WO2023039695A1

WO2023039695A1 - Time domain related channel state information reports for wireless communication

Info

Publication number: WO2023039695A1
Application number: PCT/CN2021/118116
Authority: WO
Inventors: Runxin WANG; Yu Zhang; Muhammad Sayed Khairy Abdelghaffar; Hwan Joon Kwon
Original assignee: Qualcomm Incorporated
Priority date: 2021-09-14
Filing date: 2021-09-14
Publication date: 2023-03-23

Abstract

A user equipment (UE) can transmit multiple channel state information (CSI) reports that are related by certain differential functions such that the overhead for sending multiple CSI reports can be reduced. The UE receives a first channel state information reference signal (CSI-RS) from a scheduling entity. The UE transmits a first CSI report based on the first CSI-RS, the first CSI report comprising one or more first CSI components. The UE receives a second CSI-RS from the scheduling entity. The UE transmits a second CSI report based on the second CSI-RS and the first CSI report, the second CSI report comprising one or more second CSI components derived at least in part from the one or more first CSI components.

Description

TIME DOMAIN RELATED CHANNEL STATE INFORMATION REPORTS FOR WIRELESS COMMUNICATION

TECHNICAL FIELD

The technology discussed below relates generally to wireless communication systems, and more particularly, to time domain related channel state information (CSI) reports in wireless communication.

INTRODUCTION

Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on.Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources. Examples of such multiple-access technologies include 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. 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.

An example telecommunication standard is 5G New Radio (NR) . 5G NR is promulgated by Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with Internet of Things (IoT) ) , and other requirements. Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. As in LTE, a user equipment can transmit channel state information (CSI) reports to a 5G NR network. For example, a CSI report can include Channel Quality Information (CQI) , Precoding Matrix Indicator (PMI) , CSI-RS Resource Indicator (CRI) , Layer Indicator (LI) , and Rank Indicator (RI) , etc. CSI reporting can be periodic, aperiodic, and triggered.

SUMMARY OF SOME EXAMPLES

The following presents a summary of one or more aspects of the present disclosure, in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated features of the disclosure, and is intended neither to identify key or critical elements of all aspects of the disclosure nor to delineate the scope of any or all aspects of the disclosure. Its sole purpose is to present some concepts of one or more aspects of the disclosure in a form as a prelude to the more detailed description that is presented later.

One aspect of the disclosure provides a method for wireless communications by a user equipment (UE) . The method includes receiving a first channel state information reference signal (CSI-RS) from a scheduling entity. The method further includes transmitting a first CSI report based on the first CSI-RS, the first CSI report including one or more first CSI components. The method further includes receiving a second CSI-RS from the scheduling entity. The method further includes transmitting a second CSI report based on the second CSI-RS and the first CSI report, the second CSI report including one or more second CSI components derived at least in part from the one or more first CSI components.

Another aspect of the disclosure provides a method for wireless communications by a scheduling entity. The method includes transmitting a first channel state information reference signal (CSI-RS) to a user equipment (UE) . The method further includes receiving, from the UE, a first CSI report based on the first CSI-RS, the first CSI report including one or more first CSI components. The method further includes transmitting a second CSI-RS to the UE. The method further includes receiving, from the UE, a second CSI report based on the second CSI-RS and the first CSI report, the second CSI report including one or more second CSI components derived at least in part from the one or more first CSI components.

Another aspect of the disclosure provides a user equipment (UE) for wireless communication. The UE includes a transceiver configured for wireless communication, a memory, and a processor coupled with the transceiver and the memory. The processor and the memory are configured to receive a first channel state information reference signal (CSI-RS) from a scheduling entity. The processor and the memory are further configured to transmit a first CSI report based on the first CSI-RS, the first CSI report including one or more first CSI components. The processor and the memory are further configured to receive a second CSI-RS from the scheduling entity. The processor and the memory are further configured to transmit a second CSI report based on the second CSI-RS and the first CSI report, the second CSI report including one or more second CSI components derived at least in part from the one or more first CSI components.

Another aspect of the disclosure provides a scheduling entity for wireless communication. The scheduling entity includes a transceiver configured for wireless communication, a memory, and a processor coupled with the transceiver and the memory. The processor and the memory are configured to transmit a first channel state information reference signal (CSI-RS) to a user equipment (UE) . The processor and the memory are further configured to receive, from the UE, a first CSI report based on the first CSI-RS, the first CSI report including one or more first CSI components. The processor and the memory are further configured to transmit a second CSI-RS to the UE.The processor and the memory are further configured to receive, from the UE, a second CSI report based on the second CSI-RS and the first CSI report, the second CSI report including one or more second CSI components derived at least in part from the one or more first CSI components.

These and other aspects of the invention will become more fully understood upon a review of the detailed description, which follows. Other aspects, features, and implementations will become apparent to those of ordinary skill in the art, upon reviewing the following description of specific, exemplary implementations in conjunction with the accompanying figures. While features may be discussed relative to certain implementations and figures below, all implementations can include one or more of the advantageous features discussed herein. In other words, while one or more implementations may be discussed as having certain advantageous features, one or more of such features may also be used in accordance with the various implementations discussed herein. In similar fashion, while exemplary implementations may be discussed below as device, system, or method implementations, it should be understood that such exemplary implementations can be implemented in various devices, systems, and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a wireless communication system according to some aspects.

FIG. 2 is an illustration of an example of a radio access network according to some aspects.

FIG. 3 is a schematic illustration of an organization of wireless resources in an air interface utilizing orthogonal frequency divisional multiplexing (OFDM) according to some aspects.

FIG. 4 is a block diagram illustrating a wireless communication system supporting multiple-input multiple-output (MIMO) communication according to some aspects.

FIG. 5 illustrates an exemplary channel state information (CSI) resource mapping to support different report/measurement configurations according to some aspects.

FIG. 6 is a diagram illustrating multiple time domain related CSI reports according to some aspects.

FIG. 7 is a diagram illustrating a first process of generating channel quality indicator (CQI) values of a delta CSI report using a differential function according to some aspects.

FIG. 8 is a diagram illustrating a second process of generating channel quality indicator (CQI) values of a delta CSI report using a differential function according to some aspects.

FIG. 9 is a conceptual illustration of exemplary Type-II PMIs according to some aspects.

FIG. 10 is a conceptual illustration of exemplary eType-II PMIs according to some aspects.

FIG. 11 is a conceptual illustration of information contained in channel state feedback (CSF) according to some aspects.

FIG. 12 is a block diagram illustrating an example of a hardware implementation for a scheduling entity according to some aspects.

FIG. 13 is a flow chart illustrating an exemplary process at a scheduling entity for channel state feedback using time domain related CSI reports according to some aspects.

FIG. 14 is a block diagram conceptually illustrating an example of a hardware implementation for a scheduled entity according to some aspects.

FIG. 15 is a flow chart illustrating an exemplary process at a scheduled entity for channel state feedback using time domain related CSI reports according to some aspects.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

While aspects and implementations are described in this application by illustration to some examples, those skilled in the art will understand that additional implementations and use cases may come about in many different arrangements and scenarios. Innovations described herein may be implemented across many differing platform types, devices, systems, shapes, sizes, and packaging arrangements. For example, implementations and/or uses may come about via integrated chip examples and other non-module-component based devices (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail/purchasing devices, medical devices, AI-enabled devices, etc. ) . While some examples may or may not be specifically directed to use cases or applications, a wide assortment of applicability of described innovations may occur. Implementations may range a spectrum from chip-level or modular components to non-modular, non-chip-level implementations and further to aggregate, distributed, or OEM devices or systems incorporating one or more aspects of the described innovations. In some practical settings, devices incorporating described aspects and features may also necessarily include additional components and features for implementation and practice of claimed and described implementations. For example, transmission and reception of wireless signals necessarily includes a number of components for analog and digital purposes (e.g., hardware components including antenna, RF-chains, power amplifiers, modulators, buffer, processor (s) , interleaver, adders/summers, etc. ) . It is intended that innovations described herein may be practiced in a wide variety of devices, chip-level components, systems, distributed arrangements, end-user devices, etc. of varying sizes, shapes and constitutions.

Aspects of the disclosure provide apparatuses and methods of channel state information (CSI) feedback using multiple time domain related CSI reports. In some aspects, a user equipment (UE) can transmit multiple CSI reports that are related by certain differential functions such that the overhead for sending multiple CSI reports can be reduced.

The various concepts presented throughout this disclosure may be implemented across a broad variety of telecommunication systems, network architectures, and communication standards. Referring now to FIG. 1, as an illustrative example without limitation, various aspects of the present disclosure are illustrated with reference to a wireless communication system 100. The wireless communication system 100 includes three interacting domains: a core network 102, a radio access network (RAN) 104, and a user equipment (UE) 106. By virtue of the wireless communication system 100, the UE 106 may be enabled to carry out data communication with an external data network 110, such as (but not limited to) the Internet.

The RAN 104 may implement any suitable wireless communication technology or technologies to provide radio access to the UE 106. As one example, the RAN 104 may operate according to 3 ^rd Generation Partnership Project (3GPP) New Radio (NR) specifications, often referred to as 5G. As another example, the RAN 104 may operate under a hybrid of 5G NR and Evolved Universal Terrestrial Radio Access Network (eUTRAN) standards, often referred to as LTE. The 3GPP refers to this hybrid RAN as a next-generation RAN, or NG-RAN. Of course, many other examples may be utilized within the scope of the present disclosure.

As illustrated, the RAN 104 includes a plurality of base stations 108. Broadly, a base station is a network element in a radio access network responsible for radio transmission and reception in one or more cells to or from a UE. In different technologies, standards, or contexts, a base station may variously be referred to by those skilled in the art as a base transceiver station (BTS) , a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS) , an extended service set (ESS) , an access point (AP) , a Node B (NB) , an eNode B (eNB) , a gNode B (gNB) , a transmission and reception point (TRP) , or some other suitable terminology. In some examples, a base station may include two or more TRPs that may be collocated or non- collocated. Each TRP may communicate on the same or different carrier frequency within the same or different frequency band.

The radio access network 104 is further illustrated supporting wireless communication for multiple mobile apparatuses. A mobile apparatus may be referred to as user equipment (UE) in 3GPP standards, but may also be referred to by those skilled in the art as a mobile station (MS) , a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal (AT) , a mobile terminal, a wireless terminal, a remote terminal, a handset, a terminal, a user agent, a mobile client, a client, or some other suitable terminology. A UE may be an apparatus (e.g., a mobile apparatus) that provides a user with access to network services.

Within the present document, a “mobile” apparatus need not necessarily have a capability to move, and may be stationary. The term mobile apparatus or mobile device broadly refers to a diverse array of devices and technologies. UEs may include a number of hardware structural components sized, shaped, and arranged to help in communication; such components can include antennas, antenna arrays, RF chains, amplifiers, one or more processors, etc. electrically coupled to each other. For example, some non-limiting examples of a mobile apparatus include a mobile, a cellular (cell) phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal computer (PC) , a notebook, a netbook, a smartbook, a tablet, a personal digital assistant (PDA) , and a broad array of embedded systems, e.g., corresponding to an “Internet of things” (IoT) . A mobile apparatus may additionally be an automotive or other transportation vehicle, a remote sensor or actuator, a robot or robotics device, a satellite radio, a global positioning system (GPS) device, an object tracking device, a drone, a multi-copter, a quad-copter, a remote control device, a consumer and/or wearable device, such as eyewear, a wearable camera, a virtual reality device, a smart watch, a health or fitness tracker, a digital audio player (e.g., MP3 player) , a camera, a game console, etc. A mobile apparatus may additionally be a digital home or smart home device such as a home audio, video, and/or multimedia device, an appliance, a vending machine, intelligent lighting, a home security system, a smart meter, etc. A mobile apparatus may additionally be a smart energy device, a security device, a solar panel or solar array, a municipal infrastructure device controlling electric power (e.g., a smart grid) , lighting, water, etc.; an industrial automation and enterprise device; a logistics controller; agricultural equipment, etc. Still further, a mobile apparatus may provide for connected medicine or telemedicine support, e.g., health care at a distance. Telehealth devices may include telehealth monitoring devices and telehealth administration devices, whose communication may be given preferential treatment or prioritized access over other types of information, e.g., in terms of prioritized access for transport of critical service data, and/or relevant QoS for transport of critical service data.

Wireless communication between a RAN 104 and a UE 106 may be described as utilizing an air interface. Transmissions over the air interface from a base station (e.g., base station 108) to one or more UEs (e.g., UE 106) may be referred to as downlink (DL) transmission. In accordance with certain aspects of the present disclosure, the term downlink may refer to a point-to-multipoint transmission originating at a scheduling entity (described further below; e.g., base station 108) . Another way to describe this scheme may be to use the term broadcast channel multiplexing. Transmissions from a UE (e.g., UE 106) to a base station (e.g., base station 108) may be referred to as uplink (UL) transmissions. In accordance with further aspects of the present disclosure, the term uplink may refer to a point-to-point transmission originating at a scheduled entity (described further below; e.g., UE 106) .

In some examples, access to the air interface may be scheduled, wherein a scheduling entity (e.g., a base station 108) allocates resources for communication among some or all devices and equipment within its service area or cell. Within the present disclosure, as discussed further below, the scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more scheduled entities. That is, for scheduled communication, UEs 106, which may be scheduled entities, may utilize resources allocated by the scheduling entity 108.

Base stations 108 are not the only entities that may function as scheduling entities. That is, in some examples, a UE may function as a scheduling entity, scheduling resources for one or more scheduled entities (e.g., one or more other UEs) .

As illustrated in FIG. 1, a scheduling entity 108 may broadcast downlink traffic 112 to one or more scheduled entities 106. Broadly, the scheduling entity 108 is a node or device responsible for scheduling traffic in a wireless communication network, including the downlink traffic 112 and, in some examples, uplink traffic 116 from one or more scheduled entities 106 to the scheduling entity 108. On the other hand, the scheduled entity 106 is a node or device that receives downlink control information 114, including but not limited to scheduling information (e.g., a grant) , synchronization or timing information, or other control information from another entity in the wireless communication network such as the scheduling entity 108. The scheduled entity 106 may further transmit uplink control information 118, including but not limited to a scheduling request or feedback information, or other control information to the scheduling entity 108.

In addition, the uplink and/or downlink control information 114 and/or 118 and/or traffic information 112 and/or 116 may be transmitted on a waveform that may be time-divided into frames, subframes, slots, and/or symbols. As used herein, a symbol may refer to a unit of time that, in an orthogonal frequency division multiplexed (OFDM) waveform, carries one resource element (RE) per sub-carrier. A slot may carry 7 or 14 OFDM symbols. A subframe may refer to a duration of 1ms. Multiple subframes or slots may be grouped together to form a single frame or radio frame. Within the present disclosure, a frame may refer to a predetermined duration (e.g., 10 ms) for wireless transmissions, with each frame consisting of, for example, 10 subframes of 1 ms each. Of course, these definitions are not required, and any suitable scheme for organizing waveforms may be utilized, and various time divisions of the waveform may have any suitable duration.

In general, base stations 108 may include a backhaul interface for communication with a backhaul portion 120 of the wireless communication system. The backhaul 120 may provide a link between a base station 108 and the core network 102. Further, in some examples, a backhaul network may provide interconnection between the respective base stations 108. Various types of backhaul interfaces may be employed, such as a direct physical connection, a virtual network, or the like using any suitable transport network.

The core network 102 may be a part of the wireless communication system 100, and may be independent of the radio access technology used in the RAN 104. In some examples, the core network 102 may be configured according to 5G standards (e.g., 5GC) . In other examples, the core network 102 may be configured according to a 4G evolved packet core (EPC) , or any other suitable standard or configuration.

Referring now to FIG. 2, by way of example and without limitation, a schematic illustration of a RAN 200 is provided. In some examples, the RAN 200 may be the same as the RAN 104 described above and illustrated in FIG. 1. The geographic area covered by the RAN 200 may be divided into cellular regions (cells) that can be uniquely identified by a user equipment (UE) based on an identification broadcasted from one access point or base station. FIG. 2 illustrates

macrocells

202, 204, and 206, and a small cell 208, each of which may include one or more sectors (not shown) . A sector is a sub-area of a cell. All sectors within one cell are served by the same base station. A radio link within a sector can be identified by a single logical identification belonging to that sector. In a cell that is divided into sectors, the multiple sectors within a cell can be formed by groups of antennas with each antenna responsible for communication with UEs in a portion of the cell.

In FIG. 2, two base stations 210 and 212 are shown in

cells

202 and 204; and a third base station 214 is shown controlling a remote radio head (RRH) 216 in cell 206. That is, a base station can have an integrated antenna or can be connected to an antenna or RRH by feeder cables. In the illustrated example, the

cells

202, 204, and 126 may be referred to as macrocells, as the

base stations

210, 212, and 214 support cells having a large size. Further, a base station 218 is shown in the small cell 208 (e.g., a microcell, picocell, femtocell, home base station, home Node B, home eNode B, etc. ) which may overlap with one or more macrocells. In this example, the cell 208 may be referred to as a small cell, as the base station 218 supports a cell having a relatively small size. Cell sizing can be done according to system design as well as component constraints.

It is to be understood that the radio access network 200 may include any number of wireless base stations and cells. Further, a relay node may be deployed to extend the size or coverage area of a given cell. The

base stations

210, 212, 214, 218 provide wireless access points to a core network for any number of mobile apparatuses. In some examples, the

base stations

210, 212, 214, and/or 218 may be the same as the base station/scheduling entity 108 described above and illustrated in FIG. 1.

FIG. 2 further includes a quadcopter or drone 220, which may be configured to function as a base station. That is, 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 base station such as the quadcopter 220.

Within the RAN 200, the cells may include UEs that may be in communication with one or more sectors of each cell. Further, each

base station

210, 212, 214, 218, and 220 may be configured to provide an access point to a core network 102 (see FIG. 1) for all the UEs in the respective cells. For example, UEs 222 and 224 may be in communication with base station 210;

UEs

226 and 228 may be in communication with base station 212;

UEs

230 and 232 may be in communication with base station 214 by way of RRH 216; UE 234 may be in communication with base station 218; and UE 236 may be in communication with mobile base station 220. In some examples, the

UEs

222, 224, 226, 228, 230, 232, 234, 236, 238, 240, and/or 242 may be the same as the UE/scheduled entity 106 described above and illustrated in FIG. 1.

In some examples, a mobile network node (e.g., quadcopter 220) may be configured to function as a UE. For example, the quadcopter 220 may operate within cell 202 by communicating with base station 210.

In a further aspect of the RAN 200, sidelink signals may be used between UEs without necessarily relying on scheduling or control information from a base station. For example, two or more UEs (e.g.,

UEs

238, 240, and 242) may communicate with each other using peer-to-peer (P2P) or sidelink signals 237 without relaying that communication through a base station. In some examples, the

UEs

238, 240, and 242 may each function as a scheduling entity or transmitting sidelink device and/or a scheduled entity or a receiving sidelink device to schedule resources and communicate sidelink signals 237 therebetween without relying on scheduling or control information from a base station. In other examples, two or more UEs (e.g., UEs 226 and 228) within the coverage area of a base station (e.g., base station 212) may also communicate sidelink signals 227 over a direct link (sidelink) without conveying that communication through the base station 212. In this example, the base station 212 may allocate resources to the

UEs

226 and 228 for the sidelink communication. In either case, such sidelink signaling 227 and 237 may be implemented in a P2P network, a device-to-device (D2D) network, vehicle-to-vehicle (V2V) network, a vehicle-to-everything (V2X) , a mesh network, or other suitable direct link networks.

In the radio access network 200, the ability for a UE to communicate while moving, independent of its location, is referred to as mobility. The various physical channels between the UE and the radio access network are generally set up, maintained, and released under the control of an access and mobility management function (AMF, not illustrated, part of the core network 102 in FIG. 1) , which may include a security context management function (SCMF) and a security anchor function (SEAF) that perform authentication. The SCMF can manage, in whole or in part, the security context for both the control plane and the user plane functionality.

In various aspects of the disclosure, a radio access network 200 may utilize DL-based mobility or UL-based mobility to enable mobility and handovers (i.e., the transfer of a UE’s connection from one radio channel to another) . In a network configured for DL-based mobility, during a call with a scheduling entity, or at any other time, a UE may monitor various parameters of the signal from its serving cell as well as various parameters of neighboring cells. Depending on the quality of these parameters, the UE may maintain communication with one or more of the neighboring cells. During this time, if the UE moves from one cell to another, or if the signal quality from a neighboring cell exceeds that from the serving cell for a given amount of time, the UE may undertake a handoff or handover from the serving cell to the neighboring (target) cell. For example, UE 224 (illustrated as a vehicle, although any suitable form of UE may be used) may move from the geographic area corresponding to its serving cell 202 to the geographic area corresponding to a neighbor cell 206. When the signal strength or quality from the neighbor cell 206 exceeds that of its serving cell 202 for a given amount of time, the UE 224 may transmit a reporting message to its serving base station 210 indicating this condition. In response, the UE 224 may receive a handover command, and the UE may undergo a handover to the cell 206.

In a network configured for UL-based mobility, UL reference signals from each UE may be utilized by the network to select a serving cell for each UE. In some examples, the

base stations

210, 212, and 214/216 may broadcast unified synchronization signals (e.g., unified Primary Synchronization Signals (PSSs) , unified Secondary Synchronization Signals (SSSs) and unified Physical Broadcast Channels (PBCH) ) . The

UEs

222, 224, 226, 228, 230, and 232 may receive the unified synchronization signals, derive the carrier frequency and slot timing from the synchronization signals, and in response to deriving timing, transmit an uplink pilot or reference signal. The uplink pilot signal transmitted by a UE (e.g., UE 224) may be concurrently received by two or more cells (e.g., base stations 210 and 214/216) within the radio access network 200. Each of the cells may measure the strength of the pilot signal, and the radio access network (e.g., one or more of the base stations 210 and 214/216 and/or a central node within the core network) may determine a serving cell for the UE 224. As the UE 224 moves through the radio access network 200, the network may continue to monitor the uplink pilot signal transmitted by the UE 224. When the signal strength or quality of the pilot signal measured by a neighboring cell exceeds that of the signal strength or quality measured by the serving cell, the network 200 may hand over the UE 224 from the serving cell to the neighboring cell, with or without informing the UE 224.

Although the synchronization signal transmitted by the

base stations

210, 212, and 214/216 may be unified, the synchronization signal may not identify a particular cell, but rather may identify a zone of multiple cells operating on the same frequency and/or with the same timing. The use of zones in 5G networks or other next generation communication networks enables the uplink-based mobility framework and improves the efficiency of both the UE and the network, since the number of mobility messages that need to be exchanged between the UE and the network may be reduced.

The air interface in the radio access network 200 may utilize one or more duplexing algorithms. Duplex refers to a point-to-point communication link where both endpoints can communicate with one another in both directions. Full-duplex means both endpoints can simultaneously communicate with one another. Half-duplex means only one endpoint can send information to the other at a time. Half-duplex emulation is frequently implemented for wireless links utilizing time division duplex (TDD) . In TDD, transmissions in different directions on a given channel are separated from one another using time division multiplexing. That is, at some times the channel is dedicated for transmissions in one direction, while at other times the channel is dedicated for transmissions in the other direction, where the direction may change very rapidly, e.g., several times per slot. In a wireless link, a full-duplex channel generally relies on physical isolation of a transmitter and receiver, and suitable interference cancellation technologies. Full-duplex emulation is frequently implemented for wireless links by utilizing frequency division duplex (FDD) or spatial division duplex (SDD) . In FDD, transmissions in different directions may operate at different carrier frequencies (e.g., within paired spectrum) . In SDD, transmissions in different directions on a given channel are separated from one another using spatial division multiplexing (SDM) . In other examples, full-duplex communication may be implemented within unpaired spectrum (e.g., within a single carrier bandwidth) , where transmissions in different directions occur within different sub-bands of the carrier bandwidth. This type of full-duplex communication may be referred to herein as sub-band full duplex (SBFD) , also known as flexible duplex.

Further, the air interface in the radio access network 200 may utilize one or more multiplexing and multiple access algorithms to enable simultaneous communication of the various devices. For example, 5G NR specifications provide multiple access for UL transmissions from UEs 222 and 224 to base station 210, and for multiplexing for DL transmissions from base station 210 to one or more UEs 222 and 224, utilizing orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) . In addition, for UL transmissions, 5G NR specifications provide support for discrete Fourier transform-spread-OFDM (DFT-s-OFDM) with a CP (also referred to as single-carrier FDMA (SC-FDMA) ) . However, within the scope of the present disclosure, multiplexing and multiple access are not limited to the above schemes, and may be provided utilizing time division multiple access (TDMA) , code division multiple access (CDMA) , frequency division multiple access (FDMA) , sparse code multiple access (SCMA) , resource spread multiple access (RSMA) , or other suitable multiple access schemes. Further, multiplexing DL transmissions from the base station 210 to UEs 222 and 224 may be provided utilizing time division multiplexing (TDM) , code division multiplexing (CDM) , frequency division multiplexing (FDM) , orthogonal frequency division multiplexing (OFDM) , sparse code multiplexing (SCM) , or other suitable multiplexing schemes.

Various aspects of the present disclosure will be described with reference to an OFDM waveform, schematically illustrated in FIG. 3. It should be understood by those of ordinary skill in the art that the various aspects of the present disclosure may be applied to an SC-FDMA waveform in substantially the same way as described herein below. That is, while some examples of the present disclosure may focus on an OFDM link for clarity, it should be understood that the same principles may be applied as well to SC-FDMA waveforms.

Referring now to FIG. 3, an expanded view of an exemplary subframe 302 is illustrated, showing an OFDM resource grid. However, as those skilled in the art will readily appreciate, the PHY transmission structure for any particular application may vary from the example described here, depending on any number of factors. Here, time is in the horizontal direction with units of OFDM symbols; and frequency is in the vertical direction with units of subcarriers of the carrier.

The resource grid 304 may be used to schematically represent time–frequency resources for a given antenna port. That is, in a multiple-input-multiple-output (MIMO) implementation with multiple antenna ports available, a corresponding multiple number of resource grids 304 may be available for communication. The resource grid 304 is divided into multiple resource elements (REs) 306. An RE, which is 1 subcarrier × 1 symbol, is the smallest discrete part of the time–frequency grid, and contains a single complex value representing data from a physical channel or signal. Depending on the modulation utilized in a particular implementation, each RE may represent one or more bits of information. In some examples, a block of REs may be referred to as a physical resource block (PRB) or more simply a resource block (RB) 308, which contains any suitable number of consecutive subcarriers in the frequency domain. In one example, an RB may include 12 subcarriers, a number independent of the numerology used. In some examples, depending on the numerology, an RB may include any suitable number of consecutive OFDM symbols in the time domain. Within the present disclosure, it is assumed that a single RB such as the RB 308 entirely corresponds to a single direction of communication (either transmission or reception for a given device) .

A set of continuous or discontinuous resource blocks may be referred to herein as a Resource Block Group (RBG) , sub-band, or bandwidth part (BWP) . A set of sub-bands or BWPs may span the entire bandwidth. Scheduling of scheduled entities (e.g., UEs) for downlink, uplink, or sidelink transmissions typically involves scheduling one or more resource elements 306 within one or more sub-bands or bandwidth parts (BWPs) . Thus, a UE generally utilizes only a subset of the resource grid 304. In some examples, an RB may be the smallest unit of resources that can be allocated to a UE. Thus, the more RBs scheduled for a UE, and the higher the modulation scheme chosen for the air interface, the higher the data rate for the UE. The RBs may be scheduled by a scheduling entity, such as a base station (e.g., gNB, eNB, etc. ) , or may be self-scheduled by a UE implementing D2D sidelink communication.

In this illustration, the RB 308 is shown as occupying less than the entire bandwidth of the subframe 302, with some subcarriers illustrated above and below the RB 308. In a given implementation, the subframe 302 may have a bandwidth corresponding to any number of one or more RBs 308. Further, in this illustration, the RB 308 is shown as occupying less than the entire duration of the subframe 302, although this is merely one possible example.

Each 1 ms subframe 302 may consist of one or multiple adjacent slots. In the example shown in FIG. 3, one subframe 302 includes four slots 310, as an illustrative example. In some examples, a slot may be defined according to a specified number of OFDM symbols with a given cyclic prefix (CP) length. For example, a slot may include 7 or 14 OFDM symbols with a nominal CP. Additional examples may include mini-slots, sometimes referred to as shortened transmission time intervals (TTIs) , having a shorter duration (e.g., one to three OFDM symbols) . These mini-slots or shortened transmission time intervals (TTIs) may in some cases be transmitted occupying resources scheduled for ongoing slot transmissions for the same or for different UEs. Any number of resource blocks may be utilized within a subframe or slot.

An expanded view of one of the slots 310 illustrates the slot 310 including a control region 312 and a data region 314. In general, the control region 312 may carry control channels, and the data region 314 may carry data channels. Of course, a slot may contain all DL, all UL, or at least one DL portion and at least one UL portion. The structure illustrated in FIG. 3 is merely exemplary in nature, and different slot structures may be utilized, and may include one or more of each of the control region (s) and data region (s) .

Although not illustrated in FIG. 3, the various REs 306 within a RB 308 may be scheduled to carry one or more physical channels, including control channels, shared channels, data channels, etc. Other REs 306 within the RB 308 may also carry pilots or reference signals. These pilots or reference signals may provide for a receiving device to perform channel estimation of the corresponding channel, which may enable coherent demodulation/detection of the control and/or data channels within the RB 308.

In some examples, the slot 310 may be utilized for broadcast, multicast, groupcast, or unicast communication. For example, a broadcast, multicast, or groupcast communication may refer to a point-to-multipoint transmission by one device (e.g., a base station, UE, or other similar device) to other devices. Here, a broadcast communication is delivered to all devices, whereas a multicast or groupcast communication is delivered to multiple intended recipient devices. A unicast communication may refer to a point-to-point transmission by a one device to a single other device.

In an example of cellular communication over a cellular carrier via a Uu interface, for a DL transmission, the scheduling entity (e.g., a base station) may allocate one or more REs 306 (e.g., within the control region 312) to carry DL control information including one or more DL control channels, such as a physical downlink control channel (PDCCH) , to one or more scheduled entities (e.g., UEs) . The PDCCH carries downlink control information (DCI) including but not limited to power control commands (e.g., one or more open loop power control parameters and/or one or more closed loop power control parameters) , scheduling information, a grant, and/or an assignment of REs for DL and UL transmissions. The PDCCH may further carry HARQ feedback transmissions such as an acknowledgment (ACK) or negative acknowledgment (NACK) . HARQ is a technique well-known to those of ordinary skill in the art, wherein the integrity of packet transmissions may be checked at the receiving side for accuracy, e.g., utilizing any suitable integrity checking mechanism, such as a checksum or a cyclic redundancy check (CRC) . If the integrity of the transmission is confirmed, an ACK may be transmitted, whereas if not confirmed, a NACK may be transmitted. In response to a NACK, the transmitting device may send a HARQ retransmission, which may implement chase combining, incremental redundancy, etc.

The base station may further allocate one or more REs 306 (e.g., in the control region 312 or the data region 314) to carry other DL signals, such as a demodulation reference signal (DMRS) ; a phase-tracking reference signal (PT-RS) ; a channel state information (CSI) reference signal (CSI-RS) ; and a synchronization signal block (SSB) . SSBs may be broadcast at regular intervals based on a periodicity (e.g., 5, 10, 20, 30, 80, or 130 ms) . An SSB includes a primary synchronization signal (PSS) , a secondary synchronization signal (SSS) , and a physical broadcast control channel (PBCH) . A UE may utilize the PSS and SSS to achieve radio frame, subframe, slot, and symbol synchronization in the time domain, identify the center of the channel (system) bandwidth in the frequency domain, and identify the physical cell identity (PCI) of the cell.

The PBCH in the SSB may further include a master information block (MIB) that includes various system information, along with parameters for decoding a system information block (SIB) . The SIB may be, for example, a SystemInformationType 1 (SIB1) that may include various additional system information. The MIB and SIB1 together provide the minimum system information (SI) for initial access. Examples of system information transmitted in the MIB may include, but are not limited to, a subcarrier spacing (e.g., default downlink numerology) , system frame number, a configuration of a PDCCH control resource set (CORESET) (e.g., PDCCH CORESET0) , a cell barred indicator, a cell reselection indicator, a raster offset, and a search space for SIB1. Examples of remaining minimum system information (RMSI) transmitted in the SIB1 may include, but are not limited to, a random access search space, a paging search space, downlink configuration information, and uplink configuration information.

In an UL transmission, the scheduled entity (e.g., UE) may utilize one or more REs 306 to carry UL control information (UCI) including one or more UL control channels, such as a physical uplink control channel (PUCCH) , to the scheduling entity. UCI may include a variety of packet types and categories, including pilots, reference signals, and information configured to enable or assist in decoding uplink data transmissions. Examples of uplink reference signals may include a sounding reference signal (SRS) and an uplink DMRS. In some examples, the UCI may include a scheduling request (SR) , i.e., request for the scheduling entity to schedule uplink transmissions. Here, in response to the SR transmitted on the UCI, the scheduling entity may transmit downlink control information (DCI) that may schedule resources for uplink packet transmissions. UCI may also include HARQ feedback, channel state feedback (CSF) , such as a CSI report, or any other suitable UCI.

In addition to control information, one or more REs 306 (e.g., within the data region 314) may be allocated for data traffic. Such data traffic may be carried on one or more traffic channels, such as, for a DL transmission, a physical downlink shared channel (PDSCH) ; or for an UL transmission, a physical uplink shared channel (PUSCH) . In some examples, one or more REs 306 within the data region 314 may be configured to carry other signals, such as one or more SIBs and DMRSs.

In an example of sidelink communication over a sidelink carrier via a proximity service (ProSe) PC5 interface, the control region 312 of the slot 310 may include a physical sidelink control channel (PSCCH) including sidelink control information (SCI) transmitted by an initiating (transmitting) sidelink device (e.g., Tx V2X device or other Tx UE) towards a set of one or more other receiving sidelink devices (e.g., Rx V2X device or other Rx UE) . The data region 314 of the slot 310 may include a physical sidelink shared channel (PSSCH) including sidelink data traffic transmitted by the initiating (transmitting) sidelink device within resources reserved over the sidelink carrier by the transmitting sidelink device via the SCI. Other information may further be transmitted over various REs 306 within slot 310. For example, HARQ feedback information may be transmitted in a physical sidelink feedback channel (PSFCH) within the slot 310 from the receiving sidelink device to the transmitting sidelink device. In addition, one or more reference signals, such as a sidelink SSB, a sidelink CSI-RS, a sidelink SRS, and/or a sidelink positioning reference signal (PRS) may be transmitted within the slot 310.

These physical channels described above are generally multiplexed and mapped to transport channels for handling at the medium access control (MAC) layer. Transport channels carry blocks of information called transport blocks (TB) . The transport block size (TBS) , which may correspond to a number of bits of information, may be a controlled parameter, based on the modulation and coding scheme (MCS) and the number of RBs in a given transmission.

The channels or carriers illustrated in FIG. 3 are not necessarily all of the channels or carriers that may be utilized between devices, and those of ordinary skill in the art will recognize that other channels or carriers may be utilized in addition to those illustrated, such as other traffic, control, and feedback channels.

In some aspects of the disclosure, the scheduling entity and/or scheduled entity may be configured for beamforming and/or multiple-input multiple-output (MIMO) technology. FIG. 4 illustrates an example of a wireless communication system 400 supporting MIMO. In a MIMO system, a transmitter 402 includes multiple transmit antennas 404 (e.g., N transmit antennas) and a receiver 406 includes multiple receive antennas 408 (e.g., M receive antennas) . Thus, there are N × M signal paths 410 from the transmit antennas 404 to the receive antennas 408. Each of the transmitter 402 and the receiver 406 may be implemented, for example, within a scheduling entity 108, a scheduled entity 106, or any other suitable wireless communication device.

The use of such multiple antenna technology enables the wireless communication system to exploit the spatial domain to support spatial multiplexing, beamforming, and transmit diversity. Spatial multiplexing may be used to transmit different streams of data, also referred to as layers, simultaneously on the same time-frequency resource. The data streams may be transmitted to a single UE to increase the data rate or to multiple UEs to increase the overall system capacity, the latter being referred to as multi-user MIMO (MU-MIMO) . This is achieved by spatially precoding each data stream (i.e., multiplying the data streams with different weighting and phase shifting) and then transmitting each spatially precoded stream through multiple transmit antennas on the downlink. The spatially precoded data streams arrive at the UE (s) with different spatial signatures, which enables each of the UE (s) to recover the one or more data streams destined for that UE. On the uplink, each UE transmits a spatially precoded data stream, which enables the base station to identify the source of each spatially precoded data stream.

The number of data streams or layers corresponds to the rank of the transmission. In general, the rank of the MIMO system 400 is limited by the number of transmit or receive

antennas

404 or 408, whichever is lower. In addition, the channel conditions at the UE, as well as other considerations, such as the available resources at the base station, may also affect the transmission rank. For example, the rank (and therefore, the number of data streams) assigned to a particular UE on the downlink may be determined based on the rank indicator (RI) transmitted from the UE to the base station. The RI may be determined based on the antenna configuration (e.g., the number of transmit and receive antennas) and a measured signal-to-interference-and-noise ratio (SINR) on each of the receive antennas. The RI may indicate, for example, the number of layers that may be supported under the current channel conditions. The base station may use the RI, along with resource information (e.g., the available resources and amount of data to be scheduled for the UE) , to assign a transmission rank to the UE.

In Time Division Duplex (TDD) systems, the UL and DL are reciprocal, in that each uses different time slots of the same frequency bandwidth. Therefore, in TDD systems, the base station may assign the rank for DL MIMO transmissions based on UL SINR measurements (e.g., based on a Sounding Reference Signal (SRS) transmitted from the UE or other pilot signal) . Based on the assigned rank, the base station may then transmit CSI-RSs with separate C-RS sequences for each layer to provide for multi-layer channel estimation. From the CSI-RS, the UE may measure the channel quality across layers and resource blocks and feed back the RI and a channel quality indicator (CQI) that indicates to the base station a modulation and coding scheme (MCS) to use for transmissions to the UE for use in updating the rank and assigning REs for future downlink transmissions.

In the simplest case, as shown in FIG. 4, a rank-2 spatial multiplexing transmission on a 2x2 MIMO antenna configuration will transmit one data stream from each transmit antenna 404. Each data stream reaches each receive antenna 408 along a different signal path 410. The receiver 406 may then reconstruct the data streams using the received signals from each receive antenna 408.

CSI Reporting

FIG. 5 illustrates an exemplary CSI resource mapping to support different report/measurement configurations. The CSI resource mapping includes CSI report setting 502, CSI resource settings 504, CSI resource sets 506, and CSI resources 508. Each CSI resource setting 504 includes one or more CSI resource sets 506, and each CSI resource set 506 includes one or more CSI resources 508. In the example shown in FIG. 5, a single CSI resource setting (e.g., CSI resource setting 0) is illustrated. However, it should be understood that any suitable number of CSI resource settings 504 may be supported.

Each CSI report setting 502 may include a reportQuantity that indicates, for example, the specific CSI parameters and granularity thereof (e.g., wideband/sub-band CQI, PMI, RI, SLI, etc. ) , or L1 parameters (e.g., L1-RSRP, L1-SINR) to include in a CSI report. The CSI report setting 502 may further indicate a periodicity of the CSI report. For example, the CSI report setting 502 may indicate that the report should be generated periodically, aperiodically, or semi-persistently. For aperiodic CSI report settings, the CSI report may be sent on the PUSCH. For periodic CSI report settings, the CSI report may be sent on the PUCCH. For semi-persistent CSI report settings, the CSI report may be sent on the PUCCH or the PUSCH. For example, semi-persistent CSI reports sent on the PUCCH may be activated or deactivated using a medium access control (MAC) control element (MAC-CE) . Semi-persistent CSI reports sent on the PUSCH may be triggered using downlink control information (DCI) scrambled with a semi-persistent CSI (SP-CP) radio network temporary identifier (SP-CP-RNTI) . CSI report settings 502 may further include a respective priority and other suitable parameters.

Each CSI report setting 502 may be linked to a CSI resource setting 504. Each CSI resource setting 504 may be associated with a particular time domain behavior of reference signals. For example, each CSI resource setting 504 may include periodic, semi-persistent, or aperiodic CSI resources 508. For periodic and semi-persistent CSI resource settings 504, the number of configured CSI resource sets 506 may be limited to one. In general, the CSI resource settings 504 that may be linked to a particular CSI report setting 502 may be limited by the time domain behavior of the CSI resource setting 504 and the CSI report setting 502. For example, an aperiodic CSI report setting 502 may be linked to periodic, semi-persistent, or aperiodic CSI resource settings 504. However, a semi-persistent CSI report setting 502 may be linked to only periodic or semi-persistent CSI resource settings 504. In addition, a periodic CSI report setting 502 may be linked to only a periodic CSI resource setting 504.

Each CSI resource set 506 may be associated with a CSI resource type. For example, CSI resource types may include non-zero-power (NZP) CSI-RS resources, SSB resources, or channel state information interference measurement (CSI-IM) resources. Thus, the CSI resources 508 may include channel measurement resources (CMRs) , such as NZP CSI-RS or SSB resources, and/or interference measurement resources (IMRs) , such as CSI-IM resources. Each CSI resource set 506 includes a list of CSI resources 508 of a particular CSI resource type. In addition, each CSI resource set 506 may further be associated with one or more of a set of frequency resources (e.g., a bandwidth and/or OFDM symbol (s) within a slot) , a particular set of ports, a power, or other suitable parameters.

Each CSI resource 508 indicates the particular beam (e.g., ports) , frequency resource, and OFDM symbol on which the reference signal may be measured by the wireless communication device. For example, each CSI-RS resource 508 may indicate an RE on which a CSI-RS pilot or SSB transmitted from a particular set of ports (e.g., on a particular beam) may be measured. In the example shown in FIG. 5, CSI-RS resource set 0.1 includes four CSI-RS resources (CSI-RS resource 0.10, CSI-RS resource 0.11, CSI-RS resource 0.12, and CSI-RS resource 0.13) . Each CSI resource 508 may further be indexed by a respective beam identifier (ID) . The beam ID may identify not only the particular beam (e.g., ports) , but also the resources on which the reference signal may be measured. For example, the beam ID may include a CSI-RS resource indicator (CRI) or an SSB resource indicator (SSBRI) .

A scheduling entity (e.g., gNB) may configure a scheduled entity (e.g., UE) with one or more CSI report settings 502 and CSI resource settings 504 via, for example, radio resource control (RRC) signaling. For example, the scheduling entity may configure the scheduled entity with a list of periodic CSI report settings 502 indicating the associated CSI resource set 506 that the scheduled entity may utilize to generate periodic CSI reports. As another example, the scheduling entity may configure the scheduled entity with a list of aperiodic CSI report settings in a CSI-AperiodicTriggerStateList. Each trigger state in the CSI-AperiodicTriggerStateList may include a list of aperiodic CSI report settings 502 indicating the associated CSI resource sets 506 for channel (and optionally interference) measurement. As another example, the scheduling entity may configure the scheduled entity with a list of semi-persistent CSI report settings in a CSI-SemiPersistentOnPUSCH-TriggerStateList. Each trigger state in the CSI-SemiPersistentOnPUSCH-TriggerStateList may include one CSI report setting 502 indicating the associated CSI resource set 506. The scheduling entity may then trigger one or more of the aperiodic or semi-persistent trigger states using, for example, DCI. As indicated above, a MAC-CE may be used to activate or deactivate a semi-persistent CSI report setting 502 for a CSI report sent on the PUCCH.

For L1-RSRP measurement reports, the scheduled entity may be configured with a CSI resource setting 504 having up to sixteen CSI resource sets 506. For example, each of the CSI resource sets 506 may include up to sixty-four CSI resources 508 in each set. The total number of different CSI resources 508 over all the CSI resource sets 506 may be no more than 128. For L1-SINR measurement reports, the scheduled entity may be configured with a CSI resource setting 504 that can include up to 64 CSI resources 508 (e.g., up to 64 CSI-RS resources or up to 64 SSB resources) .

In some scenarios, a CSI report can be outdated and no longer accurately reflects the channel condition between a gNB and a UE when the channel condition changes significantly after the CSI-RS transmission and before DL data transmission. For example, the UE may be moving at high speed during the time delay. The time delay can be caused by channel estimation based on the CSI-RS, CSI report computation at the UE, and CSI report processing at the gNB. If the channel condition changes significantly during this time delay, the gNB cannot depend on the CSI report to predict the real-time channel condition.

In some aspects, a scheduling entity (e.g., base station 108 or gNB) can configure a scheduled entity (e.g., UE 106) to transmit CSI reports more frequently. FIG. 6 is a diagram illustrating multiple CSI reports transmitted between a UE and a base station in a time period according to some aspects. However, simply sending more CSI reports can increase signaling overhead. In some aspects, the base station (e.g., gNB) can configure the UE to transmit a reference CSI report 602 and one or more delta CSI reports based on CSI-RS 603 transmitted by the base station. Four exemplary delta CSI reports 604, 606, 608, and 610 are illustrated in FIG. 6. The delta CSI reports can be related to or based on the reference CSI report in the time domain such that the payload size of the delta CSI reports can be reduced relative to the reference CSI report. The delta CSI reports enable more frequent updates of the channel condition without significantly increasing the signaling overhead.

In some aspects, the delta CSI reports can be generated based on the reference CSI report 602 using certain differential functions or any suitable time domain functions to reduce the data payload or size of the delta CSI reports. In this disclosure, a differential function can determine a CSI component (e.g., RI, CQI, L1-RSRP, and PMI) of a delta CSI report based on a difference between the same CSI component and one or more components of a reference CSI report that is earlier in time than the delta CSI report. In some examples, a reference CSI report can be generated without depending on another CSI report that is earlier in time. Reducing the size of the delta CSI reports enables the UE to transmit multiple CSI reports without increasing overhead significantly. In one example, one or more components of a delta CSI report can be generated based on one or more components (e.g., RI, CQI, L1-RSRP, and PMI) of a reference CSI report using certain differential functions such that the payload size of the delta CSI report can be smaller than the reference CSI report.

Differential Channel Quality Information (CQI)

FIG. 7 is a diagram illustrating a process 700 of generating CQI values of a delta CSI report (e.g., delta CSI reports 604 to 610 of FIG. 6) using differential functions according to some aspects. Process 700 may be performed by any of the UE illustrated in FIGs. 1, 2, and 6. For example, a base station may configure a UE to report a wideband CQI and one or more sub-band CQIs (sub-band CQI 1 to sub-band CQI n) in a reference CSI report 702. The UE can include the values for the wideband CQI and sub-band CQIs for time T0 in the reference CSI report 702. Each sub-band CQI value can be determined by quantizing (e.g., quantization operator Q 704 in FIG. 7) the difference between the sub-band CQI and the wideband CQI to generate the corresponding CQI value in the CSI report 702. In one example, the wideband CQI can be subtracted from the sub-band CQI 1, and the difference is quantized to generate the corresponding sub-band CQI value (e.g., value 1) in the reference CSI report 702. An exemplary quantization table 706 is illustrated in FIG. 7 that can be used for quantizing or constraining the sub-band CQI values.

The UE can generate a delta CSI report 708 including wideband CQI and sub-bands CQIs for time T1 based on at least in part the reference CSI report 702 using certain differential functions. In one aspect, the wideband CQI value in the delta CSI report 708 can be based on the wideband CQI of time T1 and the wideband CQI value (A_0) of the reference CSI report 702; and the sub-band CQI values in the delta CSI report 708 can be based on the sub-band CQIs at T1 and the respective sub-band CQI values in the reference CSI report 702. For example, the wideband CQI value (value 0) of the delta CSI report 708 can be determined by quantizing (e.g., quantization operator Q 710) the difference between the wideband CQI of T1 and the wideband CQI value (e.g., W or A_0) in the reference CSI report 702. In one example, the quantization 710 may be performed based on the quantization table 706.

The sub-band CQI value (e.g., value 1) of the delta CSI report 708 can be determined by a certain differential function based on the sub-band CQI at T1 and wideband CQI and sub-band CQI at T1. In this example, the sub-band CQI value (e.g., value 1) of the reference CSI report 702 is dequantized 714 using a predetermined rule. The dequantization 714 may convert the sub-band CQI value in the CSI report back to the original sub-band CQI value or a similar value at T0. A sum (e.g., A_1) of the dequantized sub-band CQI value and the wideband CQI value (A_0) is used in a differential function 716 to determine the sub-band CQI value (e.g., value 1) in the delta CSI report 708. For example, the output of the differential function 716 is quantized 718 (e.g., using quantization operation Q’ in FIG. 7) to generate the sub-band CQI value (e.g., value 1) of the delta CSI report 708. An exemplary quantization table 720 that can be used for the quantization 718 is illustrated in FIG . 7.

Similar processes can be used to determine the other sub-band CQI values (e.g., value 1 to value n) in the delta CSI report 708 based on the wideband CQI, sub-band CQIs of T0, and sub-band CQIs of T1. Using the processes described above, the bit size or length of the CQI fields in the delta CSI report can be reduced, thus reducing signaling overhead in CSI reporting using the delta CSI report.

FIG. 8 is a diagram illustrating another process 800 of generating CQI values of a delta CSI report (e.g., CSI reports 604 to 610 of FIG. 6) using differential functions according to some aspects. Process 800 may be performed by any of the UEs illustrated in FIGs. 1, 2, and 6. For example, a base station (e.g., gNB) may configure a UE to report a wideband CQI and one or more sub-band CQIs (e.g., sub-band CQI 1 to sub-band CQI n) in a reference CSI report 802. The UE can include the CQI values (e.g., value 0 to value n) for the wideband CQI and sub-band CQIs of T0 in the reference CSI report 802. Each sub-band CQI value in the report 802 can be determined by quantizing (e.g., using quantization operator Q 804 in FIG. 8) the difference between the sub-band CQI and the wideband CQI. For example, the wideband CQI is subtracted from the sub-band CQI 1, and the difference is quantized to generate the corresponding sub-band CQI value (e.g., value 1) in the reference CSI report 802. An exemplary quantization table 806 is illustrated in FIG. 8 that can be used for quantizing the sub-band CQI values.

Then, the UE can generate a delta CSI report 808 including the wideband CQI and sub-band CQIs for time T1 (after T0) based on the CSI-RS and the reference CSI report 802 using certain differential functions. In one aspect, the wideband CQI value in the delta CSI report 808 of T1 can be based on the wideband CQI of time T1 and the wideband CQI value (A_0) of T0 from the reference CSI report 802. The sub-band CQI values (e.g., value 1 to value n) in the delta CSI report 808 are based on the sub-band CQIs at T1 and the wideband CQI value of the reference CSI report 802. For example, the wideband CQI value (value 0) of the delta CSI report 808 can be determined by quantizing 810 the difference between the wideband CQI at T1 and the wideband CQI value (e.g., W or A_0) of the reference CSI report 802. The quantization 810 may be based on the quantization table 806.

The sub-band CQI value (e.g., value 1 to value n) of the delta CSI report 808 can be determined based on a difference between the sub-band CQI of T1 and the wideband CQI value of the reference CSI report 802. For example, the wideband CQI value (A_0) of the reference CSI report 802 can be subtracted (e.g., differential function 812) from sub-band CQI 1 to determine the value 1 in the delta CSI report 808. In one example, the output of the differential function 812 can be quantized or constrained (e.g., using quantization operation Q’ 814 in FIG. 8) to generate the sub-band CQI value (e.g., value 1) of the delta CSI report 808. An exemplary quantization table 816 that can be used for the quantization 814 is illustrated in FIG . 8.

Similar processes can be used to determine the other sub-band CQI values (e.g., value 1 to value n) in the delta CSI report 808 based on the wideband CQI of T0 and sub-band CQIs of T1. Using the processes described above, the bit size or length of the CQI values in the delta CSI report can be reduced, thus reducing signaling overhead in CSI reporting.

Differential Precoding Matrix Indicator (PMI)

In some aspects, a delta CSI report (e.g., delta CSI reports described above in FIG. 6) may include a differential PMI to reduce the payload size (e.g., bit length) of the delta CSI report relative to a reference CSI report. Referring to FIG. 9, a reference CSI report (e.g., CSI report 602 of FIG. 6) may include a type-II PMI 902 that has various coefficients, for example, coefficients for beam indices (i _1, 1, i _1, 2) , strongest coefficient of each layer (i _1, 3) , amplitude coefficient indicators of each layer (i _1, 4) , phase coefficient indicators of each layer (i _2, 1) , and amplitude coefficient indicators (i _2, 2) . In one aspect, a differential PMI 904 may include, for example, differential coefficients (e.g., i _1, 1, i _1, 2) and non-differential (regular) coefficients (e.g., i _1, 3, i _1,4, i _2, 1, and i _2, ₂) . The differential coefficients can be represented using fewer bits than non-differential coefficients such that the differential PMI can have a smaller data size than the PMI of a reference CSI report. In one aspect, differential coefficients (e.g., i _1, 1, i _1, 2) can be determined using a circular differential function. For example, if the reference CSI report indicates i _1, 1 = 0 in the PMI, and the delta CSI report needs to indicate i _1, 1 = 15, the circular differential between the two PMI coefficients is 1 (assuming max i _1, 1 = 15) . In this case, the different PMI can indicate i _1, 1 = 1. Furthermore, differential coefficients (e.g., i _1, 1 and i _1, 2) can be quantized or constrained (e.g., 2-bit quantization) to reduce their bit size in the delta CSI report. In some aspects, a differential PMI can include one or more differential coefficients (e.g., i _1, 1, i _1, 2, i _1, 3, i _1, 4, i _2, 1, and i _2, 2) . In one aspect, a differential PMI can include fixed coefficients i _1, 1, i _1, 2 and one or more differential coefficients i _1, 3, i _1, 4, i _2, 1, i _2, ₂ and/or other PMI coefficients.

FIG. 10 is a drawing conceptually illustrating eType-II PMI 1002 and differential PMI 1004 according to some aspects. The PMI 1002 has various coefficients for, for example, beam indices (i _1, 1, i _1, 2) , frequency domain indices (i _1, 5, i _1, 6) , amplitude coefficient indicators (i _2, 3, i _2, 4) , phase coefficient indicators of each layer (i _2, 5) , amplitude/phase report indicators (i _1, 7) , and strongest coefficient of each layer (i _1, 8) . In one aspect, the differential PMI 1004 may include, for example, differential coefficients (e.g., i _1, 1, i _1, 2, i _1, 5, i _1, 6) and non-differential coefficients (e.g., i _2, 3, i _2, 4, i _2, 5, i _1, 7, i _1, 8) . In one aspect, the differential coefficients i _1, 1, i _1, 2, i _1, 5, i _1, 6 can be determined using a circular differential function as described above. Furthermore, differential coefficients i _1, 1, i _1, 2, i _1, 5, i _1, 6 can be quantized or constrained (e.g., 2 bit quantization) to reduce their bit size in the delta CSI report. In some aspects, a differential PMI can include one or more differential coefficients, for example, i _1, 1, i _1, 2, i _1, 5, i _1, 6 i _2, 3, i _2, 4, i _2, 5, i _1, 7, and i _1, 8. In one aspect, a differential PMI can include fixed coefficients i _1, 1, i _1, 2, i _1, 5, i _1, 6 and one or more differential coefficients i _2, 3, i _2, 4, i _2, 5, i _1, 7, and i _1, 8 and/or other coefficients.

In some aspects, a scheduling entity (e.g., gNB or base station) can configure (e.g., using RRC or DCI signaling) the UE to report different PMIs coefficients using different periodicities. Referring back to FIG. 6, a gNB can configure a UE to report multiple CSI-reports (e.g., reference CSI report 602 and one or more delta CSI reports) . In response, the UE can transmit a reference CSI report that is followed by multiple delta CSI reports (e.g., delta CSI reports 604, 606, 608, and 610) . In one aspect, the UE can use a longer periodicity for reporting certain PMI coefficients, for example, in a Type-I PMI and Type II PMI. For example, the UE can include PMI coefficients for beam indices (e.g., i _1, 1 and i _1, 2) in the reference CSI report 602, but not in one or more delta CSI reports. In one aspect, the UE can use a longer periodicity for reporting certain PMI coefficients of a eType-II PMI. For example, the UE can include PMI coefficients i _1, 1, i _1, 2, i _1, 5, i _1, 6 in the reference CSI report 602, but not in the delta CSI reports. The scheduling entity/UE can determine the non-reported PMI coefficients (e.g., i _1, 1, i _1, 2, i _1, 5, i _1, 6) of a PMI based on other coefficients included in the same PMI using a predetermined rule available to the UE/scheduling entity. For example, the predetermined rule can be defined in a communication standing (e.g., 5G NR) governing the communication between the scheduling entity and the UE. In some examples, the scheduling entity can configure the CSI reports using persistent or semi-persistent scheduling (e.g., RRC) and trigger the reference CSI report and/or delta CSI reports using dynamic signaling (e.g., DCI) .

In some aspects, a UE can send channel state feedback (CSF) (e.g., CSI reports 602 to 610 of FIG. 6) in uplink control information (UCI) . For example, CSF may include various CSI fields for a reference CSI report and/or delta CSI reports. CSF can include various information that can indicate channel condition, for example, CRI, RI, LI, PMI, CQI, SSBRI, RSRP, SINR, etc. for a reference CSI report. FIG. 11 is a drawing conceptually illustrating some information carried by a CSF 1100 according to some aspects. The CSF 1100 may include CSI fields for a delta CSI report, for example, differential CRI (dCRI) 1102, differential RI (dRI) 1104, differential PMI (dPMI) 1106, differential QCI (dQCI) 1108, and differential LI (dLI) 1110. The dCRI 1102 field can be determined based on the CRI of a reference CSI report using a differential function. The dRI 1104 field can be determined based on the RI of a reference CSI report using a differential function. The dPMI field 1106 can be determined based on the PMI of a reference CSI report using a differential function. The dCQI field 1108 can be determined based on the CQI of a reference CSI report using a differential function. The dLI field 1110 can be determined based on the LI of a reference CSI report using a differential function. In some aspects, the UE can determine the values of dCRI, dRI, dPMI, dQCI, and dLI using differential processes similar to those described above in relation to FIGs. 6–10. The base station can configure the UE to use various CSF formats to transmit a reference CSI report and/or one or more delta reference CSI reports. In one aspect, the UE can transmit a delta CSI report individually or together with a reference CSI report in the same UCI. In an exemplary CSF, the CSI fields can be arranged in the order of dCRI, dRI, dLI, zero padding (if needed) , dPMI, and dCQI. In another exemplary CSF, the CSI fields can be arranged in the order of CRI, dCRI, RI, dRI, LI, dLI, zero padding (if needed) , PMI, dPMI, CQI, and dCQI. The specific order of the above CSI fields may improve the processing time or efficiency of the CSI reports.

FIG. 12 is a block diagram illustrating an example of a hardware implementation for a scheduling entity 1200 employing a processing system 1214. For example, the scheduling entity 1200 may be a base station or gNB as illustrated in any one or more of FIGs. 1, 2, and/or 6.

The scheduling entity 1200 may be implemented with a processing system 1214 that includes one or more processors 1204. Examples of processors 1204 include microprocessors, microcontrollers, digital signal processors (DSPs) , field programmable gate arrays (FPGAs) , programmable logic devices (PLDs) , state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. In various examples, the scheduling entity 1200 may be configured to perform any one or more of the functions described herein. That is, the processor 1204, as utilized in a scheduling entity 1200, may be used to implement any one or more of the processes and procedures described below and illustrated in FIG. 13.

The processor 1204 may in some instances be implemented via a baseband or modem chip and in other implementations, the processor 1204 may include a number of devices distinct and different from a baseband or modem chip (e.g., in such scenarios as may work in concert to achieve examples discussed herein) . And as mentioned above, various hardware arrangements and components outside of a baseband modem processor can be used in implementations, including RF-chains, power amplifiers, modulators, buffers, interleavers, adders/summers, etc.

In this example, the processing system 1214 may be implemented with a bus architecture, represented generally by the bus 1202. The bus 1202 may include any number of interconnecting buses and bridges depending on the specific application of the processing system 1214 and the overall design constraints. The bus 1202 communicatively couples together various circuits including one or more processors (represented generally by the processor 1204) , a memory 1205, and computer-readable media (represented generally by the computer-readable medium 1206) . The bus 1202 may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further. A bus interface 1208 provides an interface between the bus 1202 and a transceiver 1210. The transceiver 1210 provides a communication interface or means for communicating with various other apparatus over a transmission medium. Depending upon the nature of the apparatus, a user interface 1212 (e.g., keypad, display, speaker, microphone, joystick) may also be provided. Of course, such a user interface 1212 is optional, and may be omitted in some examples, such as a base station.

The processor 1204 is responsible for managing the bus 1202 and general processing, including the execution of software stored on the computer-readable medium 1206. The software, when executed by the processor 1204, causes the processing system 1214 to perform the various functions described below for any particular apparatus. The computer-readable medium 1206 and the memory 1205 may also be used for storing data that is manipulated by the processor 1204 when executing software.

One or more processors 1204 in the processing system may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. The software may reside on a computer-readable medium 1206. The computer-readable medium 1206 may be a non-transitory computer-readable medium. A non-transitory computer-readable medium includes, by way of example, a magnetic storage device (e.g., hard disk, floppy disk, magnetic strip) , an optical disk (e.g., a compact disc (CD) or a digital versatile disc (DVD) ) , a smart card, a flash memory device (e.g., a card, a stick, or a key drive) , a random access memory (RAM) , a read only memory (ROM) , a programmable ROM (PROM) , an erasable PROM (EPROM) , an electrically erasable PROM (EEPROM) , a register, a removable disk, and any other suitable medium for storing software and/or instructions that may be accessed and read by a computer. The computer-readable medium 1206 may reside in the processing system 1214, external to the processing system 1214, or distributed across multiple entities including the processing system 1214. The computer-readable medium 1206 may be embodied in a computer program product. By way of example, a computer program product may include a computer-readable medium in packaging materials. Those skilled in the art will recognize how best to implement the described functionality presented throughout this disclosure depending on the particular application and the overall design constraints imposed on the overall system.

In some aspects of the disclosure, the processor 1204 may include circuitry configured for various functions, including, for example, channel state estimation and feedback. For example, the circuitry may be configured to implement one or more of the functions described below in relation to FIG. 13.

In some aspects of the disclosure, the processor 1204 may include communication and processing circuitry 1240 configured for various functions, including for example communicating with a network core (e.g., a 5G core network) , scheduled entities (e.g., UE) , or any other entity, such as, for example, local infrastructure or an entity communicating with the scheduling entity 1200 via the Internet, such as a network provider. In some examples, the communication and processing circuitry 1240 may include one or more hardware components that provide the physical structure that performs processes related to wireless communication (e.g., signal reception and/or signal transmission) and signal processing (e.g., processing a received signal and/or processing a signal for transmission) . For example, the communication and processing circuitry 1240 may include one or more transmit/receive chains. In addition, the communication and processing circuitry 1240 may be configured to receive and process uplink traffic and uplink control messages (e.g., similar to uplink traffic 116 and uplink control 118 of FIG. 1) , transmit and process downlink traffic and downlink control messages (e.g., similar to downlink traffic 112 and downlink control 114) . The communication and processing circuitry 1240 may further be configured to execute communication and processing software 1252 stored on the computer-readable medium 1206 to implement one or more functions described herein.

In some implementations where the communication involves receiving information, the communication and processing circuitry 1240 may obtain information from a component of the wireless communication device 1200 (e.g., from the transceiver 1210 that receives the information via radio frequency signaling or some other type of signaling suitable for the applicable communication medium) , process (e.g., decode) the information, and output the processed information. For example, the communication and processing circuitry 1240 may output the information to another component of the processor 1204, to the memory 1205, or to the bus interface 1208. In some examples, the communication and processing circuitry 1240 may receive one or more of signals, messages, other information, or any combination thereof. In some examples, the communication and processing circuitry 1240 may receive information via one or more channels. In some examples, the communication and processing circuitry 1240 may include functionality for a means for receiving. In some examples, the communication and processing circuitry 1240 may include functionality for a means for processing, including a means for demodulating, a means for decoding, etc.

In some implementations where the communication involves sending (e.g., transmitting) information, the communication and processing circuitry 1240 may obtain information (e.g., from another component of the processor 1204, the memory 1205, or the bus interface 1208) , process (e.g., modulate, encode, etc. ) the information, and output the processed information. For example, the communication and processing circuitry 1240 may output the information to the transceiver 1210 (e.g., that transmits the information via radio frequency signaling or some other type of signaling suitable for the applicable communication medium) . In some examples, the communication and processing circuitry 1240 may send one or more of signals, messages, other information, or any combination thereof. In some examples, the communication and processing circuitry 1240 may send information via one or more channels. In some examples, the communication and processing circuitry 1240 may include functionality for a means for sending (e.g., a means for transmitting) . In some examples, the communication and processing circuitry 1240 may include functionality for a means for generating, including a means for modulating, a means for encoding, etc.

In some aspects of the disclosure, the processor 1204 may include channel state information circuitry 1242 configured for various functions, for example, generating reference signals (e.g., CSI-RS) and processing CSI report for channel estimation and measurement. The channel state information circuitry 1242 can be configured to allocate resources (e.g., time, frequency, and spatial references) for reference signals (e.g., CSI-RS) transmission and configure a UE to estimate and report the channel condition based on the reference signals. The channel state information circuitry 1242 can be configured to process CSI reports, for example, a reference CSI report and one or more delta CSI reports. The channel state information circuitry 1242 may further be configured to execute channel state information software 1254 stored on the computer-readable medium 1206 to implement one or more functions described herein.

FIG. 13 is a flow chart illustrating an exemplary process 1300 for channel state feedback in accordance with some aspects of the present disclosure. As described below, some or all illustrated features may be omitted in a particular implementation within the scope of the present disclosure, and some illustrated features may not be required for all implementations. In some examples, the process 1300 may be carried out by the scheduling entity 1200 illustrated in FIG. 12. In some examples, the process 1300 may be carried out by any suitable apparatus or means for carrying out the functions or algorithm described below.

At block 1302, a scheduling entity (e.g., gNB) transmits a first channel state information reference signal (CSI-RS) to a UE. In one aspect, the communication and processing circuitry 1240 can provide a means to transmit the first CSI-RS using the transceiver 1210. In one example, the first CSI-RS may be the CSI-RS 603 of FIG. 6 or any suitable reference signals for channel estimation. The CSI-RS can be used for measuring the channel quality between the scheduling entity and the UE. In one aspect, the channel state information circuitry 1242 can provide a means to prepare and allocate resources (e.g., time, frequency, and spatial resources) for the transmission of the first CSI-RS.

At block 1304, the scheduling entity receives a first CSI report based on the first CSI-RS from the UE. In one aspect, the communication and processing circuitry 1240 can provide a means to receive the first CSI report using the transceiver 1210. In one example, the first CSI report may be a reference or full CSI report (e.g., reference CSI report 602 of FIG. 6) as described above. In one example, the first CSI report can include one or more first CSI components, for example, CRI, RI, LI, PMI, and CQI, based on the first CSI-RS.

At block 1306, the scheduling entity transmits a second CSI-RS to the UE. In one aspect, the communication and processing circuitry 1240 can provide a means to transmit the second CSI-RS after the first CSI-RS. In one example, the second CSI-RS may be the CSI-RS 603 of FIG. 6. The second CSI-RS enables the UE to perform channel estimation on the wireless channel between the scheduling entity and the UE. In one aspect, the channel state information circuitry 1242 can provide a means to prepare and allocate resources (e.g., time, frequency, and spatial resources) for the transmission of reference signals, for example, the second CSI-RS.

At block 1308, the scheduling entity receives a second CSI report based on the second CSI-RS and the first CSI report from the UE. The first CSI report and the second CSI report are related in the time domain. For example, the second CSI report can include one or more second CSI components derived at least in part from one or more first CSI components of the first CSI report. In one aspect, the communication and processing circuitry 1240 can provide a means to receive the second CSI report via the transceiver 1210. In one example, the second CSI report may be a delta CSI report (e.g., delta CSI report 604 of FIG. 6) . The second CSI report can include one or more second CSI components, for example, dCRI, dRI, dLI, dPMI, and dCQI, based on the second CSI-RS and at least in part on one or more first CSI components, for example, CRI, RI, LI, PMI, and CQI. In one aspect, the channel state information circuitry 1242 can provide a means to estimate the channel using both the first CSI report and the second CSI report.

In one configuration, the apparatus 1200 for wireless communication includes means for performing the above described processes of FIG. 13. In one aspect, the aforementioned means may be the processor 1204 shown in FIG. 12 configured to perform the functions recited by the aforementioned means. In another aspect, the aforementioned means may be a circuit or any apparatus configured to perform the functions recited by the aforementioned means.

Of course, in the above examples, the circuitry included in the processor 1204 is merely provided as an example, and other means for carrying out the described functions may be included within various aspects of the present disclosure, including but not limited to the instructions stored in the computer-readable storage medium 1206, or any other suitable apparatus or means described in any one of the FIGs. 1, 2, and/or 6, and utilizing, for example, the processes and/or algorithms described herein in relation to FIG. 13.

FIG. 14 is a conceptual diagram illustrating an example of a hardware implementation for an exemplary scheduled entity 1400 employing a processing system 1414. In accordance with various aspects of the disclosure, an element, or any portion of an element, or any combination of elements may be implemented with a processing system 1414 that includes one or more processors 1404. For example, the scheduled entity 1400 may be a user equipment (UE) as illustrated in any one or more of FIGs. 1, 2, and/or 6.

The processing system 1414 may be substantially the same as the processing system 1214 illustrated in FIG. 12, including a bus interface 1408, a bus 1402, memory 1405, a processor 1404, and a computer-readable medium 1406. Furthermore, the scheduled entity 1400 may include a user interface 1412 and a transceiver 1410 substantially similar to those described above in FIG. 12. That is, the processor 1404, as utilized in a scheduled entity 1400, may be used to implement any one or more of the processes described below and illustrated in FIG. 15.

In some aspects of the disclosure, the processor 1404 may include communication and processing circuitry 1440 configured for various functions, including for example communicating with a scheduling entity (e.g., base station, gNB) . In some examples, the communication and processing circuitry 1440 may include one or more hardware components that provide the physical structure that performs processes related to wireless communication (e.g., signal reception and/or signal transmission) and signal processing (e.g., processing a received signal and/or processing a signal for transmission) . For example, the communication and processing circuitry 1440 may include one or more transmit/receive chains. In addition, the communication and processing circuitry 1440 may be configured to transmit and process uplink traffic and uplink control messages (e.g., similar to uplink traffic 116 and uplink control 118 of FIG. 1) , receive and process downlink traffic and downlink control messages (e.g., similar to downlink traffic 112 and downlink control 114) . The communication and processing circuitry 1440 may further be configured to execute communication and processing software 1452 stored on the computer-readable medium 1406 to implement one or more functions described herein.

In some implementations where the communication involves receiving information, the communication and processing circuitry 1440 may obtain information from a component of the wireless communication device 1400 (e.g., from the transceiver 1410 that receives the information via radio frequency signaling or some other type of signaling suitable for the applicable communication medium) , process (e.g., decode) the information, and output the processed information. For example, the communication and processing circuitry 1440 may output the information to another component of the processor 1404, to the memory 1405, or to the bus interface 1408. In some examples, the communication and processing circuitry 1440 may receive one or more of signals, messages, other information, or any combination thereof. In some examples, the communication and processing circuitry 1440 may receive information via one or more channels. In some examples, the communication and processing circuitry 1440 may include functionality for a means for receiving. In some examples, the communication and processing circuitry 1440 may include functionality for a means for processing, including a means for demodulating, a means for decoding, etc.

In some implementations where the communication involves sending (e.g., transmitting) information, the communication and processing circuitry 1440 may obtain information (e.g., from another component of the processor 1404, the memory 1405, or the bus interface 1408) , process (e.g., modulate, encode, etc. ) the information, and output the processed information. For example, the communication and processing circuitry 1440 may output the information to the transceiver 1410 (e.g., that transmits the information via radio frequency signaling or some other type of signaling suitable for the applicable communication medium) . In some examples, the communication and processing circuitry 1440 may send one or more of signals, messages, other information, or any combination thereof. In some examples, the communication and processing circuitry 1440 may send information via one or more channels. In some examples, the communication and processing circuitry 1440 may include functionality for a means for sending (e.g., a means for transmitting) . In some examples, the communication and processing circuitry 1440 may include functionality for a means for generating, including a means for modulating, a means for encoding, etc.

In some aspects of the disclosure, the processor 1404 may include channel state feedback circuitry 1442 configured for various functions, for example, measuring and estimating channel condition based on reference signals (e.g., CSI-RS) transmitted by the scheduling entity. The channel state feedback circuitry 1442 can generate multiple time-domain related CSI reports, for example, a reference CSI report and one or more delta CSI reports as described above in relation to FIGs. 6–11. For example, the channel state feedback circuitry 1442 can generate a delta CSI report based on a reference CSI report using a differential function. In one example, the channel state feedback circuitry 1442 can generate a delta CSI report including dCRI, dRI, dPMI, dQCI, and/or dLI. The channel state feedback circuitry 1442 may further be configured to execute channel state feedback software 1454 stored on the computer-readable medium 1406 to implement one or more functions described herein.

FIG. 15 is a flow chart illustrating an exemplary process 1500 for channel state feedback in accordance with some aspects of the present disclosure. As described below, some or all illustrated features may be omitted in a particular implementation within the scope of the present disclosure, and some illustrated features may not be required for all implementations. In some examples, the process 1500 may be carried out by the scheduled entity 1400 illustrated in FIG. 14. In some examples, the process 1500 may be carried out by any suitable apparatus or means for carrying out the functions or algorithm described below.

At block 1502, a scheduled entity (e.g., UE) receives a first CSI-RS from a scheduling entity (e.g., gNB) . In one aspect, the communication and processing circuitry 1440 can provide a means to receive the first CSI-RS using the transceiver 1410. In one example, the first CSI-RS may be the CSI-RS 603 of FIG. 6 or any reference signal suitable for channel estimation. Based on the first CSI-RS, the scheduled entity can measure or estimate a wireless channel between the scheduled entity and the scheduling entity. In one aspect, the channel state feedback circuitry 1442 can provide a means to estimate the channel using the first CSI-RS and generate a CSI report to provide channel state feedback (CSF) to the scheduling entity.

At block 1504, the scheduled entity transmits a first CSI report based on the first CSI-RS to the scheduling entity. In one aspect, the communication and processing circuitry 1440 can provide a means to transmit the first CSI report using the transceiver 1410. In one example, the first CSI report may be a reference CSI report (e.g., reference CSI report 602 of FIG. 6) . The first CSI report can include one or more first CSI components, for example, CRI, RI, LI, PMI, and CQI, based on the first CSI-RS.

At block 1506, the scheduled entity receives a second CSI-RS from the scheduling entity. In one aspect, the communication and processing circuitry 1440 can provide a means to receive the second CSI-RS. In one example, the second CSI-RS may be the CSI-RS 603 of FIG. 6. In one aspect, the channel state feedback circuitry 1442 can provide a means to estimate the wireless channel between the scheduling entity and the scheduled entity using the second CSI-RS and generate a second CSI report to provide channel state feedback to the scheduling entity.

At block 1508, the scheduled entity can transmit a second CSI report based on the second CSI-RS and the first CSI report. The second CSI report can include one or more second CSI components derived at least in part from the one or more first CSI components. In one aspect, the communication and processing circuitry 1440 can provide a means to transmit the second CSI report. In one example, the second CSI report may be a delta CSI report (e.g., delta CSI report 604 of FIG. 6) . The second CSI report can include one or more second CSI components, for example, dCRI, dRI, dLI, dPMI, and dCQI, based on the second CSI-RS and at least in part on one or more first CSI components (e.g., CRI, RI, LI, PMI, CQI) . In one aspect, the channel state feedback circuitry 1442 can provide a means to determine the one or more second CSI components based on at least in part from the one or more first CSI components. For example, the scheduled entity can determine one or more of dCRI, dRI, dLI, dPMI, and dCQI based on a differential function on one or more of the first CSI components.

In one configuration, the apparatus 1400 for wireless communication includes means for performing the above described processes of FIG. 15. In one aspect, the aforementioned means may be the processor 1404 shown in FIG. 14 configured to perform the functions recited by the aforementioned means. In another aspect, the aforementioned means may be a circuit or any apparatus configured to perform the functions recited by the aforementioned means.

Of course, in the above examples, the circuitry included in the processor 1404 is merely provided as an example, and other means for carrying out the described functions may be included within various aspects of the present disclosure, including but not limited to the instructions stored in the computer-readable storage medium 1406, or any other suitable apparatus or means described in any one of the FIGs. 1, 2, and/or 6, and utilizing, for example, the processes and/or algorithms described herein in relation to FIG. 15.

In a first aspect, a method for wireless communications by a user equipment (UE) is provided. The method comprises: receiving a first channel state information reference signal (CSI-RS) from a scheduling entity; transmitting a first CSI report based on the first CSI-RS, the first CSI report comprising one or more first CSI components; receiving a second CSI-RS from the scheduling entity; and transmitting a second CSI report based on the second CSI-RS and the first CSI report, the second CSI report comprising one or more second CSI components derived at least in part from the one or more first CSI components.

In a second aspect, alone or in combination with the first aspect, wherein: the one or more first CSI components comprise one or more first channel quality information (CQI) values; and the one or more second CSI components comprise one or more second CQI values derived from the one or more first CQI values.

In a third aspect, alone or in combination with the second aspect, wherein the one or more second CQI values occupy a smaller bit-length than that of the one or more first CQI values.

In a fourth aspect, alone or in combination with any of the second to third aspects, the method further comprises: deriving the one or more second CQI values based on a difference between the one or more first CQI values and the one or more second CQI values.

In a fifth aspect, alone or in combination with any of the first to fourth aspects, wherein: the one or more first CSI components comprise a first precoding matrix indicator (PMI) based on the first CSI-RS; and the one or more second CSI components comprise a second PMI based on the second CSI-RS and the first PMI.

In a sixth aspect, alone or in combination with the fifth aspect, wherein at least one coefficient of the second PMI is derived from one or more coefficients of the first PMI using a differential function.

In a seventh aspect, alone or in combination with any of the fifth to sixth aspects, wherein the first PMI and the second PMI have different periodicities with respect to one or more coefficients respectively included in the first PMI and the second PMI.

In an eighth aspect, alone or in combination with any of the first to seventh aspects, wherein: the first CSI report comprises channel quality information (CQI) , precoding matrix indicator (PMI) , CSI-RS resource indicator (CRI) , layer indicator (LI) , and rank indicator (RI) ; and the second CSI report comprises differential CQI (dCQI) , differential PMI (dPMI) , differential CRI (dCRI) , differential LI (dLI) , and differential RI (dRI) ; the method further comprises transmitting uplink control information (UCI) comprising: dCRI, dRI, dLI, zero padding, dPMI, and dCQI arranged in sequence in the UCI; or CRI, dCRI, RI, dRI, LI, dLI, zero padding, PMI, dPMI, CQI, and dCQI arranged in sequence in the UCI.

In a ninth aspect, a method for wireless communications by a scheduling entity is provided. The method comprises: transmitting a first channel state information reference signal (CSI-RS) to a user equipment (UE) ; receiving, from the UE, a first CSI report based on the first CSI-RS, the first CSI report comprising one or more first CSI components; transmitting a second CSI-RS to the UE; and receiving, from the UE, a second CSI report based on the second CSI-RS and the first CSI report, the second CSI report comprising one or more second CSI components derived at least in part from the one or more first CSI components.

In a tenth aspect, alone or in combination with the ninth aspect, wherein: the one or more first CSI components comprise one or more first channel quality information (CQI) values; and the one or more second CSI components comprise one or more second CQI values derived from the one or more first CQI values.

In an eleventh aspect, alone or in combination with the tenth aspect, wherein the one or more second CQI values occupy a smaller bit-length than that of the one or more first CQI values.

In a twelfth aspect, alone or in combination with any of the tenth to eleventh aspects, the method further comprises: deriving the one or more second CQI values based on a difference between the one or more first CQI values and the one or more second CQI values.

In a thirteenth aspect, alone or in combination with any of the ninth to twelfth aspects, wherein: the one or more first CSI components comprise a first precoding matrix indicator (PMI) based on the first CSI-RS; and the one or more second CSI components comprise a second PMI based on the second CSI-RS and the first PMI.

In a fourteenth aspect, alone or in combination with the thirteenth aspect, wherein at least one coefficient of the second PMI is derived from one or more coefficients of the first PMI using a differential function.

In a fifteenth aspect, alone or in combination with any of the thirteenth to fourteenth aspects, wherein the first PMI and the second PMI have different periodicities with respect to one or more coefficients respectively included in the first PMI and the second PMI.

In a sixteenth aspect, a user equipment (UE) for wireless communication is provided. The UE includes a transceiver configured for wireless communication, a memory, and a processor coupled with the transceiver and the memory. Wherein the processor and the memory are configured to: receive a first channel state information reference signal (CSI-RS) from a scheduling entity; transmit a first CSI report based on the first CSI-RS, the first CSI report comprising one or more first CSI components; receive a second CSI-RS from the scheduling entity; and transmit a second CSI report based on the second CSI-RS and the first CSI report, the second CSI report comprising one or more second CSI components derived at least in part from the one or more first CSI components.

In a seventeenth aspect, alone or in combination with the sixteenth aspect, wherein: the one or more first CSI components comprise one or more first channel quality information (CQI) values; and the one or more second CSI components comprise one or more second CQI values derived from the one or more first CQI values.

In an eighteenth aspect, alone or in combination with the seventeenth aspect, wherein the one or more second CQI values occupy a smaller bit-length than that of the one or more first CQI values.

In a nineteenth aspect, alone or in combination with any of the seventeenth to eighteenth aspects, wherein the processor and the memory are further configured to: derive the one or more second CQI values based on a difference between the one or more first CQI values and the one or more second CQI values.

In a twentieth aspect, alone or in combination with any of the sixteenth to nineteenth aspects, wherein: the one or more first CSI components comprise a first precoding matrix indicator (PMI) based on the first CSI-RS; and the one or more second CSI components comprise a second PMI based on the second CSI-RS and the first PMI.

In a twenty-first aspect, alone or in combination with the twentieth aspect, wherein at least one coefficient of the second PMI is derived from one or more coefficients of the first PMI using a differential function.

In a twenty-second aspect, alone or in combination with any of the twentieth to twenty-first aspects, wherein the first PMI and the second PMI have different periodicities with respect to one or more coefficients respectively included in the first PMI and the second PMI.

In a twenty-third aspect, alone or in combination with any of the sixteenth to twenty-second aspects, wherein: the first CSI report comprises channel quality information (CQI) , precoding matrix indicator (PMI) , CSI-RS resource indicator (CRI) , layer indicator (LI) , and rank indicator (RI) ; and the second CSI report comprises differential CQI (dCQI) , differential PMI (dPMI) , differential CRI (dCRI) , differential LI (dLI) , and differential RI (dRI) ; the processor and the memory are further configured to transmit uplink control information (UCI) comprising: dCRI, dRI, dLI, zero padding, dPMI, and dCQI arranged in sequence in the UCI; or CRI, dCRI, RI, dRI, LI, dLI, zero padding, PMI, dPMI, CQI, and dCQI arranged in sequence in the UCI.

In a twenty-fourth aspect, a scheduling entity for wireless communication is provided. The scheduling entity comprises a transceiver configured for wireless communication, a memory, and a processor coupled with the transceiver and the memory. Wherein the processor and the memory are configured to: transmit a first channel state information reference signal (CSI-RS) to a user equipment (UE) ; receive, from the UE, a first CSI report based on the first CSI-RS, the first CSI report comprising one or more first CSI components; transmit a second CSI-RS to the UE; and receive, from the UE, a second CSI report based on the second CSI-RS and the first CSI report, the second CSI report comprising one or more second CSI components derived at least in part from the one or more first CSI components.

In a twenty-fifth aspect, alone or in combination with the twenty-fourth aspect, wherein: the one or more first CSI components comprise one or more first channel quality information (CQI) values; and the one or more second CSI components comprise one or more second CQI values derived from the one or more first CQI values.

In a twenty-sixth aspect, alone or in combination with the twenty-fifth aspect, wherein the one or more second CQI values occupy a smaller bit-length than that of the one or more first CQI values.

In a twenty-seventh aspect, alone or in combination with any of the twenty-fifth to twenty-sixth aspects, wherein the processor and the memory are further configured to:derive the one or more second CQI values based on a difference between the one or more first CQI values and the one or more second CQI values.

In a twenty-eighth aspect, alone or in combination with any of the twenty-fourth to twenty-seventh aspects, wherein: the one or more first CSI components comprise a first precoding matrix indicator (PMI) based on the first CSI-RS; and the one or more second CSI components comprise a second PMI based on the second CSI-RS and the first PMI.

In a twenty-ninth aspect, alone or in combination with the twenty-eighth aspect, wherein at least one coefficient of the second PMI is derived from one or more coefficients of the first PMI using a differential function.

In a thirtieth aspect, alone or in combination with any of the twenty-eighth to twenty-ninth aspects, wherein the first PMI and the second PMI have different periodicities with respect to one or more coefficients respectively included in the first PMI and the second PMI.

Several aspects of a wireless communication network have been presented with reference to an exemplary implementation. As those skilled in the art will readily appreciate, various aspects described throughout this disclosure may be extended to other telecommunication systems, network architectures and communication standards.

By way of example, various aspects may be implemented within other systems defined by 3GPP, such as Long-Term Evolution (LTE) , the Evolved Packet System (EPS) , the Universal Mobile Telecommunication System (UMTS) , and/or the Global System for Mobile (GSM) . Various aspects may also be extended to systems defined by the 3rd Generation Partnership Project 2 (3GPP2) , such as CDMA2000 and/or Evolution-Data Optimized (EV-DO) . Other examples may be implemented within systems employing IEEE 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Ultra-Wideband (UWB) , Bluetooth, and/or other suitable systems. The actual telecommunication standard, network architecture, and/or communication standard employed will depend on the specific application and the overall design constraints imposed on the system.

Within the present disclosure, the word “exemplary” is used to mean “serving as an example, instance, or illustration. ” Any implementation or aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects of the disclosure. Likewise, the term “aspects” does not require that all aspects of the disclosure include the discussed feature, advantage or mode of operation. The term “coupled” is used herein to refer to the direct or indirect coupling between two objects. For example, if object A physically touches object B, and object B touches object C, then objects A and C may still be considered coupled to one another-even if they do not directly physically touch each other. For instance, a first object may be coupled to a second object even though the first object is never directly physically in contact with the second object. The terms “circuit” and “circuitry” are used broadly, and intended to include both hardware implementations of electrical devices and conductors that, when connected and configured, enable the performance of the functions described in the present disclosure, without limitation as to the type of electronic circuits, as well as software implementations of information and instructions that, when executed by a processor, enable the performance of the functions described in the present disclosure.

One or more of the components, steps, features and/or functions illustrated in FIGs. 1–15 may be rearranged and/or combined into a single component, step, feature or function or embodied in several components, steps, or functions. Additional elements, components, steps, and/or functions may also be added without departing from novel features disclosed herein. The apparatus, devices, and/or components illustrated in FIGs. 1–15 may be configured to perform one or more of the methods, features, or steps described herein. The novel algorithms described herein may also be efficiently implemented in software and/or embedded in hardware.

It is to be understood that the specific order or hierarchy of steps in the methods disclosed is an illustration of exemplary processes. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the methods may be rearranged. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented unless specifically recited therein.

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 are 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. 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 and b; a and c; b and c; and a, b and c. 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. ”

Claims

A method for wireless communications by a user equipment (UE) , comprising:

receiving a first channel state information reference signal (CSI-RS) from a scheduling entity;

transmitting a first CSI report based on the first CSI-RS, the first CSI report comprising one or more first CSI components;

receiving a second CSI-RS from the scheduling entity; and

transmitting a second CSI report based on the second CSI-RS and the first CSI report, the second CSI report comprising one or more second CSI components derived at least in part from the one or more first CSI components.
The method of claim 1, wherein:

the one or more first CSI components comprise one or more first channel quality information (CQI) values; and

the one or more second CSI components comprise one or more second CQI values derived from the one or more first CQI values.
The method of claim 2, wherein the one or more second CQI values occupy a smaller bit-length than that of the one or more first CQI values.
The method of claim 3, further comprising:

deriving the one or more second CQI values based on a difference between the one or more first CQI values and the one or more second CQI values.
The method of claim 1, wherein:

the one or more first CSI components comprise a first precoding matrix indicator (PMI) based on the first CSI-RS; and

the one or more second CSI components comprise a second PMI based on the second CSI-RS and the first PMI.
The method of claim 5, wherein at least one coefficient of the second PMI is derived from one or more coefficients of the first PMI using a differential function.
The method of claim 5, wherein the first PMI and the second PMI have different periodicities with respect to one or more coefficients respectively included in the first PMI and the second PMI.
The method of claim 1, wherein:

the first CSI report comprises channel quality information (CQI) , precoding matrix indicator (PMI) , CSI-RS resource indicator (CRI) , layer indicator (LI) , and rank indicator (RI) ; and

the second CSI report comprises differential CQI (dCQI) , differential PMI (dPMI) , differential CRI (dCRI) , differential LI (dLI) , and differential RI (dRI) ;

the method further comprising transmitting uplink control information (UCI) comprising:

dCRI, dRI, dLI, zero padding, dPMI, and dCQI arranged in sequence in the UCI; or

CRI, dCRI, RI, dRI, LI, dLI, zero padding, PMI, dPMI, CQI, and dCQI arranged in sequence in the UCI.
A method for wireless communications by a scheduling entity, comprising:

transmitting a first channel state information reference signal (CSI-RS) to a user equipment (UE) ;

receiving, from the UE, a first CSI report based on the first CSI-RS, the first CSI report comprising one or more first CSI components;

transmitting a second CSI-RS to the UE; and

receiving, from the UE, a second CSI report based on the second CSI-RS and the first CSI report, the second CSI report comprising one or more second CSI components derived at least in part from the one or more first CSI components.
The method of claim 9, wherein:

the one or more first CSI components comprise one or more first channel quality information (CQI) values; and

the one or more second CSI components comprise one or more second CQI values derived from the one or more first CQI values.
The method of claim 10, wherein the one or more second CQI values occupy a smaller bit-length than that of the one or more first CQI values.
The method of claim 11, further comprising:

deriving the one or more second CQI values based on a difference between the one or more first CQI values and the one or more second CQI values.
The method of claim 9, wherein:

the one or more first CSI components comprise a first precoding matrix indicator (PMI) based on the first CSI-RS; and

the one or more second CSI components comprise a second PMI based on the second CSI-RS and the first PMI.
The method of claim 13, wherein at least one coefficient of the second PMI is derived from one or more coefficients of the first PMI using a differential function.
The method of claim 13, wherein the first PMI and the second PMI have different periodicities with respect to one or more coefficients respectively included in the first PMI and the second PMI.
A user equipment (UE) for wireless communication, comprising:

a transceiver configured for wireless communication;

a memory; and

a processor coupled with the transceiver and the memory, wherein the processor and the memory are configured to:

receive a first channel state information reference signal (CSI-RS) from a scheduling entity;

transmit a first CSI report based on the first CSI-RS, the first CSI report comprising one or more first CSI components;

receive a second CSI-RS from the scheduling entity; and

transmit a second CSI report based on the second CSI-RS and the first CSI report, the second CSI report comprising one or more second CSI components derived at least in part from the one or more first CSI components.
The UE of claim 16, wherein:

the one or more first CSI components comprise one or more first channel quality information (CQI) values; and

the one or more second CSI components comprise one or more second CQI values derived from the one or more first CQI values.
The UE of claim 17, wherein the one or more second CQI values occupy a smaller bit-length than that of the one or more first CQI values.
The UE of claim 18, wherein the processor and the memory are further configured to:

derive the one or more second CQI values based on a difference between the one or more first CQI values and the one or more second CQI values.
The UE of claim 16, wherein:

the one or more first CSI components comprise a first precoding matrix indicator (PMI) based on the first CSI-RS; and

the one or more second CSI components comprise a second PMI based on the second CSI-RS and the first PMI.
The UE of claim 20, wherein at least one coefficient of the second PMI is derived from one or more coefficients of the first PMI using a differential function.
The UE of claim 20, wherein the first PMI and the second PMI have different periodicities with respect to one or more coefficients respectively included in the first PMI and the second PMI.
The UE of claim 16, wherein:

the first CSI report comprises channel quality information (CQI) , precoding matrix indicator (PMI) , CSI-RS resource indicator (CRI) , layer indicator (LI) , and rank indicator (RI) ; and

the second CSI report comprises differential CQI (dCQI) , differential PMI (dPMI) , differential CRI (dCRI) , differential LI (dLI) , and differential RI (dRI) ;

the processor and the memory are further configured to transmit uplink control information (UCI) comprising:

dCRI, dRI, dLI, zero padding, dPMI, and dCQI arranged in sequence in the UCI; or

CRI, dCRI, RI, dRI, LI, dLI, zero padding, PMI, dPMI, CQI, and dCQI arranged in sequence in the UCI.
A scheduling entity for wireless communication, comprising:

a transceiver configured for wireless communication;

a memory; and

a processor coupled with the transceiver and the memory, wherein the processor and the memory are configured to:

transmit a first channel state information reference signal (CSI-RS) to a user equipment (UE) ;

receive, from the UE, a first CSI report based on the first CSI-RS, the first CSI report comprising one or more first CSI components;

transmit a second CSI-RS to the UE; and

receive, from the UE, a second CSI report based on the second CSI-RS and the first CSI report, the second CSI report comprising one or more second CSI components derived at least in part from the one or more first CSI components.
The scheduling entity of claim 24, wherein:

the one or more first CSI components comprise one or more first channel quality information (CQI) values; and

the one or more second CSI components comprise one or more second CQI values derived from the one or more first CQI values.
The scheduling entity of claim 25, wherein the one or more second CQI values occupy a smaller bit-length than that of the one or more first CQI values.
The scheduling entity of claim 26, wherein the processor and the memory are further configured to:

derive the one or more second CQI values based on a difference between the one or more first CQI values and the one or more second CQI values.
The scheduling entity of claim 24, wherein:

the one or more first CSI components comprise a first precoding matrix indicator (PMI) based on the first CSI-RS; and

the one or more second CSI components comprise a second PMI based on the second CSI-RS and the first PMI.
The scheduling entity of claim 28, wherein at least one coefficient of the second PMI is derived from one or more coefficients of the first PMI using a differential function.
The scheduling entity of claim 28, wherein the first PMI and the second PMI have different periodicities with respect to one or more coefficients respectively included in the first PMI and the second PMI.