Patent Description:
Control channels for Uplink (UL) and Downlink (DL) New Radio (NR) have a beam centric architecture. While the NR Downlink Control Information (DCI) is precoded, the DL control signaling on multiple beams is currently undefined. Protocols to support channel estimation for DL control signals are needed in NR.

In high carrier frequencies, phase noise becomes a significant problem Tracking RS (TRS) aids in estimating and compensating for phase noise. Resource allocations for Demodulation Reference Signals (DMRS) and TRS have not been finalized in NR.

SRS design for UL, especially in a beam centric architecture, has not been addressed in NR. Techniques for assigning SRS resources on multiple beams and in multiple numerologies is needed.

Currently in LTE, Channel State Information Interference Channel Measurement (CSI-ICM) is used to measure the interference power configured in RRC signaling. Interference may be caused by MIMO transmissions or beams from similar or different Transmission and Reception Points (TRP)s. As the number of interference sources increase, the number of interference hypotheses exponentially increase in turn. Because one CSI-ICM resource is required for each interference hypothesis, a large overhead for DL transmission is realized. This potentially limits a NR node's flexibility for scheduling MU-MIMO.

In order to facilitate a more robust understanding of the application, reference is now made to the accompanying drawings, in which like elements are referenced with like numerals. These drawings should not be construed to limit the application and are intended only to be illustrative.

A detailed description of the illustrative embodiment will be discussed in reference to various figures, embodiments and aspects herein. Although this description provides detailed examples of possible implementations, it should be understood that the details are intended to be examples and thus do not limit the scope of the application.

Reference in this specification to "one embodiment," "an embodiment," "one or more embodiments," "an aspect" or the like means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the disclosure. Moreover, the term "embodiment" in various places in the specification is not necessarily referring to the same embodiment. That is, various features are described which may be exhibited by some embodiments and not by the other.

Generally, the application is directed to methods and systems for reference signal designs and control channel designs for NR systems. In order to meet the requirements of the NR systems, enhancements related to reference signal and control channel design for NR can be employed. The application is also directed to mechanisms for control channel designs including techniques to assign resources for NR-DCI and waveforms for UL signaling. Mechanisms to aid control channel estimation and allocation of UL and DL resources within sub-bands can limit the computational burden on the UE.

Another aspect of the application is directed to mechanisms for reference signal designs. Solutions for DMRS and TRS design for NR are employed. Mechanisms can support resource allocation and cell/beam wide RS allocation and UE-specific RS allocation.

Resource allocation for NR-SRS in multiple beams and across multiple numerologies are described. Precoded SRS can be supported. Mechanisms for CSI based measurements are described. The following methods can enable CSI ICM and can make it more efficient: (i) A new RRC signaling, informs the UE about necessary information of configuration, such as RS location, code book information; (ii) a CSI-ICM resource set where CSI-ICM resources within the set may be dynamically shared among UEs. A two-step CSI-ICM configuration to support CSI-ICM and reduce the latency. Step <NUM> is to pre-configure a set of K CSI-ICM resources for all the UEs through RRC signaling. In step <NUM>, for a given UE, dynamically indicate N (N >= <NUM>) CSI-ICM resources from a total of K based on the interference hypothesis to enable CSI-ICM measurement by dynamic signaling through DCI or dynamic signaling through MAC CE.

According to another embodiment, group-based CSI-ICM configuration through DCI is used to enable multiple UEs measuring the interference channel. The UEs can be grouped by experiencing the same interference hypothesis. According to yet another embodiment, a new NR PUCCH format to support CSI-ICM reporting is envisaged. In yet another embodiment, a new NR DCI design is envisaged to enable UE interference cancellation for MU-MIMO. In yet another embodiment, a procedure of interference channel measurement and interference cancellation for NR MU-MIMO is described.

According to another aspect, mechanisms for dynamic CSI-RS resource allocation are described. Two methods for RRC based configuration of CSI-RS pooling resources are envisaged. In the first technique, a UE-specific CSI-RS resources configuration is employed without configuration of a group of UEs sharing the same CSI-RS resource pool. In a second technique, a UE-specific CSI-RS resources configuration is employed with configuration of a group of UEs sharing the same CSI-RS resource pool.

Several signaling designs to dynamically indicate UE's CSI-RS resource and reporting are described (i) CSI measurement command signaled in MAC CE; and (ii) CSI measurement command signaled in DCI including: (a) CSI measurement command piggyback on DCI; (b) Standalone CSI measurement command (sent on a separate DCI) for a specific UE; and (c) Group-based DCI to schedule multiple UEs' CSI-RS measurement and feedback.

The mechanisms discussed herein may be conducted at the NR-node, Transmission and Reception Point (TRP) or Remote Radio Head (RRH). Accordingly, it is envisaged that the NR-node, TRP and RRH are interchangeable even though the NR-node is used in most exemplary descriptions or illustrations.

The time interval contains DL and/or UL transmissions are flexible for different numerologies and RAN slices and may be statically or semi-statically configured. The time interval structure may be used for a slot or a mini-slot within a subframe. The mechanisms for this time interval structure may be applicable to slot and/or mini-slot even though the exemplary descriptions and/or illustration figures use slot or mini-slot.

The following acronyms are used for the terms and phrases below:.

DL Reference Signals (RS)s are predefined signals occupying specific Resource Elements (RE)s within the downlink time-frequency RE grid. The LTE specification includes several types of DL RSs transmitted in different ways for different purposes [<NPL>].

Cell-specific Reference Signals (CRS): CRS are used: (<NUM>) by User Equipments (UEs) for channel estimation for coherent demodulation of DL physical channels; and (<NUM>) by UEs to acquire Channel State Information (CSI); (<NUM>) by UEs for measurements of cell-selection and handover.

Demodulation Reference Signals (DM-RS): DM-RS are referred to as UE-specific reference signals, and are (<NUM>) used for channel estimation by a specific UE and only transmitted within the RBs specifically assigned for PDSCH/ePDCCH transmission to that UE, and (<NUM>) associated with data signals and precoded prior to the transmission with the same precoder as data.

Channel State Information Reference Signals (CSI-RS): CSI-RS are intended to be used by UEs to acquire CSI for channel-dependent scheduling, link adaptation and multi-antenna transmissions.

Similar to LTE DL, reference signals are also used in LTE UL. Two types of reference signals are defined for LTE UL ["<NUM> LTE/LTE-Advanced for Mobile Broadband"].

UL Demodulation Reference Signals (DM-RS): DM-RS is used by the base station for channel estimation for coherent demodulation of Physical Uplink Shared Channel (PUSCH) and Physical Uplink Control CHannel (PUCCH). DM-RS are only transmitted within the RBs specifically assigned for PUSCH/PUCCH transmission and are spanning the same frequency range as the corresponding physical channel.

UL Sounding Reference Signals (SRS): SRS is used by the base station for CSI estimation for supporting uplink channel-dependent scheduling and link adaptation. SRS are also used for the base station to obtain CSI estimation for DL under the case of channel reciprocity.

DL channel-dependent scheduling is a key feature of LTE, which selects the DL transmission configuration and related parameters depending on the instantaneous DL channel condition, including the interference situation. To support the DL channel-dependent scheduling, a UE provides the CSI to the evolved Node B (eNB). The eNB uses the information for its scheduling decisions.

The CSI consists of one or several pieces of information ["<NUM> LTE/LTE-Advanced for Mobile Broadband"] including:.

Rank Indication (RI): provide a recommendation on the transmission rank to use or, number of preferred layers that should be used for PDSCH transmission to the UE.

Precoder Matrix Indication (PMI): indicate a preferred precoder to use for PDSCH transmission.

Channel-Quality Indication (CQI): represent the highest modulation-and-coding scheme to achieve a block-error probability of at most <NUM>%.

Together, a combination of the RI, PMI, and CQI forms a CSI feedback report to eNB. What is included in the CSI report depends on the UE's configured reporting mode. For example, RI and PMI do not need to be reported unless the UE is in a spatial multiplexing multi-antenna transmission mode.

The Downlink Control Information (DCI) is a predefined format in which the DCI is formed and transmitted in Physical Downlink Control Channel (PDCCH). The DCI format tells the UE how to get its data which is transmitted on Physical Downlink Shared Channel (PDSCH) in the same subframe. It carries the details for the UE such as number of resource blocks, resource allocation type, modulation scheme, redundancy version, coding rate, etc., which help UE find and decode PDSCH from the resource grid. There are various DCI formats used in LTE in PDCCH.

Currently, 3GPP standardization efforts are underway to define the NR frame structure. Consensus is to build the so called 'self-contained' time intervals for NR. As illustrated in <FIG>, a self-contained time interval is understood to contain the control information for a grant, the data and it's acknowledgement (i.e. ACK/NACK) all within a time interval and is expected to have configurable UL/DL/side link allocations and reference signals within its resources [<NPL>].

3GPP TR <NUM> [<NPL>] defines scenarios and requirements for New Radio (NR) technologies. The Key Performance Indicators (KPIs) for eMBB, URLLC and mMTC devices are summarized in Table <NUM> below.

The following has been agreed upon at the 3GPP RANI #86bis meeting for the NR Reference Signal (RS) supported for downlink:.

CSI-RS: Reference signal with main functionalities of CSI acquisition, beam management.

DM-RS: Reference signal with main functionalities of data and control demodulation.

At least the following RSs are supported for NR uplink:.

DL channel-dependent scheduling is a key feature of LTE, which selects the DL transmission configuration and related parameters depending on the instantaneous DL channel condition, including the interference situation. To support the DL channel-dependent scheduling, UE provides the CSI to the evolved Node B (eNB). The eNB uses the information for its scheduling decisions.

The CSI consists of one or several pieces of information: (i) Rank Indication (RI); (ii) Precoder Matrix Indication (PMI); (iii) Channel-Quality Indication (CQI). Together, a combination of the RI, PMI, and CQI forms a CSI feedback report to eNB. What is included in the CSI report depends on the UE's configured reporting mode. CSI report could be configured to be periodic or aperiodic by RRC signaling.

Aperiodic reporting is triggered by DCI formats, and could be used to provide more detailed reporting via PUSCH. A UE is semi-statically configured by higher layer to feedback CQI and PMI and corresponding RI on the same PUSCH using one of the following CSI reporting modes given in Table <NUM> below. In sub-frame n, a CSI request can be transmitted in DCI format <NUM> and DCI format <NUM>, which schedule a PUSCH transmission that carry aperiodic CSI report in sub-frame n+k.

For each of the transmission modes in Table <NUM> above, different reporting modes are defined and supported on PUSCH.

For periodic CSI reporting, UE is semi-statically configured by higher layers to periodically feedback different CSI components (CQI, PMI, and/or RI) on the PUCCH using the reporting modes given in Table <NUM>. The periodic CSI reporting is configured by higher layer signaling (RRC).

For each of the transmission modes defined in Table <NUM> above, different periodic CSI reporting modes are defined and supported on PUCCH.

According to an aspect of the application, architectures and techniques for DL and UL control signals for NR are provided. Solutions are described herein for resource allocation and reference signal design for NR-DCI.

In one embodiment, NR-DCI resource allocation in a beam centric architecture is described. Here, the 3GPP spec can support transmission of NR-DCI on multiple beams to improve coverage and reliability. Note that LTE supported only broadcast of the PDCCH. The beams may sweep through different spatial locations carrying NR-DCI as shown in <FIG>.

In this proposal, the beams carrying control information sweep through the space before the UL/DL grant resources are made available as shown in <FIG>. The DL grant is available N symbols after the control signaling. The advantage of this scheme is that latency is reduced in decoding important control signaling related to paging, RACH, etc..

If the UE location is known a-priori, its UE-specific NR-DCI can be transmitted only in a subset of the beams. If the UE location is not known to the NR-Node, its NR-DCI may be transmitted in every beam. This concept in illustrated in <FIG> where the control region is swept by <NUM> beams covering symbol per beam. A UE-specific NR-DCI is repeated in all the beams in <FIG> but transmitted only in beams <NUM> and <NUM> in <FIG>. The NR-DCI may be located in different subcarriers in different beams.

Similarly, NR-DCI for common control signaling may be carried in every beam. The common control search space uses the same subcarriers in all the beams carrying the control information - minimizes the overhead to indicate different common control signaling resources for each beam.

In another embodiment, each beam may carry multiple symbols including control and data as shown in <FIG> where the NR-DCI in the beam may allocate resources for an UL and/or DL grant in the same beam. The advantage of this scheme is that the latency between the control and data is minimal. Generally, for the schemes described above, control and data transmission could occur in different beams, For example, beams for control signaling may be wider than those for data signaling.

According to another embodiment, solutions for RS design for NR are proposed. Certain types of NR-DCI such as common control signals may be transmitted for beam-wide reception. The NR-DCI can leverage the beam-RS which is intended for identifying a beam and for measurements of a beam for also estimating the channel.

If NR-DCI is transmitted through multiple ports (as in transmit diversity) a new form of "Control-RS" with appropriate density may be introduced to aid channel estimation of NR-DCI. This control-RS would be transmitted for each port that is supported for NR-DCI transmission. This control-RS may be cell/beam specific and its location and resources may depend on one or more of the following: (i) Cell ID; and (ii) Beam ID.

The control-RS may be transmitted to cover channel estimation for the entire frequency range of the DCI symbols or may be transmitted in a limited region where DCIs transmitted with those ports are mapped in frequency.

<FIG> illustrates the beam-RS and control-RS ports. The control-RS may be defined for more than <NUM> port. The resources for multiple ports may be defined with orthogonal covering codes similar to the OCCs for DMRS ports in LTE.

Certain types of NR-DCI, especially UE-specific signals may be precoded to improve spatial separation and coverage. For such use cases, "control-DMRS" may be introduced to aid in channel estimation.

<FIG> shows a Control DMRS used in UE-specific manner to decode the NR-DCI. The NR-DCI may be transmitted on multiple ports (transmit diversity or beamforming) and correspondingly the control-DMRS would be precoded similar to the precoded NR-DCI and will be supported on the ports used for data transmission. If the data and control are transmitted on the same beam, they may share the control-RS or control-DMRS resources.

<FIG> shows a control DMRS shared between control and data region if they are precoded in the same way. The beam-RS, control-RS and control-DMRS can be located in close proximity to the control region to provide high control channel reliability.

According to yet another embodiment, the NR-DCI may use a fixed number of control signals or fixed duration for control signaling in every transmission interval. This could be a slot or mini-slot or subframe. For such a design, NR does not need to transmit a PCFICH-like channel as the control signaling resource is fixed. The control signaling resource may be indicated through critical system information such as the MIB or SIB1/SIB2 or may be set to fixed values in the spec.

<FIG> shows an example where the number of control signals is the same in every transmission interval. <FIG> shows an example where the duration of the control signaling is the same for all numerologies multiplexed in FDM/TDM in the resource grid. So a transmission interval using <NUM> subcarrier spacing uses <NUM> symbols for control signaling whereas a transmission interval operating at <NUM> uses <NUM> symbol for control signaling within that transmission interval. This solution ensures that the beams sweeps in every direction for the same period of time.

Alternatively, the spec may specify the number of symbols for each numerology. The number of symbols may depend on one or more of the following: (i) center frequency; (ii) bandwidth; and (iii) number of beams supported.

According to a further embodiment, NR has support for large bandwidths exceeding <NUM>. If a UE is required to blindly decode the NR-DCI across the entire bandwidth it will experience significant latency and battery drain. As a result, NR must allow transmission of the NR-DCI to a UE in specific subbands. The UE must be configured to have knowledge of the resources of these subbands.

The UE-specific NR-DCI may be indicated within a limited number of resources (subbands) which are known apriori at the UE. The subbands may be configured semi-statically through RRC and MAC CE updates. <FIG> shows an example where the NR-DCI is carried in UE-specific subbands. The subbands may be allocated based on UE capabilities, i.e. the UE may inform the network about the maximum bandwidth that it can process at a time. Note that the subbands allocated to a UE need not be contiguous in frequency.

The search space for common control signaling may carry NR-DCI such as those for paging, RACH response, etc. be limited to specific subands so that UEs do not have to blindly decode all the resources in the common control signaling search space.

The common control signaling search space may be partitioned into multiple search spaces and UE may be assigned to search for the common NR-DCI only within a subset of those search spaces. <FIG> shows an example where the common signaling search space is partitioned into <NUM> search spaces and a UE is configured to search for its common NR-DCI only within <NUM> of those spaces.

Similar to the solution described above for subband operation for UE-specific and common NR-DCI, Physical DL shared channel (NR-PDSCH) carrying the data may also be restricted to subbands. This limits the number of times the UE's front end has to be re-tuned to a new frequency for reception. The subbands for NR-PDSCH may be semi-statically configured through RRC and MAC CE updates. <FIG> shows an example where the NR-PDSCH for a UE is transmitted over preconfigured subbands; so the UE is tuned to perform reception of data only over the range of frequencies covering the subbands.

According to a further embodiment, the UE may be configured to transmit within a subband rather than the entire bandwidth to limit the amount of front end and receiver processing. Accordingly the UL resources would be constrained within a subband. The subband may be preconfigured semi-statically through RRC or MAC CE updates or specified dynamically through the UL grant.

<FIG> shows example of resource allocation for UL transmission for CP-OFDM or DFTS-OFDM within a subband. Here one or more subbands are allocated to the UE within which the UE is provided its UL grant. Similarly, for UL grantless transmission, a subband of frequencies may be indicated to a UE to transmit its grantless signal. When resource hopping is used, the UE may transmit within one or more subbands and the hopping resources may not occupy the entire bandwidth.

In an embodiment, it is envisaged that the waveform (CP-OFDM or DFT-S-OFDM) is assigned to a UE by the network. Here, the NR-Node makes the decision for the UE on which waveform to use. NR-Node can decide the waveform for the UE based on feedback from UE (such as beam or cell measurements or CQI) or from SRS or other RS on the UL. The configuration of the waveform may be done in the following ways:.

According to another aspect of the application, it is envisaged to support a wide range of user mobility scenarios with low-latency in NR, reference signaling may be enhanced in DL NR. DM-RS location within a slot/mini-slot or subframe should be flexible and adaptive to scenario-specific performance requirements. For example, <FIG> shows that DM-RS could be front-loaded, bringing two-fold advantages. Firstly, the proximity of DM-RS to control data allows accurate estimation channel at control data resources, thereby rendering accurate demodulation/decoding of control data. Secondly, an early DM-RS will minimize the delay in demodulation/decoding by delivering channel estimates early on. These two advantages make it very suitable for the use case of URLL.

<FIG> shows support for two ports via OCC. In general support for N-layers can be achieved via appropriate codes. <FIG> further show three examples of suggested placement of DM-RS. <FIG> shows that DM-RS may be placed in the middle of a transmission interval so that channel estimates obtained over the entire duration of the interval are more accurate compared to having front-loaded DM-RS. Although the latency is higher for decoding control information, mMTC and eMBB may be able to tolerate the latency.

<FIG> shows DMRS allocated with higher density in the transmission interval. For example, for high Doppler scenarios, the DM-RS may be allocated in multiple symbols spread over time, to enable accurate channel estimation.

For a scenario where the UEs have low mobility, the DM-RS could be placed at the end of a minislot 'i'', and be used to provide channel estimates to subframes 'i' and 'i+<NUM>'. Similarly, DM-RS can be shared between multiple UEs. For UEs <NUM> and <NUM> that have consequent RBs in the same band, the DM-RS could be placed at the end of subframe '<NUM>', and be used to provide channel estimates to two subframes belonging to different users. <FIG> illustrates the aforementioned scenarios.

In <FIG>, DM-RS is shared between two sub-frames for low mobility, high throughput scenarios: (a) Sharing between two subframes of the same user; and (b) Sharing between subframes of two different users precoded the same way.

NR can support PRB bundling and allow flexible location of DMRS resources in the bundled PRBs. In <FIG>, two bundled PRBs with different DM-RS patterns undergo the same precoding. PRB1 may have the DMRS allocated in a manner where it can be shared with a neighboring UE. But PRB <NUM> may have lower density of DMRS allocation.

The resource assignment of DM-RS can be either dynamic or semi-static. Dynamic signaling can be done through DCI. The specification may specify a list of possible DM-RS patterns (locations and sequences) out of which one may be assigned to a UE. The assigned resource may be indicated through an index into the list. When semi-static signaling is used, RRC or MAC CE updates will indicate the DM-RS configurations. It is envisaged the DM-RS will in general have same numerology as data.

In an embodiment, Tracking Reference Signals (TRS) for phase tracking in NR is described. Here, phase noise increases with increasing carrier frequency, thereby making it an important issue to solved in NR. The following solutions address phase tracking in NR.

TRS may not be sent all the time. Tracking RS need only be sent when needed and not always. This is important to avoid costly transmission overhead brought by TRS transmission. One or more of the following factors may influence the choice of switching TRS on or off:.

Modulation order: The absence of phase tracking RS will have a much more deteriorating effect on BLER when data is higher order modulated compared to when it is lower order modulated.

Carrier frequency: Increasing carrier frequency will necessitate the need turn on Tracking RS.

UE speed: Increasing UE speed will increase the Doppler implying the need to turn on Tracking RS.

Sub-carrier Spacing: Increased sub-carrier spacing will increase inherent immunity of system to carrier frequency offset, thereby reducing the need for Tracking RS.

TRS may be UE specific or cell specific. On/Off signaling for tracking RS may be done via distinct signaling depending on whether it is UE specific or cell-specific. If it is UE specific then it may be configured via RRC signaling and turned on/off through RRC signaling/MAC CE updates or dynamically through the DCI. If TRS is cell/beam wide then system information may be used to signal its presence and resources.

<FIG> shows the cell/beam wide case where TRS resources are assigned in specific locations in the grid. Enough TRS resources may be reserved so that UEs that may operate only in certain subbands of available spectrum can access the TRS. <FIG> shows the UE specific case where each UE can have TRS resources assigned according to its SNR, modulation, numerology, etc..

In case of UE specific TRS, tracking RS may be precoded. In addition, location and sequence of Tracking RS may depend on one or more of beam ID, cell ID, and UE specific resources, such as for example, a root/shift of a sequence assigned to the UE or location of the DL resources for the UE.

In case of cell/beam wide TRS, TRSs are transmitted in resources that are known to all UEs. TRSs could be a function of one or more of: (a) Cell ID; and (b) Beam ID. TRS transmission could be configured on one or more ports. In some instances, it may be sufficient to track phase by transmitting TRS on a single port. As a result, TRS on a single port may be supported by default. However, NR must also support more ports for TRS. The resources for the ports maybe configured for both cell/beam wide and UE specific use cases through DCI or RRC signaling.

According to yet another embodiment, NR Sounding reference signal on UL (NR-SRS) is described. Since NR will support different numerologies, NR-SRS numerology and resources must allocated in a manner compatible with all supported data and control signal numerologies and TDM/FDM multiplexing of multiple users. The following solutions can address NR-SRS signaling aspects when multiple numerologies are supported simultaneously in a carrier. NR-SRS resource signaling may fall into one of the categories described below where the NR-Node can allocate any of the following resources for NR-SRS transmission:.

Alternatively, the SRS resources may be defined in units of time and may be configured to support any numerology. In this case, the reserved time may carry a different number of NR-SRS symbols for different numerologies. This concept is illustrated in <FIG> where NR-SRS resource is reserved for a fixed duration T. Different numerologies may be used within this duration, for example, <NUM> symbol of NR-SRS at <NUM> subcarrier spacing (Numerology <NUM>), or <NUM> symbols of NR-SRS at <NUM> subcarrier spacing (Numerology <NUM>).

In an embodiment, a UE may transmit NR-SRS on multiple beams in a reserved SRS resource. This concept is illustrated in <FIG>. Each NR-SRS symbol is reserved for a certain beamforming direction. It is envisaged that these solutions can apply to a self-contained subframe as well.

In another embodiment, SRS port mapping techniques may be used to support non-precoded, precoded and beamforming. The NR-SRS port mapping methods for non-precoded, precoded, and beamforming cases are described.

In an exemplary embodiment, the UE may transmit a maximum number of ports that it can support and feedback to NR-NB. The maximum number of available, supported ports may be dependent on UE capability. Here, a unified method for NR-SRS port mapping for non-precoded, precoded and beamforming can be employed. The porting mapping can work with the UL antenna virtualization. The antenna virtualization method is depicted in the following <FIG>. The antenna virtualization can be partitioned into four stages. The first stage performs digital precoding or beamforming via generation of VD. After applying antenna virtualization, the effective precoding/beamforming matrix/vectorV from <FIG> can be expressed as: <MAT> where the VD is the codebook that can be defined or specified in the digital domain, VA is the codewords to port mapping matrix, the VP is the port to TXRU mapping matrix and VT is the TXRU to physical antenna mapping.

If there is no precoding or beamforming applied on the NR SRS, then the NR SRS can be directly transmitted via the port configured/assigned from NR gNB. In other words, the VD Vp and the VT can be set as an identify matrix, and the VA is dependent on the NR-SRS port configuration setting. For example, if a UE can support up to <NUM> ports and the RRC configuration parameters srs-TxAntennaPorts is set to {<NUM>, <NUM>, <NUM>, <NUM>}, then UE can transmit NR-SRS to ports <NUM>, <NUM>, <NUM> and <NUM>. The active port number may be dynamic signaling via DL DCI. In an instance, if the configuration parameter srs-TxAntennaPorts is set to {<NUM>, <NUM>, <NUM>, <NUM>} and NR configure the transmission active port as {<NUM>, <NUM>, <NUM>} at a certain SRS transmission subframe then the UE transmit the NR-SRS on port {<NUM>, <NUM>, <NUM>} only. If there is no DL DCI is involved in the transmission port configuration then the UE can transmit the NR-SRS based on the RRC configuration ports setup. The NR-SRS transmit at the different port may be transmitted at the same or different CP-OFDM/DFT-S-OFDM symbol and can be associated with a specific numerology. In <FIG>, NR-SRS set up at different transmission port is configured to transmit at different CP-OFDM/DFT-S-OFDM symbol.

Similarly, when there is a precoded or beamforming involved in the NR-SRS, the VD, VP and VT can be properly design to meet the precoding or beamforming requirement. The VA can be decided from the SRS port mapping configuration. In short, the following NR-SRS port mapping methods can be used:.

Here, the Vp and the VT can leave to UE implementation and without standardization effort.

According to yet a further embodiment, NR-SRS beam sweeping can be treated as a unit of beam sweeping time for transmitting NR-SRS. Each NR-SRS beam sweeping block may include at least one or more CP-OFDM/DTF-S-OFDM symbols and be associated with a specific numerology. Multiple beam sweeping blocks can form a beam sweeping burst. This is shown in <FIG>. The NR-SRS beam sweeping burst can be either configured as periodic or aperiodic transmission via semistatic RRC signaling or dynamic configuration via DL DCI. The SRS beam sweeping block can be associated with a single beam or multiple beams.

According to yet another aspect of the application, solutions to support CSI-ICM in NR are envisaged. In one embodiment, a new RRC signaling is employed to signal to the CSI-ICM. In another embodiment, two-step dynamic signaling is described. In yet another embodiment, a group based CSI-ICM configuration through DCI is described. In yet a further embodiment, the PUCCH format for CSI-ICM reporting is described. In yet even a further embodiment, the DCI design enables UE interference cancellation for MU-MIMO. In even a further embodiment, procedures of interference channel measurement and interference cancellation is described below.

According to this aspect, a new information element CSI-ICM-Config is used as the only signaling to indicate all the necessary information of the configuration is described. For example, the NR node configured the UE using the RRC signaling with the CSI-RS/ICM location. This could be based on one or more of the following: (i) UE interference hypotheses, (ii) the number of interference channel; and (iii) multiuser MIMO scheduling. Meanwhile, the information of precoding matrix used in the CSI-ICM transmission also need to be indicated. This is because the UE want to measure the real interference channel, so the precoding matrix need to be removed from the effective channel and the interference channel information can be feedback to the NR node. An example of CSI-ICM configuration information element CSI-ICM-Config in the RRC configuration message is listed below as follows:
<IMG>.

Alternatively, the technique may implement the CSI-ICM configuration by two steps signaling via NR DCI to avoid the large latency issue introduced by the RRC only signaling method. The steps are as follows:.

Step <NUM>: Initial resource set configuration through RRC signaling. Here, a set of K CSI-ICM resources are pre-configured for all the UEs through RRC information element CSI-ICMset-Config to indicate all the available CSI-RS/ICM location used for CSI_ICM. An example of information element CSI-ICMset-Config in the RRC message is listed as follows.

Step <NUM>: Dynamic CSI-ICM configuration signaling through NR DCI. Here, for a given UE, the NR node indicates N out of K (where N >= <NUM>) of the CSI-ICM resources from the set based on the interference hypothesis to enable CSI-ICM by dynamic signaling through a configurable DCI or dynamic signaling through MAC CE. The value of N increases as the number of interference sources increases. By introducing the second step, it can reduce the latency in the CSI-ICM configuration comparing to the RRC only signaling. For each UE in different interference hypotheses, the DCI information may be different, in terms of the number of the CSI-ICM resources and location, CSI-ICM feedback configuration and UL resources to transmit the CSI-ICM feedback if applicable. An example of the configurable fields for DCI scheme are listed in Table <NUM> below. One or more or all of the fields may be used to configure the DCI.

As an alternative method, the dynamic CSI-ICM configuration can be also done through MAC Control Element (CE) once the resources set is pre-configured. A new MAC Control Element, CSI-ICM configuration MAC control element which carries the similar information as that defined in Table <NUM> is defined below:.

The CSI-ICM configuration MAC control element may be defined over a fixed number n of octets. The CSI-ICM configuration MAC control element may be identified with Logical Channel Identifier (LCID), which may be one of the existing reserved value of LTE downlink logical channels between the range <NUM> and <NUM> (binary coding) or alternatively the LTE logical channel value ranges may be extended with new defined values assigned to CSI-ICM configuration MAC CE.

As discussed above, the DCI needs to be transmitted to every UE separately to indicate the CSI-ICM configuration which requires a large number of DCI transmission when there are a lot of UEs. To reduce this overhead, group-based CSI-ICM configuration can be used through DCI to enable multiple UEs measuring the interference channel. The UEs that have the same interference sources or share some resources when doing the CSI-ICM can be grouped and transmitted in one DCI containing the common information and the individual information to all the UEs in the group. The common information is the shared fields that are the same to all UEs in the group, in terms of group ID, CSI-ICM configuration, CSI-RS/ICM structure and etc. The individual information indicates the UE ID, UL resources to transmit the CSI-ICM feedback and all the other signaling cannot be shared among the UEs within the group which each UE has its unique information. An example of the configurable fields for group-base CSI-ICM configuration DCI scheme are listed in Table <NUM> below.

According to another embodiment, upon measuring the interference channel, the UE needs to feedback the interference channel estimation to NR node/TRP. This will be used in MU-MIMO scheduling. The interference channel feedback could be implicit, explicit or a combination of implicit and explicit feedbacks. For example, when the largest eigenvalue is less than a pre-defined threshold, only the implicit feedback is required, and otherwise, the UE needs to feedback the explicit channel measurement according to the eigenvalues greater than the threshold. The implicit feedback may contain information such as CQI, PMI or RI for the interference channel, and explicit feedback may be in the following forms: (i) The exact interference channel measurement; (ii) The eigenvectors of the interference channel according to the largest eigenvalues; and (iii) The covariance matrix of the interference channel.

To reduce the overhead of the explicit interference feedback, it could be quantized by a pre-defined codebook or transformed to a reduced-dimension form. The CSI-ICM feedback may be tolerant to a higher quantization error or a transforming error comparing to explicit CSI feedback.

A UE is configured by higher layer or NR DCI to periodically or aperiodically or semi-persistently send CSI-ICM feedback via NR PUCCH. A new NR PUCCH reporting type could be defined for CSI-ICM feedback. For periodic CSI-ICM feedback, the periodicity and relative offset are configured by higher layer signaling. For aperiodic or semi-persistent CSI-ICM, the resource to transmit CSI-ICM feedback is configured by NR DCI.

According to yet another embodiment, after receiving the CSI and CSI-ICM feedbacks, the NR node could be able to schedule MU-MIMO transmission. For the UE scheduled for MU-MIMO, beside the general transmission information such as resource allocation, Modulation and coding scheme, and HARQ process number, the NR DCI should also include the following information:.

According to another embodiment, procedures of interference channel measurement and interference cancellation are described. These include, for example:.

Based on the information from its NR DCI, the UE is able to cancel the interference transmitted to other co-scheduled UEs or from other beams/TRPs.

A call flow to portray the CSI-ICM procedure is illustrated in <FIG>.

According to a further aspect of the application, a semi-static RRC configuration of CSI measurement and the ppol of CSI-RS resource element for the UE, and dynamic signaling to schedule CSI measurement are described. Two methods for RRC based configuration of CSI-RS pooling resources.

Method <NUM>: UE-specific CSI-RS resources configuration, without configuration of a group of UEs sharing the same CSI-RS resource pool. The NR node (e.g., gNB) configures the UE with a set of K CSI-RS resources using dedicated RRC message (e.g., like RRCConnectionReconfiguration message or NR RRC equivalent). The UE uses the CSI-RS configuration to identify CSI-RS resources used for channel state measurement. The NR node may signal to the UE the exact CSI-RS to use from the configured set via MAC CE signaling or DCI signaling. The configuration set the NR node configures the UE with may include one or more of the parameters:.

Method <NUM>: UE-specific CSI-RS resources configuration, with configuration of a group of UEs sharing the same CSI-RS resource pool. In this embodiment, the NR node may limit CSI-RS configuration related signaling overhead by using group configuration. In addition to the parameters used in Method <NUM>, the configuration set the NR node configures the UE with may include one or more of the parameters:.

In one embodiment, the NR node may initially signals the CSI-RS configuration to the UE in dedicated UE RRC signaling as described in the embodiment above and then subsequently uses the group signaling to configure group of UEs with a common pool of CSI-RS resources.

According to another embodiment, a detailed design of CSI-RS Pooling DCI or MAC CE Signaling is described. Several signaling designs include: (i) CSI measurement command signaled in DCI; and (ii) CSI measurement command signaled in MAC CE.

MAC CE based signaling. In an embodiment, the following method can be used to signal CSI measurement command in MAC CE. Specifically, the NR node dynamically signals in MAC CE to the UE, transmission of CSI-RS preconfigured by RRC signaling. The indication of CSI-RS transmission in MAC CE may include the CSI-RS configuration index previously pre-configured in the UE (for e.g. via RRC signaling). The UE uses this index to locate the CSI-RS configuration information stored in its internal database. The UE may then perform measurement of the CSI-RS using the CSI-RS configuration parameters (e.g. antenna port count, resource information, CSI-RS transmission interval information, beam configuration) identified by the information (e.g. CSI-RS configuration index) received in the MAC CE.

In an exemplary embodiment, the MAC CE may carry in addition to the CSI-RS configuration index, the measurement time window. The measurement time windows may be pre-defined in the specification. It may be expressed in terms of an integer number of CSI-RS transmission time interval (e.g. CSI transmission periodicity time value), for e.g. <NUM>,<NUM>,<NUM>,<NUM> etc. For example, if the measurement time window is <NUM>, the UE measures CSI-RS over one CSI-RS transmission time interval and stop. Similarly, if the measurement time window is k, the UE measures CSI-RS over k CSI-RS transmission time intervals. In this embodiment, the NR node doesn't signals a MAC CE to the UE in order to terminate the CSI-RS measurement. The UE implicitly terminates the measurement using the received transmission time window.

In another embodiment, the NR node may explicitly signal to the UE in MAC CE, the termination (or de-activation) or a previously activated CSI-RS measurement. This may be the case, if the NR node didn't include in the prior CSR-RS measurement activation MAC CE, a measurement time window information. An example of CSI-RS measurement activation and deactivation MAC CE are depicted in <FIG> and <FIG>. The MAC CE may be defined over a fixed number n of octets. The transmission MAC CE may be identified by a MAC PDU subheader with Logical Channel Identifier (LCID) as defined later below.

Two examples of MAC CE are illustrated below. The CSI RS measurement Activation/Deactivation MAC control element with one octet is defined in <FIG>. It has a fixed size and consists of a single octet containing some RS-fields part and some TW field where TW encodes the measurement Time Window while the RS fields encode the activation or deactivation of CSI-RS measurement. Similarly, an example of Activation/Deactivation MAC control element of k octets with k=<NUM> as an example is defined in <FIG>. It has a fixed size and consists of a k octets containing RS-fields part and TW field part. The RS field is set to "<NUM>" to indicate that the CSI-RS configuration identified by configuration index i shall be activated. The RSi field is set to "<NUM>" to indicate that the CSI-RS configuration identified by configuration index i shall be deactivated.

The MAC CE as illustrated includes only one measurement time window TW. This means the measurement time window is common for all the CSI-RS configuration included in the MAC CE. However, the MAC CE may also be structure to include more than one TW. For example, assuming each of the CSI RS included in the MAC CE has different TW, then there will be as many TWs as RSs in the MCA CE.

<FIG> illustrates CSI-RS Measurement Activation/Deactivation MAC Control Element of one octet. <FIG> illustrates CSI-RS Measurement Activation/Deactivation MAC Control Element of k (k=<NUM>) octets.

The logical channel ID associated with the CSI-RS measurement activation/deactivation MAC CEs may be one of the existing reserved value of LTE downlink logical channels between the range <NUM> and <NUM> (binary coding). Alternatively, the LTE logical channel value ranges may be extended with new defined values assigned to CSI-RS measurement activation/deactivation MAC CE. The logical channel ID should uniquely identify the MAC CE. For e.g., the MAC CE in two figure above should have different logical channel IDs. The signallings described for MAC CE can be applicable to the DCI based signaling as well.

According to another embodiment, the following DCI based signaling methods can include: (i) CSI measurement command piggyback on DCI; (ii) Standalone CSI measurement command (sent on a separate DCI) for a specific UE; and (iii) Group-based DCI to schedule multiple UEs' CSI-RS measurement and feedback.

In Signaling Method <NUM>, CSI measurement command is piggybacked on another DCI using one or both of the following options:.

According to Option <NUM>, the CSI measurement command is signaled in a DCI that is used for scheduling of NR-PUSCH, so called UL grant DCI. It will carry the following information (explicitly or implicitly):.

<FIG> illustrates one or several NR-PUSCHs are scheduled for CSI measurement reporting.

<FIG> illustrates one NR-PUSCH and or several NR-PUCCHs are scheduled for CSI measurement reporting.

According to Option <NUM>, the CSI measurement command is signaled in a DCI that is used for scheduling of NR-PDSCH, which is the DL grant DCI. It will carry the following information (explicitly or implicitly) similar to Option <NUM>, and will include the following additional fields.

CSI measurement reporting, physical uplink channel and start time
H. The number of CSI measurement reports to be transmitted in the uplink can be explicitly signaled or implicitly interfered from the CSI measurement configuration.

The DCI can schedule several NR-PUCCHs in the subsequent sub-frames, each carry one complete CSI report (or part of it). The indices of these sub-frames will be signaled.

The NR-PUCCH index can be signaled implicitly from either the search space index of the uplink grant DCI or starting RB index of the RBs where the uplink grant DCI is transmitted.

CSI measurement report starting time: signaled as a timing offset from the current sub-frame, where the range of the offset value is zero to H sub-frames. The default value of the timing offset is zero. As shown in the figures below, when the offset is set to zero, the CSI measurement can be reported as early as the PUCCH at the end of current sub-frame following the NR-PDSCH scheduled by the DL grant DCI.

<FIG> illustrates several NR-PUCCHs are scheduled for CSI measurement reporting. The UE Procedures for Signaling method <NUM> (including options <NUM> and <NUM>) are described below as follows:.

According to another embodiment, a standalone CSI measurement command can be transmitted on a separate DCI can be used to active a CSI measurement for a UE. Such a standalone CSI measurement command DCI will carry the following information (explicitly or implicitly) as in Option <NUM> of signaling method <NUM>, and include the following additional fields:.

<FIG> illustrates several NR-PUCCHs are scheduled for CSI measurement reporting.

According to yet a further embodiment, UE Procedures for Signaling method <NUM> are as follows:.

Signaling Method <NUM> is described in accordance with a further embodiment. Here, a group-based CSI measurement DCI can be used to schedule CSI-RS measurement and feedback for multiple UEs. Group-based CSI measurement DCI can achieve reduced signaling overhead when these UEs have the same CSI reporting configuration and share the same CSI-RS resource pool configured by higher layer signalings. Such a group-based CSI measurement DCI will carry the following information (explicitly or implicitly) similar to those in Option <NUM> of signaling method <NUM>, except the following different fields:.

UE Procedures for Signaling method <NUM> are described below in accordance with a further embodiment as follows:.

The signallings described for DCI based signaling in this section can be applicable to the MAC CE based signaling as well.

It is understood that the functionality, steps, and configurations illustrated in <FIG> may be implemented in or produced by the form of software (i.e., computer-executable instructions) stored in a memory of, and executing on a processor of, a wireless device or other apparatus (e.g., a server, gateway, device, or other computer system), such as one of those illustrated in <FIG> and <FIG> described below.

Interfaces, such as Graphical User Interfaces (GUIs), can be used to assist user to control and/or configure functionalities related to reference signals and control channels in NR. <FIG> is a diagram that illustrates an interface <NUM> that allows a user to input and view parameters corresponding to reference signals and control channels in NR. It is to be understood that interface <NUM> can be produced using displays such as those shown in <FIG> and F described below.

The 3rd Generation Partnership Project (3GPP) develops technical standards for cellular telecommunications network technologies, including radio access, the core transport network, and service capabilities - including work on codecs, security, and quality of service. Recent radio access technology (RAT) standards include WCDMA (commonly referred as <NUM>), LTE (commonly referred as <NUM>), and LTE-Advanced standards. 3GPP has begun working on the standardization of next generation cellular technology, called New Radio (NR), which is also referred to as "<NUM>". 3GPP NR standards development is expected to include the definition of next generation radio access technology (new RAT), which is expected to include the provision of new flexible radio access below <NUM>, and the provision of new ultra-mobile broadband radio access above <NUM>. The flexible radio access is expected to consist of a new, non-backwards compatible radio access in new spectrum below <NUM>, and it is expected to include different operating modes that can be multiplexed together in the same spectrum to address a broad set of 3GPP NR use cases with diverging requirements. The ultra-mobile broadband is expected to include cmWave and mmWave spectrum that will provide the opportunity for ultra-mobile broadband access for, e.g., indoor applications and hotspots. In particular, the ultra-mobile broadband is expected to share a common design framework with the flexible radio access below <NUM>, with cmWave and mmWave specific design optimizations.

3GPP has identified a variety of use cases that NR is expected to support, resulting in a wide variety of user experience requirements for data rate, latency, and mobility. The use cases include the following general categories: enhanced mobile broadband (e.g., broadband access in dense areas, indoor ultra-high broadband access, broadband access in a crowd, <NUM>+ Mbps everywhere, ultra-low cost broadband access, mobile broadband in vehicles), critical communications, massive machine type communications, network operation (e.g., network slicing, routing, migration and interworking, energy savings), and enhanced vehicle-to-everything (eV2X) communications. Specific service and applications in these categories include, e.g., monitoring and sensor networks, device remote controlling, bi-directional remote controlling, personal cloud computing, video streaming, wireless cloud-based office, first responder connectivity, automotive ecall, disaster alerts, real-time gaming, multi-person video calls, autonomous driving, augmented reality, tactile internet, and virtual reality to name a few. All of these use cases and others are contemplated herein.

<FIG> illustrates one embodiment of an example communications system <NUM> in which the methods and apparatuses described and claimed herein may be embodied. As shown, the example communications system <NUM> may include wireless transmit/receive units (WTRUs) 102a, 102b, 102c, and/or 102d (which generally or collectively may be referred to as WTRU <NUM>), a radio access network (RAN) <NUM>/<NUM>/<NUM>/103b/104b/105b, a core network <NUM>/<NUM>/<NUM>, a public switched telephone network (PSTN) <NUM>, the Internet <NUM>, and other networks <NUM>, though it will be appreciated that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and/or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of apparatus or device configured to operate and/or communicate in a wireless environment. Although each WTRU 102a, 102b, 102c, 102d is depicted in <FIG> as a hand-held wireless communications apparatus, it is understood that with the wide variety of use cases contemplated for <NUM> wireless communications, each WTRU may comprise or be embodied in any type of apparatus or device configured to transmit and/or receive wireless signals, including, by way of example only, user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, a cellular telephone, a personal digital assistant (PDA), a smartphone, a laptop, a tablet, a netbook, a notebook computer, a personal computer, a wireless sensor, consumer electronics, a wearable device such as a smart watch or smart clothing, a medical or eHealth device, a robot, industrial equipment, a drone, a vehicle such as a car, truck, train, or airplane, and the like.

The communications system <NUM> may also include a base station 114a and a base station 114b. Base stations 114a may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c to facilitate access to one or more communication networks, such as the core network <NUM>/<NUM>/<NUM>, the Internet <NUM>, and/or the other networks <NUM>. Base stations 114b may be any type of device configured to wiredly and/or wirelessly interface with at least one of the RRHs (remote radio heads) 118a, 118b and/or TRPs (transmission and reception points) 119a, 119b to facilitate access to one or more communication networks, such as the core network <NUM>/<NUM>/<NUM>, the Internet <NUM>, and/or the other networks <NUM>. RRHs 118a, 118b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102c, to facilitate access to one or more communication networks, such as the core network <NUM>/<NUM>/<NUM>, the Internet <NUM>, and/or the other networks <NUM>. TRPs 119a, 119b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102d, to facilitate access to one or more communication networks, such as the core network <NUM>/<NUM>/<NUM>, the Internet <NUM>, and/or the other networks <NUM>. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node-B, an eNode B, a Home Node B, a Home eNode B, a site controller, an access point (AP), a wireless router, and the like.

The base station 114a may be part of the RAN <NUM>/<NUM>/<NUM>, which may also include other base stations and/or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), relay nodes, etc. The base station 114b may be part of the RAN 103b/104b/105b, which may also include other base stations and/or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), relay nodes, etc. The base station 114a may be configured to transmit and/or receive wireless signals within a particular geographic region, which may be referred to as a cell (not shown). The base station 114b may be configured to transmit and/or receive wired and/or wireless signals within a particular geographic region, which may be referred to as a cell (not shown). Thus, in an embodiment, the base station 114a may include three transceivers, e.g., one for each sector of the cell. In an embodiment, the base station 114a may employ multiple-input multiple output (MIMO) technology and, therefore, may utilize multiple transceivers for each sector of the cell.

The base stations 114a may communicate with one or more of the WTRUs 102a, 102b, 102c over an air interface <NUM>/<NUM>/<NUM>, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, cmWave, mmWave, etc.). The air interface <NUM>/<NUM>/<NUM> may be established using any suitable radio access technology (RAT).

The base stations 114b may communicate with one or more of the RRHs 118a, 118b and/or TRPs 119a, 119b over a wired or air interface 115b/116b/117b, which may be any suitable wired (e.g., cable, optical fiber, etc.) or wireless communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, cmWave, mmWave, etc.). The air interface 115b/116b/117b may be established using any suitable radio access technology (RAT).

The RRHs 118a, 118b and/or TRPs 119a, 119b may communicate with one or more of the WTRUs 102c, 102d over an air interface 115c/116c/117c, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, cmWave, mmWave, etc.). The air interface 115c/116c/117c may be established using any suitable radio access technology (RAT).

For example, the base station 114a in the RAN <NUM>/<NUM>/<NUM> and the WTRUs 102a, 102b, 102c, or RRHs 118a, 118b and TRPs 119a, 119b in the RAN 103b/104b/105b and the WTRUs 102c, 102d, may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface <NUM>/<NUM>/<NUM> or 115c/116c/117c respectively using wideband CDMA (WCDMA).

In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c, or RRHs 118a, 118b and TRPs 119a, 119b in the RAN 103b/104b/105b and the WTRUs 102c, 102d, may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface <NUM>/<NUM>/<NUM> or 115c/116c/117c respectively using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A). In the future, the air interface <NUM>/<NUM>/<NUM> may implement 3GPP NR technology.

In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c, or RRHs 118a, 118b and TRPs 119a, 119b in the RAN 103b/104b/105b and the WTRUs 102c, 102d, may implement radio technologies such as IEEE <NUM> (e.g., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard <NUM> (IS-<NUM>), Interim Standard <NUM> (IS-<NUM>), Interim Standard <NUM> (IS-<NUM>), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and the like.

The base station 114c in <FIG> may be a wireless router, Home Node B, Home eNode B, or access point, for example, and may utilize any suitable RAT for facilitating wireless connectivity in a localized area, such as a place of business, a home, a vehicle, a campus, and the like. In an embodiment, the base station 114c and the WTRUs 102e, may implement a radio technology such as IEEE <NUM> to establish a wireless local area network (WLAN). In an embodiment, the base station 114c and the WTRUs 102d, may implement a radio technology such as IEEE <NUM> to establish a wireless personal area network (WPAN). In yet an embodiment, the base station 114c and the WTRUs 102e, may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, etc.) to establish a picocell or femtocell. As shown in Figure 4A, the base station 114b may have a direct connection to the Internet <NUM>. Thus, the base station 114c may not be required to access the Internet <NUM> via the core network <NUM>/<NUM>/<NUM>.

The RAN <NUM>/<NUM>/<NUM> and/or RAN 103b/104b/105b may be in communication with the core network <NUM>/<NUM>/<NUM>, which may be any type of network configured to provide voice, data, applications, and/or voice over internet protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. For example, the core network <NUM>/<NUM>/<NUM> may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, video distribution, etc., and/or perform high-level security functions, such as user authentication.

Although not shown in <FIG>, it will be appreciated that the RAN <NUM>/<NUM>/<NUM> and/or RAN 103b/104b/105b and/or the core network <NUM>/<NUM>/<NUM> may be in direct or indirect communication with other RANs that employ the same RAT as the RAN <NUM>/<NUM>/<NUM> and/or RAN 103b/104b/105b or a different RAT. For example, in addition to being connected to the RAN <NUM>/<NUM>/<NUM> and/or RAN 103b/104b/105b, which may be utilizing an E-UTRA radio technology, the core network <NUM>/<NUM>/<NUM> may also be in communication with another RAN (not shown) employing a GSM radio technology.

The core network <NUM>/<NUM>/<NUM> may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d, 102e to access the PSTN <NUM>, the Internet <NUM>, and/or other networks <NUM>. For example, the networks <NUM> may include another core network connected to one or more RANs, which may employ the same RAT as the RAN <NUM>/<NUM>/<NUM> and/or RAN 103b/104b/<NUM> or a different RAT.

Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system <NUM> may include multi-mode capabilities, e.g., the WTRUs 102a, 102b, 102c, 102d, and 102e may include multiple transceivers for communicating with different wireless networks over different wireless links. For example, the WTRU 102e shown in Figure 4A may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114c, which may employ an IEEE <NUM> radio technology.

<FIG> is a block diagram of an example apparatus or device configured for wireless communications in accordance with the embodiments illustrated herein, such as for example, a WTRU <NUM>. As shown in <FIG>, the example WTRU <NUM> may include a processor <NUM>, a transceiver <NUM>, a transmit/receive element <NUM>, a speaker/microphone <NUM>, a keypad <NUM>, a display/touchpad/indicators <NUM>, non-removable memory <NUM>, removable memory <NUM>, a power source <NUM>, a global positioning system (GPS) chipset <NUM>, and other peripherals <NUM>. Also, embodiments contemplate that the base stations 114a and 114b, and/or the nodes that base stations 114a and 114b may represent, such as but not limited to transceiver station (BTS), a Node-B, a site controller, an access point (AP), a home node-B, an evolved home node-B (eNodeB), a home evolved node-B (HeNB), a home evolved node-B gateway, and proxy nodes, among others, may include some or all of the elements depicted in <FIG> and described herein.

The transmit/receive element <NUM> may be configured to transmit signals to, or receive signals from, a base station (e.g., the base station 114a) over the air interface <NUM>/<NUM>/<NUM>. For example, in an embodiment, the transmit/receive element <NUM> may be an antenna configured to transmit and/or receive RF signals. In an embodiment, the transmit/receive Although not shown in <FIG>, it will be appreciated that the RAN <NUM>/<NUM>/<NUM> and/or the core network <NUM>/<NUM>/<NUM> may be in direct or indirect communication with other RANs that employ the same RAT as the RAN <NUM>/<NUM>/<NUM> or a different RAT. For example, in addition to being connected to the RAN <NUM>/<NUM>/<NUM>, which may be utilizing an E-UTRA radio technology, the core network <NUM>/<NUM>/<NUM> may also be in communication with another RAN (not shown) employing a GSM radio technology.

The core network <NUM>/<NUM>/<NUM> may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN <NUM>, the Internet <NUM>, and/or other networks <NUM>. For example, the networks <NUM> may include another core network connected to one or more RANs, which may employ the same RAT as the RAN <NUM>/<NUM>/<NUM> or a different RAT.

Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system <NUM> may include multi-mode capabilities, e.g., the WTRUs 102a, 102b, 102c, and 102d may include multiple transceivers for communicating with different wireless networks over different wireless links.

The transmit/receive element <NUM> may be configured to transmit signals to, or receive signals from, a base station (e.g., the base station 114a) over the air interface <NUM>/<NUM>/<NUM>. For example, in an embodiment, the transmit/receive element <NUM> may be an antenna configured to transmit and/or receive RF signals. In yet an embodiment, the transmit/receive element <NUM> may be configured to transmit and receive both RF and light signals.

Thus, in an embodiment, the WTRU <NUM> may include two or more transmit/receive elements <NUM> (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface <NUM>/<NUM>/<NUM>.

The processor <NUM> of the WTRU <NUM> may be coupled to, and may receive user input data from, the speaker/microphone <NUM>, the keypad <NUM>, and/or the display/touchpad/indicators <NUM> (e.g., a liquid crystal display (LCD) display unit or organic light-emitting diode (OLED) display unit). The processor <NUM> may also output user data to the speaker/microphone <NUM>, the keypad <NUM>, and/or the display/touchpad/indicators <NUM>. In an embodiment, the processor <NUM> may access information from, and store data in, memory that is not physically located on the WTRU <NUM>, such as on a server or a home computer (not shown).

For example, the power source <NUM> may include one or more dry cell batteries, solar cells, fuel cells, and the like.

For example, the peripherals <NUM> may include various sensors such as an accelerometer, biometrics (e.g., finger print) sensors, an e-compass, a satellite transceiver, a digital camera (for photographs or video), a universal serial bus (USB) port or other interconnect interfaces, a vibration device, a television transceiver, a hands free headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, and the like.

The WTRU <NUM> may be embodied in other apparatuses or devices, such as a sensor, consumer electronics, a wearable device such as a smart watch or smart clothing, a medical or eHealth device, a robot, industrial equipment, a drone, a vehicle such as a car, truck, train, or airplane. The WTRU <NUM> may connect to other components, modules, or systems of such apparatuses or devices via one or more interconnect interfaces, such as an interconnect interface that may comprise one of the peripherals <NUM>.

As noted above, the RAN <NUM> may employ a UTRA radio technology to communicate with the WTRUs 102a, 102b, and 102c over the air interface <NUM>. As shown in <FIG>, the RAN <NUM> may include Node-Bs 140a, 140b, 140c, which may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface <NUM>. The Node-Bs 140a, 140b, 140c may each be associated with a particular cell (not shown) within the RAN <NUM>. The RAN <NUM> may also include RNCs 142a, 142b. It will be appreciated that the RAN <NUM> may include any number of Node-Bs and RNCs while remaining consistent with an embodiment.

As shown in Figure 4C, the Node-Bs 140a, 140b may be in communication with the RNC 142a. Additionally, the Node-B 140c may be in communication with the RNC 142b. The Node-Bs 140a, 140b, 140c may communicate with the respective RNCs 142a, 142b via an Iub interface. The RNCs 142a, 142b may be in communication with one another via an Iur interface. Each of the RNCs 142a, 142b may be configured to control the respective Node-Bs 140a, 140b, 140c to which it is connected. In addition, each of the RNCs 142a, 142b may be configured to carry out or support other functionality, such as outer loop power control, load control, admission control, packet scheduling, handover control, macro-diversity, security functions, data encryption, and the like.

The core network <NUM> shown in Figure 4C may include a media gateway (MGW) <NUM>, a mobile switching center (MSC) <NUM>, a serving GPRS support node (SGSN) <NUM>, and/or a gateway GPRS support node (GGSN) <NUM>.

As noted above, the RAN <NUM> may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, and 102c over the air interface <NUM>.

In an embodiment, the eNode-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the eNode-B 160a, for example, may use multiple antennas to transmit wireless signals to, and receive wireless signals from, the WTRU 102a.

Each of the eNode-Bs 160a, 160b, and 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the uplink and/or downlink, and the like. As shown in Figure 4D, the eNode-Bs 160a, 160b, 160c may communicate with one another over an X2 interface.

The core network <NUM> shown in Figure 4D may include a mobility management gateway (MME) <NUM>, a serving gateway <NUM>, and a packet data network (PDN) gateway <NUM>.

The MME <NUM> may be connected to each of the eNode-Bs 160a, 160b, and 160c in the RAN <NUM> via an S1 interface and may serve as a control node. The MME <NUM> may also provide a control plane function for switching between the RAN <NUM> and other RANs (not shown) that employ other radio technologies, such as GSM or WCDMA.

The serving gateway <NUM> may be connected to each of the eNode-Bs 160a, 160b, and 160c in the RAN <NUM> via the S1 interface. The serving gateway <NUM> may generally route and forward user data packets to/from the WTRUs 102a, 102b, 102c. The serving gateway <NUM> may also perform other functions, such as anchoring user planes during inter-eNode B handovers, triggering paging when downlink data is available for the WTRUs 102a, 102b, 102c, managing and storing contexts of the WTRUs 102a, 102b, 102c, and the like.

The RAN <NUM> may be an access service network (ASN) that employs IEEE <NUM> radio technology to communicate with the WTRUs 102a, 102b, and 102c over the air interface <NUM>. As will be further discussed below, the communication links between the different functional entities of the WTRUs 102a, 102b, 102c, the RAN <NUM>, and the core network <NUM> may be defined as reference points.

As shown in <FIG>, the RAN <NUM> may include base stations 180a, 180b, 180c, and an ASN gateway <NUM>, though it will be appreciated that the RAN <NUM> may include any number of base stations and ASN gateways while remaining consistent with an embodiment. The base stations 180a, 180b, 180c may each be associated with a particular cell in the RAN <NUM> and may include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface <NUM>. In an embodiment, the base stations 180a, 180b, 180c may implement MIMO technology. Thus, the base station 180a, for example, may use multiple antennas to transmit wireless signals to, and receive wireless signals from, the WTRU 102a. The base stations 180a, 180b, 180c may also provide mobility management functions, such as handoff triggering, tunnel establishment, radio resource management, traffic classification, quality of service (QoS) policy enforcement, and the like. The ASN gateway <NUM> may serve as a traffic aggregation point and may be responsible for paging, caching of subscriber profiles, routing to the core network <NUM>, and the like.

The air interface <NUM> between the WTRUs 102a, 102b, 102c and the RAN <NUM> may be defined as an R1 reference point that implements the IEEE <NUM> specification. In addition, each of the WTRUs 102a, 102b, and 102c may establish a logical interface (not shown) with the core network <NUM>. The logical interface between the WTRUs 102a, 102b, 102c and the core network <NUM> may be defined as an R2 reference point, which may be used for authentication, authorization, IP host configuration management, and/or mobility management.

The communication link between each of the base stations 180a, 180b, and 180c may be defined as an R8 reference point that includes protocols for facilitating WTRU handovers and the transfer of data between base stations. The communication link between the base stations 180a, 180b, 180c and the ASN gateway <NUM> may be defined as an R6 reference point. The R6 reference point may include protocols for facilitating mobility management based on mobility events associated with each of the WTRUs 102a, 102b, 102c.

The MIP-HA may be responsible for IP address management, and may enable the WTRUs 102a, 102b, and 102c to roam between different ASNs and/or different core networks. The MIP-HA <NUM> may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet <NUM>, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The AAA server <NUM> may be responsible for user authentication and for supporting user services. The gateway <NUM> may facilitate interworking with other networks. For example, the gateway <NUM> may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN <NUM>, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. In addition, the gateway <NUM> may provide the WTRUs 102a, 102b, 102c with access to the networks <NUM>, which may include other wired or wireless networks that are owned and/or operated by other service providers.

The core network entities described herein and illustrated in <FIG>, <FIG>, <FIG>, and <FIG> are identified by the names given to those entities in certain existing 3GPP specifications, but it is understood that in the future those entities and functionalities may be identified by other names and certain entities or functions may be combined in future specifications published by 3GPP, including future 3GPP NR specifications. Thus, the particular network entities and functionalities described and illustrated in <FIG>, <FIG>, <FIG>, <FIG>, and <FIG> are provided by way of example only, and it is understood that the subject matter disclosed and claimed herein may be embodied or implemented in any similar communication system, whether presently defined or defined in the future.

<FIG> is a block diagram of an exemplary computing system <NUM> in which one or more apparatuses of the communications networks illustrated in <FIG>, <FIG>, <FIG> and <FIG> may be embodied, such as certain nodes or functional entities in the RAN <NUM>/<NUM>/<NUM>, Core Network <NUM>/<NUM>/<NUM>, PSTN <NUM>, Internet <NUM>, or Other Networks <NUM>. Computing system <NUM> may comprise a computer or server and may be controlled primarily by computer readable instructions, which may be in the form of software, wherever, or by whatever means such software is stored or accessed. Such computer readable instructions may be executed within a processor <NUM>, to cause computing system <NUM> to do work. The processor <NUM> may perform signal coding, data processing, power control, input/output processing, and/or any other functionality that enables the computing system <NUM> to operate in a communications network. Coprocessor <NUM> is an optional processor, distinct from main processor <NUM>, that may perform additional functions or assist processor <NUM>. Processor <NUM> and/or coprocessor <NUM> may receive, generate, and process data related to the methods and apparatuses disclosed herein.

In operation, processor <NUM> fetches, decodes, and executes instructions, and transfers information to and from other resources via the computing system's main data-transfer path, system bus <NUM>. Such a system bus connects the components in computing system <NUM> and defines the medium for data exchange. System bus <NUM> typically includes data lines for sending data, address lines for sending addresses, and control lines for sending interrupts and for operating the system bus. An example of such a system bus <NUM> is the PCI (Peripheral Component Interconnect) bus.

Memories coupled to system bus <NUM> include random access memory (RAM) <NUM> and read only memory (ROM) <NUM>. Such memories include circuitry that allows information to be stored and retrieved. ROMs <NUM> generally contain stored data that cannot easily be modified. Data stored in RAM <NUM> can be read or changed by processor <NUM> or other hardware devices. Access to RAM <NUM> and/or ROM <NUM> may be controlled by memory controller <NUM>. Memory controller <NUM> may provide an address translation function that translates virtual addresses into physical addresses as instructions are executed. Memory controller <NUM> may also provide a memory protection function that isolates processes within the system and isolates system processes from user processes. Thus, a program running in a first mode can access only memory mapped by its own process virtual address space; it cannot access memory within another process's virtual address space unless memory sharing between the processes has been set up.

In addition, computing system <NUM> may contain peripherals controller <NUM> responsible for communicating instructions from processor <NUM> to peripherals, such as printer <NUM>, keyboard <NUM>, mouse <NUM>, and disk drive <NUM>.

Display <NUM>, which is controlled by display controller <NUM>, is used to display visual output generated by computing system <NUM>. Such visual output may include text, graphics, animated graphics, and video. The visual output may be provided in the form of a graphical user interface (GUI). Display <NUM> may be implemented with a CRT-based video display, an LCD-based flat-panel display, gas plasma-based flat-panel display, or a touch-panel. Display controller <NUM> includes electronic components required to generate a video signal that is sent to display <NUM>.

Further, computing system <NUM> may contain communication circuitry, such as for example a network adapter <NUM>, that may be used to connect computing system <NUM> to an external communications network, such as the RAN <NUM>/<NUM>/<NUM>, Core Network <NUM>/<NUM>/<NUM>, PSTN <NUM>, Internet <NUM>, or Other Networks <NUM> of <FIG>, <FIG>, <FIG>, <FIG>, and <FIG>, to enable the computing system <NUM> to communicate with other nodes or functional entities of those networks. The communication circuitry, alone or in combination with the processor <NUM>, may be used to perform the transmitting and receiving steps of certain apparatuses, nodes, or functional entities described herein.

Claim 1:
A method, performed by a New Radio, NR, node (<NUM>), for configuring wireless transmit/receive units, WTRUs, (<NUM>) comprising:
configuring a set of 'K' channel state information interference channel measurement, CSI-ICM resources for a group of WTRUs;
indicating, to the WTRUs in the group, the 'K' CSI-ICM resources via radio resource control, RRC, signalling;
transmitting downlink control information which signals a number 'N' of the K CSI-ICM resources to at least two WTRUs in the group, the at least two WTRUs in the group having the same interference sources, where N is at least one and is less than K, and wherein N corresponds to a number of the interference sources;
receiving, from the at least two WTRUs in the group, feedback of an interference measurement based on the indicated N CSI-ICM resources;
scheduling a MU-MIMO transmission for the at least two WTRUs based on the feedback and sending an indication of the scheduled MU-MIMO transmission to the at least two WTRUs; and
determining, based on the scheduled MU-MIMO transmission,
that a first of the at least two WTRUs in the group has cancelled interference transmitted from the first of the at least two WTRUs to a second of the at least two WTRUs in the group.