WO2025194330A1

WO2025194330A1 - Intra-physical downlink shared channel interference measurement resources for multiple user multiple-input-multiple-output pairing and modulation and coding scheme determination

Info

Publication number: WO2025194330A1
Application number: PCT/CN2024/082372
Authority: WO
Inventors: Chao Wei; Jing Sun; Yu Zhang; Jing Jiang
Original assignee: Qualcomm Inc
Current assignee: Qualcomm Inc
Priority date: 2024-03-19
Filing date: 2024-03-19
Publication date: 2025-09-25
Anticipated expiration: 2026-09-19

Abstract

Certain aspects of the present disclosure provide techniques for multiple user (MU) -multiple-input-multiple-output (MIMO) pairing and modulation and coding scheme (MCS) determination. A method generally includes receiving a downlink control information that: schedules a first downlink communication comprising a first zero power channel state information interference measurement (ZP CSI-IM) resource associated with a candidate co-scheduled user equipment (UE) and contained within a first plurality of resources allocated for a first downlink data channel and triggers an interference measurement for the first ZP CSI-IM resource; receiving the first downlink communication; performing an interference measurement based at least in part on the first ZP CSI-IM resource; and sending a multiple user (MU) channel quality indicator (CQI) based at least in part on the interference measurement.

Description

INTRA-PHYSICAL DOWNLINK SHARED CHANNEL INTERFERENCE MEASUREMENT RESOURCES FOR MULTIPLE USER MULTIPLE-INPUT-MULTIPLE-OUTPUT PAIRING AND MODULATION AND CODING SCHEME DETERMINATION

INTRODUCTION

Field of the Disclosure

Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for multiple user (MU) -multiple-input-multiple-output (MIMO) pairing and modulation and coding scheme (MCS) determination.

Description of Related Art

Wireless communications systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcasts, or other similar types of services. These wireless communications systems may employ multiple-access technologies capable of supporting communications with multiple users by sharing available wireless communications system resources with those users.

Although wireless communications systems have made great technological advancements over many years, challenges still exist. For example, complex and dynamic environments can still attenuate or block signals between wireless transmitters and wireless receivers. Accordingly, there is a continuous desire to improve the technical performance of wireless communications systems, including, for example: improving speed and data carrying capacity of communications, improving efficiency of the use of shared communications mediums, reducing power used by transmitters and receivers while performing communications, improving reliability of wireless communications, avoiding redundant transmissions and/or receptions and related processing, improving the coverage area of wireless communications, increasing the number and types of devices that can access wireless communications systems, increasing the ability for different types of devices to intercommunicate, increasing the number and type of wireless communications mediums available for use, and the like. Consequently, there exists a need for further improvements in wireless communications systems to overcome the aforementioned technical challenges and others.

SUMMARY

One aspect provides a method for wireless communications by an apparatus. The method includes receiving a downlink control information that: schedules a first downlink communication comprising a first zero power channel state information interference measurement (ZP CSI-IM) resource associated with a candidate co-scheduled user equipment (UE) and contained within a first plurality of resources allocated for a first downlink data channel and triggers an interference measurement for the first ZP CSI-IM resource; receiving the first downlink communication; performing an interference measurement based at least in part on the first ZP CSI-IM resource; and sending a multiple user (MU) channel quality indicator (CQI) based at least in part on the interference measurement.

Another aspect provides a method for wireless communications by an apparatus. The method includes sending a DCI that: schedules a first downlink communication for a UE, the first downlink communication comprising a first ZP CSI-IM resource associated with a candidate co-scheduled UE and contained within a first plurality of resources allocated for a first downlink data channel, and triggers an interference measurement for the first ZP CSI-IM resource; and sending the first downlink communication; receiving an MU CQI based at least in part on the first downlink communication.

Other aspects provide: one or more apparatuses operable, configured, or otherwise adapted to perform any portion of any method described herein (e.g., such that performance may be by only one apparatus or in a distributed fashion across multiple apparatuses) ; one or more non-transitory, computer-readable media comprising instructions that, when executed by one or more processors of one or more apparatuses, cause the one or more apparatuses to perform any portion of any method described herein (e.g., such that instructions may be included in only one computer-readable medium or in a distributed fashion across multiple computer-readable media, such that instructions may be executed by only one processor or by multiple processors in a distributed fashion, such that each apparatus of the one or more apparatuses may include one processor or multiple processors, and/or such that performance may be by only one apparatus or in a distributed fashion across multiple apparatuses) ; one or more computer program products embodied on one or more computer-readable storage media comprising code for performing any portion of any method described herein (e.g., such that code may be stored in only one computer-readable medium or across computer-readable media in a distributed fashion) ; and/or one or more apparatuses comprising one or more means for performing any portion of any method described herein (e.g., such that performance would be by only one apparatus or by multiple apparatuses in a distributed fashion) . By way of example, an apparatus may comprise a processing system, a device with a processing system, or processing systems cooperating over one or more networks. An apparatus may comprise one or more memories; and one or more processors configured to cause the apparatus to perform any portion of any method described herein. In some examples, one or more of the processors may be preconfigured to perform various functions or operations described herein without requiring configuration by software.

The following description and the appended figures set forth certain features for purposes of illustration.

BRIEF DESCRIPTION OF DRAWINGS

The appended figures depict certain features of the various aspects described herein and are not to be considered limiting of the scope of this disclosure.

FIG. 1 depicts an example wireless communications network.

FIG. 2 depicts an example disaggregated base station architecture.

FIG. 3 depicts aspects of an example base station and an example user equipment.

FIGS. 4A, 4B, 4C, and 4D depict various example aspects of data structures for a wireless communications network.

FIG. 5A depicts an example single user multi-input-multiple-output scheme.

FIG. 5B depicts an example multiple user multi-input-multiple-output scheme.

FIGS. 6A-6B depict example use of non-zero power channel state information reference signals for interference measurement.

FIG. 6C depicts example use of zero power channel state information interference measurement resources for interference measurement.

FIG. 7 depicts example use of zero power channel state information interference measurement resources for channel state information reporting.

FIG. 8 depicts a process flow for communications in a network between a network entity and a user equipment to communicate a downlink data transmission, with self-contained zero power channel state information interference measurement resources, for the evaluation of candidate multiple user MU pairing (s) for multiple user multiple-input-multiple-output communications.

FIG. 9 depicts an example downlink data transmission with self-contained zero power channel state information interference measurement resources corresponding to multiple candidate co-scheduled UEs.

FIG. 10 depicts a method for wireless communications.

FIG. 11 depicts another method for wireless communications.

FIG. 12 depicts aspects of an example communications device.

FIG. 13 depicts aspects of an example communications device.

DETAILED DESCRIPTION

Aspects of the present disclosure provide apparatuses, methods, processing systems, and computer-readable mediums for introducing zero power (ZP) channel state information interference measurement (CSI-IM) resources in a downlink data transmission for (1) the evaluation of candidate multiple user (MU) pairing (s) for MU multiple-input-multiple-output (MIMO) communications and/or (2) modulation and coding scheme (MCS) determination.

MIMO is an antenna technology for wireless communication in which multiple antennas are used at both transmitter and receiver ends of a communication system. By leveraging multiple antennas, MIMO may deliver multiple data streams simultaneously, thereby effectively improving reliability by having more redundant signals. MIMO technology may also help to improve network capacity. For example, the simultaneous transmission and reception of multiple data streams may allow for more data to be communicated at once, thereby contributing to an increase in network capacity.

There exists two primary types of MIMO: single user (SU) -MIMO and multiple user (MU) -MIMO. In SU-MIMO, all data streams transmitted may be intended for a single user. Alternatively, in MU-MIMO, two or more data streams may be transmitted to at least two different users. For instance, a network entity may transmit multiple data streams to at least two user equipments (UEs) on the same time-frequency resources using different spatial precoders.

A network entity is generally responsible for determining an MU pairing for MU-MIMO communications. As used herein, an MU pairing may include two or more UEs with which a network entity may simultaneously communicate over the same or overlapping time-frequency resources. For example, a network entity may attempt to determine an MU pairing that achieves the greatest system capacity and the least amount of channel interference. Specifically, co-channel interference (also referred to as “MU interference” ) may occur when multiple users are sharing the same time-frequency resources for MU-MIMO communication.

CSI reporting (e.g., including channel state feedback based on channel and interference measurements at a UE) may be used to assist a network entity with MU pairing for MU-MIMO communication. For example, a network entity may determine an initial MU pairing of UEs based on SU CSI reported by each UE, where the SU CSI reported by each UE provides information about a communications channel between the network entity and the respective UE, assuming no interference.

To determine MCS (s) to use for communication with the MU paired UEs (e.g., UEs co-scheduled on the same or overlapping time-frequency resources for MIMO communication) (e.g., to determine one MCS per co-scheduled UE) , the network entity may transmit precoded non-zero power (NZP) channel state information reference signals (CSI-RSs) triggering interference measurements by one or more of the UEs. The interference measurements may be used to determine channel quality, based on co-channel interference, that may be reported to the network entity as MU channel quality indicator (s) (MU CQI (s) ) . Based on the reported MU CQI (s) (e.g., as part of MU CSI reporting) , the network entity may determine MCS (s) to use for downlink communication with the MU paired UEs.

For example, an MU pairing, based on SU CSI reporting, may include three UEs, such that three UEs are co-scheduled for MIMO communication. To determine an MCS to use for downlink communication with a first UE of the three UEs, the network entity may transmit NZP CSI-RS (s) precoded using a precoder determined for the first UE. The second UE and the third UE may measure interference from the first UE on the precoded NZP CSI-RS (s) . The second UE and the third UE may each determine an MU CQI based on the measured interference and report these MU CQIs to the network entity, as part of MU CSI reporting. The same process may be repeated to determine and report MU CQIs based on NZP CSI-RS (s) precoded using a precoder determined for the second UE and a precoder determined for the third UE. As such, based on some methods for MU pairing and MCS determination, the network entity may transmit multiple precoded NZP-CSI-RS corresponding to different MU paired UEs, and the MU paired UEs may report multiple MU CQIs.

A technical problem associated with these methods for MU pairing and MCS determination involves the determination of MU pairing based on SU CSI reporting alone. For example, channel quality information included in SU CSI reports may not consider interference caused by other UEs in an MU-MIMO system. Thus, an MU pairing determined by a network entity based on this information alone may not be a “best” MU pairing for MIMO communication that achieves maximum network capacity and communication reliability, as well as minimum co-channel interference. Further, because a UE may only report MU CSI for co-scheduled UEs, interference from other UEs that may be candidates for MU pairing may be unknown. Understanding the interference caused by each candidate UE may be effectively used for minimizing interference when determining a MU pairing for MU-MIMO communication.

Another technical problem associated with some methods for MU pairing and MCS determination involves the transmission of SU and MU CSI information. For example, transmitting and receiving SU CSI information for initial MU pairing, as well as transmitting and receiving MU CSI information for each MU paired UE for determining MCSs, may incur a significant amount of network overhead, latency, and/or power use. Further, in some cases, the reported MU CSI information may indicate interference between the MU paired UEs such that the network entity determines to change the MU pairing (e.g., remove one or more MU paired UEs from the existing MU pairing and/or add one or more other UEs to the existing MU pairing) . Changing the existing pairing may cause (or require) the network entity to again receive MU CSI information for the updated MU pairing, thereby further increasing network resource usage, latency, and/or power use.

To overcome the aforementioned technical problems associated with methods for MU pairing and MCS determination and improve upon the state of the art, aspects described herein provide techniques for utilizing ZP CSI-IM resources in downlink data transmissions. For example, resources allocated for transmitting downlink data to a UE may include one or more ZP CSI-IM resources (e.g., self-contained ZP CSI-IM resources, such as contained within a plurality of resources allocated for transmitting the downlink data) . The ZP CSI-IM resource (s) may be associated with one or more UEs that may be paired with the UE (e.g., the UE receiving the downlink data with the self-contained CSI-IM resources) for MU-MIMO communications (also referred to herein as “candidate co-scheduled UEs” ) . Inclusion of the ZP CSI-IM resource (s) in the downlink data transmission, from a network entity, may trigger the UE receiving the transmission to perform one or more interference measurements to estimate interference from the candidate co-scheduled UE (s) that may be potentially co-scheduled with the UE during MU-MIMO communications. The UE may report CQI (s) , to the network entity, based on the interference measurement (s) , and the network entity may use the reported CQI (s) for MU pairing, MU pairing switching, and/or MCS determinations.

Accordingly, introducing ZP CSI-IM resources in a downlink data transmission beneficially enables a network entity to determine an MU pairing for MU-MIMO communications that achieves sufficient network capacity and/or communication reliability, while also reducing interference. For example, the network entity may evaluate the interference that may be caused by various candidate MU pairings, each of the MU pairing candidates involving at least the UE receiving the downlink data transmission, and based on this interference evaluation determine a “best” MU pairing for MU-MIMO communication. Identifying MU pairings based on interference measurement (s) estimated for different candidate co-scheduled UEs, instead of based on SU CSI reporting alone without any interference information, may allow the network entity to identify a better pairing for such communication (e.g., an MU pairing that at least reduces interference) . Further, the identification of an MU pairing at the outset (e.g., when determining a first MU pairing) that results in reduced interference, and accordingly sufficient network capacity and/or communication reliability, may reduce further MU pair switching (e.g., to have a better MU pairing) . Any change to a UE pairing may cause (or require) the exchange of updated CSI for MU-MIMO communications, thereby incurring an additional amount of network overhead, latency, and/or power use (e.g., at the network entity and a UE for transmitting and receiving such information) . Thus, by efficiently identifying a “best” MU pairing, network overhead and power consumption may be reduced, and in some cases, the benefits of MU-MIMO communications may be realized more quickly.

Additionally, by including ZP CSI-IM resource (s) in a downlink data transmission, a network entity may be able to “test” the pairing (e.g., the spatial division multiplexing) of candidate co-scheduled UEs with the UE receiving the downlink data transmission for MU-MIMO communications prior to establishing an MU pairing. This is different than some methods, described above, where an MU pairing is created based on SU CSI reporting and then MU CSI reporting is used to understand the interference that results from the created MU pairing. The ability to “test” the pairing of candidate co-scheduled UEs prior to creating an MU pairing may help to (1) reduce the signaling overhead from SU CSI and MU CSI reporting for evaluating each prospective MU pairing, as well as (2) decrease power consumption at the network entity and UE (s) for transmitting such CSI. Further, more efficient MU pairing may be realized and thus reduce the latency in determining a “best” MU pairing for MU-MIMO communication.

The CQI (s) reported, to the network entity from a UE, as part of MU CSI, may not only allow the network entity to determine a “best” MU pairing but may also enable the network entity to determine an MCS to use for downlink communication with each UE of the determined MU pairing. As such, additional signaling overhead generally incurred to determine the MCSs may be saved.

Introduction to Wireless Communications Networks

The techniques and methods described herein may be used for various wireless communications networks. While aspects may be described herein using terminology commonly associated with 3G, 4G, 5G, 6G, and/or other generations of wireless technologies, aspects of the present disclosure may likewise be applicable to other communications systems and standards not explicitly mentioned herein.

FIG. 1 depicts an example of a wireless communications network 100, in which aspects described herein may be implemented.

Generally, wireless communications network 100 includes various network entities (alternatively, network elements or network nodes) . A network entity is generally a communications device and/or a communications function performed by a communications device (e.g., a user equipment (UE) , a base station (BS) , a component of a BS, a server, etc. ) . As such communications devices are part of wireless communications network 100, and facilitate wireless communications, such communications devices may be referred to as wireless communications devices. For example, various functions of a network as well as various devices associated with and interacting with a network may be considered network entities. Further, wireless communications network 100 includes terrestrial aspects, such as ground-based network entities (e.g., BSs 102) , and non-terrestrial aspects (also referred to herein as non-terrestrial network entities) , such as satellite 140 and/or aerial or spaceborne platform (s) , which may include network entities on-board (e.g., one or more BSs) capable of communicating with other network elements (e.g., terrestrial BSs) and UEs.

In the depicted example, wireless communications network 100 includes BSs 102, UEs 104, and one or more core networks, such as an Evolved Packet Core (EPC) 160 and 5G Core (5GC) network 190, which interoperate to provide communications services over various communications links, including wired and wireless links.

FIG. 1 depicts various example UEs 104, which may more generally include: a cellular phone, smart phone, session initiation protocol (SIP) phone, laptop, personal digital assistant (PDA) , satellite radio, global positioning system, multimedia device, video device, digital audio player, camera, game console, tablet, smart device, wearable device, vehicle, electric meter, gas pump, large or small kitchen appliance, healthcare device, implant, sensor/actuator, display, internet of things (IoT) devices, always on (AON) devices, edge processing devices, data centers, or other similar devices. UEs 104 may also be referred to more generally as a mobile device, a wireless device, a station, a mobile station, a subscriber station, a mobile subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a remote device, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, and others.

BSs 102 wirelessly communicate with (e.g., transmit signals to or receive signals from) UEs 104 via communications links 120. The communications links 120 between BSs 102 and UEs 104 may include uplink (UL) (also referred to as reverse link) transmissions from a UE 104 to a BS 102 and/or downlink (DL) (also referred to as forward link) transmissions from a BS 102 to a UE 104. The communications links 120 may use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity in various aspects.

BSs 102 may generally include: a NodeB, enhanced NodeB (eNB) , next generation enhanced NodeB (ng-eNB) , next generation NodeB (gNB or gNodeB) , access point, base transceiver station, radio base station, radio transceiver, transceiver function, transmission reception point, and/or others. Each of BSs 102 may provide communications coverage for a respective coverage area 110, which may sometimes be referred to as a cell, and which may overlap in some cases (e.g., small cell 102’ may have a coverage area 110’ that overlaps the coverage area 110 of a macro cell) . A BS may, for example, provide communications coverage for a macro cell (covering relatively large geographic area) , a pico cell (covering relatively smaller geographic area, such as a sports stadium) , a femto cell (relatively smaller geographic area (e.g., a home) ) , and/or other types of cells.

Generally, a cell may refer to a portion, partition, or segment of wireless communication coverage served by a network entity within a wireless communication network. A cell may have geographic characteristics, such as a geographic coverage area, as well as radio frequency characteristics, such as time and/or frequency resources dedicated to the cell. For example, a specific geographic coverage area may be covered by multiple cells employing different frequency resources (e.g., bandwidth parts) and/or different time resources. As another example, a specific geographic coverage area may be covered by a single cell. In some contexts (e.g., a carrier aggregation scenario and/or multi-connectivity scenario) , the terms “cell” or “serving cell” may refer to or correspond to a specific carrier frequency (e.g., a component carrier) used for wireless communications, and a “cell group” may refer to or correspond to multiple carriers used for wireless communications. As examples, in a carrier aggregation scenario, a UE may communicate on multiple component carriers corresponding to multiple (serving) cells in the same cell group, and in a multi-connectivity (e.g., dual connectivity) scenario, a UE may communicate on multiple component carriers corresponding to multiple cell groups.

While BSs 102 are depicted in various aspects as unitary communications devices, BSs 102 may be implemented in various configurations. For example, one or more components of a base station may be disaggregated, including a central unit (CU) , one or more distributed units (DUs) , one or more radio units (RUs) , a Near-Real Time (Near-RT) RAN Intelligent Controller (RIC) , or a Non-Real Time (Non-RT) RIC, to name a few examples. In another example, various aspects of a base station may be virtualized. More generally, a base station (e.g., BS 102) may include components that are located at a single physical location or components located at various physical locations. In examples in which a base station includes components that are located at various physical locations, the various components may each perform functions such that, collectively, the various components achieve functionality that is similar to a base station that is located at a single physical location. In some aspects, a base station including components that are located at various physical locations may be referred to as a disaggregated radio access network architecture, such as an Open RAN (O-RAN) or Virtualized RAN (VRAN) architecture. FIG. 2 depicts and describes an example disaggregated base station architecture.

Different BSs 102 within wireless communications network 100 may also be configured to support different radio access technologies, such as 3G, 4G, and/or 5G. For example, BSs 102 configured for 4G LTE (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN) ) may interface with the EPC 160 through first backhaul links 132 (e.g., an S1 interface) . BSs 102 configured for 5G (e.g., 5G NR or Next Generation RAN (NG-RAN) ) may interface with 5GC 190 through second backhaul links 184. BSs 102 may communicate directly or indirectly (e.g., through the EPC 160 or 5GC 190) with each other over third backhaul links 134 (e.g., X2 interface) , which may be wired or wireless.

Wireless communications network 100 may subdivide the electromagnetic spectrum into various classes, bands, channels, or other features. In some aspects, the subdivision is provided based on wavelength and frequency, where frequency may also be referred to as a carrier, a subcarrier, a frequency channel, a tone, or a subband. For example, 3GPP currently defines Frequency Range 1 (FR1) as including 410 MHz-7125 MHz, which is often referred to (interchangeably) as “Sub-6 GHz” . Similarly, 3GPP currently defines Frequency Range 2 (FR2) as including 24,250 MHz -71,000 MHz, which is sometimes referred to (interchangeably) as a “millimeter wave” ( “mmW” or “mmWave” ) . In some cases, FR2 may be further defined in terms of sub-ranges, such as a first sub-range FR2-1 including 24,250 MHz -52,600 MHz and a second sub-range FR2-2 including 52,600 MHz -71,000 MHz. A base station configured to communicate using mmWave/near mmWave radio frequency bands (e.g., a mmWave base station such as BS 180) may utilize beamforming (e.g., 182) with a UE (e.g., 104) to improve path loss and range.

The communications links 120 between BSs 102 and, for example, UEs 104, may be through one or more carriers, which may have different bandwidths (e.g., 5, 10, 15, 20, 100, 400, and/or other MHz) , and which may be aggregated in various aspects. Carriers may or may not be adjacent to each other. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL than for UL) .

Communications using higher frequency bands may have higher path loss and a shorter range compared to lower frequency communications. Accordingly, certain base stations (e.g., 180 in FIG. 1) may utilize beamforming 182 with a UE 104 to improve path loss and range. For example, BS 180 and the UE 104 may each include a plurality of antennas, such as antenna elements, antenna panels, and/or antenna arrays to facilitate the beamforming. In some cases, BS 180 may transmit a beamformed signal to UE 104 in one or more transmit directions 182’. UE 104 may receive the beamformed signal from the BS 180 in one or more receive directions 182”. UE 104 may also transmit a beamformed signal to the BS 180 in one or more transmit directions 182”. BS 180 may also receive the beamformed signal from UE 104 in one or more receive directions 182’. BS 180 and UE 104 may then perform beam training to determine the best receive and transmit directions for each of BS 180 and UE 104. Notably, the transmit and receive directions for BS 180 may or may not be the same. Similarly, the transmit and receive directions for UE 104 may or may not be the same.

Wireless communications network 100 further includes a Wi-Fi AP 150 in communication with Wi-Fi stations (STAs) 152 via communications links 154 in, for example, a 2.4 GHz and/or 5 GHz unlicensed frequency spectrum.

Certain UEs 104 may communicate with each other using device-to-device (D2D) communications link 158. D2D communications link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH) , a physical sidelink discovery channel (PSDCH) , a physical sidelink shared channel (PSSCH) , a physical sidelink control channel (PSCCH) , and/or a physical sidelink feedback channel (PSFCH) .

EPC 160 may include various functional components, including: a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and/or a Packet Data Network (PDN) Gateway 172, such as in the depicted example. MME 162 may be in communication with a Home Subscriber Server (HSS) 174. MME 162 is the control node that processes the signaling between the UEs 104 and the EPC 160. Generally, MME 162 provides bearer and connection management.

Generally, user Internet protocol (IP) packets are transferred through Serving Gateway 166, which itself is connected to PDN Gateway 172. PDN Gateway 172 provides UE IP address allocation as well as other functions. PDN Gateway 172 and the BM-SC 170 are connected to IP Services 176, which may include, for example, the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a Packet Switched (PS) streaming service, and/or other IP services.

BM-SC 170 may provide functions for MBMS user service provisioning and delivery. BM-SC 170 may serve as an entry point for content provider MBMS transmission, may be used to authorize and initiate MBMS Bearer Services within a public land mobile network (PLMN) , and/or may be used to schedule MBMS transmissions. MBMS Gateway 168 may be used to distribute MBMS traffic to the BSs 102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area broadcasting a particular service, and/or may be responsible for session management (start/stop) and for collecting eMBMS related charging information.

5GC 190 may include various functional components, including: an Access and Mobility Management Function (AMF) 192, other AMFs 193, a Session Management Function (SMF) 194, and a User Plane Function (UPF) 195. AMF 192 may be in communication with Unified Data Management (UDM) 196.

AMF 192 is a control node that processes signaling between UEs 104 and 5GC 190. AMF 192 provides, for example, quality of service (QoS) flow and session management.

Internet protocol (IP) packets are transferred through UPF 195, which is connected to the IP Services 197, and which provides UE IP address allocation as well as other functions for 5GC 190. IP Services 197 may include, for example, the Internet, an intranet, an IMS, a PS streaming service, and/or other IP services.

In various aspects, a network entity or network node can be implemented as an aggregated base station, as a disaggregated base station, a component of a base station, an integrated access and backhaul (IAB) node, a relay node, a sidelink node, to name a few examples.

FIG. 2 depicts an example disaggregated base station 200 architecture. The disaggregated base station 200 architecture may include one or more central units (CUs) 210 that can communicate directly with a core network 220 via a backhaul link, or indirectly with the core network 220 through one or more disaggregated base station units (such as a Near-Real Time (Near-RT) RAN Intelligent Controller (RIC) 225 via an E2 link, or a Non-Real Time (Non-RT) RIC 215 associated with a Service Management and Orchestration (SMO) Framework 205, or both) . A CU 210 may communicate with one or more distributed units (DUs) 230 via respective midhaul links, such as an F1 interface. The DUs 230 may communicate with one or more radio units (RUs) 240 via respective fronthaul links. The RUs 240 may communicate with respective UEs 104 via one or more radio frequency (RF) access links. In some implementations, the UE 104 may be simultaneously served by multiple RUs 240.

Each of the units, e.g., the CUs 210, the DUs 230, the RUs 240, as well as the Near-RT RICs 225, the Non-RT RICs 215 and the SMO Framework 205, may include one or more interfaces or be coupled to one or more interfaces configured to receive or transmit signals, data, or information (collectively, signals) via a wired or wireless transmission medium. Each of the units, or an associated processor or controller providing instructions to the communications interfaces of the units, can be configured to communicate with one or more of the other units via the transmission medium. For example, the units can include a wired interface configured to receive or transmit signals over a wired transmission medium to one or more of the other units. Additionally or alternatively, the units can include a wireless interface, which may include a receiver, a transmitter or transceiver (such as a radio frequency (RF) transceiver) , configured to receive or transmit signals, or both, over a wireless transmission medium to one or more of the other units.

In some aspects, the CU 210 may host one or more higher layer control functions. Such control functions can include radio resource control (RRC) , packet data convergence protocol (PDCP) , service data adaptation protocol (SDAP) , or the like. Each control function can be implemented with an interface configured to communicate signals with other control functions hosted by the CU 210. The CU 210 may be configured to handle user plane functionality (e.g., Central Unit -User Plane (CU-UP) ) , control plane functionality (e.g., Central Unit -Control Plane (CU-CP) ) , or a combination thereof. In some implementations, the CU 210 can be logically split into one or more CU-UP units and one or more CU-CP units. The CU-UP unit can communicate bidirectionally with the CU-CP unit via an interface, such as the El interface when implemented in an O-RAN configuration. The CU 210 can be implemented to communicate with the DU 230, as necessary, for network control and signaling.

The DU 230 may correspond to a logical unit that includes one or more base station functions to control the operation of one or more RUs 240. In some aspects, the DU 230 may host one or more of a radio link control (RLC) layer, a medium access control (MAC) layer, and one or more high physical (PHY) layers (such as modules for forward error correction (FEC) encoding and decoding, scrambling, modulation and demodulation, or the like) depending, at least in part, on a functional split, such as those defined by the 3^rd Generation Partnership Project (3GPP) . In some aspects, the DU 230 may further host one or more low PHY layers. Each layer (or module) can be implemented with an interface configured to communicate signals with other layers (and modules) hosted by the DU 230, or with the control functions hosted by the CU 210.

Lower-layer functionality can be implemented by one or more RUs 240. In some deployments, an RU 240, controlled by a DU 230, may correspond to a logical node that hosts RF processing functions, or low-PHY layer functions (such as performing fast Fourier transform (FFT) , inverse FFT (iFFT) , digital beamforming, physical random access channel (PRACH) extraction and filtering, or the like) , or both, based at least in part on the functional split, such as a lower layer functional split. In such an architecture, the RU (s) 240 can be implemented to handle over the air (OTA) communications with one or more UEs 104. In some implementations, real-time and non-real-time aspects of control and user plane communications with the RU (s) 240 can be controlled by the corresponding DU 230. In some scenarios, this configuration can enable the DU (s) 230 and the CU 210 to be implemented in a cloud-based RAN architecture, such as a vRAN architecture.

The SMO Framework 205 may be configured to support RAN deployment and provisioning of non-virtualized and virtualized network elements. For non-virtualized network elements, the SMO Framework 205 may be configured to support the deployment of dedicated physical resources for RAN coverage requirements which may be managed via an operations and maintenance interface (such as an O1 interface) . For virtualized network elements, the SMO Framework 205 may be configured to interact with a cloud computing platform (such as an open cloud (O-Cloud) 290) to perform network element life cycle management (such as to instantiate virtualized network elements) via a cloud computing platform interface (such as an O2 interface) . Such virtualized network elements can include, but are not limited to, CUs 210, DUs 230, RUs 240 and Near-RT RICs 225. In some implementations, the SMO Framework 205 can communicate with a hardware aspect of a 4G RAN, such as an open eNB (O-eNB) 211, via an O1 interface. Additionally, in some implementations, the SMO Framework 205 can communicate directly with one or more DUs 230 and/or one or more RUs 240 via an O1 interface. The SMO Framework 205 also may include a Non-RT RIC 215 configured to support functionality of the SMO Framework 205.

The Non-RT RIC 215 may be configured to include a logical function that enables non-real-time control and optimization of RAN elements and resources, Artificial Intelligence/Machine Learning (AI/ML) workflows including model training and updates, or policy-based guidance of applications/features in the Near-RT RIC 225. The Non-RT RIC 215 may be coupled to or communicate with (such as via an A1 interface) the Near-RT RIC 225. The Near-RT RIC 225 may be configured to include a logical function that enables near-real-time control and optimization of RAN elements and resources via data collection and actions over an interface (such as via an E2 interface) connecting one or more CUs 210, one or more DUs 230, or both, as well as an O-eNB, with the Near-RT RIC 225.

In some implementations, to generate AI/ML models to be deployed in the Near-RT RIC 225, the Non-RT RIC 215 may receive parameters or external enrichment information from external servers. Such information may be utilized by the Near-RT RIC 225 and may be received at the SMO Framework 205 or the Non-RT RIC 215 from non-network data sources or from network functions. In some examples, the Non-RT RIC 215 or the Near-RT RIC 225 may be configured to tune RAN behavior or performance. For example, the Non-RT RIC 215 may monitor long-term trends and patterns for performance and employ AI/ML models to perform corrective actions through the SMO Framework 205 (such as reconfiguration via O1) or via creation of RAN management policies (such as A1 policies) .

FIG. 3 depicts aspects of an example BS 102 and a UE 104.

Generally, BS 102 includes various processors (e.g., 318, 320, 330, 338, and 340) , antennas 334a-t (collectively 334) , transceivers 332a-t (collectively 332) , which include modulators and demodulators, and other aspects, which enable wireless transmission of data (e.g., data source 312) and wireless reception of data (e.g., data sink 314) . For example, BS 102 may send and receive data between BS 102 and UE 104. BS 102 includes controller/processor 340, which may be configured to implement various functions described herein related to wireless communications. Note that the BS 102 may have a disaggregated architecture as described herein with respect to FIG. 2.

Generally, UE 104 includes various processors (e.g., 358, 364, 366, 370, and 380) , antennas 352a-r (collectively 352) , transceivers 354a-r (collectively 354) , which include modulators and demodulators, and other aspects, which enable wireless transmission of data (e.g., retrieved from data source 362) and wireless reception of data (e.g., provided to data sink 360) . UE 104 includes controller/processor 380, which may be configured to implement various functions described herein related to wireless communications.

In regards to an example downlink transmission, BS 102 includes a transmit processor 320 that may receive data from a data source 312 and control information from a controller/processor 340. The control information may be for the physical broadcast channel (PBCH) , physical control format indicator channel (PCFICH) , physical hybrid automatic repeat request (HARQ) indicator channel (PHICH) , physical downlink control channel (PDCCH) , group common PDCCH (GC PDCCH) , and/or others. The data may be for the physical downlink shared channel (PDSCH) , in some examples.

Transmit processor 320 may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. Transmit processor 320 may also generate reference symbols, such as for the primary synchronization signal (PSS) , secondary synchronization signal (SSS) , PBCH demodulation reference signal (DMRS) , and channel state information reference signal (CSI-RS) .

Transmit (TX) multiple-input multiple-output (MIMO) processor 330 may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and/or the reference symbols, if applicable, and may provide output symbol streams to the modulators (MODs) in transceivers 332a-332t. Each modulator in transceivers 332a- 332t may process a respective output symbol stream to obtain an output sample stream. Each modulator may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. Downlink signals from the modulators in transceivers 332a-332t may be transmitted via the antennas 334a-334t, respectively.

In order to receive the downlink transmission, UE 104 includes antennas 352a-352r that may receive the downlink signals from the BS 102 and may provide received signals to the demodulators (DEMODs) in transceivers 354a-354r, respectively. Each demodulator in transceivers 354a-354r may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulator may further process the input samples to obtain received symbols.

RX MIMO detector 356 may obtain received symbols from all the demodulators in transceivers 354a-354r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. Receive processor 358 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for the UE 104 to a data sink 360, and provide decoded control information to a controller/processor 380.

In regards to an example uplink transmission, UE 104 further includes a transmit processor 364 that may receive and process data (e.g., for the PUSCH) from a data source 362 and control information (e.g., for the physical uplink control channel (PUCCH) ) from the controller/processor 380. Transmit processor 364 may also generate reference symbols for a reference signal (e.g., for the sounding reference signal (SRS) ) . The symbols from the transmit processor 364 may be precoded by a TX MIMO processor 366 if applicable, further processed by the modulators in transceivers 354a-354r (e.g., for SC-FDM) , and transmitted to BS 102.

At BS 102, the uplink signals from UE 104 may be received by antennas 334a-t, processed by the demodulators in transceivers 332a-332t, detected by a RX MIMO detector 336 if applicable, and further processed by a receive processor 338 to obtain decoded data and control information sent by UE 104. Receive processor 338 may provide the decoded data to a data sink 314 and the decoded control information to the controller/processor 340.

Memories 342 and 382 may store data and program codes for BS 102 and UE 104, respectively.

Scheduler 344 may schedule UEs for data transmission on the downlink and/or uplink.

In various aspects, BS 102 may be described as transmitting and receiving various types of data associated with the methods described herein. In these contexts, “transmitting” may refer to various mechanisms of outputting data, such as outputting data from data source 312, scheduler 344, memory 342, transmit processor 320, controller/processor 340, TX MIMO processor 330, transceivers 332a-t, antenna 334a-t, and/or other aspects described herein. Similarly, “receiving” may refer to various mechanisms of obtaining data, such as obtaining data from antennas 334a-t, transceivers 332a-t, RX MIMO detector 336, controller/processor 340, receive processor 338, scheduler 344, memory 342, and/or other aspects described herein.

In various aspects, UE 104 may likewise be described as transmitting and receiving various types of data associated with the methods described herein. In these contexts, “transmitting” may refer to various mechanisms of outputting data, such as outputting data from data source 362, memory 382, transmit processor 364, controller/processor 380, TX MIMO processor 366, transceivers 354a-t, antenna 352a-t, and/or other aspects described herein. Similarly, “receiving” may refer to various mechanisms of obtaining data, such as obtaining data from antennas 352a-t, transceivers 354a-t, RX MIMO detector 356, controller/processor 380, receive processor 358, memory 382, and/or other aspects described herein.

In some aspects, a processor may be configured to perform various operations, such as those associated with the methods described herein, and transmit (output) to or receive (obtain) data from another interface that is configured to transmit or receive, respectively, the data.

In various aspects, artificial intelligence (AI) processors 318 and 370 may perform AI processing for BS 102 and/or UE 104, respectively. The AI processor 318 may include AI accelerator hardware or circuitry such as one or more neural processing units (NPUs) , one or more neural network processors, one or more tensor processors, one or more deep learning processors, etc. The AI processor 370 may likewise include AI accelerator hardware or circuitry. As an example, the AI processor 370 may perform AI- based beam management, AI-based channel state feedback (CSF) , AI-based antenna tuning, and/or AI-based positioning (e.g., non-line of sight positioning prediction) . In some cases, the AI processor 318 may process feedback from the UE 104 (e.g., CSF) using hardware accelerated AI inferences and/or AI training. The AI processor 318 may decode compressed CSF from the UE 104, for example, using a hardware accelerated AI inference associated with the CSF. In certain cases, the AI processor 318 may perform certain RAN-based functions including, for example, network planning, network performance management, energy-efficient network operations, etc.

FIGS. 4A, 4B, 4C, and 4D depict aspects of data structures for a wireless communications network, such as wireless communications network 100 of FIG. 1.

In particular, FIG. 4A is a diagram 400 illustrating an example of a first subframe within a 5G (e.g., 5G NR) frame structure, FIG. 4B is a diagram 430 illustrating an example of DL channels within a 5G subframe, FIG. 4C is a diagram 450 illustrating an example of a second subframe within a 5G frame structure, and FIG. 4D is a diagram 480 illustrating an example of UL channels within a 5G subframe.

Wireless communications systems may utilize orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) on the uplink and downlink. Such systems may also support half-duplex operation using time division duplexing (TDD) . OFDM and single-carrier frequency division multiplexing (SC-FDM) partition the system bandwidth (e.g., as depicted in FIGS. 4B and 4D) into multiple orthogonal subcarriers. Each subcarrier may be modulated with data. Modulation symbols may be sent in the frequency domain with OFDM and/or in the time domain with SC-FDM.

A wireless communications frame structure may be frequency division duplex (FDD) , in which, for a particular set of subcarriers, subframes within the set of subcarriers are dedicated for either DL or UL. Wireless communications frame structures may also be time division duplex (TDD) , in which, for a particular set of subcarriers, subframes within the set of subcarriers are dedicated for both DL and UL.

In FIG. 4A and 4C, the wireless communications frame structure is TDD where D is DL, U is UL, and X is flexible for use between DL/UL. UEs may be configured with a slot format through a received slot format indicator (SFI) (dynamically through DL control information (DCI) , or semi-statically/statically through radio resource control (RRC) signaling) . In the depicted examples, a 10 ms frame is divided into 10 equally sized 1 ms subframes. Each subframe may include one or more time slots. In some examples, each slot may include 12 or 14 symbols, depending on the cyclic prefix (CP) type (e.g., 12 symbols per slot for an extended CP or 14 symbols per slot for a normal CP) . Subframes may also include mini-slots, which generally have fewer symbols than an entire slot. Other wireless communications technologies may have a different frame structure and/or different channels.

In certain aspects, the number of slots within a subframe (e.g., a slot duration in a subframe) is based on a numerology, which may define a frequency domain subcarrier spacing and symbol duration as further described herein. In certain aspects, given a numerology μ, there are 2^μ slots per subfrarne. Thus, numerologies (μ) 0 to 6 may allow for 1, 2, 4, 8, 16, 32, and 64 slots, respectively, per subframe. In some cases, the extended CP (e.g., 12 symbols per slot) may be used with a specific numerology, e.g., numerology 2 allowing for 4 slots per subframe. The subcarrier spacing and symbol length/duration are a function of the numerology. The subcarrier spacing may be equal to 2^μ × 15 kHz, where μ is the numerology 0 to 6. As an example, the numerology μ ＝ 0 corresponds to a subcarrier spacing of 15 kHz, and the numerology μ ＝ 6 corresponds to a subcarrier spacing of 960 kHz. The symbol length/duration is inversely related to the subcarrier spacing. FIGS. 4A, 4B, 4C, and 4D provide an example of a slot format having 14 symbols per slot (e.g., a normal CP) and a numerology μ ＝ 2 with 4 slots per subframe. In such a case, the slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 μs.

As depicted in FIGS. 4A, 4B, 4C, and 4D, a resource grid may be used to represent the frame structure. Each time slot includes a resource block (RB) (also referred to as physical RBs (PRBs) ) that extends, for example, 12 consecutive subcarriers. The resource grid is divided into multiple resource elements (REs) . The number of bits carried by each RE depends on the modulation scheme including, for example, quadrature phase shift keying (QPSK) or quadrature amplitude modulation (QAM) .

As illustrated in FIG. 4A, some of the REs carry reference (pilot) signals (RS) for a UE (e.g., UE 104 of FIGS. 1 and 3) . The RS may include demodulation RS (DMRS) and/or channel state information reference signals (CSI-RS) for channel estimation at the UE.The RS may also include beam measurement RS (BRS) , beam refinement RS (BRRS) , and/or phase tracking RS (PT-RS) .

FIG. 4B illustrates an example of various DL channels within a subframe of a frame. The physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs) , each CCE including, for example, nine RE groups (REGs) , each REG including, for example, four consecutive REs in an OFDM symbol.

A primary synchronization signal (PSS) may be within symbol 2 of particular subframes of a frame. The PSS is used by a UE (e.g., 104 of FIGS. 1 and 3) to determine subframe/symbol timing and a physical layer identity.

A secondary synchronization signal (SSS) may be within symbol 4 of particular subframes of a frame. The SSS is used by a UE to determine a physical layer cell identity group number and radio frame timing.

Based on the physical layer identity and the physical layer cell identity group number, the UE can determine a physical cell identifier (PCI) . Based on the PCI, the UE can determine the locations of the aforementioned DMRS. The physical broadcast channel (PBCH) , which carries a master information block (MIB) , may be logically grouped with the PSS and SSS to form a synchronization signal (SS) /PBCH block (SSB) , and in some cases, referred to as a synchronization signal block (SSB) . The MIB provides a number of RBs in the system bandwidth and a system frame number (SFN) . The physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted through the PBCH such as system information blocks (SIBs) , and/or paging messages.

As illustrated in FIG. 4C, some of the REs carry DMRS (indicated as R for one particular configuration, but other DMRS configurations are possible) for channel estimation at the base station. The UE may transmit DMRS for the PUCCH and DMRS for the PUSCH. The PUSCH DMRS may be transmitted, for example, in the first one or two symbols of the PUSCH. The PUCCH DMRS may be transmitted in different configurations depending on whether short or long PUCCHs are transmitted and depending on the particular PUCCH format used. UE 104 may transmit sounding reference signals (SRS) . The SRS may be transmitted, for example, in the last symbol of a subframe. The SRS may have a comb structure, and a UE may transmit SRS on one of the combs. The SRS may be used by a base station for channel quality estimation to enable frequency-dependent scheduling on the UL.

FIG. 4D illustrates an example of various UL channels within a subframe of a frame. The PUCCH may be located as indicated in one configuration. The PUCCH carries uplink control information (UCI) , such as scheduling requests, a channel quality indicator (CQI) , a precoding matrix indicator (PMI) , a rank indicator (RI) , and HARQ ACK/NACK feedback. The PUSCH carries data, and may additionally be used to carry a buffer status report (BSR) , a power headroom report (PHR) , and/or UCI.

Aspects Related to MIMO

In multi-antenna wireless communication systems, spatial multiplexing may be used to increase the spectral efficiency (e.g., a measure of a bit rate that is transmitted in a given communication channel) . Spatial multiplexing refers to transmitting multiple streams (e.g., independently encoded data) along different beams. A beam is defined by a scaling of an amplitude and a phase corresponding to each antenna. Antenna-specific weighting of an amplitude and a phase are applied to different data streams and the data streams are mapped to different antennas. A signal is said to be transmitted along a beam ifthe signal is transmitted on all antennas using the scaling corresponding to each antenna. A spatial multiplexing scheme is referred to as a SU-MIMO scheme when all streams transmitted are for a single user (e.g., such as UE 104 depicted and described with respect to FIG. 1 and 3) and is referred to as a MU-MIMO scheme when two or more streams are transmitted of which at least two streams are meant for two different users.

FIG. 5A depicts an example SU-MIMO scheme 500a. As shown in FIG. 5A, a network entity 502 (e.g., such as BS 102 depicted and described with respect to FIG. 1 and 3 or a disaggregated base station depicted and described with respect to FIG. 2) may utilize SU-MIMO to simultaneously transmit data stream 506 and data stream 508 to a UE 504 (1) (e.g., such as UE 104 depicted and described with respect to FIG. 1 and 3) . Different beams may be used to transmit data stream 506 and data stream 508 to UE 504 (1) .

The beams, number of data streams (also referred to as “layers” ) , and/or precoding (e.g., a signal processing technique used to manipulate transmitted signals before transmission to optimize received signals at a receiver) used for downlink communication with UE 504 (1) , to achieve reliable and efficient communication, may depend on a channel realization of UE 504 (1) . However, this channel knowledge may not be available at network entity 502. When the channel knowledge is not available at network entity 502, the network entity 502 may rely on some form of feedback from the UE 504 (1) . Accordingly, as shown in FIG. 5A, UE 504 (1) may send CSI feedback 510 to the network entity 502.

For example, for SU-MIMO, UE 504 (1) may send, to network entity 502, a CSI report including one or more CSI parameters, such as a rank index (RI) , a precoding matrix indicator (PMI) , and/or a channel quality indicator (CQI) . RI may represent a rank, or a number of data streams requested for downlink transmissions. The maximum rank indicated (and supported) may be equal to the minimum of the number of transmit antennas N_t at network entity 502 and the number of receive antennas N_r at UE 504 (1) . For example, in FIG. 5A, the max rank may be equal to two. In certain embodiments, the PMI may indicate the UE’s preferred precoding for downlink transmissions. CQI may be an indicator of channel quality at UE 504 (1) , and more specifically, average channel conditions and/or interference levels at UE 504 (1) .

A set of codebooks may be defined that contain several different precoding matrices corresponding to each rank. A precoding matrix for rank r is generally an N_t × r matrix, where each column of the precoding matrix corresponds to a beam. In one example, UE 504 (1) measures the channel on the downlink using reference signals (e.g., CSI-RSs) transmitted by network entity 502. UE 504 (1) then searches over all rank and precoding matrix combinations to find the rank and precoding matrix that is predicted to have the best performance. The best rank and precoding matrix combination may be a rank and precoding matrix that provides the best data rate over all streams and over the configured reporting bandwidth. This rank and precoding matrix may be reported to network entity 502 in a CSI report as RI and PMI, respectively. Network entity 502 may transmit downlink data transmissions to UE 504 (1) based on this information.

FIG. 5B depicts an example MU-MIMO scheme 500b. As shown in FIG. 5B, network entity 502 may simultaneously transmit a data stream 536 to UE 504 (1) and a data stream 538 to another UE, e.g., UE 504 (2) , using the same antenna elements. For example, network entity may transmit data stream 536 to UE 504 (1) and data stream 538 to UE 504 (2) on the same time-frequency resources using different spatial precoders. UE 504 (1) and UE 504 (2) (e.g., the co-scheduled UEs) may use different orthogonal DMRS ports in a same or different code division multiplexing (CDM) group.

Similar to SU-MIMO, channel state feedback may be provided by the scheduled UEs 504 to network entity 502. For example, UE 504 (1) may send CSI feedback 546 to network entity 502, where CSI feedback 546 includes one or more CSI parameters, such as RI, PMI, and/or CQI. Similarly, UE 504 (2) may send CSI feedback 548 to network entity 502, where CSI feedback 548 includes one or more CSI parameters, such as RI, PMI, and/or CQI. Network entity 502 may simultaneously transmit downlink data transmissions to UE 504 (1) and UE 504 (2) based on the reported CSI parameter (s) .

Example Interference Measurement Methods for CSI Feedback

As described herein, CSI feedback, provided by a UE, may include CQI, which is a metric representing a measure of quality for a given channel. An accurate interference measurement and channel measurement may be used to calculate the CQI.

Interference occurs when wireless communication signals in a wireless communication network are disrupted or weakened, which may lead to reduced quality of service and decreased capacity in the network. Interference may include, for example, (1) inter-cell interference and (2) intra-cell interference. Inter-cell interference generally refers to the signal from one cell interfering with the signal from another cell. Intra-cell interference, on the other hand, generally refers to interference caused by wireless signals within a same cell and associated with different entities within the cell, e.g., UEs and/or network entities. Multiple methods may be used to obtain interference measurements.

For example, a first method of interference measurement may rely on NZP CSI-RSs, which is one type of RS used to obtain channel measurements, to obtain a residual interference measurement based on the channel measurements. The term “non-zero-power” in NZP-CSI-RS signifies that the RS is transmitted with a power level greater than zero. A second method of interference measurement may be based on zero-power CSI interference measurement (ZP CSI-IM) (also simply referred to as “CSI-IM” ) resource elements, which may allow for direct interference measurement. The first method of interference measurement, using NZP CSI-RSs, may generally be used to measure intra-cell interference, while the second method of interference measurement, using CSI-IM resource elements, may generally be used to measure inter-cell interference.

FIGS. 6A-6B depict example use of NZP CSI-RSs for interference measurement. As shown in FIG. 6A, two NZP CSI-RSs are allocated on a fourth OFDM symbol in a scheduled subframe 602 of a serving network entity (e.g., serving BS) for a UE. These two NZP CSI-RSs may collide with NZP CSI-RS resource elements of subframes 604, 606 associated with a first interfering network entity and a second interfering network entity (e.g., network entities scheduling interfering signals) , respectively (e.g., where the NZP CSI-RSs are also allocated on a fourth OFDM symbol in each subframe 604, 606) . Interference may be measured, by a UE, based on these interfering signals from the interfering network entities. In this case, the interference measured may correspond to non-precoded interference.

Alternatively, as shown in FIG. 6B, NZP CSI-RSs allocated on a fourth OFDM symbol in a scheduled subframe 608 ora serving network entity may overlap with user data from a first interfering network entity (e.g., shown at 611 in the fourth OFDM symbol in subframe 610) and user data from a second interfering network entity (e.g., shown at 613 in the fourth OFDM symbol in subframe 612) . Interference may be measured, by a UE, based on these interfering signals from the interfering network entities. In this case, the estimated interference may depend on the user-specific precoding used in cells corresponding to the first interfering network entity and the second interfering network entity.

Though the examples illustrated in FIGS. 6A and 6B depict example interference based on signals from two network entities, in some other examples, the estimated interference may be based on signals from only a single network entity or from more than two network entities.

In the second method of interference measurement, which uses CSI-IM resources, a set of resource elements in one subframe may be configured on which the interference may be measured directly by the UE. CSI-IM resources may contain zero power resource elements. However, it is noted that CSI-IM and ZP CSI-RS may have different functions. For example, CSI-IM may define the set of resource elements from which interference may be measured while ZP CSI-RS may define a set of resource elements where a downlink data channel (e.g., PDSCH) is not mapped and a UE cannot make any assumptions of the content of such resources. FIG. 6C depicts example use of CSI-IM resources for interference measurement.

As shown in FIG. 6C, a network entity serving a UE (e.g., a serving BS) may reserve (e.g., schedule) two resource elements in a subframe 620 for NZP CSI-RS for channel estimation at a UE, as well as four resource elements in the subframe 620 for CSI-IM for interference measurement by the UE. The serving network entity may not transmit any data on the resource elements communicating CSI-IM. The first interfering network entity and the second interfering network entity may transmit data on the same resource elements that are scheduled for the CSI-IM, in their respective subframes 622, 624. Thus, the UE may measure interference from the other interfering network entities (e.g., associated with neighboring cells of the serving cell of the UE) .

CSI-IM may be configured for periodic, semi-persistent, or aperiodic transmission. In the case of periodic CSI-IM transmission, a UE may assume that a configured CSI-IM transmission occurs every Nth slot. In the case of aperiodic CSI-IM transmission, no periodicity may be configured. Rather, a UE may be explicitly informed ( “triggered” ) about each CSI-IM resource scheduled by means of signaling in a DCI.

For example, multiple aperiodic CSI-IM resource sets may be configured at a UE in one CSI reporting setting. Each CSI-IM resource set may include K ≥ 1 CSI-IM resource (s) . Each of the CSI-IM resource sets may be associated with a “trigger state, ” and a network entity may use a CSI request field in an uplink grant DCI to select (e.g., activate) one aperiodic CSI-IM resource set for CSI reporting.

FIG. 7 depicts example use of CSI-IM resources for CSI reporting, including CQI. As shown in FIG. 7, different time and frequency patterns for CSI-IM resources may be configured at a UE. For example, CSI-IM resources may be configured via radio resource control (RRC) signaling. The CSI-IM resources may have a first time-frequency pattern shown at 722 or a second time-frequency pattern shown at 724. The RRC signaling used to configure the CSI-IM resources may include (1) a subcarrierLocation-p0 or subcarrierLocation-pl parameter defining a subcarrier occupancy (or location) of a CSI-IM resource within a slot for a csi-IM-ResourceElementPattern set to “pattern0” or “pattern1” , respectively, and (2) a symbolLocation-p0 or symbolLocation-p1 defining an OFDM symbol location of the CSI-IM resource within a slot for csi-IM-ResourceElementPattern set to “pattern0′ or ′patternl” , respectively. Additionally, the RRC signaling used to configure the CSI-IM resources may include afreqBand parameter including parameters to enable configuration of a frequency-occupancy of the CSI-IM resources. A UE may assume that CSI-IM is present in each of the PRBs configured by freqBand.

Further, as shown in FIG. 7, a network entity 702 may schedule and transmit, at 712, CSI-RS (s) and CSI-IM resources for channel measurement and interference measurement, respectively, at a UE 704. UE 704 may use the CSI-RS (s) to measure the quality of the downlink channel, as well as use the CSI-IM resource (s) to measure interference, and report, at 714, this information to the network entity 702 via a CSI report. For example, as described herein, a CSI report may include one or more CSI parameters, such as RI, PMI, and/or CQI. The CQI may be a metric representing a measure of the channel quality for the downlink channel and may be based on both the channel measurement and the interference measurement obtained by UE 704. Network entity 702 may use the information included in the CSI report for downlink transmission (e.g., via a PDSCH) at 716. For example, network entity 702 may determine, at least, a best MCS to use for transmitting downlink data to UE 704. The MCS may determine how data is modulated and encoded for transmission over the air interface between network entity 702 and UE 704.

Aspects Related to MU Pairing for MU-MIMO

In certain aspects, CSI reporting (e.g., including channel state feedback based on channel and interference measurements at a UE) may be used to assist a network entity with MU pairing in MU-MIMO scenarios (e.g., such as MU-MIMO scheme 500b depicted and described with respect to FIG. 5B) .

For example, MU pairing may attempt to increase the system capacity by allocating the channel to different subgroups of UEs, while also increasing reliability of communications and minimizing potential interference for the channel. A network entity may be responsible for determining a best MU pairing for MU-MIMO communications. For example, a best MU pairing for MU-MIMO communications may be an MU pairing that achieves the greatest system capacity and communication reliability, with the least amount of channel interference. In addition to determining which UEs may be paired for MIMO communication, the network entity may also determine MCSs to use for downlink communication with each UE of the UE pairing.

Conventional methods for MU pairing and MCS determination may include multiple iterative steps. For example, to determine an initial pairing for MU-MIMO communications, multiple UEs may report, to a network entity, SU CSI to the network entity. SU CSI reported by each UE may assume that there is no intra-cell interference and that full power is allocated for transmissions with each respective UE.

Based on the SU CSI reported by each UE, the network entity may determine an MU pairing. For example, the network entity may choose a subset of UEs for MU-MIMO communications (e.g., UEs that may be co-scheduled) based on the CQI reported by each UE (e.g., included in a CSI report from each UE) . The network entity may choose a subset of UEs that achieves the greatest network capacity and communication reliability.

The network entity may also use the SU CSI reported by each of the selected UEs to compute a precoder that may be used for downlink commtmications with each UE. For example, for an MU pairing including a first UE and a second UE, the network entity may compute a first precoder to use for downlink communication with the first UE and a second precoder to use for downlink communication with the second UE.

The network entity may then use the computed precoder (s) to determine MCSs to use for communication with the co-scheduled UEs. In particular, for the example MU pairing, the network entity may transmit NZP CSI-RS (s) precoded using the precoder determined for the second UE. The first UE may measure interference from the second UE on the precoded NZP CSI-RS (s) . The first UE may determine an MU CQI based on the measured interference and report this MU CQI to the network entity (e.g., which may be reported for MU CSI) . The network entity may update the MCS for downlink communication with the first UE based on the reported MU CQI. Similar same steps may be used to also update the MCS for downlink communication with the second UE (e.g., based on reported MU CQI from the second UE) .

MU pairing, decided by the network entity alone based on SU CSI reports from multiple UEs, may not always result in the “best” MU pairing decision. As such, maximum network capacity and communication reliability, in addition to minimum interference may not be realized even with MU-CSI reporting from co-scheduled UEs to update MCS (s) used for downlink communications. Specifically, a UE determined to be MU paired (e.g., co-scheduled) with other UEs in an MU pairing determined by the network entity may only report MU CSI for the pre-determined MU pairing. For example, a UE may only report interference from other UEs for which the network entity has determined to be included in the MU pairing. In some cases, however, interference experienced by a UE from other UEs, not included in the MU pairing, may be less than the interference experienced by the UE based on the UEs included in the MU pairing. The UE and the network entity may not be aware of this reduced interference, however, given the UE may be unable to report MU CSI for other UEs not co-scheduled with the UE. As such, maximum network capacity, maximum communication reliability, and/or minimum interference may not be realized, in some cases.

In certain aspects, the MU CQI information reported by the MU paired UEs (e.g., included in MU CSI reports transmitted to the network entity) may be used by the network entity to verify whether the MU pairing is a “best” (or “good” ) MU pairing for MIMO communication that achieves maximum (or sufficient) system network capacity and communication reliability, as well as minimum co-channel interference (or co-channel interference below a maximum tolerated co-channel interference. ) In certain aspects where the MU CQI information indicates that the MU pairing is not a “best” MU pairing and/or is not a “good” MU pairing, the network entity may change the MU pairing. For example, another UE may be added to a current MU pairing (e.g., increasing the number of UEs) and/or a current co-scheduled UE may be removed from the current determined MU pairing (e.g., decreasing the number of UEs) . Any change to the UE pairing may cause or require repetition of the aforementioned steps to receive updated CSI for MU-MIMO communications, incurring an additional amount of network overhead, latency, and/or power use (e.g., for transmitting and receiving MU CSI information) .

For example, an initial MU pairing may include a first UE and a second UE. The network entity may subsequently change the MU pairing to include a third UE, such that three UEs are co-scheduled for MU-MIMO operations (e.g., three MU paired UEs) . The network entity may make this change based on updated SU CSI reported by at least the three UEs.

Updated CSI reports from the UEs may be used to determine MCSs to use for downlink communication with each of the three UEs. For example, as described above, in a first iteration, the network entity may transmit NZP CSI-RS (s) precoded using the precoder determined for the first UE. The second UE and the third UE may measure interference from the first UE on the precoded NZP CSI-RS (s) . The second UE and the third UE may each determine an MU CQI based on the measured interference and report these MU CQIs to the network entity.

In a second iteration, the network entity may transmit NZP CSI-RS (s) precoded using the precoder determined for the second UE. The first UE and the third UE may measure interference from the second UE on the precoded NZP CSI-RS (s) . The first UE and the third UE may each determine an MU CQI based on the measured interference and report these MU CQIs to the network entity.

In a third iteration, the network entity may transmit NZP CSI-RS (s) precoded using the precoder determined for the third UE. The first UE and the second UE may measure interference from the third UE on the precoded NZP CSI-RS (s) . The first UE and the second UE may each determine an MU CQI based on the measured interference and report these MU CQIs to the network entity.

The network entity may update the MCS for the first network entity, the MCS for the second network entity, and the MCS for the third network entity based on the reported MU CQIs. Thus, for an MU pairing including N UEs, a minimum of N-1 iterations may be used to determine MCSs to use for MU-MIMO transmissions.

Again, however, in this scenario because the updated MU pairing is based on SU CSI alone, the updated MU pairing may not be a “best” MU pairing that achieves maximum network capacity and communication reliability, in addition to minimum interference (and/or may not be a “good” MU pairing that achieves at least sufficient network capacity and communication reliability, in addition to interference below a tolerated interference level) .

Accordingly, improved techniques for MU pairing and MCS determination are thus described herein to provide technical solutions to the aforementioned technical problems associated with conventional MU pairing techniques.

Aspects Related to Intra-PDSCH Interference Measurement Resources for MU-MIMO Pairing and MCS Determination

In order to overcome technical problems associated with conventional methods for MU pairing and MCS determination for MU-MIMO communications, aspects described herein provide techniques utilizing ZP CSI-IM resources in downlink data transmissions. For example, resources allocated for transmitting downlink data to a UE may include one or more ZP CSI-IM resources (e.g., self-contained CSI-IM resources) . The ZP CSI-IM resource (s) may be associated with one or more UEs that may be potentially paired with the UE (e.g., the UE receiving the downlink data with the self- contained CSI-IM resources) for MU-MIMO communications (e.g., “candidate co-scheduled UEs” ) . Including ZP CSI-IM resource (s) in the downlink data transmission, from a network entity, may trigger the UE receiving the transmission to perform one or more interference measurements to estimate interference from candidate co-scheduled UE (s) that may be potentially co-scheduled with the UE during MU-MIMO communications. The UE may report MU CQI (s) , to the network entity, based on the interference measurement (s) , and the network entity may use the reported MU CQI (s) for MU pairing, MU pairing switching, and/or MCS determination.

For example, based on the reported MU CQI (s) , the network entity may determine to create an MU pairing for MU-MIMO communications (e.g., assuming the network entity is currently using SU-MIMO to communicate with the UE that reported the CQI (s) ) . The MU pairing may include the UE that reported the MU CQI (s) and one or more of the candidate co-scheduled UEs. For example, the network entity may select candidate co-scheduled UE (s) for MU pairing, for which the reported MU CQI (s) indicate low interference.

As another example, based on the reported MU CQI (s) , the network entity may determine to update a current MU pairing including the UE that reported the MU CQI (s) (e.g., assuming the network entity is currently using MU-MIMO to communicate with the UE that reported the MU CQI (s) and one or more other UEs) . Updating the MU pairing may include adding one or more candidate co-scheduled UEs to the current MU pairing, removing one or more UEs in the current MU pairing, and/or switching one or more UEs in the current MU pairing for one or more of the candidate co-scheduled UEs.

As another example, based on the reported MU CQI (s) , the network entity may determine MCS (s) to use for a candidate MU pairing involving at least one of the candidate co-scheduled UEs and the UE that reported the MU CQI (s) . As used herein, a candidate MU pairing may be a pairing of at least two UEs that are not currently paired together for MU-MIMO communications.

Example Operations of Entities in a Communications Network

FIG. 8 depicts a process flow 800 for communications in a network between a network entity 802 and a UE 804. In some aspects, the network entity 802 may be an example of the BS 102 depicted and described with respect to FIG. 1 and 3 or a disaggregated base station depicted and described with respect to FIG. 2. Similarly, the UE 804 may be an example of UE 104 depicted and described with respect to FIG. 1 and 3. However, in other aspects, UE 804 may be another type of wireless communications device and network entity 802 may be another type of network entity or network node, such as those described herein.

Process flow 800 may be used to communicate a downlink data transmission (e.g., a PDSCH) , with self-contained ZP CSI-IM resources, for the evaluation of candidate MU pairing (s) for MU-MIMO communication. For example, the self-contained ZP CSI-IM resources may be associated with candidate co-scheduled UEs, not currently paired with UE 804 for MU-MIMO communication but that may be paired with UE 804 for MU-MIMO communication.

For example, process flow 800 begins, at 812, with UE 804 receiving a configuration of one or more ZP CSI-IM resources for interference measurement. Specifically, the configuration may indicate time-frequency resources where UE 804 may measure interference (e.g., due to transmissions between the network entity one or more other UEs) . The one or more ZP CSI-IM resources may be configured for aperiodic transmission. Aperiodic transmission implies that UE 804 may not measure and report interference periodically, but may do so irregularly on demand only (e.g., such as via a DCI triggering the interference measurement) .

The ZP CSI-IM resources configured, at 812, are resources that may be injected within resources allocated for downlink data transmissions to UE 804 (e.g., self-contained ZP CSI-IM resources) . For example, the ZP CSI-IM resources may be resources confined within a scheduled PDSCH (e.g., ZP CSI-IM resources piggybacked in a PDSCH) .

In certain aspects, the configuration, received by UE 804 at 812, indicates similar configuration parameters as those in legacy ZP CSI-IM resource configurations (e.g., as described above) . For example, the configuration may include (1) a subcarrierLocation-p0 or subcarrierLocation-p1 parameter defining a subcarrier occupancy (or location) of a CSI-IM resource within a slot for a csi-IM-ResourceElementPattern set to ′pattern0′ or ′pattern1′ , respectively, and/or (2) a symbolLocation-p0 or symbolLocation-p1 defining an OFDM symbol location of the CSI-IM resource within a slot for csi-IM-ResourceElementPattern set to “pattern0” or “pattern1” , respectively. In other words, the ZP CSI-IM resource elements patterns (e.g., “pattern0” (2, 2) illustrated at 722 in FIG. 7 and “patternl” (1, 4) illustrated at 724 in FIG. 7) may be reused for the self-contained ZP CSI-IM resource configuration. However, the OFDM symbol location for each self-contained ZP CSI-IM resource configured may be different than the OFDM symbol location indicated by parameters symbolLocation-p0 or symbolLocation-p1 in the configuration. In particular, the symbol location parameter for a self-contained ZP CSI-IM resource may be re-interpreted as the location of a first OFDM symbol relative to a scheduled downlink data transmission, e.g., PDSCH, including the self-contained ZP CSI-IM resource. This is because a PDSCH may have flexible time-domain resource allocation (TDRA) . Thus, if an absolute OFDM symbol location, indicated by the configuration is used, then the ZP CSI-IM resources may not be confined within the time-frequency resources allocated for the PDSCH.

Additionally, in certain aspects, the configuration may indicate a freqBand parameter (also referred to herein as a “frequency domain occupation parameter” ) configuring a frequency occupancy of the ZP CSI-IM resources. Although this parameter may be included in the configuration received by UE 804 at 812, UE 804 may not be required to measure interference for this ZP CSI-IM resource outside of a scheduled downlink data transmission (e.g., a PDSCH containing ZP CSI-IM resource (s) ) . For example, if part of the frequency occupied by a ZP-CSI-IM resource contained within a PDSCH falls outside of the frequency occupied by the PDSCH, a UE receiving the PDSCH may not be required to measure interference for the frequency occupied by the ZP CSI-IM resource outside of the frequency occupied by the PDSCH.

Alternatively, in certain other aspects, the configuration may not indicate the freqBand parameter (e.g., the “frequency domain occupation parameter” ) configuring a frequency occupancy for the ZP CSI-IM resources. Instead, the frequency for interference measurement may be determined based on the frequency of a downlink data transmission containing ZP CSI-IM resource (s) for interference measurement.

Process flow 800 proceeds, at 814, with UE 804 receiving from network entity 802, a DCI scheduling a downlink data transmission (e.g., a PDSCH) and triggering the activation of one or more ZP CSI-IM resources configured at UE 804 for interference measurement. In certain aspects, the DCI may indicate, to UE 804, that the scheduled PDSCH includes self-contained ZP CSI-IM resources for interference measurement by UE 804. For example, the PDSCH may be rate matched around the activated ZP CSI-IM resources to leave holes for ZP CSI-IM resource transmission within the scheduled downlink data transmission.

In certain aspects, the DCI may further indicate that UE 804 is to measure interference and compute CQI for each activated ZP CSI-IM resource individually. Thus, in certain aspects, UE 804 may report the computed CQI for each ZP CSI-IM resource separately. Further, in certain aspects, UE 804 may report computed CQI for only a subset (e.g., one or more) of the ZP CSI-IM resources measured with an interference below a threshold interference level (e.g., with a low interference level) . Reporting CQI for only a subset of the activated ZP CSI-IM resources may reduce signaling overhead. Further, reporting CQI for only a subset of the activated ZP CSI-IM resources with low interference may reduce noise in the information reported to network entity 802, such that only those ZP CSI-IM resources with low interference and associated with one or more UEs may be considered for MU pairing.

Alternatively, in certain aspects, the DCI may further indicate that UE 804 is to measure total interference among the activated ZP CSI-IM resources and compute CQI based on the total measured interference. In this case, UE 804 may be indicated to report a single CQI.

Process flow 800 proceeds, at 816, with UE 804 receiving a downlink data transmission from network entity 802. The downlink data transmission may be a PDSCH with one or more ZP CSI-IM resources (e.g., a PDSCH rate matched around the ZP CSI-IM resource (s) ) . The ZP CSI-IM resource (s) may be contained within a plurality of resources allocated for the PDSCH.

In certain aspects, a ZP CSI-IM resource contained within the downlink data transmission may overlap with at least one DMRS or tracking reference signal (TRS) resource also contained within the resources allocated for the downlink data channel. UE 804 may assume that this ZP CSI-IM resource is unavailable for interference measurement and reporting given that it overlaps a DMRS or TRS resource. Thus, UE 804 may refrain from performing an interference measurement based on the ZP CSI-IM resource.

In certain aspects, multiple ZP CSI-IM resources are included in the downlink data transmission received by UE 804. Each ZP CSI-IM resource may correspond to a candidate co-scheduled UE. More specifically, each ZP CSI-IM resource, when measured, may represent interference caused by all layers of a candidate co-scheduled UE associated with the respective ZP CSI-IM resource.

Based on receiving the downlink data transmission, process flow 800 proceeds, at 818, with UE 804 performing one or more interference measurements based on the ZP CSI-IM resource (s) included in the downlink data transmission. Further, at 820, UE 804 may compute one or more MU CQIs based on the interference measurement (s) .

As described herein, in certain aspects, UE 804 may measure interference and compute an MU CQI for each ZP CSI-IM resource included in the downlink data transmission separately. In certain aspects, UE 804 may measure interference for each ZP CSI-IM and compute an MU CQI based on a subset of the interference measurements. In certain aspects, UE 804 may measure interference for each ZP CSI-IM and compute an MU CQI based on all of the interference measurements (e.g., the MU CQI may provide a summary of the measured interference) .

In certain aspects, UE 804 may measure interference based on the ZP CSI-IM resource (s) included in the downlink data transmission and determine multiple MU CQIs associated with multiple subbands. For example, UE 804 may determine an MU CQI for a maximum carrier bandwidth or an MU CQI per subband of the maximum carrier bandwidth.

In certain aspects, the downlink data transmissions (e.g., transmitted to UE 804 at 816) may further include one or more DMRS resources. For example, DMRS resource (s) may be contained within the plurality of resources allocated for the downlink data transmission. In this case, the MU CQI (s) determined by UE 804, at 820, may be based on the one or more DMRS resources.

In certain aspects, the MU CQI (s) determined by UE 804, at 820, may be determined for a same rank as the downlink data channel.

In certain aspects, interference measurement (s) , performed at 818 by UE 804, may be based on only the ZP CSI-IM resource (s) contained within the downlink data channel without considering the interference on the other DMRS ports for other co-scheduled UEs (e.g., in cases where UE 804 is co-scheduled with another UE for current MU-MIMO communications from network entity 802) .

Process flow 800 proceeds, at 822, with sending the MU CQI (s) to network entity 802. The MU CQI (s) reported by UE 804 may be valid across resource blocks of the scheduled downlink data transmission.

In certain aspects, UE 804 sends the MU CQI (s) to network entity 802 in an uplink communication comprising a hybrid automatic repeat request (HARQ) acknowledgement (ACK) or a negative ACK (NACK) feedback for the downlink data transmission (e.g., sends the MU CQI (s) together with ACK/NACK feedback) . In certain aspects, UE 804 sends the CQI (s) to network entity 802 via a PUCCH or a PUSCH.

In certain aspects, the MU CQI (s) are the MU CQI (s) determined by UE 804 at 820. For example, the MU CQI (s) may include an MU CQI determined per ZP CSI-IM resource contained within the downlink data transmission or an MU CQI determined for multiple ZP CSI-IM resources (e.g., such as a subset of the ZP CSI-IM resources or all of the ZP CSI-IM resources contained within the downlink data transmission) .

In certain aspects, the MU CQI (s) reported by UE 804 include an MU CQI determined for a maximum carrier bandwidth. In certain aspects, the MU CQI (s) reported by UE 804 include an MU CQI determined for one or more subbands of the maximum carrier bandwidth.

In certain aspects, the MU CQI (s) reported by UE 804 include an indication of a difference between a calculated MU CQI and a CQI associated with a current MCS corresponding to the downlink data transmission (e.g., a delta MU CQI (s) relative to a current MCS) .

In certain aspects, when the MU CQI (s) are sent to network entity 802 via a PUCCH or a PUSCH, additional information may be included in the PUCCH or the PUSCH.

For example, in certain aspects, UE 804 may report an indication ora selection of the ZP CSI-IM resources contained within the downlink data transmission. In some cases, the reported ZP CSI-IM resources may be resources for which measured interference is low. UE 804 may report this selection of ZP CSI-IM resources to aid network entity 802 in determining an MU pair for MU-MIMO communications.

As another example, in certain aspects, UE 804 may report multiple MU CQIs, where each MU CQI corresponds to a different candidate MU pairing. For example, the downlink data transmission received by UE 804, at 816, may include three ZP CSI-IM resources, each corresponding to a different candidate co-scheduled UE (e.g., three UEs which may be paired with UE 804 for MU-MIMO communications) .

At 818, UE 804 may perform a first interference measurement for the first ZP CSI-IM associated with a first candidate co-scheduled UE, perform a second interference measurement for the second ZP CSI-IM associated with the second candidate co-scheduled UE, and perform a third interference measurement for the third ZP CSI-IM associated with the third candidate co-scheduled UE.

At 820, UE 804 may determine a first MU CQI based on the first and second interference measurements, a second MU CQI based on the second and third interference measurements, and a third MU CQI based on the first and third interference measurements. The first MU CQI may represent a channel quality for a candidate MU pairing including UE 804, the first candidate co-scheduled UE, and the third candidate co-scheduled UE. The second MU CQI may represent a channel quality for a candidate MU pairing including UE 804, the second candidate co-scheduled UE, and the third candidate co-scheduled UE. The third MU CQI may represent a channel quality for a candidate MU pairing including UE 804, the first candidate co-scheduled UE, and the third candidate co-scheduled UE. UE 804 may report the first, second, and third MU CQI (s) to network entity 802 at 822.

Process flow 800 proceeds, at 824, with network entity 802 performing one or more actions including determining an MU pairing to use for MU-MIMO communication, switching a current MU pairing, and/or determining MCS (s) for downlink communications.

For example, the MU CQI (s) received by network entity 802 may include a delta MU CQI relative to a current MCS used for downlink communication. Network entity 802 may use the delta MU CQI paired with a previously reported RI/PMI/CQI to update an MCS for a future MU-MIMO transmission.

In certain aspects when the MU CQI (s) reported include an MU CQI per subband, network entity 802 may use the reported MU CQIs to further refine a frequency domain scheduling for MU-MIMO communications. For example, network entity 802 may assign frequency domain resources with low interference levels to a UE targeted for MU pairing for MU-MIMO communication. As another example, network entity 802 may pair a UE targeted for MU pairing with different UEs in the frequency domain.

As illustrated in FIG. 8, introducing ZP CSI-IM resources in the downlink data transmission, transmitted to UE 804 at 814, beneficially enables network entity 802 to evaluate the interference that may be caused by one or more candidate co-scheduled UEs to evaluate various candidate MU pairings, including at least UE 804, for MU-MIMO communication. Accordingly, network entity 802 may be able to determine an MU pairing for MU-MIMO that achieves sufficient network capacity and/or communication reliability, while also reducing interference from MU paired UEs. Further, network entity 802 may be able to determine MCS (s) to use for downlink communications with MU paired UEs for each candidate MU pairing that is evaluated by network entity 802.

FIG. 9 depicts an example downlink data transmission (e.g., a PDSCH) with self-contained ZP CSI-IM resources corresponding to multiple candidate co-scheduled UEs. As shown in FIG. 9, a network entity 902 may be currently using SU-MIMO to communicate with a first UE 904 (1) . To determine an MU pairing, including first UE 904 (1) , for MU-MIMO communication, network entity 902 may send a downlink communication to first UE 904 (1) , at 912, including ZP CSI-IM resources contained within resources allocated for a PDSCH. The ZP CSI-IM resources may be associated with a second UE 904 (2) and a third UE 904 (3) in this example. For example, ZP CSI-IM resources included in a first OFDM symbol of the PDSCH may be associated with second UE 904 (2) and ZP CSI-IM resources included in a third OFDM symbol of the PDSCH may be associated with third UE 904 (3) .

First UE 904 (1) may perform an interference measurement based on one or more of the ZP CSI-IM resources included in the PDSCH to determine one or more MU CQI (s) . In certain aspects, a number of interference measurement (s) and/or a number of MU CQI (s) determined by first UE 904 (1) may be configured at first UE 904 (1) . In certain aspects, network entity 902 may send an indication to first UE 904 (1) indicating a number of interference measurement (s) that first UE 904 (1) is to perform and/or a number of MU CQI (s) that first UE 904 (1) is to report. In certain aspects, first UE 904 (1) may determine itself, the number of interference measurement (s) to perform and/or the number of MU CQI (s) to report.

First UE 904 (1) may report one or more of the determined MU CQI (s) to network entity 902 at 914. In certain aspects, reported MU CQI (s) are MU CQI (s) associated with interference measurement (s) below an interference measurement threshold. In certain aspects, the MU CQI (s) may be included in an uplink communication comprising HARQ ACK/NACK feedback for the PDSCH. Network entity 902 may use this information to determine an MU pairing, such as first UE 904 (1) and second UE 904 (2) or first UE 904 (1) and third UE 904 (3) , to use for MU-MIMO communication and/or an MCS to use for downlink communication assuming the MU pairing is established for MU-MIMO communication.

Example Operations

FIG. 10 shows a method 1000 for wireless communications by an apparatus, such as UE 104 of FIGS. 1 and 3.

Method 1000 begins at block 1005 with receiving a downlink control information that: schedules a first downlink communication comprising a first zero power channel state information interference measurement (ZP CSI-IM) resource associated with a candidate co-scheduled user equipment (UE) and contained within a first plurality of resources allocated for a first downlink data channel and triggers an interference measurement for the first ZP CSI-IM resource

Method 1000 then proceeds at block 1010 with receiving the first downlink communication.

Method 1000 then proceeds to block 1015 with performing the interference measurement based at least in part on the first ZP CSI-IM resource.

Method 1000 then proceeds to block 1020 with sending a multiple user (MU) channel quality indicator (CQI) based at least in part on the interference measurement.

In certain aspects, method 1000 further includes, based at least in part on the MU CQI, receiving a second downlink communication over a second plurality of resources used to simultaneously communicate a third downlink communication to the candidate co-scheduled UE.

In certain aspects, method 1000 further includes receiving a configuration for the first ZP CSI-IM resource.

In certain aspects, the configuration comprises an indication of a frequency occupancy of the first ZP CSI-IM resource within a frequency associated with the first plurality of resources allocated for the first downlink data channel.

In certain aspects, the configuration comprises an indication of a starting symbol of (e.g., a symbol location for) the first ZP CSI-IM resource within a slot, and the method 1000 further comprises performing the interference measurement based at least in part on a first symbol of the first plurality of resources allocated for the first downlink data channel instead of the starting symbol indicated in the configuration. For example, the starting symbol of the first ZP CSI-IM resource, for the interference measurement, may be re-interpreted as the location of a first OFDM symbol of the scheduled first downlink data channel including the first ZP CSI-IM resource.

In certain aspects, the DCI further comprises an indication that the first ZP CSI-IM resource is scheduled in the first downlink communication.

In certain aspects, method 1000 further includes receiving a second downlink communication comprising a second ZP CSI-IM resource associated with at least the candidate co-scheduled UE and at least one DMRS resource or TRS resource contained within a second plurality of resources allocated for a second downlink data channel, wherein the second ZP CSI-IM resource overlaps the DMRS resource or the TRS resource.

In certain aspects, method 1000 further includes refraining from performing a second interference measurement based at least in part on the second ZP CSI-IM resource overlapping the DMRS resource or the TRS resource.

In certain aspects, the first downlink communication comprises a plurality of first ZP CSI-IM resources associated with a plurality of candidate co-scheduled UEs.

In certain aspects, block 1010 includes: for each respective candidate co-schedule UE of the plurality of candidate co-scheduled UEs, performing a UE-specific interference measurement based at least in part on at least one first ZP CSI-IM resource of the plurality of first ZP CSI-IM resources associated with the respective candidate co-scheduled UE to determine a UE-specific CQI; and block 1020 includes sending: the UE-specific CQI determined for one or more candidate co-scheduled UEs of the plurality of candidate co-scheduled UEs; or a first summary of the UE-specific CQI determined for the one or more candidate co-scheduled UEs.

In certain aspects, method 1000 further includes sending the UE-specific CQI determined for the one or more candidate co-scheduled UEs of the plurality of candidate co-scheduled UEs, wherein the UE-specific interference measurement associated with each of the one or more of the UE-specific CQIs is below an interference measurement threshold.

In certain aspects, block 1020 includes sending the MU CQI in an uplink communication comprising a HARQ ACK or a NACK feedback for the first downlink communication.

In certain aspects, the first downlink communication further comprises at least one DMRS resource contained within the first plurality of resources allocated for the first downlink data channel; and the MU CQI is based at least in part on the DMRS resource.

In certain aspects, the MU CQI is determined for a rank of the first downlink data channel.

In certain aspects, the MU CQI comprises an indication of a difference between the MU CQI and a CQI associated with a current modulation and coding scheme corresponding to the first downlink communication.

In certain aspects, block 1020 includes sending the MU CQI via a PUCCH or a PUSCH.

In certain aspects, the first downlink communication comprises a plurality of first ZP CSI-IM resources associated with a plurality of candidate co-scheduled UEs contained within the first plurality of resources allocated for the first downlink data channel, and the method 1000 further comprises sending an indication of a subset of the plurality of first ZP CSI-IM resources associated with a subset of the plurality of candidate co-scheduled UEs to pair for an MU multiple-input-multiple-output operation.

In certain aspects, the MU CQI is associated with a maximum carrier bandwidth or a subband of the maximum carrier bandwidth.

In certain aspects, method 1000, or any aspect related to it, may be performed by an apparatus, such as communications device 1200 of FIG. 12, which includes various components operable, configured, or adapted to perform the method 1000. Communications device 1200 is described below in further detail.

Note that FIG. 10 is just one example of a method, and other methods including fewer, additional, or alternative operations are possible consistent with this disclosure.

FIG. 11 shows a method 1100 for wireless communications by an apparatus, such as BS 102 of FIGS. 1 and 3, or a disaggregated base station as discussed with respect to FIG. 2.

Method 1100 begins at block 1105 with sending a DCI that: schedules a first downlink communication for a UE, the first downlink communication comprising a first zero power channel state information interference measurement (ZP CSI-IM) resource associated with a candidate co-scheduled UE and contained within a first plurality of resources allocated for a first downlink data channel, and triggers an interference measurement for the first ZP CSI-IM resource.

Method 1100 then proceeds to block 1110 with sending the first downlink communication.

Method 1100 then proceeds to block 1115 with receiving an MU CQI based at least in part on the first downlink communication.

In certain aspects, method 1100 further includes, based at least in part on the MU CQI, determining an MU MIMO pairing including the UE and the candidate co-scheduled UE.

In certain aspects, method 1100 further includes, based at least in part on the MU CQI, determining a first modulation and coding scheme (MCS) for subsequent downlink multiple-input-multiple-output communications with the UE.

In certain aspects, method 1100 further includes, sending, to the UE using the first MCS, a second downlink communication over a second plurality of resources used to simultaneously communicate a third downlink communication to the candidate co-scheduled UE.

In certain aspects, method 1100 further includes, based at least in part on the MU CQI, determining a second MCS for subsequent downlink multiple-input-multiple-output communications with the candidate co-scheduled UE.

In certain aspects, method 1100 further includes sending a configuration for the first ZP CSI-IM resource.

In certain aspects, the configuration comprises an indication of a starting symbol of the first ZP CSI-IM resource within a slot.

In certain aspects, method 1100 further includes sending a second downlink communication comprising a second ZP CSI-IM resource associated with at least the candidate co-scheduled UE and at least one DMRS resource or TRS resource contained within a second plurality of resources allocated for a second downlink data channel, wherein the second ZP CSI-IM resource overlaps the DMRS resource or the TRS resource.

In certain aspects, block 1115 includes receiving: UE-specific CQI determined for one or more candidate co-scheduled UEs of the plurality of candidate co-scheduled UEs; or a first summary of the UE-specific CQI determined for the one or more candidate co-scheduled UEs.

In certain aspects, block 1115 includes receiving the MU CQI in an uplink communication comprising a HARQ ACK or a NACK feedback for the first downlink communication.

In certain aspects, block 1115 includes receiving the MU CQI via a PUCCH or a PUSCH.

In certain aspects, the first downlink communication comprises a plurality of first ZP CSI-IM resources associated with a plurality of candidate co-scheduled UEs contained within the first plurality of resources allocated for the first downlink data channel, and the method 1100 further comprises receiving an indication ora subset of the plurality of first ZP CSI-IM resources associated with a subset of the plurality of candidate co-scheduled UEs to pair for the MU multiple-input-multiple-output pairing.

In certain aspects, wherein the MU CQI is associated with a maximum carrier bandwidth or a subband of the maximum carrier bandwidth.

In certain aspects, method 1100, or any aspect related to it, may be performed by an apparatus, such as communications device 1300 of FIG. 13, which includes various components operable, configured, or adapted to perform the method 1100. Communications device 1300 is described below in further detail.

Note that FIG. 11 is just one example of a method, and other methods including fewer, additional, or alternative operations are possible consistent with this disclosure.

Example Communications Devices

FIG. 12 depicts aspects of an example communications device 1200. In some aspects, communications device 1200 is a user equipment, such as UE 104 described above with respect to FIGS. 1 and 3.

The communications device 1200 includes a processing system 1205 coupled to a transceiver 1265 (e.g., a transmitter and/or a receiver) . The transceiver 1265 is configured to transmit and receive signals for the communications device 1200 via an antenna 1270, such as the various signals as described herein. The processing system 1205 may be configured to perform processing functions for the communications device 1200, including processing signals received and/or to be transmitted by the communications device 1200.

The processing system 1205 includes one or more processors 1210. In various aspects, the one or more processors 1210 may be representative of one or more of receive processor 358, transmit processor 364, TX MIMO processor 366, and/or controller/processor 380, as described with respect to FIG. 3. The one or more processors 1210 are coupled to a computer-readable medium/memory 1235 via a bus 1260. In certain aspects, the computer-readable medium/memory 1235 is configured to store instructions (e.g., computer-executable code) that when executed by the one or more processors 1210, enable and cause the one or more processors 1210 to perform the method 1000 described with respect to FIG. 10, or any aspect related to it, including any operations described in relation to FIG. 10. Note that reference to a processor performing a function of communications device 1200 may include one or more processors performing that function of communications device 1200, such as in a distributed fashion.

In the depicted example, computer-readable medium/memory 1235 stores code for receiving 1240, code for performing 1245, code for sending 1250, and code for refraining 1255. Processing of the code 1240-1255 may enable and cause the communications device 1200 to perform the method 1000 described with respect to FIG. 10, or any aspect related to it.

The one or more processors 1210 include circuitry configured to implement (e.g., execute) the code stored in the computer-readable medium/memory 1235, including circuitry for receiving 1215, circuitry for performing 1220, circuitry for sending 1225, and circuitry for refraining 1230. Processing with circuitry 1215-1230 may enable and cause the communications device 1200 to perform the method 1000 described with respect to FIG. 10, or any aspect related to it.

More generally, means for communicating, transmitting, sending or outputting for transmission may include the transceivers 354, antenna (s) 352, transmit processor 364, TX MIMO processor 366, AI processor 370, and/or controller/processor 380 of the UE 104 illustrated in FIG. 3, transceiver 1265 and/or antenna 1270 of the communications device 1200 in FIG. 12, and/or one or more processors 1210 of the communications device 1200 in FIG. 12. Means for communicating, receiving or obtaining may include the transceivers 354, antenna (s) 352, receive processor 358, AI processor 370, and/or controller/processor 380 of the UE 104 illustrated in FIG. 3, transceiver 1265 and/or antenna 1270 of the communications device 1200 in FIG. 12, and/or one or more processors 1210 of the communications device 1200 in FIG. 12.

FIG. 13 depicts aspects of an example communications device 1300. In some aspects, communications device 1300 is a network entity, such as B S 102 of FIGS. 1 and 3, or a disaggregated base station as discussed with respect to FIG. 2.

The communications device 1300 includes a processing system 1305 coupled to a transceiver 1355 (e.g., a transmitter and/or a receiver) and/or a network interface 1365. The transceiver 1355 is configured to transmit and receive signals for the communications device 1300 via an antenna 1360, such as the various signals as described herein. The network interface 1365 is configured to obtain and send signals for the communications device 1300 via communications link (s) , such as a backhaul link, midhaul link, and/or fronthaul link as described herein, such as with respect to FIG. 2. The processing system 1305 may be configured to perform processing functions for the communications device 1300, including processing signals received and/or to be transmitted by the communications device 1300.

The processing system 1305 includes one or more processors 1310. In various aspects, one or more processors 1310 may be representative of one or more of receive processor 338, transmit processor 320, TX MIMO processor 330, and/or controller/processor 340, as described with respect to FIG. 3. The one or more processors 1310 are coupled to a computer-readable medium/memory 1330 via a bus 1350. In certain aspects, the computer-readable medium/memory 1330 is configured to store instructions (e.g., computer-executable code) that when executed by the one or more processors 1310, enable and cause the one or more processors 1310 to perform the method 1100 described with respect to FIG. 11, or any aspect related to it, including any operations described in relation to FIG. 11. Note that reference to a processor of communications device 1300 performing a function may include one or more processors of communications device 1300 performing that function, such as in a distributed fashion.

In the depicted example, the computer-readable medium/memory 1330 stores code for sending 1335, code for receiving 1340, and code for determining 1345. Processing of the code 1335-1345 may enable and cause the communications device 1300 to perform the method 1100 described with respect to FIG. 11, or any aspect related to it.

The one or more processors 1310 include circuitry configured to implement (e.g., execute) the code stored in the computer-readable medium/memory 1330, including circuitry for sending 1315, circuitry for receiving 1320, and circuitry for determining 1325. Processing with circuitry 1315-1325 may enable and cause the communications device 1300 to perform the method 1100 described with respect to FIG. 11, or any aspect related to it.

More generally, means for communicating, transmitting, sending or outputting for transmission may include the transceivers 332, antenna (s) 334, transmit processor 320, TX MIMO processor 330, AI processor 318, and/or controller/processor 340 of the BS 102 illustrated in FIG. 3, transceiver 1355, antenna 1360, and/or network interface 1365 of the communications device 1300 in FIG. 13, and/or one or more processors 1310 of the communications device 1300 in FIG. 13. Means for communicating, receiving or obtaining may include the transceivers 332, antenna (s) 334, receive processor 338, AI processor 318, and/or controller/processor 340 of the BS 102 illustrated in FIG. 3, transceiver 1355, antenna 1360, and/or network interface 1365 of the communications device 1300 in FIG. 13, and/or one or more processors 1310 of the communications device 1300 in FIG. 13.

Example Clauses

Implementation examples are described in the following numbered clauses:

Clause 1: A method for wireless communications by an apparatus comprising: receiving a downlink control information (DCI) that: schedules a first downlink communication comprising a first zero power channel state information interference measurement (ZP CSI-IM) resource associated with a candidate co-scheduled user equipment (UE) and contained within a first plurality of resources allocated for a first downlink data channel, and triggers an interference measurement for the first ZP CSI-IM resource; receiving the first downlink communication; performing the interference measurement based at least in part on the first ZP CSI-IM resource; and sending a multiple user (MU) channel quality indicator (CQI) based at least in part on the interference measurement.

Clause 2: The method of Clause 1, further comprising, based at least in part on the MU CQI, receiving a second downlink communication over a second plurality of resources used to simultaneously communicate a third downlink communication to the candidate co-scheduled UE.

Clause 3: The method of any one of Clauses 1-2, further comprising receiving a configuration for the first ZP CSI-IM resource.

Clause 4: The method of Clause 3, wherein: the configuration comprises an indication of a frequency occupancy of the first ZP CSI-IM resource within a frequency associated with the first plurality of resources allocated for the first downlink data channel.

Clause 5: The method of any one of Clauses 3-4, wherein: the configuration comprises an indication of a starting symbol of the first ZP CSI-IM resource within a slot, and the method further comprises performing the interference measurement based at least in part on a first symbol of the first plurality of resources allocated for the first downlink data channel instead of the starting symbol.

Clause 6: The method of any one of Clauses 1-5, wherein the DCI further comprises an indication that the first ZP CSI-IM resource is scheduled in the first downlink communication.

Clause 7: The method of any one of Clauses 1-6, further comprising: receiving a second downlink communication comprising a second ZP CSI-IM resource associated with at least the candidate co-scheduled UE and at least one DMRS resource or TRS resource contained within a second plurality of resources allocated for a second downlink data channel, wherein the second ZP CSI-IM resource overlaps the DMRS resource or the TRS resource; and refraining from performing a second interference measurement based at least in part on the second ZP CSI-IM resource overlapping the DMRS resource or the TRS resource.

Clause 8: The method of any one of Clauses 1-7, wherein the first downlink communication comprises a plurality of first ZP CSI-IM resources associated with a plurality of candidate co-scheduled UEs.

Clause 9: The method of Clause 8, wherein: performing the interference measurement based at least in part on the first ZP CSI-IM resource comprises: for each respective candidate co-scheduled UE of the plurality of candidate co-scheduled UEs, performing a UE-specific interference measurement based at least in part on at least one first ZP CSI-IM resource of the plurality of first ZP CSI-IM resources associated with the respective candidate co-scheduled UE to determine a UE-specific CQI; and sending the CQI comprises sending: the UE-specific CQI determined for one or more candidate co-scheduled UEs of the plurality of candidate co-scheduled UEs; or a first summary of the UE-specific CQI determined for the one or more candidate co-scheduled UEs.

Clause 10: The method of Clause 9, further comprising sending the UE-specific CQI determined for the one or more candidate co-scheduled UEs of the plurality of candidate co-scheduled UEs, wherein the UE-specific interference measurement associated with each of the one or more of the UE-specific CQIs is below an interference measurement threshold.

Clause 11: The method of any one of Clauses 1-10, further comprising sending the MU CQI in an uplink communication comprising a HARQ ACK or a NACK feedback for the first downlink communication.

Clause 12: The method of any one of Clauses 1-11, wherein: the first downlink communication further comprises at least one DMRS resource contained within the first plurality of resources allocated for the first downlink data channel; and the MU CQI is based at least in part on the DMRS resource.

Clause 13: The method of any one of Clauses 1-12, wherein the MU CQI is determined for a rank of the first downlink data channel.

Clause 14: The method of any one of Clauses 1-13, wherein the MU CQI comprises an indication of a difference between the MU CQI and a CQI associated with a current modulation and coding scheme corresponding to the first downlink communication.

Clause 15: The method of any one of Clauses 1-14, further comprising sending the MU CQI via a PUCCH or a PUSCH.

Clause 16: The method of any one of Clauses 1-15, wherein: the first downlink communication comprises a plurality of first ZP CSI-IM resources associated with a plurality of candidate co-scheduled UEs contained within the first plurality of resources allocated for the first downlink data channel, and the method further comprises sending an indication of a subset of the plurality of first ZP CSI-IM resources associated with a subset of the plurality of candidate co-scheduled UEs to pair for an MU multiple-input-multiple-output operation.

Clause 17: The method of any one of Clauses 1-16, wherein the MU CQI is associated with a maximum carrier bandwidth or a subband of the maximum carrier bandwidth.

Clause 18: A method for wireless communications by an apparatus comprising: sending a DCI that: schedules a first downlink communication for a UE, the first downlink communication comprising a first zero power channel state information interference measurement (ZP CSI-IM) resource associated with a candidate co- scheduled UE and contained within a first plurality of resources allocated for a first downlink data channel, and triggers an interference measurement for the first ZP CSI-IM resource; sending the first downlink communication; and receiving an MU CQI based at least in part on the first downlink communication.

Clause 19: The method of Clause 18, further comprising, based at least in part on the MU CQI, determining: an MU multiple-input-multiple-output pairing including the UE and the candidate co-scheduled UE; and a first modulation and coding scheme (MCS) for subsequent downlink multiple-input-multiple-output communications with the UE;and sending, to the UE using the first MCS, a second downlink communication over a second plurality of resources used to simultaneously communicate a third downlink communication to the candidate co-scheduled UE.

Clause 20: The method of Clause 19, further comprising, based at least in part on the MU CQI, determine a second MCS for subsequent downlink multiple-input-multiple-output communications with the candidate co-scheduled UE.

Clause 21: The method of any one of Clause 18-20, further comprising sending a configuration for the first ZP CSI-IM resource.

Clause 22: The method of Clause 21, wherein the configuration comprises an indication of a frequency occupancy of the first ZP CSI-IM resource within a frequency associated with the first plurality of resources allocated for the first downlink data channel.

Clause 23: The method of any one of Clauses 21-22, wherein the configuration comprises an indication of a starting symbol of the first ZP CSI-IM resource within a slot.

Clause 24: The method of any one of Clauses 18-23, wherein, based at least in part on the MU CQI, the apparatus determines the MU multi-input-multiple-output pairing including the UE and the candidate co-scheduled UE; and the method further comprises sending, to the UE, a second downlink communication over a second plurality of resources used to simultaneously communicate a third downlink communication to the candidate co-scheduled UE.

Clause 25: The method of any one of Clauses 18-24, wherein the DCI further comprises an indication that the first ZP CSI-IM resource is scheduled in the first downlink communication.

Clause 26: The method of any one of Clauses 18-25, further comprising: sending a second downlink communication comprising a second ZP CSI-IM resource associated with at least the candidate co-scheduled UE and at least one DMRS resource or TRS resource contained within a second plurality of resources allocated for a second downlink data channel, wherein the second ZP CSI-IM resource overlaps the DMRS resource or the TRS resource.

Clause 27: The method of any one of Clauses 18-26, wherein the first downlink communication comprises a plurality of first ZP CSI-IM resources associated with a plurality of candidate co-scheduled UEs.

Clause 28: The method of Clause 27, wherein: receiving the MU CQI comprises receiving: UE-specific CQI determined for one or more candidate co-scheduled UEs of the plurality of candidate co-scheduled UEs; or a first summary of the UE-specific CQI determined for the one or more candidate co-scheduled UEs.

Clause 29: The method of any one of Clauses 18-28, wherein receiving the MU CQI comprises receiving the MU CQI in an uplink communication comprising a HARQ ACK or a NACK feedback for the first downlink communication.

Clause 30: The method of any one of Clauses 18-29, wherein: the first downlink communication further comprises at least one DMRS resource contained within the first plurality of resources allocated for the first downlink data channel; and the MU CQI is based at least in part on the DMRS resource.

Clause 31: The method of any one of Clauses 18-30, wherein the MU CQI is determined for a rank of the first downlink data channel.

Clause 32: The method of any one of Clauses 18-31, wherein the MU CQI comprises an indication of a difference between the MU CQI and a CQI associated with a current MCS corresponding to the first downlink communication.

Clause 33: The method of any one of Clauses 18-32, wherein receiving the MU CQI comprises receiving the MU CQI via a PUCCH or a PUSCH.

Clause 34: The method of any one of Clauses 18-33, wherein: the first downlink communication comprises a plurality of first ZP CSI-IM resources associated with a plurality of candidate co-scheduled UEs contained within the first plurality of resources allocated for the first downlink data channel, and the method further comprises receiving an indication of a subset of the plurality of first ZP CSI-IM resources associated with a subset of the plurality of candidate co-scheduled UEs to pair for the MU multiple-input-multiple-output pairing.

Clause 35: The method of any one of Clauses 18-34, wherein the MU CQI is associated with a maximum carrier bandwidth or a subband of the maximum carrier bandwidth.

Clause 36: One or more apparatuses, comprising: one or more memories comprising executable instructions; and one or more processors configured to execute the executable instructions and cause the one or more apparatuses to perform a method in accordance with any one of Clauses 1-35.

Clause 37: One or more apparatuses, comprising: one or more memories; and one or more processors, coupled to the one or more memories, configured to cause the one or more apparatuses to perform a method in accordance with any one of Clauses 1-35.

Clause 38: One or more apparatuses, comprising: one or more memories; and one or more processors, coupled to the one or more memories, configured to perform a method in accordance with any one of Clauses 1-35.

Clause 39: One or more apparatuses, comprising means for performing a method in accordance with any one of Clauses 1-35.

Clause 40: One or more non-transitory computer-readable media comprising executable instructions that, when executed by one or more processors of one or more apparatuses, cause the one or more apparatuses to perform a method in accordance with any one of Clauses 1-35.

Clause 41: One or more computer program products embodied on one or more computer-readable storage media comprising code for performing a method in accordance with any one of Clauses 1-35.

Clause 42: A user equipment (UE) , comprising: a processing system that includes processor circuitry and memory circuitry that stores code and is coupled with the processor circuitry, the processing system configured to cause the UE to perform a method in accordance with any one of Clauses 1-17.

Clause 43: A network entity, comprising: a processing system that includes processor circuitry and memory circuitry that stores code and is coupled with the processor circuitry, the processing system configured to cause the network entity to perform a method in accordance with any one of Clauses 18-35.

Additional Considerations

The preceding description is provided to enable any person skilled in the art to practice the various aspects described herein. The examples discussed herein are not limiting of the scope, applicability, or aspects set forth in the claims. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. For example, changes may be made in the function and arrangement of elements discussed without departing from the scope of the disclosure. Various examples may omit, substitute, or add various procedures or components as appropriate. For instance, the methods described may be performed in an order different from that described, and various actions may be added, omitted, or combined. Also, features described with respect to some examples may be combined in some other examples. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, the scope of the disclosure is intended to cover such an apparatus or method that is practiced using other structure, functionality, or structure and functionality in addition to, or other than, the various aspects of the disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim.

The various illustrative logical blocks, modules and circuits described in connection with the present disclosure may be implemented or performed with a general purpose processor, an AI processor, a digital signal processor (DSP) , an ASIC, a field programmable gate array (FPGA) or other programmable logic device (PLD) , discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any commercially available processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination ofa DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, a system on a chip (SoC) , or any other such configuration.

As used herein, a phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combination with multiples of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c) .

As used herein, the term “determining” encompasses a wide variety of actions. For example, “determining” may include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure) , ascertaining and the like. Also, “determining” may include receiving (e.g., receiving information) , accessing (e.g., accessing data in a memory) and the like. Also, “determining” may include resolving, selecting, choosing, establishing and the like.

As used herein, “coupled to” and “coupled with” generally encompass direct coupling and indirect coupling (e.g., including intermediary coupled aspects) unless stated otherwise. For example, stating that a processor is coupled to a memory allows for a direct coupling or a coupling via an intermediary aspect, such as a bus.

The methods disclosed herein comprise one or more actions for achieving the methods. The method actions may be interchanged with one another without departing from the scope of the claims. In other words, unless a specific order of actions is specified, the order and/or use of specific actions may be modified without departing from the scope of the claims. Further, the various operations of methods described above may be performed by any suitable means capable of performing the corresponding functions. The means may include various hardware and/or software component (s) and/or module (s) , including, but not limited to a circuit, an application specific integrated circuit (ASIC) , or processor.

The following claims are not intended to be limited to the aspects shown herein, but are to be accorded the full scope consistent with the language of the claims. Reference to an element in the singular is not intended to mean only one unless specifically so stated, but rather “one or more. ” The subsequent use of a definite article (e.g., “the” or “said” ) with an element (e.g., “the processor” ) is not intended to invoke a singular meaning (e.g., “only one” ) on the element unless otherwise specifically stated. For example, reference to an element (e.g., “a processor, ” “a controller, ” “a memory, ” “a transceiver, ” “an antenna, ” “the processor, ” “the controller, ” “the memory, ” “the transceiver, ” “the antenna, ” etc. ) , unless otherwise specifically stated, should be understood to refer to one or more elements (e.g., “one or more processors, ” “one or more controllers, ” “one or more memories, ” “one more transceivers, ” etc. ) . The terms “set” and “group” are intended to include one or more elements, and may be used interchangeably with “one or more. ” Where reference is made to one or more elements performing functions (e.g., steps of a method) , one element may perform all functions, or more than one element may collectively perform the functions. When more than one element collectively performs the functions, each function need not be performed by each of those elements (e.g., different functions may be performed by different elements) and/or each function need not be performed in whole by only one element (e.g., different elements may perform different sub-functions of a function) . Similarly, where reference is made to one or more elements configured to cause another element (e.g., an apparatus) to perform functions, one element may be configured to cause the other element to perform all functions, or more than one element may collectively be configured to cause the other element to perform the functions. Unless specificaily stated otherwise, the term “some” refers to one or more. All structurai and functionai equivaients to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims.

Claims

An apparatus configured for wireless communications, comprising:

one or more memories; and

one or more processors coupled to the one or more memories, the one or more processors being configured to cause the apparatus to:

receive a downlink control information (DCI) that:

schedules a first downlink communication comprising a first zero power channel state information interference measurement (ZP CSI-IM) resource associated with a candidate co-scheduled user equipment (UE) and contained within a first plurality of resources allocated for a first downlink data channel, and

triggers an interference measurement for the first ZP CSI-IM resource;

receive the first downlink communication;

perform the interference measurement based at least in part on the first ZP CSI-IM resource; and

send a multiple user (MU) channel quality indicator (CQI) based at least in part on the interference measurement.
The apparatus of Claim 1, wherein the one or more processors are configured to cause the apparatus to, based at least in part on the MU CQI, receive a second downlink communication over a second plurality of resources used to simultaneously communicate a third downlink communication to the candidate co-scheduled UE.
The apparatus of Claim 1, wherein the one or more processors are configured to cause the apparatus to receive a configuration for the first ZP CSI-IM resource.
The apparatus of Claim 3, wherein the configuration comprises an indication of a frequency occupancy of the first ZP CSI-IM resource within a frequency associated with the first plurality of resources allocated for the first downlink data channel.
The apparatus of Claim 3, wherein:

the configuration comprises an indication of a starting symbol of the first ZP CSI-IM resource within a slot, and

the one or more processors are configured to cause the apparatus to perform the interference measurement based at least in part on a first symbol of the first plurality of resources allocated for the first downlink data channel instead of the starting symbol.
The apparatus of Claim 1, wherein the DCI further comprises an indication that the first ZP CSI-IM resource is scheduled in the first downlink communication.
The apparatus of Claim 1, wherein the one or more processors are further configured to cause the apparatus to:

receive a second downlink communication comprising a second ZP CSI-IM resource associated with at least the candidate co-scheduled UE and at least one demodulation reference signal (DMRS) resource or tracking reference signal (TRS) resource contained within a second plurality of resources allocated for a second downlink data channel, wherein the second ZP CSI-IM resource overlaps the DMRS resource or the TRS resource; and

refrain from performing a second interference measurement based at least in a part on the second ZP CSI-IM resource overlapping the DMRS resource or the TRS resource.
The apparatus of Claim 1, wherein the first downlink communication comprises a plurality of first ZP CSI-IM resources associated with a plurality of candidate co-scheduled UEs.
The apparatus of Claim 8, wherein:

to perform the interference measurement based at least in part on the first ZP CSI-IM resource, the one or more processors are configured to cause the apparatus to:

for each respective candidate co-scheduled UE of the plurality of candidate co-scheduled UEs, perform a UE-specific interference measurement based at least in part on at least one first ZP CSI-IM resource of the plurality of first ZP CSI-IM resources associated with the respective candidate co-scheduled UE to determine a UE-specific CQI; and

to send the MU CQI, the one or more processors are configured to cause the apparatus to send:

the UE-specific CQI determined for one or more candidate co-scheduled UEs of the plurality of candidate co-scheduled UEs; or

a first summary of the UE-specific CQI determined for the one or more candidate co-scheduled UEs.
The apparatus of Claim 9, wherein:

the one or more processors are configured to cause the apparatus to send the UE-specific CQI determined for the one or more candidate co-scheduled UEs of the plurality of candidate co-scheduled UEs, and

the UE-specific interference measurement associated with each of the one or more of the UE-specific CQIs is below an interference measurement threshold.
The apparatus of Claim 1, wherein the one or more processors are configured to cause the apparatus to send the MU CQI in an uplink communication comprising a hybrid automatic repeat request (HARQ) acknowledgement (ACK) or a negative ACK (NACK) feedback for the first downlink communication.
The apparatus of Claim 1, wherein:

the first downlink communication further comprises at least one DMRS resource contained within the first plurality of resources allocated for the first downlink data channel; and

the MU CQI is based at least in part on the DMRS resource.
The apparatus of Claim 1, wherein the MU CQI comprises an indication of a difference between the MU CQI and a CQI associated with a current modulation and coding scheme corresponding to the first downlink communication.
The apparatus of Claim 1, wherein:

the first downlink communication comprises a plurality of first ZP CSI-IM resources associated with a plurality of candidate co-scheduled UEs contained within the first plurality of resources allocated for the first downlink data channel; and

the one or more processors are further configured to cause the apparatus to send an indication of a subset of the plurality of first ZP CSI-IM resources associated with a subset of the plurality of candidate co-scheduled UEs to pair for a multiple user multiple-input-multiple-output operation.
The apparatus of Claim 1, wherein the MU CQI is associated with a maximum carrier bandwidth or a subband of the maximum carrier bandwidth.
An apparatus configured for wireless communications, comprising:

one or more memories; and

one or more processors coupled to the one or more memories, the one or more processors being configured to cause the apparatus to:

send a downlink control information (DCI) that:

schedules a first downlink communication for a user equipment (UE) , the first downlink communication comprising a first zero power channel state information interference measurement (ZP CSI-IM) resource associated with a candidate co-scheduled UE and contained within a first plurality of resources allocated for a first downlink data channel, and

triggers an interference measurement for the first ZP CSI-IM resource;

send the first downlink communication; and

receive a multiple user (MU) channel quality indicator (CQI) based at least in part on the first downlink communication.
The apparatus of Claim 16, wherein the one or more processors are configured to cause the apparatus to:

based at least in part on the MU CQI, determine:

an MU multiple-input-multiple-output pairing including the UE and the candidate co-scheduled UE; and

a first modulation and coding scheme (MCS) for subsequent downlink multiple-input-multiple-output communications with the UE; and

send, to the UE using the first MCS, a second downlink communication over a second plurality of resources used to simultaneously communicate a third downlink communication to the candidate co-scheduled UE.
The apparatus of Claim 17, wherein the one or more processors are configured to cause the apparatus to, based at least in part on the MU CQI, determine a second MCS for subsequent downlink multiple-input-multiple-output communications with the candidate co-scheduled UE.
The apparatus of Claim 16, wherein the one or more processors are configured to cause the apparatus to send a configuration for the first ZP CSI-IM resource.
A method for wireless communications by an apparatus comprising:

receiving a downlink control information (DCI) that:

schedules a first downlink communication comprising a first zero power channel state information interference measurement (ZP CSI-IM) resource associated with a candidate co-scheduled user equipment (UE) and contained within a first plurality of resources allocated for a first downlink data channel, and

triggers an interference measurement for the first ZP CSI-IM resource receiving the first downlink communication;

performing the interference measurement based at least in part on the first ZP CSI-IM resource; and

sending a multiple user (MU) channel quality indicator (CQI) based at least in part on the interference measurement.