WO2021063393A1

WO2021063393A1 - Transmission configuration indication (tci) list update and tci switch for channel state information (csi) reporting

Info

Publication number: WO2021063393A1
Application number: PCT/CN2020/119371
Authority: WO
Inventors: Hsuan-Li Lin; Zhixun Tang; Tsang-Wei Yu; Wenze Qu
Original assignee: Mediatek Inc.
Priority date: 2019-10-02
Filing date: 2020-09-30
Publication date: 2021-04-08
Also published as: WO2021062861A1

Abstract

A user equipment terminal (UE) operates in a wireless network. The UE receives a channel state information reference signal (CSI-RS) from a base station according to a transmission configuration indication (TCI) state in a CSI-RS configuration. The UE reports channel state information (CSI) to the base station. The UE receives, from the base station, indications to update a TCI state list and to switch the TCI state in the CSI-RS configuration for CSI reporting. The TCI state list update begins before the TCI state switch is completed. The TCI state refers to the TCI state list for spatial information for reception of the CSI-RS. The UE reports an out-of-bound indication to the base station for the CSI reporting in a time period when only one of the TCI state switch and the TCI state list update is completed.

Description

TRANSMISSION CONFIGURATION INDICATION (TCI) LIST UPDATE AND TCI SWITCH FOR CHANNEL STATE INFORMATION (CSI) REPORTING

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of PCT Application No. PCT/CN2019/109797 filed on October 2, 2019, the entirety of which is incorporated by reference herein.

TECHNICAL FIELD

Embodiments of the invention relate to wireless communications; more specifically, to the reporting of channel state information from a user equipment (UE) to a base station.

BACKGROUND

The Fifth Generation New Radio (5G NR) is a telecommunication standard for mobile broadband communications. 5G NR is promulgated by the 3rd Generation Partnership Project (3GPP) to significantly improve performance metrics such as latency, reliability, throughput, etc. In a 5G NR system, a UE receives a reference signal, such as a channel state information reference signal (CSI-RS) , from a base station for estimating the channel quality. The UE measures and calculates the channel condition, and reports the calculated channel condition to the base station. The base station transmits downlink signals based on the report sent from the UE. For example, the base station can adapt the downlink data rate and modulation scheme based on the UE’s report of channel state information (CSI) . The base station may send the UE a configuration update for the CSI reporting, and the UE receives the CSI-RS and reports the CSI according to the updated configuration.

The existing 5G NR technology can be further improved to benefit operators and users of the unlicensed spectrum. These improvements may also apply to other multi-access technologies and the telecommunication standards that employ these technologies.

SUMMARY

In one embodiment, a method is performed by a UE in a wireless network. The UE receives a CSI-RS from a base station according to a transmission configuration indication (TCI) state in a CSI-RS configuration. The UE reports CSI to the base station. The UE receives, from the base station, indications to update a TCI state list and to switch the TCI state in the CSI-RS configuration for CSI reporting. The TCI state list update begins before the TCI state switch is completed. Furthermore, the TCI state refers to the TCI state list for spatial information for reception of the CSI-RS. The UE reports an out-of-bound indication to the base station for the CSI reporting in a time period when only one of the TCI state switch and the TCI state list update is completed.

In another embodiment, a method is performed by a UE in a wireless network. The UE receives a CSI-RS from a base station according to a TCI state in a CSI-RS configuration. The UE reports CSI obtained from the CSI-RS to the base station. The UE receives, from the base station, indications to update a TCI state list and to switch the TCI state in the CSI-RS configuration for CSI reporting. The TCI state list update begins before the TCI state switch is completed. Furthermore, the TCI state refers to the TCI state list for spatial information for reception of the CSI-RS. The UE performs the CSI reporting to the base station according to the TCI state before the TCI state switch and the TCI state list before the TCI state list update until both the TCI state switch and the TCI state list update are completed.

In yet another embodiment, an apparatus such as a UE is provided for wireless communication. The apparatus includes a memory and processing circuitry coupled to the memory. The processing circuitry is configured to receive a CSI-RS from a base station according to a TCI state in a CSI-RS configuration. The processing circuitry is further configured to report CSI obtained from the CSI-RS to the base station, and to receive, from the base station, indications to update a TCI state list and to switch the TCI state in the CSI-RS configuration for CSI reporting. The TCI state list update begins before the TCI state switch is completed, and the TCI state refers to the TCI state list for spatial information for reception of the CSI-RS. The processing circuitry is further configured to report an out-of-bound indication to the base station for the CSI reporting in a time period when only one of the TCI state switch and the TCI state list update is completed.

The present disclosure provides a method for a UE to perform CSI reporting based on a received CSI-RS. The reporting depends on the timeline of a TCI state switch, which switches an old TCI state to a new TCI state for the CSI-RS, and the timeline of an active TCI state list update.

Other aspects and features will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments in conjunction with the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that different references to "an" or "one" embodiment in this disclosure are not necessarily to the same embodiment, and such references mean at least one. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

Figure 1 is a diagram illustrating a network in which the embodiments of the present invention may be practiced.

Figure 2 is a diagram illustrating an example of a CSI-RS configuration for CSI reporting according to one embodiment.

Figure 3 is a diagram illustrating an overview of the cases to be described according to some embodiments.

Figure 4A is a diagram illustrating a first case according to one embodiment.

Figure 4B is a diagram illustrating a first case according to another embodiment.

Figure 5 is a diagram illustrating a second case according to one embodiment.

Figure 6 is a diagram illustrating a third case according to one embodiment.

Figure 7 is a flow diagram illustrating a method for a UE to report CSI according to one embodiment.

Figure 8 is a block diagram illustrating an apparatus that performs wireless communication according to one embodiment.

DETAILED DESCRIPTION OF PREFERRED IMPLEMENTATIONS

In the following description, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known circuits, structures, and techniques have not been shown in detail in order not to obscure the understanding of this description. It will be appreciated, however, by one skilled in the art, that the invention may be practiced without such specific details. Those of ordinary skill in the art, with the included descriptions, will be able to implement appropriate functionality without undue experimentation.

Embodiments of the invention provide a procedure for a UE to report CSI to a base station when updates are performed to the UE’s CSI-RS configuration and an active TCI state list referred to by the CSI-RS configuration. More specifically, the updates are performed to (1) an active TCI state list and (2) a TCI state in the CSI-RS configuration for a CSI-RS. The TCI state provides a TCI index pointing to an entry in the active TCI state list. The entry includes spatial information for the reception of the CSI-RS.

The update performed to the TCI state in the CSI-RS configuration is also referred to as the TCI state switch, as the update switches the TCI index from a first TCI index (e.g., index #1) to a second TCI index (e.g., index #2) . The first TCI index and the second TCI index point to different entries in the TCI state list that correspond to different reception directions. The second TCI index refers to an entry in the active TCI state list, where the entry includes new spatial information for the UE to receive the CSI-RS. An example of the spatial information is the receiving (Rx) beam direction, which may be indicated by a quasi-collocation (QCL) type and an identifier of another reference signal which has been received by the UE with a given configuration of an Rx spatial filter (e.g. an angle of arrival) .

The update performed on the active TCI state list is also referred to as the “TCI state list update” or “list update. ” The list update modifies one or more entries in the active TCI state list. For example, the total number of TCI indices may be N1, and only a subset (N2) of which are active TCI states for CSI reporting (where N1 > N2) . Thus, there are N2 entries in the active TCI state list; not all of the TCI indices are stored in the active TCI state list. A list update may replace a first entry corresponding to TCI index #m with a second entry corresponding to TCI index #n, where TCI index #m and TCI index #n correspond to different Rx beam directions. Another list update may modify the content of an entry corresponding to TCI index #m without replacing TCI index #m by another TCI index.

Although a UE performs the TCI state list update and the TCI state switch within required time limits, the UE may be required to report the channel quality of a CSI-RS while one or both the TCI state list update and the TCI state switch is/are in progress. To prevent the UE from reporting invalid information and the base station from transmission based on the invalid information, the UE’s reporting follows the procedure to be disclosed below with reference to Figures 3, 4A, 4B, 5 and 6.

The disclosed method, as well as the apparatus and the computer product implementing the method, can be applied to wireless communication between a base station (e.g., a gNB in a 5G NR network) and UEs. It is noted that while the embodiments may be described herein using terminology commonly associated with 5G or NR wireless technologies, the present disclosure can be applied to other multi-access technologies and the telecommunication standards that employ these technologies.

Figure 1 is a diagram illustrating a network 100 in which embodiments of the present invention may be practiced. The network 100 is a wireless network which may be a 5G NR network. To simplify the discussion, the methods and apparatuses are described within the context of a 5G NR network. However, one of ordinary skill in the art would understand that the methods and apparatuses described herein may be applicable to a variety of other multi-access technologies and the telecommunication standards that employ these technologies.

The number and arrangement of components shown in Figure 1 are provided as an example. In practice, the network 100 may include additional devices, fewer devices, different devices, or differently arranged devices than those shown in Figure 1.

Referring to Figure 1, the network 100 may include a number of base stations (shown as BSs) , such as

base stations

120a, 120b, and 120c, collectively referred to as the base stations 120. In some network environments such as a 5G NR network, a base station may be known as a gNodeB, a gNB, and/or the like. In an alternative network environment, a base station may be known by other names. Each base station 120 provides communication coverage for a particular geographic area known as a cell, such as a

cell

130a, 130b or 130c, collectively referred to as cells 130. The radius of a cell size may range from several kilometers to a few meters. A base station may communicate with one or more other base stations or network entities directly or indirectly via a wireless or wireline backhaul.

A network controller 110 may be coupled to a set of base stations such as the base stations 120 to coordinate, configure, and control these base stations 120. The network controller 110 may communicate with the base stations 120 via a backhaul.

The network 100 further includes a number of UEs, such as UEs 150a, 150b, 150c, and 150d, collectively referred to as the UEs 150. The UEs 150 may be anywhere in the network 100, and each UE 150 may be stationary or mobile. The UEs 150 may also be known by other names, such as a mobile station, a subscriber unit, and/or the like. Some of the UEs 150 may be implemented as part of a vehicle. Examples of the UEs 150 may include a cellular phone (e.g., a smartphone) , a wireless communication device, a handheld device, a laptop computer, a cordless phone, a tablet, a gaming device, a wearable device, an entertainment device, a sensor, an infotainment device, Internet-of-Things (IoT) devices, or any device that can communicate via a wireless medium.

In one embodiment, the UEs 150 may communicate with their respective base stations 120 in their respective cells 130. A UE may have more than one serving cell; e.g., UE 150d may have both cell 130b and cell 130a as its serving cells. The transmission from a UE to a base station is called uplink transmission, and from a base station to a UE is called downlink transmission.

In one embodiment, each of the UEs 150 provides layer 3 functionalities through a radio resource control (RRC) layer, which is associated with the transfer of system information, connection control, and measurement configurations. Each of the UEs 150 further provides layer 2 functionalities through a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer. The PDCP layer is associated with header compression/decompression, security, and handover support. The RLC layer is associated with the transfer of packet data units (PDUs) , error correction through automatic repeat request (ARQ) , concatenation, segmentation, and reassembly of RLC service data units (SDUs) . The MAC layer is associated with the mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs) , de-multiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through hybrid ARQ (HARQ) , priority handling, and logical channel prioritization. Each of the UEs 150 further provides layer 1 functionalities through a physical (PHY) layer, which is associated with error detection on the transport channels, forward error correction (FEC) coding/decoding of the transport channels, interleaving, rate matching, mapping onto physical channels, modulation/demodulation of physical channels, and multiple-input and multiple-output (MIMO) antenna processing, etc.

In a 5G NR network, a base station such as a gNB may configure and activate a bandwidth part (BWP) for communication with UEs in a serving cell, through a radio resource control (RRC) configuration according to an RRC layer protocol. The activated BWP is referred to as the frequency resources, and the time scheduled for the communication is referred to as the time resources. The frequency resources and the time resources are herein collectively referred to as the time-and-frequency resources. In a wireless network, different serving cells may be configured with different time-and-frequency resources.

Multiple time and frequency configurations are supported by NR. With respect to time resources, a frame may be 10 milliseconds (ms) in length, and may be divided into ten subframes of 1 ms each. Each subframe may be further divided into multiple equal-length time slots (also referred to as slots) , and the number of slots per subframe may be different in different configurations. Each slot may be further divided into multiple equal-length symbol durations (also referred to as symbols) ; e.g., 7 or 14 symbols. With respect to frequency resources, NR supports multiple different subcarrier bandwidths. Contiguous subcarriers (also referred to as resource elements (REs) ) are grouped into one resource block (RB) . In one configuration, one RB may contain 12 subcarriers.

A base station may transmit downlink reference signals to a UE or a group of UEs in a serving cell. One of the reference signals is the CSI-RS. A base station can configure a set of time-and-frequency resources for a CSI-RS configuration used by the UE to receive one or more CSI-RSs. According to the CSI-RS configuration, the UE receives a CSI-RS from a target Rx beam direction with given time-and-frequency resources for channel quality estimation, frequency and time tracking, among other uses. A CSI-RS may be periodic, aperiodic, or semi-persistent. Based on the received CSI-RS, the UE calculates and reports channel state information (CSI) to the base station. The reported CSI indicates the quality of the radio channel or link between an antenna port of the base station and the UE. The reported CSI includes channel quality information (CQI) , which may be used by the base station to determine the modulation and coding scheme (MCS) for downlink transmission. As an example, the CQI may be reported as a layer-1 reference signal received power (L1-RSRP) . In addition to the CQI, the reported CSI may also include a precoding matrix index (PMI) and a rank indicator (RI) . The PMI and the RI may be used by the base station to determine a MIMO precoding scheme and the number of UE-preferred transmission layers, respectively, for downlink transmission.

In one embodiment, the UE obtains the target Rx beam direction of the CSI-RS from a target TCI state in the CSI-RS configuration and the active TCI state list. The target Rx beam (used for CSI reporting) is aligned with the Rx beam used for downlink data reception. The target TCI state (used for CQI reporting) is in the active TCI list which is also used for downlink data reception.

Figure 2 is a diagram 200 illustrating an example of a CSI-RS configuration 201 for CSI reporting according to one embodiment. The CSI-RS configuration 201 contains information for receiving a CSI-RS for CSI reporting. In this example, the CSI-RS to be received is identified as CSI-RS #1 (i.e., the target CSI-RS) . Among other information (such as time-and-frequency resources information) , the CSI-RS configuration includes a TCI state which can be used by the UE 150 to obtain spatial information for receiving CSI-RS #1. From the spatial information, the UE 150 may infer the angle-of-arrival (e.g., Rx beam direction) for receiving CSI-RS #1. The TCI state in the CSI-RS configuration 201 includes a TCI index, which points to an entry in a reference list, called an active TCI state list 202. Each TCI state in the active TCI state list 202 is associated with, or corresponding to, a reference signal and a QCL type. The QCL types may include: QCL-type A: (Doppler shift, Doppler spread, average delay, delay spread) ; QCL-type B: (Doppler shift, Doppler spread) ; QCL-type C: (Doppler shift, average delay) ; and QCL-type D: (spatial Rx parameter) . In this example, TCI index #1 is associated with a synchronous signal block SSB #1 with QCL-type D. The UE 150 configured with the TCI state = TCI index #1 (i.e., the target TCI state) may use the Rx beam for receiving SSB #1 to receive CSI-RS #1.

The UE 150 may store the CSI-RS configuration 201 and the active TCI state list 202 in a memory 240. The UE 150 receives the CSI-RS via a radio receiver (Rx) 210, computes the channel quality from the received CSI-RS using a processor 230, and sends a CSI report including the computed channel quality to the base station via a radio transmitter (Tx) 220.

The UE 150 may receive control information from a base station to switch its TCI state in the CSI-RS configuration 201 via an RRC configuration, media access control (MAC) control element (CE) , or downlink control information (DCI) . The base station may send an update on the active TCI list 202 to the UE 150 via MAC-CE.

In one embodiment, the UE 150 may receive a TCI state table of (128, 64) entries via the RRC configuration. Out of the (128, 64) entries, the UE 150 may receive an indication via MAC-CE that a subset of the entries (e.g., 8 entries) are “active. ” Thus, the UE 150 may store the 8 entries in the active TCI state list 202. Each of the 8 entries is identified by a TCI index and includes a reference signal and a QCL type. In the description hereinafter, the term “TCI state list” is used interchangeably as the “active TCI state list, ” unless otherwise specified.

For ease of description and illustration, the following description refers to the TCI state switch as “Event A, ” and the TCI state list update as “Event B. ” The horizontal axis represents time. Herein, the update process to TCI information for CSI reporting includes both Event A and Event B. Event A is completed at point_A in time, and Event B is completed at point_B in time.

Figure 3 is a diagram 300 illustrating an overview of the cases to be described in the embodiments of Figures 4A, 4B, 5, and 6. In the first case, Event B begins before the beginning of Event A, and is completed after the beginning of Event A but before the completion of Event A. In the second case, Event A begins before the beginning of Event B, and is completed after the beginning of Event B but before the completion of Event B. In the third case, Event B begins and ends (i.e., is completed) before the beginning of Event A.

The update process described herein includes both Event A and Event B, where Event B begins before Event A is completed. Before either one of Event A and Event B begins (referred to as the “pre-update period” ) , the UE reports the CSI according to the old TCI state and the old TCI state list. After both Event A and Event B are completed (referred to as the “post-update period” ) , the UE reports the CSI according to the new (i.e., updated) TCI state and the new (i.e., updated) TCI state list. Between the pre-update period and the post-update period, the CSI reporting depends on which of the three cases occurs. In the embodiments shown in Figures 4A, 4B, 5, and 6, the TCI state switch (Event A) requires a processing time Ta and the TCI state list update (Event B) requires a processing time Tb. The lengths of Ta and Tb are limited by requirements specified in the 5G NR standards (e.g., TS 38.133, section 8.10) , which is outside the scope of this disclosure.

Figure 4A is a diagram illustrating the first case in detail according to one embodiment. In the first case, Event B begins before the beginning of Event A, and is completed after the beginning of Event A but before the completion of Event A. The UE reports the CSI according to the old TCI state and the old TCI state list throughout Event B and Event A until point_A when Event A is completed. After Event A is completed, the UE reports the CSI according to the new TCI state list and the new TCI state.

Figure 4B is a diagram illustrating the first case in detail according to another embodiment. The order in which Event A and Event B occur is the same as in Figure 4A. The UE reports the CSI according to the old TCI state and the old TCI state list throughout Event B until point_B when Event B is completed. Between point_A and point_B where Event B is completed but Event A is still in progress, the UE may report the CSI as out-of-bound; e.g., by reporting a predetermined value (e.g., RSRP_0) as the channel quality information (CQI) . In one embodiment, the predetermined value may represent the lowest RSRP value (e.g., RSRP_0) .

Figure 5 is a diagram illustrating the second case in detail according to one embodiment. In the second case, Event A begins before the beginning of Event B, and is completed when Event B is still in progress. The UE reports the CSI according to the old TCI state and the old TCI state list throughout Event A until point_A at which Event A is completed. After point_A, the UE has the capability to report the CSI with a new TCI state, but the active TCI state list for data reception has not finished updating. Between point_A and point_B where Event A is completed but Event B is still in progress, the UE reports the CSI as out-of-bound; e.g., by reporting a predetermined value (e.g., RSRP0) as the CQI. After Event B is completed, the UE reports the CSI according to the new TCI state and the new TCI state list.

Figure 6 is a diagram illustrating the third case in detail according to one embodiment. In the third case, Event B begins and is completed before the beginning of Event A (point_A0) . The UE reports the CSI according to the old TCI state and the old TCI state list throughout Event B until point_B at which Event B is completed. After point_B, the UE can refer to the new TCI state list to receive data transmission. However, the CSI-RS configuration for CSI reporting stays at the old TCI state. Thus, the CQI feedback can also be out-of-bound. Between point_A and point_B where Event B is completed but Event A is still in progress, the UE reports the CSI as out-of-bound; e.g., by reporting a predetermined value (e.g., RSRP0) as the CQI. After Event A is completed, the UE reports the CSI according to the new TCI state and the new TCI state list.

As disclosed herein, the time period between point_A and point_B may start at point_Aand end at point_B as in Figure 5, or start at point_B and end at point_Aas in Figures 4A, 4B, and 6. The time period between point_A and point_B is when only one of the TCI state switch and the TCI state list update is completed.

Figure 7 is a flow diagram illustrating a method 700 performed by a UE (e.g., the UE 150 in Figure 1 and/or the apparatus 800 in Figure 8) in a wireless network according to one embodiment. The method 700 starts at step 710 when the UE receives a CSI-RS from a base station according to a TCI state in a CSI-RS configuration. The UE at step 720 reports the CSI to the base station. The UE at step 730 receives, from the base station, indications to update a TCI state list and to switch the TCI state in the CSI-RS configuration for CSI reporting. The TCI state list update begins before the TCI state switch is completed. Furthermore, the TCI state refers to the TCI state list for spatial information for reception of the CSI-RS. The UE at step 740 reports an out-of-bound indication to the base station for the CSI reporting in a time period when only one of the TCI state switch and the TCI state list update is completed.

In one embodiment, after completion of both the TCI state list update and the TCI state switch, the UE reports an updated CSI of the CSI-RS to the base station according to the updated TCI state in the CSI-RS configuration and the updated TCI state list. In one embodiment, the spatial information includes a beam direction for the reception of the CSI-RS. In one embodiment, the out-of-bound indication includes a predetermined value as the CQI. In one embodiment, the out-of-bound indication includes a lowest reference signal received power (e.g., RSRP_0) as the CQI.

Figure 8 is a block diagram illustrating elements of an apparatus 800 performing wireless communication with a base station 850 according to one embodiment. In one embodiment, the apparatus 800 may be a UE and the base station 850 may be a gNb or the like, both of which may operate in a wireless network, such as the wireless network 100 in Figure 1. In one embodiment, the apparatus 800 may be any of the UEs 150 in Figure 1.

As shown, the apparatus 800 may include an antenna 810, and a transceiver circuit (also referred to as a transceiver 820) including a transmitter and a receiver configured to provide radio communications with another station in a radio access network, including communication in an unlicensed spectrum. The transmitter and the receiver may include filters in the digital front end for each cluster, and each filter can be enabled to pass signals and disabled to block signals. The apparatus 800 may also include processing circuitry 830 which may include one or more control processors, signal processors, central processing units, cores, and/or processor cores. The apparatus 800 may also include a memory circuit (also referred to as memory 840) coupled to the processing circuitry 830. The apparatus 800 may also include an interface (such as a user interface) . The apparatus 800 may be incorporated into a wireless system, a station, a terminal, a device, an appliance, a machine, and IoT operable to perform wireless communication in a multi-access network, such as a 5G NR network. It is understood the embodiment of Figure 8 is simplified for illustration purposes. Additional hardware components may be included.

In one embodiment, the apparatus 800 may store and transmit (internally and/or with other electronic devices over a network) code (composed of software instructions) and data using computer-readable media, such as non-transitory tangible computer-readable media (e.g., computer-readable storage media such as magnetic disks; optical disks; read-only memory; flash memory devices) and transitory computer-readable transmission media (e.g., electrical, optical, acoustical or other forms of propagated signals) . For example, the memory 840 may include a non-transitory computer-readable storage medium that stores computer-readable program code. The code, when executed by the processors, causes the processors to perform operations according to embodiments disclosed herein, such as the method disclosed in Figure 7.

Although the apparatus 800 is used in this disclosure as an example, it is understood that the methodology described herein is applicable to any computing and/or communication device capable of performing wireless communications.

The operations of the flow diagram of Figure 7 has been described with reference to the exemplary embodiments of Figures 1, 2, and 8. However, it should be understood that the operations of the flow diagram of Figure 7 can be performed by embodiments of the invention other than the embodiments of Figures 1, 2, and 8, and the embodiments of Figures 1, 2, and 8 can perform operations different than those discussed with reference to the flow diagram. While the flow diagram of Figure 7 shows a particular order of operations performed by certain embodiments of the invention, it should be understood that such order is exemplary (e.g., alternative embodiments may perform the operations in a different order, combine certain operations, overlap certain operations, etc. ) .

Various functional components or blocks have been described herein. As will be appreciated by persons skilled in the art, the functional blocks will preferably be implemented through circuits (either dedicated circuits, or general-purpose circuits, which operate under the control of one or more processors and coded instructions) , which will typically comprise transistors that are configured in such a way as to control the operation of the circuity in accordance with the functions and operations described herein.

While the invention has been described in terms of several embodiments, those skilled in the art will recognize that the invention is not limited to the embodiments described, and can be practiced with modification and alteration within the spirit and scope of the appended claims. The description is thus to be regarded as illustrative instead of limiting.

Claims

A method performed by a user equipment terminal (UE) in a wireless network, comprising:

receiving a channel state information reference signal (CSI-RS) from a base station according to a transmission configuration indication (TCI) state in a CSI-RS configuration;

reporting channel state information (CSI) to the base station;

receiving, from the base station, indications to update a TCI state list and to switch the TCI state in the CSI-RS configuration for CSI reporting, wherein TCI state list update begins before TCI state switch is completed, and wherein the TCI state refers to the TCI state list for spatial information for reception of the CSI-RS; and

reporting an out-of-bound indication to the base station for the CSI reporting in a time period when only one of the TCI state switch and the TCI state list update is completed.
The method of claim 1, further comprising:

after completion of both the TCI state list update and the TCI state switch, reporting an updated CSI of the CSI-RS to the base station according to an updated TCI state in the CSI-RS configuration and an updated TCI state list.
The method of claim 1, wherein the TCI state list update begins before the TCI state switch begins, and is completed before the TCI state switch is completed.
The method of claim 1, wherein the TCI state list update begins before the TCI state switch begins, and is completed before the TCI state switch begins.
The method of claim 1, wherein the TCI state switch begins before the TCI state list update begins, and is completed before the TCI state list update is completed.
The method of claim 1, wherein the spatial information includes a beam direction for the reception of the CSI-RS.
The method of claim 1, wherein the out-of-bound indication includes a lowest reference signal received power as channel quality information (CQI) .
The method of claim 1, wherein in response to the TCI state switch, the method further comprises:

switching the TCI state in the CSI-RS configuration from a first TCI index to a second TCI index, wherein the first TCI index and the second TCI index point to different entries in the TCI state list that correspond to different reception directions.
The method of claim 1, wherein the spatial information is indicated by a quasi-collocation (QCL) type and an identifier of another reference signal.
A method performed by a user equipment terminal (UE) in a wireless network, comprising:

receiving a channel state information reference signal (CSI-RS) from a base station according to a transmission configuration indication (TCI) state in a CSI-RS configuration;

reporting channel state information (CSI) obtained from the CSI-RS to the base station;

receiving, from the base station, indications to update a TCI state list and to switch the TCI state in the CSI-RS configuration for CSI reporting, wherein TCI state list update begins before TCI state switch is completed, and wherein the TCI state refers to the TCI state list for spatial information for reception of the CSI-RS; and

performing the CSI reporting to the base station according to the TCI state before the TCI state switch and the TCI state list before the TCI state list update until both the TCI state switch and the TCI state list update are completed.
An apparatus for wireless communication, the apparatus being a user equipment (UE) , comprising:

a memory; and

processing circuitry coupled to the memory and configured to:

receive a channel state information reference signal (CSI-RS) from a base station according to a transmission configuration indication (TCI) state in a CSI-RS configuration;

report channel state information (CSI) to the base station;

receive, from the base station, indications to update a TCI state list and to switch the TCI state in the CSI-RS configuration for CSI reporting, wherein TCI state list update begins before TCI state switch is completed, and wherein the TCI state refers to the TCI state list for spatial information for reception of the CSI-RS; and

report an out-of-bound indication to the base station for the CSI reporting in a time period when only one of the TCI state switch and the TCI state list update is completed.
The apparatus of claim 11, wherein the processing circuitry is further operative to:

after completion of both the TCI state list update and the TCI state switch, reporting an updated CSI of the CSI-RS to the base station according to an updated TCI state in the CSI-RS configuration and an updated TCI state list.
The apparatus of claim 11, wherein the TCI state list update begins before the TCI state switch begins, and is completed before the TCI state switch is completed.
The apparatus of claim 11, wherein the TCI state list update begins before the TCI state switch begins, and is completed before the TCI state switch begins.
The apparatus of claim 11, wherein the TCI state switch begins before the TCI state list update begins, and is completed before the TCI state list update is completed.
The apparatus of claim 11, wherein the spatial information includes a beam direction for the reception of the CSI-RS.
The apparatus of claim 11, wherein the out-of-bound indication includes a lowest reference signal received power as channel quality information (CQI) .
The apparatus of claim 11, wherein in response to the TCI state switch, the processing circuitry is further operative to:

switching the TCI state in the CSI-RS configuration from a first TCI index to a second TCI index, wherein the first TCI index and the second TCI index point to different entries in the TCI state list that correspond to different reception directions.
The apparatus of claim 11, wherein the spatial information is indicated by a quasi-collocation (QCL) type and an identifier of another reference signal.
The apparatus of claim 11, wherein the wireless network is a 5G New Radio (NR) network.