multi-user operation

Info

Publication number: WO2016164009A1
Application number: PCT/US2015/024906
Authority: WO
Inventors: Xiaoyi Wang; Bishwarup Mondal; Eugene Visotsky
Original assignee: Nokia Solutions And Networks Oy
Priority date: 2015-04-08
Filing date: 2015-04-08
Publication date: 2016-10-13

Abstract

Various communication systems may benefit from multiple user (multi-user) operation. For example, configurable multi-user operation for frequency division multiple-input / multiple-output (FD-MIMO) may benefit a long term evolution (LTE) system as well as further developments in fifth generation (5G) systems of the third generation partnership project (3GPP). A method, for example, can include deciding a multi-user dimensioning table for a user equipment on a per-user-equipment basis. The method can also include configuring the decided multi-user dimensioning table to the user equipment.

Description

Multi-user Operation

BACKGROUND:

Field:

[0001] Various communication systems may benefit from multiple user (multi-user) operation. For example, configurable multi-user operation for frequency division multiple-input / multiple-output (FD-MEVIO) may benefit a long term evolution (LTE) system as well as further developments in fifth generation (5G) systems of the third generation partnership project (3GPP).

Description of the Related Art:

[0002] Multi-antenna and MEVIO techniques such as demodulation reference signal (DMRS)-based precoding in elevation domain are considered in 3 GPP. An aspect for consideration is multi-user operation dimensioning when large number of base-station antenna elements are implemented. Considering three-dimensional MEVIO (3D- MEVIO) relies on large number of antenna elements, bigger beamforming gain can normally be obtained. Thus the multi-user (MU)-dimensioning may need to be increased to maximize the system throughput.

[0003] Currently, the MU dimensioning per cell is determined by the indicator bits in the DCI format, namely antenna port(s), scrambling identity and number of layers indication. The example of MU indicator bits in current DCI-2C/2D is as shown in Figure 1.

[0004] Figure 1 illustrates MU indicator bits in current DCI-2C/2D. Essentially, the table in Figure 1 determined that the maximum number of MU layers, with orthogonal DMRS, is 2.

SUMMARY:

[0005] According to certain embodiments, a method can include deciding a multi-user dimensioning table for a user equipment on a per-user-equipment basis. The method can also include configuring the decided multi-user dimensioning table to the user equipment. [0006] In certain embodiments, a method can include receiving, from an access node, a configuration of a multi-user dimensioning table selected from a plurality of multiuser dimensioning tables. The method can also include operating a user equipment based on the received configuration of the multi-user dimensioning table.

[0007] An apparatus, according to certain embodiments, can include at least one processor and at least one memory including computer program code. The at least one memory and the computer program code can be configured to, with the at least one processor, cause the apparatus at least to decide a multi-user dimensioning table for a user equipment on a per-user-equipment basis. The at least one memory and the computer program code can also be configured to, with the at least one processor, cause the apparatus at least to configure the decided multi-user dimensioning table to the user equipment.

[0008] An apparatus, in certain embodiments, can include at least one processor and at least one memory including computer program code. The at least one memory and the computer program code can be configured to, with the at least one processor, cause the apparatus at least to receive, from an access node, a configuration of a multiuser dimensioning table selected from a plurality of multi-user dimensioning tables. The at least one memory and the computer program code can also be configured to, with the at least one processor, cause the apparatus at least to operate a user equipment based on the received configuration of the multi-user dimensioning table.

[0009] According to certain embodiments, an apparatus can include means for deciding a multi-user dimensioning table for a user equipment on a per-user- equipment basis. The apparatus can also include means for configuring the decided multi-user dimensioning table to the user equipment.

[0010] In certain embodiments, an apparatus can include means for receiving, from an access node, a configuration of a multi-user dimensioning table selected from a plurality of multi-user dimensioning tables. The apparatus can also include means for operating a user equipment based on the received configuration of the multi-user dimensioning table.

[0011] A computer program product can, according to certain embodiments, encode instructions for performing any of the above-described methods.

[0012] A non-transitory computer readable medium can, in certain embodiments, be encoded with instructions that, when executed in hardware, perform a process. The process can include any of the above-described methods.

BRIEF DESCRIPTION OF THE DRAWINGS:

[0013] For proper understanding of the invention, reference should be made to the accompanying drawings, wherein:

[0014] Figure 1 illustrates MU indicator bits in current DCI-2C/2D.

[0015] Figure 2 illustrates a configuration method suitable for a multi-user operation according to certain embodiments.

[0016] Figure 3 illustrates a first option for a non-line-of-sight cell center user equipment, according to certain embodiments.

[0017] Figure 4 illustrates a second option for a non-line-of-sight cell center user equipment, according to certain embodiments.

[0018] Figure 5 illustrates an option for a high geometry user equipment, according certain embodiments.

[0019] Figure 6 illustrates an option for a user equipment with two receivers, according to certain embodiments.

[0020] Figure 7 illustrates a system according to certain embodiments. DETAILED DESCRIPTION:

[0021] Some embodiments of the present invention will now be described hereinafter with reference to accompanying drawings. It should be appreciated that the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0022] Certain embodiments relate to design aspects of three-dimensional multiple- input/multiple-output (3D-MIMO) especially in multi-user (MU) operation. Although there are a variety of suggestions for enlarging MU dimensioning, conventional approaches do not address a fundamental issue: each user equipment (UE) may have different radio channel quality, and thus may be suitable for different operation modes.

[0023] There are several examples of different radio channel quality situations. For example, a cell edge UE with low geometry may not be suited to MU operation. For UEs in such a situation, it may be better to reuse an existing MU pairing scheme.

[0024] In another example, a UE with line of sight (LOS) to a base station or other access node may be more suited to rank-1 MU-operation. In such a case, it may be better to focus on rank-1 MU, providing a large number of orthogonal DMRS layers with rank-1 for each user.

[0025] In a third example, a UE with non-line-of-sight (NLOS) to a base station or other access node may be suited to rank-2 MU-operation. In that case, it may be better to focus on rank-2 MU, which may provide more orthogonal DMRS layers with rank-2 for each user.

[0026] Figure 2 illustrates a configuration method suitable for a multi-user operation according to certain embodiments. The method is suitable for 3D- MIMO especially for FD-MIMO. In configuration, an access node may choose to prioritize legacy, SU-MIMO or MU-MIMO operation UE-specifically.

[0027] As shown in Figure 2, at 210 an access node, such as an evolved Node B (eNB) of LTE- Advanced, base station or other suitable apparatus may configure a user equipment (UE) into a transmission mode supporting flexible MU- dimensioning operation. For signaling or other configuration indication purposes, this transmission mode may be named, for example as a transmission mode, TM 12. Another option is a new RRC signaling parameter indicating the flexible mode.

[0028] At 220, the access node may decide a MU dimensioning table for one particular UE, on a UE-specific basis. The decision may be based on a cell load, traffic quality of service (QoS) type, buffer status, UE channel quality indicator (CQI), geometry and/or downlink control channel overhead, etc. Some examples of suitable MU dimensioning tables are put forward below.

[0029] At 230, the access node may configure the decided MU dimensioning table to UE. This configuration may be carried out by using radio resource control (RRC) signaling from the eNB to the UE. The signaling may be identifying one of the candidate tables to be used or individually configuring each entry of the table: For each entry of the MU-dimensioning table, the RRC configuration may include at least one of the following: number of layers, which port to be used for each layer and SCID (scrambling identity SCM (spatial channel model) for DMRS (demodulation reference signal) sequence generation. In one embodiment, an access node sends DCI message including one or more bits indicating which entry in the configured MU-dimensioning table the UE shall use for a PDSCH transmission.

[0030] Thus, in certain embodiments, there can be UE specific MU dimensioning configuration. For example, the bits for Antenna port(s), scrambling identity and number of layers indication in downlink control information (DCI) can be configured through higher layer signaling in a UE specific manner.

[0031] The MU dimensioning or configuration tables presented in the following examples were obtained by simulations. At 220, a node can choose a suitable table from a predetermined set of candidate tables, for example, the following examples. Figure 3 illustrates a first option for a non-line-of-sight cell center user equipment, according to certain embodiments. Figure 4 illustrates a second option for a non-line-of-sight cell center user equipment, according to certain embodiments. Figure 5 illustrates an option for a high geometry user equipment, according certain embodiments. Figure 6 illustrates an option for a user equipment with two receivers, according to certain embodiments.

[0032] More particularly, for example, a NLOS cell center UE can be configured with a MU table according to one of the following two non-limiting options, as illustrated in Figures 3 and 4.

[0033] Figure 3 illustrates a first option for a non-line-of-sight cell center user equipment, according to certain embodiments. As shown in Figure 3, according to a first option, there can be 24 resource elements (REs) DMRS for MU. In this example, there can be from one to eight layers as shown.

[0034] Figure 4 illustrates a second option for a non-line-of-sight cell center user equipment, according to certain embodiments. As shown in Figure 4, according to a second option, there can be 12 REs DMRS for MU. As with the example in Figure 3, there can be from one to eight layers, as shown. However, while the embodiment shown in Figure 3 did not include options for 5 and 6 layers, the embodiment shown in Figure 4 can provide such options.

[0035] Figure 5 illustrates an option for a high geometry user equipment, according certain embodiments. As shown in Figure 5, a NLOS cell center UE, for example a high geometry UE, can be configured with a MU table. As with the example in Figure 4, the example in Figure 5 can provide options for from one to eight layers.

[0036] Figure 6 illustrates an option for a user equipment with two receivers, according to certain embodiments. As shown in Figure 6, a UE with only two receivers (2Rx) may also be configured for MU-MIMO optimized operation. This approach may use 12 DMRS as in release 12 (Rel-12). This option may allow greater flexibility of dynamic single user (SU) and MU operation while sacrificing the ability to transmit 3 or more layers. Unlike the other options, in this option there may be only up to two layers.

[0037] As can be seen from a comparison of Figures 3-6, there can be various similarities and differences amongst the various tables. For example, in each case, one codeword, namely codeword 0 enabled and codeword 1 disabled, with value 0 can correspond to one layer, antenna port 7, and scrambling identity nscm ⁼ 0. For convenience of reference the table of Figure 3 can be referred to as option A, the table of Figure 4 can be referred to as option B, the table of Figure 5 can be referred to as option C, and the table of Figure 6 can be referred to as option D.

[0038] In the case of one codeword, value 1 can correspond to 1 layer, antenna port 8, and scrambling identity n_SciD = 0 for options A and B, whereas one codeword, value 1 can correspond to 1 layer, antenna port 7, and scrambling identity n_SciD ⁼ 1 for options C and D.

[0039] The other aspects of options A through D are illustrated respectively in Figures 3-6. In summary, it can be seen that option A includes four alternatives for 1 layer, eight alternatives for 2 layer, and one each for 3 layers, 4 layers, 7 layers, and 8 layers. By contrast, option B includes four alternatives for 1 layer, but only four alternatives for 2 layers, two alternatives for 3 layers, two alternatives for 4 layers, and one each for 5, 6, 7, and 8 layers. Option C includes eight alternatives for 1 layer, two alternatives for 2 layers, and one each for 3 through 8 layers. Finally, option D includes eight alternatives for 1 layer and four alternatives for 2 layers.

[0040] Certain embodiments may have various benefits and/or advantages. For example, there can be several ways to configure the antenna port(s), scrambling identity and number of layers indication. By allowing the flexibility to configure this table in a UE specific way an eNB may choose to prioritize among legacy operation, SU-MIMO, MU-MIMO operation appropriately. This can be achieved without adding to the DCI payload.

[0041] The above-described procedures at 210, 220, and 230 of Figure 2 can be performed by a node such as an access node, for example a base station or an eNB. Additionally, at 240 a UE can receive configuration for flexible MU- dimensioning. Furthermore, at 250, a UE can receive configuration for a decided MU-dimensioning table, such as any one of options A through D. Finally, at 260 and 265 respectively, the eNB and UE can operate based on the decided MU- dimensioning table. Thus, for example, the eNB and UE can communicate with one another based on the MU-dimensioning table.

[0042] Figure 7 illustrates a system according to certain embodiments of the invention. It should be understood that each block of the flowchart of Figure 2 may be implemented by various means or their combinations, such as hardware, software, firmware, one or more processors and/or circuitry. In one embodiment, a system may include several devices, such as, for example, access node 710 and user equipment (UE) or user device 720. The system may include more than one UE 720 and more than one access node 710, although only one of each is shown for the purposes of illustration. An access node can be for example, an access point, a base station, an eNode B (eNB), or any other network element. Each of these devices may include at least one processor or control unit or module, respectively indicated as 714 and 724. At least one memory may be provided in each device, and indicated as 715 and 725, respectively. The memory may include computer program instructions or computer code contained therein for carrying out the embodiments described above. One or more transceiver 716 and 726 may be provided, and each device may also include an antenna, respectively illustrated as 717 and 727. Although only one antenna each is shown, many antennas and multiple antenna elements may be provided to each of the devices. Other configurations of these devices, for example, may be provided. For example, access node 710 and UE 720 may be additionally configured for wired communication, in addition to wireless communication, and in such a case antennas 717 and 727 may illustrate any form of communication hardware, without being limited to merely an antenna.

[0043] Transceivers 716 and 726 may each, independently, be a transmitter, a receiver, or both a transmitter and a receiver, or a unit or device that may be configured both for transmission and reception. The transmitter and/or receiver (as far as radio parts are concerned) may also be implemented as a remote radio head which is not located in the device itself, but in a mast, for example. It should also be appreciated that according to the "liquid" or flexible radio concept, the operations and functionalities may be performed in different entities, such as nodes, hosts or servers, in a flexible manner. In other words, division of labor may vary case by case. One or more functionalities may also be implemented as a virtual application that is provided as software that can run on a server.

[0044] A user device or user equipment 720 may be a mobile station (MS) such as a mobile phone or smart phone or multimedia device, a computer, such as a tablet, provided with wireless communication capabilities, personal data or digital assistant (PDA) provided with wireless communication capabilities, portable media player, digital camera, pocket video camera, navigation unit provided with wireless communication capabilities or any combinations thereof. The user device or user equipment 720 may be a sensor or smart meter, or other device that may usually be configured for a single location.

[0045] In an exemplifying embodiment, an apparatus, such as an access node or user device, may include means for carrying out embodiments described above in relation to Figure 2.

[0046] Processors 714 and 724 may be embodied by any computational or data processing device, such as a central processing unit (CPU), digital signal processor (DSP), application specific integrated circuit (ASIC), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), digitally enhanced circuits, or comparable device or a combination thereof. The processors may be implemented as a single controller, or a plurality of controllers or processors. Additionally, the processors may be implemented as a pool of processors in a local configuration, in a cloud configuration, or in a combination thereof.

[0047] For firmware or software, the implementation may include modules or unit of at least one chip set (e.g., procedures, functions, and so on). Memories 715 and 725 may independently be any suitable storage device, such as a non-transitory computer-readable medium. A hard disk drive (HDD), random access memory (RAM), flash memory, or other suitable memory may be used. The memories may be combined on a single integrated circuit as the processor, or may be separate therefrom. Furthermore, the computer program instructions may be stored in the memory and which may be processed by the processors can be any suitable form of computer program code, for example, a compiled or interpreted computer program written in any suitable programming language. The memory or data storage entity is typically internal but may also be external or a combination thereof, such as in the case when additional memory capacity is obtained from a service provider. The memory may be fixed or removable.

[0048] The memory and the computer program instructions may be configured, with the processor for the particular device, to cause a hardware apparatus such as an access node 710 and/or UE 720, to perform any of the processes described above (see, for example, Figure 2). Therefore, in certain embodiments, a non- transitory computer-readable medium may be encoded with computer instructions or one or more computer program (such as added or updated software routine, applet or macro) that, when executed in hardware, may perform a process such as one of the processes described herein. Computer programs may be coded by a programming language, which may be a high-level programming language, such as objective-C, C, C++, C#, Java, etc., or a low-level programming language, such as a machine language, or assembler. Alternatively, certain embodiments of the invention may be performed entirely in hardware.

[0049] Furthermore, although Figure 7 illustrates a system including a access node 710 and a UE 720, embodiments of the invention may be applicable to other configurations, and configurations involving additional elements, as illustrated and discussed herein. For example, multiple user equipment devices and multiple access nodes may be present, or other nodes providing similar functionality, such as nodes that combine the functionality of a user equipment and an access point, such as a relay node.

[0050] It should be appreciated that future networks will most probably utilize network functions virtualization (NFV) which is a network architecture concept that proposes virtualizing network node functions into "building blocks" or entities that may be operationally connected or linked together to provide services. A virtualized network function (VNF) may comprise one or more virtual machines running computer program codes using standard or general type servers instead of customized hardware. Cloud computing or data storage may also be utilized. In radio communications this may mean node operations to be carried out, at least partly, in a server, host or node operationally coupled to a remote radio head. It is also possible that node operations will be distributed among a plurality of servers, nodes or hosts. It should also be understood that the distribution of labor between core network operations and base station operations may differ from that of the LTE or even be non-existent. Some other technology advancements probably to be used are Software-Defined Networking (SDN), Big Data, and all-IP, which may change the way networks are being constructed and managed.

[0051] Figure 8 illustrates a further system according to certain embodiments. As shown in Figure 8, a system can be arranged to provide configuration suitable for a multi-user operation according to certain embodiments. The system can be suitable for 3D-MIMO especially for FD-MIMO. In configuration, an access node 805 may choose to prioritize legacy, SU-MIMO or MU-MIMO operation UE- specifically.

[0052] As shown in Figure 8, an access node 805, such as an evolved Node B (eNB) of LTE-Advanced, base station or other suitable apparatus may include means for configuring 810 a user equipment (UE) 815 into a transmission mode supporting flexible MU-dimensioning operation. For signaling or other configuration indication purposes, this transmission mode may be named, for example as a transmission mode, TM 12. Another option is a new RRC signaling parameter indicating the flexible mode. The configuration and other communication between the access node 805 and user equipment 815 may take place over one more wireless communication link 825.

[0053] The access node 805 may also include means for deciding 820 a MU dimensioning table for one particular UE, on a UE-specific basis - such as, for example, deciding a particular MU dimensioning table for UE 815. The decision may be based on a cell load, traffic quality of service (QoS) type, buffer status, UE channel quality indicator (CQI), geometry and/or downlink control channel overhead, etc. Some examples of suitable MU dimensioning tables are put forward in Figures 3-6, as explained above.

[0054] The access node 805 may further include means for configuring 830 the decided MU dimensioning table to UE 815. This configuration may be carried out by using radio resource control (RRC) signaling from a eNB, such as access node 805, to the UE 815. The signaling may be identifying one of the candidate tables to be used or individually configuring each entry of the table: For each entry of the MU-dimensioning table, the RRC configuration may include at least one of the following: number of layers, which port to be used for each layer and SCID (scrambling identity SCM (spatial channel model) for DMRS (demodulation reference signal) sequence generation. In one embodiment, access node 805 can send a DCI message including one or more bits indicating which entry in the configured MU-dimensioning table UE 815 is supposed to use for a PDSCH transmission.

[0055] Thus, in certain embodiments, there can be UE specific MU dimensioning configuration. For example, the bits for Antenna port(s), scrambling identity and number of layers indication in downlink control information (DCI) can be configured through higher layer signaling in a UE specific manner.

[0056] The MU dimensioning or configuration tables presented in the examples above were obtained by simulations. Using the means for deciding 820, a node such as access node 805 can choose a suitable table from a predetermined set of candidate tables, for example, the examples in Figures 3-6, as explained above.

[0057] The above-described means 810, 820, and 830 of Figure 8 can be included in a node such as an access node 815, which may, for example, be a base station or an eNB. Additionally, UE 815 can include means for receiving 840 configuration for flexible MU-dimensioning. Furthermore, UE 815 can include means for receiving 850 configuration for a decided MU-dimensioning table, such as any one of options A through D. Finally, access node 805 and UE 815 can include include means for operating 805 and 815 based on the decided MU- dimensioning table. Thus, for example, the access node 805 and UE 815 can communicate with one another based on the MU-dimensioning table.

[0058] The various means illustrated in Figure 8 may be implemented in a variety of different ways such as, but not limited to, implementation with devices as shown in Figure 7, having processor(s), memory(ies), and the like. Other implementations are also permitted.

[0059] One having ordinary skill in the art will readily understand that the invention as discussed above may be practiced with steps in a different order, and/or with hardware elements in configurations which are different than those which are disclosed. Therefore, although the invention has been described based upon these preferred embodiments, it would be apparent to those of skill in the art that certain modifications, variations, and alternative constructions would be apparent, while remaining within the spirit and scope of the invention. In order to determine the metes and bounds of the invention, therefore, reference should be made to the appended claims.

[0060] List of Abbreviations

[0061] CQI Channel Quality Indicator

[0062] CRS Common (Cell-specific) Reference Signal

[0063] CSI Channel State Information

[0064] CSI-RS Channel State Information Reference Signal

[0065] BLER Block Error Rate

[0066] DCI Downlink Control Information

[0067] DL Downlink

[0068] DM RS Demodulation Reference Signal (User specific)

[0069] eNB, eNodeB Base Station

[0070] ePDCCH enhanced Physical Downlink Control Channel

[0071] HARQ Hybrid Automatic Repeat Request

[0072] LTE Long Term Evolution

[0073] MIMO Multiple Input Multiple Output

[0074] NZP Non Zero Power

[0075] PDCCH Physical Downlink Control Channel

[0076] PMI Precoding Matrix Indicator

[0077] PMI-RS Precoding Matrix Indicator Reference Signal (Precoded RS for PMI selection)

[0078] PRB Physical Resource Block

[0079] PUCCH Physical Uplink Control Channel

[0080] PUSCH Physical Uplink Shared Channel

[0081] PDSCH Physical Downlink Shared Channel [0082] QAM Quadrature Amplitude Modulation

[0083] QPSK Quadrature Phase-Shift Keying

[0084] RE Resource Element

[0085] RI Rank Indicator

[0086] RRC Radio Resource Control

[0087] RNTI Radio Network Temporary Identifier

[0088] SNR Signal to Noise Ratio

[0089] SINR Signal to Interference plus Noise Ratio

[0090] TB Transport Block

[0091] TBS Transport Block Size

[0092] TDD Time Division Duplexing

[0093] TTI Transmission Time Interval

[0094] UE User Equipment, e.g. mobile terminal

[0095] UL Uplink

[0096] VCI Virtual Channel Identifier

Claims

WE CLAIM:

1. A method, comprising:

deciding a multi-user dimensioning table for a user equipment on a peruser-equipment basis; and

configuring the decided multi-user dimensioning table to the user equipment.

2. The method of claim 1 , further comprising:

configuring the user equipment into a transmission mode supporting flexible multi-user dimensioning operation.

3. The method of claim 1 or claim 2, wherein the deciding is based on at least one of cell load, traffic quality of service type, buffer status, user equipment channel quality indicator, geometry, or downlink control channel overhead.

4. The method of any of claims 1-3, wherein configuring the decided multiuser dimensioning table comprises signaling to the user equipment using radio resource control signaling.

5. The method of any of claims 1-4, wherein the deciding comprises deciding the parameters of each entry of the table, wherein the parameters of each entry comprise number of layers, antenna port for each layer, and scrambling ID.

6. The method of claims 1-5, wherein the deciding comprises selecting one of a set of predetermined candidate tables as the multi-user dimensioning table.

7. The method of any of claims 1-6, wherein the method is performed by an access node.

8. A method, comprising:

receiving, from an access node, a configuration of a multi-user dimensioning table selected from a plurality of multi-user dimensioning tables; and

operating a user equipment based on the received configuration of the multi-user dimensioning table.

9. The method of claim 8, further comprising:

receiving configuration for flexible multi-user dimensioning, wherein the operating is based on the configuration for flexible multi-user dimensioning and the received configuration of the multi-user dimensioning table.

10. The method of claim 8 or claim 9, wherein the multi-user dimensioning table comprises at least one of a set of predetermined candidate tables.

11. An apparatus, comprising:

at least one processor; and

at least one memory including computer program code,

wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to

decide a multi-user dimensioning table for a user equipment on a per-user- equipment basis; and

configure the decided multi-user dimensioning table to the user equipment.

12. The apparatus of claim 11 , wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to configure the user equipment into a transmission mode supporting flexible multi-user dimensioning operation.

13. The apparatus of claim 11 or claim 12, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to decide the multi-user dimensioning table based on at least one of cell load, traffic quality of service type, buffer status, user equipment channel quality indicator, geometry, or downlink control channel overhead.

14. The apparatus of any of claims 11-13, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to configure the decided multi-user dimensioning table by signaling to the user equipment using radio resource control signaling.

15. The apparatus of any of claims 11-14, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to decide the parameters of each entry of the table, wherein the parameters of each entry comprise number of layers, antenna port for each layer, and scrambling ID.

16. The apparatus of claims 11-15, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to select one of a set of predetermined candidate tables as the multi-user dimensioning table.

17. The apparatus of any of claims 11-16, wherein the apparatus comprises an access node.

18. An apparatus, comprising:

at least one processor; and

at least one memory including computer program code,

wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to receive, from an access node, a configuration of a multi-user dimensioning table selected from a plurality of multi-user dimensioning tables; and

operate a user equipment based on the received configuration of the multiuser dimensioning table.

19. The apparatus of claim 18, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to receive configuration for flexible multi-user dimensioning and to operate based on the configuration for flexible multi-user dimensioning and the received configuration of the multi-user dimensioning table.

20. The apparatus of claim 18 or claim 19, wherein the multi-user dimensioning table comprises at least one of a set of predetermined candidate tables.

21. A computer program product encoding instructions for performing the method according to any of claims 1-10.

22. A non-transitory computer readable medium encoded with instructions that, when executed in hardware, perform a process, the process comprising the method according to any of claims 1-10.

23. An apparatus comprising means for carrying out the method according to any one of claims 1 to 10.