WO2020063434A1

WO2020063434A1 - Csi reporting without full csi-rs presence

Info

Publication number: WO2020063434A1
Application number: PCT/CN2019/106600
Authority: WO
Inventors: Chenxi HAO; Yu Zhang; Peter Gaal; Wanshi Chen
Original assignee: Qualcomm Incorporated
Priority date: 2018-09-26
Filing date: 2019-09-19
Publication date: 2020-04-02
Also published as: WO2020061840A1

Abstract

Certain aspects of the present disclosure provide techniques for CSI reporting without full channel state information reference signal (CSI-RS) presence in a subband. A method generally receiving channel state information (CSI) reporting configuration information configuring the UE to perform CSI measurement and reporting, based on one or more CSI reference signals (CSI-RSs), in one or more subbands (SBs) of a bandwidth part (BWP) of a system bandwidth, determining if a first SB of the one or more SBs includes a valid CSI-RS presence based on whether one or more threshold conditions, involving CSI-RS resources included in the first SB, are satisfied, and transmitting a CSI report corresponding to the first SB if it is determined that the first SB includes a valid CSI-RS presence.

Description

CSI REPORTING WITHOUT FULL CSI-RS PRESENCE

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to PCT Application No. PCT/CN2018/107701, filed September 26, 2018, which is assigned to the assignee hereof and hereby expressly incorporated by reference herein in its entirety as if fully set forth below and for all applicable purposes.

Field of the Disclosure

Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for channel state information (CSI) reporting without full CSI reference signal presence in a subband.

Description of Related Art

Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcasts, etc. These wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc. ) . Examples of such multiple-access systems include 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) systems, LTE Advanced (LTE-A) systems, code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems, to name a few.

In some examples, a wireless multiple-access communication system may include a number of base stations (BSs) , which are each capable of simultaneously supporting communication for multiple communication devices, otherwise known as user equipments (UEs) . In an LTE or LTE-A network, a set of one or more base stations may define an eNodeB (eNB) . In other examples (e.g., in a next generation, a new radio (NR) , or 5G network) , a wireless multiple access communication system may include a number of distributed units (DUs) (e.g., edge units (EUs) , edge nodes (ENs) , radio heads (RHs) , smart radio heads (SRHs) , transmission reception points (TRPs) , etc. ) in communication with a number of central units (CUs) (e.g., central nodes (CNs) , access node controllers (ANCs) , etc. ) , where a set of one or more distributed units, in communication with a central unit, may define an access node (e.g., which may be referred to as a base station, 5G NB, next generation NodeB (gNB or gNodeB) , TRP, etc. ) . A base station or distributed unit may communicate with a set of UEs on downlink channels (e.g., for transmissions from a base station or to a UE) and uplink channels (e.g., for transmissions from a UE to a base station or distributed unit) .

These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. New Radio (NR) (e.g., 5G) is an example of an emerging telecommunication standard. NR is a set of enhancements to the LTE mobile standard promulgated by 3GPP. It is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using OFDMA with a cyclic prefix (CP) on the downlink (DL) and on the uplink (UL) . To these ends, NR supports beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

However, as the demand for mobile broadband access continues to increase, there exists a need for further improvements in NR and LTE technology. Preferably, these improvements should be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.

BRIEF SUMMARY

The systems, methods, and devices of the disclosure each have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of this disclosure as expressed by the claims which follow, some features will now be discussed briefly. After considering this discussion, and particularly after reading the section entitled “Detailed Description” one will understand how the features of this disclosure provide advantages that include improved communications between access points and stations in a wireless network.

Certain aspects provide a method for wireless communications in a network by a user equipment (UE) . The method generally includes receiving channel state information (CSI) reporting configuration information configuring the UE to perform CSI measurement and reporting, based on one or more CSI reference signals (CSI-RSs) , in one or more subbands (SBs) of a bandwidth part (BWP) of a system bandwidth, determining if a first SB of the one or more SBs includes a valid CSI-RS presence based on whether one or more threshold conditions, involving CSI-RS resources included in the first SB, are satisfied, and transmitting a CSI report corresponding to the first SB if it is determined that the first SB includes a valid CSI-RS presence.

Certain aspects provide an apparatus for wireless communications in a network by a user equipment (UE) . The apparatus generally includes at least one processor configured to receive channel state information (CSI) reporting configuration information configuring the UE to perform CSI measurement and reporting, based on one or more CSI reference signals (CSI-RSs) , in one or more subbands (SBs) of a bandwidth part (BWP) of a system bandwidth, determine if a first SB of the one or more SBs includes a valid CSI-RS presence based on whether one or more threshold conditions, involving CSI-RS resources included in the first SB, are satisfied, and transmit a CSI report corresponding to the first SB if it is determined that the first SB includes a valid CSI-RS presence. The apparatus also generally includes a memory coupled with the at least one processor.

Certain aspects provide an apparatus for wireless communications in a network by a user equipment (UE) . The apparatus generally includes means for receiving channel state information (CSI) reporting configuration information configuring the UE to perform CSI measurement and reporting, based on one or more CSI reference signals (CSI-RSs) , in one or more subbands (SBs) of a bandwidth part (BWP) of a system bandwidth, means for determining if a first SB of the one or more SBs includes a valid CSI-RS presence based on whether one or more threshold conditions, involving CSI-RS resources included in the first SB, are satisfied, and means for transmitting a CSI report corresponding to the first SB if it is determined that the first SB includes a valid CSI-RS presence.

Certain aspects provide a non-transitory computer-readable medium for wireless communications in a network by a user equipment (UE) . The non-transitory computer-readable medium generally includes instructions that, when executed by at least one processor, configure the at least one processor to receive channel state information (CSI) reporting configuration information configuring the UE to perform CSI measurement and reporting, based on one or more CSI reference signals (CSI-RSs) , in one or more subbands (SBs) of a bandwidth part (BWP) of a system bandwidth, determine if a first SB of the one or more SBs includes a valid CSI-RS presence based on whether one or more threshold conditions, involving CSI-RS resources included in the first SB, are satisfied, and transmit a CSI report corresponding to the first SB if it is determined that the first SB includes a valid CSI-RS presence.

Certain aspects provide a method for wireless communications in a network by a base station. The method generally includes determining channel state information (CSI) reporting configuration information configuring a user equipment to perform CSI measurement and reporting, based on one or more CSI reference signals (CSI-RSs) , in one or more subbands (SBs) of a bandwidth part (BWP) of a system bandwidth wherein the CSI reporting configuration information includes an SB size configuration, determining a CSI-RS resource configuration associated with the CSI reporting configuration information, transmitting the CSI reporting configuration information and the CSI-RS resource configuration to the UE, and receiving a CSI report corresponding to a first SB if the first SB includes a valid CSI presence based on whether one or more threshold conditions, involving CSI-RS resources included in the first SB, are satisfied.

Certain aspects provide an apparatus for wireless communications in a network by a base station. The apparatus generally includes at least one processor configured to determine channel state information (CSI) reporting configuration information configuring a user equipment to perform CSI measurement and reporting, based on one or more CSI reference signals (CSI-RSs) , in one or more subbands (SBs) of a bandwidth part (BWP) of a system bandwidth wherein the CSI reporting configuration information includes an SB size configuration, determine a CSI-RS resource configuration associated with the CSI reporting configuration information, transmit the CSI reporting configuration information and the CSI-RS resource configuration to the UE, and receive a CSI report corresponding to a first SB if the first SB includes a valid CSI presence based on whether one or more threshold conditions, involving CSI-RS resources included in the first SB, are satisfied. The apparatus also generally includes a memory coupled with the at least one processor.

Certain aspects provide an apparatus for wireless communications in a network by a base station. The apparatus generally includes means for determining channel state information (CSI) reporting configuration information configuring a user equipment to perform CSI measurement and reporting, based on one or more CSI reference signals (CSI-RSs) , in one or more subbands (SBs) of a bandwidth part (BWP) of a system bandwidth wherein the CSI reporting configuration information includes an SB size configuration, means for determining a CSI-RS resource configuration associated with the CSI reporting configuration information, means for transmitting the CSI reporting configuration information and the CSI-RS resource configuration to the UE, and means for receiving a CSI report corresponding to a first SB if the first SB includes a valid CSI presence based on whether one or more threshold conditions, involving CSI-RS resources included in the first SB, are satisfied.

Certain aspects provide a non-transitory computer-readable medium for wireless communications in a network by a user equipment (UE) . The non-transitory computer-readable medium generally includes instructions that, when executed by at least one processor, configure the at least one processor to determine channel state information (CSI) reporting configuration information configuring a user equipment to perform CSI measurement and reporting, based on one or more CSI reference signals (CSI-RSs) , in one or more subbands (SBs) of a bandwidth part (BWP) of a system bandwidth wherein the CSI reporting configuration information includes an SB size configuration, determine a CSI-RS resource configuration associated with the CSI reporting configuration information, transmit the CSI reporting configuration information and the CSI-RS resource configuration to the UE, and receive a CSI report corresponding to a first SB if the first SB includes a valid CSI presence based on whether one or more threshold conditions, involving CSI-RS resources included in the first SB, are satisfied.

To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the appended drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features of the present disclosure can be understood in detail, a more particular description, briefly summarized above, may be had by reference to aspects, some of which are illustrated in the drawings. It is to be noted, however, that the appended drawings illustrate only certain typical aspects of this disclosure and are therefore not to be considered limiting of its scope, for the description may admit to other equally effective aspects.

FIG. 1 is a block diagram conceptually illustrating an example telecommunications system, in accordance with certain aspects of the present disclosure.

FIG. 2 is a block diagram illustrating an example logical architecture of a distributed radio access network (RAN) , in accordance with certain aspects of the present disclosure.

FIG. 3 is a diagram illustrating an example physical architecture of a distributed RAN, in accordance with certain aspects of the present disclosure.

FIG. 4 is a block diagram conceptually illustrating a design of an example base station (BS) and user equipment (UE) , in accordance with certain aspects of the present disclosure.

FIG. 5 is a diagram showing examples for implementing a communication protocol stack, in accordance with certain aspects of the present disclosure.

FIG. 6 illustrates an example of a frame format for a new radio (NR) system, in accordance with certain aspects of the present disclosure.

FIG. 7 illustrates and example bandwidth portion and associated subbands of the bandwidth portion, in accordance with certain aspects of the present disclosure.

FIG. 8 illustrates and example channel state information reference signal resources in a bandwidth portion, in accordance with certain aspects of the present disclosure.

FIGs. 9A-9B illustrates example operations for wireless communications, in accordance with certain aspects of the present disclosure.

FIGs. 10A-10B illustrate example scenarios for determining whether a subband includes a valid channel state information reference signal resource presence, in accordance with certain aspects of the present disclosure.

FIGs. 11A-11C illustrate example scenarios for determining whether a subband includes a valid channel state information reference signal resource presence, in accordance with certain aspects of the present disclosure

FIGs. 12A-12C illustrate example scenarios for determining whether a subband includes a valid channel state information reference signal resource presence, in accordance with certain aspects of the present disclosure

FIG. 13 illustrates a communications device that may include various components configured to perform operations for the techniques disclosed herein in accordance with aspects of the present disclosure.

FIG. 14 illustrates a communications device that may include various components configured to perform operations for the techniques disclosed herein in accordance with aspects of the present disclosure.

To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one aspect may be beneficially utilized on other aspects without specific recitation.

DETAILED DESCRIPTION

Aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums for channel state information (CSI) reporting without full channel state information reference signal (CSI-RS) presence in a subband. For example, in some cases, techniques disclosed herein may involve determining whether the particular SB includes a valid CSI-RS resource presence and transmitting a CSI report if the particular SB includes a valid CSI-RS resource presence.

The following description provides examples, and is not limiting of the scope, applicability, or examples set forth in the claims. 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 steps 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 which 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 word “exemplary” is used herein to mean “serving as an example, instance, or illustration. ” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects.

The techniques described herein may be used for various wireless communication technologies, such as LTE, CDMA, TDMA, FDMA, OFDMA, SC-FDMA and other networks. The terms “network” and “system” are often used interchangeably. A CDMA network may implement a radio technology such as Universal Terrestrial Radio Access (UTRA) , cdma2000, etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. cdma2000 covers IS-2000, IS-95 and IS-856 standards. A TDMA network may implement a radio technology such as Global System for Mobile Communications (GSM) . An OFDMA network may implement a radio technology such as NR (e.g. 5G RA) , Evolved UTRA (E-UTRA) , Ultra Mobile Broadband (UMB) , IEEE 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Flash-OFDMA, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS) .

New Radio (NR) is an emerging wireless communications technology under development in conjunction with the 5G Technology Forum (5GTF) . 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described in documents from an organization named “3rd Generation Partnership Project” (3GPP) . cdma2000 and UMB are described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2) . The techniques described herein may be used for the wireless networks and radio technologies mentioned above as well as other wireless networks and radio technologies. For clarity, while aspects may be described herein using terminology commonly associated with 3G and/or 4G wireless technologies, aspects of the present disclosure can be applied in other generation-based communication systems, such as 5G and later, including NR technologies.

New radio (NR) access (e.g., 5G technology) may support various wireless communication services, such as enhanced mobile broadband (eMBB) targeting wide bandwidth (e.g., 80 MHz or beyond) , millimeter wave (mmW) targeting high carrier frequency (e.g., 25 GHz or beyond) , massive machine type communications MTC (mMTC) targeting non-backward compatible MTC techniques, and/or mission critical targeting ultra-reliable low-latency communications (URLLC) . These services may include latency and reliability requirements. These services may also have different transmission time intervals (TTI) to meet respective quality of service (QoS) requirements. In addition, these services may co-exist in the same subframe.

Example Wireless Communications System

FIG. 1 illustrates an example wireless communication network 100 in which aspects of the present disclosure may be performed. For example, the wireless communication network 100 may be a New Radio (NR) or 5G network.

As illustrated in FIG. 1, the wireless communication network 100 may include a number of base stations (BSs) 110 and other network entities. A BS may be a station that communicates with user equipments (UEs) . Each BS 110 may provide communication coverage for a particular geographic area. In 3GPP, the term “cell” can refer to a coverage area of a Node B (NB) and/or a Node B subsystem serving this coverage area, depending on the context in which the term is used. In NR systems, the term “cell” and next generation NodeB (gNB) , new radio base station (NR BS) , 5G NB, access point (AP) , or transmission reception point (TRP) may be interchangeable. In some examples, a cell may not necessarily be stationary, and the geographic area of the cell may move according to the location of a mobile BS. In some examples, the base stations may be interconnected to one another and/or to one or more other base stations or network nodes (not shown) in wireless communication network 100 through various types of backhaul interfaces, such as a direct physical connection, a wireless connection, a virtual network, or the like using any suitable transport network.

In general, any number of wireless networks may be deployed in a given geographic area. Each wireless network may support a particular radio access technology (RAT) and may operate on one or more frequencies. A RAT may also be referred to as a radio technology, an air interface, etc. A frequency may also be referred to as a carrier, a subcarrier, a frequency channel, a tone, a subband, etc. Each frequency may support a single RAT in a given geographic area in order to avoid interference between wireless networks of different RATs. In some cases, NR or 5G RAT networks may be deployed.

A base station (BS) may provide communication coverage for a macro cell, a pico cell, a femto cell, and/or other types of cells. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscription. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscription. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs having an association with the femto cell (e.g., UEs in a Closed Subscriber Group (CSG) , UEs for users in the home, etc. ) . A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS. In the example shown in FIG. 1, the

BSs

110a, 110b and 110c may be macro BSs for the

macro cells

102a, 102b and 102c, respectively. The BS 110x may be a pico BS for a pico cell 102x. The BSs 110y and 110z may be femto BSs for the

femto cells

102y and 102z, respectively. A BS may support one or multiple (e.g., three) cells.

Wireless communication network 100 may also include relay stations. A relay station is a station that receives a transmission of data and/or other information from an upstream station (e.g., a BS or a UE) and sends a transmission of the data and/or other information to a downstream station (e.g., a UE or a BS) . A relay station may also be a UE that relays transmissions for other UEs. In the example shown in FIG. 1, a relay station 110r may communicate with the BS 110a and a UE 120r in order to facilitate communication between the BS 110a and the UE 120r. A relay station may also be referred to as a relay BS, a relay, etc.

Wireless communication network 100 may be a heterogeneous network that includes BSs of different types, e.g., macro BS, pico BS, femto BS, relays, etc. These different types of BSs may have different transmit power levels, different coverage areas, and different impact on interference in the wireless communication network 100. For example, macro BS may have a high transmit power level (e.g., 20 Watts) whereas pico BS, femto BS, and relays may have a lower transmit power level (e.g., 1 Watt) .

Wireless communication network 100 may support synchronous or asynchronous operation. For synchronous operation, the BSs may have similar frame timing, and transmissions from different BSs may be approximately aligned in time. For asynchronous operation, the BSs may have different frame timing, and transmissions from different BSs may not be aligned in time. The techniques described herein may be used for both synchronous and asynchronous operation.

A network controller 130 may couple to a set of BSs and provide coordination and control for these BSs. The network controller 130 may communicate with the BSs 110 via a backhaul. The BSs 110 may also communicate with one another (e.g., directly or indirectly) via wireless or wireline backhaul.

The UEs 120 (e.g., 120x, 120y, etc. ) may be dispersed throughout the wireless communication network 100, and each UE may be stationary or mobile. A UE may also be referred to as a mobile station, a terminal, an access terminal, a subscriber unit, a station, a Customer Premises Equipment (CPE) , a cellular phone, a smart phone, a personal digital assistant (PDA) , a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet computer, a camera, a gaming device, a netbook, a smartbook, an ultrabook, an appliance, a medical device or medical equipment, a biometric sensor/device, a wearable device such as a smart watch, smart clothing, smart glasses, a smart wrist band, smart jewelry (e.g., a smart ring, a smart bracelet, etc. ) , an entertainment device (e.g., a music device, a video device, a satellite radio, etc. ) , a vehicular component or sensor, a smart meter/sensor, industrial manufacturing equipment, a global positioning system device, or any other suitable device that is configured to communicate via a wireless or wired medium. Some UEs may be considered machine-type communication (MTC) devices or evolved MTC (eMTC) devices. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, etc., that may communicate with a BS, another device (e.g., remote device) , or some other entity. A wireless node may provide, for example, connectivity for or to a network (e.g., a wide area network such as Internet or a cellular network) via a wired or wireless communication link. Some UEs may be considered Internet-of-Things (IoT) devices, which may be narrowband IoT (NB-IoT) devices.

Certain wireless networks (e.g., LTE) utilize orthogonal frequency division multiplexing (OFDM) on the downlink and single-carrier frequency division multiplexing (SC-FDM) on the uplink. OFDM and SC-FDM partition the system bandwidth into multiple (K) orthogonal subcarriers, which are also commonly referred to as tones, bins, etc. Each subcarrier may be modulated with data. In general, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDM. The spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may be dependent on the system bandwidth. For example, the spacing of the subcarriers may be 15 kHz and the minimum resource allocation (called a “resource block” (RB) ) may be 12 subcarriers (or 180 kHz) . Consequently, the nominal Fast Fourier Transfer (FFT) size may be equal to 128, 256, 512, 1024 or 2048 for system bandwidth of 1.25, 2.5, 5, 10, or 20 megahertz (MHz) , respectively. The system bandwidth may also be partitioned into subbands. For example, a subband may cover 1.08 MHz (i.e., 6 resource blocks) , and there may be 1, 2, 4, 8, or 16 subbands for system bandwidth of 1.25, 2.5, 5, 10 or 20 MHz, respectively.

While aspects of the examples described herein may be associated with LTE technologies, aspects of the present disclosure may be applicable with other wireless communications systems, such as NR. NR may utilize OFDM with a CP on the uplink and downlink and include support for half-duplex operation using TDD. Beamforming may be supported and beam direction may be dynamically configured. MIMO transmissions with precoding may also be supported. MIMO configurations in the DL may support up to 8 transmit antennas with multi-layer DL transmissions up to 8 streams and up to 2 streams per UE. Multi-layer transmissions with up to 2 streams per UE may be supported. Aggregation of multiple cells may be supported with up to 8 serving cells.

In some examples, access to the air interface may be scheduled, wherein a scheduling entity (e.g., a base station) allocates resources for communication among some or all devices and equipment within its service area or cell. The scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communication, subordinate entities utilize resources allocated by the scheduling entity. Base stations are not the only entities that may function as a scheduling entity. In some examples, a UE may function as a scheduling entity and may schedule resources for one or more subordinate entities (e.g., one or more other UEs) , and the other UEs may utilize the resources scheduled by the UE for wireless communication. In some examples, a UE may function as a scheduling entity in a peer-to-peer (P2P) network, and/or in a mesh network. In a mesh network example, UEs may communicate directly with one another in addition to communicating with a scheduling entity.

In FIG. 1, a solid line with double arrows indicates desired transmissions between a UE and a serving BS, which is a BS designated to serve the UE on the downlink and/or uplink. A finely dashed line with double arrows indicates interfering transmissions between a UE and a BS.

FIG. 2 illustrates an example logical architecture of a distributed Radio Access Network (RAN) 200, which may be implemented in the wireless communication network 100 illustrated in FIG. 1. A 5G access node 206 may include an access node controller (ANC) 202. ANC 202 may be a central unit (CU) of the distributed RAN 200. The backhaul interface to the Next Generation Core Network (NG-CN) 204 may terminate at ANC 202. The backhaul interface to neighboring next generation access Nodes (NG-ANs) 210 may terminate at ANC 202. ANC 202 may include one or more transmission reception points (TRPs) 208 (e.g., cells, BSs, gNBs, etc. ) .

The TRPs 208 may be a distributed unit (DU) . TRPs 208 may be connected to a single ANC (e.g., ANC 202) or more than one ANC (not illustrated) . For example, for RAN sharing, radio as a service (RaaS) , and service specific AND deployments, TRPs 208 may be connected to more than one ANC. TRPs 208 may each include one or more antenna ports. TRPs 208 may be configured to individually (e.g., dynamic selection) or jointly (e.g., joint transmission) serve traffic to a UE.

The logical architecture of distributed RAN 200 may support fronthauling solutions across different deployment types. For example, the logical architecture may be based on transmit network capabilities (e.g., bandwidth, latency, and/or jitter) .

The logical architecture of distributed RAN 200 may share features and/or components with LTE. For example, next generation access node (NG-AN) 210 may support dual connectivity with NR and may share a common fronthaul for LTE and NR.

The logical architecture of distributed RAN 200 may enable cooperation between and among TRPs 208, for example, within a TRP and/or across TRPs via ANC 202. An inter-TRP interface may not be used.

Logical functions may be dynamically distributed in the logical architecture of distributed RAN 200. As will be described in more detail with reference to FIG. 5, the Radio Resource Control (RRC) layer, Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer, Medium Access Control (MAC) layer, and a Physical (PHY) layers may be adaptably placed at the DU (e.g., TRP 208) or CU (e.g., ANC 202) .

FIG. 3 illustrates an example physical architecture of a distributed Radio Access Network (RAN) 300, according to aspects of the present disclosure. A centralized core network unit (C-CU) 302 may host core network functions. C-CU 302 may be centrally deployed. C-CU 302 functionality may be offloaded (e.g., to advanced wireless services (AWS) ) , in an effort to handle peak capacity.

A centralized RAN unit (C-RU) 304 may host one or more ANC functions. Optionally, the C-RU 304 may host core network functions locally. The C-RU 304 may have distributed deployment. The C-RU 304 may be close to the network edge.

A DU 306 may host one or more TRPs (Edge Node (EN) , an Edge Unit (EU) , a Radio Head (RH) , a Smart Radio Head (SRH) , or the like) . The DU may be located at edges of the network with radio frequency (RF) functionality.

FIG. 4 illustrates example components of BS 110 and UE 120 (as depicted in FIG. 1) , which may be used to implement aspects of the present disclosure. For example, antennas 452,

processors

466, 458, 464, and/or controller/processor 480 of the UE 120 and/or antennas 434,

processors

420, 430, 438, and/or controller/processor 440 of the BS 110 may be used to perform the various techniques and methods described herein.

At the BS 110, a transmit processor 420 may receive data from a data source 412 and control information from a controller/processor 440. The control information may be for the physical broadcast channel (PBCH) , physical control format indicator channel (PCFICH) , physical hybrid ARQ indicator channel (PHICH) , physical downlink control channel (PDCCH) , group common PDCCH (GC PDCCH) , etc. The data may be for the physical downlink shared channel (PDSCH) , etc. The processor 420 may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. The processor 420 may also generate reference symbols, e.g., for the primary synchronization signal (PSS) , secondary synchronization signal (SSS) , and cell-specific reference signal (CRS) . A transmit (TX) multiple-input multiple-output (MIMO) processor 430 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) of the modulators/demodulators 432a through 432t. Each modulator of the modulators/demodulators 432a through 432t may process a respective output symbol stream (e.g., for OFDM, etc. ) 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 modulators of the modulators/demodulators 432a through 432t may be transmitted via the antennas 434a through 434t, respectively.

At the UE 120, the antennas 452a through 452r may receive the downlink signals from the base station 110 and may provide received signals to the demodulators (DEMODs) in modulators/demodulators 454a through 454r, respectively. Each demodulator of the modulators/demodulators 454a through 454r 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 (e.g., for OFDM, etc. ) to obtain received symbols. A MIMO detector 456 may obtain received symbols from all the demodulators of the modulators/demodulators 454a through 454r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor 458 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for the UE 120 to a data sink 460, and provide decoded control information to a controller/processor 480.

On the uplink, at UE 120, a transmit processor 464 may receive and process data (e.g., for the physical uplink shared channel (PUSCH) ) from a data source 462 and control information (e.g., for the physical uplink control channel (PUCCH) from the controller/processor 480. The transmit processor 464 may also generate reference symbols for a reference signal (e.g., for the sounding reference signal (SRS) ) . The symbols from the transmit processor 464 may be precoded by a TX MIMO processor 466 if applicable, further processed by the demodulators of the modulators/demodulators 454a through 454r (e.g., for SC-FDM, etc. ) , and transmitted to the base station 110. At the BS 110, the uplink signals from the UE 120 may be received by the antennas 434, processed by the modulators 432, detected by a MIMO detector 436 if applicable, and further processed by a receive processor 438 to obtain decoded data and control information sent by the UE 120. The receive processor 438 may provide the decoded data to a data sink 439 and the decoded control information to the controller/processor 440.

The controllers/

processors

440 and 480 may direct the operation at the base station 110 and the UE 120, respectively. The processor 440 and/or other processors and modules at the BS 110 may perform or direct the execution of processes for the techniques described herein. The

memories

442 and 482 may store data and program codes for BS 110 and UE 120, respectively. A scheduler 444 may schedule UEs for data transmission on the downlink and/or uplink.

FIG. 5 illustrates a diagram 500 showing examples for implementing a communications protocol stack, according to aspects of the present disclosure. The illustrated communications protocol stacks may be implemented by devices operating in a wireless communication system, such as a 5G system (e.g., a system that supports uplink-based mobility) . Diagram 500 illustrates a communications protocol stack including a Radio Resource Control (RRC) layer 510, a Packet Data Convergence Protocol (PDCP) layer 515, a Radio Link Control (RLC) layer 520, a Medium Access Control (MAC) layer 525, and a Physical (PHY) layer 530. In various examples, the layers of a protocol stack may be implemented as separate modules of software, portions of a processor or ASIC, portions of non-collocated devices connected by a communications link, or various combinations thereof. Collocated and non-collocated implementations may be used, for example, in a protocol stack for a network access device (e.g., ANs, CUs, and/or DUs) or a UE.

A first option 505-ashows a split implementation of a protocol stack, in which implementation of the protocol stack is split between a centralized network access device (e.g., an ANC 202 in FIG. 2) and distributed network access device (e.g., the DU of the TRP 208 in FIG. 2) . In the first option 505-a, an RRC layer 510 and a PDCP layer 515 may be implemented by the central unit, and an RLC layer 520, a MAC layer 525, and a PHY layer 530 may be implemented by the DU. In various examples the CU and the DU may be collocated or non-collocated. The first option 505-a may be useful in a macro cell, micro cell, or pico cell deployment.

A second option 505-b shows a unified implementation of a protocol stack, in which the protocol stack is implemented in a single network access device. In the second option, RRC layer 510, PDCP layer 515, RLC layer 520, MAC layer 525, and PHY layer 530 may each be implemented by the AN. The second option 505-b may be useful in, for example, a femto cell deployment.

Regardless of whether a network access device implements part or all of a protocol stack, a UE may implement an entire protocol stack as shown in 505-c (e.g., the RRC layer 510, the PDCP layer 515, the RLC layer 520, the MAC layer 525, and the PHY layer 530) .

In LTE, the basic transmission time interval (TTI) or packet duration is the 1 ms subframe. In NR, a subframe is still 1 ms, but the basic TTI is referred to as a slot. A subframe contains a variable number of slots (e.g., 1, 2, 4, 8, 16, …slots) depending on the subcarrier spacing. The NR RB is 12 consecutive frequency subcarriers. NR may support a base subcarrier spacing of 15 KHz and other subcarrier spacing may be defined with respect to the base subcarrier spacing, for example, 30 kHz, 60 kHz, 120 kHz, 240 kHz, etc. The symbol and slot lengths scale with the subcarrier spacing. The CP length also depends on the subcarrier spacing.

FIG. 6 is a diagram showing an example of a frame format 600 for NR. The transmission timeline for each of the downlink and uplink may be partitioned into units of radio frames. Each radio frame may have a predetermined duration (e.g., 10 ms) and may be partitioned into 10 subframes, each of 1 ms, with indices of 0 through 9. Each subframe may include a variable number of slots depending on the subcarrier spacing. Each slot may include a variable number of symbol periods (e.g., 7 or 14 symbols) depending on the subcarrier spacing. The symbol periods in each slot may be assigned indices. A mini-slot, which may be referred to as a sub-slot structure, refers to a transmit time interval having a duration less than a slot (e.g., 2, 3, or 4 symbols) .

Each symbol in a slot may indicate a link direction (e.g., DL, UL, or flexible) for data transmission and the link direction for each subframe may be dynamically switched. The link directions may be based on the slot format. Each slot may include DL/UL data as well as DL/UL control information.

In NR, a synchronization signal (SS) block is transmitted. The SS block includes a PSS, a SSS, and a two symbol PBCH. The SS block can be transmitted in a fixed slot location, such as the symbols 0-3 as shown in FIG. 6. The PSS and SSS may be used by UEs for cell search and acquisition. The PSS may provide half-frame timing, the SS may provide the CP length and frame timing. The PSS and SSS may provide the cell identity. The PBCH carries some basic system information, such as downlink system bandwidth, timing information within radio frame, SS burst set periodicity, system frame number, etc. The SS blocks may be organized into SS bursts to support beam sweeping. Further system information such as, remaining minimum system information (RMSI) , system information blocks (SIBs) , other system information (OSI) can be transmitted on a physical downlink shared channel (PDSCH) in certain subframes. The SS block may be transmitted up to sixty-four times, for example, with up to sixty-four different beam directions for mmW. The up to sixty-four transmissions of the SS block are referred to as the SS burst set.

In some circumstances, two or more subordinate entities (e.g., UEs) may communicate with each other using sidelink signals. Real-world applications of such sidelink communications may include public safety, proximity services, UE-to-network relaying, vehicle-to-vehicle (V2V) communications, Internet of Everything (IoE) communications, IoT communications, mission-critical mesh, and/or various other suitable applications. Generally, a sidelink signal may refer to a signal communicated from one subordinate entity (e.g., UE1) to another subordinate entity (e.g., UE2) without relaying that communication through the scheduling entity (e.g., UE or BS) , even though the scheduling entity may be utilized for scheduling and/or control purposes. In some examples, the sidelink signals may be communicated using a licensed spectrum (unlike wireless local area networks, which typically use an unlicensed spectrum) .

A UE may operate in various radio resource configurations, including a configuration associated with transmitting pilots using a dedicated set of resources (e.g., a radio resource control (RRC) dedicated state, etc. ) or a configuration associated with transmitting pilots using a common set of resources (e.g., an RRC common state, etc. ) . When operating in the RRC dedicated state, the UE may select a dedicated set of resources for transmitting a pilot signal to a network. When operating in the RRC common state, the UE may select a common set of resources for transmitting a pilot signal to the network. In either case, a pilot signal transmitted by the UE may be received by one or more network access devices, such as an AN, or a DU, or portions thereof. Each receiving network access device may be configured to receive and measure pilot signals transmitted on the common set of resources, and also receive and measure pilot signals transmitted on dedicated sets of resources allocated to the UEs for which the network access device is a member of a monitoring set of network access devices for the UE. One or more of the receiving network access devices, or a CU to which receiving network access device (s) transmit the measurements of the pilot signals, may use the measurements to identify serving cells for the UEs, or to initiate a change of serving cell for one or more of the UEs.

Example CSI Reporting Without Full CSI-RS Presence

In 5G new radio (NR) , channel state information (CSI) reporting may be configured to be performed on a bandwidth portion (BWP) of a larger system bandwidth associated with a non-zero power (NZP) channel state information reference signal (CSI- RS) resource for channel measurement, for example, as illustrated in FIG. 7 and Table 1, below. For example, as illustrated in Table 1, the BWP may range from a size of 24 RBs to 275 RBs. Additionally, as illustrated in Table 1, each BWP size range may correspond to two candidate SB sizes (e.g., 4, 8, 16, or 32) . According to aspects, the BWP may start from any RB of the entire system bandwidth and end at any RB of the entire system bandwidth. The subband size to use for a given BWP size may be configured by a base station (BS) , for example, using one bit in configuration information. For example, for a BWP size of 72 RBs, the SB can be 4 or 8. If the BS configures an SB size as 4 RBs, then the entire system bandwidth may be cut into grids of 4RBs, for example, as illustrated at 702 in FIG. 7.

BWP Size (RBs)	Subband Size (RBs)
< 24	N/A
24-72	4, 8
73-144	8, 16
145-275	16, 32

Table 1: BWP size and corresponding Subband sizes

In some cases, since the BWP may start from any RB in the system bandwidth, a starting RB of a BWP may not be an integer multiple of a SB size, such as the case of an edge SB. For example, edge SBs may have a smaller number of RBs than a SB size configured by the network. For example, as illustrated in FIG. 7, assuming a BWP size of 72 RBs, starting from the RB 3 to RB 74 in the system bandwidth, and a SB size equal to 4 RBs, a first SB only has one RB, (e.g., the RB 3) , while each of the 2nd to the 18th SBs have 4RBs and while the last SB (i.e., 19th SB) has 3 RBs (e.g., from RB 72 to RB 74) . Thus, the first and last SBs (e.g., SB3 and SB19) may be considered edge SBs with a number of RBs less than the configured SB size.

In some cases, NZP CSI measurement resource (CMR) , the NZP interference measurement resource (IMR) , or CSI IMR may have a different frequency occupation than the configured CSI reporting BWP. For example, as illustrated in FIG. 8A, CSI-RS resources 802A may only span a subset of the RBs included in the BWP (e.g., SB3-SB18) and, in some cases, may not span an entire SB. Thus, in this sense, some SBs include full CSI-RS presence, some SBs include a partial CSI-RS presence, and some SBs include no CSI-RS presence. For example, as illustrated, the CSI-RS resources span only a portion of SB3 (e.g., two of the four RBs of SB3) while also spanning all of the RBs included in SB4. Thus, SB3 may be known as having a partial CSI-RS resource presence while SB4 may be known as having a full CSI-RS resource presence. Further, as illustrated, SB2 includes no CSI-RS presence (e.g., CSI-RS resources 802A do not span SB2) .

According to aspects, in FIG. 8A, each RB may include CSI-RS resources, so a configured CSI-RS resource density may be equal to 1. Note that when density is greater than 1 (e.g., 3) , it means that there are 3 CSI-RS resources in one RB, which may be treated similar to density 1 since at least every RB has CSI-RS resources. According to aspects, as illustrated in FIG. 8B, every two RBs may include one CSI-RS resource, so the configured density may be 0.5. According to aspects, when the configured density is 0.5, even or odd RBs may be configured to include the CSI-RS resources.

According to aspects, as illustrated in FIG. 7, since a BWP may include 19 SBs the BS can configure the UE to report CSI for a subset of these 19 SBs. For instance, the BS may instruct the UE to report CSI from SB2 to SB18, excluding reporting CSI on edge SBs as shown in FIG. 7 (e.g., SB1 and SB19) . In other cases, the BS may also request the UE to report CSI on edge SBs. Thus, on which SB the UE should report CSI may be dependent on configuration information received by the BS.

Currently, certain standards define how a UE should handle CSI-RS reporting depending on a presence of CSI-RS resources included in SBs. For example, currently, a UE may be configured to ignore CSI reporting for SBs (e.g., not report CSI) that do not include any CSI-RS resources (e.g., SB2 in FIG. 8A) and to report CSI in SBs that include a full CSI-RS presence (e.g., SBs 4-18 in FIG. 8A) . However, it remains open how to treat CSI reporting in SBs with partial CSI-RS resource presence (e.g., SB3 in FIG. 8A) , as described above.

Thus, aspects of the present disclosure propose techniques for handling CSI reporting when there is only a partial presence of CSI-RS resources in a particular SB. In some cases, techniques may involve determining whether the particular SB includes a valid CSI-RS resource presence and transmitting a CSI report if the particular SB includes a valid CSI-RS resource presence.

FIG. 9A illustrates example operations 900A for wireless communications in a network by a user equipment, for example, for channel state information (CSI) reporting without full channel state information reference signal (CSI-RS) presence in a subband.

According to aspects, the UE may include one or more components as illustrated in FIG. 4 which may be configured to perform the operations described herein. For example, the antenna 452, demodulator/modulator 454, controller/processor 480, and/or memory 482 as illustrated in FIG. 4 may perform the operations described herein.

Operations 900A begin at 902A by receiving channel state information (CSI) reporting configuration information configuring the UE to perform CSI measurement and reporting, based on one or more CSI reference signals (CSI-RSs) , in one or more subbands (SBs) of a bandwidth part (BWP) of a system bandwidth. In some cases, the CSI reporting configuration includes an SB size configuration. Additionally, while not illustrated, the UE may receive a CSI-RS resource configuration associated with the CSI reporting configuration.

At 904A, the UE determines if a first SB of the one or more SBs includes a valid CSI-RS presence based on whether one or more threshold conditions, involving CSI-RS resources included in the first SB, are satisfied; and

At 906A, the UE transmits a CSI report corresponding to the first SB if it is determined that the first SB includes a valid CSI-RS presence.

FIG. 9B illustrates example operations 900B for wireless communications in a network by a user equipment, for example, for channel state information (CSI) reporting without full channel state information reference signal (CSI-RS) presence in a subband.

The base station may include one or more components as illustrated in FIG. 4 which may be configured to perform the operations described herein. For example, the antenna 434, modulator/demodulator 432, transmit processor 420, controller/processor 440, and/or memory 442 of the base station 110, as illustrated in FIG. 4, may perform the operations described herein.

Operations 900B begin at 902B by determining channel state information (CSI) reporting configuration information configuring a user equipment to perform CSI measurement and reporting, based on one or more CSI reference signals (CSI-RSs) , in one or more subbands (SBs) of a bandwidth part (BWP) of a system bandwidth, wherein the CSI reporting configuration information includes an SB size configuration.

At 904B, the BS determines a CSI-RS resource configuration associated with the CSI reporting configuration information.

At 906B, the base station transmits the CSI reporting configuration information and the CSI-RS resource configuration to the UE.

At 908B, the base station receives a CSI report corresponding to a first SB if the first SB includes a valid CSI presence based on whether one or more threshold conditions, involving CSI-RS resources included in the first SB, are satisfied.

As noted above, aspects of the present disclosure provide for techniques channel state information (CSI) reporting without full channel state information reference signal (CSI-RS) presence (e.g., partial presence) in a subband. In some cases, a first subband may be deemed to have only a partial CSI-RS presence when an effective CSI-RS density of the first SB is less than a configured CSI-RS density (e.g., as indicated in the CSI reporting configuration information received by the UE) for the first SB.

Additionally or alternatively, in some cases, the first subband may be deemed to have only a partial CSI-RS presence when a number of RBs including CSI-RS resources in the first SB is smaller than a number of RBs with CSI-RS resources of a SB with full CSI-RS resource presence. According to aspects, the number of RBs with CSI-RS with full CSI-RS presence may be equal to a number of RBs in the first SB multiplied by a configured CSI-RS density for the first SB.

Additionally or alternatively, in some cases, the first subband may be deemed to have only a partial CSI-RS presence when a gap between a starting RB of CSI-RS resources in the first SB and a starting of the first SB is greater than a gap in a second SB with full CSI-RS presence. Likewise, in some cases, the first subband may be deemed to have only a partial CSI-RS presence when a gap between an ending RB of CSI-RS resources in the first SB and an ending of the first SB is greater than a gap in a second SB with full CSI-RS presence

According to aspects, a UE’s behavior regarding CSI reporting when there is only a partial presence of CSI-RS resources present in a subband may be based on whether one or more threshold conditions are satisfied. For example, the UE may determine if a first SB of one or more SBs of a BWP includes a valid CSI-RS presence based on whether one or more threshold conditions, involving CSI-RS resources included in the first SB, are satisfied. According to aspects, if the UE determines that the first SB includes a valid CSI-RS presence, the UE may transmit a CSI report corresponding to the first SB. If, however, the UE determines that the first SB does not include a valid CSI-RS presence, the UE may take some other action, such as not transmitting a CSI report corresponding to the first SB or transmitting a “garbage” CSI report corresponding to the first SB that includes information that is meaningless to the network.

According to aspects, in some cases, the threshold condition may comprise an effective density of CSI-RS resources in the first SB being greater than or equal to a threshold effective density. According to aspects, the effective density (e.g., d _eff) of CSI-RS resources may be equal to the ratio between a number of resource blocks of the first SB including CSI-RS resources (e.g., N) and a total number of configured RBs included in the first SB (e.g., M) , or d _eff = N/M. According to aspects, the threshold effective density may comprise a first threshold value (e.g., . 6) for a first configured CSI-RS density (e.g., 1) and a second threshold value (e.g., . 3) for a second configured CSI-RS density (e.g., . 5) . In some cases, the first threshold value and the second threshold value may be configured by the network. In some cases, the first threshold value and/or the second threshold value may be fixed (e.g., in a standards document) and may comprise a nominal/original CSI-RS density configured by the network.

FIG. 10A illustrates examples of determining a valid CSI-RS resource presence (e.g., for non-edge SBs) based on an SB threshold effective density, for example, assuming a network-configured SB size of 8RBs. For example, as illustrated at 1002A, the UE may determine that the CSI-RS presence in a given SB of 8 RBs with a configured CSI-RS resource density of 1 is valid since the effective density (. 75) is greater than the configured effective threshold density (e.g., . 6) . More specifically, the UE may determine that CSI-RS resources are included in 6 RBs of the SB and, based on the 8 total RBs of the SB, determine that the effective density of the SB is . 75. Thus, the UE may then determine that the SB includes a valid CSI-RS presence since the effective density of the CSI-RS resources in the SB (e.g., . 75) is greater than the effective threshold density (e.g., . 6) . The UE may perform similar operations to determine a valid CSI-RS resource presence in SBs that include a configured CSI-RS resource density of. 5, for example, as illustrated at 1004A.

In other cases, such as illustrated at 1006A, the UE may determine that the CSI-RS presence in a given SB of 8 RBs with a configured CSI-RS resource density of 1 is not valid since the effective density (. 375) is less than the configured effective threshold density (e.g., . 6) . More specifically, the UE may determine that CSI-RS resources are included in 3 RBs of the SB and, based on the 8 total RBs of the SB, determine that the effective density of the SB is . 375. Thus, the UE may then determine that the SB does not include a valid CSI-RS presence since the effective density of the CSI-RS resources in the SB (e.g., . 375) is less than the effective threshold density (e.g., . 6) . The UE may perform similar operations to determine an invalid CSI-RS resource presence in SBs that include a configured CSI-RS resource density of. 5, for example, as illustrated at 1008A.

Additionally, in some cases, determination of whether the first SB includes a valid CS-RS resource presence may also depend on an RB size of the first SB and a threshold size (e.g., especially for edge SBs as described above) . For example, even if the effective density for the first SB is greater than or equal to the threshold effective density, the UE may determine that the first SB does not include a valid CSI-RS resource presence if the RB size of the first SB is not greater than or equal to the threshold size. For example, assuming the effective density of the first threshold meets or exceeds the threshold effective density, if the RB size of the first SB is equal to 3RBs and the threshold size is equal to 5RBs, the UE may determine that the first SB does not include a valid CSI-RS resource presence.

FIG. 10B illustrates examples of determining a valid CSI-RS resource presence (e.g., for edge SBs) based on an SB threshold effective density and a threshold RB size of an SB, for example, assuming a network-configured SB size of 8RBs. For example, as illustrated in FIG. 10B at 1002B, the UE may determine that the CSI-RS presence in a given SB of 5 RBs with a configured CSI-RS resource density of 1 is valid since the number of RBs in the SB (e.g., 5 RBs) is equal to the configured threshold size (e.g., 5 RBs) and since the effective CSI-RS resource density (e.g., . 6) is equal to the configured threshold density (e.g., . 6) . The UE may perform similar operations to determine a valid CSI-RS resource presence in SBs that include a configured CSI-RS resource density of. 5, for example, as illustrated at 1004B.

In other cases, such as illustrated at 1006B, the UE may determine that the CSI-RS presence in a given SB of 3 RBs with a configured CSI-RS resource density of 1 is not valid since the number of RBs in the SB (e.g., 3 RBs) is equal to the configured threshold size (e.g., 5 RBs) . The UE may perform similar operations to determine an invalid CSI-RS resource presence in SBs that include a configured CSI-RS resource density of. 5, for example, as illustrated at 1008B.

According to aspects, in some cases, the threshold condition may comprise a number RBs without CSI-RS resources in the first SB being less than or equal to a first RB threshold or a number of RBs with CSI-RS resources in the first SB being greater than or equal to a second SB threshold.

For example, according to aspects, the first RB threshold (and/or the second RB threshold) may comprise a first threshold value (e.g., 3RBs for a configured SB size of 8RBs) for a first configured CSI-RS density (e.g., 1) and a second threshold value (e.g., 5RBs for a configured SB size of 8RBs) for a second configured CSI-RS density (e.g., . 5) . Thus, for example, as long as the number of RBs in the first SB without CSI-RS resources is below the first threshold, the UE may determine that the first SB includes a valid CSI-RS resource presence. According to aspects, in some cases, the first threshold value and the second threshold value may be configured by the network or fixed in a standards document.

Further, it should be noted that the first threshold value and the second threshold value may be dependent upon the configured SB size (e.g., in RBs) . For example, the first and second threshold values may be lower for a configured SB size of 4RBs as compared to a configured SB size of 8RBs. For example, the first and second threshold values for a configured SB size of 8RBs may be 3RBs and 5RBs, respectively, while the first and second threshold values for a configured SB size of 4RBs may be 1RB and 2RBs, respectively.

FIG. 11A illustrates various examples of determining a valid CSI-RS resource presence (e.g., for non-edge SBs) based on a number RBs without CSI-RS resources in the first SB being less than or equal to a first RB threshold, for example, assuming a network-configured SB size of 8RBs. A similar process may be used to determine whether the first SB includes a valid CSI-RS resource presence based on a number of RBs with CSI-RS resources in the first SB being greater than or equal to a second SB threshold.

For example, as illustrated at 1102A, the UE may determine that the CSI-RS presence in a given SB of 8 RBs with a configured CSI-RS resource density of 1 is valid since the number of RBs in the SB without CSI-RS resources (e.g., 2 RBs) is less than the configured first threshold size (e.g., 3 RBs) . The UE may perform similar operations to determine an invalid CSI-RS resource presence in SBs that include a configured CSI-RS resource density of. 5, for example, as illustrated at 1104A.

In other cases, such as illustrated at 1106A, the UE may determine that the CSI-RS presence in a given SB of 3 RBs with a configured CSI-RS resource density of 1 is not valid since the number of RBs in the SB without CSI-RS resources (e.g., 5 RBs) is greater than the configured first threshold size (e.g., 3 RBs) . The UE may perform similar operations to determine an invalid CSI-RS resource presence in SBs that include a configured CSI-RS resource density of. 5, for example, as illustrated at 1108A.

Additionally, FIG. 11B illustrates various examples of determining a valid CSI-RS resource presence (e.g., for non-edge SBs) based on a number RBs without CSI-RS resources in the first SB being less than or equal to a first RB threshold, for example, assuming a network-configured SB size of 4RBs. As noted above, a similar process may be used to determine whether the first SB includes a valid CSI-RS resource presence based on a number of RBs with CSI-RS resources in the first SB being greater than or equal to a second SB threshold. According to aspects, operations performed by the UE for determining a valid CSI-RS resource corresponding to the network-configured SB size of 4RBs in FIG. 11B may be similar to the operations performed by the UE for determining a valid CSI-RS resource corresponding to the network-configured SB size of 8RBs in FIG. 11A.

Additionally, in some cases, the determination of whether the first SB includes a valid CS-RS resource presence may also depend on an RB size of the first SB and a threshold size (e.g., especially for edge SBs as described above) . For example, even if the number RBs without CSI-RS resources in the first SB is less than or equal to a first RB threshold or a number of RBs with CSI-RS resources in the first SB is greater than or equal to a second SB threshold, the UE may determine that the first SB does not include a valid CSI-RS resource presence if the RB size of the first SB is not greater than or equal to the threshold size. For example, assuming the number RBs without CSI-RS resources in the first SB is less than or equal to the first RB threshold or a number of RBs with CSI-RS resources in the first SB is greater than or equal to the second SB threshold, if the RB size of the first SB is equal to 3RBs and the threshold size is equal to 5RBs, the UE may determine that the first SB does not include a valid CSI-RS resource presence.

FIG. 11C illustrates examples of determining a valid CSI-RS resource presence (e.g., for edge SBs) based on a number RBs without CSI-RS resources in the first SB being less than or equal to a first RB threshold, for example, assuming a network-configured SB size of 8RBs. A similar process may be used when the network-configured SB size is 4RBs.

For example, as illustrated at 1102C, the UE may determine that the CSI-RS presence in a given edge SB of 5 RBs with a configured CSI-RS resource density of 1 is valid since the number of RBs in the edge SB without CSI-RS resources (e.g., 2 RBs) is less than the configured first threshold size (e.g., 3 RBs) and since the number of RBs in the edge SB (e.g., 5) is equal to the threshold RB size (e.g., 5) . The UE may perform similar operations to determine an invalid CSI-RS resource presence in SBs that include a configured CSI-RS resource density of. 5, for example, as illustrated at 1104C.

In other cases, such as illustrated at 1106C, the UE may determine that the CSI-RS presence in a given edge SB of 3 RBs with a configured CSI-RS resource density of 1 is not valid since, while the number of RBs in the edge SB without CSI-RS resources (e.g., 0 RBs) is less than the configured first threshold size (e.g., 3 RBs) , the number of RBs in the edge SB (e.g., 3) is less than the threshold RB size (e.g., 5) . The UE may perform similar operations to determine an invalid CSI-RS resource presence in SBs that include a configured CSI-RS resource density of. 5, for example, as illustrated at 1108C.

According to aspects, in some cases, as noted above, the threshold condition may comprise a gap between a starting RB of a CSI-RS resource in the first SB and a starting RB of the first SB being less than or equal to a first threshold RB gap or a gap between an ending RB of a CSI-RS resource in the first SB and an ending RB of the first SB being less than or equal to the first threshold RB gap.

According to aspects, if the UE determines that the number of gap RBs between the starting RB of the CSI-RS resource in the first SB and the starting RB of the first SB is less than the threshold RB gap, the UE may then determine that the first SB includes a valid CSI-RS resource presence. Similarly, if the UE determines that the number of gap RBs between the ending RB of the CSI-RS resource in the first SB and the ending RB of the first SB is less than the threshold RB gap, then the UE may determine that the first SB includes a valid CSI-RS resource presence. According to aspects, in some cases, the first threshold RB gap may be configured by the network or fixed in a standards document.

Further, it should be noted that the first threshold RB gap may be dependent upon the configured SB size (e.g., in RBs) . For example, the threshold RB gaps may be lower for a configured SB size of 4RBs as compared to a configured SB size of 8RBs. For example, the threshold RB gaps for a configured SB size of 8RBs may be 3RBs, while the threshold RB gaps for a configured SB size of 4RBs may be 1RB.

FIG. 12A illustrates various examples of determining a valid CSI-RS resource presence (e.g., for non-edge SBs) based on a gap between a starting RB of a CSI-RS resource in the first SB and a starting RB of the first SB being less than or equal to a first threshold RB gap, for example, assuming a network-configured SB size of 8RBs. A similar process may be used to determine whether the first SB includes a valid CSI-RS resource presence based on a gap between an ending RB of a CSI-RS resource in the first SB and an ending RB of the first SB being less than or equal to a second threshold RB gap.

For example, as illustrated at 1202A, the UE may determine that the CSI-RS presence in a given SB of 8 RBs with a configured CSI-RS resource density of 1 is valid since the number of gap RBs in the SB (e.g., 2 RBs) is less than the configured first threshold RB gap (e.g., 3 RBs) . The UE may perform similar operations to determine an invalid CSI-RS resource presence in SBs that include a configured CSI-RS resource density of. 5, for example, as illustrated at 1204A.

In other cases, such as illustrated at 1206A, the UE may determine that the CSI-RS presence in a given SB of 3 RBs with a configured CSI-RS resource density of 1 is not valid since the number of gap RBs in the SB (e.g., 5 RBs) is greater than the configured first threshold RB gap (e.g., 3 RBs) . The UE may perform similar operations to determine an invalid CSI-RS resource presence in SBs that include a configured CSI-RS resource density of. 5, for example, as illustrated at 1208A.

Additionally, FIG. 12B illustrates various examples of determining a valid CSI-RS resource presence (e.g., for non-edge SBs) based on a gap between a starting RB of a CSI-RS resource in the first SB and a starting RB of the first SB being less than or equal to a first threshold RB gap, for example, assuming a network-configured SB size of 4RBs. As noted above, a similar process may be used to determine whether the first SB includes a valid CSI-RS resource presence based on a gap between an ending RB of a CSI-RS resource in the first SB and an ending RB of the first SB being less than or equal to a second threshold RB gap. According to aspects, operations performed by the UE for determining a valid CSI-RS resource corresponding to the network-configured SB size of 4RBs in FIG. 12B may be similar to the operations performed by the UE for determining a valid CSI-RS resource corresponding to the network-configured SB size of 8RBs in FIG. 12A.

Additionally, in some cases, determination of whether the first SB includes a valid CS-RS resource presence may also depend on an RB size of the first SB and a threshold size (e.g., especially for edge SBs as described above) . For example, even if the gap between a starting RB of a CSI-RS resource in the first SB and a starting RB of the first SB is less than or equal to a first threshold RB gap or the gap between an ending RB of a CSI-RS resource in the first SB and an ending RB of the first SB is less than or equal to a second threshold RB gap, the UE may determine that the first SB does not include a valid CSI-RS resource presence if the RB size of the first SB is not greater than or equal to the threshold size. For example, assuming the number RBs without CSI-RS resources in the first SB is less than or equal to the first RB threshold or a number of RBs with CSI-RS resources in the first SB is greater than or equal to the second SB threshold, if the RB size of the first SB is equal to 3RBs and the threshold size is equal to 5RBs, the UE may determine that the first SB does not include a valid CSI-RS resource presence.

FIG. 12C illustrates examples of determining a valid CSI-RS resource presence (e.g., for edge SBs) based on a gap between a starting RB of a CSI-RS resource in the first SB and a starting RB of the first SB being less than or equal to a first threshold RB gap, for example, assuming a network-configured SB size of 8RBs. A similar process may be used when the network-configured SB size is 4RBs.

For example, as illustrated at 1202C, the UE may determine that the CSI-RS presence in a given edge SB of 5 RBs with a configured CSI-RS resource density of 1 is valid since the number of gap RBs in the SB (e.g., 2 RBs) is less than the configured first threshold RB gap (e.g., 3 RBs) and since the number of RBs in the SB (e.g., 5) is equal to the threshold RB size (e.g., 5) . The UE may perform similar operations to determine an invalid CSI-RS resource presence in SBs that include a configured CSI-RS resource density of. 5, for example, as illustrated at 1204C.

In other cases, such as illustrated at 1206C, the UE may determine that the CSI-RS presence in a given SB of 3 RBs with a configured CSI-RS resource density of 1 is not valid since, while the number of gap RBs in the SB (e.g., 0 RBs) is less than the configured first threshold RB gap (e.g., 3 RBs) , the number of RBs in the SB (e.g., 3) is less than the threshold RB size (e.g., 5) . The UE may perform similar operations to determine an invalid CSI-RS resource presence in SBs that include a configured CSI-RS resource density of. 5, for example, as illustrated at 1208C.

In some cases, regardless of the threshold conditions, the UE may determine that the first SB does not include a valid CSI-RS presence based on the first SB only including a partial CSI-RS presence. In other words, the UE may treat any subband with partial CSI-RS presence as an invalid CSI reporting subband.

In some cases, the determination of whether the first SB includes a valid CSI-RS resource presence may depend on a type of CSI-RS resource configured in the CSI reporting configuration (e.g., transmitted by the base station to the UE) and a type of CSI-RS resource included in the first SB. For example, in some cases, the CSI reporting configuration may include one or more non-zero power CSI-RS resources for channel measurement (NZP CMR) . In such a case, the UE may determine that the first SB includes a valid CSI-RS presence only if the one or more NZP CMR for channel measurement satisfy the one or more threshold conditions described above.

Additionally, in some cases, the CSI reporting configuration may include one or more NZP CSI-RS resources for channel measurement and one or more CSI-interference measurement (CSI-IM) resources for interference measurement. Thus, in such a case, the UE may determine that the first SB includes a valid CSI-RS presence only if the one or more NZP CMR resources for channel measurement and the one or more CSI-IM resources for interference measurement satisfy the one or more threshold conditions described above.

Additionally, in some cases, the CSI reporting configuration may include one or more NZP CSI-RS resources for channel measurement (NZP CMR) , one or more CSI-interference measurement (CSI-IM) resources for interference measurement, and one or more NZP CSI-RS resources for interference measurement (NZP IMR) . According to aspects, in such a case, the UE may determine that the first SB includes a valid CSI-RS presence if, for when the first SB does not include an NZP CSI-RS for interference measurement, the one or more NZP CMR resources for channel measurement and the one or more CSI-IM resources for interference measurement satisfy the one or more threshold conditions, as described above. Otherwise, if the first SB includes an NZP CSI-RS for interference measurement, the UE may determine that the first SB comprises a valid CSI-RS presence if the one or more NZP CMR resources for channel measurement, the one or more CSI-IM resources for interference measurement, and the one or more NZP CSI-RS resources for interference measurement satisfy the one or more threshold conditions, as described above.

According to aspects, as noted above, if the UE determines that the first SB includes a valid CSI-RS resource presence, the UE may transmit a corresponding CSI report for the first SB. However, if the UE determines there is not a valid CSI-RS resource presence in the first SB, the UE may determine to take one or more actions, which may depend on a type of CSI to be reported. For example, for subband CSI, taking one or more actions may comprise one of (1) not transmitting the subband CSI for the first SB, (2) transmitting a subband CSI report of the first SB with information that the network would interpret as meaningless (e.g., a “garbage” CSI report) , or (3) treating the determination of a non-valid CSI-RS presence in the first SB as an error case. Additionally, for wideband CSI, taking one or more actions comprises one of (1) transmitting a wideband CSI report with only information corresponding to aggregation of one or more SBs with valid CSI-RS presence or (2) transmitting a wideband CSI report with information corresponding to frequency resources spanned by a CSI-RS.

FIG. 13 illustrates a communications device 1300 that may include various components (e.g., corresponding to means-plus-function components) configured to perform operations for the techniques disclosed herein, such as the operations illustrated in FIG. 9A and any other operations disclosed herein for channel state information (CSI) reporting without full channel state information reference signal (CSI-RS) presence in a subband. The communications device 1300 includes a processing system 1302 coupled to a transceiver 1308. The transceiver 1308 is configured to transmit and receive signals for the communications device 1300 via an antenna 1310, such as the various signal described herein. The processing system 1302 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 1302 includes a processor 1304 coupled to a computer-readable medium/memory 1312 via a bus 1306. In certain aspects, the computer-readable medium/memory 1312 is configured to store instructions that when executed by processor 1304, cause the processor 1304 to perform the operations illustrated in FIG. 9A, or other operations for performing the various techniques discussed herein for channel state information (CSI) reporting without full channel state information reference signal (CSI-RS) presence in a subband.

In certain aspects, the processor system 1302 further includes a receiver component 1314 for performing the operations illustrated in FIG. 9A at 902A. Additionally, the processing system 1302 includes a determination component 1316 for performing the operations illustrated in FIG. 9A at 904A. Additionally, the processing system 1302 includes a transmitter component 1318 for performing the operations illustrated in FIG. 9A at 906A. The receiver component 1314, determination component 1316, and the transmitter component 1322 may be coupled to the processor 1304 via bus 1306. In certain aspects, the receiver component 1314, determination component 1316, and the transmitter component 1322 may be hardware circuits. In certain aspects, the receiver component 1314, determination component 1316, and the transmitter component 1322 may be software components that are executed and run on processor 1304.

FIG. 14 illustrates a communications device 1400 that may include various components (e.g., corresponding to means-plus-function components) configured to perform operations for the techniques disclosed herein, such as the operations illustrated in FIG. 9B and any other operations disclosed herein for channel state information (CSI) reporting without full channel state information reference signal (CSI-RS) presence in a subband. The communications device 1400 includes a processing system 1302 coupled to a transceiver 1408. The transceiver 1408 is configured to transmit and receive signals for the communications device 1400 via an antenna 1410, such as the various signal described herein. The processing system 1402 may be configured to perform processing functions for the communications device 1400, including processing signals received and/or to be transmitted by the communications device 1400.

The processing system 1402 includes a processor 1404 coupled to a computer-readable medium/memory 1412 via a bus 1406. In certain aspects, the computer-readable medium/memory 1412 is configured to store instructions that when executed by processor 1404, cause the processor 1404 to perform the operations illustrated in FIG. 9B, or other operations for performing the various techniques discussed herein for channel state information (CSI) reporting without full channel state information reference signal (CSI-RS) presence in a subband.

In certain aspects, the processor system 1402 further includes a receiver component 1414 for performing the operations illustrated in FIG. 9B at 908B. Additionally, the processing system 1402 includes a determination component 1416 for performing the operations illustrated in FIG. 9B at 902B and 904B. Additionally, the processing system 1402 includes a transmitter component 1418 for performing the operations illustrated in FIG. 9B at 906B. The receiver component 1414, determination component 1416, and the transmitter component 1422 may be coupled to the processor 1404 via bus 1406. In certain aspects, the receiver component 1414, determination component 1416, and the transmitter component 1422 may be hardware circuits. In certain aspects, the receiver component 1414, determination component 1416, and the transmitter component 1422 may be software components that are executed and run on processor 1404.

The methods disclosed herein comprise one or more steps or actions for achieving the methods. The method steps and/or actions may be interchanged with one another without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and/or use of specific steps and/or actions may be modified without departing from the scope of the claims.

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.

The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language of the claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more. ” Unless specifically stated otherwise, the term “some” refers to one or more. All structural and functional equivalents 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 expressly incorporated herein by reference and 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. No claim element is to be construed under the provisions of 35 U.S.C. §112 (f) unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for. ”

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. Generally, where there are operations illustrated in figures, those operations may have corresponding counterpart means-plus-function components with similar numbering.

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, a digital signal processor (DSP) , an application specific integrated circuit (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 of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

If implemented in hardware, an example hardware configuration may comprise a processing system in a wireless node. The processing system may be implemented with a bus architecture. The bus may include any number of interconnecting buses and bridges depending on the specific application of the processing system and the overall design constraints. The bus may link together various circuits including a processor, machine-readable media, and a bus interface. The bus interface may be used to connect a network adapter, among other things, to the processing system via the bus. The network adapter may be used to implement the signal processing functions of the PHY layer. In the case of a UE 120 (see FIG. 1) , a user interface (e.g., keypad, display, mouse, joystick, etc. ) may also be connected to the bus. The bus may also link various other circuits such as timing sources, peripherals, voltage regulators, power management circuits, and the like, which are well known in the art, and therefore, will not be described any further. The processor may be implemented with one or more general-purpose and/or special-purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuitry that can execute software. Those skilled in the art will recognize how best to implement the described functionality for the processing system depending on the particular application and the overall design constraints imposed on the overall system.

If implemented in software, the functions may be stored or transmitted over as one or more instructions or code on a computer readable medium. Software shall be construed broadly to mean instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Computer-readable media include both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. The processor may be responsible for managing the bus and general processing, including the execution of software modules stored on the machine-readable storage media. A computer-readable storage medium may be coupled to a processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. By way of example, the machine-readable media may include a transmission line, a carrier wave modulated by data, and/or a computer readable storage medium with instructions stored thereon separate from the wireless node, all of which may be accessed by the processor through the bus interface. Alternatively, or in addition, the machine- readable media, or any portion thereof, may be integrated into the processor, such as the case may be with cache and/or general register files. Examples of machine-readable storage media may include, by way of example, RAM (Random Access Memory) , flash memory, ROM (Read Only Memory) , PROM (Programmable Read-Only Memory) , EPROM (Erasable Programmable Read-Only Memory) , EEPROM (Electrically Erasable Programmable Read-Only Memory) , registers, magnetic disks, optical disks, hard drives, or any other suitable storage medium, or any combination thereof. The machine-readable media may be embodied in a computer-program product.

A software module may comprise a single instruction, or many instructions, and may be distributed over several different code segments, among different programs, and across multiple storage media. The computer-readable media may comprise a number of software modules. The software modules include instructions that, when executed by an apparatus such as a processor, cause the processing system to perform various functions. The software modules may include a transmission module and a receiving module. Each software module may reside in a single storage device or be distributed across multiple storage devices. By way of example, a software module may be loaded into RAM from a hard drive when a triggering event occurs. During execution of the software module, the processor may load some of the instructions into cache to increase access speed. One or more cache lines may then be loaded into a general register file for execution by the processor. When referring to the functionality of a software module below, it will be understood that such functionality is implemented by the processor when executing instructions from that software module.

Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) , or wireless technologies such as infrared (IR) , radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, include compact disc (CD) , laser disc, optical disc, digital versatile disc (DVD) , floppy disk, and

disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Thus, in some aspects computer-readable media may comprise non-transitory computer-readable media (e.g., tangible media) . In addition, for other aspects computer-readable media may comprise transitory computer-readable media (e.g., a signal) . Combinations of the above should also be included within the scope of computer-readable media.

Thus, certain aspects may comprise a computer program product for performing the operations presented herein. For example, such a computer program product may comprise a computer-readable medium having instructions stored (and/or encoded) thereon, the instructions being executable by one or more processors to perform the operations described herein. For example, instructions for performing the operations described herein and illustrated in FIGs. 9A-12C.

Further, it should be appreciated that modules and/or other appropriate means for performing the methods and techniques described herein can be downloaded and/or otherwise obtained by a user terminal and/or base station as applicable. For example, such a device can be coupled to a server to facilitate the transfer of means for performing the methods described herein. Alternatively, various methods described herein can be provided via storage means (e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or floppy disk, etc. ) , such that a user terminal and/or base station can obtain the various methods upon coupling or providing the storage means to the device. Moreover, any other suitable technique for providing the methods and techniques described herein to a device can be utilized.

It is to be understood that the claims are not limited to the precise configuration and components illustrated above. Various modifications, changes and variations may be made in the arrangement, operation and details of the methods and apparatus described above without departing from the scope of the claims.

Claims

A method of wireless communication by a user equipment (UE) in a network, comprising:

receiving channel state information (CSI) reporting configuration information configuring the UE to perform CSI measurement and reporting, based on one or more CSI reference signals (CSI-RSs) , in one or more subbands (SBs) of a bandwidth part (BWP) of a system bandwidth;

determining if a first SB of the one or more SBs includes a valid CSI-RS presence based on whether one or more threshold conditions, involving CSI-RS resources included in the first SB, are satisfied; and

transmitting a CSI report corresponding to the first SB if it is determined that the first SB includes a valid CSI-RS presence.
The method of claim 1, wherein the first SB includes only a partial CSI-RS presence.
The method of claim 2, further comprising determining that the first SB does not include a valid CSI-RS presence based on the first SB only including a partial CSI-RS presence.
The method of claim 2, wherein the first SB includes the partial CSI-RS presence when one of:

an effective CSI-RS density of the first SB is less than a configured CSI-RS density for the first SB, wherein the effective CSI-RS density comprises a ratio between a number of resource blocks (RBs) of the first SB including CSI-RS resources and a total number of RBs included in the first SB;

a number of RBs with CSI-RS in the first SB is smaller than a number of RBs with CSI-RS with full CSI-RS presence, where the number of RBs with CSI-RS with full CSI-RS presence is equal to a number of RBs in the first SB multiplied by a configured CSI-RS density for the first SB;

a gap between a starting RB of CSI-RS resources in the first SB and a starting RB of the first SB is greater than a gap in a second SB with full CSI-RS presence; or

a gap between an ending RB of CSI-RS resources in the first SB and an ending RB of the first SB is greater than a gap in a second SB with full CSI-RS presence.
The method of claim 1, the one or more threshold conditions comprise an effective density of CSI-RS resources in the first SB being greater than or equal to a threshold.
The method of claim 5, wherein the effective density of CSI-RS resources comprises a ratio between a number of resource blocks (RBs) of the first SB including CSI-RS resources and a total number of RBs included in the first SB.
The method of claim 5, wherein:

the threshold comprises a first threshold value for a first configured CSI-RS density; and

the threshold comprises a second threshold value for a second configured CSI-RS density.
The method of claim 7, wherein the first threshold value and the second threshold value are configured by the network.
The method of claim 7, wherein the first threshold value and the second threshold value are fixed.
The method of claim 9, wherein at least one of the first threshold value or the second threshold value comprise a nominal CSI-RS density configured by the network.
The method of claim 1, wherein:

the CSI reporting configuration information includes one or more non-zero power CSI-RS resources for channel measurement; and

the first SB comprises a valid CSI-RS presence if the one or more non-zero power CSI-RS resources for channel measurement satisfy the one or more threshold conditions.
The method of claim 1, wherein:

the CSI reporting configuration information includes one or more non-zero power CSI-RS resources for channel measurement and one or more CSI-interference measurement resources for interference measurement; and

the first SB comprises a valid CSI-RS presence if the one or more non-zero power CSI-RS resources for channel measurement and the one or more CSI-interference measurement resources for interference measurement satisfy the one or more threshold conditions.
The method of claim 1, wherein:

the CSI reporting configuration information includes one or more non-zero power CSI-RS resources for channel measurement, one or more CSI-interference measurement resources for interference measurement, and one or more non-zero power CSI-RS resources for interference measurement; and

one of:

when the first SB does not include an non-zero power CSI-RS for interference measurement, the first SB comprises a valid CSI-RS presence when the one or more non-zero power CSI-RS resources for channel measurement and the one or more CSI-interference measurement resources for interference measurement satisfy the one or more threshold conditions; or

when the first SB includes an non-zero power CSI-RS for interference measurement, the first SB comprises a valid CSI-RS presence when the one or more non-zero power CSI-RS resources for channel measurement, the one or more CSI-interference measurement resources for interference measurement, and the one or more non-zero power CSI-RS resources for interference measurement satisfy the one or more threshold conditions.
The method of claim 1, further comprising taking one or more actions when it is determined that the first SB does not include a valid CSI-RS presence, wherein, for subband CSI, taking one or more actions comprises one of:

not transmitting the subband CSI of the first SB;

transmitting a subband CSI report of the first SB with information that the network would interpret as meaningless; or

treating the determination of a non-valid CSI-RS presence in the first SB as an error case.
A method of wireless communication by a base station in a network, comprising:

determining channel state information (CSI) reporting configuration information configuring a user equipment (UE) to perform CSI measurement and reporting, based on one or more CSI reference signals (CSI-RSs) , in one or more subbands (SBs) of a bandwidth part (BWP) of a system bandwidth, wherein the CSI reporting configuration information includes an SB size configuration;

determining a CSI-RS resource configuration associated with the CSI reporting configuration information;

transmitting the CSI reporting configuration information and the CSI-RS resource configuration to the UE; and

receiving a CSI report corresponding to a first SB if the first SB includes a valid CSI presence based on whether one or more threshold conditions, involving CSI-RS resources included in the first SB, are satisfied.
The method of claim 15, wherein the first SB includes only a partial CSI-RS presence.
The method of claim 16, wherein the first SB does not include a valid CSI-RS presence based on the first SB only including a partial CSI-RS presence.
The method of claim 16, wherein the first SB includes the partial CSI-RS presence when one of:

an effective CSI-RS density of the first SB is less than a configured CSI-RS density for the first SB, wherein the effective CSI-RS density comprises a ratio between a number of resource blocks (RBs) of the first SB including CSI-RS resources and a total number of RBs included in the first SB;

a number of RBs with CSI-RS in the first SB is smaller than a number of RBs with CSI-RS with full CSI-RS presence, where the number of RBs with CSI-RS with full CSI-RS presence is equal to a number of RBs in the first SB multiplied by a configured CSI-RS density for the first SB;

a gap between a starting RB of CSI-RS resources in the first SB and a starting RB of the first SB is greater than a gap in a second SB with full CSI-RS presence; or

a gap between an ending RB of CSI-RS resources in the first SB and an ending RB of the first SB is greater than a gap in a second SB with full CSI-RS presence.
The method of claim 15, the one or more threshold conditions comprise an effective density of CSI-RS resources in the first SB being greater than or equal to a threshold.
The method of claim 19, wherein the effective density of CSI-RS resources comprises a ratio between a number of resource blocks (RBs) of the first SB including CSI-RS resources and a total number of RBs included in the first SB.
The method of claim 19, wherein:

the threshold comprises a first threshold value for a first configured CSI-RS density; and

the threshold comprises a second threshold value for a second configured CSI-RS density.
The method of claim 21, further comprising transmitting an indication of the first threshold value and the second threshold value to the UE.
The method of claim 21, wherein the first threshold value and the second threshold value are fixed in a standards document.
The method of claim 23, wherein at least one of the first threshold value or the second threshold value comprises a nominal CSI-RS density.
The method of claim 15, wherein:

the CSI reporting configuration information includes one or more non-zero power CSI-RS resources for channel measurement; and

the first SB comprises a valid CSI-RS presence if the one or more non-zero power CSI-RS resources for channel measurement satisfy the one or more threshold conditions.
The method of claim 15, wherein:

the CSI reporting configuration information includes one or more non-zero power CSI-RS resources for channel measurement and one or more CSI-interference measurement resources for interference measurement; and

the first SB comprises a valid CSI-RS presence if the one or more non-zero power CSI-RS resources for channel measurement and the one or more CSI-interference measurement resources for interference measurement satisfy the one or more threshold conditions.
The method of claim 15, wherein:

the CSI reporting configuration information includes one or more non-zero power CSI-RS resources for channel measurement, one or more CSI-interference measurement resources for interference measurement, and one or more non-zero power CSI-RS resources for interference measurement; and

one of:

when the first SB does not include an non-zero power CSI-RS for interference measurement, the first SB comprises a valid CSI-RS presence when the one or more non-zero power CSI-RS resources for channel measurement and the one or more CSI-interference measurement resources for interference measurement satisfy the one or more threshold conditions; or

when the first SB includes an non-zero power CSI-RS for interference measurement, the first SB comprises a valid CSI-RS presence when the one or more non-zero power CSI-RS resources for channel measurement, the one or more CSI-interference measurement resources for interference measurement, and the one or more non-zero power CSI-RS resources for interference measurement satisfy the one or more threshold conditions.
The method of claim 15, wherein the first SB does not include a valid CSI-RS resource, and further comprising, for subband CSI, one of:

not receiving the subband CSI of the first SB; or

receiving a subband CSI report of the first SB with information that the base station would interpret as meaningless.
An apparatus for wireless communication by a user equipment (UE) in a network, comprising:

at least one processor configured to:

receive channel state information (CSI) reporting configuration information configuring the UE to perform CSI measurement and reporting, based on one or more CSI reference signals (CSI-RSs) , in one or more subbands (SBs) of a bandwidth part (BWP) of a system bandwidth;

determine if a first SB of the one or more SBs includes a valid CSI-RS presence based on whether one or more threshold conditions, involving CSI-RS resources included in the first SB, are satisfied; and

transmit a CSI report corresponding to the first SB if it is determined that the first SB includes a valid CSI-RS presence; and

a memory coupled with the at least one processor.
An apparatus for wireless communication by a base station in a network, comprising:

at least one processor configured to:

determine channel state information (CSI) reporting configuration information configuring a user equipment (UE) to perform CSI measurement and reporting, based on one or more CSI reference signals (CSI-RSs) , in one or more subbands (SBs) of a bandwidth part (BWP) of a system bandwidth, wherein the CSI reporting configuration information includes an SB size configuration;

determine a CSI-RS resource configuration associated with the CSI reporting configuration information;

transmit the CSI reporting configuration information and the CSI-RS resource configuration to the UE; and

receive a CSI report corresponding to a first SB if the first SB includes a valid CSI presence based on whether one or more threshold conditions, involving CSI-RS resources included in the first SB, are satisfied; and

a memory coupled with the at least one processor.