QCL Type D Sounding Reference Signal

Abstract

Methods, systems, and apparatus for wireless communications are described. In general, the described techniques provide a transmission configuration indication state that indicates a quasi-co-location relationship. For example, a user equipment (UE) may transmit an uplink reference signal to a base station and, in response, receive a transmission configuration indication state based on the uplink reference signal from the base station. In some examples, the transmission configuration indication state may indicate a quasi-co-location relationship between the uplink reference signal and one or more reference signals associated with a downlink channel. In some implementations, the quasi-co-location relationship may be a spatial relationship between one or more antenna ports associated with the base station for receiving the uplink reference signal and one or more antenna ports for transmitting downlink data. The UE may receive downlink data based on the transmission configuration indication state and the indicated quasi-co-location relationship.

Description

[0001] Cross-references

[0002] This patent application claims priority to U.S. patent application No. 17 / 090,490, filed by BAI et al. on November 5, 2020, entitled “QCL-TYPE-D SOUNDING REFERENCE SIGNAL,” and U.S. provisional patent application No. 62 / 951,994, filed by BAI et al. on December 20, 2019, entitled “QCL-TYPE-D SOUNDING REFERENCE SIGNAL,” each of which is assigned to the assignee of this application.

[0003] public domain

[0004] The present disclosure relates generally to wireless communications, and more particularly to a transmission configuration indication (TCI) state indicating a quasi co-location (QCL) relationship.

[0005] Related technical description

[0006] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, broadcast, and the like. These systems may be capable of supporting communication with multiple users by sharing available system resources, such as time, frequency, and power. Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, and orthogonal frequency division multiple access (OFDMA) systems (such as long-term evolution (LTE) systems or fifth-generation (5G) new radio (NR) systems). A wireless multiple-access communication system may include several base stations or access network nodes, each of which simultaneously supports communication for multiple communication devices, which may also be referred to as user equipment (UE).

[0007] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at a city, country, region, and even global level. An example telecommunication standard is 5G New Radio (NR), which is part of the continued mobile broadband evolution promulgated by the Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability, and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and ultra-reliable low latency communications (URLLC). Improvements in 5G NR technology may also be applicable to other multiple access technologies and the telecommunication standards that employ them.

[0008] Overview

[0009] The systems, methods, and devices of the present disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein.

[0010] One innovative aspect of the subject matter described in the present disclosure may be implemented as a method for wireless communication. The method may be performed by a user equipment (UE) and may include transmitting an uplink (UL) reference signal to a base station; receiving a transmission configuration indication (TCI) state from the base station based at least in part on the UL reference signal; and receiving DL data from the base station on a downlink (DL) channel based at least in part on the TCI state. The TCI state may be received in a downlink control information (DCI) message and may indicate a quasi-co-location (QCL) relationship between the UL reference signal and one or more reference signals of the DL channel. The QCL relationship may be a spatial relationship between one or more first antenna ports for receiving the UL reference signal and one or more second antenna ports for transmitting the DL data. In some aspects, the UL reference signal may be a sounding reference signal (SRS), the DL channel may be a physical downlink shared channel (PDSCH), and the one or more reference signals may include a demodulation reference signal (DM-RS) for the PDSCH.

[0011] The TCI state may also indicate a QCL relationship between a channel state information reference signal (CSI-RS) and one or more reference signals of a DL channel. In some aspects, the QCL relationship between the UL reference signal and the one or more reference signals of the DL channel includes a QCL type D relationship, and the QCL relationship between the CSI-RS and the one or more reference signals of the DL channel may be one of a QCL type A relationship, a QCL type B relationship, or a QCL type C relationship.

[0012] In some implementations, the method may further include receiving a CSI-RS from a base station; determining a plurality of channel estimation parameters based on the CSI-RS; and decoding the DL data based at least in part on the plurality of channel estimation parameters determined from the CSI-RS. The channel estimation parameters may include one or more of a Doppler shift, a Doppler spread, an average delay, or an average spread determined for the CSI-RS. Additionally or alternatively, the method may include concurrently modifying the UL beam configuration and the DL beam configuration based on the TCI state.

[0013] Another innovative aspect of the subject matter described in the present disclosure can be implemented in an apparatus for wireless communication, such as a user equipment (UE). The UE may include one or more processors coupled to a memory. The memory may store instructions that, when executed by the one or more processors, cause the UE to perform operations including: transmitting an uplink (UL) reference signal to a base station; receiving a TCI state based at least in part on the UL reference signal from the base station; and receiving DL data from the base station on a downlink (DL) channel based on the TCI state. The TCI state may be received in a downlink control information (DCI) message and may indicate a QCL relationship between the UL reference signal and one or more reference signals of the DL channel. The QCL relationship may be a spatial relationship between one or more first antenna ports for receiving the UL reference signal and one or more second antenna ports for transmitting the DL data. In some aspects, the UL reference signal may be a sounding reference signal (SRS), the DL channel may be a physical downlink shared channel (PDSCH), and the one or more reference signals may include a demodulation reference signal (DM-RS) for the PDSCH.

[0014] The TCI state may also indicate a QCL relationship between a channel state information reference signal (CSI-RS) and one or more reference signals of a DL channel. In some aspects, the QCL relationship between the UL reference signal and the one or more reference signals of the DL channel may be a QCL type D relationship, and the QCL relationship between the CSI-RS and the one or more reference signals of the DL channel may be one of a QCL type A relationship, a QCL type B relationship, or a QCL type C relationship.

[0015] In some implementations, execution of these instructions may cause the UE to perform operations further including: receiving a CSI-RS from a base station; determining a number of channel estimation parameters based at least in part on the CSI-RS; and decoding DL data based at least in part on the number of channel estimation parameters determined from the CSI-RS. The channel estimation parameters may include one or more of a Doppler shift, a Doppler spread, an average delay, or an average spread determined for the CSI-RS. Additionally or alternatively, execution of these instructions may cause the UE to perform operations further including: concurrently modifying an UL beam configuration and a DL beam configuration based on a TCI state.

[0016] Another innovative aspect of the subject matter described in the present disclosure can be implemented as a method for wireless communication. The method can be performed by a base station and can include receiving an uplink reference signal from a UE; configuring a set of TCI states, the set of TCI states including at least one TCI state based at least in part on a received uplink (UL) reference signal; and scheduling a physical downlink shared channel (PDSCH) based at least in part on at least one TCI state associated with the received UL reference signal. In some implementations, the method can also include transmitting at least one TCI state associated with the received UL reference signal to the UE; and transmitting DL data to the UE on a scheduled PDSCH based at least in part on the at least one TCI state. The TCI state can be transmitted to the UE in a DCI message and can indicate a QCL relationship between the UL reference signal and one or more reference signals of the PDSCH. The QCL relationship can be a spatial relationship between one or more first antenna ports for receiving the UL reference signal and one or more second antenna ports for transmitting the DL data. In some aspects, the UL reference signal can be a sounding reference signal (SRS), and the one or more reference signals can include a demodulation reference signal (DM-RS) for the PDSCH.

[0017] The TCI state may also indicate a QCL relationship between a channel state information reference signal (CSI-RS) and one or more reference signals of the PDSCH. In some aspects, the QCL relationship between the UL reference signal and the one or more reference signals of the PDSCH may be a QCL type D relationship, and the QCL relationship between the CSI-RS and the one or more reference signals of the PDSCH may be one of a QCL type A relationship, a QCL type B relationship, or a QCL type C relationship.

[0018] In some other implementations, the method may further include determining a plurality of channel estimation parameters based on an UL reference signal; and configuring at least one TCI state based at least in part on the plurality of channel estimation parameters determined from the UL reference signal. The channel estimation parameters may include one or more of a Doppler shift, a Doppler spread, an average delay, or an average spread determined for a CSI-RS. Additionally or alternatively, the method may include concurrently modifying an UL beam configuration and a DL beam configuration based on the at least one TCI state.

[0019] Another innovative aspect of the subject matter described in the present disclosure can be implemented in an apparatus for wireless communication, such as a base station. The base station may include one or more processors coupled to a memory. The memory may store instructions that, when executed by the one or more processors, cause a UE to perform operations comprising: receiving an uplink reference signal from the UE; configuring a set of TCI states, the set of TCI states including at least one TCI state based at least in part on a received uplink (UL) reference signal; and scheduling a physical downlink shared channel (PDSCH) based at least in part on at least one TCI state associated with the received UL reference signal. In some implementations, execution of the instructions may cause the base station to perform operations further comprising: transmitting at least one TCI state associated with the set of UL reference signals to the UE; and transmitting DL data to the UE on a scheduled PDSCH based at least in part on the at least one TCI state. The TCI state may be transmitted to the UE in a DCI message and may indicate a QCL relationship between the UL reference signal and one or more reference signals of the PDSCH. The QCL relationship may be a spatial relationship between one or more first antenna ports used to receive the UL reference signal and one or more second antenna ports used to transmit the DL data. In some aspects, the UL reference signal may be a sounding reference signal (SRS), and the one or more reference signals may include a demodulation reference signal (DM-RS) for the PDSCH.

[0020] The TCI state may also indicate a QCL relationship between a channel state information reference signal (CSI-RS) and one or more reference signals of the PDSCH. In some aspects, the QCL relationship between the UL reference signal and the one or more reference signals of the PDSCH may be a QCL type D relationship, and the QCL relationship between the CSI-RS and the one or more reference signals of the PDSCH may be one of a QCL type A relationship, a QCL type B relationship, or a QCL type C relationship.

[0021] In some other implementations, execution of these instructions may cause the base station to perform operations further comprising: determining a plurality of channel estimation parameters based at least in part on an UL reference signal; and configuring at least one TCI state based at least in part on the plurality of channel estimation parameters determined from the UL reference signal. The channel estimation parameters may include one or more of a Doppler shift, a Doppler spread, an average delay, or an average spread determined for a CSI-RS. Additionally or alternatively, the method may include concurrently modifying an UL beam configuration and a DL beam configuration based on the at least one TCI state.

[0022] Details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the following description. Other features, aspects, and advantages will become apparent from the description, drawings, and claims. It should be noted that the relative dimensions of the following drawings may not be drawn to scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A diagram illustrating an example wireless communication system and access network is shown.

[0025] Figure 2A An example of a first fifth generation (5G) or new radio (NR) frame is shown.

[0026] Figure 2B Example downlink channels within a 5G / NR timeslot are shown.

[0027] Figure 2C An example of a second 5G / NR frame is shown.

[0028] Figure 2D Example uplink channels within a 5G / NR timeslot are shown.

[0029] Figure 3 A diagram illustrating example base stations and user equipment (UE) in an access network is shown.

[0030] Figure 4 An example wireless communication system supporting bidirectional transmission of configuration indication status is illustrated.

[0031] Figure 5 A sequence diagram for wireless communication between a base station and a UE is shown.

[0032] Figure 6 A flow diagram depicting example operations for wireless communications between a base station and a UE is shown.

[0033] Figure 7A and 7B A flow diagram depicting example operations for wireless communications between a base station and a UE is shown.

[0034] Figure 8 A flow diagram depicting example operations for wireless communications between a base station and a UE is shown.

[0035] Figure 9A 、 9B 9C show flow charts depicting example operations for wireless communications between a base station and a UE.

[0036] Like reference numbers and designations in the various drawings indicate like elements.

[0037] Detailed description

[0038] The following description is directed to some implementations to describe the innovative aspects of the present disclosure. However, one of ordinary skill in the art will readily recognize that the teachings herein can be applied in many different ways. The described implementations can be implemented in any device, system, or network capable of transmitting and receiving radio frequency (RF) signals according to one or more of the following: Long Term Evolution (LTE), third generation (3G), fourth generation (4G), or fifth generation (5G) (New Radio (NR)) standards promulgated by the Third Generation Partnership Project (3GPP), the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, the IEEE 802.15 standard, or as defined by the Bluetooth Special Interest Group (SIG). Standards, etc. The described implementations can be implemented in any device, system, or network capable of transmitting and receiving RF signals according to one or more of the following technologies or techniques: code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single carrier FDMA (SC-FDMA), single user (SU) multiple input multiple output (MIMO), and multi-user (MU) MIMO. The described implementations can also be implemented using other wireless communication protocols or RF signals suitable for use in one or more of a wireless wide area network (WWAN), a wireless personal area network (WPAN), a wireless local area network (WLAN), or an Internet of Things (IoT) network.

[0039] Several aspects of telecommunications systems will now be presented with reference to various apparatus and methods. These apparatus and methods are described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively, "elements"). These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends on the application and the design constraints imposed on the overall system.

[0040] As an example, an element, or any part of an element, or any combination of elements can be implemented as a "processing system" comprising one or more processors. Examples of processors include: a microprocessor, a microcontroller, a graphics processing unit (GPU), a central processing unit (CPU), an application processor, a digital signal processor (DSP), a reduced instruction set computing (RISC) processor, a system on a chip (SoC), a baseband processor, a field programmable gate array (FPGA), a programmable logic device (PLD), a state machine, a gating logic, a discrete hardware circuit, and other suitable hardware configured to perform the various functionalities described throughout this disclosure. One or more processors in a processing system can execute software. Software should be broadly interpreted to mean instructions, instruction sets, codes, code segments, program codes, programs, subroutines, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether it is described in software, firmware, middleware, microcode, hardware description language, or other terms.

[0041] Accordingly, in one or more example implementations, the functions described can be implemented in hardware, software, or any combination thereof. If implemented in software, each function can be stored or encoded as one or more instructions or codes on a computer-readable medium. Computer-readable media include computer storage media. The storage medium can be any available medium that can be accessed by a computer. By way of example and not limitation, such computer-readable media may include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, a combination of the above-mentioned types of computer-readable media, or any other medium that can be used to store computer-accessible instructions or data structures in the form of computer-executable code.

[0042] Figure 1 A diagram of an example wireless communication system and access network 100 according to various aspects of the present disclosure is shown. The wireless communication system (also known as a wireless wide area network (WWAN)) includes a base station 102, a UE 104, an evolved packet core (EPC) 160, and another core network 190 (such as a 5G core (5GC)). The base station 102 may include a macro cell (a high-power cellular base station) or a small cell (a low-power cellular base station). A macro cell includes a base station. Small cells include femto cells, pico cells, and micro cells.

[0043] Base stations 102 configured for 4G LTE (collectively referred to as the Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) can interface with the EPC 160 via a backhaul link 132, such as an S1 interface. Base stations 102 configured for 5G NR (collectively referred to as the Next Generation RAN (NG-RAN)) can interface with the core network 190 via a backhaul link 184. Among other functions, the base stations 102 can perform one or more of the following functions: delivery of user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (such as handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, distribution of non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment tracking, RAN information management (RIM), paging, positioning, and delivery of alert messages. Base stations 102 may communicate with each other over a backhaul link 134, such as an X2 interface, directly or indirectly, such as through EPC 160 or core network 190. Backhaul link 134 may be wired or wireless.

[0044] Base stations 102 can communicate wirelessly with UEs 104. Each base station 102 can provide communication coverage for a respective geographic coverage area 110. There may be overlapping geographic coverage areas 110. For example, a small cell 102′ can have a coverage area 110′ that overlaps with the coverage area 110 of one or more macro base stations 102. A network that includes both small cells and macro cells can be referred to as a heterogeneous network. A heterogeneous network can also include a home evolved Node B (eNB) (HeNB), which can provide service to a restricted group known as a closed subscriber group (CSG). The communication link 120 between the base station 102 and the UE 104 can include an uplink (UL) (also known as a reverse link) transmission from the UE 104 to the base station 102 or a downlink (DL) (also known as a forward link) transmission from the base station 102 to the UE 104. The communication link 120 can use multiple-input multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, or transmit diversity. These communication links can be over one or more carriers. For each carrier allocated in the carrier aggregation for up to Yx MHz (x component carriers) for transmission in each direction, the base station 102 / UE 104 can use spectrum with a bandwidth of up to Y MHz (such as 5 MHz, 10 MHz, 15 MHz, 20 MHz, 100 MHz, 400 MHz, etc.). These carriers may or may not be adjacent to each other. The allocation of carriers may be asymmetric with respect to DL and UL (such as more or fewer carriers may be allocated to DL compared to UL). Component carriers may include a primary component carrier and one or more secondary component carriers. The primary component carrier may be referred to as a primary cell (PCell), and the secondary component carrier may be referred to as a secondary cell (SCell).

[0045] Some UEs 104 may communicate with each other using device-to-device (D2D) communication links 158. The D2D communication links 158 may use DL / UL WWAN spectrum. The D2D communication links 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), and a physical sidelink control channel (PSCCH). D2D communication may be accomplished through various wireless D2D communication systems, such as, for example, FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the IEEE 802.11 standard, LTE, or NR.

[0046] The wireless communication system may further include a Wi-Fi access point (AP) 150 that communicates with a Wi-Fi station (STA) 152 in the 5 GHz unlicensed spectrum via a communication link 154. When communicating in the unlicensed spectrum, the STA 152 / AP 150 may perform a clear channel assessment (CCA) to determine whether the channel is available before communicating.

[0047] Small cell 102′ can operate in licensed or unlicensed spectrum. When operating in unlicensed spectrum, small cell 102′ can employ NR and use the same 5 GHz unlicensed spectrum used by Wi-Fi AP 150. Small cell 102′ employing NR in unlicensed spectrum can boost access network coverage or increase access network capacity.

[0048] Whether a small cell 102′ or a large cell (such as a macro base station), base station 102 may include an eNB, a gNode B (gNB), or another type of base station. Some base stations, such as gNB 180, may operate in the traditional sub-6 GHz spectrum, millimeter wave (mmW) frequencies, or near-mmW frequencies to communicate with UE 104. When gNB 180 operates in mmW or near-mmW frequencies, gNB 180 may be referred to as a mmW or mmW base station. Extremely high frequency (EHF) is a portion of the RF spectrum in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and a wavelength between 1 mm and 10 mm. Radio waves in this band may be referred to as millimeter waves. Near-mmW extends down to 3 GHz frequencies with a wavelength of 100 mm. Super high frequency (SHF) bands extend between 3 GHz and 30 GHz and are also referred to as centimeter waves. Communications using mmW / near-mmW radio frequency bands (such as between 3 GHz and 300 GHz) have extremely high path loss and short range. The mmW base station 180 may utilize beamforming 182 with the UE 104 to compensate for the extremely high path loss and short range.

[0049] Base station 180 may transmit beamformed signals in one or more transmit directions 182′ to UE 104. UE 104 may receive beamformed signals from base station 180 in one or more receive directions 182″. UE 104 may also transmit beamformed signals to base station 180 in one or more transmit directions. Base station 180 may receive beamformed signals from UE 104 in one or more receive directions. Base station 180 and UE 104 may perform beam training to determine the best receive direction and transmit direction for each of base station 180 and UE 104. The transmit direction and receive direction of base station 180 may be the same or different. The transmit direction and receive direction of UE 104 may be the same or different.

[0050] EPC 160 may include a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and a Packet Data Network (PDN) Gateway 172. MME 162 may be in communication with a Home Subscriber Server (HSS) 174. MME 162 is a control node that handles signaling between UE 104 and EPC 160. Generally speaking, MME 162 provides bearer and connection management. All user Internet Protocol (IP) packets are passed through Serving Gateway 166, which itself is connected to PDN Gateway 172. PDN Gateway 172 provides UE IP address allocation and other functions. PDN Gateway 172 and BM-SC 170 are connected to IP Services 176. IP Services 176 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), PS Streaming services, or other IP services. The BM-SC 170 provides functionality for provisioning and delivering MBMS user services. It serves as the entry point for content providers' MBMS transmissions, authorizes and initiates MBMS bearer services within the Public Land Mobile Network (PLMN), and schedules MBMS transmissions. The MBMS Gateway 168 distributes MBMS traffic to base stations 102 within the Multicast Broadcast Single Frequency Network (MBSFN) area of ​​the broadcast service and is responsible for session management (start / stop) and collecting eMBMS-related charging information.

[0051] The core network 190 may include an access and mobility management function (AMF) 192, other AMFs 193, a session management function (SMF) 194, and a user plane function (UPF) 195. The AMF 192 may be in communication with a unified data management (UDM) 196. The AMF 192 is a control node that handles signaling between the UE 104 and the core network 190. Generally speaking, the AMF 192 provides QoS flow and session management. All user Internet Protocol (IP) packets are passed through the UPF 195. The UPF 195 provides UE IP address allocation and other functions. The UPF 195 is connected to the IP services 197. The IP services 197 may include the Internet, an intranet, an IP multimedia subsystem (IMS), PS streaming services, or other IP services.

[0052] A base station may also be referred to as a gNB, a NodeB, an evolved NodeB (eNB), an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), a transmit reception point (TRP), or some other suitable terminology. Base station 102 provides an access point for UE 104 to EPC 160 or core network 190. Examples of UE 104 include a cellular phone, a smartphone, a Session Initiation Protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (such as an MP3 player), a camera, a game console, a tablet device, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor / actuator, a display, or any other similarly functional device. Some UEs 104 may be referred to as IoT devices (such as parking meters, gas pumps, ovens, vehicles, heart monitors, etc.). UE 104 may also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communication device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.

[0053] Figure 2A An example of a first time slot 200 within a 5G / NR frame structure is shown in accordance with aspects of the present disclosure. Figure 2B An example of a DL channel 230 within a 5G / NR timeslot is shown in accordance with aspects of the present disclosure. Figure 2C An example of a second time slot 250 within a 5G / NR frame structure is shown in accordance with aspects of the present disclosure. Figure 2D An example of a UL channel 280 within a 5G / NR timeslot is shown in accordance with aspects of the present disclosure. In some cases, the 5G / NR frame structure may be frequency division duplex (FDD), where for a set of subcarriers (carrier system bandwidth), timeslots within the set of subcarriers are dedicated to either DL or UL transmissions. In other cases, the 5G / NR frame structure may be time division duplex (TDD), where for a set of subcarriers (carrier system bandwidth), timeslots within the set of subcarriers are dedicated to both DL and UL transmissions. Figure 2A and 2CIn the example shown in , the 5G / NR frame structure is based on TDD, where slot 4 is configured with slot format 28 (mostly DL), where D indicates DL, U indicates UL, and X indicates that the slot can be used flexibly between DL and UL, and slot 3 is configured with slot format 34 (mostly UL). Although slots 3 and 4 are shown as having slot formats 34 and 28, respectively, any slot can be configured with any of the various available slot formats 0-61. Slot formats 0 and 1 are full DL and full UL, respectively. Other slot formats 2-61 include a mix of DL, UL, and flexible symbols. The UE can be configured to have a slot format (dynamically configured through downlink control information (DCI) or semi-statically configured through radio resource control (RRC) signaling) via a slot format indicator (SFI). The configured slot format can also be applied to a 5G / NR frame structure based on FDD.

[0054] Other wireless communication technologies may have different frame structures or different channels. A frame may be divided into several equally sized subframes. For example, a frame with a duration of 10 milliseconds (ms) may be divided into 10 equally sized subframes, each subframe having a duration of 1 ms. Each subframe may include one or more time slots. A subframe may also include mini-slots, which may include 7, 4, or 2 symbols. Each time slot may include 7 or 14 symbols, depending on the time slot configuration. For time slot configuration 0, each time slot may include 14 symbols, while for time slot configuration 1, each time slot may include 7 symbols. The symbols on the DL may be cyclic prefix (CP) OFDM (CP-OFDM) symbols. The symbols on the UL may be CP-OFDM symbols (such as for high throughput scenarios) or discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbols (also known as single carrier frequency division multiple access (SC-FDMA) symbols) (such as for power-limited scenarios).

[0055] The number of slots within a subframe is based on the slot configuration and parameter design. For slot configuration 0, different parameter designs (μ) 0 to 5 allow for 1, 2, 4, 8, 16, and 32 slots per subframe, respectively. For slot configuration 1, different parameter designs 0 to 2 allow for 2, 4, and 8 slots per subframe, respectively. Accordingly, for slot configuration 0 and parameter design μ, there are 14 symbols per slot and 2μ slots per subframe. The subcarrier spacing and symbol length / duration are a function of the parameter design. The subcarrier spacing can be equal to 2^μ*15kHz, where μ is parameter design 0 to 5. Thus, parameter design μ=0 has a subcarrier spacing of 15kHz, while parameter design μ=5 has a subcarrier spacing of 480kHz. The symbol length / duration is inversely related to the subcarrier spacing. Figures 2A-2DAn example is provided for slot configuration 0 with 14 symbols per slot and parameter design μ = 0 with 1 slot per subframe. The subcarrier spacing is 15 kHz and the symbol duration is approximately 66.7 microseconds (μs).

[0056] A resource grid can be used to represent the frame structure. Each slot consists of a resource block (RB) (also called a physical RB (PRB)) that spans 12 consecutive subcarriers and several symbols. The intersection of subcarriers spans 14 symbols. The intersection of subcarriers and RBs defines multiple resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

[0057] like Figure 2A As illustrated in , some REs carry reference signals (RS) for UEs. In some examples, one or more REs may carry a demodulation reference signal (DM-RS) (indicated as Rx for one example, where 100x is the port number, but other DM-RS configurations are possible). In some examples, one or more REs may carry a channel state information reference signal (CSI-RS) for channel measurement at the UE. REs may also include a beamforming reference signal (BRS), a beam refinement reference signal (BRRS), and a phase tracking reference signal (PT-RS).

[0058] Figure 2B Examples of various DL channels within a subframe of a frame are illustrated. The physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs), each CCE includes 9 RE groups (REGs), and each REG includes 4 consecutive REs in an OFDM symbol. The primary synchronization signal (PSS) can be within symbol 2 of a subframe of a frame. The PSS is used by the UE 104 to determine subframe or symbol timing and physical layer identity. The secondary synchronization signal (SSS) can be within symbol 4 of a subframe of a frame. The SSS is used by the UE to determine the physical layer cell identity group number and radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine the physical cell identifier (PCI). Based on the PCI, the UE can determine the position of the aforementioned DM-RS. The physical broadcast channel (PBCH) carrying the master information block (MIB) can be logically grouped with the PSS and SSS to form a synchronization signal (SS) / PBCH block. The MIB provides the number of RBs in the system bandwidth and the system frame number (SFN). The Physical Downlink Shared Channel (PDSCH) carries user data, broadcast system information not transmitted through the PBCH (such as System Information Blocks (SIBs)), and paging messages.

[0059] like Figure 2CAs illustrated in FIG, some REs carry DM-RSs (indicated as R for one example, but other DM-RS configurations are possible) used for channel estimation at the base station. The UE may transmit DM-RSs for the physical uplink control channel (PUCCH) and DM-RSs for the physical uplink shared channel (PUSCH). The PUSCH DM-RSs may be transmitted in the first one or the first two symbols of the PUSCH. The PUCCH DM-RSs may be transmitted in different configurations depending on whether a short PUCCH or a long PUCCH is transmitted and on the PUCCH format used. Although not shown, the UE may transmit a sounding reference signal (SRS). The SRS may be used by the base station for channel quality estimation to enable frequency-dependent scheduling on the UL.

[0060] Figure 2D Examples of various UL channels within a subframe of a frame are illustrated. The PUCCH may be positioned as indicated in one example. The PUCCH carries uplink control information (UCI), such as scheduling requests, channel quality indicators (CQI), precoding matrix indicators (PMI), rank indicators (RI), and hybrid automatic repeat request (HARQ) acknowledgement (ACK) / negative acknowledgement (NACK) feedback. The PUSCH carries data and may additionally be used to carry buffer status reports (BSRs), power headroom reports (PHRs), or UCI.

[0061] Figure 3A block diagram of an example of a base station 310 and a UE 350 in an access network according to various aspects of the present disclosure is shown. In the DL, IP packets from the EPC 160 may be provided to the controller / processor 375. The controller / processor 375 implements layer 3 and layer 2 functionality. Layer 3 includes the radio resource control (RRC) layer, and layer 2 includes the service data adaptation protocol (SDAP) layer, the packet data convergence protocol (PDCP) layer, the radio link control (RLC) layer, and the medium access control (MAC) layer. The controller / processor 375 provides RRC layer functionality associated with broadcasting of system information (such as MIBs and SIBs), RRC connection control (such as RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality associated with header compression / decompression, security (ciphering, deciphering, integrity protection, integrity verification), and handover support functions; RLC layer functionality associated with delivery of upper layer packet data units (PDUs), error correction through ARQ, concatenation, segmentation and reassembly of RLC service data units (SDUs), resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

[0062] The transmit (TX) processor 316 and receive (RX) processor 370 implement Layer 1 functionality associated with various signal processing functions. Layer 1, including the physical (PHY) layer, may include error detection on the transport channel, forward error correction (FEC) encoding / decoding of the transport channel, interleaving, rate matching, mapping onto the physical channel, modulation / demodulation of the physical channel, and MIMO antenna processing. The TX processor 316 handles the mapping to the signal constellation based on various modulation schemes, such as binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase shift keying (M-PSK), and M-quadrature amplitude modulation (M-QAM). The coded and modulated symbols may then be split into parallel streams. Each stream may then be mapped to an OFDM subcarrier, multiplexed with a reference signal (such as a pilot signal) in the time or frequency domain, and then combined using an inverse fast Fourier transform (IFFT) to produce a physical channel carrying a time-domain OFDM symbol stream. The OFDM stream is spatially precoded to produce multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine coding and modulation schemes, as well as for spatial processing. The channel estimates may be derived from a reference signal or channel condition feedback transmitted by the UE 350. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX may modulate an RF carrier with a corresponding spatial stream for transmission.

[0063] At the UE 350, each receiver 354RX receives a signal via its corresponding antenna 352. Each receiver 354RX recovers the information modulated onto the RF carrier and provides the information to a receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functionality associated with various signal processing functions. The RX processor 356 may perform spatial processing on the information to recover any spatial streams destined for the UE 350. If multiple spatial streams are destined for the UE 350, they may be combined by the RX processor 356 into a single OFDM symbol stream. The RX processor 356 then converts the OFDM symbol stream from the time domain to the frequency domain using a fast Fourier transform (FFT). The frequency domain signal includes a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, as well as the reference signal, are recovered and demodulated by determining the signal constellation point most likely transmitted by the base station 310. These soft decisions may be based on channel estimates calculated by the channel estimator 358. These soft decisions are then decoded and deinterleaved to recover the data and control signals originally transmitted on the physical channel by the base station 310. These data and control signals are then provided to the controller / processor 359, which implements layer 3 and layer 2 functionality.

[0064] The controller / processor 359 may be associated with a memory 360 that stores program codes and data. The memory 360 may be referred to as a computer-readable medium. In the UL, the controller / processor 359 provides demultiplexing between transport and logical channels, packet reassembly, cipher decoding, header decompression, and control signal processing to recover IP packets from the EPC 160. The controller / processor 359 is also responsible for error detection using an ACK or NACK protocol to support HARQ operations.

[0065] Similar to the functionality described in conjunction with DL transmissions performed by the base station 310, the controller / processor 359 provides RRC layer functionality associated with system information (such as MIB and SIB) acquisition, RRC connection, and measurement reporting; PDCP layer functionality associated with header compression / decompression and security (ciphering, deciphering, integrity protection, integrity verification); RLC layer functionality associated with delivery of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing MAC SDUs onto TBs, demultiplexing MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

[0066] Channel estimates derived by a channel estimator 358 from a reference signal or feedback transmitted by the base station 310 may be used by a TX processor 368 to select an appropriate coding and modulation scheme, and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antennas 352 via separate transmitters 354TX. Each transmitter 354TX may modulate an RF carrier with a corresponding spatial stream for transmission.

[0067] UL transmissions are processed at the base station 310 in a manner similar to that described in conjunction with the receiver functionality at the UE 350. Each receiver 318RX receives a signal through its respective antenna 320. Each receiver 318RX recovers information modulated onto an RF carrier and provides the information to an RX processor 370.

[0068] The controller / processor 375 may be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a computer-readable medium. In the UL, the controller / processor 375 provides demultiplexing between transport and logical channels, packet reassembly, cipher decoding, header decompression, and control signal processing to recover IP packets from the UE 350. The IP packets from the controller / processor 375 may be provided to the EPC 160. The controller / processor 375 is also responsible for error detection using an ACK or NACK protocol to support HARQ operations. Information to be communicated wirelessly (such as communications based on LTE or NR) is encoded at the PHY layer and mapped to one or more radio channels for transmission.

[0069] exist Figure 3 In the example shown in FIG3 , each antenna 352 of a UE 350 is coupled to a corresponding transmitter 354TX. However, in actual implementations, many UEs have fewer transmitters (or transmit chains) than receive (RX) antennas. Although not shown for simplicity, each transmitter can be coupled to a corresponding power amplifier (PA) that amplifies the signal to be transmitted. The combination of a transmitter and a PA may be referred to herein as a "transmit chain" or "TX chain." To save cost or die area, the same PA can be reused to transmit signals through multiple RX antennas. In other words, one or more TX chains of a UE can be switchably coupled to multiple RX antenna ports.

[0070] In some wireless communication systems, a base station may use multiple antennas to communicate with a UE. For one example, a base station may transmit parallel data streams to a UE using different antennas to increase throughput (rather than transmitting the data streams sequentially using the same antenna). For another example, a base station may use multiple antennas to transmit a given data stream to a UE to increase spatial diversity in the DL transmission. Transmitting data using multiple antennas may be based on antenna ports, which are logical entities that can map multiple data streams to multiple antennas. Each antenna port may be associated with a reference signal, for example, to enable a UE to distinguish between multiple data streams transmitted from different antennas of the base station.

[0071] Some antenna ports may be quasi-co-located relative to each other, for example, such that spatial parameters of a transmission on one antenna port can be inferred from spatial parameters of another transmission on another antenna port. A UE may be able to perform channel estimation based on reference signals received from a second set of antenna ports that are quasi-co-located with a first set of antenna ports for demodulating data or control information received from the first set of antenna ports. Thus, the QCL relationship between antenna ports may increase the UE's ability to receive and correctly decode DL transmissions from a base station.

[0072] The base station may configure a set of transmission configuration indication (TCI) states that indicate the QCL relationship between antenna ports used for DL ​​transmission to the UE. Each TCI state may be associated with a set of DL reference signals and may indicate the QCL relationship between antenna ports used to transmit the associated set of DL reference signals and antenna ports used to transmit DL data to the UE. When the UE receives an indication of the TCI state from the base station, the UE may determine that a first set of antenna ports used to transmit reference signals associated with the indicated TCI state is quasi-co-located with a second set of antenna ports used to transmit DL data to the UE. The QCL relationship between the first set of antenna ports and the second set of antenna ports may allow the UE to demodulate the DL data received from the base station using channel conditions or channel estimation parameters determined from the reference signals associated with the indicated TCI state. For example, if the TCI state indicates that the antenna port used to transmit the CSI-RS has a QCL relationship with the antenna port used to transmit the DL data, the UE may use channel information derived from the CSI-RS to demodulate or decode the DL data.

[0073] As mentioned above, the TCI state can be associated with or mapped to a DL reference signal transmitted by the base station, and can allow the base station to change the DL beam indication by modifying or updating the TCI state. For example, the TCI state can use a specific DL reference signal (such as one of SSB, CSI-RS, or TRP) as a reference signal resource and define the QCL relationship between the antenna port used to transmit the DL reference signal and the antenna port used for DL ​​transmission to the UE. The QCL relationship indicated in the TCI state can allow the UE to decode the DL transmission using the channel estimation parameters determined based on the DL reference signal. The base station can change the DL beam indication by using different TCI states that indicate the QCL relationship between the DL reference signal and the antenna port used to transmit DL data on different beams. Because some TCI states may not include or define a QCL relationship for the UL reference signal, some TCI states may not be able to change the UL beam indication, which may lead to asymmetry between DL beam management and UL beam management.

[0074] Various implementations of the subject matter disclosed herein may allow a base station to concurrently change DL beam indications and UL beam indications using a single TCI state by mapping the TCI state to a UL reference signal and defining at least one QCL relationship between the UL reference signal and the antenna port used for DL ​​transmissions to the UE. According to some aspects of the present disclosure, the UL reference signal may be used as a reference signal resource for the TCI state, and the TCI state may indicate the QCL relationship between the antenna port used to receive the UL reference signal and the antenna port used for DL ​​transmissions to the UE. In some aspects, a sounding reference signal (SRS) may be used as a reference signal resource for the TCI state, and the TCI state may indicate the QCL relationship between the antenna port used to receive the SRS and the antenna port used for DL ​​transmissions. In this way, the TCI state may be linked or mapped to the UL resource, which in turn may allow the base station to control or change the UL beam indication based on the TCI state indicated to the UE.

[0075] The QCL relationship indicated by the TCI state may not include channel estimation parameters that allow the UE to use channel information based on one or more associated reference signals to decode DL data. For example, while Type A, Type B, and Type C QCL relationships each indicate at least two channel estimation parameters that can be used by the UE to decode DL data transmitted from the base station, Type D QCL relationship indicates spatial RX parameters (rather than channel estimation parameters). In some implementations, if the TCI state indicates a Type D QCL relationship between the SRS and the antenna port used for DL ​​transmission, the base station (or appropriate network entity) may configure the TCI state to also indicate a QCL relationship between the DL reference signal and the antenna port used for DL ​​transmission, so that the UE can decode the DL data based at least in part on the channel conditions previously determined for the DL reference signal. In some aspects, a channel state information reference signal (CSI-RS) may be selected as a DL reference signal, and the corresponding QCL relationship may indicate one or more channel estimation parameters associated with the CSI-RS.

[0076] Therefore, various implementations of the subject matter disclosed herein can use a "bidirectional" TCI state that includes a first QCL relationship associated with an UL reference signal and also includes a second QCL relationship associated with a DL reference signal. The base station can use the bidirectional TCI state to concurrently control or change the DL beam indication and the UL beam indication. In this way, the base station can use a single TCI state to simultaneously change the DL beam indication and the UL beam indication, thereby unifying the DL beam indication and the UL beam indication.

[0077] Figure 4 An example wireless communication system 400 supporting bidirectional TCI states according to aspects of the present disclosure is shown. The wireless communication system 400 is shown to include Figure 1 Base station 102 and UE 104, and can achieve Figure 1 1 and 2. The present invention relates to various aspects of a wireless communication system 100 and access network. A base station 102, which can communicate with a UE 104 (and other UEs not shown for simplicity) within a coverage area 402 via one or more UL / DL links 404, can configure a set of TCI states corresponding to different QCL relationships between antenna ports for DL ​​transmissions to the UE 104. The set of configured TCI states can be provided to the UE 104 in an RRC configuration, in one or more DCI messages, or using some other suitable DL signaling. The base station 102 can also configure a number of bidirectional TCI states that can be used to concurrently control or change DL beam indications and UL beam indications.

[0078] In some other implementations, the base station 102 may generate updated TCI information that can be used to update or replace a TCI state (or a portion of a selected TCI state) based on any number of factors or conditions. For example, in some instances, the QCL relationship indicated by one or more of the configured TCI states may become outdated or invalid due to changing channel conditions. The base station 102 may update one or more TCI states (or one or more portions of a selected TCI state) by transmitting the updated TCI information to the UE 104, for example, in a DCI message 410. The UE 104 may receive the DCI message 410, extract the updated TCI state information contained therein, and update the locally stored TCI state based on the updated TCI state information provided by the base station 102.

[0079] The DCI message 410 may include a TCI state update field 420 for storing a number of updated TCI states (or portions thereof). The TCI state update field 420 is shown as including a TCI state index 422 and a reference signal index 424. The TCI state index 422 may identify the TCI state being updated, and the reference signal index 424 may identify an updated set of reference signals associated with each TCI state being updated. In some aspects, the TCI state index 422 may also identify an updated set of reference signals associated with the TCI state being updated.

[0080] Figure 5 A sequence diagram depicting communication 500 between a base station 502 and a UE 504 in a radio access network (RAN) according to various aspects of the present disclosure is shown. The base station 502 may be any suitable entity for communicating with one or more UEs, such as the UE 504, and may be a Node B, an enhanced / evolved NB (eNB), a 5G NB, a gNB, an access point (AP), or a transmit reception point (TRP). In some aspects, the base station 502 may be Figure 1 Base station 102 or Figure 3 An example of a base station 310, and the UE 504 may be Figure 1 UE 104 or Figure 3 An example of a UE 350.

[0081] The base station 502 configures a set of TCI states indicating a UL QCL relationship and a DL QCL relationship. As discussed above, the type D UL QCL relationship may indicate spatial RX parameters rather than channel estimation parameters and may allow the base station 502 to use channel estimation based on UL reference signals (such as SRS) to decode UL data received from the UE 504. The DL QCL relationship may allow the UE 504 to use channel estimation based on DL reference signals (such as CSI-RS) to decode DL data received from the base station 502. In some implementations, the TCI states indicating both the UL QCL relationship and the DL QCL relationship may be used to simultaneously control or change the UL beam indication and the DL beam indication. Figure 5 In the example of , the DL QCL relationship is associated with the CSI-RS transmitted from the base station 502, and the UL QCL relationship is associated with the SRS transmitted from the UE 504.

[0082] The base station 502 transmits a CSI-RS to the UE 504, and the UE 504 estimates channel conditions based on the CSI-RS. In some implementations, the UE 504 may measure one or more of Doppler shift, Doppler spread, average delay, or average spread based on the CSI-RS. The UE 504 transmits an SRS to the base station 502, and the base station 502 estimates channel conditions based on the SRS. In some implementations, the base station 502 may measure one or more of Doppler shift, Doppler spread, average delay, or average spread based on the SRS. The UE 504 may use the estimated channel conditions based on the CSI-RS to decode DL transmissions from the base station 502, and the base station 502 may use the estimated channel conditions based on the SRS to decode UL transmissions from the UE 504.

[0083] The base station 502 may determine that the UL beam and the DL beam are to be changed and may indicate the change to the UE 504 by transmitting an updated TCI state to the UE 504. The updated TCI state may include a new DL beam indication and a new UL beam indication.

[0084] Figure 6 A flow chart depicting example operations 600 for wireless communication between a base station and a UE in accordance with various aspects of the present disclosure is shown. Operations 600 may be performed by a wireless communication device such as Figure 1 UE 104, Figure 3 UE 350 or Figure 5 At block 602, the UE transmits an uplink (UL) reference signal to a base station. At block 604, the UE receives a TCI status based on the UL reference signal from the base station. At block 606, the UE receives DL data from the base station on a downlink (DL) channel based at least in part on the TCI status.

[0085] The TCI state may indicate a QCL relationship between a UL reference signal and one or more reference signals of a DL channel. The QCL relationship may be a spatial relationship between one or more first antenna ports of a base station that receive UL reference signals and one or more second antenna ports of the base station for DL ​​transmission to the UE. In some implementations, the UL reference signal may be a sounding reference signal (SRS) transmitted by the UE. The base station may estimate the channel condition and determine several channel estimation parameters based on the received SRS. The base station may configure or schedule DL resources using the channel estimation parameters determined from the SRS. In some aspects, the SRS may be part of a set of configured reference signal resources available to the UE.

[0086] In some implementations, the TCI state may also indicate a QCL relationship between a channel state information reference signal (CSI-RS) and one or more reference signals of a DL channel. In some aspects, the QCL relationship between the UL reference signal and the one or more reference signals of the physical downlink channel may be QCL type D, and the QCL relationship between the CSI-RS and the one or more reference signals of the physical downlink channel may be one of QCL type A, QCL type B, or QCL type C. As discussed above, the type D QCL relationship indicates the spatial relationship between the antenna port for receiving the UL signal and the antenna port for transmitting the DL data, and each of the QCL type A, QCL type B, and QCL type C relationships indicates one or more channel estimation parameters. For example, the QCL type A relationship indicates Doppler shift, Doppler spread, average delay, and delay spread, the QCL type B relationship indicates Doppler shift and Doppler spread, and the QCL type C relationship indicates Doppler shift and average delay.

[0087] The UL reference signal may be any suitable reference signal that a base station may use to estimate channel conditions or determine a number of channel estimation parameters. In some implementations, the UL reference signal may be an SRS transmitted from a UE, and the base station may determine the channel estimation parameters based on the SRS. In some aspects, the channel estimation parameters may include one or more of Doppler shift, Doppler spread, average spread, and average delay.

[0088] Figure 7AA flow chart depicting example operations 700 for wireless communication between a base station and a UE in accordance with various aspects of the present disclosure is shown. Operations 700 may be performed by a wireless communication device such as Figure 1 UE 104, Figure 3 UE 350 or Figure 5 In some implementations, operation 700 is performed at Figure 6 The process begins in block 606 before the UE receives downlink data. For example, in block 702, the UE receives a channel state information reference signal (CSI-RS) from a base station. In block 704, the UE determines a number of channel estimation parameters based on the received CSI-RS. In block 706, the UE decodes the downlink data based at least in part on the number of channel estimation parameters determined from the CSI-RS.

[0089] The CSI-RS transmitted to the UE may be a periodic CSI-RS, a semi-periodic CSI-RS, or an aperiodic CSI-RS. The UE may use the quality of the CSI-RS to determine the modulation and coding scheme (MCS) for UL transmission. Additionally or alternatively, the UE may use the CSI-RS signal to determine channel quality information (CQI) and rank indicator (RI) feedback. In some implementations, the base station may estimate the channel conditions based on the SRS received from the UE, derive a beamforming matrix based on the estimated channel conditions, and transmit the CSI-RS to the UE on the DL channel according to the beamforming matrix.

[0090] Figure 7B A flow chart depicting example operations 710 for wireless communication between a base station and a UE according to various aspects of the present disclosure is shown. Operations 710 may be performed by a wireless communication device. In some implementations, operations 710 may be performed by a wireless communication device. Figure 6 In some other implementations, operation 710 may be performed after the UE receives the TCI status in block 604. Figure 6 The operation 600 is separate from the operation 600 and may be performed at any suitable time. For example, at block 712, the UL beam indication and the DL beam indication may be concurrently changed based at least in part on the TCI state. In some implementations, the UL beam configuration and the DL beam configuration may be modified based on one or more TCI states transmitted from the base station in a DCI message.

[0091] Figure 8 8. A flowchart depicting example operations for wireless communication, a base station, and a UE according to various aspects of the present disclosure is shown. Operations 800 may be performed by a wireless communication device such as Figure 1 Base station 102, Figure 3 Base station 310 or Figure 5The base station 502 may be configured to schedule a physical downlink shared channel (PDSCH) based on the at least one TCI state associated with the set of uplink (UL) reference signals. At block 802, the base station configures a set of TCI states, the set of TCI states including at least one TCI state based on a set of uplink (UL) reference signals. At block 804, the base station receives the UL reference signals from a user equipment (UE). At block 806, the base station schedules a physical downlink shared channel (PDSCH) based on the at least one TCI state associated with the set of UL reference signals.

[0092] In some implementations, the configured set of TCI states may be provided to the UE as part of a radio resource control (RRC) configuration. The UL reference signal may be any suitable reference signal that a base station may use to estimate channel conditions or channel quality. In some aspects, the base station may determine several channel estimation parameters (such as Doppler shift, Doppler spread, average spread, and average delay) based on the UL reference signal. The channel estimation parameters may be used to determine the beamforming matrix, MCS, and other configurations for DL ​​transmissions to the UE.

[0093] In some implementations, the UL reference signal may be a sounding reference signal (SRS) used as a reference signal resource for at least one TCI state, and the at least one TCI state may indicate a QCL relationship between the SRS and one or more reference signals for the PDSCH. The at least one TCI state may also indicate a QCL relationship between the DL reference signal and one or more reference signals for the PDSCH. In some aspects, the DL reference signal may be a CSI-RS, and the at least one TCI state may indicate a QCL relationship between the CSI-RS and one or more reference signals for the PDSCH.

[0094] In some aspects, the base station may schedule DL transmissions on the PDSCH using a QCL relationship indicated by at least one TCI state.

[0095] Figure 9A A flow chart depicting example operations 900 for wireless communication between a base station and a UE in accordance with various aspects of the present disclosure is shown. Operations 900 may be performed by a wireless communication device such as Figure 1 Base station 102, Figure 3 Base station 310 or Figure 5 In some implementations, operation 900 is performed at Figure 8 The process begins after the base station schedules the PDSCH in block 806. For example, at block 902, the base station transmits at least one TCI state associated with the set of UL reference signals to the UE. At block 904, the base station transmits DL data to the UE on the scheduled PDSCH based at least in part on the at least one TCI state.

[0096] The TCI state that may be conveyed to the UE in a DCI message (or using some other suitable DL signaling) may indicate a QCL relationship between the SRS and the reference signal of the PDSCH. In some aspects, the QCL relationship may be a spatial relationship between the antenna ports of the base station used to receive the SRS and the antenna ports of the base station used to transmit DL data on the PDSCH. The UE may use the QCL indication to identify the beam selected by the base station for DL ​​transmission to the UE. In some implementations, the UE may infer, based on the presence of the QCL indication in the received TCI state, that the base station has or will schedule DL transmissions on the same beam as that used to receive the SRS from the UE.

[0097] The TCI state may also indicate a QCL relationship between a DL reference signal and one or more reference signals of the PDSCH. In some implementations, the QCL relationship may be between the CSI-RS and the DM-RS of the PDSCH. The UE may use the indicated QCL relationship between the CSI-RS and the DM-RS to decode the DL data transmitted by the base station on the PDSCH. More specifically, the UE may use one or more channel estimation parameters based on the CSI-RS to decode the DL data received from the base station on the PDSCH. In some aspects, the QCL relationship between the SRS and the PDSCH reference signal may be QCL type D, and the QCL relationship between the CSI-RS and the PDSCH reference signal may be one of QCL type A, QCL type B, or QCL type C.

[0098] Figure 9B A flow chart depicting example operations 910 for wireless communication between a base station and a UE in accordance with various aspects of the present disclosure is shown. Operations 910 may be performed by a wireless communication device such as Figure 1 Base station 102, Figure 3 Base station 310 or Figure 5 In some implementations, operation 910 is performed at Figure 8 The process begins after the base station receives a UL reference signal in block 804. For example, at block 912, the base station determines a plurality of channel estimation parameters based on the UL reference signal. At block 914, the base station configures at least one TCI state based at least in part on the plurality of channel estimation parameters determined from the UL reference signal.

[0099] In some implementations, the base station may determine one or more channel estimation parameters based on an SRS received from a UE on a UL channel. Channel estimation parameters, which may include one or more of Doppler shift, Doppler spread, average delay, or average spread, may be used by the base station for UL beam configuration and DL beam configuration. In some implementations, the base station may use one or more of the Doppler shift, Doppler spread, average delay, or average spread determined from the SRS to configure at least one TCI state. Additionally or alternatively, the base station may use the SRS-based channel estimation parameters to determine a beamforming matrix for CSI-RS transmission to the UE.

[0100] Figure 9C A flow chart depicting example operations 920 for wireless communication between a base station and a UE in accordance with various aspects of the present disclosure is shown. Operations 920 may be performed by a wireless communication device such as Figure 1 Base station 102, Figure 3 Base station 310 or Figure 5 In some implementations, operation 920 is performed at Figure 9A The process may begin after the base station transmits at least one TCI state to the UE in block 902. For example, at block 922, the UL beam indication and the DL beam indication may be concurrently changed based at least in part on the TCI state.

[0101] The following provides an overview of various aspects of the disclosure:

[0102] Aspect 1: A method for wireless communication performed by a UE, comprising: transmitting an uplink (UL) reference signal to a base station; receiving a transmission configuration indication (TCI) state based on the UL reference signal from the base station; and receiving DL data from the base station on a DL channel based at least in part on the TCI state.

[0103] Aspect 2: The method of Aspect 1, wherein the UL reference signal is used as a reference signal resource in the TCI state.

[0104] Aspect 3: The method of aspect 2, wherein the QCL relationship includes a spatial relationship between one or more first antenna ports for receiving UL reference signals and one or more second antenna ports for transmitting DL data.

[0105] Aspect 4: The method of Aspect 3, wherein the UE transmits SRS and receives DL data on the same beam indicated by the TCI state.

[0106] Aspect 5: A method as in Aspect 4, wherein the QCL relationship between the UL reference signal and one or more reference signals of the DL channel includes a QCL type D relationship, and the QCL relationship between the CSI-RS and one or more reference signals of the DL channel includes one of a QCL type A relationship, a QCL type B relationship, or a QCL type C relationship.

[0107] Aspect 6: The method of any one of aspects 4 to 5, wherein the QCL relationship comprises an RRC configuration.

[0108] Aspect 7: The method of aspect 6, wherein the plurality of channel estimation parameters include one or more of Doppler shift, Doppler spread, average delay, or average spread.

[0109] Aspect 8: The method of any one of Aspects 4 to 7, further comprising: receiving a CSI-RS from a base station; determining a plurality of channel estimation parameters based on the CSI-RS; and decoding DL data based at least in part on the plurality of channel estimation parameters determined from the CSI-RS.

[0110] Aspect 9: The method of any one of aspects 2 to 8, wherein the UL reference signal comprises an SRS, the DL channel comprises a PDSCH, and the one or more reference signals comprises a demodulation reference signal (DM-RS) of the PDSCH.

[0111] Aspect 10: The method of any one of aspects 2 to 9, wherein the TCI status further indicates a QCL relationship between a channel state information reference signal (CSI-RS) and one or more reference signals of a DL channel.

[0112] Aspect 11: The method of any one of aspects 1 to 10, wherein the TCI state indicates a quasi co-location (QCL) relationship between a UL reference signal and one or more reference signals of a DL channel.

[0113] Aspect 12: The method of any one of aspects 1 to 11, wherein the TCI status is received from the base station in a DCI message.

[0114] Aspect 13: The method of any one of aspects 1 to 12, wherein the TCI state is part of a set of TCI states configured by RRC.

[0115] Aspect 14: The method of any one of aspects 1 to 13, further comprising: concurrently modifying the UL beam configuration and the DL beam configuration based on the TCI status.

[0116] Aspect 15: The method of any one or more of aspects 1 to 14, wherein the UL reference signal comprises an SRS.

[0117] Aspect 16: A method for wireless communication performed by a base station, comprising: receiving an UL reference signal from a UE; configuring a set of transmission configuration indication (TCI) states, the set of TCI states including at least one TCI state based at least in part on a received uplink (UL) reference signal; and scheduling a PDSCH based at least in part on at least one TCI state associated with the received UL reference signal.

[0118] Aspect 17: A method as in Aspect 16, wherein execution of the instructions causes the base station to perform operations further including: transmitting at least one TCI state associated with the received UL reference signal to the UE; and transmitting DL data to the UE on the scheduled PDSCH based at least in part on the at least one TCI state.

[0119] Aspect 18: The method of Aspect 17, wherein the at least one TCI state is transmitted to the UE in a DCI message.

[0120] Aspect 19: The method of any one of aspects 17 to 18, wherein the TCI state indicates a quasi co-location (QCL) relationship between a UL reference signal and one or more reference signals of a PDSCH.

[0121] Aspect 20: The method of aspect 19, wherein the QCL relationship comprises a spatial relationship between one or more first antenna ports for receiving UL reference signals and one or more second antenna ports for transmitting DL data on the PDSCH.

[0122] Aspect 21: The method of any one of aspects 16 to 20, wherein the UL reference signal is used as a reference signal resource of the TCI state.

[0123] Aspect 22: The method of aspect 21, wherein the UL reference signal comprises an SRS, and the one or more reference signals comprises a demodulation reference signal (DM-RS) of a PDSCH.

[0124] Aspect 23: The method of aspect 22, wherein the UE transmits the SRS and receives the DL data on the same beam indicated by the TCI state.

[0125] Aspect 24: The method of any one of aspects 16 to 23, wherein the TCI state further indicates a QCL relationship between a channel state information reference signal (CSI-RS) and one or more reference signals of the PDSCH.

[0126] Aspect 25: A method as in Aspect 24, wherein the QCL relationship between the UL reference signal and one or more reference signals of the PDSCH includes a QCL type D relationship, and the QCL relationship between the CSI-RS and one or more reference signals of the PDSCH includes one of a QCL type A relationship, a QCL type B relationship, or a QCL type C relationship.

[0127] Aspect 26: The method of any one of Aspects 24 to 25, wherein the QCL relationship comprises an RRC configuration.

[0128] Aspect 27: A method as described in any one of Aspects 16 to 26, wherein execution of the instructions causes the base station to perform operations further including: determining a number of channel estimation parameters based on a UL reference signal; and configuring at least one TCI state based at least in part on the number of channel estimation parameters determined from the UL reference signal.

[0129] Aspect 28: The method of Aspect 27, wherein the plurality of channel estimation parameters include one or more of Doppler shift, Doppler spread, average delay, or average spread.

[0130] Aspect 29: The method of any one of aspects 16 to 28, wherein execution of the instructions causes the base station to perform operations further comprising: concurrently changing the DL beam indication and the UL beam indication based at least in part on the TCI state.

[0131] Aspect 30: The method of any one or more of Aspects 35 to 48, wherein the UL reference signal comprises an SRS.

[0132] Aspect 31: An apparatus for wireless communication performed by a UE, comprising: a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform the method of any one of aspects 1 to 14.

[0133] Aspect 32: An apparatus for wireless communication performed by a UE, comprising at least one means for performing the method of any one of aspects 1 to 14.

[0134] Aspect 33: A non-transitory computer-readable medium storing code for wireless communication performed by a UE, the code comprising instructions executable by a processor to perform the method of any one of aspects 1 to 14.

[0135] Aspect 34: An apparatus comprising: a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform the method of any one of aspects 15 to 15.

[0136] Aspect 35: An apparatus comprising at least one means for performing the method of any one of Aspects 15 to 15.

[0137] Aspect 36: A non-transitory computer-readable medium storing code comprising instructions executable by a processor to perform the method of any one of aspects 15 to 15.

[0138] Aspect 37: An apparatus for wireless communication performed by a base station, comprising: a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform the method of any one of aspects 16 to 29.

[0139] Aspect 38: An apparatus for wireless communication performed by a base station, comprising at least one means for performing the method of any one of aspects 16 to 29.

[0140] Aspect 39: A non-transitory computer-readable medium storing code for wireless communication performed by a base station, the code comprising instructions executable by a processor to perform the method of any one of aspects 16 to 29.

[0141] Aspect 40: An apparatus comprising: a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform the method of any one of aspects 30 to 30.

[0142] Aspect 41: An apparatus comprising at least one means for performing the method of any one of aspects 30 to 30.

[0143] Aspect 42: A non-transitory computer-readable medium storing code comprising instructions executable by a processor to perform the method of any one of aspects 30 to 30.

[0144] As used herein, a phrase referring to "at least one" of a list of items refers to any combination of those items, including single members. As an example, "at least one of a, b, or c" is intended to encompass: a, b, c, ab, ac, bc, and abc.

[0145] The various illustrative logics, logic blocks, components, circuits, and algorithmic processes described in conjunction with the implementations disclosed herein may be implemented as electronic hardware, computer software, or a combination of both. This interchangeability of hardware and software has been generally described in terms of their functionality and illustrated in the various illustrative components, blocks, assemblies, circuits, and processes described above. Whether such functionality is implemented in hardware or software depends on the application and the design constraints imposed on the overall system.

[0146] The hardware and data processing apparatus for implementing the various illustrative logics, logic blocks, components, and circuits described in conjunction with the aspects disclosed herein may be implemented or performed using a general-purpose single-chip or multi-chip processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device designed to perform the functions described herein, discrete gate or transistor logic, discrete hardware components, or any combination thereof. A general-purpose processor may be a microprocessor, or any processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (such as a DSP combined with a microprocessor), multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. In some implementations, the processes and methods may be performed by circuitry dedicated to a given function.

[0147] In one or more aspects, the functions described may be implemented in hardware, digital electronic circuitry, computer software, firmware (including the structures disclosed in this specification and their structural equivalents), or any combination thereof. Implementations of the subject matter described in this specification may also be implemented as one or more computer programs, i.e., one or more components of computer program instructions encoded on computer storage media for execution by, or for controlling the operation of, data processing apparatus.

[0148] If implemented in software, each function can be stored as one or more instructions or codes on a computer-readable medium or transmitted therethrough. The process of the method or algorithm disclosed herein can be implemented in a processor-executable software component that can reside on a computer-readable medium. Computer-readable media include both computer storage media and communication media, including any medium that can be implemented to transfer a computer program from one place to another. The storage medium can be any available medium that can be accessed by a computer. As an example and not limitation, such computer-readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired program code in the form of an instruction or data structure and can be accessed by a computer. Any connection can also be appropriately referred to as a computer-readable medium. As used herein, disks and discs include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), floppy disks and blue-ray discs, wherein disks often reproduce data magnetically and discs reproduce data optically with lasers. The above combination should also be included in the scope of computer-readable media. Additionally, the operations of a method or algorithm may reside as one or any combination or set of codes and instructions on a machine-readable medium or computer-readable medium, which may be incorporated into a computer program product.

[0149] Various modifications to the implementations described in this disclosure may be apparent to those skilled in the art, and the general principles defined herein may be applied to other implementations without departing from the spirit or scope of the disclosure. Thus, the claims are not intended to be limited to the implementations shown herein, but should be accorded the widest scope consistent with this disclosure, the principles, and novel features disclosed herein.

Claims

1. A method for wireless communication at a user equipment (UE), comprising: transmitting an uplink reference signal to an access network node via a first beam, wherein the uplink reference signal includes resources mapped to a transmission configuration indication state, the transmission configuration indication state indicating a quasi-co-located (QCL) relationship between the uplink reference signal and one or more downlink reference signals associated with one or more downlink transmissions; receiving, from the access network node, the transmission configuration indication state from a set of transmission configuration indication states based at least in part on the uplink reference signal, the transmission configuration indication state indicating the first beam; as well as The one or more downlink transmissions are received from the access network node on a downlink channel via the first beam based at least in part on the transmission configuration indication state, the one or more downlink transmissions comprising downlink data.

2. The method according to claim 1, wherein The uplink reference signal is used as a reference signal resource of the transmission configuration indication state.

3. The method according to claim 2, wherein: The QCL relationship includes a spatial relationship between one or more first antenna ports for receiving the uplink reference signal and one or more second antenna ports for transmitting the downlink data.

4. The method according to claim 2, wherein: The uplink reference signal comprises a sounding reference signal, the downlink channel comprises a physical downlink shared channel, and the one or more downlink reference signals comprise a demodulation reference signal of the physical downlink shared channel.

5. The method according to claim 2, wherein: The transmission configuration indication state further indicates a quasi-co-located (QCL) relationship between a channel state information reference signal and the one or more reference signals of the downlink channel.

6. The method of claim 1, wherein: The QCL relationship between the uplink reference signal and the one or more reference signals of the downlink channel comprises a QCL type D relationship.

7. The method according to claim 5, wherein: The QCL relationship between the channel state information reference signal and the one or more reference signals of the downlink channel includes one of a QCL Type A relationship, a QCL Type B relationship, or a QCL Type C relationship.

8. The method of claim 1, wherein: The QCL relationship includes a radio resource control configuration.

9. The method of claim 1, further comprising: receiving a channel state information reference signal from the access network node; determining a plurality of channel estimation parameters based at least in part on the channel state information reference signal; as well as The downlink data is decoded based at least in part on the number of channel estimation parameters determined from the channel state information reference signal.

10. The method of claim 9, wherein: The plurality of channel estimation parameters include one or more of Doppler shift, Doppler spread, average delay, or average spread.

11. The method of claim 1, wherein: The transmission configuration indication status is received from the access network node in a downlink control information message.

12. The method of claim 1, wherein: The transmission configuration indication state is part of a set of transmission configuration indication states configured by radio resource control.

13. The method of claim 1, further comprising: An uplink beam configuration and a downlink beam configuration are concurrently modified based on the transmission configuration indication status.

14. The method of claim 1, wherein: The uplink reference signal includes a sounding reference signal.

15. A method for wireless communication at an access network node, comprising: receiving an uplink reference signal from a user equipment (UE) via a first beam, wherein the uplink reference signal comprises resources mapped to at least one transmission configuration indication state, the transmission configuration indication state indicating a quasi-co-located (QCL) relationship between the uplink reference signal and one or more downlink reference signals associated with one or more downlink transmissions on a physical downlink shared channel; configuring a set of transmission configuration indication states, the set of transmission configuration indication states including the at least one transmission configuration indication state based at least in part on a received uplink reference signal, the at least one transmission configuration indication state indicating the first beam; as well as The physical downlink shared channel is scheduled via the first beam based at least in part on the at least one transmission configuration indication state associated with the received uplink reference signal.

16. The method of claim 15, further comprising: transmitting, to the UE, the at least one transmission configuration indication status associated with the received uplink reference signal; as well as Downlink data is transmitted to the UE on a scheduled physical downlink shared channel based at least in part on the at least one transmission configuration indication state.

17. The method of claim 16, wherein: The at least one transmission configuration indication status is transmitted to the UE in a downlink control information message.

18. The method of claim 15, wherein: The uplink reference signal includes a sounding reference signal and is a reference signal resource that indicates a state of a transmission configuration associated with a received reference signal including a demodulation reference signal of the physical downlink shared channel.

19. The method of claim 16, wherein: The transmission configuration indication state indicates a quasi-co-located (QCL) relationship between the uplink reference signal and one or more reference signals of the physical downlink shared channel.

20. The method of claim 19, wherein: The QCL relationship includes a spatial relationship between one or more first antenna ports for receiving the uplink reference signal and one or more second antenna ports for transmitting the downlink data on the physical downlink shared channel.

21. The method of claim 15, wherein: The transmission configuration indication state further indicates a quasi-co-located (QCL) relationship between a channel state information reference signal and the one or more reference signals of the physical downlink shared channel.

22. The method of claim 15, wherein: The QCL relationship between the uplink reference signal and the one or more reference signals of the physical downlink shared channel includes a QCL type D relationship.

23. The method of claim 21, wherein: A QCL relationship between the channel state information reference signal and the one or more reference signals of the physical downlink shared channel includes one of a QCL type A relationship, a QCL type B relationship, or a QCL type C relationship.

24. The method of claim 15, wherein: The QCL relationship includes a radio resource control configuration.

25. The method of claim 15, further comprising: determining a number of channel estimation parameters based at least in part on the uplink reference signal, wherein the number of channel estimation parameters comprises one or more of Doppler shift, Doppler spread, average delay, or average spread; and The at least one transmission configuration indication state is configured based at least in part on the number of channel estimation parameters determined from the uplink reference signal.

26. The method of claim 15, further comprising: A downlink beam indication and an uplink beam indication are concurrently changed based at least in part on the transmission configuration indication state.

27. A device comprising: means for transmitting an uplink reference signal to an access network node via a first beam, wherein the uplink reference signal comprises resources mapped to a transmission configuration indication state, the transmission configuration indication state indicating a quasi-co-located (QCL) relationship between the uplink reference signal and one or more downlink reference signals associated with one or more downlink transmissions; means for receiving, from the access network node, the transmission configuration indication state from a set of transmission configuration indication states based at least in part on the uplink reference signal, the transmission configuration indication state indicating the first beam; as well as Means for receiving the one or more downlink transmissions from the access network node on a downlink channel via the first beam based at least in part on the transmission configuration indication state, the one or more downlink transmissions comprising downlink data.

28. The apparatus of claim 27, wherein: The uplink reference signal is used as a reference signal resource of the transmission configuration indication state.

29. The apparatus of claim 28, wherein The QCL relationship includes a spatial relationship between one or more first antenna ports for receiving the uplink reference signal and one or more second antenna ports for transmitting the downlink data.

30. The apparatus of claim 28, wherein The uplink reference signal comprises a sounding reference signal, the downlink channel comprises a physical downlink shared channel, and the one or more downlink reference signals comprise a demodulation reference signal of the physical downlink shared channel.

31. The apparatus of claim 28, wherein: The transmission configuration indication state further indicates a quasi-co-located (QCL) relationship between a channel state information reference signal and the one or more reference signals of the downlink channel.

32. The apparatus of claim 27, wherein: The QCL relationship between the uplink reference signal and the one or more reference signals of the downlink channel comprises a QCL type D relationship.

33. The apparatus of claim 31, wherein: The QCL relationship between the channel state information reference signal and the one or more reference signals of the downlink channel includes one of a QCL Type A relationship, a QCL Type B relationship, or a QCL Type C relationship.

34. The apparatus of claim 27, wherein: The QCL relationship includes a radio resource control configuration.

35. The apparatus of claim 27, further comprising: means for receiving a channel state information reference signal from said access network node; means for determining a plurality of channel estimation parameters based at least in part on the channel state information reference signal; as well as Means for decoding the downlink data based at least in part on the number of channel estimation parameters determined from the channel state information reference signal.

36. The apparatus of claim 35, wherein: The plurality of channel estimation parameters include one or more of Doppler shift, Doppler spread, average delay, or average spread.

37. The apparatus of claim 27, wherein: The transmission configuration indication status is received from the access network node in a downlink control information message.

38. The apparatus of claim 27, wherein: The transmission configuration indication state is part of a set of transmission configuration indication states configured by radio resource control.

39. The apparatus of claim 27, further comprising: Means for concurrently modifying an uplink beam configuration and a downlink beam configuration based on the transmission configuration indication status.

40. The apparatus of claim 27, wherein: The uplink reference signal includes a sounding reference signal.

41. A device comprising: means for receiving an uplink reference signal from a user equipment (UE) via a first beam, wherein the uplink reference signal comprises resources mapped to at least one transmission configuration indication state, the transmission configuration indication state indicating a quasi-co-located (QCL) relationship between the uplink reference signal and one or more downlink reference signals associated with one or more downlink transmissions on a physical downlink shared channel; means for configuring a set of transmission configuration indication states, the set of transmission configuration indication states including the at least one transmission configuration indication state based at least in part on a received uplink reference signal, the at least one transmission configuration indication state indicating the first beam; as well as means for scheduling the physical downlink shared channel via the first beam based on the at least one transmission configuration indication state associated with the received uplink reference signal.

42. The apparatus of claim 41 , further comprising: means for transmitting the at least one transmission configuration indication status associated with the received uplink reference signal to the UE; as well as means for transmitting downlink data to the UE on a scheduled physical downlink shared channel based at least in part on the at least one transmission configuration indication state.

43. The apparatus of claim 42, wherein: The at least one transmission configuration indication status is transmitted to the UE in a downlink control information message.

44. The apparatus of claim 41, wherein The uplink reference signal includes a sounding reference signal and is a reference signal resource that indicates a state of a transmission configuration associated with a received reference signal including a demodulation reference signal of the physical downlink shared channel.

45. The apparatus of claim 42, wherein: The transmission configuration indication state indicates a quasi-co-located (QCL) relationship between the uplink reference signal and one or more reference signals of the physical downlink shared channel.

46. ​​The apparatus of claim 45, wherein The QCL relationship includes a spatial relationship between one or more first antenna ports for receiving the uplink reference signal and one or more second antenna ports for transmitting the downlink data on the physical downlink shared channel.

47. The apparatus of claim 41, wherein The transmission configuration indication state further indicates a quasi-co-located (QCL) relationship between a channel state information reference signal and the one or more reference signals of the physical downlink shared channel.

48. The apparatus of claim 41, wherein The QCL relationship between the uplink reference signal and the one or more reference signals of the physical downlink shared channel includes a QCL type D relationship.

49. The apparatus of claim 47, wherein: A QCL relationship between the channel state information reference signal and the one or more reference signals of the physical downlink shared channel includes one of a QCL type A relationship, a QCL type B relationship, or a QCL type C relationship.

50. The apparatus of claim 41, wherein The QCL relationship includes a radio resource control configuration.

51. The apparatus of claim 41 , further comprising: means for determining a number of channel estimation parameters based at least in part on the uplink reference signal, wherein the number of channel estimation parameters comprises one or more of Doppler shift, Doppler spread, average delay, or average spread; as well as means for configuring the at least one transmission configuration indication state based at least in part on the number of channel estimation parameters determined from the uplink reference signal.

52. The apparatus of claim 41 , further comprising: Means for concurrently changing a downlink beam indication and an uplink beam indication based at least in part on the transmission configuration indication state.

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