CN117479314A

CN117479314A - Method and user equipment for communicating with multiple TRPs

Info

Publication number: CN117479314A
Application number: CN202310937993.4A
Authority: CN
Inventors: 霍达·沙莫哈马迪安; 裵正铉
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2022-07-29
Filing date: 2023-07-27
Publication date: 2024-01-30

Abstract

Methods and user equipment for communicating with multiple TRPs are disclosed. According to an embodiment, the method comprises: receiving Transmission Configuration Indicator (TCI) state information, wherein the TCI state information specifies an indicated TCI state set comprising one or more active TCI states; receiving an indication of an association between the indicated TCI state set and one or more TRPs; and identifying one or more of the multiple TRPs based on the associated indication to apply a configuration of the indicated TCI state set.

Description

Method and user equipment for communicating with multiple TRPs

The disclosure of which claims priority from U.S. provisional application No. 63/393,772, U.S. provisional application No. 63/408,086, U.S. provisional application No. 63/425,301, U.S. provisional application No. 63/457,096, U.S. provisional application No. 63/457, 4 at 2023, and U.S. non-provisional application No. 18/214,517, 26 at 2023, 7, 9, 19, 2022, 11, 14, and fully described herein.

Technical Field

The present disclosure relates generally to wireless communications. More particularly, the subject matter disclosed herein relates to improvements to cellular communications having multiple transmission and reception points (multi-TRPs).

Background

The third generation partnership project (3 GPP) is a collaborative project among a set of telecommunications associations, the initial goal of which is to develop globally applicable standards and specifications for third generation (3G) mobile systems. In release 17 ("rel.17") of the 3GPP specifications, the 3GPP specifies a unified Transmission Configuration Indicator (TCI) framework for configuring and signaling transmission parameters for different reference signals and different scenarios between User Equipment (UE) and a single Transmission and Reception Point (TRP), where TRP is an antenna array (with one or more antenna elements) located at a specific geographic location. A UE may be any device (such as a smart phone) that is used directly by an end-user (end-user) to communicate with a base station or node in a cellular network, such as a next generation NodeB (gNB). A node may connect to and communicate wirelessly with a UE through one or more TRPs. The transmission between the UE and the base station via a single TRP may be characterized as a single TRP transmission and the transmission between the UE and the base station via multiple TRPs may be characterized as a multiple TRP transmission. multi-TRP transmission generally has many advantages over single TRP transmission, such as increased Downlink (DL) data rate (especially for UEs closer to the radio cell edge) and increased communication reliability.

The unified TCI framework aims to reduce the delay and overhead of beam pointing, thereby enhancing system performance, especially in high mobility scenarios. One way of simplifying signaling by the unified TCI framework is by allowing the base station to indicate transmission parameters for different reference signals using a single TCI field in the Downlink Control Information (DCI). The TCI field may select a TCI state associated with a source reference signal (e.g., a Synchronization Signal Block (SSB), a channel state information reference signal (CSI-RS), or a Sounding Reference Signal (SRS)) and being of a quasi-parity (QCL) type. The QCL type specifies how transmission parameters of the source reference signal may be applied to other reference signals quasi-co-located with the source reference signal. For example, the base station may signal a TCI state indicating beamforming parameters for CSI-RS and how they may be applied to a Physical Downlink Shared Channel (PDSCH), a Physical Downlink Control Channel (PDCCH), etc.

Although rel.17 specifies a unified TCI framework for single TRP transmission, it does not specify a unified TCI framework for multi TRP transmission. Accordingly, there is a need for User Equipment (UE) and methods disclosed herein to provide a corresponding unified TCI framework for multi-TRP transmissions.

Disclosure of Invention

In some embodiments, a method comprises: receiving Transmission Configuration Indicator (TCI) state information, wherein the TCI state information specifies an indicated TCI state set comprising one or more active TCI states; receiving an indication of an association between the indicated TCI state set and one or more TRPs; and identifying one or more of the multiple TRPs based on the associated indication to apply a configuration of the indicated TCI state set.

In some embodiments, a system includes a UE device, wherein the UE device includes a processor and a memory containing instructions, wherein the instructions, when executed by the processor, cause the UE device to: receiving Transmission Configuration Indicator (TCI) state information, wherein the TCI state information specifies an indicated TCI state set comprising one or more active TCI states; receiving an indication of an association between the indicated TCI state set and one or more TRPs; and identifying one or more of the multiple TRPs based on the associated indication to apply a configuration of the indicated TCI state set.

Drawings

In the following sections, aspects of the subject matter disclosed herein will be described with reference to exemplary embodiments shown in the drawings, in which:

fig. 1 illustrates an example wireless communication architecture according to an embodiment.

Fig. 2, 3, 4, 5, 6, 7, 8, and 9 illustrate examples of TCI state/TRP association behavior according to embodiments.

Fig. 10 illustrates an example of PDSCH reception behavior according to an embodiment.

Fig. 11, 12, 13, 14 and 15 illustrate examples of UE behavior when TCI state is applied according to an embodiment.

Fig. 16, 17 and 18 illustrate example methods of communication between a UE and multiple TRPs according to embodiments.

Fig. 19 is a block diagram of an electronic device in a network environment according to an embodiment.

Fig. 20 shows a system including a UE and a gNB in communication with each other.

Detailed Description

In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be understood by those skilled in the art that the disclosed aspects may be practiced without these specific details. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to obscure the subject matter disclosed herein.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment disclosed herein. Thus, the appearances of the phrase "in one embodiment" or "in an embodiment" or "according to one embodiment" (or other phrases having similar meanings) in various places throughout this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In this regard, as used herein, the word "exemplary" means "serving as an example, instance, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Similarly, hyphenated english terms may occasionally be used interchangeably with corresponding non-hyphenated versions, and uppercase english entries may be used interchangeably with corresponding non-uppercase versions. Such occasional interchangeable uses should not be considered inconsistent with each other.

Furthermore, depending on the context discussed herein, singular terms may include the corresponding plural forms and plural terms may include the corresponding singular forms. It should also be noted that the various figures (including component figures) shown and discussed herein are for illustrative purposes only and are not drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals have been repeated among the figures to indicate corresponding and/or analogous elements.

The terminology used herein is for the purpose of describing some example embodiments only and is not intended to be limiting of the claimed subject matter. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

It will be understood that when an element or layer is referred to as being "on," "connected to," or "coupled to" another element or layer, it can be directly on, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly connected to," or "directly coupled to" another element or layer, there are no intervening elements or layers present. Like reference numerals refer to like elements throughout. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

As used herein, the terms "first," "second," and the like are used as labels for nouns following them, and do not imply any type of ordering (e.g., spatial, temporal, logical, etc.) unless explicitly defined so. Furthermore, the same reference numbers may be used across two or more drawings to refer to parts, components, blocks, circuits, units, or modules having the same or similar functionality. However, such use is merely for simplicity of illustration and ease of discussion; it is not intended that the construction or architectural details of such components or units be the same in all embodiments or that such commonly referenced parts/modules be the only way to implement some example embodiments disclosed herein.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this subject matter belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

As used herein, the term "module" refers to any combination of software, firmware, and/or hardware configured to provide the functionality described herein in connection with the module. For example, software may be embodied as a software package, code, and/or instruction set or instructions, and the term "hardware" as used in any of the embodiments described herein may include, for example, components, hardwired circuitry, programmable circuitry, state machine circuitry, and/or firmware that stores instructions executed by the programmable circuitry, either alone or in any combination. Modules may be collectively or individually embodied as circuitry forming part of a larger system, such as, but not limited to, an Integrated Circuit (IC), a system-on-a-chip (SoC), a component, and the like.

Fig. 1 illustrates an example wireless communication architecture 100 in which a UE communicates with a gNB 110 via one or more TRPs (121, 122, 131, 132, 141, 142, 143, 150) according to an embodiment. The gNB may be a 5G radio node connecting the UE (160, 161) to the fifth generation (5G) network core 101 using a New Radio (NR) interface, wherein the UE (160, 161) may comprise a 5G NR device. The gNB includes a Centralized Unit (CU) 111, a Distributed Unit (DU) 112 and a DU 113.CU 111 typically supports protocols in higher layers, and DUs typically support protocols in lower layers.

At the physical layer, each DU may support one or more cells (120, 130, 140), and each cell may be associated with a unique Physical Cell ID (PCI). TRP 121 and TRP 122 are part of cell 120, TRP 131 and TRP 132 are part of cell 130, and TRP 141, TRP 142, and TRP 143 are part of cell 140. The UE may communicate with the gNB through one or more TRPs associated with one or more cells. For example, UE 160 communicates with TRP 121 and TRP 122 as part of cell 120 and TRP 131 as part of cell 130, and UE 161 communicates with TRP 141, TRP 142, and TRP 143 as part of cell 140. Using the cell selection process, UE 160 may determine that cell 130 provides the best communication with the gNB and represent cell 130 as the serving cell. Communication between TRP associated with a serving cell and a UE may be referred to as "intra-cell" communication, and communication between TRP associated with a non-serving cell and a UE may be referred to as "inter-cell" communication.

As shown in fig. 1, UE 160 communicates with TRP 131 via radio signal beam D and radio signal beam E, with one beam for DL and one beam for Uplink (UL); similarly, UE 160 communicates with TRP 121 via radio signal beam a and radio signal beam B. Differently, UE 160 communicates with TRP 122 via a single radio signal beam C for both DL and UL. The gNB is generally responsible for beam management and beam pointing. For example, the gNB determines whether the same or different signal beams are used for UL and DL transmissions between the UE and TRP based on channel conditions and/or other constraints, such as maximum allowed exposure (MPE) constraints, and transmits the determination to the UE, e.g., as TCI status information in DCI. When the gNB schedules multi-TRP transmission with the UE, the gNB may operate in a single DCI scheme to schedule the UE using the same DCI for multiple TRPs or in a multi-DCI scheme to schedule the UE using independent DCIs for each TRP.

Up to rel.17, the beam management and beam indication procedure for each channel or Reference Signal (RS) may be configured separately according to its performance target. However, the different beam management and beam indication procedures for the different channels or RSs will increase complexity, overhead and delay and will result in significant throughput degradation, especially for high mobility scenarios and/or frequency range 2 (FR 2) scenarios with a large number of configured TCI states. Thus, in rel.17, a unified TCI framework is specified for single TRP transmissions, where a single joint DL/UL TCI state or a single pair of DL TCI state and UL TCI state is indicated for UE-specific reception on PDCCH/PDSCH or dedicated Physical Uplink Control Channel (PUCCH) and PUSCH resources based on dynamic grant/configuration grant. The joint DL/UL TCI state may be used when beam correspondence between DL and UL is assumed, and the paired DL TCI state and UL TCI state may be used when beam correspondence (e.g., MPE event) is not assumed.

The unified TCI state pool may be configured via higher layer signaling for each bandwidth part (BWP)/Component Carrier (CC). In general, the TCI states for DL and UL transmissions may be configured from separate pools, but in the case of joint DL/UL TCI states, the same pool of DL TCI states may also be shared for UL transmissions. That is, the unified TCI state may be a joint DL/UL TCI state (i.e., jointULDL type), which means that the serving cell is configured with a single pool (dlorjoin-TCIState-r 17) for both DL and UL operations, or a pair of separate DL TCI states and UL TCI state (i.e., separator uldl type), which means that the serving cell may be configured with two pools, i.e., one pool (dlorjoin-TCIState-r 17) for DL operations and one pool (UL-TCIState-r 17) for UL operations. The maximum number of TCI states for configuration of the joint DL/UL TCI state pool may be per BWP or per CC 128, and the number of TCI states that the UE may support for configuration of DL and UL operations may be UE capabilities including the following candidate values: for DL, 64 and 128 per BWP or per CC, and for UL, 32 and 64 per BWP or per CC.

The target channels and target RSs supported in the rel.17 unified TCI framework for DL transmissions that will share the same indicated unified TCI state may be UE-specific PDCCH/PDSCH, non-UE-specific PDCCH/PDSCH associated with serving cell PCI, aperiodic CSI-RS resources for CSI, and aperiodic CSI-RS resources for beam management. Periodic CSI-RS resources and semi-persistent CSI-RS resources may be excluded from supported target RSs for DL to allow beam measurements and CSI reporting for different candidate beams in a unified TCI state before switching to these different candidate beams. The TCI states of the periodic CSI-RS resources and the semi-persistent CSI-RS resources may be configured by Radio Resource Control (RRC) and Medium Access Control (MAC) Control Elements (CEs). For supported target CSI-RS resources (e.g., aperiodic CSI-RS for beam management and aperiodic CSI-RS for CSI acquisition), there is no QCL-info field for the aperiodic CSI-RS inside CSI-associtreportconfigmnfo (where QCL information for the aperiodic resources can be configured as in the rel.17 specification) can be implicitly determined to apply the indicated uniform TCI state to the supported target RS.

For a supported target SRS resource (e.g., an aperiodic SRS for beam management or an SRS for any time domain behavior of codebook, non-codebook and antenna switching), a bit parameter followUnifiedTCI-State-r17 may be RRC configured at an SRS set level configuration to determine that the indicated unified TCI State applies to the supported target SRS. For all other supported UL target channels including PUCCH and DG/CG PUSCH, the UE may follow the indicated unified TCI state if they belong to BWP/CCs that may be configured with the unified TCI state.

The signaling medium for updating the unified TCI state may be UE-specific DCI with or without PDSCH allocation. The unified TCI state may be indicated by a code point value in the TCI field of DCI format 1_1 or DCI format 1_2, where the code point value maps to one or more activated unified TCI states (e.g., up to 8 activated states) activated by a MAC CE command. Each of the code point values may be mapped to a joint DL/UL TCI state, a pair of DL TCI state and UL TCI state, a DL-only TCI state for a separate DL/UL TCI state, or a UL-only TCI state for a separate DL/UL TCI state. The UE may acknowledge the unified TCI state update by the same Acknowledgement (ACK)/Negative Acknowledgement (NACK) transmission used to schedule the DL DCI, and apply the newly indicated unified TCI state at least Y symbols after the last symbol of the transmitted ACK, where Y may be determined based on the carrier with the smallest subcarrier spacing (SCS).

The rel.17 unified TCI framework supports common TCI state ID updating and activation of a set of inter-configured CCs/BWP for at least UE-specific PDCCH/PDSCH and/or UE-specific PUSCH/PUCCH. In this way, the list of serving cells may be RRC configured, and the TCI relationship of these serving cells may be updated simultaneously with the MAC CE command. Furthermore, the rel.17 unified TCI framework supporting common TCI states across a set of configured CCs allows a single RRC TCI state pool to be shared among these configured CCs. For such a CC list, the TCI state pool of RRC configurations may not exist in the PDSCH configuration for each BWP/CC, and the TCI state pool of reference RRC configurations in the reference BWP/CC is replaced.

The rel.17 unified TCI framework may be applicable to intra-cell transmission scenarios and inter-cell transmission scenarios. That is, the activated rel.17 unified TCI state may be directly or indirectly associated with PCI(s) other than the serving cell PCI. To illustrate, a secondary Synchronization Signal Block (SSB) indicated as a UL source RS in a unified TCI state may be associated with a PCI (directly) different from a serving cell PCI, or CSI-RS resources indicated as a source RS in a unified TCI state may be quasi-co-located with an SSB (indirectly) from a physical cell different from the serving cell. For an inter-cell transmission scenario, the UE may support more than one rel.17 activated DL TCI state per band (i.e., multiple TCI state code point values may be activated by a MAC CE command, where the MAC CE command is followed by a DCI indication of a single code point value). If the UE does not support such capability, the UE may not support a DCI-based unified TCI indication and a MAC CE beam indication (i.e., a single unified TCI status code point activated by a MAC CE) may be used to switch between two different DL receptions along two different beams.

The application of the unified TCI state for the indication of PDCCH and corresponding PDSCH reception may be determined for RRC configuration of each control resource set (CORESET). In some cases, the UE applies the indicated unified TCI state to PDCCH and PDSCH reception, such as for CORESET associated only with UE-specific reception (except CORESET # 0). For PDCCH and corresponding PDSCH reception on CORESET #0, it may be determined, per CORESET, in accordance with the RRC configuration, whether to apply the indicated rel.17 unified TCI state to CORESETs in the CC associated with only non-UE-specific reception or CORESETs associated with both UE-specific and non-UE-specific reception. For a Dynamic Grant (DG) PDSCH scheduled by CORESET, the UE may apply the indicated unified TCI state according to CORESET RRC configuration. For SPS PDSCH, the UE may apply the indicated unified TCI state according to the core configuration of the active DCI. That is, DG-based or SPS-based PDSCH transmissions may follow the indication of the corresponding CORESET entirely to determine whether to apply the indicated unified TCI state.

In the rel.17 unified TCI status framework, each DCI indicates an upcoming unified TCI status to be used in a time window manner (e.g., after a beam application time), and this may not necessarily be related to the TCI status of the scheduled PDSCH. That is, since the UE will apply the previously indicated and currently active unified TCI at each time instance, defining the default TCI state is less important in rel.17, except for the very first unified TCI state indication. However, using the RRC configuration of each CORESET as an indication of whether to apply the indicated unified TCI may create a beam ambiguity (ambiguity) scenario at the UE and thus force defining the default TCI rule definition for the rel.17 unified TCI state.

The beam application time may be defined as a first slot of a unified TCI to which an indication is applied at least Y symbols after a last symbol of an acknowledgement of the corresponding DCI. The Y symbols may be configured for each DL BWP and UL BWP by the gNB based on the UE capability, and may be determined based on the carrier with the smallest SCS among the carrier(s) to which the beam indication is applied. The configured value ranges of the RRC parameters for the beam application time are 1, 2, 4, 7, 14, 28, 42, 56, 70, 84, 98, 112, 224, and 336 symbols. If the MAC CE command activates only a single TCI code point, the beam application time may follow the rel.16 application timeline for MAC CE activation.

After the UE receives higher layer configuration of the unified TCI state (such as via RRC configuration), and before applying the TCI state from the indication of the configured TCI state, the UE assumes that the DL target channel is quasi-co-sitable with the SSB identified during the initial access procedure, and that the UL target channel assumes the same UL spatial filter as that used for PUSCH transmission scheduled by a Random Access Response (RAR) UL grant during the initial access procedure.

According to some embodiments, the present disclosure provides a unified TCI state framework for multi-TRP operation. Specifically, the present disclosure describes aspects of a framework, including: (1) QCL relationship applicability and notice; (2) unifying the signaling mechanism of the TCI state; (3) TCI status/TRP association; (4) beam application time definition; (5) default beam notes; (6) dynamic switching between single TRP operation and multiple TRP operation; (7) a unified TCI state for CG/SPS based transmissions; and (8) a Beam Fault Recovery (BFR) mechanism with unified TCI status.

QCL relationship applicability and attention

For DL transmission, the supported source RSs for multi-TRP transmission of the unified TCI may include CSI-RSs for tracking, CSI-RSs for beam management, and CSI-RSs for CSI. For UL transmission, the supported resource RSs for multi-TRP transmission of the unified TCI may include SSB, CSI-RS, and SRS, not limited to beam management use. In some embodiments, SSBs and SRS may be excluded from the source RS list for DL transmission.

In some embodiments, the maximum number of configured TCI states in a multi-TRP transmission for joint DL/UL TCI states may be per BWP or per CC 128, and the candidate value for the number of configured TCI states may be per BWP or per CC 64 and 128 for DL and per BWP or per CC 32 and 64 for UL. The joint DL/UL TCI state may share the same pool, while a separate pool may be configured for UL TCI state. Further, multiple sub-pools may be configured within each of the joint pool/DL pool and UL pool corresponding to different TRPs. Each sub-pool may contain a set of resources, where the set of resources corresponds to transmissions to/from a particular TRP and shares the same TCI state.

The supported target channels and target RSs for multi-TRP DL transmissions sharing the same indicated unified TCI state may be UE-specific PDCCH/PDSCH, non-UE-specific PDCCH/PDSCH associated with serving cell PCI, aperiodic CSI-RS resources for CSI, and aperiodic CSI-RS resources for beam management. In some embodiments, periodic CSI-RS resources and semi-persistent CSI-RS resources may be excluded from the DL target RS list to allow beam measurement and CSI reporting for different candidate beams in a unified TCI state before switching to those different candidate beams.

The power control parameters and path loss RS for the target UL channel and target RS may be associated with the UL TCI state or joint TCI state of each BWP via RRC configuration independently for each of UL channels PUCCH, PUSCH, and SRS. If multiple unified TCI states (e.g., at most one unified TCI state per TRP) may be indicated for multi-TRP transmission, each of the indicated UL TCI states or joint TCI states may be associated with a set of power control parameters and path loss RSs for each UL target channel per BWP corresponding to one particular TRP. If only a single common unified TCI state is indicated for all TRPs in a multi-TRP transmission, then multiple sets of power control parameters and path loss RSs may be associated with the commonly indicated UL TCI state or joint TCI state.

Signaling mechanism for unifying TCI states

In some embodiments, UE-specific DCI with or without PDSCH allocation (e.g.For example, DCI format 1_1 or DCI format 1_2) may be used as a signaling medium in multi-TRP transmission to update the unified TCI state. The unified TCI state may be indicated by a single code point in the TCI field of the DCI, where the TCI state/code point mapping is provided by the MAC CE command. The MAC CE code point map may associate multiple unified TCI states (e.g., multiple joint DL/UL TCI states, multiple pairs of DL TCI states and UL TCI states, or multiple joint DL/UL TCI states and multiple pairs of DL TCI states and UL TCI states in combination) with a single code point. To illustrate, for multi-TRP transmission with M TRPs, in the case of a single DCI scheme, up to M unified TCI states may be mapped to one code point in the MAC CE, where M may be present ₁ Individual joint DL/UL TCI states and M ₂ For DL TCI state and UL TCI state such that m=m ₁ +M ₂ . With a k-bit TCI field, up to 2 can be signaled in a single DCI transmission representing both single-TRP and multi-TRP transmissions ^k Code points (i.e., TCI status scenes). In some embodiments, there may be multiple TCI fields (i.e., one TCI field per TRP) in the DCI, where the unified TCI state of each TRP may be indicated by a separate code point in the corresponding TCI field of that TRP of the DCI.

To illustrate, for multi-TRP transmission with M TRPs, up to M individual code points may be indicated in up to M TCI fields in the DCI in the case of a single DCI scheme. TCI state/code point mapping may be provided in the MAC CE command. An advantage of this proposed scheme is that DCI interpretation will be easier because each field can be interpreted separately for each TRP transmission. For the overall available TCI status indication in this scheme, a total of up to 2 may be signaled for multi-TRP transmission only, with k bits and two TRPs for each TCI field ^2k There are several possible combined code points, but some embodiments may reserve one code point as an indicator of a single TRP transmission to the UE. Thus, the multi-TRP transmission may have as many as (2 ^k -1) ² Each possible combined code point and each single TRP transmission may have up to 2 ^k -1 possible code point to be signaled. That is, in the case of the proposed scheme of a TCI field separate for each TRP, the signaling can be used in a single DCI transmissionNumber transmission for both single and multiple TRP transmissions up to a total of (2 ^k -1) ² +2(2 ^k -1)＝2 ^2k -1 combined TCI status scenario. Comparing the TCI field scheme of each TRP with a single TCI field scheme of the same bit length (i.e., 2 kbit), in which the total available code point to be signaled is 2 ^2k While the total available code point at which the TCI field scheme for each TRP will be signaled is 2 ^2k -1。

In some embodiments of the single field scheme, a TRP indication/index may be added to each code point MAC CE for single TRP transmission. As an example, for a MAC CE without TRP indication, TCI state id_ { x, y } for code point x may be used. When the code point includes two TRPs, there may be two TCI IDs in the case of y=1 and y=2. When the code point includes one TRP, there may be only one TCI ID in the case of y=1. However, since there will be no indication about the associated TRP, some embodiments may add a TRP indication after a TCI ID when there is only one TCI ID.

For some embodiments of the multi-DCI scheme, each DCI may follow a code-point mapping design, where each code point represents one unified TCI state (e.g., a joint DL/UL TCI state, or a pair of DL TCI states and UL TCI states, or DL TCI state only, or UL TCI state only). In some embodiments of a unified design scheme for both single DCI schemes and multiple DCI schemes in a multi-TRP transmission, the indicated code points in the TCI field of the DCI may represent all unified TCI states of the multi-TRP transmission. With this unified solution, a single TCI state association design may be applicable to both single DCI and multiple DCI schemes. The unified solution would allow cross-TRP beam activation in a multi-DCI scheme without additional DCI overhead, support that some of the DCIs do not have TCI fields, and facilitate the same unified beam application time definition as that of single TRP transmission.

For multi-TRP transmissions, common TCI state updates and activations across a set of configured CCs may also be supported. In this scenario, the source RS for QCL-type A (QCL-TypeA) or QCL-type B (QCL-TypeB) may be in the same CC/BWP as the target channel or target RS. Furthermore, the unified TCI state for activation of multi-TRP transmissions may be directly or indirectly associated with PCI(s) other than serving cell PCI, in which case more than one active TCI state or dynamic switching of TCI states per band of UEs for inter-cell transmission (e.g., via MAC CE) may be supported.

In some embodiments, the application of a unified TCI state for the PDCCH in the multi-TRP transmission and the indication of the corresponding PDSCH reception may be determined for the RRC configuration of each CORESET. For the single DCI scheme or the unified design scheme proposed above for both the single DCI scheme and the multiple DCI scheme (i.e., one code point is mapped to an all TRP unified TCI state), the application of all multi-TRP unified TCI states received by all PDCCHs and PDSCHs may be based on the RRC configuration of the corresponding CORESET. For a multi-DCI scheme with a uniform TCI status indication for each TRP, the indicated TCI status may be applied separately for each TRP based on each TRP's own CORESET configuration. In some embodiments, the UE may apply the unified TCI state for the PDCCH and the indication of the corresponding PDSCH reception on CORESET associated with only UE-specific reception (except CORESET # 0).

For any SRS resource or set of resources that may be configured as a target signal for a uniform TCI state but not applying the indicated uniform TCI state, UL power control parameter settings including the pathloss RS should be derived based on the settings associated with the indicated uniform TCI for SRS resources with the lowest ID in the SRS resource set. The power control parameters (e.g., P0, alpha, closed-loop index) and path loss RS for the target UL channel and RS may be associated with UL or joint TCI status for each BWP via RRC configuration. The power control parameter settings may be configured independently for each of UL channels PUCCH, PUSCH, and SRS.

TCI state/TRP association

In some embodiments, the association of indicated uniform TCI states with different TRPs may be used to determine which of the indicated uniform TCI states may be applicable to the target channel and target RS of a particular TRP. One semi-static solution applicable to both single DCI schemes and multi-DCI schemes may be based on resource grouping and sub-pool design context for each TRP, as previously described, where the sub-pool ID may be used as an implicit association of unified TCI status and TRP. In some embodiments, multiple resource groupings may be defined within each of the joint pool/DL pool and UL pool to represent sub-pools of each TRP, and each of these sub-pools may be associated with a sub-pool ID, where the sub-pool ID may be used as an implicit indication of the association between a particular TRP and the indicated unified TCI state.

In some embodiments, a semi-static configuration may be used to explicitly indicate a unified TCI state/TRP association. To illustrate, each target channel and target RS may have a particular RRC parameter configuration to indicate an association with a particular indicated unified TCI state (or a particular TRP). The RRC parameter may use a vector bit or bitmap structure to indicate a uniform TCI state to be applied to a specific indication of the target channel and/or target RS. As an example, for multi-TRP operation with two TRPs, two-bit RRC parameters may be configured for each target channel (e.g., PDCCH/PDSCH and/or PUCCH/PUSCH) and/or target RS (e.g., CSI-RS and/or SRS). The configured value "01" may represent the uniform TCI state of the first indication, the configured value "10" may represent the uniform TCI state of the second indication, and the configured value "11" (or "00") may represent the uniform TCI state of the first indication and the uniform TCI state of the second indication to be applied to the target channel and/or target RS. The determination of the first indicated unified TCI state and the second indicated unified TCI state may be based on an order of the TCI states indicated in the DCI (e.g., in a TCI field scheme of each TRP), on a code point mapping in the MAC CE (e.g., in one TCI field scheme), or on an order of the TCI state IDs.

For SRS as a target resource, a new RRC parameter configuration (similar to the legacy spatialreactioninfo) may be added at the resource level to indicate an implicit or explicit association with a specific indicated unified TCI state or a specific TRP. To illustrate, as an explicit way, the association of RRC configurations may be indicated by pointing to a unified TCI state ID. In some embodiments, as an implicit way, association of RRC configurations may be indicated (e.g., in two TRP operations) by a vector bit or bitmap format indication of the first indicated unified TCI state, the second indicated unified TCI state, or both indicated unified TCI states. For CSI-RS as a target resource, a new RRC parameter configuration may be added at the resource level to indicate an implicit or explicit association with a specific indicated unified TCI state or a specific TRP. To illustrate, as an explicit way, the association of RRC configurations may be indicated by pointing to a unified TCI state ID (similar to qcl-infosperiodicsl-RS for periodic CSI-RS resources). In some embodiments, as an implicit way, association of RRC configurations may be indicated (e.g., in two TRP operations) by a vector bit or bitmap format indication of the first indicated unified TCI state, the second indicated unified TCI state, or both indicated unified TCI states.

In some embodiments, the UE may identify the unified TCI state/TRP association using a predetermined rule such that the order of TCI state IDs, code point mapping in the MAC CE, or the order of TCI states (e.g., minimum/maximum/specific ID or minimum/maximum/specific TCI state) is based on the order of target resource IDs. For example, the unified TCI state of the first indication may be applied to the target resource with the smallest target resource ID. Another specific way to adapt to a single DCI scheme with repetition is to implicitly associate each indicated unified TCI state to one repetition occasion based on a predetermined rule. For example, the UE may map the indicated unified TCI state to the repetition occasion according to the order of TCI state IDs, code point mapping of MAC CE commands, or the order of TCI states. For the multi-DCI scheme, coresetpoolndex may be used as an implicit association of unified TCI status and TRP. For example, the unified TCI state for each indication may be activated by a MAC CE for the coresetpoolndex, and all scheduled channels and signals of the DCI may also be associated with a particular coresetpoolndex. Thus, the corresponding TRP for the unified TCI state for each indication may be determined based on coresetpoolndex.

In some embodiments, the gNB may provide the association to the UE in DCI or MAC CE command for dynamic TCI state/TRP association configuration and/or dynamic TCI state/TRP association update. A new field may be introduced in the DCI or MAC CE or other existing fields may be reused to indicate the TCI status/TRP association by a vector bit format or bitmap format. Even with an indication of a single unified TCI state in the DCI, such TCI state/TRP associated fields may be present in the DCI, which would allow unified TCI state updates for the target channel and target RS. For example, if the target SRS/CSI-RS resource is RRC configured to follow the first indicated unified TCI state, the dynamic TCI state association in the DCI to the first indicated unified TCI state and the single indicated unified TCI state indication will update the TCI state of the target resource. The TCI state/TRP association indication in the DCI may also implicitly indicate dynamic switching between single TRP transmission and multi TRP transmission.

When the scheduling offset is less than the timeduration for qcl threshold, the UE may follow a default TCI state/TRP association to determine whether one or more uniform TCIs are applied to the target channel and target RS including the scheduled PDSCH, and also to determine which TRP (or TCI associated with such TRP) to apply if one uniform TCI is applied. In RAN1 conference #112, this problem is discussed and a protocol is reached that addresses the UE behavior in the following cases: the UE supports the ability to two default beams for single DCI based multi-TRP transmission or otherwise assumes that the offset between the reception of the scheduled DCI and the scheduled PDSCH is equal to or greater than timeduration for qcl. However, this protocol does not address the scenario where the UE does not support the capability of two default beams and the gap between DCI and scheduled PDSCH is less than timeduration forqcl.

When the UE does not support the capability of two default beams and the gap between DCI and scheduled PDSCH is less than timeduration forqcl, one possible solution is to apply predefined rules or RRC indication or MAC CE indication to provide default TRP association. In some embodiments, the default TCI state/TRP association may be defined as following a previously indicated TCI state/TRP association in DCI most recently received and/or Acknowledged (ACK) by the UE for a specific/preconfigured duration per symbol or slot from the scheduled PDSCH, as shown in fig. 2. When the offset between the scheduling DCI 201 and the PDSCH 202 of interest is less than timeduration forqcl and the offset between the previous DCI 203 and the PDSCH 202 is greater than timeduration forqcl, the behavior shown follows the TCI state/TRP association of the most recently received DCI 203 in the latest time slot (i.e., the scheduled PDSCH time slot).

Fig. 3 illustrates another possible association behavior when the offset between the scheduling DCI 301 and the PDSCH 302 of interest is less than timeduration forqcl and the offset between the previous DCI 303 and the PDSCH 302 is greater than timeduration forqcl, according to an embodiment. The behavior shown follows the TCI state/TRP association of the DCI 303 that was most recently received and ACK within K symbols preceding the scheduled PDSCH starting symbol. The value of K can be limited to be less than the maximum beam application time BAT in the unified TCI framework _max (i.e., K.ltoreq.BAT) _max ) To ensure a uniform TCI state for similar indications of scheduled PDSCH and the above-mentioned recent DCI. The value of K may be UE capability.

Fig. 4 illustrates another possible association behavior when the offset between the scheduling DCI 401 and the PDSCH 402 of interest is less than timeduration forqcl and the offset between the previous DCI403 and the PDSCH 402 is greater than timeduration forqcl, according to an embodiment. The behavior shown follows the TCI state/TRP association of the DCI403 that was most recently received and ACK within K slots preceding the latest slot (i.e., the scheduled PDSCH slot). The value of K may be UE capability.

Another possible solution is that the gNB may indicate to the UE a reference CORESET among CORESETs configured within the same time slot as the scheduled PDSCH (i.e., the latest time slot) or within an activated BWP of the serving cell monitored by the UE within any particular/preconfigured duration in terms of symbols or time slots from the scheduled PDSCH. The default TCI state/TRP association may then be determined/provided based on the TCI state association of the reference CORESET. The reference CORESET may be the CORESET closest to the PDSCH starting symbol within the slot. The reference CORESET may be the CORESET having the lowest or predetermined CORESET ID among CORESETs monitored by the UE in the latest slot. The reference CORESET may be the CORESET with the lowest or predetermined CORESET ID among the CORESETs monitored by the UE within a specific/preconfigured time slot (by symbol or slot) from the scheduled PDSCH. The specific/preconfigured time slot may be UE capability.

The UE may also need to follow a default TCI state/TRP association when there is no TCI state/TRP association indication field in the DCI. This problem is discussed in RAN1 conference #112 and an agreement is made to address the following: the offset between reception of the scheduling DCI (e.g., DCI format 1_1/1_2) and reception of the scheduled/activated PDSCH is equal to or greater than a threshold. When the UE supports the capability of two default beams for single DCI based multi-TRP transmission and there is no TCI status/TRP association indication field (also may be referred to as "TCI select field") in the DCI, the protocol applies regardless of the threshold. That is, the UE may buffer the received signal before the threshold using the two indicated unified TCI states and apply the protocol rule(s) after the threshold. However, when the gap between DCI and scheduled PDSCH is less than timeduration forqcl and the UE does not support the capability of two default beams for single DCI based multi-TRP transmission, the UE behavior is not addressed. To address this issue, our previous discussion and proposed solutions for default TCI state/TRP association also apply when no TCI state/TRP association indication field is present in the DCI and the scheduling offset is less than the timeduration for qcl threshold. These solutions include using predefined rules, RRC indications, or MAC CE indications, which follow the association of previous indications in DCI recently received and/or ACK by the UE within a specific/preconfigured duration per symbol or slot from the scheduled PDSCH, and follow the association of reference CORESETs among CORESETs monitored by the UE within a specific/preconfigured time slot (per symbol or slot) from the scheduled PDSCH.

Regarding dynamic switching between single TRP transmission and multiple TRP transmission, in some embodiments, dynamic switching flexibility of the gNB may be limited when there is no TCI status/TRP association indication field in the DCI and the UE will not desire dynamic switching between single TRP transmission and multiple TRP transmission. In some embodiments, even when there is no TCI state/TRP association indication field in the DCI, the flexibility of dynamic switching of the gNB between single TRP transmission and multi TRP transmission may not be limited, in which case the dynamic switching may be implicitly determined by the number of unified TCI states mapped to the code points in the TCI field. The default TCI state/TRP association may then be determined based on predefined UE behavior rules as follows:

if the current scheduling DCI indicates a code point with two unified TCI states, the UE applies the two unified TCIs.

One possible solution is that only the first reference TCI state or the pre-configured reference TCI state indicated by the RRC configuration or MAC CE may be used if the current scheduling DCI indicates a code point with one unified TCI state. For example, the pre-configured reference TCI state may be RRC configured along with an RRC configuration without a TCI state association indication field in the DCI. Another flexible alternative solution is to follow the latest DCI or reference CORESET indicating one of the unified TCI states (as discussed in detail above). To illustrate, a default TCI state/TRP association may be determined/provided based on the TCI state association of the lowest or predetermined CORESET ID among a plurality of CORESETs having a single TCI state association and being in the most recent slot or at a particular distance from the scheduled PDSCH

Monitored by the UE for a preconfigured duration.

One solution is to apply two unified TCIs if there is no TCI status field in the currently scheduled DCI. Alternatively, the default TCI state/TRP association may be determined/provided according to predefined rules or RRC indications or MAC CE indications of one of the TCI states. Alternatively, the default TCI state/TRP association may be defined as following a previously indicated TCI state/TRP association in the DCI most recently received and/or acked by the UE for a specific/preconfigured duration per symbol or slot from the scheduled PDSCH. Alternatively, the default TCI state/TRP association may be determined/provided from the TCI state association of the lowest or predetermined CORESET ID among CORESETs monitored by the UE in the latest time slot or within a specific/preconfigured duration from the scheduled PDSCH.

Any combination of two UE behavior rules (rule #1 and rule # 2) selected from the above-described rules may be used to apply the indicated unified TCI state(s) to the scheduled/activated PDSCH corresponding to any of the following two scenarios:

ue does not support the capability of two default beams and the gap between the scheduling DCI and the scheduled/activated PDSCH is less than timeduration forqcl.

Ue does not support the capability of two default beams, the gap between the scheduling DCI and the scheduled/activated PDSCH is less than timeduration forqcl, and there is no TCI select field in the scheduling DCI.

For selection rule #1 to address scenario I and selection rule #2 to address scenario II above, if the granularity at which the TCI selection field exists is defined for each CORESET, this may result in UE behavior ambiguity as to how the indicated unified TCI state(s) are applied to the scheduled/activated PDSCH. To better illustrate, such UE ambiguity occurs because the UE may be configured with multiple CORESETs to be monitored within timeduration forqcl from the starting symbol of the scheduled PDSCH (where each CORESET may be associated with a different presence configuration of the TCI select field). Therefore, the UE will not know which rule (i.e., rule #1 or rule # 2) should be applied before the decoding of the scheduling DCI is completed. That is, because the presence configuration of the TCI select field is for each CORESET, rule selections will be associated with CORESETs. Fig. 5 shows an example of ambiguity that occurs when the gap between the scheduling DCI 501 and the scheduled/activated PDSCH 502 is less than timeduration forqcl and the UE does not support the capability of two default beams. There are two CORESETs that the UE blindly monitors: CORESET I503 with a configuration of TCI select field "present"; and CORESETI I504 having a configuration of TCI select field "none present". In this example, the UE has ambiguity as to whether rule #1 or rule #2 is applied to the TCI association of the scheduled PDSCH 502.

To address this ambiguity, one solution may be to determine that the granularity at which the TCI state select field exists is the same for all CORESETs. Another solution is to prevent this multi-rule behavior and the resulting ambiguity by enforcing the same UE behavior rules for: for both scenario I and scenario II previously described, the indicated unified TCI state(s) are applied to the scheduled/activated PDSCH. For example, the gNB may indicate to the UE a reference CORESET among CORESETs configured within the same time slot as the scheduled PDSCH (i.e., the latest time slot) or within an activated BWP of the serving cell monitored by the UE within any particular/preconfigured duration per symbol or time slot from the scheduled PDSCH. The default TCI state/TRP association may then be determined/provided based on the TCI state association of the reference CORESET. As shown in fig. 6, the reference CORESET 601 may be the CORESET within the slot closest to the starting symbol of the PDSCH 602. As shown in fig. 7, the reference CORESET 701 may be the CORESET having the lowest or predetermined CORESET ID among CORESETs monitored by the UE in the latest slot. As shown in fig. 8, the reference CORESET 801 may be the CORESET closest to the PDSCH 802 within the last K symbols. As shown in fig. 9, the reference CORESET 901 may be the CORESET with the lowest or predetermined CORESET ID among CORESETs monitored by the UE during a particular/preconfigured time slot (e.g., within K symbols or slots) within the last K symbols from the scheduled PDSCH 902. In some embodiments, the specific/preconfigured time slot may be timeduration forqcl instead of K symbols or slots, and the actions shown in fig. 6-9 may be similarly applied.

In single DCI based multi-TRP transmission, one PDSCH and one PDCCH may overlap in the time domain on one or more symbols. Under the previously established behavior, the UE is expected to receive both PDCCH and PDSCH when the overlapped PDSCH and PDCCH have the same TCI state, and to preferentially receive PDCCH when they have different QCL type D (QCL-type) in the two TCI states. However, there is no established UE behavior for the case where PDSCH and PDCCH overlapping in at least one symbol have the same uniform TCI state but have different TCI state/TRP associations. One solution is to receive preferentially the PDCCH with its corresponding TCI state/TRP association. Another alternative is to receive the PDCCH preferentially only for the corresponding transmission occasion of the different associated TCI state(s). To illustrate, consider the case where the TCI state/TRP association for PDCCH is two beams and the TCI state/TRP association for PDSCH is the first beam, then PDSCH reception is performed only for the first PDSCH transmission occasion (along with PDCCH reception) while PDCCH reception is prioritized at the second PDSCH transmission occasion. For the very first single DCI based multi-TRP transmission, when only one unified TCI state is indicated and applicable, a default beam may be determined based on the two TCI states of the lowest MAC CE code point among the MAC CE code points having two TCI states before BAT.

For semi-persistent and aperiodic SRS resources as target RSs, an example of a MAC CE-based association is by adding a new field or reusing an existing spatial relationship information field within the same MAC CE command used to activate/deactivate/update the semi-persistent/aperiodic SRS resources for association indication. Similarly, a new field may be introduced within the DCI to indicate the association of triggered SRS resources with indicated unified TCI state in a vector bit or bitmap format. For semi-persistent CSI-RS resources as target RS, the MAC CE-based approach may add a new field or reuse an existing TCI status field for association indication within the same MAC CE command used to activate/deactivate/update the semi-persistent CSI-RS resources. Additionally, a new field may be introduced within the DCI to indicate the association of CSI-RS resources with the indicated unified TCI state in a vector bit or bitmap format.

Beam Application Time (BAT) definition

The beam application time in a multi-TRP transmission may be defined in a collective (collective) manner in which all TRPs refer to one specific ACK transmission as a counting reference symbol, or in a per TRP manner in which each TRP refers to its corresponding TRP ACK transmission as a counting reference symbol for that TRP. To illustrate, for multi-TRP transmission in a single DCI scheme, a corresponding ACK transmission of the single DCI may be considered a time reference to define an application time of multi-TRP TCI state update as at least Y symbols after a last symbol of the ACK transmission. For multi-TRP transmission in a multi-DCI scheme, one potential solution may consist in defining a new beam application time for each TRP, where the indicated TCI state of each TRP is applied at least Y symbols after its own last symbol of the corresponding ACK transmission.

In some embodiments, as a unified design scheme for both single DCI schemes and multiple DCI schemes in a multiple TRP transmission, a UE may determine one of the TRPs and/or a unified TCI state corresponding to the one TRP as a reference TRP and/or a reference unified TCI state in the multiple DCI scheme, wherein a corresponding ACK of the reference TRP and/or the unified TCI state may be used to define a new beam application time. The reference TRP and/or unified TCI state may be semi-statistically configured or dynamically indicated/updated to the UE, or some embodiments may use specific rules to indicate the reference TRP and/or unified TCI state, such as CORESETPoolIndex, TCI state pool index, TCI state ID, or even the (e.g., minimum, maximum, first, specific) order of source resource IDs based on the indicated TCI state. In some embodiments, the beam application time may be defined as at least Y symbols after a last symbol of a last ACK among all ACKs corresponding to the plurality of DCIs. In all of the above schemes, if the MAC CE activates only a single TCI code point, the new beam application time may follow the rel.16 application timeline for MAC CE activation.

In some embodiments, for both single TRP transmission schemes and multi TRP transmission schemes, the unified TCI state(s) indicated by the scheduling DCI may be applied to the reception of the scheduled PDSCH (even before the beam application time) when the scheduling offset between the scheduling DCI and the scheduled PDSCH is greater than the timeduration forqcl threshold. Fig. 10 shows an example of this behavior, in which a beam to be used for receiving the PDSCH 4 (1002) is the TCI state (F, G) indicated by the scheduling multi-TRP DCI 4 (1001), and a beam to be used for receiving the PDSCH 6 (1004) is the TCI state (I) indicated by the scheduling single TRP DCI 6 (1003). For any other target channel/RS, the UE may apply these indicated unified TCI state(s) after the beam application time, as previously discussed.

Default beam notes

Ambiguity with respect to the default beam for transmission may occur when the TCI field is not present in the DCI for the multi-TRP transmission. In some embodiments, when the TCI field is not present in the DCI of the multi-TRP transmission, the default beam may be determined based on the TCI state of the lowest MAC CE code point among the MAC CE code points having two TCI states. Extending a unified TCI framework for multi-TRP transmission, for a single DCI scheme or for a multi-DCI scheme with the same single code point indication across all TRPs (i.e., a single code point maps to all unified TCI states), a UE may determine a default unified TCI state as the TCI state of the lowest MAC CE code point among MAC CE code points mapped to multiple unified TCI states (e.g., multiple joint DL/UL TCI states, multiple pairs of DL TCI states and UL TCI states, or multiple joint DL/UL TCI states and multiple pairs of combinations of DL TCI states and UL TCI states). In some embodiments, for a multi-DCI scheme, if any other corresponding DCI exists a TCI field, the default beam may be determined by the indicated unified TCI state of that DCI. In a multi-DCI scheme with a code point indication design for each TRP alone, a default beam may be determined based on the TCI state of the lowest CORESET index among CORESET indexes configured with a uniform TCI state.

Another UE beam ambiguity that may occur is when the scheduling offset is less than the timeduration forqcl threshold. In rel.17, as previously explained, the UE behavior for single TRP transmissions is that the UE follows the indicated TCI state (for both non-UE-specific PDSCH and UE-specific PDSCH) for intra-cell transmission and the UE follows the rel.16 behavior (for both non-UE-specific PDSCH and UE-specific PDSCH) for intra-cell transmission.

The rel.16ue behavior for determining the default beam when the scheduling offset is less than the timeduration forqcl threshold is based on the following:

the TCI state of the lowest CORESET index for single TRP transmission,

the TCI state of the lowest MAC CE code point among the MAC CE code points mapped to the plurality of TCI states for a single DCI scheme in multi-TRP transmission,

the TCI state of the lowest CORESET index associated with the value of coresetpolindex for the multi-DCI scheme in multi-TRP transmission.

In some embodiments, the maximum rank (i.e., maxnumbermmo-LayersPDSCH) supported and reported to the gNB by the UE is shared for both multi-TRP and single-TRP transmissions. When the scheduling offset is less than the timeduration for qcl threshold in a multi-TRP transmission scheme with two TRPs, the UE may apply two beams to PDSCH reception from the two TRPs, following the rel.16 default beam rule. Then, when scheduling single TRP transmission, some layers of the PDSCH may be received with one of the default beams (i.e., the beam corresponding to the transmitting TRP) and the remaining layers may be received with the other beam (i.e., the beam corresponding to the non-transmitting TRP), resulting in significant performance loss.

In other words, when the scheduling offset is less than the timeduration fortcl threshold in the multi-TRP transmission scheme, if only one TRP PDSCH is scheduled, the UE may support only half of the maximum rank reported. To address this issue, in some embodiments, when the scheduling offset is less than the timeduration for qcl threshold, the maximum transmission rank per single TRP transmission may be limited to half the value reported in maxnumbermmo-LayersPDSCH for multi TRP transmission.

For multi-TRP transmission of single DCI, a default beam rule may be employed given that the gNB will not schedule single TRP transmission of single DCI when the scheduling offset is less than the timeduration forqcl threshold. However, for multi-TRP transmission of multi-DCI, the above rank restriction may need to be defined to avoid applying an erroneous beam to PDSCH reception. To address this issue, when the scheduling offset may be less than the timeduration for qcl threshold, the maximum transmission rank per single TRP transmission may be limited to half of the maximum rank supported by the UE (as reported in maxnumbermmo-LayersPDSCH) for multi TRP transmission. Hereinafter, "M" in the table indicates whether the associated feature is mandatory (or not), wherein the associated feature is mandatory when "M" is "yes" and optional when "M" is "no". More specifically, this can be achieved as follows:

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Since the above approach is related to existing parameters, it does not allow an explicit indication of the maximum number of layers. Thus, in some embodiments, the maximum number of MIMO layers for PDSCH as UE capability in this case may be as follows:

the above capability can be extended as follows to cover the aforementioned single DCI multi-TRP unified TCI case:

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extending the unified TCI framework for multi-TRP transmission, some embodiments may first address an intra-cell only transmission scenario in which all indicated TCI states may be associated with the serving cell PCI. In such a scenario, if the scheduling offset is greater than the timeduration for qcl threshold, the UE may apply the indicated unified TCI state to PDCCH and corresponding PDSCH reception. If the scheduling offset is less than the timeduration forqcl threshold in an intra-cell only transmission scenario, the UE may use the indicated TCI(s) for any PDSCH reception (i.e., both UE-specific PDSCH and non-UE-specific PDSCH) for a multi-TRP transmission scheme of single DCI, and may not need default beam notes. Note, however, that this is assuming that the gNB does not schedule dynamic switching between single and multiple TRP transmissions in the single DCI scheme when the scheduling offset is less than the timeduration forqcl threshold. In other words, when the scheduling offset is less than the timeduration forqcl threshold, a single TCI code point is not indicated by DCI in the TCI field scheme of each TRP, or a code point mapped to a single TCI state in one TCI field scheme is not activated by MAC CE or indicated by DCI. In some embodiments, if the scheduling offset is less than the timeduration forqcl threshold in an intra-cell only transmission scenario, the UE may follow rel.16 behavior for both non-UE-specific PDSCH and UE-specific PDSCH for a single DCI multi-TRP transmission scheme and apply the TCI state mapped to the lowest MAC CE code point among the MAC CE code points of the multiple unified TCI states. The solution also has the following assumptions: when the scheduling offset is less than the timeduration forqcl threshold, the gNB will not schedule single TRP transmissions of a single DCI (i.e., a single TCI code point is not indicated by DCI in the TCI field scheme of each TRP) or the code points mapped to a single TCI state (in one TCI field scheme) are neither co-located nor indicated by DCI.

Another alternative when the scheduling offset is less than the timeduration forqcl threshold may follow the default TRP association. For example, there may be predefined rules, RRC indications, or MAC-CE indications to provide default TRP associations. Such rules or directives determine whether one or more TCIs are applied to the scheduled PDSCH and also which TRP (or TCI associated with such TRP) to apply if one TCI is applied. Another example of default association is an association to which a previous indication of DCI is applied, where the gap between such DCI and PDSCH of interest is greater than timeduration forqcl. If some embodiments allow flexibility in dynamic switching between single TRP transmission and multi TRP transmission when the scheduling offset is less than the timeduration forqcl threshold for the gNB applicable to both of the above proposed solutions, some embodiments may need to limit the maximum transmission rank per single TRP transmission to avoid applying wrong beams to receive some layers of PDSCH. To illustrate, if the UE supports a maximum rank of N for multi-TRP transmission, the maximum rank of any scheduled single TRP transmission may be limited to N/2 when the scheduling offset is less than the timeduration for qcl threshold. For the multi-DCI transmission scheme, similarly, when the scheduling offset is less than the timeduration forqcl threshold, with the flexibility of dynamic switching between single-TRP and multi-TRP transmissions with the gNB, the maximum transmission rank per single-TRP transmission may be limited to half the maximum rank that the UE supports for multi-TRP transmission (as reported in maxnumber mimo-LayersPDSCH).

Since the application of a unified TCI state for the PDCCH and the indication of the corresponding PDSCH reception may be determined for the RRC configuration of each CORESET, the definition of inter-cell transmissions in multi-TRP operation may be further clarified in some embodiments to further resolve ambiguity in the determination of TCI state for UEs when the scheduling offset is less than the timeduration forqcl threshold.

For multi-TRP transmission of multi-DCI, the inter-cell determination may be based on the pool index of each CORESET following the same pool index mechanism of each CORESET for default beam determination. To illustrate, it is possible that the indicated uniform TCI state for coresetpoolndex 0 is intra-cell (i.e., the indicated TCI state is associated with a serving cell PCI) and the indicated uniform TCI state for coresetpoolndex 1 is inter-cell (i.e., the indicated TCI is associated with a PCI different from the serving cell PCI). For intra-cell transmission, the UE may apply the indicated TCI state in CORESET with coresetpolindex 0. For inter-cell transmission, the UE may apply the TCI state of the lowest CORESET ID in the latest slot in CORESET with coresetpolindex 1.

Another way to define inter-cell transmissions in a multi-DCI multi-TRP transmission scenario may be where at least one of the inter-cell transmissions is defined as TRPs is indicated with a TCI state associated with the serving cell PCI (i.e., intra-cell), and the gNB is most likely to transmit non-UE-specific PDSCH only from TRPs within at least one particular cell. For a particular TRP or some CORESET Chi Suoyin (which may be predetermined for the UE, or semi-statically configured, or dynamically (MAC CE/DCI) indicated), the UE may follow a unified TCI, regardless of inter-cell or intra-cell transmission, because the unified TCI is associated with the UE-specific PDSCH. In some embodiments, the particular TRP or some CORESET pool index may be indicated implicitly to the UE. To illustrate, the same TCI state that the gNB configures all CORESETs in one coresetpoolndex to follow the indication is an implicit indication that the UE follows a unified TCI.

Another way for inter-cell determination in multi-TRP transmission of multi-DCI may be to define inter-cell transmission as the case where all indicated TCI states are associated with a PCI different from the serving cell PCI (i.e., transmissions from all TRPs may be inter-cell). With such a definition, the UE may apply the TCI state mapped to the lowest MAC CE code point among the MAC CE code points of the plurality of unified TCI states.

For multi-TRP transmission of a single DCI or for the proposed multi-DCI scheme with the same single code point indication across all TRPs, some embodiments may define inter-cell transmission in multi-TRP operation as the case where at least one of the states of the multiple indications is associated with a PCI different from the serving cell PCI. In this case, it is possible that an inter-cell transmission may be scheduled from this CORESET, which may result in similar beam ambiguity as in rel.17, especially when there may be other CORESETs that may be configured to not follow the indicated unified TCI state. To address this problem, some embodiments may consider it unlikely to have a non-UE-specific PDSCH for multi-TRP transmissions. Thus, only a specific TRP may transmit a non-UE specific PDSCH, and the specific TRP may be indicated to the UE either explicitly (i.e., through RRC/MAC CE/DCI) or implicitly. Thus, the determination of the inter-cell transmission may be defined as a case where only the particular TRP has been indicated with a TCI state associated with a PCI different from the serving cell PCI.

In some embodiments, the inter-cell determination in multi-TRP transmission of single DCI may be considered as the case where all indicated TCI states are associated with a PCI other than the serving cell PCI (i.e., the transmission from all TRPs may be inter-cell) assuming that the gNB will implicitly use the intra-cell TRP to transmit non-UE specific PDSCH when one of the indicated TCI states is associated with the serving cell PCI (i.e., is intra-cell). With such a definition, the UE may apply the TCI state mapped to the lowest MAC CE code point among the MAC CE code points of the plurality of unified TCI states. Further, since the UE will not know whether the scheduled PDSCH is single or multi-TRP before completing decoding of the DCI, some embodiments may define default beam rules for all CORESET in all cases since the UE applies the TCI state of the lowest MAC CE code point among the MAC CE code points mapped to multiple unified TCI states to both non-UE-specific PDSCH transmissions and UE-specific PDSCH transmissions.

Note that all the default beam notes presented above also apply to the default beam determination of aperiodic CSI-RS resources.

Dynamic switching between single TRP operation and multiple TRP operation

Depending on the target application scenario, the gNB may switch between single TRP transmission and multiple TRP transmission, e.g., to provide high reliability/coverage (e.g., for cell edge or high mobility scenarios) or high throughput (e.g., for cell center or low mobility scenarios). In the current specification, for a multi-TRP transmission scheme of a single DCI, the indicated code point of the MAC CE command may be mapped to one TCI state or multiple TCI states to allow dynamic switching between single TRP transmission and multi TRP transmission. For one TCI field scheme as described previously, dynamic switching between single TRP transmission and multi TRP transmission may be implicitly possible based on the number of unified TCI states associated with the indicated code point of the DCI. For the TCI field scheme of each TRP as described previously, dynamic switching between single TRP transmission and multi TRP transmission may be implicitly possible based on the TCI status/TRP association indication in the DCI. In both schemes, an implicit dynamic handover indication may also be used as an implicit indication to determine the receive beam for any corresponding PDSCH.

Depending on the UE capability, the UE may maintain activation as an active/current TCI state set with the indicated unified TCI state of a single TRP and the indicated unified TCI state of multiple TRP at the same time. Fig. 11 illustrates an example of such UE behavior, wherein at each time instance, the UE may maintain multiple indicated unified TCI states (e.g., a set of unified TCI states for a single TRP and unified TCI states for multiple TRPs) active. Both the two TCI states (A, B) indicated by DCI 1 (1101) and one TCI state (C) indicated by DCI 2 (1102) may remain active at the UE simultaneously as an active/current set of TCI states, and the UE may implicitly determine the beam to be used for PDSCH 3 (1113) reception based on the TCI code point of the respective scheduled DCI 3 (1103). That is, the number of TCI states mapped to the indicated TCI code point of the scheduling DCI may be an implicit indication to the UE whether the two TCI states (A, B) previously indicated and currently activated or one TCI state (C) previously indicated and currently activated are used for the corresponding PDSCH 3 reception during the beam application time of the DCI 3.

By defining some default UE behavior rules accordingly, the solution presented above can be generalized to address more complex scenarios and possible beam ambiguity scenarios. For multi-TRP transmission of single DCI, a given UE maintains a currently active set of TCI states including a configuration of a plurality of single TRP's unified TCI states and a configuration of a plurality of single TRP's unified TCI states, one possible ambiguity may be how the UE will maintain and update the currently active unified TCI state set (e.g., whether the newly indicated unified TCI state of the plurality of TRP's may override the corresponding previously indicated and activated unified TCI state of the single TRP, or vice versa).

Fig. 12 illustrates another example of UE behavior when TCI states are applied based on an active/current TCI state set. DCI 4 (1204) schedules PDSCH4 (1214). Although DCI 4 indicates a TCI state of multiple TRP (E, F), since PDSCH4 is scheduled for reception before applicable BAT, the indicated TCI state of multiple TRP (E, F) may not be used for reception of PDSCH 4. Instead, the UE may apply the configuration of the active/current TCI state set corresponding to the type of TCI state indicated. In the case of DCI 4 indicating a TCI state of a multi-TRP, the UE may apply a configuration of an active/current TCI state set corresponding to the TCI state of the multi-TRP.

Fig. 12 also illustrates the concept of associated TRP for each single TCI status indication (e.g., DCI 2 (1202), DCI3 (1203), DCI 5 (1205)). Such TRP association may be established by following the TRP association for DCI reception.

As previously described, when indicating the unified TCI states of multiple TRPs to the UE, it may also be desirable to indicate to the UE the association of those indicated unified TCI states with different TRPs so that the UE can determine which of the indicated unified TCI states applies to the transmission of a particular TRP. With the TCI/TRP association assumption where TCI1 may be associated with TRP 1 transmissions and TCI2 may be associated with TRP2 transmissions under the indicated unified TCI state of multiple TRPs (TCI 1, TCI 2), there may be ambiguity at the UE regarding the unified TCI state of an activated single TRP and the unified TCI state of multiple TRPs (i.e., configuration of the activated/current TCI state set) while PDSCH 3 and PDSCH4 are received. This problem can be solved by the following various statistical embodiments or schemes:

Scheme I: in some embodiments, the UE may maintain and update the active/current unified TCI state set for single TRP operation and multi TRP operation as separate configurations, and the active/current unified TCI state in each of these configurations (e.g., TRP1, TRP2, or multi TRP) may be updated separately with only DCI and corresponding TRP with the same type of transmission scheme. For example, the uniform TCI state configuration for the already indicated and activated/current single TRP of TRP1 may be updated with only the single TRP DCI corresponding to TRP1 (i.e., the indicated code point is mapped to the single TCI state corresponding to the respective TRP). Similarly, the configuration for the unified TCI state of the already indicated and activated/current multi-TRP may be updated with only the multi-TRP DCI indicating the multi-TRP TCI state (i.e., the indicated code point is mapped to multiple TCI states). Under scheme I, the active/current unified TCI state (i.e., beam) statistics for the example of fig. 12 are as follows:

the beam for receiving PDSCH 4 (1214) is the TCI state (A, B) indicated by the multi-TRP DCI 1 (1201), and the beam for receiving PDSCH 5 (1215) is the TCI state D indicated by the single-TRP DCI 3 (1203).

Scheme II: in some embodiments, the UE may update the active/current TCI state set associated with each TRP with each new DCI indication, regardless of whether the transmission scheme is single or multiple TRP. For example, the uniform TCI state of an already indicated and activated/current single TRP of a TRP may be updated with a single TRP DCI specifying the TRP (i.e., with a single TCI state indicated by a code point) or with a multi-TRP DCI specifying a multi-TRP including the TRP (i.e., with one of the TCI states indicated by a code point according to the TRP association). Similarly, each of the already indicated and activated/current uniform TCI states of the multi-TRP may be updated with the multi-TRP DCI or single TRP DCI. Under scenario II, the active/current unified TCI state statistics for the example of fig. 12 are as follows:

The beam for receiving PDSCH 4 (1214) is the TCI state (C, D) indicated by single TRP DCI 2 (1202) and single TRP DCI3 (1203), and the beam for receiving PDSCH 5 (1215) is the TCI state F indicated by multi TRP DCI 4 (1204).

The statistics of scheme II can be reduced to the following:

that is, the active/current TCI state set may maintain a configuration of TCI states for each single TRP, and may not require maintaining a separate configuration of TCI states for multiple TRPs.

Scheme III: in some embodiments, the UE may update the active/current single-TRP TCI state with each new DCI indication, regardless of the single-TRP transmission scheme or the multi-TRP transmission scheme, while the active/current multi-TRP TCI state may be updated with only the new multi-TRP DCI indication. Under scheme III, the active/current unified TCI state statistics for the example of fig. 12 are as follows:

the beam for receiving PDSCH 4 is the TCI state (A, B) indicated by the multi-TRP DCI 1 (1201), and the beam for receiving PDSCH 5 (1215) is the TCI state F indicated by the multi-TRP DCI 4 (1204).

Scheme IV: in some embodiments, the UE may update the TCI state of the active/current single TRP with only the new single TRP DCI indication, while the TCI state of the active/current multi TRP may be updated with each new DCI indication, regardless of single TRP transmission or multi TRP transmission. Under scheme IV, the active/current unified TCI state statistics for the example of fig. 12 are as follows:

The beam for receiving PDSCH 4 (1214) is the TCI state (C, D) indicated by single TRP DCI 2 (1202) and single TRP DCI3 (1203), and the beam for receiving PDSCH 5 (1215) is the TCI state D indicated by single TRP DCI3 (1203).

In the above example schemes, some embodiments only discuss unified TCI state determination for PDSCH transmission. However, these discussions may also apply to PDCCH/PUCCH/PUSCH transmissions, as the basic principles may be the same, and some embodiments may be preferred for a unified solution for all PDCCH/PDSCH/PUCCH/PUCSH transmission channels. Note, however, that for PDCCH and PDSCH, the DCIs in question DCI format 1_1 and DCI format 1_2, whereas for PUCCH and PUSCH, the aforementioned DCIs will be DCI format 0_1 or DCI format 0_2.

For the case where the UE is capable of maintaining only one single TRP activated's unified TCI state in addition to maintaining the unified TCI state of multiple TRPs activated, some embodiments may assume that the indicated unified TCI state of single TRP is applicable to any single TRP transmission, e.g., from TRP 1 or TRP 2. However, this may not be a practical assumption. Some embodiments may limit single TRP transmissions from only specific TRPs (i.e., single TRP transmissions for other TRPs may not occur). In the case of scheduling single TRP transmissions from other TRPs, some embodiments may limit beam determinations for those other TRPs to follow the rel.16 rule. In such a scenario, there may be ambiguity at the UE to update the active unified TCI state set. An example of such a scenario is shown in fig. 13.

Fig. 13 illustrates another example of UE behavior when TCI states are applied based on an active/current TCI state set. In the case of the TCI/TRP association hypothesis, where, in the indicated unified TCI states of multiple TRPs (TCI 1, TCI 2), TCI1 is associated with TRP1 transmissions and TCI2 is associated with TRP2 transmissions, and the indicated unified TCI state of single TRP applies only to single TRP transmissions from TRP1, there may be ambiguity at the UE regarding the activated/current unified TCI state of single TRP and the unified TCI state of multiple TRP while PDSCH 3 (1313) and PDSCH4 (1314) are received. This problem can be solved by the following various embodiments/solutions.

Scheme V: in some embodiments, the UE may individually update the active/current unified TCI state for single TRP and multi TRP operations such that the active/current unified TCI state for each of these transmissions may be individually updated with only DCI specifying unified TCI states with the same type of transmission scheme. Referring to the example of fig. 13 under scheme V, the beam for receiving PDSCH 3 (1313) is the TCI state (A, B) indicated by the multi-TRP DCI 1 (1301) and the beam for receiving PDSCH4 (1314) is the TCI state C indicated by the single TRP DCI 2 (1302). In this case, the statistics at the UE for the example of fig. 13 may be as follows:

Scheme VI: in some embodiments, the UE may update the active/current TCI state associated with each TRP with each new DCI indication, regardless of the single or multiple TRP transmission scheme. Referring to the example of fig. 13 under scheme VI, the beam for receiving PDSCH 3 (1313) is the TCI state (C, B) indicated by the multi-TRP DCI 1 (1301) and the single-TRP DCI 2 (1302), and the beam for receiving PDSCH 4 (1314) is the TCI state D indicated by the multi-TRP DCI 3 (1303).

Scheme VII: in some embodiments, the UE may update the TCI state of the active/current single TRP with each new DCI indication, regardless of the single TRP transmission scheme or the multi TRP transmission scheme, while the TCI state of the active/current multi TRP may be updated with only the new multi TRP DCI indication. Referring to the example of fig. 13 under scheme VII, the beam for receiving PDSCH 3 (1313) is the TCI state (A, B) indicated by the multi-TRP DCI 1 (1301) and the beam for receiving PDSCH 4 (1314) is the TCI state D indicated by the multi-TRP DCI 3 (1303).

Scheme VIII: in some embodiments, the UE may update the TCI state of the active/current single TRP with only the new single TRP DCI indication, whereas the UE may update the TCI state of the active/current multi TRP with each new DCI indication regardless of the single TRP transmission scheme or the multi TRP transmission scheme. Referring to the example of fig. 13 under scheme VIII, the beam for receiving PDSCH 3 (1313) is the TCI state (C, B) indicated by the multi-TRP DCI 1 (1301) and the single TRP DCI 2 (1302), and the beam for receiving PDSCH 4 (1314) is the TCI state C indicated by the single TRP DCI 2 (1302). All unified TCI state determinations discussed above are also applicable to PDCCH/PUCCH/PUSCH transmissions.

In some embodiments, there may be flexibility in the coexistence of the unified TCI state of the single TRP and the unified TCI state of the multiple TRP of the indication of activation. This means that at each time instance, the UE may only activate the latest indicated unified TCI state, where the latest indicated unified TCI state may be the indicated TCI state of a single TRP or the indicated unified TCI state of multiple TRP. Given a multi-TRP operation with M unified TCI states that have been applied at the UE, beam ambiguity may exist at the UE during the new beam application time when the new DCI schedule indicates a single TRP transmission of one unified TCI state with a scheduling offset greater than the timeduration forqcl threshold. Thus, it may be desirable to determine the UE behavior used to identify the beam in such a scenario. One solution may be to determine the beam from the association of the unified TCI state and TRP that has been indicated. To illustrate, among all indications of multiple TRPs and the unified TCI state that has been activated, a reception beam for single TRP transmission may be determined as the unified TCI state associated with the TRP that has transmitted the new DCI. Another solution may be to pre-determine one of the TRPs and/or the unified TCI state corresponding to the one TRP as a reference TRP and/or a reference unified TCI state for identifying the default beam. The reference TRP and/or unified TCI state may be semi-statistically configured or dynamically indicated/updated to the UE or determined based on specific rules (e.g., CORESETPoolIndex, TCI state pool index of indicated TCI state, TCI state ID, or even a specific order of source resource IDs (e.g., min/max/first/last)).

Furthermore, given a single TRP operation with one unified TCI state already applied at the UE, when multiple TRP transmissions of multiple unified TCI states indicated by the new DCI schedule with a scheduling offset greater than the timeduration forqcl threshold, there may be beam ambiguity at the UE during the new beam application time and it may be necessary to determine the UE behavior used to identify the beam in such scenario. An example of such a scenario is shown in fig. 14.

Fig. 14 illustrates another example of UE behavior when TCI states are applied based on an active/current TCI state set. In some embodiments, the UE determines the beam(s) based on a lowest code point ID among the activated multi-TRP code points in the MAC CE command. In such a scenario, the UE may apply the beam(s) associated with the lowest multi-TRP code point ID in the MAC CE command, regardless of the single TCI state that has been activated. For example, the beam for PDSCH 2 (1401) reception may be a TCI state (A, B), where the TCI state (A, B) corresponds to the first multi-TRP code point in the MAC CE command.

Another solution may be for the UE to apply a unified TCI state of the already activated single TRP to the associated TRP transmissions and for another TRP transmission, determine the beam based on one of the unified TCI states (e.g., selected according to the TCI/TRP association) mapped to the lowest code point ID among the activated multiple TRP code points in the MAC CE command. Referring to fig. 14, under this solution, the beam for PDSCH 2 reception may be a TCI state (F) for TRP1 and a TCI state (B) for TRP2, where TCI state (B) is the corresponding TCI state of TRP2 in the first multiple TRP code point in the MAC CE command.

Another solution may be for the UE to apply the unified TCI state of the already activated single TRP to the associated TRP transmission and for the transmission of another TRP, determine the beam based on the unified TCI state of the lowest code point ID among the activated single TRP code points in the MAC CE command. For example, the beam for PDSCH 2 (1401) reception may be a TCI state (F) for TRP1 and a TCI state (C) for TRP2, where TCI state (C) is the first single TRP code point in the MAC CE command.

Another solution may be to modify the beam application time definition for scheduled PDSCH reception when the scheduling offset is greater than the timeduration forqcl threshold as described previously. For example, when the new DCI schedules single TRP PDSCH reception/multiple TRP PDSCH reception with an indication of one or more uniform TCI states with a scheduling offset greater than a timeduration forqcl threshold, the UE may apply those indicated uniform TCI state(s) to the PDSCH receiving the schedule. Under this modified beam application definition, when the scheduling offset is greater than the timeduration forqcl threshold, there will be no beam ambiguity at the UE for dynamic switching between single and multiple TRP operations in the single DCI scheme. The indicated unified TCI state(s) for each of these scheduled transmissions may be updated separately based on the corresponding scheduling DCI.

Fig. 15 shows an example of UE behavior when TCI state is applied according to a modified beam application time defined solution. The beam for receiving PDSCH 2 (1512) is the TCI state (C) indicated by the scheduling single TRP DCI 2 (1502) and the beam for receiving PDSCH 3 (1513) is the TCI state (D, E) indicated by the scheduling multiple TRP DCI 3 (1503).

In some embodiments, the above-described scheme is applicable to single DCI multi-TRP transmission, where the indicated code point of the MAC CE command may be mapped to one TCI state or a mix of multiple TCI states (i.e., a mix of one TCI state and multiple TCI states indication may be allowed) to facilitate dynamic switching between single TRP transmission and multi-TRP transmission. In some embodiments, such a mixed indication of one TCI state and multiple TCI states in a MAC CE command may not be allowed to prevent beam ambiguity at such a UE. For non-scheduled DCI, such a scheme may be feasible to eliminate beam ambiguity at the UE. However, for scheduling DCI, this limitation will also prevent dynamic switching of single TRP transmissions and multi TRP transmissions. To address the dynamic switching problem while limiting the mixed indication of one TCI state and multiple TCI states in the MAC CE used to schedule the DCI, some embodiments may only allow an indication of one TCI state in the scheduling DCI as an indication of scheduling single TRP transmissions, but in terms of beam/unified TCI state update, one TCI state of the indication may be ignored and not applied to the target channel.

In some embodiments, a new RRC configuration or MAC CE indication may be introduced for the default beam to address this scenario. In some embodiments, the UE may treat such a scenario as an error condition.

In some embodiments, the above-described solution for resolving beam ambiguity may also be applied to multi-DCI multi-TRP transmission with the proposed unified design as described previously, where the indicated code points in each DCI represent all unified TCI states of all TRPs.

Unified TCI state for CG/SPS based transmissions

Two types of scheduling configuration schemes are supported in the 5G NR system. The first type is Dynamic Grant (DG) scheduling, which enables new scheduling decisions to be sent on the PDCCH in each subframe and provides full flexibility in resource allocation and payload size. The second type is based on allocation of Configuration Grants (CG) and semi-persistent scheduling (SPS), which have been used in NR for UL and DL transmissions, respectively, to support ultra-reliable and low-latency communications (URLLC) for industrial communications in the event of transmission of relatively small payloads occurring periodically.

CG/SPS-based scheduling mechanisms facilitate low latency access by avoiding control signaling overhead for scheduling requests and scheduling grants. For example, the scheduling mechanism may semi-statically allocate some resources and transport formats to the UE over a predefined time interval including a certain periodicity and number of occasions. This type of scheduled activation/deactivation is typically through a PDCCH with a semi-persistent cell radio network temporary identifier (C-RNTI). In the rel.17 unified TCI framework, the unified TCI state of the indication of DCI for single TRP transmission is applicable to any UE-specific PDCCH/PDSCH reception including DG/SPS based transmission and PUCCH/PUSCH transmission including DG/CG based transmission.

In some embodiments of the presently disclosed unified TCI framework for multi-TRP operation, the indicated unified TCI state of multi-TRP may also be applied to DG and SPS/CG based transmissions. In the current specification, SPS/CG based transmissions are configured for single TRP transmissions only, meaning that there may be ambiguity at the UE regarding the TCI state of the SPS/CG based transmission occasion when the UE has applied the unified TCI state of the indicated multi TRP transmissions. To solve this problem, one solution may be to assume that the unified TCI state for the indication of single TRP and the unified TCI state for the indication of multiple TRP (simultaneously) coexist (as described previously) and require SPS PDSCH and CG PUSCH transmissions always follow the unified TCI state of the latest indication and single TRP that has been activated.

As another solution, as previously discussed, the UE may use the TCI state/TRP association to determine a unified TCI state of the associated indication of the corresponding TRP and apply the TCI state to SPS/CG-based transmissions of a single TRP. As another solution, the UE may determine and apply one of the indicated unified TCI states of the multiple TRPs to SPS-based transmission of a single TRP using a predetermined rule based on the order of TCI state IDs, code point mapping in the MAC CE, or the order of TCI states (e.g., min/max/specific ID or TCI state). When a dynamic scheduling command is detected, the UE may prioritize dynamic scheduling over semi-persistent scheduling in the particular subframe.

BFR mechanism with unified TCI state

In some embodiments, a Beam Fault Recovery (BFR) mechanism for unified TCI multi-TRP transmission may be based on a TRP-specific primary cell (PCell)/secondary cell (SCell) procedure for the corresponding TRP. This scheme may be applicable to scenarios with multiple unified TCI status indications (where at most one unified TCI status may be indicated for each TRP) as well as scenarios with one common unified TCI status indication shared among all TRPs. In some embodiments of such schemes, the gNB sends a BFR response to the UE, where the BFR response (for each TRP) may contain a new unified TCI state or beam indication. After receiving the BFR response, the UE may apply the new unified TCI state to all target channels and target RSs sharing the indicated unified TCI state, such as PDCCH, PDSCH, aperiodic CSI-RS, PUCCH, PUSCH, and SRS in all CORESETs. The new unified TCI state may be applied X symbols after the BFR response is received at the UE. The value of X may be determined based on the minimum in the SCS configuration of each TRP, which would allow new beam updates per TRP.

In some embodiments, the BFR mechanism for unified TCI multi-TRP transmission may be a simultaneous PCell/SCell procedure for all TRPs. For example, multiple sets of beam-fault detection RSs may be RRC configured such that each set is associated with one TRP. This may be accomplished by each TRP resource grouping and/or sub-pool design context such as previously explained. In some embodiments, the beam fault detection RS set/TRP association may be indicated using an explicit semi-static configuration or a dynamic configuration or an implicit predetermined rule (e.g., according to the order of RS set IDs or coresetpoolndex). For implicit beam fault detection RS determination, the source RS of the indicated TCI state may represent the beam fault detection RS. For new beam identification, multiple RS sets may similarly be RRC configured such that each RS set may be associated with one TRP. For a scenario with one common unified TCI status indication, which may be shared among all TRPs, the scheme may be a more efficient scheme due to less signaling and delay. Under this scheme, the UE may apply the new TCI state to all target channels and target RSs sharing the indicated unified TCI state X symbols after the UE receives the BFR response. The value of X may be determined based on the minimum value in the SCS configuration among all TRPs. This scheme may allow for updating the new TCI state(s) across all TRPs simultaneously. The BFR response from the gNB may contain one common new beam indication or multiple new beam indications corresponding to all TRPs in a simultaneous manner.

In some embodiments, the BFR response transmission may be per TRP (i.e., with one unified new beam indication), in which case the new unified TCI state(s) may be updated for X symbols (e.g., determined based on the minimum in the SCS configuration) after receiving the BFR response from one of the new beams/TRP as a predetermined or semi-statistical configuration or dynamic indication of reference beams/TRP. In some embodiments, a specific rule (e.g., CORESETPoolIndex, TCI state pool index, TCI state ID, or even the order of indicated source resource IDs of TCI states, … …) may be used to indicate the reference TRP/new beam. In some embodiments, the UE may update the new unified TCI state(s) X symbols after receiving the latest BFR response.

Fig. 16 illustrates an example method of communication between a UE and multiple TRPs according to an embodiment. Specifically, the example method of fig. 16 includes UE behavior for TCI state statistics. At 1601, the ue maintains a current Transport Configuration Indicator (TCI) state set including one or more TCI states. At 1602, the ue receives TCI state information, wherein the TCI state information specifies a set of TCI states including an indication of one or more of the activated TCI states. At 1603, the ue updates the current TCI state set based on the indicated TCI state set.

Fig. 17 illustrates another example method of communication between a UE and multiple TRPs according to an embodiment. In particular, the example method of fig. 17 includes UE behavior for TCI state/TRP association. At 1701, the ue receives Transmission Configuration Indicator (TCI) state information, wherein the TCI state information specifies a set of TCI states including an indication of one or more active TCI states. At 1702, the ue receives an indication of an association between an indicated TCI state set and one or more TRPs. At 1703, the ue identifies one or more of the multiple TRPs based on the associated indication to apply the configuration of the indicated TCI state set.

In some embodiments, the UE receives the TCI state information and the associated indication via a Dynamic Control Information (DCI) message, wherein the DCI message includes a single TCI field conveying a set of TCI states specifying the indication and a code point value of the associated indication.

In some embodiments, the UE receives the indication of the association based on at least one of Radio Resource Control (RRC) signaling, a Medium Access Control (MAC) Control Element (CE) command, and a Dynamic Control Information (DCI) message.

In some embodiments, the step of identifying, by the UE, one or more of the multiple TRPs based on the indication of the association comprises: a predetermined order-based rule is applied to associate the indicated TCI state set with one or more TRPs.

In some embodiments, the example method includes: receiving, by the UE, a Beam Fault Recovery (BFR) response, wherein the BFR response includes an indication of an updated TCI state set of indications, and an updated association between the updated TCI state set of indications and the updated one or more of the multiple TRPs; and applying the configuration of the updated indicated TCI state set to the updated one or more TRPs X symbols after receiving the BFR response, wherein X is based on the minimum in the subcarrier spacing SCS () configuration of each TRP or the minimum of all the multiple TRPs.

In some embodiments, the target resources for performing UL transmissions to the one or more TRPs comprise Sounding Reference Signal (SRS) target resources and the associated indication comprises a Radio Resource Control (RRC) parameter, wherein the RRC parameter associates the SRS target resources with the indicated TCI state set or the SRS target resources with the one or more TRPs.

In some embodiments, the target resources for performing DL reception from the one or more TRPs comprise channel state information reference signal (CSI-RS) target resources and the associated indication comprises an RRC parameter, wherein the RRC parameter associates the CSI-RS target resources with the indicated TCI state set or associates the CSI-RS target resources with the one or more TRPs.

According to an embodiment, an example User Equipment (UE) includes a processor; a memory comprising instructions, wherein the instructions, when executed by a processor, cause a UE to: receiving transmission configuration indicator TCI () state information, wherein the TCI state information specifies an indicated TCI state set, the indicated TCI state set comprising one or more active TCI states; receiving an indication of an association between the indicated TCI state set and one or more of a plurality of Transmission and Reception Points (TRPs) (multiple TRPs); and identifying one or more of the multiple TRPs to apply the configuration of the indicated TCI state set based on the associated indication.

In some embodiments, the example UE receives the TCI state information and the associated indication via a dynamic control information, DCI, message, wherein the DCI message includes a single TCI field conveying a set of TCI states specifying the indication and a code point value of the associated indication.

In some embodiments, the example UE receives the indication of the association based on at least one of Radio Resource Control (RRC) signaling, a Medium Access Control (MAC) Control Element (CE) command, and a Dynamic Control Information (DCI) message.

In some embodiments, identifying one or more of the multiple TRPs based on the associated indication comprises: a predetermined order-based rule is applied to associate the indicated TCI state set with one or more TRPs.

In some embodiments, the instructions, when executed by the processor, further cause the UE to: receiving a Beam Fault Recovery (BFR) response, wherein the BFR response includes an indication of an updated TCI state set of indications, and an updated association between the updated TCI state set of indications and the updated one or more of the multiple TRPs; and applying a configuration of the updated indicated TCI state set to the updated one or more TRPs for X symbols after receiving the BFR response, wherein X is based on a minimum in a subcarrier spacing (SCS) configuration of each TRP or a minimum of all the multiple TRPs.

Fig. 18 illustrates another example method of communication between a UE and multiple TRPs according to an embodiment. Specifically, the example method of fig. 18 includes UE behavior for applying a default TCI state. At 1801, the ue receives a Dynamic Control Information (DCI) message scheduling reception of a Physical Downlink Shared Channel (PDSCH) from a TRP of the multiple TRPs. At 1802, the ue determines at least one of (a) an application and (b) an application: (a) The DCI message does not include Transmission Configuration Indicator (TCI) status information, and (b) the DCI message schedules a PDSCH before a duration for applying quasi-parity (QCL) information received in the DCI to PDSCH processing. At 1803, in response to determining at least one of (a) application and (b) application, the UE determines a default TCI state. At 1804, the ue applies a configuration of a default TCI state to perform at least one of Uplink (UL) transmission and Downlink (DL) reception with one or more of the multiple TRPs.

In some embodiments, an example method includes: receiving, by the UE, a list of one or more TCI states via Radio Resource Control (RRC) signaling; and receiving, by the UE, a Medium Access Control (MAC) Control Element (CE) command, wherein the MAC CE command activates TCI states from a list of one or more TCI states, wherein each of the activated TCI states is associated with a Physical Cell ID (PCI) value, wherein the PCI value is different from a PCI value of the serving cell.

In some embodiments, each of the activated TCI states is mapped to a code point value, and the UE determines the default TCI state based on a lowest code point value among the code point values mapped to the plurality of activated TCI states.

In some embodiments, an example method includes: receiving, by the UE, a list of one or more TCI states via Radio Resource Control (RRC) signaling; and receiving, by the UE, a medium access control, MAC, control element, CE, command, wherein the MAC CE command activates TCI states from a list of one or more TCI states, wherein at least one of the activated TCI states is associated with a PCI value, wherein the PCI value is different from a PCI value of the serving cell.

In some embodiments, an example method includes: receiving, by the UE via radio resource control, RRC, signaling, a list of one or more TCI states, wherein each of the one or more TCI states corresponds to a core belonging to at least one of a first pool of control resources (core) and a second pool of cores; and receiving, by the UE, a Medium Access Control (MAC) Control Element (CE) command, wherein the MAC CE command activates a first TCI state corresponding to a CORESET in the first CORESET pool and a second TCI state corresponding to a CORESET in the second CORESET pool, wherein: the multiple TRPs include an intra-cell TRP and an inter-cell TRP, wherein the intra-cell TRP is associated with a first Physical Cell ID (PCI) value of a serving cell, the inter-cell TRP is associated with a second PCI value different from the first PCI value, the UE determines a default TCI state for performing DL transmission or UL reception of the intra-cell TRP based on a CORESET corresponding to the first TCI state, and the UE determines a default TCI state for performing DL transmission or UL reception of the inter-cell TRP based on the CORESET corresponding to the second TCI state.

In some embodiments, the UE determines a default TCI state for performing DL transmission or UL reception with the cell-to-cell TRP based on a lowest CORESET ID among CORESETs corresponding to the second set of TCI states.

Fig. 19 is a block diagram of an electronic device in a network environment 1900 according to an embodiment. The electronic device of fig. 19 may include a UE that performs the functions and embodiments described herein, such as those shown in fig. 2-18.

Referring to fig. 19, an electronic device 1901 in a network environment 1900 may communicate with the electronic device 1902 via a first network 1998 (e.g., a short-range wireless communication network) or with an electronic device 1904 or a server 1908 via a second network 1999 (e.g., a long-range wireless communication network). The electronic device 1901 may communicate with the electronic device 1904 via a server 1908. The electronic device 1901 may include a processor 1920, a memory 1930, an input device 1950, a sound output device 1955, a display device 1960, an audio device 1970, a sensor module 1976, an interface 1977, a haptic module 1979, a camera module 1980, a power management module 1988, a battery 1989, a communication module 1990, a Subscriber Identity Module (SIM) 1996, or an antenna module 1997. In one embodiment, at least one of the components (e.g., display device 1960 or camera module 1980) may be omitted from electronic device 1901, or one or more other components may be added to electronic device 1901. Some components may be implemented as a single Integrated Circuit (IC). For example, the sensor module 1976 (e.g., a fingerprint sensor, iris sensor, or illuminance sensor) may be embedded in a display device 1960 (e.g., a display).

The processor 1920 may execute software (e.g., a program 1940) to control at least one other component (e.g., hardware or software component) of the electronic device 1901 in conjunction with the processor 1920, and may perform various data processing or calculations.

As at least part of the data processing or computation, the processor 1920 may load commands or data received from another component (e.g., the sensor module 1946 or the communication module 1990) into the volatile memory 1932, process commands or data stored in the volatile memory 1932, and store the resulting data in the nonvolatile memory 1934. The processors 1920 may include a main processor 1921 (e.g., a Central Processing Unit (CPU) or an Application Processor (AP)) and an auxiliary processor 1923 (e.g., a Graphics Processor (GPU), an Image Signal Processor (ISP), a sensor hub processor, or a Communication Processor (CP)), the auxiliary processor 1923 being operable independently of the main processor 1921 or in conjunction with the main processor 1921. Additionally or alternatively, the auxiliary processor 1923 may be adapted to consume less power than the main processor 1921 or perform certain functions. The auxiliary processor 1923 may be implemented separately from the main processor 1921 or as part of the main processor 1921.

The auxiliary processor 1923 (rather than the main processor 1921) may control at least some of the functions or states associated with at least one of the components of the electronic device 1901 (e.g., the display device 1960, the sensor module 1976, or the communication module 1990) while the main processor 1921 is in an inactive (e.g., sleep) state, or the auxiliary processor 1923 may control at least some of the functions or states associated with at least one of the components of the electronic device 1901 (e.g., the display device 1960, the sensor module 1976, or the communication module 1990) with the main processor 1921 while the main processor 1921 is in an active state (e.g., executing an application). The auxiliary processor 1923 (e.g., an image signal processor or a communication processor) may be implemented as part of another component (e.g., a camera module 1980 or a communication module 1990) functionally associated with the auxiliary processor 1923.

The memory 1930 may store various data used by at least one component of the electronic device 1901 (e.g., the processor 1920 or the sensor module 1976). The various data may include, for example, software (e.g., program 1940) and input data or output data for commands associated therewith. Memory 1930 may include volatile memory 1932 or nonvolatile memory 1934. Nonvolatile memory 1934 can include internal memory 1936 and/or external memory 1938.

Programs 1940 may be stored as software in memory 1930 and may include, for example, an Operating System (OS) 1942, middleware 1944, or applications 1946.

The input device 1950 may receive commands or data from outside the electronic device 1901 (e.g., a user) to be used by another component of the electronic device 1901 (e.g., the processor 1920). Input device 1950 may include, for example, a microphone, a mouse, or a keyboard.

The sound output device 1955 may output a sound signal to the outside of the electronic device 1901. The sound output device 1955 may include, for example, a speaker or a receiver. The speaker may be used for general purposes, such as playing multimedia or recording, and the receiver may be used to receive incoming calls. The receiver may be implemented separate from the speaker or as part of the speaker.

The display device 1960 may visually provide information to the outside (e.g., a user) of the electronic device 1901. The display device 1960 may include, for example, a display, a holographic device, or a projector, and a control circuit for controlling a respective one of the display, the holographic device, and the projector. The display device 1960 may include touch circuitry adapted to detect touches or sensor circuitry (e.g., pressure sensors) adapted to measure the strength of forces caused by touches.

The audio device 1970 may convert sound into electrical signals and vice versa. The audio device 1970 may obtain sound via the input device 1950, or output sound via the sound output device 1955 or headphones of the external electronic device 1902 that are directly (e.g., wired) or wirelessly coupled with the electronic device 1901.

The sensor module 1976 may detect an operational state (e.g., power or temperature) of the electronic device 1901 or an environmental state (e.g., a state of a user) external to the electronic device 1901 and then generate an electrical signal or data value corresponding to the detected state. The sensor module 1976 may include, for example, a gesture sensor, a gyroscope sensor, an atmospheric pressure sensor, a magnetic sensor, an acceleration sensor, a grip sensor, a proximity sensor, a color sensor, an Infrared (IR) sensor, a biometric sensor, a temperature sensor, a humidity sensor, or an illuminance sensor.

The interface 1977 may support one or more specified protocols for the electronic device 1901 to interface directly (e.g., wired) or wirelessly with the external electronic device 1902. Interface 1977 may include, for example, a High Definition Multimedia Interface (HDMI), a Universal Serial Bus (USB) interface, a Secure Digital (SD) card interface, or an audio interface.

The connection end 1978 may include a connector via which the electronic device 1901 may be physically connected with the external electronic device 1902. The connection end 1978 may include, for example, an HDMI connector, a USB connector, an SD card connector, or an audio connector (e.g., a headphone connector).

The haptic module 1979 may convert the electrical signal into a mechanical stimulus (e.g., vibration or movement) or an electrical stimulus that may be recognized by the user via a tactile or kinesthetic sensation. The haptic module 1979 may include, for example, a motor, a piezoelectric element, or an electrostimulator.

The camera module 1980 may capture still images or moving images. The camera module 1980 may include one or more lenses, an image sensor, an image signal processor, or a flash. The power management module 1988 may manage power supplied to the electronic device 1901. The power management module 1988 may be implemented as at least part of a Power Management Integrated Circuit (PMIC), for example.

A battery 1989 may power at least one component of the electronic device 1901. The battery 1989 may include, for example, a primary non-rechargeable battery, a rechargeable secondary battery, or a fuel cell.

The communication module 1990 may support establishing a direct (e.g., wired) communication channel or a wireless communication channel between the electronic device 1901 and an external electronic device (e.g., the electronic device 1902, the electronic device 1904, or the server 1908) and performing communication via the established communication channel. General purpose medicine The communications module 1990 may include one or more communications processors that may operate independently of the processor 1920 (e.g., an AP) and support direct (e.g., wired) or wireless communications. The communication module 1990 may include a wireless communication module 1992 (e.g., a cellular communication module, a short-range wireless communication module, or a Global Navigation Satellite System (GNSS) communication module) or a wired communication module 1994 (e.g., a Local Area Network (LAN) communication module or a Power Line Communication (PLC) module). A respective one of these communication modules may be connected via a first network 1998 (e.g., a short-range communication network such as bluetooth ^TM Wireless fidelity (Wi-Fi) direct or infrared data association (IrDA) standard) or a second network 1999 (e.g., a long-range communications network such as a cellular network, the internet, or a computer network (e.g., a LAN or Wide Area Network (WAN)) with external electronic devices. These various types of communication modules may be implemented as a single component (e.g., a single IC), or may be implemented as multiple components (e.g., multiple ICs) separate from one another. The wireless communication module 1992 can use user information (e.g., an International Mobile Subscriber Identity (IMSI)) stored in the subscriber identity module 1996 to identify and authenticate the electronic device 1901 in a communication network, such as the first network 1998 or the second network 1999.

The antenna module 1997 may send signals or power to the outside of the electronic device 1901 (e.g., an external electronic device) or receive signals or power from the outside of the electronic device 1901 (e.g., an external electronic device). The antenna module 1997 may comprise one or more antennas and thus, at least one antenna suitable for a communication scheme used in a communication network, such as the first network 1998 or the second network 1999, may be selected, for example, by the communication module 1990 (e.g., the wireless communication module 1992). Signals or power may then be transmitted or received between the communication module 1990 and the external electronic device via the selected at least one antenna.

Commands or data may be sent or received between the electronic device 1901 and the external electronic device 1904 via the server 1908 in conjunction with the second network 1999. Each of the electronic devices 1902 and 1904 may be the same type as or different type of device than the electronic device 1901. All or some of the operations to be performed at the electronic device 1901 may be performed at one or more of the external electronic device 1902, the external electronic device 1904, or the server 1908. For example, if the electronic device 1901 should automatically perform a function or service or should perform a function or service in response to a request from a user or another device, the electronic device 1901 may request the one or more external electronic devices to perform at least part of the function or service instead of or in addition to the function or service, or the electronic device 1901 may request the one or more external electronic devices to perform at least part of the function or service. The one or more external electronic devices that received the request may perform the requested at least part of the function or service, or perform additional functions or additional services related to the request, and transmit the result of the performing to the electronic device 1901. The electronic device 1901 may provide the results, with or without further processing of the results, as at least a portion of a reply to the request. To this end, for example, cloud computing, distributed computing, or client-server computing techniques may be used.

Fig. 20 shows a system including a UE 2005 and a gNB 2010 in communication with each other. The UE may include a radio 2015 and processing circuitry (or means for processing) 2020, wherein the processing circuitry 2020 may perform various methods disclosed herein, e.g., the methods shown in fig. 2-18. For example, the processing circuit 2020 may receive a transmission from a network node (gNB) 2010 via a radio 2015, and the processing circuit 2020 may send a signal to the gNB 2010 via the radio 2015.

Embodiments of the subject matter and the operations described in this specification can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them. Embodiments of the subject matter described in this specification can be implemented as one or more computer programs (i.e., one or more modules of computer program instructions) encoded on a computer storage medium for execution by, or to control the operation of, data processing apparatus. Alternatively or additionally, the program instructions may be encoded on a manually-generated propagated signal (e.g., a machine-generated electrical, optical, or electromagnetic signal) that is generated to encode information for transmission to suitable receiver apparatus for execution by data processing apparatus. The computer storage medium may be or be included in a computer readable storage device, a computer readable storage substrate, a random or serial access memory array or device, or a combination of computer readable storage devices, computer readable storage substrates, random or serial access memory arrays or devices. Furthermore, while the computer storage medium is not a propagated signal, the computer storage medium may be a source or destination of computer program instructions encoded in an artificially generated propagated signal. Computer storage media may also be or be included in one or more separate physical components or media (e.g., multiple CDs, disks, or other storage devices). Additionally, the operations described in this specification may be implemented as operations performed by a data processing apparatus on data stored on one or more computer readable storage devices or received from other sources.

Although this description may contain many specific implementation details, the implementation details should not be construed as limiting the scope of any claimed subject matter, but rather as descriptions of features specific to particular embodiments. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Furthermore, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

Similarly, although operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In some cases, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

Thus, particular embodiments of the subject matter have been described herein. Other embodiments are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results. In addition, the processes depicted in the accompanying drawings do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In some embodiments, multitasking and parallel processing may be advantageous.

As will be recognized by those skilled in the art, the innovative concepts described herein can be modified and varied over a wide range of applications. Accordingly, the scope of the claimed subject matter should not be limited to any of the specific exemplary teachings discussed above, but is instead defined by the appended claims.

Claims

1. A method of communicating with a plurality of transmit and receive point-multiple TRPs, the method comprising:

receiving, by a user equipment UE, transmission configuration indicator, TCI, state information, wherein the TCI state information specifies an indicated set of TCI states, the indicated set of TCI states comprising one or more active TCI states;

receiving, by the UE, an indication of an association between the indicated TCI state set and one or more of the multiple TRPs; and is also provided with

Identifying, by the UE, the one or more of the multiple TRPs based on the associated indication to apply a configuration of the indicated TCI state set.

2. The method of claim 1, wherein the UE receives the TCI state information and the associated indication via a dynamic control information, DCI, message, wherein the DCI message includes a single TCI field conveying a code point value specifying the indicated set of TCI states and the associated indication.

3. The method of claim 1, wherein the UE receives the indication of the association based on at least one of radio resource control, RRC, signaling, medium access control, MAC, control element, CE, command, and dynamic control information, DCI, message.

4. The method of claim 1, wherein the step of identifying, by the UE, the one or more of the multiple TRPs based on the associated indication comprises: a predetermined order-based rule is applied to associate the indicated set of TCI states with the one or more TRPs.

5. The method of claim 1, further comprising:

receiving, by the UE, a beam fault recovery, BFR, response, wherein the BFR response includes an updated set of indicated TCI states, and an indication of updated association between the updated set of indicated TCI states and the updated one or more of the plurality of TRPs; and is also provided with

The configuration of the updated indicated TCI state set is applied to the updated one or more TRPs by X symbols after receiving the BFR response, wherein X is based on a minimum in a subcarrier spacing SCS configuration for each TRP or a minimum of all of the multiple TRPs.

6. The method according to claim 1, wherein:

the target resources for performing UL transmissions to the one or more TRPs include sounding reference signal, SRS, target resources, and

the associated indication includes a radio resource control, RRC, parameter, wherein the RRC parameter associates the SRS target resource with the indicated set of TCI states or associates the SRS target resource with the one or more TRPs.

7. The method according to claim 1, wherein:

the target resources for performing DL reception from the one or more TRPs include channel state information reference signal CSI-RS target resources, and

the indication of the association includes an RRC parameter, wherein the RRC parameter associates the CSI-RS target resource with the indicated TCI state set or associates the CSI-RS target resource with the one or more TRPs.

8. A user equipment, UE, comprising:

a processor;

a memory comprising instructions, wherein the instructions, when executed by the processor, cause the UE to:

receiving transmission configuration indicator, TCI, state information, wherein the TCI state information specifies an indicated set of TCI states, the indicated set of TCI states comprising one or more active TCI states;

receiving an indication of an association between the indicated TCI state set and one or more of a plurality of transmission and reception points, TRPs, multiple TRPs; and is also provided with

Identifying the one or more of the multiple TRPs based on the associated indication to apply a configuration of the indicated TCI state set.

9. The UE of claim 8, wherein the UE receives the TCI state information and the associated indication via a dynamic control information, DCI, message, wherein the DCI message includes a single TCI field conveying a code point value specifying the indicated set of TCI states and the associated indication.

10. The UE of claim 8, wherein the UE receives the indication of the association based on at least one of radio resource control, RRC, signaling, medium access control, MAC, control element, CE, commands, and dynamic control information, DCI, messages.

11. The UE of claim 8, wherein identifying the one or more of the multiple TRPs based on the associated indication comprises: a predetermined order-based rule is applied to associate the indicated set of TCI states with the one or more TRPs.

12. The UE of claim 8, wherein the instructions, when executed by the processor, further cause the UE to:

receiving a beam fault recovery, BFR, response, wherein the BFR response includes an updated TCI state set of indications, and an indication of updated associations between the updated TCI state set of indications and updated one or more of the plurality of TRPs; and

13. The UE of claim 8, wherein:

14. The UE of claim 8, wherein:

15. A method of communicating with a plurality of transmit and receive point-multiple TRPs, the method comprising:

receiving, by a user equipment UE, a dynamic control information, DCI, message scheduling reception of a physical downlink shared channel, PDSCH, from TRPs of the multiple TRPs;

determining, by the UE, at least one of (a) an application and (b) an application:

(a) The DCI message does not include transmission configuration indicator TCI status information, and

(b) The DCI message schedules a PDSCH before a duration for applying quasi-co-located QCL information received in the DCI to PDSCH processing;

Determining, by the UE, a default TCI state in response to determining at least one of (a) an application and (b) an application; and is also provided with

The configuration of the default TCI state is applied by the UE to perform at least one of uplink UL transmission and downlink DL reception with one or more of the multiple TRPs.

16. The method of claim 15, further comprising:

receiving, by the UE, a list of one or more TCI states via radio resource control, RRC, signaling; and is also provided with

Receiving, by the UE, a medium access control, MAC, control element, CE, command, wherein the MAC CE command activates a TCI state from the list of one or more TCI states,

wherein each of the activated TCI states is associated with a physical cell ID PCI value, wherein the PCI values are different from the PCI values of the serving cell.

17. The method of claim 16, wherein each of the activated TCI states is mapped to a code point value and the UE determines the default TCI state based on a lowest code point value among code point values mapped to a plurality of activated TCI states.

18. The method of claim 15, further comprising:

wherein at least one of the active TCI states is associated with a PCI value, wherein the PCI value is different from a PCI value of the serving cell.

19. The method of claim 15, further comprising:

receiving, by the UE via radio resource control, RRC, signaling, a list of one or more TCI states, wherein each of the one or more TCI states corresponds to a CORESET belonging to at least one of a first CORESET pool and a second CORESET pool; and

receiving, by the UE, a medium access control, MAC, control element, CE, command, wherein the MAC CE command activates a first TCI state corresponding to a CORESET in a first CORESET pool and a second TCI state corresponding to a CORESET in a second CORESET pool,

wherein:

the multiple TRP includes an intra-cell TRP associated with a first physical cell ID PCI value of a serving cell and an inter-cell TRP associated with a second PCI value different from the first PCI value,

The UE determining a default TCI state for performing DL transmission or UL reception with the TRP in the cell based on the CORESET corresponding to the first TCI state, and

the UE determines a default TCI state for performing DL transmission or UL reception with the inter-cell TRP based on CORESET corresponding to the second TCI state.

20. The method of claim 19, wherein the UE determines the default TCI state for performing DL transmission or UL reception with the inter-cell TRP based on a lowest CORESET ID among CORESETs corresponding to a second set of TCI states.