Techniques for configuring transmit configuration indicator (TCI) states for multiple transmit / receive points

Abstract

Aspects described herein relate to a user equipment (UE) or other device receiving, based on a maximum number of transmit configuration indicator (TCI) states, an indication of one or more TCI states of coherent joint transmissions (CJT) from at least a portion of a plurality of transmit / receive points (TRPs) configurable for the UE. One or more downlink reference signals may be received from at least the portion of the plurality of TRPs based on the indication, and a power delay profile (PDP) or Doppler spectrum for channel estimation for at least a portion of the one or more TCI states may be derived based on the one or more downlink reference signals. Other aspects relate to transmitting an indication of TCI status and / or a reference signal.

Description

Technical Field

[0001] Aspects of the present disclosure relate generally to wireless communication systems, and more particularly to techniques for configuring transmit configuration indicator (TCI) states.

[0002] Related technologies

[0003] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, broadcast, etc. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), and single-carrier frequency division multiple access (SC-FDMA) systems.

[0004] 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. For example, the fifth generation (5G) wireless communication technology, which may be referred to as 5G New Radio (5GNR), is designed to expand and support diverse usage scenarios and applications for current mobile network generations. In one aspect, 5G communication technology may include: enhanced mobile broadband addressing people-centric use cases for accessing multimedia content, services, and data; ultra-reliable low-latency communications (URLLC) with certain specifications for latency and reliability; and massive machine-type communications that may allow for a very large number of connected devices and the transmission of relatively small amounts of non-latency-sensitive information.

[0005] In some wireless communication technologies (such as 5G NR), a network node may configure a Transmission Configuration Indicator (TCI) state to facilitate quasi-co-location (QCL) association between reference signals used for channel estimation. A UE may receive the configuration of the TCI state and, from the configuration, may activate the TCI state to perform channel estimation for certain downlink data signals. Additionally, in 5G NR, a UE may be configured to receive downlink signals from multiple transmit / receive points (TRPs) using coherent joint transmission (CJT). Summary of the Invention

[0006] The following presents a summary of one or more aspects in order to provide a basic understanding of these aspects. This summary is not an extensive overview of all contemplated aspects and is neither intended to identify key or critical elements of all aspects nor to describe the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

[0007] According to one aspect, an apparatus for wireless communication is provided, the apparatus comprising: a processor; a memory coupled to the processor; and instructions stored in the memory. The instructions, when executed by the processor, are operable to cause the apparatus to: send user equipment (UE) capabilities to a network node, the user equipment (UE) capabilities indicating a maximum number of active transmit configuration indicator (TCI) states supported for coherent joint transmission (CJT) from a plurality of transmit receive points (TRPs); receive, from the network node and based on the maximum number of TCI states, an indication of one or more TCI states for CJT from at least a portion of the plurality of TRPs; receive one or more downlink reference signals from at least the portion of the plurality of TRPs based on the indication; and derive a power delay profile (PDP) or Doppler spectrum for channel estimation for at least a portion of the one or more TCI states based on the one or more downlink reference signals.

[0008] In another aspect, an apparatus for wireless communication is provided, the apparatus comprising: a processor; a memory coupled to the processor; and instructions stored in the memory. The instructions, when executed by the processor, are operable to cause the apparatus to: receive, for a UE, UE capabilities indicating a maximum number of active TCI states supported for CJTs from a plurality of TRPs; send, to the UE and based on the maximum number of TCI states, an indication of one or more TCI states for CJTs from at least a portion of the plurality of TRPs; and send, based on the indication, one or more downlink reference signals from at least the portion of the plurality of TRPs.

[0009] On the other hand, a method for wireless communication at a UE is provided, the method comprising: sending UE capabilities to a network node, the UE capabilities indicating a maximum number of active TCI states supported for CJTs from multiple TRPs; receiving, from the network node and based on the maximum number of TCI states, an indication of one or more TCI states for CJTs from at least a portion of the multiple TRPs; receiving one or more downlink reference signals from at least the portion of the multiple TRPs based on the indication; and deriving a PDP or Doppler spectrum for channel estimation for at least a portion of the one or more TCI states based on the one or more downlink reference signals.

[0010] On the other hand, a method for wireless communication at a network node is provided, the method comprising: for a UE, receiving a UE capability indicating a maximum number of active TCI states supported for a CJT from a plurality of TRPs; sending, to the UE and based on the maximum number of TCI states, an indication of one or more TCI states for a CJT from at least a portion of the plurality of TRPs; and sending one or more downlink reference signals from at least the portion of the plurality of TRPs based on the indication.

[0011] In another example, an apparatus for wireless communication is provided, the apparatus comprising a transceiver, a memory configured to store instructions, and one or more processors communicatively coupled to the transceiver and the memory. The one or more processors are configured to execute the instructions to perform the operations of the methods described herein. In another aspect, an apparatus for wireless communication is provided, the apparatus comprising means for performing the operations of the methods described herein. In yet another aspect, a computer-readable medium comprising code executable by one or more processors to perform the operations of the methods described herein is provided.

[0012] To accomplish the foregoing and related ends, one or more aspects include the features fully described below and particularly pointed out in the claims. The following description and the accompanying drawings set forth in detail certain illustrative features of one or more aspects. However, these features are indicative of but a few of the various ways in which the principles of the various aspects may be employed, and this description is intended to include all such aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The disclosed aspects will be described below with reference to the accompanying drawings, which are provided to illustrate and not to limit the disclosed aspects, wherein like numerals represent like elements, and in which:

[0014] Figure 1 An example of a wireless communication system according to various aspects of the present disclosure is illustrated;

[0015] Figure 2 is a diagram illustrating an example of a decomposed base station architecture according to various aspects of the present disclosure;

[0016] Figure 3 is a block diagram illustrating an example of a user equipment (UE) according to various aspects of the present disclosure;

[0017] Figure 4 is a block diagram illustrating an example of a base station according to various aspects of the present disclosure;

[0018] Figure 5is a flow chart illustrating an example of a method for using or managing configuration of multiple transmit configuration indicator (TCI) states for coherent joint transmission (CJT) from multiple transmit / receive points (TRPs) in accordance with aspects described herein;

[0019] Figure 6 is a flow chart illustrating an example of a method for configuring a UE to use or manage configuration of multiple TCI states for CJTs from multiple TRPs in accordance with aspects described herein;

[0020] Figure 7 illustrates examples of Power Delay Profile (PDP) spectra derived for various TRP or TCI state configurations in accordance with various aspects described herein; and

[0021] Figure 8 is a block diagram illustrating an example of a Multiple Input Multiple Output (MIMO) communication system including a base station and UEs according to various aspects of the present disclosure. DETAILED DESCRIPTION

[0022] Various aspects will now be described with reference to the accompanying drawings. In the following description, for the purpose of explanation, numerous specific details are described in order to provide a thorough understanding of one or more aspects. However, it is apparent that such aspects may be practiced without these specific details.

[0023] The described features generally relate to configuring transmit configuration indicator (TCI) states for communication with multiple transmit / receive points (TRPs). In some wireless communication technologies, such as fifth generation (5G) new radio (NR), a device, such as a user equipment (UE), may be configured to communicate with multiple TRPs (e.g., up to four TRPs in some examples). For example, the UE may be configured to receive downlink transmissions (e.g., physical downlink shared channel (PDSCH) transmissions) from multiple TRPs, where the multiple TRPs may use coherent joint transmission (CJT) to transmit the downlink transmissions. In one example, assuming ideal backhaul and synchronization and the same number of antenna ports on the TRPs, enhancements to channel state information (CSI) acquisition (e.g., for one or more frequency ranges (FRs), such as FR1 in 5G NR) for CJT may be specified along with up to four TRPs. In one example, CJT may imply transmitting demodulation reference signal (DMRS) ports for PDSCH from multiple TRPs based on cross-TRP precoding. A subset of TRPs for PDSCH CJT transmission can be dynamically selected from up to a certain number of TRPs (e.g., 4 TRPs) based on CSI feedback in frequency division duplex (FDD) or sounding reference signal (SRS) measurements in time division duplex (TDD). Therefore, in some examples, TCI indication and corresponding UE loop operation may place a significant burden on the UE's tracking loop implementation based on tracking various TCI states for various TRP configurations.

[0024] Therefore, the aspects described herein relate to reducing the number of TCI states configured for a UE given a possible multiple TRP configurations. The UE may derive a power delay profile (PDP) or Doppler spectrum for channel estimation based on the reduced number of TCI states configured for the UE. For example, a network node may select and indicate one or more TCI states from the reduced number of TCI states for the selected number of TRPs. This may reduce the processing required for the UE to manage the TCI state loop, the amount of signaling required to update the TCI state loop for each of these TCI states, and the like. This, in turn, may improve the performance of the UE, save signaling resources, and communications between the UE and the network node, and the like. Such performance improvements may enhance the user experience when using the UE, the battery life of the UE, and the like.

[0025] The following will refer to Figures 1 to 8 The described features are presented in more detail.

[0026] As used in this application, the terms "component," "module," "system," and the like are intended to include computer-related entities such as, but not limited to, hardware, firmware, a combination of hardware and software, software, or software in execution. For example, a component can be, but is not limited to, a process running on a processor, a processor, an object, an executable file, a thread of execution, a program, and / or a computer. By way of example, both an application running on a computing device and a computing device can be components. One or more components can exist in a process and / or thread of execution, and a component can be located in one computer and / or distributed between two or more computers. In addition, these components can be executed from various computer-readable media having various data structures stored thereon. Components can communicate by means of local and / or remote processes, such as based on signals having one or more data packets (such as data from a component that interacts with a local system, another component in a distributed system, and / or interacts with other systems across a network such as the Internet).

[0027] The technology described herein can be used in various wireless communication systems, such as CDMA, TDMA, FDMA, OFDMA, single-carrier FDMA, and other systems. The terms "system" and "network" are often used interchangeably. A CDMA system can implement radio technologies such as CDMA2000, Universal Terrestrial Radio Access (UTRA), and the like. CDMA2000 covers IS-2000, IS-95, and IS-856 standards. IS-2000 versions 0 and A are commonly referred to as CDMA2000 1X, 1X, and the like. IS-856 (TIA-856) is commonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD), and the like. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. A TDMA system can implement radio technologies such as Global System for Mobile Communications (GSM). An OFDMA system may implement radio technologies such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, etc. TMetc. UTRA and E-UTRA are part of the Universal Mobile Telecommunications System (UMTS). 3GPP Long Term Evolution (LTE) and Advanced LTE (LTE-A) are new versions of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from an organization called the "3rd Generation Partnership Project" (3GPP). CDMA2000 and UMB are described in documents from an organization called the "3rd Generation Partnership Project 2" (3GPP2). The techniques described herein can be used for the above-mentioned systems and radio technologies as well as other systems and radio technologies, including cellular (e.g., LTE) communications on shared radio frequency spectrum bands. However, the following description describes an LTE / LTE-A system for example purposes, and LTE terminology is used in most of the following description, but these techniques can also be applied beyond LTE / LTE-A applications (e.g., to fifth generation (5G) new radio (NR) networks or other next generation communication systems).

[0028] The following description provides examples and does not limit the scope, applicability, or examples set forth in the claims. The functions and arrangements of the elements discussed may be changed without departing from the scope of this disclosure. Various examples may omit, replace, or add various processes or components as appropriate. For example, the methods described may be performed in a different order than described, and various steps may be added, omitted, or combined. In addition, features described with respect to some examples may be combined in other examples.

[0029] Various aspects or features will be presented with respect to systems that may include multiple devices, components, modules, etc. It should be understood and appreciated that the various systems may include additional devices, components, modules, etc. and / or may not include all of the devices, components, modules, etc. discussed in connection with the figures. Combinations of these methods may also be used.

[0030] Figure 1is a diagram illustrating an example of a wireless communication system and access network 100. The wireless communication system (also referred to as a wireless wide area network (WWAN)) may include a base station 102, a UE 104, an evolved packet core (EPC) 160, and / or a 5G core (5GC) 190. The base station 102 may include a macro cell (a high-power cellular base station) and / or a small cell (a low-power cellular base station). A macro cell may include a base station. A small cell may include a femto cell, a pico cell, and a micro cell. In one example, the base station 102 may also include a gNB 180, as further described herein. In one example, in accordance with various aspects described herein, some nodes of the wireless communication system may have a modem 340 and a UE communication component 342 for managing the configuration of a number of TCI states for a CJT using multiple TRPs, up to a maximum number. Additionally, in accordance with various aspects described herein, some nodes may have a modem 440 and a BS communication component 442 for configuring multiple TCI states for a UE for a CJT using multiple TRPs, up to a maximum number. Although UE 104 is shown as having a modem 340 and a UE communication component 342, and base station 102 / gNB 180 is shown as having a modem 440 and a BS communication component 442, this is an illustrative example, and substantially any node or type of node may include a modem 340 and a UE communication component 342 and / or a modem 440 and a BS communication component 442 to provide the corresponding functionality described herein.

[0031] Base stations 102 configured for 4G LTE (which may be collectively referred to as the Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) may interface with the EPC 160 via a backhaul link 132 (e.g., using an S1 interface). Base stations 102 configured for 5G NR (which may be collectively referred to as the Next Generation RAN (NG-RAN)) may interface with the 5GC 190 via a backhaul link 184. Among other functions, the base stations 102 may perform one or more of the following: transmission of user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., 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 warning messages. Base stations 102 may communicate with each other directly or indirectly (e.g., through EPC 160 or 5GC 190) over backhaul links 134 (e.g., using an X2 interface). Backhaul links 134 may be wired or wireless.

[0032] Base station 102 can wirelessly communicate with one or more UEs 104. Each of base stations 102 can provide communication coverage for a corresponding 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 may be referred to as a heterogeneous network. A heterogeneous network may also include a home evolved Node B (eNB) (HeNB), which can provide service to a restricted group (which may be referred to as a closed subscriber group (CSG)). The communication link 120 between base station 102 and UE 104 may include uplink (UL) (also known as reverse link) transmissions from UE 104 to base station 102 and / or downlink (DL) (also known as forward link) transmissions from base station 102 to UE 104. The communication link 120 may use multiple-input multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity. The communication link may be over one or more carriers. Base station 102 / UE 104 can use spectrum with a bandwidth of up to Y MHz (e.g., 5 MHz, 10 MHz, 15 MHz, 20 MHz, 100 MHz, 400 MHz, etc.) per carrier allocated in carrier aggregation for transmission in the DL and / or UL directions for a total of up to Yx MHz (e.g., corresponding to x component carriers). The carriers may be adjacent to each other or may not be adjacent to each other. The allocation of carriers may be asymmetric for DL ​​and UL (e.g., more or fewer carriers may be allocated for DL ​​than for 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).

[0033] In another example, some UEs 104 may communicate with each other using a device-to-device (D2D) communication link 158. The D2D communication link 158 may use the DL / UL WWAN spectrum. The D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), and a physical sidelink control channel (PSCCH). The D2D communication may be performed via 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.

[0034] The wireless communication system may also include a Wi-Fi access point (AP) 150 that communicates with a Wi-Fi station (STA) 152 via a communication link 154 in the 5 GHz unlicensed spectrum. 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.

[0035] The small cell 102' can operate in licensed and / or unlicensed spectrum. When operating in the unlicensed spectrum, the small cell 102' can employ NR and use the same 5 GHz unlicensed spectrum used by the Wi-Fi AP 150. The small cell 102' employing NR in the unlicensed spectrum can improve the coverage and / or increase the capacity of the access network.

[0036] Base station 102 (whether a small cell 102' or a large cell (e.g., a macro base station)) may include an eNB, gNodeB (gNB), or other type of base station. Some base stations, such as gNB 180, may operate in traditional sub-6 GHz spectrum, millimeter wave (mmW) frequencies, and / 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 base station. Extremely high frequency (EHF) is a portion of the RF portion of the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz, with wavelengths between 1 mm and 10 mm. Radio waves in this band may be referred to as millimeter waves. Near-mmW extends down to frequencies of 3 GHz with wavelengths 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 have extremely high path loss and short range. The mmW base station 180 can use beamforming 182 with the UE 104 to compensate for the extremely high path loss and short distance. The base station 102 mentioned herein can include a gNB 180.

[0037] 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 communicate 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, and / or other IP services. BM-SC 170 can provide functionality for configuring and delivering MBMS user services. BM-SC 170 can serve as the entry point for content providers' MBMS delivery, authorize and initiate MBMS bearer services in the Public Land Mobile Network (PLMN), and schedule MBMS delivery. MBMS Gateway 168 can distribute MBMS services to base stations 102 within a Multicast Broadcast Single Frequency Network (MBSFN) area that broadcasts specific services, and can be responsible for session management (start / stop) and collecting eMBMS-related billing information.

[0038] 5GC 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. AMF 192 may communicate with a unified data management (UDM) 196. AMF 192 may be a control node that handles signaling between UE 104 and 5GC 190. Generally, AMF 192 may provide QoS flow and session management. User Internet Protocol (IP) packets (e.g., from one or more UEs 104) may be transported through UPF 195. UPF 195 may provide UE IP address allocation and other functions for one or more UEs. UPF 195 is connected to IP services 197. IP services 197 may include the Internet, an intranet, an IP multimedia subsystem (IMS), PS streaming services, and / or other IP services.

[0039] A base station may also be referred to as a gNB, Node B, evolved Node B (eNB), access point, base transceiver station, radio base station, radio transceiver, transceiver function, basic service set (BSS), extended service set (ESS), transmit receive point (TRP), or some other suitable terminology. Base station 102 provides an access point to EPC 160 or 5GC 190 for UE 104. 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 (e.g., an MP3 player), a camera, a game console, a tablet, 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 of UE 104 may be referred to as IoT devices (e.g., a parking meter, a gas pump, a toaster, a vehicle, a heart monitor, etc.). IoT UEs may include machine type communication (MTC) / enhanced MTC (eMTC, also known as Category (CAT)-M or Cat M1) UEs, NB-IoT (also known as CAT NB1) UEs, and other types of UEs. In the present disclosure, eMTC and NB-IoT may refer to future technologies that may evolve from or be based on these technologies. For example, eMTC may include FeMTC (further eMTC), eFeMTC (enhanced further eMTC), mMTC (massive MTC), etc., and NB-IoT may include eNB-IoT (enhanced NB-IoT), FeNB-IoT (further enhanced NB-IoT), etc. UE 104 may also be referred to as a station, mobile station, subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable terminology.

[0040] The deployment of a communication system (such as a 5G New Radio (NR) system) can be arranged with various components or constituent parts in a variety of ways. In a 5G NR system or network, a network node, a network entity, a mobility element of a network, a radio access network (RAN) node, a core network node, a network element or network equipment (such as a base station (BS, e.g., BS102), or one or more units (or one or more components) that perform base station functionality can be implemented in a converged architecture or a decomposed architecture. For example, a BS (such as a Node B (NB), an evolved NB (eNB), an NR BS, a 5G NB, an access point (AP), a transmit receive point (TRP), or a cell, etc.) can be implemented as a converged base station (also known as a standalone BS or a monolithic BS) or a decomposed base station.

[0041] A converged base station may be configured to utilize a radio protocol stack that is physically or logically integrated within a single RAN node. A decomposed base station may be configured to utilize a protocol stack that is physically or logically distributed between two or more units, such as one or more central or centralized units (CUs), one or more distributed units (DUs), or one or more radio units (RUs). In some aspects, a CU may be implemented within a RAN node, and one or more DUs may be co-located with the CU, or alternatively, may be geographically or virtually distributed across one or more other RAN nodes. A DU may be implemented to communicate with one or more RUs. Each of the CUs, DUs, and RUs may also be implemented as a virtual unit, namely a virtual central unit (VCU), a virtual distributed unit (VDU), or a virtual radio unit (VRU).

[0042] Base station type operation or network design can take into account the aggregated nature of base station functionality. For example, a disaggregated base station can be used in an integrated access backhaul (IAB) network, an open radio access network (O-RAN (a network configuration such as that initiated by the O-RAN Alliance)), or a virtualized radio access network (vRAN, also known as a cloud radio access network (C-RAN)). Decomposition can include distributing functionality across two or more units at various physical locations, as well as virtually distributing functionality of at least one unit, which can enable flexibility in network design. Each unit of a disaggregated base station or disaggregated RAN architecture can be configured for wired or wireless communication with at least one other unit.

[0043] In one example, the UE communication component 342 can receive, for example, from the BS communication component 442 of the network node, an indication of one or more TCI states for CJT based on at least a portion of the plurality of TRPs. The indication can be based on a maximum number of active TCI states supported for CJT, which can be at least one of: indicated by the UE communication component 342, based on a wireless communication technology standard, or otherwise stored in a memory of the UE 104. In addition, in one example, the UE communication component 342 can receive, for example, from the BS communication component 442 of the network node, a configuration of a reduced number of TCI states (e.g., up to the maximum number of active TCI states supported for CJT), and the BS communication component 442 can indicate an indication of one or more TCI states from the configuration based on the selected number of TRP configurations. In one example, the UE communication component 342 can receive, for example, from the BS communication component 442, one or more reference signals and can derive a PDP or Doppler spectrum for at least a portion of the one or more TCI states based on the one or more reference signals.

[0044] Figure 2 A diagram illustrating an example of a disaggregated base station 200 architecture is shown. The disaggregated base station 200 architecture may include one or more central units (CUs) 210 that may communicate directly with a core network 220 via a backhaul link, or indirectly with the core network 220 through one or more disaggregated base station units, such as a near real-time (near-RT) RAN intelligent controller (RIC) 225 via an E2 link, or a non-real-time (non-RT) RIC 215 associated with a service management and orchestration (SMO) framework 205, or both. The CU 210 may communicate with one or more distributed units (DUs) 230 via corresponding midhaul links, such as an F1 interface. The DU 230 may communicate with one or more radio units (RUs) 240 via corresponding fronthaul links. The RU 240 may communicate with corresponding UEs 104 via one or more radio frequency (RF) access links. In some implementations, a UE 104 may be served simultaneously by multiple RUs 240.

[0045] Each of the units (e.g., CU 210, DU 230, RU 240, and near-RT RIC 225, non-RT RIC 215, and SMO framework 205) may include or be coupled to one or more interfaces configured to receive or transmit signals, data, or information (collectively, signals) via a wired or wireless transmission medium. Each of these units, or an associated processor or controller that provides instructions to the communication interface of these units, may be configured to communicate with one or more of the other units via the transmission medium. For example, the unit may include a wired interface configured to receive or transmit signals to one or more of the other units over the wired transmission medium. Additionally, these units may include a wireless interface that may include a receiver, transmitter, or transceiver (such as a radio frequency (RF) transceiver) configured to receive or transmit signals, or both, to one or more of the other units over the wireless transmission medium.

[0046] In some aspects, the CU 210 may host one or more higher layer control functions. Such control functions may include radio resource control (RRC), packet data convergence protocol (PDCP), service data adaptation protocol (SDAP), etc. Each control function may be implemented using an interface that is configured to communicate signals with other control functions hosted by the CU 210. The CU 210 may be configured to handle user plane functionality (i.e., central unit-user plane (CU-UP)), control plane functionality (i.e., central unit-control plane (CU-CP)), or a combination thereof. In some specific implementations, the CU 210 may be logically split into one or more CU-UP units and one or more CU-CP units. When implemented in an O-RAN configuration, the CU-UP unit may communicate bidirectionally with the CU-CP unit via an interface (such as an E1 interface). As needed, the CU 210 may be implemented to communicate with the DU 230 for network control and signaling.

[0047] The DU 230 may correspond to a logical unit that includes one or more base station functions for controlling the operation of one or more RUs 240. In some aspects, the DU 230 may host one or more of a radio link control (RLC) layer, a medium access control (MAC) layer, and one or more higher physical (PHY) layers (such as modules for forward error correction (FEC) encoding and decoding, scrambling, modulation and demodulation, etc.), depending at least in part on a functional split such as that defined by the Third Generation Partnership Project (3GPP). In some aspects, the DU 230 may also host one or more lower PHY layers. Each layer (or module) may be implemented using an interface configured to communicate signals with other layers (and modules) hosted by the DU 230 or with control functions hosted by the CU 210.

[0048] Lower layer functionality may be implemented by one or more RUs 240. In some deployments, a RU 240 controlled by a DU 230 may correspond to a logical node that hosts RF processing functionality or low PHY layer functionality (such as performing Fast Fourier Transform (FFT), Inverse FFT (iFFT), digital beamforming, Physical Random Access Channel (PRACH) extraction and filtering, etc.), or both, based at least in part on a functional split (such as a lower layer functional split). In such an architecture, the RU 240 may be implemented to handle over-the-air (OTA) communications with one or more UEs 104. In some implementations, real-time and non-real-time aspects of control and user plane communications with the RU 240 may be controlled by the corresponding DU 230. In some scenarios, this configuration may enable the implementation of the DU 230 and CU 210 in a cloud-based RAN architecture (such as a vRAN architecture).

[0049] The SMO framework 205 can be configured to support RAN deployment and provisioning of both non-virtualized and virtualized network elements. For non-virtualized network elements, the SMO framework 205 can be configured to support the deployment of dedicated physical resources for RAN coverage requirements, which can be managed via an operations and maintenance interface (such as the O1 interface). For virtualized network elements, the SMO framework 205 can be configured to interact with a cloud computing platform (such as Open Cloud (O-Cloud) 290) to perform network element lifecycle management (such as to instantiate virtualized network elements) via a cloud computing platform interface (such as the O2 interface). Such virtualized network elements may include, but are not limited to, the CU 210, DU 230, RU 240, and near-RT RIC 225. In some implementations, the SMO framework 205 can communicate with hardware aspects of the 4G RAN (such as the Open eNB (O-eNB) 211) via the O1 interface. Additionally, in some implementations, the SMO framework 205 can communicate directly with one or more RUs 240 via the O1 interface. The SMO framework 205 may also include a non-RT RIC 215 configured to support the functionality of the SMO framework 205 .

[0050] The non-RT RIC 215 may be configured to include logic that enables non-real-time control and optimization of RAN elements and resources, artificial intelligence / machine learning (AI / ML) workflows including model training and updating, or policy-based guidance of applications / features in the near-RT RIC 225. The non-RT RIC 215 may be coupled to or in communication with the near-RT RIC 225 (e.g., via an A1 interface). The near-RT RIC 225 may be configured to include logic that enables near-real-time control and optimization of RAN elements and resources through data collection and actions over an interface (e.g., via an E2 interface) that connects one or more CUs 210, one or more DUs 230, or both, and the O-eNB with the near-RT RIC 225.

[0051] In some implementations, the non-RT RIC 215 may receive parameters or external enrichment information from an external server in order to generate an AI / ML model to be deployed in the near-RT RIC 225. This information may be utilized by the near-RT RIC 225 and may be received from a non-network data source or from a network function at the SMO framework 205 or the non-RT RIC 215. In some examples, the non-RT RIC 215 or the near-RT RIC 225 may be configured to tune RAN behavior or performance. For example, the non-RT RIC 215 may monitor long-term trends and patterns in performance and employ AI / ML models to perform corrective actions through the SMO framework 205 (such as via reconfiguration of O1) or by creating RAN management policies (such as A1 policies).

[0052] In one example, as described herein, BS communication component 442 can be implemented at least partially within CU 210 and can send one or more alignment parameters to one or more DUs 230. In this example, one or more DUs 230 can configure alignment parameters for UE 104 for receiving transmit bursts in CDRX mode. In another example, as described herein, BS communication component 442 can be implemented at least partially within DU 230 and can send one or more alignment parameters to one or more RUs 240. In this example, one or more RUs 240 can configure alignment parameters for UE 104 for receiving transmit bursts in CDRX mode.

[0053] Now turn Figures 3 to 8 , various aspects are described with reference to one or more components and one or more methods that can perform the actions or operations described herein, where aspects in dashed lines may be optional. Figure 5 and Figure 6 The operations described in the foregoing are presented in a particular order and / or as being performed by example components, but it should be understood that the order of these actions and the components performing the actions may vary depending on the specific implementation. Furthermore, it should be understood that the following actions, functions, and / or components described may be performed by a specially programmed processor, a processor executing specially programmed software or computer-readable media, or any other combination of hardware components and / or software components capable of performing the described actions or functions.

[0054] refer to Figure 3, in accordance with aspects described herein, an example implementation of the UE 104 may include a variety of components, some of which are described above and further described herein, including components such as one or more processors 312 and memory 316 in communication via one or more buses 344 and a transceiver 302, which may operate in conjunction with a modem 340 and / or a UE communication component 342 to manage configuration of a number of TCI states for a CJT using multiple TRPs, up to a maximum number.

[0055] In one aspect, the one or more processors 312 may include the modem 340 and / or may be part of the modem 340 using one or more modem processors. Thus, various functions associated with the UE communication components 342 may be included in the modem 340 and / or the processor 312 and, in one aspect, may be performed by a single processor, while in other aspects, different ones of these functions may be performed by a combination of two or more different processors. For example, in one aspect, the one or more processors 312 may include a modem processor, or a baseband processor, or a digital signal processor, or a transmit processor, or a receiver processor, or any one or any combination thereof, of a transceiver processor associated with the transceiver 302. In other aspects, some of the features of the one or more processors 312 and / or the modem 340 associated with the UE communication components 342 may be performed by the transceiver 302.

[0056] In addition, the memory 316 can be configured to store local versions of data and / or applications 375 used herein, or one or more of the UE communication component 342 and / or its subcomponents executed by the at least one processor 312. The memory 316 may include any type of computer-readable medium usable by a computer or the at least one processor 312, such as random access memory (RAM), read-only memory (ROM), tape, magnetic disk, optical disk, volatile memory, non-volatile memory, and any combination thereof. In one aspect, for example, when the UE 104 is operating the at least one processor 312 to execute one or more of the UE communication component 342 and / or its subcomponents, the memory 316 may be a non-transitory computer-readable storage medium that stores one or more computer-executable codes and / or data associated therewith that define the UE communication component 342 and / or its subcomponents.

[0057] The transceiver 302 may include at least one receiver 306 and at least one transmitter 308. The receiver 306 may include hardware, firmware, and / or software code executable by a processor, including instructions, and stored in memory (e.g., a computer-readable medium), for receiving data. The receiver 306 may be, for example, a radio frequency (RF) receiver. In one aspect, the receiver 306 may receive signals transmitted by at least one base station 102. Additionally, the receiver 306 may process such received signals and may also obtain measurements of these signals, such as, but not limited to, Ec / Io, signal-to-noise ratio (SNR), reference signal received power (RSRP), reference signal received quality (RSRQ), received signal strength indicator (RSSI), and the like. The transmitter 308 may include hardware, firmware, and / or software code executable by a processor, including instructions, and stored in memory (e.g., a computer-readable medium), for transmitting data. Suitable examples of the transmitter 308 may include, but are not limited to, an RF transmitter.

[0058] Furthermore, in an aspect, the UE 104 may include an RF front end 388 that may operate in communication with the one or more antennas 365 and the transceiver 302 to receive and transmit radio transmissions, e.g., wireless communications transmitted by at least one base station 102 or wireless transmissions transmitted by the UE 104. The RF front end 388 may be connected to the one or more antennas 365 and may include one or more low noise amplifiers (LNAs) 390, one or more switches 392, one or more power amplifiers (PAs) 398, and one or more filters 396 for transmitting and receiving RF signals.

[0059] In one aspect, the LNAs 390 can amplify the received signal to a desired output level. In one aspect, each LNA 390 can have a specified minimum gain value and a maximum gain value. In one aspect, the RF front end 388 can use one or more switches 392 to select a particular LNA 390 and its specified gain value based on the desired gain value for a particular application.

[0060] Furthermore, for example, the RF front end 388 can use one or more PAs 398 to amplify the signal for RF output at a desired output power level. In one aspect, each PA 398 can have a specified minimum gain value and a maximum gain value. In one aspect, the RF front end 388 can use one or more switches 392 to select a particular PA 398 and its specified gain value based on the desired gain value for a particular application.

[0061] Additionally, for example, the RF front end 388 can use one or more filters 396 to filter the received signal to obtain an input RF signal. Similarly, in one aspect, for example, the output from the corresponding PA 398 can be filtered using a corresponding filter 396 to produce an output signal for transmission. In one aspect, each filter 396 can be connected to a specific LNA 390 and / or PA 398. In one aspect, the RF front end 388 can use one or more switches 392 to select a transmit path or a receive path using a specific filter 396, LNA 390, and / or PA 398 based on a configuration specified by the transceiver 302 and / or the processor 312.

[0062] Thus, the transceiver 302 can be configured to transmit and receive wireless signals via the RF front end 388 through one or more antennas 365. In one aspect, the transceiver can be tuned to operate at a specified frequency so that the UE 104 can communicate with, for example, one or more base stations 102 or one or more cells associated with one or more base stations 102. In one aspect, for example, the modem 340 can configure the transceiver 302 to operate at a specified frequency and power level based on the UE configuration of the UE 104 and the communication protocol used by the modem 340.

[0063] In one aspect, the modem 340 may be a multi-band, multi-mode modem that can process digital data and communicate with the transceiver 302, enabling the digital data to be transmitted and received using the transceiver 302. In one aspect, the modem 340 may be multi-band and configured to support multiple frequency bands for a particular communication protocol. In one aspect, the modem 340 may be multi-mode and configured to support multiple operating networks and communication protocols. In one aspect, the modem 340 may control one or more components of the UE 104 (e.g., the RF front end 388, the transceiver 302) to enable the transmission and / or reception of signals from the network based on a specified modem configuration. In one aspect, the modem configuration may be based on the modem's mode and the frequency bands used. In another aspect, the modem configuration may be based on UE configuration information associated with the UE 104, such as provided by the network during cell selection and / or cell reselection.

[0064] In one aspect, in accordance with aspects described herein, the UE communication component 342 may optionally include: a capability indication component 352 for indicating the capability of the maximum number of active TCI states supported by multiple TRPs for CJT at the UE 104; a TCI state component 354 for receiving and / or managing the configuration of one or more TCI states corresponding to the multiple TRPs; and / or a spectrum derivation component 356 for deriving a PDP or Doppler spectrum based on a reference signal received in the configuration for one or more TCI states or otherwise indicated for receiving downlink data signals from a network node.

[0065] In one aspect, processor 312 may correspond to Figure 8 Similarly, the memory 316 may correspond to one or more processors in conjunction with the UE described in the embodiment of the present invention. Figure 8 The memory described by the UE in.

[0066] refer to Figure 4 In accordance with various aspects described herein, one example implementation of a base station 102 (e.g., base station 102 and / or gNB 180 as described above) may include various components, some of which have been described above, but include components such as one or more processors 412 and memory 416 communicating via one or more buses 444, and a transceiver 402, which may operate in conjunction with a modem 440 and a BS communication component 442 to configure a number of TCI states for a UE for CJT using multiple TRPs, up to a maximum number.

[0067] The transceiver 402, receiver 406, transmitter 408, one or more processors 412, memory 416, applications 475, bus 444, RF front end 488, LNA 490, switch 492, filter 496, PA 498, and one or more antennas 465 may be the same as or similar to the corresponding components of the UE 104 described above, but configured or otherwise programmed for base station operation rather than UE operation.

[0068] In one aspect, according to aspects described herein, the BS communication component 442 may optionally include: a capability determination component 452 for determining the UE capability for a maximum number of active TCI states supported for CJT from multiple TRPs; a TCI state configuration component 454 for configuring the TCI state for possible activation or otherwise indicating one or more TCI states for use by the UE 104 when receiving downlink data signals from the base station 102; and / or a reference signal (RS) component 456 for sending one or more RSs to facilitate derivation of a PDP or Doppler spectrum for channel estimation based on one or more TCI states.

[0069] In one aspect, processor 412 may correspond to Figure 8 Similarly, the memory 416 may correspond to one or more processors in conjunction with the base station described in the embodiment of the present invention. Figure 8 The memory described in the base station.

[0070] Figure 5 A flow chart illustrating an example of a method 500 for using or managing configuration of multiple TCI states for CJTs from multiple TRPs in accordance with aspects described herein. Figure 6 A flow chart illustrating an example of a method 600 for configuring a UE to use or manage multiple TCI states from a CJT for multiple TRPs in accordance with various aspects described herein. In one example, a UE 104 may use Figure 1 and Figure 3 One or more of the components described in the method 500 may be used to perform the functions described in the method 500, and a network node (such as a base station 102 or gNB, a portion of a decomposed base station 102 or gNB, etc.) may use Figure 1 and Figure 4 One or more of the components described in the method 600 may be used to perform the functions described in the method 600. Although the methods 500 and 600 are described in conjunction with each other for ease of explanation, these methods need not be performed in conjunction, and different devices may or may be configured to independently perform different methods.

[0071] In method 600, at block 602, an indication of one or more TCI states for CJT from at least a portion of a plurality of TRPs may be sent to a UE and based on a maximum number of TCI states. In one aspect, a TCI state configuration component 454 (e.g., in conjunction with processor 412, memory 416, transceiver 402, BS communication component 442, etc.) may send an indication of one or more TCI states for CJT from at least a portion of a plurality of TRPs to a UE (e.g., UE 104) and based on the maximum number of TCI states. For example, UE 104 may be configured to receive downlink data signals from a plurality of TRPs using CJT. UE 104 may be configured to receive downlink data signals from a maximum number N of TRPs (e.g., 4 TRPs in 5G NR), and a network node may select the number of TRPs for sending downlink data signals to UE 104 using CJT. In one example, the network node can select a number M of TRPs for CJT of downlink data signals to the UE 104, where M ≤ N. Each TRP and / or combination of TRPs used for CJT can be associated with multiple TCI states, and thus the number of TCI states that can be configured for the UE 104 can be large. Accordingly, the TCI state configuration component 454 can indicate or configure a reduced number of TCI states for the multiple TRPs (e.g., not exceeding a maximum number of active TCI states supported by the UE 104 for CJT using multiple TRPs). For example, the TCI state configuration component 454 can indicate one or more TCI states using RRC signaling, a media access control (MAC)-control element (CE), downlink control information (DCI) for a downlink data signal to be sent to the UE 104 (e.g., via a downlink channel such as a physical downlink shared channel (PDSCH)), etc.

[0072] In method 500, at block 502, an indication of one or more TCI states for a CJT from at least a portion of a plurality of TRPs may be received based on a maximum number of TCI states. In one aspect, TCI state component 354 (e.g., in conjunction with processor 312, memory 316, transceiver 302, UE communication component 342, etc.) may receive an indication of one or more TCI states for a CJT from at least the portion of the plurality of TRPs based on the maximum number of TCI states. For example, as described, TCI state component 354 may receive an indication of one or more TCI states from a network node in a MAC-CE, a DCI for a downlink data signal, or the like. In one example, the indicated TCI state may be selected from a plurality of configured TCI states, as further described herein. Thus, in one example, TCI state component 354 may receive the indication of the one or more TCI states as an index into a set of configured TCI states. Additionally, for example, the one or more TCI states may include a number of TCI states that is no greater than the maximum number of TCI states supported by UE 104. In this regard, by specifying a maximum number of TCI states, the UE 104 may manage a total number of TCI states that is less than the total number of all TRPs and / or the combination of multiple TRPs, which may reduce the processing burden of managing the TCI loop.

[0073] In one example, the maximum number of active TCI states supported by the UE 104 for CJT using multiple TRPs may be specified by a wireless communication technology standard (e.g., 5G NR) and may be known or stored in the memory 416 of the network node accordingly. In another example, the UE 104 may indicate the maximum number of supported active TCI states in UE capability information (e.g., in RRC signaling). In the method 600, optionally at block 604, a UE capability may be received for the UE, the UE capability indicating the maximum number of active TCI states or the maximum number of TCI state combinations supported for CJT from multiple TRPs. In one aspect, the capability determination component 452 (e.g., in conjunction with the processor 412, the memory 416, the transceiver 402, the BS communication component 442, etc.) may receive a UE capability for the UE (e.g., the UE 104), the UE capability indicating the maximum number of active TCI states or the maximum number of TCI state combinations supported for CJT from multiple TRPs. Similarly, in method 500, optionally at block 504, a UE capability may be sent that indicates a maximum number of active TCI states or a maximum number of TCI state combinations supported for CJT from multiple TRPs. In one aspect, capability indication component 352 (e.g., in conjunction with processor 312, memory 316, transceiver 302, UE communication component 342, etc.) may send a UE capability that indicates a maximum number of active TCI states or a maximum number of TCI state combinations supported for CJT from multiple TRPs. In one example, capability indication component 352 may send the UE capability indication in RRC signaling, and / or capability determination component 452 may receive the UE capability indication in RRC signaling. In one example, the capability for the maximum number K of UE active TCI states may be less than the UE capability for the maximum number N of TRPs for DL ​​CJT operation.

[0074] In one example, the UE capability may additionally or alternatively indicate a maximum number X of TCI state combinations or TRP combinations supported by the UE 104. For example, without this capability, it may be assumed that the UE supports all possible TRP combinations for CJT in the K TCI states (e.g., X for CJT). max =2 k -1 TRP combination). In another example, where X <X max Instructed by UE 104, the network node may configure the CJT to UE 104 TRP combination.

[0075] In one example, in method 500, optionally at block 506, a TCI state loop operation can be performed. In one aspect, UE communication component 342 (e.g., in conjunction with processor 312, memory 316, transceiver 302, etc.) can perform a TCI state loop operation (e.g., a tracking loop operation), which can include receiving an RS corresponding to a configured TCI state (e.g., as further described herein) and deriving a PDP or Doppler for the TCI state. In one example, spectrum derivation component 356 can generate a spectrum for CJT. In this example, capability indicating component 352 can indicate UE capability as the number of TCI states and the number of TRP combinations for CJT (eg, K=4 TCI states and X=6 TRP combinations).

[0076] In another example, the UE capabilities may additionally or alternatively indicate an {M, X} tuple, i.e., {number of TCI states, M, maximum supported number of TRP combinations for CJT, X, with M TCI states}. For example, the UE capabilities may indicate K=4 TCI states, and [{m=1, X=2}, {m=2, x=2}, {m=3, X=2}, {m=4x=1}]. In the above example, the TCI state configuration component 454 may use the indication of the number of supported TRP combinations for CJT to generate a TCI state configuration, select a portion of multiple TRPs, or select TCI states for multiple TRPs, as further described herein. For example, the TCI state configuration component 454 may generate a TCI state configuration having a number of TRP combinations that does not exceed the indicated maximum value or adheres to the maximum value indicated in the tuple for each TCI state. In another example, the TCI state configuration component 454 can select portions of the plurality of TRPs (e.g., in block 606) or various combinations of the plurality of TRPs so as not to exceed an indicated maximum value or to comply with a maximum value indicated in a tuple for each TCI state. In another example, the TCI state configuration component 454 can select TCI states (e.g., in block 608) so as not to exceed an indicated maximum value or to comply with a maximum value indicated in a tuple for each TCI state.

[0077] In method 600, optionally at block 606, a TCI state configuration indicating a plurality of TCI states for a plurality of TRPs may be sent to the UE and based on a maximum number of TCI states. In one aspect, TCI state configuration component 454 (e.g., in conjunction with processor 412, memory 416, transceiver 402, BS communication component 442, etc.) may send a TCI state configuration indicating a plurality of TCI states for a plurality of TRPs to a UE (e.g., UE 104) and based on the maximum number of TCI states. In one example, where a network node may activate or indicate one single frequency network (SFN) TCI state associated with a selected number M of TRPs, TCI state configuration component 454 may configure a TCI state pool, wherein the TCI states in the pool may be associated with 1≤M. k ≤N TRPs are associated, where M k is the number of SSBs from the selected TRP, one for each TRP. In another example, where the network node can activate or indicate a per-TRP TCI state, the TCI state configuration component 454 can configure a separate TCI state for each individual TRP in the plurality of TRPs (e.g., one TCI state for each of the N TRPs). In another example, where the network node can activate or indicate a per-TRP group TCI state (e.g., by grouping multiple TRPs together to have a single TCI state), the TCI state configuration component 454 can configure a separate TCI state for at least one TRP group and / or one or more individual TRPs in the plurality of TRPs.

[0078] In method 500, optionally at block 508, a TCI state configuration can be received that indicates a plurality of TCI states for a plurality of TRPs based on a maximum number of TCI states. In one aspect, TCI state configuration component 454 (e.g., in conjunction with processor 412, memory 416, transceiver 402, BS communication component 442, etc.) can receive a TCI state configuration that indicates a plurality of TCI states for a plurality of TRPs based on a maximum number of TCI states. For example, the TCI state configuration can be configured as described above and as further described herein, and can indicate a number of TCI states that does not exceed a maximum number of TCI states supported by UE 104. In one example, receiving the indication at block 502 can include receiving the indication as an index to one or more TCI states specified in the TCI state configuration, as described.

[0079] In method 600, optionally at block 608, at least the portion of the plurality of TRPs can be selected for transmitting downlink data signals to the UE. In one aspect, TCI state configuration component 454 (e.g., in conjunction with processor 412, memory 416, transceiver 402, BS communication component 442, etc.) can select at least the portion of the plurality of TRPs for transmitting downlink data signals to the UE. In one example, TCI state configuration component 454 can select at least the portion of TRPs (M) out of a plurality of TRPs (N) for transmitting downlink data signals to UE 104, where M≤N. Additionally, in method 600, optionally at block 610, one or more TCI states can be selected to include a plurality of TCI states, up to a maximum number of active TCI states supported for the plurality of TRPs. In one aspect, TCI state configuration component 454 (e.g., in conjunction with processor 412, memory 416, transceiver 402, BS communication component 442, etc.) can select one or more TCI states to include a plurality of TCI states, up to a maximum number of active TCI states supported for a plurality of TRPs. In one example, the one or more selected TCI states can correspond to a selected portion of a plurality of TRPs. Additionally, for example, the indication sent at block 602 and / or received at block 502 can be based on the one or more selected TCI states associated with the selected portion of a plurality of TRPs.

[0080] In one example described above, where the network node can activate or indicate an SFN TCI state associated with a selected number M of TRPs, the TCI state configuring component 454 can select at least the portion M of the plurality of TRPs and activate an SFN TCI state for the portion of the plurality of TRPs. In this example, the SFN TCI state TCI k Available with M from selected TRP k Synchronization signal blocks (SSB) are quasi-co-located (QCL), with one synchronization signal block per TRP. For example, In one example, as further described herein, RS component 456 can select a TRP (e.g., as ) sends a downlink reference signal (e.g., a tracking reference signal (TRS)).

[0081] In another example described above, where the network node can activate or indicate a per-TRP TCI state for a plurality of TRPs CJTs, the TCI state configuration component 454 can select at least the portion M of the plurality of TRPs. In this example, the TCI state configuration component 454 can activate or indicate a per-TRP TCI state associated with each TRP in the selected portion of the plurality of TRPs.

[0082] In another example described above, where the network node can activate or indicate at least one TCI state for a TRP group (e.g., a per-TRP group TCI state), the TCI state configuration component 454 can select at least the portion M of the plurality of TRPs. In this example, the TCI state configuration component 454 can activate or indicate at least one per-TRP group TCI state and / or one or more additional per-TRP group TCI states or per-TRP TCI states for ungrouped TRPs. In this example, due to the TRP grouping used for TCI state construction, multiple TRPs can be associated with one TCI state. In one example, the BS communication component 442 can determine to group the TRPs for the purpose of sharing the TCI state. For example, the BS communication component 442 can group two or more TRPs from the plurality of TRPs based on the timing or frequency error between the TRPs being less than a threshold. In any case, grouping the TRPs for the purpose of TCI state configuration or management can further reduce the number of TCI states configured for the UE 104.

[0083] In the method 600, at block 612, one or more downlink RSs may be sent from at least the portion of the plurality of TRPs based on the indication. In one aspect, the RS component 456 (e.g., in conjunction with the processor 412, the memory 416, the transceiver 402, the BS communication component 442, etc.) may send one or more downlink RSs from at least the portion of the selected plurality of TRPs (e.g., at block 608) based on the indication of the one or more TCI states. For example, the downlink RSs may include TRSs, SSBs, CSI-RSs, SRSs, etc., and may be sent based on each of the one or more TCI states corresponding to the selected portion of the plurality of TRPs.

[0084] In the method 500, at block 510, one or more downlink RSs may be received from at least a portion of the TRPs based on the indication. In one aspect, the UE communication component 342 (e.g., in conjunction with the processor 312, the memory 316, the transceiver 302, etc.) may receive one or more downlink RSs from at least a portion of the selected plurality of TRPs (e.g., at block 608) based on the indication of the one or more TCI states. For example, the downlink RSs may include TRSs, SSBs, CSI-RSs, SRSs, etc., and may be received based on each of the one or more TCI states corresponding to the selected portion of the plurality of TRPs.

[0085] In method 500, at block 512, a PDP or Doppler spectrum for channel estimation for at least a portion of one or more TCI states may be derived based on one or more downlink RSs. In one aspect, spectrum deriving component 356 (e.g., in conjunction with processor 312, memory 316, transceiver 302, UE communication component 342, etc.) may derive a PDP or Doppler spectrum for channel estimation for at least a portion of one or more TCI states based on one or more downlink RSs.

[0086] In one of the above examples, where the network node may activate or indicate an SFN TCI state associated with the selected M number of TRPs, the RS component 456 may send one or more downlink RSs based on an SFN TCI state associated with the selected M number of TRPs (e.g., in an SFN manner from the selected TRPs), and the UE communication component 342 may receive one or more downlink RSs based on an SFN TCI state associated with the configuration of the selected M number of TRPs. In this example, the spectrum derivation component 356 may use the DL reference RS for the SFN TCI state and / or may derive PDP or Doppler for channel estimation from measurements of the SFN RS. Figure 7 An example is shown in .

[0087] Figure 7 Examples of PDP spectra 700, 702, 704, 706 derived for various TRP or TCI state configurations are illustrated. In PDP spectrum 700, TRP0, TRP1, and TRP2 transmit downlink RSs as SFN RSs, and spectrum deriving component 356 can derive a PDP or Doppler spectrum of the combined SFN RSs as received for the SFN TCI state.

[0088] In another example described above, where the network node can activate or indicate a TCI state for each of the plurality of TRPs CJT, the RS component 456 can transmit one or more downlink RSs separately from each of the selected number M of TRPs, and the UE communication component 342 can receive downlink RSs separately from each of the selected number M of TRPs. In this example, the spectrum deriving component 356 can derive a combined PDP or Doppler spectrum, such as Figure 7 shown.

[0089] In this example, UE communication component 342 can receive a downlink RS for TCI0, and spectrum deriving component 356 can derive a PDP or Doppler spectrum at 702. UE communication component 342 can also receive a downlink RS for TCI1, and spectrum deriving component 356 can derive a PDP or Doppler spectrum at 704. In this example, spectrum deriving component 356 can combine the derived PDP or Doppler spectra to derive a combined PDP or Doppler spectrum at 706.

[0090] In this regard, for example, when deriving the PDP or Doppler spectrum at block 512, the combined PDP or Doppler spectrum can be derived based on combining the derived PDP or Doppler spectrum for each of the plurality of TCI states, optionally at block 514. In one aspect, spectrum deriving component 356 (e.g., in conjunction with processor 312, memory 316, transceiver 302, UE communication component 342, etc.) can derive the combined PDP or Doppler spectrum based on combining the derived PDP or Doppler spectrum for each of the plurality of TCI states (e.g., as derived for each of the plurality of RSs received corresponding to the plurality of TCI states).

[0091] In another example described above, where the network node may activate or indicate at least one TCI state for a TRP group (e.g., a TCI state per TRP group), the RS component 456 may send a downlink RS associated with the TCI state for the TRP group as a QCL reference for multiple TRPs in the group. In one example, the RS component 456 may send a downlink RS from one TRP in the group as a QCL reference. In another example, the RS component 456 may send a downlink RS from all (or multiple) TRPs in the group in an SFN manner as a QCL reference. In either example, the UE communication component 342 may receive the downlink RS, and the spectrum derivation component 356 may use the downlink RS to derive a PDP or Doppler spectrum for the TCI state for the TRP group. In this example, the RS component 456 may send additional RSs for other per-TRP or per-TRP group TCI states and the UE communication component 342 may receive additional RSs for other per-TRP or per-TRP group TCI states, and the spectrum derivation component 356 may use the downlink RSs to derive the PDP or Doppler spectrum for the associated TCI states.

[0092] In one example, deriving the PDP and Doppler spectrum can enable the UE (e.g., via the UE communication component 342) to perform channel estimation for a downlink data signal that can be received from a network node based on a DCI or other schedule. As described, in one example, the DCI can indicate a TCI state (e.g., one or more TCI states) for transmitting the downlink data signal or a TCI state associated with a plurality of TRPs for transmitting the downlink data signal. Thus, the spectrum deriving component 356 can derive the PDP or Doppler spectrum of the associated downlink RS received for the downlink data signal in order to perform channel estimation for the downlink data signal.

[0093] In one example, a certain TRP or combination of TRPs may have a timing or frequency (or other synchronization) difference exceeding a threshold from the UE 104 or a TRP, and thus the CJT from such a TRP or combination of TRPs may have a timing or frequency (or other synchronization) error exceeding a threshold or otherwise degrading downlink performance. Thus, in some examples, an undesirable TRP or combination of TRPs or associated TCI states may be reported to the network node. For example, the UE 104 may detect such a TRP or combination of TRPs based on detecting that a PDP or Doppler spread associated with a certain TCI state exceeds (or satisfies) a threshold.

[0094] Thus, in method 500, optionally at block 516, an indication of at least one of the one or more TCI states associated with one downlink RS having a PDP or Doppler spread that achieves a threshold value may be reported. In one aspect, spectrum deriving component 356 (e.g., in conjunction with processor 312, memory 316, transceiver 302, UE communication component 342, etc.) may report (e.g., to a network node) an indication of at least one of the one or more TCI states associated with one downlink RS having a PDP or Doppler spread that achieves a threshold value from one of the one or more downlink RSs. For example, spectrum deriving component 356 may compare the spectrum derived for the TCI state (e.g., at blocks 512 or 514) with a threshold value and may report the TCI state to the network node if the PDP or Doppler spread of the TCI state exceeds (or meets) the threshold value. For example, UE 104 may be configured with the threshold value by the network node, via instructions in memory 316, based on a wireless communication technology standard, etc. In another example, the spectrum derivation component 356 can compare the derived spectra for a TCI state pair (or other multiple TCI states) (e.g., at blocks 512 or 514) and can report the TCI state pair to a network node if a difference between the PDP or Doppler spread of the TCI state pair exceeds (or meets) a threshold.

[0095] In addition, in one example, spectrum derivation component 356 can report TCI states or TCI state pairs using uplink control channel signaling, RRC, or other static or semi-static signaling. In one example, spectrum derivation component 356 can report an indication of multiple TRPs in the FDD band in the CSI feedback. In a specific example, when selecting TCI states for CJT CSI feedback, spectrum derivation component 356 can deprioritize such TCI states (e.g., TCI states associated with a TRP or a combination of TRPs or TCI state pairs with large timing or frequency errors). Deprioritization can indicate that the TCI state has an undesirable PDP or Doppler spread.

[0096] In method 600, at block 614, an indication of at least one of one or more TCI states associated with one of one or more downlink RSs having a PDP or Doppler spread that achieves a threshold value may be received from a UE. In one aspect, TCI state configuration component 454 (e.g., in conjunction with processor 412, memory 416, transceiver 402, BS communication component 442, etc.) may receive an indication of at least one of one or more TCI states associated with one of one or more downlink RSs having a PDP or Doppler spread that achieves a threshold value from a UE (e.g., UE 104). In one example, TCI state configuration component 454 may use the indication to identify a TCI state associated with a TRP or combination of TRPs having a large intra-group timing or frequency error, and may accordingly avoid using the TRP or associating a combination of TRPs in a group for CJT to UE 104 and / or associating subsequent CJT to one or more other UEs. In another example, TCI state configuring component 454 can use the indication to identify a pair (or other plurality) of TCI states having a large intra-group timing or frequency difference therebetween, and can accordingly refrain from configuring or activating these TCI states for CJT to UE 104 and / or subsequent CJT to one or more other UEs.

[0097] In method 600, at block 616, at least one of the one or more TCI states or an associated TRP may be avoided in a subsequent CJT to the UE or one or more other UEs. In one aspect, TCI state configuration component 454 (e.g., in conjunction with processor 412, memory 416, transceiver 402, BS communication component 442, etc.) may avoid at least one of the one or more TCI states or an associated TRP in a subsequent CJT to the UE or one or more other UEs. For example, TCI state configuration component 454 may avoid a reported combination of TCI states and / or associated TRPs when selecting at least a portion of a plurality of TRPs at block 608 and / or when selecting one or more TCI states at block 610.

[0098] Figure 8 1 is a block diagram of a MIMO communication system 800 including a base station 102 and a UE 104. The MIMO communication system 800 may be exemplified with reference to Figure 1 Aspects of the wireless communication access network 100 are described. The base station 102 may be a reference Figure 1 8. Examples of various aspects of base station 102 are described. Base station 102 may be equipped with antenna 834 and antenna 835, and UE 104 may be equipped with antenna 852 and antenna 853. In MIMO communication system 800, base station 102 may be able to transmit data simultaneously over multiple communication links. Each communication link may be referred to as a "layer," and the "rank" of a communication link may indicate the number of layers used for communication. For example, in a 2x2 MIMO communication system in which base station 102 transmits two "layers," the rank of the communication link between base station 102 and UE 104 is two.

[0099] At the base station 102, a transmit (Tx) processor 820 may receive data from a data source. The transmit processor 820 may process the data. The transmit processor 820 may also generate control symbols or reference symbols. The transmit MIMO processor 830 may perform spatial processing (e.g., precoding) on ​​the data symbols, control symbols, or reference symbols (if applicable) and may provide output symbol streams to transmit modulators / demodulators 832 and 833. Each modulator / demodulator 832 to 833 may process a corresponding output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator / demodulator 832 to 833 may further process the output sample stream (e.g., convert the output sample stream to analog, amplify, filter, and upconvert) to obtain a DL signal. In one example, the DL signals from the modulator / demodulator 832 and 833 may be transmitted via antenna 834 and antenna 835, respectively.

[0100] UE 104 may be a reference Figure 1 and Figure 3104. UE 104 may be configured to receive DL signals from base station 102 using antenna 852 and antenna 853, respectively. Each modulator / demodulator 854-855 may condition a respective received signal (e.g., filter, amplify, downconvert, and digitize the respective received signal) to obtain input samples. Each modulator / demodulator 854-855 may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector 856 may obtain received symbols from modulators / demodulators 854-855, perform MIMO detection on the received symbols (if applicable), and provide detected symbols. A receive (Rx) processor 858 may process (eg, demodulate, deinterleave, and decode) the detected symbols to provide decoded data for the UE 104 to a data output and provide decoded control information to a processor 880 or memory 882 .

[0101] In some cases, processor 880 may execute stored instructions to instantiate UE communication component 342 (see, e.g., Figure 1 and Figure 3 ).

[0102] On the uplink (UL), at UE 104, a transmit processor 864 may receive and process data from a data source. The transmit processor 864 may also generate reference symbols for reference signals. The symbols from transmit processor 864 may be pre-decoded by a transmit MIMO processor 866 (if applicable), further processed by modulators / demodulators 854 and 855 (e.g., for single-carrier FDMA, etc.), and transmitted to base station 102 based on communication parameters received from base station 102. At base station 102, the UL signals from UE 104 may be received by antennas 834 and 835, processed by modulators / demodulators 832 and 833, detected by a MIMO detector 836 (if applicable), and further processed by a receive processor 838. The receive processor 838 may provide decoded data to a data output and to processor 840 or memory 842.

[0103] In some cases, processor 840 may execute stored instructions to instantiate BS communication component 442 (see, e.g., Figure 1 and Figure 4 ).

[0104] The components of UE 104 may be implemented individually or collectively using one or more ASICs adapted to perform some or all of the applicable functions in hardware. Each of the modules indicated may be a means for performing one or more functions associated with the operation of MIMO communication system 800. Similarly, the components of base station 102 may be implemented individually or collectively using one or more application-specific integrated circuits (ASICs) adapted to perform some or all of the applicable functions in hardware. Each of the components indicated may be a means for performing one or more functions associated with the operation of MIMO communication system 800.

[0105] The following aspects are merely illustrative, and aspects thereof may be combined with aspects of other embodiments or teachings described herein without limitation.

[0106] Aspect 1 is a method for wireless communication at a UE, the method comprising: sending UE capabilities to a network node, the UE capabilities indicating a maximum number of active TCI states supported for CJTs from multiple TRPs; receiving, from the network node and based on the maximum number of TCI states, an indication of one or more TCI states for CJTs from at least a portion of the multiple TRPs; receiving one or more downlink reference signals from at least the portion of the multiple TRPs based on the indication; and deriving a PDP or Doppler spectrum for channel estimation for at least a portion of the one or more TCI states based on the one or more downlink reference signals.

[0107] In aspect 2, the method according to aspect 1 includes wherein the indication is received in DCI, MAC-CE signaling, or RRC signaling.

[0108] In aspect 3, the method according to any one of aspects 1 or 2 includes wherein the indication includes a TCI state for at least the portion of the plurality of TRPs including two or more TRPs from the plurality of TRPs.

[0109] In aspect 4, the method according to aspect 3 includes wherein the one TCI state is quasi-co-located with a downlink reference signal from each TRP in the portion of the plurality of TRPs.

[0110] In aspect 5, the method according to any one of aspects 3 or 4 includes receiving a TCI state configuration specifying a TCI state pool from the network node and based on the maximum number of TCI states, each TCI state being associated with a combination of at least a portion of the multiple TRPs, wherein the indication of the one or more TCI states corresponds to the TCI state configuration.

[0111] In aspect 6, the method according to any one of aspects 1 to 5 includes receiving a TCI state configuration from the network node and based on the maximum number of TCI states, the TCI state configuration specifying a TCI state for each TRP in a portion of the multiple TRPs including the one or more TCI states.

[0112] In aspect 7, the method according to aspect 6 includes performing a tracking loop operation for the one TCI state per TRP.

[0113] In aspect 8, the method according to any one of aspects 6 or 7 includes wherein the indication of one or more TCI states includes an indication of multiple TCI states, each TCI state corresponding to one of at least the portion of the multiple TRPs selected for CJT transmission, and wherein deriving the PDP or Doppler spectrum includes deriving a combined PDP or Doppler spectrum for receiving downlink data signals from at least the portion of the multiple TRPs selected for CJT transmission at least in part by combining the derived PDP or Doppler spectrum for each TCI state in the multiple TCI states.

[0114] In aspect 9, the method according to any one of aspects 1 to 8 includes receiving a TCI state configuration from the network node and based on the maximum number of TCI states, the TCI state configuration specifying a plurality of TCI states including the one or more TCI states, wherein the one or more TCI states include a TCI state for a TRP group including one or more TRPs from the plurality of TRPs.

[0115] In aspect 10, the method according to aspect 9 includes wherein the plurality of TCI states includes at least one other TCI state of another TRP group, the another TRP group including one or more other TRPs from the plurality of TRPs.

[0116] In aspect 11, the method according to any one of aspects 9 or 10 includes wherein the one TCI state for at least one TRP group is quasi-co-located with a downlink reference signal from each TRP in the at least one TRP group.

[0117] In aspect 12, the method according to any one of aspects 9 to 11 includes wherein the indication of one or more TCI states includes an indication of at least a portion of the multiple TCI states, the multiple TCI states including the one TCI state for the TRP group, and wherein deriving the PDP or Doppler spectrum includes deriving a combined PDP or Doppler spectrum for at least the portion of the received downlink data signals selected for CJT transmission from the multiple TRPs at least in part by combining the derived PDP or Doppler spectrum for each of the multiple TCI states including the one TCI state for the at least one TRP group.

[0118] In aspect 13, the method according to any one of aspects 1 to 12 includes wherein the maximum number of TCI states is less than the maximum number of TRPs for CJT transmission indicated in different UE capabilities.

[0119] In aspect 14, the method according to any one of aspects 1 to 13 includes wherein the UE capabilities further indicate a maximum number of supported TCI state combinations supported for CJT, and wherein the configuration is further based on the maximum number of supported TCI state combinations.

[0120] In aspect 15, the method according to aspect 14 includes wherein the UE capabilities further indicate one or more tuples of the number of TCI states and the maximum supported number of TCI state combinations and the number of TCI states, and wherein the configuration is based on the one or more tuples.

[0121] In aspect 16, the method according to any one of aspects 1 to 15 includes reporting to the network node a first indication of at least one of the one or more TCI states associated with one of the one or more downlink reference signals having a PDP extension or Doppler extension that achieves a threshold.

[0122] In aspect 17, the method according to any one of aspects 1 to 16 comprises reporting to the network node an indication of a TCI status pair associated with a downlink reference signal pair having a difference in PDP spread or Doppler spread that achieves a threshold.

[0123] In aspect 18, the method according to any one of aspects 1 to 17 includes: sending CSI feedback for the one or more TCI states to the network node; and deprioritizing the CSI feedback for a portion of the multiple TCI states associated with a downlink reference signal having a difference in PDP spread or Doppler spread that achieves a threshold in the one or more downlink reference signals.

[0124] Aspect 19 is a method for wireless communication at a network node, the method comprising: for a UE, receiving UE capabilities, the UE capabilities indicating a maximum number of active TCI states supported for CJTs from multiple TRPs; sending, to the UE and based on the maximum number of TCI states, an indication of one or more TCI states for CJTs from at least a portion of the multiple TRPs; and sending one or more downlink reference signals from at least the portion of the multiple TRPs based on the indication.

[0125] In aspect 20, the method of aspect 19 includes wherein the indication is sent in DCI, MAC-CE signaling, or RRC signaling.

[0126] In aspect 21, the method according to any one of aspects 19 or 20 includes wherein the indication includes a TCI state for at least the portion of the plurality of TRPs including two or more TRPs from the plurality of TRPs.

[0127] In aspect 22, the method according to aspect 21 includes wherein the one TCI state is quasi-co-located with a downlink reference signal from each TRP in the portion of the plurality of TRPs.

[0128] In aspect 23, the method according to aspect 22 includes wherein sending the one or more downlink reference signals from each TRP in the portion of the multiple TRPs includes sending the one or more downlink reference signals in an SFN manner.

[0129] In aspect 24, the method according to any one of aspects 21 or 23 includes sending a TCI state configuration specifying a TCI state pool to the UE and based on the maximum number of the TCI states, each TCI state being associated with a combination of at least a portion of the multiple TRPs, wherein the indication of the one or more TCI states corresponds to the TCI state configuration.

[0130] In aspect 25, the method according to any one of aspects 19 to 24 includes sending a TCI state configuration to the UE and based on the maximum number of TCI states, the TCI state configuration specifying one TCI state for each TRP of the multiple TRPs including the one or more TCI states.

[0131] In aspect 26, the method according to aspect 25 includes selecting at least a portion of the multiple TRPs for sending a downlink data signal to the UE, wherein the indication of one or more TCI states includes an indication of multiple TCI states, each TCI state corresponding to one of at least the portion of the multiple TRPs selected for CJT transmission.

[0132] In aspect 27, the method according to any one of aspects 19 to 26 includes sending a TCI state configuration to the UE and based on the maximum number of TCI states, the TCI state configuration specifying multiple TCI states including the one or more TCI states, wherein the one or more TCI states include a TCI state for a TRP group including one or more TRPs from the multiple TRPs.

[0133] In aspect 28, the method according to aspect 27 includes selecting at least the portion of the multiple TRPs including the TRP group for sending a downlink data signal to the UE, wherein the indication of one or more TCI states includes an indication of multiple TCI states, and the multiple TCI states include the at least one TCI state for the TRP group.

[0134] In aspect 29, the method according to any one of aspects 27 or 28 includes wherein the plurality of TCI states includes at least one other TCI state for another TRP group, the another TRP group including one or more other TRPs from the plurality of TRPs.

[0135] In aspect 30, the method according to any one of aspects 27 to 29 includes wherein the one TCI state for at least one TRP group is quasi-co-located with a downlink reference signal from each TRP in the at least one TRP group.

[0136] In aspect 31, the method according to any one of aspects 27 to 30 includes selecting at least a portion of the multiple TRPs for sending a downlink data signal to the UE, wherein the indication of one or more TCI states includes an indication of multiple TCI states, each TCI state corresponding to one of at least a portion of the multiple TRPs selected for CJT transmission.

[0137] In aspect 32, the method according to any one of aspects 19 to 31 includes wherein the maximum number of TCI states is less than the maximum number of TRPs for CJT transmission indicated in different UE capabilities.

[0138] In aspect 33, the method of aspect 32 includes selecting the one or more TCI states to include a maximum number of TCI states up to a maximum number of active TCI states for the TRP.

[0139] In aspect 34, the method according to any one of aspects 19 to 33 includes wherein the UE capabilities further indicate a maximum number of supported TCI state combinations supported for CJT, and wherein the configuration is further based on the maximum number of supported TCI state combinations.

[0140] In aspect 35, the method according to aspect 34 includes sending a configuration to the UE indicating the number of TCI state combinations to which the one or more TCI states correspond.

[0141] In aspect 36, the method according to any one of aspects 34 or 35 includes wherein the UE capabilities further indicate one or more tuples of the number of TCI states and the maximum supported number of TRP combinations and the number of TCI states, and wherein the configuration is based on the one or more tuples.

[0142] In aspect 37, the method according to any one of aspects 19 to 36 includes: receiving from the UE an indication of at least one of the one or more TCI states associated with one of the one or more downlink reference signals having a PDP extension or Doppler extension that achieves a threshold; and selecting a subset of at least the portion of the multiple TRPs for sending downlink data signals to the UE or one or more other UEs, including avoiding a combination of TRPs associated with the at least one TCI state of the one or more TCI states.

[0143] In aspect 38, the method according to any one of aspects 19 to 37 includes: receiving from the UE an indication of a TCI state pair associated with a downlink reference signal pair having a difference in PDP spread or Doppler spread that achieves a threshold; and selecting a subset of at least the portion of the multiple TRPs for sending downlink data signals to the UE or one or more other UEs, including avoiding TCI state pairs.

[0144] Aspect 39 is an apparatus for wireless communication, the apparatus comprising: a processor; a memory coupled to the processor; and instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to perform any of the methods described in aspects 1 to 38.

[0145] Aspect 40 is an apparatus for wireless communication, the apparatus comprising means for performing any of the methods described in aspects 1 to 38.

[0146] Aspect 41 is a computer-readable medium comprising code executable by one or more processors for wireless communication, the code comprising code for performing any of the methods according to aspects 1 to 38.

[0147] The above detailed descriptions set forth above in conjunction with the accompanying drawings describe examples and do not represent the only examples that can be implemented or fall within the scope of the claims. The term "example" as used in this specification means "serving as an example, instance, or illustration," rather than "preferred" or "having advantages over other examples." The detailed description includes specific details to provide an understanding of the described techniques. However, these techniques can be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described examples.

[0148] Information and signals may be represented using any of a variety of different technologies and techniques. For example, the data, instructions, commands, information, signals, bits, symbols, and chips mentioned in the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, computer executable code or instructions stored on a computer-readable medium, or any combination thereof.

[0149] The various illustrative blocks and components described in conjunction with the disclosure herein may be implemented or executed using a specially programmed device, such as, but not limited to, a processor for performing the functions described herein, a digital signal processor (DSP), an ASIC, a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof. Although the specially programmed processor may be a microprocessor, in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The specially programmed processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0150] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored as one or more instructions or codes on or transmitted via a non-transitory computer-readable medium. Other examples and specific implementations fall within the scope and spirit of this disclosure and the appended claims. For example, due to the nature of software, the functions described above may be implemented using hardware, firmware, hardwiring, software executed by a specially programmed processor, or a combination of any of these. Features implementing the functions may also be physically located at different locations, including being distributed so that the various parts of the functions are implemented at different physical locations. In addition, as used herein, including in the claims, "or" used in a list of items beginning with "at least one of" indicates a dispersed list, so that, for example, a list of "at least one of A, B, or C" means A or B or C or AB or AC or BC or ABC (i.e., A and B and C).

[0151] Computer-readable medium includes both computer storage media and communication media, including any medium that promotes a computer program to be transferred from one place to another. Storage medium can be any available medium that can be accessed by a general or special-purpose computer. By way of example and not limitation, computer-readable medium can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage devices, magnetic disk storage devices or other magnetic storage devices, or can be used for carrying or storing desired program code components and any other medium that can be accessed by a general or special-purpose computer or a general or special-purpose processor in the form of an instruction or data structure. In addition, any connection is suitably referred to as computer-readable medium. For example, if software is sent from a website, server or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) or wireless technologies such as infrared, radio and microwaves, then coaxial cable, fiber optic cable, twisted pair, DSL or wireless technologies such as infrared, radio and microwaves are included in the definition of medium. As used herein, disk and disc include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc, where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

[0152] The previous description of the present disclosure is provided to enable those skilled in the art to implement or use the present disclosure. Various modifications to the present disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the essence or scope of the present disclosure. Furthermore, although elements of the described aspects and / or embodiments are described or claimed in the singular, the plural form may also be envisioned unless expressly stated to be limited to the singular. Additionally, unless otherwise stated, all or part of any aspect and / or embodiment may be used together with all or part of any other aspect and / or embodiment. Therefore, the present disclosure is not limited to the examples and designs described herein, but should be granted the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A device for wireless communication, the device comprising: processor; a memory coupled to the processor; and instructions stored in the memory and operable when executed by the processor to cause the apparatus to: sending user equipment (UE) capabilities to a network node, the user equipment (UE) capabilities indicating a maximum number of active transmit configuration indicator (TCI) states supported for coherent joint transmission (CJT) from a plurality of transmit reception points (TRPs); receiving, from the network node and based on the maximum number of TCI states, an indication of one or more TCI states for CJTs from at least a portion of the plurality of TRPs; receiving one or more downlink reference signals from at least the portion of the plurality of TRPs based on the indication; as well as A power delay profile (PDP) or a Doppler spectrum for channel estimation for at least a portion of the one or more TCI states is derived based on the one or more downlink reference signals.

2. The apparatus of claim 1, wherein the indication is received in downlink control information (DCI), medium access control (MAC)-control element (CE) signaling, or radio resource configuration (RRC) signaling.

3. An apparatus according to claim 1, wherein the indication includes a TCI state for at least the portion of the multiple TRPs including two or more TRPs from the multiple TRPs.

4. An apparatus according to claim 3, wherein the one TCI state is quasi-co-located with a downlink reference signal from each TRP in the portion of the multiple TRPs.

5. The apparatus of claim 3, wherein the instructions, when executed by the processor, cause the apparatus to receive, from the network node and based on a maximum number of the TCI states, a TCI state configuration specifying a pool of TCI states, each TCI state being associated with a combination of at least a portion of the plurality of TRPs, wherein the indication of the one or more TCI states corresponds to the TCI state configuration.

6. The apparatus of claim 1 , wherein the instructions, when executed by the processor, cause the apparatus to receive a TCI state configuration from the network node and based on the maximum number of TCI states, the TCI state configuration specifying a TCI state for each TRP in a portion of the plurality of TRPs that include the one or more TCI states.

7. The apparatus of claim 6, wherein the instructions, when executed by the processor, cause the apparatus to perform a tracking loop operation for the one TCI state for each TRP.

8. The apparatus of claim 6, wherein the indication of one or more TCI states comprises an indication of a plurality of TCI states, each TCI state corresponding to one of at least the portion of the plurality of TRPs selected for CJT transmission, and Wherein the instructions, when executed by the processor, cause the apparatus to derive, at least in part, a combined PDP or Doppler spectrum for receiving at least the portion of downlink data signals selected for CJT transmission from the multiple TRPs by combining the derived PDP or Doppler spectrum for each of the multiple TCI states.

9. The apparatus of claim 1 , wherein the instructions, when executed by the processor, cause the apparatus to receive a TCI state configuration from the network node and based on the maximum number of TCI states, the TCI state configuration specifying a plurality of TCI states including the one or more TCI states, wherein the one or more TCI states include a TCI state for a TRP group including one or more TRPs from the plurality of TRPs.

10. The apparatus of claim 9, wherein the plurality of TCI states comprises at least one other TCI state of another TRP group, the another TRP group comprising one or more other TRPs from the plurality of TRPs.

11. The apparatus of claim 9, wherein the one TCI state for at least one TRP group is quasi-co-located with a downlink reference signal from each TRP in the at least one TRP group.

12. The apparatus of claim 9, wherein the indication of one or more TCI states comprises an indication of at least a portion of the plurality of TCI states, the plurality of TCI states including the one TCI state for the TRP group, and Wherein the instructions, when executed by the processor, cause the apparatus to derive, at least in part, a combined PDP or Doppler spectrum for receiving at least the portion of downlink data signals selected for CJT transmission from the multiple TRPs by combining the derived PDP or Doppler spectrum for each of the multiple TCI states including the one TCI state for the at least one TRP group.

13. The apparatus of claim 1, wherein the maximum number of TCI states is less than a maximum number of TRPs for CJT transmission indicated in different UE capabilities.

14. The apparatus of claim 1, wherein the UE capabilities further indicate a maximum number of supported TCI state combinations supported for CJT, and wherein the configuration is further based on the maximum number of supported TCI state combinations.

15. The apparatus of claim 14, wherein the UE capabilities further indicate one or more tuples of a number of TCI states and a maximum supported number of TCI state combinations and the number of TCI states, and wherein the configuration is based on the one or more tuples.

16. The apparatus of claim 1 , wherein the instructions, when executed by the processor, cause the apparatus to report to the network node a first indication of at least one of the one or more TCI states associated with one of the one or more downlink reference signals having a PDP extension or a Doppler extension that achieves a threshold.

17. The apparatus of claim 1, wherein the instructions, when executed by the processor, cause the apparatus to report to the network node an indication of a TCI state pair associated with a downlink reference signal pair having a difference in PDP spread or Doppler spread that achieves a threshold.

18. The apparatus of claim 1, wherein the instructions, when executed by the processor, cause the apparatus to: sending channel state information (CSI) feedback for the one or more TCI states to the network node; and The CSI feedback for a portion of a plurality of TCI states associated with one of the one or more downlink reference signals having a difference in PDP spreading or Doppler spreading that achieves a threshold is deprioritized.

19. An apparatus for wireless communication, the apparatus comprising: processor; a memory coupled to the processor; and instructions stored in the memory and operable when executed by the processor to cause the apparatus to: For a user equipment (UE), receiving UE capabilities indicating a maximum number of active transmit configuration indicator (TCI) states supported for coherent joint transmission (CJT) from a plurality of transmit receive points (TRPs); sending, to the UE and based on the maximum number of TCI states, an indication of one or more TCI states for a CJT from at least a portion of the plurality of TRPs; as well as One or more downlink reference signals are sent from at least a portion of the multiple TRPs based on the indication.

20. The apparatus of claim 19, wherein the indication is sent in downlink control information (DCI), medium access control (MAC)-control element (CE) signaling, or radio resource configuration (RRC) signaling.

21. The apparatus of claim 19, wherein the indication comprises a TCI state for at least the portion of the plurality of TRPs including two or more TRPs from the plurality of TRPs.

22. An apparatus according to claim 21, wherein the one TCI state is quasi-co-located with a downlink reference signal from each TRP in the portion of the multiple TRPs.

23. An apparatus according to claim 22, wherein the instructions, when executed by the processor, cause the apparatus to send the one or more downlink reference signals from each TRP in the portion of the multiple TRPs in a single frequency network (SFN) manner.

24. An apparatus according to claim 21, wherein the instructions, when executed by the processor, cause the apparatus to send a TCI state configuration of a specified TCI state pool to the UE and based on the maximum number of the TCI states, each TCI state is associated with a combination of at least a portion of the multiple TRPs, wherein the indication of the one or more TCI states corresponds to the TCI state configuration.

25. An apparatus according to claim 19, wherein the instructions, when executed by the processor, cause the apparatus to send a TCI state configuration to the UE and based on the maximum number of TCI states, the TCI state configuration specifying a TCI state for each TRP in the multiple TRPs including the one or more TCI states.

26. An apparatus according to claim 19, wherein the instructions, when executed by the processor, cause the apparatus to send a TCI state configuration to the UE and based on the maximum number of TCI states, the TCI state configuration specifying multiple TCI states including the one or more TCI states, wherein the one or more TCI states include a TCI state for a TRP group including one or more TRPs from the multiple TRPs.

27. A method for wireless communication at a user equipment (UE), the method comprising: sending, to a network node, UE capabilities indicating a maximum number of active transmit configuration indicator (TCI) states supported for coherent joint transmission (CJT) from a plurality of transmit reception points (TRPs); receiving, from the network node and based on the maximum number of TCI states, an indication of one or more TCI states for CJTs from at least a portion of the plurality of TRPs; receiving one or more downlink reference signals from at least the portion of the plurality of TRPs based on the indication; as well as A power delay profile (PDP) or a Doppler spectrum for channel estimation for at least a portion of the one or more TCI states is derived based on the one or more downlink reference signals.

28. The method of claim 27, wherein the indication is received in downlink control information (DCI), medium access control (MAC)-control element (CE) signaling, or radio resource configuration (RRC) signaling.

29. A method for wireless communication at a network node, the method comprising: For a user equipment (UE), receiving UE capabilities indicating a maximum number of active transmit configuration indicator (TCI) states supported for coherent joint transmission (CJT) from a plurality of transmit receive points (TRPs); sending, to the UE and based on the maximum number of TCI states, an indication of one or more TCI states for a CJT from at least a portion of the plurality of TRPs; as well as One or more downlink reference signals are sent from at least a portion of the multiple TRPs based on the indication.

30. The method of claim 29, wherein the indication is sent in downlink control information (DCI), medium access control (MAC)-control element (CE) signaling, or radio resource configuration (RRC) signaling.

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